Bit error rate performance evaluation of an ultra wide band communication system with dual carrier modulation and space diversity

Abstract

Dual carrier modulation (DCM) is taken as a global standard for ultra wide band (UWB) wireless communication system in establishing wireless personal area network (WPAN) such as wireless universal serial bus (W-USB) and wireless high definition media interface (WHDMI), where a data rate of ≥320 Mbps is desired. In practice, DCM transforms 2 Quadrature Phase Shift Keying (QPSK) symbols into two 16 Quadrature Amplitude Modulation (16QAM) like DCM symbols using DCM matrix. Constellation rearrangement (CoRe) is an inherent part of DCM and thereby DCM achieves coding gain by constellation rearrangement (CoRe) and diversity gain by symbol repetition.

A number of researches are carried out on the BER performance of a DCM MB-OFDM in an UWB wireless communication system but without space diversity. In these works, the authors claim that DCM provides a considerable amount of BER reduction in comparison to QPSK and improves the overall data handling capacity in short range wireless communication. In view of the success of space diversity in reducing BER in numerous wireless communication studies, it is envisaged that incorporation of space diversity with DCM may further reduce the BER at the receiver and thereby enhance the overall performance of a system. Hence, an analytical approach is adopted to evaluate the BER performance of DCM MB-OFDM UWB system with space diversity over a Rayleigh fading channel.

Analytical expression for BER is deduced and evaluated through numerical computation where, the graphical results are compared with the previous works to validate its effectiveness. Analyzing the results, it is found that with the increment of number of receiving antenna, receiver sensitivity increases and the overall performance improves. However, using multiple transmitting antennas without incorporating any transmission diversity coding technique causes performance deterioration. Therefore, in a DCM system, the number of transmitting antenna should not be more than that of the receiving antenna in absence of transmission diversity coding technique. The outcome of the research is expected to open a new horizon in the arena of DCM to carry out further research in quest of enhancing the performance of a DCM UWB wireless communication system in future.