Full-Duplex Resource Scheduling for 5G Cross-Link Interference
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Solution Overview
Problem
In mobile wireless communication systems, particularly in 5G networks operating in full duplex mode, there is a challenge of mitigating intra-operator interference between uplink and downlink resources, which is exacerbated by Cross-Link Interference (CLI) and reduced link budget in Time Division Duplex (TDD) scenarios.
Innovation Solution
The system allocates uplink and downlink resources based on Channel Quality Index (CQI) to minimize interference, using AI/ML for dynamic resource assignment, and employs techniques like creating guard bands and scheduling resources to isolate uplink and downlink channels, especially for Ultra Reliable Low Latency Communication (URLLC) traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex mode is implemented to increase spectrum utilization, then productivity is improved, but intra-operator interference increases
Solution Approach 1:
The available frequency bandwidth is segmented into multiple subbands, with some subbands configured for uplink and others for downlink within the same time slot. This segmentation allows full duplex operation while isolating uplink and downlink frequencies to prevent intra-operator interference.
Solution Approach 2:
Different portions of the frequency spectrum are assigned different qualities (uplink or downlink) based on local interference conditions and traffic demands. The base station dynamically configures which subbands are uplink and which are downlink, allowing optimized local quality assignment to minimize interference.
2Productivity
If downlink resources are allocated closer to uplink resources to reduce frequency spacing, then productivity is improved, but interference increases
Solution Approach 1:
The frequency allocation between uplink and downlink is made dynamic rather than fixed. The base station continuously monitors channel conditions and adjusts the allocation of subbands to uplink or downlink based on real-time interference levels and traffic demands, optimizing the balance between resource efficiency and interference mitigation.
Solution Approach 2:
The system changes parameters such as the frequency spacing between uplink and downlink subbands, and the allocation ratios, based on measured interference levels and channel quality indicators. This allows adaptive optimization of the frequency domain resource allocation.
3Adaptability or versatility
If dynamic resource allocation based on CQI is implemented, then adaptability is improved, but device complexity increases
Solution Approach 1:
The base station receives Channel Quality Indicators (CQI) from user equipment as feedback about downlink channel conditions. This feedback is used to dynamically adjust uplink and downlink resource allocation, ensuring that users with poor channel conditions are allocated resources that minimize interference and maximize reliability.
Solution Approach 2:
The system uses automatically measured CQI values and predefined allocation rules to make resource allocation decisions without requiring complex manual configuration. The base station autonomously adjusts resource distribution based on real-time channel conditions, reducing the need for complex external control.
Data Source
AI summary
Uplink and downlink resources within a wireless network are assigned such that interference is mitigated. An uplink resource and a downlink resource are each specified by a respective time domain resource and frequency domain resource, and chosen to enable full duplex operation at least part of the time. A relative spacing between the frequency domain resource allocated for the uplink and the frequency domain resource allocated for the downlink is then chosen depending on a Channel Quality Index (CQI) or some other indicator of radio frequency (RF) signal strength.