The Analysis And Realization Of HCI And L2CAP Protocol Of Bluetooth Wireless Communication System

As short-ranged wireless communications are used more and more widely nowadays. Bluetooth, which owns the merit of high security, is an inexpensive and effective solution of the short-range wireless communications. It is being applied in many aspects of daily work and life.It could be anticipated that Bluetooth will be an inevitable tool for people's life, just as the mobile telephone acts now. As a telecommunication protocol,Bluetooth wireless technology ensures communication compatibility worldwide,It provides an open-standard of wireless interface and control software with a low-cost,low-power consumption solution.With industrywide support, Bluetooth wireless technology free you from wired connections-enabling links between mobile computers, mobile phones, portable handheld devices. And connectivity to the Internet. Bluetooth uses the same 2.4GHz. frequency band as 802.11b does for wireless communication. It can now support the transmission speed of IMbps for data and voice.The Bluetooth Specification developed by SIG difines rules for implementation Bluetooth in almost all the aspects.lt includes two parts:Core Specification and Profile.Firstly the paper makes a survey of the development of Bluetooth technology in the internal and the external , explains characteristic and applications of Bluetooth, points out the purpose and significance of developing Bluetooth application. Secondly, based on the SIG Bluetooth specification versionl.l,it analyses the whole framwork of specification of Bluetooth technology and the contents of the Bluetooth protocol stack, expatiates the Host Controller Interface(HCI) and Logical Link Control and Adaptation Protocol Specification (L2CAP).About HCI protocol,this paper expatiates the format of the commands, events and data,and provides a practical illustration for every type.The process of initializing Bluetooth equipment, inquiring and requesting create a connection to other Bluetooth equipments, data transmission and disconnection is analyzed in detail, At last author presents flow diagram of software and the generic process of communication in the HCI layer, as for L2CAP layer,This paper expatiates four functions and three channels.the four functions are Protocol Multiplexing, Segmentation and Reassem-bly, Quality of Service and Groups.The three channels are connection- oriented channel,connectionless channel and singal channel.About the four functions of L2CAP ,this paper expatiates their actions, and how to realize them. About three channels of L2CAP, this paper expatiates their data packet format. This paper also analyses several main singling commands, and gives their data structure. In the end this paper presents flow diagram of software of L2CAP Layer.