Patent ID: 12207296

DETAILED DESCRIPTION

In some examples of wireless communication, a relay node may enable relay communication procedures, which may provide coverage, enhance throughput, or both, for a geographic area. For example, in a network based relay, a base station may communicate with a relay node via a backhaul link, and the relay node may communicate with a remote user equipment (UE) via an access link (e.g., a bidirectional wireless link). In an outband relay scenario, the access link and the backhaul link may operate in different carrier frequencies, and the relay node may simultaneously transmit and receive. However, in an inband relay node scenario, the backhaul link and the access link may be time division multiplexed (TDM) on the same carrier frequency.

In some examples, relay communication procedures may result in some constraints on communication. For instance, in some wireless communications systems (e.g., narrowband internet of things (NB-IoT), machine type communications (MTC), evolved MTC (eMTC), or the like), a UE may perform cross-subframe channel estimation for demodulation of downlink signals. However, when a relay node or a remote UE initiate or terminate relay transmissions on a channel, channel parameters may change suddenly and performance of some UEs may be affected based on poor channel estimation. To address cross-subframe channel estimation issues that arise when performing relay communications, a base station may configure a remote UE with a set of valid transmission time intervals (e.g., subframes) for downlink transmissions from the base station, and a relay node may configure the same remote UE with a set of valid TTIs (e.g., subframes) for relay transmissions from the relay node. The UE may thus determine a first set of TTIs for receiving downlink transmissions, a second set of TTIs for receiving relay transmissions, and a third set of subframes for receiving a downlink transmission that is multiplexed (e.g., via frequency division multiplexing (FDM)) with a relay transmission. Similarly, independent subframe sets may be allocated for uplink transmissions.

In some cases, if uplink synchronization is based on base station timing, then uplink signals from two UEs with uplink relaying may not be synchronized for arrival at the relay node. In such cases, uplink performance may be degraded (e.g., if a timing error is larger than the cyclic prefix). Thus, if a remote UE is close enough to the relay node with a small timing error, then the UE may be relayed (e.g., may participate in relay procedures). But, if a remote UE is too far away from the relay node and the large timing error degrades relay communications, then the UE may not be relayed (e.g., may not participate in relay procedures). A relay node may not be able to determine whether a remote UE is geographically located close enough to the relay node to perform relay communications. In such examples, the base station may configure the remote UE to transmit a random access transmission with an uplink timing advance value, so that the relay node can identify a transmission timing of the remote UE and determine whether the remote UE can be relayed. In some examples, the relay node may transmit a relay reference signal (e.g., a channel state information reference signal (CSI-RS)) or a synchronization signal not on the sync raster) to the remote UE for relay discovery. The remote UE may measure the reference signal receive power (RSRP) of the relay reference signal and may identify an estimated timing for the reference signal. If the estimated timing satisfies a timing threshold (e.g., is less than a cyclic prefix length) and if the RSRP satisfies a power threshold, then the UE may report to the base station that it is capable of relay procedures with the relay node, and may request downlink relaying via the relay node.

Aspects of the disclosure are initially described in the context of a wireless communications system. Aspects of the disclosure are further illustrated by and described with reference to timing schemes, transmission mode switching schemes, subframe allocations, and process flows. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to a non-transparent inband relay node in a single frequency network.

FIG.1illustrates an example of a wireless communications system100that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The wireless communications system100includes base stations105, UEs115, and a core network130. In some examples, the wireless communications system100may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system100may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

Base stations105may wirelessly communicate with UEs115via one or more base station antennas. Base stations105described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or giga-NodeB (either of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system100may include base stations105of different types (e.g., macro or small cell base stations). The UEs115described herein may be able to communicate with various types of base stations105and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station105may be associated with a particular geographic coverage area110in which communications with various UEs115is supported. Each base station105may provide communication coverage for a respective geographic coverage area110via communication links125, and communication links125between a base station105and a UE115may utilize one or more carriers. Communication links125shown in wireless communications system100may include uplink transmissions from a UE115to a base station105, or downlink transmissions from a base station105to a UE115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.

The geographic coverage area110for a base station105may be divided into sectors making up a portion of the geographic coverage area110, and each sector may be associated with a cell. For example, each base station105may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station105may be movable and therefore provide communication coverage for a moving geographic coverage area110. In some examples, different geographic coverage areas110associated with different technologies may overlap, and overlapping geographic coverage areas110associated with different technologies may be supported by the same base station105or by different base stations105. The wireless communications system100may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations105provide coverage for various geographic coverage areas110.

The term “cell” refers to a logical communication entity used for communication with a base station105(e.g., over a carrier), and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID)) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC), narrowband Internet-of-Things (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area110(e.g., a sector) over which the logical entity operates.

UEs115may be dispersed throughout the wireless communications system100, and each UE115may be stationary or mobile. A UE115may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE115may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a multimedia/entertainment device (e.g., a radio, a MP3 player, a video device, etc.), a camera, a gaming device, a navigation/positioning device (e.g., GNSS (global navigation satellite system) devices based on, for example, GPS (global positioning system), Beidou, GLONASS, or Galileo, a terrestrial-based device, etc., a tablet computer, a laptop computer, a personal computer, a netbook, a smartbook, a personal computer, a smart device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, virtual reality goggles, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet)), a drone, a robot/robotic device, a vehicle, a vehicular device, a meter (e.g., parking meter, electric meter, gas meter, water meter), a monitor, a gas pump, an appliance (e.g., kitchen appliance, washing machine, dryer), a location tag, a medical/healthcare device, an implant, a sensor/actuator, a display, or any other suitable device configured to communicate via a wireless or wired medium. In some examples, a UE115may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.

Some UEs115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station105without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs115may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging. In an aspect, techniques disclosed herein may be applicable to MTC or IoT UEs. MTC or IoT UEs may include MTC/enhanced MTC (eMTC, also referred to as CAT-M, Cat M1) UEs, NB-IoT (also referred to as CAT NB1) UEs, as well as other types of UEs. eMTC and NB-IoT may refer to future technologies that may evolve from or may be based on these technologies. For example, eMTC may include FeMTC (further eMTC), eFeMTC (enhanced further eMTC), mMTC (massive MTC), etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT), FeNB-IoT (further enhanced NB-IoT), etc.

Some UEs115may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously). In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs115include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications). In some cases, UEs115may be designed to support critical functions (e.g., mission critical functions), and a wireless communications system100may be configured to provide ultra-reliable communications for these functions.

In some cases, a UE115may also be able to communicate directly with other UEs115(e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). One or more of a group of UEs115utilizing D2D communications may be within the geographic coverage area110of a base station105. Other UEs115in such a group may be outside the geographic coverage area110of a base station105, or be otherwise unable to receive transmissions from a base station105. In some cases, groups of UEs115communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE115transmits to every other UE115in the group. In some cases, a base station105facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs115without the involvement of a base station105.

Base stations105may communicate with the core network130and with one another. For example, base stations105may interface with the core network130through backhaul links132(e.g., via an S1, N2, N3, or other interface). Base stations105may communicate with one another over backhaul links134(e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations105) or indirectly (e.g., via core network130).

The core network130may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network130may be an evolved packet core (EPC), which may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one Packet Data Network (PDN) gateway (P-GW). The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs115served by base stations105associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC). Each access network entity may communicate with UEs115through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP). In some configurations, various functions of each access network entity or base station105may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station105).

Wireless communications system100may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs115located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system100may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that may be capable of tolerating interference from other users.

Wireless communications system100may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), also known as the millimeter band. In some examples, wireless communications system100may support millimeter wave (mmW) communications between UEs115and base stations105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

In some cases, wireless communications system100may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system100may employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations105and UEs115may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD), time division duplexing (TDD), or a combination of both.

In some examples, base station105or UE115may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system100may use a transmission scheme between a transmitting device (e.g., a base station105) and a receiving device (e.g., a UE115), where the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station105or a UE115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation).

In one example, a base station105may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE115. For instance, some signals (e.g. synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station105multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station105or a receiving device, such as a UE115) a beam direction for subsequent transmission and/or reception by the base station105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station105in a single beam direction (e.g., a direction associated with the receiving device, such as a UE115). In some examples, the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions. For example, a UE115may receive one or more of the signals transmitted by the base station105in different directions, and the UE115may report to the base station105an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by a base station105, a UE115may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE115), or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device).

A receiving device (e.g., a UE115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals from the base station105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions. In some examples a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal). The single receive beam may be aligned in a beam direction determined based at least in part on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least in part on listening according to multiple beam directions).

In some cases, the antennas of a base station105or UE115may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with a base station105may be located in diverse geographic locations. A base station105may have an antenna array with a number of rows and columns of antenna ports that the base station105may use to support beamforming of communications with a UE115. Likewise, a UE115may have one or more antenna arrays that may support various MIMO or beamforming operations.

In some cases, wireless communications system100may be a packet-based network that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE115and a base station105or core network130supporting radio bearers for user plane data. At the Physical layer, transport channels may be mapped to physical channels.

In some cases, UEs115and base stations105may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions). In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of Ts=1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms), where the frame period may be expressed as Tf=307,200 Ts. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period). Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communications system100, and may be referred to as a transmission time interval (TTI). In other cases, a smallest scheduling unit of the wireless communications system100may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs).

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE115and a base station105.

The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link125. For example, a carrier of a communication link125may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)), and may be positioned according to a channel raster for discovery by UEs115. Carriers may be downlink or uplink (e.g., in an FDD mode), or be configured to carry downlink and uplink communications (e.g., in a TDD mode). In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)).

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR). For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc.) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). In some examples, each served UE115may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs115may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type).

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme). Thus, the more resource elements that a UE115receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers), and the use of multiple spatial layers may further increase the data rate for communications with a UE115.

