Abstract: In wireless sensor network communication,sensor data need to be sent to the host computer through the wireless device.With the increase of the amount of data needed to be transmitted by the terminal sensors,the energy consumption of wireless devices is gradually increasing.A complex environment that is not convenient for timely maintenance lead to premature failure of wireless communication equipment and communication interruption.Therefore,it is necessary to compress the data collected by the sensor to reduce the amount of data sent.Based on the analysis of sensor data characteristics and traditional LZW (Lempel-Ziv-Welch) compression algorithm,an improved LZW algorithm for wireless sensor network applications is proposed.Firstly,the algorithm preprocesses the adjacent data collected from sensor to calculate the difference,so as to improve the repetition rate of the data items.Then,the appropriate dictionary size is selected and the traditional order memory is replaced with the hash memory in the dictionary,so as to improve the way of dictionary updating.When the compression rate is decreased,the proposed algorithm updates the dictionary,and saves the common single character to release the dictionary space,for data compression.The experimental results show that compared with traditional LZW algorithm,the improved LZW algorithm reduces the compression rate of the ordered sensor data by up to 40%,and reduces the amount of data needed to send.The compression speed is also increased by nearly ten times,which proves that the improved LZW algorithm for wireless sensor network applications is effective and feasible.

Key words: Compression algorithm, Compression ratio, Data preprocessing, LZW algorithm, Wireless sensor network