# Multi-Device to Multi-Device (MD2 MD) Content-Centric Networking Based on Multi-RAT Device
## 1 Introduction
In step with the increasing trend in the use of mobile devices and large amounts of data, it is expected that the IoT environment will advance to organically communicate large-volume content between fixed devices and users' mobile devices. CCN is very well suited to applications such as a content-centric IoT environment based on mobile devices. However, previous studies on D2D have mainly dealt with intermittent transmission and reception of small amounts of data using short-range communication, mainly in devices such as sensors and IoTs. Therefore, in 5G mobile communication and the multi-device to multi-device (MD2 MD) network based on high-speed WLAN, the transmission and reception of a large amount of multimedia traffic between wireless nodes have not been studied yet. Also, in the case of existing studies, most of the studies focused on transmitting information from a large number of sensors to a specific sink/aggregator node. Thus, most assume a logical tree structure. In this paper, we consider the MD2 MD environment in which large-scale mobile stations communicate with each other and study the situation of transmitting and receiving a large amount of multimedia traffic considering the rapidly increasing amount of traffic in mobile communication. Particularly, in a multimedia traffic sending/receiving environment of a large number of terminals, multimedia content is considered to be exchanged through networking between terminals without accessing the Internet. To this end, we utilize content-oriented CCN technology and Bluetooth beacon technology beyond IP technology that performs host-centric communication with the Internet. Using Mobile CCN technology enables the Bluetooth beacon to be used for mutual search and content search between large-scale terminals and to know which content is located in which node in the network in the mobile networking environment of MD2 MD. In particular, the application of Mobile CCN technology in the MD2 MD environment in mobile communication/wireless communication networks is a very rare topic of study, and we believe that this study can be a basis for future research [12; 13; 14; 15]. In particular, considering the developing mobile terminal, we have studied its operation based on heterogeneous wireless technology using several different wireless technologies. The use of heterogeneous wireless technology also includes intelligent use, such as choosing a wireless link that matches the nature of the traffic, beyond simply raising the transmission rate using multiple wireless transmission links. Based on this background, this paper presents a discussion of MD2 MD Mobile CCN, whereby a mobile device configures a network by actively searching for nearby devices and then connecting to a device with the required content, based on autonomous MD2 MD communication and MobileCCN. In such an MD2 MD Mobile CCN environment, there are issues related to device discovery and connection between the mobile devices. To solve these issues, this paper proposes a method of transmitting and receiving device information by using Bluetooth Beacon, more commonly known as iBeacon. In this paper, we propose a technology to reduce the connection time and content query time by acquiring the content information of wireless codes before accessing and connecting to the terminal with the desired content, in addition to technology development that reduces connection time using Bluetooth Beacon. Also, we propose a technique to reduce query time through Mobile CCN between remote terminals. Our method enables rapid multimedia communication in an MD2 MD networking environment that transmits/receives a large amount of multimedia traffic. In this paper, we implemented the proposed method in a real testbed. In particular, we used the CCNx open-source project for mobile, implemented the Raspberry Pi-based Multiple Radio Access Technology (Multi-RAT) node directly, measured the performance of MD2 MD, and showed that the proposed method is effective.