Devices of the wireless communications system100(e.g., base stations105or UEs115) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system100may include base stations105and/or UEs115that support simultaneous communications via carriers associated with more than one different carrier bandwidth.

Wireless communications system100may support communication with a UE115on multiple cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier operation. A UE115may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

In some cases, wireless communications system100may utilize enhanced component carriers (eCCs). An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link). An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum). An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs115that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than other component carriers, which may include use of a reduced symbol duration as compared with symbol durations of the other component carriers. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device, such as a UE115or base station105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc.) at reduced symbol durations (e.g., 16.67 microseconds). A TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.

Wireless communications system100may be an NR system that may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency domain) and horizontal (e.g., across the time domain) sharing of resources.

In some examples, a UE115may receive from a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node, transmit, based on the configuration, a random access message using the random access resources associated with monitoring by the relay node, where the random access message uses a timing advance associated with uplink data transmissions by the UE115, and communicate with the base station via the relay node based on the random access message. The relay node may determine, based on the random access transmission and the timing advance value thereof, whether the UE115can be relayed. An advantage of such techniques may include improved throughput, improved system efficiency, extended coverage, support of low power transmissions, and improved user experience.

A UE115may monitor for a relay reference signal from a relay node, determine a signal strength of the relay reference signal and a timing of the relay reference signal based on the monitoring, and transmit, to a base station, a downlink relay request based on the determining. The UE may determine whether the UE115can be relayed. An advantage of such techniques may include improved throughput, improved system efficiency, extended coverage, support of low power transmissions, and improved user experience.

A UE may receive a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node, receive a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the base station, identify, based on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the base station, or both, and perform a cross-TTI channel estimation based on the identifying. An advantage of such techniques may include improved channel estimation during cross-TTI channel estimation procedures, and improved user experience based thereon.

FIG.2illustrates an example of a wireless communications system200that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, wireless communications system200may implement aspects of wireless communications systems100and200.

In some examples, a base station105-amay serve one or more UEs115. Base station105-amay also perform relay communications with UE115-avia relay node105-b. Relay procedures may provide coverage, enhanced throughput, or both, in some geographic areas. For instance, UE115-amay be too far away from base station105-ato consistently receive downlink signals or send uplink signals, and base station105-amay communicate with UE115-ausing relay procedures via relay node105-b. Or, base station105-aor UE115-amay initiate relay procedures when throughput to UE115-ais deficient.

Network-based relay procedures (e.g., static relay procedures) may be implemented in outband relay procedures or inband relay node procedures. In some examples of outband relay procedures, access links and backhaul links may be on different carrier frequencies. For instance, a backhaul link205between a donor base station105-aand a relay node105-bmay occur on a first frequency carrier (e.g., F1), and an access link210between relay node105-band UE115-amay occur on a second frequency carrier (e.g., F2). In some examples of inband relay node procedures, backhaul links and relay links may be time division multiplexed (TDM). For example, backhaul link205may occur on a first frequency carrier (e.g., F1) and access link210may occur on the same first frequency carrier (e.g., F1). Relay node105-bmay, in an inband relay node, create a separate cell distinct from the cell of the donor base station105-a, which may be referred to as inband non-single frequency network (SFN). Or in an inband relay node, relay node105-bmay be part of the cell of the donor base station105-a, having the same physical cell identifier (PCI) as the donor base station105-a, which may be referred to as inband SFN relay.

Inband SFN relay may be used in various wireless communications systems, including narrowband internet of things (NB-IoT), machine type communications (MTC), evolved MTC (eMTC), or the like. In such examples, the relay procedures may be transparent (e.g., to support legacy UEs115). However, transparent relay procedures may experience some constraints. For instance, for downlink communications, devices in some systems (e.g., NB-IoT, eMTC, etc.) may use cross-subframe channel estimation for demodulation. However, when a relay node105-bor a remote UE115-ainitiate or terminate relay transmissions, channel parameters may change suddenly, and performance of some UEs may be negatively affected based on poor channel estimation. If uplink synchronization is based on a timing of base station105-a, then uplink signals from two UEs115performing uplink relay procedures may not be synchronized upon arrival at the relay node. This may result in uplink performance degradation (e.g., if the timing error for one or both of the UEs115is greater than a cyclic prefix length). Some implementations may mitigate these constraints (e.g., relay procedures may only be enabled for DMRS based transmissions, which may address downlink issues). However, such mitigating implementations may not apply to some systems (e.g., NB-IoT systems, eMTC systems, or the like).

Base station105-aand UE115-amay perform relay communications via relay node105-bin some examples, (e.g., non-transparent inband relay node procedures). To address cross-subframe channel estimation issues that arise when performing relay communications, base station105-amay configure remote UE115-awith a set of valid transmission time intervals (e.g., subframes) for downlink transmissions from the base station, and relay node105-bmay configure the same remote UE115-awith a set of valid TTIs (e.g., subframes) for relay transmissions from relay node105-b. UE115-amay thus determine a first set of TTIs for receiving downlink transmissions, a second set of TTIs for receiving relay transmissions, and a third set of subframes for receiving both (e.g., for receiving downlink transmissions that are multiplexed (e.g., via FDM) with relay transmission). Similarly, TTI allocations may be configured for uplink transmissions. Subframe allocations supporting these techniques are described in greater detail with respect toFIGS.13and16.

In some cases, if uplink synchronization for UE115-ais based on base station105-atiming, then uplink signals from two UEs115using uplink relay procedures may not be synchronized for arrival at relay node105-b. Relay node105-bmay not be able to determine whether remote UE115-bis geographically located close enough to relay node105-bto perform relay communications. In such examples, base station105-amay configure remote UE115-ato transmit a random access transmission with an uplink timing advance value, so that relay node105-bcan identify a transmission timing of remote UE115-aand determine whether remote UE115-acan be relayed, as described in greater detail with respect toFIGS.11and13. In some examples, relay node105-bmay transmit a relay reference signal (e.g., CSI-RS) to remote UE115-afor relay discovery. Remote UE115-amay measure the reference signal receive power (RSRP) of the relay reference signal and may identify an estimated timing for the reference signal. If the estimated timing satisfies a timing threshold (e.g., is less than a cyclic prefix length) and if the RSRP satisfies a power threshold, then UE115-amay report to base station105-athat it is capable of relay procedures with relay node105-b, and may request downlink relaying from base station105-avia relay node105-b, as described in greater detail with respect toFIGS.12and14.

FIG.3illustrates an example of a transmission mode switching scheme300that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, transmission mode switching scheme300may implement aspects of wireless communications systems100and200.

In some examples, a relay node105may perform downlink synchronization during inband SFN relay procedures (e.g., for LTE, MTC, NB-IoT systems, or the like). A base station105may transmit a backhaul subframe305to a relay node, according to base station transmission timing. Backhaul subframe305may include 14 symbols (e.g., symbols0-13). Backhaul subframe305may experience a propagation delay310. A relay node105may receive the backhaul subframe305after the propagation delay310according to the relay node receive timing. The relay node105may set its downlink timing to be equal to the measured downlink timing from the base station105, as measured at the relay node105. In some examples, the relay node105may not transmit a cell-specific reference signal (CRS). Backhaul subframe305may include a control region and CRS in the first symbol (e.g., symbol0). Thus, instead of receiving a control region and CRS during the first symbol of backhaul subframe305, the relay node105may perform transmit/receive switching during the first symbol (e.g., symbol0). For instance, the relay node105may receive a previous backhaul subframe, prior to backhaul subframe305, according to the measured timing of downlink signaling from the base station105(e.g., offset from the base station transmit timing by the propagation delay310). The relay node105may relay the previous backhaul subframe, including symbol13of the previous backhaul subframe. Then, during symbol zero of the backhaul subframe305, during switching window315-a, the relay node105may switch from transmit mode to receive mode. The relay node105may then receive all of the data symbols of backhaul subframe305(e.g., symbols1-13). During the first symbol (e.g., symbol0) of the next subframe (e.g., during switching window315-b), the relay node105may switch from receive mode to transmit mode. Relay node105may then transmit, beginning with the first data symbol of backhaul subframe305(e.g., symbol1) all of the received data symbols of backhaul subframe305according to relay node transmit timing. Because a remote UE115will receive all of the data symbols relayed by relay node105, UE115may remain unaffected by the mode switching performed during the first symbol of backhaul subframe305.

FIG.4illustrates an example of a transmission mode switching scheme400that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, transmission mode switching scheme400may implement aspects of wireless communications systems100and200.

In some examples, a relay node1405and a UE115may perform uplink synchronization during inband SFN relay procedures (e.g., for LTE, MTC, NB-IoT systems, or the like). The relay node105may set its uplink timing to be equal to the uplink timing for a physical uplink shared channel (PUSCH) based on a timing advance offset received from the base station105.

In such examples, a relay node105may switch between transmission mode and receive mode during the last symbol of a transmit subframe or receive subframe. For instance, the relay node105may receive transmissions from remote UE115during subframe1, and during the final symbol405-aof subframe1, the relay node105may switch from receive mode to transmit mode. During subframe2, the relay node105may transmit the data symbols received during subframe1from the remote UE115to the donor base station105. During the final symbol405-bof subframe2, the relay node105may switch from transmit mode to receive mode. During subframe3, the relay node105may receive transmissions from the remote UE115, and during the final symbol405-cof subframe3the relay node105may switch from receive mode to transmit mode. During subframe4, base station105may relay the transmission receive during subframe3from the remote UE115to the donor base station105. During final symbol405-dof subframe4, the relay node105may switch from transmit mode to receive mode.

FIG.5illustrates an example of a transmission mode switching scheme500that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, transmission mode switching scheme500may implement aspects of wireless communications systems100and200.

In some examples, a relay node105and a UE115may perform uplink synchronization during inband SFN relay procedures (e.g., for LTE, MTC, NB-IoT systems, or the like). The relay node105may set its uplink timing to be equal to the uplink timing for a physical uplink shared channel (PUSCH) based on a timing advance offset received from the base station105.

