hash
stringlengths 32
32
| doc_id
stringlengths 7
13
| section
stringlengths 3
121
| content
stringlengths 0
3.82M
|
|---|---|---|---|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.2.1.4 Explicitly disconnect a remote party
|
...................................................................................................... 9
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.2.2 Remote Parties
|
............................................................................................................................................. 9
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.2.2.1 Release from the MultiParty call
|
............................................................................................................ 9
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.2.2.2 Place his connection to the MultiParty call on hold, and typically later retrieve it
|
................................. 9
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3 Managing a held MultiParty call
|
........................................................................................................................ 9
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3.1 Served mobile subscriber
|
............................................................................................................................. 9
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3.1.1 Retrieve the held MultiParty call
|
............................................................................................................ 9
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3.1.2 Initiate a new call
|
.................................................................................................................................. 10
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3.1.3 Process a call waiting request
|
............................................................................................................... 10
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3.1.4 Terminate the held MultiParty call
|
....................................................................................................... 10
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3.1.5 Explicitly disconnect a remote party
|
.................................................................................................... 10
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.3.2 Remote parties
|
............................................................................................................................................ 10
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.4 Managing a single call and a MultiParty call
|
................................................................................................... 10
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.4.1 Served mobile subscriber
|
........................................................................................................................... 10
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.4.1.1 Disconnect the single call
|
..................................................................................................................... 11
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.4.1.2 Disconnect the MPTY
|
.......................................................................................................................... 11
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.4.1.3 Disconnect all calls
|
............................................................................................................................... 11
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.4.1.4 Add the single call to the MPTY
|
.......................................................................................................... 11
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.4.1.5 Alternate between the MPTY call and the single call
|
........................................................................... 11
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.5 Adding extra remote parties
|
............................................................................................................................. 11
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.6 Auxiliary states for MPTY
|
.............................................................................................................................. 12
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.7 Activation, deactivation, registration, erasure and interrogation
|
..................................................................... 12
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
1.8 Simultaneous use of MultiParty operations
|
..................................................................................................... 12 Annex A: Change history......................................................................................................................13 History..............................................................................................................................................................14 ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 4 3G TS 24.084 version 3.0.0 Foreword This Technical Specification has been produced by the 3GPP. This TS specifies the procedures used at the radio interface for normal operation and invocation of MultiParty supplementary services within the 3GPP system. The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of this TS, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version 3.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 Indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the specification; ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 5 3G TS 24.084 version 3.0.0
|
2db8737326eb47c66bc9dbdbc50e66e0
|
124 084
|
0 Scope
|
The present document specifies the procedures used at the radio interface (Reference point Um as defined in GSM 04.02) for normal operation and invocation of MultiParty supplementary services. In GSM 04.10 the general aspects of the specification of supplementary services at the layer 3 radio interface are given. GSM 04.80 specifies the formats and coding for the supplementary services. Definitions and descriptions of supplementary services are given in GSM 02.04 and the GSM 02.8x and GSM 02.9x-series. GSM 02.84 is related specially to MultiParty supplementary services. Technical realization of supplementary services is described in GSM 03.11 and the GSM 03.8x and GSM 03.9x-series. GSM 03.84 is related specially to MultiParty supplementary services. The procedures for Call Control, Mobility Management and Radio Resource management at the layer 3 radio interface are defined in GSM 04.07 and GSM 04.08. The following supplementary service belongs to the MultiParty supplementary services and is described in the present document: - MultiParty service (MPTY) (clause 1). 0.1 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. β’ References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. β’ For a specific reference, subsequent revisions do not apply. β’ For a non-specific reference, the latest version applies. β’ A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. [1] GSM 01.04: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms". [2] GSM 02.04: "Digital cellular telecommunications system (Phase 2+); General on supplementary services". [3] GSM 02.81: "Digital cellular telecommunications system (Phase 2+); Line identification supplementary services - Stage 1". [4] GSM 02.82: "Digital cellular telecommunications system (Phase 2+); Call Forwarding (CF) supplementary services - Stage 1". [5] GSM 02.83: "Digital cellular telecommunications system (Phase 2+); Call Waiting (CW) and Call Hold (HOLD) supplementary services - Stage 1". [6] GSM 02.84: "Digital cellular telecommunications system (Phase 2+); MultiParty (MPTY) supplementary services - Stage 1". [7] GSM 02.85: "Digital cellular telecommunications system (Phase 2+); Closed User Group (CUG) supplementary services - Stage 1". ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 6 3G TS 24.084 version 3.0.0 [8] GSM 02.86: "Digital cellular telecommunications system (Phase 2+); Advice of charge (AoC) supplementary services - Stage 1". [9] GSM 02.88: "Digital cellular telecommunications system (Phase 2+); Call Barring (CB) supplementary services - Stage 1". [10] GSM 02.90: "Digital cellular telecommunications system (Phase 2+); Unstructured Supplementary Services Data (USSD) - Stage 1". [11] GSM 03.11: "Digital cellular telecommunications system (Phase 2+); Technical realization of supplementary services". [12] GSM 03.81: "Digital cellular telecommunications system (Phase 2+); Line identification supplementary services - Stage 2". [13] GSM 03.82: "Digital cellular telecommunications system (Phase 2+); Call Forwarding (CF) supplementary services - Stage 2". [14] GSM 03.83: "Digital cellular telecommunications system (Phase 2+); Call Waiting (CW) and Call Hold (HOLD) supplementary services - Stage 2". [15] GSM 03.84: "Digital cellular telecommunications system (Phase 2+); MultiParty (MPTY) supplementary services - Stage 2". [16] GSM 03.85: "Digital cellular telecommunications system (Phase 2+); Closed User Group (CUG) supplementary services - Stage 2". [17] GSM 03.86: "Digital cellular telecommunications system (Phase 2+); Advice of Charge (AoC) supplementary services - Stage 2". [18] GSM 03.88: "Digital cellular telecommunications system (Phase 2+); Call Barring (CB) supplementary services - Stage 2". [19] GSM 03.90: "Digital cellular telecommunications system (Phase 2+); Unstructured supplementary services operation - Stage 2". [20] GSM 04.02: "Digital cellular telecommunications system (Phase 2+); GSM Public Land Mobile Network (PLMN) access reference configuration". [21] GSM 04.07: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface signalling layer 3; General aspects". [22] GSM 04.08: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specification". [23] GSM 04.10: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3; Supplementary services specification; General aspects". [24] GSM 04.80: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 supplementary services specification; Formats and coding". [25] GSM 04.83: "Digital cellular telecommunications system (Phase 2+); Call Waiting (CW) and Call Hold (HOLD) supplementary services - Stage 3". 