BTS-BSC Inter-operability (A bis Interface)

Transcription

1 BTS-BSC Inter-operability (Abis Interface) A.S000-Av.0 GPP A.S000-A Version.0 Date: July 00 0 BTS-BSC Inter-operability (A bis Interface) (Post SDO Ballot, Pre-SDO Publication) 0 GPP 00 GPP and its Organizational Partners claim copyright in this document and individual Organizational Partners may copyright and issue documents or standards publications in individual Organizational Partner's name based on this document. Requests for reproduction of this document should be directed to the GPP Secretariat at secretariat@gpp.org. Requests to reproduce individual Organizational Partner's documents should be directed to that Organizational Partner. See for more information.

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3 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Table of Contents. Introduction.... Objectives.... Scope of the document.... References..... Telecommunications Industry Association (TIA) / Electronics Industry Association (EIA)..... Standards Committee T..... International Telecommunications Union - Telecommunications Sector (ITU-T)..... Other.... Terminology.... Acronyms.... Others.... Network Reference Model and Interfaces.... Support of user traffic connections to a frame selector function.... Support of paging channel messaging.... Support of Access channel messaging Support of broadcast system information functions Layers & Physical Layer Specification (Layer ) Use of ATM (Layer ) Field of Application ATM Layer..... ATM Adaptation Layer..... Network and Transport Protocols.... Call Processing.... Mobile Originating Call..... Abis-ACH Message Transfer..... Unused Section..... Abis-BTS Setup..... Abis-Connect..... Abis-Connect Ack..... Abis-BTS Setup Ack..... Abis-IS-000 FCH Forward..... Abis-IS-000 FCH Reverse..... Abis-PCH Msg Transfer Abis-PCH Msg Transfer Ack Abis-Traffic Channel Status Successful Mobile Originating Call.... Mobile Terminated Call..... Abis-PCH Message Transfer..... Abis-PCH Message Transfer Ack..... Abis-BTS Setup..... Abis-Connect... i

4 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Abis-Connect Ack..... Abis-BTS Setup Ack..... Abis-IS-000 FCH Forward..... Abis-IS-000 FCH Reverse..... Abis-ACH Message Transfer Unused section..... Abis-Traffic Channel Status..... Successful Mobile Terminated Call.... Call Clearing..... Call Clearing initiated by MS..... Call Clearing initiated by BS/MSC..... Call Clearing initiated by BTS..... Call Clearing initiated by MS..... Call Clearing initiated by BSC/MSC..... Call Clearing initiated by BTS.... Handoff..... Abis-BTS Interface Procedures and Messages..... Soft/Softer Handoff addition (Intra-BTS)..... Soft/Softer Handoff addition (Inter-BTS)..... Soft/Softer Handoff Removal (Inter-BTS)..... Hard Handoff (Inter-BTS) SMS Delivery..... SMS Delivery on the Paging channel..... Call flow example for SMS Delivery on the Paging channel..... SMS Delivery on the Access channel..... SMS Delivery on the Traffic channel to MS SMS Delivery on the Traffic channel from MS.... Traffic Burst Operation..... Abis-Burst Request..... Abis-Burst Response..... Abis-Burst Commit..... High Speed Packet Data..... Initial Traffic Burst Example Abis Connection Not Yet Established..... Subsequent Traffic Burst Example.... PACA Service PACA Updating Call flow example for PACA Updating.... Abis Interface Message.... Abis Interface Message Formats..... Message Body, Coding, and Ordering of Elements..... Message Processing Guidelines..... Message Definition Guidelines.... Abis interface messages... ii

5 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Abis-ACH Msg Transfer..... UNUSED SECTION..... Abis-PCH Msg Transfer..... Abis-PCH Msg Transfer Ack..... Abis-BTS Setup..... Abis-BTS Setup Ack Abis-BTS Release Abis-BTS Release Ack Abis-Burst Request Abis-Burst Response..... Abis-Burst Commit..... Abis-Connect..... Abis-Connect Ack..... Abis-Remove..... Abis-Remove Ack..... Abis-IS-000 FCH Fwd..... Abis-IS-000 FCH Rvs..... Abis-Traffic Channel Status..... Abis-BTS Release Request Abis-IS-000 SCH Fwd..... Abis-IS-000 SCH Rvs..... Abis-IS-000 DCCH Fwd..... Abis-IS-000 DCCH Rvs..... Abis-PACA Update.... Information Element Definitions.... Information Element Identifiers.... Message Type.... Correlation ID.... Mobile Identity.... Cell Identifier.... Air Interface Message.... UNUSED SECTION.... Layer Ack Request/Results.... Cause....0 Call Connection Reference.... Band Class.... Privacy Info.... Cell Identifier List.... SDU ID.... Physical Channel Info.... Cell Information Record.... Service Option.... PACA Timestamp... iii

6 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Quality of Service Parameters....0 Abis Connect Information.... Abis Originating ID.... Abis Destination ID.... Downlink Radio Environment.... CDMA Serving One Way Delay.... Forward Burst Radio Info.... Reverse Burst Radio Info.... IS-000 Forward Power Control Mode.... IS-000 FPC Gain Ratio Info.... BTS L Termination....0 CDMA Target One Way Delay.... Walsh Code Assignment Reqest.... PACA Order.... Authentication Challenge Parameter (RAND) Abis Ack Notify.... Timer Definitions.... Tconnb :Timer for Abis-Connect message.... Tsetupb : Timer for Abis-BTS Setup message.... Tchanstatb : Timer for Abis-Traffic Channel Status message.... Tdisconb : Timer for Abis-Remove Ack message.... Tdrptgtb : Timer for Abis-BTS Release Ack message.... Tbstreqb : Timer for Abis-Burst Response message.... Tbstcomb : Timer for Abis-BTS Release Ack message.... Trelreqb : Timer for Abis-BTS Release message... iv

