Hualiang Chen

Throughput and energy efficiency of a novel cooperative ARQ strategy for wireless sensor networks

As energy constrained networks, wireless sensor networks (WSNs) are composed of sensor nodes typically powered by batteries, for which replacement or recharging for these batteries is very difficult. So it is important to make the best use of the batteries to prolong the lifetime of the networks. With this objective in mind, a cooperative automatic retransmission request (CARQ) protocol is introduced for WSNs and a generalized discrete time Markov chain (DTMC) model is proposed for analyzing the throughput and energy efficiency of the protocol. Numerical results show that the energy efficiency of the scheme is much better than that of the traditional ARQ scheme.

A distributed resource management scheme for D2D communications based on coalition formation game

D2D (device-to-device) communications utilize the proximity between wireless users in the same cell, make the equipments directly communicate with each other, and dramatically improve the network performance. However, it also induces some urgent problems such as severe interference between the devices who share channels. In this paper, the resource management is investigated. Specifically, we model the joint mode selection and spectrum sharing problem as a coalition formation game. A distributed coalition formation algorithm is proposed, which aims at improving the sum achievable rate of the D2D communication system. Numerical results validate our algorithm, and show the proposed scheme can effectively improve the system performance.

Stackelberg Game Based Power Allocation for Physical Layer Security of Device-to-device Communication Underlaying Cellular Networks

Abstract The problem of power allocation for device-to-device (D2D) underlay communication to improve physical layer security is addressed. Specifically, to improve the secure communication of the cellular users, we introduce a Stackelberg game for allocating the power of the D2D link under a total power constraint and a rate constraint at the D2D pair. In the introduced Stackelberg game the D2D pair works as a seller and the cellular UEs work as buyers. Firstly, because the interference signals from D2D pair are unknown to both the legitimate receiver and the illegitimate eavesdropper, it is possible that a cellular UE decline to participate in the introduced Stackelberg game. So the condition under which a legitimate user will participate in the introduced Stackelberg game is discussed. Then, based on the Stackelberg game, we propose a semi-distributed power allocation algorithm, which is proved to conclude after finite-time iterations. In the end, some simulations are presented to verify the performance improvement in the physical layer security of cellular UEs using the proposed power allocation algorithm. We can determine that with the proposed algorithm, while the D2D pairs communication demand is met, the physical layer security of cellular UEs can be improved.

Joint Spectrum and Power Allocation for Green D2D Communication with Physical Layer Security Consideration

In this paper, we consider cooperative D2D communications in cellular networks. More precisely, a cellular user leases part of its spectrum to facilitate the D2D communication with a goal of improving the energy efficiency of a D2D pair. However the D2D pair is untrusted to the cellular user, such resource sharing may result in the information of this cellular user unsecured. In order to motivate the cellular user’s generosity, this D2D pair needs to help the cellular user maintain a target secrecy rate. To address this issue, we formulate a joint spectrum and power allocation problem to maximize the energy efficiency of the D2D communication while guaranteeing the physical layer security of the cellular user. Then, a theorem is proved to indicate the best resource allocation strategy, and accordingly, an algorithm is proposed to find the best solution to this resource allocation problem. Numerical results are finally presented to verify the validity and effectiveness of the proposed algorithm.

Effect of outdated CSI on buffer-aided underlay cognitive relay networks

This work studies the impact of outdated channel state information (CSI) on decode-and-forward (DF) buffer-aided underlay cognitive relay networks (CRNs), with the following three key constraints considered: the maximum transmit power of the secondary network (P), the peak interference power at the primary user (I) and the interference power at the secondary network caused by the primary network (PPS). This makes it much more involved to handle with than existing works. By modeling the transitions of the buffer states with Markov chain theory, a closed-form expression of the outage probability for the system with finite-size buffers is derived, which depicts the impact of outdated CSI on the outage performance of buffer-aided CRNs. In addition, it is also demonstrated that the performance of the secondary network is improved with the increase of the interference threshold that the primary users can tolerate, but decreases with the increase of the transmit power of the primary network, which is useful in the design of buffer-aided CRNs. Monte-Carlo simulations are given to verify the validity of the theoretical analysis.

Coalition formation based energy efficient spectrum leasing in doubtful inband cooperative D2D communications

In this paper, we investigate an inband cooperative device-to-device (D2D) communication system in cellular networks. Cellular users and D2D pairs help each other to improve their respective performance. Specifically, via coalition formation, cellular users release some of their spectrum to D2D pairs so as to start the communications of the D2D pairs; at the same time, D2D pairs help to relay the messages of the cellular users. The D2D pairs are thought to be socially untrusted to the cellular users, as thus, a secrecy problem for cellular users comes into being due to the relaying. Then we address this problem from a physical layer security perspective. A coalition formation algorithm is designed to solve the spectrum management problem in this cooperative system. Numerical results show the validity of the proposed scheme.

A novel Markov-chain-based method for throughput analysis in truncated cooperative HARQ systems

Cooperative hybrid automatic retransmission request (HARQ) scheme, which combines cooperative communication (CC) technique and HARQ scheme, is one of the key techniques in the future wireless communications. It can reduce the retransmissions of traditional ARQ schemes, resulting in a better throughput performance. In this paper, we analyze the throughput performance of a truncated cooperative HARQ scheme with decode-and-forward (DF) relaying. A discrete time Markov chain (DTMC) model is introduced, and a closed-form expression of the throughput of the truncated cooperative HARQ scheme is derived based on the outage behavior of the scheme. Numerical and simulation results are presented to validate our analysis.

Performance Analysis of Cooperative ARQ Scheme with Co-channel Interference

Abstract In this paper, the performance of cooperative decode-and-forward (DF) automatic-repeat-request (ARQ) scheme with co-channel interference is investigated in a long-term static Rayleigh fading environment. We assume that the relay node is impaired by M interferers and the destination node is impaired by N interferers. A closed-form expression for the outage probability of cooperative DF ARQ scheme with co-channel interference is derived. Then we analyze the average throughput of the scheme with co-channel interference and further derive that the average throughput is mainly influenced by the interferers at the destination node. The average total power consumption per information packet of cooperative DF ARQ scheme with co-channel interference is investigated and a closed-form expression is obtained for cooperative DF ARQ scheme with co-channel interference, in which the source and relay may use different transmission power level in different transmission time slots. The closed-form expression is valid for any maximum number of transmission time slots L allowed by the protocol and may play a key role in optimizing power allocation. Numerical and simulation results are presented to verify our analysis.

Outage probability of cooperative decode-and-forward ARQ scheme with co-channel interference

In this paper we analyze the effect of co-channel interference on the performance of cooperative decode-and-forward (DF) automatic-repeat-request (ARQ) scheme under Rayleigh fading channels. We assume that the relay node is affected by one interferer and the destination node is affected by another one. The outage probability of the cooperative DF ARQ scheme is derived based on the maximal ratio combining (MRC) technique. The closed-form expression clearly shows the outage probability has much to do with the maximum number of ARQ transmissions. Finally, Monte Carlo simulation results verify our theoretical analysis.

Cooperative ARQ in wireless sensor networks: Outage behavior and throughput efficiency

In this paper, we investigate the outage behavior and throughput efficiency of a three-node cooperative ARQ system, which is equipped with a decode-and-forward relay node. We introduce four different cooperative ARQ protocols, followed by the analysis of their outage behavior and throughput efficiency under two different kinds of channel dynamics. We propose a general discrete time Markov chain model to calculate the throughput efficiencies for all the four protocols. Simulation results show the validity of our demonstration. And our analysis gives some guidance for the application of these protocols in wireless sensor networks.