Adaptive sounding reference signal mapping for improving channel estimation

Abstract

Aspects of an adaptive sounding reference signal mapping implemented by a user equipment (UE) to improve channel estimation are described in this disclosure. In aspects, a set of sounding reference signal (SRS) symbols including at least a first and a second SRS symbol is generated. An offset of the second SRS symbol is determined based on a difference between a first radio chain and a second radio chain of the UE. Then, the first and second SRS symbols are mapped to an antenna port of the first radio chain. The UE transmits the first SRS symbol to a base station via the antenna port of the first radio chain, and transmits the second SRS symbol to the base station via the antenna port of the first radio chain when the offset is applied to the first radio chain. By doing so, the UE can improve channel estimation for uplink and / or downlink communication.

Description

Background Art

[0001] Many electronic devices enable users to communicate with other devices and access resources via a wireless network. The wireless network is typically provided and managed by a base station of the wireless network. To communicate over the wireless network, a mobile station establishes a connection with one of the base stations to receive downlink or transmit uplink information (e.g., control signaling or data). At the physical layer, this information is communicated as corresponding signals transmitted by the mobile station or the base station over the channels of the wireless communication environment.

[0002] To implement the corresponding transmitter configuration, a mobile station typically uses a sounding channel over which it transmits reference signals to the base station, and the base station estimates the channel characteristics between the base station and the mobile station for wireless communication. To this end, the mobile station transmits reference signals via a transmit chain connected to a corresponding antenna of the mobile station. However, due to the cost and complexity associated with switching the transmit chain of the mobile station between antennas, most mobile stations are capable of transmitting reference signals via one or two corresponding antennas. Thus, the transmit chain switching configuration of the mobile station may limit the number of reference signals that the mobile station can transmit (e.g., two reference signals), which in turn may limit the accuracy with which the base station can estimate the wireless communication channel. Summary of the Invention

[0003] The present disclosure describes devices and techniques for adaptive sounding reference signal mapping for improving channel estimation. In various aspects, a user equipment (UE) generates a set of sounding reference signal (SRS) symbols, the set of SRS symbols including at least first and second SRS symbols (e.g., two SRS symbols in a sequence of four SRS symbols). An offset for the second SRS symbol is determined based on a difference between a first radio chain and a second radio chain of the UE. The first SRS symbol and the second SRS symbol (e.g., the offset SRS symbol) are then mapped to an antenna port (e.g., a physical antenna port) of the first radio chain of the UE. The UE transmits the first SRS symbol to the base station via the antenna port of the first radio chain of the UE, and transmits the second SRS symbol to the base station via the antenna port of the first radio chain while applying the offset to the first radio chain. Based on the channel information determined from at least two SRS symbols, the UE communicates uplink or downlink signaling or information with the base station. By doing so, the UE can improve channel estimation for uplink and / or downlink communication, which in turn can achieve increased communication throughput between the UE and the base station.

[0004] In some aspects, a method for adaptive sounding reference signal mapping performed by a user equipment (UE) includes generating a set of sounding reference signal (SRS) symbols, the set of SRS symbols including at least a first SRS symbol and a second SRS symbol. Determine an offset of the second SRS symbol based on a difference between a first radio chain of the UE and a second radio chain of the UE. Map the first SRS symbol and the second SRS symbol to an antenna port of the first radio chain of the UE. The UE transmits the first SRS symbol to a base station via the antenna port of the first antenna chain, and then applies the offset of the second SRS symbol to the first radio chain. In the case where the offset is applied to the first radio chain, the UE transmits the second SRS symbol to the base station via the antenna port of the first radio chain. Then, the UE and the base station can communicate based on channel state information determined using at least the first SRS symbol and the second SRS symbol.

[0005] In other aspects, a method for implementing adaptive sounding reference signal mapping using multiple radio chains of a user equipment includes generating a sequence of sounding reference signal (SRS) symbols corresponding to four respective antennas of the multiple radio chains, the four respective antennas including at least a first antenna, a second antenna, a third antenna, and a fourth antenna. Determine a first offset of a third SRS symbol in the SRS symbols based on a difference between a first radio chain of the first antenna and a third radio chain of the third antenna. Determine a second offset of a fourth SRS symbol based on a difference between a second radio chain of the second antenna and a fourth radio chain of the fourth antenna. Map the first SRS symbol and the third SRS symbol in the SRS symbols to the first radio chain of the first antenna, and map the second SRS symbol and the fourth SRS symbol in the SRS symbols to the second radio chain of the second antenna. The UE transmits the first SRS symbol to the base station via the first radio chain of the first antenna, and transmits the second SRS symbol to the base station via the second radio chain of the second antenna. Then, apply the first offset to the first radio chain of the first antenna and apply the second offset to the second radio chain of the second antenna. Then, the UE transmits the third SRS symbol to the base station via the first antenna of the first radio chain when applying the first offset; and transmits the fourth SRS symbol to the base station via the second antenna of the second radio chain when applying the second offset.

[0006] In other aspects, a method for enabling a user equipment to perform adaptive sounding reference signal mapping includes characterizing radio chains of a plurality of antennas of a user equipment (UE) to provide corresponding radio chain information. The method then assigns antennas of receive-only radio chains to antennas of transmit-capable radio chains based on the corresponding radio chain information. An offset between the receive-only radio chains and the transmit-capable radio chains is determined based on the corresponding radio chain information. The offset information is then stored in a memory of the UE to enable mapping of sounding reference signal symbols from antennas of the receive-only radio chains to antennas of the transmit-capable radio chains.

[0007] Details of one or more implementations for improving channel estimation using adaptive sounding reference signal mapping are set forth in the drawings and the following description. Other features and advantages will be apparent from the detailed description, the drawings, and the claims. This summary is provided to introduce the subject matter further described in the detailed description and the drawings. Accordingly, this summary should not be considered as describing essential features nor as limiting the scope of the subject matter of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure describes devices and techniques for adaptive sounding reference signal mapping for improving channel estimation with reference to the following drawings. The use of the same or similar reference numerals throughout the description and the drawings may indicate similar features or components:

[0009] Figure 1 An example operating environment in which various aspects of adaptive sounding reference signal mapping may be implemented;

[0010] Figure 2 An example block diagram of a network entity in which various aspects of adaptive sounding reference signal mapping may be implemented;

[0011] Figure 3 An example configuration of components for implementing adaptive sounding reference signal mapping according to one or more aspects;

[0012] Figure 4 An example antenna port mapping for transmitting sounding reference signal symbols according to one or more aspects;

[0013] Figure 5 An example wireless network environment in which a user equipment may transmit sounding reference signals to a base station according to one or more aspects;

[0014] Figure 6 An example resource grid and time slot of time and frequency resources in which sounding reference signal symbols may be mapped according to one or more aspects;

[0015] Figure 7Illustrates another example of a resource grid in which time and frequency resources for mapping sounding reference signal symbols can be mapped according to one or more aspects;

[0016] Figure 8 Illustrates an example control and signaling diagram for implementing adaptive sounding reference signal mapping according to one or more aspects;

[0017] Figure 9 Illustrates an example method for adaptive sounding reference signal mapping according to one or more aspects;

[0018] Figure 10 Illustrates an example method for mapping offset sounding reference signal symbols to corresponding antennas according to one or more aspects;

[0019] Figure 11A and 11B Illustrates an example method of aspects for enabling a user equipment to perform adaptive sounding reference signal mapping;

[0020] Figure 12 Depicts an example graph of the improved throughput performance of a user equipment provided by adaptive sounding reference signal mapping according to the described aspects;

[0021] Figure 13 Illustrates an example electronic device of a technology in which adaptive sounding reference signal mapping can be implemented according to one or more aspects;

[0022] Figure 14 Illustrates an example system-on-chip (SoC) environment of a technology in which adaptive sounding reference signal mapping can be implemented; and

[0023] Figure 15 Illustrates an example configuration of a wireless communication processor for various aspects in which adaptive sounding reference signal mapping can be implemented. Detailed Description

[0024] Prior art for estimating communication channels is typically limited by the hardware configuration of user equipment (UE) that transmits channel sounding signals to a base station. Generally, the base station can use the channel sounding signals transmitted by the UE to estimate the communication channel, and the base station determines the configuration for transmitting downlink communication to the UE based thereon (e.g., beamforming and precoding configurations). However, due to the asymmetric receive and transmit path configurations of most UEs, the accuracy of the base station's estimation of the communication channel may be limited with respect to the number of antennas supported by the UE. For example, a UE may include multiple antennas (e.g., four antennas) and hardware for receiving multiple-input multiple-output (MIMO) or implementing high-order receive diversity (HORxD) modes, but may only support transmission via a few antennas (e.g., two antennas) due to cost and space limitations associated with the transmitter and antenna switching circuitry. Thus, although having multiple antennas for improving the reception of downlink communication from the base station, the UE may only be able to transmit channel sounding signals via one or two transmit antennas. In the absence of channel sounding signals from the corresponding receive antennas, the accuracy of the base station's channel estimation is limited to the uplink path of the UE transmit antennas. Accordingly, the downlink transmission configuration of the base station determined based on the sounding signal uplink path is generally suboptimal and may result in reduced downlink data throughput of the UE.

[0025] Compared to the foregoing techniques, the present disclosure describes aspects of an adaptive sounding reference signal mapping for improving channel estimation. Generally, the described aspects enable a UE to implement an adaptive channel sounding process in which the UE can approximate the transmission of additional sounding reference signal (SRS) symbols from antennas that are not coupled to the transmit chain of the UE (e.g., receive-only antennas) to improve channel estimation. In other words, the UE can utilize the resources of the air interface that map SRS symbols to those corresponding to receive-only antennas and apply an offset to the transmit chain coupled to different antennas such that the UE can effect the sounding of another uplink path to the base station. By doing so, the additional SRS symbols approximating different uplink paths can enable the base station to estimate the characteristics of the communication channel with higher accuracy, which enables a more precise downlink channel configuration and an increase in the downlink throughput of the UE.

[0026] Upon review, the UE can transmit an SRS symbol from each antenna as part of a channel estimation process in which the base station estimates the channel quality corresponding to each communication path when implementing a multi-antenna scheme for communication between the UE and the base station. However, as described with respect to adaptive sounding reference signal mapping, the SRS symbol or corresponding SRS port does not have to be directly mapped to each physical antenna of the UE. In other words, for different UE antennas among the UE antennas, the SRS symbol is mapped to different subcarriers of the air interface resource grid to reduce interference. Additionally, there are various SRS configurations that the UE can implement based on the UE hardware and the sounding process requests of the base station.

[0027] These SRS configurations typically include 1T2R, 1T4R, 2T2R, 2T4R, or T = R, where "T" represents a viable antenna port of the transmit chain (Tx antenna or radio chain capable of transmitting), and "R" represents a viable antenna port of the receive chain (Rx antenna or radio chain only for receiving). In the context of various SRS symbol transmissions and UE configurations, 1T2R is one Tx chain that can transmit an SRS symbol through two receive antennas, 1T4R is one Tx chain that can transmit an SRS symbol through four receive antennas, 2T2R are two Tx chains that can transmit an SRS symbol through two receive antennas, and 2T4R are two Tx chains that can transmit an SRS symbol through four receive antennas. Thus, in order to probe four different communication channels using the above techniques, the UE must include an antenna switching circuitry that physically couples one or two transmit chains to all four receive antennas of the UE. As described above, adding such an antenna switching circuitry (e.g., an 1T4R or 2T4R support switching circuitry) to the UE can be very costly in terms of cost and PCB design space, specifically to cover all combinations of frequency bands. Additionally, the path loss associated with the additional switching circuitry (e.g., the cumulative insertion loss of the entire RF front end) may also degrade the RF performance, resulting in a minimal gain (if any) by adding an additional switching circuit for an additional transmit radio path.

[0028] To address these and other issues, the described aspects of adaptive sounding reference signal mapping enable a UE to achieve approximate channel sounding of more communication paths than the UE physically has available for uplink transmission. For example, according to one or more aspects, a UE may use a 1T2R hardware configuration to achieve 1T4R channel estimation, or use a 2T2R hardware configuration to achieve 2T4R channel estimation. To this end, the UE may utilize the fact that the mapping of the UE's SRS symbols or SRS transmit ports is not explicitly visible to the receiving base station of the network; rather, these symbols or ports are treated by the base station as an integrated part of the overall communication channel. By way of example, the base station may request that the UE transmit a set of four SRS symbols for sounding the communication channel, and then determine a configuration (e.g., precoder matrix) for uplink transmission or a configuration (e.g., beamforming pattern) for downlink transmission over the communication channel based on adaptive sounding via two antennas.