0.2 Abbreviations Abbreviations used in the present document are listed in GSM 01.04. ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 7 3G TS 24.084 version 3.0.0 1 MultiParty service (MPTY) 1.1 Beginning the MultiParty service The served mobile subscriber A may initiate an active MultiParty call from an active call C and a held call B. The mobile station invokes the service by sending a FACILITY message to the network containing the BuildMPTY request. This BuildMPTY request indicates to the network that the mobile subscriber wishes all his calls to be connected together in a MultiParty call. The network will normally accept the request and connect the mobile subscriber with the other existing connections (active call C and held call B). If the request is not accepted, the network will indicate the error to the served mobile (see figure 1.1). The network confirms with the same transaction identifier. Error values are specified in GSM 04.80. During the BuildMPTY operation the MS shall run a timer T(BuildMPTY). This timer is started when the operation is sent, and stopped when a response is received from the network. If this timer expires the MS shall assume that the operation has failed, locally release the invokeID, and may re-attempt the operation or inform the user of the failure. MS Network FACILITY (TI A-B/A-C) ------------------------------------------------------------------------------------------------------------------------> Facility (Invoke = BuildMPTY) FACILITY (TI A-B/A-C) <------------------------------------------------------------------------------------------------------------------------ Facility (Return result) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-B/A-C) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Return error (Error)) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-B/A-C) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Reject (Invoke_problem)) NOTE: A-B/A-C indicates a choice. The transaction identifier (TI) used must be that of the active call or the held call. Figure 1.1: Invocation of the MultiParty call If the network received a non-zero SS Screening indicator from the remote party's mobile station the network will also send indications towards the remote parties that the MultiParty call has been invoked, and towards the previously-held party to indicate that he is now retrieved (see figures 1.2 and 1.3). If the network did not receive a non-zero SS Screening indicator from the remote party's mobile station it shall not send a notification. B Network FACILITY (TI A-B) <------------------------------------------------------------------------------------------------------------------------ Facility (Invoke = NotifySS (HOLD, CallOnHold-indicator), Invoke = NotifySS (MPTY, MPTYindicator)) NOTE: The CallOnHold notification (CallOnHold-indicator) sent to the remote subscriber is the same as described in GSM 04.83. Figure 1.2: Notification of invocation to previously-held remote party C Network FACILITY (TI A-C) <------------------------------------------------------------------------------------------------------------------------ Facility (Invoke = NotifySS (MPTY, MPTYindicator)) Figure 1.3: Notification of invocation to previously-active remote party ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 8 3G TS 24.084 version 3.0.0 1.2 Managing an active MultiParty call 1.2.1 Served mobile subscriber During an active MultiParty call the served mobile subscriber can request the network to: 1.2.1.1 Put the MultiParty call on hold This is achieved by sending a FACILITY message to the network with any transaction identifier corresponding to a call within the MultiParty call. This requests the network to place the mobile subscriber's connection to the MultiParty call on hold. The network confirms with another message containing the same transaction identifier (see figure 1.4). During the HoldMPTY operation the MS shall run a timer T(HoldMPTY). This timer is started when the operation is sent, and stopped when a response is received from the network. If this timer expires the MS shall assume that the operation has failed, locally release the invokeID, and may re-attempt the operation or inform the user of the failure. MS Network FACILITY (TI A-X) ------------------------------------------------------------------------------------------------------------------------> Facility (Invoke = HoldMPTY) FACILITY (TI A-X) <------------------------------------------------------------------------------------------------------------------------ Facility (Return result) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-X) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Return error (Error)) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-X) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Reject (Invoke_problem)) NOTE: X = Any remote party in MultiParty call. Figure 1.4: Served mobile subscriber places his connection to the MultiParty call on hold Indications are sent towards all remote parties in the MultiParty call by means of normal CallOnHold notifications as described in GSM 04.83. 1.2.1.2 Create a private communication with one of the remote parties To create a private communication with one of the remote parties, the served mobile will send a SplitMPTY message to the network (see figure 1.5). The network will send normal CallOnHold notifications to the remote parties on hold in the MPTY call. During the SplitMPTY operation the MS shall run a timer T(SplitMPTY). This timer is started when the operation is sent, and stopped when a response is received from the network. If this timer expires the MS shall assume that the operation has failed, locally release the invokeID, and may re-attempt the operation or inform the user of the failure. ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 9 3G TS 24.084 version 3.0.0 MS Network FACILITY (TI A-X) ------------------------------------------------------------------------------------------------------------------------> Facility (Invoke = SplitMPTY) FACILITY (TI A-X) <------------------------------------------------------------------------------------------------------------------------ Facility (Return result) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-X) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Return error (Error)) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-X) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Reject (Invoke_problem)) NOTE: X = Party with which to establish a private communication. Figure 1.5: Served mobile subscriber requests a private communication with a single remote party 1.2.1.3 Terminate the entire MultiParty call The MultiParty call is terminated by disconnecting all individual parties as described in subclause 1.2.1.4. 1.2.1.4 Explicitly disconnect a remote party Any remote party may be individually disconnected by initiation of call clearing as defined in GSM 04.08 with the same transaction identifier corresponding to that party. 1.2.2 Remote Parties During an active MultiParty call any conferee is able to: 1.2.2.1 Release from the MultiParty call In this case, the network will initiate the call clearing procedure towards the served mobile subscriber as defined in GSM 04.08 with the transaction identifier corresponding to the disconnecting party. 1.2.2.2 Place his connection to the MultiParty call on hold, and typically later retrieve it Where a held/retrieved indication is received from any remote party, the network will forward this to the served mobile subscriber (see GSM 04.83). 1.3 Managing a held MultiParty call 1.3.1 Served mobile subscriber During a held MultiParty call the served mobile subscriber can request the network to: 1.3.1.1 Retrieve the held MultiParty call To retrieve the held MultiParty call, a FACILITY message is sent to the network with a transaction identifier corresponding to any call in the MPTY. The network confirms the retrieval with another message containing the same transaction identifier (see figure 1.6). ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 10 3G TS 24.084 version 3.0.0 During the RetrieveMPTY operation the MS shall run a timer T(RetrieveMPTY). This timer is started when the operation is sent, and stopped when a response is received from the network. If this timer expires the MS shall assume that the operation has failed, locally release the invokeID, and may re-attempt the operation or inform the user of the failure. MS Network FACILITY (TI A-X) ------------------------------------------------------------------------------------------------------------------------> Facility (Invoke = RetrieveMPTY) FACILITY (TI A-X) <------------------------------------------------------------------------------------------------------------------------ Facility (Return result) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-X) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Return error (Error)) FACILITY/DISCONNECT/RELEASE/RELEASE COMPLETE (TI A-X) <- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Facility (Reject (Invoke_problem)) NOTE: X = Any remote party in MultiParty call. Figure 1.6: Served mobile subscriber retrieves MultiParty call Indications are sent towards all remote parties by means of normal CallOnHold (= CallRetrieved) notifications as described in GSM 04.83. 1.3.1.2 Initiate a new call This is achieved by normal call set-up procedures (GSM 04.08). 1.3.1.3 Process a call waiting request This is described in GSM 04.83. 1.3.1.4 Terminate the held MultiParty call This is achieved by the same procedure as in subclause 1.2.1.3. 1.3.1.5 Explicitly disconnect a remote party This is achieved by the same procedure as in subclause 1.2.1.4. 1.3.2 Remote parties During a held MultiParty call any remote party is able to perform the same operations as described for an active MultiParty call in subclause 1.2.2. 1.4 Managing a single call and a MultiParty call 1.4.1 Served mobile subscriber If the served mobile subscriber is connected to a MultiParty call (active or on hold) and another single call (active or on hold), he can request the network to: ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 11 3G TS 24.084 version 3.0.0 1.4.1.1 Disconnect the single call This is achieved by using the call clearing procedure as described in GSM 04.08 with the transaction identifier corresponding to the single call. 1.4.1.2 Disconnect the MPTY This is achieved by the same procedure as disconnecting a held/active MPTY without another call (see subclauses 1.2.1 and 1.3.1). 