Improvement in active interference cancellation technique using guard carriers in MB-OFDM UWB system

In 2002, FCC has allocated a wide band (3.1-10.6 GHz) of spectrum to UWB systems which can be used without licence but there are some narrowband system already operating in the same frequency band. In order to coexist with existing systems, multiband-OFDM systems should have cognitive radio capabilities to detect and avoid interference to primary user (PU). Active interference cancellation technique is very effective technique to mitigate interference to narrowband systems. In this paper improvement in AIC is proposed by utilizing guard carriers. A notch gain of around 8dB over conventional AIC scheme is achieved.