7 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Table of Figures FIGURE - REFERENCE MODEL... FIGURE - RELATIONSHIP BETWEEN AIR INTERFACE AND ABIS INTERFACE (INTRA-BS MODEL)... FIGURE...- DELIMITING MESSAGES IN AN ABIS APPLICATION TCP BYTE STREAM... FIGURE..- MOBILE ORIGINATING CALL... FIGURE..- MOBILE TERMINATED CALL... FIGURE..- CALL CLEARING INITIATED BY MS... FIGURE..- CALL CLEARING INITIATED BY BSC/MSC... FIGURE..- CALL CLEARING INITIATED BY BTS... FIGURE..- SOFT/SOFTER HANDOFF ADDITION (INTRA-BTS)... FIGURE..- SOFT/SOFTER HANDOFF ADDITION (INTER-BTS)... FIGURE..- SOFT/SOFTER HANDOFF REMOVAL (INTER-BTS)... FIGURE..- HARD HANDOFF (INTER-BTS)...0 FIGURE..- SMS DELIVERY ON THE PAGING CHANNEL... FIGURE...- SMS DELIVERY ON THE ACCESS CHANNEL... FIGURE..- SMS DELIVERY ON THE TRAFFIC CHANNEL TO MS...0 FIGURE..- SMS DELIVERY ON THE TRAFFIC CHANNEL FROM MS... FIGURE..- INITIAL TRAFFIC BURST EXAMPLE... FIGURE..- SUBSEQUENT TRAFFIC BURST EXAMPLE... FIGURE..- PACA UPDATING PROCEDURE... Table of Tables TABLE - LAYER TERMINATION TYPE... TABLE - ABIS INTERFACE DESCRIPTION... TABLE..- ELEMENT FLOW DIRECTION INDICATION... TABLE.- ABIS INFORMATION ELEMENT IDENTIFIERS SORTED BY IDENTIFIER VALUE... TABLE.- ABIS MESSAGE TYPE VALUES... TABLE - TIMER VALUES AND RANGE... v

8 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Introduction This document is the specification for the Abis interface (between the Base Transceiver System (BTS) and Base Station Controller (BSC) for IS-000 system. The signaling flows and these signals are described.. Objectives The Abis interface specification provides an open and inter-operable system.. Scope of the document This specification defines the interface between BTS and BSC within the BS. The interface between BSs is specified in the TIA/EIA/IS-00. Following features are not specified in this version of the specification. They are for further study. Operations, Administration, Maintenance, and Provisioning (OAM&P)* Abis Overload control SMS-Broadcast Inter BSC hard/soft handoff * Flood paging * It is recommended that any OAM&P related information be aligned with the TIA/EIA-, Abis interface.. * Inter BSC (BS) hard/soft handoff is supported in the TIA/EIA/IS-00. The functions supported in TIA/EIA/IS-00 shall be supported implicitly for the Abis interface and shall not modify the information transmitted on the radio channels. The conditions for supporting Abis Interface features are equivalent to TIA/EIA/IS-00.. References 0

9 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Telecommunications Industry Association (TIA) / Electronics Industry Association (EIA) TIA/EIA/IS-00; Inter-operability Specification (IOS) for CDMA 000 Access Network Interfaces (also referenced as GPP TSG-A s A.S000); December, 000. TIA/EIA/IS-B; Mobile Station - Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Systems; March,.. Standards Committee T ANSI T. -, B-ISDN - ATM Layer Functionality and Specification,... International Telecommunications Union - Telecommunications Sector (ITU-T).. Other ITU-T Recommendation I.., B-ISDN ATM Adaptation layer specification: Type AAL; September,. ITU-T Recommendation I.., B-ISDN ATM Adaptation Layer specification: Type AAL; August,. ITU-T Recommendation I..; Segmentation and Reassembly Service Specific Convergence Sublayer for the AAL type ; June,. ITU-T Recommendation Q., Broadband-Integrated Services Digital Network (B-ISDN) Digital Subscriber Signalling No. (DSS) User-Network Interface Layer Specification for Basic Call/Connection Control,. Internet Engineering Task Force, RFC - Internet Protocol (IP),. Internet Engineering Task Force, RFC - Transmission Control Protocol (TCP),.

10 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Terminology. Acronyms The following is a list of acronyms that are used in this specification text. AAL ATM Adaptation Layer type AAL ATM Adaptation Layer type ADDS Application Data Delivery Service ANSI American National Standards Institute ARFCN Absolute Radio Frequency Channel Number ATM Asynchromous Transfer Mode BSC Base Station Controller BSMAP Base Station Management Application Part BTS Base Transceiver System CC Conference Calling CCITT International Telegraph and Telephone Consultative Committee (See ITU) CDMA Code Division Multiple Access CID Circuit IDentifier (used with reference to AAL) CM Connection Management cudp compressed IP/UDP FCH Fundamental Channel IETF Internet Engineering Task Force IMSI International Mobile Subscriber Identity IOS Interoperability Specification IP Internet Protocol ISDN Integrated Services Digital Network ISLP Intersystem Link Protocol ITU International Telecommunications Union kb kilo bits LAC Location Area Code LSB Least Significant Bit MAC Medium Access Control MIN Mobile Identification Number MS Mobile Station MSB Most Significant Bit MSC Mobile Switching Center OAM&P Operations, Administration, Maintenance, and Provisioning OTD Orthogonal Transmit Diversity PACA Priority Access and Channel Assignment

11 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) 0 0 PATE Packet Arrival Time Error PCF Packet Control Function PCM Pulse Code Modulation PN Pilot Number PPP Point to Point Protocol PSPDN Packet Switched Public Data Network PSTN Public Switched Telephone Network QoS Quality of Service RAND Random Variable RFC Request for Comment RLP Radio Link Protocol SCH Supplemental Channel SCM Service Connect Message SCTP Stream Control Transmission Protocol SDU Selection/Distribution Unit function SMS Short Message Service SMS-MO SMS Mobile Originated SMS-MT SMS Mobile Terminated SSCS Service Specific Convergence Sublayer SSD Shared Secret Data SSSAR Service Specific Segmentation and Reassembly TCP Transmission Control Protocol UDP User Datagram Protocol. Others ) In this document the term cell is used to refer to a sector with in a cell. ) The messages indicated with solid lines flow over the Abis interface and the messages indicated with dashed lines flow over interfaces other than the Abis interface.

