RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application No. 62/202,679, which was filed on August 7, 2015, the contents of which is hereby incorporated by reference as though fully set forth herein.

BACKGROUND

The demand for wireless broadband data has consistently increased. Unlicensed spectrum (i.e., frequency spectrum that does not require a license from an appropriate regulating entity) is being considered by wireless cellular network operators to increase the capacity of existing services that are offered over licensed spectrum.

The use of unlicensed spectrum in the Third Generation Partnership Project (3GPP) Long Term Evolution-Advanced (LTE-A) system has been proposed as Licensed Assisted Access (LAA). Under LAA, the LTE standard is extended into unlicensed frequency deployments, thus enabling operators and vendors to maximally leverage the existing or planned investments in LTE hardware in the radio and core network.

One concern with LAA is the co-existence of the LTE radio nodes and other unlicensed radio nodes, such as WiFi systems operating in the same frequency band. To enable the coexistence of the LTE radio nodes and other unlicensed nodes, listen-before-talk (LBT) has been proposed. LBT is a contention protocol in which the LTE radio node determines whether a particular frequency channel is already occupied (e.g., by a WiFi node) before using the particular frequency channel.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments described herein will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals may designate like structural elements. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

Fig. 1 is a diagram of an example environment in which systems and/or methods described herein may be implemented;

Fig. 2 is a diagram illustrating example of an environment in which techniques described herein may be implemented; Fig. 3 is a flowchart illustrating an example process for dynamic transmission point selection;

Figs. 4-6 are flowcharts illustrating various embodiments relating to the scheduling of transmission points in dynamic point selection; and

Fig. 7 illustrates, for one embodiment, example components of an electronic device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments described herein are defined by the appended claims and their equivalents.

Techniques described herein relate to the use of Coordinated Multipoint Transmission (CoMP) techniques to improve LTE-A performance with LAA. LBT, when performed by an LTE transmission point using LAA, can limit the scheduling opportunity of downlink transmissions, such as downlink transmission via the Physical Downlink Shared Channel (PDSCH) or Enhanced Physical Downlink Control Channel (EPDCCH) transmission. In particular, when the unlicensed frequency channel is determined to be occupied, the LTE radio node may "back-off' from the frequency channel (i.e., refrain from transmitting to the channel) for a particular time period. Consistent with aspects described herein, the opportunity for User Equipment (UE) downlink scheduling can be increased by dynamically switching the downlink transmission to an LTE-LAA transmission point (i.e., an LTE transmission point performing LAA) that has a free downlink channel identified by LBT.

Fig. 1 is a diagram of an example environment 100, in which systems and/or methods described herein may be implemented. As illustrated, environment 100 may include User Equipment (UE) 1 10, which may obtain network connectivity from wireless network 120. Although a single UE 1 10 is shown, for simplicity, in Fig. 1 , in practice, multiple UEs 1 10 may operate in the context of a wireless network. Wireless network 120 may provide access to one or more external networks, such as packet data network ("PDN") 150. The wireless network may include radio access network ("RAN") 130 and core network 140. RAN 130 may be a E- UTRA based radio access network or another type of radio access network. Some or all of RAN 130 may be associated with a network operator that controls or otherwise manages core network 140. Core network 140 may include an Internet Protocol ("IP")-based network.

UE 1 10 may include a portable computing and communication device, such as a personal digital assistant ("PDA"), a smart phone, a cellular phone, a laptop computer with connectivity to a cellular wireless network, a tablet computer, etc. UE 1 10 may also include non-portable computing devices, such as desktop computers, consumer or business appliances, or other devices that have the ability to wirelessly connect to RAN 130.

UEs 1 10 may be designed to operate using LTE-LAA. For instance, UEs 1 10 may include radio circuitry that is capable of simultaneously receiving multiple carriers: a first, primary, carrier using licensed spectrum and a second carrier using unlicensed spectrum. The second carrier may correspond to, for example, the unlicensed 5 GHz spectrum. This spectrum may commonly be used by WiFi devices. A goal of LTE-LAA may be to not impact WiFi services more than an additional WiFi network on the same carrier.

UEs 1 10 capable of operating on the unlicensed band may be configured to make measurements to support unlicensed band operation, including providing feedback when the UE is in the coverage area of an LTE-LAA node. Once the connection is activated to allow use on the unlicensed band, existing Channel Quality Information (CQI) feedback may allow the eNBs 136 to determine what kind of quality could be achieved on the unlicensed band compared to the licensed band. Downlink only mode is particularly suited for situations where data volumes are dominated by downlink traffic.

