Design of a Huffman Data Encoder Architecture

Wireless sensor networks (WSNs) are important in today's technology for helping to monitor our environment. WSNs are widely used in military, medical and industrial environments. It is capable of monitoring, collecting and transmitting data to a primary server wirelessly. Wireless sensor nodes are powered by a limited energy supply such as a small battery or an energy harvester that generally produces a small amount of energy. To extend the lifetime of the device, energy consumption must be reduced. Data transmission is known to consume the largest percentage of energy in a sensor node. One method for reducing energy is by compressing the data prior to transmitting it. This study analyses the performance of the Huffman architecture in terms of compressing data that are commonly used in wireless sensor nodes. The primary module in the architecture comprises a data retriever, frequency calculator, probability calculator, Huffman tree generator and Huffman code generator. From the experimental results, the Huffman circuit architecture simulation consumed 51394 clock cycles to completely compress 366 data samples, using 3.729mW of power consumption. Based on a 20MHz clock frequency, this is equivalent to 9.5824 mu J of energy consumption. Based on our analyses, the Huffman tree generator consumed the most power at 1.184mW, equivalent to 31.75% of overall power consumption.