12 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Network Reference Model and Interfaces Figure - shows the network reference model that is referred to in this specification. a) Abis interface = Abis signaling + Abis traffic b) A Selection Distribution Unit (SDU) function is located in the BSC c) A channel element is located in the BTS Notes: The handoff procedure between BTSs within a BSC is defined in this document. The handoff procedure between the BSs has been defined in TIA/EIA/IS-00. Figure - Reference Model There are architecture for the L terminations were considered. They are shown in the following Table -. L B S Abis Signaling BTS BSC Abis Traffic CH element SDU Function Abis Signaling Abis Traffic L r-csch(*) f-csch(*) Type A Type B L L L Authentication BSC ARQ ARQ LAC Addressing Addressing BSC Utility Utility SAR SAR BTS MAC MAC MAC L L L BTS Table - Layer termination type BTS CH element Abis Interface (*) r-csch (reverse common signaling logical channel) This logical channel is applied for the case that MS sends message on the ACH and BTS replies on the PCH. In r-csch, LAC sub-layer is composed by Authentication sub-layer, ARQ sub-layer, Addressing sub-layer, Utility

13 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) 0 sub-layer and SAR sub-layer. (*) f-csch (forward common signaling logical channel) This logical channel is applied for the case that BTS sends message on the PCH and MS replies on the ACH. In f-csch, LAC sub-layer is composed ARQ sub-layer, Addressing sub-layer, Utility sub-layer and SAR sub-layer. In this specification type A is introduced as architecture for initial phase. However we are also introducing type B for the next release. In this release of the Abis specification L termination is mandatory to be supported by the BTS. To allow for a migration to new architectures, a mechanism is provided on the Abis interface whereby the BTS can specify if L termination function will be supported. If the BTS indicates that it does not support L termination, then the BSC shall support L termination. In this release of the Abis specification the BTS shall specify to the BSC that it terminates L termination.

14 BTS-BSC Inter-operability (Abis Interface) A.S000-Av.0 Figure - shows the relationship between logical air interface channels and Abis interface signal Air Interface Abis Interface BS MS BTS Abis traffic BSC FCH (f/r-dsch, f/r-dtch) FCH (Abis-IS-000 FCH Fwd/Rvs) SCH (f/r-dtch) SCH (Abis-IS-000 SCH Fwd/Rvs) DCCH (f/r-dsch, f/r-dtch) DCCH (Abis-IS-000 DCCH Fwd/Rvs) Abis Signaling ACH (r-csch) PCH (f-csch) ACH (Abis-ACH Msg Transfer) PCH (Abis-PCH Msg Transfer) Abis Signaling OAM Signaling (FFS) Note:This figure is informative. In this figure, some signals defined in the air interface are omitted for clarity. Figure - Relationship between Air interface and Abis interface (Intra-BS Model)

15 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Table - summaries the details of the Abis interface Table - Abis interface description Abis function Transaction Abis Message (A/A message related to Abis) Abis connection establish (BSC invoke) - call setup - Handoff - Abis-BTS Setup - Abis-BTS Setup Ack - Abis-Connect (A-HO Req.) (A-HO Req. Ack) (A-Connect) Abis connection release (BSC invoke) Abis connection release (BTS invoke) - call release - Handoff - Abis-Connect Ack - Abis-BTS Release - Abis-BTS Release Ack - Abis-Remove - Abis-Remove Ack - Abis-BTS Release Request - Abis-BTS Release - Abis-BTS Release Ack - Abis-Remove - Abis-Remove Ack (A-Connect Ack) (A-Drop) (A-Drop Ack) (A-Remove) (A-Remove Ack) (A-Tgt rm. req.) (A-Drop) (A-Drop Ack) (A-Remove) (A-Remove Ack) PCH transfer - Abis-PCH Msg Transfer - Abis-PCH Msg Transfer Ack ACH transfer - Abis-ACH Msg Transfer (A-ACH...) SCH transfer - SCH setup - Abis-Burst Request and establish - Abis-Burst Response -Abis-Burst Commit (A-PCH...) (A-PCH... Ack) (A-Burst Req.) (A-Burst Rsp.) (A-Burst Commit) 0. Support of user traffic connections to a frame selector function In a CDMA system, the user traffic (voice, data, etc.) of a Mobile Station (MS) may be connected to the network using one or more connections from MS to BTS(s). If multiple connections are used for a single flow of user information, the user traffic connection is said to be in soft handoff. The first step within the network is to carry these multiple connections back to a single point from which a selection is made of the best frame received over the radio connections. This implies a connection from each involved BTS back to a central point where frame selection occurs. This central point is referred to as the SDU function. 0. Support of paging channel messaging When an MS is to be sent a message on a paging channel, the BSC typically formats the majority of the message and forwards it to the BTS along with various parameters including the destined cell identifier. The ability to forward such a paging message from the BSC to the BTS is part of the functionality of the Abis interface. An additional requirement of a CDMA system is that such a message may also need to be forwarded between BSCs to be transmitted on a BTS belonging to a BSC other than the

