In this work, non-orthogonal multiple access (NOMA) in coordinated direct and relay transmission (CDRT) is introduced, where a base station (BS) directly communicates with user equipment 1 (UE1) while communicating 2 (UE2) only through relay. The main challenge of nonorthogonal CDRT can be solved by using the inherent property NOMA that allows receiver to obtain side information such as other TIE's data for interference cancellation. Analytical expressions outage probability ergodic sum...

In this letter, we propose the cooperative relaying system using non-orthogonal multiple access (NOMA) to improve spectral efficiency. The achievable average rate of proposed is analyzed for independent Rayleigh fading channels, and also its asymptotic expression provided. addition, a suboptimal power allocation scheme NOMA used at source proposed.

This letter proposes a device-to-device (D2D) aided cooperative relaying system (CRS) using non-orthogonal multiple access (NOMA) to enhance the spectral efficiency. In addition, power allocation strategy is proposed achieve maximum capacity scaling according signal-to-noise ratio (SNR). The D2D CRS NOMA with shown improve achievable rate greatly compared conventional CRSs and without NOMA. particular, it proved that sum-capacity log SNR for one, whereas (2/3) ones.

This paper analyzes the outage probability of multi-branch dual-hop decode-and-forward (DF) cooperative relaying systems over non-identical Nakagami/Nakagami fading channels. The derives an exact closed-form expression for with maximum ratio combining considering both effect co-channel interference (CCI) and addictive white Gaussian noise. results this show that a DF system is more vulnerable to noise than low moderate SINR, whereas it susceptible high SINR diversity order. Moreover, shows...

This letter investigates a symbol error rate (SER) performance of the downlink non-orthogonal multiple access (NOMA) scheme with symbol-level successive interference cancellation (SIC). Exact and closed-form expressions for average SERs individual users are derived under Rayleigh fading channels considering imperfect SIC when square quadrature amplitude modulation (QAM) symbols two superposed transmitted using NOMA. In addition, power allocation criterion NOMA is provided design feasible QAM...

In this letter, a BER study is presented for decode-and-forward (DF) relaying in independent but not identically distributed Rayleigh fading channels. For an arbitrary number of relays, exact and closed-form expressions the are provided M-ary PAM, QAM PSK, respectively. It also shown that analytic results perfectly matched with simulated ones

To extend the transmission range governed by limited transmit power, collaborative beamforming (CB) can be employed with a virtual antenna array (VAA) constructed an unmanned aerial vehicle (UAV) swarm. CB techniques combined physical layer security (PLS) algorithms are known to better secure transmissions of sensitive information in presence eavesdropping attacks, compared co-located antenna-based schemes. In particular, analog (ACB) random VAA topologies, which is suitable for UAV networks...

In this letter, we present the outage performance of decode-and-forward based cooperative multicast systems with best relay selection (CM-RS) over Rayleigh fading channels. Especially, provide an exact and closed-form expression for probability CM-RS its diversity order. Through numerical results, analysis is verified, compared that a single-hop system.

In this letter, we consider the fifth-generation (5G) wireless backhaul network with small cells and millimeter-wave (mm-Wave) communication. We assume mm-Wave is used for a physically separated 5G macro base station (MBS) to communicate small-cell stations (SBSs) that have wired connections each other. Thus, user in coverage of SBSs can receive its desired signal when at least one connected MBS. However, blockage problem line-of-sight paths induce an outage event Using stochastic geometry...

A wireless sensor network (WSN) refers to a of nodes that collaboratively work sense, monitor, and control their surrounding environments. As WSNs are integrated into the Internet Things, it is crucial protect against malicious security attacks considering its wide applicability, such as military monitoring, healthcare, civilian applications. Thus, in this paper, we consider physical-layer technique exploiting analog cooperative beamforming (ACB), where multiple create virtual antenna array...

