Feedback Data Transmission in Multiple Antenna Systems
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Solution Overview
Problem
In multiple antenna wireless communication systems, transmitting channel quality indicators (CQIs) and precoding matrix indicators (PMIs) across all subbands results in significant overhead, affecting the efficiency of radio resource scheduling.
Innovation Solution
A method is introduced to selectively transmit feedback data, including frequency selective and frequency flat PMIs, best band CQI, and whole band CQI, by selecting a subset of subbands and using a common codebook, thereby reducing the overhead while maintaining accurate CQI reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CQIs and PMIs for all subbands are transmitted to enable effective radio resource scheduling, then scheduling accuracy is improved, but transmission overhead increases significantly
Solution Approach 1:
The frequency band is divided into multiple subbands, and the invention selectively reports CQI and PMI for a subset of subbands rather than all subbands. This segmentation allows the system to transmit feedback data for only the most relevant frequency portions, reducing overall overhead while maintaining scheduling accuracy for critical subbands.
Solution Approach 2:
Instead of reporting CQI and PMI for all subbands (excessive action), the invention applies partial action by selecting and reporting only for a subset of subbands. This partial reporting approach reduces the quantity of feedback data transmitted while still providing sufficient information for effective radio resource scheduling decisions.
2Reliability
If feedback data for all subbands is transmitted, then channel quality assessment is improved, but radio resource scheduling efficiency deteriorates due to overhead
Solution Approach 1:
The invention extracts and transmits only the essential feedback information (CQI and PMI) for a selected subset of subbands rather than all subbands. By taking out only the necessary feedback data, the system maintains sufficient channel quality assessment capability while significantly improving radio resource scheduling efficiency through reduced overhead.
Solution Approach 2:
The invention applies partial action by transmitting feedback data for only a subset of subbands rather than all subbands. This partial approach maintains reliable channel quality assessment for the most important frequency regions while improving overall scheduling efficiency by reducing the volume of feedback data that must be processed.
3Quantity of substance
If a common codebook is used for frequency selective and frequency flat PMI, then feedback data compression is improved, but precision in indicating different precoding strategies may be reduced
Solution Approach 1:
The invention employs a common codebook that serves multiple functions: it can indicate both frequency selective PMI and frequency flat PMI, as well as support different precoding strategies. This multi-functional codebook reduces feedback data size by eliminating the need for separate codebooks while maintaining the ability to precisely indicate various precoding approaches through proper indexing.
Solution Approach 2:
The invention merges the codebooks for frequency selective and frequency flat PMI into a single common codebook. This combining approach reduces the total feedback data size by eliminating redundancy between separate codebooks while maintaining the precision needed to indicate different precoding strategies through a unified indexing structure.
Data Source
AI summary
A method of transmitting feedback data in a multiple antenna system comprises receiving a request message of feedback data on a downlink channel, the request message comprising uplink scheduling information, selecting a set of M (M≧1) subbands within a plurality of subbands, generating the feedback data, the feedback data comprising a frequency selective PMI (precoding matrix indicator), a frequency flat PMI, a best band CQI (channel quality indicator) and a whole band CQI, and transmitting the feedback data on a uplink channel allocated to the uplink scheduling information.