Adaptive Power Control Scheme Research Articles

ATOMIC: Adaptive Transmission Power and Message Interval Control for C-V2X Mode 4

To support the emerging vehicle-to-everything (V2X) communication for autonomous vehicles and smart transportation services, 3rd Generation Partnership Project (3GPP) has recently introduced cellular V2X (C-V2X) standards. In C-V2X, radio resources can be managed not only centrally by the cellular network base station, but also in a completely distributed manner ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Mode 4</i> ) without any cellular support. However, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Mode 4</i> may suffer significant collisions and interference in a dense environment since each vehicle selects its own resources to transmit V2X messages autonomously without adapting appropriately to vehicle density. To address this challenge, we propose <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ATOMIC</i> , an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Adaptive Transmission pOwer and Message Interval Control scheme for C-V2X Mode 4</i> , in which each vehicle utilizes real-time channel sensing and neighbor information to reduce channel contention for improved reliability and latency. Through analysis and extensive simulations, we show that <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ATOMIC</i> outperforms the standard <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Mode 4</i> in both urban and highway scenarios especially in highly dense environments.

Joint optimization of power control and time slot allocation for wireless body area networks via deep reinforcement learning

E-healthcare system based on wireless body area network (WBAN) promises to produce potential benefits in health-care industry. A major issue of such an on-body networked system is the energy efficiency, that is, how to improve the reliability and effectiveness of physiological data transmission with the energy constraints of tiny wireless sensors. Motivated by this, we consider an individual WBAN scenario, focusing on finding an adaptive time slot allocation and power control scheme to maximize the average energy efficiency for implementing the task of health monitoring. We formulate the maximization problem with latency and sensors’ energy budget constraints as a markov decision process (MDP). As a solution, we propose a deep reinforcement learning-based scheme to make a sequence decision for the MDP, which jointly optimizes power control and slot allocation. Simulation results show that the proposed scheme is energy efficient and has a good convergence.

Adaptive Secure MIMO Transmission Mechanism against Smart Attacker

The MIMO transmission against a smart attacker has recently been formulated as a noncollaborative game, in which both the MIMO transmitter and the malicious attacker try to maximize their predefined utilities. In this paper, by carefully analyzing the Nash Equilibrium (NE), we focus on the conditions, in which the gaming results incline to the malicious attacker instead of the MIMO transmitter. In this adverse case, it is highly desirable to develop an effective mechanism to suppress the attack intention by the attacker for better secure communication. Motivated by this, an adaptive secure MIMO transmission scheme was proposed to make the MIMO transmitter better resist malicious attackers in adverse channel conditions. Compared with the existing gaming-based strategy, not only the transmit power of the MIMO transmitter but also the transmission probability will be adjusted in the proposed adaptive secure transmission scheme. Our analysis results show that the proposed scheme can be regarded as a generalized adaptive transmission one, i.e., when the adaptive transmit power policy is enough to suppress the attack motivation, the proposed scheme will be reduced to the adaptive power control scheme; otherwise, both the adaptive transmit power and the adaptive probabilistic transmission can be employed to suppress the attack motivation. The analysis results confirm us that the proposed adaptive transmission scheme provides us a choice to enhance the secure MIMO transmission performance in adverse conditions.

Event-Based Adaptive Power Control in Vehicular Networked Systems With State-Dependent Bursty Fading Channels

This brief considers both safety and efficiency issues for vehicular networked systems (VNSs) where vehicles exchange information over vehicle to vehicle (V2V) wireless communication channels. One of the challenges to ensure system safety and efficiency lies in unreliable V2V fading channel conditions, which stochastically change as a function of the vehicle states and are subject to severe data rate drops. By adopting a bursty state-dependent fading model, this brief presents a novel event-based adaptive power control scheme. Under this scheme, the VNS assures efficient use of communication resources while preserving almost sure asymptotic stability. The benefits of the proposed scheme over other power policies are shown in a leader-follower formation control example.

