Interference Exploitation in D2D-enabled Cellular Networks: A Secrecy Perspective

We investigate power control problem for cooperative relaying in the device-to-device (D2D) system underlaying cellular networks. Specifically, we consider the D2D communication assisted by fixed-location relays in interference existing circumstance. 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. In this paper, we formulate a power control optimization problem for cellular communication and a simple on-off power control algorithm for D2D communications. We also obtain analytic expression for the coverage probability of cellular link using stochastic geometry according to proposed algorithm. Simulation results follow to show the rate of both cellular and D2D links in the various number of D2D transceivers.

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.

Mobile cellular communications are experiencing an exponential growth in traffic load on Long Term Evolution (LTE) eNode B (eNB) components. Such load can be significantly contained by directly sharing content among nearby users through device-to-device (D2D) communications, so that repeated downloads of the same data can be avoided as much as possible. Accordingly, for the purpose of improving the efficiency of content sharing and decreasing the load on the eNB, it is important to maximize the number of simultaneous D2D transmissions. Specially, maximizing the number of D2D links can not only improve spectrum and energy efficiency but can also reduce transmission delay. However, enabling maximum D2D links in a cellular network poses two major challenges. First, the interference between the D2D and cellular communications could critically affect their performance. Second, the minimum quality of service (QoS) requirement of cellular and D2D communication must be guaranteed. Therefore, a selection of active links is critical to gain the maximum number of D2D links. This can be formulated as a classical integer linear programming problem (link scheduling) that is known to be NP-hard. This paper proposes to obtain a set of network features via deep learning for solving this challenging problem. The idea is to optimize the D2D link schedule problem with a deep neural network (DNN). This makes a significant time reduction for delay-sensitive operations, since the computational overhead is mainly spent in the training process of the model. The simulation performed on a randomly generated link schedule problem showed that our algorithm is capable of finding satisfactory D2D link scheduling solutions by reducing computation time up to 90% without significantly affecting their accuracy.

Device‐to‐device (D2D) communication underlaying cellular networks is a promising technology to improve network resource utilization. In D2D‐enabled cellular networks, interference among spectrum‐sharing links is severer than that in traditional cellular networks, which motivates the adoption of interference cancelation (IC) techniques at the receivers. However, to date, how IC can affect the performance of D2D‐enabled cellular networks is still unknown. In this paper, we present an analytical framework for studying the performance of two IC methods, that is, unconditional IC and successive IC, in large‐scale D2D‐enabled cellular networks using the tools from stochastic geometry. To facilitate the interference analysis, we propose an approach of stochastic equivalence of the interference, which converts the two‐tier interference (interference from the cellular tier and D2D tier) to an equivalent single‐tier interference. Based on the proposed stochastic equivalence models, we derive the general expressions for the successful transmission probabilities of both cellular uplinks and D2D links in the networks where unconditional IC and successive IC are respectively applied. We demonstrate how these IC methods affect the network performance using both analytical and numerical results. Copyright © 2016 John Wiley & Sons, Ltd.

This paper considers a device-to-device (D2D) underlaying cellular network where an uplink cellular user communicates with the base station while multiple direct D2D links share the uplink spectrum. This paper proposes a random network model based on stochastic geometry and develops centralized power control algorithm. The goal of the proposed power control algorithm is two-fold: ensure the cellular users have sufficient coverage probability by limiting the interference created by underlaid D2D users, while also attempting to support as many D2D links as possible. This paper adopts the two level control strategy: Cellular link SINR(signal-to-interference-plus noise ratio) and sum rate maximization, to ensure the cellular communication and improve the coverage probability of D2D and cellular links. Numerical results show the gains of the proposed power control algorithm and accuracy of the analysis.KeywordsPower controlStochastic geometryPoisson point processCoverage probability

Effects of directional antennas on outband D2D mmWave communications in heterogeneous networks

