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Multi-band carrierless amplitude and phase modulation (m-CAP) is associated with subcarrier multiplexing (SCM), multi-carrier code division multiple access (MC-CDMA) and power-domain non-orthogonal multiple access (PD-NOMA) to form novel multi-user visible light communication (VLC) schemes. The combination with MC-CDMA and PD-NOMA are explored for the first time using the \pmbm -CAP modulation. In...Show More
The combination of reconfigurable intelligent surface (RIS) and multiple access technologies is an efficient solution to improve spectrum efficiency and expand network coverage. However, due to the ability of RIS in reconfiguring the channel environment, it is unknown which access technology can obtain a superior transmission effect in the RIS-assisted wireless communication network. In this paper...Show More
Non-Orthogonal Multiple Access (NOMA) is known as one of the promising techniques in the fifth generation of wireless communication. The classification of users in (NOMA) is based on power, while it is based on time, frequency and code in Orthogonal Multiple Access (OMA). In this study the downlink NOMA includes two users, one strong and one weak. The comparison of NOMA and OMA properties shows a ...Show More
Non-orthogonal multiple access (NOMA) is a technology that solves many problems in future wireless networks by providing a large number of communication capacities to the systems. The basic notion of pairing NOMA downlink networks is presented and proposed two schemes of NOMA pairing, first scheme near and far (NF) pairing and second scheme close - close or remote - remote (C-C, R-R) pairing. The ...Show More
Non-orthogonal multiple access (NOMA) is one of the most potential multiple access techniques in the next generation wireless communications system. Compared to orthogonal multiple access(OMA), NOMA shows much better performance in spectrum efficiency and system capacity. However, there is a critical problem that lie in putting NOMA into practice, that is multiple access interference cancelation(M...Show More
Non-orthogonal multiple accesses (NOMA) is one of advanced technologies which is used to improve the quality of service in fifth generation systems. Furthermore, it increases the capacity, massive connectivity, enhanced data rate, reduced latency, and minimizing the required spectrum bandwidth. On the other hand, NOMA is characterized by some disadvantages specially the problem of consuming high p...Show More
Next generation wireless technology has created revolution in the development of human life for an example 5th generation of technology. Communication over a wireless channel is quite challenging because of several factors, like channel fading, limitation of power resources especially on devices and spectrum availability. Moreover, the demand for higher data rate is ever increasing not only voice ...Show More
Two innovations multiple access technologies for efficient spectrum use in future wireless communications standards, non-orthogonal multiple access (NOMA) and cognitive radio (CR). The NOMA is one of the most promising performance improvement methods in 5G cells and CR will make the most of dynamic spectrum access and diversity throughout the broad spectrum possible, to alleviate the spectrum scar...Show More
Recently, the increasing demand of radio spectrum for the next generation communication systems due to the explosive growth of applications appetite for band-widths has led to the problem of spectrum scarcity. The potential approaches among the proposed solutions to resolve this issue are well explored cognitive radio (CR) technology and recently introduced non-orthogonal multiple access (NOMA) te...Show More
We present a non-orthogonal multiple access (NOMA) scheme based on combining orthogonal frequency-division multiple access and multi-carrier code-division multiple access. Contrary to other NOMA architectures, the proposed approach does not require any power imbalance between user signals, making it possible to grant all users the same data rate and performance. Another major contribution concerns...Show More
Massive connection and high data rates are the main requirements for next-generation networks. The next-generation networks can meet their primary requirements by using a combination of reconfigurable intelligent surfaces (RIS) and non-orthogonal multiple access (NOMA) techniques. However, the conventional NOMA’s successive interference cancellation (SIC) complexity increases significantly with th...Show More
This paper proposes a novel Ka band non-orthogonal multiple access (NOMA) uplink relay system for Lunar farside exploration, where a satellite relay node with the help of NOMA scheme, amplifies and forwards the signal from the Earth Base Station (EBS) to a Lunar rover and a lander. We assume that the signal undergoes shadowed-Rician fading for the source-relay link and Rayleigh fading for the rela...Show More
