CQI Feedback for Full-Duplex LTE Joint Scheduling
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Solution Overview
Problem
The increasing prevalence of full-duplex cellular systems in high-density environments leads to significant interference between uplink and downlink transmissions, particularly in LTE networks, due to UEs and eNBs operating in close proximity, which existing technologies have not adequately addressed.
Innovation Solution
Implementing joint scheduling techniques at eNBs to manage interference by coordinating uplink and downlink transmissions, utilizing channel quality information and interference mitigation strategies, especially in environments with varying UE densities and mobility patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex systems are implemented to allow simultaneous uplink and downlink transmissions, then spectrum efficiency is improved, but co-channel interference between UEs increases
Solution Approach 1:
The patent implements a feedback mechanism where UEs report interference measurements (CQI feedback) to the eNB. The eNB uses this feedback to identify aggressor UEs causing interference and adjusts scheduling decisions accordingly, enabling the system to maintain full-duplex operation while mitigating interference through continuous monitoring and adaptation.
Solution Approach 2:
The patent employs dynamic scheduling where the eNB makes real-time scheduling decisions based on current interference conditions. The system dynamically pairs uplink and downlink UEs by evaluating interference metrics and adjusting resource allocation in each scheduling interval, allowing the network to adapt to changing interference patterns while maintaining high spectrum utilization.
2Area of stationary object
If UEs are disposed proximate to each other in high-density environments, then network coverage is improved, but UE-to-UE interference increases
Solution Approach 1:
In high-density environments, the feedback mechanism becomes even more critical as UEs are closer and interference patterns change more frequently. The system continuously collects CQI feedback from UEs and uses this information to identify and manage interfering pairs, enabling the network to maintain coverage in dense areas while mitigating the increased interference through informed scheduling decisions.
Solution Approach 2:
The patent applies local quality by making scheduling decisions specific to each UE pair rather than using uniform scheduling across the cell. The eNB evaluates interference conditions locally for each potential uplink-downlink pair and makes customized scheduling decisions, allowing the system to optimize performance for each local interference scenario in the high-density environment.
3Reliability
If joint scheduling is implemented to mitigate interference, then interference management capability is improved, but scheduling complexity increases
Solution Approach 1:
The patent segments the interference management problem by evaluating uplink and downlink UEs separately and then forming pairs based on compatibility. Rather than optimizing the entire system simultaneously, the eNB divides the scheduling task into manageable steps: collecting feedback from individual UEs, identifying aggressor UEs, and forming uplink-downlink pairs. This segmentation reduces computational complexity while maintaining effective interference management.
Solution Approach 2:
The system performs preliminary actions by collecting CQI feedback from all UEs before making scheduling decisions. The eNB pre-identifies potential aggressor UEs and evaluates interference conditions in advance, allowing it to make informed pairing decisions without having to perform complex real-time optimization during the actual scheduling moment. This preliminary evaluation simplifies the final scheduling decision process.
Data Source
AI summary
Devices and methods of providing joint scheduling in a full-duplex LTE system are generally described. The UE measures intra-cell interference at the UE caused by a UL transmission from each intra-cell UE, calculates a ratio of the intra-cell interference over an average inter-cell interference, determines whether the intra-cell UE is an aggressor or non-aggressor based on whether the ratio exceeds a threshold, transmits at least some of the determinations to the eNB as feedback, and communicates with the eNB based on a schedule that is dependent on the feedback such that the UE is neither an aggressor nor is subject to interference from aggressors. The schedule may also be based on wideband CQI feedback based on a ratio of an average overall DL interference plus noise over the average inter-cell interference plus noise and/or subband. CQI feedback based on SINR measurements.