CDMA Interface
8.1.1
Descriptions of inter-entity interfaces
Interface between MSC and BSS (A-interface)
In fact, it is the interface between MSC and BSC. Adopting 2Mb/s
PCM digital link, the standard protocols for this interface include IS-634,
IOS2.4, IOS4.0 etc.
A-interface is mainly used to transmit the following information:
1. BSS management information,
2. Call processing, and
3. Mobility management information.
Interface between MSC and VLR (B-interface)
This interface is an internal interface, without standard
definition. Its functions are as follows:
VLR is the location and management database for subscribers that
have roamed into related MSC area. When the MSC needs the subscriber data of
the particular MSC area, the MSC is to inquire the VLR; in the case of mobile
station location updating, the MSC will request VLR to store the related
information; when the user activates the supplementary services or modifies
data, the MSC will request the HLR (through VLR) to store the related data.
This interface has no standard definition, and generally uses an
internal interface.
Interface between MSC and HLR (C-interface)
Interface between the MSC and the HLR.
The system adopts the IS-41E protocol. This interface is based on
2Mb/s digital interface or 64Kb/s interface, with its interface electrical
performance conforming to GF002-9002.1 The
General Technical Specifications for Telephone Switching Equipment of the
Ministry of Posts and Telecommunications Volume 1 Digital SPC Switching Equipment General Technical Specifications
Chapter 7 and GB7611-87 Pulse Coding
Modulation Communication System Network Digital Interface Parameters; As
for the signaling specifications, for detailed description of MAP, refer to Technical Requirements for 800MHz CDMA
Digital Cellular Mobile Communication Network Mobile Application Part (MAP);
for detailed description of SCCP, refer to GF010-95 Technical Requirements for National No.7 Signaling Mode Technical
Specifications Signaling Connection Control Part (SCCP); for detailed
description of MTP, refer to GF001-9001 China
Telephone Network No.7 Signaling Mode Technical Specifications.
C-interface adopts 24-bit No.7 signaling mode.
Interface between VLR and HLR (D-interface)
The system adopts the IS-41E protocol. This interface is based on
2Mb/s digital interface or 64Kb/s interface , with its interface electrical
performance conforming to GF002-9002.1 The
General Technical Specifications for Telephone Switching Equipment of the
Ministry of Posts and Telecommunications Volume 1 Digital SPC Switching Equipment General Technical Specifications
Chapter 7 and GB7611-87 Pulse Coding
Modulation Communication System Network Digital Interface Parameters; As
for the signaling specifications, for detailed description of MAP, refer to Technical Requirements for 800MHz CDMA
Digital Cellular Mobile Communication Network Mobile Application Part (MAP);
for detailed description of SCCP, refer to GF010-95 Technical Requirements for National No.7 Signaling Mode Technical
Specifications Signaling Connection Control Part (SCCP); for detailed
description of MTP, refer to GF001-9001 China
Telephone Network No.7 Signaling Mode Technical Specifications.
D-interface uses 24-bit No.7 signaling mode.
This interface is used for switching of subscriber location
information, authorization information and service data. The major service
function of a mobile station is: it must have the capability of initiating and
receiving calls within the service area. In order to support this capability,
the HLR has to perform data switching. The VLR notifies the HLR about the
subscriber location information, and provides the subscriber roaming number.
The HLR sends the subscriber service data required by the VLR. The switching
data usually occurs when a subscriber requests for a special service, or when a
subscriber or network operator modifies the subscriber data.
Interface between MSC and MSC (E-interface)
The system adopts the IS-41E protocol. This interface is based on
2Mb/s digital interface or 64Kb/s interface, with its interface electrical
performance conforming to GF002-9002.1 The
General Technical Specifications for Telephone Switching Equipment of the
Ministry of Posts and Telecommunications Volume 1 Digital SPC Switching Equipment General Technical Specifications
Chapter 7 and GB7611-87 Pulse Coding
Modulation Communication System Network Digital Interface Parameters; as
for the signaling specifications, for detailed description of MAP, refer to Technical Requirements for 800MHz CDMA
Digital Cellular Mobile Communication Network Mobile Application Part (MAP);
for detailed description of SCCP, refer to GF010-95 Technical Requirements for National No.7 Signaling Mode Technical
Specifications Signaling Connection Control Part (SCCP); for detailed
description of MTP, refer to GF001-9001 China
Telephone Network No.7 Signaling Mode Technical Specifications.; the ISUP
part is still to be defined.
E-interface adopts the 24bit No.7 signaling mode. Its functions
are as follows:
When a mobile station roams from one MSC to another, the MSC will
perform handoff in order to keep the subscribers’ conversation uninterrupted.
In this case data switching must be implemented between the MSCs.
Interface between MSC and EIR (F-interface)
This interface has no standard definition. Its functions are as
follows:
When the mobile station is in communication, and the MSC
authenticates the mobile station, it has to inquire the EIR, so as to determine
whether the mobile station is legal, and thus deciding whether to provide
services to this mobile station.
Interface between HLR and AUC (H-interface)
Currently an internal interface is used. Its functions are as follows:
When the HLR receives an authentication request from an MS, the
HLR gets data from the AUC. When the AUC initiates the authentication
instruction to the MS, the AUC transfers the authentication information to the
subscriber via the HLR.
Interface between MC and SME and MC (M-interface)
Current the SMPP phase III standard is used. The interface’s
function is as follows:
When the short message center performs information interaction
with the short message entity and another short message center, this protocol
must be abided by.
Interface between HLR and MC (N-interface)
The interface standard is ANSI-41E. Its function is as follows:
When the short message center sends a short message to a
subscriber, if the called subscriber’s address information is not available, it
has to inquire the HLR for the subscriber’s route before it can send the short
message to the subscriber.
Interface
between MC and MSC (Q-interface)
The interface standard is ANSI-41E. Its function is as follows:
During the submission and reception of a short message, short
message transfer needs to be conducted between the short message center and
mobile switching center. At the same time, when the subscriber’s short message
capability changes, the mobile switching center needs to notify the short
message center in time.
Interface
between MSC and OMC
This interface conforms to the network requirements of TMN, and
provides standard Q3 interface to the upper-level TMN.
Interfaces
with PSTN/ISDN (Ai/Di Interfaces)
The CDMA digital cellular mobile network inter-works with
PSTN/ISDN through the mobile switching center (MSC) and provides voice, data
and certain supplementary services for subscribers. Its interfaces are
2048kb/s-based digital interfaces. TUP and ISUP of the SS7 signaling are
adopted with priority as the interface signaling specifications. Where
conditions are not available, China No.1 signaling can be used.
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