The aim of this paper is to develop hybrid non-orthogonal multiple access (NOMA) assisted downlink transmission. First, for the single-input single-output (SISO) scenario, i.e., each node is equipped with a single antenna, a novel hybrid NOMA scheme is introduced, where NOMA is implemented as an add-on of a legacy time division multiple access (TDMA) network. Because of the simplicity of the SISO ...Show More
One key advantage of 4G OFDM system is the relatively simple receiver implementation due to the orthogonal resource allocation. However, from sum-capacity and spectral efficiency points of view, orthogonal systems are never the achieving schemes. With the rapid development of mobile communication systems, a novel concept of non-orthogonal transmission for 5G mobile communications has attracted res...Show More
The key idea of hybrid non-orthogonal multiple access (NOMA) is to allow users to use the bandwidth resources to which they cannot have access in orthogonal multiple access (OMA) based legacy networks while still guaranteeing its compatibility with the legacy network. However, in a conventional hybrid NOMA downlink network, some users have access to more bandwidth resources than others, which lead...Show More
This paper studies the design of signature code multiple access (SIGMA) to support code domain non-orthogonal multiple access (NoMA). In a NoMA system, the users apply the spreading codes for multiple access that shares the same time-frequency resource element simultaneously. Consequently, multiple access interference (MAI) occurs which degrades the error performance and limits the number of conne...Show More
The integration of intelligent reflecting surface (IRS) to multiple access networks is a cost-effective solution for boosting spectrum/energy efficiency and enlarging network coverage/connections. However, due to the new capability of IRS in reconfiguring the wireless propagation channels, it is fundamentally unknown which multiple access scheme is superior in the IRS-assisted wireless network. In...Show More
In the beyond 5G networks, extraordinary demands for data rates and capacity are to be met. A possible candidate to address these challenges is Non-Orthogonal Multiple Access (NOMA) technique, which leads to higher diversity gains and massive connectivity. One caveat of NOMA is the increased receiver complexity to nullify the Inter User Interference (IUI) through Successive Interference Cancellati...Show More
Non-orthogonal multiple access (NOMA) has received considerable recent attention as a promising candidate for 5G systems. A key feature of NOMA is that users with better channel conditions have prior information about the messages of other users. This prior knowledge is fully exploited in this letter, where a cooperative NOMA scheme is proposed. The outage probability and diversity order achieved ...Show More
Non-orthogonal multiple access (NOMA) scheme has been recognized as a promising candidate for future generation networks. In order to achieve a superior spectral efficiency, the orthogonal frequency division multiplexing (OFDM) technique can be combined with the NOMA scheme. The hybrid OFDM based NOMA system, however, needs accurate information of the channel for optimum performance. In this paper...Show More
Non-orthogonal multiple access (NOMA) scheme has been recognized as a promising candidate for future generation networks. In order to achieve a superior spectral efficiency, the orthogonal frequency division multiplexing (OFDM) technique can be combined with the NOMA scheme. However, introducing OFDM into the NOMA scheme induces carrier frequency offset (CFO) errors in the system. In this paper, t...Show More
This work addresses the problem of fair power allocation policy in non-orthogonal multiple access (NOMA) system. NOMA is the multiple access (MA) scheme where data corresponding to multiple users are superimposed at the base station (BS). Data decoding at each user is done by employing successive interference cancellation (SIC) strategy. The transmission of multiple users’ data over the same carri...Show More
Current generation mobile communications require high-quality services. Adopting multiple access (MA) and multi-carrier waveforms potentially enhances the quality of services offered to end-users. However, in the majority of literature, the integration of multi-carrier and multiple-access approaches have not been extensively examined. One possible solution is to review multiple access and multi-ca...Show More
In the past few years, a large body of literature has been created on downlink Non-Orthogonal Multiple Access (NOMA), employing superposition coding and Successive Interference Cancellation (SIC), in multi-antenna wireless networks. Furthermore, the benefits of NOMA over Orthogonal Multiple Access (OMA) have been highlighted. In this paper, we take a critical and fresh look at the downlink Next Ge...Show More
Freshness of information is an important requirement in many real-time applications. It is measured by a metric called the age of information (AoI), defined as the time elapsed since the generation of the last successful update received by the destination. We consider M sources (users) updating their statuses to a base station (BS) over a block-fading multiple access channel (MAC). At the start of...Show More