HIGH SPEED DEPLOYMENTS

RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application No. 62/378,060, which was filed on August 22, 2016, the contents of which are hereby incorporated by reference as though fully set forth herein.

BACKGROUND

High-mobility scenarios, e.g., high-speed train (HST) and vehicle-to-vehicle (V2V) scenarios, are expected to be typical scenarios for fifth generation (5G) wireless communication systems. HST scenarios, in particular, can be particularly challenging due to the fact that train speed can exceed 250 km/h.

Three different types of wireless networks may be used to provide coverage to User Equipment (UE) in HST scenarios, including: (1) a Single Frequency Network (SFN) with bidirectional remote radio heads (RRHs) or base stations (BSs); (2) a SFN with uni -directional RRHs or BSs; and (3) Non-SFN networks, such as a wireless network using an Extended Typical Urban (ETU) channel model. With all of these types of networks, a UE may experience throughput performance degradation due to the high speeds. For example, a UE using a legacy channel estimation approach ("legacy UE") may experience a performance degradation of about 30% when it is running at a speed of 350km/h in a bidirectional SFN. In order to maintain satisfactory throughput performance for high speed scenarios, various modified channel estimation approaches at the UE side have been designed.

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 illustrates an architecture of a system of a network in accordance with some embodiments;

Figs. 2A and 2B are diagrams illustrating portions of a RAN that are deployed, by a network operator, to provide coverage for HSTs;

Fig. 3 is a flowchart illustrating an example process for performing channel estimation by a UE; Fig. 4 is a flowchart illustrating an example process for performing channel estimation by a UE according to a second embodiment;

Fig. 5 is a flowchart illustrating an example process for implementing a SFN network;

Fig. 6 illustrates example components of a device in accordance with some

embodiments;

Fig. 7 illustrates example interfaces of baseband circuitry in accordance with some embodiments; and

Fig. 8 is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein.

DETAILED DESCRIPTION OF PREFERRED EMBODFMENTS

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 is defined by the appended claims and their equivalents.

Techniques described herein relate to methods and devices to enable a UE to determine when the UE is in a coverage area designed for HSTs. In particular, network-assisted signaling may be used to indicate, to a UE, when the UE enters or leaves a HST coverage area. The UE may respond by performing (or ceasing to perform) UE speed estimation, called blind detection herein, to estimate a speed of the UE (i.e., a mobility status of the UE). The UE may use its mobility status to determine a channel estimation approach to use.

In some implementations, the network-assisted signaling, in addition to indicating that a UE is in an HST coverage area, may indicate the type of network coverage. For example, the HST coverage may be implemented using uni-directional Single Frequency Network (SFN) base stations, bi-directional SFN base stations, or non-SFN (legacy) base stations. The type of network coverage can be additionally used by the UE when determining an appropriate channel estimation approach to use.

Fig. 1 illustrates an architecture of a system 100 of a network in accordance with some embodiments. The system 100 is shown to include a user equipment (UE) 101 and a UE 102.

The UEs 101 and 102 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.

The UEs 101 and 102 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) 110— the RAN 110 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 101 and 102 utilize connections 103 and 104, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections 103 and 104 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.

The RAN 110 can include one or more access nodes that enable the connections 103 and 104. 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 110 may include one or more RAN nodes for providing macrocells, e.g., macro RAN node 111, and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node 112. In some embodiments, a RAN node may be implemented as or include one or more Remote Radio Heads (RRHs).

In some embodiments, as will be described in more detail below, RAN nodes 111 and

112 may particularly include base stations that are deployed, by the operator of the wireless network, to provide coverage to UEs that are anticipated as traveling at high speeds. For example, a HST deployment may include a number of RAN nodes that are deployed along the train tracks to cover the train routes. The RAN nodes that are part of the HST deployment may be explicitly designed to provide optimum coverage to UEs that are on a HST. Example coverage scenarios for the HST routes will be described in more detail below with reference to Figs. 2 A and 2B.

Any of the RAN nodes 111 and 112 can terminate the air interface protocol and can be the first point of contact for the UEs 101 and 102. In some embodiments, any of the RAN nodes 111 and 112 can fulfill various logical functions for the RAN 110 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.

In accordance with some embodiments, the UEs 101 and 102 can be configured to communicate using Orthogonal Frequency -Division Multiplexing (OFDM) communication signals with each other or with any of the RAN nodes 111 and 112 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.

