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For multiple access high data rate UWB systems, the inter-symbol-interference (ISI) and multiple access interference(MAI) will influence the performance of the systems. In this paper, a Rake receiver structure is presented with adjusting the tap weights adaptively using recursive least squares(RLS) algorithm, in which the optimal parameters of RLS algorithm can be determined by part of the channel...
This paper discusses Inter-symbol Interference (ISI) cancellation technique and the optimized energy detection receivers in ultra-wide-band impulse radio (UWB-IR) systems. As schemes of optimizing receivers, the integration interval and the sample energy threshold value are investigated. And, ISI cancellation depends on decision feedback equalization (DFE) is used. The performances are evaluated by...
In this paper, the performance of a time-division duplex ultra wideband system that has a transmitter/receiver pair of rake combining structures is optimized, where the total number of rake fingers to be deployed at the transmitter and the receiver is fixed. It is shown that there exists an optimum distribution of fingers between the two structures for systems with intersymbol interference, which...
Closed-form expressions for the output signal-to-interference-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 multiple-access interferences are considered, the derivation in this paper also takes into account inter-path and inter-chip interferences. Effects of the spreading gain and...
This contribution provides a very high data rate UWB system design based on direct sequence spreading. In order to attain >500 Mbps for short range communication, two classical solutions are feasible: either use very short spreading sequences or very large bandwidth. These classical strategies increase intersymbol interference. In contrast, our approach consists in allocating multiple long codes...
The carrier direct-sequence spread based ultrawide-band (DS-UWB) is challenging for serious inter-symbol interference (ISI) problem, which is resulted from the dense multipath with a long root-mean-square (RMS) delay spread.We adopt a RAKE-decision feedback equalizer (RAKE-DFE) receiver in this paper to cancel the ISI. Different from the conventional selective RAKE (SRAKE), we proposed the optimum...
The impulsive UWB pulses require extremely high sampling rates as well as accurate timing synchronization. Such coherent transceivers as RAKE are too complicated for current applications. The low complexity receiver provides the first commercially feasible solution to a broad class of low-data-rate applications. One approach is time reversed UWB communication as an alternative to coherent reception...
This study focuses on design of an optical ultra-wideband (UWB) pulse system with binary phase shift keying (BPSK) modulation scheme for multi-channel radio-over-fiber (ROF) communication environments. The generated optical Gaussian-like pulses can provide the several GHz bandwidths and improve the fiber dispersion and inter-symbol interference (ISI) problems for high-bit-rate transmissions. Moreover,...
In this paper we consider the coexistence issue between OFDM-based WLANs of the 802.11a family and time-hopping ultra wideband (TH-UWB) systems. A general analytical expression is provided for the bit error rate (BER) of the OFDM transceiver operating in the presence of UWB interference and the interferences caused by the multipath propagation phenomenon on the 802.11a OFDM signal, comprising intersymbol...
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