Performance Study of Discrete Wavelet Packet Based MB-OFDM System for Short Range Indoor Wireless Environment

Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) approach using UWB signals with short duration of pulses provide unique advantages in short-range high data rate wireless applications which include easy penetration through obstacles, high precision ranging and low processing power. A perfect reconstruction using discrete wavelet packet transmultiplexer in MB-OFDM transceiver counters the degrading effect of ISI, and also conserves bandwidth. In comparison to conventional FFT MB-OFDM, Discrete Wavelet Packet Modulation (DWPM) offers much lower side lobes in the transmitted signal, which reduces inter carrier interference (ICI) and narrowband interference (NBI). In this paper a detail study on conventional MB-OFDM and Discrete Wavelet Packet Transform (DWPT) MB-OFDM is attempted for high data rate ultra wideband (UWB) WPAN physical layer standard. Different multipath components in the UWB channels are characterized by different delays and attenuation. BER performances of MB-OFDM UWB on IEEE 802.15.3a channel models are investigated through simulation study. We show that, at low data rate (55 Mbps) the DWPT MB-OFDM system performs better in the CM4 channel environment than in the CM3 channel due to its inherent frequency diversity. In high data rate (480 Mbps), the BER performance in CM3 channel model is found to be better than in CM4 channel model. DWPT MB-OFDM outperforms than the conventional FFT MB-OFDM for high data rate applications.