In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 111 and 112 to the UEs 101 and 102, 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.

The physical downlink shared channel (PDSCH) may carry user data and higher-layer signaling to the UEs 101 and 102. 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 101 and 102 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 102 within a cell) may be performed at any of the RAN nodes 111 and 112 based on channel quality information fed back from any of the UEs 101 and 102. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs 101 and 102.

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).

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.

The RAN 110 is shown to be communicatively coupled to a core network (CN) 120— via an SI interface 113. In embodiments, the CN 120 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 113 is split into two parts: the Sl-U interface 114, which carries traffic data between the RAN nodes 111 and 112 and the serving gateway (S-GW) 122, and the SI -mobility management entity (MME) interface 115, which is a signaling interface between the RAN nodes 111 and 112 and MMEs 121.

In this embodiment, the CN 120 comprises the MMEs 121, the S-GW 122, the Packet Data Network (PDN) Gateway (P-GW) 123, and a home subscriber server (HSS) 124. The MMEs 121 may be similar in function to the control plane of legacy Serving General Packet

Radio Service (GPRS) Support Nodes (SGSN). The MMEs 121 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 124 may comprise a database for network users, including subscription-related information to support the network entities' handling of communication sessions. The CN 120 may comprise one or several HSSs 124, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 124 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc.

The S-GW 122 may terminate the SI interface 113 towards the RAN 110, and routes data packets between the RAN 110 and the CN 120. In addition, the S-GW 122 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.

The P-GW 123 may terminate an SGi interface toward a PDN. The P-GW 123 may route data packets between the EPC network 123 and external networks such as a network including the application server 130 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 125. Generally, the application server 130 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 123 is shown to be communicatively coupled to an application server 130 via an IP communications interface 125. The application server 130 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 101 and 102 via the CN 120.

The P-GW 123 may further be a node for policy enforcement and charging data collection. Policy and Charging Enforcement Function (PCRF) 126 is the policy and charging control element of the CN 120. 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 126 may be communicatively coupled to the application server 130 via the P-GW 123. The application server 130 may signal the PCRF 126 to indicate a new service flow and select the appropriate Quality of Service (QoS) and charging parameters. The PCRF 126 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 130. Figs. 2 A and 2B are diagrams illustrating portions of a RAN 110 that are deployed, by a network operator, to provide coverage for HSTs. In particular, a number of RAN nodes are illustrated. In some embodiments, RAN nodes may be implemented as RRHs of one or more eNodeBs.

As shown in Fig. 2 A, four RAN nodes are illustrated, labeled as RAN nodes 205-1 and

205-2, and 210-1 and 210-2. RAN nodes 210 may be deployed to provide coverage along the length of a HST track and RAN nodes 205 are legacy nodes that are not capable of providing optimized coverage for HST scenarios. RAN nodes 210-1 and 210-2 may use a single, coordinated downlink frequency (SFN) and be either bi-direction or uni-directional. In this particular example, RAN nodes 210 are illustrated as being bi-directional, which may refer to the nodes providing downlink coverage both when the train is approaching the node and when the train is moving away from the node (i.e., as shown in Fig. 2A via arrows, nodes 210-1 and 210-2 provide downlink data to both the left and the right of the node).

In the example of Fig. 2B, RAN nodes 210, instead of providing bi-directional coverage, are illustrated as providing uni-directional coverage. For example, nodes 210 may be SFN nodes that provide downlink coverage in one direction relative to the movement of the HST. Thus, RAN nodes 210 may only provide coverage to UEs that have passed the node and are moving away from the node. For UEs going in the opposite direction, the same RAN nodes may provide coverage for UEs that are approaching the RAN node but will not be able to provide coverage when the UE has passed the RAN node. In Fig. 2B, RAN nodes 210 are illustrated as providing coverage to UEs that are to the right of the RAN node (i.e., moving away from the RAN node from the perspective of the direction of the illustrated trains).

Fig. 3 is a flowchart illustrating an example process 300 for performing channel estimation by a UE. Process 300 may be performed by UE 101 or 102 (referred to as UE 101 in the description that follows).

