Zhengqiang Wang

Chongqing University of Posts and Telecommunications · School of Communication and Information Engineering

In price-based cognitive radio networks, the Primary user (PU) can allow the Secondary users (SUs) to access by pricing if their interference power is under the Interference power constraint (IPC). The interaction between the PU and the SUs is modeled as a Stack-elberg game with the consideration of the Quality of service (QoS) of the SUs. The reve...

Real-time matting is a challenging research in deep learning. Conventional CNN (Convolutional Neural Networks) approaches are easy to misjudge the foreground and background semantic and have blurry matting edges, which result from CNN's limited concentration on global context due to receptive field. We propose a real-time matting approach called RM...

We investigate a mobile edge computing (MEC) system that supports collaborative task offloading, allowing busy users to offload their tasks to the server and idle users, or perform them locally. However, executing computing tasks consumes device energy, making idle users unwilling to perform other users' tasks due to limited battery capacity. Addit...

为了提高反向散射通信网络频谱效率、传输鲁棒性及信息安全性，该文提出一种基于硬件损伤的认知反向散射通信网络鲁棒安全资源分配算法。首先，考虑认知反向散射用户的最小安全速率、传输时间、能量收集和反射系数等约束，基于有界信道不确定性和频谱感知误差模型，建立一个多变量耦合的吞吐量最大化非凸资源分配问题。其次，利用最坏准则、连续凸近似和交替优化方法，将原问题转换为凸优化问题，并提出一种基于迭代的鲁棒资源分配算法。仿真结果表明，与现有算法对比，所提算法具有较好的鲁棒性。

Thanks to the development of the 6th generation mobile network that makes it possible for us to move towards an intelligent ubiquitous information society, among which some novel technologies represented by cell-free network has also attracted widespread academic attention. Cell-free network has brought distinguished gains to the network capacity w...

In the unmanned aerial vehicle (UAV) assisted non-orthogonal multiple access (NOMA) networks, the practical hardware impairments (HIs) and resource allocation is still a challenging problem. Most existing research on resource allocation algorithms for UAV communication is considered with the ideal hardware condition. However, the impact of HIs on s...

无人机(UAV)、非正交多址(NOMA)和反向散射通信(BC)相结合，可以满足热点地区高容量需求，提高通信质量。该文提出一种无人机辅助的NOMA反向散射通信系统最小速率最大化资源分配算法。考虑无人机发射功率、能量收集、反射系数、传输速率以及连续干扰消除(SIC)解码顺序约束，建立基于系统最小速率最大化的资源分配模型。首先利用块坐标下降将原问题分解为无人机发射功率优化、反射系数优化和无人机位置与SIC解码顺序联合优化3个子问题，然后使用反证法给出无人机最优发射功率，再用变量替换法和连续凸逼近将剩余子问题进一步转化为凸优化问题进行求解。仿真结果表明，所提算法在系统和速率与用户公平性之间具有较好折中。

In this paper, we investigate the sum rate (SR) maximization problem for downlink cooperative non-orthogonal multiple access (C-NOMA) system under in-phase and quadrature-phase (IQ) imbalance at the base station (BS) and destination. The BS communicates with users by a half-duplex amplified-and-forward (HD-AF) relay under imperfect IQ imbalance. Th...

In this paper, we investigate the Access Point (AP) selection problem in Cell-Free Massive multiple-input multiple-output (MIMO) system. Firstly, we add a connecting coefficient to the uplink data transmission model. Then, the problem of AP selection is formulated as a discrete combinatorial optimization problem which can be dealt with by the parti...

该文研究了智能反射面(IRS)辅助基于非正交多址接入(NOMA)技术的无人机(UAV)网络中的安全传输。为了使系统安全速率最大化，该文提出联合优化无人机位置、串行干扰消除解码顺序、IRS反射矩阵和UAV发射功率的资源优化问题。由于优化问题是一个混合整数非凸优化问题，该文提出一种基于块坐标下降的迭代算法，将原问题分解为3个子问题，采用基于惩罚、半正定松弛和连续凸逼近的方法求解子问题。仿真表明，所提算法的系统安全速率优于没有IRS辅助的NOMA方案和没有IRS辅助的正交多址方案。

Energy-efficient resource allocation for multi-cell multi-carrier non-orthogonal multiple access (MCMC-NOMA) is a challenging task due to the interference and other related factors, which makes obtaining an applicable solution in the real-time is even more challenging. In this paper, we aim to design a model capable of efficient resource allocation...

