Mitigating cyclostationary noise using multi-fold turbo codes on a two-user narrowband power-line binary adder channel

Power lines present a more challenging communication environment compared to other media. Impedance mismatches and network branches render the channel frequency-selective, leading to strong inter-symbol interference (ISI). Moreover, devices connected to the power grid introduce impulsive noise on the network. Such factors may degrade the system performance drastically. Therefore, robust coding and modulation schemes are required to increase the communication reliability. Furthermore, multiple access communication allows many users to share a common medium to enhance the systems' throughput. This paper examines the behaviour of two schemes, turbo codes and multi-fold turbo codes, against a two-user adder channel under power-line conditions operating below 500 kHz. Both schemes employ distinct codes for each user and make use of orthogonal frequency-division multiplexing (OFDM) to cope with the ISI. Three configurations of a low-voltage (LV) power-line outdoor network are considered. Results obtained through simulations show that a gain, up to 3 dB, can be obtained for both users using the multi-fold turbo coding over the conventional turbo coding. The effect of iterative decoding on the performance of both schemes is also reported.