1.4.1.3 Disconnect all calls This is achieved by using the procedures in subclauses 1.4.1.1 and 1.4.1.2. 1.4.1.4 Add the single call to the MPTY The served mobile subscriber may request the connection of all his calls, held and active, into an active MultiParty call at any time by sending a FACILITY message with the transaction identifier corresponding to any remote party and containing the BuildMPTY invoke component (see subclause 1.1). This procedure will apply whether the MultiParty call is on hold or active, and whether the single call is on hold or active. If the request is successful, previously held remote parties will receive an MPTY notification and a CallRetrieved notification as shown in figure 1.2, and previously active remote parties will receive an MPTY notification as shown in figure 1.3. If the network did not receive a non-zero SS Screening indicator from the remote party's mobile station it shall not send a notification. If the request is unsuccessful e.g. because the maximum number of remote parties has already been reached, then an error is returned to the served mobile subscriber, as shown in figure 1.1. Error values are specified in GSM 04.80. 1.4.1.5 Alternate between the MPTY call and the single call This procedure follows the Alternate procedure defined in GSM 04.83 with the exception that the MPTY call is held/retrieved using HoldMPTY/RetrieveMPTY in place of HOLD/RETRIEVE as follows: Single call MPTY call (Facility) HOLD Invoke (HoldMPTY) HOLD ACKNOWLEDGE Return result HOLD REJECT Return error (error) RETRIEVE Invoke (RetrieveMPTY) RETRIEVE ACKNOWLEDGE Return result RETRIEVE REJECT Return error (error) 1.5 Adding extra remote parties Extra remote parties are added by placing the MultiParty call on hold (subclause 1.2.1.1), setting up a new connection (either a new call or a waiting call) and then sending a FACILITY message to the network requesting that the active call be joined with the MPTY, using the same signalling as for invocation (see figure 1.1). This results in an active MultiParty call. Notifications are sent as for the initial invocation (i.e. previously-held parties in MPTY receive CallRetrieved notifications and MPTY notifications; the new remote party only receives an MPTY notification) (see figures 1.2 and 1.3). If the network did not receive a non-zero SS Screening indicator from the remote party's mobile station it shall not send a notification. If the request is not accepted, e.g. because the maximum number of remote parties has already been reached, then the error is indicated to the mobile station. Error values are specified in GSM 04.80. ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 12 3G TS 24.084 version 3.0.0 1.6 Auxiliary states for MPTY In the call hold service (GSM 04.83), a two dimensional state space is defined, where the first dimension corresponds to the GSM 04.08 call control state and the second dimension corresponds to the call hold state (Idle, Hold Request, Call Held, Retrieve Request). For the purposes of the MPTY service, it is necessary to introduce another dimension to this state space, i.e. the MultiParty state. There are four auxiliary states associated with the MPTY service: - Idle; - MPTY request; A request has been made to add this call to the MPTY. - Call in MPTY; This call is in the MPTY. - Split request; A request has been made to remove this call from the MPTY. These Auxiliary states apply in addition to the GSM 04.08 call control states and the GSM 04.83 call hold states. Thus for example, an active call in a held MPTY has the state (Active, Call held, Call in MPTY). Not all states are allowed, for example an MPTY cannot be split while it is held, so (Active, Call held, Split request) is forbidden. 1.7 Activation, deactivation, registration, erasure and interrogation Activation, deactivation, registration, erasure and interrogation of the MultiParty service are not applicable. 1.8 Simultaneous use of MultiParty operations The operations BuildMPTY, SplitMPTY, HoldMPTY and RetrieveMPTY interact with each other, and cannot be applied simultaneously. Once the mobile station has initiated one of these operations, it shall not initiate another MultiParty operation until the first operation has been acknowledged by the network, or the MS locally determines (due to timer expiry) that the first operation has failed. The use of several MultiParty operations as different components in the same message is not allowed. ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 3GPP 3G TS 24.084 V3.0.0 (1999-05) 13 3G TS 24.084 version 3.0.0 Annex A: Change history Change history TSG CN# Spec Version CR <Phase> New Version Subject/Comment Apr 1999 GSM 04.84 6.0.0 Transferred to 3GPP CN1 CN#03 24.084 3.0.0 Approved at CN#03 ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) ETSI 14 ETSI ETSI TS 124 084 V3.0.0 (2000-01) (3G TS 24.084 version 3.0.0 Release 1999) History Document history V3.0.0 January 2000 Publication
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
1 Scope
|
........................................................................................................................................................5
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
2 Normative references
|
...............................................................................................................................5
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
3 Definitions, symbols and abbreviations
|
...................................................................................................6
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
3.1 Definitions
|
......................................................................................................................................................... 6
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
3.2 Symbols
|
............................................................................................................................................................. 6
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
3.3 Abbreviations
|
..................................................................................................................................................... 6
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
4 General
|
.....................................................................................................................................................7
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
5 Functions on the transmit (TX) side
|
........................................................................................................7
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
5.1 LSF evaluation
|
................................................................................................................................................... 8
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
5.2 Frame energy calculation
|
................................................................................................................................... 8
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
5.3 Modification of the speech encoding algorithm during SID frame generation
|
.................................................. 9
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
5.4 SID-frame encoding
|
........................................................................................................................................... 9
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
6 Functions on the receive (RX) side
|
..........................................................................................................9
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
6.1 Averaging and decoding of the LP and energy parameters
|
............................................................................... 9 6. 2 Comfort noise generation and updating........................................................................................................... 10
|
9cfb9318b04cdace4e6b2fc06f7cf91e
|
126 092
|
7 Computational details and bit allocation
|
................................................................................................11 Annex A: Change history......................................................................................................................12 History..............................................................................................................................................................13 (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 4 3G TS 26.092 version 3.0.1 Foreword This Technical Specification has been produced by the 3GPP. The present document defines the detailed requirements for the correct operation of the background acoustic noise evaluation, noise parameter encoding/decoding and comfort noise generation in the narrowband telephony speech service employing the Adaptive Multi-Rate (AMR) speech coder within the 3GPP system. The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of this TS, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version 3.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 Indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the specification; (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 5 3G TS 26.092 version 3.0.1 1 Scope This document gives the detailed requirements for the correct operation of the background acoustic noise evaluation, noise parameter encoding/decoding and comfort noise generation for the AMR speech codec during Source Controlled Rate (SCR) operation. The requirements described in this document are mandatory for implementation in all UEs capable of supporting the AMR speech codec. The receiver requirements are mandatory for implementation in all networks capable of supporting the AMR speech codec, the transmitter requirements only for those where downlink SCR will be used. In case of discrepancy between the requirements described in this document and the fixed point computational description of these requirements contained in [1], the description in [1] will prevail. 