Design and implementation of multi-band pulsed-OFDM system for wireless personal area networks
We study the theory and implementation of pulsed orthogonal frequency division multiplexing (pulsed-OFDM) modulation. Pulsed-OFDM is an enhancement to the leading proposal to the IEEE 802.15.3a wireless personal area networks standardization effort, known as multi-band OFDM. In particular, we show in this paper that the pulsed-OFDM system has better performance than the non-pulsed system in indoor multipath channels and considerably lower complexity and power consumption. We begin by studying the, spectral characteristics of pulsed OFDM and the added degrees of diversity that it provides. Next, we discuss the design of receivers for such a system. We show that the diversity branches can be captured and demodulated by one or more fast Fourier transform (FFT). We then focus on a system for the IEEE 802.15.3a standard and derive a particularly low complexity implementation for that system. The implementation is based on carefully designed punctured convolutional codes. It also exploits the normal inefficiencies in an FFT architecture to implement the parallel FFT operations required to demodulate a full diversity pulsed OFDM with lower complexity and smaller area than the single FFT used by the non-pulsed system. We conclude by presenting realistic simulation results for the measured indoor propagation channels provided by the IEEE 802.15.3a standard.