CDMA2000 Mobile Wireless Network Architecture CDMA2000 builds on the inherent advantages of CDMA technologies and introduces other enhancements, such as Orthogonal Frequency Division Multiplexing (OFDM and OFDMA), advanced control and signaling mechanisms, improved interference management techniques, end-to-end Quality of Service (QoS), and new antenna techniques such as Multiple Inputs Multiple Outputs (MIMO) and Space Division Multiple Access (SDMA) to increase data throughput rates and quality of service, while significantly improving network capacity and reducing delivery cost. WCDMA and CDMA2000 have the same characteristics (roaming support, same data rates, wide band, etc). The main difference between the WCDMA and CDMA2000 is that the WCDMA uses only one wide band, while CDMA2000, apart from the wide band uses several narrow bands (low data rate channels). CDMA2000 network Architecture diagram CDMA2000 is a hybrid 2.5G / 3G technology of mobile telecommunications that uses code division multiple access to send digital radio, voice, data, and signaling data between mobile phones and cell sites. CDMA2000 is standardized by the 3rd Generation Partnership Project 2 (3GPP2).
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18547969 Demonstration of Call Flow in a CDMA NetworkCPT2
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CDMA2000 Mobile Wireless Network Architecture
CDMA2000 builds on the inherent advantages of CDMA technologies and introduces
other enhancements, such as Orthogonal Frequency Division Multiplexing (OFDM
and OFDMA), advanced control and signaling mechanisms, improved interference
management techniques, end-to-end Quality of Service (QoS), and new antenna
techniques such as Multiple Inputs Multiple Outputs (MIMO) and Space Division
Multiple Access (SDMA) to increase data throughput rates and quality of service,
while significantly improving network capacity and reducing delivery cost. WCDMA
and CDMA2000 have the same characteristics (roaming support, same data rates,
wide band, etc). The main difference between the WCDMA and CDMA2000 is that
the WCDMA uses only one wide band, while CDMA2000, apart from the wide band
uses several narrow bands (low data rate channels).
CDMA2000 network Architecture diagram
CDMA2000 is a hybrid 2.5G / 3G technology of mobile telecommunications that uses
code division multiple access to send digital radio, voice, data, and signaling data
between mobile phones and cell sites. CDMA2000 is standardized by the 3rd
Generation Partnership Project 2 (3GPP2).
Figure - CDMA2000 Network Architecture in detail
THE CDMA2000 NETWORK COMPRISES OF THREE MAJOR PARTS
• Mobile station (MS)
• The Core Network (CN)
• The radio access network (RAN)
THE MOBILE STATION (MS): This is the device which terminates the radio path on the
user side of the network and enables subscribers to access network services over
the Um interface. In CDMA2000, there is no need to replace the CDMA MS in order
to function in the network; but in order to receive the full services of the CDMA2000
the MS should be replaced.
THE RADIO ACCESS NETWORK (RAN): In a CDMA2000 access network, two Radio
Access Network technologies are supported; 1xRTT and EV-DO (Evolution-Data
Optimized or Evolution-Data only). CDMA2000 is considered a 2.5G (or 2.75G)
technology when the 1xRTT access network is used and a 3G technology when
the EV-DO access network is used.
• CDMA2000 1xRTT: The core CDMA2000 wireless air interface standard is
also known as 1x, 1xRTT, and IS-2000. The designation "1x", meaning "1
times Radio Transmission Technology", indicates the same RF bandwidth as
IS-95 (CDMA-One): a duplex pair of 1.25 MHz radio channels. 1xRTT almost
doubles the capacity of IS-95 by adding 64 more traffic channels to the
forward link, orthogonal to the original set of 64. Although capable of higher
data rates, most deployments are limited to a peak of 144 Kbit/s. IS-2000
also made changes to the data link layer for the greater use of data services,
including medium and link access control protocols and QoS (Quality of
Service).
