Full-Duplex Beam Precoding for Cross-Link Interference Mitigation
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Solution Overview
Problem
Cross-link interference (CLI) in full-duplex networks degrades wireless communications by causing interference between uplink and downlink messages, making it difficult for UEs to decode downlink messages effectively.
Innovation Solution
A first UE encodes and precodes an uplink message into separate portions using different modulation and coding schemes (MCS) and precoding matrices based on different communication links, allowing a second UE to decode the interference as noise and perform interference cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex operations are implemented to improve spectrum efficiency, then productivity increases, but cross-link interference degrades communication quality
Solution Approach 1:
The uplink message is divided into two separate portions: a first portion encoded with a first MCS for downlink reception, and a second portion encoded with a second MCS for uplink reception. This segmentation allows the victim UE to decode the downlink message while treating the uplink transmission as interference, thereby resolving the CLI issue while maintaining full-duplex operation benefits
Solution Approach 2:
Different portions of the uplink message are assigned different MCS values tailored to their specific reception requirements. The first portion uses a first MCS optimized for downlink decoding by the victim UE, while the second portion uses a second MCS optimized for uplink decoding by the network entity, allowing each portion to serve its local function effectively
2Reliability
If separate encoding of uplink message portions is implemented to mitigate CLI, then communication quality improves, but device complexity increases
Solution Approach 1:
The uplink message is segmented into two portions with different MCS encodings. This segmentation enables the victim UE to selectively decode the first portion for downlink reception while treating the second portion as interference, thereby improving communication quality without requiring complete redesign of the communication system
Solution Approach 2:
The uplink transmission that originally causes harmful interference to the downlink message is converted into a beneficial signal. By encoding the first portion of the uplink message with a first MCS, the victim UE can decode this portion and use it to cancel interference, transforming the harmful uplink signal into a useful interference cancellation resource
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Some wireless communications systems may support cross link interference (CLI) mitigation in full-duplex operations. For example, a first user equipment (UE) may encode and precode a first portion of a message according to a first modulation and coding scheme (MCS) and a first precoding matrix and a second portion of the message according to a second MCS and a second precoding matrix. The first precoding matrix may be based on a first communication link between the first UE and a network entity and the second precoding matrix may be based on the first communication link and a second communication link between the first UE and a second UE. The first UE may transmit the first portion of the message and the second portion of the message via beams associated with respective precoding matrices.