2 Normative references This document incorporates by dated and undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this document only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. [1] 3G TS 26.073 : "AMR Speech Codec; ANSI-C code". [2] 3G TS 26.090 : "AMR Speech Codec; Transcoding functions". [3] 3G TS 26.091 : "AMR Speech Codec; Error concealment of lost frames ". [4] 3G TS 26.093 : "AMR Speech Codec; Source Controlled Rate operation ". [5] 3G TS 26.101 : "AMR Speech Codec; Frame Structure". (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 6 3G TS 26.092 version 3.0.1 3 Definitions, symbols and abbreviations 3.1 Definitions For the purpose of this document, the following definitions apply. Frame: Time interval of 20 ms corresponding to the time segmentation of the adaptive multi-rate speech transcoder, also used as a short term for traffic frame. SID frames: Special Comfort Noise frames. It may convey information on the acoustic background noise or inform the decoder that it should start generating background noise. Speech frame: Traffic frame that cannot be classified as a SID frame. VAD flag: Voice Activity Detection flag. TX_TYPE: one of SPEECH, SID_FIRST, SID_UPD, NO_DATA (defined in [4]). RX_TYPE: Classification of the received traffic frame (defined in [4]). Other definitions of terms used in this document can be found in [2] and [4]. The overall operation of SCR is described in [4]. 3.2 Symbols For the purpose of this document , the following symbols apply. Boldface symbols are used for vector variables. [ ] f T f f f = 1 2 10 ... Unquantized LSF vector [ ] ... f T f f f = 1 2 10 Quantized LSF vector f ( ) m Unquantized LSF vector of frame m f ( ) m Quantized LSF vector of frame m f mean Averaged LSF parameter vector enlog Logarithmic frame energy enmean log Averaged logarithmic frame energy f ref Reference vector for LSF quantization e Computed LSF parameter prediction residual e Quantized LSF parameter prediction residual x n n a b ( ) =β ( ) ( ) ( ) ( ) = + + + + β + x a x a x b x b 1 1 3.3 Abbreviations For the purpose of this document , the following abbreviations apply. (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 7 3G TS 26.092 version 3.0.1 AMR Adaptive Multi-Rate SCR Source Controlled Rate operation ( aka source discontinuous transmission ) UE User Equipment SID SIlence Descriptor LP Linear Prediction LSP Line Spectral Pair LSF Line Spectral Frequency RX Receive TX Transmit VAD Voice Activity Detector 4 General A basic problem when using SCR is that the background acoustic noise, which is transmitted together with the speech, would disappear when the transmission is cut, resulting in discontinuities of the background noise. Since the SCR switching can take place rapidly, it has been found that this effect can be very annoying for the listener - especially in a car environment with high background noise levels. In bad cases, the speech may be hardly intelligible. This document specifies the way to overcome this problem by generating on the receive (RX) side synthetic noise similar to the transmit (TX) side background noise. The comfort noise parameters are estimated on the TX side and transmitted to the RX side at a regular rate when speech is not present. This allows the comfort noise to adapt to the changes of the noise on the TX side. 5 Functions on the transmit (TX) side The comfort noise evaluation algorithm uses the following parameters of the AMR speech encoder, defined in [2]: - the unquantized Linear Prediction (LP) parameters, using the Line Spectral Pair (LSP) representation, where the unquantized Line Spectral Frequency (LSF) vector is given by [ ] f T f f f = 1 2 10 ... ; - the unquantized LSF vector for the 12.2 kbit/s mode is given by the second set of LSF parameters in the frame. The algorithm computes the following parameters to assist in comfort noise generation: - the averaged LSF parameter vector f mean (average of the LSF parameters of the eight most recent frames); - the averaged logarithmic frame energy enmean log (average of the logarithmic energy of the eight most recent frames). These parameters give information on the level (enmean log ) and the spectrum ( f mean ) of the background noise. The evaluated comfort noise parameters ( f mean andenmean log ) are encoded into a special frame, called a Silence Descriptor (SID) frame for transmission to the RX side. A hangover logic is used to enhance the quality of the silence descriptor frames. A hangover of seven frames is added to the VAD flag so that the coder waits with the switch from active to inactive mode for a period of seven frames, during that time the decoder can compute a silence descriptor frame from the quantized LSFs and the logarithmic frame energy of the decoded speech signal. Therefore, no comfort noise description is transmitted in the first SID frame after active speech. If the background noise contains transients which will cause the coder to switch to active mode and then back to inactive mode in a very short timeperiod, no hangover is used. Instead the previously used comfort noise frames are used for comfort noise generation. (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 8 3G TS 26.092 version 3.0.1 The first SID frame also serves to initiate the comfort noise generation on the receive side, as a first SID frame is always sent at the end of a speech burst, i.e., before the transmission is terminated. The scheduling of SID or speech frames on the network path is described in [4]. 5.1 LSF evaluation The comfort noise parameters to be encoded into a SID frame are calculated over N = 8 consecutive frames marked with VAD=0, as follows: The averaged LSF parameter vector ( ) f mean i of the frame i shall be computed according to the equation: ( ) f f mean n i i n = β =β 1 8 0 7 ( ) (1) where ( ) f i n β is the (unquantized) LSF parameter vector of the current frame i ( n = 0) and past frames (n = 1 7 , , ). The averaged LSF parameter vector ( ) f mean i of the frame i is encoded using the same encoding tables that are also used by the 7.4 kbit/s mode for the encoding of the non-averaged LSF parameter vectors in ordinary speech encoding mode, but the quantization algorithm is modified in order to support the quantization of comfort noise. The LSF parameter prediction residual to be quantized for frame i is obtained according to the following equation: ( ) ( ) e f f i i mean ref = β (2) where f ref is a reference vector picked from a codebook. The vector f ref used in eq (2) is encoded for each SID frame. A lookup table containing 8 vectors typical for background noise are searched. The vector which yields the lowest prediction residual energy is selected. After the above step the LSF parameter encoding procedure is performed. The 3-bit index for the reference vector and the 26 bits for LSF parameter are transmitted in the SID frame (see bit allocation in table 1). 5.2 Frame energy calculation The frame energy is computed for each frame marked with VAD=0 according to the equation : ( ) ( ) en i N s n n N log log =  ο£ο£¬ ο£Ά ο£Έο£· = β β 1 2 1 2 2 0 1 (3) where ( ) s n is the HP-filtered input speech signal of the current frame i. The averaged logarithmic energy is computed by: ( ) en i en i n mean n log log( ) = β =β 1 8 0 7 . (4) The averaged logarithmic energy is quantized means of a 6 bit algorithmic quantizer. The 6 bits for the energy index are transmitted in the SID frame (see bit allocation in table 1). (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 9 3G TS 26.092 version 3.0.1 5.3 Modification of the speech encoding algorithm during SID frame generation When the TX_TYPE is not equal to SPEECH the speech encoding algorithm is modified in the following way: - The non-averaged LP parameters which are used to derive the filter coefficients of the filters ( ) H z and ( ) W z of the speech encoder are not quantized; - The open loop pitch lag search is performed, but the closed loop pitch lag search is inactivated. The adaptive codebook gain and memory is set to zero. - No fixed codebook search is made. - The memory of weighting filter ( ) W z is set to zero, i.e., the memory of ( ) W z is not updated. - The ordinary LP parameter quantization algorithm is inactive. The averaged LSF parameter vector f mean is calculated each time a new SID frame is to be sent to the AN. This parameter vector is encoded into the SID frame as defined in subclause 5.1. - The ordinary gain quantization algorithm is inactive. - The predictor memories of the ordinary LP parameter quantization and fixed codebook gain quantization algorithms are initialized when TX_TYPE is not SPEECH, so that the quantizers start from known initial states when the speech activity begins again. 5.4 SID-frame encoding The encoding of the comfort noise bits in a SID frame is described in [5] where the indication of the first SID frame is also described. The bit allocation and sequence of the bits from comfort noise encoding is shown in Table 1. 6 Functions on the receive (RX) side The situations in which comfort noise shall be generated on the receive side are defined in [4]. In general, the comfort noise generation is started or updated whenever a valid SID frame is received. 