D2D User Equipments Research Articles

Enabling Asynchronous Machine-Type D2D Communication Using Multiple Waveforms in 5G

In this paper, we explore the idea that 5G will permit the use of multiple waveforms, with each service employing a waveform that is best suited for it. We look at a 5G machine-type communication (MTC) scenario consisting of clustered user equipment employing device-to-device (D2D) communication, such as a smart factory with intercommunicating machinery. The overhead associated with synchronizing a large number of machine-type D2D user equipment (DUE) comes at a cost that may render synchronous communication infeasible or undesirable. Based on this motivation, we consider multiple possible combinations of prominent 5G waveform candidates for cellular users and DUEs, examining the asynchronous performance of all waveforms under consideration and using the performance of synchronous orthogonal frequency division multiplexing (OFDM) as a baseline for comparison. Specifically, we focus on the coexistence of waveforms in which the ordinary cellular users employ OFDM for synchronous communication, as in LTE, and the machine-type DUEs, operating asynchronously, employ a different waveform. When DUEs employ filter bank multicarrier with offset-QAM, the average achieved rate is marginally greater than the synchronous OFDM baseline case, and approximately 43% greater than the asynchronous OFDM case. This result is encouraging, as the benefits of asynchronous D2D communication could be enjoyed in MTC scenarios without suffering any performance reduction compared to the synchronous OFDM scenario. We then investigate how the relative performance of different waveform choices depends on the scenario by varying key parameters. Notably, for asynchronous communication, increasing the transmit power of DUEs results in diminishing benefits unless the DUEs employ a waveform that mitigates interdevice leakage interference.

Cooperative Willingness Aware Collaborative Caching Mechanism Towards Cellular D2D Communication

In D2D communication, physically adjacent users can directly establish connections without transmitting through base station, which can improve the network performance. The cellular D2D caching technology can offload part of the traffic of the base station and effectively alleviate the data transmission pressure of the base station. However, there is no research on cache mechanism in cellular D2D network that consider the collaboration willingness of equipment (UE). Therefore, the cooperative willingness aware collaborative caching mechanism towards cellular D2D communication (CWCM) is proposed. First, a D2D UE cache capability estimation method is proposed, which comprehensively considers the cache space occupied by the local cache content and the actual cache space setting of the UE to estimate the cache capability of the UE. Second, a D2D UE service relationship perception method is presented in which the content cache and the content discard records are used to comprehensively consider the cooperative and non-cooperative behavior to sense the service relationship between D2D UEs. Third, a collaborative willingness awareness caching mechanism is designed by considering the cache capability of the UE and the service relationship between the UEs. Simulation results show that the proposed CWCM can greatly improve the cache hit rate, largely reduce the transmission energy consumption, and average delay.

A Distributed Mode Selection Approach Based on Evolutionary Game for Device-to-Device Communications

As one of the key technologies for the fifth generation (5G) mobile networks, device-to-device (D2D) communications offer promising benefits such as high spectrum efficiency, traffic offloading, and enhanced coverage. Depending on the resource sharing between D2D users and regular cellular users, a D2D user equipment (UE) can dynamically switch its communication mode to improve the quality of service (QoS) and user experience. Mode selection is an essential issue to ensure the QoS of D2D UEs while maximizing the system capacity. In this paper, we investigate the D2D mode selection problem from a novel perspective. In addition to the classic cellular mode and direct reuse mode, we further consider a relay mode for D2D UEs. Moreover, in order to address a potentially large population of D2D UEs, we propose an evolutionary game-based approach for D2D mode selection. The evolutionary game is formulated with a utility function that takes into account both the achievable throughput of D2D UEs and the radio resource consumption. Based on the evolutionary game formulation, we implement selection dynamics, i.e., replication by imitation, in a device-controlled mode selection algorithm. To evaluate the performance of the proposed mode selection algorithm, we conduct simulations to compare it with three baseline schemes, including an approach based on maximum signal-to-interference-plus-noise, a distance-based approach, and a random approach. As shown in the simulation results, the proposed approach achieves higher utilities than the baseline schemes.

Channel Access and Power Control for Mobile Crowdsourcing in Device‐to‐Device Underlaid Cellular Networks

With the access of a myriad of smart handheld devices in cellular networks, mobile crowdsourcing becomes increasingly popular, which can leverage omnipresent mobile devices to promote the complicated crowdsourcing tasks. Device‐to‐device (D2D) communication is highly desired in mobile crowdsourcing when cellular communications are costly. The D2D cellular network is more preferable for mobile crowdsourcing than conventional cellular network. Therefore, this paper addresses the channel access and power control problem in the D2D underlaid cellular networks. We propose a novel semidistributed network‐assisted power and a channel access control scheme for D2D user equipment (DUE) pieces. It can control the interference from DUE pieces to the cellular user accurately and has low information feedback overhead. For the proposed scheme, the stochastic geometry tool is employed and analytic expressions are derived for the coverage probabilities of both the cellular link and D2D links. We analyze the impact of key system parameters on the proposed scheme. The Pareto optimal access threshold maximizing the total area spectral efficiency is obtained. Unlike the existing works, the performances of the cellular link and D2D links are both considered. Simulation results show that the proposed method can improve the total area spectral efficiency significantly compared to existing schemes.

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.

Throughput-Aware Cooperative Reinforcement Learning for Adaptive Resource Allocation in Device-to-Device Communication

Device-to-device (D2D) communication is an essential feature for the future cellular networks as it increases spectrum efficiency by reusing resources between cellular and D2D users. However, the performance of the overall system can degrade if there is no proper control over interferences produced by the D2D users. Efficient resource allocation among D2D User equipments (UE) in a cellular network is desirable since it helps to provide a suitable interference management system. In this paper, we propose a cooperative reinforcement learning algorithm for adaptive resource allocation, which contributes to improving system throughput. In order to avoid selfish devices, which try to increase the throughput independently, we consider cooperation between devices as promising approach to significantly improve the overall system throughput. We impose cooperation by sharing the value function/learned policies between devices and incorporating a neighboring factor. We incorporate the set of states with the appropriate number of system-defined variables, which increases the observation space and consequently improves the accuracy of the learning algorithm. Finally, we compare our work with existing distributed reinforcement learning and random allocation of resources. Simulation results show that the proposed resource allocation algorithm outperforms both existing methods while varying the number of D2D users and transmission power in terms of overall system throughput, as well as D2D throughput by proper Resource block (RB)-power level combination with fairness measure and improving the Quality of service (QoS) by efficient controlling of the interference level.

Wireless powered D2D communications underlying cellular networks: design and performance of the extended coverage

ABSTRACTBecause of the short battery life of user equipments (UEs), and the requirements for better quality of service have been more demanding, energy efficiency (EE) has emerged to be important in device-to-device (D2D) communications. In this paper, we consider a scenario, in which D2D UEs in a half-duplex decode-and-forward cognitive D2D communication underlying a traditional cellular network harvest energy and communicate with each other by using the spectrum allocated by the base station (BS). In order to develop a practical design, we achieve the optimal time switching (TS) ratio for energy harvesting. Besides that, we derive closed-form expressions for outage probability, sum-bit error rate, average EE and instantaneous rate by considering the scenario when installing the BS near UEs or far from the UEs. Two communication types are enabled by TS-based protocol. Our numerical and simulation results prove that the data rate of the D2D communication can be significantly enhanced.

Mode Selection, Radio Resource Allocation, and Power Coordination in D2D Communications

D2D communication is an effective approach for traffic offloading in future cellular systems. However, only using direct D2D communication is not enough to fully exploit the advantages of D2D communications due to long distances or poor link quality between source and destination D2D UEs. This work aims to enhance the traffic offloading capacity of cellular-assisted D2D communication, taking into account D2D relays. In particular, we propose a unified model for D2D communication, in which two other D2D communication modes, that is, relay-assisted D2D and local route based D2D, are also supported by UEs in addition to direct D2D mode. We design radio protocol architectures for the three D2D modes and propose an eNB scheduling algorithm, which enables the eNB to perform joint scheduling on mode selection, radio resource allocation, and power coordination for all D2D pairs in each subframe. The effectiveness of our designs is validated by simulations.

An Interference Mitigation Scheme of Device-to-Device Communications for Sensor Networks Underlying LTE-A.

Device-to-Device (D2D) communication technology has become a key factor in wireless sensor networks to form autonomous communication links among sensor nodes. Many research results for D2D have been presented to resolve different technical issues of D2D. Nevertheless, the previous works have not resolved the shortage of data rate and limited coverage of wireless sensor networks. Due to bandwidth shortages and limited communication coverage, 3rd Generation Partnership Project (3GPP) has introduced a new Device-to-Device (D2D) communication technique underlying cellular networks, which can improve spectral efficiencies by enabling the direct communication of devices in proximity without passing through enhanced-NodeB (eNB). However, to enable D2D communication in a cellular network presents a challenge with regard to radio resource management since D2D links reuse the uplink radio resources of cellular users and it can cause interference to the receiving channels of D2D user equipment (DUE). In this paper, a hybrid mechanism is proposed that uses Fractional Frequency Reuse (FFR) and Almost Blank Sub-frame (ABS) schemes to handle inter-cell interference caused by cellular user equipments (CUEs) to D2D receivers (DUE-Rxs), reusing the same resources at the cell edge area. In our case, DUE-Rxs are considered as victim nodes and CUEs as aggressor nodes, since our primary target is to minimize inter-cell interference in order to increase the signal to interference and noise ratio (SINR) of the target DUE-Rx at the cell edge area. The numerical results show that the interference level of the target D2D receiver (DUE-Rx) decreases significantly compared to the conventional FFR at the cell edge. In addition, the system throughput of the proposed scheme can be increased up to 60% compared to the conventional FFR.

Joint mode selection and resource allocation in D2D communication based underlaying cellular networks

Device-to-Device (D2D) communication technology, under the standardization of third generation partnership project and a component of the evolving fifth generation architecture, is mainly aimed to increase system capacity and data rate via providing direct communications between end devices without the use of routing data through the network. Apart from the attracting features, due to the resource sharing between cellular user equipment (CUE) and D2D user equipment (DUE) in such communications, an efficient algorithm for resource and power allocation to DUE, especially for mobile users is necessary to maintain the performance. The current paper introduces a joint mode algorithm for mobile user to choose between cellular and D2D communications and thereby, analyzes resource allocation issues. We propose an efficient algorithm for mobility management of users based on their current connection modes. The locations of D2D pairs are estimated by Levenberg–Marquardt method based on the received signal strength (RSS) from different macrocells. Since the range of D2D communication is much shorter than that of cellular communication, in order to prevent ping-pong handoffs between cellular and D2D modes, we propose the estimation of the next RSS samples in cellular mode prior to switching to D2D mode. In both cellular and D2D modes, the allocated resource block (RB) is the one with the highest signal to interference plus noise ratio (SINR) in order to increase the throughput, under the condition of providing minimum SINR requirement of CUE. This is achieved via transmission power control of the D2D pair. For performance evaluation, we studied the effects of increasing velocity of D2D and cellular users, number of users, and SINR threshold. The results indicate that the proposed solution fairly manages the communication mode of mobile users and incurs improvement in system throughput.

Resource allocation, interference management, and mode selection in device‐to‐device communication: A survey

AbstractFor us to meet the demands of fifth generation technologies, device‐to‐device (D2D) communication is foreseen to be an important part of fifth generation networks. Device‐to‐device communication brings significant improvement in user's throughput, battery life, communication delay, and resource usage. Device‐to‐device links share the same resource with the cellular links that results in interference between cellular users and D2D user equipments. This interference can be managed by suitable resource allocation algorithms. The selection of D2D or cellular communication mode is also a hot research issue. Many research works are available in literature on the aforementioned issues regarding D2D communication, but there is no survey available in the literature. To facilitate the researchers, we present a detailed and systematic survey on resource allocation, interference management, and mode selection in D2D communication in this paper. Initially, the taxonomy based overview of D2D communication is provided, and the classification of the works is outlined. Then, the works regarding mode selection are reviewed in detail. Furthermore, interference management schemes to handle the interference caused by the underlying nature are also surveyed. Then, the available literature on resource allocation schemes in D2D perspective are presented. Finally, some open research problems are identified that deserve further research.

Joint channel selection and optimal power allocation for multi‐cell D2D communications underlaying cellular networks

Device-to-device (D2D) communication underlaying cellular networks can improve the spectrum efficiency as a result of sharing the radio resources allocated to cellular user equipments (CUEs). However, the severe interference between D2D and CUEs communications may lead to performance degradation of cellular system if not coordinated properly. In this study, a joint channel assignment and power allocation algorithm is proposed, which addresses the intra-cell and inter-cell interference management problems for D2D communication underlaying cellular network. The case of multiple D2D-user equipments (DUEs) sharing the same channel while each DUE can reuse multiple channels is considered. The proposed algorithm is designed with two complementary steps in such a way that its computational complexity can be adapted according to the network condition. The preliminary set of CUEs candidate channels that can be reused by each DUE is adaptively decided in the first step. In the second step, the optimal power allocation for each DUE is determined using Lagrangian dual decomposition to maximise the network sum-rate. Simulation results show that the proposed algorithm outperforms the current comparable algorithms especially in terms of achievable throughput. Moreover, the effect of various system parameters on the performance of the proposed technique is also investigated.

Resource Allocation for D2D Communications Underlay in Rayleigh Fading Channels

Device-to-device (D2D) communication has attracted substantial research attention recently, due to its potential to improve coverage, spectrum efficiency, and energy efficiency within the existing cellular infrastructure. One major challenge for spectrum resource sharing in D2D underlay lies in the mutual interference between cellular user equipments (CUEs) and D2D user equipments (DUEs). Considering this mutual interference constraint, this work investigates the problem of optimal matching of D2D links and CUEs to form spectrum-sharing partners to maximize ergodic sum rates under transmit power and outage constraints. Unlike previous works, full channel-state information (CSI) is not required. To solve the resulting high-complexity problem, candidate DUE sets are first narrowed down according to required outage probability constraints, which are used to construct a simplified bipartite graph. The weight of the bipartite graph is characterized as the maximization of ergodic sum rate of the associated D2D and cellular links under outage constraints for which a low-complexity algorithm is proposed to solve the nonconvex problem. After constructing the bipartite graph, the Hungarian algorithm is used to determine the optimal pairing between D2D links and CUEs. Numerical results demonstrate that the proposed algorithm can improve the outage-constrained spectrum efficiency of D2D networks with practical complexity.

Mathematical Characteristics of Uplink and Downlink Interference Regions in D2D Communications Underlaying Cellular Networks

In this paper, mathematical characteristics of uplink and downlink interference regions in device-to-device (D2D) communications underlaying cellular networks are analyzed. We consider that one CUE and one pair of D2D user equipments (DUEs) coexist and share uplink and downlink resources of cellular networks. The DUE pair consists of a D2D transmitting user equipment and a D2D receiving user equipment. Therefore, additional interference between the CUE and the DUE pair is introduced. First, uplink and downlink interference regions are defined and described. Next, mathematical characteristics of uplink and downlink interference regions are derived. Finally, blocking probability is formulated based on the mathematical characteristics values. The analysis results show that uplink resources are more suitable to be shared for the CUE and the DUE pair, but the difference between uplink and downlink is not significant. Meanwhile, the simulation results show that theoretical values of blocking probability well match simulation results. The results can provide a theoretical foundation for resource allocation and optimization of D2D communications.

