With the enhancement of the functionality and practicality of smart phones, more and more users are used, especially for "mobile" business people. At present, competition in the smartphone market is also fierce. On the one hand, traditional giants such as Nokia, Motorola, and Samsung want to firmly grasp the market share. On the other hand, new international giants such as Microsoft, Apple, and Google have also begun to enter the mobile phone market. Future smartphones will not only have a significant increase in processor speed, but the operating system will also become more open and intelligent, providing a better platform for software operation and content services. With the advent of the 3G communication era and the gradual maturity of IMS technology, communication efficiency and bandwidth will be greatly improved. Multi-mode access to mobile phones will become a trend, and application services based on 3G mobile phones will become more and more abundant. Multi-value-added services can be launched on this, such as commodities, weather, news, stocks, transportation, application downloads, etc., so manufacturers no longer only focus on smart phones, but more concerned about communication software and content services, so communication software and mobile Internet have Strong market potential, such as mobile TV, mobile search, mobile online games and other fields will have broad market prospects. 1. IMS, VCC and WIFI technology 1. IMS (IP Multimedia Subsystem) IMS (IP MulTImedia Subsystem) is an important part of the third-generation mobile communication core network. It is a network system based on IP technology and integrating Internet, mobile network, data, voice and video [1]. The goal of IMS is to integrate Internet and mobile communication network. Now IMS has been defined as a multimedia service core network that supports all IP access networks and can support any type of mobile or fixed, wired or wireless IP-CAN (IP ConnecTIvity Access Networks), including W-CDMA, CDMA2000 , TD-SCDMA, Ethernet, xDSL and WirelessLAN and other access methods, so as to achieve the independence of its access. The IMS core network mainly uses SIP (Session IniTIaTIon Protocol) protocol for session control. Through IMS, 3G (3rd Generation Mobile Communications System) network can provide users with PoC (Push to talk over Cellular, Push to Talk), multimedia conference, instant messaging, presence and other services. From the perspective of network architecture, IMS is a network superimposed on the original circuit domain and packet domain networks. The packet domain carries signaling and user data, and can communicate with the original circuit domain. 2. VCC (Voice Call Continuity) Wireless local area network (WLAN) technology has been greatly developed in recent years, and has been widely used in office areas, homes, communication hotspots, etc. Users can completely access the IMS core network through WLAN, thereby using IMS-based VoIP (Voiceover IP) )phone service. At the same time, the following two points should be noted: First, the voice service provided by the CS domain is a basic source of income, it is impossible to stop immediately, and it will coexist with the IMS network for a long time. Second, although IMS adopts SIP-based service implementation methods to support VoIP services, its voice quality is difficult to be guaranteed. Voice Call Continuity (Voice Call Continuity, VCC) is 3GPP's solution for continuity of voice calls between the IMS domain and the CS domain. Based on the VCC service, by introducing dual-mode or multi-mode mobile terminal devices that support GSM / CDMA / UMTS and WLAN access methods, users can access IMS via WLAN for voice calls in areas covered by WLAN. When the user moves out of WLAN After the service area, it will roam to the mobile cellular network to continue the voice call, and can seamlessly switch between the two. 3. WIFI (wireless fidelity technology) It is one of the IEEE 802.11 network specifications. The maximum bandwidth can reach 11 Mbps. According to the actual situation, the bandwidth can be automatically adjusted to three different bandwidths, namely 5.5Mbps, 2Mbps and 1Mbps. The automatic adjustment of the bandwidth effectively protects the network Stability and reliability. With "fast speed, high reliability" and other characteristics. In open areas, the communication distance can reach 305 meters, and in closed areas, the communication distance is 76 meters to 122 meters, which is convenient for integration with existing wired Ethernet networks, and the cost of networking is lower. WLAN (Wireless Local Area Network) is a wireless network composed of AP (Access Point) and wireless network card. An AP is called a network bridge or an access point. It is a bridge or link between a traditional wired local area network and a wireless local area network, so any terminal equipped with a wireless network card can share a wired local area network or a wide area network through the AP. Network resources, its working principle is equivalent to a HUB or routing with a built-in wireless transmitter, and the wireless network card is the terminal device responsible for receiving the signal transmitted by the AP. 2. Software and hardware architecture system design In order to create the software and hardware system platform of this smartphone, the system architecture needs to be designed based on the implementation principles and specific functional requirements of IMS and VCC. The following figure is a system architecture diagram based on Linux and IMS. With Yuchai Engine Diesel Generator With Yuchai Engine Diesel Generator,Yuchai Diesel Generator,Yuchai Diesel Generator Set,Yuchai Generator Shanghai Kosta Electric Co., Ltd. , https://www.shkostagenerator.com