DESIGN OF DISCOVERY REFERENCE SIGNALS

BACKGROUND

[0001] Wireless systems typically include multiple User Equipment (UE) devices communicatively coupled to one or more Base Stations (BS). The one or more BSs may be Long Term Evolved (LTE) evolved NodeBs (eNB) or New Radio (NR) next generation NodeBs (gNB) that can be communicatively coupled to one or more UEs by a Third- Generation Partnership Project (3 GPP) network.

[0002] Next generation wireless communication systems are expected to be a unified network/system that is targeted to meet vastly different and sometimes conflicting performance dimensions and services. New Radio Access Technology (RAT) is expected to support a broad range of use cases including Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), Mission Critical Machine Type Communication (uMTC), and similar service types operating in frequency ranges up to 100 GHz.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Features and advantages of the disclosure will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the disclosure; and, wherein:

[0004] FIGS. 1A and IB illustrate a discovery reference signal (DRS) structure in Release 13 (Rel-13) enhanced Machine Type Communication (eMTC) for a frequency division duplex (FDD) system and a time division duplex (TDD) system, respectively, in accordance with an example;

[0005] FIG. 2 illustrates a discovery reference signal (DRS) structure for MulteFire 1.0 in accordance with an example;

[0006] FIGS. 3A and 3B illustrate a first alternative of a discovery reference signal (DRS) structure in accordance with an example;

[0007] FIGS. 4A and 4B illustrate a second alternative of a discovery reference signal (DRS) structure in accordance with an example; [0008] FIG. 5 illustrates a second alternative of a discovery reference signal (DRS) structure in accordance with an example;

[0009] FIGS. 6A and 6B illustrate a third alternative of a discovery reference signal (DRS) structure in accordance with an example;

[0010] FIG. 7 illustrates a discovery reference signal (DRS) structure in which physical broadcast channel (PBCH) signals are repeated in accordance with an example;

[0011] FIG. 8 illustrates a discovery reference signal (DRS) structure in which a master information block (MIB) is rate matched to more symbols in accordance with an example;

[0012] FIG. 9 illustrates a discovery reference signal (DRS) design in which the DRS occupies multiple subframes in accordance with an example;

[0013] FIGS. 10A and 10B illustrate a discovery reference signal (DRS) design in which the DRS occupies multiple subframes in accordance with an example;

[0014] FIGS. 11 A, 11B, 11C and 11D illustrate a discovery reference signal (DRS) design in which the DRS occupies multiple subframes in accordance with an example;

[0015] FIGS. 12A and 12B illustrate a fourth alternative of a discovery reference signal (DRS) structure in accordance with an example;

[0016] FIG. 13 illustrates a fifth alternative of a discovery reference signal (DRS) structure in accordance with an example;

[0017] FIG. 14 illustrates a further fifth alternative of a discovery reference signal (DRS) structure in accordance with an example;

[0018] FIG. 15 illustrates yet a further fifth alternative of a discovery reference signal (DRS) structure in accordance with an example;

[0019] FIG. 16 illustrates two discovery reference signals (DRS) over resource blocks in a frequency domain in accordance with an example;

[0020] FIG. 17 illustrates a discovery reference signal (DRS) structure in which single- interval listen before talk (LBT) is performed before each DRS subframe in accordance with an example; [0021] FIG. 18 illustrates an extended discovery reference signal (eDRS) window in accordance with an example;

[0022] FIG. 19 depicts functionality of an eNodeB operable to encode a discovery reference signal (DRS) for transmission to a user equipment (UE) in accordance with an example;

[0023] FIG. 20 depicts functionality of an eNodeB operable to encode a discovery reference signal (DRS) for transmission in a wideband coverage enhancement for a MulteFire system in accordance with an example;

[0024] FIG. 21 depicts a flowchart of a machine readable storage medium having instructions embodied thereon for encoding a discovery reference signal (DRS) for transmission in a wideband coverage enhancement for a MulteFire system in accordance with an example;

[0025] FIG. 22 illustrates an architecture of a wireless network in accordance with an example;

[0026] FIG. 23 illustrates a diagram of a wireless device (e.g., UE) in accordance with an example;

[0027] FIG. 24 illustrates interfaces of baseband circuitry in accordance with an example; and

[0028] FIG. 25 illustrates a diagram of a wireless device (e.g., UE) in accordance with an example.

[0029] Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the technology is thereby intended. DETAILED DESCRIPTION

[0030] Before the present technology is disclosed and described, it is to be understood that this technology is not limited to the particular structures, process actions, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular examples only and is not intended to be limiting. The same reference numerals in different drawings represent the same element. Numbers provided in flow charts and processes are provided for clarity in illustrating actions and operations and do not necessarily indicate a particular order or sequence.

DEFINITIONS

[0031] As used herein, the term "User Equipment (UE)" refers to a computing device capable of wireless digital communication such as a smart phone, a tablet computing device, a laptop computer, a multimedia device such as an iPod Touch®, or other type computing device that provides text or voice communication. The term "User Equipment (UE)" may also be referred to as a "mobile device," "wireless device," of "wireless mobile device."

[0032] As used herein, the term "Base Station (BS)" includes "Base Transceiver Stations (BTS)," "NodeBs," "evolved NodeBs (eNodeB or eNB)," and/or "next generation

NodeBs (gNodeB or gNB)," and refers to a device or configured node of a mobile phone network that communicates wirelessly with UEs.

[0033] As used herein, the term "cellular telephone network," "4G cellular," "Long Term Evolved (LTE)," "5G cellular" and/or "New Radio (NR)" refers to wireless broadband technology developed by the Third Generation Partnership Project (3GPP).

EXAMPLE EMBODIMENTS

[0034] An initial overview of technology embodiments is provided below and then specific technology embodiments are described in further detail later. This initial summary is intended to aid readers in understanding the technology more quickly but is not intended to identify key features or essential features of the technology nor is it intended to limit the scope of the claimed subject matter.

Design of Discovery Reference Signals for Unlicensed Internet of Things or

Wideband Coverage Enhancement (WCE) [0035] The present technology relates to Long Term Evolution (LTE) operation in an unlicensed spectrum in MulteFire (MF), and specifically Internet of Things (IoT) operating in the unlicensed spectrum, or Unlicensed-IoT (U-IoT). For example, the U-IoT discovery signal design can use either listen before talk (LBT) or frequency hopping

[0036] In one example, IoT is envisioned as a significantly important technology component, by enabling connectivity between many devices. IoT has wide applications in various scenarios, including smart cities, smart environment, smart agriculture, and smart health systems. 3GPP has standardized two designs to support IoT services ~ enhanced Machine Type Communication (eMTC) and NarrowBand IoT (NB-IoT). As eMTC and NB-IoT UEs will be deployed in large numbers, lowering the cost of these UEs is a key enabler for the implementation of IoT. Also, low power consumption is desirable to extend the life time of the UE's battery. In addition, there are substantial use cases of devices deployed deep inside buildings, which would necessitate coverage enhancement in comparison to the defined LTE cell coverage footprint. In summary, eMTC and NB- IoT techniques are designed to ensure that the UEs have low cost, low power

consumption and enhanced coverage.

[0037] With respect to LTE operation in the unlicensed spectrum, both Release 13 (Rel- 13) eMTC and NB-IoT operates in a licensed spectrum. On the other hand, the scarcity of licensed spectrum in low frequency band results in a deficit in the data rate boost. Thus, there are emerging interests in the operation of LTE systems in unlicensed spectrum. Potential LTE operation in the unlicensed spectrum includes, but not limited to, Carrier Aggregation based licensed assisted access (LAA) or enhanced LAA (eLAA) systems, LTE operation in the unlicensed spectrum via dual connectivity (DC), and a standalone LTE system in the unlicensed spectrum, where LTE-based technology solely operates in the unlicensed spectrum without necessitating an "anchor" in licensed spectrum - a system that is referred to as MulteFire. To extend the benefits of LTE IoT designs into unlicensed spectrum, MulteFire 1.1 is expected to specify the design for Unlicensed-IoT (U-IoT).

[0038] With respect to coexistence in the unlicensed spectrum, the unlicensed frequency band of current interest is the sub-1 GHz band and the ~2.4GHz band for U-IoT, which has spectrum with global availability. The regulations are different for different regions and bands, e.g., different maximal channel bandwidth, LBT, duty cycling, frequency hopping and power limitations can be necessitated. For example, in Europe, it is necessary to have either LBT or <0.1% duty cycle for frequency hopping spread spectrum (FHSS) modulation with channel bandwidth no less than 100kHz within 863-870MHz, and for digital modulation with channel bandwidth no greater than 100kHz within 863- 870MHz. Either LBT or frequency hopping can be used for coexistence with other unlicensed band transmission.

[0039] With respect to discovery reference signals (DRS), in the LTE system, if a small cell is considered as the secondary cell (SCell) by all UEs served by the small cell, then the small cell can perform state transition between ON/OFF. The Release 12 (Rel-12) discovery reference signal (DRS) was designed to facilitate fast transition from the OFF state to the ON state, by transmitting minimal signals for radio resource management (RRM) measurement and reporting during the OFF state. The Rel-12 DRS consists of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a cell- specific reference signal (CRS), and optionally a channel state information reference signal (CSI-RS). A DRS measurement timing configuration (DMTC) can be configured by an eNodeB, which can have an occasion of 6ms and periodicity of 40ms, 80ms or 160ms. The UEs can expect the DRS to be received within DMTC.

[0040] FIGS. 1A and IB illustrate an example of a discovery reference signal (DRS) structure in Release 13 (Rel-13) enhanced Machine Type Communication (eMTC) for a frequency division duplex (FDD) system and a time division duplex (TDD) system, respectively. FIG. 1 A illustrates DRS in FDD. FIG. IB illustrates DRS in TDD. In the Rel-13 eMTC design, the DRS can have a normal cyclic prefix (CP). As shown, symbols carrying a master information block (MIB) can be repeated, as compared to Rel-12 LTE, in order to enhance the coverage. The PSS/SSS can follow the Rel-12 LTE design (e.g., no additional repetitions).

[0041] FIG. 2 illustrates an example of a discovery reference signal (DRS) structure for MulteFire 1.0. As shown, more OFDM symbols (e.g., symbols 4 and 11) can be used for a master information block (MIB) transmission, as compared to Rel-12 LTE, in order to improve a MIB detection performance in the unlicensed spectrum. Different from Rel-13 eMTC, the symbols are not just repeated, but rate matching can be performed to map the modulation symbols to more resource elements (REs). In additional, the PSS/SSS can be repeated, where each DRS can consist of 2 PSS and 2 SSS symbols. Due to LBT, the PSS/SSS may not be transmitted as frequently as in legacy LTE, and thus more PSS/SSS symbols can help improve the cell detection and synchronization performance.

[0042] The present technology describes a DRS design for U-IoT, considering both the aspects of coverage enhancement and the LBT impact. In addition, the DRS design can be used for wideband coverage enhancement.

[0043] In one configuration, in the DRS design for U-IoT, the DRS can span over one or multiple subframes. The DRS can include the PSS, SSS, CRS and/or a physical broadcast channel (PBCH). The DRS in one subframe within the DRS duration can have one of the following structures. In a first alternative, the DRS on the considered subframe can consist of PSS/SSS/CRS/PBCH, where the PSS/SSS can be the same as the PSS/SSS in LAA DRS, e.g., the PSS presents at symbol 6 and the SSS presents at symbol 5. The CRS can be the same as the CRS in Rel-12 DRS. A MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13} . In a second alternative, the DRS on the considered subframe can consist of PSS/SSS/CRS/PBCH, where in addition to the PSS/SSS which are the same as the PSS/SSS in LAA DRS (e.g., PSS at symbol 6 and SSS at symbol 5), additional PSS/SSS can be added to symbol 2 and/or 3. The CRS can be the same as the CRS in Rel-12 DRS. A MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 4, 11, 12, 13} if symbols 2 and 3 are used for additional PSS/SSS, or {7, 8, 9, 10, 0, 1, 2, 4, 11, 12, 13} if symbol 3 is used for additional PSS/SSS, or {7, 8, 9, 10, 0, 1, 3, 4, 11, 12, 13} if symbol 2 is used for additional PSS/SSS. In a third alternative, the DRS on the considered subframe can consist of CRS/PBCH, where the CRS is the same as the CRS in Rel-12 DRS. A MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 11, 12, 13}.