Node-Position-Based Joint Relay Selection and Adaptive Power Control Scheme in Wireless Body Area Networks

Sport and healthcare monitoring have become more and more popular in our everyday life, benefiting from the deploying of Wireless Body Area Networks. In these cases, data transmission reliability should be studied to receive the accurate real-time feedbacks, which contain rich biomedical information, such as heartbeat, and breathing process. However, wireless on-body channels experience significant temporal variation due to body movements and single-hop communication scheme cannot adapt to highly dynamic network topology. In this paper, a joint relay selection and power control scheme (JRP) is proposed to improve transmission reliability. We take running activity for experimental study, the influence of nodes’ positions to radio performance is evaluated. By analyzing the source and destination, JRP can decide the way to finish this communication by either relay selection or power control. In addition, the acceleration of each node is measured by accelerometers. Thus, with the help of real-time received signal strength indication and acceleration, JRP can pick several potential relay nodes for the source node’s transmission request. Finally, the experimental result shows that our scheme can achieve a good tradeoff between reliability and energy consumption.

QoS-based adaptive power control scheme for co-located WBANs: a cooperative bargaining game theoretic perspective

This paper proposes a new Quality of Service (QoS)-based adaptive power control (QPC) scheme for interference mitigation among co-located wireless body area networks (WBANs). The problem can be formulated as a Nash bargaining game. The proposed solution not only achieves the Pareto optimal solution, but also guarantees the fairness among competing players. Owing to the special features of WBANs, the proposed utility function considers the urgency of the sensed data and the energy efficiency of sensors, which are indicated by emergency index and energy consumption factor, respectively. Thus, the transmission power is adjusted dynamically to adapt to the different QoS requirements under the constraints of permissible maximum transmission power and desired minimum signal-to-interference-plus-noise-ratio (SINR). Moreover, a unified analytical framework based on Lagrange multiplier approach is adopted to optimize the Nash product, where near optimal power control strategy is derived iteratively using the fix-point method. Extensive simulation results show that compared with the existing benchmark algorithms, the proposed QPC scheme has better performance in terms of energy efficiency, network reliability, Pareto optimality and fairness.

An Overlapping Coalitional Game for Cooperative Spectrum Sensing and Access in Cognitive Radio Networks

Cognitive radio networks (CRNs) provide an effective solution to address the increasing demand for spectrum resources. The cooperation among secondary users (SUs) improves the sensing performance and spectrum efficiency. In this paper, we study the traffic-demand-based cooperation strategy of SUs in multichannel CRNs, in which each SU makes its own cooperative sensing decision according to its traffic demand. When an SU has high traffic demand, it can choose to sense multiple channels in the sensing period and obtain more chances to use spectrum resources. If an SU has no data to transmit, it can choose not to perform spectrum sensing. We formulate this problem as a nontransferable utility (NTU) overlapping coalitional game. In this game, each SU implements a cooperation strategy according to its expected payoff, which takes into account the expected throughput and energy efficiency. We propose two different algorithms, namely, an overlapping coalition formation (OCF) algorithm and a sequential coalition formation (SCF) algorithm, to obtain a coalition structure. The OCF algorithm guarantees that the coalition structure is stable, whereas the SCF algorithm has lower computational complexity and less information exchange among SUs. Moreover, when being assigned a certain channel, SU implements an adaptive transmission power control scheme to further improve its energy efficiency. Simulation results show that our proposed algorithms achieve a higher aggregate throughput than the disjoint coalition formation algorithm from the literature, where each SU can join only one coalition.

Cognitive hierarchy thinking based behavioral game model for IoT power control algorithm

The Internet of Things (IoT) describes a future world of interconnected physical objects, with several applications in the areas of smart environments. To implement the IoT concept, the research in the areas of power controlled circuits, embedded systems design, network protocols and control theory should be required. With the much advancement in these areas, the realization of IoT is becoming increasingly probable. In this paper, we propose a novel adaptive power control scheme for IoT systems. Based on the cognitive hierarchy thinking mechanism, our proposed scheme is designed as a new behavioral game model to adaptively control the power level. To effectively solve the power control problem in IoT systems, game theory is well-suited and an effective tool. The experimental result illustrates that our game-based approach can get an effective transmission power, which can make the communication rate maximal. Under dynamic IoT system environments, it is highly desirable property.

