Cellular data communication protocol

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The protocols described here are from different cellular data communication protocols.

Base Station Management Application Part (BSMAP)[edit]

TIA/EIA/IS-634-A, revision A

The Base Station Management Application Part (BSMAP) supports all Radio Resource Management and Facility Management procedures between the MSC and the BS, or to a cell(s) within the BS. BSMAP messages are not passed to the MS, but are used only to perform functions at the MSC or the BS. A BSMAP message (complete layer 3 information) is also used together with a DTAP message to establish a connection for an MS between the BS and the MSC, in response to the first layer 3 interface message sent by the MS to the BS for each MS system requests.

BSSLAP[edit]

http://webapp.etsi.org/key/queryform.asp 3GPP TS 08.71

BSSLAP defines the SMLC-BSS layer 3 protocol . The following Location Services related messages are exchanged between the SMLC and the BSS, with the VMSC acting as a relay.

On the A interface the messages are contained in the Location Information IE which is encapsulated in the BSSMAP-LE Connection Oriented Information message as specified in 3GPP TS 08.08. On the Ls interface the messages are contained in the Location Information IE which is encapsulated in the BSSMAP-LE Connection Oriented Information message as specified in 3GPP TS 09.31.

The following messages types are available:

Message Encoding
Reserved 00000000
TA Request 00000001
TA Response 00000010
TOA Request 00000100
TOA Response 00000101
Reject 00001010
Reset 00001011
Abort 00001100
TA LAYER3 00001101
MS Position Command 00001111
MS Position Response 00010000

BSSAP[edit]

GSM 08.06 http://www.etsi.fr

The MTP and the SCCP are used to support signalling messages between the Mobile Services Switching Center (MSC) and the Base Station System (BSS). One user function of the SCCP, called BSS Application Part (BSSAP) is defined. In the case of point-to-point calls the BSSAP uses one signalling connection per active mobile station having one or more active transactions for the transfer of layer 3 messages. In the case of a voice group or broadcast call there is always one connection per cell involved in the call and one additional connection per BSS for the transmission of layer 3 messages. There is an additional connection for the speaker in a broadcast call or the first speaker in a voice group call up to the point at which the network decides to transfer them to a common channel. Additional connections may also be required for any mobile stations in the voice group or broadcast call which the network decides to place on a dedicated connection. The BSSAP user function is further subdivided into two separate functions:

The Direct Transfer Application sub-Part (DTAP), also called GSM L3, is used to transfer messages between the MSC and the MS (Mobile Station); the layer-3 information in these messages is not interpreted by the BSS. The descriptions of the layer 3 protocols for the MS-MSC information exchange are contained in the 04- series of GSM Technical Specifications. The BSS Management Application sub-Part (BSSMAP) supports other procedures between the MSC and the BSS related to the MS (resource management, handover control), or to a cell within the BSS, or to the whole BSS. The description of the layer 3 protocol for the BSSMAP information exchange is contained in Recommendation GSM 08.08. Both connectionless and connection-oriented procedures are used to support the BSSMAP. Rec. GSM 08.08 explains whether connection oriented or connectionless services should be used for each layer 3 procedure. Connection oriented procedures are used to support the DTAP. A distribution function located in BSSAP, which is reflected in the protocol specification by the layer 3 header, performs the discrimination between the data related to those two subparts.

Discrimination Distribution between the two sub-protocols: BSSMAP and DTAP.

DLCI[edit]

Only for DTAP. Used in MSC to BSS messages to indicate the type of origination data link connection over the radio interface.

Length Subsequent Layer3 message parameter length.

BSSAPLE[edit]

http://webapp.etsi.org/key/queryform.asp. 3GPP TS 09.31 and 3GPP TS 04.71

BSSAP-LE is an extension to BSSAP that contains messages and parameters specific to the support of LCS. The BSSAP-LE is part of the LB interface. The following subsets of BSSAP-LE are defined: DTAP-LE and BSSMAP-LE. DTAP-LE messages are transferred between an SMLC and a Type A LMU. BSSMAP-LE messages are transferred between a BSC, MSC and SMLC.

The following BSSMAP-LE message types are available:

Code Message
0X2B Perform Location Request
0X2D Perform Location Response
0X2E Perform Location Abort
0X1 LMU Connection Request
0X2 LMU Connection Accept
0X3 LMU Connection Reject
0X4 LMU Connection Release
0X2A Connection Oriented Information
0X3A Connectionless Information
0X30 Reset
0X31 Reset Acknowledge

BSSMAP[edit]

GSM 08.08 http://www.etsi.fr

The BSS Management Application Part (BSSMAP) supports all of the procedures between the MSC and the BSS that require interpretation and processing of information related to single calls, and resource management. Some of the BSSMAP procedures result in, or are triggered by, Radio Resource (RR) management messages defined in GSM 04.08.

