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Underwater acoustic grid network is promising for providing high data rate and wide coverage service. For the scheduled time division multiple access (TDMA) protocols in the underwater acoustic grid networks, scheduling is an essential part to achieve reliable and energy efficient performance. Scheduling not only completely guarantees the interference free transmission in the network, but also makes...
The increasing data demand of mobile users in the rural environment makes the provision of the Internet access quite challenging. Specialized relay stations can help to enhance the network coverage, but in geographically difficult terrains with users being widely scattered, their usage becomes economically and operationally difficult. In this paper, we propose to utilize the ordinary mobile users...
In order to keep up with countless emerging applications requirements, cellular systems have to embed new flexible aspects, with the aim of satisfying future wireless environments expectations. In this context, we consider a cellular system based a full-duplex amplify-and-forward cooperative communication over Nakagami-m channel. We assume the direct link between the source and the destination is...
This paper shows the secrecy performance of a network in which secure two-way communication is possible via two half duplex decode and forward (DF) relays with an eavesdropper (EAV) trying to decode the message. In the absence of direct link from source one (S1) to source two (S2), two-way communication is established in two time phases with the help of two half duplex DF relays, first one is in broadcast...
In this work, a relay-selection scheme is proposed for underlay cognitive radio networks, with fixed and adaptive relaying power. The relay-selection and power allocation is based on the calculation of the log-likelihood ratio (LLR) value, calculated at each of the relay nodes available in the secondary network. No interference is caused to the primary network, through the satisfaction of a low power...
One of the promising enhanced features introduced in LTE-Advanced is relaying. Coverage extensions as well as enhanced throughput gain are attractive from the perspective of network operators. While functioning in the macro-overlaid network, relay offers the flexibility of random deployment (nomadic relay) at places where the communication link is congested due to an occasional event (e.g. festival)...
A novel transceiver antenna selection (TRAS) strategy selecting a pair of antennas for transmission and reception at terminal sources for full-duplex (FD) amplify-forward (AF) multi-input multi-output (MIMO) two way relay networks is offered and analyzed. Antenna pair is selected in accordance with maximum and second maximum signal to selfinterference-plus-noise ratio (SINR) between the sources and...
Radio energy harvesting model is an another method to extend the lifetime of wireless networks. In this paper, an energy harvesting model is given for amply-and-forward relay networks with aiding of ambient interferences. For this reason, the energy constrained relays harvest energy from the received signal and then use that harvested energy to amply and send that signal to the target. A time switching...
Bringing to the market intelligent vehicles is one of the current challenges faced by car manufacturers. These vehicles must be able to communicate in order to cooperate and be more effective. The issue of inter-vehicle communications is an active research topic. This paper proposes a reliable geographical broadcasting protocol which has a twofold goal: limiting the risk of interference and reducing...
While trying to get a service from the Base station it happens that many devices will find themselves competing to get the cellular service, which means each device will use the maximum power possible to win the competition, but if there is another solution that will allow the device to get what it wanted with minimum of energy, how the device will react to it? In other words, we know that the communication...
Millimeter wave (mmWave) communication is a key enabling technology for 5G cellular systems. However, due to mmWave propagation characteristics, link length for very high rates is limited and will likely necessitate the use of relay nodes for longer-range ultra-high-speed backhaul communications. This paper investigates relay selection and scheduling to support high end-to-end throughput in mmWave...
In this paper, the system-level performance of nonorthogonal multiple access (NOMA) in coordinated direct and relay transmission (CDRT) is investigated. Considering a successive interference cancellation (SIC) receiver under the 3D channel model for LTE, the system-level performance of the NOMA-CDRT is compared to the NOMA in non-coordinated direct and relay transmission (nCDRT). Simulation results...
This paper considers a relayed broadcast in IEEE 802.11 wireless local area (WLAN) networks. In the relayed broadcast, a source node intends to deliver data frames to many nodes beyond its coverage and all the nodes except the source node attempt to relay the received data frames in a contention-based and distributed manner. This traffic dissemination scheme, referred to as flooding, has several problems...
Demand for ad-hoc networks is increasing so it is expected ad-hoc networks will exist in close proximity in the future. A contention window control method, ACWA, which improves throughput of ad-hoc network against radio interference has been recently proposed. However unfairness of throughput between ACWA and DCF might be caused. We propose a modified ACWA method (GSAR scheme) which drastically improves...
In this paper, the non-regenerative relay assisted non-orthogonal multiple access (NOMA) system is proposed to enlarge the cellular coverage area and to enhance the system performance. To investigate the proposed system's performance, the closed-form expressions in terms of the system capacity are derived. In an effort to evaluate the performance of the proposed system model, the comparison between...
In this paper, we consider a two-hop cooperative relaying network in a randomly distributed interference environment, where the source communicates with the destination, assisted by N decode-and-forward (DF) relays. We consider the interference-limited environments, where the received signals at the relays and the destination are degraded by random interference nodes distributed according to homogeneous...
This paper investigates the joint power and admission control problem for a multi-pair massive multiple-input multiple-output (MIMO) amplify-and-forward relaying system. Our aim is to minimize the total transmit power for users while maximizing the number of supported users by adopting the new linear programming deflation (NLPD) algorithm. Here, the removal strategy of the NLPD algorithm is compared...
In this study, the resource blocks (RB) are allocated to user equipment (UE) according to the evolutional algorithms for long term evolution (LTE) systems. Particle Swarm Optimization (PSO) algorithm is one of the evolutionary algorithms, based on the imitation of a flock of birds foraging behavior through learning and grouping the best experience. Therefore, we propose a Simple Particle Swarm Optimization...
We study a cognitive radio network in which two sources communicate with each other through multiple relays operating in non-overlapping frequency bands in the radio spectrum. We consider the problem of optimizing the transmission powers of the sources and relays so that the minimum of the two sources' transmission capacities is maximized. Thanks to the non-overlapping nature of the relays' signals,...
Dynamic Spectrum Access (DSA) has been proposed to increase the spectrum utilization efficiency and to solve the spectrum scarcity problem. However, due to the spectrum sharing and opportunistic access nature of the DSA networks, they are more vulnerable to security threats like jammers. In this paper, we propose an anti-jamming technique in which the secondary network coordinator groups the secondary...
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