Cross-Link Interference Cancellation in TDD Wireless Systems
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Solution Overview
Problem
Cross-link interference (CLI) occurs in wireless multiple-access communications systems, particularly in time division duplexing (TDD) and full duplexing (FD) configurations, where uplink transmissions from one user equipment (UE) interfere with downlink receptions of another UE, leading to communication disruptions.
Innovation Solution
The system enables CLI cancellation by allowing a victim UE to signal its CLI cancellation capability to a serving base station. The base station then assists the victim UE with channel estimation during a training phase, using assistance information that may be obtained directly or indirectly from the aggressor UE, to facilitate effective CLI cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TDD or full duplexing configurations are used to increase system capacity and flexibility, then productivity and adaptability improve, but cross-link interference occurs between uplink and downlink transmissions
Solution Approach 1:
The patent converts the harmful CLI signal into a useful channel estimation reference. The victim UE uses the aggressor UE's uplink transmission (which causes interference) as a reference signal to estimate the interference channel, then subtracts this estimated interference from the received downlink signal, transforming the harmful interference into a beneficial cancellation mechanism
Solution Approach 2:
The patent introduces channel estimation as an intermediary process between the interference occurrence and the final reception. By estimating the interference channel characteristics through reference signals and using this estimation to predict and remove the CLI component, the system mediates the harmful interaction between uplink and downlink transmissions
2Reliability
If CLI cancellation capability signaling and channel estimation training are implemented, then reliability of downlink reception improves, but device complexity and loss of information increase
Solution Approach 1:
The victim UE autonomously performs channel estimation and interference cancellation using its own receiver capabilities and locally processed reference signals. The UE self-determines its CLI cancellation capability and self-executes the cancellation algorithm without requiring complex network-side coordination or additional infrastructure
Solution Approach 2:
The patent performs channel estimation during a training phase before actual data reception. Reference signals are processed in advance to establish the interference channel characteristics, so that when downlink data arrives, the cancellation is already prepared and can be applied immediately, improving reliability without adding complexity to the data path
Data Source
AI summary
Systems and techniques are provided for performing wireless communications at a user equipment (UE). For example, a process can include transmitting, from a UE based on a cross-link interference (CLI) cancellation capability of a receiver of the UE, a CLI cancellation capability indication. The process can include receiving, at the UE, a communications signal. In some implementations, the UE received the communications signal from a network entity. In some cases, receiving the communications signal from the network entity at least partially coincides with a transmission of an additional communications signal by an additional UE, wherein the additional UE is different from the UE.