An Adaptive Power Control Scheme for Multicast Service in Green Cellular Railway Communication Network

Along with emerging increasing multimedia service need from the big amount of users in the train, wireless cellular railway network has big energy saving potential with its own specific characteristics, which is widely deployed over the world. Enhanced Multimedia Broadcast Multicast Service (E-MBMS) is a prevalent solution for high speed data handling. In this paper, to achieve an energy efficient solution for wireless cellular railway network, we proposed an optimal power control solution to adjust eNodeB's transmission power adaptively based on actual Signal to Interference plus Noise Ratio (SINR) for Multimedia Broadcast multicast service Single Frequency Network (MBSFN) at User Equipment (UE) side when provide E-MBMS. We established the system model and proposed the optimization algorithms to calculate the E-MBMS transmit power. We also designed the geometry group scheme to significantly reduce the calculation effort. And proposed the Mobility offset parameter to cope with high speed mobility of the train and variation of signal level. Finally, Simulation results showed that this solution can be a good way for high network energy efficiency and can dynamically adjust the output power for the multicast service in the wireless cellular railway communication network.

Adaptive power control for mutual interference avoidance in industrial internet-of-things

With the vigorous development of the Internet of Things and 5G technology, such as machine-to-machine and device-todevice, all kinds of data transmission including environmental monitoring and equipment control strengthens the key role of wireless sensor networks in the large-scale wireless communication system. However, especially in the complex industrial wireless applications, the low utilization efficiency of the limited wireless radio resource enhances the coexistence problem between heterogeneous networks. In this paper, from the severe mutual interference point of view, a mathematical model regarding cumulative interferences in the industrial wireless sensor networks is described. Then, from the perspective of mutual interference avoidance, an adaptive power control scheme is proposed in order to handle the normal communication needs on both the primary link and the secondary link. At last, nonlinear programming is taken to solve the corresponding optimization problem. Some typical analyses are given to verify the effectiveness of the proposed scheme on optimizing the tradeoff between the system throughput and energy consumption. Especially, the energy-efficiency of the novel scheme for Industrial Internet of Things is also analysed. Results show that the proposed power control is efficient. The throughput could be enhanced and the energy consumption could be reduced with the guarantee of mutual interference avoidance.

Power Control in Wireless Sensor Networks with Variable Interference

Adaptive transmission power control schemes have been introduced in wireless sensor networks to adjust energy consumption under different network conditions. This is a crucial goal, given the constraints under which sensor communications operate. Power reduction may however have counterproductive effects to network performance. Yet, indiscriminate power boosting may detrimentally affect interference. We are interested in understanding the conditions under which coordinated power reduction may lead to better spectrum efficiency and interference mitigation and, thus, have beneficial effects on network performance. Through simulations, we analyze the performance of sensor nodes in an environment with variable interference. Then we study the relation between transmission power and communication efficiency, particularly in the context of Adaptive and Robust Topology (ART) control, showing how appropriate power reduction can benefit both energy and spectrum efficiency. We also identify critical limitations in ART, discussing the potential of more cooperative power control approaches.

Underlay cognitive relay networks with imperfect channel state information and multiple primary receivers

In this study, the authors investigate the effect of imperfect channel state information (CSI) on underlay cognitive radio networks in the presence of multiple primary users (PUs). Particularly, with multiple proactive partial decode-and-forward (DF) relays available, both the relay selection channels and interference channels are assumed to be imperfect. In this context, firstly, based on the instantaneous CSI (ICSI) of interference channels, exact closed form expressions for the outage probability (OP) and the interference probability (IP) are derived, where IP is used as a performance metric to quantify the impact of harmful interference caused by secondary user (SU) on PUs. It is shown that, when the ICSI of interference channels are imperfect, the secondary networks always interfere with PUs' communications. Then, to reduce the harmful interference caused by secondary nodes, we propose an adaptive power control scheme relying on the partial CSI (PCSI) of interference channels. Finally, simulation results verify the accuracy and effectiveness of the author's analytical study, and indicate the proposed scheme strikes a good tradeoff between the interference introduced by secondary nodes on PUs and SU's performance.

Clustering Based Adaptive Power Control for Interference Mitigation in Two-Tier Femtocell Networks

Two-tier femtocell networks, consisting of a conventional cellular network underlaid with femtocell hotspots, play an important role in the indoor coverage and capacity of cellular networks. However, the cross- and co-tier interference will cause an unacceptable quality of service (QoS) for users with universal frequency reuse. In this paper, we propose a novel downlink interference mitigation strategy for spectrum-shared two-tier femtocell networks. The proposed solution is composed of three parts. The first is femtocells clustering, which maximizes the distance between femtocells using the same slot resource to mitigate co-tier interference. The second is to assign macrocell users (MUEs) to clusters by max-min criterion, by which each MUE can avoid using the same resource as the nearest femtocell. The third is a novel adaptive power control scheme with femtocells downlink transmit power adjusted adaptively based on the signal to interference plus noise ratio (SINR) level of neighboring users. Simulation results show that the proposed scheme can effectively increase the successful transmission ratio and ergodic capacity of femtocells, while guaranteeing QoS of the macrocell.