[0029] To implement adaptive sounding reference signal mapping, the UE may characterize the differences between its transmit and receive radio paths, such as by measuring and recording the receive performance metrics between the first / third and second / fourth radio paths. Based on these performance metrics, the UE may determine the corresponding offsets between the transmit radio paths (e.g., the first and second radio paths) and the receive radio paths (e.g., the third and fourth radio paths). During the channel sounding process, the UE manages the mapping of SRS symbols for all antennas on the SRS transmit antenna ports. By way of illustration, the UE generates a set of SRS symbols and transmits the first and second SRS symbols via the respective antenna ports of the first and second radio paths. The UE then applies an offset for the third and fourth SRS symbols by adjusting the respective path gains of the first and second radio chains. When applying the offset, the UE transmits the third and fourth SRS symbols via the respective antenna ports of the first and second radio paths to effectively approximate channel sounding of the third and fourth radio paths. By doing so, the UE may reduce the channel estimation error caused by the parametric increment between the primary / secondary radio paths and the third / fourth radio paths. In some cases, the resulting channel estimation approximating 1T4R or 2T4R channel sounding provided by the described aspects effectively increases the downlink throughput to the UE by up to 15% relative to 1T2R channel sounding. These are just a few examples of adaptive sounding reference signal mapping for improving channel estimation; other examples are described in the present disclosure.

[0030] In various aspects, a user equipment (UE) generates a set of sounding reference signal (SRS) symbols, the SRS symbols including at least first and second SRS symbols (e.g., two SRS symbols in a sequence of four SRS symbols). An offset of the second SRS symbol is determined based on a difference between a first radio link and a second radio link of the UE. The first SRS symbol and the second SRS symbol (e.g., the offset SRS symbol) are then mapped to an antenna port (e.g., a physical antenna port) of the first radio link of the UE. The UE transmits the first SRS symbol to a base station via the antenna port of the first radio link of the UE and transmits the second SRS symbol to the base station via the antenna port of the first radio link when an offset is applied to the first radio link. In some cases, the UE performs similar operations on third and fourth SRS symbols via the first radio link or a third radio link, which can effectively approximate 1T4R or 2T4R channel sounding. Based on channel information determined from at least two SRS symbols, the UE conveys uplink or downlink signaling or information with the base station. By doing so, the UE can improve channel estimation for uplink and / or downlink communication, which in turn can achieve increased communication throughput between the UE and the base station.

[0031] The following discussion describes an operating environment, techniques that may be employed in the operating environment, and various apparatuses or systems that may embody components of the operating environment. In the context of the present disclosure, the operating environment is mentioned only by way of example.

[0032] Example environment

[0033] Figure 1FIG. illustrates an example operating environment 100 in which various aspects of an adaptive sounding reference signal (SRS) mapping for improving channel estimation can be implemented. Generally, example environment 100 includes a user equipment 110 (UE 110), which can communicate with a base station 120 (illustrated as base stations 121, 122, 123, and 124) via a wireless communication link 130 (e.g., a wireless link or radio link) illustrated as wireless links 131 and 132. For simplicity, UE 110 is implemented as a smartphone, but can be implemented as any suitable computing or electronic device, such as a smartwatch, a mobile communication device, a modem, a cellular phone, a gaming device, a navigation device, a media device, a laptop computer, a desktop computer, a tablet computer, a smart appliance, a vehicle-based communication system, an Internet of Things (IoT) device (e.g., a sensor node, a controller / actuator node, a combination thereof), etc. The base station 120 (e.g., an evolved universal terrestrial radio access network Node B, an E-UTRAN Node B, an evolved Node B, an eNodeB, an eNB, a next-generation Node B, a gNode B, a gNB, etc.) can be implemented in a macro cell, a micro cell, a small cell, a pico cell, etc., or any combination thereof.

[0034] The base station 120 communicates with the UE 110 via wireless links 131 and 132 (e.g., radio links or wireless channels), which can be implemented as any suitable type of wireless link. Wireless links 131 and 132 include control and data communications, such as a downlink of data and control information transmitted from the base station 120 to the UE 110, an uplink of other data and control information transmitted from the UE 110 to the base station 120, or both. The wireless link 130 can include one or more wireless links (e.g., radio links) or bearers implemented using any appropriate communication protocol or standard, or a combination of communication protocols or standards, such as the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE), LTE Advanced, 5th Generation New Radio (5G NR), 6th Generation (6G), etc. Multiple wireless links 130 can be aggregated in carrier aggregation (CA) to provide a higher data rate for the UE 110. Multiple wireless links 130 from multiple base stations 120 can be configured for coordinated multi-point (CoMP) communication with the UE 110. Additionally, multiple wireless links 130 can be configured for dual connectivity (DC) (e.g., dual-carrier or multi-carrier), single radio access technology dual connectivity (SR-DC), or multi-radio access technology dual connectivity (MR-DC).

[0035] Base stations 120 together form a radio access network 140 (e.g., RAN, evolved universal terrestrial radio access network, E-UTRAN, 5G NR RAN, or NR RAN). RAN 140 is illustrated as NR RAN 141 and E-UTRAN 142. Base stations 121 and 123 in NR RAN 141 are connected to the fifth generation core 150 (5GC 150) network. Base stations 122 and 124 in E-UTRAN 142 are connected to the evolved packet core 160 (EPC 160). Additionally or alternatively, base station 122 may be connected to both the 5GC 150 and EPC 160 networks.

[0036] Base stations 121 and 123 are connected to 5GC 150 at 101 and 102 respectively via the NG2 interface for control plane signaling and using the NG3 interface for user plane data communication. Base stations 122 and 124 are connected to EPC 160 at 103 and 104 respectively using the S1 interface for control plane signaling and user plane data communication. Optionally or additionally, if base station 122 is connected to the 5GC 150 and EPC 160 networks, base station 122 uses the NG2 interface for control plane signaling and is connected to 5GC 150 via the NG3 interface for user plane data communication at 105.

[0037] In addition to the connections to the core network, base stations 120 may also communicate with each other. For example, base stations 121 and 123 communicate via the Xn interface at 106, and base stations 122 and 124 communicate via the X2 interface at 107 to exchange user plane and control plane data. The interface or link at 105 or 106 between base stations 120 may be implemented as any suitable type of link, such as a millimeter wave link, a sub-millimeter wave link, or a free space optical (FSO) link. At least one base station 120 (base station 121 and / or base station 123) in NR RAN 141 may communicate with at least one base station 120 (base station 122 and / or base station 124) in E-UTRAN 142 using the Xn interface 107. In various aspects, base stations 120 in different RANs (e.g., base stations 120 of each RAN) communicate with each other using an Xn interface such as Xn interface 108.

[0038] 5GC 150 includes an Access and Mobility Management Function 152 (AMF 152), which provides control plane functions such as registration and authentication, authorization, and mobility management of multiple UEs 110 in a 5G NR network. The EPC 160 includes a Mobility Management Entity 162 (MME 162), which provides control plane functions such as registration and authentication, authorization, or mobility management of multiple UEs 110 in an E-UTRA network. The AMF 152 and the MME 162 communicate with the base station 120 in the RAN 140 and also use the base station 120 to communicate with multiple UEs 110.

[0039] Reference Figure 1 , according to one or more aspects, the UE 110 further includes a Sounding Reference Signal Port Mapper 170 (SRS Port Mapper 170) and Radio Link Information 172. Generally, the SRS Port Mapper 170 can modify UE capability messages, determine offset information of radio links, map SRS ports or SRS symbols to physical antenna ports of the UE 110, apply an offset to a transmitting radio link, manage the transmission of SRS symbols, and so on. In some aspects, the SRS Port Mapper 170 determines the offset based on the difference between a first radio link and a second radio link of the UE 110. The UE 110 can store this offset and other radio link information (e.g., reference information or measurements) as the Radio Link Information 172. As part of a channel sounding process, the SRS Port Mapper 170 can map corresponding first and second SRS symbols of the first radio link and the second radio link to an antenna port of the first radio link. Then, the UE 110 transmits the first SRS symbol via the antenna port of the first radio link. Then, the SRS Port Mapper 170 applies an offset to the first radio link, which can effectively account for the difference between the first radio link and the second radio link. When the offset is applied, the UE 110 transmits the second SRS symbol via the antenna port of the first radio link.

[0040] Alternatively or additionally, the SRS Port Mapper 170 can perform similar operations on a third radio link and a fourth radio link of the UE 110 such that two SRS symbols are transmitted via an antenna port of the third radio link. This may effectively approximate a channel sounding process that includes SRS symbols for radio links of the UE 110 that cannot transmit (e.g., receive-only radio links). By doing so, the SRS Port Mapper 170 can enable the base station to estimate the channel with improved accuracy when using at least the first and second SRS symbols transmitted via the antenna port of the first radio link. The use and implementation of the SRS Port Mapper 170 can vary according to one or more aspects and are described throughout the disclosure.

[0041] Example Device

[0042] Figure 2 FIG. 200 is an example diagram of a user equipment and a serving cell base station. Generally, the apparatus diagram 200 depicts network entities that can implement various aspects of an adaptive sounding reference signal mapping for improving channel estimation. Figure 2 Corresponding examples of UE 110 and base station 120 are shown. For visual simplicity, UE 110 and base station 120 may include additional functions and interfaces that are omitted from Figure 2 UE 110 includes an antenna 202, a radio frequency front end 204 (RF front end 204), and a wireless transceiver 206 (e.g., an LTE transceiver, a 5G NR transceiver, or a 6G transceiver) for communicating with base station 120 in NR RAN 141 and / or E-UTRAN 142. UE 110 may also include one or more additional transceivers (e.g., a local wireless network transceiver) for communicating with another UE or a local network entity via one or more local wireless networks (e.g., WLAN, WPAN, Bluetooth TM , NFC, Wi-Fi-Direct, IEEE802.15.4, ZigBee, Thread, millimeter wave, sub-millimeter wave, FSO, radar, lidar, sonar, ultrasonic). The RF front end 204 of UE 110 may couple or connect one or more of the wireless transceivers 206 in UE 110 to the antenna 202 to facilitate various types of wireless communication.

[0043] The antenna 202 of UE 110 may include an array of multiple antennas configured to be similar or different from each other. The antenna 202 and the RF front end 204 may be tuned to and / or tunable to one or more frequency bands defined by 3GPP LTE, 5G NR, or 6G communication standards and implemented by the wireless transceiver 206. Additionally, the antenna 202, the RF front end 204, and the wireless transceiver 206 (e.g., a 5G NR transceiver) may be configured to support beamforming for transmitting and receiving communications with base station 120. By way of example and not limitation, the antenna 202 and the RF front end 204 may be implemented to operate in sub-gigahertz frequency bands, below 6 GHz frequency bands, and / or above 6 GHz frequency bands (e.g., 57 to 64 GHz, 28 GHz, 38 GHz, 71 GHz, 81 GHz, or 92 GHz frequency bands) defined by 3GPP LTE and 5G NR communication standards. Additionally, the RF front end 204 may be tuned to and / or tunable to one or more frequency bands defined and implemented by the local wireless network transceiver of UE 110 to support transmitting and receiving communications with other UEs or entities associated with the local wireless network.

[0044] The UE 110 may also include sensors (not shown) that may be implemented to detect various environmental or system attributes of the UE 110, such as temperature, location, orientation, power supply, power usage, battery status, etc. Thus, the sensors of the UE 110 may include any one or combination of a temperature sensor, a Global Navigation Satellite System (GNSS) sensor, an accelerometer, a thermistor, a battery sensor, and a power usage sensor.

[0045] The UE 110 also includes a processor 208 and a computer-readable storage medium 210 (CRM 210). The processor 208 may be a single-core or multi-core processor implemented with a homogeneous or heterogeneous core architecture. The processor 208 may include a hardware-based processor implemented as hardware-based logic, circuitry, processing cores, etc. In some aspects, the functions of the processor 208 and other components of the UE 110 are provided via an integrated processing, communication, and / or control system (e.g., a system-on-chip), which may enable various operations of the UE 110 in which the system is embodied. The computer-readable storage medium described herein does not include propagated signals. The CRM 210 may include any suitable memory or storage device for storing the device data 212 of the UE 110, such as random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory. The device data 212 includes user data, multimedia data, beamforming codebooks, applications, and / or the operating system of the UE 110, which may be executed by the processor 208 to enable user plane communication, control plane signaling, and user interaction with the UE 110.

[0046] In aspects of adaptive sounding reference signal mapping, the CRM 210 of the UE 110 may also include an instance of the SRS port mapper 170 and an instance of the radio link information 172. Generally, the radio link information 172 may include information related to performance metrics or characteristics of the radio link or radio path of the wireless transceiver 206, RF front end 204, and / or antenna 202 of the UE 110. In this example, the radio link information 172 includes reference information 214 and offset information 216 for one or more radio links of the UE 110. The reference information 214 may include corresponding measurement, calibration, or performance information (e.g., total isotropic sensitivity (TIS)) of one or more radio links or communication paths of the UE 110. The offset information 216 may include offset information indicating the difference between any two radio links, which may include the difference in the corresponding reference information 214 of the two radio links. For example, for any two radio links or communication paths, the offset information 216 may indicate differences in receive sensitivity, RF path loss, transmit power, etc.

