Fixed-mobile convergence (FMC) is one of the main directions in telecom development today. A vital component of this, voice call continuity (VCC), is a key network convergence service capability that will help facilitate the evolution of FMC.

VCC, a third-generation partnership project (3GPP) Internet protocol multimedia subsystem (IMS) specification, means that the service connection remains continuous and of good quality during handover when a telecom subscriber moves between different service networks.

There are many reasons why the mobile communication may be interrupted. Among them is that the mobile network may not provide thorough coverage. For example, the signal may become incomplete or even interrupted due to lack of coverage when a subscriber moves during a mobile call. The subscriber is sure to become dissatisfied with the incomplete and intermittent call. What's more, a decrease in QoS, the customer satisfaction, and even the business revenue of the operator will occur.

Then, what's the solution? As will be explained in this article, VCC is the most potent and FMC-compliant solution among all the solutions in the industry. The VCC feature allows voice service continuity through seamless and unnoticeable handoff between a cellular mobile network and a fixed wireless local-area network (WLAN).

The VCC achieves voice service continuity as a subscriber can initiate a call at any place within the cellular or Wi-Fi networks. The service will be free from interruption during handover when a subscriber moves.

Mobile communications have won rapid popularization in a very short time thanks to its many strengths, including convenience, enhanced mobile network capabilities, and enriched mobile terminal capabilities. These have brought many adverse effects on the fixed operators, including the drain of subscriber resources, the inefficient operation of network resources, and the significant decline of business revenue.

Network convergence enabled by VCC allows the fixed operators to utilize the Wi-Fi broadband access resources. The VCC provides mobile communications for fixed subscribers and mobilizes the fixed communication. In addition, the VCC helps the fixed operators to adopt some mobile communication services that have been lost because of inadequate network coverage. As a result, the fixed operators can improve the network service attractiveness and regain lost subscriber resources and business revenue.

For mobile operators, the existing frequency resources may not be adequate for a dense user area. The Wi-Fi wireless broadband access resources, not needing a license, can make up for the adverse effects on the network service capabilities due to lack of radio network resources. That is, the Wi-Fi resources can activate coverage of otherwise dead zones. Through handover between the cellular and Wi-Fi networks, the Wi-Fi resources can extend the service capabilities and service scope of the mobile operators and provide quality telecom services for mobile subscribers. The converged operators carry the features of both the fixed and the mobile networks. The VCC showcases the convergence of the fixed and the mobile services. It helps the operators enhance the converged service capabilities. VCC has many positive FMC features. Then how shall we tap its potentials? What's next for VCC?

As the most commercially promising FMC service, VCC prevents dropped mobile calls during movement between different networks. VCC facilitates convergence between the fixed and the mobile networks. However, to tap the infinite potential of the VCC, it must be deployed such that a subscriber can attain the same quality service experience using a single number, CDR, and terminal.

The V²CC is the extended VCC. It can use a single number to realize a seamless, unnoticeable, fast, and free bidirectional handover and to suit the service demands. Though mobile communication is becoming the mainstream communication mode, many subscribers are still using fixed telephones. The V²CC can help replace a mobile terminal with a fixed one. It allows the subscribers to select mobile terminals or fixed terminals according to their own custom.

Currently, voice communication is the predominant telecom service. However, as multimedia services are developing and spreading rapidly, non-voice services will certainly require seamless handover between different networks. That is a correct focus of attention for the industry. The V²CC extends the service area of the VCC. It supports not only smooth handover of the voice services but seamless bidirectional handover of the multimedia services like data and video. As V²CC is integrated with the multimedia services, it modernizes the service applications and subscriber experiences. It helps the operators accept subscriber-originated traffic, create a new commercial mode, and gain new profit space. Therefore, the mainstream telecom operators have definitely optimized service and market requirements.

The FMC is the main stream of the telecom development. The VCC plays a key role in the convergence practice. The V²CC, as the extended capability of VCC, gets integrated with many multimedia services. In this way, the V²CC will lend a great impetus to the FMC development by extending the application area and innovating continuously.