Marcelo Portela Sousa

Scalability in an adaptive cooperative system for wireless sensor networks

The performance of wireless sensor networks (WSNs) can be significantly improved using adaptive cooperative diversity (SCA) technique, which is basically a cross-layer design that combines truncated ARQ at the link layer and cooperative diversity at the physical layer. LEACH is a protocol for wireless sensor networks that utilizes randomized rotation of local cluster heads to evenly distribute the energy load among the sensors in the network. This paper proposes and evaluates the performance of a selective cooperative scheme for wireless sensor networks based on scalability. The evaluation of the lifetime and packet loss rate is presented and results based on the maximum number of retransmissions, network size, packet length and initial energy by nodes are provided. Our scheme shows better performance as compared to others.

LF-Ant: A bio-inspired cooperative cross-layer design for wireless sensor networks

In this paper, the authors propose the LF-Ant protocol for multi-hop wireless sensor networks, a cross-layer design inspired in the organized and collaborative behaviour of natural ants. At the network layer, the heuristic information is modelled by a fuzzy inference system to assist a cluster-head election and the routing process. A resultant relaying threshold is combined with an adaptive invoking of cooperative modulation diversity, at link and physical layers. Simulation results show the performance enhancement in network lifetime and packet loss rate, compared with another cross-layer cooperative system.

Ant colony optimization with fuzzy heuristic information designed for cooperative wireless sensor networks

Biologically inspired networking is becoming a very active area of research and development because methods from biology have attractive features such as scalability and resilience to changes in the environment. In this paper, the authors propose a cross-layer protocol for cooperative wireless sensor networks, inspired by the collaborative behaviour of ant groups. The fuzzy heuristic information modelling is proposed to assist the clustering and routing processes at network layer. A resultant relaying threshold is combined with an adaptive invoking of cooperative modulation diversity, at link and physical layers. Simulation results show the performance enhancement in network lifetime and packet loss rate, compared with another cross-layer cooperative system. The evaluation of energy consumption distribution and a comparison between the performance of fuzzy and crisp modelling are also provided.

Performance evaluation of a selective cooperative scheme for wireless sensor networks

Wireless sensor networks are becoming popular in many industrial and civilian application areas. The need is to improve the performance of such systems that can be significantly done by using adaptive cooperative diversity (SCA) technique, which is basically a cross-layer design that combines truncated ARQ at the link layer and cooperative diversity at the physical layer. In addition to it, LEACH protocol gives advantage of utilizing randomized rotation of local cluster-heads to evenly distribute the energy load among the sensors in the network. This paper proposes an integrated system, SCA with LEACH and evaluates its performance with LEACH with truncated ARQ system. Comparison is done based on network lifetime and packet loss rate of system under varying propagation scenarios, number of retransmissions, initial energy by node and network size. Simulation results show better performances with various achieved thresholds.

Cooperative Space-Time Block Codes for Wireless Video Sensor Networks

Wireless video sensor networks (WVSNs) are gaining popularity due to numerous potential applications such as video surveillance, environmental and habitat monitoring, and so on. Considering large-scale WVSNs, in which the sink node is not within the range of all other nodes, a multi-hop operation is desired. This paper proposes a novel cooperative system that uses space time-block codes to enhance the performance of multi-hop wireless video sensor networks. The proposed scheme is designed to deal with large-scale WVSNs, by adapting the cluster size and extending the cooperation between the cluster-heads. The performance comparison between the proposed system and a non-cooperative scheme is presented based on network lifetime for varying propagation scenarios, number of camera nodes, and on the quality of transmitted videos in a WVSN. Simulation results show an improvement in performance for the proposed system.

Low-Energy Selective Cooperative Diversity with ARQ for Wireless Image Sensor Networks

Wireless Image Sensor Network (WISN) is a type of sensor network, which has the ability of capturing, processing and transmitting images from a monitored enviroment. The need to improve the performance of such systems can be attained by using the Selective Cooperative diversity with ARQ (SCA) technique, which is basically a cross-layer design that combines Truncated ARQ at the link layer and cooperative diversity at the physical layer. In addition, the LEACH protocol has the advantage of utilizing randomized rotation of local cluster-heads to evenly distribute the energy load among the sensors in the network. This paper proposes an integrated system, SCA with LEACH, and evaluates its performance with LEACH with Truncated ARQ system. A comparison is obtained based on network lifetime, under varying propagation scenarios, and on the quality of transmitted images in a WISN, using both techniques. Simulation results show an improved performances for the proposed system.

Cooperative STBC with fuzzy election applied to surveillance wireless video sensor networks

Wireless video sensor networks (WVSNs) have obtained popularity due to numerous potential applications such as video surveillance, environmental and habitat monitoring, etc. Transmitting video over WVSNs requires large bandwidth as well as lifetime of sensor nodes long enough to fulfill the application requirements. This paper proposes an integrated system for WVSNs (mainly used for surveillance) that combines the use of adaptive cooperative diversity and fuzzy logic. The cooperative space-time block codes (STBC) are used to achieve full diversity with a simple maximum-likelihood decoding algorithm in order to enhance the performance of the considered WVSN. The performance comparison between the proposed system and a non-cooperative scheme is presented based on network lifetime, quality of transmitted videos, and required number of retransmissions under varying propagation scenarios in a WVSN. Simulation results show better performance for the proposed system.

Cooperative Modulation Diversity Applied to Heterogeneous Wireless Sensor Networks

The technology of Wireless Sensor Networks (WSNs) has been applied to automatic monitoring systems, and used in a wide variety of environments. In this paper, the authors evaluate the performance of a cooperative technique, applied to heterogeneous WSNs. The main contribution is the analysis of the impacts between the energy factor, the channel Signal-to-Noise Ratio (SNR) and the packet loss rate. The analysis also considers the energy consumption aspect. The cooperative modulation diversity performance is evaluated for different propagation scenarios and for two values of interleaving depth (K). A large value for K, leads the network to present lower values of packet lost rate. Some limiting conditions are obtained and the retransmission algorithm is discussed.