Full-duplex D2D Communications Research Articles

Energy Efficiency Optimization for Full-Duplex D2D Communications Underlaying Distributed Antenna Systems

Energy Efficiency Optimization for Full-Duplex D2D Communications Underlaying Distributed Antenna Systems

Covert Rate Study for Full-Duplex D2D Communications Underlaid Cellular Networks

Device-to-device (D2D) communications underlaid cellular networks have emerged as a promising network architecture to provide extended coverage and high data rate for various Internet of Things (IoT) applications. However, because of the inherent openness and broadcasting nature of wireless communications, such networks face severe risks of data privacy disclosure. This paper investigates the covert communications in such networks for providing enhanced privacy protection. Specifically, this paper explores the critical covert rate performance in a full-duplex D2D communication underlaid cellular network consisting of a base station, a cellular user, a D2D pair with a transmitter and a full-duplex receiver, and a warden, where the D2D receiver can operate over either the full-duplex (FD) mode or the half-duplex (HD) mode. We first derive transmission outage probabilities of cellular and D2D links under the FD and HD modes, respectively. Based on these probabilities, we further provide theoretical modelling for the covert rate under each mode and explore the corresponding covert rate maximization by jointly optimizing the transmit powers of the D2D pair and the cellular user. To improve the covert rate performance, we propose a general mode in which the D2D receiver can flexibly switch between these two modes. Under the general mode, we also investigate the theoretical modelling and maximization problems of covert rate. Finally, we present extensive numerical results to illustrate the covert rate performances under the FD, HD, and general modes.

AI-Generated Incentive Mechanism and Full-Duplex Semantic Communications for Information Sharing

The next generation of Internet services, such as Metaverse, rely on mixed reality (MR) technology to provide immersive user experiences. However, limited computation power of MR headset-mounted devices (HMDs) hinders the deployment of such services. Therefore, we propose an efficient information-sharing scheme based on full-duplex device-to-device (D2D) semantic communications to address this issue. Our approach enables users to avoid heavy and repetitive computational tasks, such as artificial intelligence-generated content (AIGC) in the view images of all MR users. Specifically, a user can transmit the generated content and semantic information extracted from their view image to nearby users, who can then use this information to obtain the spatial matching of computation results under their view images. We analyze the performance of full-duplex D2D communications, including the achievable rate and bit error probability, by using generalized small-scale fading models. To facilitate semantic information sharing among users, we design a contract theoretic AI-generated incentive mechanism. The proposed diffusion model generates the optimal contract design, outperforming two deep reinforcement learning algorithms, i.e., proximal policy optimization and soft actor-critic algorithms. Our numerical analysis experiment proves the effectiveness of our proposed methods.

A phased resource allocation algorithm for full‐duplex device‐to‐device communications underlaying cellular networks

AbstractDevice‐to‐device (D2D) and full duplex (FD) technologies demonstrate immense potentials to improve the spectral efficiency of wireless networks. However, their synergistic combination to reap added benefits is proved to be technically challenging. This letter investigates the throughput‐maximization resource allocation problem for FD D2D communications underlaying cellular networks. The problem is decoupled into two subproblems, namely power allocation and channel assignment, which are solved by using a novel quadratic transform based scheme and the Kuhn–Munkres algorithm, respectively. Simulation results show that the proposed algorithm outperforms existing ones in terms of overall system throughput.

Secure Transmission in Wiretap Channels Using Full-Duplex Relay-Aided D2D Communications With Outdated CSI

This letter examines the physical layer security of a cellular network with inband underlay relay-aided Device-to-Device (D2D) communication, considering the scenario where the channel state information is outdated. The relay node, which operates in a full-duplex mode, can concurrently serve as a friendly jammer to enhance the cellular network secrecy performance while increasing the D2D communication data transmission. A passive eavesdropper utilizes combining approaches to combine the eavesdropping signals. Closed-form expressions for the D2D outage probability and the secrecy outage probability are derived. Furthermore, the asymptotic results are also provided.

