Performance of a TH-PPM UWB System in Different Scenarios Environments

Ultra Wideband (UWB) communication technology has attracted considerable attention by researchers in recent years because of its appealing features and its several applications it offers in many areas (Win & Scholtz, 1998; Fontana, 2007; Ghavami et al, 2007). An UWB system is characterised by very short-duration pulses (usually on the order of a nanosecond) with a low duty cycle. It offers low power transmission, a fine path resolution and it easily supports multi-user communication (Di Benedetto, 2004). These properties make UWB technology an attractive candidate for short-range, high-speed wireless multiple access communication and ad hoc networking, with simple baseband and the capability to overlay legacy wireless systems. All this gives us many features such as wireless radar, communications, networking, imaging and positioning systems (Yang & Giannakis, 2004). Historically, UWB systems are based on impulse radio (IR) concepts. In an IR UWB system, a number of pulses are transmitted per information symbol and information is usually conveyed by the positions or the polarities of the pulses. In order that impulse radios, operating in the highly frequency range below a few GHz, do not interfere with narrowband radio systems operating in the same frequency band, the use of spread-spectrum techniques is necessary. A simple mean to spread the spectrum of these UWB pulse trains is Time Hopping (TH), with data modulation achieved in the rate of many pulses per data symbol (Win & Scholtz, 1998, a). In UWB systems, there are several basic methods of modulation but the most common impulse radio based UWB concepts are based on Pulse Position Modulation combined with Time Hopping (TH-PPM) where each pulse is delayed in advance of a regular time scale. Thereafter, we will describe this concept with further details. The study of digital communications system performance over the AWGN (Additive White Gaussian Noise) channels starts generally with statistically independent zero-mean Gaussian noise samples. Due to the Gaussian statistics of the noise samples, the probability of error can therefore be written in terms of a Q-function. There exists a set of efficient techniques for performance analysis when the system is distorted by AWGN and Rayleigh fading. We shall focus on the analytical methods that are useful in addressing the characteristics unique to UWB systems, such as the different modulation schemes and the large number of resolvable paths available to the receiver. In a UWB system rather realistic, the received pulses may overlap others causing inter-pulse 4

[1]  Ridha Bouallegue,et al.  Performance of TH-PPM ultra wideband systems in multi-user environments , 2009, 2009 6th International Multi-Conference on Systems, Signals and Devices.

[2]  Moe Z. Win,et al.  Ultra-wide bandwidth time-hopping spread-spectrum impulse radio for wireless multiple-access communications , 2000, IEEE Trans. Commun..

[3]  G. Durisi,et al.  On the validity of Gaussian approximation to characterize the multiuser capacity of UWB TH PPM , 2002, 2002 IEEE Conference on Ultra Wideband Systems and Technologies (IEEE Cat. No.02EX580).

[4]  Sergio Benedetto,et al.  Performance evaluation of TH-PPM UWB systems in the presence of multiuser interference , 2003, IEEE Communications Letters.

[5]  Georgios B. Giannakis,et al.  Ultra-wideband communications: an idea whose time has come , 2004, IEEE Signal Processing Magazine.

[6]  Ridha Bouallegue,et al.  Performance of a TH-PPM Ultra Wideband System in Different Scenarios Environments , 2009 .

[7]  R. Stanley,et al.  Preliminary results of an ultra-wideband (impulse) scanning receiver , 1999, MILCOM 1999. IEEE Military Communications. Conference Proceedings (Cat. No.99CH36341).

[8]  Matti Latva-aho,et al.  On the UWB system coexistence with GSM900, UMTS/WCDMA, and GPS , 2002, IEEE J. Sel. Areas Commun..

[9]  Huaping Liu,et al.  On the optimum linear receiver for impulse radio systems in the presence of pulse overlapping , 2005, IEEE Communications Letters.

[10]  Bo Hu,et al.  Exact bit error rate analysis of TH-PPM UWB systems in the presence of multiple-access interference , 2003, IEEE Communications Letters.

[11]  Guerino Giancola,et al.  Understanding Ultra Wide Band Radio Fundamentals , 2004 .

[12]  Moe Z. Win,et al.  On the robustness of ultra-wide bandwidth signals in dense multipath environments , 1998, IEEE Communications Letters.

[13]  Moe Z. Win,et al.  Impulse radio: how it works , 1998, IEEE Communications Letters.

[14]  Li Zhao,et al.  Multi-user capacity of M-ary PPM ultra-wideband communications , 2002, 2002 IEEE Conference on Ultra Wideband Systems and Technologies (IEEE Cat. No.02EX580).

[15]  Ridha Bouallegue,et al.  Performance of TH-PPM ultra wideband systems in multipath environments , 2009, 2009 International Conference on Telecommunications.

[16]  Robert A. Scholtz,et al.  Multiple access with time-hopping impulse modulation , 1993, Proceedings of MILCOM '93 - IEEE Military Communications Conference.

[17]  Ridha Bouallegue,et al.  Study of different pulse waveforms and performance of TH-PPM Ultra Wideband Systems in multipath and multi-user environments simultaneously , 2009, 2009 16th IEEE International Conference on Electronics, Circuits and Systems - (ICECS 2009).

[18]  Ridha Bouallegue,et al.  Analytical probability of error in TH-PPM and TH-PAM ultra wideband systems , 2008, 2008 15th IEEE International Conference on Electronics, Circuits and Systems.

[19]  Vivien Chu,et al.  Ultra Wideband Signals and Systems in Communication Engineering , 2007 .

[20]  Jeff Foerster,et al.  Ultra-Wideband Technology for Short- or Medium-Range Wireless Communications , 2001 .