Process 300 may include receiving network signaling that indicates the UE is in a HST coverage area (block 310). In one embodiment, RAN nodes 210 may signal, via a single bit, that RAN node 210 is a HST coverage node. A number of different potential mechanisms can be used to transmit the signaling bit. For example, the signaling bit may be transmitted via Radio Resource Control (RRC) signaling, and may be implemented using a newly defined Information Element (IE) or implemented using an existing IE. Alternatively or additionally, higher layer signaling may be used. The signaling bit may be periodically transmitted by RAN node 210, transmitted as part of a handover procedure, and/or transmitted as control information. Process 300 may further include performing, in response to the network signaling indicating that the UE is in a HST coverage area, blind detection to determine a mobility state of the UE (block 320). As previously mentioned, blind detection may refer to the UE estimating a current speed of the UE. In one implementation, the estimation may be a coarse estimation in which the UE determines if the UE is traveling above a threshold speed or not. In one embodiment, the blind detection can include the UE using a cross product of Cell Specific Reference Signals (CRS) to estimate a frequency offset. The frequency offset may be a real-time frequency offset based on Doppler shift due to the speed of the UE.

In some embodiments, the blind detection may also be used to provide an indication of the type of network that is currently providing coverage to the UE. For example, the frequency offset estimation output of the CRS cross product may change based on the network coverage type as follows:

• In a first scenario, in which the UE is not in a HST coverage area, the frequency offset may be approximately zero Hz. This may be due to the fact that there can be a lot of multi-paths in ETU channels and there is theoretically no single strong path. Moreover, in this scenario, the train speed (or Max Doppler shift)) can be monitored by a real-time max Doppler shift estimator.

• In a second scenario, in which the UE is in a HST coverage area with bi-directional RAN nodes, and when the train is moving at a high speed, the frequency offset may be measured as two large estimated frequency offsets that appear periodically with relatively equal value for opposite signs (i.e., plus and minus). When the train is moving at a low speed, then two frequency offsets may be measured as two small frequency offsets. The two frequency offsets are received because the train receives two major paths from the RAN nodes (i.e., the one in front and the one behind).

• In a third scenario, in which the UE is in a HST coverage area with uni-directional RAN nodes, a single dominant estimated frequency offset may be measured. This may be due to the main-lobe effect of the uni-directional node.

Process 300 may further include, when the UE is in a high-speed mobility state (block 330 - Yes), performing channel estimation using techniques for estimating channel parameters under high-speed conditions (block 340). As the radio signal propagates through a medium (called a channel), the signal can get distorted and/or various noise added to the signal. To properly decode the received signal to remove the distortion and noise due to the channel, a first step may be to figure out the characteristics of the channel that the signal has gone through. The techniques to characterize the channel is referred to as "channel estimation." Channel parameters that are obtained from the channel estimation may be used for diversity combining, coherent detection, and decoding in the receiver. It is known to use different channel estimation techniques for different environments, such as channel estimation techniques for high-speed (i.e., high-mobility) UEs that are traveling through a SFN.

Process 300 may further include, when the UE is not in a high-speed mobility state (block 330 - No), performing channel estimation using techniques for estimating channel parameters under normal (i.e., non-high speed) conditions (block 350). These channel estimation techniques may be techniques that are used to estimate the channel parameters for a UE that is traversing an SFN at low (normal) speed.

Process 300 may further include communicating using the estimated channel parameters (block 360). In this manner, depending on the signaling obtained from the network, a UE may know when blind detection is needed to determine whether the UE is traveling at a high speed. The blind detection process can consume battery, and accordingly, via the network signaling, a UE may only perform the blind detection process when it is in the coverage area of a HST network. Further, the channel parameter estimation may be performed as both a function of the UE's mobility state (speed) and a function of whether the UE is in a HST coverage area.

Fig. 4 is a flowchart illustrating an example process 400 for performing channel estimation by a UE according to a second embodiment. Process 400 may be performed by UE 101 or 102.

Process 400 may include receiving network signaling that indicates the UE is in a HST coverage area (block 410) and network signaling that indicates a type of network of the HST network (block 415). For example, in this embodiment, in addition to signaling an HST coverage area, the signaling from a particular RAN node may indicate whether the RAN node is a bi-directional SFN or a uni-directional SFN. Accordingly, UE 101 may be provided with additional information which may be used to enhance the blind detection and/or the channel estimation processes. The UE, such as a baseband processor of the UE, may decode the signaling.