[0047] Alternatively or additionally, the SRS port mapper 170 may be implemented in whole or in part as hardware logic or circuitry integrated with or separate from other components of the UE 110. Generally, the SRS port mapper 170 of the UE 110 may characterize the difference between a first radio link (e.g., capable of transmitting) and a second radio link (e.g., only receiving) of the UE, and determine an offset of the radio link that enables the first radio link to approximate the performance of the second radio link based on the difference. The SRS port mapper 170 may then map the respective SRS symbols of the first and second radio links to the antenna ports of the first radio link. After transmitting the first SRS symbol to the base station via the first radio link, the SRS port mapper 170 applies the offset to the first radio link and transmits the second SRS symbol to the base station via the antenna port of the first radio link while applying the offset. By doing so, the SRS port mapper 170 enables the base station to estimate the communication channel between the UE 110 and the base station with higher accuracy based on the first and second SRS symbols than by transmitting only one SRS symbol via the antenna port of the first radio link. Alternatively or additionally, the SRS port mapper 170 may edit or modify the UE capabilities (not shown) to indicate to the base station 120 that the UE 110 supports a channel sounding process with more antennas (e.g., four antennas for 1T4R or 2T4R sounding) than the antennas of a UE capable of transmitting SRS symbols (e.g., two antennas for 1T2R or 2T2R based on the actual hardware configuration of the UE). The implementation and use of the SRS port mapper 170 of the UE 110 vary and are described throughout the disclosure.

[0048] Aspects and functions of the UE 110 may be managed by operating system control presented via an application programming interface (API, not shown). In some aspects, the SRS port mapper 170 accesses the API or API services of the UE 110 to control aspects and functions of the user equipment or its transceiver. For example, the SRS port mapper 170 may access or utilize the wireless transceiver 206 to modify transceiver (e.g., modem or radio) configuration information, UE capability information, calibration information, signal quality measurements, etc. The CRM 210 also includes a communication manager (not shown). The communication manager may also be implemented in whole or in part as hardware logic or circuitry integrated with or separate from other components of the UE 110. In at least some aspects, the communication manager configures the RF front end 204, the wireless transceiver 206, and / or other transceivers of the UE 110 to implement the techniques for adaptive sounding reference signal mapping for improved channel estimation as described herein.

[0049] As Figure 2As shown in [description], the block diagram of base station 120 includes a single network node (e.g., gNode B or eNode B). The functions of base station 120 can be distributed across multiple network nodes or devices, and can be distributed in any manner suitable for performing the functions described herein. Base station 120 includes antennas 252, a radio frequency front end 254 (RF front end 254), and one or more wireless transceivers 256 (e.g., an LTE transceiver, a 5G NR transceiver, or a 6G transceiver) for communicating with UE 110. The RF front end 254 of base station 120 can couple or connect the wireless transceiver 256 to the antennas 252 to facilitate various types of wireless communication. The antennas 252 of base station 120 can include an array of multiple antennas configured to be similar to or different from each other. The antennas 252 and the RF front end 254 can be tuned to and / or be tunable to one or more frequency bands defined by 3GPP LTE, 5G NR, or 6G communication standards and implemented by the wireless transceiver 256. Additionally, the antennas 252, the RF front end 254, and / or the wireless transceivers 256 can be configured to support beamforming such as massive MIMO for transmitting and receiving communications with any UE 110 in the network cell provided by the base station.

[0050] Base station 120 also includes a processor 258 and a computer-readable storage medium 260 (CRM 260). The processor 258 can be a single-core or multi-core processor composed of various materials such as silicon, polysilicon, high-K dielectrics, copper, etc. The CRM 260 can include any suitable memory or storage device for storing the device data 262 of base station 120, such as RAM, SRAM, DRAM, NVRAM, ROM, or flash memory. The device data 262 includes network scheduling data, radio resource management data, beamforming codebooks, applications, and / or the operating system of base station 120, which can be executed by the processor 258 to enable communication with UE 110 operating on one or more RANs 140 provided by the base station.

[0051] In various aspects, the CRM 260 of base station 120 also includes a channel and beam management function 264. Alternatively or additionally, the channel and beam management function 264 can be implemented, in whole or in part, as hardware logic or circuitry integrated with or separate from other components of base station 120 (e.g., radio transceiver 256). Generally speaking, the channel and beam management function 264 enables the base station to perform channel sounding procedures and determine the communication configuration for downlink or uplink communication between base station 120 and UE 110. For example, base station 120 can use the channel and beam management function 264 to request a channel sounding procedure from UE 110, estimate the characteristics of the radio channel, generate channel state information, determine a precoding matrix, select a beamforming mode or direction, etc. The use and implementation of the channel and beam management function 264 vary and are described throughout the disclosure.

[0052] The CRM 260 also includes a base station manager 266 to manage the various functions of base station 120. Alternatively or additionally, the base station manager 266 can be implemented, in whole or in part, as hardware logic or circuitry integrated with or separate from other components of base station 120. In at least some aspects, the base station manager 266 configures the antennas 252, RF front end 254, or radio transceiver 256 of base station 120 for communication with UE 110 and for communication with the core network. Base station 120 includes an inter-base station interface 268, such as an Xn and / or X2 interface, and the base station manager 266 configures the inter-base station interface to exchange user plane and control plane data between another base station 120 to manage the communication between base station 120 and UE 110. Base station 120 includes a core network interface 270, and the base station manager 266 configures the core network interface to exchange user plane and control plane data with core network functions and entities.

[0053] Figure 3 An example configuration of components for implementing various aspects of an adaptive sounding reference signal mapping for improved channel estimation is illustrated at 300. The illustrated components can be implemented in any suitable device, system, or apparatus such as a user equipment, user device, mobile device, mobile station, etc. The components and architecture of the example configuration are presented as non-limiting examples of ways in which various entities for implementing an adaptive sounding reference signal mapping for improved channel estimation can be implemented. Thus, the aspects described herein can be applied or extended to any suitable combination or configuration of components and / or circuitry for implementing various features of an adaptive sounding reference signal mapping for improved channel estimation.

[0054] In this example, the components are illustrated in the context of UE 110, which can be as referenced Figure 2as described or otherwise implemented throughout this disclosure. Generally, UE 110 includes a modem 302 that provides a wireless communication interface through which the UE 110 transmits user plane and / or control plane information to a base station 120 of a wireless network. The modem 302 may be implemented as a broadcast card, a radio module, a modem baseband processor, a wireless communication processor, a system-on-chip, an LTE transceiver, a 5G NR transceiver, or a 6G transceiver or a part thereof, such as any one of the components described with reference to Figure 1 , Figure 2 or Figures 4 to 15 . To facilitate wireless communication, the modem 302 implements various data and signal processing functions, which may include encoding, decoding, modulation, demodulation, analog-to-digital conversion, digital-to-analog conversion, etc. In some cases, the modem 302 is configured as a multi-mode multi-band modem, and the transceiver is embodied through the modem to at least partially support wireless communication using multiple radio access technologies (RATs) (e.g., LTE, 5G NR, 6G) in multiple frequency bands.

[0055] Generally, the modem 302 includes a transmitter and a receiver (collectively illustrated here as an example of a wireless transceiver 206) to communicate in one or more RATs and / or one or more frequency bands. As Figure 3 shown, the corresponding transmit and receive functions of the wireless transceiver 206 include a radio chain 304 (or communication path) that couples between the wireless transceiver 206, the RF front end 204, and / or the antenna 202 of the UE 110. The radio chain 304 or communication path of the wireless transceiver may be configured with transmit capabilities and / or receive capabilities. Thus, the radio chain 304 may include an example of a transmit chain 306, an example of a receive chain 308, or both a transmit chain and a receive chain to support transmit and receive capabilities.

[0056] The transmit chain 306, which may also be referred to as the transmit path, operably couples the transmitter (e.g., transmit port) of the modem 302 to the RF front end 204 and / or the antenna 202 of the UE 110. In various aspects, the transmit chain 306 includes corresponding examples of transmitter components, functions, and circuitry (not shown) that provide a chain or path through which the modem 302 transmits user and / or control information via a channel or carrier signal over a wireless medium. For example, an instance of the transmit chain 306 may include a collection of transmitter components and circuitry that encode, modulate, up-convert, amplify, route, and transmit a single or individual stream or channel of signaling and / or data. Thus, the transmit chain 306 may include one of the transmitter module or portion of the modem 302, digital-to-analog conversion circuitry, RF transceiver circuitry, RF switches and duplexers of the RF front end 204, antenna ports 310, and the antenna 202.

[0057] The receive chain 308, which may also be referred to as the receive path, operably couples the receiver (e.g., receive port) of the modem 302 to the RF front end 204 and / or the antenna 202 of the UE 110. In various aspects, each receive chain 308 may include corresponding examples of receiver components, functions, and circuitry that provide a chain or path through which the modem 302 receives user and / or control information via a channel or carrier signal over a wireless medium. For example, an instance of the receive chain 308 may include a collection of receiver components and circuitry that decode, demodulate, down-convert, amplify, filter, route, and receive a single or individual stream or channel of signaling and / or data. Thus, the receive chain 308 may include one of the receiver module or portion of the modem 302, analog-to-digital conversion circuitry, RF transceiver circuitry, RF switches and duplexers of the RF front end 204, antenna ports 310, and the antenna 202.

[0058] In some aspects, the UE 110 includes one or two transmit radio chains 304 or transmitter paths that can be switched to at least two of the antennas 202 for transmit operations. In other words, the wireless transceiver 206 and the RF front end 204 of the UE 110 may be configured to physically support a 1T2R or 2T2R antenna switching configuration for channel sounding procedures or other transmissions. In this example, the UE 110 includes two transmit radio chains (e.g., 2T2R), although aspects of adaptive sounding reference signal mapping may be implemented with one transmit radio chain (e.g., 1T2R). Refer to Figure 3, the first radio link 0 304-0 of the UE 110 is configured for both reception operations and transmission operations, and includes components of a transmit chain 0306-0 and a receive chain 308-0 that can be coupled to a first antenna port 310-0. The second radio link 1 304-1 of the UE 110 is also configured for both reception operations and transmission operations, and includes components of a transmit chain 2 306-1 and a receive chain 308-1 that can be coupled to a second antenna port 310-1 for transmission and / or reception operations.

[0059] Additionally, the third radio link 2 304-2 of the UE 110 is configured for reception operations, and includes components of a receive chain 1 308-2 that can be coupled to a third antenna port 310-2. The fourth radio link 3 304-3 of the UE110 is also configured for reception operations, and includes components of a receive chain 3 308-3 that can be coupled to a fourth antenna port 310-3. Although not shown, the components of the RF front end 204 can enable each of the radio links 304-0 to 304-3 to be coupled to the corresponding antenna ports 310-0 to 310-3 of the UE 110. Thus, in this example UE 110 configuration, two of the radio links 304 can transmit signals and communications to the base station 120, and all four radio links 304 can receive signaling and communications from the base station 120.

[0060] Figure 4 An example antenna port mapping for transmitting sounding reference signal symbols according to one or more aspects is illustrated at 400. As described herein, a UE may implement an adaptive SRS symbol mapping to achieve 1T4R channel estimation with a 1T2R hardware configuration, or 2T4R channel estimation with a 2T2R hardware configuration, etc. To this end, the UE may utilize the fact that the mapping of SRS symbols or SRS transmit ports by the UE is not explicitly visible to the receiving base station of the network; rather, these symbols or ports are treated by the base station as an integrated part of the overall communication channel. In aspects of adaptive sounding reference signal mapping, the UE transmits SRS symbols via the propagation channel 402 (H n ) of the wireless medium between the UE 110 and the base station 120.

[0061] By way of review, the channel model H n between a base station (e.g., gNB or eNB) and a UE is rx composed of antenna matrices F tx and F n as well as per-cluster channel matrices h

[0062]

[0063] Equation 1: Communication channel model

[0064] In the context of the communication channel between the base station and the UE, base station antenna F tx and UE antenna F rx are an integral part of the channel such that F tx and F rx include both the respective antenna elements (arrays) and radio chains of the UE and the base station. The propagation path between the UE and the base station can be divided into two parts H n = H n_p * H n_t , where the first part H n_p includes the air part H n and F tx (gNB / eNB) and the second part H n_t includes the F of the UE rx . Generally speaking, the first part is H n_p that includes the air part of the channel, and the second part H n_t that is greater than the radio chain and the corresponding antenna of the UE.