In such examples, a relay node105may switch between transmit mode and receive mode during the first symbol and the last symbol, respectively, of each uplink transmission subframe of relay transmission to the donor base station105. For instance, during subframe1, the relay node105may receive uplink relay transmissions from a remote UE115. During the first symbol505-aof subframe2, the relay node105may switch from receive mode to transmit mode. The relay node105may transmit the uplink relay message received during subframe1to the donor base station105during subframe2. During the final symbol510-aof subframe2, the relay node105may switch from transmit mode back to receive mode to receive uplink relay messages from the remote UE115during subframe3. During the first symbol of subframe4, the relay node105may switch from receive mode to transmit mode and may transmit the received uplink relay messages from subframe3to the donor base station105. During the final symbol510-b, the relay node05may switch back to receive mode.

FIG.6illustrates an example of a transmission mode switching scheme600that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, transmission mode switching scheme600may implement aspects of wireless communications systems100and200.

In some examples, a relay node105and a UE115may perform uplink synchronization during inband SFN relay procedures (e.g., for LTE, MTC, NB-IoT systems, or the like). The relay node105may set its uplink timing to be equal to the uplink timing for a physical uplink shared channel (PUSCH) based on a timing advance offset received from the base station105.

In some examples, the relay node105may perform uplink synchronization according to relay node receive timing1, as described with respect toFIG.4. That is, the relay node105may switch between transmit mode and receive mode during the final symbol of each subframe. Thus, the relay node may receive an uplink relay message from a UE. During symbol13of the uplink message of the previous subframe (e.g., during switching window610-a), the relay node may switch from receive mode to transmit mode. The relay node may then transmit data symbols0-12to the donor base station105during the first thirteen symbols of subframe1. The donor base station105may receive the subframe transmitted during subframe1after propagation delay605. During the final symbol13of subframe1, the relay node may switch from transmit mode to receive mode (e.g., during switching window610-b), and may begging receiving symbol zero of the subsequent uplink relay message from the remote UE115.

In a second example, the relay node105may perform uplink synchronization according to relay node receive timing2, as described with respect toFIG.5. That is, the relay node105That is, the relay node105may switch between transmit mode and receive mode during the first symbol and the final symbol of each uplink subframe for relay transmissions to the donor base station105. Thus, the relay node may receive an uplink relay message from a UE during a subframe prior to subframe1. During the first symbol (symbol0) of subframe1(e.g., during switching window615-a), the relay node may switch from receive mode to transmit mode. The relay node may then transmit data symbols1-12to the donor base station105during the symbols1-12. During the final symbol (symbol13) of subframe1(e.g., during switching window615-b), the relay node may switch from transmit mode to receive mode. The donor base station105may receive the subframe transmitted during subframe1after propagation delay605. For the entirety of a subframe subsequent to subframe1, the relay node105may receive a subsequent uplink relay message from the remote UE115.

FIG.7illustrates an example of a wireless communications system700that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, wireless communications system700may implement aspects of wireless communications system100. In some examples, base station105-bmay communicate with one or more UEs115(e.g., UE115-b, and UE115-c). Base station105-cmay also communicate with relay node105-d, and may perform relay communications with one or more of UE115-band IE115-cvia relay node105-d.

Relay node105-dmay set its uplink receive timing (e.g., the timing at which it expects to receive uplink relay communications from a remote UE115) equal to its uplink transmit timing (e.g., the timing at which relay node105-dsends uplink relay transmissions to base station105-c). However, UE115-band UE115-cmay be timing advanced for uplink synchronization at base station105-cand not at relay node105-d. That is, UE115-bmay be configured with a first timing advance value to offset the propagation delay resulting from being geographically located distance1(d1) from base station105-c. UE115-cmay be configured with a second timing advance value to offset the propagation delay resulting from being geographically located distance3(d3) from base station105-c. Relay node105-dmay be geographically located distance2(d2) from base station105-c.

Although UE115-band UE115-care timing advanced for uplink synchronization with respect to base station105-c, they may not be uplink synchronized with respect to relay node105-d. Thus, because the first timing advance value for UE115-bis smaller than the second timing advance value for UE115-c, an uplink relay transmission705-afrom UE115-bmay arrive at relay node105-dsooner than an uplink relay transmission705-bfrom UE115-c. In some examples, the timing error (e.g., the amount of time by which uplink relay transmission715is off from the uplink receive timing at relay node105-d) may be within a timing error threshold, and a UE115may be relayed (e.g., may be able to participate in relay communications with base station105-cvia relay node105-dbecause the timing error is not so great as to degrade communications). Such scenarios as described in greater detail with respect toFIG.9. However, in some examples, the timing error may not be within a timing error threshold (e.g., may be greater than a cyclic prefix length), and the UE115may not be relayed. Such scenarios are described in greater detail with respect toFIG.8. However, relay node105-bmay be unaware of which UEs115can be relayed and which UEs115cannot be relayed (e.g., because relay node105may be unaware of timing advance values for each UE115, and UEs115may be mobile and their positions and timing advance values may change). Various approaches for determining which UEs115can be relayed are described with respect toFIGS.10-16.

FIG.8illustrates an example of a timing scheme800that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, timing scheme800may implement aspects of wireless communications systems100and700. In some examples, a UE115(e.g.,115-b) may transmit signals that, because of the geographic position of UE115-b, may exceed a timing error threshold, and UE115-cmay not be relayed.

A base station (e.g., base station105-c) may send downlink transmissions835to UE115-b. UE115-bmay receive downlink transmission835after propagation delay805. UE115-bmay send uplink transmission840with a timing advance (T2). That is, UE115-bmay transmit uplink transmission840with timing advance T2at UE transmit timing830prior to base station transmit timing815to offset propagation delay805(so that uplink transmission840arrives at base station105-caligned with base station receive timing which may equal base station transmit timing815). However, because base station105-cand relay node105-dare not located at the same place, (e.g., relay node105-dmay be closer to UE115-bthan base station105-c), relay node105-dmay receive uplink transmission840at measured uplink relay receive timing825based on propagation delay845. That is, UE115-bmay not be timing advanced for uplink synchronization at relay node105-d. UE115-bmay transmit uplink transmission840according to timing advance value T2, which may arrive at relay node105-dat measured uplink relay receive timing825, which may be offset from expected uplink relay receive timing820by T4.

The timing difference T4may be defined as T4=T3−T2+T3. If the starting time of uplink transmission840is later than the relay uplink relay receive timing820(e.g., the timing advance for UE115-bis less than the timing advance value for relay node105-d) then the uplink transmission840from UE115-bmay be out of a receiver FFT window (e.g., T4is greater than the length of a cyclic prefix). In such examples, UE115-bmay not be relayed. However, relay node105-dmay be unaware of whether UE115-bcan be relayed. In some examples, a UE115may be geographically located such that it can be relayed, as described in greater detail with respect toFIG.9.

FIG.9illustrates an example of a timing scheme900that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, timing scheme900may implement aspects of wireless communications systems100and700.

In some examples, a UE115(e.g.,115-c) may transmit signals that, because of the geographic position of UE115-c, may be inside of a timing error threshold, and UE115-ccan be relayed.

A base station (e.g., base station105-c) may send downlink transmissions935to UE115-c. Base station transmit timing915may be different than an expected uplink relay receive timing920by time T1. UE115-cmay receive downlink transmission935after propagation delay905. UE115-cmay send uplink transmission940with a timing advance (T2). That is, UE115-cmay transmit uplink transmission940with timing advance T2at UE transmit timing925prior to base station transmit timing915to offset propagation delay905(so that uplink transmission940arrives at base station105-caligned with base station receive timing which may equal base station transmit timing915). However, because base station105-cand relay node105-dare not located at the same place, (e.g., relay node105-dmay be closer to UE115-cthan base station105-c), relay node105-dmay receive uplink transmission940at measured uplink relay receive timing930, which may be later, based on propagation delay910. That is, UE115-cmay not be timing advanced for uplink synchronization at relay node105-d. UE115-cmay transmit uplink transmission940according to timing advance value T2, which may arrive at relay node105-dat measured uplink relay receive timing930(which may be offset from expected uplink relay receive timing820by T4).

The timing difference T4may be defined as T4=T3−T2+T3. The starting time of uplink transmission940is later than the uplink relay receive timing920. In some cases, the timing advance for UE115-cis greater than the timing advance value for relay node105-d. In such cases, the uplink transmission940from UE115-bmay be within a receiver FFT window (e.g., T4is less than the length of a cyclic prefix). In such examples, UE115-cmay be relayed. However, relay node105-dmay be unaware of whether UE115-ccan be relayed. Techniques for determining whether a remote UE115can be relayed are described with respect toFIGS.10-15

FIG.10illustrates an example of a timing scheme1000that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, timing scheme1000may implement aspects of wireless communications systems100and700.

In some examples, a relay node105-dmay have no information regarding the geographic location of a UE115, and whether the UE115is located close enough to be relayed.

Base station105-cmay transmit a downlink transmission1005according to base station transmit timing1015. A UE115(e.g., UE115-b) may be located closer to base station105-cthan relay node105-d, and may receive downlink transmission1005at UE receive timing930after propagation delay1035, before downlink transmission1005is received at relay node105-d. After propagation delay1040, relay node105-dmay receive downlink transmission1005at relay node receive timing1025. Relay node105-dmay set its timing advance (TARN) based on the relay node receive timing1025.

