Shannon bounds on the throughput for Gaussian, bi-level, block interference channels

Results are presented on code performance and capacity bounds for channels with Gaussian, bi-level, block interference for binary and nonbinary modulation, noncoherent demodulation, and soft-decision decoding. Each transmitted block is corrupted by additive white Gaussian noise that has one of two power spectral densities. The smaller of the two is the power spectral density of the thermal noise, and the difference between the two spectral densities is the power spectral density of the interference noise. The average power in the interference is constant, so the power spectral density of the interference is inversely proportional to the average fraction of the blocks that have interference. This block interference channel has been used to model partial-band interference in frequency-hop communications and to model pulsed interference in a number of communication systems. Throughput results for turbo-product and low-density parity-check codes that are used on Gaussian block interference channels are compared with the capacity bounds for such channels. For some code rates, we show that the throughput of the codes and the capacity bounds are both nonmonotonic functions of the fraction of the blocks that have interference. Applications to adaptive-rate coding are discussed.