• CDMA2000 EV-DO: CDMA2000 EV-DO is a broadband access radio
technology standardized by 3rd Generation Partnership Project 2 (3GPP2),
provides access to mobile devices with air interface speeds of up to 2.4 Mbit/s
with Rev. 0 and up to 3.1 Mbit/s with Rev. A. The industry is working newer
generations of EV-DO such as Rev. B and Rev. C, etc.
Characteristics of CDMA2000 Access Network
• The CDMA2000 access network may perform mobility management functions
for registering; authorizing, authenticating and paging IP based terminals,
independent of circuit based terminals.
• The access network may perform handoffs within an access network and
between access networks of the same technology and may support handoffs
between access networks of differing technologies.
The key components of the cdma2000 access network are:
• Base Transceiver System (BTS)
• Packet Control Function (PCF)
• Base Station Controller (BSC)
Base Station Controller (BSC): an entity that provides control and management
for one or more BTSs. Apart from routing the Time division multiplexing (TDM) traffic
to the circuit switched platform, the BSC routes the packet to and from the PDSN.
Packet Control Function (PCF): an entity that provides interface function
between the access network and the packet switched core network. It is located in
the radio access network and manages the relay of packets between the BS and the
PDSN. The PCF is generally part of the BSC.
• In order to provide the feel of “always connected”, if there are packets from the
Internet to a certain MS that currently doesn’t have radio resources allocated,
the packet is held on the PCF until the user is allocated a channel. The PDSN
does not hold the packets but the PCF. The PCF may be HW and/or SW.
• The CDMA2000 may introduce firewalls to protect the network and application
servers to support packet services.
• The PDSNs, AAA and the connection to the RAN (BSCs) are via a private IP
network for security and for providing different QoS levels.
Mobile IP (not an entity)- supports moving between two different PDSNs without
needing to reconnect. It is the PDSN’s responsibility to either update the IP of the
user when they move to another PDSN area (it is implying the packet sessions need
to turn down and restart), or to implement the Mobile IP mechanism for a
transparent move. In the Mobile IP mechanism the FA and HA are required. Simple IP
(not an entity) –does not support mobility between different PDSNs. The PDSN is the
owner of the User IP (DHCP). If in the middle of a page loading the MS moves
between two different PDSNs, the MS will have to reconnect
Base Transceiver System (BTS): an entity that provides transmission capabilities
across the Um reference point. The BTS consists of radio devices, antenna and
equipment and its responsibilities include:
a) Assigning the Fundamental channel (FCHs) - the number of physical resources
available.
b) The FCH forward power (the power already allocated and available).
c) The Walsh codes required and those available.
d) SDU function: The SDU function (Selection/Distribution Unit function) includes the
following functions:
• Traffic Handler: This function exchanges traffic bits with the associated
vocoder or CDMA RLP function, and is directly connected to the A5 interface.
• Signaling Layer 2: This function performs the layer 2 functionality of the air
interface signaling protocol and is responsible for the reliable delivery of layer
3 signaling messages between the base station and the mobile station.
• Multiplex Sub-layer: This function multiplexes and demultiplexes user traffic
and signaling traffic for the air interface.
• Power Control: This function administrates the forward and reverse link
power control in a CDMA system. This function and the channel element
provide the power control function for the CDMA operation. As part of this
function, it generates or utilizes relevant power control information that is
exchanged over the air interface or with the channel element.
• Frame Selection/Distribution: This function is responsible for selecting the
“best” incoming air interface reverse link frame from the channel elements
involved in the soft handoff. It also distributes forward air interface frames to
all channel elements involved in a call.
• Backhaul Frame Handler: This function demultiplexes the control
information and the air interface reverse frame from the frame received over
the backhaul network. It also multiplexes the control information and the air
interface frames in the forward direction.
THE CORE NETWORK (CN): This is further decomposed in two parts, one interfacing
to external networks such as the Public Switched Telephone Network (PSTN)
which is called the Circuit switched domain (that based on voice) and the other
interfacing to the IP based network such as Internet, which is called the Packet