[0044] In one example, for the three alternative described above, when the MIB is transmitted over symbols in addition to symbols 7, 8, 9, and 10, the following methods to carry MIB can be considered: the PBCH symbols can be repeated, similar to Rel-13 eMTC and/or the MIB can be rate matched to these symbols, similar to DRS in MulteFire 1.0. [0045] In one example, when the DRS has a duration of no more than one subframe, the DRS structure can be any one of the above proposed alternatives. When the DRS has a duration of more than one subframe, any combinations of the above proposed alternatives in different subframes can be considered. For example, the DRS can be repeated over multiple subframes, where the DRS in one subframe can follow one the above proposed structures (e.g., the second alternative). As another example, the DRS in the first subframe can follow one of the above proposed structures (e.g., the second alternative), while the DRS in a next subframe can follow a different proposed structure (e.g., the third alternative).

[0046] In one example, for DRS transmission, various designs can be implemented for systems adopting LBT and/or frequency hopping. For example, in a system where LBT is used as the basic method for coexistence, LBT can be applied before the DRS transmission. The LBT duration and sensitivity can be further studied based on different regulation specifications. In another example, single-shot LBT can be performed. In another example, when frequency hopping is used for coexistence, the DRS can be transmitted on one or multiple anchor channels. Within one anchor channel during a dwell time, the DRS can be sent periodically with a fixed periodicity (e.g. 5ms).

[0047] In one configuration, with respect to a DRS physical channel design, a DRS structure can be designed for U-IoT, where the DRS can span over one or multiple subframes. The DRS in one subframe within the DRS duration can have a structure in accordance with one of the following three alternatives.

[0048] In a first alternative, the DRS in one subframe can consist of

PSS/SSS/CRS/PBCH, where the PSS/SSS can follow legacy LTE. In the first alternative, the PSS/SSS can be the same as the PSS/SSS in LAA DRS, e.g., the PSS presents at symbol 6 and the SSS presents at symbol 5. The CRS can be the same as the CRS in Rel- 12 DRS. In addition, a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13} .

[0049] FIGS. 3A and 3B illustrate an example of a discovery reference signal (DRS) structure in a first alternative. As shown in FIG. 3A, a PBCH can be transmitted on symbols {2, 3, 4, 7, 8, 9, 10, 11, 12, 13}. As shown in FIG. 3B, a PBCH can be transmitted additionally on symbols 0 and 1. [0050] In a second alternative, the DRS in one subframe can consist of PSS/SSS/CRS/PBCH, where additional PSS/SSS can be present in symbols 2 and/or 3. In the second alternative, in addition to the PSS/SSS which are the same as the PSS/SSS in LAA DRS (e.g., PSS at symbol 6 and SSS at symbol 5), additional PSS/SSS can be added to symbol 2 and/or 3. The CRS can be the same as the CRS in Rel-12 DRS. In addition, a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0,

1, 4, 11, 12, 13} if symbols 2 and 3 are used for additional PSS/SSS, or {7, 8, 9, 10, 0, 1,

2, 4, 11, 12, 13} if symbol 3 is used for additional PSS/SSS, or {7, 8, 9, 10, 0, 1, 3, 4, 11, 12, 13} if symbol 2 is used for additional PSS/SSS.

[0051] FIGS. 4A and 4B illustrate an example of a discovery reference signal (DRS) structure in a second alternative. In the second alternative, symbols 0 and 1 may or may not carry a PBCH, depending on if a physical downlink control channel (PDCCH) is transmitted on a central 6 physical resource blocks (PRBs). As shown in FIG. 4A, symbols 0 and 1 do not carry the PBCH, and as shown in FIG. 4B, symbols 0 and 1 do carry the PBCH.

[0052] In one example, the additional PSS/SSS can be the same as the legacy PSS/SSS, or can be different. In another example, the DRS can be the same as the DRS in MulteFire 1.0, as shown in FIG. 2.

[0053] In one example, the DRS in one subframe can consist of the legacy PSS and SSS in symbols 3 and 2, respectively, and additional PSS and SSS (e.g., MF-PSS and MF-

SSS) in symbols 6 and 5, respectively. In other words, the PSS and MF-PSS, and SSS and MF-SSS can be switched.

[0054] FIG. 5 illustrates an example of a discovery reference signal (DRS) structure in a second alternative. In the second alternative, symbols 0 and 1 may or may not carry a PBCH, depending on if PDCCH is transmitted on a central 6 PRBs. In the example shown in FIG. 5, symbols 0 and 1 do not carry the PBCH. In addition, the PSS and MF- PSS, SSS and MF-SSS can be switched, as compared to the DRS in MF 1.0. In one example, this DRS structure can enable the UE to differentiate which subframe is a first repetition of a DRS subframe, in cases where the DRS spans over multiple subframes and there are at least 2 subframes that contain the PSS/SSS and additional PSS/SSS.

[0055] In one example, the DRS can consist of the PSS/SSS in symbol 3/2 and no legacy PSS/SSS in symbol 6/5. The PSS/SSS in symbol 3/2 can be the same as the legacy PSS/SSS or different (e.g., same as MF-PSS/MF-SSS in MulteFire 1.0).

[0056] In a third alternative, the DRS in one subframe can consist of the CRS/PBCH, and no PSS/SSS can be present. In the third alternative, the DRS on the considered subframe can consist of the CRS/PBCH, where the CRS is the same as the CRS in Rel-12 DRS. No PSS/SSS can be present in this subframe. In addition, a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 11, 12, 13} .

[0057] FIGS. 6A and 6B illustrate an example of a discovery reference signal (DRS) structure in a third alternative. In the third alternative, symbols 0 and 1 may or may not carry a PBCH, depending on if a PDCCH is transmitted on a central 6 PRBs. As shown in FIG. 6A, symbols 0 and 1 do not carry the PBCH, and as shown in FIG. 6B, symbols 0 and 1 do carry the PBCH.

[0058] In one configuration, with respect to a MIB transmission in additional symbols, when the MIB is transmitted over symbols in addition to symbols 7, 8, 9, and 10 for all of the above three alternatives, various techniques to carry the MIB can be considered.

[0059] FIG. 7 illustrates an example of a discovery reference signal (DRS) structure in which physical broadcast channel (PBCH) signals are repeated. In this example, the PBCH symbols can be repeated, similar as in Rel-13 eMTC. For example, similar to the PBCH in FDD Rel-13 eMTC systems, symbols 7, 8, 9 and 10 can be repeated in symbols 4, 11, 12, and 13, respectively. In one example, the CRS in symbols 7 and 8 can be copied together when these two symbols are repeated. In another example, the CRS may not be copied when symbols 7 and 8 are repeated. The REs which carry the CRS in these two symbols can be left empty in repeated symbols, or can be used to transmit the MIB.

[0060] FIG. 8 illustrates an example of a discovery reference signal (DRS) structure in which a master information block (MIB) is rate matched to more symbols. In this example, the MIB can be rate matched to additional symbols, similar to the DRS in MulteFire 1.0.

[0061] In one example, the DRS can span over multiple subframes. When the DRS has a duration of more than one subframe, any combinations of the above proposed designs in different subframes can be considered. [0062] FIG. 9 illustrates an example of a discovery reference signal (DRS) design in which the DRS occupies multiple subframes. For example, the DRS can be repeated over multiple subframes, where the DRS in one subframe can follow one of the three DRS structure alternatives, as described above. As shown in FIG. 9, the DRS can occupy 2 subframes, which can have the same DRS structure (e.g., the DRS structure in the second alternative, as discussed above), and a MIB can be rate matched to the symbols carrying the MIB.

[0063] FIGS. 10A and 10B illustrate an example of a discovery reference signal (DRS) design in which the DRS occupies multiple subframes. The DRS can be repeated over multiple subframes, where the DRS in each subframe can follow one of the three DRS structure alternatives, as described above. For example, the DRS can occupy 2 subframes, which can have different DRS. In addition, the symbols carrying the MIB can be repeated, or the MIB can be rate matched on these symbols.

[0064] As shown in FIGS. 10A and 10B, a DRS is a first subframe can follow one of the three DRS structure alternatives, as described above, while a DRS in a next subframe can follow a different DRS structure alternative (as compared to the DRS in the first subframe). As shown in FIGS. 10A and 10B, the DRS in the first subframe can be based on the DRS structure in the second alternative, while the DRS in the next subframe can be based on the DRS structure in the third alternative. In addition, as shown in FIG. 10A, symbols 0 and 1 do not carry the PBCH, and as shown in FIG. 10B, symbols 0 and 1 do cany the PBCH.

[0065] FIGS. 11A, 11B, 11C and 11D illustrate examples of a discovery reference signal (DRS) design in which the DRS occupies multiple subframes. In these examples, the DRS can occupy 2 subframes, which can have different structures (e.g., different PSS/SSS locations). In one example, the symbols carrying a MIB can be repeated, or the MIB can be rate matched on these symbols. Different PSS/SSS structures in different DRS repetitions can help to differentiate a number of DRS repetitions, and avoid confusion on the subframe index. In addition, the first n symbols may carry or may not carry the MIB, depending on if PDCCH is transmitted in these symbols, where n can be 0, 1, 2, 3.

[0066] In one example, as shown in FIGS. 11 A to 11D, the PSS and MF-PSS, SSS and MF-SSS can be switched in 2nd repetitions, or only 1 repetition can contain two PSS and two SSS symbols. In this example, the UE can perform blind detection, and based on the PSS/SSS structure, the UE can determine a particular repetition of a current received DRS subframe. In addition, the UE can determine a subframe index based on a subframe index indication carried in the MIB plus a number of repetitions minus one.

[0067] In one example, the DRS following the designs described above can be repeated N times, e.g., N=2. For example, a DRS occupying 2 subframes can be repeated twice (i.e., in total the DRS can span 4 subframes).

[0068] In one example, a scrambling and/or CRS sequences in DRS subframes can depend on the subframe index. Alternatively, the scrambling and/or CRS sequences in DRS subframes can be the same across repeated DRS subframes, depending on the 1st repetition of the DRS or based on a predefined rule.

[0069] In one example, a unicast physical downlink shared channel (PDSCH) may not be multiplexed in the DRS subframe. Alternatively, the unicast PDSCH and the DRS can be multiplexed in a certain subframe, e.g., when the scrambling sequence and/or CRS sequence used in the DRS is a same as legacy scrambling and/or CRS sequences in that subframe (e.g., subframe 0/5).

[0070] In one configuration, in a system where LBT is used for coexistence, LBT can be applied before a DRS transmission. The LBT duration and sensitivity can be further studied based on different regulation specifications. In another example, single-shot LBT can be performed.

[0071] In one configuration, with respect to a DRS transmission in a frequency hopping system (e.g., when frequency hopping is used for coexistence), the DRS can be transmitted on one or multiple anchor channels. Within one anchor channel during a dwell time, the DRS can be sent periodically with a fixed periodicity (e.g., 5ms). A hopping pattern can be derived from a physical cell identity (PCI) that is carried by the PSS/SSS, or from a system information block for MulteFire (SIB-MF), which can be scheduled by the MIB-MF. The UE will listen to the anchor channel during an initial access procedure.

[0072] In one configuration, a DRS design for unlicensed-IoT (U-IoT) and/or wideband coverage enhancement is described. The DRS can consist of PSS/SSS/CRS/PBCH, and can span over one or multiple subframes.

[0073] In one example, the DRS in one subframe can consist of PSS/SSS/CRS/PBCH, where: the PSS presents at symbol 6, the SSS presents at symbol 5, the CRS can be the same as the CRS in Rel-12 DRS, which presents in symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13}.

[0074] In one example, the DRS in one subframe can consist of PSS/SSS/CRS/PBCH, where: the PSS presents at symbol 6, the SSS presents at symbol 5, additional PSS/SSS can be present at symbols 2 and/or 3, which can be the same as the legacy PSS/SSS or different, the CRS is the same as the CRS in Rel-12 DRS, which presents in symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, and a MIB can be transmitted in one or multiple OFDM symbols which are not used for PSS/SSS within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13}.