Although blocks 410 and 415 were described as two separate blocks, in practice, the operations of blocks 410 and 415 may be performed using a single signaling field in a message transmitted by RAN node 210. For example, a HST signaling field may be a two-bit field in which one combination of the two bits indicates a SFN bi-directional network and another combination of the two bits indicates a SFN uni-directional network. In some implementations, the presence of a non-SFN (i.e., non-HST network) may also be signaled. Process 400 may further include performing, in response to the network signaling, blind detection to determine a mobility state of the UE (block 420). Process 400 may further include, when the UE is in a high-speed mobility state (block 430 - Yes), performing channel estimation using techniques for estimating channel parameters under high-speed conditions (block 440). When the UE is not in a high-speed mobility state (block 430 - No), process 400 may include performing channel estimation using techniques for estimating channel parameters under normal (i.e., non-high speed) conditions (block 450) Process 400 may further include communicating using the estimated channel parameters (block 460). In general, the operation of blocks 420-460 may be similar to the operation of blocks 320-360, respectively, except that UE 101 may use the information relating to the HST network type to assist in blind detection and/or channel estimation.

Fig. 5 is a flowchart illustrating an example process 500 for implement a SFN network. Process 500 may be performed by RAN node 210.

Process 500 may include transmitting signaling information (block 510). For example, the signaling information can be a single signal bit that is broadcast as part of the control channel. The signal bit may be transmitted via Radio Resource Control (RRC) signaling, and may be implemented using a newly defined Information Element (IE) or implemented using an existing IE. Alternatively or additionally, higher layer signaling may be used. The signaling bit may be periodically transmitted by RAN node 210, transmitted as part of a handover procedure, and/or transmitted in some other manner. In some embodiments, as was discussed above, the signaling information can include more than one bit of information and may indicate the type of the HST network (e.g., uni-directional or bi-directional).

Process 500 may further include communicating with UEs using SFN coverage for highspeed conditions (block 520). RAN node 210 may implement control and traffic channels with the UE to implement the RAN interface.

Fig. 6 illustrates example components of a device 600 in accordance with some embodiments. In some embodiments, the device 600 may include application circuitry 602, baseband circuitry 604, Radio Frequency (RF) circuitry 606, front-end module (FEM) circuitry 608, one or more antennas 610, and power management circuitry (PMC) 612 coupled together at least as shown. The components of the illustrated device 600 may be included in a UE or a RAN node. In some embodiments, the device 600 may include less elements (e.g., a RAN node may not utilize application circuitry 602, and instead include a processor/controller to process IP data received from an EPC). In some embodiments, the device 600 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).

The application circuitry 602 may include one or more application processors. For example, the application circuitry 602 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 600. In some embodiments, processors of application circuitry 602 may process IP data packets received from an EPC.

The baseband circuitry 604 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 604 may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry 606 and to generate baseband signals for a transmit signal path of the RF circuitry 606. Baseband processing circuity 604 may interface with the application circuitry 602 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 606. For example, in some embodiments, the baseband circuitry 604 may include a third generation (3G) baseband processor 604 A, a fourth generation (4G) baseband processor 604B, a fifth generation (5G) baseband processor 604C, or other baseband processor(s) 604D 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 604 (e.g., one or more of baseband processors 604 A-D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 606. In other

embodiments, some or all of the functionality of baseband processors 604 A-D may be included in modules stored in the memory 604G and executed via a Central Processing Unit (CPU) 604E. 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 604 may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 604 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.

In some embodiments, the baseband circuitry 604 may include one or more audio digital signal processor(s) (DSP) 604F. The audio DSP(s) 604F 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 604 and the application circuitry 602 may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 604 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 604 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 604 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

Baseband circuitry 604 may also include an interface to RF circuitry 606.

RF circuitry 606 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 606 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 606 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 608 and provide baseband signals to the baseband circuitry 604. RF circuitry 606 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 604 and provide RF output signals to the FEM circuitry 608 for transmission.

In some embodiments, the receive signal path of the RF circuitry 606 may include mixer circuitry 606a, amplifier circuitry 606b and filter circuitry 606c. In some embodiments, the transmit signal path of the RF circuitry 606 may include filter circuitry 606c and mixer circuitry 606a. RF circuitry 606 may also include synthesizer circuitry 606d for synthesizing a frequency for use by the mixer circuitry 606a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 606a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 608 based on the synthesized frequency provided by synthesizer circuitry 606d. The amplifier circuitry 606b may be configured to amplify the down-converted signals and the filter circuitry 606c 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 604 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 606a 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 606a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 606d to generate RF output signals for the FEM circuitry 608. The baseband signals may be provided by the baseband circuitry 604 and may be filtered by filter circuitry 606c.

