Performance comparison of different encoding schemes in backplane channel at 25Gbps+

As the data rate continues to increase, novel solutions to overcome the natural frequency limitations of the backplane channels are being proposed. Among them, encoding techniques that require less bandwidth for the same data rate are considered. In this paper, we analyse the impact of different encoding techniques beyond 25 Gb/sec for a link consisting of 2 daughter cards, 2 mated connectors and a backplane. Through simulation, we show how the link would perform under a suitable equalization technique for a two level non-return-to-zero (NRZ) scheme and compare the result against the performance of four level pulse-amplitude modulation (PAM4). We also include a sensitivity analysis of each scheme with respect to the changes in the high-speed characteristics of some of the key passive components.