Efficacy of coverage radius‐based power control scheme for interference mitigation in femtocells

A novel coverage radius-based downlink power control scheme to mitigate interference in densely deployed femtocells is presented. A femtocell access point (FAP) self-update algorithm is implemented, which determines the coverage radius of the femtocell with respect to its farthest served femtocell user equipment (FUE). Based on varying coverage radii, a max/min function is used to adjust the downlink transmit power value of a FAP. System-level simulations are performed to compare the performance of the presented scheme with the existing fixed coverage radius schemes. Even though the proposed scheme results in better cross-tier signal to interference plus noise ratio (SINR) values, due to a low co-tier SINR it is found that the efficacy of adaptive power control schemes based on the pilot power of a FAP is less significant if FUEs are located close to the neighbouring FAPs in densely deployed urban femtocells.

Femtocell network power control scheme based on the weighted voting game

Future wireless networks are designed to cope with drastically increasing user demands. However, network resources reach the limits of their capacity to user requirements. Recently, femtocell networks have attracted much attention to enhance the efficiency of wireless resource usage. In this article, a new adaptive power control scheme is developed for the femtocell network system. By using the concept of the weighted voting game, the proposed scheme adaptively adjusts a transmit power level while ensuring relevant tradeoff between system efficiency and fairness. This power control paradigm can provide the ability to practically respond to current communication conditions and suitable for real network operations. Simulation results are presented to verify the effectiveness of the proposed voting game-based scheme in comparison with the existing schemes.

Acceptable intersystem interference probability distribution between adjacent terrestrial and satellite networks operating above 10 GHz

The present paper studies, interference issues arising from, the spectral and spatial coexistence between terrestrial stations participating in fixed wireless networks or in a point-to-point link and satellite terminals belonging to a satellite communication network, operating at frequencies above 10 GHz. Rain attenuation is considered to be the dominant fading mechanism at this frequency range. The acceptable intersystem interference probability AIIP of the carrier-to-interference ratio CIR of a terrestrial station interfered by a satellite is defined and analytically calculated. Adaptive power control schemes are assumed to operate for both networks. The correlated propagation fading phenomena over multiple terrestrial and slant paths are accurately incorporated. The proposed model is physical and can be applied on a global scale since incorporates properly the local climatic conditions concerning the point rainfall rate and the spatial rainfall inhomogeneity. Useful numerical results of the present model are finally provided and the impact of various crucial operational and geometrical parameters of satellite and fixed wireless networks' coexistence is also examined.

펨토셀 환경에서 채널별 전송전력의 적응적 제어 기법

본 논문은 펨토셀 환경에서 시스템 용량 향상 및 호손율 감소를 위해 펨토 기지국이 자기 최적화 기법을 이용하여 채널별 전송전력을 적응적으로 제어하는 방법을 제안한다. 펨토셀 관련 국제표준에서는 요구사항으로 펨토셀 밀집 배치에 따라 성능 열화가 없어야 한다는 점을 들고 있다. 제안방식에서는 각 펨토 기지국이 펨토 게이트웨이를 통해 전달받은 이웃 기지국의 채널별 전송전력 정보와 주기적 스펙트럼 감지를 통해 측정한 이웃 펨토셀로부터의 채널별 수신 전력을 바탕으로 자신의 채널별 전송전력을 결정하게 된다. 또한 각 채널별로 펨토 사용자 단말(Femto Mobile Station: FMS)의 이동에 따라 적응적으로 전송전력을 제어함으로써, 핸드오버 감소 및 펨토셀 간 균등한 서비스 기회를 가지도록 한다. 이를 통해 펨토셀 밀집 배치에 따른 성능 열화를 방지할 뿐만 아니라, 펨토셀이 밀집할수록 시스템 용량이 향상되고 호손율이 낮아지는 효과를 얻을 수 있다. 또한 채널별 전송전력을 독립적으로 제어함으로써 커버리지 홀을 줄일 수 있으며, 시스템 내에 존재하는 펨토셀의 개수와 상관없이 항상 일정 수준 이상의 커버리지와 호손율을 유지할 수 있다. 컴퓨터 모의실험을 통해 시스템 용량과 호손율 측면에서 기존 방식과 비교 분석하였으며 그 결과 제안한 방식이 기존 방식보다 우수함을 볼 수 있었다. In this paper, we propose an adaptive power control scheme employing a self-optimization concept in femtocell systems, in order to improve system capacity, thereby reducing call-drop probability. In the proposed scheme, each femto base station(FBS) controls individual channel's transmission power base on two parameters; the neighboring cell's transmission power for each individual channel which is delivered from a femto-gateway and the received power strength from neighboring cells which is periodically measured by means of a spectrum sensing. Adaptive adjustment of individual channel's transmission power in accordance with femto mobile station(FMS) mobility features can also reduce undesirable handovers and evenly distribute traffic load over all femtocells. In addition, the manipulative control of channel's transmission power is able to keep the system coverage and the call-drop probability within an acceptable range, regardless of density of femtocells. Computer simulation shows that the proposed scheme outperforms existing schemes in terms of the system coverage and the call-drop probability.