Interference Management and Duplex Mode Selection in In-Band Full Duplex D2D Communications: A Stochastic Geometry Approach

In this article, we present a new approach for managing the interference on cellular users through optimum mode selection between half-duplex (HD) and in-band full-duplex (IBFD) in such a way that device-to-device (D2D) throughput is maximized, while the quality of service (QoS) of the cellular users is guaranteed in terms of delay. To present a comprehensive view and analyse of the proposed approach in a large network, we use Poisson point process that enables us to model a large network with random parameters in such a way that is highly compatible with reality. Also, to model the cellular users' delay, we use the queuing theory and Markov processes. Unlike other related works, the mode selection between HD and IBFD is considered as a decision variable and its optimal value is obtained. The results show that in comparison with the related works, our proposed approach leads to improvements in the D2D throughput, while through proper interference management, the impact on the cellular users' throughput is negligible. Moreover, the QoS of the cellular users is guaranteed by keeping the delay below a certain threshold.

Spectral Efficiency Improvement of Full-Duplex D2D Communication in Cellular Networks

Radio spectrum is becoming scarce due to increasing demand for high data rate, mobile communication and ever-expanding population with diverse need to always stay interconnected. The cellular network providers and researchers in the academia are continually finding innovative ways to efficiently manage the existing telecommunication infrastructure and plan effective for future expansions and technology. Device to Device (D2D) communication, Full-Duplex (FD) radio, Heterogeneous network are a few of such innovative technologies developed to face the challenges. Device to device communication is one promising technology that is studied for deployment in future network technologies, however it is not without its challenges. Various researches have been carried out and are still being carried out to better understand and improve device to device capabilities. The use of full-duplex radios is an area of study with capability for improving device to device communication due to recent development in full-duplex radio although its major drawback is limited self-interference cancellation abilities to be deployed in large transmit power system. This research presents the practicality of deploying existing FD radios in device to device communication and simulate the amount of self-interference cancellation required using MATLAB for effective use with device to device. Two interference management schemes were implemented to improve the performance of FD-D2D communication, first power control scheme was developed to mitigate interference between D2D and base station in uplink resource sharing, Interference Limited Area (ILA) method was adapted to deal with interference between D2D and cellular user Uplink and Downlink transmission. The performance between 75dB to 110dB Self-Interference (SI) cancellation was carried out. The result was compared to conventional cellular and Half-Duplex D2D communication to estimate the improvement offered on spectral efficiency. The work has improved on achieving almost 100% spectral efficiency thereby improving the Quality of Service (QoS) for cellular network

Performance Analysis and Optimization of Cooperative Full-Duplex D2D Communication Underlaying Cellular Networks

This paper investigates the cooperative full-duplex device-to-device (D2D) communication underlaying a cellular network, where the cellular user (CU) acts as a full-duplex relay to assist the D2D communication. To simultaneously support D2D relaying and uplink transmission, superposition coding and successive interference cancellation are adopted at the CU and the D2D receiver, respectively. The achievable rate region and joint outage probability are derived to characterize the performance of the considered system. In consideration of the fairness between the cellular uplink and the D2D link, an optimal power allocation scheme is proposed to maximize the minimum achievable rate of them. Besides, by analyzing the upper bound of the joint outage probability, we study a suboptimal power allocation to improve the outage performance. The simulation results confirm the theoretical analysis and the advantages of the proposed power allocation schemes.

Power Control for Full-Duplex D2D Communications Underlaying Cellular Networks

As two promising candidate techniques for the 5G mobile communication system, device-to-device (D2D) communications and full-duplex communications have drawn significant research interests. Since full-duplex communications are suitable for use in low transmit power scenarios to lower the residual self-interference (SI), while D2D communications work in short distance scenarios which result in low transmit power, it is natural to integrate full-duplex into D2D communications. In this paper, we investigate the power control for full-duplex D2D communications underlaying cellular networks. Specifically, we formulate the power control problem by maximizing the achievable sum-rate of the full-duplex D2D link while fulfilling the minimum rate requirement of the cellular link under the maximum transmit power constraint of the cellular user and D2D users. Two algorithms are proposed to solve the optimization problem. For the first algorithm, we convert the objective function into a concave function based on difference of convex (D. C.) structure and propose an iterative algorithm to solve the optimization problem. For the second algorithm, we consider the received signal-to-interference-plus-noise ratios (SINRs) at the D2D users are high. Based on high-SINR approximation, closed-form optimal solutions are obtained for different boundaries of the feasible region. Numerical results are presented to illustrate the effect of the channel gains and SI cancellation ability on the optimal transmit power and the achievable sum-rate of the full-duplex D2D link.