RAN 130 may represent a 3GPP access network that includes one or more access technologies. RAN 130 may particularly include multiple eNBs 136. eNBs 136 may include eNBs that provide coverage to a relatively large (macro cell) area or a relatively small (small cell) area. Small cells may be deployed to increase system capacity by including a coverage area within a macro cell. Small cells may include picocells, femtocells, and/or home NodeBs. eNBs 136 can potentially include remote radio heads (RRH), such as RRHs 138. RRHs 138 can extend the coverage of an eNB by distributing the antenna system of the eNB. RRHs 138 may be connected to eNB 136 by optical fiber (or by another low-latency connection).

In the discussion herein, LTE-LAA nodes will be referred to as "transmission points." An LTE-LAA transmission point may correspond to an eNB 136 (macro cell or small cell) or to an RRH 138. In some implementations, the LTE-LAA transmission point (using unlicensed frequency) may be co-located with a corresponding eNB that uses licensed frequency. The licensed frequency eNBs and the LTE-LAA transmission points may maximize downlink bandwidth by performing carrier aggregation of the licensed and unlicensed bands. Core network 140 may include an IP-based network. In the 3GPP network architecture, core network 140 may include an Evolved Packet Core (EPC). As illustrated, core network 140 may include serving gateway (SGW) 142, Mobility Management Entity (MME) 144, and packet data network gateway (PG W) 146. Although certain network devices are illustrated in environment 100 as being part of RAN 130 and core network 140, whether a network device is labeled as being in the "RAN" or the "core network" of environment 100 may be an arbitrary decision that may not affect the operation of wireless network 120.

SGW 142 may include one or more network devices that aggregate traffic received from one or more eNBs 136. SGW 142 may generally handle user (data) plane traffic. MME 144 may include one or more computation and communication devices that perform operations to register UE 1 10 with core network 140, establish bearer channels associated with a session with UE 1 10, hand off UE 1 10 from one eNB to another, and/or perform other operations. MME 144 may generally handle control plane traffic.

PGW 146 may include one or more devices that act as the point of interconnect between core network 140 and external IP networks, such as PDN 150, and/or operator I P services. PGW 146 may route packets to and from the access networks, and the external IP networks.

PDN 150 may include one or more packet-based networks. PDN 150 may include one or more external networks, such as a public network (e.g., the Internet) or proprietary networks that provide services that are provided by the operator of core network 140 (e.g., IP multimedia (IMS)-based services, transparent end-to-end packet-switched streaming services (PSSs), or other services).

A number of interfaces are illustrated in Fig. 1 . An interface may refer to a physical or logical connection between devices in environment 100. The illustrated interfaces may be 3GPP standardized interfaces. For example, as illustrated, communication eNBs 136 may

communicate with SGW 142 and MME 144 using the S I interface (e.g., as defined by the 3GPP standards). eNBs 136 may communicate with one another via the X2 interface.

The quantity of devices and/or networks, illustrated in Fig. 1 , is provided for explanatory purposes only. In practice, there may be additional devices and/or networks; fewer devices and/or networks; different devices and/or networks; or differently arranged devices and/or networks than illustrated in Fig. 1 . Alternatively, or additionally, one or more of the devices of environment 100 may perform one or more functions described as being performed by another one or more of the devices of environment 100. Furthermore, while "direct" connections are shown in Fig. 1 , these connections should be interpreted as logical communication pathways, and in practice, one or more intervening devices (e.g., routers, gateways, modems, switches, hubs, etc.) may be present.

Fig. 2 is a diagram illustrating an example of an environment 200 in which techniques described herein may be implemented. Environment 200 may represent a particular example of portions of a RAN 130, including three LTE-LAA transmission points 210, 215, and 220. The LTE-LTE transmission points may correspond to eNBs 136. CoMP may be implemented between transmission points 210, 21 5, and 220. For example, transmission points 210, 215, and 220 may be coupled via a backhaul link, such as a proprietary or standardized interface. In one implementation, a coordination component, illustrated as coordination server 230, may be used to receive communications from transmission points 210-220 and coordinate actions of transmission of points 210-220. Coordination server 230 may be coupled to transmission points 210-220 via a backhaul link or other link.

Coverage areas for points 210, 215, and 220 are correspondingly illustrated as ovals 210- 1 , 215- 1 , and 220- 1 . Coverage areas 210- 1 , 215-1 , and 220- 1 may correspond to coverage via unlicensed spectrum using LAA.

Coordination server 230 may include one or more co-located or distributed computing devices that provide coordination and control functions relating to LAA functions. Coordination server 230 may be implemented as, for example, a network device (or multiple network devices) associated with RAN 130 or core network 140. The operation of coordination server 230 will be described in more detail below.