Base station105-cmay configure relay node105-dto measure an uplink signal (e.g., PRACH transmission1010). UE115-bmay transmit PRACH transmission1010according to UE receive timing1030. The relay node may receive PRACH transmission1010after propagation delay1045, at an estimated or measured timing equal to (Test). Relay node105-dmay attempt to determine the timing difference for UE115-bbased on PRACH1010. However, UE115-bmay transmit PRACH1010with a timing advance value equal to zero (e.g., aligned with UE receive timing1030). In such examples, relay node105-dmay not be able to determine whether UE115-bis close enough based on the timing of PRACH1010. For instance, if Test>TARN, then the relay node may not be able to determine whether UE115-bcan be relayed because the relay node does not know the UE timing advance value for uplink data transmission and cannot estimate the propagation delay between the relay node and the UE115. In some examples, as described in greater detail with respect toFIG.11, UE115-bmay transmit a PRACH message with a timing advance value to allow relay node105-dto determine whether UE115-bcan be relayed.

In some examples, a base station105may send the timing advance value for each served UE115to a relay node105. The relay node105may compare the indicated timing advance values to determine the difference between each timing advance value and the timing advance value for the relay node105. Alternatively, the relay node105may determine the timing advance value for a UE15may reading the random access response message from the base station105to the UE115in downlink signaling. Based on the measured Testfrom the PRACH, the relay node105may estimate the propagation delay between the relay node and the UE115, and determine how closed the UE115is to the relay node105. However, if a UE115is mobile or moving at a high velocity within the cell corresponding to the base station105, then each of these techniques may rely on frequent updates of timing advance values for the mobile UEs115. This may result in decreased efficiency, increased backhaul signaling overhead, system congestion, and decreased user experience. Instead, a UE115may send a PRACH transmission with a timing advance to the relay node105, as described in greater detail with respect toFIG.12, or may receive a relay reference signal from a relay node, as described in greater detail with respect toFIG.13.

FIG.11illustrates an example of a timing scheme1100that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, timing scheme1100may implement aspects of wireless communications systems100and700.

Base station105-cmay transmit a downlink transmission1105according to base station transmit timing1115. A UE115(e.g., UE115-b) may be located closer to base station105-cthan relay node105-d, and may receive downlink transmission1105at UE receive timing930after propagation delay1135, before downlink transmission1105is received at relay node105-d. After propagation delay1140, relay node105-dmay receive downlink transmission1105at relay node receive timing1125. Relay node105-dmay set its timing advance (TARN) based on the relay node receive timing1125.

Base station105-cmay configure relay node105-dto measure an uplink signal (e.g., PRACH transmission1110). A UE115may transmit a PRACH transmission1110with an uplink timing advance value (e.g., using a PUSCH transmission timing). In some examples, base station105may configure a set of PRACH resources for normal uplink synchronization to the base station and another set of dedicated PRACH resources for monitoring by a relay node. A relay node105may monitoring the dedicated relay PRACH resources. The UE115may select the dedicated relay PRACH resources, and may send PRACH transmission1110according to the PUSCH timing advance value on the selected PRACH resources. Thus, one set of PRACH resources may be used for uplink synchronization transmitted without a timing advance, but the dedicated relay PRACH resources may be used to identify, by the relay node105, whether the UE115can be relayed.

In some examples, the base station may explicitly indicate in a control message whether an uplink timing advance is to be applied for a PRACH transmission. For instance, base station105may provide a grant of PRACH resources, and in the grant may indicate that the UE115is to apply a timing advance to the PRACH transmission on the granted PRACH resources. In some examples, the control message may indicate that the timing advance value is to be applied via a 1-bit indicator included in a downlink control information (DCI) message for triggering contention free random access (CFRA) transmissions. The UE115may, based on the 1-bit indicator, apply the non-zero timing advance value to PRACH transmission1110and send PRACH transmission1110over the indicated PRACH resources.

The relay node105-dmay determine, based on the measured timing of PRACH1110, the timing difference of the UE115. In some cases, if the measured timing (e.g., Test) for PRACH1110is less than a threshold (e.g., a cyclic prefix length), then relay node105may determine that the UE115can be relayed. Otherwise, if the measured timing (e.g., Test) is greater than the threshold (e.g., the cyclic prefix length) then the relay node105may determine that the UE115cannot be relayed.

FIG.12illustrates an example of a timing scheme1200that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, timing scheme1200may implement aspects of wireless communications systems100and700.

In some examples, a base station105may send a downlink transmission1205according to base station transmit timing1215. A relay node105may receive downlink transmission1205after propagation delay1235, at UE receive timing1220.

In some examples, the relay node105may transmit a relay transmission1210to a remote UE115. The remote UE115may receive the relay transmission1210after propagation delay1235. The relay node105may identify a measured timing (e.g., Test) for the UE115. The measured timing of the UE115may be the difference between the UE receive timing1220(which may be set equal to a relay node transmit timing) and the UE relay data receive timing1230.

In some examples, the relay transmission1210may be a relay reference signal (e.g., a CSI-RS, or a synchronization signal). The UE115may receive the relay reference signal, and may perform one or more measurements on the relay reference signal. For instance, UE115may determine whether the measured timing is less than a timing threshold (e.g., a cyclic prefix length). The UE115may also determine whether the measured RSRP of the relay reference signal exceeds a power threshold. If the RSRP exceeds the power threshold and the timing less than the timing threshold, then UE115may determine that it can be relayed by the relay node105. In such cases, the UE115may report to the base station105that it can be relayed by the relay node105. In some examples, the UE115may indicate the index corresponding to the relay node105, so that the base station105may initiate relay procedures via the identified relay node105. Thus, based on downlink/uplink symmetry, if the downlink timing from the relay node105to the UE115is synchronized with an acceptable timing error (e.g., the measured timing is less than the threshold), then the uplink timing from the UE115to the relay node105can also be synchronized with an acceptable error.

FIG.13illustrates an example of a subframe allocation1300that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, subframe allocation1300may implement aspects of wireless communications systems100and700.

In some examples, as discussed above, a UE115may perform cross-subframe channel estimation. However, channel conditions may change quickly during relay procedures. That is, when relay transmissions are initiated or terminated during one subframe (e.g., a subframe when a channel estimation measurement is taken) and the channel conditions in subsequent subframes may be quite different than they were when the measurement was taken during the earlier subframe. Thus, cross-subframe channel estimation during relay communications may result in channel degradation. Techniques for addressing cross-subframe channel estimation during relay communications may be applied to relay communication procedures initiated via timing advanced PRACH transmissions (e.g., as described with respect toFIG.11), relay reference signal transmissions (e.g., as described with respect toFIG.12), or both.

To address the cross-subframe channel estimation issues, a UE115may identify different subsets of subframes, and perform cross-subframe channel estimation within the disparate sets of subframes. For example, the UE115may receive a configuration message (e.g., via higher layer signaling) from base station105indicating a set of subframes (e.g., subframe set0including subframe1305, subframe1325, subframe1330, and subframe1350) designated for downlink transmissions from the base station105. The UE115may receive another configuration message from a relay node105indicating a set of subframes (e.g., subframe set1including subframe1310, subframe1315, subframe1335, and subframe1340) designated for downlink relay transmissions from the relay node105. In some examples, the UE115may determine another set of subframes (e.g., subframe set2including subframe1320) for receiving downlink transmissions from base station105and relay transmissions from relay node105. In some cases, a UE115may determine subframe set2based on subframe set0and subframe set1. For instance, a subframe that is included in subframe set1and subframe set0may be identified as a subframe for subframe set2. That is, subframe1320may be included in subframe set0and in subframe set1. Thus, UE115may identify subframe set2based on the overlap between subframe set0and subframe set1. In some cases, UE115may receive an explicit or implicit indication of subframe set2from a base station105or a relay node105. In some cases, some subframes (e.g., subframe1345) may not be included in any subframe set (e.g., subframe set3).

The UE115may monitor for downlink transmissions from the base station105during subframes of subframe set0, may monitor for relay transmissions from the relay node105during subframe set1, and may monitor for both downlink transmissions and relay transmissions during subframe set2. UE115may perform cross-subframe channel estimation separately for each subframe set. UE115may make no channel coherence across subframe sets (e.g., between a subframe from subframe set0and subframe set1). The UE115may also provide CSI reporting respectively for each subframe set, because both channel and interference characteristics may be different for different subframe sets. In some examples, as described below, the CSI report may also include beam management information (e.g., preferred transmit/receive beams). When a UE115receives signals during a subframe of subframe set2, the UE115may receive a downlink transmission that is multiplexed (e.g., frequency division multiplexed (FDM)) with a relay transmission. Such multiplexed signals may support large channel bandwidths and may achieve frequency diversity gains.

In some examples, the UE115may receive one or more reference signals during different subframe sets. For instance, UE115may receive one or more reference signals from the base station during subframe set0, subframe set2, or both. The UE115may receive one or more reference signals from the relay node105during subframe set1, subframe set2, or both. The UE115may determine, based on the received reference signals, one or more transmit beams, receive beams, or both. In some examples, the UE115may include the determined transmit or receive beams or both in a CSI report. The CSI report may include both the cross-subframe channel estimation information described above with respect to each of the independent subframe sets and the beam management information, or the beam management information and channel estimation information may be included in separate CSI reports.

Similarly, a subframe pattern may be established for uplink transmissions. That is, a first set of uplink subframes may be configured for uplink transmissions from the UE115to the donor base station105. A second set of uplink subframes may be configured for transmissions from the relay node105to the base station105. A third set of subframes may be allocated for both uplink transmission from the UE115and uplink relay transmissions from the relay node105(e.g., the uplink transmission from the UE115may be multiplexed with the uplink relay transmission from the relay node105in a subframe of the third set of subframes).

FIG.14illustrates an example of a process flow1400that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, process flow1400may implement aspects of wireless communications systems100,200, and700.

At1405, base station105-emay transmit a configuration message to UE115-d. The configuration message may indicate a set of random access (e.g., PRACH) resources associated with monitoring by a relay node. In some examples, the configuration message may include an indication of a first set of random access resources associated with uplink synchronization and a second set of random access resources that are associated with monitoring by the relay node. In some examples, the configuration information may include a control message (e.g., a DCI message) indicating that the random access message is to be transmitted according to a timing advance value (e.g., according to a PUSCH timing). The control message (e.g., the DCI) may be for triggering contention free random access (CRFA) transmissions, and the DCI may include a one-bit indicator.