In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a 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 606a of the receive signal path and the mixer circuitry 606a may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a 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 606 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 604 may include a digital baseband interface to communicate with the RF circuitry 606.

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 606d 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 606d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

The synthesizer circuitry 606d may be configured to synthesize an output frequency for use by the mixer circuitry 606a of the RF circuitry 606 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 606d may be a fractional N/N+l 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 604 or the applications processor 602 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 602.

Synthesizer circuitry 606d of the RF circuitry 606 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 (DP A). 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.

In some embodiments, synthesizer circuitry 606d 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 606 may include an IQ/polar converter.

FEM circuitry 608 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 610, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry

606 for further processing. FEM circuitry 608 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 606 for transmission by one or more of the one or more antennas 610. In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry 606, solely in the FEM 608, or in both the RF circuitry 606 and the FEM 608.

In some embodiments, the FEM circuitry 608 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 606). The transmit signal path of the FEM circuitry 608 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 606), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 610).

In some embodiments, the PMC 612 may manage power provided to the baseband circuitry 604. In particular, the PMC 612 may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMC 612 may often be included when the device 600 is capable of being powered by a battery, for example, when the device is included in a UE. The PMC 612 may increase the power conversion efficiency while providing desirable implementation size and heat dissipation characteristics.

While Fig. 6 shows the PMC 612 coupled only with the baseband circuitry 604.

However, in other embodiments, the PMC 6 12 may be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, application circuitry 602, RF circuitry 606, or FEM 608.

In some embodiments, the PMC 612 may control, or otherwise be part of, various power saving mechanisms of the device 600. For example, if the device 600 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 600 may power down for brief intervals of time and thus save power.

If there is no data traffic activity for an extended period of time, then the device 600 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 600 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 600 may not receive data in this state, in order to receive data, it must transition back to RRC Connected state. 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.

Processors of the application circuitry 602 and processors of the baseband circuitry 604 may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry 604, alone or in combination, may be used execute Layer 3, Layer 2, or Layer 1 functionality, while processors of the application circuitry 604 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.

Fig. 7 illustrates example interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry 704 of Fig. 7 may comprise processors 704A-704E and a memory 704G utilized by said processors. Each of the processors 704A-704E may include a memory interface, 704A-704E, respectively, to send/receive data to/from the memory 704G.

The baseband circuitry 704 may further include one or more interfaces to

communicatively couple to other circuitries/devices, such as a memory interface 712 (e.g., an interface to send/receive data to/from memory external to the baseband circuitry 704), an application circuitry interface 714 (e.g., an interface to send/receive data to/from the application circuitry 702 of Fig. 7), an RF circuitry interface 716 (e.g., an interface to send/receive data to/from RF circuitry 706 of Fig. 7), a wireless hardware connectivity interface 718 (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 720 (e.g., an interface to send/receive power or control signals to/from the PMC 712.

Fig. 8 is a block diagram illustrating components, according to some example

embodiments, able to read instructions from a machine-readable or computer-readable medium

(e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically, Fig. 8 shows a diagrammatic representation of hardware resources 800 including one or more processors (or processor cores) 810, one or more memory/storage devices 820, and one or more communication resources 830, each of which may be communicatively coupled via a bus 840. For embodiments where node virtualization (e.g., FV) is utilized, a hypervisor 802 may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources 800

The processors 810 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP) such as a baseband processor, an application specific integrated circuit (ASIC), a radio-frequency integrated circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, a processor 812 and a processor 814.

The memory/storage devices 820 may include main memory, disk storage, or any suitable combination thereof. The memory/storage devices 820 may include, but are not limited to any type of volatile or non-volatile memory such as dynamic random access memory

(DRAM), static random-access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), Flash memory, solid-state storage, etc.

The communication resources 830 may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices 804 or one or more databases 806 via a network 808. For example, the communication resources 830 may include wired communication components (e.g., for coupling via a Universal Serial Bus (USB)), cellular communication components, NFC components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components.

