A Study on Interference Suppression Technique by Partitioned Frequency- and Time-domain Processing for Dynamic Spectrum Access

摘要

This paper studies on interference suppression techniques for dynamic spectrum access (DSA). For DSA systems, it is important to avoid interference to high-priority systems caused by low-priority systems. Generally, OFDM based transmission induces high out-of-band emission because of the side-lobes of the transmitted sub-carriers. Therefore, interference suppression techniques are needed for OFDM based DSA systems. Active Interference Cancellation (AIC) is known as a frequency-domain processing solution, which is capable of creating a deep notch with narrow bandwidth. However, the AIC doesn't take enough advantage on suppression gain for wider bandwidth interference avoidance notch. In this paper, we propose an Interference Suppression technique by Partitioned Frequency- and Time-domain (IS-PFT) processing to achieve high suppression gain for wider bandwidth interference avoidance band. The IS-PFT is configured by partitioned combination of the AIC in frequency-domain and a windowing processing in time-domain. It is shown by computer simulations that the interference power spectrum density is reduced by 6 [dB] at maximum for the IS-PFT compared to the conventional method in a condition of considering a wireless microphone in Digital terrestrial TV (DTV) band. Moreover, it is shown that the interference power of the IS-PFT is reduced by 2 [dB] compared to the conventional method in a condition of the adjacent DTV channel use.