Analytical framework for UAV-enabled wireless communication with D2D networks

Device-to-device (D2D) communications allows two adjacent mobile terminals transmit signal directly without going through base stations, which has been considered as one of the key technologies for future mobile networks. As full-duplex (FD) communications can improve the performance (i.e., throughput, energy efficiency (EE)) of communications systems, it is commonly used in practical D2D communications scenarios. However, FD-enabled D2D communications also results in self-interference. To fully realize the potential benefits of FD-enabled D2D communications, an effective resource allocation mechanism is critical to avoid not only the self-interference of FD-enabled D2D communications but also the interference between D2D users (DUs) and cellular users (CUs). In this paper, we investigate the resource allocation issue for FD-enabled DUs and traditional CUs. Considering the asymmetry of energy and spectrum resources of DUs and CUs, we propose a power-spectrum trading mechanism to achieve mutual benefits for both types of users. A concave-convex procedure algorithm is employed to solve the optimization problem of power allocation, and then a maximum weighted bipartite matching based method is proposed to select proper D2D pairs to maximize the overall system throughput. Numerical results show that the proposed scheme can remarkably improve the overall throughput and EE of FD-enabled D2D communications system.

A device‐to‐device (D2D) discovery scheme is key enabler for proximity‐based services in third generation partnership project long‐term evolution‐advanced systems for public safety (PS) and general LTE scenarios. The deployment of D2D networks results in severe co‐channel interference between conventional cellular users and D2D users, and faces proximity interference management challenges because of the co‐existence of multiple D2D users. We propose a time and energy‐efficient contention‐resolving device discovery resource allocation (TEECR‐DDRA) scheme that has the capability to enhance the success ratio for discovery of D2D users by reducing collisions among users. Moreover, the proposed TEECR‐DDRA scheme has the ability to prioritise PS users to meet their QoS and latency requirements. Furthermore, multi‐channel slotted ALOHA with energy sensing can be used to increase the probability of successful discovery of non‐PS users. This ability helps to reduce the discovery time of PS users under disaster scenarios, and also reduces the energy consumption of non‐PS users by minimising the number of beacon retransmissions. System‐level simulations show that the proposed TEECR‐DDRA scheme performs remarkably well under D2D network. Compared with the conventional random access scheme, the proposed scheme almost doubles the discovery range and significantly improves the success ratio for discovery of D2D users.

Next generation high data rate applications such as High-Definition (HD) video transmission place a heavy load on wireless network resources. To achieve the strict quality of service requirements of HD video in a multi-user network requires efficient resource allocation. Rate-distortion theory provides an appropriate basis for this. The Nash Bargaining Solution (NBS) is proven to generate an optimal solution to a rate-distortion based convex resource allocation problem. Particle Swarm Optimization (PSO) is a meta-heuristic optimizer capable of generating near-optimal solutions. PSO, however, is not constrained to convex optimization problems. The motivation of this work is to demonstrate a PSO implementation capable of achieving an optimal solution to the resource allocation problem. The capability of the PSO approach to reach an optimal solution suggests its potential for resource allocation in a network of heterogeneous applications where convex optimization methods do not apply.

In the next generation (5G) wireless networks, device-to-device (D2D) communication is an important technology to improve frequency efficiency and provide proximity service. In this paper, we focus on a scenario where spare frequency resources in a cellular network are exploited by D2D users to provide local service. Considering the fact that the channel quality experienced by an end user varies from user to user due to channel fading and individual user location, resource allocation in cellular networks can make use of this channel quality information to improve throughput. Based on this concept, we propose a channel aware resource allocation scheme for both cellular and D2D users in an attempt to maximize the overall throughput in a cell. Specifically, we use the Rayleigh distribution to describe the channel quality, and formulate the resource allocation problem as an linear optimization problem, optimal resource allocation is obtained by solving the problem. Simulation results show that the overall throughput achieved by the proposed allocation schemes is significantly higher than random channel allocation and much better than a static priority scheme that allocates the best available channel to users sequentially.

In the paper, the distributed joint spectrum sharing and power allocation scheme is proposed to improve the local services in the Device-to-Device (D2D) communication underlaying cellular networks (CNs) with limited signaling overhead. The scheme aims to optimize the throughput of D2D communications over the shared uplink frequency spectrum meanwhile the base station (BS) protects the cellular users (CUs) from the interference of D2D users. Stackelberg game (SG) is formulated to model the problem for deriving the distributed scheme. In the game, the BS, as a leader, coordinates the interference from the D2D users to the cellular uplinks and maximizes its own profit by pricing the interference. On the other hand, D2D pairs, as followers, compete for the spectrum as a Nash non-cooperative game to maximize their own data rates individually. The pricing mechanism at the BS converging to the Stackelberg Equilibrium is studied. Finally, numerical examples are presented to verify the proposed scheme. It is shown that the scheme is effective on the resource allocation and the CU protection with limited signaling overhead.