6.1 Averaging and decoding of the LP and energy parameters When speech frames are received by the decoder the LP and the energy parameters of the last seven speech frames shall be kept in memory. The decoder counts the number of frames elapsed since the last SID frame was updated and passed to the RSS by the encoder. Based on this count, the decoder determines whether or not there is a hangover period at the end of the speech burst (defined in[4] ). The interpolation factor is also adapted to the SID update rate. As soon as a SID frame is received comfort noise is generated at the decoder end. The first SID frame parameters are not received but computed from the parameters stored during the hangover period. If no hangover period is detected, the parameters from the previous SID update are used. The averaging procedure for obtaining the comfort noise parameters for the first SID frame is as follows: - when a speech frame is received, the LSF vector is decoded and stored in memory, moreover the logarithmic frame energy of the decoded signal is also stored in memory. - the averaged values of the quantized LSF vectors and the averaged logarithmic frame energy of the decoded frames are computed and used for comfort noise generation. The averaged value of the LSF vector for the first SID frame is given by: (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 10 3G TS 26.092 version 3.0.1 ( ) ( ) β = β = 7 0 Λ 8 1 Λ n mean n i i f f (5) where ( ) f i n β , n > 0 is the quantized LSF vector of one of the frames of the hangover period and where ( ) 0 Λ β i f = ( ) 1 Λ β i f . The averaged logarithmic frame energy for the first SID frame is given by: ( ) ( ) β = β = 7 0 log log Λ 8 1 Λ n mean n i n e i n e (6) where ( ) log en i n β , n > 0 is the logaritmic vector of one of the frames of the hangover period computed for the decoded frames and where ( ) 0 Λ log β i n e = ( ) 1 Λ log β i n e . For ordinary SID frames, the LSF vector and logarithmic frame energy are computed by table lookup. The energy is also adjusted according to the signalled speech modes capabilities, as to provide high quality transitions from Comfort Noise to Speech. The LSF vector is given by the sum of the decoded reference vector and the decoded LSF prediction residual. During comfort noise generation the spectrum and energy of the comfort noise is determined by interpolation between old and new SID frames. In order to achieve a comfort noise that is less static in appearance the LSF vector is slightly perturbed for each frame by adding a small component based on parameters variations computed in the hangover period. The computation of the perturbation is made by computing the mean LSF vector from the matrix f , this mean vector is then subtracted from each of the elements of f forming a new matrix f . For every frame a mean removed LSF vector is randomly choosen from f and added to the interpolated LSF vector. 6. 2 Comfort noise generation and updating The comfort noise generation procedure uses the adaptive multi-rate speech decoder algorithm defined in [2]. When comfort noise is to be generated, the various encoded parameters are set as follows: In each subframe, the pulse positions and signs of the fixed codebook excitation are locally generated using uniformly distributed pseudo random numbers. The excitation pulses take values of +1 and -1 when comfort noise is generated. The fixed codebook comfort noise excitation generation algorithm works as follows: for (i = 0; i < 40; i++) code[i] = 0; for (i = 0; i < 10; i++) { j = random(4); idx = j * 10 + i; if (random(2) == 1) code[idx] = 1; else code[idx] = -1; } where: code[0..39] fixed codebook excitation buffer; random(4) generates a random integer value, uniformly distributed between 0 and 3; (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 11 3G TS 26.092 version 3.0.1 random(2) generates a random integer value, uniformly distributed between 0 and 1. The fixed codebook gain is computed from the logarithmic frame energy parameter by converting it to the linear domain and normalizing with the gain of LP synthesis filter. The adaptive codebook gain values in each subframe are set to 0, also the memory of the adaptive codebook is set to zero. The pitch delay values in each subframe are set to 40. The LP filter parameters used are those received in the SID frame. The predictor memories of the ordinary LP parameter and fixed codebook gain quantization algorithms are initialized when RX_TYPE is not SPEECH , so that the quantizers start from given initial states when the speech activity begins again. With these parameters, the speech decoder now performs the standard operations described in [2] and synthesizes comfort noise. Updating of the comfort noise parameters (energy and LP filter parameters) occurs each time a valid SID frame is received, as described in [4]. When updating the comfort noise, the parameters above should be interpolated over the SID update period to obtain smooth transitions. A bit exact computational description of comfort noise encoding and generation in form of an ANSI-C source code is found in [1]. The detailed bit allocation and the sequence of bits in the comfort noise encoding is shown in Table 1. Table 1: Source encoder output parameters in order of occurrence and bit allocation for comfort noise encoding. Bits (MSB-LSB) Description s1 β s3 index of reference vector s4 - s11 index of 1st LSF subvector s12 β s20 index of 2nd LSF subvector s21 β s29 index of 3rd LSF subvector s30 β s35 index of logarithmic frame energy (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 3GPP 3G TS 26.092 V3.0.1 (1999-08) 12 3G TS 26.092 version 3.0.1 Annex A: Change history Document history V. 0.1.0 March 1999 First Draft based on GSM 06.92 2.0.0 V. 0.2.1 April 1999 Presented in S4#4 V. 1.0.0 April 22, 1999 Editorial updates V. 2.0.0 June 21, 1999 Presented at S#4 Plenary for approval V. 3.0.0 June 22, 1999 Approved at S#4 Plenary V. 3.0.1 August 22, 1999 Reformatted in 3GPP style (3G TS 26.092 version 3.0.1 Release 1999) ETSI TS 126 092 V3.0.1 (2000-01) ETSI 13 ETSI ETSI TS 126 092 V3.0.1 (2000-01) (3G TS 26.092 version 3.0.1 Release 1999) History Document history V3.0.1 January 2000 Publication
|
b738be600defdc5decba60fb085dc736
|
126 091
|
1 Scope
|
........................................................................................................................................................5
|
b738be600defdc5decba60fb085dc736
|
126 091
|
2 Normative references
|
...............................................................................................................................5
|
b738be600defdc5decba60fb085dc736
|
126 091
|
3 Definitions and abbreviations
|
..................................................................................................................5
|
b738be600defdc5decba60fb085dc736
|
126 091
|
3.1 Definitions
|
......................................................................................................................................................... 5
|
b738be600defdc5decba60fb085dc736
|
126 091
|
3.2 Abbreviations
|
..................................................................................................................................................... 6
|
b738be600defdc5decba60fb085dc736
|
126 091
|
4 General
|
.....................................................................................................................................................6
|
b738be600defdc5decba60fb085dc736
|
126 091
|
5 Requirements
|
...........................................................................................................................................6
|
b738be600defdc5decba60fb085dc736
|
126 091
|
5.1 Error detection
|
................................................................................................................................................... 6
|
b738be600defdc5decba60fb085dc736
|
126 091
|
5.2 Lost speech frames
|
............................................................................................................................................. 6
|
b738be600defdc5decba60fb085dc736
|
126 091
|
5.3 First lost SID frame
|
............................................................................................................................................ 7
|
b738be600defdc5decba60fb085dc736
|
126 091
|
5.4 Subsequent lost SID frames
|
............................................................................................................................... 7 6 Example ECU/BFH Solution 1................................................................................................................7
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.1 State Machine
|
.................................................................................................................................................... 7
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.2 Assumed Active Speech Frame Error Concealment Unit Actions
|
..................................................................... 8
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.2.1 BFI = 0, prevBFI = 0, State = 0
|
.................................................................................................................... 8
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.2.2 BFI = 0, prevBFI = 1, State = 0 or 5
|
............................................................................................................ 8
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.2.3 BFI = 1, prevBFI = 0 or 1, State = 1...6
|
....................................................................................................... 9
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.2.3.1 LTP-lag update
|
....................................................................................................................................... 9
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.2.3.2 Innovation sequence
|
............................................................................................................................. 10
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.3 Assumed Non-Active Speech Signal Error Concealment Unit Actions
|
.......................................................... 10
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.3.1 General
|
....................................................................................................................................................... 10
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.3.2 Detectors
|
.................................................................................................................................................... 10
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.3.2.1 Background detector
|
............................................................................................................................. 10
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.3.2.2 Voicing detector
|
................................................................................................................................... 10
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.3.3 Background ECU Actions
|
.......................................................................................................................... 10
|
b738be600defdc5decba60fb085dc736
|
126 091
|
6.4 Substitution and muting of lost SID frames
|
