Doppler Resilient Orthogonal Time-Frequency Space (OTFS) Systems Based on Index Modulation
Yu Liang, Lingjun Li, Pingzhi Fan, Yong Liang Guan
Abstract
High mobility and high spectrum efficiency are two main challenges for 5G communication. Many new technologies are proposed to meet these requirements. Orthogonal time frequency space (OTFS) is a novel scheme to combat the high Doppler effect under time-varying channel. In this paper, an index modulation based orthogonal time frequency space (OTFS-IM) system is proposed for improving BER performance under both high mobility and high spectrum efficiency. In the scheme, the information is conveyed by both constellation symbols and indices bits on Delay-Doppler domain. A low complexity detection strategy based on integrated MMSE-ML detection is proposed, which is very flexible and suitable to high spectrum efficiency signal. By simulation, compared with the conventional OTFS, the proposed OTFS-IM system can achieve better BER performance, maintaining good tolerability against Doppler effect, especially for higher spectral efficiency.