A Study On LDPC Code And Implementation On Wireless Sensor Networks

Wireless sensor network is a special Ad hoc network with the form of radio frequency communication, and consists of a large number of small, low cost and resource-constrained of sensor nodes. it can make sense of the information within the network target environment, and then transmitted to the user. Wireless sensor networks are self-organized, data-centric and distributed cooperation. Sensor nodes are resource-constrained in the computing, storage, transmission bandwidth, power consumption, etc. Among them, especially energy consumption is the most serious problem, because of the large quantities, junior shapes, low cost and complex distributed environment of the nodes, the nodes have to carry a limited supply of energy, but also one-off, which makes the reasonable allocation of energy to try to extend the network life cycle for wireless sensor network faces the biggest challenge.At present, with the large scale integrated circuit technology advances, the energy consumption of the processor and the sensor module is almost negligible, and wireless communication is the major power energy consumption, therefore, the bottleneck of wireless sensor network is wireless communication. As long as the reduced energy consumption of wireless communication, wireless sensor networks will greatly extend the life cycle. For a given signal to noise ratio, the smallest error rate is the key factor of reducing the energy consumption of wireless communication module, and channel coding is an important means to reduce the error rate.Bases on these characteristics of wireless sensor networks, we proposed to use LDPC codes for error control in wireless sensor networks. Then the concept, characteristics, structure, structure method of check matrix and encoding and decoding algorithms of LDPC are analyzed. The effects of the decoding algorithms and code length of LDPC codes are simulated.Based on the error control of the energy model, we found that LDPC codes used over the wireless sensor network has higher energy efficiency and link reliability than does not use channel coding for wireless sensor networks. The MCUs employed in WSN nodes are Atmega128L and the low power radio frequency (RF) integrated circuits (ICs) are CC1000. In the unique operating system named TinyOS, of which in the wireless sensor network, we realized the LDPC codes in practical applications of wireless sensor networks. And we can find through the simulator named Avrora, that LDPC codes is much better than does not use codes for wireless sensor networks, regardless of the energy efficiency, the effective transmission distance or transmission efficiency.