09.313GPPBase Station System Application Part LCS Extension (BSSAP-LE)Location Services (LCS)Release 1999TS

This clause specifies the coding of the Information Elements used by the BSSAP-LE protocol. The spare bits in the coding of an IE shall be set to zero by the sender and shall be ignored by the receiver.

All unassigned codes (whether omitted or explicitely Unassigned in the text) shall be treated as unknown (see clause ‘Error Handling and Future Compatibility’).

The following conventions are assumed for the sequence of transmission of bits and bytes:

– Each bit position is marked as 1 to 8. Bit 1 is the least significant bit and is transmitted first.

– In an element octets are identified by number, octet 1 is transmitted first, then octet 2 etc.

When a field extends over more than one octet, the order of bit values progressively decreases as the octet number increases. The least significant bit of the field is represented by the lowest numbered bit of the highest numbered octet of the field.

– For variable length elements a length indicator is included, this indicates the number of octets following in the element.

– All fields within Information Elements are mandatory unless otherwise specified. The Information Element Identifier shall always be included.

All spare bits are set to 0.

For any information element of format TLV, the length indicator octet, as in 3GPP TS 08.08, defines the number of octets in the information element that follow the length indicator octet.

10.1 Message type

Message type uniquely identifies the message being sent. It is a single octet element, mandatory in all messages.

Table 10.1/3GPP TS 09.31: Message type information element

10.2 Information Element Identifiers

The next list shows the coding of the Information Element Identifiers used in the present document.

Table 10.2/3GPP TS 09.31: Information Element Identifier coding

10.3 APDU

This is a variable length information element that conveys an embedded message or message segment associated with a higher level protocol.

Figure 10.3.1/3GPP TS 09.31: APDU IE

Length Indicator (octets 2-3).

The most significant bit is bit 8 of Octet 2, and the least significant bit is bit 1 in Octet 3. The length indicator defines the total number of octets after length indicator.

Protocol ID (bits 7-1 of octet 4).

0000000 reserved

0000001 BSSLAP

0000010 LLP

0000011 SMLCPP

Embedded Message (octets 5-n)

10.4 Cause

This is a variable length information element indicating the reason for sending a Reset message.

Figure 10.4.1/3GPP TS 09.31: Cause IE

10.5 Cell Identifier

This is a variable length information element identifying a particular cell.

Figure 10.5.1/3GPP TS 09.31: Cell Identifier IE

10.6 Chosen Channel

This information element identifiers a type of radio interface channel.

Figure 10.6.1/3GPP TS 09.31: Chosen Channel IE

10.7 Classmark Information Type 3

This information element contains classmark information for a target MS obtained from the MS Classmark 3 defined in 3GPP TS 04.08.

Figure 10.7.1/3GPP TS 09.31: Classmark Information Type 3 IE

10.8 Deciphering Keys

This information element defines the deciphering keys which should used by the MS to decode LCS broadcast assistance data. The parameter includes following data fields. All fields shall be included:

Figure 10.8.1/3GPP TS 09.31: Deciphering Keys IE

Ciphering Key Flag (octet 3)

This flag indicates the current Ciphering Key Flag used in the LCS assistance data broadcast messages in the location area.

Current Deciphering Key Value (octet 4 – 10)

Current Deciphering Key contains the 56 bit deciphering key that is currently in use in location area for deciphering the LCS assistance data broadcast messages.

Next Deciphering Key (octet 11 – 17)

Next Deciphering Key contains the 56 bit deciphering key that will be used next in location area for deciphering the LCS assistance data broadcast messages.

10.9 Geographic Location

This is a variable length information element providing an estimate of a geographic location.

Figure 10.9.1/3GPP TS 09.31: Geographic Location IE

10.10 GPS Assistance Data

This is a variable length information element identifying the GPS assistance data requested for an MS.

