TAILIEUCHUNG - Scalable voip mobility intedration and deployment- P30

Scalable voip mobility intedration and deployment- P30: 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. | 290 Chapter 7 Public Switched Telephony Network PSTN Figure The Anatomy of a Cellular Call Voice over Cellular and Licensed Spectrum 291 The base station is the antenna tower and network radio itself. These are located with overlapping coverage everywhere the network needs to provide service. Usually these towers are on poles next to highways on billboards or on the sides or tops of buildings. The mobile operator leases the sites that the towers are placed and runs cables from the tower to the shed where the base station is located. The base station takes care of generating the signals that run the cell and making sure that each of the phones are properly connected to the network just as an access point does with Wi-Fi. Located in a more central area is the base station controller. The base station controller provides the intelligence behind the cell. A base station controller can have multiple base stations attached to it with dedicated digital links. The controller manages the base stations and controls the mobile phones associated to each base station. The radio behavior of each of the base stations is determined and enforced by the controller including channel assignments coding operation. The compressed audio from the telephones also terminates at the base station controller which decompresses the audio converting it into streams of PCM. The base station controller aggregates these audio lines only some of which will have phone calls active on them onto trunks and sends the calls to the centralized gateway switch. The gateway switch is the first true telephone switch and straddles the border between the public switched telephone network PSTN and the private network of the mobile operator in the area. Gateway switches usually serve a geographic region and serve the purpose of bridging the call from the wireless portion of the network directly into the standard telephone system. The gateway switch is the mobile operator s PBX not .

• 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