Non-Gaussian interference vulnerability of coding schemes used for control channels in 4G and 5G

The control channels in the radio access mobile network 4G and 5G are essential for the system to work. For this issue, the channels are designed with forward error correction (FEC) codes and modulation to be very robust to interference. In general, most evaluations of the performance and, in particular, the robustness against interference are assuming an interference environment consisting of additive white Gaussian noise (AWGN). In this work, the adopted FEC and modulation for the control channels in 4G and 5G are investigated in non-Gaussian noise modelled by a Middleton’s class A model or a Gaussian mixture model. It is demonstrated that both the FEC scheme and rate matcher in 4G and the newly proposed Polar code in combination with its rate matcher perform very well in non-Gaussian noise. The performance is better or resembles the performance of AWGN. The solution for 5G achieves better performance than the one for 4G, when analysing the performance for a certain $E_{b} / N_{I}$. However, when comparing the performance for a specific channel SIR, the behaviour is the opposite and the implementation using in 4G has a slightly lower packet error rate. Results also show that it is important that the rate recovery function in the receiver is implemented with soft combining of the repeated information.