In this paper, we propose a device-to-device (D2D) communication scheme to improve local services in cellular networks. By employing cooperative relay (CR) technology, D2D and cellular communications can operate in orthogonal resource sharing (ORS) mode with the aim of optimizing the data rates for local D2D users while fulfilling the minimum rate requirements for prioritized cellular users. In the proposed CR-based ORS scheme, we consider a cellular communication that is willing to share part of the occupied bandwidth resource with some D2D communications. Hence, the newly-obtained resource can be used by a D2D communication for the following two purposes, i.e., to compensate the rate loss of the cellular communication through cooperative relaying and to communicate its own information so as to increase its own rate. We formulated this CR-based ORS problem as a non-convex optimization problem. Hence, a global maximizer may not exist for the problem. To find the optimal solution for the problem, an effective heuristic algorithm is developed. Simulation results show that the proposed D2D communication scheme can significantly increase the rates of local D2D users and also fulfill the minimum rate requirements of cellular users.

There are many scenarios that have been proposed for fifth generation (5G) networks. Some of them, if implemented, will bring fundamental changes at the architectural and node level. One example of such proposed technologies is device-to-device (D2D) communications which will change the nature of conventional cellular network design. D2D permits direct communication between two or more user devices without intervention of the base station (i.e. eNB). D2D can ensure network performance improvement over the traditional cellular network, because it can offload the mobile data traffic from the other devices. However, applying D2D features in a cellular network will bring about more complex interference problems, since D2D communication uses the same band as its underlying cellular communication network. The aim of this research is to investigate interference-related problems caused by D2D communications, affecting the underlying cellular networks, during downlink and uplink transmissions. The paper examines the use of power control methods to mitigate interference. A comparison is offered between fixed power level (FC) with or without power control, and adaptive power controls using two methods (AC1 and AC2), on a base station or on each of the D2D devices, based on the measured signal to interference plus noise ratio (SINR). The simulation results show that both power control methods contribute to improvement of network performance. AC1 and AC2 can improve SINR by about 1 dB and 0.5 dB compared to FC in a downlink transmission, and by 0.5 dB in an uplink transmission.

Device-to-Device (D2D) communication has become an important technology in future networks, since it can provide advantages such as cell throughput enhancement, user equipment power saving, and increased instantaneous data rate. However, the performance of both D2D and cellular communication can be affected by mutual interferences between them. In this paper, we analyze a resource allocation method for D2D links underlaying cellular networks. A novel method which allows more than one D2D pair to reuse the downlink resource of one cellular user is proposed. In addition, we also present an algorithm to assign a cellular user to each group of D2D pairs, when there are a number of cellular users and D2D users. The proposed algorithm is designed to guarantee that the SINR for both the cellular link and D2D link exceeds acceptable thresholds.

Next-generation network is considered as a device-to-device (D2D)-enabled system. The overlay in-band scheme can be used by the cellular user equipments and D2D user equipments (DUEs) to send data. The cellular and D2D links experience the in-band emission interference (IEI) from the DUEs that use the adjacent frequencies. This paper models the IEI impact by using stochastic geometry and analytically investigates this impact on cellular and D2D links. The IEI inter-cell and IEI intra-cell are separately assessed, and the expected D2D resource block (DRB) reuse factor is evaluated. Furthermore, the distance-density-based strategy is proposed to mitigate the IEI by controlling the number and location of served DUEs for each DRB. Also, the optimal power allocation algorithm is proposed by calculating the optimal DUEs transmission power profile that mitigates IEI and maximizes DUEs sum rate. The performance is improved significantly for the proposed methods. The application scenario is identified for each mitigation method.

We propose a multiple-input multiple-output (MIMO) two-way relaying based underlay device-to-device (D2D) communication system, in which relay uses physical layer network coding (PNC). Both cellular and D2D communication take place in the same spectrum. D2D communication is based on PNC, and a joint transceiver design is required to facilitate PNC mapping with MIMO channels. A joint precoder-decoder scheme is also considered in the cellular communication to mitigate interference, and improve the error performance. Mean square errors at nodes are considered as the objective function, and interference threshold limits and power constraints are also used in joint precoder-decoder design problems. These turn out to be non-convex optimization problems, and we propose two algorithms in both phases of D2D and cellular communication. Distributed optimization methods are used in the proposed algorithms. We analyze the convergence of proposed algorithms, and the system performances are investigated with different D2D pair locations, interference constraint thresholds, and maximum available power at nodes.