In this letter, a path dynamics assessment asynchronous advantage actor-critic scheduling algorithm (PDAA3C) is proposed to solve the MPTCP scheduling problem by using deep reinforcement learning Actor-Critic framework. The algorithm picks out the optimal transmitting path faster by multi-core asynchronous updating and also guarantee the network fa...

As a promising new technology for green communication, backscatter communication has attracted wide attention in academics and industry. This paper studies the resource allocation problem for an unmanned aerial vehicle (UAV)-assisted backscatter communication network. The UAV acts as an airborne mobile base station and broadcasts signals to the gro...

Driven by massive connections and exponential growth of data in mobile devices, Non-orthogonal multiple access (NOMA) has become a candidate access technology to meet the requirement of Internet of things (IoT) in the future network. The combination of multi-carrier technology and cooperative communication is an efficient solution to significantly...

Energy-efficient resource allocation for multi-cell multi-carrier non-orthogonal multiple access (MCMC-NOMA) is a challenging task due to the interference and other related factors, which makes obtaining an applicable solution in the real-time is even more challenging. In this paper, we aim to design a model capable of efficient resource allocation...

In Non-Orthogonal Multiple Access (NOMA), the best way to fully exploit the benefits of the system is the efficient resource allocation. For the NOMA power domain, the allocation of power and spectrum require solving the mixed-integer nonlinear programming NP-hard problem. In this paper, we investigate user scheduling and power allocation in Multi-...

As a promising new technology for green communication, backscatter communication has attracted wide attention in academics and industry. This paper studies the resource allocation problem for an unmanned aerial vehicle (UAV)-assisted backscatter communication network. The UAV is used as an airborne mobile base station (BS) by time division multiple...

In this paper, we investigate energy-efficient resource allocation in relay-assisted backscatter communication systems. We employed a backscatter user device, and a relay device that supported to operate in different modes, i.e., the backscatter communication (BackCom) mode and the harvest-then transmit (HTT) mode, respectively. We formulate the sy...

This paper investigates the sum rate (SR) maximization problem for downlink cooperative non-orthogonal multiple access (C-NOMA) systems with hardware impairments (HIs). The source node communicates with users via a half-duplex amplified-and-forward (HD-AF) relay with HIs. First, we derive the SR expression of the systems under HIs. Then, SR maximiz...

Wireless-powered communication and reconfigurable intelligent surface (RIS) can complement each other for increasing energy utilization and spectrum efficiency by reconfiguring the surrounding radio environment, however, which has not been sufficiently studied by the existing works. In this paper, we propose a joint radio resource and passive beamf...

This paper considers an unmanned aerial vehicle (UAV)-enabled wireless power transfer (WPT) system, in which a UAV hovers in a given flying altitude to transfer energy to more than two energy receivers (ERs) on the ground. We consider to maximize the sum energy and weighted sum energy of ERs by UAV placement optimization. As the sum energy and weig...

The unmanned aerial vehicle (UAV) based aerial base station (BS) has emerged as a feasible solution to the high traffic demands of the future wireless networks. It is essential that UAV can integrat with non-orthogonal multiple access (NOMA) to support the massive connection service. In this paper, we study the problem of weighted sum rate maximiza...

In this paper, we investigate the subcarriers combination selection and the subcarriers activation of OFDM-IM system. Firstly, we propose an algorithm to solve the problem of subcarriers combination selection based on the transmission rate and diversity gain. Secondly, we ropose a more concise algorithm to solve the problem of power allocation and...

In this paper, we investigate energy efficiency (EE) maximization in multicell multicarrier non-orthogonal multiple access (MCMC-NOMA) networks with hardware impairments (HIs). We formulate the optimization problem as a mixed integer nonlinear NP-hard problem, which is difficult to solve efficiently. To solve this problem, we decompose it into two...