Instructions 850 may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors 810 to perform any one or more of the methodologies discussed herein. The instructions 850 may reside, completely or partially, within at least one of the processors 810 (e.g., within the processor's cache memory), the memory/storage devices 820, or any suitable combination thereof. Furthermore, any portion of the instructions 850 may be transferred to the hardware resources 800 from any combination of the peripheral devices 804 or the databases 806. Accordingly, the memory of processors 810, the memory/storage devices 820, the peripheral devices 804, and the databases 806 are examples of computer-readable and machine-readable media.

A number of examples, relating to implementations of the techniques described above, will next be given. In a first example, baseband circuitry for User Equipment (UE) may comprise a radio frequency (RF) interface; and one or more processors to: decode signaling, received via the RF interface and from a radio access network (RAN) node of a wireless cellular network, indicating whether the RAN node provides coverage for high-speed UEs; perform, when the decoded signaling indicates that the RAN node provides coverage for high-speed UEs, a mobility detection operation to detect a mobility state of the UE; communicate, using the RF interface, with the RAN node, based on the detected mobility state of the UE.

In example 2, the subject matter of example 1, wherein the mobility detection operation includes a blind detection operation to estimate a frequency offset with the RAN node.

In example 3, the subject matter of example 1, or any of the preceding examples, wherein the blind detection operation is based on a cross product of Cell Specific Reference Signals (CRS) received from the RAN node.

In example 4, the subject matter of examples 1 or 2, or any of the preceding examples, wherein the one or more processors are further to: estimate channel parameters, of a radio channel with the RAN node, using a channel estimation technique for high-speed UEs, when the mobility state of the UE indicates that the UE is moving at a high speed.

In example 5, the subject matter of example 1 or 4, or any of the preceding examples, wherein the blind detection operation is based on a cross product of Cell Specific Reference Signals (CRS) received from the RAN node.

In example 3, the subject matter of example 1, or any of the preceding examples, wherein the blind detection operation is based on a cross product of Cell Specific Reference Signals (CRS) received from the RAN node.

In example 6, the subject matter of example 1, or any of the preceding examples, wherein the one or more processors, when decoding the signaling, are further to: decode, based on a multi-bit signaling message, a type of the RAN node as: a bi-directional single frequency network (SFN) node, or a uni-directional SFN node.

In example 7, the subject matter of example 1, or any of the preceding examples, wherein the signaling is decoded as a single bit in a control message broadcast by the RAN node.

In an eighth example, User Equipment (UE) may comprise a computer-readable medium containing processing instructions; and one or more processors, to execute the processing instructions to: receive, from a radio access network (RAN) node of a wireless cellular network, a message indicating whether the RAN node is a single frequency network (SFN) node; perform, when the RAN node is a SFN node, a mobility detection operation to detect a mobility state of the UE; select, based on the determined mobility state of the UE and the indication of whether the RAN node is a SFN node, a channel estimation technique of a plurality of possible channel estimation techniques; and estimate channel parameters using the selected channel estimation technique; and communicate, with the RAN node, based on the estimated channel parameters.

In example 9, the subject matter of example 8, or any of the preceding examples, wherein the the mobility detection operation includes a blind detection operation to estimate a frequency offset with the RAN node.

In example 10, the subject matter of example 9, or any of the preceding examples, wherein the blind detection operation is based on a cross product of Cell Specific Reference Signals (CRS) received from the RAN node.

In example 11, the subject matter of examples 8 or 9, or any of the preceding examples, wherein the wherein when the detected mobility state of the UE indicates that the UE is moving at a high speed, the one or more processors are further to: select a channel estimation technique for a UE that is on a high-speed train (HST).

In example 12, the subject matter of example 8, or any of the preceding examples, wherein the message further indicates whether the RAN node is a bi-directional single frequency network (SFN) node or a uni-directional SFN node.

In example 13, the subject matter of example 8, or any of the preceding examples, wherein the signaling is decoded as a single bit in a control message broadcast by the RAN node.

In a 14 ^th example, a computer-readable medium contains program instructions for causing one or more processors to: decode signaling, received from a radio access network (RAN) node of a wireless cellular network, indicating whether the RAN node provides coverage for high-speed UEs; perform, when the decoded signaling indicates that the RAN node provides coverage for high-speed UEs, a mobility detection operation to detect a mobility state of the UE; refrain from performing, when the decoded signaling indicates that the RAN node does not provide coverage for high-speed UEs, the mobility detection operation; and communicate, with the RAN node, based on the detected mobility state of the UE.

In example 15, the subject matter of example 14, or any of the preceding examples, wherein the mobility detection operation includes a blind detection operation to estimate a frequency offset with the RAN node.