16 BTS-BSC Inter-operability (Abis Interface) A.S000-Av BSC that originally created the message. This requirement comes through support for access handoff and other such IS- and IS-000 features. The BSC to BSC signaling interface to support such forwarding has been defined in the TIA/EIA/IS-00.. Support of Access channel messaging When an MS sends a message on an access channel, the BTS will forward that message to the BSC along with various parameters including the identity of the cell and sector on which the message was received, etc. The ability to forward such an access message from BTS to the BSC is part of the functionality of the Abis interface. An additional requirement of a CDMA system is that such a message may also need to be forwarded between BSCs (i.e., to a BSC other than the one that owns the BTS that originally received the message). This requirement comes through support for access handoff and other such IS- and IS-000 features. The BSC to BSC signaling interface to support such forwarding has been defined in the TIA/EIA/IS-00.. Support of broadcast system information functions In a IS- or a IS-000 system, each BTS broadcasts various pieces of system information that the MS captures and uses during its interactions with the network. Much of that system information may be administrated through OAM&P functions. A small amount of such system information may be placed in BTS and OAM&P control of a BTS for the same purposes.. Layers & 0.. Physical Layer Specification (Layer ) The physical layer specification is flexible to deploy the various new technologies. Vendors shall have flexibility in providing the latest technology. And operators shall have flexibility in choosing from various options, including T, E, 0/00 base T, OC, OC, etc... Use of ATM (Layer ) Asynchronous Transfer Mode (ATM) is a suite of protocols that allow fast, efficient delivery of user traffic in a packet environment. ATM, for the purposes of this standard, consists of two main layers: the ATM Layer that uses the physical layer, and the ATM Adaptation Layer that adapts the basic ATM layer to specific usage... Field of Application Asynchronous Transfer Mode (ATM) is used to transport both signaling and user traffic (voice/data). 0

17 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) ATM Layer The ATM Layer uses a basic -octet cell consisting of a -octet header and -octet payload. This standard uses the ATM Layer as specified in ANSI T.- Telecommunications Broadband ISDN - ATM Layer Functionality and Specification without modification. For this specification only ATM permanent virtual circuits (PVC s) shall be required for the Abis interface. These virtual circuits shall be configured through administrative procedures and no special signaling interface procedures, e.g., ATM UNI (Q.), shall be required... ATM Adaptation Layer To make use of the basic cell transfer capability of the ATM Transport Layer in specific uses, various ATM Adaptation Layers (AALs) have been defined. Within this standard, two AALs are used: AAL - for the transfer of signaling, and AAL - for the transfer of user traffic (voice/data) on Abis traffic sub-channels. Both AAL and AAL are used without modification in this standard. The Service Specific Segmentation and Re-assembly (SSSAR) sub-layer for AAL, as specified in ITU-T I.., is used for segmentation and re-assembly of AAL SDUs. In this version of this standard, the functionality of other sub-layers of AAL is not supported. Specifically, Service Specific Transmission Error Detection (SSTED) and Service Specific Assured Data Transfer (SSADT) are not included... Network and Transport Protocols... Signaling Connection Transport Protocol Options IOS Application TCP Signaling over the Abis interface requires a reliable transport protocol and appropriate addressing and routing mechanisms to deliver messages from source to destination. The Abis signaling application is independent of the underlying transport, which is left to the discretion of operators and manufacturers. The signaling protocol stack options available to operators and manufacturers for the Abis interface include: Abis Interface (signaling connection): IOS Application TCP IOS Application UDP IOS Application SCTP AAL is described in ITU-T I.., B-ISDN ATM Adaptation Layer Specification: Type AAL, August. AAL is described in ITU-T Recommendation I.., B-ISDN ATM Adaptation Layer Type Specification, September.

18 BTS-BSC Inter-operability (Abis Interface) A.S000-Av.0 IP AAL IP Link Layer IP Link Layer IP Link Layer 0 0 ATM Phys. Lyr. Phys. Lyr. (Note ) Phys. Lyr. (Note ) Phys. Lyr. (Note ) It is mandatory for operators and manufacturers to support ATM based link layer for signaling over the Abis interface. The other signaling connection may support any of the protocol stacks above and is left to the discretion of operators and vendors. UDP may be used and limited to those cases when reliable delivery is not required : e.g., case when BSC sends general page message. (Note ) These protocol stacks shown in the table are examples.... User Traffic Connection Transport Protocol Options The protocol stack options for transport of user traffic that are available to operators and manufacturers include: Abis Interface (user traffic sub-channel): Abis Traffic SSSAR AAL ATM Phys. Layer Abis Traffic UDP IP Link Layer Phys. Layer (Note ) Abis Traffic cudp SSCS AAL ATM Phys. Layer (Note ) Abis Traffic cudp PPPmux Link Layer Phys. Layer (Note ) It is mandatory for operators and manufacturers to support ATM based transport for user traffic over the Abis interface. The other signaling connection may support any of the protocol stacks above and is left to the discretion of operators and vendors. (Note ) These protocol stacks shown in the table are examples.... TCP Transport Protocol Usage The standard TCP, as described in RFC, shall be used for establishing, using, and clearing TCP connections.... General Use of TCP TCP connections for signaling may be set up on a per-call basis or signaling messages for multiple calls may be multiplexed on a single TCP connection. The TCP provides a reliable byte stream transfer. Therefore, a means needs to be provided for two application entities to delimit the messages sent between them. The technique for such delimitation is as follows.

19 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) 0... Message Delimiting in TCP TCP provides a reliable byte stream between two application entities. Because the protocol in this standard uses messages to communicate, these messages shall be delimited in the TCP byte stream. Such delimitation shall be done by means of a two-byte flag field and a two-byte length field inserted at the beginning of each message sent over a TCP connection. The flag field shall contain the hex value F. The purpose of the flag field is to facilitate verification of message boundaries and fast reestablishment of synchronization if synchronization of message boundaries is lost. See Figure...-:

20 BTS-BSC Inter-operability (Abis Interface) A.S000-Av.0 0 Flag 0 0 Flag Length (MSB) Length (LSB) First Octet of Abis Application Message Second Octet of Abis Application Message Msg Third Octet of Abis Application Message... Last Octet of Abis Application Message Flag 0 0 Flag Length (MSB) Length (LSB) First Octet of Abis Application Message Second Octet of Abis Application Message Msg Third Octet of Abis Application Message... Last Octet of Abis Application Message Flag 0 0 Flag Length (MSB) Length (LSB) First Octet of Abis Application Message Second Octet of Abis Application Message Msg Third Octet of Abis Application Message... Figure...- Delimiting Messages in an Abis Application TCP Byte Stream... TCP Connection Establishment A new TCP connection is established when a signaling message related to a call has to be exchanged over an interface, and no such connection exists over the particular interface. Normal TCP connection establishment procedures are used.