<p>Device-to-device (D2D) communication can effectively use cognitive radio network approach to coexist with cellular users. For such a cognitive D2D system, two approaches (underlay and overlay) are considered to manage the spectrum sharing among the cellular (primary) users and the D2D (secondary) users. Energy efficiency (EE) is crucial in both these cases due to limited battery capacity and quality of service requirements of the D2D users. This study effectively models the power allocation problem of such a cognitive D2D system by maximising the EE of the D2D users subject to a minimum rate requirement for both the D2D users and the cellular users. This leads to a non-linear fractional optimisation problem which is more complicated and computationally intractable. Alternatively, geometric water-filling approach have been utilised for power allocation to solve this optimisation problem which results in an ‘exact’ and ‘low complexity’ solution. Simulation results reveal the benefits of the proposed algorithm.</p> <p><br></p>

This paper is devoted to studying the processes of resource allocation in dynamic resource networks. In such networks, the capacities of the arcs depend on time. Resource allocation in the network occurs in discrete time. The resource of each vertex is distributed only between adjacent vertices according to some rules. The study of the processes of resource redistribution in such networks is carried out. The main goal is to develop methods for finding the limit state (distribution) of a resource in a dynamic resource network. It is shown that the approach based on the construction of an auxiliary network is also applicable to reduce the problem of resource allocation in a dynamic network to a similar problem in an auxiliary network. Theorems on the existence of a limit state on an auxiliary graph are proved for strongly regular periodic dynamical networks. To find the limit states, one can use the approaches which are developed for the shortest path problem in dynamic networks.

D2D communications can be prone to potential security threats. For example, D2D mobiles need to know who else is located nearby so as to pair up. If the location information is spoofed, the interference caused by wrongly paired D2D users can significantly lower the system performance. Additionally, D2D communications between neighboring D2D nodes provide alternative security approaches (physical-layer security) by using channel statistics. In this chapter, we will study the following two security problems in detail. • Location security: D2D networks need to pair D2D users on the basis of location information so as to use locally available spectrum. This creates a critical loophole for global-positioning-system (GPS)-spoofing attack, where the adversary attacks the GPS signals received by D2D devices, so that D2D devices obtain false available spectrum information with false location information. This security loophole can potentially result in large-scale malfunctioning of mobile D2D networks. • Data transmission security: Security in D2D communications is traditionally implemented using cryptography, as in other wireless communication systems. Alternatively, physical-layer security provides additional security provided by the channel statistics, which fits well the D2D communications scenarios. We will consider physical-layer security in D2D communications as an underlay to cellular networks with an eavesdropper. Benefiting from the underlaid spectrum reuse, D2D users can contribute to the system's secrecy capacity, while D2D users may interfere with cellular users and decrease their secrecy capacity. Location security 8.1.1 Problem overview Dynamic-spectrum-access (DSA) technology has received much attention in industry and academic environments due to its promise of better utilization of spectrum resources compared with the current static spectrum-allocation method. Traditionally, spectrum allocation is static, where FCC assigns communities licenses to use specific frequencies, such as AM, FM, short-wave and citizens' bands, and VHF and UHF television channels, as well as hundreds of less familiar bands that serve cellular and cordless telephones, GPS trackers, air-traffic-control radars, security alarms, radio-controlled toys, and the like. While some of these assigned spectrum bands have been overloaded due to the growth of their users, other spectrum bands are scarcely used.

Performance analysis for MU-MIMO enabled LTE-U networks coexisting with D2D and WiFi network

