The Study For Data Gathering And Data Aggregation In Wireless Sensor Networks

Wireless sensor network consists of a large number of sensor nodes that are deployed in the monitoring area to obtain valid information. Studies have shown that transmitting energy consumption is the main part of the energy consumption of sensor nodes. It is of most importance that reducing transmitting energy consumption and data redundancy. Data aggregation is one of efficient approaches to reduce energy consumption and to prolong the lifetime of wireless sensor network. However, combining data aggregation approach and routing to design efficient routing protocol is of great importance. This paper summarized data aggregation algorithms of wireless sensor networks, analyzed and compared the advantages and disadvantages of typical routing protocols.We proposed two data gathering and aggregation approaches for grid-based wireless sensor networks based on the features and applications of wireless sensor networks.(1)Chain-based data aggregation for grid-based wireless sensor networks. The network is divided into a number of uniform grids. We assigned different weights for sensor nodes based the residual energy and the distance to the center of the grid. The sensor node that has the largest weight is selected as the grid head. The grid head is responsible for collecting and aggregating data from other nodes within the grid. The grid heads formed into a closed chain by a specific rule. The grid head that have the largest energy and the smallest distance to Sink node is selected as chain head responsible for transmitting data with Sink node. Simulation results show that the proposed algorithm can reduce energy consumption and extend the lifetime of wireless sensor networks.(2)Grid-based data aggregation based on mobile sink in wireless sensor networks. The network is divided into several grids based on the geographic information. The sensor nodes in the same grid are linked into a chain based on greedy algorithm. Each chain has a head node and an end node, the chains of the grids that have the same ordinate are linked into a longer chain responsible for sending aggregated data to the corresponding Sink node. Simulation results show that the algorithm can effectively reduce energy consumption and improve network performance.