As mentioned, under LAA, it may be desirable for the LTE nodes operating in the unlicensed spectrum (e.g., transmission points 210, 215, and 220) to coexist with nearby WiFi networks or LTE LAA networks of other operator(s). Two example WiFi networks (e.g., WiFi Access Points (APs)) are illustrated in Fig. 2: WiFi AP 240 and WiFi AP 245. WiFi APs 240 and 245 may be, for example, operated independently of the operator of wireless network 120. Example coverage areas of WiFi APs 240 and 245 are shown as shaded ovals.

As mentioned, it may be desirable for WiFi APs 240 and 245 and transmission points 210-220 to co-exist with one another, such that both types of devices may continue to function despite the fact that they may both use the same unlicensed frequency spectrum. One co- existence mechanism is known as Clear Channel Assessment (CCA) or as Listen-Before-Talk (LBT). Under LBT, a transmission point, such as transmission point 210, before using an unlicensed frequency channel, may perform a "listen" operation on the channel (e.g., based on passively receiving the frequency channel) to determine if the channel is being used. If the channel is being used, such as by WiFi AP 240, transmission point 210 may refrain from using the channel (e.g., perform a "back-off operation for a particular time period). When the channel is not being used, transmission point 210 may transmit to a UE.

UEs 250, 255, and 260 are additionally illustrated in Fig. 2. In this example, assume that UEs 250 and 260 are connected to WiFi APs 240 and 245, respectively. UEs 250 and 260 may represent portable devices that connect to external WiFi networks. UE 255 may represent a customer of wireless network 120. That is, UE 255 may be LAA-capable and be connected to RAN 130 via a first carrier using licensed spectrum and a second carrier using unlicensed spectrum. Transmission points 210, 215, and 220 may provide LAA unlicensed access points. In some implementations, the licensed connection points (e.g., macro eNBs or small cells) may be co-deployed with transmission points 210, 215, and 220 or separately deployed.

In certain existing LTE LAA systems, UE 255 may be served by a single transmission point, such as transmission point 210. Serving transmission point 210 may be selected based on, for example, the maximum reference signal received power (RSRP) measured at UE 255.

Serving transmission point 21 0, prior to the downlink transmission, may perform LBT by detecting the presence of the transmission from the neighboring transmission points (e.g. WiFi APs 240 and 245). If the LBT indicates that the channel is occupied (e.g. when the measured received power at the serving transmission point 210 exceeds a certain threshold) serving transmission point 210 may apply back-off by deferring its downlink transmission for some amount of time. If the activity of the nearby transmission points, such as WiFi AP 240/245 becomes high, the downlink scheduling opportunities for PDSCH or EPDCCH from serving transmission, point 210 can be limited and downlink throughput performance degraded. In this case, it may be desirable to dynamically select and use another transmission point (e.g., transmission point 215 or 220) for the LTE-LAA downlink communication.

Fig. 3 is a flowchart illustrating an example process 300 for dynamic point selection.

Process 300 may be performed by, for example, coordination server 230 and/or UE 255. By dynamically selecting transmission points, as described herein, the opportunity for downlink scheduling, to a UE, over unlicensed frequency spectrum, may be increased. Advantageously, the RAN throughput may be increased.

Process 300 may include configuring parameters for two or more transmission points that are eligible to participate in dynamic transmission point selection (block 310). For instance, UE 255 may be informed, by coordination server 230, of the potential transmission points that may transmit downlink data, to UE 255, using LTE-LAA. For example, coordination server 230 may transmit cell identifiers (IDs), or other identifiers, to UE 255, to identify the potential LTE- LAA transmission points that UE 255 may use. Alternatively or additionally, UE 255 may receive information about reference signals transmitted by the LAA transmission points that should be used for timing and/or frequency synchronization, identification of PDSCH-related parameters (e.g., the PDSCH Resource Element (RE) mapping patterns for the transmission points, etc.), or other parameters that may be required for UE 255 to receive downlink communications via LTE-LAA.

In some implementations, coordination server 230 may configure transmission points 210-220 to enable two or more of transmission points 210-220 to be eligible for dynamic point selection. For example, based on the coverage areas of various overlapping transmission points, coordination server 230 may determine that there may be certain areas in which the UE could potentially receive LAA service from multiple points.

Process 300 may further include identifying the channel occupancy status at each participating transmission point (block 320). In one implementation, transmission points 210- 220 may measuring the occupancy status of particular unlicensed frequency carriers, such as by measuring the occupancy status as part of a LBT operation. Alternatively or additionally, transmission points 210-220 may, at periodic or at aperiodic intervals, measure the occupancy status of the particular unlicensed frequency carriers, even if there is no UE that is actively receiving downlink data from the transmission point. The channels may correspond to common unlicensed frequency bands, such as WiFi frequency bands. Transmission points 210-220 may communicate results of the measurement to coordination server 230, such as via low latency backhaul links.

