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Having adequate robustness to variations of both weight coefficient and integration interval, the weightedtransmitted reference (WTR) system can achieve a superior performance and support high data rate ultra-wideband (UWB) communications as well. To benefit from these excellent advantages without using ultra-wideband analog delay lines, in this paper, a finite-resolution digital receiver is proposed. The performance of the proposed receiver is evaluated at a data rate of 114Mbps averaged over 100 realizations of IEEE 802.15.3a channel model 1 (CM1) for different quantization levels of finite-resolution analog-to-digital converters (ADCs) operating at Nyquist rate, taking into account noise, inter-path/pulse interference (IPaI/IPI), and inter-symbol interference (ISI). The effects of sampling rates, number of reference pulses, and the ADC threshold(s), weight coefficient, and summation interval on the receiver performance are also investigated. The evaluation results show that the proposed receivers using finite-resolution ADCs only suffer a performance degradation of several dB as compared to the full-resolution ADC and analog receivers. Therefore, employing finite-resolution ADCs could be a promising approach to implement the WTR receivers without using ultrawideband analog delay lines.

In this paper, a blind narrowband interference (NBI) mitigation technique using the combination of a square law (SL) device and a band pass filter (BPF) is proposed for energy detection (ED) based ultra-wideband (UWB) receivers. Both theoretical analysis and computer simulations show that without requiring any prior knowledge about the NBI, the SL technique can considerably improve signal-to-interference ratio of the received UWB pulses and hence allows ED-based UWB receivers achieve much better bit error rate. Furthermore, the proposed SL technique has the same NBI mitigation performance as the Teager-Kaiser operator (TKO) technique. Unlike TKO, there are many commercial off-the-shelf SL devices are available for IR-UWB applications. Thus, the proposed SL technique is a simple, implementable, and highly effective blind NBI mitigation technique for ED-based IR-UWB receivers.Index Terms-Ultra-wideband, energy detection, narrowband interference, Teager-Kaiser operator, square law device.

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In this paper, a low complexity suboptimal monobit receiver, denoted as Q-function estimation (QFE) based monobit receiver, is proposed for transmitted-reference (TR) based impulse radio (IR) ultra wideband (UWB) systems to mitigate the performance degradation caused by severe quantization noise due to employing monobit ADCs. Through accumulating reference samples over multiple blocks, the QFE-based monobit receiver can considerably reduce the noise-on-noise effect and optimize the contribution of each sample to the decision statistic. Computer simulations demonstrate that in both line-of-sight (LOS) and non-LOS (NLOS) channels the QFE-based monobitweighted TR receiver can achieve a close-to-optimal bit-error rate (BER) performance without requiring full channel state information. Furthermore, because the optimal combining weights can be obtained offline and saved into a lookup table, the complexity of the proposed suboptimal monobit receiver is quite low. Therefore, it is considered as a promising technology for IR-UWB applications requiring low system complexity and low power consumption.