Wireless dual-hop relaying is envisioned to provide better coverage as well signal reliability for existing single-hop wireless communication systems. The simplest feature of the relay has attracted increasing interest from research and commercial communities. Emerging transmit diversity techniques using space-time transmission with multiple antennas could further enhance performance. In this paper, we examine allocation limited power source transmitter relay. We finally compare different...

We present a study on the outage probability of multihop wireless communication systems with multiple-input multiple-output (MIMO) link based transmit antenna selection and maximal-ratio combining (MRC) at receiver. A nonregenerative system (NS) is investigated an ideal amplifying gain. MIMO channels are assumed in uncorrelated Rayleigh fading.We derive moment generating function (MGF) reciprocal end-to-end signal-to-noise ratio (SNR) obtain closed-form approximation through numerical...

In the sixth-generation (6G) communications, how to deploy and manage massively connected Internet-of-Things (IoT) nodes will be one of key technical challenges, because 6G is expected provide 10 times higher connection, compared 5G. At same time, due sharp growth in devices newly adopted technologies, learning-based attacks big data breaches are occur more frequently. With advances quantum computing future, conventional cryptography-based security protocols may obsolete future wireless...

We propose a distributed medium access control (MAC) protocol called carrier sense multiple with collision resolution (CSMA/CR) by extending the wireless CSMA/CD protocol. The proposed CSMA/CR identifies additional sensing after data transmission starts. If one station detects collision, it transmits jam signal to stop other stations' transmissions and then retransmits without backoff, which resolves next that may occur. throughput analysis shows outperforms conventional CSMA-based MAC protocols.

Innon-orthogonal multiple access (NOMA) systems, transmit power allocation plays a crucial role in maximizing the sum rate, while satisfying quality of service requirements users. In prior study, an interior point method (IPM) has been presented as iterative algorithm for allocation, which can maximize rate and minimize outage rate. However, such algorithms typically suffer from low computational efficiency excessively high latency. To overcome these limitations, machine learning-based...

In this letter, we propose an analog cooperative beamforming (ACB) technique using random antenna arrays for physical-layer (PHY) secure communications, where the array elements are assumed to be uniformly distributed in a spherical volume. Motivated by fact that sidelobe of radiating at undesired directions can used eavesdropping, proposed ACB aims randomizing radiation pattern PHY communications. To achieve aim, it allows randomly selected and adapt their phases desired direction. evaluate...

In this paper, the best relay selection (BRS) is proposed for cooperative relaying system based on non-orthogonal multiple access (NOMA). Approximate and asymptotic expressions average rate of scheme are derived under independent Rayleigh fading channels. Numerical results show that NOMA-based BRS (N-BRS) attains more gain than conventional (C-BRS) when a number relays becomes large.

We demonstrate a vertical organic light emitting transistor (VOLET) showing high current on/off ratio through dielectric encapsulation of finger-like source electrode, which is placed between the bottom gate electrode and top drain electrode. In such VOLET configuration, charge transport occurs largely from to an underlying semiconductor (OSC) layer interface OSC insulator. Accordingly, leakage greatly reduced transistor-type switching behavior with achieved. The our about 100 times higher...

We consider device-to-device (D2D) communications in millimeter-wave (mm Wave) for the future fifth generation (5G) cellular networks. While mm Wave systems can support multiple D2D pairs simultaneously through beamforming with highly directional antenna arrays, channel is significantly more susceptible to blockage compared microwave; studies indicate that if line-of-sight (LoS) paths are blocked, reliable may not be achieved high data-rate applications. Therefore, assuming an outage occurs...

Low Earth orbit (LEO) satellite communication in the sixth-generation (6G) of cellular networks is expected to redefine fabric global connectivity through integration with aerial platforms. However, for successful deployment LEO satellites, excessive Doppler shift issue should be addressed by effective estimation and compensation techniques, as they move rapidly their orbits. Therefore, this letter, we investigate such shifts links between an unmanned vehicle (UAV) swarm a three-dimensional...