SINR analysis of BPSK UWB considering IPI and ICI in IEEE channel models and its application

Abstract

Closed-form expressions for the output signal-tointerference-plus-noise ratio (SINR) in ultra-wideband (UWB) receivers are derived for the IEEE channel models. Unlike results in the literature where only the inter-symbol and/or multipleaccess interferences are considered, the derivation in this paper also takes into account inter-path and inter-chip interferences. Effects of the spreading gain and the pulse duration on the output SINR are examined. As an application, the optimal integration interval that maximizes the output SINR for a transmitted reference UWB receiver is studied.Index Terms-Average power, integration interval, signal-tointerference-plus-noise ratio, ultra-wide bandwidth. I. INTRODUCTIONAmong the properties of the received ultra-wideband (UWB) signals, the output signal-to-noise ratio (SNR) or the output signal-to-interference-plus-noise ratio (SINR) determine the performances of UWB systems [1]. After the IEEE 802.15.SG3a study group released four UWB channel models in 2002 [2], many researchers have studied the output SNR or the output SINR based on these channel models. Closedform expressions for the average output SNR were derived for Rake receivers in [3], and different SNR estimators were proposed in [4]. A closed-form expression for the output SINR of a Rake receiver was derived based on a constant delay spacing instead of the multipath delay in [5], where the multiple-access interference (MAI) was considered but other interferences, such as the inter-path interference (IPI), the inter-chip interference (ICI) and the inter-symbol interference (ISI), were ignored. In [6], the SINR of a Rake receiver was analyzed by taking both ISI and MAI into account.Whilst the aforementioned works give analytical expressions to estimate the SNR or the SINR for UWB systems, to the best of the authors' knowledge, none of these works has taken into account all the necessary interferences in the channel. Due to the extremely large bandwidth of a UWB system, in addition to MAI and ISI, IPI and ICI may also occur in the systems and have significant effects on the SINR [7]. Therefore, it is of great interest to develop a framework that calculates the output SINR in a multi-user environment by taking IPI, ICI as well as MAI and ISI into account.In this paper, we derive the analytical expression for the output SINR of a direct-sequence (DS) binary phase shift keying (BPSK) UWB system for the IEEE 802.15.3a channel models, by taking into account IPI, ICI as well as ISI and MAI. In the derivation, the second-order moments of the signal component and the interference components are calculated.