Downlink Precoding Feedback Using Valid Orthogonal Bases
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Solution Overview
Problem
In wireless communications systems with partial channel reciprocity, existing methods fail to optimize downlink precoding effectively due to inefficiencies in feedback mechanisms, particularly in frequency division duplex (FDD) systems where uplink and downlink channels have partial angular and delay domain reciprocity, leading to suboptimal channel capacity.
Innovation Solution
A method where a terminal sends information for determining the position and coefficient of valid orthogonal bases to a network side, allowing the network side to reconstruct downlink precoding, thereby optimizing the correspondence between orthogonal bases and ports, reducing feedback overheads and enhancing channel capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal sends detailed channel state information for downlink precoding optimization, then the downlink transmission performance is improved, but the feedback overhead increases significantly
Solution Approach 1:
The patent extracts only the essential information needed for downlink precoding optimization - specifically the position and coefficient information of valid orthogonal bases - rather than transmitting complete channel state information. This selective extraction maintains transmission performance while significantly reducing feedback overhead.
Solution Approach 2:
The patent applies partial action by transmitting only sufficient information (position and coefficients of orthogonal bases) rather than complete channel state information. This partial information is enough for the network side to reconstruct precoding matrices, achieving good enough performance with reduced overhead.
2Device complexity
If the network side uses only angular domain reciprocity for precoding design in partial reciprocity scenarios, then the system complexity is reduced, but the channel capacity is limited
Solution Approach 1:
The patent extends the precoding optimization from only angular domain to include delay domain by introducing orthogonal bases in delay domain. This dimensional extension allows the system to exploit both angular and delay reciprocity, increasing channel capacity while maintaining manageable complexity through structured basis representation.
Solution Approach 2:
The patent changes the approach from using only angular parameters to incorporating delay domain parameters through orthogonal bases. By transforming the problem into the delay domain and using orthogonal basis representation, the system can exploit partial reciprocity more effectively to improve channel capacity.
Data Source
AI summary
A transmission method and apparatus, a device, and a readable storage medium are disclosed. The method includes: sending, by a terminal, information for determining a position of a valid orthogonal basis and a coefficient of the valid orthogonal basis to a network side.