Sounding Reference Signal Sequence Encoding for Subband Interference Reporting
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Solution Overview
Problem
In wireless communication networks, especially in industrial IoT settings with tight latency requirements, it is challenging for user equipment (UE) to efficiently report interference across multiple subbands due to increased latency in interference measurements, which can impact the reliability of communication links.
Innovation Solution
The UE autonomously performs interference measurements across multiple subbands and transmits sounding reference signals (SRS) to indicate interference levels, allowing the base station to reconfigure communication schedules and retransmissions to subbands with lower interference, thereby reducing latency and improving communication reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE performs interference measurements across multiple subbands using conventional methods, then the interference reporting becomes more comprehensive, but the latency increases and reliability decreases
Solution Approach 1:
The SRS signal is designed to serve multiple functions simultaneously: it acts as both a standard uplink reference signal for channel estimation and carries interference measurement information through its sequence selection. This multi-functionality eliminates the need for separate interference measurement reporting channels, thereby reducing latency while maintaining comprehensive interference assessment across multiple subbands.
Solution Approach 2:
The interference level information is encoded by changing the SRS sequence parameter (selecting from multiple predefined sequences with different cyclic shifts). Different sequences represent different interference levels (e.g., low, medium, high), allowing the UE to convey measurement results efficiently without additional time delay for separate reporting.
2Loss of information
If the UE transmits separate interference reports for each subband, then the interference information becomes more detailed, but the signaling overhead and latency increase
Solution Approach 1:
The patent combines multiple interference measurement results from different subbands into a single SRS transmission event. The UE selects appropriate SRS sequences for each subband and transmits them together, merging what would otherwise be separate reporting operations into one unified action, thereby reducing total reporting time while preserving complete interference information across all subbands.
Solution Approach 2:
The SRS mechanism is extended to universally handle both channel sounding and interference reporting functions. By encoding interference levels through sequence selection, the same uplink resource serves dual purposes, eliminating the need for dedicated interference reporting transmissions and reducing overall signaling latency.
3Ease of operation
If the base station uses fixed scheduling for PDSCH reception, then the scheduling is simpler, but it cannot adapt to varying interference conditions across subbands
Solution Approach 1:
The UE provides feedback to the base station by transmitting SRS sequences that indicate measured interference levels in different subbands. The base station uses this feedback information to dynamically adjust its scheduling decisions, selecting subbands with lower interference for PDSCH transmissions. This feedback mechanism enables adaptive scheduling that responds to real-time interference conditions while maintaining reasonable operational complexity.
Solution Approach 2:
The scheduling system transitions from a static, fixed schedule to a dynamic schedule that can adapt to changing interference conditions. The base station modifies PDSCH allocation based on interference levels reported through SRS sequences, allowing the system to flexibly respond to varying radio conditions across different subbands and time instances.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may perform a first interference measurement on a first subband of a plurality of subbands configured for the UE and a second interference measurement on a second subband of the plurality of subbands. The UE may identify a first interference level based at least in part on the first interference measurement and a second interference level based at least in part on the second interference measurement. The UE may transmit, to a base station, a first sounding reference signal (SRS) on the first subband and a second SRS on the second subband, wherein an SRS sequence of the first SRS indicates the first interference level, and wherein an SRS sequence of the second SRS indicates the second interference level. Numerous other aspects are provided.