Message Type A one octet field defining the message type. This mandatory field uniquely defines the function and format of each BSSMAP message.

Information Element Each IE has an identifier which is coded as a single octet. The length of an IE may be fixed or variable and may or may not include a length indicator.

BTSM[edit]

GSM 08.58 http://www.etsi.fr

BTSM is the Base Station Controller to Base Transceiver Station (BSC - BTS) interface protocol (the A-bis interface). BTSM allows sending messages between the Base Station Controller and the Base Transceiver Station. Protocol messages consist of a series of information elements. For each message there are mandatory information elements and optional information elements. BTSM messages are transmitted on the A-bis interface using the I format of LAPD, except for the Measurement Result message which is sent in UI format.

Message discriminator 1-octet field used in all messages to discriminate between Transparent and Non-Transparent messages and also between Radio Link Layer Management, Dedicated Channel Management, Common Channel Management and TRX Management messages.

Message type Uniquely identifies the function of the message being sent. It is a single octet field.

CC[edit]

GSM 04.08 http://www.etsi.fr

The call control (CC) protocol is one of the protocols of the Connection Management (CM) sublayer. Every mobile station must support the call control protocol. If a mobile station does not support any bearer capability at all then it must respond to a SETUP message with a RELEASE COMPLETE message. In the call control protocol, more than one CC entity are defined. Each CC entity is independent from each other and communicates with the correspondent peer entity using its own MM connection. Different CC entities use different transaction identifiers.

Certain sequences of actions of the two peer entities compose elementary procedures. These elementary procedures may be grouped into the following classes:

  • Call establishment procedures.
  • Call clearing procedures.
  • Call information phase procedures.
  • Miscellaneous procedures.

The terms "mobile originating" or "mobile originated" (MO) are used to describe a call initiated by the mobile station. The terms "mobile terminating" or "mobile terminated" (MT) are used to describe a call initiated by the network.

Protocol discriminator[edit]

0011 identifies the CC protocol.

TI flag[edit]

Identifies who allocated the TI value for this transaction. The purpose of the TI flag is to resolve simultaneous attempts to allocate the same TI value.

TI value[edit]

TI values are assigned by the side of the interface initiating a transaction. At the beginning of a transaction, a free TI value is chosen and assigned to this transaction. It then remains fixed for the lifetime of the transaction. After a transaction ends, the associated TI value is free and may be reassigned to a later transaction. Two identical transaction identifier values may be used when each value pertains to a transaction originated at opposite ends of the interface.

Message type[edit]

CC message types may be as follows. Bit 8 is reserved for possible future use as an extension bit. Bit 7 is reserved for the send sequence number in messages sent from the mobile station.

0x000000 Escape to nationally specific message types
0x00 Call establishment messages:
0001 ALERTING
1000 CALL CONFIRMED
0010 CALL PROCEEDING
0111 CONNECT
1111 CONNECT ACKNOWLEDGE
1110 EMERGENCY SETUP
0011 PROGRESS
0101 SETUP
0x01 Call information phase messages:
0111 MODIFY
1111 MODIFY COMPLETE
0011 MODIFY REJECT
0000 USER INFORMATION
1000 HOLD
1001 HOLD ACKNOWLEDGE
1010 HOLD REJECT
1100 RETRIEVE
1101 RETRIEVE ACKNOWLEDGE
1110 RETRIEVE REJECT
0x10 Call clearing messages:
0101 DISCONNECT
1101 RELEASE
1010 RELEASE COMPLETE
0x11 Miscellaneous messages:
1001 CONGESTION CONTROL
1110 NOTIFY
1101 STATUS
0100 STATUS ENQUIRY
0101 START DTMF
0001 STOP DTMF
0010 STOP DTMF ACKNOWLEDGE
0110 START DTMF ACKNOWLEDGE
0111 START DTMF REJECT
1010 FACILITY

DTAP (CDMA)[edit]

TIA/EIA/IS-634-A, revision A

The Direct Transfer Application Part (DTAP) messages are used to transfer call processing and mobility management messages to and from the MS. The BS does not use DTAP messages, but must map messages going to and coming from the MSC into the appropriate air interface signaling protocol. Transaction IDs are used to associate the DTAP messages with a particular MS and the current call. The format of the header is shown in the following illustration:

Protocol discriminator[edit]

The protocol discriminator specifies the message being transferred (CC, MM, RR). Transaction identifier Distinguishes multiple parallel activities (transactions) within one mobile station. The format of the transaction identifier is as follows:

TI flag[edit]

Identifies who allocated the TI value for this transaction. The purpose of the TI flag is to resolve simultaneous attempts to allocate the same TI value.