Process 300 may further include dynamically selecting transmission points to coordinate LAA downlink transmission (block 330). For example, coordination server 230, based on the occupancy status information that is received from transmission points 210-220, may determine which transmission point is to transmit to a particular UE. In general, coordination server 230 may select a transmission point in which the LBT occupancy status indicates that the channel is open. When a UE is within the coverage area of multiple transmission points, coordination server may dynamically select transmission points to optimize throughput to the UE (e.g., coordination server 230 may dynamically switch transmission points based on the channel being open with the UE).

Process 300 may further include performing LAA downlink transmission using the selected transmission points (block 340). For example, coordination server 230 may forward downlink data, associated with the UE, to the transmission point associated with the unoccupied channel. The transmission point may subsequently communicate, using the unlicensed channel, the downlink data to the UE.

As an example of the operation of process 300 in environment 200, assume that LAA is being used in a manner that co-exists with a WiFi deployment that contains APs 240/245. In some existing systems, a target UE, such as UE 255, may be served by the single transmission point 210. The serving transmission point could be selected based on the maximum RSRP measured at the UE. Prior to downlink transmission, serving transmission point 210 may perform an LBT operation by detecting the presence of the transmission from the neighboring transmission points (e.g., WiFi AP 240). If the LBT operation indicates that the channel is occupied (e.g. when the measured received energy at the transmission point 210 exceeds a certain threshold) transmission point 210 may apply a back-off operation by deferring its downlink transmission for some amount of time.

With process 300, however, UE 255 may be served by one or more neighboring

(coordinating) transmission points that also perform the LBT operation. If an LBT operation on the neighboring transmission points detects an open channel, the downlink transmission (e.g., PDSCH or EPDCCH) to UE 255 may be performed from that LTE-LAA transmission point. Such dynamic point switching can become especially useful when the serving LTE-LAA transmission point is not able to schedule the UE for downlink transmission due to occupied downlink channels that are detected via LBT.

One example embodiment, relating to dynamic point selection for LTE-LAA, will next be described with reference to Fig. 4. Fig. 4 is a flowchart illustrating an example process 400 relating to the performance of timing and frequency adjustments at UE 255. Process 400 may be performed by, for example, UE 255. Enabling UE 255 to perform timing and frequency adjustments of received data signals may be necessary for UE 255 to be able to accurately receive data from both the serving LTE-LAA transmission point (e.g., the transmission point to which UE 255 initially connects based on maximum signal power, such as transmission point 210) and the coordinating LTE-LAA transmission points (e.g., the transmission points that may be dynamically selected as alternative transmission points, such as transmission points 215 and 220).

Process 400 may include receiving scheduling information via the licensed carrier (block 410). In other words, a cross-carrier scheduling mechanism may be used via which eNBs 136 transmit, via the licensed carrier, scheduling information for UE 255. The scheduling information may include the PDSCH RE mapping patterns for the transmission points. That is, the scheduling information may effectively indicate from which transmission point UE 255 is to receive downlink data.

Frequency errors in Orthogonal Frequency-Division Multiplexing (OFDM) systems may be referred to as carrier frequency offset (CFO). CFO can be caused by frequency differences between the transmitter and receiver oscillators, Doppler shift of mobile channels, or oscillator instabilities. CFO can be compensated for, at the receiver, using pre-FFT and post-FFT synchronization techniques.

Process 400 further include determining pre-FFT (Fast Fourier Transform) timing and frequency synchronization (block 420). The pre-FFT timing and frequency synchronization may be based on the Discovery Reference Signal (DRS) from the serving LTE-LAA

transmission point (e.g., the transmission point to which UE 255 initially connects based on maximum signal power).

Process 400 may further including receiving data from the coordinating transmission point (block 430). The downlink data, for the UE, may be extracted from the PDSCH using the scheduling information (e.g., the RE mapping patterns) that were previously received via the licensed carrier.

Process 400 may further include performing post-FFT timing and frequency

synchronization based on the Demodulation Reference Signal (DM-RS) of the coordinating transmission point (block 440). The DM-RS may be transmitted, together with the downlink data, from the coordinating transmission point. Based on the DM-RS, the UE may perform additional timing and frequency synchronization (post-FFT timing and frequency compensation) to enable accurate reception of the downlink transmission, form the coordinating transmission point, via LTE-LAA.

In one implementation, the operations of process 400 may be achieved using a quasi co- location (QCL) type, in which the DM-RS is not quasi co-located with other DRSes and QCL signaling does not need to be provided by the network for the DM-RS demodulation.