Joint Spectrum Partition and Performance Analysis of Full-Duplex D2D Communications in Multi-Tier Wireless Networks

Joint Spectrum Partition and Performance Analysis of Full-Duplex D2D Communications in Multi-Tier Wireless Networks

Performance Analysis of the Content Dissemination Mechanism with Proactive Content Fetching and Full-Duplex D2D Communication: an Evolutionary Perspective

Device-to-device (D2D) communication has been regarded as a promising technique for content dissemination in the fifth generation wireless network. To improve the efficiency of content dissemination, in this paper, we propose a content dissemination mechanism with proactive content fetching (PCF) and full-duplex (FD) D2D communication, referred to as PCF-FD mechanism. This mechanism is characterized by the proactive content requests of partial users that don’t request contents originally. FD communication is utilized to establish more D2D links and increase the area spectral efficiency (ASE). Based on stochastic geometry, we derive the recursive formula of content caching probability from the evolutionary perspective. In addition, the expressions of successful offloading probability (SOP), ASE and average energy consumption are also obtained. Computer experiments show that the analytical results match well with simulation results and our scheme outperforms the conventional scheme without PCF and FD communication by 45% in terms of SOP in a scenario with small user density and light load.

Power Control for Device-to-Device Communication with a Hybrid Relay Mode in Unequal Transmission Slots

Device-to-device (D2D) pairs are allowed to reuse the spectrum of cellular users who are in a good quality channel state with underlaying cellular network. However, cellular users usually suffer a poor performance in term of achievable rate when they are in a cell edge or in deep fading. To solve this problem, a hybrid relay-aided D2D communication scheme with a two-antenna infrastructure and using two unequal transmission slots is proposed in this paper. Different from the pure half-duplex and full-duplex D2D relay work, the hybrid-duplex relay mode that we propose enables the D2D relay to receive and transmit signals at the same time in the first time slot. Thus, it is similar to the full-duplex which could increase the spectrum efficiency. In addition, in the second time slot, the D2D relay will forward only the cellular user’s signals, thus avoiding the transmission of mixed signals which would deteriorate the system performance, similarly to the half-duplex mode. Moreover, by bringing in a slot splitting factor, the relay node in our hybrid-duplex mode is set to guarantee the matching of the transmission rate in two hops. We formulate the problem of maximizing the D2D transmission rate while guaranteeing in priority the minimum rate for the cellular user. By using the method of rate matching and linear programming, we deduce the expression of the slot splitting factor as well as the optimal power allocation for the base station and D2D relay, while guaranteeing the minimum rate requirement for the cellular user in a close form. The simulation results show that the proposed relay-based hybrid-duplex D2D scheme outperforms the existing half-duplex and full-duplex relay-based D2D communication schemes in term of achievable rate.

Application of interference alignment in fullduplex D2D communications

As compared with the wireless half-duplex (HD) transmission, the wireless full-duplex (FD) transmission can potentially double the system throughput if the self-interference can be efficiently cancelled. Accordingly, this paper proposed an interference alignment (IA)-based self-interference suppression method for the FD D2D bidirectional communications. The self-interference and mutual interference are aligned into the null-space at the receiver, and then suppressed by the receive matrices. Performance evaluation demonstrates the effectiveness of proposed self-interference suppression algorithm for the FD D2D networks.