[0065] In the context of the main transmitting antenna (e.g., the 202-0 first antenna) and the receive-only antenna (e.g., the 202-2 third antenna), H 1_p and H 3_p can represent the respective air propagation path parts, and H 1_t and H 3_t can represent the respective UE radio chains and corresponding antennas (e.g., radio chain 0 304-0 and antenna 202-0 (main transmit chain), and radio chain 304-2 and antenna 202-2 (third receive chain)). Regarding the channel differences between these communication paths, most of the signal propagation distance is the air part of the channel between the base station and the UE. Additionally, the antenna 252 of the base station usually has a higher directivity (e.g., direction gain). Therefore, the H 1_p and H 3_p parts have a much greater impact on the channel time, frequency, polarization, and spatial selectivity of the four domains that are usually the channel model.

[0066] From channels H 1_t and H 3_tFrom the perspective of the UE-centric part, the channel differences are caused by variations in the corresponding amplifier gains, noise figures, antenna patterns, or antenna gains of the UE's radio chains. Thus, relative to the air part of the channel, the conductive part of the channel associated with the corresponding characteristics of the UE radio chains is smaller, enabling the aspects described to appropriately account for or compensate for differences between radio chains. For example, UE 110 may be implemented with an almost omnidirectional antenna, where the differences in pattern and / or gain variations between antennas are relatively small. Thus, from the perspective of the UE, the observed channels to the base station (e.g., gNB) through the main transmit antenna and the receive-only antenna (or other UE antenna pairs) look very similar, regardless of whether the propagation path is line-of-sight or strong multipath. In other words, the increment between H n_t is a much smaller part of the overall channel model H n which can be used to implement the aspects described, such that differences in the UE radio chains can be compensated for or resolved when performing the channel sounding process. Based on this channel analysis and by leveraging the fact that the SRS symbol mapping is not explicitly visible to the receiving base station of the network, the SRS port mapper 170 of UE 110 can manage the mapping of SRS symbols and the settings of the transmit chain to approximate the channel sounding process of the receive-only antenna. By doing so, the aspects of the adaptive SRS mapping described can improve channel estimation, yield higher throughput, and extend the network coverage of the UE.

[0067] As Figure 4 shown, UE 110 probes the propagation channel 402 by transmitting four SRS symbols 404-0 to 404-3 to the antenna array 252 of base station 120 via the propagation channel. For example, base station 120 may request that the UE transmit a set of four SRS symbols for channel sounding, which are then used to determine the configuration for uplink transmission (e.g., precoder matrix) or the configuration for downlink transmission (e.g., beamforming pattern). Although not shown, the four SRS symbols 404-0 to 404-3 may be transmitted via the one transmit-capable radio chain (e.g., 1T2R hardware) or two transmit-capable radio chains (e.g., 2T2R hardware) described.

[0068] As part of the channel sounding process, the SRS port mapper 170 maps the first SRS symbol 0 404-0 (or its SRS port) and the third SRS symbol 2 404-2 (or its SRS port) to the antenna port of antenna 0 202-0. The SRS port mapper 170 also maps the second SRS symbol 1 404-1 (or its SRS port) and the fourth SRS symbol 3 404-3 (or its SRS port) to the antenna port of antenna 1 202-1. Then, the UE 110 transmits the first SRS symbol 404-0 via the first antenna 202-0 and transmits the second SRS symbol 404-1 via the second antenna. In various aspects, the SRS port mapper 170 applies a first offset 406-1 to the transmit-capable radio chain to which the third SRS symbol 404-2 is mapped based on the radio chain information 172, and applies a second offset 406-2 to the transmit-capable radio chain to which the fourth SRS symbol 404-3 is mapped. In some cases, applying the offset includes adjusting the path gain of the first and / or second radio chains of the UE 110. When the offset is applied, the UE transmits the third SRS symbol 404-2 and the fourth SRS symbol 404-3 via the respective antenna ports of the first antenna 202-0 and the second antenna 202-1. As Figure 4 shown, the set of SRS symbols 404 traverses the propagation channel and the base station 120 receives the channel-affected SRS symbols 408-0 to 408-3 via the antennas 252 of the base station. Based on the received SRS symbols 408 that approximate channel sounding for four UE antennas 202-0 to 202-3, the base station estimates the characteristics of the propagation channel 402. In other words, the base station 120 can estimate the channel as if the UE 110 transmits the set of SRS symbols according to a 1T4R, 2T4R, or 4T=4R hardware configuration, even though the UE 110 includes a 1T2R or 2T2R hardware configuration.

[0069] As another example, consider Figure 5 , Figure 5FIG. illustrates an example wireless network environment 500 according to one or more aspects in which a user equipment may transmit sounding reference signals to a base station. Here, the SRS port mapper 170 enables the UE 110 to perform the process of sounding propagation channel 402 by transmitting four SRS symbols 408 through the channel via the primary antenna 202-0 and the secondary antenna 202-1 of the UE 110. As described herein, the UE 110 may transmit the third and fourth SRS symbols via the respective antenna ports of the first and second antennas (e.g., the radio paths capable of transmission) to effectively approximate the channel sounding of the third and fourth radio paths. By doing so, the UE may reduce the channel estimation error caused by the parameter increment between the primary / secondary radio paths and the third / fourth radio paths. In some cases, the resulting channel estimation of the approximate 1T4R or 2T4R channel sounding provided by the described aspects effectively increases the downlink throughput to the UE by up to 15% compared to 1T2R channel sounding.

[0070] Figure 6 FIG. illustrates an example time slot diagram 600 and an example resource grid 602 according to one or more aspects in which the time and frequency resources for mapping sounding reference signal symbols may be mapped. In this example, the UE 110 adaptively maps four SRS symbols 604-0 to 604-3 to the physical antenna ports of a 1T2R hardware configuration to perform 1T4R channel sounding. Here, the 1T2R hardware configuration may correspond to radio chain 0 304-0 of the UE 110, as well as antenna 0 202-0 and antenna 1 202-1, where the RF front end 204 supports physical switching between the radio chain and the antenna. Referring to the time slot diagram 600 and in the context of the time domain, the SRS port mapper 170 of the UE maps the first SRS 0 symbol 604-0 to the antenna port of ANT 0 202-0 (e.g., the primary TX antenna) for transmission during the first time slot (e.g., time slot n). The SRS port mapper 170 also maps the second SRS 1 symbol 604-1 to the antenna port of ANT 1 202-1 (e.g., the secondary TX antenna) for transmission during the first time slot. The third SRS 2 symbol 604-2 is also mapped to the antenna port of ANT 0202-0 for transmission during the first time slot, and the fourth SRS 3 symbol 604-3 is mapped to the antenna port of ANT 1 202-1 for transmission during a subsequent time slot (e.g., time slot n+1).

[0071] In the time domain and the frequency domain, as shown in resource grid 602, the SRS port mapper 170 maps four SRS symbols 604-0 to 604-3 across OFDM symbols and resource blocks for physical transmission by radio link 0 304-0 of the UE. Generally, 1T4R channel sounding is implemented by transmitting four SRS symbols through four SRS ports or four antenna ports, but it is not necessary to have four separate physical antenna ports. Different antenna ports logically share the same set of resource elements and the same basic SRS sequence. Therefore, the SRS port mapper can apply four different phase rotations, which is equivalent to applying cyclic shifts in the time domain, to separate the four SRS symbols 604-0 to 604-3 for transmission by one or two radio links and their corresponding antennas. In other words, the SRS port mapper 170 can apply four different phase rotations to a set of SRS resources to provide four different SRS symbols 604-0 to 604-3 corresponding to the SRS symbol sequence for 1T4R channel sounding.

[0072] As another example, consider Figure 7 , Figure 7 FIG. illustrates another example resource grid 700 that maps sounding reference signal symbols according to one or more aspects. In this example, the UE 110 adaptively maps four SRS symbols 702-0 to 702-3 to the physical antenna ports of a 2T2R hardware configuration to implement 2T4R channel sounding. Here, the 2T2R hardware configuration can correspond to radio link 0 304-0, radio link 1 304-1, antenna 0 202-0, and antenna 1 202-1 of the UE 110. Generally, the SRS port mapper 170 can be applied in a UE with a 2T2R hardware configuration with reference to a 1T2R hardware configuration (e.g., Figure 6) Aspects similar to the described aspects are used to enable 2T4R channel sounding. In other words, the SRS port mapper can apply a mapping similar to that described for the adaptive mapping of 1T4R channel sounding to implement 2T4R channel sounding with a 2T2R hardware configuration of UE110. Referring to the time and frequency resources of the resource grid 702, the SRS port mapper 170 of the UE maps the first SRS0 symbol 702-0 to the antenna port of ANT 0 202-0 (e.g., the primary TX antenna) for transmission by the first radio link 0 304-0. The SRS port mapper 170 also maps the second SRS 1 symbol 702-1 to the antenna port of ANT1 202-1 (e.g., the secondary TX antenna) for transmission by the second radio link 304-1. The third SRS 2 symbol 702-2 is also mapped to the antenna port of ANT 0202-0 for transmission by the first radio link 304-0, and the fourth SRS 3 symbol 702-3 is mapped to the antenna port of ANT 1 202-1 for transmission by the second radio link 304-1. By doing so, each of the two antennas of UE 110 simultaneously transmits a generally complex-valued weighted combination of two SRS symbols per time slot. The following aspects regarding the adaptive sounding reference signal mapping can also be implemented in the SRS port mapper with reference to Figure 6 and 7 the described adaptive SRS symbol mapping.

[0073] Example transactions of the adaptive sounding reference signal mapping

[0074] Figure 8 FIG. 800 illustrates an example signaling and control transaction diagram, which includes a combination of actions, signaling transactions, and / or control transactions that can be used to perform aspects of the adaptive sounding reference signal mapping, such as transmitting a plurality of SRS symbols including modified or offset SRS symbols via one antenna of the UE. In some aspects, the actions or transactions described with reference to FIG. 800 can be used in conjunction with entities as described with reference to Figures 1 to 6 or Figures 8 to 14 described or Figure 1 used together.

[0075] At 802, a UE (e.g., UE 110) determines UE RF capability information associated with a channel sounding procedure. The SRS port mapper of the UE may determine UE capability information that is different from the capabilities supported by the UE's hardware configuration. In some cases, when the UE's hardware is configured to support transmission with two or fewer antennas, the SRS port mapper generates or modifies the UE RF capability information to indicate that the UE supports transmission with at least three antennas (e.g., four receive antennas). For example, the SRS port mapper may generate or edit "supportedSRS-TxPortSwitch" to indicate support for 1T4R, 2T4R, or 4T=4R antenna switching hardware configurations. At 804, the UE transmits a UE RF capability information element to a base station (e.g., base station 120). The UE RF capability information may be transmitted as part of a UE capability message sent to the base station. Alternatively or additionally, the UE may transmit an indication that the UE is capable of transmitting via more antennas than supported by the UE's hardware configuration.

[0076] At 806, the base station determines the UE's UE SRS configuration. Based on the capabilities indicated by the UE, the base station may request one or more antenna switching configurations for the channel sounding procedure. The base station may also determine the SRS resource set used by the UE for the channel sounding procedure. For example, the base station may request that the UE transmit SRS symbols according to a 1T4R, 2T4R, or 4T=4R antenna switching hardware configuration. At 808, the base station transmits the UE SRS configuration to the UE. In some cases, as part of the channel sounding procedure, the base station transmits radio resource control (RRC) parameters that effectively cause the UE to configure and use SRS antenna switching (e.g., SRS-ResourceSet.usage=antennaSwitching). Alternatively or additionally, as part of a channel sounding request, the base station may send the UE SRS configuration.

[0077] At 810, the UE determines the offsets of two or more radio chains of the UE based on differences between the radio chains (e.g., including the communication paths of the respective antennas). The SRS port mapper of the UE may access the radio chain information of the UE to generate or determine the corresponding offsets of radio chain pairs. In some cases, the SRS port mapper determines the offset of a transmit-capable radio chain based on the difference between the transmit-capable radio chain and a receive-only radio chain.

[0078] At 812, the UE maps SRS symbol pairs in the SRS symbol set to the antenna ports of the UE. In the context of the SRS configuration requested by the base station, the first in the SRS symbol pair can correspond to a transmit-capable radio chain, while the second in the SRS symbol pair can correspond to a receive-only radio chain. In some cases, the SRS port mapper maps the SRS symbol pair to the antenna port of the first transmit chain and maps the SRS symbol pair to the antenna port of the second transmit chain (e.g., for a UE configured with 2T2R). In other cases, the SRS port mapper maps two pairs of SRS symbols to the antenna ports of the transmit chains of the UE (e.g., for a UE configured with 1T2R).