[0075] In one example, the DRS can be the same as the DRS in MulteFire 1.0, where: a PSS presents at symbol 6, a SSS presents at symbol 5, additional PSS and SSS present at symbol 3 and 2, respectively, which can be the same as the legacy PSS/SSS or different, a CRS is the same as the CRS in Rel-12 DRS, which presents in symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, and a MIB can be transmitted in one or multiple OFDM symbols which are not used for PSS/SSS within the set {7, 8, 9, 10, 4, 11 }.

[0076] In one example, the PSS and SSS in symbol 6 and 5, respectively, can be the same as the legacy PSS and SSS.

[0077] In one example, the DRS in one subframe can consist of PSS/SSS/CRS/PBCH, where: the PSS presents at symbol 3, which can be the same as the legacy PSS or different (e.g., the same as MF-PSS in MulteFire 1.0), the SSS presents at symbol 2, which can be the same as the legacy SSS or different (e.g. the same as MF-SSS in

MulteFire 1.1), and additional PSS/SSS which may or may not be present at symbols 5 and/or 6. For example, if the PSS/SSS presents at symbols 5 and/or 6, the PSS/SSS can be different from the legacy PSS/SSS (e.g., the same as MF-PSS/MF-SSS in MulteFire 1.1). In addition, the CRS can be the same as the CRS in Rel-12 DRS, which presents in symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, and a MIB can be transmitted in one or multiple OFDM symbols which are not used for PSS/SSS within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13} .

[0078] In one example, the DRS in one subframe can consist of CRS/PBCH without PSS/SSS, where: the CRS is the same as the CRS in Rel-12 DRS, which presents in symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 2, 3, 4, 5, 6, 12, 13}.

[0079] In one example, when the MIB is transmitted over more than 4 symbols, i.e., symbols other than 7, 8, 9, and 10, the PBCH symbols on symbols 7, 8, 9, and 10 can be repeated in additional symbols, e.g., one of multiple symbols within set {7, 8, 9, 10} can be repeated once or multiple times on symbols within the set {0, 1, 2, 3, 4, 5, 6, 11, 12, 13} .

[0080] In one example, the CRS in symbols 7 and 8 can be copied along with other REs in symbols 7 and 8 when they are repeated. In another example, the CRS in symbols 7 and 8 is not copied along with other REs in symbols 7 and 8 when they are repeated, e.g., the REs carrying CRS may be left empty or be used for a MIB transmission.

[0081] In one example, when a MIB is transmitted over more than 4 symbols, i.e., symbols other than 7, 8, 9, and 10, the MIB can be rate matched to all the symbols carrying the MIB.

[0082] In one example, the DRS can span over multiple subframes, and each of the subframes can have the same structure.

[0083] In one example, the DRS on each subframe can have the following structure: one PSS presents at symbol 6, and an additional PSS presents at symbol 3, one SSS presents at symbol 5, and an additional SSS presents at symbol 2, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g. in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13} .

[0084] In one example, the DRS can span over multiple subframes, and some of the subframes can have different structures.

[0085] In one example, the DRS on some subframes can have the following structure: one PSS presents at symbol 6, and an additional PSS presents at symbol 3, one SSS presents at symbol 5, and an additional SSS presents at symbol 2, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g. in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13}, and the DRS on other subframes can have the following structure: a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g. in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 11, 12, 13}.

[0086] In one example, the DRS on some subframes can have the following structure: one PSS (same as legacy PSS) presents at symbol 6, and an additional PSS (different from legacy PSS, e.g.. same as MF-PSS in MulteFire 1.0) presents at symbol 3, one SSS (same as legacy SSS) presents at symbol 5, and an additional SSS presents (different from legacy SSS, e.g.. same as MF-SSS in MulteFire 1.0) at symbol 2, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g., in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13}, and the DRS on other subframes can have the following structure: one PSS (different from legacy PSS, e.g., same as MF-PSS in MulteFire 1.0) presents at symbol 6, and an additional PSS (same as legacy PSS) presents at symbol 3, one SSS (different from legacy SSS, e.g., same as MF-SSS in MulteFire 1.0) presents at symbol 5, and an additional SSS (same as legacy SSS) presents at symbol 2, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g., in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13} .

[0087] In one example, the DRS on some subframes can have the following structure: one PSS (same as legacy PSS) presents at symbol 6, and an additional PSS (different from legacy PSS, e.g., same as MF-PSS in MulteFire 1.0) presents at symbol 3, one SSS (same as legacy SSS) presents at symbol 5, and an additional SSS presents (different from legacy SSS, e.g., same as MF-SSS in MulteFire 1.0) at symbol 2, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g., in Rel-12 DRS), a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13}, and the DRS on other subframes can have the following structure: one PSS (different from legacy PSS, e.g., same as MF-PSS in MulteFire 1.0) presents at symbol 3, one SSS (different from legacy SSS, e.g. same as MF-SSS in MulteFire 1.0) presents at symbol 2, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as CRS in legacy LTE (e.g., in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13},

[0088] In one example, the DRS on some subframes can have the following structure: one PSS (same as legacy PSS) presents at symbol 6, and an additional PSS (different from legacy PSS, e.g., same as MF-PSS in MulteFire 1.0) presents at symbol 3, one SSS (same as legacy SSS) presents at symbol 5, and an additional SSS presents (different from legacy SSS, e.g., same as MF-SSS in MulteFire 1.0) at symbol 2, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g. in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13}, and the DRS on other subframes can have the following structure: one PSS (same as legacy PSS) presents at symbol 6, one SSS (same as legacy SSS) presents at symbol 5, a CRS presents at symbols 0, 1, 4, 7, 8 and/or 11 depending on CRS ports, same as the CRS in legacy LTE (e.g., in Rel-12 DRS), and a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 11, 0, 1, 4, 12, 13},

[0089] In one example, the DRS can be transmitted after one shot LBT when LBT is used as for coexistence. In another example, the DRS can be transmitted over one or multiple anchor channels when frequency hopping is used. In yet another example, the DRS can be transmitted periodically on an anchor channel, e.g., during allowed dwell time only.

[0090] In one example, the first n symbols in DRS subframe(s) can carry a MIB or may not carry the MIB, depending on if PDCCH is transmitted on these symbols, where n can be 0, 1, 2, 3 and can be configured via a control format indicator (CFI). In another example, a scrambling sequence and/or CRS sequences can be the same across repeated DRS subframes, e.g., depending on a 1st repetition of DRS. In yet another example, the scrambling sequence and/or CRS sequences can be subframe dependent, and may be different across DRS repetitions.

[0091] In one example, a unicast PDSCH and DRS cannot be multiplexed. In another example, the unicast PDSCH and DRS can be multiplexed in a certain subframe, e.g., when the scrambling sequence and/or CRS sequences used in DRS are the same as the legacy scrambling and/or CRS sequences in that subframe (e.g. subframe 0/5).

Design of Discovery Reference Signals for Wideband Coverage Enhancement (WCE)

[0092] The present technology relates to LTE operation in the unlicensed spectrum in MulteFire, and specifically to the wideband coverage enhancement (WCE) for MulteFire. For example, a novel discovery reference signal (DRS) design can be applied for WCE and/or eMTC based U-IoT systems.

[0093] In one example, 3GPP has standardized two designs to support IoT services - eMTC and NB-IoT. In summary, eMTC and NB-IoT techniques are designed to ensure that the UEs have low cost, low power consumption and enhanced coverage. To extend the benefits of LTE IoT designs into unlicensed spectrum, MulteFire 1.1 is expected to specify the design for Unlicensed-IoT (U-IoT) based on eMTC and/or NB-IoT. The unlicensed frequency band of current interest for NB-IoT or eMTC based U-IoT is the sub-1 GHz band and the ~2.4GHz band. In addition, different from eMTC and NB-IoT which applies to narrowband operation, WCE is also of interest to MulteFire 1.1 with an operation bandwidth of 10MHz and 20MHz. The objective of WCE is to extend the MulteFire 1.0 coverage to meet industry IoT market specifications, with the targeting operating bands at 3.5GHz and 5GHz.

[0094] In one example, with respect to regulations in the unlicensed spectrum, MulteFire 1.0 operations can occur on the unlicensed frequency band of 3.5GHz and 5GHz, which has wide spectrum with global common availability. The 5 GHz band in the US is governed by Unlicensed National Information Infrastructure (U-NII) rules by the Federal Communications Commission (FCC). The main incumbent system in the 5 GHz band is the Wireless Local Area Networks (WLAN), specifically those based on the IEEE 802.11 a/n/ac technologies. Since WLAN systems are widely deployed both by individuals and operators for carrier-grade access service and data offloading, sufficient care is to be taken before deployment. Therefore, Listen-Before-Talk (LBT) is considered a mandatory feature of the Rel-13 LAA system and MulteFire 1.0 for fair coexistence with the incumbent system. LBT is a procedure whereby radio transmitters first sense the medium and transmit only if the medium is sensed to be idle.

[0095] On the other hand, for the unlicensed sub-1 GHz band and the ~2.4GHz band, the regulations are different for different regions, e.g., in aspects such as different maximal channel bandwidth, LBT, duty cycling, frequency hopping and power limitations may be necessitated. For example, in Europe, it is necessary to have either LBT or <0.1% duty cycle for frequency hopping spread spectrum (FHSS) modulation with channel bandwidth no less than 100kHz within 863-870MHz, and for digital modulation with channel bandwidth no greater than 100kHz within 863-870MHz. Either LBT and/or frequency hopping can be used for coexistence with other unlicensed band transmissions.

[0096] In one configuration, the DRS design for WCE and/or eMTC based U-IoT in

MulteFire 1.1 is defined in greater detail below, considering both the aspects of coverage enhancement (CE) and LBT impact. In the DRS design for MulteFire CE, a DRS can span over one or multiple subframes. In a fourth altemative, the DRS can be continuously transmitted in multiple N subframes, e.g., N=2, 3 or 4, with LBT performed only before a first DRS subframe. In a fifth altemative, the DRS can be transmitted in N subframes, with a certain number of symbols punctured among the subframes for a LBT gap. For example, single-interval LBT can be performed before each DRS subframe, and each DRS subframe can occupy 12 OFDM symbols. In another example, category 4 (Cat-4) LBT with priority 1 can be performed before every 2 DRS subframes, where the last M symbols of every 2 subframes can be punctured for the LBT gap, where M can be 1 or 2. In addition, details on the DRS physical structure, MIB transmission techniques, and SIB- MF transmission techniques are discussed in further detail below.

[0097] In one configuration, with respect to a DRS transmission technique, a DRS design for MulteFire CE is defined, where DRS may spans over one or multiple subframes. The DRS design can be in accordance with one of the following three alternatives.

[0098] In a fourth alternative, the DRS can be continuously transmitted in multiple N subframes, e.g., N=2, 3 or 4, with LBT performed only before a first DRS subframe. For example, in the fourth alternative, various LBT techniques can be adopted for the DRS transmission in accordance with the first alternative. In one example, N = 1 and a number of symbols occupied by the DRS subframe can be no more than 12. In this example, single-interval LBT can be performed for the DRS transmission. In another example, N is no larger than 2, and then Cat-4 LBT with priority 1 can be performed for the DRS transmission. In another example, for N no larger than 3, Cat-4 LBT with priority 2 can be performed for the DRS transmission. In yet another example, when N>3, Cat-4 LBT with priority 3 or 4 can be performed for the DRS transmission.

[0099] FIGS. 12A and 12B illustrate an example of a discovery reference signal (DRS) structure in a fourth alternative. As shown, LBT can be performed before a system frame number (SFN) for a DRS transmission. As shown in FIG. 12A, N = 3, and as shown in FIG. 12B, N = 4.

[00100] In a fifth alternative, the DRS can be transmitted in multiple N subframes, with a certain number of symbols punctured between these subframes. The punctured symbols can be used for a LBT gap. In other words, an eNodeB can perform multiple LBTs during the DRS transmission. In one example, LBT can be performed before each DRS subframe, as shown in FIG. 13 below. In case each DRS subframe occupies up to 12 symbols, single-interval LBT can be performed for each DRS subframe. In one example, symbols 0 and 1 in subframes n+1, n+2 and n+3 can be used for PBCH if no PDCCH is to be transmitted. Alternatively, symbols 0 and 1 in each DRS subframe can be used for a PDCCH transmission.

