TAILIEUCHUNG - Scalable voip mobility intedration and deployment- P33

Scalable voip mobility intedration and deployment- P33: The term voice mobility can mean a number of different things to different people. Two words that can be quite trendy by themselves, but stuck together as if forgotten at a bus station long past the last ride of the night, the phrase rings a number of different, and at times discordant, bells. | 320 Chapter 7 off to the Wi-Fi network without requiring the cellular coverage to be completely diminished. The second method is to attempt to avoid Wi-Fi handoff altogether or at least to mitigate the effects. The use of channel layering wireless architectures for Wi-Fi allows the Wi-Fi network to perform the same task for its inter-access-point handoffs as the cellular network provides for its inter-base-station handoffs. By centrally controlling and regularizing the handoff process the network frees the phone to having to make only a very simple choice. Is the Wi-Fi network sufficiently strong to allow for a phone call or is the cellular network the correct network This can eliminate the problem of poor FMC call quality for mobile users in-building. Cellular-Centric Technology with UMA For voice mobility networks that may be considering a cellular-centric FMC solution the currently available technology is known as Unlicensed Mobile Access UMA . UMA integrates into the GSM cellular architecture and uses the cellular-centric FMC architecture to encode GSM signaling and bearer traffic directly over IP. UMA requires the phone to have UMA-compatible software as well as the dual-mode radio. The degree of integration of phone and handoff engines required for UMA is very high UMA interacts directly with the GSM engine and thus UMA must be installed into the cellphone by the manufacturer. Within the carrier s network the FMC mobility gateway is installed as a UMA base station controller. This controller uses what is known as the A interface to connect to the MSC or gateway switch. As far as the mobile network is concerned the entire Internet-connected phone population is local not roaming and connected to one special base station. The UMA name for the FMC mobility gateway is the UMA Network Controller UNC . As the user hands out and in from the mobile operator s network the transitions which occur appear to the GSM network as nothing more than an inter-BSC handoff. .

• Phần cứng
• lắp ráp máy tính
• sửa chữa máy tính
• sổ tay phần cứng
• MainBoard
• thiết bị máy tính
• thiết bị mạng
• Lắp ráp bảo trì máy tính
• Lắp ráp bảo trì máy tính phần 2
• Cài đặt phần mềm cho máy tính
• Bảo trì máy tính
• Cài đặt máy tính
• Phần cứng máy tính
• lỗi máy tính
• hệ thống mạch máy tính
• điện máy tính
• Tài liệu máy tính