Spectrum utilization efficiency of cognitive radio systems with limited sampling capability: The impact of spectrum non-contiguity

In cognitive radio systems, the available frequency bands are usually non-contiguous, which may cause impact on the spectrum utilization efficiency (SUE).When the receiver has a limited sampling capability, the aliasing phenomenon may cause interference among the signals at different frequency points, thus causing the loss of channel capacity. Information theoretic analysis is carried out to quantify the impact of spectrum non-contiguity on the channel capacity by analyzing the SUE. Beginning from the single sampler case, the analysis is also extended to the general case of sampler arrays. Numerical results are provided to answer several important questions on the impact of spectrum non-contiguity.