Received Power Codebook for Distributed Antenna CSI Feedback
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Solution Overview
Problem
In wireless communication systems, particularly in distributed antenna systems, the existing codebook-based precoding methods face challenges due to power differences caused by path losses between antennas, leading to increased feedback overhead and reduced uplink performance when trying to account for these differences.
Innovation Solution
The introduction of a received power codebook and a corresponding feedback mechanism allows for the quantization of relative received power values, enabling the UE and base station to determine optimal precoding codebook elements, reducing feedback overhead and improving system performance by accounting for antenna power variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the codebook is designed to account for power differences caused by path losses in distributed antenna systems, then the system performance is improved, but the codebook size becomes very large, increasing feedback overhead and sacrificing uplink performance
Solution Approach 1:
The codebook is segmented into multiple sub-codebooks, each corresponding to a specific antenna port. Instead of using one large codebook to cover all possible antenna combinations, the system divides the codebook into smaller pieces that can be independently selected and combined, reducing the overall feedback overhead while maintaining the ability to account for power differences across distributed antennas
Solution Approach 2:
The patent introduces a new dimension to the codebook structure by adding antenna port indication information to the existing precoding matrix index. This creates a two-dimensional codebook structure where one dimension represents the precoding matrix selection and the other represents the antenna port selection, allowing the system to handle distributed antenna scenarios without exponentially increasing the codebook size
2Reliability
If the codebook size is increased to account for power differences and path losses, then downlink performance is improved, but uplink performance is sacrificed due to increased feedback overhead
Solution Approach 1:
The patent extracts the antenna port indication information from the traditional single codebook and separates it into a distinct component. This extraction allows the system to independently optimize the precoding matrix selection and antenna port selection, reducing the feedback overhead required for uplink while maintaining the ability to optimize downlink performance through coordinated selection of both components
3Adaptability or versatility
If a large codebook is used to cover all antenna combinations in distributed antenna systems, then the system can handle power variations, but the device complexity and codebook management become more difficult
Solution Approach 1:
The patent performs preliminary action by pre-defining multiple sub-codebooks for different antenna ports before the actual communication occurs. Each sub-codebook is pre-optimized for specific antenna configurations, allowing the system to quickly select the appropriate sub-codebook and precoding matrix without performing complex real-time calculations, thus reducing device complexity while maintaining adaptability to power variations
Data Source
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AI summary
Embodiments of the present invention provide a method, device, and system for sending channel state information. The method for sending channel state information includes: setting number of bits used for quantizing a relative received power value; sending the number of bits to a user equipment UE; receiving a received power codebook index value; determining a received power codebook element corresponding to the received power codebook index value; and processing a signal according to the corresponding received power codebook element. Another method for sending channel state information includes: receiving the number of bits used for quantizing a relative received power value; selecting a received power codebook index value from multiple received power codebook index values; and sending the selected received power codebook index value to a base station. The above solutions can reduce a feedback overhead, improve a CSI feedback effect, realize antenna selection, and further improve overall system performance, and further are capable of multiplexing the precoding codebook of the existing centralized antenna system, thereby reducing complexity of the system.