..................................................................................................... 10 7 Example ECU/BFH Solution 2..............................................................................................................11
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.1 State Machine
|
.................................................................................................................................................. 11
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.2 Substitution and muting of lost speech frames
|
................................................................................................ 11
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.2.1 BFI = 0, prevBFI = 0, State = 0
|
.................................................................................................................. 11
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.2.2 BFI = 0, prevBFI = 1, State = 0 or 5
|
.......................................................................................................... 11
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.2.3 BFI = 1, prevBFI = 0 or 1, State = 1...6
|
..................................................................................................... 12
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.2.3.1 LTP-lag update
|
..................................................................................................................................... 12
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.2.4 Innovation sequence
|
................................................................................................................................... 12
|
b738be600defdc5decba60fb085dc736
|
126 091
|
7.3 Substitution and muting of lost SID frames
|
..................................................................................................... 12 Annex A: Change history......................................................................................................................13 History..............................................................................................................................................................14 (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 4 3G TS 26.091 version 3.1.0 Foreword This Technical Specification has been produced by the 3GPP. The present document defines an error concealment procedure, also termed frame substitution and muting procedure, of the narrowband telephony speech service employing the Adaptive Multi-Rate (AMR) speech coder within the 3GPP system. The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of this TS, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version 3.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 Indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the specification; (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 5 3G TS 26.091 version 3.1.0 1 Scope This specification defines an error concealment procedure, also termed frame substitution and muting procedure, which shall be used by the AMR speech codec receiving end when one or more lost speech or lost Silence Descriptor (SID) frames are received. The requirements of this document are mandatory for implementation in all networks and User Equipment (UE)s capable of supporting the AMR speech codec. It is not mandatory to follow the bit exact implementation outlined in this document and the corresponding C source code. 2 Normative references This document incorporates, by dated and undated reference, provisions from other publications. These normative references are cited in the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this document only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. [1] 3G TS 26.102 "AMR Speech Codec; Interface to RAN". [2] 3G TS 26.090 "AMR Speech Codec; Transcoding functions". [3] 3G TS 26.093 "AMR Speech Codec; Source Controlled Rate operation". [4] 3G TS 26.101 "AMR Speech Codec; Frame structure". 3 Definitions and abbreviations 3.1 Definitions For the purposes of this document, the following definition applies: N-point median operation: Consists of sorting the N elements belonging to the set for which the median operation is to be performed in an ascending order according to their values, and selecting the (int (N/2) + 1) -th largest value of the sorted set as the median value. Further definitions of terms used in this document can be found in the references. (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 6 3G TS 26.091 version 3.1.0 3.2 Abbreviations For the purposes of this document, the following abbreviations apply: AN Access Network BFI Bad Frame Indication from AN BSI_netw Bad Sub-block Indication obtained from AN interface CRC checks prevBFI Bad Frame Indication of previous frame PDFI Potentially Degraded Frame Indication RX Receive SCR Source Controlled Rate (operation) SID Silence Descriptor frame (Background descriptor) CRC Cyclic Redundancy Check ECU Error Concealment Unit BFH Bad Frame Handling medianN N-point median operation 4 General The purpose of the error concealment procedure is to conceal the effect of lost AMR speech frames. The purpose of muting the output in the case of several lost frames is to indicate the breakdown of the channel to the user and to avoid generating possible annoying sounds as a result from the error concealment procedure. The network shall indicate lost speech or lost SID frames by setting the RX_TYPE values [3] to SPEECH_BAD or SID_BAD. If these flags are set, the speech decoder shall perform parameter substitution to conceal errors. The network should also indicate potentially degraded frames using the flag RX_TYPE value SPEECH_PROBABLY_DEGRADED. This flag may be derived from channel quality indicators. It may be used by the speech decoder selectively depending on the estimated signal type. The example solutions provided in paragraphs 6 and 7 apply only to bad frame handling on a complete speech frame basis. Sub-frame based error concealment may be derived using similar methods. 5 Requirements 5.1 Error detection If the most sensitive bits of the AMR speech data (class A in [4]) are received in error, the network shall indicate RX_TYPE = SPEECH_BAD in which case the BFI flag is set. If a SID frame is received in error, the network shall indicate RX_TYPE = SID_BAD in which case the BFI flag is also set. The RX_TYPE = SPEECH_PROBABLY_DEGRADED flag should be set appropriately using quality information from the channel decoder, in which case the PDFI flas is set. 5.2 Lost speech frames Normal decoding of lost speech frames would result in very unpleasant noise effects. In order to improve the subjective quality, lost speech frames shall be substituted with either a repetition or an extrapolation of the previous good speech frame(s). This substitution is done so that it gradually will decrease the output level, resulting in silence at the output. Subclauses 6, and 7 provide example solutions. (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 7 3G TS 26.091 version 3.1.0 5.3 First lost SID frame A lost SID frame shall be substituted by using the SID information from earlier received valid SID frames and the procedure for valid SID frames be applied as described in [3]. 5.4 Subsequent lost SID frames For many subsequent lost SID frames, a muting technique shall be applied to the comfort noise that will gradually decrease the output level. For subsequent lost SID frames, the muting of the output shall be maintained. Subclauses 6 and 7 provide example solutions. 6 Example ECU/BFH Solution 1 The C code of the following example is embedded in the bit exact software of the codec. In the code the ECU is designed to allow subframe-by-subframe synthesis, thereby reducing the speech synthesis delay to a minimum. 6.1 State Machine This example solution for substitution and muting is based on a state machine with seven states (Figure 1). The system starts in state 0. Each time a bad frame is detected, the state counter is incremented by one and is saturated when it reaches 6. Each time a good speech frame is detected, the state counter is reset to zero, except when we are in state 6, where we set the state counter to 5. The state indicates the quality of the channel: the larger the value of the state counter, the worse the channel quality is. The control flow of the state machine can be described by the following C code (BFI = bad frame indicator, State = state variable): if(BFI != 0 ) State = State + 1; else if(State == 6) State = 5; else State = 0; if(State > 6 ) State = 6; In addition to this state machine, the Bad Frame Flag from the previous frame is checked (prevBFI). The processing depends on the value of the State-variable. In states 0 and 5, the processing depends also on the two flags BFI and prevBFI. (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 8 3G TS 26.091 version 3.1.0 The procedure can be described as follows: STATE = 0 BFI = 0 PrevBFI = 0 or 1 STATE = 1 BFI = 1 PrevBFI = 0 STATE = 2 BFI = 1 PrevBFI = 1 STATE = 3 BFI = 1 PrevBFI = 1 STATE = 5 BFI = 0 or 1 PrevBFI = 1 STATE = 6 BFI = 1 PrevBFI = 0 or 1 Good frame (BFI=0) Bad frame (BFI=1) STATE = 4 BFI = 1 PrevBFI = 1 Figure 1: State machine for controlling the bad frame substitution 6.2 Assumed Active Speech Frame Error Concealment Unit Actions 6.2.1 BFI = 0, prevBFI = 0, State = 0 No error is detected in the received or in the previous received speech frame. The received speech parameters are used in the normal way in the speech synthesis. The current frame of speech parameters is saved. 6.2.2 BFI = 0, prevBFI = 1, State = 0 or 5 No error is detected in the received speech frame, but the previous received speech frame was bad. The LTP gain and fixed codebook gain are limited below the values used for the last received good (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 9 3G TS 26.091 version 3.1.0 subframe: ( ) ( ) ( ) g g g g g g g p p p p p p p = β€ β β > β ο£± ο£² ο£³ , , 1 1 1 (1) where g p = current decoded LTP gain, ( ) g p β1 = LTP gain used for the last good subframe (BFI = 0), and ( ) ( ) ( ) g g g g g g g c c c c c c c = β€ β β > β ο£± ο£² ο£³ , , 1 1 1 (2) where gc = current decoded fixed codebook gain and ( ) gc β1 = fixed codebook gain used for the last good subframe (BFI = 0). The rest of the received speech parameters are used normally in the speech synthesis. The current frame of speech parameters is saved. 