[0079] At 814, the UE transmits the SRS symbol set to the base station via the mapped antenna ports. In this example, the UE transmits the first and second SRS symbols via the respective first and second transmit-capable radio chains of the UE (e.g., the respective first SRS symbol to two pairs of SRS symbols). Then, the SRS port mapper of the UE applies an offset to the first and second transmit-capable radio chains of the UE. With the offset applied, the UE transmits the third and fourth SRS symbols via the respective first and second transmit-capable radio chains of the UE (e.g., the respective second SRS symbol to two pairs of SRS symbols). By doing so, the UE can use a 2T2R hardware configuration to approximate the transmission of SRS symbols according to a four-antenna channel sounding configuration (such as 1T4R, 2T4R, or 4T=4R configuration).

[0080] In other cases, the UE transmits the first SRS symbol via the first transmit-capable radio chain of the UE (e.g., the transmit chain switched to the first antenna). The UE also transmits the second SRS symbol via the second transmit-capable radio chain of the UE (e.g., the transmit chain switched to the first antenna). Then, the SRS port mapper of the UE applies a first offset to the first transmit-capable radio chain and, with the first offset applied, transmits the third SRS symbol via the first transmit-capable radio chain. Next, the SRS port mapper applies a second offset to the second transmit-capable radio chain and, with the second offset applied, transmits the fourth SRS symbol via the second transmit-capable radio chain. By doing so, the UE can use a 1T2R hardware configuration to approximate the transmission of SRS symbols according to a four-antenna channel sounding configuration (such as 1T4R, 2T4R, or 4T=4R configuration).

[0081] At 816, the base station estimates the channel between the UE and the base station based on a set of SRS symbols received from the UE. Because the set of SRS symbols transmitted according to aspects of the adaptive sounding reference signal mapping approximates an additional channel, the base station can estimate the channel more accurately than when using fewer SRS symbols or UE transmit chains. At 818, the base station determines a communication configuration based on the estimation of the channel. The base station can determine the configuration of the transmitter of the base station (e.g., beamforming mode or direction) and / or the configuration of the transmitter of the UE (e.g., precoder configuration). Generally, using the improved channel estimation enables the base station to determine the corresponding transmitter configuration that better matches the communication channel between the UE and the base station, which can increase the throughput of downlink or uplink communication.

[0082] At 820, the UE and the base station communicate based on the communication configuration of the base station. In some cases, the base station uses the downlink communication configuration determined from the adaptively mapped SRS symbols to transmit downlink signals or information to the UE. Alternatively or additionally, the UE uses the uplink communication configuration determined from the adaptively mapped SRS symbols to transmit uplink signals or information to the base station. As described herein, using the adaptive SRS symbol mapping can improve channel estimation, which in turn enables the determination of better communication configurations and / or increased throughput when communicating over the channel.

[0083] Example methods

[0084] According to one or more aspects of the adaptive sounding reference signal mapping for improving channel estimation, example methods 900 to 1100 are respectively referred to Figures 9 to 11B and described. Alternatively or additionally, various aspects of radio chain characterization and allocation for implementing the adaptive sounding reference signal mapping are described with reference to one or more methods. Generally, methods 900 to 1100 illustrate a set of operations (or actions) that can be performed (but not limited to) in the order or combination of operations shown herein. Additionally, any one of one or more operations can be repeated, combined, reorganized, skipped, or chained to provide a variety of additional and / or alternative methods. In the following discussion sections, reference can be made to the example environment 100, Figure 1 only as an example reference, Figures 2 to 8 the devices, components, embodiments or configurations, Figures 13 to 15 the devices or systems, and / or Figure 1 the entities detailed in other figures or the like. The technologies and devices described in this disclosure are not limited to being embodied in or performed by one entity or multiple entities operating on one device or those entities described with reference to the accompanying drawings.

[0085] Figure 9 Illustrated is an example method 900 for adaptive sounding reference signal mapping according to one or more aspects, including by an SRS port mapper (e.g.,Figure 1 The operations performed by the SRS port mapper 170). In some aspects, the operations of method 900 may be implemented by a user equipment to transmit an SRS symbol sequence that enables improved channel estimation through a base station.

[0086] At 902, a UE (e.g., UE 110) generates a set of SRS symbols including at least a first SRS symbol and a second SRS symbol. The UE may generate a set or sequence of four SRS symbols corresponding to respective antennas according to a four-antenna channel sounding configuration such as a 1T4R, 2T4R, or 4T=4R configuration.

[0087] At 904, the UE determines an offset of the second SRS symbol based on a difference between a first radio chain and a second radio chain of the UE. The SRS port mapper of the UE may determine the offset based on respective measurement or calibration information of the first radio chain and the second radio chain. In some cases, the first radio chain is a transmit-capable radio chain and the second radio chain is a receive-only radio chain. Alternatively or additionally, the SRS port mapper determines another offset based on a difference between a third radio chain and a fourth radio chain of the UE. Determining the offset may include determining an adjustment to the path gain (or other transmission parameter) of the first radio chain such that when the path gain of the first radio chain is adjusted, the first radio chain approximates the second radio chain.

[0088] At 906, the UE maps the first SRS symbol to an antenna port of the first radio chain of the UE. The SRS port mapper may map the first SRS symbol corresponding to the transmit-capable radio chain to a physical antenna port of the transmit-capable radio chain. At 908, the UE maps the second SRS symbol to an antenna port of the first radio chain of the UE. The SRS port mapper may map the second SRS symbol corresponding to the receive-only radio chain to a physical antenna port of the transmit-capable radio chain. In other words, the second SRS symbol may be mapped to a physical antenna of the transmit-capable radio chain, and the second SRS symbol may be scheduled for time and frequency resources of the air interface expected to be used by another radio chain.

[0089] At 910, the UE transmits a first SRS symbol via an antenna port of the UE's first radio chain. The UE may transmit the first SRS symbol via a first time and frequency resource associated with the first antenna of a four-antenna channel sounding procedure. At 912, the UE applies an offset to the second SRS symbol to the first radio chain. By doing so, the UE may compensate for or adapt the first radio chain to approximate another radio chain of the UE, such as a receive-only transmit chain. Applying the offset may include adjusting the path gain of the first radio chain. At 914, while applying the offset to the first radio chain, the UE transmits a second SRS symbol via the antenna port of the first radio chain. The UE may transmit the second SRS symbol via a second time and frequency resource associated with the second antenna of a four-antenna channel sounding procedure. In aspects, the UE may repeat one or more of operations 904 to 914 to transmit third and fourth SRS symbols corresponding to the third and fourth radio chains (e.g., receive-only) of the UE via a second transmit-capable radio chain (e.g., a UE configured with 2T2R). In other aspects, the UE may repeat one or more of operations 904 to 914 to transmit third and fourth SRS symbols corresponding to the third and fourth radio chains (e.g., receive-only) of the UE via a transmit-capable radio chain (e.g., a UE configured with 1T2R).

[0090] At 916, the UE communicates with the base station based on channel state information determined using at least the first and second SRS symbols. As described, the base station may determine more accurate channel state information based on SRS symbols that approximate an adaptive mapping of an additional communication channel. This channel state information may then be used to determine a communication configuration of the UE or the base station that enables higher throughput communication over the channel between the UE and the base station.

[0091] Figure 10 Illustrates an example method 1000 for mapping offset sounding reference signal symbols to respective antennas according to one or more aspects, including operations performed by an SRS port mapper (e.g., Figure 1 the SRS port mapper 170). In some aspects, the operations of method 1000 are performed by a user equipment (e.g., 2T2R) to transmit a sequence of four SRS symbols to a base station via respective antennas of two transmit chains.

[0092] At 1002, the UE (e.g., UE 110) transmits UE capability information to the base station (e.g., base station 120), the UE capability information indicating that the UE supports channel sounding using four antennas. For example, the UE may transmit a UE capability information element indicating that the UE is capable of 2T4R antenna switching.

[0093] At 1004, the UE generates a sequence of sounding reference signal (SRS) symbols corresponding to the four antennas of the UE. The UE may generate the sequence of the SRS signal according to a four-antenna channel sounding process. In some cases, the SRS symbols are allocated to SRS transmit ports corresponding to a 2T4R antenna switching configuration.

[0094] At 1006, the UE determines a first offset for a third SRS symbol among the SRS symbols based on the difference between the first antenna and the third antenna of the UE. At 1008, the UE determines a second offset for a fourth SRS symbol among the SRS symbols based on the difference between the second antenna and the fourth antenna of the UE. The UE may determine the first and second offsets based on the respective measurement information (e.g., radio link information) of the radio links of the first antenna and the third antenna, or the second antenna and the fourth antenna. In some cases, the first and second antennas are the primary transmit antenna and the secondary transmit antenna of the UE, and the third and fourth antennas are the receive-only antennas of the UE (e.g., MIMO receive antennas).

[0095] At 1010, the UE maps the first SRS symbol and the third SRS symbol among the SRS symbols to the first antenna. The SRS port mapper of the UE may map the third symbol or the SRS transmit port of the third symbol to the antenna port of the first antenna. At 1012, the UE maps the second SRS symbol and the fourth SRS symbol among the SRS symbols to the second antenna. The SRS port mapper of the UE may map the fourth symbol or the SRS transmit port of the fourth symbol to the antenna port of the second antenna. In other words, the SRS port mapper may map the SRS symbol sequence or the SRS transmit ports of the sequence to the first and second antenna ports of the UE.

[0096] At 1014, the UE transmits the first SRS symbol to the base station via the first radio link of the first antenna through the channel. At 1016, the UE transmits the second SRS symbol to the base station via the second radio link of the second antenna through the channel. The transmission of the first and second SRS symbols enables the base station to estimate the channel characteristics of the first and second communication paths through the channel.

[0097] At 1018, with a first offset applied to the first radio link, the UE transmits a third SRS symbol to the base station via a first antenna over a channel. At 1020, with a second offset applied to the second radio link, the UE transmits a fourth SRS symbol to the base station via a second antenna over a channel. By applying the respective offsets to the first and second radio links, the SRS port mapper can approximate the transmission of the third and fourth SRS symbols for the third and fourth radio links (e.g., receive-only radio links). Thus, the transmission of the third and fourth SRS symbols enables the base station to estimate the channel characteristics of the third and fourth communication paths over the channel. Accordingly, aspects of adaptive sounding reference signal mapping can enable the base station to more accurately estimate channel characteristics based on four communication paths over the channel (2T4R), rather than just two communication paths achieved with prior art using the UE's hardware configuration (1T2R).

[0098] Figure 11A and 11B illustrates an example method 1100 for enabling a user equipment to perform aspects of adaptive sounding reference signal mapping, including operations performed by an SRS port mapper (e.g., Figure 1 SRS port mapper 170). In some aspects, the operations of method 1100 are performed by the user equipment to characterize and pair corresponding antennas of radio links for adaptive sounding reference signal mapping.

[0099] At 1102, the UE (e.g., UE 110) characterizes radio links of a plurality of antennas of the UE to provide respective radio link information. For example, total isotropic sensitivity (TIS) can be performed on the plurality of antennas and corresponding radio links of the UE, and the measurement results are stored in the UE's memory or the UE's modem. The UE can also determine calibration information or receive metrics for the plurality of antennas and corresponding radio links to store as radio link information.

[0100] At 1104, the UE assigns receive antennas to transmit antennas based on the respective radio link information. Given that channel estimation may rely on the reciprocity of downlink and uplink communications (e.g., in a TDD network), if the performance characteristics between the radio links of the antennas differ too much, adaptive SRS symbol mapping to approximate additional receive-only radio links may not be beneficial. For example, when a receive-only radio link (e.g., the third or fourth radio link) has a gain of 5 dB or less relative to a transmit-capable radio link (e.g., the primary or secondary radio link) for a particular frequency band, channel estimation via 1T4R (or 2T4R) may perform worse than channel estimation via 1T2R (or 2T2R). Accordingly, aspects of adaptive SRS symbol mapping can characterize and pair a plurality of radio links of the UE to optimize SRS symbol mapping to corresponding SRS transmissions or physical antenna ports.

[0101] In the context of operation 1104, the UE can compare the respective radio link information of multiple radio links of the UE to determine the performance characteristic differences between radio link pairs (e.g., a transmit-capable radio link and a receive-only radio link). In some cases, the UE compares the performance characteristic differences (e.g., relative gain or receive sensitivity) with a threshold (e.g., 5 dB) to determine whether adaptive SRS mapping should be implemented. In response to the performance difference exceeding the threshold, the UE determines not to implement adaptive SRS mapping for the radio link pair. In response to the performance difference not exceeding the threshold, the UE determines to implement adaptive SRS mapping for the radio link pair. In some aspects, the UE can compare different radio link pairs (e.g., a transmit-capable radio link and a receive-only radio pair) to determine the performance differences of multiple pairs. Then, in the case of the smallest performance difference, the UE can assign the receive antenna radio link to the transmit antenna radio link (or pair the receive antenna radio link and the transmit antenna radio link). In other words, the UE can assign or pair the radio links with the most closely matched performance together.