[00101] FIG. 13 illustrates an example of a discovery reference signal (DRS) structure in a fifth alternative. For example, in the fifth alternative, single-interval LBT can be performed before each DRS subframe. In this example, symbols 0 and 1 in all DRS subframes are not used for PBCH, as they can be used for a PDCCH transmission.

Alternatively, symbols 0 and 1 in DRS subframes other than the first one can be used for a PBCH transmission, if the PDCCH is not to be transmitted in these subframes.

[00102] In one example, LBT can be performed every M DRS subframes. In case M is no more than 2, e.g., M=2, then Cat-4 LBT with priority 1 can be performed for every 2 DRS subframes, as shown in FIG. 14 below. The last 1 or 2 symbols of every M subframes can be left blank for a LBT gap. In one example, with Cat-4 LBT with priority 1, a contention window size (CWS) can be 3 or 7. With CWS of 3, a shortest duration for LBT is 25us + 3 * 9us = 52us, which is smaller than 1 symbol. Thus, 1 symbol can be left blank for this case. Alternatively, 2 symbols can be left blank to allow the eNodeB to have additional chances for LBT. However, without a reservation signal, the 2-symbol gap can result in a larger blocking rate, since other transmitters can grab the channel within this 2- symbol duration with an increased probability. If the reservation signal is used, a last symbol can be left blank due to a maximum channel occupancy time (MCOT) limit which takes into account the reservation signal duration. Further, in case M = 3, then Cat-4 LBT with priority 2 can be performed. Alternatively, when M=4, then Cat-4 LBT with priority 3 or 4 can be performed for DRS transmission.

[00103] FIG. 14 illustrates an example of a discovery reference signal (DRS) structure in a fifth alternative. For example, in this variation of the fifth alternative, Cat-4 LBT can be performed before every 2 DRS subframes. In this example, symbols 0 and 1 in every 2 DRS subframes are not used for PBCH, as they are used for a PDCCH transmission.

Alternatively, symbols 0 and 1 in DRS subframes other than the first one can be used for PBCH transmission, if the PDCCH is not to be transmitted in these subframes. In addition, the last 1 symbol of the SF n+1 can be left blank for a LBT gap.

[00104] In an alternative example, single-interval LBT can performed for a first DRS subframe, and Cat-4 LBT can be performed for following N-l DRS subframes, as shown in FIG. 15 below. A Cat-4 LBT priority can depend on a number of following DRS subframes to be transmitted. For example, if there are 2 DRS subframes to be transmitted after the 1st DRS subframe, then Cat-4 LBT with priority 1 can be used. Otherwise, Cat-4 LBT with priority 2 and Cat-4 LBT with priority 3 or 4 can be used for 3-DRS-subframe transmission and 4-DRS -subframe transmission, respectively. In addition, the last 2 symbols of the 1st DRS subframe can be used for the Cat-4 LBT.

[00105] FIG. 15 illustrates an example of a discovery reference signal (DRS) structure in a fifth alternative. For example, in this further variation of the fifth alternative, single- interval LBT can be performed for a first DRS subframe, and Cat-4 LBT can be performed for the following DRS subframes. In this example, symbols 0 and 1 in 2nd DRS subframes are not used for PBCH, as they are used for a PDCCH transmission. Alternatively, symbols 0 and 1 in DRS subframes other than the first one can be used for a PBCH transmission, if the PDCCH is not to be transmitted in these subframes. In addition, the last 2 symbols of the 1st DRS subframe can be used for LBT.

[00106] In one example, if the DRS transmission is within a transmission opportunity (TxOP), the Cat-4 LBT in the above examples can be replaced by single shot LBT. [00107] In one example, the fourth alternative as described above (i.e., continuous N DRS subframes) can be used if the DRS transmission is within a TxOP, and the fifth alternative as described above (e.g., two sets with each set consisting of two DRS subframes, and the last symbol of the first set left blank) can be used if the DRS transmission is outside a TxOP. The UE's behavior in this transmission technique can vary accordingly. For example, the UE can perform rate matching around a last symbol, i.e., the UE assumes that the last symbol is not used for a PBCH transmission, which can result in performance loss as the UE does not exploit the last symbol containing the MIB. In another example, the UE performs 2 hypothesis tests. For example, the UE can perform two hypothesis tests for cases with and without the last symbol, which can be left blank. In another example, the UE can perform two hypothesis tests for cases with different PSS/SSS/MF-PSS/MF-SSS sequences based on an option for DRS physical structure design with respect to PSS/SSS, as described below. In yet another example, the UE can perform two hypothesis tests for cases with different CRS sequences based on an option for DRS physical structure design with respect to CRS, as described below.

[00108] In one example, when the fifth alternative as described above (or a sixth altemative as described below) is used for both within and outside TxOP, LBT is possibly not performed between DRS subframes for cases within TxOP, and the eNodeB can transmit a PBCH or other reservation signals in symbols left blank in these alternatives.

[00109] In a sixth alternative, the DRS can be transmitted over 2 subsequent subframes, and can span over 12 resource blocks (RBs) in the frequency domain. While the designs described above involve a DRS that spans over 6 RBs, in this sixth alternative, the DRS can span over 12 RBs, which can be continuous or distributed in the frequency domain. In one example, a legacy DRS can be positioned in the central RBs of the first subframe, while the other RBs in that subframe can contain an additional DRS. In one example, the first or last 6 RBs of the total allocated RBs, can be devoted to the legacy DRS. In another example, the legacy DRS can start after an offset of K RBs.

[00110] In one example, regardless of which RBs are devoted to legacy DRS, the first set of 6 RBs can be indicated as Rl and the second set of RBs can be indicated as R2.

[00111] In one example, remaining PRBs, which are not used by the legacy DRS, can be used for a repeated version of the legacy DRS. In another example, the 12 RBs can all contain the legacy DRS. In order to avoid confusion, in one example, the repeated DRS can be characterized by PSS/MF-PSS/SSS/MF-SSS whose locations are swapped, as compared to a legacy structure. In one example, different sequences can be used for PSS/MF-PSS/SSS/MF-SSS, as compared to the legacy DRS.

[00112] In one example, the DRS can be stretched in the frequency domain over 12 RBs, and also repeated in time over 2 subframes: subframe "n" and subframe "n+1". The repetitions of the DRS over the subframe "n+1" can be specular to the DRS structure in the subframe "n". In one example, in order to avoid confusion, the position of the PSS/SSS and MF-PSS/MF-SSS can be swapped, as compared to the previous subframe and equivalent RB. In an alternative, a structure of the repeated DRS over the additional RBs in the first subframe can be maintained in the second subframe. In another example, while the RBs for subframe "n" can be used for legacy DRS, the RBs for subframe "n+1" can follow a different partem, in which the PSS/MF-PSS/SSS/MF-SSS are swapped, or by containing different sequences. In another example, in subframe "n" the RBs can be used for legacy DRS, in subframe "n+1" Rl and R2 can contain a DRS with a different structure (e.g., swapped synchronization signals) or different sequences between each other. In another example, a structure of the set of RBs Rl in subframe "n" can be repeated in the set of RBs R2 of subframe "n+1", and a structure of the set of RBs R2 in subframe "n" can be repeated in the set of RBs Rl of subframe "n+1".

[00113] FIG. 16 illustrates an example of two discovery reference signals (DRS) over resource blocks (RBs) in a frequency domain. For example, 2 DRS can be over 12 (consecutive) RBs in the frequency domain. As shown, a first set of 6 RBs can be indicated as Rl, and can represent a first DRS, and a second set of RBs can be indicated as R2, and can represent a second DRS. In a first case, the first DRS can occupy the first 6 RBs, and the second DRS can occupy the last 6 RBs. In a second case, the second DRS can occupy the central RBs, and the first DRS can occupy RBs surrounding the central RBs. In a third case, the second DRS can occupy 6 consecutive RBs, while the first DRS can occupy the first K RBs and the last 12-6-K RBs.

[00114] In one example, the DRSs stretched over the 12 RBS and two consecutive subframes can be jointly decoded.

[00115] In one example, the DRS can be transmitted over two consequential subframes and span over 12 RBS. In one example, Cat-4 LBT with priority 1 can be performed for the DRS transmission. Similarly as above, in another example, LBT can be performed before each DRS subframe. In case each DRS subframe occupies up to 12 symbols, single-interval LBT can be performed for each DRS subframe. In addition, symbols 0 and 1 in subframes n, n+1 can be used for the PBCH if no PDCCH is to be transmitted.

[00116] FIG. 17 illustrates an example of a discovery reference signal (DRS) structure in which single-interval listen before talk (LBT) is performed before each DRS subframe. In one example, the DRS can span over 12 RBs, and a first 6 RBs of subframe n can be used to transmit a legacy DRS, while remaining RBs can be used to transmit its swapped version. The replica in time over subframe n+1 is a swapped version of DRS structure for subframe n. In another example, LBT can be performed before a first DRS subframe. In addition, symbols 0 and 1 in the second DRS subframes may not be used for PBCH, as they are used for a PDCCH transmission. Alternatively, symbols 0 and 1 in the second DRS subframe can be used for a PBCH transmission, if the PDCCH is not to be transmitted in these subframes.

[00117] In one configuration, a DRS in a subframe can be in accordance with a DRS physical structure, as described below. For example, each DRS subframe can consist of PSS/SSS/CRS/PBCH/SIB-MF. The PSS/SSS and MF-PSS/MF-SSS can be the same as the PSS/SSS and MF-PSS/MF-SSS in DRS of MulteFire 1.0, at least in the first DRS subframe. Considering backward compatibility, the following second and third options can be preferred, as the different PSS/SSS structure can help the legacy MF 1.0 UE differentiate the legacy DRS subframe and additional DRS subframes, and thus determine the subframe index. In a first option, the PSS/SSS and MF-PSS/MF-SSS can be the same across all DRS subframes. In a second option, the DRS subframes except a first DRS subframe can have PSS and MF-PSS switched, and/or SSS and MF-SSS switched, compared to DRS in MulteFire 1.0. In a third option, the PSS/SSS in a DRS subframe other than the 1st DRS subframe can be different from the legacy PSS/SSS. The MF-PSS and/or MF-SSS can be used, or a new PSS and/or SSS that are different from the LTE PSS/SSS and MF-PSS/MF-SSS can be used. Alternatively, new sequences can be used for the MF-PSS/MF-SSS for DRS subframes other than the 1st DRS subframe. In a fourth option, in addition to changes made based on the second and third options, the PSS/SSS/MF-PSS/MF-SSS sequence in the last subframe of a TxOP, where the last symbol of the subframe is left blank, can be different from a 1st DRS subframe and other DRS subframes. The UE can detect if the last symbol is left blank based on the detection of different PSS/SSS/MF-PSS/MF-SSS sequences.

[00118] In one example, with respect to the DRS physical structure, the CRS can be defined as follows. For example, in a first option, the CRS can be the same as the CRS in Rel-12 DRS. In a second option, a different CRS sequence can be used for the DRS subframe where the last symbol is left blank. For example, a phase rotation (e.g., -1) can be applied to at least one of the CRS symbols in the DRS subframe with the last symbol left blank. In another example, with respect to the DRS physical structure, a MIB can be transmitted in one or multiple OFDM symbols within the set {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13}, and a SIB-MF can be transmitted on DRS subframes outside of the central 6 PRBs.

[00119] In one example, with respect to a MIB rate matching and repetition technique, when the MIB is transmitted over symbols in addition to symbols 7, 8, 9, and 10, various techniques to carry the MIB can be considered. For example, the PBCH symbols can be repeated, similar to Rel-13 eMTC. For this case, a symbol-level combining of PBCH can be used. In another example, the MIB can be rate matched to these symbols, similar to DRS in MulteFire 1.0. For this case, a soft-bit combining of PBCH can be used. In another example, the content of PBCH can be repeatedly transmitted, including the subframe offset. In this example, the subframe offset can indicate the subframe offset between the first DRS subframe and the subframe #0/#5.

