Accurate Evaluation of Multiple-Access Performance in TH-PPM and TH-BPSK UWB Systems

Abstract

Abstract-A characteristic function method is proposed for precisely calculating the bit-error probability of time-hopping (TH) ultra-wideband (UWB) systems with multiple-access interference in an additive white Gaussian noise environment. The analytical expressions are validated by simulation and used to assess the accuracy of the Gaussian approximation. The Gaussian approximation is shown to be inaccurate for predicting bit-error rates (BERs) for medium and large signal-to-noise ratio (SNR) values. The performances of TH pulse position modulation (PPM) and binary phaseshift keying (BPSK) modulation schemes are accurately compared in terms of the BER. It is shown that the BPSK system outperforms the binary PPM system for all values of SNR. The sensitivity of the performance of the modulation schemes to the system parameters is also addressed through numerical examples.

Th-Uwb Receiver Based on Two PDFS Approximation in Multiuser Systems

“…When the pulse of the desired user in the mth frame is not collided, we use f a Y m (y m ) to model the distribution of the total disturbance in this frame, and then the log-likelihood ratio in the mth frame is calculated according to (11). When the pulse of the desired user in the mth frame is collided, we use f b Y m (y m ) to model the distribution of the total disturbance in this frame, and the log-likelihood ratio in the mth frame can be obtained accordingly.…”

“…It has been shown that in TH-UWB multiuser systems the bit error rate (BER) performance of the conventional matched filter (CMF) receiver, the optimal receiver when only additive Gaussian noise is presented in the channel, is significantly degraded by the multiuser interference [10]. The CMF receiver is no longer the optimal receiver for TH-UWB systems because the multiuser interference plus noise, which will be referred to as total disturbance hereafter, is not reliably Gaussian distributed [11].…”

Analytical Approach for the TH-BPSK Ultra-Wideband Systems Performance

“…Analysis of TH-BPSK UWB systems was analyzed and studied in [6], [7], [8]. In [9], a performance comparison between different modulation schemes was applied.…”

Packet collision based Multiuser Interference (MUI) analysis for TH-PAM and TH-PPM ultra wideband (UWB) system

“…For multiple access in Impulse radio based UWB system, literatures [3], [6] suggest method based on Time Hopping (TH) technique. This access technique can be used with Pulse Position Modulation (PPM) or Pulse Amplitude Modulation (PAM) schemes.…”

“…This access technique can be used with Pulse Position Modulation (PPM) or Pulse Amplitude Modulation (PAM) schemes. Depending upon modulation scheme TH UWB signal is known as TH-PAM UWB [3] or TH-PPM UWB [3], [6]. Also Direct Sequence UWB (DS-UWB) approach proposed in [7] which is same as TH-PAM UWB except minor difference.…”