Design and Evaluation of OTSM(Orthogonal Time Sequency Multiplexing) Communication System in Rayleigh Fading Channel

As a next generation waveform candidate of the OFDM (orthogonal frequency division multiplexing) system used in 4G LTE (long tern evolution) and 5G NR (new radio), the orthogonal time sequency multiplexing (OTSM) communication system has been studied and investigated for the possibility. OTSM system is a single carrier modulation scheme, which operates in delay–sequency domain. Walsh-Hadamard transform (WHT) is used to convert data from time domain to sequency domain and backwards. Modulation includes interleaving of data symbols. The paper describes OTSM system and shows its performance in Rayleigh fading channel, compared to equivalent OFDM system. OTSM system can be described as an alternative to OFDM, which shows great potential in Rayleigh fading channel in presence of Doppler shift. Performance improvement is achieved due to zero padding, or, in other words, due to guard delay between blocks, resulting in loss of data-rate, comparing to equivalent OFDM system.

I Introduction

As a next generation waveform candidate of the OFDM (orthogonal frequency division multiplexing) system used in 4G LTE (long tern evolution) and 5G NR (new radio), the orthogonal time sequency multiplexing (OTSM) communication system has been studied and investigated for the possibility. OTSM system is a single carrier modulation scheme, which operates in delay–sequency domain. Orthogonal time sequency multiplexing (OTSM) is a single carrier modulation scheme, which is based on Walsh-Hadamard transform (WHT). Initially data is formed into a grid in delay–sequency domain. Then, by applying WHT along sequency dime, data is formed into grid in delay–time domain, interleaved, and, finally, is sent through the wireless channel.