A new hybrid CDMA–NOMA scheme with power allocation and user clustering for capacity improvement

Mahmood, Asif; Zeeshan, Muhammad; Ashraf, Tabinda

doi:10.1007/s11235-021-00805-x

Cited by 11 publications

(8 citation statements)

References 21 publications

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“…Projection of Equations ( 17) and ( 18) on  space is given as problem in Equation (21). The primal problem in Equation ( 19) for all  u satisfies all the constraints.…”

Section: Algorithm Descriptionmentioning

confidence: 99%

“…A clustering algorithm can optimize the usage of wireless resources 20 . Novel usage of user clustering technique is best with the poor model (users with nearest and farthest distances to BS) that improves the performance of the system 21 …”

Section: Introductionmentioning

confidence: 99%

“…20 Novel usage of user clustering technique is best with the poor model (users with nearest and farthest distances to BS) that improves the performance of the system. 21 H-NOMA with HetNet can further enhance the network capacity in 5G and B5G. [22][23][24] In addition to the H-NOMA and HetNet, the use of orthogonal user clustering can avoid interference among clusters that enhances network throughput, spectrum efficiency, user admission, and user association.…”

Section: Introductionmentioning

confidence: 99%

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Efficient resource allocation for hybrid nonorthogonal multiple access based heterogeneous networks beyond fifth‐generation

Ghafoor

Ali

Khan

et al. 2022

Trans Emerging Tel Tech

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Fifth‐generation (5G) and future beyond fifth‐generation (B5G) networks will require immense capacity due to the high rise in the number of multimedia applications and mobile devices. The heterogeneous networks (HetNets) in 5G and B5G can increase the heterogeneity and network throughput because macro base station‐only (MBS‐only) networks cannot satisfy the drastic increase in capacity demands. Hybrid nonorthogonal multiple access (H‐NOMA) can accommodate the increasing number of multimedia applications and mobile devices in 5G and B5G. H‐NOMA in B5G can also improve spectral efficiency. Before this, the researchers had not considered user clustering with H‐NOMA in HetNets. This article investigates the user clustering with downlink H‐NOMA in HetNet to maximize the network throughput in 5G and B5G. The formulated mathematical problem optimizes the considered key performance indicators (KPIs), that is, users admission in clusters, users association with base stations, power allocation to users, and network throughput. At the same time, it also satisfies the minimum transmit power and data rate requirements of users. The formulated problem is a mixed‐integer nonlinear programming (MINLP) problem. We have proposed an ϵ$$ \epsilon $$‐optimal algorithm, that is, outer approximation algorithm (OAA) to solve the MINLP problem because the complexity of the optimal exhaustive search algorithm (ESA) increases exponentially with an increase in the number of users. H‐NOMA with user clustering in HetNet is evaluated with extensive simulations to show its effectiveness regarding network throughput in 5G and B5G. We have also considered the proposed framework in the MBS‐only network and compared its performance with HetNet. The results verify that the proposed framework in HetNet performs better than the MBS‐only network. The complexity of the ϵ$$ \epsilon $$‐optimal algorithm is calculated that gives ϵ$$ \epsilon $$‐optimal results within ϵ=10prefix−3$$ \epsilon =1{0}^{-3} $$. We have also made a complexity analysis of the proposed OAA and ESA and concluded that the complexity of the proposed OAA algorithm is less than the ESA.

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“…Projection of Equations ( 17) and ( 18) on  space is given as problem in Equation (21). The primal problem in Equation ( 19) for all  u satisfies all the constraints.…”

Section: Algorithm Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Efficient resource allocation for hybrid nonorthogonal multiple access based heterogeneous networks beyond fifth‐generation

Ghafoor

Ali

Khan

et al. 2022

Trans Emerging Tel Tech

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“…The overall performance of PD-NOMA is thoroughly dependent on power allocation (PA) and user clustering techniques. The PA is established through a distance-based power allocation algorithm (DBPA) in [16,18], whereby the near-user is allocated a lower power and the far-user a higher power. User clustering techniques (Best with Best and Best with Poor models) were proposed by Hussain et al in [19,20].…”

Section: Introductionmentioning

confidence: 99%

“…In the Best with Best model, users having the same channel conditions are grouped into the same cluster, while the Best with Poor model has users in descending order of their channel gains. Orthogonal and non-orthogonal spreading codes such as(Pseudo-Noise (PN) and Walsh codes are used to distinguish equidistant users from the gNodeB in multi-cluster PD-NOMA [18]. As a result, the inter-cluster interference is overcome with the help of spreading codes and intra-cluster interference over the SIC technique.…”

Section: Introductionmentioning

confidence: 99%

Optimal Power Allocation and Cooperative Relaying under Fuzzy Inference System (FIS) Based Downlink PD-NOMA

et al. 2022

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Optimal power allocation (PA) is a decisive part of the power domain non-orthogonal multiple access (PD-NOMA) technique. In PD-NOMA, users are served at the same time and using the same frequency band, but at differing power levels. In this paper, the optimization problem for PA is formulated with distance (d), signal-to-noise ratio (SNR), and foliage depth (df) constraints. A fuzzy inference system (FIS) addresses the optimization problem by allocating the optimal power factors (power levels) to each user in the vicinity of a 5G base-station (gNodeB). The proposed system incorporates a cooperative relaying technique at the near-user to assist the far-user facing signal degradation and greater path losses. A realistic 5G micro-cell is analyzed for downlink PD-NOMA where superposition coding (SC) is used at the transmitter side, a successive interference cancellation (SIC) scheme at the near-user, and a maximum ratio combining (MRC) technique at the far-user’s receiver, respectively. For both simple PD-NOMA and cooperative relaying PD-NOMA, the presented technique’s bit-error-rate (BER) performance is evaluated against various SNR values, and it is concluded that cooperative PD-NOMA outperforms simple PD-NOMA. By combining the presented FIS system with cooperation relaying, the proposed FIS method guarantees user fairness in PD-NOMA systems while also significantly improving performance.

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Optimal packet length for non orthogonal multiple access

Alnwaimi

Boujemâa²

2022

Telecommun Syst

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A new hybrid CDMA–NOMA scheme with power allocation and user clustering for capacity improvement

Cited by 11 publications

References 21 publications

Efficient resource allocation for hybrid nonorthogonal multiple access based heterogeneous networks beyond fifth‐generation

Efficient resource allocation for hybrid nonorthogonal multiple access based heterogeneous networks beyond fifth‐generation

Optimal Power Allocation and Cooperative Relaying under Fuzzy Inference System (FIS) Based Downlink PD-NOMA

Optimal packet length for non orthogonal multiple access

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