Figure 10.10.1/3GPP TS 09.31: GPS Assistance Data IE

Octet 3

bit A Almanac
0 : Almanac is not requested

1 : Almanac is requested

bit B UTC Model
0 : UTC Model is not requested

1 : UTC Model is requested

bit C Ionospheric Model
0 : Ionospheric Model is not requested

1 : Ionospheric Model is requested

bit D Navigation Model
0 : Navigation Model is not requested – octets 5 to 8+2n are not present

1 : Navigation Model is requested – octets 5 to 8+2n are present

bit E DGPS Corrections
0 : DGPS Corrections are not requested

1 : DGPS Corrections are requested

bit F Reference Location
0 : Reference Location is not requested

1 : Reference Location is requested

bit G Reference Time
0 : Reference Time is not requested

1 : Reference Time is requested

bit H Acquisition Assistance

0: Acquisition Assistance is not requested

1: Acquisition Assistance is requested

bit I Real-Time Integrity

0: Real-Time Integrity is not requested

1: Real-Time Integrity is requested

bits J through P are Spare bits

At least one of bits A, B, C, D, E, F, G, H or I, shall be set to the value “1”.

Figure 10.10.2/3GPP TS 09.31: Coding of Satellite Related Data

GPS Week (bits 7-8 octet 5 and octet 6)

This field contains a 10 bit binary representation of the GPS Week of the assistance currently held by the MS. The most significant bit of the GPS Week is bit 8 in octet 5 and the least significant bit is bit 1 in octet 6.

GPS_Toe (octet 7)

This field contains a binary representation of the GPS time of ephemeris in hours of the newest ephemeris set contained in handset memory (range 0-167).

NSAT (octet 8, bits 5-8)

This field contains a binary representation of the number of satellites to be considered for the current GPS assistance request. If the MS has no ephemeris data, this field shall be set to zero. If the MS has ephemeris data whose age exceeds the T-Toe limit, this field may be set to zero. If the SMLC receives a zero value for this field, it shall ignore the GPS Week and GPS_Toe fields and assume that the MS has no ephemeris data.

T-Toe limit (octet 8, bits 1-4)

This field contains a binary representation of the ephemeris age tolerance of the MS to the network in hours (range 0-10).

SatID x (x = 1,2, … n) (octet 7 + 2x, bits 1-6)

This field is present only if NSAT exceeds zero and contains a binary representation of the identity of a satellite for which the assistance request is applicable. The number of satellite fields is indicated in the field NSAT.

IODE x (x = 1,2, … n) (octet 8 + 2x)

This field is present only if NSAT exceeds zero and contains a binary representation of the Issue of Data Ephemeris held in the MS, which identifies the sequence number for the satellite x (x = 1, 2, …, n). The SMLC shall derive the issue date and time for the IODE of each satellite x from the GPS Week and GPS_Toe fields (e.g. when a particular IODE value for a satellite x was issued more than once within the period of T-Toe limit).

10.11 IMSI

The IMSI is of variable length and is coded as a sequence of BCD digits, compressed two into each octet. This is a variable length element, and includes a length indicator. The IMSI is defined in 3GPP TS 03.03. It shall not exceed 15 digits (see 3GPP TS 03.03).

Figure 10.11.1/3GPP TS 09.31: IMSI IE

Where x = (i-2)/2 and i is always even

* The value of the odd/even bit (bit 4 in octect 3) indicates:

0 Even number of IMSI digits

1 Odd number of IMSI digits

If the number of IMSI digits is even then bits 5 to 8 of the last octet shall be filled with an end mark coded as 1111.

10.12 ISDN Address

This information element contains an ISDN address.

Figure 10.12.1/3GPP TS 09.31: ISDN Address IE

10.13 LCS Cause

The LCS Cause parameter is of variable length IE and provides the reason for an unsuccessful location request.

NOTE 1: The inclusion of this octet depends on the cause value.

Figure 10.13.1/3GPP TS 09.31: LCS Cause IE

Table 10.13.1/3GPP TS 09.31: Cause value

Diagnostic value (octet 4):

this octet may be included if the cause value indicates "position method failure", the binary encoding of this octet shall encode the same set of values as defined for the PositionMethodFailure-Diagnostic in 3GPP TS 09.02. Values outside those defined in 3GPP TS 09.02 shall be ignored by a receiver.

