Implementation Of Hands-Free Profile In Windows CE Based On Bluetooth Prototol Designing

Bluetooth technology is one of the short-range wireless communication technologies which can transmit voice and data at the same time.The main purpose of Bluetooth technology is to replace the current cable connection.Bluetooth device works in the ISM band(2.4GHz).In Bluetooth specification version 1.2,the baseband data rate is 1Mb/s.The most significant characteristics of Bluetooth technology are miniaturization,low cost,low power consumption and convenience.The Bluetooth specifications made by Bluetooth Special Interest Group(SIG) provide technical standards and requirements which should be met.The specifications include Bluetooth protocols and Bluetooth profiles.The Hands-Free Profile,which has realized the wireless connection between Bluetooth hands-free unit and audio gateway,allows drivers to make and receive phone calls while driving.It will avoid the traffic accident caused by inconvenience.This article analyzes Bluetooth core protocols and Bluetooth Hands-free Profile at the beginning.Then,the article has used CSR's Bluetooth chips(BC3) to develop Bluetooth hands-free application program.The application program is based on Bluetooth protocols developing under Windows CE embedded operating system.The paper includes the following contents:Firstly,it analyses the characteristics and developing situation of Bluetooth technology.As a basis for this,the article summarizes the significance of developing Bluetooth hands-free application program based on Bluetooth protocols developing.Then,it makes detailed analysis of the four core protocols(HCI,L2CAP,SDP and RFCOMM) of Bluetooth in Hands-free Profile.The analysis of frame structure,the data and event processing are the keys of the Bluetooth Protocol developing.On the basis of the Bluetooth protocol theory,the article has designed software development process and the detailed methods of Bluetooth core protocols.Then it has described the important data structures and functions of the application program in detail.The upper layer has realized Bluetooth Hands-free application program using the interface functions provided by Bluetooth protocol stack. The application program can realize communication functions of devices searching, controling volume,pairing devices,answering phones,dialing,etc.The article uses Microsoft eMbedded Visual C++ 4.0 to develop Hands-free application program under Windows CE 5.0.The application program based on Windows CE is generated after editing code,compiling and debugging.Then it will be placed into the nandflash of the vehicle navigation system together with resource files used by the program.After repeated testing,the protocol program and the application program designed by this article can realize a stable voice and data transmission between Bluetooth devices.