Symbol-by-Symbol SRS Randomization for TDD Coherent Joint Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In time division duplex (TDD) systems, increasing the number of transmitter antennas for coherent joint transmission (CJT) leads to challenges in obtaining accurate Channel State Information at Transmitter (CSIT), and existing SRS resource allocation methods face limitations in capacity and interference, particularly with cross-SRS interference.
Innovation Solution
Implementing symbol-by-symbol randomization of SRS resource configurations, including cyclic shifts, comb offsets, and TD-OCC, using cell-specific and UE-specific identities to enhance SRS resource allocation, reducing cross-SRS interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of orthogonal resources are used to increase SRS capacity, then the system SRS capacity increases, but the system has a finite number of resources available making unlimited assignment impractical
Solution Approach 1:
The patent applies dynamics by making the SRS resource configuration time-varying through symbol-by-symbol randomization. The cyclic shift, comb offset, and TD-OCC are randomized based on cell ID and UE ID for each symbol, allowing the system to dynamically reuse resources across different time instances while maintaining orthogonality and avoiding continuous interference.
2Productivity
If SRS resources are allocated to accommodate more users and antenna ports, then the system capacity increases, but interference to the lowest possible level cannot be completely eliminated
Solution Approach 1:
The patent converts the harmful cross-SRS interference into a beneficial effect by using the interference pattern to drive the randomization process. The interference from different UEs is transformed into a mechanism that distributes resources more evenly across the frequency domain, with the comb offset randomization ensuring that interference is spread out rather than concentrated at specific resource elements.
3Device complexity
If fixed SRS resource configurations are used, then the allocation is simple, but continuous interference occurs across TRPs
Solution Approach 1:
The patent applies periodic action through the symbol-by-symbol randomization process that repeats every SRS symbol. The cyclic shift and comb offset are updated periodically based on the symbol index and user identifiers, creating a rhythmic pattern of resource allocation that prevents continuous interference while maintaining implementation simplicity.
Data Source
AI summary
A method includes receiving, at a user equipment device (UE) from a transmission and reception point (TRP), an uplink CSI measurement configuration including a sounding reference signal (SRS) resource configuration indicating one or more of SRS resource randomization configurations of a cyclic shift, a comb offset, and a time domain orthogonal cover code (TD-OCC); and transmitting SRSs in a sequence of symbols, according to the SRS resource configuration, wherein the SRSs are determined according to the one or more of SRS resource randomization configurations of the cyclic shift, the comb offset, and the TD-OCC, values of the one or more of SRS resource randomization configurations being randomized symbol-by-symbol according to at least one of a cell-specific identity (IDcell) and a UE-specific identity (IDue).