Multi-Point Feedback Using Single Beam Combination
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Solution Overview
Problem
In multi-point (MP) communications systems, the transmission of large numbers of sounding reference signals (SRS) for channel estimation consumes significant beamformed uplink resources, particularly in link-budget limited environments like millimeter wave (mmWave) systems, leading to performance degradation and increased interference.
Innovation Solution
The system and method provide explicit feedback by transmitting downlink channel responses using the best uplink beam combination, reducing the need for multiple UE to TRP beamformed links, thereby minimizing interference and optimizing resource utilization through the use of a single transmit-receive beam combination per TRP for conveying feedback across multiple TRBCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a UE transmits a large number of SRS symbols to facilitate channel estimation between each transmit antenna and each receive antenna at each access node in MP communications, then channel estimation accuracy is improved, but uplink resource consumption increases significantly and system performance deteriorates
Solution Approach 1:
The patent combines channel estimation for multiple TRPs and multiple antenna ports into a single SRS transmission process. Instead of requiring separate SRS transmissions for each TRP-antenna combination, the system enables a UE to transmit one SRS that allows all TRPs to estimate channels to all their receive antennas simultaneously, thereby reducing uplink resource consumption while maintaining estimation accuracy
Solution Approach 2:
The patent makes a single SRS transmission serve multiple functions: it enables channel estimation for multiple TRPs, multiple receive antenna ports, and multiple beam combinations simultaneously. This multi-functional approach eliminates the need for dedicated SRS resources for each TRP-antenna combination, significantly reducing overall uplink resource consumption
2Reliability
If beamformed SRS transmissions are used to meet performance requirements in mmWave environments with high path-loss, then link reliability is improved, but the overhead of transmitting large numbers of SRS symbols increases
Solution Approach 1:
The patent merges the feedback transmissions for multiple beam combinations into a single uplink transmission opportunity. Instead of requiring separate feedback messages for each beam combination, the system enables the UE to convey all necessary feedback information in one transmission, reducing overhead while maintaining the reliability benefits of beamformed communications
3Reliability
If multiple UE to TRP beamformed links are used for feedback transmission, then feedback coverage is improved, but interference increases and resource utilization decreases
Solution Approach 1:
The patent consolidates multiple feedback transmissions into a single unified feedback message transmitted over one beamformed link. This merging approach reduces the number of simultaneous transmissions, thereby minimizing inter-cell interference while maintaining comprehensive feedback coverage through the use of beamforming techniques
Data Source
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AI summary
A method for transmitting feedback includes receiving feedback configuration information for explicit channel feedback for a plurality of transmit beam-receive beam combinations (TRBCs) between the user device and transmit-receive points (TRPs) of a multi-point set associated with the user device, generating the explicit channel feedback for the plurality of TRBCs, generating at least one modified uplink resource for each TRP in a subset of the TRPs of the multi-point set, the modified uplink resources are generated in accordance with the feedback configuration information, the modified uplink resources are configured to convey the explicit channel feedback to the subset of TRPs of the multi-point set, and transmitting the modified uplink resources to the subset of the TRPs of the multi-point set, where the at least one modified uplink resource associated with a TRP in the subset of the TRPs is transmitted to the TRP using a single TRBC.