Multiple-access schemes for IEEE802.15.4a

Abstract

Ultra wideband (UWB) impulse radio (IR) is a prospective transmission technology for low-rate indoor communications, as described in the physical layer proposals for IEEE 802.15.4a wireless personal area networks (WPAN). Time hopping (TH) is considered as an access scheme for multi-user UWB-IR systems. Communication over the indoor wireless channel is a technical challenge, not only because it is varies from place to place, but also because the signal suffers from heavy multi-path propagation. The motivation to search for improved modulation schemes is to improve the performance of data transmission, reduce the Bit Error Rate (BER) and increase the multiple-access capacity. In this project, two modulation schemes, namely, time hopping-binary phase shift keying (TH-BPSK) and time hopping-pulse position modulation (TH-PPM) were studied. Simulation is done using MatLab to verify that the performance is closed to theoretical value and TH-BPSK outperforms TH-PPM. The influence of different combinations of TH processing gains, multipaths and multi-users on BER performance of the two schemes is analysed and numerical results are presented for illustration.