OLDA: An Efficient On-Line Data Aggregation Method for Wireless Sensor Networks

Sending and receiving redundant packets in Wireless Sensor Networks (WSN), increase the congestion ratio as well as energy consumption in WSNs. In this regard, several data aggregation methods for WSNs have been presented to identify and to aggregate redundant packets. In this paper, we present an efficient on-line data aggregation method, OLDA, for real-time WSNs. OLDA method assigns different priorities to different events to help Cluster Head (CH) nodes in making an appropriate decision about the packet i.e., forwarding or aggregation. Indeed, CH nodes send newly received packet with probability 1-p and remove it with probability p. Since the parameter p is proportional to time and location of the occurred event, OLDA method, tends to forward packets of newly occurred events i.e., p is close to 0 here. When more time is passed parameter p is gradually increased, hence OLDA method tends to drop packets. Experimental results by the use of NS2 simulator show that OLDA method effectively reduces the miss rate compared with DASDR and RDAG aggregation methods. Also, OLDA method aggregates more than 70% of redundant packets and reduces the network end-to-end delay compared with RAG and SPEED methods.