Impacts of Narrowband Interference on OFDM-UWB Receivers: Analysis and Mitigation

Orthogonal frequency-division multiplexing (OFDM)-based ultra-wide-band (UWB) transceivers hold the promise to revolutionize the next generation of short-range wireless networks and to be adopted in electronics products for both civil and military applications. For the UWB transceivers to coexist with nearby devices, it is necessary to design efficient UWB receivers whose operation is robust to narrowband interferences (NBI). This paper conducts an in-depth analysis to establish the impacts of NBI on the performance of an OFDM-UWB receiver. A comprehensive study to assess the effects of NBI on the quantization noise in the analog-to-digital converter (ADC), timing, and carrier acquisition is presented. The analytical results show that the efficiency of the ADC is degraded by NBI, although this problem could be slightly remedied by an adaptive autogain controller (AGC). It is also found that, compared with the conventional autocorrelation-based acquisition scheme, the pseudonoise (PN) sequence matched-filtering-based acquisition scheme presents higher robustness to NBI. Nevertheless, both these two acquisition schemes fail at high interference levels. As a conclusion, it is critical to develop novel and low-complexity NBI mitigation schemes for OFDM-UWB receivers that take into account the impacts introduced by NBI