Performance Analysis and Optimization of NOMA With HARQ for Short Packet Communications in Massive IoT

Ghanami, Fatemeh; Hodtani, Ghosheh Abed; Vucetic, Branka; Shirvanimoghaddam, Mahyar

doi:10.1109/jiot.2020.3028434

Cited by 42 publications

(20 citation statements)

References 48 publications

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“…Different transmission rounds are tested and the latency results are reduced up to 60% in the case with five transmissions. Finally, in [32], HARQ techniques are combined with NOMA for the uplink of short packet communications. Simulations include one retransmission per user and coordinated and uncoordinated transmissions.…”

Section: B Retransmissions and Diversity Schemesmentioning

confidence: 99%

Analysis of NOMA-Based Retransmission Schemes for Factory Automation Applications

et al. 2021

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New use cases and applications in factory automation scenarios impose demanding requirements for traditional industrial communications. In particular, latency and reliability are considered as some of the most representative Key Performance Indicators (KPI) that limit the technological choices addressing wireless communications. Indeed, there is a considerable research effort ongoing in the area of wireless systems, not only from academia, but also from companies, towards novel solutions that fit Industry 4.0 KPIs. A major limitation for traditional wireless architectures is related to the harsh nature of the industrial propagation channel. Accordingly, this paper addresses these challenges by studying the reliability and latency performance of the joint use of different retransmission schemes in combination with Non-Orthogonal Multiple Access (NOMA) techniques. Two general retransmission schemes have been tested: time-based and spatial diversity-based retransmissions. An adaptive injection level NOMA solution has been combined with the retransmission schemes to improve the reliability of critical information. In all cases, a particular set of simulations has been carried out varying the main parameters, such as modulation, code rate and the injection level. Moreover, the impact of the number of transmitters in relation to the communication reliability has been analyzed. Results show that spatial diversity-based retransmissions overcome considerably the reliability obtained with time-domain retransmissions while maintaining assumable latency rates.

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Section: B Retransmissions and Diversity Schemesmentioning

confidence: 99%

Analysis of NOMA-Based Retransmission Schemes for Factory Automation Applications

et al. 2021

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“…NOMA can be implemented by either power or code sharing between users [ 21 ]. NOMA is mainly analyzed in the asymptotic blocklength regime and, more recently, in the finite blocklength regime, proving that NOMA effectively provides better resource utilization and energy efficiency [ 22 , 23 , 24 ]. In [ 22 , 25 ], the authors show that NOMA outperforms OMA and reduces the latency under a finite blocklength regime.…”

Section: Introductionmentioning

confidence: 99%

“…NOMA is mainly analyzed in the asymptotic blocklength regime and, more recently, in the finite blocklength regime, proving that NOMA effectively provides better resource utilization and energy efficiency [ 22 , 23 , 24 ]. In [ 22 , 25 ], the authors show that NOMA outperforms OMA and reduces the latency under a finite blocklength regime. In NOMA, more users can be served over limited channel resources, resulting in higher spectral efficiency, which reduces latency as well [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

“…In [ 22 , 25 ], the authors show that NOMA outperforms OMA and reduces the latency under a finite blocklength regime. In NOMA, more users can be served over limited channel resources, resulting in higher spectral efficiency, which reduces latency as well [ 22 ]. These features of NOMA make it a potential candidate technique for URLLC and mMTC scenarios.…”

Section: Introductionmentioning

confidence: 99%

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Delay-Sensitive NOMA-HARQ for Short Packet Communications

Nadeem

Shirvanimoghaddam

et al. 2021

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This paper investigates the two-user uplink non-orthogonal multiple access (NOMA) paired with the hybrid automatic repeat request (HARQ) in the finite blocklength regime, where the target latency of each user is the priority. To limit the packet delivery delay and avoid packet queuing of the users, we propose a novel NOMA-HARQ approach where the retransmission of each packet is served non-orthogonally with the new packet in the same time slot. We use a Markov model (MM) to analyze the dynamics of the uplink NOMA-HARQ with one retransmission and characterize the packet error rate (PER), throughput, and latency performance of each user. We also present numerical optimizations to find the optimal power ratios of each user. Numerical results show that the proposed scheme significantly outperforms the standard NOMA-HARQ in terms of packet delivery delay at the target PER.

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“…In contrast, in a Non-Orthogonal Multiple Access (NOMA) all users share the same frequency and time intervals for their transmissions. NOMA systems outperform OMA schemes in multiple scenarios, such as downlink systems [1], visible light communication systems [2] and short packet communications [3]. Thus, NOMA plays an important role in 5G [4,5,6] and is one of the key technologies that will enable the upcoming 6G networks [7].…”

Section: Introductionmentioning

confidence: 99%