EFRC

Wireless Networks

Enhanced Full-Rate Coder (EFRC)

Quick Reference Guidelines

MTX06 Preliminary 01.03 March 1998

PRELIMINARY

411-2131-910

Wireless Networks

Enhanced Full-Rate Coder (EFRC)

Quick Reference Guidelines

Product release: MTX06Document release: Preliminary 01.03Date: March 1998Document Number: 411-2131-910

Copyright Country of printing Confidentiality Legal statements Trademarks

1998 Northern Telecom

Printed in Canada

NORTHERN TELECOM CONFIDENTIAL:

The information contained in this document is the property of Northern Telecom. Except as specifically authorized in writing by Northern Telecom, the holder of this document shall keep the information contained herein confidential and shall protect same in whole or in part from disclosure and dissemination to third parties and use same for evaluation, operation, and maintenance purposes only.

Information is subject to change without notice.

DMS, DMS SuperNode, DMS-MSC, DMS-HLR, DMS-100, and MAP are trademarks of Northern Telecom.

iv

411-2131-910 Preliminary 01.03 March 1998

v

Wireless Networks EFRC Quick Reference Guidelines MTX06

Publication history

March 1998

Preliminary version 01.03.

vi


vii


Contents

About this document ix

Purpose ixAudience ix

Enhanced Full Rate Codec (EFRC) 1-1

Purpose and feature description 1-1Functionality 1-1

Implementation requirements 1-3Software 1-3Hardware 1-3

Table datafill 1-5Table DSPMINV 1-5Table VCHINV 1-7Table LCRINV 1-9Table CHNLSET 1-9

Implementation recommendations 1-10Datafill 1-10

Performance monitoring and optimization 1-11Feature interaction 1-11

viii

Contents


ix


1

About this document

Purpose

This document is one in a series of Quick Reference Guidelines developed to familiarize customers with new and evolving DMS-MTX features.

References are made throughout this document to Northern Telecom Publications (NTPs). Assistance is also available directly from Nortel Wireless Product Support.

Audience

This publication is intended for system engineers and network planners responsible for establishing and monitoring cellular systems.

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x

About this document


1

1-1

Wireless Networks Enhanced Full Rate Coder (EFRC) Quick Reference Guidelines

1

Enhanced Full Rate Codec (EFRC)

Purpose and feature description

The Enhanced Full Rate Codec (EFRC) has been integrated into the MTX06 software stream to provide improved voice quality and greater resistance to channel impairments. This section provides recommendations for deployment and application of the EFRC.

Note:

Further details can be found in

DMS-MTX Digital Intelligent Cellular Peripheral Technical Description

, 411-2131-127, and

TDMA Deployment Guidelines

, 411-2131-001.

The IS-641 EFRC delivers improved speech quality by substituting a contemporary voice codec for the Vector Sum Excited Linear Prediction (VSELP) codec originally introduced with TDMA digital cellular. The bit rate of the EFRC is nominally 8 kbps, as with VSELP. This fact allows it to be included into existing TDMA systems with little impact to existing installations.

The EFRC codec does not change the TDMA slot structure and as such does not alter the RF footprint between VSELP and EFRC. However, the codec provides both improved voice quality via contemporary speech coding algorithms, and greater resistance to channel interference by allocating more bits to error correction. Mean Opinion Score (MOS) comparison studies have shown that the EFRC usually outscores the VSELP codec under identical test conditions.

Functionality

EFRC provides a number of capabilities, described below.

Handoff

The transition matrix in Table 1-1 outlines the EFRC and VSELP handoff (inter, intra, and handover) capabilities supported by MTX06. Note that

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mixed digital handoffs (VSELP to EFRC and vice versa) are not currently supported and will result in cell dragging and dropped calls.

Codec bypass

Multiple coding and decoding of speech data (tandeming) results in poor voice quality. The greatest risk of tandem effects occurs on a mobile-to-mobile call where the call setup includes mobile-to-land and then land-to-mobile, resulting in an unnecessary coding/decoding stage.

A mobile-to-mobile EFRC Codec Bypass is implemented in the EDSPM, provided both modules are linked on the switch side. During a mobile-to-mobile call, this feature automatically switches the call setup from tandemed EFRC encoding/decoding processes to a single EFRC encoding/decoding stage between the mobiles.

