OTFS Enabled NOMA for MMTC Systems over LEO Satellite

• 作者: MA Yiyan MA Guoyu WANG Ning ZHONG Zhangdui AI Bo
• 来源期刊: 中兴通讯技术（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: Special Topic
• 页码范围: 63-70
• 页数: 8页
• 语种: 英文
• DOI: 10.12142/ZTECOM.202104007

摘要

As a complement of terrestrial networks, non-terrestrial networks (NTN) have ad? vantages of wide-area coverage and service continuity. The NTN is potential to play an impor? tant role in the 5G new radio (NR) and beyond. To enable the massive machine type communi? cations (mMTC), the low earth orbit (LEO) satellite is preferred due to its lower transmission delay and path loss. However, the LEO satellite may generate notable Doppler shifts to de? grade the system performance. Recently, orthogonal time frequency space (OTFS) modulation has been proposed. It provides the opportunity to allocate delay Doppler (DD) domain resourc?es, which is promising for mitigating the effect of high mobility. Besides, as the LEO satellite constellation systems such as Starlink are thriving, the space spectrum resources have become increasingly scarce. Therefore, non-orthogonal multiple access (NOMA) is considered as a candidate technology to realize mMTC with limited spectrum resources. In this paper, the ap?plication of OTFS enabled NOMA for mMTC over the LEO satellite is investigated. The LEO satellite based mMTC system and the OTFS-NOMA schemes are described. Subsequently, the challenges of applying OTFS and NOMA into LEO satellite mMTC systems are discussed. Fi?nally, the potential technologies for the systems are investigated.