Dynamic Zero Suffix Addition for OFDM Signal Processing
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Solution Overview
Problem
In MB-OFDM systems, the addition of a zero suffix to received signals to combat multipath issues introduces noise, especially in channels with minimal multipath, such as AWGN channels, where the added suffix provides no benefit and degrades system performance.
Innovation Solution
A method to determine and add only the necessary number of zero suffix samples to the received signal, based on analyzing the energy distribution from synchronization symbols, to maintain orthogonality between subcarriers while minimizing noise introduction, by correlating and selecting samples that likely contain information bearing portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire zero suffix is added to the received signal to accommodate worst case multipath, then all multipath energy is captured and orthogonality is maintained, but noise is added to the summed signal in channels with minimal multipath
Solution Approach 1:
Instead of adding the entire zero suffix (excessive action), the patent applies partial action by adding only a portion of the zero suffix. The system determines the actual multipath delay spread and adds only the necessary portion of the zero suffix to accommodate the actual channel conditions, avoiding unnecessary noise addition in channels with minimal multipath while still capturing all multipath energy when present.
2Ease of manufacture
If a fixed zero suffix length is used for all channels, then the implementation is simple, but performance degrades in channels with minimal multipath
Solution Approach 1:
The patent transitions from a fixed zero suffix length to a dynamic approach. The system estimates the multipath delay spread from the received signal and dynamically determines the appropriate zero suffix length to add. This dynamic adjustment optimizes system performance across different channel conditions while maintaining implementation simplicity through automated estimation and adaptation.
Data Source
AI summary
A method of processing a received OFDM symbol is disclosed. The received OFDM symbol has a symbol portion and a zero suffix portion. An information bearing portion of the zero suffix portion that is likely to contain information is determined and is combined with the symbol portion.