دانلود رایگان ترجمه مقاله مطالعه‌ جامع و مقایسه طرح های نسل پنجم NOMA (نشریه IEEE 2018)

مطالعه‌ جامع و مقایسه طرح های نسل پنجم NOMA

Comprehensive study and comparison on 5G NOMA schemes

Abstract

Compared to the traditional orthogonal multiple access (OMA), non-orthogonal multiple access (NOMA) technology can achieve higher spectrum efficiency and support more massive connectivity. In this article, we conduct comprehensive study and comparison on current NOMA technologies that many mainstream companies have proposed for the fifth generation (5G) wireless communication standard. According to the characteristics of the NOMA schemes, we classify these schemes into four categories: scrambling-based NOMA, spreading-based NOMA, coding-based NOMA and interleaving-based NOMA. We systematically summarize the transceiver block diagram of each category, and detail basic principles, key features and transmission-reception algorithms of all NOMA schemes. Furthermore, the theoretical analysis based on average mutual information is given to evaluate the achievable sum-rate performance of the NOMA systems and their potential performance gains as compared with OMA. Comprehensive simulations are carried out for the block-error-rate (BLER) performance evaluation of these NOMA schemes as well, which coincide with the theoretical analysis. By comparing the performance of these technologies, some promising schemes and directions are suggested for the future 5G NOMA development.

1 Introduction

WITH the rapid development of mobile Internet of things (IoT), much more user equipments (UEs) and much higher data-rate pose big challenges for the future mobile wireless network. In 2014, the international mobile telecommunication (IMT)-2020 promotion group proposed the vision and requirements of the fifth generation (5G) wireless communication. The 5G system aims to support much higher spectral efficiency (SE) and much more massive connectivity, and new non-orthogonal multiple access (NOMA) is one key technology to meet these strict requirements [1]–[4]. The typical application scenarios of 5G consist of enhanced Mobile BroadBand (eMBB), massive Machine Type Communications (mMTC), and Ultra-Reliable and Low Latency Communications (URLLC). Each scenario has distinct service feature and requirement. High SE (up to 15bps/Hz for uplink and 30bps/Hz for downlink), massive connection (1 million devices/km2 ) and ultra reliability ( 10−5 packet error rate within 1ms user-plane latency) are key performance indicators (KPIs) for eMBB, mMTC and URLLC [5], respectively. The study on NOMA started from the 3rd generation partnership project (3GPP) Release 14 (Rel-14) since September 2014, and it is ongoing at the study-item (SI) step of 3GPP Rel-15 until May 2018. The current target is to provide self evaluation against eMBB, mMTC and URLLC requirements and test environments for 5G new radio (NR) standardization. By the end of June 2019, 3GPP Rel-16 will accomplish the final 5G NR submission, including description template, compliance template, and self evaluation results.

The conventional orthogonal multiple access (OMA) technology allocates orthogonal time and frequency resources for multiple users, and each user’s receiver can take advantage of this orthogonality to separate out its own signal from others simply. The NOMA technique utilizes the superposition coding principle to multiplex multiple users onto the same time and frequency resources. Therefore, NOMA can enlarge the number of connections by introducing controlled symbol collisions. Actually, NOMA can approach the capacity bound of the multi-user system more closely than OMA [6]. For the sake of intuition, consider a simple two-user uplink multiple access (MAC) system on the additive white gaussian noise (AWGN) channel.