tailieunhanh - McGraw Hill - 2002 - W-CDMA and cdma2000 for 3G Mobile Networks_9

Tham khảo tài liệu 'mcgraw hill - 2002 - w-cdma and cdma2000 for 3g mobile networks_9', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 288 Chapter 8 RANAP 6 RANAP provides signaling between a UTRAN and a core network CN and supports both connection-oriented and connectionless transfers of user data. For connection-oriented services signaling links are established or removed dynamically. RANAP is notified if any of these connections fail at any time. Some of the functions performed by RANAP are listed here Management of radio access bearers RAB RANAP provides for the establishment maintenance and release of RABs. The term RAB is used to indicate the service provided by the UTRAN when user data is to be transferred between a UE and a CN. For example it may include physical channels over the air interface logical channels for packet mode data etc. Although the overall responsibility for managing RABs and signaling connections resides with the CN an RNC may request their release at any time. Relocation of a serving RNC As an MS moves from the domain of one RNC to another or from one serving area to another the MS is to be handed over to a new RNC or another system and so radio resources must be reassigned. To maintain the continuity of service it may be necessary to establish some new signaling connections or tear down some old ones. Similarly RABs may have to be added or deleted depending upon the new location of the UE. Resetting of Iu interface RANAP may reset an Iu interface under certain conditions. Load balancing of an Iu interface RANAP provides procedures for controlling the load on an Iu interface so that it remains within its prescribed limits. Paging RANAP provides for paging a UE. Transferring non-access stratum NAS signaling messages between a CN and a UE NAS messages are those messages that are exchanged between a CN and a UE transparently to the UTRAN. In other words these messages do not terminate on the UTRAN. A signaling message may be sent to set up a new connection. On the other hand a signaling message could also be sent over an already existing connection. Call Controls and .