Design And Implementation Of 3g Subsystem In Iad System

With the extensive application of third generation (3G) mobile communication technology, more and more embedded devices begin to support 3G. Integrated access device (IAD) that integrate many kinds of network access manners also need to support 3G. The precondition of IAD accessing 3G networks and running 3G applications is the success of 3G dial-up. Excellent design of 3G subsystem helps to promote performance and extend function of IAD.Linux operating system is platform of the system. Many kinds of practical technology and Linux kernel knowledge were used to implement 3G dial-up function, such as I/O multiplexing, shared memory, semaphore, socket and so on. The demands of 3G dial-up were comprehended by analyzing the client's demands. The architecture was designed by analyzing many functions of IAD system. Every public function in big functions was designed to a module. Every big function was implemented by several modules. 3G subsystem was implemented by five modules. They were designed and implemented with using many kinds of technology. The design and implementation of memory data model, message routing and hardware monitor are the most important things.3G subsystem was implemented and tested, but there was a defect in the design and implementation of it. This defect led to a performance bottleneck of the entire IAD system. A method was proposed by analyzing the reason of this defect. The defect was corrected by modifying the USB serial driver in kernel and some related modules, and the performance of system was improved. Modifying the other USB drivers in kernel by imitating the method can further improve the performance of system. To make more economic benefits, the application can be extended by adding more 3G applications to the system.