At1410, relay node105-fmay monitor for a random access message from UE115-d.

At1415, UE115-dmay transmit a random access message to relay node105-fUE115-dmay transmit the random access message using random access resources associated with monitoring by relay node105-fThe random access message may use a timing advance associated with uplink data transmissions (e.g., PUSCH timing) by UE115-d.

In some examples, upon receiving the random access message, relay node105-fmay measure a timing of the random access message. Relay node105-fmay compare the measured timing of the random access message to a timing (e.g., an error) threshold (e.g., a cyclic prefix length), and may determine that the UE115-dcan be relayed based on the comparing.

At1420, UE115-dmay perform relay communications, and may communicate with base station105-evia relay node105-f.

FIG.15illustrates an example of a process flow1500that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, process flow1500may implement aspects of wireless communications systems100,200, and700.

At1505, UE115-emay monitor for a relay reference signal from relay node105-h.

At1510, relay node105-hmay transmit a relay reference signal. The relay reference signal may be a CSI-RS or a synchronization signal not on the sync raster.

At1515, UE115-emay determine a signal strength of the relay reference signal. For instance, UE115-emay perform one or more measurements on the CSI-RS. UE115-emay determine whether the RSRP of the relay reference signal satisfies a power threshold.

At1520, UE115-emay determine a timing of the relay reference signal. UE115-emay compare the timing of the relay reference signal to a threshold timing value (e.g., a cyclic prefix length), and may determine based on the comparing whether the timing relay reference satisfies the threshold.

At1525, base station105-gmay monitor for a downlink relay request.

At1530, UE115-emay transmit a downlink relay request to base station105-g. Base station105-gmay receive the downlink relay request based on the monitoring at1525. Transmitting the downlink relay request may be based on determining that the timing of the relay reference signal satisfies the threshold at1520(e.g., is less than a cyclic prefix length) and determining that the RSRP of the relay reference signal satisfies a power threshold. The downlink relay request may indicate an index of relay node105-h. Base station105-gmay determine, based on the relay communications, that UE115-ecan be relayed, and may initiate relay communications with the UE115-e.

AT1535, UE115-emay perform relay communications, and may communicate with base station105-gvia relay node105-h.

FIG.16illustrates an example of a process flow1600that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. In some examples, process flow1600may implement aspects of wireless communications systems100,200, and700.

At1605, relay node105-jmay transmit a first configuration message to UE115-fThe first configuration message may indicate a set of TTIs (e.g., a set of subframes) allocated for receiving downlink relay transmissions from relay node105-j.

At1610, base station105-imay transmit a second configuration message to UE115-fThe second configuration message may indicate a second set of TTIs (e.g., subframes) allocated for receiving downlink transmissions from base station105-i.

At1615, UE115-fmay identify a first, second, and third set of TTIs (e.g., subframes, slots, mini-slots, or the like). UE115-fmay identify the first set of TTIs and the second set of TTIs based on the first and second configuration messages, respectfully. In some examples, UE115-fmay identify a third set of TTIs (e.g., subframes) based on the first and second sets of TTIs. For instance, any subframes included in both the first and second configuration messages may be included in the third set of subframes.

In some examples, UE115-fmay identify a first receive beam (e.g., a directional beam on which the first configuration message is transmitted) and a second receive beam (e.g., a directional beam on which the second configuration message is transmitted). In some examples, a beam report may be included in a channel state information report (e.g., at1625and1630, respectively).

UE115-fmay monitor the first set of TTIs for downlink transmissions from relay node105-j. UE115-fmay monitor the second set of TTIs for relay transmissions from relay node105-i. UE115-fmay monitor the third set of TTIs for downlink transmissions from base station105-jmultiplexed (e.g., via FDM) with downlink relay transmissions from relay node105-i.

At1620, UE115-fmay perform cross-TTI channel estimation (e.g., cross-subframe channel estimation). UE115-fmay perform cross-TTI channel estimation for the first set of TTIs, the second set of TTIs, and the third set of TTIs. UE115-fmay refrain from performing any cross-TTI channel estimations across one or more of the sets of TTIs.

At1625, UE115-fmay transmit first channel state information to relay node105-j. First channel state information may apply to the first set of TTIs, the third set of TTIs, or both. In some examples, the first channel state information may also include a beam report indicating one or more preferred beams for subsequent downlink transmissions, uplink transmissions, or both.

At1630, UE115-fmay transmit second channel state information to base station105-i. The second channel state information may apply to the second set of TTIs, the third set of TTIs, or both. In some examples, the second channel state information may also include a beam report indicating one or more preferred beams for subsequent downlink transmissions, uplink transmissions, or both.

In some examples, UE115-fmay transmit uplink transmissions according to an uplink subframe allocation. For instance, a first set of uplink subframes may be allocated for uplink transmissions from UE115-f, a second set of subframes may be allocated for uplink relay transmissions from relay node105-j, and a third set of subframes may be allocated for uplink transmissions multiplexed with uplink relay transmissions. UE115-fmay send uplink transmissions during the first set of subframes, the third set of subframes (e.g., multiplexed with relay transmissions) or both. The relay node105-jmay send uplink relay transmissions during the second set of subframes, the third set of subframes (e.g., multiplexed with uplink transmissions from UE115-f) or both.

FIG.17shows a block diagram1700of a device1705that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The device1705may be an example of aspects of a UE115as described herein. The device1705may include a receiver1710, a communications manager1715, and a transmitter1720. The device1705may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). In some examples, communications manager1715may be implemented by a modem. Communications manager1715may communicate with transmitter1720via a first interface. Communications manager1715may output signals for transmission via the first interface. Communications manager1715may interface with receiver1710via a second interface. Communications manager1715obtain signals via the second interface. In some examples, the modem may implement, via the first interface and the second interface, the techniques and methods described herein. Such techniques may result in power savings for a chipset, improved throughput, improved system efficiency, extended coverage, support of low power transmissions, and improved user experience.

The receiver1710may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to a non-transparent inband relay node in a single frequency network, etc.). Information may be passed on to other components of the device1705. The receiver1710may be an example of aspects of the transceiver2020described with reference toFIG.20. The receiver1710may utilize a single antenna or a set of antennas.

The communications manager1715may receive from a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node, transmit, based on the configuration, a random access message using the random access resources associated with monitoring by the relay node, where the random access message uses a timing advance associated with uplink data transmissions by the UE, and communicate with the base station via the relay node based on the random access message. The communications manager1715may also monitor a relay reference signal from a relay node, determine a signal strength of the relay reference signal and a timing of the relay reference signal based on the monitoring, and transmit, to a base station, a downlink relay request based on the determining. The communications manager1715may also receive a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node, receive a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the base station, identify, based on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the base station, or both, and perform a cross-TTI channel estimation based on the identifying. The communications manager1715may be an example of aspects of the communications manager2010described herein.

The communications manager1715, or its sub-components, may be implemented in hardware, software (e.g., executed by a processor), or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager1715, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager1715, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager1715, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager1715, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter1720may transmit signals generated by other components of the device1705. In some examples, the transmitter1720may be collocated with a receiver1710in a transceiver module. For example, the transmitter1720may be an example of aspects of the transceiver2020described with reference toFIG.20. The transmitter1720may utilize a single antenna or a set of antennas.

FIG.18shows a block diagram1800of a device1805that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The device1805may be an example of aspects of a device1705, or a UE115as described herein. The device1805may include a receiver1810, a communications manager1815, and a transmitter1855. The device1805may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver1810may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to a non-transparent inband relay node in a single frequency network, etc.). Information may be passed on to other components of the device1805. The receiver1810may be an example of aspects of the transceiver2020described with reference toFIG.20. The receiver1810may utilize a single antenna or a set of antennas.

The communications manager1815may be an example of aspects of the communications manager1715as described herein. The communications manager1815may include a configuration message manager1820, a random access message manager1825, a relay communication manager1830, a monitoring manager1835, a relay reference signal manager1840, a downlink relay request manager1845, and a channel state information manager1850. The communications manager1815may be an example of aspects of the communications manager2010described herein.

The configuration message manager1820may receive from a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node.

The random access message manager1825may transmit, based on the configuration, a random access message using the random access resources associated with monitoring by the relay node, where the random access message uses a timing advance associated with uplink data transmissions by the UE.

The relay communication manager1830may communicate with the base station via the relay node based on the random access message.

The monitoring manager1835may monitor a relay reference signal from a relay node.

The relay reference signal manager1840may determine a signal strength of the relay reference signal and a timing of the relay reference signal based on the monitoring.

The downlink relay request manager1845may transmit, to a base station, a downlink relay request based on the determining.

The configuration message manager1820may receive a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node and receive a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the base station.

The relay communication manager1830may identify, based on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the base station, or both.

The channel state information manager1850may perform a cross-TTI channel estimation based on the identifying.

The transmitter1855may transmit signals generated by other components of the device1805. In some examples, the transmitter1855may be collocated with a receiver1810in a transceiver module. For example, the transmitter1855may be an example of aspects of the transceiver2020described with reference toFIG.20. The transmitter1855may utilize a single antenna or a set of antennas.

