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MONET. 01/2012; 17:45-52.
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ABSTRACT: As a new multimedia information acquisition and processing method, wireless multimedia sensor network (WMSN) has great application potential and attracts more and more attentions. Compared to traditional wireless sensor networks, the routing design of WMSN has higher requirements on the quality of service (QoS). This paper systemically analyzes the similarity between social network and WMSN, then designs a QoS trust estimation model based on social network analysis, which enables each sensor node measuring the service quality by monitoring the behaviors of neighbor nodes. An energy efficient QoS assurance routing based on cluster hierarchy (EEQAR) is proposed to achieve energy efficiency and meet the requirement of QoS. To obtain a better performance, EEQAR routing adopts cellular topology to form the cluster structure and balance the energy consumption by structure movement. The simulation results show the high performance of EEQAR routing in lifetime and quality of service.
IEEE Systems Journal 01/2012; · 0.92 Impact Factor
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ABSTRACT: Relay selection schemes for cooperative communications to achieve full cooperative diversity gains while maintaining spectral and energy efficiency have been extensively studied in a recent research. These schemes select only the best relay from multiple relaying candidates to cooperate with a communication link. In the present paper, we reviewed recently proposed cooperative communication protocols that integrate with relay selection mechanisms. The key design issues for relay selection mechanisms, for example, relaying candidate selection, optimal relay assignment, and cooperative transmission, were identified. We further discussed the challenges of optimal relay assignment in multi-hop wireless sensor networks and presented the potential applications of cooperative communications with a relay selection in such networks. Future research directions were outlined, for example, the issues of service differentiation and system fairness in cooperative communication systems and the joint use of game theory and adaptive learning techniques in relaying candidate selection and optimal-relay assignment mechanisms for efficient allocation of network resources. Copyright © 2011 John Wiley & Sons, Ltd.
Wireless Communications and Mobile Computing 05/2011; · 0.88 Impact Factor
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Wireless Communications and Mobile Computing. 01/2011; 11:1646-1656.
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IEEE Systems Journal. 01/2011; 5:495-505.
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ABSTRACT: To achieve full cooperative diversity gains while still obtaining spectral and energy efficiency, cooperative communications with relay selection schemes, i.e., only the best relay is selected from multiple relaying candidates to cooperate with the communication, have been extensively studied in recent research. In this paper, we review the recent research on optimal relay assignment for cooperative communications, and investigate the use of cooperative communications with adaptive relay selection for soft QoS provisioning in resource-constrained wireless sensor networks. We propose EEARS, an energy-efficient adaptive relay selection scheme, which is based on a multi-agent reinforcement learning framework. In EEARS, optimal relays, in terms of outage probability, spectral and energy efficiency, are selected distributedly from multiple relaying candidates to participate in the communication, without the needs of prior knowledge of the wireless network model and centralized control. Simulation results show that EEARS fits well in dynamic environments, and is effective in improving the satisfying level of soft QoS provisioning for WSNs, i.e., increasing the spectral and energy efficiency, and reducing the amount of time that QoS violation occurs, by exploiting spatial and time diversities. Furthermore, compared with schemes using fixed transmitting power, EEARS can achieve a higher energy efficiency by varying the transmission power level according to wireless channel conditions.
Communications and Networking in China (CHINACOM), 2010 5th International ICST Conference on; 09/2010
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ABSTRACT: Cooperative communications have been demonstrated to be effective in combating the multiple fading effects in wireless networks, and improving the network performance in terms of adaptivity, reliability and network throughput. In this paper, we investigate the use of cooperative communications with adaptive relay selection for resource-constrained wireless sensor networks, and propose QoS-RSCC, a QoS-support multi-agent reinforcement learning based relay selection scheme for cooperative communications. In QoS-RSCC, optimal relays, in terms of outage probability and channel efficiency, are selected distributedly from multiple relaying candidates for the intermediate routers along the multi-hop route, without the needs of prior knowledge of the wireless network model and centralized control. We compare the network performance of QoS-RSCC with CRP, and investigate the impacts of network traffic load, channel bit error rate, and node's mobility on the network performance. Simulation results show that QoS-RSCC can achieve a near-optimal performance on both diversity gains and channel efficiency, and fits well in dynamic environments.
Global Telecommunications Conference, 2009. GLOBECOM 2009. IEEE; 01/2010
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IJSNet. 01/2010; 8:98-108.
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ABSTRACT: In this paper, we investigate the use of cooperative communications for reliable data dissemination in wireless sensor networks. We first identify the disadvantages of some existing cooperative schemes. While the previously proposed ldquomulti-hop mesh cooperative transmission structurerdquo addresses these disadvantages, it suffers from large end-to-end delays during data disseminations due to its random value-based forwarding node selection scheme. This paper proposes a novel distance-based forwarding node selection scheme that yields smaller end-to-end delays. We present extensive simulation results that verify the effectiveness of the proposed data dissemination scheme.
