International telecommunication union
Proxies in IP-based networks
Download 496.69 Kb.
|
- Navigate this page:
- De-layering
- IP transport protocol
- Hierarchical function distribution
- Function split in control and user plane for PRM
- 1 Cellular telephone emulates the traditional wired telephone capability
3.4 Proxies in IP-based networksTo provide requirements for IP-based RAN architecture we start from the following all-IP scenario supporting reconfigurable terminals. The PRM is functionally split into a user and control plane servers following the methodology of the IP-based RAN. The IP-based RAN architecture is based on the following paradigms. De-layeringIt means that the logical and physical separation of the network elements on three functional planes: • Control plane • User plane • Transport plane The user-plane handles the user data exchanged between the terminal and the CN. Its main task is to transform the user data into radio frames to be transmitted by the radio base station and vice versa. Due to the real time radio processing requirements, the user plane functions will be implemented by a highly-specialized hardware platform: The user plane server (UPS). The control-plane manages the radio resources and controls the radio processing in the user plane. The control plane functions are grouped within the radio control server (RCS) that is typically a standard all-purpose platform. One implication is that the control functions (in the c-plane) have the capability to manage and control the radio resource in the u-plane even if they are related to different radio technologies. IP transport protocolAll traffic transport in the whole network is based on IP datagrams. Thus, the network provides end to-end IP-based connectivity and supports virtually all IP-based services. Radio base stations (BS, NodeB) are directly connected to the IP transport network. It means that the radio base stations are connected with the rest of the network via IP transport protocol. Hierarchical function distributionHierarchical distribution of the functions means that network functional entities that execute functions related to a particular access technology are grouped into functional domains called “access networks” (IPbRAN). Functions common to all access technologies are provided by the subnetwork called “core network” (IPbCN). The function split in c-plane and u-plane domain introduces scalability and load balancing for the proxies and their processing capability. Following the same approach the PRM is split into software download and reconfiguration controller (SDRC) that collects c-plane functions, and software download and profile repository (SPRE) that collects u-plane functions. Their functions, with the aim to address software download and reconfiguration functions, are explained in the following sub-chapters. For example, a new evolution of BTS could be used to interface with SDR terminal. This kind of BTS should have an IP interface and contains some of the functionality previously held in the core network with the aim to provide multimode capabilities. Figure 25 IP-based network and proxies supporting reconfigurable terminals Function split in control and user plane for PRMIt follows from Proxy functions, that the PRM is mainly involved in mode monitoring, mode negotiation, mode switching and software download, where information about user, terminal and services and control capability are required. Following the de-layering approach PRM functions can be split in u-plane and c-plane functionality. The u-plane functions collect all the profiles and the information needed for the performing of the software download. The c-plane functions collect all the functions needed to perform the control operations. We call: • SPRE: Software download and profile repository (u-plane) the logical entity that collects: • Terminal, user, service profile • Software modules • SDRC: Software download and reconfiguration controller (c-plane) the logical entity that hosts the PRM controlling functions, in particular: • Software download control functions • Reconfiguration control functions Figure 26
Collects software download and reconfiguration management functions The u-plane PRM (SPRE) should be located in the RAN, because the following information has to be available and updated as fast as possible: • Channel and system load conditions • User service profiles • Application QoS • Network address and protocol Depending from the type of coupling between different RATs and the time constraints of the service and the necessity or not to perform a seamless handover, the c-plane PRM (SDRC) could be located both in the RAN (near or included in the RNC) or in the core network (near or included in the SGSN). When the SPRE and SDRC are located both in the access network, the interaction with the RRM is more direct and the micro mobility management could be managed from a dedicated SDRC function. The following figures show the location of the SPRE and SDRC in both scenarios. FIGURE 27
High data rate packet nodes (HDRPN) 1 Cellular telephone emulates the traditional wired telephone capabilityThe intent of the cellular radio concept has, in the past, been to emulate as closely as possible the service that is provided to the user by a standard wired telephone. This was necessary to make it so the telephone user could use the cell phone just like a normal telephone and the telephone network would be useable to the providers of the cell phone service for long-distance interconnection. This made the cell phone much easier to sell, particularly in the initial stages. Using the telephone network to provide the long-distance element of the cellular service meant the primary task was to emulate the local access part of the telephone network. Technically this was not such a difficult task, but to provide low cost spectrally efficient solutions became a challenge. A solution that reassigned the expensive base station equipment and the spectrum on a call-by-call basis proved to be successful for telephone type voice traffic Directory: dms pub -> itu-r -> oth oth -> Section 1a vocabulary, characteristics and general technologies for land mobile service oth -> U. S. Mobile eas for atsc mobile dtv itu-r -> Report itu-r sa. 2312-0 (09/2014) itu-r -> Report itu-r itu-r -> 3rd itu inter-regional workshop on wrc-15 preparation geneva, 1 – 3 September 2015 oth -> Radiocommunication Study Groups oth -> Itu-r workshop on Emergency Broadcasting Speakers Biographies Lynn Claudy oth -> Coordination and notification procedures introduction Download 496.69 Kb. Share with your friends:
|