21 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) 0... TCP Connection Release An existing TCP connection over an interface is released when there are no more signaling messages to be exchanged over the interface. Normal TCP connection release procedures are used.... TCP Port Usage The following TCP port values are reserved for signaling across Abis interfaces: Abis: 0 -- This is the well-known TCP port at a BS used for Abis signaling interconnection between BTSs and a BSC.... Use of TCP for the Abis Interface The standard "Transport Control Protocol (TCP)", as described in RFC and shown in TIA/EIA/IS-00 section IP Network Protocol Usage The standard IP protocol, as defined in RFC (see TIA/EIA/IS-00 section..), shall be used for routing Internet Protocol packets.

22 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Call Processing. Mobile Originating Call The following subsections describe the procedure for establishing a call through a mobile originating action. Mobile originating call setup involves exchange of the following BSC-BTS messages: Abis-ACH Msg Transfer Abis-BTS Setup Abis-Connect Abis-Connect Ack Abis-BTS Setup Ack Abis-IS-000 FCH Fwd Abis-IS-000 FCH Rvs Abis-PCH Msg Transfer Abis-PCH Msg Transfer Ack Abis-Traffic Channel Status.. Abis-ACH Message Transfer The Abis-Access Channel(ACH) Message Transfer is sent by the BTS to the BSC to notify the BSC of the reception of an access channel message.... Successful Operation When the BTS receives an access channel message, it shall encapsulate that message in the Abis-ACH Msg Transfer, forward it to the BSC. The BTS may be responsible for sending the Data Burst message for such forwarded access channel message. Please refer to section.., Abis-ACH Msg Transfer, for the format and content of this message.... Failure Operation None.

23 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface).. Unused Section Abis-BTS Setup The Abis-BTS Setup message is used by the BSC to request that the BTS allocate resources in one or more cells for support of a call association.... Successful Operation When the BSC decides that one or more cells at the BTS are needed to support one or more physical channel connections for a call, the BSC sends an Abis-BTS Setup message to the BTS to indicate the resources required. The BSC then starts timer Tsetupb. Please refer to section.., Abis-BTS Setup, for the format and content of this message.... Failure Operation If timer Tsetupb expires, the BSC may choose to resend the Abis-BTS Setup message... Abis-Connect The Abis-Connect message is sent from the BTS to the BSC to initiate to one or more Abis traffic connection. The Abis-Connect Ack message is expected in response.... Successful Operation Upon receiving the Abis Signaling Address information, the BTS begins the process of establishing the Abis signaling connection with the BSC. The Abis Signaling Address is used by the BTS to allocate a logical circuit to be used for Abis signaling. The SDU ID identifies the particular instance of the SDU function. Following the establishment of the Abis signaling link, the Abis-Connect message is sent from the BTS to the BSC. The BTS expects an Abis-Connect Ack message indicating the result of processing the Abis-Connect message and starts timer Tconnb. When the Abis traffic connection(s) is established, traffic packets are exchanged to verify that the two entities can communicate via the Abis traffic connection(s). Please refer to section.., Abis-Connect, for the format and content of this message.... Failure Operation If timer Tconnb expires, the BTS may choose to resend the Abis-Connect message... Abis-Connect Ack The Abis-Connect Ack message is sent from the BSC to the BTS to indicate the result of processing the Abis-Connect message.

24 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Successful Operation After processing the Abis-Connect message from the BTS, the BSC will indicate success/failure to the BTS by sending an Abis-Connect Ack message. If the Abis-Connect Ack message indicates that Abis-Traffic Channel Status message are to be sent, then the BSC starts timer Tchanstatb to await Abis-Traffic Channel Status message(s) for all new cells on each Abis connection. One instance of this timer is started for each Abis connection to which one or more cells are being added. Please refer to section.., Abis-Connect Ack, for the format and content of this message.... Failure Operation If an instance of timer Tchanstatb expires, the BSC may assume that a failure has occurred at the BTS during activation of the transmitter(s)/receiver(s) and delete the unreported cells from the active set attached to the Abis connection. The BSC may then send an Abis-BTS Release message to the BTS to cleanly remove those cells from the Abis connection... Abis-BTS Setup Ack The Abis-BTS Setup Ack message is used by the BTS to respond to a request that it allocates resources in one or more cells for support of one or more physical channel connections for a call association.... Successful Operation When the BTS receives an Abis-BTS Setup message, it determines what internal resources are needed to support the requested physical channels for the call association. Once those resources are allocated and the Abis-Connect Ack message(s) has been received, the BTS responds by sending an Abis-BTS Setup Ack message to the BSC. Please refer to section.., Abis-BTS Setup Ack, for the format and content of this message.... Failure Operation None... Abis-IS-000 FCH Forward This message is sent from the BSC to the BTS on the Abis traffic subchannel connection of type IS-000 FCH (TIA/EIA/IS-000 Fundamental Channel). It contains the Forward air-frame for the served MS along with control information for the BTS.... Successful Operation This message is sent from the BSC to the BTS on Abis traffic subchannel connections of type FCH (Fundamental Channel). FCH messages are sent once every 0ms.

25 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Please refer to section.., Abis-IS-000 FCH Fwd, for the format and content of this message.... Failure Operation None... Abis-IS-000 FCH Reverse This message is sent from the BTS to the BSC on Abis traffic subchannel connections of type IS-000 FCH (TIA/EIA/IS-000 Fundamental Channel). It contains the decoded Reverse Traffic Channel frame received from the served MS along with control information.... Successful Operation This message is sent to the BSC on the Abis traffic subchannel connections of type IS-000 FCH (TIA/EIA/IS-00 Fundamental Channel) following the decoding of the Reverse Traffic Channel frame. IS-000 frames are sent once every 0ms. Please refer to section.., Abis-IS-000 FCH Rvs, for the format and content of this message.... Failure Operation None... Abis-PCH Msg Transfer The Abis-Paging Channel (PCH) Msg Transfer is sent by the BSC to request that a particular message is sent on the specified paging channel(s).... Successful Operation When the BSC wishes to send a message to the mobile station on the paging channel(s) of the BTS, it encapsulates that message in an Abis-(PCH) Msg Transfer and sends it to the BTS. A Layer acknowledgment indication can be requested. If such an acknowledgment is received from the MS, an Abis-Paging Channel Message Transfer ACK message is used to convey that information back to the BSC Please refer to section.., Abis-PCH Msg Transfer for the format and content of this message.... Failure Operation None.