FIG.19shows a block diagram1900of a communications manager1905that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The communications manager1905may be an example of aspects of a communications manager1715, a communications manager1815, or a communications manager2010described herein. The communications manager1905may include a configuration message manager1910, a random access message manager1915, a relay communication manager1920, a timing manager1925, a monitoring manager1930, a relay reference signal manager1935, a downlink relay request manager1940, a measurement manager1945, a channel state information manager1950, and a beam manager1955. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). In some examples, communications manager1915may be implemented by a modem. Communications manager1915may communicate with transmitter1920via a first interface. Communications manager1915may output signals for transmission via the first interface. Communications manager1915may interface with receiver1910via a second interface. Communications manager1115may obtain signals (e.g., transmitted from a UE115) via the second interface. In some examples, the modem may implement, via the first interface and the second interface, the techniques and methods described herein. Such techniques may result in power savings for a chipset, improved throughput, improved system efficiency, extended coverage, support of low power transmissions, and improved user experience.

The configuration message manager1910may receive from a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node. In some examples, the configuration message manager1910may receive a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node. In some examples, the configuration message manager1910may receive a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the base station. In some examples, the configuration message manager1910may receive, from a relay node, a third configuration message indicating a fourth set of TTIs allocated for transmitting uplink transmissions to the base station. In some cases, the configuration message includes an indication of a first set of random access resources associated with uplink synchronization and a second set of random access resources including the set of random access resources associated with the monitoring by the relay node. In some cases, the configuration message includes a control message indicating that the random access message is to be transmitted according to a timing advance value. In some cases, the control message includes downlink control information for triggering CFRA transmission, the downlink control information including a one-bit indicator.

The random access message manager1915may transmit, based on the configuration, a random access message using the random access resources associated with monitoring by the relay node, where the random access message uses a timing advance associated with uplink data transmissions by the UE.

The relay communication manager1920may communicate with the base station via the relay node based on the random access message. In some examples, the relay communication manager1920may identify, based on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the base station, or both. In some examples, the relay communication manager1920may determine, based on the comparing, whether the timing of the relay reference signal satisfies the threshold timing value, where transmitting the downlink relay request is based on determining that the timing of the relay reference signal satisfies the threshold timing value.

In some examples, the relay communication manager1920may receive, based on the monitoring, downlink relay transmissions from the relay node during the first set of TTIs, the third set of TTIs, or both, or downlink transmissions from the base station during the second set of TTIs, the third set of TTIs, or both, or a combination thereof. In some examples, the relay communication manager1920may receive, during the third set of TTIs, a downlink transmission from the base station and a downlink relay transmission from the relay node, where the downlink transmission and the downlink relay transmission are frequency division multiplexed.

In some examples, the relay communication manager1920may transmit one or more uplink transmissions during the fourth set of TTIs. In some examples, the relay communication manager1920may frequency division multiplexing an uplink transmission from the UE with a relay uplink transmission from the relay node during one or more TTIs of the fourth set of TTIs, where the one or more TTIs of the fourth set of TTIs are also allocated for relay transmissions from the relay node to the base station.

The monitoring manager1930may monitor a relay reference signal from a relay node. In some examples, the monitoring manager1930may monitor one or more of the first set of TTIs, the second set of TTIs, and the third set of TTIs, based on the identifying.

The relay reference signal manager1935may determine a signal strength of the relay reference signal and a timing of the relay reference signal based on the monitoring. In some examples, the relay reference signal manager1935may receive, based on the monitoring, the relay reference signal from the relay node. In some cases, the relay reference signal is a channel state information reference signal (CSI-RS). In some cases, the relay reference signal is a synchronization signal block (SSB) not on the sync raster.

The downlink relay request manager1940may transmit, to a base station, a downlink relay request based on the determining. In some cases, the downlink relay request includes an indication of the relay node.

The channel state information manager1950may perform a cross-TTI channel estimation based on the identifying. In some examples, the channel state information manager1950may perform a first cross-TTI channel estimation for the first set of TTIs, a second cross-TTI channel estimation for the second TTIs, a third cross-TTI channel estimation for the third set of TTIs, or a combination thereof.

In some examples, the channel state information manager1950may report, to the relay node, first channel state information corresponding to the first set of TTIs, the third set of TTIs, or both. In some examples, the channel state information manager1950may report, to the base station, second channel state information corresponding to the second set of TTIs, the third set of TTIs, or both.

The timing manager1925may determine an uplink timing advance value based on a transmission timing of a PUSCH. In some examples, the timing manager1925may apply the uplink timing advance value to the random access message, where transmitting the random access message is according to the uplink timing advance value. In some examples, the timing manager1925may compare the timing of the relay reference signal to a threshold timing value. In some cases, the threshold timing value is based on a cyclic prefix duration.

The measurement manager1945may perform one or more measurements on the relay reference signal. In some examples, the measurement manager1945may determine, based on the one or more measurements, whether a reference signal receive power (RSRP) of the relay reference signal satisfies a power threshold, where transmitting the downlink relay request is based on determining that the RSRP of the reference signal satisfies the power threshold.

The beam manager1955may identify a first receive beam, where receiving the first configuration message includes receiving the first configuration message via the first receive beam. In some examples, identifying a second receive beam, where receiving the second configuration message includes receiving the second configuration message via the second receive beam. In some examples, the beam manager1955may incorporate the beam report in the first channel state information, the second channel state information, or both.

FIG.20shows a diagram of a system2000including a device2005that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The device2005may be an example of or include the components of device1705, device1805, or a UE115as described herein. The device2005may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager2010, an I/O controller2015, a transceiver2020, an antenna2025, memory2030, and a processor2040. These components may be in electronic communication via one or more buses (e.g., bus2045).

The communications manager2010may receive from a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node, transmit, based on the configuration, a random access message using the random access resources associated with monitoring by the relay node, where the random access message uses a timing advance associated with uplink data transmissions by the UE, and communicate with the base station via the relay node based on the random access message. The communications manager2010may also monitor a relay reference signal from a relay node, determine a signal strength of the relay reference signal and a timing of the relay reference signal based on the monitoring, and transmit, to a base station, a downlink relay request based on the determining. The communications manager2010may also receive a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node, receive a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the base station, identify, based on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the base station, or both, and perform a cross-TTI channel estimation based on the identifying.

The I/O controller2015may manage input and output signals for the device2005. The I/O controller2015may also manage peripherals not integrated into the device2005. In some cases, the I/O controller2015may represent a physical connection or port to an external peripheral. In some cases, the I/O controller2015may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®), UNIX®, LINUX®, or another known operating system. In other cases, the I/O controller2015may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller2015may be implemented as part of a processor. In some cases, a user may interact with the device2005via the I/O controller2015or via hardware components controlled by the I/O controller2015.

The transceiver2020may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver2020may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver2020may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna2025. However, in some cases the device may have more than one antenna2025, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory2030may include RAM and ROM. The memory2030may store computer-readable, computer-executable code2035including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory2030may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor2040may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor2040may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor2040. The processor2040may be configured to execute computer-readable instructions stored in a memory (e.g., the memory2030) to cause the device2005to perform various functions (e.g., functions or tasks supporting a non-transparent inband relay node in a single frequency network).

The code2035may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code2035may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code2035may not be directly executable by the processor2040but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG.21shows a block diagram2100of a device2105that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The device2105may be an example of aspects of a base station105as described herein. The device2105may include a receiver2110, a communications manager2115, and a transmitter2120. The device2105may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver2110may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to a non-transparent inband relay node in a single frequency network, etc.). Information may be passed on to other components of the device2105. The receiver2110may be an example of aspects of the transceiver2420described with reference toFIG.24. The receiver2110may utilize a single antenna or a set of antennas.

The communications manager2115may transmit, to a UE, a configuration message indicating a set of random access resources associated with monitoring by a relay node, monitor for an uplink relay request from a relay node, receive, based on the monitoring, the uplink relay request includes an indication of a UE, and communicate with the UE via the relay node based on the uplink relay request. The communications manager2115may also monitor a set of one or more random access resources for a random access message from a UE, receive, based on the monitoring, a random access message over the set of random access resources, where the random access message uses a timing advance associated with uplink data transmissions by the UE, and perform relay operations to facilitate communication between the UE and the base station based on receiving the random access message. The communications manager2115may also monitor for a downlink relay request from a UE, receive, based on the monitoring, the downlink relay request includes an indication of a relay node, communicate, based on the downlink relay request, with the UE via the relay node, transmit, to a UE a relay reference signal, monitor for downlink signaling from a base station initiating relay communications with the UE based on the relay reference signal, and perform relay operations to facilitate communication between the UE and the base station based on the downlink signaling. The communications manager2115may also perform relay communications with a UE, via a relay node and transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink transmissions from the base station to the UE, where a second set of TTIs is allocated for downlink relay transmissions from the relay node to the UE, and where a third set of TTIs is allocated for downlink transmissions from the base station to the UE, from the relay node to the UE, or both. The communications manager2115may also perform relay operations to facilitate communication between a UE and a base station and transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink relay transmissions from the relay node to the UE, where a second set of TTIs is allocated for downlink transmissions from the base station to the UE, and where a third set of TTIs including a subset of the first set of TTIs is allocated for downlink transmissions from the base station to the UE, downlink relay transmissions from the relay node to the UE, or both. The communications manager2115may be an example of aspects of the communications manager2410described herein.

The communications manager2115, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager2115, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager2115, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager2115, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager2115, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter2120may transmit signals generated by other components of the device2105. In some examples, the transmitter2120may be collocated with a receiver2110in a transceiver module. For example, the transmitter2120may be an example of aspects of the transceiver2420described with reference toFIG.24. The transmitter2120may utilize a single antenna or a set of antennas.

FIG.22shows a block diagram2200of a device2205that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The device2205may be an example of aspects of a device2105, or a base station105as described herein. The device2205may include a receiver2210, a communications manager2215, and a transmitter2255. The device2205may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). Each of these components may be in communication with one another (e.g., via one or more buses). In some examples, communications manager2215may be implemented by a modem. Communications manager2215may communicate with transmitter2220via a first interface. Communications manager2215may output signals for transmission via the first interface. Communications manager2215may interface with receiver2210via a second interface. Communications manager2215may obtain signals (e.g., transmitted from a UE115) via the second interface. In some examples, the modem may implement, via the first interface and the second interface, the techniques and methods described herein. Such techniques may result in power savings for a chipset, improved throughput, improved system efficiency, extended coverage, support of low power transmissions, and improved user experience.