As energy efficiency (EE) is a key performance indicator for the future wireless network, it has become a significant research field in communication networks. In this paper, we consider multi-cell multi-carrier non-orthogonal multiple access (MCMC-NOMA) networks and investigate the EE maximization problem. As the EE maximization is a mixed-integer...

User-centric ultra-dense network (UUDN) has become a promising paradigm with the advantages over traditional cell-centric structure with respect to spectrum and power usage. This paper introduces full duplex (FD) technology into UUDN and presents a joint scheme of user access, subchannel allocation and power control for FD UUDN. The scheme firstly...

This paper studies the price-based power control strategies for non-orthogonal multiple access (NOMA) based cognitive radio networks. The primary user (PU) profits from the secondary users (SUs) by pricing the interference power made by them. Then, SUs cooperate to maximize their total revenue at the base station (BS) with successive interference c...

In this paper, we consider the resource allocation problem to maximize the minimum (max–min) user’s secure energy efficiency (SEE) in downlink massive multiple-input multiple-output (MIMO) systems with simultaneous wireless information and power transfer (SWIPT). First, transmission power and power splitting ratio are designed to achieve the max–mi...

This paper investigates the resource allocation algorithm to maximize the minimum user's rate in wireless power transfer (WPT) enabled massive multiple input multiple output (MIMO) systems. In the proposed system, a power beacon (PB) with multiple antennas transmits energy to the sensor node (SN) by WPT, and the SN transmits all the received energy...

This paper investigates the energy efficient resource allocation algorithm to maximize the minimum user's energy efficiency (EE) in wireless power transfer (WPT) enabled massive multiple-input multiple-output (MIMO) systems with the harvest-then-transmit protocol. By adopting the quadratic transform method, the non-differential EE maximization prob...

In this paper, we investigate the energy efficiency (EE) maximization in multi-cell multi-carrier non-orthogonal multiple access (MCMC-NOMA) networks. To achieve this goal, an optimization problem is formulated then the solution is divided into two parts. First, we investigate the inter-cell interference mitigation and then we propose an auction-ba...

In this letter, we investigate the price-based power allocation for non-orthogonal multiple access (NOMA) networks, where the base station (BS) can admit the users to transmit by pricing their power. Stackelberg game is utilized to model the pricing and power purchasing strategies between the BS and the users. Based on backward induction, the prici...

To improve the secrecy performance of cellular-enabled unmanned aerial vehicle (UAV) communication networks, this paper proposes an aerial cooperative jamming scheme and studies its optimal design to achieve the maximum average secrecy rate. Specifically, a base station (BS) transmits confidential messages to a UAV and meanwhile another UAV perform...

With the increasing requirements of high data rates and large connectivity, the application of the non-orthogonal multiple access (NOMA) technique in heterogeneous networks (HetNets) has become an inevitable trend for 5G communication systems in order to achieve good spectrum efficiency and system throughput. Moreover, the energy-constrained low-po...

In this paper, we investigate a downlink outage-constrained robust resource allocation algorithm for robust transmission in power domain non-orthogonal multiple access based underlay cognitive radio networks. Our goal is to maximize the sum energy efficiency of secondary users (SUs) considering imperfect channel state information while protecting t...

This paper considers the price-based resource allocation problem for wireless power transfer (WPT)-enabled massive multiple-input multiple-output (MIMO) networks. The power beacon (PB) can transmit energy to the sensor nodes (SNs) by pricing their harvested energy. Then, the SNs transmit their data to the base station (BS) with large scale antennas...

In this paper, the interference-efficient based resource allocation for uplink transmission in an OFDMA-based cognitive radio network is studied. The interference efficiency (IE) is defined as the total data rate of secondary users (SUs) over sum interference power imposed on primary users (PUs). The objective is to maximize the total IE of SUs sub...

Price-based power control problem is investigated in the spectrum sharing cognitive radio networks (CRNs) by Stackelberg game. Using backward induction, the revenue function of the primary user (PU) is expressed as a non-convex function of the transmit power of the secondary users (SUs). To solve the non-convex problem of the PU, a branch and bound...