[00120] In one example, with respect to a SIB-MF transmission technique, a SIB-MF can be transmitted on DRS subframes, outside of the central 6 PRBs. The PDCCH can be used to schedule the SIB-MF. In one example, a PDCCH scheduling SIB-MF can be transmitted only in the first DRS subframe. In this case, if the DRS transmission method follows the fifth alternative as discussed above, where LBT is performed for DRS subframes other than 1st DRS subframe, the UE can first detect a presence of DRS for these DRS subframes other than the first DRS subframe before which LBT is performed, and then the UE can conduct the SIB-MF detection. In one example, if the LBT for the first DRS subframe transmission fails, the following DRS subframes within this DRS period would not be transmitted either, since no scheduling information for SIB-MF is available.

[00121] In one example, a PDCCH scheduling SIB-MF can be transmitted in the DRS subframe before which LBT is performed. In this case, by detecting the PDCCH, the UE can know the presence of the SIB-MF, and the UE can perform SIB-MF detection correspondingly, e.g., with symbol level or soft bits combining. In an alternative example, a PDCCH scheduling SIB-MF can be transmitted in every DRS subframe. In this case, by detecting the PDCCH, the UE can know the transmission of the SIB-MF and can perform SIB-MF detection correspondingly. However, since SIB-MF scheduling information, such as a PRB allocation and a modulation and coding scheme (MCS), is not expected to be changed across these DRS subframes, UE power consumption would be increased if the UE monitors the PDCCH in every DRS subframe.

[00122] In one configuration, a DRS design for wideband coverage enhancement is described. In one example, the DRS can be transmitted in multiple N subframes, e.g. N=2, 3 or 4. In another example, only one LBT can be performed before a first DRS subframe. In yet another example, single-interval LBT can be performed if N=l and DRS occupies up to 12 symbols, or if the DRS transmission is within TxOP, or Cat-4 LBT with priority 1, 2, and 3 or 4 can be performed for N<=2, N=3 and N=4 for DRS outside TxOP, respectively.

[00123] In one example, the DRS can be transmitted in multiple N subframes, with a certain number of symbols punctured/left blank between these subframes. In another example, the symbols punctured/left blank can be used for a LBT gap. In yet another example, LBT is performed before each DRS subframe. In a further example, LBT can be performed every M DRS subframes, e.g., M=2. In yet a further example, LBT can be performed in first DRS subframes according to a LBT technique in MF 1.0 for DRS subframe, and another LBT can be performed for following DRS subframes.

[00124] In one example, the DRS can be transmitted in continuous N subframes if they are within a TxOP, while DRS N subframes are separately into multiple sets with LBT performed before each set if the DRS transmission is outside TxOP. In another example, two LBTs can be performed for two sets of DRS subframes, respectively, with the last symbol of a first set being blank for a LBT gap. In yet another example, a same DRS transmission technique can be used for both within TxOP and outside TxOP, with a possible difference in the LBT technique.

[00125] In one example, the DRS can consist of PSS/SSS/CRS/PBCH/SIB-MF, and can span over one or multiple subframes. In one example, the PSS/SSS and MF-PSS/MF- SSS can be the same (including sequence and locations) across all DRS subframes, which is the same as the DRS in MF 1.0. In another example, PSS and MF-PSS locations can be switched, and/or SSS and MF-SSS locations can be switched in DRS subframes except a 1st DRS subframe. In yet another example, the PSS/SSS in DRS subframes other than the first DRS subframe can be different from the legacy PSS/SSS, e.g., the MF-PSS/MF- SSS can be used or a new PSS/SSS sequence can be used with a new root index. In a further example, the MF-PSS/MF-SSS in DRS subframes other than the first DRS subframe can be different from the legacy MF-PSS/MF-SSS, e.g., the PSS/SSS can be used or a new PSS/SSS sequence can be used with a new root index. In yet a further example, the PSS/SSS/MF-PSS/MF-SSS in the last subframe of a TxOP where the last symbol is punctured/left blank, can be different from other DRS subframes, e.g., by introducing new PSS/SSS sequences.

[00126] In one example, the CRS can be same as the Rel-12 CRS and can be the same across all DRS subframes. In another example, different CRS sequences can be used for at least one CRS symbol in a DRS subframe with a last symbol punctured/left blank. In yet another example, a different phase can be applied to a Rel-12 CRS to generate a different CRS sequence, e.g., multiplied by -1 for CRS symbols. In a further example, a MIB can be transmitted in one or multiple OFDM symbols within set {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13}. In yet a further example, a SIB-MF can be transmitted in a DRS subframe outside of a central 6 PRBs.

[00127] In one example, PBCH symbols can be repeated, similar to Rel-13 eMTC, or can be rate matched. In another example, a PDCCH scheduling SIB-MF can be transmitted only in a 1st DRS subframe. In yet another example, a PDCCH scheduling SIB-MF can be transmitted in a DRS subframe before which LBT is performed, i.e., a 1st subframe of every TxOP containing DRS. In a further example, a PDCCH scheduling SIB-MF can be transmitted in every DRS subframe.

[00128] In one example, the DRS can span over 12 RBs and can be repeated over two subframes. In another example, a legacy DRS can be contained in central RBs of a first subframe. In yet another example, a legacy DRS can be transmitted in the first or last 6 RBs of the first subframe. In a further example, a legacy DRS can be transmitted in the 6 RBs subsequent the first K RBs available. In yet a further example, the PSS/SSS/MF- PSS/MF-SSS can be scrambled between one set of RBs and the other, and between one time repetition and the other. Alternatively, different sequences can be used for some repetitions or set of RBs.

Design of Discovery Reference Signals for Wideband Coverage Enhancement (WCE) with subframe based CRS scrambling

[00129] The present technology relates to LTE operation in the unlicensed spectrum in MulteFire, and specifically to the wideband coverage enhancement (WCE) for MulteFire. For example, a discovery reference signal (DRS) design can be applied for WCE and/or eMTC based U-IoT systems, and the DRS design can use subframe based CRS scrambling.

[00130] In one example, a DRS design with same CRS scrambling can be defined. For example, in different DRS designs, the PSS/SSS and PBCH can be extended in time, with the same CRS scrambling being applied across multiple DRS subframes. This design can minimize implementation complexity, but can limit the legacy transmission on extended DRS subframes. Another design option is to encode a subframe index into a SSS, and then subframe based CRS scrambling can be used for an extended DRS design. For example, a different PSS/SSS design option can be defined that carries the subframe index and enables joint detecting with MFl .O PSS/SSS/ePSS/eSSS, where the ePSS is an enhanced PSS and the eSSS is an enhanced SSS.

[00131] In one example, an extended PSS/SSS design can be defined for MulteFire WCE, where the subframe index can be carried by the extended PSS/SSS. In a first alternative, an extended PSS can use 3 sequences and be repeated over multiple symbols. An extended SSS can be further scrambled by a subframe index 0-4/0-9 if DRS transmission window (DTxW) is 10ms. In a second alternative, an extended PSS can use only 1 sequence and be repeated over multiple symbols. An extended SSS can be further scrambled by subframe index 0-4/1-9 and 3 sector information. [00132] In one configuration, with respect to an extended PSS/SSS transmission technique, a DRS design for MulteFire WCE can be defined, where the DRS can span over one or multiple subframes. The first subframe can be a MulteFire 1.0 DRS subframe. A PSS/MF-PSS/SSS/MF-SSS transmission can occur on a legacy DRS. The MF-PSS can use 3 Zadoff-Chu (ZC) sequences with a different root index as compared to the PSS, and the MF-SSS can reuse the SSS sequence.

[00133] In a first alternative, an extended PSS can use 3 ZC sequences. When a further extended PSS for MF (MF-ePSS) is added in the 2nd subframe of the DRS, the MF-ePSS can carry 3 sector information, which is similar to the PSS/MF-PSS. This alternative can enable improved time/frequency synchronization and PCI detection probability. In one example, the MF-ePSS can reuse the 3 ZC sequence root index as the MF-PSS. Different cover codes can be applied to generate the MF-ePSS across multiple OFDM symbols. For example, if MF-ePSS is 6 symbols, then the cover code is 6 symbols long. In another example, the MF-ePSS can reuse the 3 ZC sequence root index as the PSS. Different cover codes can be applied to generate the MF-ePSS across multiple OFDM symbols. In yet another example, the MF-ePSS can use a different root index than one chosen by PSS/MF-PSS. For example, with 6 symbols fePSS, the root index can be { 1, 10, 2, 9, 3, 8 } . In addition, different combination of the root index pairs can be used to generate 3 different MF-ePSS.

[00134] In one example, a current LTE SSS can be generated using an interleaved m- sequence, which can be cyclic shifted and scrambled by a PSS root index to a different total of 504 PCIs and subframe 0 or 5. In one example, an extended SSS for MF (MF- eSSS) sequence can reuse the same SSS sequence, which can be further scrambled by an orthogonal sequence or pseudo-random sequence to carry subframe index 0-4 or 0-9. When an eDMTC window longer than 10ms is defined, the subframe index can be further extended to 0-7 or 0-13. The scrambling sequence can be an orthogonal sequence by properly choosing rows from a Hadamard matrix. As an alternative, a pseudo-random sequence, such as a ZC sequence, can be used. Here, the subframe index can correspond to the first MF-eSSS subframe, in case the MF-eSSS spans to more than 1 subframe. The subframe offset in the PBCH may not be used when carrying subframe index 0-9. In another example, a cover code can be utilized on the SSS to be spanned on multiple OFDM symbols, where the cover code on the MF-eSSS can be utilized to indicate subframe index information.

[00135] In one example, the MF-ePSS can be generated with a new root index to differentiate from the legacy PSS. Similarly, the MF-eSSS can be generated with a new root index to differentiate from the legacy SSS.

[00136] In one example, detection of the PSS/MF-PSS/MF-ePSS can be jointly detected. Detection of the SSS/MF-SSS/MF-eSSS can also be jointly detected. In another example, the MF-ePSS and MF-eSSS can be contained within a same subframe or in different subframes. In yet another example, the OFDM symbols that contain the MF- ePSS and/or the MF-eSSS can be different over different subframes depending on the corresponding performance.

[00137] In a second alternative, an extended PSS can use 1 ZC sequence. Similar to the PSS design principle, the MF-ePSS design can be only composed by one sequence, in order to enhance time and frequency detection performance. In this case, for WCE UEs, all PCI and subframe index detection can occur on the MF-eSSS. In one example, the MF-ePSS can reuse a single ZC sequence root index from the MF-PSS. Different cover codes can be applied to generate the MF-ePSS across multiple OFDM symbols. For example, if the MF-ePSS is 6 symbols, then the cover code is 6 symbols long. In another example, the MF-ePSS can reuse a single ZC sequence root index from the PSS. Different cover codes can be applied to generate the MF-ePSS across multiple OFDM symbols. In another example, the MF-ePSS can use a single ZC sequence root index differently than a 6 root index chosen for the PSS and MF-PSS. Different cover code can be applied to generate the MF-ePSS across multiple OFDM symbols. In another example, the MF- ePSS can use a different root index for each symbol other than one chosen by the PSS/MF-PSS. For example, with 6 symbols fePSS, the root index can be { 1, 10, 2, 9, 3, 8 } . Different cover codes can be applied to generate the MF-ePSS across multiple OFDM symbols.

[00138] In one example, the MF-eSSS sequence can be the same sequence as the SSS, which can be further scrambled by an orthogonal or a pseudo-random sequence to carry subframe index 0-4/0-9. The scrambling sequence can be an orthogonal sequence obtained by properly choosing rows from a Hadamard matrix. As an alternative, a pseudo-random sequence, such as a ZC sequence, can be used. In one example, when detecting the PSS/MF-PSS/MF-ePSS, only one root index can be detected, to improve time/frequency offset estimation. When detecting the SSS/MF-SSS/MF-eSSS, the UE can perform a joint decision among all 504x10 = 5040 possibilities to determine the PCI and subframe index.