TI value[edit]

TI values are assigned by the side of the interface initiating a transaction. At the beginning of a transaction, a free TI value is chosen and assigned to this transaction. It then remains fixed for the lifetime of the transaction. After a transaction ends, the associated TI value is free and may be reassigned to a later transaction. Two identical transaction identifier values may be used when each value pertains to a transaction originated at opposite ends of the interface.

Message Type[edit]

The message type defines the function of each DTAP message.

Information elements[edit]

Each information element has a name which is coded as a single octet. The length of an information element may be fixed or variable and a length indicator for each one may be included.

DTAP (GSM)[edit]

GSM 04.08, 08.06, 08.08 http://www.etsi.fr

The Direct Transfer Application Part (DTAP) are used to transfer call control and mobility management messages between the MSC and the MS. The DTAP information in these messages is not interpreted by the BSS. Messages received from the MS are identified as DTAP by the Protocol Discriminator Information Element. The majority of radio interface messages are transferred across the BSS MSC interface by DTAP, except for messages belonging to the Radio Resource (RR) management protocol.

The DTAP function is in charge of transferring layer 3 messages from the MS (or from the MSC) to the MSC (or to the MS) without any analysis of the message contents. The interworking between the layer 2 protocol on the radio side and signalling system 7 at the landside is based on the use of individual SCCP connections for each MS and on the distribution function.

Protocol discriminator[edit]

Identifies the L3 protocol to which the standard layer 3 message belongs. Values may be as follows:

0000 Group call control
0001 Broadcast call control
0010 PDSS1
0011 Call control; call related SS messages
0100 PDSS2
0101 Mobility Management Messages
0110 Radio resources management messages
1001 SMS messages
1011 Non-call related SS messages
1110 Extension of the PD to one octet length
1111 Tests procedures described in TS GSM 11.10

Transaction ID / Skip identifier[edit]

Either a transaction identifier, or a skip indicator depending on the level 3 protocol. The transaction identifier contains the transaction value and flag which identifies who allocated the TI.

N(SD)[edit]

For MM and CM, N(SD) is set to the value of the send state variable. In other level 3 messages, bit 7 is set to 0 by the sending side. Messages received with bit 7 set to 1 are ignored.

Message type[edit]

Uniquely defines the function and format of each GSM L3 message. The message type is mandatory for all messages. The meaning of the message type is therefore dependent on the protocol (the same value may have different meanings in different protocols) and direction (the same value may have different meanings in the same protocol, when sent from the Mobile Station to the network and when sent from the network to the Mobile Station).

Information elements[edit]

The message type may be followed by various information elements depending on the protocol.

MM[edit]

GSM 04.08 http://www.etsi.fr

The main function of the Mobility Management (MM) sub-layer is to support the mobility of user terminals, such as informing the network of its present location and providing user identity confidentiality. A further function of the MM sub-layer is to provide connection management services to the different entities of the upper Connection Management (CM) sub-layer

Protocol discriminator[edit]

0101 identifies the MM protocol.

Message type[edit]

MM message types may be as follows. Bit 8 is reserved for possible future use as an extension bit. Bit 7 is reserved for the send sequence number in messages sent from the mobile station.

0x00 Registration messages:
0001 IMSI DETACH INDICATION
0010 LOCATION UPDATING ACCEPT
0100 LOCATION UPDATING REJECT
1000 LOCATION UPDATING REQUEST
0x01 Security messages:
0001 AUTHENTICATION REJECT
0010 AUTHENTICATION REQUEST
0100 AUTHENTICATION RESPONSE
1000 IDENTITY REQUEST
1001 IDENTITY RESPONSE
1010 TMSI REALLOCATION COMMAND
1011 TMSI REALLOCATION COMPLETE
0x10 Connection management messages:
0001 CM SERVICE ACCEPT
0010 CM SERVICE REJECT
0011 CM SERVICE ABORT
0100 CM SERVICE REQUEST
1000 CM REESTABLISHMENT REQUEST
1001 ABORT
0x11 Miscellaneous messages:
0001 MM STATUS

MMS[edit]

http://www.openmobilealliance.org/ OMA-MMS-ENC-v1_1-20021030-C.

The WAP Multimedia Messaging Service (MMS) uses WAP WSP/HTTP as underlying protocols to transfer MMS PDUs between the MMS Client, which resides on the terminal (MS) and the MMS Proxy -Relay.

This structure is based on the well-known message structure of Internet email binary encoding of MMS PDUs. Because of the limited bandwidth of the air interface of mobile networks MMS PDUs are transferred between an MMS Client and an MMS Proxy -Relay in binary encoded message format. This process is called encapsulation. WSP PDUs or HTTP messages, which contain MMS PDUs as their body, are used for this transport.

MMS PDUs, which are described in this specification, are included in WSP PDUs/HTTP messages of different types. The entire MMS information is contained in MMS PDUs, which are encapsulated in WSP PDUs/HTTP messages.