In example 16, the subject matter of example 15, or any of the preceding examples, wherein the blind detection operation is based on a cross product of Cell Specific Reference Signals (CRS) received from the RAN node. In example 17, the subject matter of examples 14 or 15, or any of the preceding examples, wherein the one or more processors are further to: estimate channel parameters, of a radio channel with the RAN node, using a channel estimation technique for high-speed UEs, when the mobility state of the UE indicates that the UE is moving at a high speed.

In example 18, the subject matter of examples 14 or 17, or any of the preceding examples, wherein the mobility state of the UE moving at high speed corresponds to a state in which the UE is in a high-speed train (HST).

In example 19, the subject matter of example 14, or any of the preceding examples, wherein the one or more processors, when decoding the signaling, are further to: decode, based on a multi-bit signaling message, a type of the RAN node as: a bi-directional single frequency network (SFN) node, or a uni-directional SFN node.

In example 20, the subject matter of example 14, or any of the preceding examples, wherein the signaling is decoded as a single bit in a control message broadcast by the RAN node.

In a 21 ^st example, a method, performed by User Equipment (UE), may comprise:

decoding signaling, received via the RF interface and from a radio access network (RAN) node of a wireless cellular network, indicating whether the RAN node provides coverage for highspeed UEs; performing, when the decoded signaling indicates that the RAN node provides coverage for high-speed UEs, a mobility detection operation to detect a mobility state of the UE; and communicating, with the RAN node, based on the detected mobility state of the UE.

In example 22, the subject matter of example 21, or any of the preceding examples, wherein the mobility detection operation includes a blind detection operation to estimate a frequency offset with the RAN node.

In example 23, the subject matter of example 22, or any of the preceding examples, wherein the blind detection operation is based on a cross product of Cell Specific Reference Signals (CRS) received from the RAN node.

In example 24, the subject matter of example 21 or 22, or any of the preceding examples, further comprising: estimating channel parameters, of a radio channel with the RAN node, using a channel estimation technique for high-speed UEs, when the mobility state of the UE indicates that the UE is moving at a high speed.

In example 25, the subject matter of examples 21 or 24, or any of the preceding examples, wherein the mobility state of the UE moving at high speed corresponds to a state in which the UE is in a high-speed train (HST). In example 26, the subject matter of example 21, or any of the preceding examples, wherein the decoding of the signaling further comprises: decoding, based on a multi-bit signaling message, a type of the RAN node as: a bi-directional single frequency network (SFN) node, or a uni-directional SFN node.

In example 27, the subject matter of example 21, or any of the preceding examples, wherein the signaling is decoded as a single bit in a control message broadcast by the RAN node.

In a 28 ^th example, User Equipment (UE) may comprise: means for decoding signaling, received from a radio access network (RAN) node of a wireless cellular network, indicating whether the RAN node provides coverage for high-speed UEs; means for performing, when the decoded signaling indicates that the RAN node provides coverage for high-speed UEs, a mobility detection operation to detect a mobility state of the UE; and means for communicating, using the RF interface, with the RAN node, based on the detected mobility state of the UE.

In example 29, the subject matter of example 28, or any of the preceding examples, wherein the mobility detection operation includes a blind detection operation to estimate a frequency offset with the RAN node.

In example 30, the subject matter of example 28, or any of the preceding examples, wherein the blind detection operation is based on a cross product of Cell Specific Reference

Signals (CRS) received from the RAN node.

In example 31, the subject matter of examples 28 or 30, or any of the preceding examples, further comprising: means for estimating channel parameters, of a radio channel with the RAN node, using a channel estimation technique for high-speed UEs, when the mobility state of the UE indicates that the UE is moving at a high speed.

In example 32, the subject matter of example 28 or 31, or any of the preceding examples, wherein the mobility state of the UE moving at high speed corresponds to a state in which the

UE is in a high-speed train (HST).

In example 33, the subject matter of example 28, or any of the preceding examples, further comprising: means for decoding a type of the RAN node as: a bi-directional single frequency network (SFN) node, or a uni-directional SFN node.

In example 34, the subject matter of example 28, or any of the preceding examples, wherein the signaling is decoded as a single bit in a control message broadcast by the RAN node.

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 and/or operations have been described with regard to Figs. 3-5, the order of the signals/operations 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.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to be limiting. 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.