6.2.3 BFI = 1, prevBFI = 0 or 1, State = 1...6 An error is detected in the received speech frame and the substitution and muting procedure is started. The LTP gain and fixed codebook gain are replaced by attenuated values from the previous subframes: g P state g g median g g P state median g g g median g g p p p p p p p p p p = β β β€ β β β β β > β β ο£±   ( ) ( ), ( ) ( ( ),..., ( )) ( ) ( ( ),..., ( )), ( ) ( ( ),..., ( )) 1 1 5 1 5 5 1 5 1 5 1 5 (3) where g p = current decoded LTP gain, g g n p p ( ),..., ( ) β β 1 = LTP gains used for the last n subframes, median5() = 5-point median operation, P(state) = attenuation factor (P(1) = 0.98, P(2) = 0.98, P(3) = 0.8, P(4) = 0.3, P(5) = 0.2, P(6) = 0.2), state = state number, and g C state g g median g g C state median g g g median g g c c c c c c c c c c = β β β€ β β β β β > β β ο£±   ( ) ( ), ( ) ( ( ),..., ( )) ( ) ( ( ),..., ( )), ( ) ( ( ),..., ( )) 1 1 5 1 5 5 1 5 1 5 1 5 (4) where gc = current decoded fixed codebook gain, g g n c c ( ),..., ( ) β β 1 = fixed codebook gains used for the last n subframes, median5() = 5-point median operation, C(state) = attenuation factor (C(1) = 0.98, C(2) = 0.98, C(3) = 0.98, C(4) = 0.98, C(5) = 0.98, C(6) = 0.7), and state = state number. The higher the state value is, the more the gains are attenuated. Also the memory of the predictive fixed codebook gain is updated by using the average value of the past four values in the memory: ( ) ( ) ener ener i i 0 1 4 1 4 = β =β (5) The past LSFs are shifted towards their mean: ( ) ( ) ( ) ( ) lsf q i lsf q i past lsf q i mean lsf i i _ _ _ _ ( ) _ , ... 1 2 1 0 9 = = + β = Ξ± Ξ± (6) where Ξ± = 0.95, lsf_q1 and lsf_q2 are two sets of LSF-vectors for current frame, past_lsf_q is lsf_q2 from the previous frame, and mean_lsf is the average LSF-vector. Note that two sets of LSFs are available only in the 12.2 mode. 6.2.3.1 LTP-lag update The LTP-lag values are replaced by the past value from the 4th subframe of the previous frame (12.2 mode) or slightly modified values based on the last correctly received value (all other modes). (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 10 3G TS 26.091 version 3.1.0 6.2.3.2 Innovation sequence The received fixed codebook innovation pulses from the erroneous frame are used in the state in which they were received when corrupted data are received . In the case when no data were received random fixed codebook indicies should be employed. 6.3 Assumed Non-Active Speech Signal Error Concealment Unit Actions 6.3.1 General The Non-Active Speech ECU is used to reduce the negative impact of amplitude variations and tonal artifacts when using the conventional Active Speech ECU in non-voiced signals such as background noise and unvoiced speech. The background ECU actions are only used for the lower rate Speech Coding modes. The Non-Active Speech ECU actions are done as postprocessing actions of the Active Speech ECU, actions thus ensuring that the Active Speech ECU states are continuously updated. This will guarantee instant and seamless switching to the Active Speech ECU. The detectors and state updates have to be running continuously for all speech coding modes to avoid switching problems. Only the differences to the Active Speech ECU are stated below. 6.3.2 Detectors 6.3.2.1 Background detector An energy level and energy change detector is used to monitor the signal. If the signal is considered to contain background noise and only shows minor energy level changes, a flag is set. The resulting indicator is the inBackgroundNoise flag which indicates the signal state of the previous frame. 6.3.2.2 Voicing detector The received LTP gain is monitored and used to prevent the use of the background ECU actions in possibly voiced segments. A median filtered LTP gain value with a varying filter memory length is thresholded to provide the correct voicing decision. Additionally, a counter voicedHangover is used to monitor the time since a frame was presumedly voiced. 6.3.3 Background ECU Actions The BFI, and DFI indications are used together with the flag inBackgroundNoise and the counter voicedHangover to adjust the LTP part and the innovation part of the excitation. The actions are only taken if the previous frame has been classified as background noise and sufficient time has passed since the last voiced frame was detected. The background ECU actions are: energy control of the excitation signal, relaxed LTP lag control, stronger limitation of the LTP gain, adjusted adaptation of the Gain-Contour-Smoothing algorithm and modified adaptation of the Anti- Sparseness Procedure. 6.4 Substitution and muting of lost SID frames In the speech decoder a single frame classified as SID_BAD shall be substituted by the last valid SID frame information and the procedure for valid SID frames be applied. If the time between SID information updates (updates are specified by SID_UPDATE arrivals and ocassionally by SID_FIRST arrivals see 06.92) is greater than one second this shall lead to attenuation. (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 11 3G TS 26.091 version 3.1.0 7 Example ECU/BFH Solution 2 This is an alternative example solution which is a simplified version of Example ECU/BFH Solution 1. 7.1 State Machine This example solution for substitution and muting is based on a state machine with seven states (Figure 1, same state machine as in Example 1). The system starts in state 0. Each time a bad frame is detected, the state counter is incremented by one and is saturated when it reaches 6. Each time a good speech frame is detected, the state counter is reset to zero, except when we are in state 6, where we set the state counter to 5. The state indicates the quality of the channel: the larger the state counter, the worse the channel quality is. The control flow of the state machine can be described by the following C code (BFI = bad frame indicator, State = state variable): if(BFI != 0 ) State = State + 1; else if(State == 6) State = 5; else State = 0; if(State > 6 ) State = 6; In addition to this state machine, the Bad Frame Flag from the previous frame is checked (prevBFI). The processing depends on the value of the State-variable. In states 0 and 5, the processing depends also on the two flags BFI and prevBFI. 7.2 Substitution and muting of lost speech frames 7.2.1 BFI = 0, prevBFI = 0, State = 0 No error is detected in the received or in the previous received speech frame. The received speech parameters are used normally in the speech synthesis. The current frame of speech parameters is saved. 7.2.2 BFI = 0, prevBFI = 1, State = 0 or 5 No error is detected in the received speech frame but the previous received speech frame was bad. The LTP gain and fixed codebook gain are limited below the values used for the last received good subframe: ( ) ( ) ( ) g g g g g g g p p p p p p p = β€ β β > β ο£± ο£² ο£³ , , 1 1 1 (7) where g p = current decoded LTP gain, ( ) g p β1 = LTP gain used for the last good subframe (BFI = 0), and ( ) ( ) ( ) g g g g g g g c c c c c c c = β€ β β > β ο£± ο£² ο£³ , , 1 1 1 (8) where gc = current decoded fixed codebook-gain and ( ) gc β1 = fixed codebook gain used for the last good subframe (BFI = 0). The rest of the received speech parameters are used normally in the speech synthesis. The current frame of speech parameters is saved. (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 12 3G TS 26.091 version 3.1.0 7.2.3 BFI = 1, prevBFI = 0 or 1, State = 1...6 An error is detected in the received speech frame and the substitution and muting procedure is started. The LTP gain and fixed codebook gain are replaced by attenuated values from the previous subframes: g P state g g median g g P state median g g g median g g p p p p p p p p p p = β β β€ β β β β β > β β ο£±   ( ) ( ), ( ) ( ( ),..., ( )) ( ) ( ( ),..., ( )), ( ) ( ( ),..., ( )) 1 1 5 1 5 5 1 5 1 5 1 5 (9) where g p = current decoded LTP gain, g g n p p ( ),..., ( ) β β 1 = LTP gains used for the last n subframes, median5() = 5-point median operation, P(state) = attenuation factor (P(1) = 0.98, P(2) = 0.98, P(3) = 0.8, P(4) = 0.3, P(5) = 0.2, P(6) = 0.2), state = state number, and g C state g g median g g C state median g g g median g g c c c c c c c c c c = β β β€ β β β β β > β β ο£±   ( ) ( ), ( ) ( ( ),..., ( )) ( ) ( ( ),..., ( )), ( ) ( ( ),..., ( )) 1 1 5 1 5 5 1 5 1 5 1 5 (10) where gc = current decoded fixed codebook gain, g g n c c ( ),..., ( ) β β 1 = fixed codebook gains used for the last n subframes, median5() = 5-point median operation, C(state) = attenuation factor (C(1) = 0.98, C(2) = 0.98, C(3) = 0.98, C(4) = 0.98, C(5) = 0.98, C(6) = 0.7), and state = state number. The higher the state value is, the more the gains are attenuated. Also the memory of the predictive fixed codebook gain is updated by using the average value of the past four values in the memory: ( ) ( ) ener ener i i 0 1 4 1 4 = β =β (11) The past LSFs are used by shifting their values towards their mean: ( ) ( ) ( ) ( ) lsf q i lsf q i past lsf q i mean lsf i i _ _ _ _ ( ) _ , ... 1 2 1 0 9 = = + β = Ξ± Ξ± (12) where Ξ± = 0.95, lsf_q1 and lsf_q2 are two sets of LSF-vectors for current frame, past_lsf_q is lsf_q2 from the previous frame, and mean_lsf is the average LSF-vector. Note that two sets of LSFs are available only in the 12.2 mode. 7.2.3.1 LTP-lag update The LTP-lag values are replaced by the past value from the 4th subframe of the previous frame (12.2 mode) or slightly modified values based on the last correctly received value (all other modes). 7.2.4 Innovation sequence The received fixed codebook innovation pulses from the erroneous frame are used in the state in which they were received when corrupted data are received. In the case when no data were received random fixed codebook indicies should be employed. In the speech decoder a single frame classified as SID_BAD shall be substituted by the last valid SID frame information and the procedure for valid SID frames be applied. If the time between SID information updates (updates are specified by SID_UPDATE arrivals and occasionally by SID_FIRST arrivals) is greater than one second this shall lead to attenuation. (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 3GPP 3G TS 26.091 V3.1.0 (1999-12) 13 3G TS 26.091 version 3.1.0 Annex A: Change history Tdoc SPEC CR RE VER SUBJECT CAT NEW SP-99570 26.091 A001 3.0.1 Use of random excitation when RX_NODATA and not in DTX F 3.1.0 (3G TS 26.091 version 3.1.0 Release 1999) ETSI TS 126 091 V3.1.0 (2000-01) ETSI 14 ETSI ETSI TS 126 091 V3.1.0 (2000-01) (3G TS 26.091 version 3.1.0 Release 1999) History Document history V3.1.0 January 2000 Publication
