This paper investigates the effects of asynchronous multiple access interference (MAI) on the performance of orthogonal frequency-division multiple access (OFDMA) uplink systems in frequency-selective Rayleigh fading environments. We first analyze the MAI and its statistical characteristics using the Gaussian approximation. Then the analytical expression for the uncoded average symbol error probability (SEP) is obtained with various modulation schemes. Comparison with simulation results shows a tight agreement of the proposed analysis over a wide range of asynchronous timing errors and for various numbers of asynchronous users. Numerical examples show that when asynchronous timing errors reside within the guard interval, a performance of uncoded SEP- 10-3 can be feasible even in high dispersive environments. Furthermore, the effect of the Gaussian approximation is examined, and the performance comparison between interleaved- and block-type subcarrier allocation schemes is provided.
Bibliographical noteFunding Information:
This research was supported by the MKE (Ministry of Knowledge Economy), Korea, under the ITRC (Information Technology Research Center) support program supervised by the IITA (Institute for Information Technology Advancement) (IITA-2009-(C1090-0902-0011)), and in part by the Korea Science and Engineering Foundation through the NRL Program (Grant R0A-2007-000-20043-0).
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering