Power Control For D2D Communications Research Articles

Resource Allocation and Power Control for D2D Communications With Spread Unsent-Data Strategy

Direct-to-direct (D2D) communication is a promising technology to increase the capacity of cellular networks. By D2D technology, user equipments (UEs) in a D2D group can communicate with each other without the help of a base station (BS). According to 3GPP specifications, a D2D transmitter will be assigned to radio resource blocks (RBs) based on the amount of its unsent data, say <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$D$</tex-math></inline-formula> bits, observed at the scheduling time instant. When scheduling, most previous methods assign fewer (or say just enough) RBs to consume those <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$D$</tex-math></inline-formula> bits of the D2D transmitter. By this policy, each of the assigned RBs has to carry more data bits, and the D2D transmitter needs to enlarge its transmit power on the assigned RBs. So, the D2D transmitter will induce more interference to its nearby D2D groups and may cause those nearby groups to be unschedulable. To tackle the above problem, we propose a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">spread unsent-data strategy</i> , which distributes the observed unsent data of a D2D transmitter (e.g., those <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$D$</tex-math></inline-formula> bits above) to more usable RBs. Since each RB carries fewer data bits, the D2D transmitter can reduce its transmit power. As a result, this strategy can offer the benefits of reducing interference and increasing concurrent D2D transmissions. In this work, we design a two-phase scheduling method, named <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$DS^{2}$</tex-math></inline-formula> , to accomplish the strategy. In <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$DS^{2}$</tex-math></inline-formula> , the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">preparing phase</i> first identifies usable RBs for D2D groups, and then the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">power level decision phase</i> carefully adjusts D2D transmitters' transmit power levels by considering interference relationships between the BS, cellular UEs, and D2D groups. The simulation results indicate that the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$DS^{2}$</tex-math></inline-formula> can indeed increase D2D throughput.

Distance Based Power Control for D2D Communication in LTE-Advanced Networks

Device to device communication systems places a very important role in handling both voice and data services efficiently in LTE-A networks. Power control techniques that we adopt for efficient D2D communication becomes a challenging issue. D2D and cellular signals under the same network may result in In-band Emission Interference (IEI). This degrades discovery range which result in loss of energy efficiency, throughput and hence increases the power requirement in both uplink and downlink transmissions. In this paper, a power control algorithm is introduced which greatly helps in saving power in LTE-Advanced networks for D2D communication. Power calculation mechanisms for D2D users and cellular users are shown separately. Based on mode selection, transmit and receive power requirements are evaluated to obtain the preset Quality of Service (QoS) parameters. The simulation results presented in the proposed method demonstrates the effectiveness of power consumption in LTE-Advanced networks for device to device communication.

Joint resource allocation and power control for D2D communication with deep reinforcement learning in MCC

Mission-critical communication (MCC) is one of the main goals in 5G, which can leverage multiple device-to-device (D2D) connections to enhance reliability for mission-critical communication. In MCC, D2D users can reuses the non-orthogonal wireless resources of cellular users without a base station (BS). Meanwhile, the D2D users will generate co-channel interference to cellular users and hence affect their quality-of-service (QoS). To comprehensively improve the user experience, we proposed a novel approach, which embraces resource allocation and power control along with Deep Reinforcement Learning (DRL). In this paper, multiple procedures are carefully designed to assist in developing our proposal. As a starter, a scenario with multiple D2D pairs and cellular users in a cell will be modeled; followed by the analysis of issues pertaining to resource allocation and power control as well as the formulation of our optimization goal; and finally, a DRL method based on spectrum allocation strategy will be created, which can ensure D2D users to obtain the sufficient resource for their QoS improvement. With the resource data provided, which D2D users capture by interacting with surroundings, the DRL method can help the D2D users autonomously selecting an available channel and power to maximize system capacity and spectrum efficiency while minimizing interference to cellular users. Experimental results show that our learning method performs well to improve resource allocation and power control significantly.

Outage-Optimal and Suboptimal Power Control for D2D Communications in SWIPT Cellular Networks With Local CSI

In this letter, we consider a downlink cellular network where a cellular user (CU) not only decodes information but also harvests energy. By reusing the spectrum resource of the CU, a device-to-device (D2D) transmitter sends its own signals to a D2D receiver. In order to protect the CU from the interference due to the D2D signals, we propose transmit power control schemes for the D2D transmission without increasing the outage probability of the CU. This is possible since the CU’s information loss due to the D2D signals can be compensated by the CU’s energy harvesting gain from the D2D signals. For asymptotic performance analysis, we provide a lower bound on the D2D outage probability. The numerical results show that the proposed schemes outperform the conventional scheme.

