An efficient random access scheme for OFDMA systems with implicit message transmission

作者：Zhou Ping^*; Hu Honglin; Wang Haifeng; Chen Hsiao Hwa

来源：IEEE Transactions on Wireless Communications, 2008, 7(7): 2790-2797.

DOI：10.1109/TWC.2008.070173

• multiple access
• random access channel
• resource management
• OFDMA
• throughput
• access delay

Random access channel (RACH) is usually used for initial channel access, bandwidth request, etc. In this paper, we analyze the throughput and access delay performance of the RACH in an orthogonal frequency division multiple access (OFDMA) system. A closed-form expression of the RACH throughput is presented and its mean access delays under both binary exponential and uniform backoff policies have also been derived. Moreover, to further improve the utilization of RACH in an OFDMA system, we propose a novel message transmission scheme in a shared RACH. The message in the proposed scheme can be sent implicitly in the cyclic-shifted preambles which make the transmission much more reliable in a contention based RACH. Meanwhile, performance of the preamble detection has also been improved by the redundant information conveyed in messages. Finally, simulation results will demonstrate performance gains of the proposed scheme.

• 出版日期2008-7
• 单位上海无线通信研究中心