Wireless Receiver Modulo Estimation via Channel State Comparison
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Solution Overview
Problem
In wireless communication systems, terminal devices need to determine whether modulo calculations are required for received signals to differentiate between nonlinear and linear precoding, but relying on control information increases overhead, limiting frequency efficiency.
Innovation Solution
A wireless receiving apparatus that uses channel state information to estimate whether modulo calculations are necessary by comparing channel estimation values obtained through different precoding methods, allowing it to demodulate signals without receiving control information from the transmitting apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control information is supplied to indicate whether modulo calculations are required, then the terminal device can correctly differentiate between nonlinear and linear precoding, but the overhead increases, limiting frequency efficiency
Solution Approach 1:
The terminal device performs self-determination of the precoding method by independently calculating first channel state information from reference signals and second channel state information from data signals, then comparing these values to determine whether nonlinear precoding is used. This self-service mechanism eliminates the need for overhead control information from the base station while ensuring accurate precoding differentiation.
Solution Approach 2:
The terminal device uses feedback from its own reception measurements by comparing channel state information derived from different signal types (reference vs. data signals). This internal feedback loop enables the terminal to autonomously detect the precoding method without external control information, resolving the contradiction between reliability and frequency efficiency.
2Loss of energy
If nonlinear precoding is used to reduce transmission power, then frequency efficiency is improved, but modulo loss may occur, potentially decreasing transmission performance compared to linear precoding
Solution Approach 1:
The system dynamically adapts between linear and nonlinear precoding methods based on channel conditions. The terminal device determines the actual precoding method used by the base station through comparison of channel state information, and accordingly switches between linear processing and nonlinear processing with modulo operations. This dynamic adaptation allows the system to exploit the transmission power reduction benefit of nonlinear precoding when channel conditions are favorable, while avoiding modulo loss by using linear precoding when conditions are unfavorable, thus optimizing both energy efficiency and transmission reliability.
Data Source
AI summary
A data signal component output from a reference signal demultiplexer and channel state information obtained by using DM-RS output from a channel estimating unit are input into a modulo estimating unit. In a channel compensator, a first provisional decision value sequence is calculated on the basis of the channel state information. The first provisional decision value sequence is input into a modulo calculator, and modulo calculations are performed on the first provisional decision value sequence to obtain a second provisional decision value sequence. A decision-feedback channel estimating section finds a first channel estimation value based on the first provisional decision value sequence and a second channel estimation value based on the second provisional decision value sequence. A modulo decision section decides whether or not a perturbation term has been added to a code, and uses a decision result for the selection of a demodulation method.