Cross-Link Interference Cancellation Through Delayed Downlink Scheduling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cross link interference (CLI) is a significant challenge in full duplex wireless communication systems, particularly in 5G networks, where downlink and uplink operations occur simultaneously, leading to interference issues that affect signal quality and reliability.
Innovation Solution
The proposed solution involves determining uplink and downlink resources using a Channel Quality Index (CQI) parameter and AI/ML engine to optimize frequency resource allocation, canceling CLI by characterizing communication paths, and delaying downlink transmissions to mitigate interference, especially for Ultra Reliable Low Latency Communication (URLLC) traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex operation is implemented to increase spectrum efficiency, then productivity is improved, but cross link interference increases worsening reliability
Solution Approach 1:
The frequency resources are segmented into distinct uplink and downlink regions, with downlink resources allocated to be as far as possible from uplink resources. This spatial separation in the frequency domain reduces cross link interference while maintaining full duplex operation capability.
Solution Approach 2:
The system performs preliminary characterization of communication paths and determines CLI cancellation requirements before actual transmission. The base station is informed of downlink scheduling decisions in advance, allowing for preliminary interference estimation and cancellation preparation.
2Reliability
If downlink transmission is delayed to cancel CLI, then reliability is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary characterization of communication paths and determines CLI cancellation requirements before actual transmission. The base station is informed of downlink scheduling decisions in advance, allowing for preliminary interference estimation and cancellation preparation.
Solution Approach 2:
The system uses feedback mechanisms where the base station is informed of downlink scheduling decisions from neighboring base stations. This feedback enables the base station to adjust its transmission timing and apply appropriate interference cancellation techniques.
3Productivity
If frequency resources are allocated closer together to reduce spacing, then productivity is improved, but cross link interference increases worsening reliability
Solution Approach 1:
The system applies different allocation strategies for different communication types. For URLLC traffic, downlink frequency resources are assigned from within a second group but positioned as far from uplink frequency resources as possible. For other traffic types, the spacing can be optimized based on channel quality indicators.
Solution Approach 2:
The system dynamically adjusts frequency resource allocation based on channel quality indicators (CQI) and interference conditions. The spacing between uplink and downlink frequency resources is modified according to measured interference levels and signal strength.
Data Source
AI summary
Cross Link Interference (CLI) within a wireless network is mitigated by characterizing a communication path that introduces the CLI on an uplink resource. Mitigation is achieved by receiving, from a neighboring device, information related to a downlink resource scheduling decision. The neighboring device then delays its downlink resource transmission. Transmissions received on an uplink resource may then be corrected.