SummaryIn this paper, we propose an energy‐efficient power control and harvesting time scheduling scheme for resource allocation of the subchannels in a nonorthogonal multiple access (NOMA)–based device‐to‐device (D2D) communications in cellular networks. In these networks, D2D users can communicate by sharing the radio resources assigned to cellular users (CUs). Device‐to‐device users harvest energy from the base station (BS) in the downlink and transmit information to their receivers. Using NOMA, more than one user can access the same frequency‐time resource simultaneously, and the signals of the multiusers can be separated successfully using successive interference cancellation (SIC). In fact, NOMA, unlike orthogonal multiple access (OMA) methods, allows sharing the same frequency resources at the same time by implementing adaptive power allocation. Our aim is to maximize the energy efficiency of the D2D pairs, which is the ratio of the achievable throughput of the D2D pairs to their energy consumption by allocating the proper subchannel of each cell to each device user equipment (DUE), managing their transmission power, and setting the harvesting and transmission time. The constraints of the problem are the quality of service of the CUs, minimum required throughput of the subchannels, and energy harvesting of DUEs. We formulate the problem and propose a low‐complexity iterative algorithm on the basis of the convex optimization method and Karush‐Kuhn‐Tucker conditions to obtain the optimal solution of the problem. Simulation results validate the performance of our proposed algorithm for different values of the system parameters.

Device-to-Device (D2D) communication has recently emerged as a promising technology to improve the capacity and coverage of cellular systems. To successfully implement D2D communications underlaying a cellular network, resource allocation for D2D links plays a critical role. While most of prior resource allocation mechanisms for D2D communications have focused on interference within a single-cell system, this paper investigates the resource allocation problem for a multicell cellular network in which a D2D link reuses available spectrum resources of multiple cells. A repeated game theoretic approach is proposed to address the problem. In this game, the base stations (BSs) act as players that compete for resource supply of D2D, and the utility of each player is formulated as revenue collected from both cellular and D2D users using resources. Extensive simulations are conducted to verify the proposed approach and the results show that it can considerably enhance the system performance in terms of sum rate and sum rate gain.

Full‐duplex relay‐assisted device‐to‐device (D2D) communication underlaying fifth generation cellular networks allow devices to exchange information directly and extend coverage via relay strategy. In this study, the authors consider such a scenario, where the D2D communications assisted by fixed‐location full‐duplex relays in interference existing circumstance. Different from previous works, they assume that there are two types of users, cellular users and D2D users. They investigate power control problem and coverage probability performance in the previously assumed situation. Therefore, an effective power control scheme is of great importance to suppress interference between D2D and cellular communications, which can improve the total system throughput and spectral efficiency. To describe it, they formulate a power control optimisation problem for cellular communication and propose a simple on–off power control algorithm for D2D communication. They also obtain an analytic expression for the coverage probability of the cellular link using stochastic geometry according to the proposed algorithm. Simulation results follow to show the rates of both cellular and D2D links in the various numbers of D2D transceivers.

Device-to-device (D2D) communication and reconfigurable intelligent surface (RIS) are well-known as two promising technologies for nextgeneration cellular communication networks. D2D users operate on the same spectrum as traditional cellular users, potentially leading to increased interference and reduced efficiency in frequency resource usage. RIS provides a remedy for clearing blocked signals from obstructions by reflecting the desired signals to the intended receiver. However, RIS elements reflect not only the desired signals but also the interference signals. This paper proposes a distance-based clustering method aimed at creating a grouping algorithm for neighboring D2D users using different channels, thereby reducing co-channel interference. The simulation indicates that the proposed clustering method for D2D users' equipment (DUEs) leads to a 0.72 dB increase in signal-to-interference-plus-noise ratio (SINR), enhances throughput to 11.25 Mbps, and reduces the bit error rate by up to 24×10⁻² compared to the baseline system. The study findings also indicate that cellular users' equipment (CUEs) experience satisfactory signal quality, even with the presence of DUEs on the cellular network. Our clustering algorithm is feasible to deploying D2D densely in RIS-aided cellular network without significantly affecting CUE performance.

With device-to-device (D2D) based relay-assisted communications, deep faded cellular users (CUs) get a better connectivity. The deep faded CU's achievable throughput of the link from base station (BS) to the CU is less than the rate demand from the CU (unsatisfied CUs). In this paper, we study the resource allocation problem for both CUs and D2D pairs to increase the achievable throughput. This is accomplished by reducing the difference between rate demand and rate achieved for the active CUs. The resource allocation optimization problem is solved in three steps. The initial set of resources that can be allocated to each active CUs is determined in the first step. In the second step, it finds the set of active CUs which needs D2D assistance and then it finds suitable D2D relay nodes (DRNs). Resource allocation to those DRNs and D2D pairs without degrading the link throughput of active CUs is performed in the third step. Numerical results shows significant amount of throughput gain for the active CUs using D2D communication. We also measure the performance of our proposed model in terms of churn rate and the number of excess resource blocks (RBs) in the system.

Energy-efficient resource allocation for D2D communication underlaying cellular networks with incomplete CSI