Joint Opportunistic Scheduling of Cellular and Device-to-Device Communications

The joint scheduling of cellular and D2D communications to share the same radio resource is a complex task. In one hand, D2D links provide very high throughputs. In the other hand, the intra-cell interference they cause impacts on the performance of cellular communications. Therefore, designing algorithms and mechanisms that allow an efficient reuse of resources by the D2D links with a reduced impact on cellular communications is a key problem. In general, traditional Radio Resource Management (RRM) schemes (D2D grouping and mode selection) focus on finding the most compatible D2D pair for an already scheduled cellular User Equipment (UE). However, such approach limits the number of possible combinations to form the group (composed by a cellular UE and a D2D pair) to be scheduled in the radio resource. To overcome that, in this work a unified Joint Opportunistic Scheduling (JOS) of cellular and D2D communications, which is able to improve the total system throughput by exploiting the spatial compatibility among cellular and D2D UEs, is proposed. But more complexity is brought to the scheduling problem. Thus, a low-complexity suboptimal heuristic Joint Opportunistic Assignment and Scheduling (JOAS) is also elaborated. Results show that it is possible to reduce the computational complexity but still improve the overall performance in terms of cellular fairness and total system throughput with less impact on cellular communications.

Resource Allocation and Interference Management for D2D-Enabled DL/UL Decoupled Het-Nets

In this paper, resource allocation and interference mitigation are investigated for heterogeneous networks where the lowest tier consists of device-to-device (D2D) cells. In order to alleviate dead-zone problem, we first consider downlink/uplink (DL/UL) decoupling user association and quantify its capability on interference management and network-wide D2D performance enhancement. Second, we propose an UL fractional frequency reuse scheme where subband (SB) bandwidths are adaptively determined based on: 1) user equipment (UE) density; 2) e-node-B (eNB) density; and 3) on/off switching frequency of small cells. Obtained results show that the adaptive method significantly reduces the number of outage users. Thereafter, a novel concatenated bi-partite matching (CBM) method is proposed for joint SB assignment (SA) and resource block allocation (RA) of cellular UEs. Numerical results show that the CBM provides a close performance to exhaustive solution with greatly reduced running time. The CBM is then extended to a centralized mode selection, SA, and RA for D2D cells. Alternatively, we develop offline and online semi-distributed approaches where a D2D-cell can reuse white-list RBs (WRBs), which are not occupied by the adjacent small cells. In the former, D2D-cell members are not aware of intra-cell and inter-cell interference and uniformly distribute their maximum permissible power to WRBs. In the latter, we put D2D sum rate maximization into a convex form by exploiting the proximity gain of D2D UEs. Online distributed solution is then developed by message passing of dual variables and consistency prices. Finally, virtues and drawbacks of the developed approaches are compared and explained.

Resource allocation and power control for underlay device-to-device communication in fractional frequency reuse cellular networks

The current state of device-to-device (D2D) communication in the presence of cellular network addresses two major challenges of interference as well as throughput inadequacy. Specifically, a D2D communication underlaying fractional frequency reuse (FFR) cellular network exhibits rather high interferences due to higher occurrence of band crossing within a shared spectrum. However, due to the considerable impact of D2D communications on spectral efficiency and system capacity, the remedy for those issues may include efficient techniques of interference mitigation and average spectral efficiency maximization. In this paper, we propose a resource block (RB) allocation scheme to reduce the co-channel interference by providing and maintaining adequate distance between D2D user equipment (DUE) and cellular user equipment (CUE), and between the macrocell base station and DUEs that are using the same RB. In the proposed scheme, we initially introduce a plan with one omnidirectional and three directional antennas be used to serve the CUE in the inner and outer regions of the FFR cell, respectively. In addition, DUE in each region uses the RBs that are orthogonal to those used by CUE. It is shown that by using two different ranges for inner region of cellular and D2D communication, the overall performance is improved. Furthermore, we formulate an optimization problem for maximizing average spectral efficiency while guaranteeing CUE signal-to-interference-plus-noise-ratio and achieve efficient solutions to the different average spectral efficiency maximization problems. The results demonstrate the efficiency of the proposed scheme. In addition, it is shown that significant improvement in system spectral efficiency is obtained through the optimization of DUE power. That is, the achieved throughput is much higher than that of the random resource allocation and 1.5–2 times of the previous works.