Channel, Mode and Power Optimization for Non-Orthogonal D2D Communications: A Hybrid Approach

The increasing traffic demand in cellular networks has recently led to the investigation of new strategies to save precious resources like spectrum and energy. Direct device-to-device (D2D) communication becomes a promising solution if the two terminals are located in close proximity. In this case, the D2D communications should coexist with cellular transmissions, so they must be carefully scheduled in order to avoid harmful interference impacts. In this paper, we outline a novel framework encompassing channel allocation, mode selection and power control for D2D communications. Power allocation is done in a distributed and cognitive fashion at the beginning of each time slot, based on local information, while channel/mode selection is performed in a centralized manner only at the beginning of an epoch, a time interval including a series of subsequent time slots. This hybrid approach guarantees an effective tradeoff between overhead and adaptivity. We analyze in depth the distributed power allocation mechanism, and we state a theorem which allows to derive the optimal power allocation strategy and to compute the corresponding throughput. Extensive simulations confirm the benefits granted by our approach, when compared with state-of-the-art distributed schemes, in terms of throughput and fairness.

Coalition Game-Based Strategy for Resource Allocation and Transmit Power Control in D2D Communication

Resource allocation and co-channel interference are the two major technical challenges in the implementation of device-to-device communication technology. We propose an innovative resource allocation strategy along with dynamic power control for D2D communication. The resource allocation problem is formulated as a single utility function for multiple D2D pairs and cellular users in underlaying cellular networks. The proposed strategy based on overlapping coalition formation game allows a D2D pair to reuse multiple resource blocks. It aims to maximize the system sum rate maintaining minimal adverse impact of the interference on the overall system performance. Numerical results obtained through computer simulation show that the proposed strategy significantly improves the system sum rate along with reduced power consumption.

Distributed vs centralized game theory-based mode selection and power control for D2D communications

The exponential growth cellular networks traffic has driven academia and industry to consider new channel access methods in addition to the conventional infrastructure-based access via cellular nodes. Long-Term Evolution-Advanced (LTE-A) techniques are suggested by the 3rd generation partnership project (3GPP), in order to offer both higher spectrum efficiency and data rate. In fact, LTE-A has attracted a great attention in the cellular domain, since it improves the LTE by proposing a lot of variety in terms of new techniques such as carrier aggregation, multiple-input multiple-output (MIMO), device-to-device (D2D) communications, etc. Notably, D2D communications underlaid offer several advantages for the LTE-A, as wireless peer-to-peer services and higher spectral efficiency. In LTE-A, the power control and resource allocation algorithms can generally be categorized into two classes: centralized and distributed approaches. In fact, power control and resource allocation are performed by the base station in centralized approach and by the UEs in distributed one.In this investigation, we propose first a mode selection approach based on a predetermined SINR threshold, which is required by each kind of user: cellular and D2D users. The amount of minimum and maximum power are then derived to fulfill the predetermined requirements, by limiting the interference created by underlaid D2D users. Unlike the previous works, this paper provides a mathematical demonstration to achieve the minimum amount of power (Pareto power), which satisfies the requirements imposed by both users. Second, a centralized power control approach, which aims to generalize a classical approach for more than one cellular user is proposed. Third, a distributed power control approach is modeled as a non-cooperative pure game between the different types of users in order to maximize the two cellular and D2D utility functions. Finally, these proposed centralized and distributed power control approaches are compared with a classical centralized one, in terms of coverage probabilities for both cellular and D2D users.

Adaptive Power Control for D2D Communications in Downlink SWIPT Networks With Partial CSI

In this letter, we consider the device-to-device (D2D) communication in downlink cellular networks, where the cellular user (CU) both decodes information and harvests the energy. Unlike the conventional D2D communications, we figure out that it is possible for the D2D pair to communicate without degrading the performance of the CU. Based on this observation, D2D transmit power control schemes are proposed for D2D rate maximization subject to maintaining the CU performance. In a decentralized way, the proposed power control schemes are performed at the D2D transmitter (DT) with instantaneous channel state information (CSI) of only the link between the D2D pair. For performance analysis, an asymptotic upper bound is provided on the D2D rates of the proposed schemes. Numerical results confirm the effectiveness of the proposed schemes.