Capacity Improvement for Full Duplex Device-to-Device Communications Underlaying Cellular Networks

In this paper, the capacity improvement of full-duplex (FD) device-to-device (D2D) underlaying cellular networks (CNs) is analyzed. A single-cell environment is considered with one half-duplex (HD) base station, multiple HD cellular user equipments (CUEs), and one pair of FD D2D user equipments (DUEs). The BS is equipped with ${M}$ multiple antennas, and one pair of FD DUEs is permitted to share the same resource with ${M}$ out of ${K}$ uplink HD CUEs, which will lead to a more complex interference environment. First, a novel interference-limited area-based (ILA-based) scheme is proposed to manage the co-channel interference from CN CUEs to FD DUEs. The ILA-based scheme does not allow the coexistence of HD CUEs and FD DUEs if the HD CUEs are located in any region of the two ILAs. Next, a senior ILA-based (SILA-based) scheme is proposed to reduce the complexity of the ILA-based scheme, in which only a common ILA is designed for both FD DUEs instead of the two ILAs in the ILA-based scheme. Then, the lower bounds of the ergodic capacity for FD D2D communications with imperfect self-interference cancellation (SIC) are derived in closed-forms with the ILA-based scheme and the SILA-based scheme. Furthermore, the capacity gain of the FD D2D communications is analyzed, and the numerical results show that the capacity improvement of the FD D2D communications is much greater than the traditional HD D2D communication if the sufficient SIC is achieved.

Cooperative Full Duplex Device to Device Communication Underlaying Cellular Networks

Recently, device-to-device (D2D) communication and full duplex communication are both considered key technologies for 5G networks. In this paper, two novel cooperative modes are developed for full duplex D2D communication underlaying cellular networks: the network MU-MIMO based mode (N-mode) and the sequential forwarding mode (S-mode). In the N-mode, two D2D users work as network MIMO to forward the data to cellular users and thus leverage the channel diversity. In the S-mode, the spatial distribution of D2D users and cellular users is explored to improve the transmission rate. Based on these modes, two D2D users share the downlink resources with two nearby cellular users simultaneously to achieve both proximity gain and reuse gain. Moreover, these modes are well suited for edge cellular users. To optimize the performance of the two modes, optimal power allocation is conducted by considering the influence of residual self-interference at full duplex radios and the requirements of the minimum transmission rate for both cellular users and D2D users. Simulation results show that, compared with the dedicated mode, the sum rate of cooperative modes in the perfect self-interference cancellation case can achieve 32% overall improvement and about 70% improvement in the scenario with non-edge D2D users and edge cellular users. With residual self-interference at a full duplex radio, the overall performance improvement is reduced to 15%. However, the cooperative modes can still achieve 40% improvement in the scenario with non-edge D2D users and edge cellular users.

Cooperative Game-based Cheating in Full-duplex Relaying-based D2D Communication Underlaying Heterogeneous Cellular Networks

Device-to-device (D2D) communications allow direct transmissions between two adjacent user devices, which can improve system performance in cellular networks. Considering full-duplex (FD) relaying outperforms half-duplex (HD) relaying in spectrum and energy efficiency, we apply the FD relaying-based D2D communication scheme in heterogeneous cellular network, which allows D2D links to underlay cellular downlink by assigning D2D transmitters as FD relays to assist cellular downlink transmissions. Although the scheme can improve the utilization of spectrum resource dramatically, the unreasonable resource sharing of D2D users will increase the inter-user interference. Therefore, in this paper, we try to optimize the throughput of D2D users on the premise of ensuring the quality of service (QoS) of cellular users. To this end, we first propose a D2D transmit power-allocation scheme and use Gale-Sharpley (GS) algorithm in matching theory to solve the resource allocation problem. Next, a Cheating algorithm based on cooperative game theory is proposed to further improve the throughput of D2D users. More importantly, due to the NP-hardness of finding the optimal solution of Cheating algorithm, we propose a heuristic algorithm based on depth first search (DFS) which using different colors to represent the different statements of D2D users to find a near-optimal solution. The simulation results show that the proposed algorithm compared with GS algorithm can significantly improve the total throughput of D2D users, and it also has lower complexity and better throughput performance against existing Cheating algorithm.