A second example embodiment, relating to dynamic point selection for LTE-LAA, wi ll next be described with reference to Fig. 5. Fig. 5 is a flowchart illustrating an example process 500 relating to the scheduling of transmission points for LTE-LAA. Process 500 may be performed by, for example, UE 255.

Process 500 may include receiving scheduling information via the licensed carrier (block 10). In other words, a cross-carrier scheduling mechanism may be used via which eNBs transmit, via the licensed carrier, scheduling information for UE 255. The scheduling information may implicitly indicate the transmission point that is to be used by the UE (block 5 10). In one implementation, the implicit indication of the transmission point may be provided as an indication of a particular DRS to use to obtain the timing and frequency synchronization parameters. For example, each of transmission points 210-220 may transmit a separate DRS. UE 255 may be able to receive each of the DRSs and thus potentially extract multiple potential timing and frequency synchronization offsets. The scheduling information may include an indication of a particular DRS to use, and hence of a particular transmission point.

In one implementation, the particular DRS to use may be indicated via an index value or other value included in the Downlink Control Information (DCI) field, which may be included in the Physical Downlink Control Channel (PDCCH) that is received via the licensed frequency band. The DCI may function as a map for the UE to find and decode PDSCH from the resource grid. A number of different DCI formats are possible. In one implementation, for the 3GPP Transmission Mode (TM) 10, the existing two-bit PDSCH RE mapping and quasi-colocation indication field may be reused to instead include an index value that references the particular DRS to use. For a two-bit field, up to four different DRSs, and hence up to four transmission points, may be indexed. In various implementations, indexing of the DRS to use may be implemented by implemented by providing indexing information in the LAA discovery reference signal identity (or parameters), the LAA initial signal identity (or parameters), or other reference signal identification parameter corresponding to the possible transmission points defined to support LTE-LAA.

For Transmission Modes other than mode 10 (e.g., for TM 3 or 4), there may not be any available fields that can be reused. In this situation, a new field may be introduced into the DCI . Values for the new field may be associated, by higher layer signaling, with the reference signals and the parameters corresponding to the transmission point.

Process 500 may further include determining time and frequency synchronization parameters based on the identified DRS (block 520). For instance, UE 255 may use the identified DRS to obtain the timing and frequency synchronization parameters.

Process 500 may further include receiving, based on the determined time and frequency synchronization parameters, downlink data from the transmission point (block 530). For instance, the PDSCH may be decoded and the downlink data, for UE 255, obtained. In decoding the PDSCH, time and frequency compensation may be applied in accordance with the obtained time and frequency synchronization parameters. A third example embodiment, relating to dynamic point selection for LTE-LAA, will next be described with reference to Fig. 6. Fig. 6 is a flowchart illustrating an example process 600 relating to the scheduling of transmission points for LTE-LAA in which the scheduling is performed using a self-scheduling mechanism in the unlicensed spectrum. Process 600 may be performed by, for example, UE 255.

Process 600 may include receiving, from the network, an indication of transmission points to monitor (block 610). The indication of transmission points to monitor may be received via licensed or unlicensed frequency bands. In one implementation, reception of the

transmission points to monitor may be performed relatively infrequently. The reception of the indication of the transmission points to monitor can be implemented as specific values for one or more parameters. For example, specific cell identifiers (IDs), virtual IDs, scrambling identifiers for modulation of reference signals, or other values may be received by UE 255.

Process 600 may further include monitoring received PDSCHs for an initial reference signal (block 620). UE 255 may receive PDSCH transmissions from multiple transmission points. In this embodiment, the transmission points may structure the PDSCH to begin with an initial reference signal that includes timing and frequency synchronization information. The initial reference signal may additionally include identification information, such as a cell ID, a virtual ID, a scrambling ID, or other identification information. The identification information may be used to identify the transmission point to UE 255.

When the initial reference signal includes transmission point identification information corresponding to one that is to be monitored (e.g., as received in block 610), UE 255 may extract the timing and frequency synchronization parameters from the initial reference signal (block 630). UE 255, when it receives a PDSCH, may examine the initial reference signal to determine whether the identification information in the initial reference signal matches the information relating to the received indication of the transmission points to monitor. For example, UE 255 may determine if the initial reference signal includes a cell ID that matches a cell ID that was received by the UE in block 610. When it does, UE 255 may extract the timing and frequency synchronization parameters from the initial reference signal.

Process 600 may further include using the extracted timing and frequency

synchronization parameters to demodulate control channel transmissions and obtain data channel (e.g., PDSCH) scheduling information (block 640). In one implementation, the

EPDCCH may be demodulated, using the timing and frequency synchronization parameters. The EPDCCH may include scheduling information relating to the UE. For example, the scheduling information may include resource elements, in the PDSCH, that are assigned to the UE. The UE may obtain, based on the scheduling information, the downlink data from the PDSCH (block 650).

