Sidelink Interference Management for TDD Systems
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Solution Overview
Problem
Wireless communication systems, particularly in higher frequency spectrum bands, face challenges with cross-link interference (CLI) in time division duplexing (TDD) arrangements, leading to limited coverage and unsatisfactory performance for uplink-centric use cases, as base stations interfere with each other while transmitting and receiving in the same frequency band.
Innovation Solution
The use of sidelink resources to identify and manage interference by transmitting a conditional grant to user equipment (UE), which monitors sidelink resources for interference indications and transmits acknowledgments to the base station, allowing dynamic resource allocation and interference mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TDD arrangements are used in higher frequency spectrum bands, then system capacity and frequency utilization are improved, but cross-link interference between base stations increases
Solution Approach 1:
The base station transmits a conditional grant to the UE in advance, which includes an indication to monitor sidelink resources for interference detection. This preliminary action allows the UE to prepare for potential interference scenarios before actual uplink communication occurs, enabling proactive interference management rather than reactive mitigation.
Solution Approach 2:
The patent introduces sidelink resources as an intermediary mechanism between the base station and UE for interference detection. Instead of direct base station-to-base station interference measurement, the UE acts as an intermediary by monitoring sidelink resources that carry interference indications from other base stations' UEs, thus indirectly detecting cross-link interference affecting the scheduled uplink resource.
2Use of energy by moving object
If base stations transmit and receive in the same frequency band simultaneously, then frequency utilization is improved, but coverage is limited due to interference
Solution Approach 1:
The patent implements a feedback mechanism where the UE monitors sidelink resources for interference indications and reports back to the base station whether the scheduled resource is suitable for communication. This feedback loop enables the base station to make informed decisions about resource allocation, adjusting grants based on actual interference conditions observed by the UE, thus maintaining coverage quality while utilizing frequency efficiently.
3Reliability
If conditional grants with sidelink monitoring are implemented, then interference management is improved, but device complexity increases
Solution Approach 1:
The patent extracts the interference detection function from the base station and places it at the UE level through sidelink monitoring. By taking out this function and implementing it at the edge device (UE), the system leverages the UE's existing sidelink capabilities rather than requiring complex base station coordination, thus improving interference management while keeping the added complexity localized to the UE.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Aspects of the disclosure describe using sidelink resources to identify possible interference (e.g., including cross-link interference) in a first resources used for communications between a base station and a user equipment (UE). With such techniques, a base station may transmit a conditional grant to a UE that schedules resources for the UE to use to communicate with the base station (e.g., either uplink or downlink). The UE may monitor sidelink resources to identify an indication of interference for the resources scheduled by the conditional grant. Different UEs may exchange messages or may transmit energy over the sidelink network to indicate resources are being used to communicate between base stations and UEs. The UE may transmit an acknowledgement or a negative acknowledgement to the base station indicating whether the resources scheduled by the conditional grant are to be used by the UE.