Relay Node Codebook Selection for Quantization Overhead Reduction
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Solution Overview
Problem
In communication systems, the number of bits required to notify quantization parameters changes with reception quality, leading to increased signal overhead, as relay nodes need to transmit adapted quantization level values to receiving nodes, often requiring a large number of bits for each notification.
Innovation Solution
A communication system where relay nodes estimate the reception SNR, select a code book number based on this value, and transmit only the code book number along with the likelihood quantization bit value, using a pre-calculated quantization code book to reduce the number of bits needed for parameter notification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay nodes transmit adapted quantization level values to receiving nodes, then communication quality is improved, but the number of bits required for parameter notification increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple quantization level values corresponding to different reception quality conditions in a codebook at the relay node. Instead of calculating and transmitting the actual quantization parameter in real-time, the relay node selects a codebook index that corresponds to the current reception quality condition and transmits only this index. The receiving node uses the same codebook to retrieve the appropriate quantization level value. This approach significantly reduces the number of bits required for parameter notification while maintaining the ability to adapt to changing communication conditions.
2Productivity
If quantization parameters are adaptively changed according to probability distribution of detected likelihood, then likelihood quantization bits are reduced, but signal overhead increases due to parameter notification
Solution Approach 1:
The patent applies the copying principle by having both the relay node and receiving node store identical codebooks containing the same set of pre-calculated quantization level values. The relay node transmits only a codebook index (a copy reference) rather than the actual quantization parameter data. The receiving node uses its local copy of the codebook to retrieve the correct quantization level value corresponding to the transmitted index. This eliminates the need to transmit lengthy quantization parameter data while maintaining adaptive quantization capabilities.
Data Source
AI summary
A relay apparatus includes: an estimation unit selects a code book number corresponding to a reception SNR range based on an estimated reception SNR value; a soft demodulation unit that performs soft demodulation on a received first signal to detect a likelihood of the received first signal; a first memory unit that stores a first quantization code book showing, for each code book number, a relationship between a quantization parameter and a likelihood quantization bit value; a quantization unit that refers the first quantization code book to obtain a relationship between a quantization parameter and a likelihood quantization bit value that corresponds to the selected code book number, and adaptively quantizes the detected likelihood by using the obtained relationship to obtain a likelihood quantization bit value; and a transmission unit that transmits, to the receiving apparatus, a second signal including the obtained likelihood quantization bit value and the selected code book number.