[0102] At 1106, the UE determines the offset between the radio link of the receive antenna and the radio link of the transmit antenna for the radio link of the receive antenna. Based on the assignment or pairing of the radio links, the UE can determine the offset between the radio link of the receive antenna and the radio link of the transmit antenna. In some cases, the UE determines the offset by accessing the radio link information indicating the respective receive performance or calibration metric of the radio link. The UE can also use the information related to the performance differences between the radio links determined in operation 1104. Optionally, at 1108, the UE stores the offset of the radio link pair of the receive antenna in the memory of the UE or in the memory of the modem coupled to the radio link.

[0103] At 1110, the UE generates a set of SRS symbols for the channel sounding process. The UE can generate the set of SRS symbols for channel sounding according to a 1T4R, 2T4R, or 4T = 4R antenna switching configuration. From operation 1110, method 1100 proceeds from Figure 11A to Figure 11B operation 1112, as shown at 1150.

[0104] At 1112, the UE maps the first SRS symbol corresponding to the transmit antenna in the set of SRS symbols to the radio chain of the transmit antenna. The UE may map the first SRS symbol corresponding to the transmit antenna to a transmit-capable radio chain or a physical antenna port of a transmit-capable radio chain. At 1114, the UE maps the second SRS symbol corresponding to the receive antenna in the set of SRS symbols to the radio chain of the transmit antenna. The UE may map the second SRS symbol corresponding to the receive antenna to a transmit-capable radio chain or a physical antenna port of a transmit-capable radio chain. In other words, the second SRS symbol may be mapped to a physical antenna of a transmit-capable radio chain, and the second SRS symbol may be scheduled for the time and frequency resources of the air interface expected to be used by another radio chain in a 1T4R, 2T2R, or 4T4R antenna switching configuration.

[0105] At 1116, as part of a channel sounding process, the UE transmits the first SRS symbol to the base station via the radio chain of the transmit antenna. The UE may transmit the first SRS symbol via the first time and frequency resources associated with the first antenna of a four-antenna channel sounding process. At 1118, the UE applies an offset of the receive chain of the receive antenna to the radio chain of the transmit antenna. By doing so, the UE may compensate or adapt the transmit-capable radio chain to approximate another radio chain of the UE, such as a receive-only transmit chain of the receive antenna.

[0106] At 1120, as part of a channel sounding process, the UE transmits the second SRS symbol to the base station via the radio chain of the transmit antenna. When applying the offset to the radio chain, the second SRS symbol is transmitted using the radio chain of the transmit antenna. The UE may transmit the second SRS symbol via the second time and frequency resources associated with the second antenna of a four-antenna channel sounding process. In various aspects, the UE may repeat one or more of operations 1112 to 1120 to transmit third and fourth SRS symbols corresponding to the third and fourth radio chains (e.g., receive-only) of the UE via a second transmit-capable radio chain (e.g., a UE configured with 2T2R). In other aspects, the UE may repeat one or more of operations 1112 to 1120 to transmit third and fourth SRS symbols corresponding to the third and fourth radio chains (e.g., receive-only) of the UE via a transmit-capable radio chain (e.g., a UE configured with 1T2R) to approximate a 1T4R sounding process.

[0107] As described, the base station may determine more accurate channel state information based on SRS symbols that approximate an adaptive mapping of an additional communication channel. This channel state information may then be used to determine a communication configuration of the UE or the base station that enables higher throughput communication over the channel between the UE and the base station. By way of example, consider Figure 12, where example figure 1200 illustrates the improved throughput performance of a user equipment provided by adaptive sounding reference signal mapping according to the described aspects. Generally, a UE uses a sounding channel to transmit SRS symbols for downlink channel estimation, rank selection, and beamforming management. By implementing aspects of adaptive sounding reference signal mapping, the UE can improve downlink throughput as well as network coverage. As Figure 12 shown, for a typical 1T2R hardware configuration 1202, the UE can implement aspects of adaptive sounding reference signal mapping to approximate a 1T4R antenna configuration 1204 to achieve a higher downlink throughput of 15% (15% at 1206) in NR band 77. Here, it should be noted that with radio link performance varying up to 6 dB (e.g., 1T4R (0 -3-3 -6)), the UE can still achieve increased throughput on a hardware-constrained (e.g., 1T2R (0-3)) configuration.

[0108] Example apparatus and system

[0109] Figures 13 to 15 Figures illustrate examples of an apparatus, a system-on-chip, and a wireless communication processor that can implement aspects of adaptive sounding reference signal mapping for improved channel estimation. These entities can implement, individually or in combination, one or more aspects of the adaptive sounding reference signal mapping described previously Figures 1 to 12 in the description. The apparatus, system-on-chip, or wireless communication processor can be implemented with any suitable combination of components or elements and can include other components shown or described in any of the others Figures 1 to 12 illustrated or described.

[0110] Figure 13 Figures illustrate the various components of an example electronic device 1300 that can implement adaptive sounding reference signal mapping according to one or more aspects described herein. The electronic device 1300 can be implemented as any form of consumer device, computing device, portable device, user device, user equipment, server, communication device, mobile phone, navigation device, gaming device, media device, messaging device, media player, and / or other type of electronic device or wireless-enabled device as any one or combination of a fixed or mobile device. For example, the electronic device 1300 can be implemented as a smart phone, a phablet (tablet phone), a laptop computer, a set-top box, a wireless drone, computing glasses, a wearable computer, a vehicle-based computing system, or a wireless broadband router.

[0111] The electronic device 1300 includes a communication transceiver 1302 that enables wired and / or wireless communication of device data 1304, such as transmitted data, received data, or other information as described herein. Example communication transceivers 1302 include NFC transceivers, WPAN radios compliant with various IEEE 802.15 standards, WLAN radios compliant with any of the various IEEE 802.11 standards, WWAN (compliant with 3GPP) radios, LTE transceivers, 5G NR transceivers, 6G transceivers, wireless metropolitan area network (WMAN) radios compliant with various IEEE 802.16 standards, and wired local area network (LAN) Ethernet transceivers. In some aspects, multiple communication transceivers 1302 or their components are operatively coupled to corresponding examples of radio chains 304 embodied on the electronic device 1300. The radio chain 304 can be implemented similar to radio chains 0 304-0 to radio chains 3 304-3 (e.g., transceiver chains or receive-only chains) as described with reference to Figures 1 to 12 Here, the radio chain 30x can include at least four radio chains that the SRS port mapper 170 can use to implement various aspects of adaptive sounding reference signal mapping to improve channel estimation.

[0112] The electronic device 1300 may also include one or more data input / output ports 1306 (data I / O ports 1306) through which any type of data, media content, and / or other input can be received, such as user-selectable input, messages, applications, music, television content, recorded video content, and any other type of audio, video, and / or image data received from any content and / or data source. The data I / O ports 1306 can include USB ports, coaxial cable ports, and other serial or parallel connectors (including internal connectors) for flash memory, DVDs, CDs, etc. These data I / O ports 1306 can be used to couple the electronic device to components, peripherals, or accessories such as keyboards, microphones, or cameras.

[0113] The electronic device 1300 of this example includes at least one processor 1308 (e.g., one or more application processors, processor core microprocessors, digital signal processors (DSPs), controllers, etc.), and the processor may include a combined processor and memory system that executes computer-executable instructions stored on a computer-readable medium to control operations or implement the functions of the device. Generally, the processor or processing system may be implemented at least partially in hardware, and the hardware may include components of an integrated circuit or system-on-chip, DSP, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), complex programmable logic device (CPLD), and other implementations in silicon and / or other hardware.

[0114] Alternatively or additionally, the electronic device 1300 may be implemented by any one or combination of the electronic circuitry systems 1310, and the electronic circuitry systems may include hardware, fixed logic circuitry, or physical interconnections (e.g., traces or connectors) implemented in combination with processing and control circuitry. This electronic circuitry system 1310 may implement executable or hardware-based modules (not shown) through logic circuitry systems and / or hardware such as FPGAs or CPLDs. Although not shown, the electronic device 1300 may also include a system bus, an interconnect structure, a crossbar switch, or a data transfer system that couples various components within the device. The system bus or interconnect structure may include any one or combination of different bus structures or IP blocks, such as a memory bus, a memory controller, a peripheral bus, a universal serial bus, an interconnect node, and / or a processor or local bus that utilizes any one of various bus architectures.

[0115] The electronic device 1300 also includes one or more memory devices 1312 that implement data storage, and examples of the memory devices include RAM, SRAM, DRAM, NVRAM, ROM, flash memory, EPROM, EEPROM, and disk storage devices. Any or all of the memory devices 1312 may implement persistent and / or non-transitory storage of information, data, or code, and thus do not include transient signals or carriers in the general context of this disclosure. For example, the memory device 1312 provides a data storage mechanism to store device data 1304 and other types of data (e.g., user data). The memory device 1312 may also store the operating system 1314, firmware, and / or device applications 1316 of the electronic device as instructions, code, or information. These instructions or code may be executed by the processor 1308 to implement various functions of the electronic device, so as to provide a user interface, enable data access, or manage connectivity to a wireless network.

[0116] In this example, the memory device 1312 also stores processor-executable code or instructions for providing an example of the SRS port mapper 170, which may be similar to or different from the SRS port mapper described in reference Figures 1 to 12 Figures 1 to 12 . The memory device also includes instance radio link information 172, with which the SRS port mapper 170 may interact to implement aspects of the adaptive sounding reference signal mapping as described herein. For example, the SRS port mapper 170 may characterize the respective reception metrics of multiple radio links, store the respective reception metrics as part of the radio link information 172, and determine radio link offsets based on the radio link information 172. As part of the channel sounding process, the SRS port mapper 170 may map multiple SRS symbols to one physical antenna port and, during the transmission of at least one of the multiple SRS symbols, apply an offset to the transmit chain to implement aspects of the adaptive sounding reference signal mapping for improving channel estimation. The SRS port mapper 170 of the electronic device 1300 may implement these and any other aspects of the adaptive sounding reference signal mapping as described herein.

[0117] As Figure 13 shown, the electronic device 1300 may include an audio and / or video processing system 1318 for processing audio data and / or delivering audio and video data to an audio system 1320 and / or a display system 1322 (e.g., a video buffer or a device screen). The audio system 1320 and / or the display system 1322 may include any device for processing, displaying, and / or otherwise rendering audio, video, graphics, and / or image data. Display data and audio signals may be transmitted to the audio component and / or the display component via an RF link, a super video link, an HDMI (High-Definition Multimedia Interface), a DisplayPort, a composite video link, a component video link, a DVI (Digital Video Interface), an analog audio connection, or other similar communication links such as the media data port 1324. In some embodiments, the audio system 1320 and / or the display system 1322 are external or separate components of the electronic device 1300. Alternatively, the display system 1322 may be an integrated component of the exemplary electronic device 1300, such as part of an integrated display with a touch interface.

[0118] The electronic device 1300 further includes antennas 1326-1, 1326-2 to 1326-n, where n can be any suitable number of antennas. The antennas 1326-1 to 1326-n are coupled to the radio chain 30x of the electronic device 1300 via an RF front end (not shown), and the radio chain may include any suitable combination of components to facilitate the communication transceiver 1302 of the antennas 1326-1 to 1326-n to transmit or receive signals. In some aspects, each of the antennas 1326-1 to 1326-n corresponds to a respective radio chain 304 or antenna port 310 (not shown) of the electronic device. Generally, the SRS port mapper 170 can interact with any one of the radio chain information 172, the communication transceiver 1302, the radio chain 304, the antenna port 310, and / or the antennas 1326-1 to 1326-n to implement the adaptive sounding reference signal mapping for improving channel estimation as described herein. Alternatively or additionally, the electronic device 1300 can represent an example implementation of the user equipment 110 as described throughout this disclosure. Thus, in some cases, the processor 1308 is an example of the processor 208 (not shown), and / or the memory device 1312 is an example of the computer-readable storage medium 210 (not shown) for storing various data, instructions, or codes for implementing the SRS port mapper, the radio chain information, or other applications. Thus, the aspects of the adaptive sounding reference signal mapping for improving channel estimation as described herein can be implemented by or in combination with Figure 13 the electronic device 1300.

[0119] Figure 14 FIG. illustrates an example system-on-a-chip (SoC) that can implement aspects of the adaptive sounding reference signal mapping for improving channel estimation. The SoC 1400 can be embodied as or in any type of user equipment 110, user device, device, other device, or system as described with reference to Figures 1 to 13 or Figure 15 to implement the adaptive sounding reference signal mapping for improving channel estimation. Although described with reference to a chip-based package, the components shown in Figure 14 can also be embodied as other system or component configurations, such as but not limited to field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), digital signal processors (DSPs), complex programmable logic devices (CPLDs), system-in-packages (SiPs), package-on-packages (PoPs), processing and communication chip sets, communication coprocessors, sensor coprocessors, etc.

