NOMA with imperfect SIC implementation

Manglayev, Talgat; Kızılırmak, Refik Çağlar; Kho, Yau Hee; Bazhayev, Nurzhan; Lebedev, Ilya

doi:10.1109/eurocon.2017.8011071

Cited by 31 publications

(18 citation statements)

References 5 publications

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“…To increase the system throughput and to ensure secure communications, the authors in [18] derived closed-form expressions of the ergodic secrecy rates under both non-colluding and colluding eavesdroppers in a TWR C-NOMA network. In order to achieve a balance between spectral efficiency and energy conservation, power allocation was discussed for a TWR C-NOMA system in [19].According to the principle of NOMA, downlink users with stronger channel gains need to decode signals of other users with lower channel gains before decoding their own signals based on the SIC technique [20]. The NOMA systems with perfect SIC (pSIC) conditions were investigated in most of the above works, which is too idealistic.…”

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confidence: 99%

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I/Q Imbalance and Imperfect SIC on Two-Way Relay NOMA Systems

Tian

et al. 2020

Electronics

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Non-orthogonal multiple access (NOMA) system can meet the demands of ultra-high data rate, ultra-low latency, ultra-high reliability and massive connectivity of user devices (UE). However, the performance of the NOMA system may be deteriorated by the hardware impairments. In this paper, the joint effects of in-phase and quadrature-phase imbalance (IQI) and imperfect successive interference cancellation (ipSIC) on the performance of two-way relay cooperative NOMA (TWR C-NOMA) networks over the Rician fading channels are studied, where two users exchange information via a decode-and-forward (DF) relay. In order to evaluate the performance of the considered network, analytical expressions for the outage probability of the two users, as well as the overall system throughput are derived. To obtain more insights, the asymptotic outage performance in the high signal-to-noise ratio (SNR) region and the diversity order are analysed and discussed. Throughout the paper, Monte Carlo simulations are provided to verify the accuracy of our analysis. The results show that IQI and ipSIC have significant deleterious effects on the outage performance. It is also demonstrated that the outage behaviours of the conventional OMA approach are worse than those of NOMA. In addition, it is found that residual interference signals (IS) can result in error floors for the outage probability and zero diversity orders. Finally, the system throughput can be limited by IQI and ipSIC, and the system throughput converges to a fixed constant in the high SNR region.Electronics 2020, 9, 249 2 of 16 signals of other users with lower channel gains before decoding their own signals based on the SIC technique [7]. Hence, NOMA can support multiple users with limited resources and improve spectral efficiency, which has attracted considerable attention from academia and industry. For instance, in [8,9], the authors discussed power allocation under various criteria for a downlink NOMA system. In order to improve the system throughput, a network NOMA technique was proposed and analysed for the uplink coordinated multi-point transmission (CoMP) in [10].Cooperative communications is another solution to mitigate the fading effects of wireless environments [11]. NOMA in cooperative communication systems is commonly referred to as cooperative-NOMA (C-NOMA), which is able to enhance the system reliability [12]. The authors analysed the effect of the power allocation coefficient on the error performance under a one-way relay C-NOMA system in [13]. The authors in [14] presented a new system detection scheme for a one-way relay C-NOMA system, which used the maximal ratio combining (MRC) and SIC to decode signals. Sheng Luo et al. in [15] proposed an adaptive transmission scheme based on a one-way relay C-NOMA network with a dedicated relay, which could temporarily store the received information. Recently, two-way relaying (TWR) has attracted a great deal of research attention because of its ability to achieve higher spectral efficiency in comparison to one-way relayin...

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confidence: 99%

“…According to the principle of NOMA, downlink users with stronger channel gains need to decode signals of other users with lower channel gains before decoding their own signals based on the SIC technique [20]. The NOMA systems with perfect SIC (pSIC) conditions were investigated in most of the above works, which is too idealistic.…”

mentioning

confidence: 99%

I/Q Imbalance and Imperfect SIC on Two-Way Relay NOMA Systems

Tian

et al. 2020

Electronics

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“…Towards this end, scenarios with both direct {S→D} connectivity and relay selection can provide additional degrees of freedom to the transmission [52], thus improving the performance of NOMA. Also, practical issues, such as outdated CSI [9]- [11] and imperfect SIC [53] should be considered when selecting the relay in NOMA and hybrid NOMA/OMA networks.…”

Section: Discussionmentioning

confidence: 99%

Hybrid NOMA/OMA With Buffer-Aided Relay Selection in Cooperative Networks

Νομικός

Charalambous

Vouyioukas

et al. 2019

IEEE J. Sel. Top. Signal Process.

