OFDM Receiving Device Norm-Based Weighting for Noise Resilience
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power line communication receiving devices face challenges in maintaining decoding performance due to noise interference and increased processing complexity when using known signals for normalization and weighting in OFDM systems, leading to reduced throughput and increased noise-induced incorrect weighting.
Innovation Solution
A receiving device that applies an FFT process to obtain subcarrier signals, calculates the norm of these signals, generates a weighting factor based on statistical variations, and uses this factor to weight the bit strings, eliminating the need for reference symbol points and reducing processing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known signals (preamble, pilot) are used for normalization and weighting of subcarrier signals, then decoding performance is maintained, but processing complexity increases and throughput decreases
Solution Approach 1:
The invention extracts only the necessary information (norm statistics) from the received OFDM symbol without requiring separate known signals. By calculating the norm of each subcarrier signal and using its statistical properties directly, the system eliminates the need for preamble and pilot signals while maintaining decoding performance.
Solution Approach 2:
The norm calculation serves multiple functions simultaneously: it provides channel normalization information, enables weighting factor generation, and supplies soft decision values for decoding. This multi-functionality replaces the separate roles previously fulfilled by known signals and normalization processes.
2Measurement precision
If weighting is performed by received power of each subcarrier using known signals, then decoding accuracy is improved, but noise-induced incorrect weighting increases
Solution Approach 1:
The invention uses feedback from the norm statistics of the received signal itself to generate weighting factors. By calculating the norm of each subcarrier and using its statistical properties (mean and variance) as feedback, the system adapts the weighting to actual channel conditions without being misled by noise, since the statistics are derived from multiple symbols.
Solution Approach 2:
The system performs preliminary calculation of norm statistics over multiple OFDM symbols before generating weighting factors. This preliminary action allows the system to establish accurate statistical baselines that are resistant to temporary noise fluctuations, ensuring more reliable weighting decisions.
3Reliability
If normalization and weighting are based on subcarrier power using known signals, then frequency selective fading is compensated, but the number of processes increases
Solution Approach 1:
The invention merges the normalization and weighting operations into a single process based on norm statistics. Instead of separate normalization using known signals and subsequent weighting, the system combines these functions by directly using the norm statistics of data symbols to generate both normalization and weighting information in one step.
Solution Approach 2:
The received OFDM symbols themselves provide the information needed for normalization and weighting through their norm statistics. The system serves itself by using the inherent properties of the received signal (norm values) rather than requiring external reference signals, thereby eliminating redundant processing steps.
Data Source
AI summary
A receiving device according to the present invention includes: a receiver for receiving an OFDM symbol that is modulated by phase shift keying; an FFT processor for applying an FFT process to the received OFDM symbol to obtain a subcarrier signal; a demapping unit for demapping the subcarrier signal to generate a bit string; a norm calculator for calculating the norm of the subcarrier; a weighting factor generator for generating a weighting factor by taking the statistics of the calculated norm; and a weighting unit for obtaining a soft decision value by weighting the bit string after demapping, based on the particular weighting factor. Thus, the receiving device can obtain a soft decision value to achieve good decoding performance with a small number of known signals and processes.