Joint relay selection and resource allocation in cooperative device-to-device communications

Device-to-device (D2D) communications allow proximate cellular user equipments (UEs) to communicate with each other directly under the control of base station (BS). In this paper, considering the selection relaying (SR) rule which allows a subset of potential relays to forward the source’s data to the corresponding destination, we first establish a multi-relay system model where a D2D UE can act as not only a source but also a potential relay for another D2D link, and then analyze the cooperation behaviors among selfish UEs. Next a simple strategy is proposed to deal with the relay selection problem, and then the fair and efficient resource sharing problem among cooperating D2D UEs is formulated as a bargaining game. Since the game function is non-convex, we turn to an iterative method by introducing an auxiliary function to get the proportional fair resource allocation results. The system efficiency and fairness are proved by numeral simulation results.

Interference Cancellation and Adaptive Demodulation Mapping Schemes for Device-to-Device Multicast Uplink Underlaying Cellular Networks

Device-to-device multicast (D2MD) communications enable dissemination of messages directly from one user equipment (UE) to a group of D2D UEs (DUEs) located in close proximity, instead of routing via the base station. The challenges of D2MD arise from the interference to and from in-band cellular UEs (CUEs) due to frequency reuse, and the low data transmission rate constrained by the worst channel quality. To improve the overall system capacity, a novel interference coordination scheme and an adaptive demodulation mapping scheme (ADMS) based on rateless encoding technique is proposed. Firstly, a new interference limited area control scheme that reduces the interference from CUEs to each DUE is proposed. In the proposed scheme, the DUEs share same resource with the CUEs out of the interference limited area. Secondly, the ADMS working principle is described. In ADMS, the bits are modulated by a high level modulation and coding scheme (MCS), and each DUE can adaptively select one MCS level to demodulate bits according to the channel state information. Finally, the expressions of two performance metrics are derived, namely D2MD system delay and energy consumption, and a distance minimization problem (DMP) with attenuation function to achieve the tradeoff between the two metrics is formulated. From the simulation results, it is confirmed that the proposed schemes improve the performance of the hybrid system compared to the conventional ways. In addition, by controlling the introduced parameter, DMP can balance the tradeoff between the two metrics effectively.

Resource allocation and dynamic power control for D2D communication underlaying uplink multi-cell networks

Underlaying device-to-device (D2D) communication is suggested as a promising technology for the next generation cellular networks (5G), where users in close proximity can transmit directly to one another bypassing the base station. However, when D2D communications underlay cellular networks, the potential gain from resource sharing is highly determined by how the interference is managed. In order to mitigate the resource reuse interference between D2D user equipment and cellular user equipment in a multi-cell environment, we propose a resource allocation scheme and dynamic power control for D2D communication underlaying uplink cellular network. Specifically, by introducing the fractional frequency reuse (FFR) principle into the multi-cell architecture, we divide the cellular network into inner region and outer region. Combined with resource partition method, we then formulate the optimization problem so as to maximize the total throughput. However, due to the coupled relationship between resource allocation and power control scheme, the optimization problem is NP-hard and combinational. In order to minimize the interference caused by D2D spectrum reuse, we solve the overall throughput optimization problem by dividing the original problem into two sub-problems. We first propose a heuristic resource pairing algorithm based on overall interference minimization. Then with reference to uplink fractional power control (FPC), a dynamic power control method is proposed. By introducing the interference constraint, we use a lower bound of throughput as a cost function and solve the optimal power allocation problem based on dual Lagrangian decomposition method. Simulation results demonstrate that the proposed algorithm achieves efficient performance compared with existing methods.