The receiver2210may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to a non-transparent inband relay node in a single frequency network, etc.). Information may be passed on to other components of the device2205. The receiver2210may be an example of aspects of the transceiver2420described with reference toFIG.24. The receiver2210may utilize a single antenna or a set of antennas.

The communications manager2215may be an example of aspects of the communications manager2115as described herein. The communications manager2215may include a configuration message manager2220, a monitoring manager2225, an uplink relay request2230, a relay communication manager2235, a random access message manager2240, a downlink relay request manager2245, and a relay reference signal manager2250. The communications manager2215may be an example of aspects of the communications manager2410described herein.

The configuration message manager2220may transmit, to a UE, a configuration message indicating a set of random access resources associated with monitoring by a relay node.

The monitoring manager2225may monitor for an uplink relay request from a relay node.

The uplink relay request2230may receive, based on the monitoring, the uplink relay request includes an indication of a UE.

The relay communication manager2235may communicate with the UE via the relay node based on the uplink relay request.

The monitoring manager2225may monitor a set of one or more random access resources for a random access message from a UE.

The random access message manager2240may receive, based on the monitoring, a random access message over the set of random access resources, where the random access message uses a timing advance associated with uplink data transmissions by the UE.

The relay communication manager2235may perform relay operations to facilitate communication between the UE and the base station based on receiving the random access message.

The downlink relay request manager2245may monitor for a downlink relay request from a UE and receive, based on the monitoring, the downlink relay request includes an indication of a relay node.

The relay communication manager2235may communicate, based on the downlink relay request, with the UE via the relay node.

The relay reference signal manager2250may transmit, to a UE a relay reference signal.

The relay communication manager2235may monitor for downlink signaling from a base station initiating relay communications with the UE based on the relay reference signal and perform relay operations to facilitate communication between the UE and the base station based on the downlink signaling.

The relay communication manager2235may perform relay communications with a UE, via a relay node.

The configuration message manager2220may transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink transmissions from the base station to the UE, where a second set of TTIs is allocated for downlink relay transmissions from the relay node to the UE, and where a third set of TTIs is allocated for downlink transmissions from the base station to the UE, from the relay node to the UE, or both.

The relay communication manager2235may perform relay operations to facilitate communication between a UE and a base station.

The configuration message manager2220may transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink relay transmissions from the relay node to the UE, where a second set of TTIs is allocated for downlink transmissions from the base station to the UE, and where a third set of TTIs including a subset of the first set of TTIs is allocated for downlink transmissions from the base station to the UE, downlink relay transmissions from the relay node to the UE, or both.

The transmitter2255may transmit signals generated by other components of the device2205. In some examples, the transmitter2255may be collocated with a receiver2210in a transceiver module. For example, the transmitter2255may be an example of aspects of the transceiver2420described with reference toFIG.24. The transmitter2255may utilize a single antenna or a set of antennas.

FIG.23shows a block diagram2300of a communications manager2305that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The communications manager2305may be an example of aspects of a communications manager2115, a communications manager2215, or a communications manager2410described herein. The communications manager2305may include a configuration message manager2310, a monitoring manager2315, an uplink relay request2320, a relay communication manager2325, a random access message manager2330, a timing manager2335, a downlink relay request manager2340, a relay reference signal manager2345, and a channel state information manager2350. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The configuration message manager2310may transmit, to a UE, a configuration message indicating a set of random access resources associated with monitoring by a relay node. In some examples, the configuration message manager2310may transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink transmissions from the base station to the UE, where a second set of TTIs is allocated for downlink relay transmissions from the relay node to the UE, and where a third set of TTIs is allocated for downlink transmissions from the base station to the UE, from the relay node to the UE, or both. In some examples, the configuration message manager2310may transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink relay transmissions from the relay node to the UE, where a second set of TTIs is allocated for downlink transmissions from the base station to the UE, and where a third set of TTIs including a subset of the first set of TTIs is allocated for downlink transmissions from the base station to the UE, downlink relay transmissions from the relay node to the UE, or both. In some examples, the configuration message manager2310may transmit, to the UE, a second configuration message indicating a fourth set of TTIs allocated for transmitting uplink transmissions from the UE to the base station.

In some examples, the configuration message manager2310may receive, from the base station, a second configuration message indicating a fourth set of TTIs allocated for transmitting uplink relay transmissions from the relay node to the base station. In some cases, the configuration message includes an indication of a first set of random access resources associated with uplink synchronization and a second set of random access resources including the set of random access resources associated with the monitoring by the relay node. In some cases, the configuration message includes a control message indicating that the random access message is to be transmitted according to a timing advance value. In some cases, the control message includes a one-bit indicator included in downlink control information for triggering CFRA transmission.

The monitoring manager2315may monitor for an uplink relay request from a relay node. In some examples, the monitoring manager2315may monitor a set of one or more random access resources for a random access message from a UE.

The uplink relay request2320may receive, based on the monitoring, the uplink relay request includes an indication of a UE.

The relay communication manager2325may communicate with the UE via the relay node based on the uplink relay request.

In some examples, the relay communication manager2325may perform relay operations to facilitate communication between the UE and the base station based on receiving the random access message. In some examples, the relay communication manager2325may communicate, based on the downlink relay request, with the UE via the relay node. In some examples, the relay communication manager2325may monitor for downlink signaling from a base station initiating relay communications with the UE based on the relay reference signal. In some examples, the relay communication manager2325may perform relay operations to facilitate communication between the UE and the base station based on the downlink signaling.

In some examples, the relay communication manager2325may perform relay communications with a UE, via a relay node. In some examples, the relay communication manager2325may perform relay operations to facilitate communication between a UE and a base station. In some examples, the relay communication manager2325may determine, based on comparing, whether the UE can be relayed by the relay node. In some examples, the relay communication manager2325may send one or more downlink transmissions to the UE during the first set of TTIs, the third set of TTIs, or both.

In some examples, the relay communication manager2325may receive uplink transmissions from the UE during the fourth set of TTIs. In some examples, the relay communication manager2325may receive an uplink transmission from the UE during one or more TTIs of the fourth set of TTIs, where the uplink transmission is frequency division multiplexed with a relay uplink transmission from the relay node to the base station. In some examples, the relay communication manager2325may send one or more downlink relay transmissions to the UE during the first set of TTIs, the third set of TTIs, or both. In some examples, the relay communication manager2325may transmit uplink relay transmissions to the base station during the fourth set of TTIs. In some examples, the relay communication manager2325may transmit an uplink relay transmission from the relay node to the base station during one or more TTIs of the fourth set of TTIs, where the uplink relay transmission is frequency division multiplexed with an uplink transmission from the UE to the base station.

The random access message manager2330may receive, based on the monitoring, a random access message over the set of random access resources, where the random access message uses a timing advance associated with uplink data transmissions by the UE.

The downlink relay request manager2340may monitor for a downlink relay request from a UE.

In some examples, receiving, based on the monitoring, the downlink relay request includes an indication of a relay node.

The relay reference signal manager2345may transmit, to a UE a relay reference signal.

In some cases, the relay reference signal is a channel state information reference signal (CSI-RS).

The timing manager2335may measure a timing of the random access message. In some examples, the timing manager2335may compare the measured timing of the random access message to a timing threshold.

The channel state information manager2350may receive, from the UE, a channel state information report corresponding to the first set of TTIs, the third set of TTIs, or both. In some examples, the channel state information manager2350may receive, from the UE, a channel state information report corresponding to the first set of TTIs, the third set of TTIs, or both.

FIG.24shows a diagram of a system2400including a device2405that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The device2405may be an example of or include the components of device2105, device2205, or a base station105as described herein. The device2405may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager2410, a network communications manager2415, a transceiver2420, an antenna2425, memory2430, a processor2440, and an inter-station communications manager2445. These components may be in electronic communication via one or more buses (e.g., bus2450).

The communications manager2410may transmit, to a UE, a configuration message indicating a set of random access resources associated with monitoring by a relay node, monitor for an uplink relay request from a relay node, receive, based on the monitoring, the uplink relay request includes an indication of a UE, and communicate with the UE via the relay node based on the uplink relay request. The communications manager2410may also monitor a set of one or more random access resources for a random access message from a UE, receive, based on the monitoring, a random access message over the set of random access resources, where the random access message uses a timing advance associated with uplink data transmissions by the UE, and perform relay operations to facilitate communication between the UE and the base station based on receiving the random access message. The communications manager2410may also monitor for a downlink relay request from a UE, receive, based on the monitoring, the downlink relay request includes an indication of a relay node, communicate, based on the downlink relay request, with the UE via the relay node, transmit, to a UE a relay reference signal, monitor for downlink signaling from a base station initiating relay communications with the UE based on the relay reference signal, and perform relay operations to facilitate communication between the UE and the base station based on the downlink signaling. The communications manager2410may also perform relay communications with a UE, via a relay node and transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink transmissions from the base station to the UE, where a second set of TTIs is allocated for downlink relay transmissions from the relay node to the UE, and where a third set of TTIs is allocated for downlink transmissions from the base station to the UE, from the relay node to the UE, or both. The communications manager2410may also perform relay operations to facilitate communication between a UE and a base station and transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink relay transmissions from the relay node to the UE, where a second set of TTIs is allocated for downlink transmissions from the base station to the UE, and where a third set of TTIs including a subset of the first set of TTIs is allocated for downlink transmissions from the base station to the UE, downlink relay transmissions from the relay node to the UE, or both.

The network communications manager2415may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager2415may manage the transfer of data communications for client devices, such as one or more UEs115.