Advanced Communication Technology, 2009. ICACT 2009. 11th International Conference on; 03/2009
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Proceedings of the Global Communications Conference, 2009. GLOBECOM 2009, Honolulu, Hawaii, USA, 30 November - 4 December 2009; 01/2009
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Ad Hoc Networks, First International Conference, ADHOCNETS 2009, Niagara Falls, Ontario, Canada, September 22-25, 2009. Revised Selected Papers; 01/2009
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ABSTRACT: Biomedical sensor networks have been widely used in medical applications, where data packets usually contain vital sign information and the network used for communications should guarantee that these packets can be delivered to the medical center reliably and efficiently. In other words, a set of requirements for quality of services (QoS) must be satisfied. In this paper, RL-QRP, a reinforcement learning based routing protocol with QoS-support is proposed for biomedical sensor networks. In RL-QRP, optimal routing policies can be found through experiences and rewards without the need of maintaining precise network state information. Simulation results show that RL-QRP performs well in terms of a number of QoS metrics and energy efficiency in various medical scenarios. By investigating the impacts of network traffic load and sensor node mobility on the network performance, RL-QRP has been proved to fit well in dynamic environments.
Applied Sciences on Biomedical and Communication Technologies, 2008. ISABEL '08. First International Symposium on; 11/2008
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ABSTRACT: In this paper, we present MRL-QRP, a multi-agent reinforcement learning based routing protocol with QoS support for wireless sensor networks. In MRL-QRP, sensor node cooperatively computes QoS routes using a distributed value function - distributed reinforcement learning algorithm (DVFDRL). Global optimization can be achieved by using locally observed network information and limited exchanging of state values with immediate neighboring nodes. We compare the network performance of MRL-QRP with QoS-AODV, an on demand QoS support routing protocol. The impact of network traffic load and sensor node¿s mobility on the network performance are investigated, simulation results show that MRL-QRP performs well in respects of a number of QoS metrics and fits well in highly dynamic environments.
Wireless Communication Systems. 2008. ISWCS '08. IEEE International Symposium on; 11/2008
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ABSTRACT: This paper considers the centralized spectrum allocations in resource-constrained wireless sensor networks with the following goals: (1) allocate spectrum as fairly as possible, (2) utilize spectrum resource maximally, (3) reflect the priority among sensor data, and (4) reduce spectrum handoff. The problem is formulated into a multi-objective problem, where we propose a new approach to solve it using modified game theory (MGT). In addition, cooperative game theory is adopted to obtain approximated solutions for MGT in reasonable time. The results obtained from numerical experiments show that the proposed algorithm allocates spectrum bands fairly with well observing each sensor's priority and nearly minimal spectrum handoffs.
Proceedings of the 68th IEEE Vehicular Technology Conference, VTC Fall 2008, 21-24 September 2008, Calgary, Alberta, Canada; 01/2008
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ABSTRACT: Relay selection schemes for cooperative communications to achieve full cooperative diversity gains while maintaining spectral and energy efficiency have been extensively studied in recent research. These schemes select only the best relay from multiple relaying candidates to cooperate with a communication link. In this paper, we review recently proposed cooperative communication protocols which integrate with relay selection mechanisms. The key design issues for relay selection mechanisms, e.g., relaying candidate selection, optimal relay assignment, and cooperative transmission, are identified. We further discuss the challenges of optimal relay assignment in multi-hop wireless sensor networks, and present the potential applications of cooperative communications with relay selection in such networks. Future research directions are outlined, e.g., the issues of service differentiation and system fairness in cooperative communication systems, and the joint use of game theory and machine learning techniques in relaying candidate selection and optimal relay assignment mechanisms for efficient allocation of network resources.
Commun. Mob. Comput. 01/2007; 00:1-16.
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ABSTRACT: The integration of biomedical sensors with wireless net-work technology may have great potentials in medical ap-plications. In this paper, we investigate the use of the IEEE 802.15.4 standard in an ECG monitoring sensor network and study the effects of CSMA/CA mechanism, number of network devices, sampling rates and transmitting cycles. The performance of the network is analyzed in terms of transmission delay, end to end latency, and packet delivery rate. Both biomedical signal sampling time and transmis-sion delay contribute to the end to end latency, but the end to end latency is mainly introduced by signal sam-pling time, especially for low data rate biomedical sensors. The packet delivery rate increases when the number of pay-load data becomes large due to high channel efficiency and packet coding efficiency, but large size packet suffers high end to end latency. In our case study, for a full size MAC packet with maximum payload size (114 bytes), the aver-age end to end latency introduced by sampling and trans-mitting is about 90 ms. For time-critical applications, a payload size between 40 and 60 bytes can be a good choice, due to lower end to end latency and acceptable packet de-livery rate. In the design and deployment of biomedical sensor networks in time-critical medical care applications, trade-off between end to end latency and packet delivery rate must be considered.