[0120] In this example, the SoC 1400 includes a communication transceiver 1402 and a wireless modem 1404 that enable wired or wireless communication of system data 1406 (e.g., received data, data being received, data scheduled for transmission, packetized data, etc.). In some aspects, the wireless modem 1404 is a multi-mode multi-band modem or baseband processor that can be configured to communicate according to various communication protocols and / or in different frequency bands, such as those described throughout this disclosure (e.g., LTE, 5G NR, or 6G) or frequency bands. The wireless modem 1404 may include a transceiver interface (not shown) for communicating encoded or modulated signals with transceiver circuitry that includes transmitter chain and receiver chain circuitry (e.g., radio chains 0 304-0 to radio chains 3 304-3 of the UE 110). The wireless modem 1404 may also include an example of an SRS port mapper 170 and radio chain information 172 shown in Figure 14 or associated with the example.

[0121] System data 1406 or other system content may include configuration settings of the system or various components, media content stored by the system, and / or information associated with a user of the system. Media content stored on the system-on-chip 1400 may include any type of audio, video, and / or image data. The system-on-chip 1400 also includes one or more data inputs 1408 through which any type of data, media content, and / or input can be received, such as user input, user-selectable input (explicit or implicit), or any other type of audio, video, and / or image data received from content and / or data sources. Alternatively or additionally, the data input 1408 may include various data interfaces that can be implemented as any one or more of a serial and / or parallel interface, a wireless interface, a network interface, and any other type of communication interface implemented to enable communication with other devices or systems.

[0122] The system-on-chip 1400 includes one or more processor cores 1410 that process various computer-executable instructions to control the operation of the system-on-chip 1400 and implement techniques for improved channel estimation with adaptive sounding reference signal mapping. Alternatively or additionally, the system-on-chip 1400 may be implemented with any one or combination of hardware, firmware, or fixed logic circuitry implemented in conjunction with processing and control circuitry generally shown at 1412. Although not shown, the system-on-chip 1400 may also include a bus, interconnect, crossbar, or fabric that couples the various components within the system.

[0123] The system-on-chip 1400 also includes a memory 1414 (e.g., a computer-readable medium), such as one or more memory circuits that implement persistent and / or non-transitory data storage and thus do not include transient signals or carriers. Examples of the memory 1414 include RAM, SRAM, DRAM, NVRAM, ROM, EPROM, EEPROM, or flash memory. The memory 1414 provides data storage for system data 1406 as well as firmware 1416, applications 1418, and any other type of information and / or data related to the operational aspects of the system-on-chip 1400. For example, the firmware 1416 can be held in the memory 1414 as processor-executable instructions of an operating system (e.g., a real-time OS) and executed on one or more processor cores 1410.

[0124] The applications 1418 can include system managers, such as any form of control applications, software applications, signal processing and control modules, system-specific native code, abstract modules, or gesture modules, etc. The memory 1414 can also store system components or utilities for implementing aspects of an adaptive sounding reference signal mapping for improving channel estimation, such as an SRS port mapper 170 and radio chain information 172. These entities can be embodied as combined or separate components, examples of which are referenced as the corresponding entities or functional descriptions illustrated in Figures 1 to 13 or Figure 15 As shown. In some aspects, the SRS port mapper 170 interacts with the radio chain information 172 and the wireless modem 1404 to implement aspects of the adaptive sounding reference signal mapping. For example, the SRS port mapper 170 can map multiple SRS symbols to the same physical antenna port and apply an offset to the transmit chain of the antenna port when transmitting at least some of the SRS symbols to approximate channel sounding through other antennas of the device or apparatus. By doing so, the SRS port mapper 170 can achieve improved channel estimation and increase the throughput of downlink or uplink communication. Although shown in the memory 1414, one or more elements of the SRS port mapper 170 can be implemented in whole or in part by hardware or firmware.

[0125] In some aspects, the system-on-chip 1400 also includes additional processors or coprocessors to enable other functions, such as a graphics processor 1420, an audio processor 1422, and an image sensor processor 1424. The graphics processor 1420 can render graphics content associated with the user interface, operating system, or applications of the system-on-chip 1400. In some cases, the audio processor 1422 encodes or decodes audio data and signals, such as audio signals and information associated with a voice call, or encoded audio data for playback. The image sensor processor 1424 can be coupled to an image sensor and provide image data processing, video capture, and other visual media conditioning and processing functions.

[0126] The system-on-chip 1400 can also include a security processor 1426 to support various security, encryption, and cryptographic operations to provide secure communication protocols and encrypted data storage. Although not shown, the security processor 1426 can include one or more cryptographic engines, cryptographic libraries, hash modules, or random number generators to support encryption and cryptographic processing of information or communication of the system-on-chip 1400. Alternatively or additionally, the system-on-chip 1400 can include a positioning and location engine 1428 and a sensor interface 1430. Generally, the positioning and location engine 1428 can provide positioning or location data by processing signals of a global navigation satellite system (GNSS) and / or other motion or inertial sensor data (e.g., dead reckoning navigation). The sensor interface 1430 enables the system-on-chip 1400 to receive data from various sensors such as capacitance and motion sensors. In some aspects, the SRS port mapper 170 can interact with any one of the processors or coprocessors of the system-on-chip 1400 to implement an adaptive sounding reference signal mapping for improving channel estimation.

[0127] Figure 15 FIG. illustrates an example configuration of a wireless communication processor 1500 (communication processor 1500) that can implement various aspects of an adaptive sounding reference signal mapping for improving channel estimation. Although commonly referred to as a communication processor, the communication processor 1500 can be implemented as a modem baseband processor, a software-defined radio module, a configurable modem (e.g., a multi-mode, multi-band modem), a wireless data interface, or a wireless modem, such as the wireless modem 1404 of the system-on-chip 1400. The wireless communication processor 1500 can be implemented in a device or system to support data access, messaging, or data-based services of a wireless network, as well as various audio-based communications (e.g., voice calls).

[0128] In this example, the wireless communication processor 1500 includes at least one processor core 1502 and a memory 1504, which is implemented as a hardware-based memory that provides persistent and / or non-transitory data storage and thus does not include transient signals or carriers. The processor core 1502 can be configured as any suitable type of processor core, microcontroller, digital signal processor core, etc. The memory 1504 can include any suitable type of memory device or circuit, such as RAM, DRAM, SRAM, NVRAM, ROM, flash memory, etc. Generally, the memory stores data 1506 of the communication processor 1500, as well as firmware 1508 and other applications. The processor core 1502 can execute processor-executable instructions of the firmware 1508 or applications to implement functions of the communication processor 1500, such as signal processing and data encoding operations. The memory 1504 can also store data and information that can be used to implement aspects of an adaptive sounding reference signal mapping for improving channel estimation. In some aspects, the memory 1504 of the communication processor 1500 includes radio link information 172, modem and transceiver configuration information, or other information (not shown) that can be used to implement the adaptive sounding reference signal mapping.

[0129] The communication processor 1500 may also include electronic circuitry 1510 for managing or coordinating the operation of various components and an audio codec 1512 for processing audio signals and associated data. The electronic circuitry 1510 can include hardware, fixed logic circuitry, or physical interconnections (e.g., traces or connectors) that, in combination with the processing and control circuitry of the communication processor and various components, are implemented. The audio codec 1512 can include a combination of logic, circuitry, or firmware (e.g., algorithms) to support the encoding and / or decoding of audio information and audio signals, such as analog signals and digital data associated with the voice or sound functions of the communication processor 1500.

[0130] The system interface 1514 of the communication processor 1500 enables communication with a host system or an application processor. For example, the communication processor 1500 can provide or expose data access functions to the system or application processor through the system interface 1514. In this example, the communication processor also includes a transceiver circuit interface 1516 and an RF circuit interface 1518 through which the communication processor 1500 can manage or control the corresponding functions of a transceiver circuit (e.g., transmit and receive chain circuitry) or an RF front end to implement various communication protocols and technologies. In various aspects, the communication processor includes digital signal processing or signal processing blocks for encoding and modulating transmitted data or demodulating and decoding received data.

[0131] In this example, the communication processor 1500 includes an encoder 1520, a modulator 1522, and a digital-to-analog converter 1524 (D / A converter 1524) for encoding, modulating, and converting data transmitted to the transceiver circuit interface. The communication processor also includes an analog-to-digital converter 1526 (A / D converter 1526), a demodulator 1528, and a decoder 1530 for converting, demodulating, and decoding data received from the transceiver circuit interface 1516. In some aspects, these signal processing blocks and components are implemented as part of the respective transmit and receive paths (e.g., radio chains 304-0 to 304-3) of the communication processor 1500, and they can be configured for different radio access technologies or frequency bands.

[0132] The wireless communication processor 1500 also includes an SRS port mapper 170, which can be embodied alone or in combination with other components, and examples of the SRS port mapper are referenced Figures 1 to 14 in the corresponding entity or functional description illustrated therein. In various aspects, the SRS port mapper 170 interacts with the radio chain information 172 and other components of the wireless communication processor 1500 to implement an adaptive sounding reference signal mapping for improving channel estimation. For example, the SRS port mapper 170 can characterize the respective received metrics of multiple radio chains, store the respective received metrics as part of the radio chain information 172, and determine a radio chain offset based on the radio chain information 172. As part of the channel sounding process, the SRS port mapper 170 can map multiple SRS symbols to a physical antenna port and apply an offset to the transmit chain during the transmission of at least one of the multiple SRS symbols according to one or more aspects of the adaptive sounding reference signal mapping for improving channel estimation. Based on the improved channel estimation, the wireless communication processor 1500 can transmit uplink or downlink data with increased throughput. Alternatively or additionally, the SRS port mapper 170 can cause or direct the wireless communication processor 1500 to implement any aspect of the adaptive sounding reference signal mapping described with reference to Figures 1 to 14 therein.

[0133] In addition to the above description, controls can also be provided to the user to allow the user to select whether and when the devices, systems, applications, and / or features described herein can enable the collection of user information, such as one or more of wireless link metrics (radio link metrics), connection duration information, average connection length, signal quality / intensity information, network identification information, network basic service set identifier (BSSID) information, mobile network subscriber information, most recently used wireless communication band / channel, user preferences, the user's current location (if the user has transmitted content or information to the server), etc.

[0134] Additionally, certain data can be processed in one or more ways before storage or use to remove personally identifiable information. For example, a user's identity can be processed such that personally identifiable information cannot be determined for the user. For example, the user's geographical location where location information is obtained (e.g., to a city, postal code, or state / province level) can be generalized or randomized such that the user's specific location cannot be determined. Thus, the user can control what information about the user is collected, one or more of the user's devices, how the information is used, and / or what information is provided to the user.

[0135] Variant

[0136] Although the above devices and techniques are described in the context of an adaptive sounding reference signal mapping for improving channel estimation in a wireless network where a user equipment can access one or more base stations, the described user equipment, devices, systems, and methods are non - restrictive and can be applied to other contexts, user equipment deployments, or wireless communication environments.

[0137] In general, the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Some operations of example methods can be described in the general context of executable instructions stored on a computer - readable storage memory local and / or remote to a computer - processing system, and implementations can include software applications, programs, functions, etc. Alternatively or additionally, any of the functions described herein can be performed at least in part by one or more hardware logic components, such as but not limited to FPGA, ASIC, ASSP, SoC, CPLD, coprocessor, context hub, sensor coprocessor, etc.

[0138] A first method performed by a user equipment (UE) to implement an adaptive sounding reference signal mapping includes: generating a set of sounding reference signal (SRS) symbols, the set of SRS symbols including at least a first SRS symbol and a second SRS symbol; for the second SRS symbol, determining an offset based on a difference between a first radio link of the UE and a second radio link of the UE; mapping the first SRS symbol to an antenna port of the first radio link; mapping the second SRS symbol to the antenna port of the first radio link; transmitting the first SRS symbol to a base station via the antenna port of the first radio link; applying the offset of the second SRS symbol to the first radio link; in the case of applying the offset to the first radio link, transmitting the second SRS symbol to the base station via the antenna port of the first radio link; and communicating with the base station based on channel state information determined using at least the first SRS symbol and the second SRS symbol.

[0139] In addition to the first method described above, a second method performed by a user equipment to implement adaptive sounding reference signal mapping includes: generating a sequence of sounding reference signal (SRS) symbols corresponding to four respective antennas of a plurality of radio chains, the four respective antennas including at least a first antenna, a second antenna, a third antenna, and a fourth antenna; for a third SRS symbol among the SRS symbols, determining a first offset based on a difference between a first radio chain of the first antenna and a third radio chain of the third antenna; for a fourth SRS symbol among the SRS symbols, determining a second offset based on a difference between a second radio chain of the second antenna and a fourth radio chain of the fourth antenna; mapping a first SRS symbol and the third SRS symbol among the SRS symbols to the first radio chain of the first antenna; mapping a second SRS symbol and the fourth SRS symbol among the SRS symbols to the second radio chain of the second antenna; transmitting the first SRS symbol to a base station via the first antenna of the first radio chain; transmitting the second SRS symbol to the base station via the second antenna of the second radio chain; applying the first offset to the first radio chain of the first antenna; applying the second offset to the second radio chain of the second antenna; when applying the first offset to the first radio chain, transmitting the third SRS symbol to the base station via the first antenna of the first radio chain; and when applying the second offset, transmitting the fourth SRS symbol to the base station via the second antenna of the second radio chain.