As used herein, the term "circuitry" or "processing 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.

Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. Fig. 7 illustrates, for one embodiment, example components of an electronic device 700. In embodiments, the electronic device 700 may be a user equipment UE, an eNB, a transmission point, or some other appropriate electronic device. In some embodiments, the electronic device 700 may include application circuitry 702, baseband circuitry 704, Radio Frequency (RF) circuitry 706, front-end module (FEM) circuitry 708 and one or more antennas 760, coupled together at least as shown.

Application circuitry 702 may include one or more application processors. For example, the application circuitry 702 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 and/or may include memory/storage, such as storage medium 703, and may be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system. In some

implementations, storage medium 703 may include a non-transitory computer-readable medium. Application circuitry 702 may, in some embodiments, connect to or include one or more sensors, such as environmental sensors, cameras, etc.

Baseband circuitry 704 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 704 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 706 and to generate baseband signals for a transmit signal path of the RF circuitry 706. Baseband processing circuitry 704 may interface with the application circuitry 702 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 706. For example, in some embodiments, the baseband circuitry 704 may include a second generation (2G) baseband processor 704a, third generation (3G) baseband processor 704b, fourth generation (4G) baseband processor 704c, and/or other baseband processor(s) 704d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 7G, etc.). The baseband circuitry 704 (e.g., one or more of baseband processors 704a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 706. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some implementations, baseband circuitry 604 may be associated with storage medium 603 or with another storage medium.

In embodiments where the electronic device 704 is implemented in, incorporates, or is otherwise part of an LTE-LAA transmission point, the baseband circuitry 104 may be to:

identify one or more parameters related to the LTE-LAA transmission point, wherein the LTE- LAA transmission point is in a network that includes a plurality of LTE-LAA transmission points, respective LTE-LAA transmission points having respective parameters; and identify, based on a listen-before-talk (LBT) procedure related to identification of channel occupancy status of respective LTE-LAA transmission points in the plurality of LTE-LAA transmission points that the LTE-LAA transmission point has an un-occupied channel. RF circuitry 706 may be to transmit a signal based on the identification.

In some embodiments, modulation/demodulation circuitry of the baseband circuitry 704 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 704 may include convolution, tail-biting convolution, turbo, Viterbi, and/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. In some embodiments, the baseband circuitry 704 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 704e of the baseband circuitry 704 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 704f. The audio DSP(s) 704f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments.

Baseband circuitry 704 may further include memory/storage 704g. The memory/storage 704g may be used to load and store data and/or instructions for operations performed by the processors of the baseband circuitry 704. Memory/storage 704g may particularly include a non- transitory memory. Memory/storage for one embodiment may include any combination of suitable volatile memory and/or non-volatile memory. The memory/storage 704g may include any combination of various levels of memory/storage including, but not limited to, read-only memory (ROM) having embedded software instructions (e.g., firmware), random access memory (e.g., dynamic random access memory (DRAM)), cache, buffers, etc. The

memory/storage 704g may be shared among the various processors or dedicated to particular processors.

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 704 and the application circuitry 702 may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 704 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 704 may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/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 704 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry 706 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 706 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 706 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 708 and provide baseband signals to the baseband circuitry 704. RF circuitry 706 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 704 and provide RF output signals to the FEM circuitry 708 for transmission.

In some embodiments, the RF circuitry 706 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 706 may include mixer circuitry 706a, amplifier circuitry 706b and filter circuitry 706c. The transmit signal path of the RF circuitry 706 may include filter circuitry 706c and mixer circuitry 706a. RF circuitry 706 may also include synthesizer circuitry 706d for synthesizing a frequency for use by the mixer circuitry 706a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 706a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 708 based on the synthesized frequency provided by synthesizer circuitry 706d. The amplifier circuitry 706b may be configured to amplify the down-converted signals and the filter circuitry 706c 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 704 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 706a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 706a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 706d to generate RF output signals for the FEM circuitry 708. The baseband signals may be provided by the baseband circuitry 704 and may be filtered by filter circuitry 706c. The filter circuitry 706c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 706a of the receive signal path and the mixer circuitry 706a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 706a of the receive signal path and the mixer circuitry 706a 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 706a of the receive signal path and the mixer circuitry 706a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 706a of the receive signal path and the mixer circuitry 706a of the transmit signal path may be configured for super-heterodyne operation.

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 706 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 704 may include a digital baseband interface to communicate with the RF circuitry 706.

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.

In some embodiments, the synthesizer circuitry 706d may be a fractional-N synthesizer or a fractional N N+6 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 706d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

The synthesizer circuitry 706d may be configured to synthesize an output frequency for use by the mixer circuitry 706a of the RF circuitry 706 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 706d may be a fractional N/N+6 synthesizer.

