Wireless Communication System Mode Switching for Feedback Reduction
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Solution Overview
Problem
In wireless communication systems, the existing methods face challenges in achieving high communication speeds and reducing feedback volume, particularly when multiple base stations coordinate with multiple mobile stations, leading to increased channel state information volume and delayed feedback, which deteriorates transmission rates and throughput due to geographical variations in channel state information and high communication protocol overhead.
Innovation Solution
A wireless communication system that automatically switches between MIMO+TDMA, SDMA+TDMA, and multipoint SDMA communication modes based on demand transmission speed, using a base station controller to collect and analyze channel state information, reducing feedback volume by utilizing past channel state information when correlation is high and only updating when necessary, and employing an enhanced preamble signal to minimize channel state information feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple base stations coordinate with multiple mobile stations using multipoint SDMA, then communication capacity and throughput are improved, but channel state information volume and feedback delay increase
Solution Approach 1:
The patent segments the channel state information feedback process by dividing mobile stations into groups and collecting CSI only from representative stations in each group, rather than requiring feedback from all mobile stations. This segmentation reduces the total feedback volume and delay while maintaining system performance through coordinated multi-base station operation.
Solution Approach 2:
The patent applies partial action by collecting channel state information from only a subset of mobile stations (representative stations) rather than all mobile stations in the system. This partial feedback approach is sufficient to enable effective multipoint SDMA coordination without the overhead of complete system feedback.
2Measurement precision
If channel state information is collected from all mobile stations, then transmission rate accuracy is improved, but feedback volume and protocol overhead increase
Solution Approach 1:
The patent extracts only the essential channel state information from representative mobile stations in each group, rather than collecting complete CSI from all mobile stations. This extraction approach captures the critical information needed for transmission rate determination while eliminating redundant feedback data, thereby reducing protocol overhead.
Solution Approach 2:
The system performs partial feedback collection by obtaining CSI from a selected subset of mobile stations rather than the complete set. This partial action provides sufficient measurement precision for transmission rate accuracy while significantly reducing the quantity of feedback information required.
3Device complexity
If feedback is delayed due to large volume of channel state information, then system complexity is reduced, but transmission rate and throughput deteriorate
Solution Approach 1:
The patent segments the feedback collection process into groups of mobile stations with representative stations selected from each group. This segmentation reduces the immediate feedback volume, enabling timely processing without excessive system complexity, thereby maintaining high throughput through coordinated multi-base station transmission.
Solution Approach 2:
The system performs preliminary grouping of mobile stations and selection of representative stations before the feedback collection phase. This preliminary organization enables efficient processing of reduced feedback data, minimizing delay while maintaining the coordination capability needed for high throughput multipoint SDMA operation.
Data Source
AI summary
There is provided a wireless communication system in which a feedback volume is reduced as exceeding a communication speed demanded by a mobile station. The wireless communication system includes: a plurality of base stations 102a and 102b having a plurality of antennas; a plurality of mobile stations 103a to 103d having a plurality of antennas; and a base station controller 101a collectively controlling a plurality of the base stations. During a certain period of time (time slot), there are provided an (MIMO+TDMA) communication mode by which only one of the base stations and one of the mobile stations are communicated with each other, an (SDMA+TDMA) communication mode by which one of the base stations and the plurality of the mobile stations are simultaneously communicated with each other, and a (multipoint SDMA) communication mode by which the plurality of the base stations and the plurality of the mobile stations are simultaneously communicated with each other by coordinating the plurality of the base stations with each other by the base station controller. And, it is judged by the base station or the base station controller whether or not the communication speed requested from the mobile station can be exceeded, so that an appropriate communication mode is automatically decided by switching the communication modes.