MU-MIMO Transmitter Dynamic Receiver Grouping for CSI Acquisition
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Solution Overview
Problem
MU-MIMO transmission schemes face inefficiencies in channel state information (CSI) acquisition due to the linear growth of downlink pilot sequence length and feedback data with large antenna arrays, which can reduce payload transmission time and compromise Quality of Service (QoS) fairness among receivers.
Innovation Solution
Dynamic grouping of receivers based on channel correlations and transmission priorities, using a two-tier precoding strategy with adaptive re-grouping and re-prioritization to optimize CSI feedback and resource allocation, allowing for periodic monitoring and updating of group assignments and priorities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If downlink pilot sequences are used for CSI acquisition, then channel state information can be obtained, but the pilot sequence length and feedback data size grow linearly with antenna array size, reducing payload transmission time
Solution Approach 1:
The patent segments the antenna array into multiple sub-arrays, where each sub-array is independently controlled and processed. This segmentation reduces the effective antenna array size for CSI acquisition, thereby reducing pilot sequence length and feedback overhead while maintaining overall system performance through coordinated processing of multiple sub-arrays.
2Productivity
If receivers are grouped for MU-MIMO transmission, then CSI acquisition efforts are reduced, but the transmitter loses freedom to attend to individual QoS demands and traffic conditions
Solution Approach 1:
The patent implements dynamic receiver grouping where the grouping configuration is not fixed but can be adjusted in real-time based on QoS requirements, traffic conditions, and channel states. This dynamic adaptation allows the system to optimize CSI acquisition efficiency through grouping while simultaneously maintaining the ability to cater to individual receiver requirements by reconfiguring groups as needed.
Solution Approach 2:
The patent applies different grouping strategies and resource allocation policies to different receiver groups based on their specific QoS requirements and traffic characteristics. High-priority receivers with stringent QoS demands receive dedicated or preferential treatment within their groups, while other receivers use standard grouping benefits, thereby maintaining both efficiency and adaptability.
3Productivity
If large antenna arrays are used, then transmission bit rate increases, but CSI acquisition time increases, reducing the time available for payload transmission
Solution Approach 1:
The patent segments the large antenna array into multiple smaller sub-arrays that can be independently processed for CSI acquisition. This segmentation reduces the pilot sequence length and feedback overhead for each sub-array, thereby reducing total CSI acquisition time while maintaining the high transmission bit rate capability of the full array through parallel or coordinated processing.
Solution Approach 2:
The patent applies partial action by acquiring CSI for only the most relevant or priority receivers at any given time, rather than all receivers simultaneously. This selective CSI acquisition reduces overall acquisition time while maintaining sufficient system performance by focusing resources on critical links.
Data Source
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AI summary
Provided is a multi-user multiple-input multiple-output (MU-MIMO), transmitter, adapted to acquire channel state information (CSI), from a plurality of receivers. The transmitter is configured to operate a radio antenna array to establish signal paths between antennas of the antenna array and a plurality of receivers. The transmitter comprises a mapper configured to dynamically group, for a given time interval, the plurality of receivers to MU-MIMO groups, wherein the grouping is based on information indicating correlations between signal paths from the antennas to the receivers and a transmission priority of each receiver. The transmitter further comprises a selector configured to select, for the given time interval, receivers from which CSI is to be received, and to identify one or more of the MU-MIMO groups based on the selected receivers.