Multi-User Scheduling via Effective SINR for HARQ Fairness
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Solution Overview
Problem
Existing multi-user scheduling approaches in wireless communication systems fail to properly guarantee user fairness during retransmissions, especially in scenarios involving hybrid automatic repeat request (HARQ) schemes, as they do not adequately account for the combining gain and processing effects on signal-to-interference-plus-noise ratio (SINR).
Innovation Solution
A method that adjusts and combines SINR for initial and retransmission to calculate effective SINR, incorporating HARQ combining gain, which is then used to derive a priority metric for scheduling, allowing for accurate measurement of instantaneous throughput and fairness in multi-user scheduling, particularly through schemes like Chase combining, incremental redundancy, and hybrid approaches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multi-user scheduling algorithms are used, then system throughput can be optimized, but user fairness during retransmission cannot be properly guaranteed
Solution Approach 1:
The patent changes the parameter used for scheduling decisions from raw SINR to effective SINR that incorporates HARQ combining gain. By adjusting the SINR parameter to reflect the actual combined signal quality after HARQ processing, the system can make more accurate scheduling decisions that maintain both throughput and fairness during retransmission scenarios
Solution Approach 2:
The patent implements a feedback mechanism where the network node determines HARQ combining gain based on previous transmission outcomes and channel conditions, then uses this feedback to adjust the effective SINR calculation. This closed-loop approach ensures that scheduling decisions account for the actual performance of retransmissions, maintaining user fairness while preserving system throughput
2Device complexity
If HARQ combining gain is not accounted for in SINR calculation, then scheduling decisions are simpler, but instantaneous throughput measurement becomes inaccurate
Solution Approach 1:
The patent performs preliminary calculation of HARQ combining gain before the scheduling decision is made. By pre-determining the combining gain based on available channel state information and previous transmission data, the system avoids complex real-time calculations during scheduling while ensuring accurate instantaneous throughput measurement through the effective SINR metric
Data Source
AI summary
The present invention discloses a network node (100) for multi-user scheduling involving retransmission. The network node comprises a receiver (110) adapted to receive channel quality indicator (CQI) report from a user equipment (UE), an adjuster (120) adapted to adjust signal to interference and noise ratio (SINR) derived from the CQI report to obtain SINR for retransmission, a combiner (130) adapted to combine SINR for initial transmission and SINR for one or a plurality of retransmission to obtain effective SINR, and a scheduler (140) adapted to perform multi-user scheduling on the basis of priority metric derived from the effective SINR. The present invention improves multi-user scheduling by taking HARQ combining gain into account. Instantaneous throughput as well as priority metric can be accurately measured, because SINR from not only channel quality (e.g. CQI) but also HARQ processing gain are both included.