10.14 LCS Client Type

This information element identifies the type of LCS Client.

Figure 10.14.1/3GPP TS 09.31: LCS Client Type IE

The client category (bits 8-5 of octet 3) and the client subtype (bits 4-1 of octet 3) are coded as follows.

10.15 LCS Priority

This information element defines the priority level of a location request.

Figure 10.15.1/3GPP TS 09.31: LCS Priority IE

10.16 LCS QoS

This information element defines the Quality of Service for a location request.

Figure 10.16.1/3GPP TS 09.31: LCS QoS IE

Octet 3

VERT = vertical coordinate indicator
0 : vertical coordinate not requested
1 : vertical coordinate is requested

Octet 4

bit 8 HA = horizontal accuracy indicator
0 : Horizontal Accuracy is not specified
1 : Horizontal Accuracy is specified

bits 7-1 Horizontal Accuracy :
spare (set all zeroes) if HA=0
set to 7 bit uncertainty code in 3GPP TS 03.32 if HA=1

Octet 5 – applicable only if VERT = 1

bit 8 VA = vertical accuracy indicator
0 : Vertical Accuracy is not specified
1 : Vertical Accuracy is specified

bits 7-1 Vertical Accuracy :
spare (set all zeroes) if VA=0
set to 7 bit uncertainty altitude code in 3GPP TS 03.32 if VA=1

Octet 6

bits 8-7 RT = response time category
00 : Response Time is not specified
01 : Low Delay
10 : Delay Tolerant
11 : reserved

bits 6-1 spare

10.17 LMU Cause

The LMU Cause parameter provides the reason for the release or rejection of an LMU signaling connection between an MSC and SMLC.

Figure 10.17.1/3GPP TS 09.31: LMU Cause IE

Table 10.17.1/3GPP TS 09.31: Cause value

10.18 Location Type

This is a variable length information element defining the type of location information being requested.

Figure 10.18.1/3GPP TS 09.31: Location Type IE

Coding of location information (octet 3):

00000000 current geographic location
00000001 location assistance information for the target MS
00000010 deciphering keys for broadcast assistance data for the target MS
all other values are reserved

Positioning Method (octet 4)

This octet shall be included if the location information in octet 3 indicates "location assistance information for the target MS" or "deciphering keys for broadcast assistance data for the target MS" and shall be omitted otherwise.

00000000 reserved
00000001 Mobile Assisted E-OTD
00000010 Mobile Based E-OTD
00000011 Assisted GPS
all other values are reserved

10.19 Network Element Identity

This is a variable length information element identifying a network element. by association with either a designated cell site or a designated location area.

Figure 10.19.1/3GPP TS 09.31: Network Element Identity IE

Identity Discriminator (bits 4-1 of octet 3)

0000 Identification using the MCC + MNC +LAC + CI as defined in 3GPP TS 03.03

0001 Identification using LAC + CI as defined in 3GPP TS 03.03

0100 Identification using the MCC + MNC + LAC as defined in 3GPP TS 03.03

0101 Identification using the LAC as defined in 3GPP TS 03.03

All other values are reserved.

Figure 10.19.2/3GPP TS 09.31: Coding of Network Element Identification using the MCC+MNC+LAC+CI

Octets 4 to 10 are coded as the Cell Identification of the Cell Identifier IE for Cell identification discriminator = 0000 defined in 3GPP TS 08.08.

Figure 10.19.3/3GPP TS 09.31: Coding of Network Element Identification using the LAC + CI

Octets 4 to 7 are coded as the Cell Identification of the Cell Identifier IE for Cell identification discriminator = 0001 defined in 3GPP TS 08.08.

Figure 10.19.4/3GPP TS 09.31: Coding of Network Element Identification using the MCC + MNC + LAC

Octets 4 to 8 are coded as the corresponding octets in the Cell Identification of the Cell Identifier List IE for Cell identification discriminator = 0100 defined in 3GPP TS 08.08.

Figure 10.19.5/3GPP TS 09.31: Coding of Network Element Identification using the LAC

Octets 4 to 5 are coded as the corresponding octets in the Cell Identification of the Cell Identifier List IE for Cell identification discriminator = 0101 defined in 3GPP TS 08.08.

