ABSTRACT
CONTENTS 11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 11.2 Wireless Sensor Network Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 11.3 Data Aggregation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
11.3.1 Tree-Based Data Aggregation Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302 11.3.2 Cluster-Based Data Aggregation Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306 11.3.3 Multipath-Based Data Aggregation Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . 309
11.4 Secure Data Aggregation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309 11.4.1 Secure Data Aggregation over Plain Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 11.4.2 Secure Data Aggregation over Encrypted Data . . . . . . . . . . . . . . . . . . . . . . . . . 314
11.5 Open Research Issues and Future Research Directions . . . . . . . . . . . . . . . . . . . . . . . . . . 318 11.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Wireless sensor networks often consist of a large number of low-cost sensor nodes that have strictly limited sensing, computation, and communication capabilities. Due to resource-restricted sensor nodes, it is important to minimize the amount of in-network data transmission so that the average sensor lifetime and the overall bandwidth utilization
are improved. In wireless sensor networks, data aggregation is the process of summarizing and combining sensor data in order reduce the amount of data transmission while increasing the reliability of the data. This chapter surveys the current state-of-the-art data aggregation techniques in wireless sensor networks. In the first part of the chapter, data aggregation protocols are categorized into two parts regarding their network topology. Then, the interaction between data aggregation and security protocols is investigated as they both are essential for wireless sensor networks. In the last part of the chapter, the open research areas and future research directions in data aggregation problem are presented.
