Ieee 802.15.4-based Wireless Usb System Design

In the age of network, with the boost of wired network applications, wireless technologies are also growing rapidly, because they are flexible and highly efficient. Under this circumstance, lots of wireless terminals, like wireless sensors and remote controllers, are created. Those devices do not need wideband for data transmission, but instead, short transmission delay and low power consumption are what they require to propagate the battery life and increase the number of units integrated in a device. Though Bluetooth [1] becomes very popular in the recent years, yet it is not the specific standard facing those low-end applications like sensors and controls. Its application asks for high performance processor and extra memory to offload the costs when establishing a network. On the contrary, Human Interface Devices (HID), like mouse, keyboard, gamepad and earphone, do not need a complex network. As a matter of fact, a simple, quickly constructed, less expensive point-to-point or point-to-multipoint network is necessary [2]. Wireless USB LS technique, which is on the basis of IEEE802.15.4 Standard, incorporated the plug-and-play feature of USB devices, thus can be used to connect the HID to the personal computer and remove those complicated cables from our desk.This essay will first introduce the background knowledge of Wireless USB and the target of the research. In the second and third chapter, the architecture of Wireless USB and its combination with traditional USB technology will be analyzed. Then, in chapter 4, we will move onto the stack architecture, as well as the self-defined MAC layer protocol implemented in the wireless USB LS system. The following chapter is the main focus of this dissertation. The contents of chapter 5 include the flow chart and Finite State Machine of MAC layer, as well as the realization of the functions of the whole system. The hardware platform and test results will be discussed in chapter 6. Oscilloscope, hardware emulator and bushound, which is a software for testing USB data flow, are used to check whether the actual performance of the system meet the predefined standards. The tests include the join and quit function of the devices, guarded time slot communication, USB data handling and the usability of HID devices. In the last chapter—chapter 7, this thesis will end up with conclusions and expectations. On the basis of fully understanding of the system requirements, the functions are defined; MAC Protocol is designed; Modules are partitioned in a top-down approach. Then the functions of Wireless Adapter and Devices, such as entry and quit of the network, Guarded Time Slot data transmission, host-device synchronization, are realized with C and Assembly language. Finally, codes are downloaded to the hardware platform and tested.