Outage Performance Analysis of Full-Duplex Relay-Assisted Device-to-Device Systems in Uplink Cellular Networks

This paper proposes a full-duplex cooperative device-to-device (D2D) communication system, where the relay employed can receive and transmit signals simultaneously. We adopt such a system to assist with D2D transmission. We first derive the conditional cumulative distribution function and the probability density function (pdf) of a series of channel parameters when the interference to the base station is taken into consideration and power control is applied at the D2D transmitter and the relay node. Then, we obtain an exact expression for the outage probability as an integral and as a closed-form expression for a special case, which can be used as a good approximation to the general case when residual self-interference is small. Additionally, we also investigate the power allocation problem between the source and the relay and formulate a suboptimal allocation problem, which we prove to be quasi-concave. Our analysis is verified by the Monte Carlo simulations, and a number of important features of full-duplex cooperative D2D communications can, thereby, be revealed.

Resource Allocation for Weighted Sum-Rate Maximization in Multi-User Full-Duplex Device-to-Device Communications: Approaches for Perfect and Statistical CSIs

In this paper, we investigate the resource allocation problem for multi-user full-duplex device-to-device (D2D) underlay communication, considering both perfect channel state information (CSI) and statistical CSI scenarios. In perfect CSI scenario, the weighted sum-rate maximization problem under cellular users’ minimum rate constraints is formulated as a mixed integer programming problem. To solve the challenging problem, we decouple it into two subproblems as power allocation and channel assignment. Then we proposed a power allocation algorithm based on difference of two convex functions programming and a channel assignment algorithm based on Kuhn–Munkres algorithm, respectively. In statistical CSI scenario, we formulate the resource allocation problem as an outage probability constrained weighted ergodic sum-rate maximization problem. To solve the problem, the closed-form expressions of outage probability and weighted ergodic sum-rate are derived first. Then we decouple resource allocation problem into power allocation and channel assignment. An optimization solution that consists of a 2-D global searching and Kuhn–Munkres algorithm is then developed. Simulation results demonstrate that the proposed algorithms can improve the weighted sum-rate of full-duplex D2D communications significantly both in perfect CSI and statistical CSI scenarios and confirm the accuracy of our derived closed-form expressions.

Modeling Cellular Networks With Full-Duplex D2D Communication: A Stochastic Geometry Approach

A network model is considered, where Poisson distributed base stations transmit to $N$ power-domain non-orthogonal multiple access (NOMA) users (UEs) each that employ successive interference cancellation (SIC) for decoding. We propose three models for the clustering of NOMA UEs and consider two different ordering techniques for the NOMA UEs: mean signal power-based and instantaneous signal-to-intercell-interference-and-noise-ratio-based. For each technique, we present a signal-to-interference-and-noise ratio analysis for the coverage of the typical UE. We plot the rate region for the two-user case and show that neither ordering technique is consistently superior to the other. We propose two efficient algorithms for finding a feasible resource allocation that maximize the cell sum rate $\mathcal {R}_{\mathrm{ tot}}$ , for general $N$ , constrained to: 1) a minimum throughput $\mathcal {T}$ for each UE, 2) identical throughput for all UEs. We show the existence of: 1) an optimum $N$ that maximizes the constrained $\mathcal {R}_{\mathrm{ tot}}$ given a set of network parameters and 2) a critical SIC level necessary for NOMA to outperform orthogonal multiple access. The results highlight the importance in choosing the network parameters $N$ , the constraints, and the ordering technique to balance the $\mathcal {R}_{\mathrm{ tot}}$ and fairness requirements. We also show that interference-aware UE clustering can significantly improve performance.

An Overview of Device-to-Device Communications Technology Components in METIS

As the standardization of network-assisted device-to-device (D2D) communications by the Third Generation Partnership Project progresses, the research community has started to explore the technology potential of new advanced features that will largely impact the performance of 5G networks. For 5G, D2D is becoming an integrative term of emerging technologies that take an advantage of the proximity of communicating entities in licensed and unlicensed spectra. The European 5G research project Mobile and Wireless Communication Enablers for the 2020 Information Society (METIS) has identified advanced D2D as a key enabler for a variety of 5G services, including cellular coverage extension, social proximity, and communicating vehicles. In this paper, we review the METIS D2D technology components in three key areas of proximal communications—network-assisted multi-hop, full-duplex, and multi-antenna D2D communications—and argue that the advantages of properly combining cellular and ad hoc technologies help to meet the challenges of the information society beyond 2020.