Simulation On BER Performance And Multi-Access Analysis Of UWB System

UWB is a new wireless communication technique. The modulated pulse has sharp ascending and descending edges, so the bandwidth of UWB signal is in GHz level, and insensitive to channel fading. Its power spectral density is very low, so it is unlikely to be captured. UWB system has a low complexity, and can provide centimeter-level positioning. UWB technique is developing a good potential in the field of short-range wireless communication. It is one of the most popular issues. The system performance analyses are critical to the investigation of UWB technique.Firstly, this paper introduced the development of UWB, the technology characteristics and application prospect. Combining the modulation and multi-access manner, this paper presented three UWB systems: TH-PPM (Time Hopping Pulse Position Modulation), TH-PAM (Time Hopping Pulse Amplitude Modulation) and DS-PAM (Direct Sequence Pulse Amplitude Modulation). Then described UWB standard channel model (IEEE802.15.3a) and the RAKE receiver for multi-path channel.Secondly, this paper deduced the BER expression of low-speed single-user system in IEEE802.15.3a channel model with ARAKE receiver, and built the three systems with"Simulink". The pulse of UWB system was second derivation of Gauss function and the receiver was PRAKE or SRAKE. This paper simulated the three UWB systems with different channel mode (CM1-CM4), different RAKE fingers, and analyzed the results: BER Performance of TH-PAM system is better than TH-PPM; BER decreases with the SRAKE or PRAKE fingers increasing, and 8 fingers can satisfy the BER performance; the BER increases when channel mode changing from CM1 to CM4.Finally, this paper introduced multi-access UWB system model in detail, and made analyses by simulating: Influence on BER by different number of multi-users; Max number of users in the system with given BER and Eb /N0 .