Resource Allocation and Power Control for D2D Communications to Prolong the Overall System Survival Time of Mobile Cells

Device-to-device (D2D) communications as an underlay to cellular networks can potentially improve the system throughput and reduce transmission delays between users, which, however, are largely limited by the battery lifetime of user equipment (UE). In this paper, we define the overall system survival time of a mobile cell and maximize it by jointly optimizing the resource allocation and power control (RAPC) for D2D and conventional cellular links. Considering that the UEs may have different levels of residual battery energy, we define the overall system survival time as the minimally expected battery lifetime among all transmitting UEs in a cell. Subject to the transmission rate requirement of each link, we formulate the joint optimization of RAPC as a non-linear programming problem, which is NP-hard. To solve it, we devise a game theory based distributed approach, where the links are considered as non-cooperative players with the overall system survival time as their utility function. We prove the existence of the Nash equilibrium in our RAPC game and propose a low-complexity algorithm to calculate each individual player's best response, given the strategies of other players. Numerical results show that our game theory based approach can significantly prolong the overall system survival time as compared with existing RAPC schemes.

Resource Allocation and Power Control for D2D Communication Underlaying LTE-Advanced Networks

Device-to-device (D2D) communications has proven to be efficient in improving the network performance and releasing the traffic load of base station. D2D user equipment(DUEs) can share the same LTE resources blocks with the cellular user equipment(CUEs), but it would cause severe co-channel interference. In this paper, a resource allocation and power control scheme is proposed to reduce the impact of co-channel interference. First, adopt a resource allocation scheme based on greedy algorithm on the premise of meeting the minimum rate requirements of devices, then the path loss compensation factor matrix could be calculated according to the distance between DUEs to the base station and CUEs and used to reduce the influence. Simulation results show that the proposed algorithm has better performance in D2D user access rate and system throughput.

Uplink resource allocation and power control for D2D communications underlaying multi-cell mobile networks

Proximity user equipments (UEs) in mobile networks may be communicated directly without passing their traffic through the base station by using device-to-device (D2D) communications. This can be done using the underlaying approach in which the D2D-UEs (DEs) are allowed to use the same resources allocated for cellular UEs (CEs), which can enhance the spectral efficiency. However, if the resource allocation for DEs is not designed appropriately, it would generate harmful interference on CEs communications. Therefore, this paper addresses a resource allocation and power control problems for D2D communications underlaying multi-cell mobile networks with the consideration of the inter-cell and intra-cell interferences. The problem is formulated to maximise the network performance in terms of achieved throughput while ensuring the quality-of-service (QoS) constraints for CEs and DEs. A two-step algorithm is proposed in which the admission control is performed firstly to determine the set of possible D2D connections and their CE partners that achieve the minimum QoS demands. Then, the optimal power for each permissible DE and its possible partners in different cells are allocated to maximise the network throughput. Simulation results illustrate that the suggested algorithm can remarkably enhance the performance of the network in terms of throughput gain and access rate.

Delay-Aware Power Control for D2D Communication With Successive Interference Cancellation and Hybrid Energy Source

We investigate joint flow control, successive interference cancellation (SIC) scheduling, and power control design for delay-aware device-to-device communication in a multi-cell network with hybrid energy source. Aiming to maximize the time-average total throughput of network, we propose a flow control scheme and a two-stage SIC-based power control strategy based on perturbed Lyapunov optimization and sequential convex programming, subject to the SIC feasibility, queueing stability, finite energy storage, and energy balance. Simulation results exhibit the superiority of our proposed strategy against alternative strategies.

Game Theory Based Interference Control and Power Control for D2D Communication in Cellualar Networks

Game Theory Based Interference Control and Power Control for D2D Communication in Cellualar Networks

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.

Energy-Efficient Joint Resource Allocation and Power Control for D2D Communications

In this paper, joint resource allocation and power control for energy-efficient device-to-device (D2D) communications underlaying cellular networks are investigated. The resource and power are optimized for maximization of the energy efficiency (EE) of D2D communications. Exploiting the properties of fractional programming, we transform the original nonconvex optimization problem in fractional form into an equivalent optimization problem in subtractive form. Then, an efficient iterative resource allocation and power control scheme is proposed. In each iteration, part of the constraints of the EE optimization problem are removed by exploiting the penalty function approach. We further propose a novel two-layer approach, which allows finding the optimum at each iteration by decoupling the EE optimization problem of joint resource allocation and power control into two separate steps. In the first layer, the optimal power values are obtained by solving a series of maximization problems through root finding, with or without considering the loss of cellular users' rates. In the second layer, the formulated optimization problem belongs to a classical resource-allocation problem with single allocation format, which admits a network flow formulation so that it can be solved to optimality. Simulation results demonstrate the remarkable improvements in terms of EE by using the proposed iterative resource allocation and power control scheme.