.3 The Gbts Software System Design And Implementation Of Embedded Support Subsystem

With the rapid growth of the network application, network systems are required to be faster, support multi-media and various protocols. These increase the complexity of the embedded system of modern network devices. Embedded operation system support subsystem(OSS) is introduced into the network devices to reduce the difficulty of their software development. OSS is an extension of embedded hardware, which supports the development of application software.The software system of Base Station Transceiver Subsystem(BTS) is one of the large-scale distribute system in mobile communications field, which consists of many special modules.This paper takes example for one module in BTS system to introduce the design and implementation of OSS, which involves two kinds of the encapsulation.On the one hand, BSP encapsulates the hardware, includes the CPU and the peripheral chips. BSP supplies the simple interface to operate the peripheral chips conveniently. Thus, Real-Time Operating System(RTOS) can start up from the various hardware successfully and response to the asynchronous event opportunely.On the other hand, RSP implements the encapsulation to RTOS and brings up the process model according to the running character of the business layer, realizes the secondary process schedule inside task. RSP provides the upper business with process management and timer management. With the support of RSP, the business layer realizes the transplantability and the platform independenty.Besides, the paper also improves a serial communication protocol based on RS-485 data bus, and realizes the application. In this protocol, the transmitter organizes the frame according to it, and the receiptor does validity check of the characters, length check, CRC check. Thus, the system will work more exactly and efficiently. And based on RS-485 communication, the paper implements a process communication method, which is impulsed by overtime message of timers'check.