Performance Evaluation of Hybrid-Multicarrier Access Schemes for Broadband Wireless Communication

Nirmalendu Bikas Sinha ； Sourav Chakraborty

《Research Journal of Applied Sciences, Engineering and Technology》 2卷6期 (2010/09) Pp. 519-526

並列摘要

The realization of wireless communication providing high speed, high capacity and high quality information exchange between two portable terminals that might be located anywhere in the world is still the communication challenge. For the development of future wireless communication systems, an extremely spectrum-efficient transmission technology is required. In this study authors propose a novel signal scheme called Hybrid CDMA-SFH which combines OFDM with CDMA and SFH to generate a system functionally superior to MC-CDMA systems. This study explores various merits and demerits of the proposed system and compares it to the other multicarrier access schemes. The CDMA component provides the inherent advantage of DS-CDMA systems incorporating a spreading signal based on PN code sequence, by providing user discrimination based on coding at the same carrier frequency and simultaneously. The OFDM component provides resistance to multipath effects making it unnecessary to use RAKE receivers for CDMA and thus avoid hardware complexity. The SFH component provides resistance to the ＂near-far＂ problem inherent in CDMA. Therefore, this system retains the greatest advantage of CDMA viz., multiple accesses without the disadvantages of ＂near-far＂ problems and complexity of RAKE receivers. Hence authors should look for OFDM because of its robustness to multipath and sophistication of synchronisation and because of the possibility of using coherent signal processing in spite of frequency hopping and at the same time the multiuser capability of CDMA systems. This is the novelty of our proposal. The simulated results elucidate that a significant amelioration in terms of utilities specifically spectral efficiency for all users can be achieved using this approach. A lso the propounded scheme exhibits better performance in the Hybrid CDMA-SFH in terms of spectral efficiency as compared to the traditional system.

並列關鍵字

CDMA ； Hybrid CDMA-SFH ； MIMO-CDMA ； RAKE