26 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Abis-PCH Msg Transfer Ack The Abis-PCH Msg Transfer Ack is used to respond to a request for a Layer acknowledgment included in an Abis-PCH Msg Transfer...0. Successful Operation When the BTS receives the Abis-PCH Msg Transfer including Abis Ack Notify IE, the BTS sends the Abis-PCH Msg Transfer Ack upon receipt of the Layer acknowledgment. Please refer to section.., Abis-PCH Msg Transfer Ack for the format and content of this message...0. Failure Operation None... Abis-Traffic Channel Status The Abis-Traffic Channel Status message is used by the BTS to notify the BSC that radio transmission on the forward link has begun for the indicated cells, and that the corresponding receivers have been activated. This message is sent when the Abis-Connect Ack message indicates that it is requested.... Successful Operation When the BTS needs to notify the BSC of a status change relative to a specific set of cells on one Abis connection, it sends an Abis-Traffic Channel Status message. This message can be used to note that the indicated set of cells has begun radio transmission on the forward link and that the corresponding receivers have been activated. When this message is used in response to an Abis-Connect Ack message, the BTS does not need to send this message if the transmitters(s)/receiver(s) are not turned on at the BTS (i.e., the radio transmission on the forward link has not begun for the indicated cells). Multiple instances of this message may be sent relative to a single Abis connection if, for instance, transmitter(s)/receiver(s) are activated at different times; however, all cells referenced within a single instance of this message shall be attached to the same Abis connection. The BSC stops the instance of timer Tchanstatb for that Abis connection when Abis-Traffic Channel Status message(s) have been received containing references to all cells added to the Abis connection by the Abis-Connect message. Please refer to section.., Abis-Traffic Channel Status, for the format and content of this message.... Failure Operation None. 0

27 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface).. Successful Mobile Originating Call This section describes the call flow associated with an MS call origination in the IS-000 system. BS MS BTS BSC MSC Time Comment Origination BS Ack Order Tconnb Null Traffic Extended Channel Assignment Traffic Channel Preamble BS Ack Order Idle Tch Data Frames MS Ack Order Abis-ACH Msg. Transfer (ORM) Abis-PCH Msg Transfer (BS Ack Order) Complete L Info: CM Service Req. T0 Assignment Request Abis-BTS Setup Abis-Connect Tsetupb Abis-Connect Ack Abis-BTS Setup Ack Abis-IS-000 FCH Fwd (Null Data) Abis-IS-000 FCH Rvs (Idle) Abis-PCH Msg. Transfer (ECAM) T0 Abis-IS-000 FCH Rvs (T-CH Preamble) Abis-IS-000 FCH Fwd (BS Ack Order) Abis-IS-000 FCH Rvs (Idle) Abis-IS-000 FCH Rvs (MS Ack Order) a b c d e f g h i j k l m n o Service Connect Abis-IS-000 FCH Fwd (SCM) p Service Connect Completion Abis-IS-000 FCH Rvs (SCCM) q Assignment Complete r Figure..- Mobile Originating Call 0 a. The MS transmits an Origination Message, with layer acknowledgement required, over the access channel of the air interface to the BTS. Then the BTS sends an Abis-ACH Msg Transfer including the Origination message frame in Abis signaling interface.

28 BTS-BSC Inter-operability (Abis Interface) A.S000-Av b. The BTS may acknowledge the receipt of the Origination Message with a Base Station Acknowledgment Order to the MS, or will send this Base Station Acknowledgment Order to the MS encapsulated in the Abis-Paging Channel Message Transfer from the BSC. c. The BSC constructs the CM Service Request message, places it in the Complete Layer Information message, and sends the message to the MSC and starts timer T0. If the BSC requested a preferred terrestrial circuit in the CM Service Request message and the MSC can support that terrestrial circuit, the MSC shall use the same terrestrial circuit in the Assignment Request message. Otherwise, the MSC may assign a different terrestrial circuit. d. The MSC sends an Assignment Request message to the BSC to request assignment of radio resources. This message will include information on the terrestrial circuit, if one is to be used between the MSC and the BSC. The MSC then starts timer T0. Upon the receipt of the Assignment Request message, the BSC stops timer T0. e. The BSC sends an Abis-BTS Setup message to the BTS to request allocation of radio resource at the BTS. The BSC starts timer Tsetupb. This step can occur any time after receipt of the Origination message from the BTS. f. If resources are available, the BTS responds with an Abis-Connect message. The BTS starts timer Tconnb. g. The BSC sends Abis-Connect Ack message to the BTS. The BTS stops timer Tconnb. h. The BTS sends Abis-BTS Setup Ack to the BSC to acknowledge the Abis-BTS Setup. If the BSC requested a preferred Walsh code in the Abis-BTS Setup message and the BTS can support this Walsh code assignment then the BTS includes this same Walsh code in the Abis-BTS Setup Ack message. Otherwise the BTS may allocate a different Walsh code assignment. The BSC stops timer Tsetupb. i. The BSC transmits the Abis-IS-000 FCH Fwd message including Null Data to let the BTS send Null traffic data toward the MS. Then the BTS begin sending Null Traffic data for synchronizing between the BTS and the MS. The BTS may have a function that enables to send a Null Traffic data for synchronization between the BTS and the MS. BSC can notify whether the BTS has the function or not by sending Null Traffic.