Wireless Network Coding Diversity Technique Based on Hybrid AF/DF Relay Method Employing Adaptive Power Control at Relay Node for Bidirectional Two-Hop Wireless Networks

In this paper, we propose a wireless network coding diversity technique based on hybrid amplify-and-forward/decode-and-forward relay method employing adaptive power control for two-hop wireless networks in order to improve relay node position flexibility. Wireless network coding diversity based on hybrid relay method selects either modulation symbol level wireless network coding diversity or bit sequence level wireless network coding diversity as its wireless network coding diversity scheme according to the cyclic redundancy check result at the relay node. Moreover, the adaptive power control scheme proposed here controls the relay node's transmit power according to its position. Computer simulations verify that wireless network coding diversity based on hybrid relay method employing the adaptive power control scheme can expand the area wherein the relay node can be located while satisfying the required communication quality by 4.56 times compared to the conventional wireless network coding diversity scheme. Therefore, we confirm that our proposed scheme can increase relay node position flexibility.

Adaptive online power control scheme based on the evolutionary game theory

In view of the remarkable growth in the number of users and the limited network resource, an efficient network management is very important and has been an active area of research over the years. Especially, during wireless network operations, adaptive power control is an effective way to enhance the network performance. In this study, a new online power control scheme is proposed based on the evolutionary game theory. To converge a desirable network equilibrium, the proposed scheme adaptively adjusts a transmit power level in a distributed online manner. For the efficient network management, the online approach is dynamic and flexible that can adaptively respond to current network conditions. With a simulation study, the author demonstrates that the proposed scheme improves the network performance under widely diverse network environments.

Performance Analysis of Joint Diversity Combining, Adaptive Modulation, and Power Control Schemes

Adaptive modulation and diversity combining represent very important adaptive solutions for future generations of wireless communication systems. Indeed, in order to improve the performance and the efficiency of these systems, these two techniques have been recently used jointly in new schemes named joint adaptive modulation and diversity combining (JAMDC) schemes. Considering the problem of finding low hardware complexity, bandwidth-efficient, and processing-power efficient transmission schemes for a downlink scenario and capitalizing on some of these recently proposed JAMDC schemes, we propose and analyze in this paper three joint adaptive modulation, diversity combining, and power control (JAMDCPC) schemes where a constant-power variable-rate adaptive modulation technique is used with an adaptive diversity combining scheme and a common power control process. More specifically, the modulation constellation size, the number of combined diversity paths, and the needed power level are jointly determined to achieve the highest spectral efficiency with the lowest possible processing power consumption quantified in terms of the average number of combined paths, given the fading channel conditions and the required bit error rate (BER) performance. In this paper, the performance of these three JAMDCPC schemes is analyzed in terms of their spectral efficiency, processing power consumption, and error-rate performance. Selected numerical examples show that these schemes considerably increase the spectral efficiency of the existing JAMDC schemes with a slight increase in the average number of combined paths for the low signal-to-noise ratio range while maintaining compliance with the BER performance and a low radiated power which yields to a substantial decrease in interference to co-existing users and systems.