[00139] In one example, with respect to a period configuration, an occasion of the MF- ePSS/MF-eSSS can be subsequent to an occasion of the legacy PSS/SSS. In another example, a period of the MF ePSS/MF-eSSS can be longer than a legacy PSS/SSS, e.g., 80ms, or 160ms. In yet another example, the MF-ePSS and MF-eSSS can be transmitted within a 9 subframe offset from a 1st subframe of an occasion window, irrespective of a length of the eDRS window. In a further example, if the MF-ePSS and MF-eSSS are transmitted after the 9 subframe offset, the MF-eSSS can carry more subframe index information, e.g., 1-15.

[00140] FIG. 18 illustrates an example of an extended discovery reference signal (eDRS) window. A legacy DRS period can span 40ms, and a legacy DRS window within the legacy DRS period can span 10ms. In contrast, an eDRS period can span 80ms, and an eDRS window can span 10ms or more than 10ms. In a first option, when the eDRS window spans 10ms, a legacy DRS, as well as an ePSS and/or eSSS, can be transmitted within the eDRS window. In a second option, when the eDRS window spans more than 10ms, a legacy DRS, as well as an ePSS and/or eSSS, can be transmitted partially within the eDRS window. For example, the legacy DRS can be transmitted within the eDRS window, and a start of the ePSS and/or eSSS transmission can be within the eDRS window but an end of the ePSS and/or eSSS transmission can be outside the eDRS window.

[00141] In one configuration, a DRS design for wideband coverage enhancement (WCE) is described. In one example, a first subframe can be a MulteFire 1.0 DRS subframe, while an extended DRS can be carried in subsequent subframes. In another example, the MF-ePSS can be added in a 2nd subframe of the DRS, and can carry 3 sector information.

[00142] In one example, the MF-ePSS can use 3 ZC sequences. In another example, the MF-ePSS can reuse a 3 ZC sequence root index from the MF-PSS, and different orthogonal cover codes (OCCs) can be applied to generate the MF-ePSS across multiple OFDM symbols. In yet another example, the MF-ePSS can reuse a 3 ZC sequence root index from the legacy PSS, and different OCCs can be applied to generate different MF- ePSS for multiple OFDM symbols. In a further example, the MF-ePSS can use a different root index other than those used in the MF-PSS and legacy PSS.

[00143] In one example, the MF-eSSS sequence can reuse a same SSS sequence, which can be further scrambled by an orthogonal or pseudo-random sequence to carry subframe index 0-4 or 0-9. In another example, a scrambling sequence can be an orthogonal sequence obtained by properly choosing rows from a Hadamard matrix. In yet another example, a pseudo-random sequence can be used.

[00144] In one example, a subframe index can correspond to a first MF-eSSS subframe, in case the MF-eSSS spans to more than 1 subframe. In another example, a subframe offset in a PBCH may not be used when carrying subframe index 0-9. In yet another example, a cover code can be utilized on the SSS to be spanned on multiple OFDM symbols, where the cover code on the MF-eSSS can be utilized to indicate subframe index information.

[00145] In one example, the PSS/MF-PSS/MF-ePSS can be jointly detected. In another example, the SSS/MF-SSS/MF-eSSS can be jointly detected. In yet another example, the MF-ePSS and MF-eSSS can be contained in the same subframe or in different subframes. In a further example, OFDM symbol dedicated to carry the MF-ePSS and/or MF-eSSS can be different over different subframes.

[00146] In one example, the MF-ePSS can use one ZC sequence. In another example, the MF-ePSS can reuse one ZC sequence root index from the MF-PSS, and different OCCs can be applied to generate different MF-ePSS across multiple OFDM symbols. In yet another example, the MF-ePSS can reuse one ZC sequence root index from the legacy PSS, and different OCCs can be applied to generate different MF-ePSS across multiple OFDM symbols.

[00147] In one example, the MF-ePSS can use one ZC sequence root index that is different from the root indexes chosen by the PSS and MF-PSS, and different OCCs can be applied to generate different MF-ePSS across multiple OFDM symbols. In another example, the MF-ePSS can use different root indexes for each symbol that are chosen to be different, and different OCCs can be applied to generate different MF-ePSS across multiple OFDM symbols. In yet another example, the MF-eSSS can reuse the same sequences as the SSS, which can be further scrambled by an orthogonal or pseudorandom sequence to carry subframe index 0-4/0-9.

[00148] In one example, the scrambling sequence can be an orthogonal sequence obtained by opportunely choosing certain rows from a Hadamard matrix. In another example, the scrambling sequence can be a pseudo-random sequence, such as a ZC sequence. In yet another example, only one root index can be detected when detecting the PSS/MF-PSS/MF-ePSS. In a further example, the UE can attempt to perform a joint decision among all 504x10 possible sequences to determine the PCI and subframe index.

[00149] In one example, the MF-ePSS/MF-eSSS can occur subsequently of the legacy PSS/SSS. In another example, the period of the MF-ePSS and MF-eSSS can be longer than that of the legacy PSS/SSS. In yet another example, the MF-ePSS and MF-eSSS can be transmitted within a 9 subframe offset from a 1st subframe, regardless of a length of a eDRS window. In a further example, the MF-eSSS can carry more subframe index information if the MF-ePSS and MF-eSSS are transmitted outside the 9 subframe offset.

[00150] Another example provides functionality 1900 of an eNodeB operable to encode a discovery reference signal (DRS) for transmission to a user equipment (UE), as shown in FIG. 19. The eNodeB can comprise one or more processors configured to identify, at an eNodeB that is configured to support Internet of Things (IoT) operation in an unlicensed spectrum (U-IoT), a DRS for transmission to the UE in accordance with a defined DRS configuration, wherein the DRS spans a DRS duration of one or more subframes, and the DRS in one subframe of the DRS duration includes one or more of: a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a cell- specific reference signal (CRS), or a physical broadcast channel (PBCH) signal, as in block 1910. The eNodeB can comprise one or more processors configured to encode, at the eNodeB, the DRS for transmission to the UE in accordance with the defined DRS configuration, as in block 1920. In addition, the eNodeB can comprise a memory interface configured to retrieve from a memory the defined DRS configuration

[00151] Another example provides functionality 2000 of an eNodeB operable to encode a discovery reference signal (DRS) for transmission in a wideband coverage enhancement for a MulteFire system, as shown in FIG. 20. The eNodeB can comprise one or more processors configured to identify, at the eNodeB, a DRS for transmission to a user equipment (UE) in the wideband coverage enhancement for the MulteFire system, wherein the DRS is transmitted in accordance with a defined DRS configuration and the DRS spans a DRS duration of multiple subframes, as in block 2010. The eNodeB can comprise one or more processors configured to encode, at the eNodeB, the DRS for transmission to the UE over the multiple subframes in accordance with the defined DRS configuration, as in block 2020. In addition, the eNodeB can comprise a memory interface configured to retrieve from a memory the defined DRS configuration.

[00152] Another example provides at least one machine readable storage medium having instructions 2100 embodied thereon for encoding a discovery reference signal (DRS) for transmission in a wideband coverage enhancement for a MulteFire system, as shown in FIG. 21. The instructions can be executed on a machine, where the instructions are included on at least one computer readable medium or one non-transitory machine readable storage medium. The instructions when executed by one or more processors of the eNodeB perform: identifying, at the eNodeB, a DRS for transmission to a user equipment (UE) in the wideband coverage enhancement for the MulteFire system, wherein the DRS is transmitted in accordance with a defined DRS configuration and the DRS spans a DRS duration of multiple subframes, as in block 2110. The instructions when executed by one or more processors of the eNodeB perform: encoding, at the eNodeB, the DRS for transmission to the UE in accordance with the defined DRS configuration, as in block 2120.

[00153] FIG. 22 illustrates an architecture of a system 2200 of a network in accordance with some embodiments. The system 2200 is shown to include a user equipment (UE) 2201 and a UE 2202. The UEs 2201 and 2202 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device, such as Personal Data Assistants (PDAs), pagers, laptop computers, desktop computers, wireless handsets, or any computing device including a wireless communications interface.

[00154] In some embodiments, any of the UEs 2201 and 2202 can comprise an Internet of Things (IoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity -Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network.

[00155] The UEs 2201 and 2202 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) 2210— the RAN 2210 may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. The UEs 2201 and 2202 utilize connections 2203 and 2204, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections 2203 and 2204 are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code- division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System

(UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (5G) protocol, a New Radio (NR) protocol, and the like.

[00156] In this embodiment, the UEs 2201 and 2202 may further directly exchange communication data via a ProSe interface 2205. The ProSe interface 2205 may alternatively be referred to as a sidelink interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH).

[00157] The UE 2202 is shown to be configured to access an access point (AP) 2206 via connection 2207. The connection 2207 can comprise a local wireless connection, such as a connection consistent with any IEEE 2302.15 protocol, wherein the AP 2206 would comprise a wireless fidelity (WiFi®) router. In this example, the AP 2206 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below).

[00158] The RAN 2210 can include one or more access nodes that enable the connections 2203 and 2204. These access nodes (ANs) can be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), next Generation NodeBs (gNB), RAN nodes, and so forth, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). The RAN 2210 may include one or more RAN nodes for providing macro cells, e.g., macro RAN node 2211, and one or more RAN nodes for providing femtocells or pico cells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macro cells), e.g., low power (LP) RAN node 2212.

[00159] Any of the RAN nodes 2211 and 2212 can terminate the air interface protocol and can be the first point of contact for the UEs 2201 and 2202. In some embodiments, any of the RAN nodes 2211 and 2212 can fulfill various logical functions for the RAN

2210 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

[00160] In accordance with some embodiments, the UEs 2201 and 2202 can be configured to communicate using Orthogonal Frequency-Division Multiplexing (OFDM) communication signals with each other or with any of the RAN nodes 2211 and 2212 over a multicarrier communication channel in accordance various communication techniques, such as, but not limited to, an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers.

[00161] In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 2211 and 2212 to the UEs 2201 and 2202, while uplink transmissions can utilize similar techniques. The grid can be a time- frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane

representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time- frequency unit in a resource grid is denoted as a resource element. Each resource grid comprises a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements; in the frequency domain, this may represent the smallest quantity of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks.

[00162] The physical downlink shared channel (PDSCH) may carry user data and higher-layer signaling to the UEs 2201 and 2202. The physical downlink control channel (PDCCH) may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs 2201 and 2202 about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE 2202 within a cell) may be performed at any of the RAN nodes 2211 and 2212 based on channel quality information fed back from any of the UEs 2201 and 2202. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs 2201 and 2202.

[00163] The PDCCH may use control channel elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub-block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as resource element groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the downlink control information (DCI) and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=l, 2, 4, or 8).

[00164] Some embodiments may use concepts for resource allocation for control channel information that are an extension of the above-described concepts. For example, some embodiments may utilize an enhanced physical downlink control channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more enhanced the control channel elements (ECCEs). Similar to above, each ECCE may correspond to nine sets of four physical resource elements known as an enhanced resource element groups (EREGs). An ECCE may have other numbers of EREGs in some situations.

[00165] The RAN 2210 is shown to be communicatively coupled to a core network (CN) 2220— via an SI interface 2213. In embodiments, the CN 2220 may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN. In this embodiment the SI interface 2213 is split into two parts: the S l-U interface 2214, which carries traffic data between the RAN nodes 2211 and 2212 and the serving gateway (S-GW) 2222, and the S I -mobility management entity (MME) interface 2215, which is a signaling interface between the RAN nodes 2211 and 2212 and MMEs 2221.

[00166] In this embodiment, the CN 2220 comprises the MMEs 2221, the S-GW 2222, the Packet Data Network (PDN) Gateway (P-GW) 2223, and a home subscriber server (HSS) 2224. The MMEs 2221 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs 2221 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 2224 may comprise a database for network users, including subscription-related information to support the network entities' handling of

communication sessions. The CN 2220 may comprise one or several HSSs 2224, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 2224 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc.

[00167] The S-GW 2222 may terminate the SI interface 2213 towards the RAN 2210, and routes data packets between the RAN 2210 and the CN 2220. In addition, the S-GW

2222 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement.

