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A Random Access Scheme Robust to Timing Offsets for Uplink OFDMA Systems  

Song, Hyun-Joo (동국대학교 정보통신공학과)
Rim, Dae-Woon (동국대학교 정보통신공학과)
Jeong, Byung-Jang (한국전자통신원)
Noh, Tae-Gyun (한국전자통신원)
Rim, Min-Joong (동국대학교 정보통신공학과)
Publication Information
The Journal of Korean Institute of Communications and Information Sciences / v.33, no.6A, 2008 , pp. 659-665 More about this Journal
Abstract
If ranging processes are not frequent in an uplink OFDMA system, the timing synchronization between base and mobile stations may not be maintained. Especially in the case of infrequent random accesses in a large cell, timing offsets can be considerable and the destroyed orthogonality of OFDMA signals may result in the degraded performance. This paper proposes a novel random access scheme for uplink OFDMA systems, which support the orthogonality of OFDMA signals with timing offsets by allowing a random access OFDMA symbol shorter than a normal one. In order to make uplink OFDMA systems robust to timing offsets, the proposed scheme inserts a zero-padding region in an OFDMA symbol.
Keywords
Random Access; OFDMA; Uplink; Timing Offset; Zero-Padding;
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  • Reference
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