Abstract
Superposed multicarrier transmission scheme is known to improve frequency utilization efficiency where several wireless systems share spectrum. In the superposed multicarrier transmission scheme, interference can be suppressed by setting corresponding initial log likelihood ratio (LLR) to proper values determined by desired to undesired power ratio (DUR). To estimate the interference power and affected subcarriers, a scheme based on a residual power calculated by subtracting hard replica signal from received signal is proposed. This scheme uses CRC check and generates replica from only error-free signals. Thus, it requires longer detection period if the noise power or the interference power is large because less correct packets are received. Moreover, the detectable type of interference is limited to only wide-band interference. In this report we propose a superposed band and interference power estimation technique based on the residual power. Our proposed scheme adopts Robust LLRs and averages the residual power over all packets even if these contain bit errors. Simulation results indicate that the proposed method performs fast interference detection while maintain the conventional DUR estimation accuracy.