29 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) j. The BTS sends Abis-IS-000 FCH Rvs message including Idle data to the BSC. k. The BSC sends an Abis-PCH Msg Transfer including Extended Channel Assignment message to the BTS. The BTS sends an Extended Channel Assignment message to the MS over the paging channel of the radio interface (with the MS address) to initiate the establishment of a radio traffic channel. l. The MS begins sending the traffic channel preamble (TCH Preamble) to the BTS over the designated reverse traffic channel. Then the BTS transmits this preamble with an Abis-IS-000 FCH Rvs message. m. Once the BSC acquires the reverse traffic channel, it sends an Abis-IS-000 FCH Fwd message including a Base Station Acknowledgement Order with layer acknowledgement required, to the MS over the forward traffic channel. n. After receiving a BS Ack Order message, the MS begins sending Idle TCH Data Frames over the reverse traffic channel. Then the BTS transmits this frame message with an Abis-IS-000 FCH Rvs message. o. The MS Ack Order message is sent from the MS, and then the BTS transmits it to the BSC with an Abis-IS-000 FCH Rvs message. p. The BSC then sends the Abis-IS-000 FCH Fwd message including the Service Connect message to the BTS specifying the service configuration for the call. Then the BTS transmits the Service Connect message to the MS. The MS begins processing traffic in accordance with the specified service configuration. q. On receipt of the Service Connect message, the MS responds with a Service Connect Completion message. Then the BTS transmits it with an Abis-IS-000 FCH Rvs message. r. After the radio traffic channel and circuit have both been established and fully interconnected, the BSC sends the Assignment Complete message to the MSC and considers the call to be in conversation state. The MSC stops timer T0 upon receipt of the Assignment Complete message.

30 BTS-BSC Inter-operability (Abis Interface) A.S000-Av.0

31 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Mobile Terminated Call The following subsections describe the procedure for establishing a call through a mobile terminated action. Mobile terminated call setup involves exchange of the following BSC-BTS messages: Abis-PCH Message Transfer Abis-PCH Message Transfer Ack Abis-BTS Setup Abis-Connect Abis-Connect Ack Abis-BTS Setup Ack Abis-IS-000 FCH Fwd Abis-IS-000 FCH Rvs Abis-ACH Message Transfer Abis-ACH Message Transfer Ack Abis-Traffic Channel Status.. Abis-PCH Message Transfer See section..... Abis-PCH Message Transfer Ack See section Abis-BTS Setup See section..... Abis-Connect See section..... Abis-Connect Ack See section...

32 BTS-BSC Inter-operability (Abis Interface) A.S000-Av.0.. Abis-BTS Setup Ack See section..... Abis-IS-000 FCH Forward See section..... Abis-IS-000 FCH Reverse See section Abis-ACH Message Transfer See section Unused section.. Abis-Traffic Channel Status See section...

33 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface).. Successful Mobile Terminated Call This section describes the call flow associated with a mobile station call termination in the IS-000 system. MS BTS BSC MSC Time Comment General Page Page Response BS Ack Order Null Traffic Extended Channel Assignment TCH Preamble BS Ack Order Idle Tch Data Frames MS Ack Order Service Connect Serv. Con. Completion Alert with Info MS Ack Order Connect Order BS Ack Order Tconnb Abis-PCH Msg. Transfer (GPM) Abis-ACH Msg. Transfer (PRM) Abis-BTS Setup Abis-Connect Abis-Connect Ack Abis-BTS Setup Ack Abis-IS-000 FCH Fwd (Null Data) Abis-IS-000 FCH Rvs (Idle) Abis-PCH Msg. Transfer (ECAM) Abis-IS-000 FCH Rvs (Preamble) Abis-IS-000 FCH Fwd (BS Ack) Abis-IS-000 FCH Rvs (Idle) Abis-IS-000 FCH Rvs (MS Ack) Abis-IS-000 FCH Fwd (SCM) Abis-IS-000 FCH Rvs (SCCM) Abis-IS-000 FCH Fwd (AWIM) Abis-IS-000 FCH Rvs (MS Ack) Abis-IS-000 FCH Rvs (Connect Order) Abis-IS-000 FCH Fwd (BS Ack) Paging Request Complete L Info: Paging Response T0 Assignment Request Tsetupb Assignment Complete Connect T0 T0 a b c d e f g h i j k l m n o p q r s t u v w x y Figure..- Mobile Terminated Call

34 BTS-BSC Inter-operability (Abis Interface) A.S000-Av a. The MSC sends the Paging Request message to the BSC to initiate a mobile terminated call setup scenario. b. The BSC constructs a General Page Message (GPM), places the message into an Abis-PCH Msg Transfer Message and sends the Abis-PCH Msg Transfer Message to the BTS. The BTS sends the GPM to the MS over the paging channel. The BSC may send this message to multiple BTSs managed by this BSC. In the following description, it is assumed that the BSC sends this message to single BTS. c. The MS acknowledges the page by transmitting a Page Response Message (PRM) to the BTS over the access channel. Upon receipt of this message, the BTS places this message into an Abis-ACH Msg Transfer Message and sends it to the BSC. d. The BTS acknowledges the receipt of the PRM from the MS by sending a Base Station Acknowledgement Order to the MS. e. The BSC sends the Complete Layer Information message containing the Paging Response message to the MSC. The BSC starts timer T0. The BSC may request the MSC to allocate a preferred terrestrial circuit. f. The MSC sends an Assignment Request message to request assignment of radio resources. The message will also include terrestrial circuit if one it to be used between the MSC and the BSC. The MSC then starts timer T0. If the BSC requested a preferred terrestrial circuit in the CM Service Request message and the MSC can support that terrestrial circuit, the MSC shall use the same terrestrial circuit in the Assignment Request message. Otherwise the MSC may assign a different terrestrial circuit. Upon receipt of the Assignment Request message from the MSC, the BSC stops timer T0. g. The BSC sends an Abis-BTS Setup message to the BTS to request allocation of radio resources at the BTS. The BSC may allocate a code channel and include it in the Abis-BTS Setup. The BSC starts timer Tsetupb. h. Upon receipt of Abis-BTS Setup message, the BTS allocates radio resources and sends Abis-Connect message to initiates an Abis

