الفهرس 
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Abstract
Wireless sensor networks (WSNs) have recently captured increasing interest in communication system research, with many applications in monitoring physical environment. A wireless sensor network consists of many small sensor nodes distributed in a sensing area to aggregate the surrounding environmental data. The collected data are sent to a collection point called the sink node, which transmits the received data to a control station. The sensor nodes have many constraints such as limited power, limited bandwidth , limited processing time, and limited transmission range.
The limited power in the sensor nodes is considered as one of the most important challenges in a wireless sensor network, as the network lifetime mainly depends on the energy consumption of the sensor nodes. This motivated many researchers to study the data aggregation problem in wireless sensor networks, aiming to minimize the energy consumption without sacrificing the performance.
The power is consumed in sensor nodes during different processes such as the sensing process, computational operations in the sensor, and the transmission process.