The content type of WSP PDUs/HTTP messages containing MMS PDUs is "application/vnd.wap.mms - message."

MMS has no header structure as it consists of messages.

Field Reference Number:
0x81 Bcc
0x82 Cc
0x83 X-Mms-Content-Location
0x84 Content-Type
0x85 Date
0x86 X-Mms-Delivery-Report
0x87 X-Mms-Delivery-Time
0x88 X-Mms-Expiry
0x89 From
0x8A X-mms-Message-Class
0x8B Message-ID
0x8C X-Mms-Message-Type
0x8D X-Mms-MMS-Version
0x8E X-Mms-Message-Size
0x8F X-Mms-Priority
0x90 X-Mms-Read-Report
0x91 X-Mms-Report-Allowed
0x92 X-Mms-Response-Status
0x93 X-Mms-Response-Text
0x94 X-Mms-Sender-Visibility
0x95 X-Mms-Status
0x96 Subject
0x97 To
0x98 X-Mms-Transaction-Id
0x99 X-Mms-Retrieve-Status
0x9A X-Mms-Retrieve-Text
0x9B X-Mms-Read-Status
0x9C X-Mms-Reply-Charging
0x9D X-Mms-Reply-Charging-Deadline
0x9E X-Mms-Reply-Charging-ID
0x9F X-Mms-Reply-Charging-Size
0xA0 X-Mms-Previously-Sent-By
0xA1 X-Mms-Previously-Sent-Date

Message Type[edit]

The following message types are contained in the PDU:

128 m-send-req
129 m-send-conf
130 m-notification-ind
131 m-notifyresp-ind
132 m-retrieve-conf
133 m-acknowledge-ind
134 m-delivery-ind
135 m-read-rec-ind
136 m-read-orig-ind
137 m-forward-req
138 m-forward-conf

RR[edit]

GSM 04.08 http://www.etsi.fr

RR (Radio Resource) management procedures include the functions related to the management of the common transmission resources, e.g., the physical channels and the data link connections on control channels. The general purpose of Radio Resource procedures is to establish, maintain and release RR connections that allow a point-to-point dialogue between the network and a Mobile Station. This includes the cell selection/reselection and the handover procedures. Moreover, Radio Resource management procedures include the reception of the uni-directional BCCH and CCCH when no RR connection is established. This permits automatic cell selection/reselection.

Protocol discriminator[edit]

0110 identifies the RR Management protocol.

Skip identifier[edit]

Value of 0000.

Message type[edit]

Uniquely defines the function and format of each RR message. The message type is mandatory for all messages. RR message types may be:

00111- - - Channel establishment messages:
011 ADDITIONAL ASSIGNMENT
111 IMMEDIATE ASSIGNMENT
001 IMMEDIATE ASSIGNMENT EXTENDED
010 IMMEDIATE ASSIGNMENT REJECT
00110- - - Ciphering messages:
101 CIPHERING MODE COMMAND
010 CIPHERING MODE COMPLETE
00101- - - Handover messages:
110 ASSIGNMENT COMMAND
001 ASSIGNMENT COMPLETE
111 ASSIGNMENT FAILURE
011 HANDOVER COMMAND
100 HANDOVER COMPLETE
000 HANDOVER FAILURE
101 PHYSICAL INFORMATION
00001- - - Channel release messages:
101 CHANNEL RELEASE
010 PARTIAL RELEASE
111 PARTIAL RELEASE COMPLETE
00100- - - Paging messages:
001 PAGING REQUEST TYPE 1
010 PAGING REQUEST TYPE 2
100 PAGING REQUEST TYPE 3
111 PAGING RESPONSE
00011- - - System information messages:
000 SYSTEM INFORMATION TYPE 8
001 SYSTEM INFORMATION TYPE 1
010 SYSTEM INFORMATION TYPE 2
011 SYSTEM INFORMATION TYPE 3
100 SYSTEM INFORMATION TYPE 4
101 SYSTEM INFORMATION TYPE 5
110 SYSTEM INFORMATION TYPE 6
111 SYSTEM INFORMATION TYPE 7
00000- - - System information messages:
010 SYSTEM INFORMATION TYPE 2bis
011 SYSTEM INFORMATION TYPE 2ter
101 SYSTEM INFORMATION TYPE 5bis
110 SYSTEM INFORMATION TYPE 5ter
00010- - - Miscellaneous messages:
000 CHANNEL MODE MODIFY
010 RR STATUS
111 CHANNEL MODE MODIFY ACKNOWLEDGE
100 FREQUENCY REDEFINITION
101 MEASUREMENT REPORT
110 CLASSMARK CHANGE
011 CLASSMARK ENQUIRY

See also[edit]