This paper investigates energy-efficient resource allocation problem for the wireless power transfer (WPT) enabled multi-user massive MIMO systems. In the considered systems, the sensor nodes (SNs) are firstly powered by WPT from the power beacon (PB) with a large scale of antennas. Then, the SNs use the harvested energy to transmit the data to the...

This paper investigates the energy efficiency (EE) optimization for massive multiple-input multiple-output (MIMO) systems powered by wireless power transfer (WPT) with hardware impairments at sensor nodes (SNs). In the considered system, the SNs are first powered by the WPT from power beacon (PB). Then, the SNs use the harvested energy to transmit...

In this letter, we study the resource allocation for the downlink cooperative non-orthogonal multiple access (NOMA) systems based on the amplifying-and-forward protocol relay transmission. A joint power allocation and amplification gain selection scheme are proposed. Fractional programming and the iterative algorithm based on the Lagrangian multipl...

A novel price-based power allocation algorithm is proposed based on the Stackelberg game for cellular downlink non-orthogonal multiple access (NOMA) networks. First, the closed-form solution is given for two users’ case, and shown that it is possible to allocate the transmit power to both users or only the user with the better channel condition. Th...

In this letter, we consider the power allocation scheme with rate proportional fairness to maximize energy efficiency in the downlink the non-orthogonal multiple access (NOMA) systems. The optimization problem of energy efficiency is a non-convex optimization problem, and the fractional programming is used to transform the original problem into a s...

Cellular network can use renewable energy through energy harvesting technology in green communication. In this paper, power allocation for heterogeneous cellular networks (HetNets) with energy harvesting is proposed to maximize the system energy efficiency. Considering the minimal transmit rate of the users and the battery capacity of the system, a...

Software defined networking is an emerging network paradigm which is considered to be the future evolution trend of network, the network efficiency is determined by the controller. A modeling approach is proposed to evaluate the throughput and time delay of the control plane based on queuing theory. The influence of the number of switches and threa...

In this letter, we investigate the price-based power allocation with rate proportional fairness constraint in downlink non-orthogonal multiple access (NOMA) systems. The Stackelberg game is utilized to model the interaction between the base station (BS) and users. The revenue maximization problem of the BS is first converted to rate allocation prob...

This letter studies the price-based power control algorithm for the spectrum sharing cognitive radio networks. The primary user (PU) profits from the secondary users (SUs) by pricing the interference power made by them. The SUs cooperate with each other to maximize their sum revenue with the signal-to-interference plus noise ratio (SINR) balancing...

This paper considers a price-based power control problem in the cognitive radio networks (CRNs). The primary user (PU) can admit secondary users (SUs) to access if their interference powers are all under the interference power constraint. In order to access the spectrum, the SUs need to pay for their interference power. The PU first decides the pri...

This paper investigates the price-based power control problem in the spectrum sharing cognitive radio networks. The primary user (PU) can admit secondary users (SUs) to access by pricing their interference power under the interference power constraint. We model the interaction between the PU and the SUs as a Stackelberg game. The revenue function o...

Spectrum sharing problem in multi-channel cognitive radio networks was modeled as a cooperative game. A utility function based on the product of the signal to interference plus noise ratio (SINR) was proposed. The power allocation of secondary users was determined by maximizing the product of the utility function to ensure that the interference pow...

This letter investigates price-based power control for cognitive radio networks (CRNs) with interference cancellation. The base station (BS) of the primary users (PUs) will admit secondary users (SUs) to access by pricing their interference power under the interference power constraint (IPC). We give the optimal price for BS to maximize its revenue...

This letter investigates price-based power control problem in the spectrum sharing cognitive radio networks (CRNs). The base station (BS) of primary users (PUs) can admit secondary users (SUs) to access if their interference power is under the interference power constraint (IPC). In order to access the spectrum, the SUs need to pay for their interf...

In the spectrum underlay model, cognitive radios can access the spectrum owned by primary users if they can limit their interference power below a certain threshold, called interference temperature limit (ITL). In this paper, we study the power control problem under ITL. By considering both efficiency and fairness, the power control problem is mode...