ARQ Protocol Decoupling for Multiuser MIMO Scheduling
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies due to uncertainties in predicting user rates for multi-user MIMO downlink transmissions, leading to outages and suboptimal resource utilization, as interference levels and channel conditions are not accurately known at the time of scheduling.
Innovation Solution
A method that decouples ARQ protocol parameters from scheduling decisions, allowing for independent optimization of ARQ blocks and scheduling weights based on estimated channel quality and user-specific constraints, enabling efficient data transmission through MIMO systems by updating scheduling weights and selecting precoded data blocks in response to feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scheduling decisions are made based on estimated channel quality and interference levels, then user rate prediction and resource allocation can be performed, but uncertainty in interference levels and channel conditions leads to outages and suboptimal resource utilization
Solution Approach 1:
The patent segments the scheduling decision process into two independent parts: (1) ARQ parameter optimization based on channel quality distribution, and (2) scheduling weight update based on feedback. This segmentation allows each part to be optimized independently, reducing the coupling effects that cause uncertainty in rate prediction while maintaining overall system throughput.
Solution Approach 2:
The patent performs preliminary optimization of ARQ parameters based on the channel quality distribution before actual scheduling decisions are made. By pre-optimizing parameters such as block length and coding rate according to the statistical characteristics of the channel, the system reduces uncertainty in rate prediction and prevents outages before they occur.
2Productivity
If ARQ protocol parameters are coupled with scheduling decisions, then joint optimization can be performed, but the complexity of simultaneous optimization increases and prevents independent optimization of ARQ blocks and scheduling weights
Solution Approach 1:
The patent divides the joint optimization problem into two separate sub-problems: ARQ parameter optimization and scheduling weight optimization. Each sub-problem can be solved independently using appropriate algorithms, avoiding the computational complexity of simultaneous joint optimization while achieving comparable or better performance through decoupled optimization.
Solution Approach 2:
The patent extracts the ARQ parameter optimization from the scheduling decision process and treats them as separate optimization problems. By taking out the ARQ parameters and optimizing them based on channel quality distribution independently from scheduling weights, the system reduces algorithmic complexity while maintaining optimization efficiency.
3Productivity
If maximum instantaneous rates are pursued, then system throughput is maximized, but decoding delay constraints may be violated and outages increase
Solution Approach 1:
The patent changes the ARQ parameters (block length, coding rate, modulation scheme) based on the channel quality distribution to achieve the maximum instantaneous rate while satisfying decoding delay constraints. By dynamically adjusting these parameters according to the statistical characteristics of the channel, the system optimizes throughput without violating delay requirements or increasing outage probability.
Data Source
AI summary
A method and apparatus is disclosed herein for performing wireless communication. In one embodiment, the apparatus comprises a processing unit to run a scheduling selection algorithm to update user terminal scheduling weights in response to scheduling feedback transmitted by a plurality of user terminals by an end of an immediately preceding scheduling event; a scheduler and precoder, responsive to the updated user terminal scheduling weights generated by the scheduling algorithm and channel estimates of user terminals, to choose a set of user terminals for scheduling and to choose precoder beams and their power for such user terminal in the set of user terminals; a plurality of precoding blocks to receive one coded ARQ block for at least one packet for each user terminal in the set and, responsive to the precoder beams, to generate precoded data, where the one coded ARQ block is one of a plurality of ARQ blocks generated for a single packet and being generated using a single ARQ scheme for such each user terminal; and a transmitter to transmit the precoded data using MIMO transmission.