OFDMA Base Station Uplink Overhead Reduction via Grouped Channel Reporting
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Solution Overview
Problem
In OFDMA systems, the current methods for reporting reception quality information from terminals to base stations result in high uplink control overhead, as all mobile stations need to periodically report quality measurements for all frequency channels, leading to inefficient data transmission and increased overhead.
Innovation Solution
A 2-step grouping scheme is implemented, where channels are divided into subgroups and groups, with each terminal reporting representative reception quality information only for its allocated subgroups, reducing the amount of data transmitted to the base station and optimizing scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all mobile stations report reception quality measurements for all frequency channels periodically, then the base station can make accurate scheduling decisions, but the uplink control overhead increases significantly
Solution Approach 1:
The patent divides frequency channels into multiple groups, where each mobile station reports reception quality information only for its allocated group rather than all channels. This segmentation reduces the quantity of reported information while maintaining scheduling accuracy for allocated resources.
Solution Approach 2:
The patent implements differentiated reporting where each mobile station reports reception quality for its specific allocated frequency channels rather than uniformly reporting all channels. This local quality approach ensures each station provides relevant information for its own resource allocation without contributing to overall overhead.
2Loss of information
If reception quality information is reported for all frequency channels, then complete channel state information is available, but the scheduling efficiency decreases due to processing overhead
Solution Approach 1:
The patent extracts and reports only the essential reception quality information for allocated frequency channels, removing unnecessary information about unallocated channels. This extraction maintains sufficient channel state information for effective scheduling while reducing processing overhead and improving scheduling efficiency.
3Reliability
If the number of reported reception quality parameters is increased, then more detailed channel information is provided, but the uplink transmission time increases
Solution Approach 1:
By segmenting frequency channels into groups and having mobile stations report only for their allocated groups, the patent reduces the number of parameters to be transmitted. This maintains scheduling decision accuracy for allocated resources while significantly reducing uplink control transmission time.
Data Source
AI summary
A communications system of the present invention is an OFDMA system (100) including a base station (10) and mobile stations (20), the base station (10) communicating wirelessly with the mobile stations (20) over a plurality of channels. Each mobile station (20) includes: a reception quality measuring section (19) for measuring reception quality; and a reception quality information determining section (12) for generating reception quality information only for each subgroup that belongs to the group(s) allocated to that mobile station (20) to report, (i) by 2-step grouping scheme information by which the channels are divided into subgroups, the subgroups are divided into groups, and the groups are allocated to the mobile stations (20) and (ii) according to the reception quality measured by the reception quality measuring section (19). The base station (10) schedules wireless communications over the channels according to the reported reception quality information. Accordingly, the amount of the reception quality information sent from the terminals to the base station is reduced to improve throughput.