1. Precoded Multiuser OFDM Transceiver in Timing Asynchronous Environment.
- Author
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Shang-Ho Tsai, Yuan-Pei Lin, and Kuo, C.-C. Jay
- Subjects
- *
DATA transmission systems , *MULTIPLEXING , *RADIO transmitter-receivers , *CODING theory , *INFORMATION theory , *SIGNAL processing - Abstract
The performance of a multiuser orthogonal frequency-division multiplexing (OFDM) transceiver, called the precoded multiuser OFDM (PMU-OFDM), with time asynchronous access is investigated in this paper. It is shown that multiaccess interference (MAI) due to time asynchronism is asymptotically zero as the number of parallel input symbols N becomes large in the PMU-OFDM system. Then, we show that PMU-OFDM with even or odd Hadamard—Walsh codewords can significantly suppress the MAI effect due to time asynchronism. For the half-loaded case, no sophisticated signal processing technique is needed by PMU-OFDM for MAI suppression. For the fully loaded situation, PMU-OFDM demands less complexity than does conventional OFDMA for interference suppression since PMU-OFDM deals with only one half of interferers. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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