In some embodiments, frequency input may be provided by a voltage-controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 704 or the applications processor 702 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 702.

Synthesizer circuitry 706d of the RF circuitry 706 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+6 (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.

In some embodiments, synthesizer circuitry 706d 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 706 may include an IQ/polar converter.

FEM circuitry 708 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 760, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 706 for further processing. FEM circuitry 708 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 706 for transmission by one or more of the one or more antennas 760.

In some embodiments, the FEM circuitry 708 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 a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 706). The transmit signal path of the FEM circuitry 708 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 706), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 760.

In some embodiments, the electronic device 700 may include additional elements such as, for example, memory/storage, display, camera, sensors, and/or input/output (I/O) interface. In some embodiments, the electronic device of Fig. 7 may be configured to perform one or more methods, processes, and/or techniques such as those described herein.

A number of examples, relating to implementations of the techniques described above, will next be given.

In a first example, a network device to coordinate LAA transmission may include circuitry to: receive indications, from a plurality of LAA transmission points, of a channel occupancy status of an unlicensed frequency channel associated with the plurality of LAA transmission points; dynamically select a transmission point, for a particular UE and from the plurality of LAA transmission points, based on the received indications of channel occupancy status; and forward downlink data, destined for the particular UE, to the selected LAA transmission point.

In example 2, the subject matter of example 1 may include wherein the channel occupancy status is determined, by the LAA transmission points, using a Listen Before Talk (LBT) procedure.

In example 3, the subject matter of example 1 or in any of the previous examples, the circuitry may further be to configure parameters, for two or more of the plurality of transmission points, relating to dynamic selection of the two or more of the plurality of the transmission points.

In example 4, the subject matter of example 1 or in any of the previous examples, the dynamic selection of the transmission point may include selecting the transmission point as a transmission point, from the plurality of LAA transmission points, in which the channel occupancy status is unoccupied.

In example 6, the subject matter of example 1 or in any of the previous examples, wherein the circuitry further includes a Radio Frequency (RF) circuitry, front-end module (FEM) circuitry, and one or more antennas to forward the downlink data; and baseband circuitry or application circuitry to receive the indications and dynamically select the transmission points.

In a sixth example, a computer readable medium containing program instructions for causing one or more processors to: receive indications, from a plurality of transmission points, of a channel occupancy status of an unlicensed frequency channel associated with the transmission points; dynamically select a transmission point, for a particular UE and from the plurality of transmission points, based on the received indications of channel occupancy status indicating that the unlicensed frequency channel, at the selected transmission point, is not occupied; and forward downlink data, destined for the particular UE, to the selected

transmission point.

In example 7, the subject matter of example 6 may further include wherein the channel occupancy status maybe determined, by the transmission points, using a Listen Before Talk (LBT) procedure.

In example 8, the subject matter of example 6, or any of the previous examples, the computer readable medium may additionally include program instructions for causing the one or more processors to: configure parameters, for two or more of the plurality of transmission points, relating to dynamic selection of the two or more of the plurality of the transmission points.

In example 9, the subject matter of example 1 or 6, or any other of the previous examples, carrier aggregation may be used based on the unlicensed frequency channel and a licensed frequency channel.

In example 10, the subject matter of example 1 or 6, or any other of the previous examples, the plurality of transmission points may include LTE-LAA transmission points.

In example 1 1 , the subject matter of example 1 or 6, or any other of the previous examples, the channel occupancy status maybe determined by comparing energy of the received signal, on the unlicensed frequency channel, with a threshold value.

In example 12, the subject matter of example 3 or 8, or any other of the previous examples, the parameters correspond to the Physical Downlink Shared Channel (PDSCH) parameters.

In example 13, the subject matter of example 1 or 6, or any other of the previous examples, may further include forwarding downlink data may be transmitted as a Physical

Downlink Shared Channel (PDSCH) transmission or as an Enhanced Physical Downlink Control Channel (EPDCCH) transmission.

In a 14th example a UE may include circuitry to receive scheduling information, via a licensed carrier, indicating a particular transmission point, of a plurality of transmission points, that the UE is to use to receive downlink data via an unlicensed carrier; determine timing and frequency synchronization parameters for the particular transmission point; and receive downlink data, from the particular transmission point, using the determined timing and frequency synchronization parameters.

In example 15, the subject matter of example 14 may further include the scheduling information includes Physical Downlink Shared Channel (PDSCH) resource elements that the UE is to use to receive the downlink data via the unlicensed carrier.