35 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) connection and to report the result of resource allocation. The BTS starts timer Tconnb. i. The BSC replies with an Abis-Connect Ack message to complete the Abis connection. The BTS stops timer Tconnb. j. The BTS sends Abis-BTS Setup Ack to acknowledge the Abis-BTS Setup. If the BSC requested a preferred Walsh code in the Abis-BTS Setup message and the BTS can support this Walsh code assignment then the BTS includes this same Walsh code in the Abis-BTS Setup Ack message. Otherwise the BTS may allocate a different Walsh code assignment. The BSC stops timer Tsetupb. k. The BSC sends an Abis-IS-000 FCH Fwd (Null Traffic Data) message to the BTS. The BTS starts sending Null Traffic Data to the mobile station. This allows the mobile station to acquire the FCH (Fundamental channel). The BTS may have a function that enables to send a Null Traffic data for synchronization between the BTS and the MS. BSC can notify whether the BTS has the function or not by sending Null Traffic.. l. Upon receiving the first Abis-IS-000 FCH Fwd (Null Traffic Data) message, the BTS starts to send Abis-IS-000 FCH Rvs (Idle frame) message to the BSC. m. The BSC sends an Extended Channel Assignment message to assign the FCH. n. The MS starts to send the Traffic Channel Preamble. Upon receiving the Traffic Channel Preamble, the BTS stops sending the idle frames and starts sending the traffic frames containing the Traffic Channel Preamble. o. The BSC sends the BS Ack Order to the MS via the BTS in the Abis-IS-000 FCH Fwd message. p. The MS stops transmitting the Traffic Channel Preamble and starts to transmit idle traffic channel data frames upon receipt of the BS Ack order. q. The MS sends the MS Ack Order to acknowledge the BS Ack order. This is sent by the BTS to the BSC in the Abis-IS-000 FCH Rvs message.

36 BTS-BSC Inter-operability (Abis Interface) A.S000-Av r. The BSC sends the Service Connect Message (SCM) to the MS specifying the service configuration for the call. This message is sent by the BSC to the BTS in the Abis-IS-000 FCH Fwd message. The MS begins processing traffic in accordance with the specified service configuration. s. Upon receipt of the Service Connect Message (SCM), the MS responds with a Service Connect Completion Message (SCCM). Upon receipt of this message, BTS sends an Abis-IS-000 FCH Rvs message containing this message to the BSC. t. After the radio traffic channel and circuit have both been established, the BSC sends the Assignment Complete message to the MSC. The MSC stops timer T0 upon the receipt of the Assignment Complete message from the BSC and starts timer T0. u. The BSC sends Alert with Information Message (AWIM) to the MS to cause ringing at the MS. This message is sent by the BSC to BTS in the Abis-IS-000 FCH Fwd message. v. The MS acknowledges the reception of the Alert with Information Message by transmitting the MS Ack Order. w. When the call is answered at the MS, a Connect Order, with acknowledgment required, is transmitted to the BSC via the BTS. x. The BSC acknowledges the Connect Order with the BS Ack order. y. The BSC sends a Connect message to the MSC to indicate that the call has been answered at the MS. At this point, the call is considered stable and in the conversation state. The MSC stops timer T0 upon receipt of the Connect message from the BSC. 0

37 A.S000-Av.0 BTS-BSC Inter-operability (Abis Interface) Call Clearing MS, BTS, BSC or MSC will initiate call clearing procedure. The Following messages are exchanged between BSC and BTS. Abis-IS-000 FCH Fwd Abis-IS-000 FCH Rvs Abis-BTS Release Abis-BTS Release Ack Abis-BTS Remove Abis-BTS Remove Ack Abis-BTS Release Request.. Call Clearing initiated by MS... Successful Clear Scenarios For a normal clearing that is initiated by the MS, the MS will send a Release Order to the BTS. The BTS shall send an Abis-IS-000 FCH Rvs message that contains the Release Order message to the BSC. Then BSC sends Clear Request message to the MSC and starts timer T00 to wait for the Clear Command message from the MSC. For packet data calls, call clearing does not normally clear the service session. The service session will be cleared using procedures in this section for conditions such as MS power down, termination of the PPP session by the mobile or the network, etc. In response to the Clear Command message from the MSC, the BSC sends an Abis-IS-000 FCH Fwd message containing the Release Order message. The BTS sends this to the MS on the forward traffic channel to wait for the Abis-Remove Ack message from the BTS. If the BTS receives the Abis-BTS Release message, the BTS starts to releases the radio resource, sends Abis-Remove message to the BSC and starts timer Tdisconb. In response to the Abis-Remove message from the BTS, the BSC sends Abis-Remove Ack message to the BTS. The BTS will stop timer Tdisconb. Then the BTS sends an Abis-BTS Release Ack message to the BSC to acknowledge the completion of the releasing the radio resources. If the BSC receives the Abis-BTS Release Ack message from the BTS, the BSC will stop timer Tdrptgtb and sends a Clear Complete message to the MSC. Then the BSC releases the related terrestrial circuit to the BTS, if allocated. The MSC stops timer T upon receipt of the Clear Complete message. The MSC releases the underlying transport connection. The call flow scenarios are illustrated in section..,.. and...

38 BTS-BSC Inter-operability (Abis Interface) A.S000-Av Unsuccessful Call Clearing Procedures Each node will supervise and detect the unnecessary reserved resource spontaneously, and release it individually.... Abis-IS-000 FCH Rvs See Successful Operation See Failure Operation See Abis-IS-000 FCH Fwd See Successful Operation See Failure Operation See Abis-BTS Release In response to the Clear Command message from the MSC, the BSC sends an Abis-IS-000 FCH Fwd message containing the Release Order message and then the BSC sends an Abis-BTS Release message to the BTS.... Successful Operation The BSC, after sending an Abis-BTS Release message to the BTS and starts timer Tdrptgtb to wait for the Abis-Release Ack message from the BTS. Upon receipt of the Abis-BTS Release message, the BTS releases the associated radio resources. The BTS sends an Abis-BTS Release Ack message to the BSC to acknowledge the clearing of resources at the BTS. Then the BTS sends an Abis-BTS Release Ack message to the BSC to acknowledge the completion of the releasing the radio resources.