Research on Public Access Networks Based on Bluetooth technology (1)

Bluetooth is an open and short-distance wireless communication technology standard. It is used to achieve wireless network interconnection between fixed devices and mobile devices in a small range [1]. The LAN access section of Bluetooth SIG specifies the specific functions and processes used by LAN access applications at each protocol layer. A single or multiple data terminal (DT) uses a LAN Access Point (LAP) to connect to the LAN wirelessly. This section is limited to a distance of only 10 m between the LAP and DT micronetwork (Piconet), and cannot achieve seamless Internet access for mobile terminals in the broad sense. TCP/IP is designed based on the assumption that the terminal device is fixed. The TCP/IP-based high-level protocol cannot meet the requirements of terminal mobility. Therefore, how to achieve seamless Internet access for Bluetooth mobile terminals has become a hot topic in the communication field.

The Bluetooth Public Access network Protocol (bluepac ip, Bluetooth Public Access Internet Protocol) supports IP services based on the Bluetooth technology.

1 research on the concept protocol of BLUEPACIP

Consider whether the bluetooth device connected to the BLUEPAC network has its own IP address. In addition, the BLUEPAC network should support both mobile devices and static devices.

All devices in the BLUEPAC lan must use the BLUEPACIP, and the devices outside the BLUEPAC area can communicate with the IP host outside the area without any modification.

1. 1. Refer to the Network Structure

The network structure of the BLUEPAC reference is similar to that of the cellular network [2], 1 shows. It consists of the following five parts.

1 Gateway (GW)

In the BLUEPAC area, the gateway connecting the bluepac lan to the public network is provided to the Global Information and Communication Service, and the corresponding IP Protocol configuration of the bluetooth device.

2 bluetooth device　

A Bluetooth device is a terminal device of a Bluetooth user, such as a laptop or PDA.

3 Bluetooth Base Station

Connects Bluetooth devices to the BLUEPAC network to provide network layer services for Bluetooth devices. The exchange between the base station and the device is mainly completed at the data link layer.

4 BLUEPAC proxy

Complete the dynamic configuration of the Bluetooth Network. Only Bluetooth communication devices configured with IP addresses in the BLUEPAC network can send and receive IP packets normally. Due to the high mobility of devices in the Bluetooth Network, the fixed IP address-based configuration method may cause difficulties in packet routing. Therefore, the Bluetooth proxy server uses the Dynamic Host ConfigurationProtocol protocol to configure IP addresses for Bluetooth devices. When a new Bluetooth device is added to the network, you also need the Bluetooth proxy server to complete the configuration. Note that if a device in the BLUEPAC network uses a local address for the local network, rather than a valid IP address, the proxy server needs to convert the address.

5 Base Station Controller

It is used to connect the gateway and some base stations and send data and control information to the base stations.

The basic process of BLUEPAC Bluetooth terminal access is: Within the Bluetooth radio wave range, users can access bluepac lan through the BLUEPAC base station to obtain services or access the public network. To expand the LAN coverage, you can also establish several micro networks and connect the micro networks to the LAN through the BLUEPAC base station, which is very helpful for achieving full coverage of the communication area. The network structure 1 is shown in. When a Bluetooth micronetwork is exceeded, you can access the BLUEPAC service by connecting to the next BLUEPAC base station.

 

For the movement of BLUEPAC terminal devices, the BLUEPAC reference network structure can also provide continuous services, as shown in 1. The BLUEPAC Device of mediainnet has established a connection with the application server. When the BLUEPAC terminal device enters the left-side Weaver network from the middle, the BLUEPAC agent removes the middle connection and establishes a new connection with the left-side BLUEPAC base station. During network switching, the old base station will not only save the current connection status and information, but also forward the information to the new base station, and require that communication interruption or service volume decrease during network switching.