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
1 Scope
|
....................................................................................................................................................... 6
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
2 Normative references
|
............................................................................................................................... 6
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
3 Definitions, symbols and abbreviations
|
................................................................................................... 7
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
3.1 Definitions
|
..........................................................................................................................................................7
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
3.2 Symbols
|
..............................................................................................................................................................8
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
3.3 Abbreviations
|
...................................................................................................................................................14
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
4 Outline description
|
................................................................................................................................ 14
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
4.1 Functional description of audio parts
|
...............................................................................................................14
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
4.2 Preparation of speech samples
|
..........................................................................................................................15
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
4.2.1 PCM format conversion
|
..............................................................................................................................15
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
4.3 Principles of the adaptive multi-rate speech encoder
|
.......................................................................................16
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
4.4 Principles of the adaptive multi-rate speech decoder
|
.......................................................................................18
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
4.5 Sequence and subjective importance of encoded parameters
|
...........................................................................19
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5 Functional description of the encoder
|
................................................................................................... 19 5.1 Pre-processing (all modes) ...............................................................................................................................19
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.2 Linear prediction analysis and quantization
|
.....................................................................................................19 12.2 kbit/s mode 19 10.2, 7.95, 7.40, 6.70, 5.90, 5.15, 4.75 kbit/s modes.........................................................................................................19 5.2.1 Windowing and auto-correlation computation............................................................................................20 12.2 kbit/s mode 20 10.2, 7.95, 7.40, 6.70, 5.90, 5.15, 4.75 kbit/s modes.........................................................................................................21 5.2.2 Levinson-Durbin algorithm (all modes)......................................................................................................21
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.2.3 LP to LSP conversion (all modes)
|
..............................................................................................................22
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.2.4 LSP to LP conversion (all modes)
|
..............................................................................................................23
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.2.5 Quantization of the LSP coefficients
|
..........................................................................................................24 12.2 kbit/s mode 24 10.2, 7.95, 7.40, 6.70, 5.90, 5.15, 4.75 kbit/s modes........................................................................................................25
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.2.6 Interpolation of the LSPs
|
............................................................................................................................25 12.2 kbit/s mode 25 10.2, 7.95, 7.40, 6.70, 5.90, 5.15, 4.75 kbit/s modes........................................................................................................26 5.2.7 Monitoring resonance in the LPC spectrum (all modes).............................................................................26 5.3 Open-loop pitch analysis ..................................................................................................................................27 12.2 kbit/s mode 27 10.2 kbit/s mode 28 7.95, 7.40, 6.70, 5.90 kbit/s modes....................................................................................................................................29 5.15, 4.75 kbit/s modes......................................................................................................................................................29
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.4 Impulse response computation (all modes)
|
......................................................................................................30
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.5 Target signal computation (all modes)
|
.............................................................................................................30
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.6 Adaptive codebook
|
...........................................................................................................................................31
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.6.1 Adaptive codebook search
|
..........................................................................................................................31 12.2 kbit/s mode 31 7.95 kbit/s mode 32 10.2, 7.40 kbit/s mode .......................................................................................................................................................33 6.70, 5.90 kbit/s modes......................................................................................................................................................33 5.15, 4.75 kbit/s modes......................................................................................................................................................34 5.6.2 Adaptive codebook gain control (all modes)............................................................................................................35
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.7 Algebraic codebook
|
..........................................................................................................................................35
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.7.1 Algebraic codebook structure
|
.....................................................................................................................35 12.2 kbit/s mode 35 10.2 kbit/s mode 36 7.95, 7.40 kbit/s modes......................................................................................................................................................36 6.70 kbit/s mode 36 5.90 kbit/s mode 37 (3G TS 26.090 version 3.1.0 Release 1999) ETSI TS 126 090 V3.1.0 (2000-01) ETSI Page 4 TS 26.090 : December 1999 5.15, 4.75 kbit/s modes......................................................................................................................................................37
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.7.2 Algebraic codebook search
|
.........................................................................................................................37 12.2 kbit/s mode 39 10.2 kbit/s mode 39 7.95, 7.40 kbit/s modes......................................................................................................................................................40 6.70 kbit/s mode 40 5.90 kbit/s mode 40 5.15, 4.75 kbit/s modes......................................................................................................................................................41
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.8 Quantization of the adaptive and fixed codebook gains
|
...................................................................................41 5.8.1 Adaptive codebook gain limitation in quantization ....................................................................................41
|
027a41cea2de098957b2616ae8f22de5
|
126 090
|
5.8.2 Quantization of codebook gains
|
..................................................................................................................41 Prediction of the fixed codebook gain (all modes)............................................................................................................41 12.2 kbit/s mode 42 10.2 kbit/s mode 42 7.95 kbit/s mode 42 7.40 kbit/s mode 43 6.70 kbit/s mode 43 5.90, 5.15 kbit/s modes......................................................................................................................................................43 4.75 kbit/s mode 43 5.8.3 Update past quantized adaptive codebook gain buffer (all modes) ..........................................................................43
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.