173 research outputs found
An Opportunistic-Non Orthogonal Multiple Access based Cooperative Relaying system over Rician Fading Channels
Non-orthogonal Multiple Access (NOMA) has become a salient technology for
improving the spectral efficiency of the next generation 5G wireless
communication networks. In this paper, the achievable average rate of an
Opportunistic Non-Orthogonal Multiple Access (O-NOMA) based Cooperative
Relaying System (CRS) is studied under Rician fading channels with Channel
State Information (CSI) available at the source terminal. Based on CSI, for
opportunistic transmission, the source immediately chooses either the direct
transmission or the cooperative NOMA transmission using the relay, which can
provide better achievable average rate performance than the existing
Conventional-NOMA (C-NOMA) based CRS with no CSI at the source node.
Furthermore, a mathematical expression is also derived for the achievable
average rate and the results are compared with C-NOMA based CRS with no CSI at
the transmitter end, over a range of increasing power allocation coefficients,
transmit Signal-to-Noise Ratios (SNRs) and average channel powers. Numerical
results show that the CRS using O-NOMA with CSI achieves better spectral
efficiency in terms of the achievable average rate than the Conventional-NOMA
based CRS without CSI. To check the consistency of the derived analytical
results, Monte Carlo simulations are performed which verify that the results
are consistent and matched well with the simulation results.Comment: arXiv admin note: substantial text overlap with arXiv:1709.0822
Performance Analysis of NOMA-based Cooperative Relaying in {\alpha} - {\mu} Fading Channels
Non-orthogonal multiple access (NOMA) is widely recognized as a potential
multiple access technology for efficient radio spectrum utilization in the
fifth-generation (5G) wireless communications standard. In this paper, we study
the average achievable rate and outage probability of a cooperative relaying
system (CRS) based on NOMA (CRS-NOMA) over wireless links governed by the
- generalized fading model; here and designate the
nonlinearity and clustering parameters, respectively, of each link. The average
achievable rate is represented in closed-form using Meijer's G-function and the
extended generalized bivariate Fox's H-function (EGBFHF), and the outage
probability is represented using the lower incomplete Gamma function. Our
results confirm that the CRS-NOMA outperforms the CRS with conventional
orthogonal multiple access (CRS-OMA) in terms of spectral efficiency at high
transmit signal-to-noise ratio (SNR). It is also evident from our results that
with an increase in the value of the nonlinearity/clustering parameter, the SNR
at which the CRS-NOMA outperforms its OMA based counterpart becomes higher.
Furthermore, the asymptotic analysis of the outage probability reveals the
dependency of the diversity order of each symbol in the CRS-NOMA system on the
and parameters of the fading links.Comment: 16 pages, 7 figures, 1 table, accepted in IEEE International
Conference on Communications (ICC) - 2019, Shangha
I/Q Imbalance and Imperfect SIC on Two-way Relay NOMA Systems
Abstract: 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
Fundamental Limits of Spectrum Sharing for NOMA-based Cooperative Relaying
Non-orthogonal multiple access (NOMA) and spectrum sharing (SS) are two
emerging multiple access technologies for efficient spectrum utilization in the
fifth-generation (5G) wireless communications standard. In this paper, we
present a closed-form analysis of the average achievable sum-rate and outage
probability for a NOMA-based cooperative relaying system (CRS) in an underlay
spectrum sharing scenario. We consider a peak interference constraint, where
the interference inflicted by the secondary (unlicensed) network on the
primary-user (licensed) receiver (PU-Rx) should be less than a predetermined
threshold. We show that the CRS-NOMA outperforms the CRS with conventional
orthogonal multiple access (OMA) for large values of peak interference power at
the PU-Rx.Comment: 3 figures, Accepted for presentation in GLOBECOM-NOMAT5G workshop,
Abu Dhabi, 201
Enabling full-duplex in multiple access technique for 5G wireless networks over Rician fading channels
Nowadays, unmanned aerial vehicle (UAV) relays’assisted Internet of Things (IoT) systems provide facility in order to overcome the large scale fading between source and sink. The full-duplex scheme enables wireless network to provide higher spectrum efficient technology. This paper analyses performance of two users which are served by new emerging non-orthogonal multiple access (NOMA) technique. Exact outage probability of such two users are derived and checked via Monte-Carlo simulation. These analytical results provide guideline to design UAV in real application. This paper provides a comprehensive study to examine impact of interference, fixed power allocation factors to system performance
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