[00168] The P-GW 2223 may terminate an SGi interface toward a PDN. The P-GW

2223 may route data packets between the EPC network 2223 and external networks such as a network including the application server 2230 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 2225. Generally, the application server 2230 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this embodiment, the P-GW 2223 is shown to be communicatively coupled to an application server 2230 via an IP communications interface 2225. The application server 2230 can also be configured to support one or more communication services (e.g., Voice- over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 2201 and 2202 via the CN 2220.

[00169] The P-GW 2223 may further be a node for policy enforcement and charging data collection. Policy and Charging Enforcement Function (PCRF) 2226 is the policy and charging control element of the CN 2220. In a non-roaming scenario, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 2226 may be communicatively coupled to the application server 2230 via the P-GW 2223. The application server 2230 may signal the PCRF 2226 to indicate a new service flow and select the appropriate Quality of Service (QoS) and charging parameters. The PCRF 2226 may provision this rule into a Policy and Charging Enforcement Function (PCEF) (not shown) with the appropriate traffic flow template (TFT) and QoS class of identifier (QCI), which commences the QoS and charging as specified by the application server 2230.

[00170] FIG. 23 illustrates example components of a device 2300 in accordance with some embodiments. In some embodiments, the device 2300 may include application circuitry 2302, baseband circuitry 2304, Radio Frequency (RF) circuitry 2306, front-end module (FEM) circuitry 2308, one or more antennas 2310, and power management circuitry (PMC) 2312 coupled together at least as shown. The components of the illustrated device 2300 may be included in a UE or a RAN node. In some embodiments, the device 2300 may include less elements (e.g., a RAN node may not utilize application circuitry 2302, and instead include a processor/controller to process IP data received from an EPC). In some embodiments, the device 2300 may include additional elements such as, for example, memory/storage, display, camera, sensor, or input/output (I/O) interface. In other embodiments, the components described below may be included in more than one device (e.g., said circuitries may be separately included in more than one device for Cloud-RAN (C-RAN) implementations).

[00171] The application circuitry 2302 may include one or more application processors. For example, the application circuitry 2302 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with or may include memory /storage and may be configured to execute instructions stored in the memory /storage to enable various applications or operating systems to run on the device 2300. In some embodiments, processors of application circuitry 2302 may process IP data packets received from an EPC.

[00172] The baseband circuitry 2304 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 2304 may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry 2306 and to generate baseband signals for a transmit signal path of the RF circuitry 2306. Baseband processing circuity 2304 may interface with the application circuitry 2302 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 2306. For example, in some embodiments, the baseband circuitry 2304 may include a third generation (3G) baseband processor 2304a, a fourth generation (4G) baseband processor 2304b, a fifth generation (5G) baseband processor 2304c, or other baseband processor(s) 2304d for other existing generations, generations in development or to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuitry 2304 (e.g., one or more of baseband processors 2304a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 2306. In other embodiments, some or all of the functionality of baseband processors 2304a-d may be included in modules stored in the memory 2304g and executed via a Central Processing Unit (CPU) 2304e. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments,

modulation/demodulation circuitry of the baseband circuitry 2304 may include Fast- Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 2304 may include convolution, tail-biting convolution, turbo, Viterbi, or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

[00173] In some embodiments, the baseband circuitry 2304 may include one or more audio digital signal processor(s) (DSP) 2304f. The audio DSP(s) 2304f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 2304 and the application circuitry 2302 may be implemented together such as, for example, on a system on a chip (SOC).

[00174] In some embodiments, the baseband circuitry 2304 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 2304 may support communication with an evolved universal terrestrial radio access network (EUTRAN) or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 2304 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[00175] RF circuitry 2306 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 2306 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 2306 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 2308 and provide baseband signals to the baseband circuitry 2304. RF circuitry 2306 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 2304 and provide RF output signals to the FEM circuitry 2308 for transmission.

[00176] In some embodiments, the receive signal path of the RF circuitry 2306 may include mixer circuitry 2306a, amplifier circuitry 2306b and filter circuitry 2306c. In some embodiments, the transmit signal path of the RF circuitry 2306 may include filter circuitry 2306c and mixer circuitry 2306a. RF circuitry 2306 may also include synthesizer circuitry 2306d for synthesizing a frequency for use by the mixer circuitry 2306a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 2306a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 2308 based on the synthesized frequency provided by synthesizer circuitry 2306d. The amplifier circuitry 2306b may be configured to amplify the down-converted signals and the filter circuitry 2306c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 2304 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a necessity. In some embodiments, mixer circuitry 2306a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[00177] In some embodiments, the mixer circuitry 2306a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 2306d to generate RF output signals for the FEM circuitry 2308. The baseband signals may be provided by the baseband circuitry 2304 and may be filtered by filter circuitry 2306c.

[00178] In some embodiments, the mixer circuitry 2306a of the receive signal path and the mixer circuitry 2306a of the transmit signal path may include two or more mixers and may be arranged for quadrature down-conversion and up-conversion, respectively. In some embodiments, the mixer circuitry 2306a of the receive signal path and the mixer circuitry 2306a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 2306a of the receive signal path and the mixer circuitry 2306a may be arranged for direct down-conversion and direct up-conversion, respectively. In some embodiments, the mixer circuitry 2306a of the receive signal path and the mixer circuitry 2306a of the transmit signal path may be configured for super-heterodyne operation.

[00179] In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 2306 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 2304 may include a digital baseband interface to communicate with the RF circuitry 2306.

[00180] In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[00181] In some embodiments, the synthesizer circuitry 2306d may be a fractional-N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 2306d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[00182] The synthesizer circuitry 2306d may be configured to synthesize an output frequency for use by the mixer circuitry 2306a of the RF circuitry 2306 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 2306d may be a fractional N/N+l synthesizer. [00183] In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a necessity. Divider control input may be provided by either the baseband circuitry 2304 or the applications processor 2302 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 2302.

[00184] Synthesizer circuitry 2306d of the RF circuitry 2306 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[00185] In some embodiments, synthesizer circuitry 2306d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 2306 may include an IQ/polar converter.

[00186] FEM circuitry 2308 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 2310, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 2306 for further processing. FEM circuitry 2308 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 2306 for transmission by one or more of the one or more antennas 2310. In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry 2306, solely in the FEM 2308, or in both the RF circuitry 2306 and the FEM 2308.

[00187] In some embodiments, the FEM circuitry 2308 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include an LNA to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 2306). The transmit signal path of the FEM circuitry 2308 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 2306), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 2310).

[00188] In some embodiments, the PMC 2312 may manage power provided to the baseband circuitry 2304. In particular, the PMC 2312 may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMC 2312 may often be included when the device 2300 is capable of being powered by a battery, for example, when the device is included in a UE. The PMC 2312 may increase the power conversion efficiency while providing desirable implementation size and heat dissipation

characteristics.

[00189] While FIG. 23 shows the PMC 2312 coupled only with the baseband circuitry 2304. However, in other embodiments, the PMC 2312 may be additionally or

alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, application circuitry 2302, RF circuitry 2306, or FEM 2308.

[00190] In some embodiments, the PMC 2312 may control, or otherwise be part of, various power saving mechanisms of the device 2300. For example, if the device 2300 is in an RRC_Connected state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device 2300 may power down for brief intervals of time and thus save power.

[00191] If there is no data traffic activity for an extended period of time, then the device 2300 may transition off to an RRC Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device 2300 goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device 2300 may not receive data in this state, in order to receive data, it can transition back to

RRC Connected state.

[00192] An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable.

[00193] Processors of the application circuitry 2302 and processors of the baseband circuitry 2304 may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry 2304, alone or in combination, may be used execute Layer 3, Layer 2, or Layer 1 functionality, while processors of the application circuitry 2304 may utilize data (e.g., packet data) received from these layers and further execute Layer 4 functionality (e.g., transmission communication protocol (TCP) and user datagram protocol (UDP) layers). As referred to herein, Layer 3 may comprise a radio resource control (RRC) layer, described in further detail below. As referred to herein, Layer 2 may comprise a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, described in further detail below. As referred to herein, Layer 1 may comprise a physical (PHY) layer of a UE/RAN node, described in further detail below.

[00194] FIG. 24 illustrates example interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry 2304 of FIG. 23 may comprise processors 2304a-2304e and a memory 2304g utilized by said processors. Each of the processors 2304a-2304e may include a memory interface, 2404a-2404e, respectively, to send/receive data to/from the memory 2304g.

[00195] The baseband circuitry 2304 may further include one or more interfaces to communicatively couple to other circuitries/devices, such as a memory interface 2412 (e.g., an interface to send/receive data to/from memory external to the baseband circuitry 2304), an application circuitry interface 2414 (e.g., an interface to send/receive data to/from the application circuitry 2302 of FIG. 23), an RF circuitry interface 2416 (e.g., an interface to send/receive data to/from RF circuitry 2306 of FIG. 23), a wireless hardware connectivity interface 2418 (e.g., an interface to send/receive data to/from Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components), and a power management interface 2420 (e.g., an interface to send/receive power or control signals to/from the PMC 2312.

[00196] FIG. 25 provides an example illustration of the wireless device, such as a user equipment (UE), a mobile station (MS), a mobile wireless device, a mobile

communication device, a tablet, a handset, or other type of wireless device. The wireless device can include one or more antennas configured to communicate with a node, macro node, low power node (LPN), or, transmission station, such as a base station (BS), an evolved Node B (eNB), a baseband processing unit (BBU), a remote radio head (RRH), a remote radio equipment (RRE), a relay station (RS), a radio equipment (RE), or other type of wireless wide area network (WWAN) access point. The wireless device can be configured to communicate using at least one wireless communication standard such as, but not limited to, 3 GPP LTE, WiMAX, High Speed Packet Access (HSPA), Bluetooth, and WiFi. The wireless device can communicate using separate antennas for each wireless communication standard or shared antennas for multiple wireless communication standards. The wireless device can communicate in a wireless local area network

(WLAN), a wireless personal area network (WPAN), and/or a WWAN. The wireless device can also comprise a wireless modem. The wireless modem can comprise, for example, a wireless radio transceiver and baseband circuitry (e.g., a baseband processor). The wireless modem can, in one example, modulate signals that the wireless device transmits via the one or more antennas and demodulate signals that the wireless device receives via the one or more antennas.

[00197] FIG. 25 also provides an illustration of a microphone and one or more speakers that can be used for audio input and output from the wireless device. The display screen can be a liquid crystal display (LCD) screen, or other type of display screen such as an organic light emitting diode (OLED) display. The display screen can be configured as a touch screen. The touch screen can use capacitive, resistive, or another type of touch screen technology. An application processor and a graphics processor can be coupled to internal memory to provide processing and display capabilities. A non-volatile memory port can also be used to provide data input/output options to a user. The non-volatile memory port can also be used to expand the memory capabilities of the wireless device. A keyboard can be integrated with the wireless device or wirelessly connected to the wireless device to provide additional user input. A virtual keyboard can also be provided using the touch screen.

Examples

[00198] The following examples pertain to specific technology embodiments and point out specific features, elements, or actions that can be used or otherwise combined in achieving such embodiments.

[00199] Example 1 includes an apparatus of an eNodeB operable to encode a discovery reference signal (DRS) for transmission to a user equipment (UE), the apparatus comprising: one or more processors configured to: identify, at an eNodeB that is configured to support Internet of Things (IoT) operation in an unlicensed spectrum (U- IoT), a DRS for transmission to the UE in accordance with a defined DRS configuration, wherein the DRS spans a DRS duration of one or more subframes, and the DRS in one subframe of the DRS duration includes one or more of: a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a cell-specific reference signal (CRS), or a physical broadcast channel (PBCH) signal; and encode, at the eNodeB, the DRS for transmission to the UE in accordance with the defined DRS configuration; and a memory interface configured to retrieve from a memory the defined DRS configuration.

[00200] Example 2 includes the apparatus of Example 1, further comprising a transceiver configured to transmit the DRS to the UE.

[00201] Example 3 includes the apparatus of any of Examples 1 to 2, wherein the defined DRS configuration includes a first DRS configuration, in which: the DRS in the subframe of the DRS duration includes the PSS, the SSS, the CRS and the PBCH signal; the PSS is present at symbol 6 of the subframe and the SSS is present at symbol 5 of the subframe; the CRS is present in one or more orthogonal frequency division multiplexing (OFDM) symbols within a set of OFDM symbols consisting of symbols {0, 1, 4, 7, 8 or 11 } in the subframe; and a master information block (MIB) is transmitted in one or multiple OFDM symbols within a set of OFDM symbols consisting of symbols {7, 8, 9, 10, 0, 1, 2, 3, 4, 11, 12, 13} in the subframe.

