Design And Implementation Of Voice Transmission System In Wireless Sensor Networks

Wireless Sensor Networks is a kind of new rapid developed technology since 2000, It combines sensor technology, embedded computing technology, wireless communication technology, computer network technology, distributed information processing technology, Real-time monitoring, sensing and control of the monitoring object, As the widely used of wireless sensor network technology, the traditional gathering information such as temperature and humidity are no longer able to match the requirements of various applications, So the voice, images, video and other multimedia information of environment and the exact location information integrated into wireless sensor networks has become a recent research focus, It have a great development of wireless multimedia sensor networks, and wireless sensor network positioning and tracking technology.This paper focus on technology development project of Jilin Province:"Based on wireless sensor networks located in the tracking system underground staff (20090425), Based on wireless sensor network technology, designed and developed applications in underground communications system for voice transmission, The system overcoming issues such as data acquisition expensive and the poor underground communication and environmental, to achieve voice communications, data collection function underground in this system.System consists of a fixed location in the underground layout of the active router, coordinator, and the voice nodes who carried by the miners. According to the actual situation of underground mine, we choose the clusters structure of three topology type of the network topology, coordinator node (base station) is placed on the exit tunnel of ground, routers is placed in a fix location of each floor tunnel, coordinator and router nodes's supplied by the wired power system.Voice nodes with battery power supply are carried by miners when they are working underground, in case of emergency nodes can communicate via voice transmission system. The system provides a low-power automatic routing protocol, node collect voice information and wireless transmission, multi-hop routing to the control center, to achieve the transmission of voice data and other functions.This article gives details about low-power hardware and software design of voice nodes. The design of the voice nodes produced mainly build up by the TI CC2530 and CML CMX618 voice codec chips. CC2530 is a true system-on-chip, including the performance of the first RF transceiver, industry-standard enhanced 8051 MCU, the system programmable Flash memory,8KB RAM, and many other powerful features, especially in low-power consumption performance significantly, System to meet the demand. CML CMX618 is a British company launched an integrated voice codec chip, at a low bit rate codec processing, and to ensure high voice quality. As CMX618 built-CODEC module, its internal integration of the A/D and D/A conversion, channel filtering, gain adjustment and other functions, sufficient to meet the sampling of analog voice, quantitative indicators such as operational requirements. Therefore, no further external A/D, D/A chip, the design also saves a lot of physical space. CC2530 and CMX618 are connected via SPI bus in order to transmit voice data and control commands, while considering the actual application requirements, CC2530 external buzzer is connected to the module, and also the key interaction module, power module, LED indication module. The details of embedded software are also described.Based on TI's free ZigBee protocol stack ZStack-CC2530-2.3.1-1.4.0, we design, implement and debug through all the code on the independent node hardware platform, and on this basis, developed a self-designed voice and data transmission Protocol-fallback strategy for improved sliding window protocol, the practical application of this method is for the improvement of the sliding window protocol, and voice in wireless sensor networks nodes to achieve. In this paper, the detailed process design of the transmission, and the error control and flow control are described.Finally, we described in detail about IEEE802.15.4 Sniffer system, and the usage of the system. The voice transmission system's performance is analyzed by Sniffer system, Respectively, the transmission distance, packet loss rate, node power, the voice data transmission efficiency of the experiment, the design of such systems are given guidance.