Analysis of ISI for an IR UWB symbol-differential autocorrelation receiver

The interframe (IFI) and intersymbol interference (ISI) of a symbol-differential autocorrelation receiver (SD-ACR) for an impulse radio ultra wideband (IR UWB) system in a multipath channel is evaluated. The system can be modelled as a nonlinear filter with respect to the input data sequence. The filter's coefficients are random variables for which we derive an accurate statistical description up to the second moments. The analysis shows the presence of a bias term, that makes the optimum decision threshold different from zero. The results obtained in this paper provide a good understanding of the performance degradation due to ISI and IFI and they show the impact on system design. Analytical results, confirmed by simulations point out a new concept for the pulse positioning within the symbol interval, and the transmission of one pulse per symbol emerges as the optimum choice for the single user case. Simulated results for the noise-free ideal environment confirm the influence of the system parameters in terms of BER and provide a measure of the achievable bit rate as a function of the channel RMS delay spread.

[1]  Urbashi Mitra,et al.  On optimal data detection for UWB transmitted reference systems , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[2]  Craig K. Rushforth.  Transmitted-reference techniques for random or unknown channels , 1964, IEEE Trans. Inf. Theory.

[3]  Dennis Goeckel,et al.  Generalized transmitted-reference UWB systems , 2003, IEEE Conference on Ultra Wideband Systems and Technologies, 2003.

[4]  V. Srinivasa Somayazulu,et al.  A differential detector for an ultra-wideband communications system , 2002, Vehicular Technology Conference. IEEE 55th Vehicular Technology Conference. VTC Spring 2002 (Cat. No.02CH37367).

[5]  Klaus Witrisal,et al.  Equivalent system model of ISI in a frame-differential IR-UWB receiver , 2004, IEEE Global Telecommunications Conference, 2004. GLOBECOM '04..

[6]  Wayne E. Stark,et al.  Performance of ultra-wideband communications with suboptimal receivers in multipath channels , 2002, IEEE J. Sel. Areas Commun..

[7]  Quang Hieu Dang,et al.  Signal processing model for a transmit-reference UWB wireless communication system , 2003, IEEE Conference on Ultra Wideband Systems and Technologies, 2003.

[8]  R. Hoctor,et al.  Delay-hopped transmitted-reference RF communications , 2002, 2002 IEEE Conference on Ultra Wideband Systems and Technologies (IEEE Cat. No.02EX580).

[9]  K. Witrisal,et al.  Multiuser interference and inter-frame interference in UWB transmitted reference systems , 2004, 2004 International Workshop on Ultra Wideband Systems Joint with Conference on Ultra Wideband Systems and Technologies. Joint UWBST & IWUWBS 2004 (IEEE Cat. No.04EX812).

[10]  Gerard J. M. Janssen,et al.  Analysis and comparison of autocorrelation receivers for IR-UWB signals based on differential detection , 2004, 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[11]  Robert A. Scholtz,et al.  Ultra-wideband transmitted reference systems , 2005, IEEE Transactions on Vehicular Technology.