10.20 Positioning Data

This is a variable length information element providing positioning data associated with a successful or unsuccessful locatiomn attempt for a target MS.

Figure 10.20.1/3GPP TS 09.31: Positioning Data IE

The positioning data discrminator (bits 4-1 of octet 3) defines the type of data provided for each positioning method:

0000 indicate usage of each positioning method that was attempted either successfully or unsuccessfully

all other values are reserved

Coding of the postioning method octets for positioning data discrminator = 0:

Coding of positioning method (bits 8-4):

00000 Timing Advance
00001 TOA
00010 AOA
00011 Mobile Assisted E-OTD
00100 Mobile Based E-OTD
00101 Mobile Assisted GPS
00110 Mobile Based GPS
00111 Conventional GPS
01000
to reserved for GSM
01111
10000
to reserved for network specific positioning methods
11111

Coding of usage (bits 3-1)

000 Attempted unsuccessfully due to failure or interruption
001 Attempted successfully: results not used to generate location
010 Attempted successfully: results used to verify but not generate location
011 Attempted successfully: results used to generate location
100 Attempted successfully: case where MS supports multiple mobile based positioning methods
and the actual method or methods used by the MS cannot be determined

10.21 Return Error Request

The Return Error Request parameter indicates a request from the source of a BSSMAP-LE connectionless information message for an error response if the message cannot be delivered to its final destination.

Figure 10.21.1/3GPP TS 09.31: Return Error Request IE

Coding of Return Error Type (octet 3):

00000000 Return an unsegmented APDU or the first segment of a segmented APDU; no Return Error shall be sent if no APDU was received or if a subsequent segment of a segmented APDU was received

00000001

to Reserved for future use

11111111

10.22 Return Error Cause

The Return Error Cause parameter provides the reason for unsuccessful delivery of a BSSMAP-LE Connectionless Information message to its final destination.

Figure 10.22.1/3GPP TS 09.31: Return Error Cause IE

Table 10.22.1/3GPP TS 09.31: Cause value

10.23 Security

This information element defines what security measures are needed for signaling to an LMU.

Figure 10.23.1/3GPP TS 09.31: Security IE

Coding of octet 3:

bit 1 AUTH = authentication indicator
0 : authentication of LMU not required
1 : authentication of LMU required

bit 2 CIPH = ciphering indicator
0 : ciphering of LMU signaling data not required
1 : ciphering of LMU signaling data required

10.24 Segmentation

This is a variable length information element that carries information for a segmented APDU.

Figure 10.24.1/3GPP TS 09.31: Segmentation IE

There are two options for the coding of the Segmentation and Message Information portion; 1 octet containing segmentation information only and 3 octets containing segmentation and message information.

Encoding of Segmentation Information:

Figure 10.24.2/3GPP TS 09.31: Segmentation Information

Encoding of Segmentation and Message Information:

Figure 10.24.3/3GPP TS 09.31: Segmentation and Message Information

S (Segmentation Bit, bit 5 of octet 3)

0 final segment of a segmented message

1 non-final segment of a segmented message

Segment Number (bits 4-1 of octet 3)

This field contains a 4 bit binary representation of the segment number. The first segment has the value ‘0000’, the next ‘0001’, and so on.

Message ID (octets 4 and 5)

This field contains a 16 bit binary representation of the message identity, i.e. values 0-65535 are possible.

This field is used to identify to which messages different segments belong to.

10.25 Signaling Point Code

This is a variable length information element providing that provides the signaling point code of a network element.

Figure 10.25.1/3GPP TS 09.31: Signaling Point Code IE

There are three options for the coding of Signaling Point Code value; 2 octets containing a 14 bit ITU code, 3 octets containing a 24 bit unstructured code and 3 octets containing a 24 bit ANSI structured code.

Encoding of 14 bit ITU signaling point code:

Encoding of a 24 bit unstructured signaling point code:

Encoding of a 24 bit ANSI structured signaling point code:

Annex A (informative):
Change history