The transceiver2420may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver2420may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver2420may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna2425. However, in some cases the device may have more than one antenna2425, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory2430may include RAM, ROM, or a combination thereof. The memory2430may store computer-readable code2435including instructions that, when executed by a processor (e.g., the processor2440) cause the device to perform various functions described herein. In some cases, the memory2430may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor2440may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor2440may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor2440. The processor2440may be configured to execute computer-readable instructions stored in a memory (e.g., the memory2430) to cause the device2405to perform various functions (e.g., functions or tasks supporting a non-transparent inband relay node in a single frequency network).

The inter-station communications manager2445may manage communications with other base station105, and may include a controller or scheduler for controlling communications with UEs115in cooperation with other base stations105. For example, the inter-station communications manager2445may coordinate scheduling for transmissions to UEs115for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager2445may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations105.

The code2435may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code2435may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code2435may not be directly executable by the processor2440but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG.25shows a flowchart illustrating a method2500that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method2500may be implemented by a UE115or its components as described herein. For example, the operations of method2500may be performed by a communications manager as described with reference toFIGS.17through20. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally, or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At2505, the UE may receive from a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node. The operations of2505may be performed according to the methods described herein. In some examples, aspects of the operations of2505may be performed by a configuration message manager as described with reference toFIGS.17through20.

At2510, the UE may transmit, based on the configuration, a random access message using the random access resources associated with monitoring by the relay node, where the random access message uses a timing advance associated with uplink data transmissions by the UE. The operations of2510may be performed according to the methods described herein. In some examples, aspects of the operations of2510may be performed by a random access message manager as described with reference toFIGS.17through20.

At2515, the UE may communicate with the base station via the relay node based on the random access message. The operations of2515may be performed according to the methods described herein. In some examples, aspects of the operations of2515may be performed by a relay communication manager as described with reference toFIGS.17through20.

FIG.26shows a flowchart illustrating a method2600that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method2600may be implemented by a base station105or its components as described herein. For example, the operations of method2600may be performed by a communications manager as described with reference toFIGS.21through24. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally, or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At2605, the base station may transmit, to a UE, a configuration message indicating a set of random access resources associated with monitoring by a relay node. The operations of2605may be performed according to the methods described herein. In some examples, aspects of the operations of2605may be performed by a configuration message manager as described with reference toFIGS.21through24.

At2610, the base station may monitor for an uplink relay request from a relay node. The operations of2610may be performed according to the methods described herein. In some examples, aspects of the operations of2610may be performed by a monitoring manager as described with reference toFIGS.21through24.

At2615, the base station may receive, based on the monitoring, the uplink relay request includes an indication of a UE. The operations of2615may be performed according to the methods described herein. In some examples, aspects of the operations of2615may be performed by an uplink relay request as described with reference toFIGS.21through24.

At2620, the base station may communicate with the UE via the relay node based on the uplink relay request. The operations of2620may be performed according to the methods described herein. In some examples, aspects of the operations of2620may be performed by a relay communication manager as described with reference toFIGS.21through24.

FIG.27shows a flowchart illustrating a method2700that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method2700may be implemented by a base station105or its components as described herein. For example, the operations of method2700may be performed by a communications manager as described with reference toFIGS.21through24. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally, or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At2705, the base station may monitor a set of one or more random access resources for a random access message from a UE. The operations of2705may be performed according to the methods described herein. In some examples, aspects of the operations of2705may be performed by a monitoring manager as described with reference toFIGS.21through24.

At2710, the base station may receive, based on the monitoring, a random access message over the set of random access resources, where the random access message uses a timing advance associated with uplink data transmissions by the UE. The operations of2710may be performed according to the methods described herein. In some examples, aspects of the operations of2710may be performed by a random access message manager as described with reference toFIGS.21through24.

At2715, the base station may perform relay operations to facilitate communication between the UE and the base station based on receiving the random access message. The operations of2715may be performed according to the methods described herein. In some examples, aspects of the operations of2715may be performed by a relay communication manager as described with reference toFIGS.21through24.

FIG.28shows a flowchart illustrating a method2800that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method2800may be implemented by a UE115or its components as described herein. For example, the operations of method2800may be performed by a communications manager as described with reference toFIGS.17through20. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally, or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At2805, the UE may monitor a relay reference signal from a relay node. The operations of2805may be performed according to the methods described herein. In some examples, aspects of the operations of2805may be performed by a monitoring manager as described with reference toFIGS.17through20.

At2810, the UE may determine a signal strength of the relay reference signal and a timing of the relay reference signal based on the monitoring. The operations of2810may be performed according to the methods described herein. In some examples, aspects of the operations of2810may be performed by a relay reference signal manager as described with reference toFIGS.17through20.

At2815, the UE may transmit, to a base station, a downlink relay request based on the determining. The operations of2815may be performed according to the methods described herein. In some examples, aspects of the operations of2815may be performed by a downlink relay request manager as described with reference toFIGS.17through20.

FIG.29shows a flowchart illustrating a method2900that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method2900may be implemented by a base station105or its components as described herein. For example, the operations of method2900may be performed by a communications manager as described with reference toFIGS.21through24. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally, or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At2905, the base station may monitor for a downlink relay request from a UE. The operations of2905may be performed according to the methods described herein. In some examples, aspects of the operations of2905may be performed by a downlink relay request manager as described with reference toFIGS.21through24.

At2910, the base station may receive, based on the monitoring, the downlink relay request includes an indication of a relay node. The operations of2910may be performed according to the methods described herein. In some examples, aspects of the operations of2910may be performed by a downlink relay request manager as described with reference toFIGS.21through24.

At2915, the base station may communicate, based on the downlink relay request, with the UE via the relay node. The operations of2915may be performed according to the methods described herein. In some examples, aspects of the operations of2915may be performed by a relay communication manager as described with reference toFIGS.21through24.

FIG.30shows a flowchart illustrating a method3000that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method3000may be implemented by a base station105or its components as described herein. For example, the operations of method3000may be performed by a communications manager as described with reference toFIGS.21through24. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally, or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At3005, the base station may transmit, to a UE a relay reference signal. The operations of3005may be performed according to the methods described herein. In some examples, aspects of the operations of3005may be performed by a relay reference signal manager as described with reference toFIGS.21through24.

At3010, the base station may monitor for downlink signaling from a base station initiating relay communications with the UE based on the relay reference signal. The operations of3010may be performed according to the methods described herein. In some examples, aspects of the operations of3010may be performed by a relay communication manager as described with reference toFIGS.21through24.

At3015, the base station may perform relay operations to facilitate communication between the UE and the base station based on the downlink signaling. The operations of3015may be performed according to the methods described herein. In some examples, aspects of the operations of3015may be performed by a relay communication manager as described with reference toFIGS.21through24.

FIG.31shows a flowchart illustrating a method3100that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method3100may be implemented by a UE115or its components as described herein. For example, the operations of method3100may be performed by a communications manager as described with reference toFIGS.17through20. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally, or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At3105, the UE may receive a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node. The operations of3105may be performed according to the methods described herein. In some examples, aspects of the operations of3105may be performed by a configuration message manager as described with reference toFIGS.17through20.

At3110, the UE may receive a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the base station. The operations of3110may be performed according to the methods described herein. In some examples, aspects of the operations of3110may be performed by a configuration message manager as described with reference toFIGS.17through20.

At3115, the UE may identify, based on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the base station, or both. The operations of3115may be performed according to the methods described herein. In some examples, aspects of the operations of3115may be performed by a relay communication manager as described with reference toFIGS.17through20.

At3120, the UE may perform a cross-TTI channel estimation based on the identifying. The operations of3120may be performed according to the methods described herein. In some examples, aspects of the operations of3120may be performed by a channel state information manager as described with reference toFIGS.17through20.

FIG.32shows a flowchart illustrating a method3200that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method3200may be implemented by a base station105or its components as described herein. For example, the operations of method3200may be performed by a communications manager as described with reference toFIGS.21through24. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally, or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At3205, the base station may perform relay communications with a UE, via a relay node. The operations of3205may be performed according to the methods described herein. In some examples, aspects of the operations of3205may be performed by a relay communication manager as described with reference toFIGS.21through24.

At3210, the base station may transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink transmissions from the base station to the UE, where a second set of TTIs is allocated for downlink relay transmissions from the relay node to the UE, and where a third set of TTIs is allocated for downlink transmissions from the base station to the UE, from the relay node to the UE, or both. The operations of3210may be performed according to the methods described herein. In some examples, aspects of the operations of3210may be performed by a configuration message manager as described with reference toFIGS.21through24.

FIG.33shows a flowchart illustrating a method3300that supports a non-transparent inband relay node in a single frequency network in accordance with aspects of the present disclosure. The operations of method3300may be implemented by a base station105or its components as described herein. For example, the operations of method3300may be performed by a communications manager as described with reference toFIGS.21through24. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally, or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At3305, the base station may perform relay operations to facilitate communication between a UE and a base station. The operations of3305may be performed according to the methods described herein. In some examples, aspects of the operations of3305may be performed by a relay communication manager as described with reference toFIGS.21through24.

At3310, the base station may transmit, to the UE, a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for downlink relay transmissions from the relay node to the UE, where a second set of TTIs is allocated for downlink transmissions from the base station to the UE, and where a third set of TTIs including a subset of the first set of TTIs is allocated for downlink transmissions from the base station to the UE, downlink relay transmissions from the relay node to the UE, or both. The operations of3310may be performed according to the methods described herein. In some examples, aspects of the operations of3310may be performed by a configuration message manager as described with reference toFIGS.21through24.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and other systems. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM).

An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GPP). CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell may be associated with a lower-powered base station, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). A base station for a macro cell may be referred to as a macro base station. A base station for a small cell may be referred to as a small cell base station, a pico base station, a femto base station, or a home base station. A base station may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.

The wireless communications systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.