Full-Duplex Wireless Scheduling for Cross-Link Interference Mitigation
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 solution involves determining uplink and downlink resources using a Channel Quality Index (CQI) parameter and AI/ML engine to optimize frequency resource allocation, delaying downlink transmissions, and employing AI/ML to identify low-interference scenarios for user equipment devices, thereby mitigating CLI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex operation is implemented to boost spectrum efficiency, then productivity is improved, but cross link interference increases worsening reliability
Solution Approach 1:
The frequency resources are segmented into different groups (first group and second group) for uplink and downlink transmissions respectively. This segmentation allows the system to allocate specific frequency bands to specific directions, reducing cross-link interference while maintaining full duplex operation. The base station schedules transmissions based on these segmented frequency groups, enabling simultaneous uplink and downlink without mutual interference.
Solution Approach 2:
Different quality requirements for different communication types are addressed by applying different frequency allocation strategies. For example, URLLC traffic receives prioritized allocation in the first frequency group with stricter interference protection, while other traffic can be allocated in the second group with more flexible spacing. This local quality approach ensures that critical communications maintain high reliability while allowing overall system productivity to benefit from full duplex operation.
2Reliability
If downlink transmission is delayed to cancel cross link interference, then reliability is improved, but loss of time increases
Solution Approach 1:
The base station receives advance scheduling information from neighboring base stations about when downlink transmissions will occur. Using this preliminary knowledge, the system can pre-allocate frequency resources and schedule uplink transmissions in a way that avoids interference from upcoming downlink transmissions. This eliminates the need for reactive delays while maintaining interference cancellation capability.
Solution Approach 2:
The system introduces an intermediary coordination mechanism where base stations exchange scheduling information with neighboring base stations. This intermediary communication layer enables coordinated frequency allocation across multiple cells, allowing the system to manage cross-link interference through collaborative scheduling rather than unidirectional delay, thus reducing overall time loss.
3Productivity
If frequency resources are allocated closer together to reduce resource usage, then productivity is improved, but cross link interference increases worsening reliability
Solution Approach 1:
The frequency allocation strategy is made dynamic rather than static. The base station determines the appropriate spacing between uplink and downlink frequency resources based on real-time channel quality indicators (CQI) and interference conditions. When channels are clean and interference is low, resources are allocated closer together to maximize utilization. When interference is detected, the system dynamically increases spacing or reallocates resources to maintain reliability.
Solution Approach 2:
The system changes the allocation parameters (frequency spacing, resource group assignment) based on measured channel conditions. By monitoring CQI and interference levels, the base station adjusts the frequency resource allocation parameters dynamically. This allows the system to optimize the balance between resource utilization and interference protection, allocating resources efficiently while maintaining reliability through parameter adaptation.
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.