Monday, August 24, 2009

Architecture Network of CDMA 2000


Architecture Network of CDMA 2000


Network architecture of CDMA 2000 in general can be explained as in figure below where The Radio Access Network (RAN), in CDMA2000 networks consists of multi Base Station (BS) each connected to a Radio Network Controller (RNC) or Base Station Controller (BSC). RNC manages several concurrent Radio Link protocol (RLP) layer-2 session with Mobile Node (MN) and performs per-link bandwidth management functions. The 144 kbps per carrier throughput in 3G-1x is shared among multiple active MN, though at any given instant, a single MN may be allocated full data rate. When a MN moves from one RNC to the other, the on-going RLP session is torn down and a new session is established with the visited RNC.

The Packet Data Serving Node (PDSN) in the architecture aggregates data traffic from multiple RNC and interfaces the RAN to a packet switched network. The PDSN terminates a Point-to-Point (PPP) connection and maintains session state for each mobile node (MN) in its serving area. By keeping PPP connection alive, MN will have a better quality of service.

The PDSN is required to support two modes of IP operation: Simple-IP and Mobile-IP. In Simple-IP mode, if MN moves from one PDSN to another, the PPP connection must be re-established, and new IP address is required. This requires the user to re-establish all their data sessions. In the Mobile-IP mode, the PDSN implements the Foreign Agent (FA) functionality allowing cross PDSN mobility.
















Network of CDMA2000 have components as following:
  • Mobile Station (MS)

Wireless devices above are integrated into Mobile Station (MS) or Mobile Node (MN) with primary function to conduct, maintaining and terminating the access connection (voice and data) to network. MS build connection by requesting Radio Channel to RN. After the connection was established, MS will responsible for maintaining that radio channel and buffering packets if the channel was unavailable. MS usually support for encryption and protocols such Mobile IP.

  • Radio of Network ( RN)

Consists of Base Station Transceiver Subsystem (BTS), Packet Control Function (PCF), and Base Station Controller (BSC). BTS has a function to control the MN connection within coverage area and manage data distribution to all connected MN. Primary functions of PCF are to establish, maintain and terminating a connection with Packet Data Serving Node (PDSN). PCF communicate with BSC for requesting and managing radio channel to perform packet transmission from MS and vice versa. PCF is also responsible to collect accounting information and towards it to PDSN.

  • Home Agent ( HA)

HA has a function in Mobile IP implementation by tunneling packets to Foreign Agent (FA) and vice versa. HA provides secure connection by conducted MS authentication through Mobile IP registration. HA also maintain the connection with AAA to have user profiles.

  • Authentication, Authorization And Accounting ( AAA)

AAA have different function depend on network type where it connected to if AAA server was connected to service provider network, then the primary function are overcoming request of authentication from PDSN to Home IP network, and authorize responses from Home IP network to PDSN. AAA also stores accounting information of MS and provide user profile and QoS information to PDSN. If AAA server connected to Home IP network, it conducts MS authentication and authorization as local AAA request. If AAA connected to broker network, it forward request and response between service provider network and Home IP network which not directly connected.



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