SUMMARYIn this paper, we propose a distributed topology management algorithm, named T-Must, which orchestrates coalition formation game between camera and scalar sensor (SS) nodes, for use in wireless multimedia sensor networks. In the proposed solution, connectivity among the peer camera sensor (CS) nodes is maintained, and coverage is ensured between them. Only the scalar data are not sufficient to describe an event in a particular monitored area. In many cases, multimedia data (specifically, video data) are required to provide more precise information about the event. As the CS nodes, which sense and transmit multimedia data, are costlier than the SS nodes, the former are deployed in the monitored area in lesser numbers compared to the latter ones. In case of CS nodes, power consumption due to sensing is also significant, similar to power consumption for the transmission and reception of packets. Therefore, in this work, in order to increase the network lifetime, topology is controlled by forming coalition between the CS and SS nodes. Upon occurrence of an event, the SS nodes send scalar data to their associated CS nodes. If the scalar data received from SS nodes cross a preconfigured threshold, the associated CS node in the coalition starts sensing the event, captures the video data, and forwards the video data toward other coalitions or sink.

A distributed topology management scheme in wireless multimedia sensor networks (WMSNs) ensures coverage of an event, prolongs network lifetime, and maintains connectivity between camera sensor (CS) nodes. However, the deployment of WMSNs in unattended environments makes the nodes vulnerable to security attacks. Hence, security issues should be considered, along with topology management, in WMSNs. In this work, we propose a trust-based distributed topology management scheme, named TRAST, for use in WMSNs. TRAST exploits the received signal strength of the control packets, which are then used to construct the distributed topology. In a non-secure distributed topology, the use of trust helps in providing coverage of an event, and maintaining connectivity, even in the presence of malicious attacks. The proposed topology management scheme achieves higher average coverage ratio and average packet delivery ratio than those corresponding to the LDTS and T-Must schemes, in the presence of malicious attacks.Index Terms-Wireless multimedia sensor networks, node replication attack, trust, received signal strength. ! 0018-9340 (c)

Wireless Multimedia Sensor Networks (WMSNs) involving camera and Scalar Sensor (SS) nodes provide precise information of events occurring in the monitored region by transmitting video packets. In WMSNs, it is necessary to provide coverage of events occurring in the monitored region for longer durations of time. The Camera Sensor (CS) nodes provide the coverage of an event and transmit the video data to the Base Station (BS), when these nodes are actuated by the associated SS nodes on occurring of an event. Therefore, in the existing pieces of work, distributed actuation focuses on the coverage of an event and prolongation of the lifetime of the CS nodes. However, for distributed actuation of the CS nodes, the SS nodes play a vital role. When the data sent by the associated SS nodes in an event area exceed the preconfigured threshold, the CS nodes start sensing the event and send the video data to the BS. Therefore, in addition to the lifetime of the CS nodes, the lifetime of the SS nodes and their data reporting latencies are important aspects for distributed actuation of the CS nodes, while sending both the video and scalar data to the BS. In this work, we propose a topology management-based distributed camera actuation scheme, named TADA, to prolong the lifetime of SS nodes, and decrease the data reporting latency in event area only. The increased lifetime of the SS nodes, in turn, increases the event coverage and packet delivery ratio. To increase the lifetime of the SS nodes in an event area, the SS nodes with the most residual energies are selected as the packet aggregators. In addition, the transmission range of these nodes is decreased, and in-network packet aggregation is performed, while reporting the happening of an event to the associated CS nodes. The aggregator selection mechanism helps in balancing energy consumption of the SS nodes. Similarly, the decrease in transmission range and aggregation mechanism help in decreasing energy consumption of these nodes. The transmission range of the SS nodes is decreased using social network analysis and Coalition Formation Game (CFG). CFG also helps in decreasing the data reporting latency of an event by the SS nodes to their associated CS nodes. Performance evaluation results show that the proposed scheme, TADA, which is based on the distributed topology management protocol named T-Must, achieves high performance in terms of the lifetime of the SS nodes, data reporting latency, coverage ratio of the event, event reporting credibility index, and packet delivery ratio in an environment affected by shadow fading.

No abstract