Equivalent system model and equalization of differential impulse radio UWB systems

Nonlinear Equalization for Frame-Differential IR-UWB Receivers

“…INTRODUCTION Autocorrelation Receivers (AcR) are widely used in Transmitted Reference (TR) Ultra-wide Band (UWB) communications. The authors in [1] have shown that the Inter-symbol Interference (ISI) of a frame-differential AcR and the wireless multipath propagation channel can be modelled as a second order Volterra system [2]. Thus, the output of the AcR depends non-linearly on the input data d[i] ∈ {−1, +1} where i denotes the symbol index.…”

“…If a low-data-rate scenario with a data rate up to about one-fifth of the reciprocal of the channel RMS delay spread (τ rms ) is considered, (e.g. 10 Mbps [1] at an RMS delay spread of τ rms =10ns) little ISI occurs and the conventional slicer is capable of retreiving the data without equalization. If the data rate is increased further (e.g.…”

“…Hence, the complexity of an MLSD can become very large. Differences between a nonlinear and linear distance calculation heavily affect the performance of the receiver structure [1].…”

“…al. have shown in [1], that the inter-symbol interference (ISI) can be modeled as a second order Volterra system which has several properties used throughout this paper. Since d 2 [i] ≡ 1, all the main-diagonal elements of the second order kernel matrix H 2 can be summed up in the bias term h 0 because the data dependency vanishes for these elements.…”

“…Since d 2 [i] ≡ 1, all the main-diagonal elements of the second order kernel matrix H 2 can be summed up in the bias term h 0 because the data dependency vanishes for these elements. Hence, the output of the second order Volterra system can be written as in (1) or, when including the bias term and distributing it equally on the main-diagonal of a matrix H 2,0 (cf. Fig.…”