SRS Resource Adaptation for 5G Radar Coexistence
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Solution Overview
Problem
Existing 5G systems face interference issues when coexisting with high-power narrowband systems like RADAR, affecting uplink channel estimation, MIMO operations, and beam management due to overlapping resource blocks, leading to unreliable SRS transmissions.
Innovation Solution
Implement mechanisms such as moving SRS transmissions out of interference bands, increasing OFDM symbols and repetition factors, dynamically switching/suspending SRS, and power boosting to mitigate interference from RADAR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SRS transmissions are performed in overlapping resource blocks with RADAR, then uplink channel estimation can be performed, but interference from RADAR degrades reliability
Solution Approach 1:
The patent extracts the SRS transmissions from the interfered frequency bands by identifying and excluding RADAR-occupied resource blocks from SRS transmission resources. The gNB detects RADAR signals and dynamically adjusts SRS resource allocations to avoid overlapping with RADAR bands, thereby removing the harmful interference effect while maintaining uplink channel estimation capability.
Solution Approach 2:
The patent implements dynamic adjustment of SRS transmission parameters based on real-time RADAR detection. The gNB continuously monitors for RADAR signals and dynamically modifies SRS resource block assignments, transmission timing, and frequency locations to avoid interference. This dynamic adaptation allows the system to maintain reliable SRS transmissions even in the presence of intermittent RADAR activity.
2Object-affected harmful factors
If SRS transmissions are moved out of interference bands, then interference is reduced, but channel estimation accuracy may deteriorate
Solution Approach 1:
The patent applies local quality by performing channel estimation using SRS transmissions on non-interfered resource blocks and then extrapolating or interpolating the channel state information to the entire bandwidth including RADAR-affected regions. The gNB maintains high measurement precision by using clean frequency regions for actual measurements while still obtaining channel information for all resource blocks through signal processing techniques.
Solution Approach 2:
The patent uses SRS transmissions on interference-free resource blocks as intermediaries to infer channel conditions in RADAR-affected bands. By measuring channel properties on clean frequency resources and using these measurements to predict or estimate channel behavior in interfered regions, the system maintains accurate channel estimation without requiring direct transmissions in the harmful interference zones.
3Reliability
If power boosting is applied to SRS transmissions, then signal strength increases, but interference to RADAR system increases
Solution Approach 1:
The patent extracts SRS transmissions from frequency bands occupied by RADAR, eliminating the need for power boosting in those specific regions. By allocating SRS resources only in non-interfered frequency bands, the system achieves reliable SRS reception without generating harmful interference to RADAR operations. This frequency-domain separation removes the trade-off between signal strength and interference generation.
Data Source
AI summary
Examples for ensuring robust SRS transmission and reception can occur when coexisting with interference include moving WTRU SRS transmissions out of the interference band to mitigate interference to and from the interferer, increasing the number of OFDM symbols and/or the repetition factor for SRS to overcome the interference, dynamic switching/suspending of semi-persistent SRS and/or aperiodic SRS to mitigate interference to and from the interferer, and power boosting of SRS transmissions to overcome the interference.