In this paper, we apply recently developed energy spreading transform (EST) technique to down-link MC-CDMA systems for frequency and spatial diversity. The performance of the proposed EST based MC-CDMA systems is independent of the number of active users, which is different from all current MC-CDMA systems. It is demonstrated by computer simulation that the BER for the EST based system is 1.1 × 10-4 while it is 1.6 × 10-3 for a MC-CDMA system without EST when the system is with full load and E b/No = 12 dB. The EST based MC-CDMA system also facilitates transmit diversity and MIMO techniques when multiple transmit and receive antennas are available. In particular, we develop symbol shuffle and combined schemes for spatial diversity for a EST based MC-CDMA system with multiple transmit antennas at the base station. Compared with a MC-CDMA system without EST, the required Eb/No for 1% BER for the developed scheme is improved by about 4 dB.
Bibliographical noteFunding Information:
Manuscript received December 21, 2006; revised February 22, 2007; accepted February 23, 2007. The associate editor coordinating the review of this paper and approving it for publication was C. Xiao. The work was supported by the research contract 46133697 between France Telecom and YGL Telecomm Lab, Inc.
All Science Journal Classification (ASJC) codes
- Computer Science Applications
- Electrical and Electronic Engineering
- Applied Mathematics