Device-to-Device (D2D) communication underlaying cellular network is potential to enhance the spectral efficiency, reduce the energy consumption and improve individual quality-of-service (QoS) experience. But intra-cell orthogonality is impaired due to spectral reusing and severe co-channel interference could be imposed between cellular and D2D links. Besides, the direct links between local communicating pairs may be unfavorable and suffer an unsatisfied QoS experience since the randomness of channel condition. So, we are focused on analyzing the outage probability of D2D links assisted by two-way relays on Rayleigh fading channel. Specifically, we consider an amplify-and-forward relay protocol at relay due to their limited processing ability, and devise power control at both D2D transmitter and relay to maintain the QoS requirement of prioritized cellular links. The simulation results verify the correctness of the outage probability analyses for D2D links, and indicate the performance gain when relays are introduced to facilitate D2D links.

The emergence of the D2D communications paradigm has transformed the way in which cellular networks are operated. Previous work in D2D communications, however, mainly focused on interference management and capacity maximization of both D2D links and cellular links. Recent literature has observed that the QoE can be greatly enhanced by caching contents in mobile devices, with a carefully designed caching strategy. In this article, we propose a novel hypergraph framework that designs the caching based D2D communication scheme by taking social ties among users and common interests into consideration. We first present the considered features of the D2D transmission scheme, social characteristics consideration, and interest similarity impact. The key concepts of hypergraph and related techniques, such as hypergraph coloring and multidimensional matching, are explained. Then some design issues with simulation results in the proposed framework are discussed in detail, which show the potential of the proposed approach. By jointly considering social ties, common interests, and the D2D transmission scheme, we believe the proposed framework explores new opportunities and future directions in caching based socially-aware D2D communications.

One of the key features of the fifth-generation (5G) cellular network is non-orthogonal multiple access (NOMA) which improves the spectrum efficiency and increases the network connectivity. A second key ingredient is device to device (D2D) communication which increases spectrum efficiency and off-loads the cellular network. A proper exploitation of both NOMA and D2D requires adequate resources allocation algorithms to manage the interference. Moreover, to support various quality of service (QoS) requirements, other key metrics beyond the rate should be taken into account, such as queue stability and head of line (HoL) packet delay. In this paper, we consider resource block (RB) allocation and power control for both uplink NOMA and D2D communications. An overlay spectrum sharing paradigm is adopted, where an RB is exclusively allocated to either the cellular or D2D communications. The solution uses the modified largest weighted delay first (MLWDF) scheduling discipline and reduces the HoL packet delay, with negligible reduction of the achieved sum rate with respect to the pure maximum-rate solution in typical cellular scenarios.

Underlay device-to-device (D2D) communication in a cellular network is expected to improve spectrum utilization as well as to enable the use of new proximity-based applications. However, deploying D2D communications in a cellular network poses some challenges in the system design due to the potential interference between the cellular links and the D2D links. In this paper, we consider a scenario where a D2D device equipped with multiple antennas attempts to reuse the downlink resources of an active cellular user. Two strategies are proposed to handle the interference that the D2D link may cause to the cellular link. Interference nulling (IN), the first strategy, completely eliminates the interference, while interference constraining (IC), the second strategy, intends to limit the amount of residual interference such that the signal-to-interference-plus-noise ratio (SINR) for the cellular user is ensured to be higher than a certain threshold. Both methods do not produce additional overhead at the base station (BS), since the D2D side autonomously determines the transmit signals without involvement of the BS. The results of a numerical analysis are then presented to compare the performance of these two strategies under various environments.