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Non-orthogonal multiple access (NOMA) aims to increase the spectral efficiency of fifth generation (5G) networks by relaxing the orthogonal use of radio-resources. In this work, a network with multiple half-duplex (HD) buffer-aided (BA) relays is considered, where the source transmits with fixed rate towards two users. The users might demand the same rate by the source (e.g., two cellular users requiring the same service), or they could have different rate requirements (e.g., a cellular user coexisting with an Internet of Things (IoT) device). By deploying multiple BA relays, increased reliability and additional degrees of freedom are provided. Leveraging the spectral efficiency of NOMA and the increased diversity gain of BA relaying, two relay selection algorithms with broadcasting are proposed for power-domain (PD) NOMA and hybrid NOMA/OMA, namely BA-NOMA and BA-NOMA/OMA, respectively. BA-NOMA can improve the performance in terms of outage probability when the power allocation factor α is selected such that robustness against channel uncertainties due to, e.g., outdated channel state information (CSI), is provided. Moreover, BA-NOMA/OMA further improves the sum-rate by switching to OMA when the relays cannot serve the users through NOMA. For both cases, a theoretical analysis for the outage probability is conducted and the asymptotic performance is studied. Finally, numerical results and comparisons with other state-of-the-art algorithms are provided for the outage probability, average throughput and average delay.

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“…NOMA is able to distinguish different users via successive interference cancellation (SIC) [10] or multiple user decoding (MUD) [11]. Besides the very first version [12], the state-of-the-art (SOA) NOMA includes multiuser shared access (MUSA) [13], pattern division multiple access (PDMA) [14], sparse code multiple access (SCMA) [15], etc. SIC was employed in [12][13][14] and has practical challenges:…”

Section: A Challenges For Existing Nomamentioning

confidence: 99%

Efficient Sparse Code Multiple Access Decoder Based on Deterministic Message Passing Algorithm

Zhang

Yang

Pang

et al. 2020

IEEE Trans. Veh. Technol.

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Being an effective non-orthogonal multiple access (NOMA) technique, sparse code multiple access (SCMA) is promising for future wireless communication. Compared with orthogonal techniques, SCMA enjoys higher overloading tolerance and lower complexity because of its sparsity. In this paper, based on deterministic message passing algorithm (DMPA), algorithmic simplifications such as domain changing and probability approximation are applied for SCMA decoding. Early termination, adaptive decoding, and initial noise reduction are also employed for faster convergence and better performance. Numerical results show that the proposed optimizations benefit both decoding complexity and speed. Furthermore, efficient hardware architectures based on folding and retiming are proposed. VLSI implementation is also given in this paper. Comparison with the state-of-the-art have shown the proposed decoder's advantages in both latency and throughput (multi-Gbps).Index Terms-Sparse code multiple access (SCMA), deterministic message passing algorithm (DMPA), folding, retiming, VLSI.• Error propagation: For SIC, if an error occurs, all users afterward are likely to be decoded incorrectly.• Decoding latency: User power sorting is involved in SIC, and causes good overhead latency compared to other methods. Since the data with the lowest power is decoded last, the latency will even higher. Therefore, SCMA employs MUD instead of SIC. Thanks to its sparsity, message passing algorithm (MPA) can be applied for better decoding performance. B. Sparse Code Multiple AccessSCMA was proposed in 2013 [15], trying to increase user scale via a new perspective: enabling more efficient multiple access by non-orthogonal sparse spreading codes of users.1) Properties of SCMA: As a promising MA, SCMA has the properties: i) multiplexing in frequency domain; ii) codebook based on both mapping and spreading; iii) multidimensional constellation for shaping gain and spectral efficiency; iv) non-orthogonality ensuring more accessed users; v) spreading which reduces noise interference and enhances system robustness; and vi) sparsity which reduces decoding complexity. Thanks to these properties, SCMA is more physically realizable and overloading tolerant, compared to other MAs [16]. Details of SCMA can be found in Section II.2) Challenges of SCMA:• Throughput: Though the throughput of SCMA outperforms other MAs, especially orthogonal ones, it is hard to

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NOMA with imperfect SIC implementation

Cited by 31 publications

References 5 publications

I/Q Imbalance and Imperfect SIC on Two-Way Relay NOMA Systems

I/Q Imbalance and Imperfect SIC on Two-Way Relay NOMA Systems

Hybrid NOMA/OMA With Buffer-Aided Relay Selection in Cooperative Networks

Efficient Sparse Code Multiple Access Decoder Based on Deterministic Message Passing Algorithm

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