[0140] In addition to the above method, a third method performed by a user equipment to enable the user equipment to perform adaptive sounding reference signal mapping includes: characterizing radio chains of a plurality of antennas of the user equipment (UE) to provide respective radio chain information; allocating antennas of only receiving radio chains to antennas of capable of transmitting radio chains based on the respective radio chain information; determining an offset between the only receiving radio chains and the capable of transmitting radio chains based on the respective radio chain information; and storing the offset information in a memory of the UE to enable mapping of sounding reference signal symbols from antennas of the only receiving radio chains to antennas of the capable of transmitting radio chains.

[0141] In addition to any one of the above methods, an antenna port is a first antenna port of a first antenna of the UE, and the method further includes transmitting an indication to the base station that the UE is capable of performing a channel sounding process, the channel sounding process including transmitting a first SRS symbol via the first antenna; and transmitting a second SRS symbol via a second antenna of the UE, the second antenna being coupled to a second antenna port of a second radio chain.

[0142] In addition to any one of the methods described above or below, receiving a request from the base station to perform a channel sounding process by: transmitting a first SRS symbol via a first antenna of the UE; and transmitting a second SRS symbol via a second antenna of the UE.

[0143] In addition to any one of the methods described above or below, a request to perform a channel sounding procedure requests the UE to perform the channel sounding procedure by using one of the following: one transmit chain to four receive chains (1T4R) antenna switching; two transmit chains to four receive chains (2T4R) antenna switching; and the UE's hardware configuration is not capable of implementing the 1T4R or 2T4R channel sounding procedure.

[0144] In addition to any one of the methods described above or below, a first radio chain is configured to transmit uplink communications and receive downlink channels; and a second radio chain is configured to receive downlink communications.

[0145] In addition to any one of the methods described above or below, wherein the second radio chain is configured to only receive downlink communications and is not capable of transmitting uplink communications.

[0146] In addition to any one of the methods described above or below, the set of SRS symbols further includes a third SRS symbol and a fourth SRS symbol, the offset is a first offset, the antenna port of the first radio chain is a first antenna port, and the method further includes determining a second offset of the fourth SRS symbol based on the difference between the third radio chain and the fourth radio chain of the UE; mapping the third SRS symbol to the second antenna port of the third radio chain of the UE; mapping the fourth SRS symbol to the second antenna port of the third radio chain; transmitting the third SRS symbol to the base station via the second antenna port of the third radio chain; applying the second offset of the fourth SRS symbol to the third radio chain; transmitting the fourth SRS symbol to the base station via the second antenna port of the third radio chain, wherein the second offset is applied; and communicating with the base station based on the channel state information determined using at least the first SRS symbol, the second SRS symbol, the third SRS symbol, and the fourth SRS symbol.

[0147] In addition to any one of the methods described above or below, the mapping of the second SRS symbol to the antenna port of the first radio chain includes mapping the second SRS symbol to a physical antenna port associated with the first radio chain.

[0148] In addition to any one of the methods described above or below, the mapping of the second SRS symbol to the first radio chain includes mapping the second SRS symbol to a time resource or a frequency resource associated with the antenna or antenna port of the second radio chain in the resource grid of the air interface; or mapping the second SRS symbol from the first SRS port or the second SRS port to the antenna port of the first radio chain.

[0149] In addition to any of the methods described above or below, the offset is based on a difference in reception performance between a first radio link and a second radio link of the UE, or the offset is determined as a transmitter gain adjustment of the first radio link such that the performance of the first radio link approximates the performance of the second radio link.

[0150] In addition to any of the methods described above or below, determining the offset further includes determining the offset by: measuring a first reception performance metric of a first radio link of the UE; measuring a second reception performance metric of a second radio link of the UE; and determining a difference between the first reception performance metric and the second reception performance metric.

[0151] In addition to any of the methods described above or below, receiving an uplink configuration determined by the base station from channel state information from the base station, and wherein the communication further includes transmitting uplink communication to the base station according to the uplink configuration.

[0152] In addition to any of the methods described above or below, the communication further includes receiving downlink communication transmitted by the base station from the base station based on a downlink configuration determined by the base station from channel state information.

[0153] A user equipment includes at least one wireless transceiver; at least two radio links coupled to respective antennas; a processor; and a computer-readable storage medium including instructions that, in response to execution by the processor, are for instructing the user equipment to perform any of the above methods.

[0154] A system-on-chip includes a transceiver module that includes a transmitter module and a receiver module; an interface for at least a first radio link that is capable of performing transmit and receive operations; an interface for at least a second radio link that is capable of performing receive operations; a memory that stores radio link offset information; a processor core that is configured to execute processor-executable instructions; and a computer-readable storage medium including instructions that, in response to execution by the processor core, instruct a device embodying the system-on-chip to perform any of the above methods.

[0155] A computer-readable storage medium includes instructions that, in response to execution by a processor, cause any of the above methods to be performed.

[0156] Although aspects of an adaptive sounding reference signal mapping for improving channel estimation have been described in language specific to certain features, components, and / or methods, the subject matter of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as example implementations for managing modem and radio chain configurations, and other equivalent features and methods are contemplated within the scope of the appended claims. In addition, various different aspects are described, and it is understood that each described aspect may be implemented independently or in combination with other described aspects.

Claims

1. A method for performing sounding reference signal mapping by a user equipment UE to improve channel estimation, the method comprising: Generating a set of sounding reference signal SRS symbols including at least a first SRS symbol and a second SRS symbol; Determining an offset for the second SRS symbol based on a difference between a first radio chain of the UE and a second radio chain of the UE, wherein the first radio chain is transmit-capable and the second radio chain is receive-only; Mapping the first SRS symbol to an antenna port of the first radio chain; Mapping the second SRS symbol to the antenna port of the first radio chain; Transmitting the first SRS symbol to a base station via the antenna port of the first radio chain; Applying the offset of the second SRS symbol to the first radio chain to make the first radio chain approximate the performance of the second radio chain; Transmitting the second SRS symbol to the base station via the antenna port of the first radio chain when the offset is applied to the first radio chain; and Communicating with the base station based on channel state information determined at least using the first SRS symbol and the second SRS symbol.

2. The method according to claim 1, wherein, The antenna port is a first antenna port coupled to a first antenna of the UE, and the method further comprises: Transmitting an indication to the base station that the UE is capable of performing a channel sounding process, the channel sounding process comprising: Transmitting the first SRS symbol via the first antenna; and Transmitting the second SRS symbol via a second antenna of the UE, the second antenna being coupled to a second antenna port of the second radio chain.

3. The method according to claim 2, further comprising: Receiving from the base station a request for performing the channel sounding process by: Transmitting the first SRS symbol via the first antenna of the UE; And Transmitting the second SRS symbol via the second antenna of the UE.

4. The method according to claim 3, wherein The hardware configuration of the UE is not capable of performing a 1T4R or 2T4R channel sounding process, and the request for performing the channel sounding process is a request for the UE to perform the channel sounding process by using one of the following: One transmit chain to four receive chains 1T4R antenna switching; or Two transmit chains to four receive chains 2T4R antenna switching.

5. The method according to claim 1, wherein: The first radio chain is configured to transmit uplink communications and receive downlink communications; and The second radio chain is configured to receive downlink communications.

6. The method according to claim 1, wherein The second radio chain is configured to only receive downlink communications and is not capable of transmitting uplink communications.

7. The method according to claim 1, wherein: The set of SRS symbols further includes a third SRS symbol and a fourth SRS symbol, the offset is a first offset, the antenna port of the first radio chain is a first antenna port, and the method further comprises: Determine a second offset for the fourth SRS symbol based on a difference between a third radio link and a fourth radio link of the UE; Map the third SRS symbol to a second antenna port of the third radio link of the UE; Map the fourth SRS symbol to the second antenna port of the third radio link; Transmit the third SRS symbol to the base station via the second antenna port of the third radio link; Apply the second offset of the fourth SRS symbol to the third radio link; Transmit the fourth SRS symbol to the base station via the second antenna port of the third radio link with the second offset applied; and Communicate with the base station based on channel state information determined at least using the first SRS symbol, the second SRS symbol, the third SRS symbol, and the fourth SRS symbol.

8. The method according to claim 1, wherein, Mapping the second SRS symbol to the antenna port of the first radio link includes: mapping the second SRS symbol to a physical antenna port associated with the first radio link.

9. The method according to claim 1, wherein Mapping the second SRS symbol to the first radio link includes: Mapping the second SRS symbol to a time resource or a frequency resource of a resource grid of an air interface associated with an antenna or an antenna port of the second radio link; or Mapping the second SRS symbol from a first SRS port or a second SRS port to the antenna port of the first radio link.

10. The method according to claim 1, wherein: The offset is determined as a transmitter gain adjustment of the first radio link such that the performance of the first radio link approximates the performance of the second radio link.

11. The method according to claim 1, wherein, The offset is determined by: Measuring a first reception performance metric of the first radio link of the UE; Measuring a second reception performance metric of the second radio link of the UE; And Determining a difference between the first reception performance metric and the second reception performance metric.

12. The method according to claim 1, further comprising: Receiving, from the base station, an uplink configuration determined by the base station from the channel state information, and wherein the communication further comprises: Transmitting uplink communication to the base station according to the uplink configuration.

13. The method according to any one of claims 1 to 12, wherein, The communication further comprises: Receiving downlink communication transmitted by the base station from the base station based on a downlink configuration determined by the base station from the channel state information.

14. A method for implementing adaptive sounding reference signal mapping using multiple radio links of a user equipment, the method comprising: Generating a sequence of sounding reference signal SRS symbols corresponding to four respective antennas of the multiple radio links, the sequence of SRS symbols including a first SRS symbol, a second SRS symbol, a third SRS symbol, and a fourth SRS symbol, and the four respective antennas including at least a first antenna, a second antenna, a third antenna, and a fourth antenna; Determine a first offset for the third SRS symbol based on the difference between the first radio link of the first antenna and the third radio link of the third antenna, wherein the first radio link is transmissive and the third radio link is receive-only; Determine a second offset for the fourth SRS symbol based on the difference between the second radio link of the second antenna and the fourth radio link of the fourth antenna, wherein the second radio link is transmissive and the fourth radio link is receive-only; Map the first SRS symbol and the third SRS symbol to the first radio link of the first antenna; Map the second SRS symbol and the fourth SRS symbol to the second radio link of the second antenna; Transmit the first SRS symbol to a base station via the first antenna of the first radio link; Transmit the second SRS symbol to the base station via the second antenna of the second radio link; Apply the first offset to the first radio link of the first antenna so that the performance of the first radio link approximates that of the third radio link; Apply the second offset to the second radio link of the second antenna so that the performance of the second radio link approximates that of the fourth radio link; When applying the first offset to the first radio link, transmit the third SRS symbol to the base station via the first antenna of the first radio link; and When applying the second offset, transmit the fourth SRS symbol to the base station via the second antenna of the second radio link.

15. A method for enabling a user equipment to perform adaptive sounding reference signal mapping, the method comprising: Characterize radio links of a plurality of antennas of the user equipment to provide corresponding radio link information; Based on the corresponding radio link information, assign antennas with receive-only radio links to antennas with transmissive radio links; Based on the corresponding radio link information, determine an offset between the receive-only radio link and the transmissive radio link; And Store the offset in a memory of the user equipment to enable mapping of sounding reference signal symbols from the antennas with the receive-only radio links to the antennas with the transmissive radio links.

16. A user equipment, comprising: At least one wireless transceiver; At least two radio links coupled to corresponding antennas; A processor; And A computer-readable storage medium including instructions that, when executed by the processor, are configured to instruct the user equipment to perform any one of the methods of claims 1 to 15 using the at least one wireless transceiver and the at least two radio links.

17. A system-on-chip, comprising: A transceiver module including a transmitter module and a receiver module; An interface to at least a first radio link capable of performing transmit and receive operations; An interface to at least a second radio link capable of performing receive operations; A memory storing radio link offset information; A processor core configured to execute processor-executable instructions; and A computer-readable storage medium including instructions that, when executed by the processor core, direct the apparatus embodying the system-on-chip to perform the method of any one of claims 1 to 15.

18. A computer-readable storage medium including instructions that, when executed by a processor, cause performance of the method of any one of claims 1 to 15.

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