[00202] Example 4 includes the apparatus of any of Examples 1 to 3, wherein PBCH symbols are repeated or the MIB is rate matched to selected OFDM symbols, when the MIB is transmitted over selected OFDM symbols in addition to OFDM symbols in a set of OFDM symbols consisting of symbols {7, 8, 9, 10} in the subframe.

[00203] Example 5 includes the apparatus of any of Examples 1 to 4, wherein the defined DRS configuration includes a second DRS configuration, in which: the DRS in the subframe of the DRS duration includes the PSS, the SSS, the CRS and the PBCH signal; the PSS is present at symbol 6 of the subframe and the SSS is present at symbol 5 of the subframe; an additional PSS and an additional SSS are present at one or more of symbol 2 or symbol 3 of the subframe; the CRS is present in one or more orthogonal frequency division multiplexing (OFDM) symbols within a set of OFDM symbols consisting of symbols {0, 1, 4, 7, 8 or 11 } in the subframe; and a master information block (MIB) is transmitted in one or multiple OFDM symbols within: a set of OFDM symbols consisting of symbols {7, 8, 9, 10, 0, 1, 3, 4, 11, 12, 13} in the subframe when symbol 2 of the subframe is used for the additional PSS and the additional SSS, a set of OFDM symbols consisting of symbols {7, 8, 9, 10, 0, 1, 2, 4, 11, 12, 13} in the subframe when symbol 3 of the subframe is used for the additional PSS and the additional SSS, or a set of OFDM symbols consisting of symbols {7, 8, 9, 10, 0, 1, 4, 11, 12, 13} in the subframe when symbol 2 and symbol 3 of the subframe are used for the additional PSS and the additional SSS.

[00204] Example 6 includes the apparatus of any of Examples 1 to 5, wherein the defined DRS configuration includes a third DRS configuration, in which: the DRS in the subframe of the DRS duration includes the CRS and the PBCH signal and does not include the PSS and the SSS; the CRS is present in one or more orthogonal frequency division multiplexing (OFDM) symbols within a set of OFDM symbols consisting of symbols {0, 1, 4, 7, 8 or 11 } in the subframe; and a master information block (MIB) is transmitted in one or multiple OFDM symbols within a set of OFDM symbols consisting of symbols {7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 11, 12, 13} in the subframe. [00205] Example 7 includes the apparatus of any of Examples 1 to 6, wherein the DRS in each subframe of the one or more subframes follows one of a first DRS configuration, a second DRS configuration or a third DRS configuration.

[00206] Example 8 includes the apparatus of any of Examples 1 to 7, wherein the one or more processors are further configured to perform a listen before talk (LBT) procedure before performing a DRS transmission.

[00207] Example 9 includes the apparatus of any of Examples 1 to 8, wherein the one or more processors are further configured to encode the DRS for transmission on one or multiple anchor channels, wherein the DRS is transmitted with a fixed periodicity during a dwell time of a given anchor channel.

[00208] Example 10 includes the apparatus of any of Examples 1 to 9, wherein the eNodeB is configured to support a wideband coverage enhancement for MulteFire 1.0.

[00209] Example 11 includes an apparatus of an eNodeB operable to encode a discovery reference signal (DRS) for transmission in a wideband coverage enhancement for a MulteFire system, the apparatus comprising: one or more processors configured to: identify, at the eNodeB, a DRS for transmission to a user equipment (UE) in the wideband coverage enhancement for the MulteFire system, wherein the DRS is transmitted in accordance with a defined DRS configuration and the DRS spans a DRS duration of multiple subframes; and encode, at the eNodeB, the DRS for transmission to the UE over the multiple subframes in accordance with the defined DRS configuration; and a memory interface configured to retrieve from a memory the defined DRS configuration.

[00210] Example 12 includes the apparatus of Example 11, wherein the one or more processors are configured to: perform a listen before talk (LBT) procedure before a first DRS subframe in the multiple subframes; and encode the DRS for transmission to the UE in the multiple subframes in accordance with the defined DRS configuration.

[00211] Example 13 includes the apparatus of any of Examples 11 to 12, wherein selected symbols in the multiple subframes are punctured to create multiple listen before talk (LBT) gaps.

[00212] Example 14 includes the apparatus of any of Examples 11 to 13, wherein the one or more processors are configured to: perform single-interval LBT before each DRS subframe in the multiple subframes, and each DRS subframe occupies 12 orthogonal frequency division multiplexing (OFDM) symbols; or perform Category 4 LBT with priority 1 before every two DRS subframes in the multiple subframes, wherein a selected number of last symbols of the every two DRS subframes are punctured for a LBT gap, wherein the selected number of last symbols is one or two symbols.

[00213] Example 15 includes the apparatus of any of Examples 11 to 14, wherein the one or more processors are configured to encode the DRS for transmission to the UE over two subsequent subframes in the multiple subframes that span over 12 resource blocks (RBs) in a frequency domain in accordance with the defined DRS configuration.

[00214] Example 16 includes the apparatus of any of Examples 11 to 15, wherein the DRS in one subframe of the DRS duration includes one or more of: a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a cell-specific reference signal (CRS), a physical broadcast channel (PBCH) signal or a system information block for MulteFire (SIB-MF).

[00215] Example 17 includes the apparatus of any of Examples 11 to 16, wherein the eNodeB is configured to support the wideband coverage enhancement for MulteFire 1.0.

[00216] Example 18 includes at least one machine readable storage medium having instructions embodied thereon for encoding a discovery reference signal (DRS) for transmission in a wideband coverage enhancement for a MulteFire system, the instructions when executed by one or more processors at an eNodeB perform the following: identifying, at the eNodeB, a DRS for transmission to a user equipment (UE) in the wideband coverage enhancement for the MulteFire system, wherein the DRS is transmitted in accordance with a defined DRS configuration and the DRS spans a DRS duration of multiple subframes; and encoding, at the eNodeB, the DRS for transmission to the UE in accordance with the defined DRS configuration.

[00217] Example 19 includes the at least one machine readable storage medium of Example 18, wherein the multiple subframes that carry the DRS includes a first subframe and a subsequent subframe, wherein the first subframe is a MulteFire 1.0 DRS subframe and the subsequent subframe is an extended DRS subframe. [00218] Example 20 includes the at least one machine readable storage medium of any of Examples 18 to 19, wherein the subsequent subframe includes: a MulteFire extended primary synchronization signal (MF-ePSS); and a MulteFire extended secondary synchronization signal (MF-eSSS).

[00219] Example 21 includes the at least one machine readable storage medium of any of Examples 18 to 20, wherein: the MF-ePSS uses three Zadoff-Chu (ZC) sequences, and the MF-ePSS repeats over multiple symbols in the subsequent subframe; or the MF-ePSS uses one ZC sequence, and the MF-ePSS repeats over multiple symbols in the subsequent subframe.

[00220] Example 22 includes the at least one machine readable storage medium of any of Examples 18 to 21, wherein the MF-eSSS is scrambled by an orthogonal or pseudorandom sequence to carry a subframe index 0-4 or 0-9, wherein the subframe index is encoded into the MF-eSSS to achieve subframe based cell-specific reference signal (CRS) scrambling for the defined DRS configuration.

[00221] Example 23 includes the at least one machine readable storage medium of any of Examples 18 to 22, further comprising instructions when executed perform the following: configuring the UE to perform joint detection of a primary synchronization signal (PSS), a MulteFire PSS (MF-PSS) and an extended MulteFire PSS (MF-ePSS); and configuring the UE to perform joint detection of a secondary synchronization signal (SSS), a MulteFire SSS (MF-SSS) and an extended MulteFire SSS (MF-eSSS), wherein the MF-ePSS and the MF-eSSS are included within the multiple subframes in accordance with the defined DRS configuration.

[00222] Example 24 includes an eNodeB operable to encode a discovery reference signal (DRS) for transmission in a wideband coverage enhancement for a MulteFire system, the eNodeB comprising: means for identifying, at the eNodeB, a DRS for transmission to a user equipment (UE) in the wideband coverage enhancement for the MulteFire system, wherein the DRS is transmitted in accordance with a defined DRS configuration and the DRS spans a DRS duration of multiple subframes; and means for encoding, at the eNodeB, the DRS for transmission to the UE in accordance with the defined DRS configuration.

[00223] Example 25 includes the eNodeB of Example 24, wherein the multiple subframes that carry the DRS includes a first subframe and a subsequent subframe, wherein the first subframe is a MulteFire 1.0 DRS subframe and the subsequent subframe is an extended DRS subframe.

[00224] Example 26 includes the eNodeB of any of Examples 24 to 25, wherein the subsequent subframe includes: a MulteFire extended primary synchronization signal (MF-ePSS); and a MulteFire extended secondary synchronization signal (MF-eSSS).

[00225] Example 27 includes the eNodeB of any of Examples 24 to 26, wherein: the MF-ePSS uses three Zadoff-Chu (ZC) sequences, and the MF-ePSS repeats over multiple symbols in the subsequent subframe; or the MF-ePSS uses one ZC sequence, and the MF- ePSS repeats over multiple symbols in the subsequent subframe.

[00226] Example 28 includes the eNodeB of any of Examples 24 to 27, wherein the MF-eSSS is scrambled by an orthogonal or pseudo-random sequence to carry a subframe index 0-4 or 0-9, wherein the subframe index is encoded into the MF-eSSS to achieve subframe based cell-specific reference signal (CRS) scrambling for the defined DRS configuration.

[00227] Example 29 includes the eNodeB of any of Examples 24 to 28, further comprising: means for configuring the UE to perform joint detection of a primary synchronization signal (PSS), a MulteFire PSS (MF-PSS) and an extended MulteFire PSS (MF-ePSS); and means for configuring the UE to perform joint detection of a secondary synchronization signal (SSS), a MulteFire SSS (MF-SSS) and an extended MulteFire SSS (MF-eSSS), wherein the MF-ePSS and the MF-eSSS are included within the multiple subframes in accordance with the defined DRS configuration.

[00228] Various techniques, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, compact disc-read-only memory (CD-ROMs), hard drives, non-transitory computer readable storage medium, or any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the various techniques. In the case of program code execution on programmable computers, the computing device may include a processor, a storage medium readable by the processor (including volatile and nonvolatile memory and/or storage elements), at least one input device, and at least one output device. The volatile and non-volatile memory and/or storage elements may be a random-access memory (RAM), erasable programmable read only memory (EPROM), flash drive, optical drive, magnetic hard drive, solid state drive, or other medium for storing electronic data. The node and wireless device may also include a transceiver module (i.e., transceiver), a counter module (i.e., counter), a processing module (i.e., processor), and/or a clock module (i.e., clock) or timer module (i.e., timer). In one example, selected components of the transceiver module can be located in a cloud radio access network (C-RAN). One or more programs that may implement or utilize the various techniques described herein may use an application programming interface (API), reusable controls, and the like. Such programs may be implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the program(s) may be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations.

[00229] As used herein, the term "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware.

[00230] It should be understood that many of the functional units described in this specification have been labeled as modules, in order to more particularly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

[00231] Modules may also be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module may not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module.

[00232] Indeed, a module of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network. The modules may be passive or active, including agents operable to perform desired functions.

[00233] Reference throughout this specification to "an example" or "exemplary" means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the present technology. Thus, appearances of the phrases "in an example" or the word "exemplary" in various places throughout this specification are not necessarily all referring to the same embodiment.

[00234] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present technology may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as defacto equivalents of one another, but are to be considered as separate and autonomous representations of the present technology. [00235] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of layouts, distances, network examples, etc., to provide a thorough understanding of embodiments of the technology. One skilled in the relevant art will recognize, however, that the technology can be practiced without one or more of the specific details, or with other methods, components, layouts, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the technology.

[00236] While the forgoing examples are illustrative of the principles of the present technology in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the technology.