Design And Implementation Of Embedded Internet Access Platform Based On Cdma

With the development of communication, Internet and computer technology, mobile communication is no longer localized in voice service. The combination of embedded technology and mobile communication technology accelerates the development of embedded Internet.This thesis designs and implements the Embedded Internet Access Platform based on CDMA, and presents a scheme for embedded system to access Internet via wireless network. In this scheme, traditional embedded system can be located in anyplace with CDMA, especially in the bad environment which is not suitable for wiring.The thesis analyzes the principle of Internet communication based on CDMA and studies the key techniques, such as CDMA and PPP protocol and so on. On the basis of these studies, an embedded wireless communication platform which includes integrated PPP and TCP/IP protocols is designed and implemented. The platform regards S3C44B0 as kernel, wireless modem from ZhongXing as CDMA communication module, RTEMS as the OS, implements wireless communication by using PPP protocol on RTEMS. RTEMS is a lightweight, real-time and open source operating system used widely in real-time control domain. Abundant APIs are supplied by this platform to give facility for the design of various control systems.Detailed design and implementation include the BSP for S3C44B0, bottom communication module which is based on PPP protocol for the RTEMS real-time operating system and some test cases. The bottom communication module is divided into three parts which includes bottom communication interface, PPP Daemon and PPP dummy driver. Bottom communication interface is used to communicate with CDMA network; PPP Daemon is responsible for link creation and network configuration; PPP driver is used as the bottom protocol to encapsulate and analyze the packets as well as to transmit the packets.The scheme implemented by this thesis has high reliability, convenient interface, high integration density and well real-time characteristic, while the cost is low.