Filtreler
Threshold-Based Selective Cooperative-NOMA

Kara F. | Kaya H.

Article | 2019 | IEEE Communications Letters23 ( 7 ) , pp.1263 - 1266

In this letter, we propose threshold-based selective cooperative-NOMA (TBS-C-NOMA) to increase the data reliability of conventional cooperative-NOMA (C-NOMA) networks. In TBS-C-NOMA, the intra-cell user forwards the symbols of cell-edge user after successive interference canceler (SIC) only if the signal-to-interference plus noise ratio (SINR) is greater than the pre-determined threshold value. Hence, the data reliability of the cell-edge user is increased by eliminating the effect of the error propagation. We derive closed-form end-to-end exact bit error probability (BEP) of the proposed system for various modulation constellations . . .. Then, the optimum threshold value is analyzed in order to minimize the BEP. The obtained expressions are validated via simulations and it is revealed that the TBS-C-NOMA outperforms C-NOMA and full diversity order is achieved. © 2019 IEEE Daha fazlası Daha az

On the Error Performance of Cooperative-NOMA With Statistical CSIT

Kara F. | Kaya H.

Article | 2019 | IEEE Communications Letters23 ( 1 ) , pp.128 - 131

The demands for high spectral efficiency and massive connections led the researchers to investigate new multiple access techniques for the future wireless networks. Non-Orthogonal Multiples Access (NOMA) is one of them. Hence, the integration of NOMA technique with the other physical layer techniques, such as MIMO, cooperative communication, and cognitive radio, has recently taken considerable attention. Whereas these numerous studies are mostly devoted to reveal the overall capacity and outage performances of NOMA involved systems, the error performances have not been investigated in the literature. In this letter, we analyze error . . . performance of cooperative-NOMA, and the exact end-to-end bit error probability is derived in the closed-form. Then, the derived expressions are validated via simulations. Finally, the effect of the power allocation coefficient on the error performance is discussed. © 2019 IEEE Daha fazlası Daha az

Performance analysis of SSK-NOMA

Kara F. | Kaya H.

Article | 2019 | IEEE Transactions on Vehicular Technology68 ( 7 ) , pp.6231 - 6242

In this paper, we consider the combination between two promising techniques: Space-shift keying (SSK) and non-orthogonal multiple access (NOMA) for future radio-access networks. We analyze the performance of SSK-NOMA networks and provide a comprehensive analytical framework of SSK-NOMA regarding bit error probability (BEP), ergodic capacity, and outage probability. It is worth pointing out that all analysis also stand for conventional SIMO-NOMA networks. We derive closed-form exact average BEP (ABEP) expressions when the number of users in a resource block is equal to three (i.e., L=3). Nevertheless, we analyze the ABEP of users whe . . .n the number of users is more than three, i.e., L? 3, and derive bit-error-rate (BER) union bound since the error propagation due to iterative successive interference canceler (SIC) makes the exact analysis intractable. Then, we analyze the achievable rate of users and derive exact ergodic capacity of the users, so the ergodic sum rate of the system is in closed forms. Moreover, we provide the average outage probability of the users exactly in the closed form. All derived expressions are validated via Monte Carlo simulations and it is proved that SSK-NOMA outperforms conventional NOMA networks in terms of all performance metrics (i.e., BER, sum rate, outage). Finally, the effect of the power allocation (PA) on the performance of SSK-NOMA networks is investigated, and the optimum PA is discussed under BER and outage constraints. © 2019 IEEE Daha fazlası Daha az

Derivation of the closed-form BER expressions for DL-NOMA over Nakagami-m fading channels [Nakagami-m sönümlemeli kanallarda DL-NOMA için kapali-form BHO ifadelerinin türetilmesi]

Kara F. | Kaya H.

Conference Object | 2018 | 26th IEEE Signal Processing and Communications Applications Conference, SIU 2018 , pp.1 - 4

NOMA is as a strong candidate for the Future Radio Access Network (FRA) due to its potential to support massive connectivity and high spectral efficiency. However, the most important drawback of NOMA is the error during Successive Interference Canceller (SIC) is implemented because of the inter-user interferences. In this paper, we derive closed-form exact Bit-Error Rate expressions for Downlink(DL) NOMA over Nakagami-m fading channels in the presence of SIC errors. The derived expressions are validated by the computer simulations. It is shown that the m parameter still represents the diversity order like as OMA systems. Besides, th . . .e BER performances of users for NOMA have substantially depended on the power allocation coefficient. © 2018 IEEE Daha fazlası Daha az

Spatial multiple access (SMA): Enhancing performances of MIMO-NOMA systems

Kara F. | Kaya H.

Conference Object | 2019 | 2019 42nd International Conference on Telecommunications and Signal Processing, TSP 2019 , pp.466 - 471

The error performance of the Non-Orthogonal Multiple Access (NOMA) technique suffers from inter-user interference (IUI) although it is a promising technique for future wireless systems in terms of the achievable sum rate. Hence, a multiple access technique design with limited IUI and competitive to NOMA in terms of spectral efficiency is essential. In this paper, we consider so-called spatial multiple access (SMA) which is based on applying the principle of spatial modulation (SM) through the different users' data streams, as a strong alternative to multiple-input and multiple-output (MIMO)-NOMA systems. The analytical expressions o . . .f bit error probability (BEP), ergodic sum rate and outage probability are derived for the SMA. The derivations are validated via computer simulations. In addition, the comparison of the SMA system with NOMA is presented. The results reveal that SMA outperforms NOMA in terms of the all performance metrics (i.e., bit error rate (BER), outage probability and ergodic sum rate) besides it provides low implementation complexity. © 2019 IEEE Daha fazlası Daha az

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