# Multi-Device to Multi-Device (MD2 MD) Content-Centric Networking Based on Multi-RAT Device
## 3 Proposed Method
### Proposed Method  
This paper proposes a method of transmitting and receiving device information using the broadcasting abilities of Bluetooth Beacon. Bluetooth Beacon includes detailed information for a device, such as CCNx support, the owned content, and the communications interface.  
In the case of a WLAN connection between devices, the connection process between CCNx-enabled devices that utilize the proposed method is as shown in Figure 5. When the host device (which creates the AP) transmits information using Bluetooth Beacon, another device that attempts to connect to the AP receives the Bluetooth Beacon signals transmitted by the host device. The device attempting to connect to the AP checks whether the host device supports CCNx, and then subsequently establishes a CCNx connection by connecting to the AP based on the SSID and IP information received via the Bluetooth Beacon signal. Furthermore, it is possible to select and connect the most optimal AP or device by comparing the information for all the Beacon signals received. Because the proposed method transmits the information required for establishing a connection using Bluetooth Beacon, a connection can be established between devices quickly, without a physical connection between those devices.  
Figure 4: Existing process for connection between devices.  
The existing method can be divided into AP scan, AP connection, and AP disconnection processes. Upon the first connection attempt, AP scan and AP connection are performed, after which a connection is established, then AP disconnection and scan are performed again. When the number of connection attempts is \(X\), AP scan and AP connection are repeated \(X\) times in the existing method and AP disconnection is repeated \(X-1\) times. In the existing method, the time required to establish a connection with a target device can be determined from the following Equation (1):  
\[T_{Total}=(T_{AP\_Scan}+T_{Connect})\times X+T_{Disconnect}\times(X-1). \tag{1}\]  
In the proposed method, after a device receives the Bluetooth Beacon signals one at a time, if the device satisfies the user's requirements, then a method for connecting the AP and CCNx is implemented. Therefore, in the existing method, the average number of received Beacon signals is identical to the number of connection attempts. Suppose the average number of received Beacon signals is \(Y\); then, in the proposed method, after preparing to receive Bluetooth Beacon signals, \(Y\) Bluetooth Beacon signals are received. After that, the \(AP\) connection is performed. In the proposed method, the time consumed for connecting to a target device is expressed by the following Equation (2):  
\[T_{Total}=T_{Beacon\_Scan}\times Y+T_{Connect}. \tag{2}\]  
With the existing method, each time an attempt is made to connect to another device, the entire process is repeated. In the proposed method, since only the Bluetooth Beacon scan process is repeated, the repetition of any unnecessary processes does not occur.  
In BLE, the advertising and scan processes are performed by using only the three channels in the 2.4 GHz band. For this reason, the BLE scan process consumes less time than that of WLAN.