Multi-User OFDM Detection via Combined Channel Response
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Solution Overview
Problem
In broadband wireless communication systems, the use of traditional single-carrier transmission approaches leads to significant InterSymbol Interference (ISI) and Multiple Access Interference due to non-orthogonal Repeat Codes sequences, which complicates signal demodulation and data separation in multi-user OFDM systems.
Innovation Solution
A method and device for multi-user detection in OFDM systems that combines received signals from repeated Block Units to form a data sequence, determines a combined repeated channel response sequence array, and uses this array to detect data symbols, effectively alleviating Multiple Access Interference and InterSymbol Interference by utilizing weight factors and scrambling codes to separate user signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Block Repeat transmission with non-orthogonal Repeat Codes is used to improve spectrum utilization and system capacity, then multiple users can share the same time and frequency resources, but Multiple Access Interference and InterSymbol Interference increase significantly
Solution Approach 1:
The patent combines signals from multiple repeated Block Units corresponding to the same data symbol into a single received data sequence. By merging these signals and determining a combined repeated channel response sequence array, the system effectively combines useful information from all users while suppressing Multiple Access Interference and InterSymbol Interference through joint detection.
Solution Approach 2:
The patent treats Multiple Access Interference and InterSymbol Interference as useful information by combining received signals from all repeated Block Units. Instead of treating interference as harmful noise to be eliminated, the system converts it into beneficial signal components that carry useful data information, thereby improving detection accuracy and system performance.
2Productivity
If Block Repeat transmission is used to increase system capacity and support more users, then more data can be transmitted simultaneously, but signal separation and demodulation become more complex
Solution Approach 1:
The patent segments the received signal into multiple repeated Block Units and processes each segment separately by combining signals at corresponding time and frequency symbol positions. This segmentation approach simplifies the overall demodulation process by breaking down the complex multi-user signal into manageable segments that can be processed using the combined repeated channel response sequence array.
3Ease of manufacture
If traditional single-carrier transmission is used to simplify system design, then implementation is easier, but InterSymbol Interference increases significantly in broadband wireless communication
Solution Approach 1:
The patent transforms the single-carrier transmission approach into a multi-carrier OFDM system with Block Repeat transmission. By changing the transmission parameters from single-carrier to multi-carrier with repeated blocks, the system effectively reduces InterSymbol Interference while maintaining manageable implementation complexity through the proposed joint detection method using combined repeated channel response sequences.
Data Source
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AI summary
Multi-users detecting method and device of OFDM transmission signal include that: a received data sequence is composed of the received signal which is in the position of the time and frequency symbol corresponding to the same data symbol in multi -repeating blocks; the composed repeating channel response sequence array which is corresponding to the received data sequence is determined; the received data sequence is detected to acquire the data symbol information of multi-users by using the composed repeating channel response sequence array. The technical solution can effectively restrain the multi-address interference and the interference between symbols during OFDM transmitting signal and improve the system performance greatly.