In example 16, the subject matter of example 15, or any other of the previous examples, may further include wherein the timing and frequency synchronization parameters include timing and frequency parameters obtained from a Demodulation Reference Signal (DM-RS) transmitted by the particular transmission point.

In example 17, the subject matter of example 15, or any other of the previous examples, may further include wherein the scheduling information includes an implicit indication of the particular transmission point. In example 18, the subject matter of claim 14, or any of the previous examples, may further include wherein the implicit indication of the particular transmission point includes an index value that refers to a Discovery Reference Signal (DRS) transmitted by the particular transmission point.

In example 19, the subject matter of claim 18, may further include wherein the DRS is used to obtain the timing and frequency synchronization parameters.

In a 20th example, a UE may comprise circuitry to: receive, via a radio interface, an indication of a plurality of LTE-LAA transmission points that the UE is to monitor for potential downlink data; receive, via an unlicensed frequency channel, a plurality of PDSCH

transmissions, from a plurality of the LTE-LAA transmission points; determine, based on an initial reference signal included in the received PDSCH transmissions, whether a particular one of the plurality of PDSCH transmissions corresponds to one of the plurality of the LTE-LAA transmission points; and receive downlink data, from the particular LTE-LAA transmission point and when the particular one of the plurality of PDSCH transmissions corresponds to one of the plurality of the LTE-LAA transmission points, from the PDSCH transmissions.

In example 21 , the subject matter of example 20, may further include wherein the circuitry is further to: extract, when the particular one of the plurality of PDSCH transmissions corresponds to one of the plurality of the LTE-LAA transmission points, timing and frequency synchronization parameters from the initial reference signal.

In example 22, the subject matter of example 21 , or any of the previous examples, may further include wherein the circuitry is further to: use the obtained timing and frequency synchronization parameters to demodulate a control channel to obtain scheduling information, for the UE, and relating to the obtaining of the downlink data from the PDSCH transmissions.

In example 23, the subject matter of example 21 , may further include wherein the indication of the plurality of LTE-LAA transmissions points includes cell identifier (ID) values.

In example 24, the subject matter of example 14 or 20, or any of the previous examples, may further include wherein the carrier aggregation is performed, at the UE, based on the unlicensed frequency channel and based on a licensed frequency channel.

In a 25th example, a UE device may comprise: means for receiving scheduling information, via a licensed carrier, indicating a particular transmission point, of a plurality of transmission points, that the UE is to use to receive downlink data via an unlicensed carrier; means for determining timing and frequency synchronization parameters for the particular transmission point; and means for receiving downlink data, from the particular transmission point, using the determined timing and frequency synchronization parameters.

In a 26th example, the subject matter of example 25, may further include wherein the scheduling information includes PDSCH resource elements that the UE is to use to receive the downlink data via the unlicensed carrier.

In example 27, the subject matter of example 26, or any of the previous examples, may further include wherein the timing and frequency synchronization parameters include timing and frequency parameters obtained from a DM-RS transmitted by the particular transmission point.

In example 28, the subject matter of example 25, or any of the previous examples, wherein the scheduling information includes an implicit indication of the particular transmission point.

In example 29, the subject matter of example 25, or any of the previous examples, wherein the implicit indication of the particular transmission point includes an index value that refers to a Discovery Reference Signal (DRS) transmitted by the particular transmission point.

In example 30, the subject matter of example 25, or any of the previous examples, wherein the DRS is used to obtain the timing and frequency synchronization parameters.

In the preceding specification, various embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.

For example, while series of signals have been described with regard to Figs. 4-7, the order of the signals may be modified in other implementations. Further, non-dependent signals may be performed in parallel.

It will be apparent that example aspects, as described above, may be implemented in many different forms of software, firmware, and hardware in the implementations illustrated in the figures. The actual software code or specialized control hardware used to implement these aspects should not be construed as limiting. Thus, the operation and behavior of the aspects were described without reference to the specific software code— it being understood that software and control hardware could be designed to implement the aspects based on the description herein.

Further, certain portions may be implemented as "logic" that performs one or more functions. This logic may include hardware, such as an application-specific integrated circuit ("ASIC") or a field programmable gate array ("FPGA"), or a combination of hardware and software.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the descriptions herein. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification.

No element, act, or instruction used in the present application should be construed as critical or essential unless explicitly described as such. An instance of the use of the term "and," as used herein, does not necessarily preclude the interpretation that the phrase "and/or" was intended in that instance. Similarly, an instance of the use of the term "or," as used herein, does not necessarily preclude the interpretation that the phrase "and/or" was intended in that instance. Also, as used herein, the article "a" is intended to include one or more items, and may be used interchangeably with the phrase "one or more." Where only one item is intended, the terms "one," "single," "only," or similar language is used.