Mobile Echo Control (MEC)

Implementation of the EFRC speech coder includes Mobile Echo Control (MEC) functionality in the EDSPM load (EFRE6AU3). MEC was designed to overcome acoustic echo generated by mobile terminals, particularly those operating in handsfree mode. If echo is detected, MEC supresses it and injects “comfort noise” in its place..

• Functionality is controlled via Office Parm (MTX_MOBILE_ECHO_NOISE) in Table OFCENG

• MEC parm (MOBILE_ECHO_CONTROL) turns on/off MEC capability in real-time

• CNG parm (COMFORT_NOISE_GENERATION) turns on/off CNG, which provides a background “comfort noise” when the MEC activates.

ACCH support

EFRC is supported on analog control channels (ACCH). Since the bit rate of EFRC (with channel coding) is the same as for VSELP, the TDMA slot structure defined in IS-54B and IS-136 is maintained.

Table 1-1Handoff capabilities

Target cell/sector

Serving Cell/Sector

EFRC VSELP Analog

EFRC

Supported Not Supported Supported

VSELP

Not Supported Supported Supported


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Implementation requirements

Software

EFRC functionality resides in the standard MTX06 software releases, as noted in Table 1-2.

Hardware

EFRC requires the installation of the EDSPM (Enhanced DSPM) platform.

Note that subscribers require EFRC-capable mobiles in order to have access to EFRC service. However, the EDSPM can be configured to handle both VSELP and EFRC-based mobiles. The EDSPM is capable of dynamically switching between VSELP and EFRC service on a per-call basis provided it is configured as VSELP_EFRC mode (further details in "Table datafill").

Call capacity

Call capacity of the speech and data coder card will vary depending on how it is deployed:

• In VSELP mode, an NTEX93AA card can support up to 24 calls.

• In VSELP_EFRC or EFRC mode, the NTEX93AA card can support up to 12 calls.

This is a consequence of the increased computational requirements to implement the EFRC algorithm. As outlined in Table 1-3, EDSPM call capacity depends on the configured voice coding service (VSELP, EFRC, or VSELP_EFRC) and DS30A usage.

Table 1-2Software loads

Description Hardware (PEC) Load name

DSPM Enhanced (VSELP/EFRC)

NTEX93AA EFRE6AU3

Table 1-3EDSPM call capacity

Configuration Service DS30A usage Calls DRUs

1 x NTEX93AA VSELP 1 link/30 channels 21 7

1 x NTEX93AA VSELP 2 links /36 channels 24 8

2 x NTEX93AA VSELP 2 links /64 channels 45 15

1 x NTEX93AA EFRC 1 link /18 channels 12 4

2 x NTEX93AA EFRC 1 link /30 channels 21 7

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0

The EFRC requires an EDSPM hardware platform to be installed and fully functional. The EDSPM hardware platform consists of the following:

• DSP Control Processor (DSCP) card(1 card per module)

NTAX80AB

• Digital Speech and Data Coder (DSDC) cards(1 to 4 cards per module)

NTEX93AA

• Enhanced DSP Module shelf

NTAX7604

• Digital Signal Bus Terminator (DSBT) card

NTEX90AA

The NTEX93AA operating in VSELP mode provides high call capacity. Two cards support 45 calls on 15 DRUs and require the full capacity of two DS30A links.

All NTEX93AA cards associated with a given EDSPM are required to be configured with the same service mode. For example, EDSPM

nn

will have all 4 of its NTEX93AA cards configured as either VSELP, EFRC, or VSELP_EFRC.

2 x NTEX93AA EFRC 2 links /36 channels 24 8



1 x NTEX93AA VSELP_EFRC 1 link /18 channels 12 4

2 x NTEX93AA VSELP_EFRC 2 links /30 channels 21 7




Table 1-3EDSPM call capacity

Configuration Service DS30A usage Calls DRUs


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Table datafill

The following datafill tables are required to deploy EFRC. Note that this is not an exhaustive list and that other datafill tables may be required to provide background datafill.

Note:

For a detailed listing of datafill tables, refer to

DMS-MTX Customer Data Schema Reference Manual

, Vols. 1 & 2, 411-2131-451.

• Table DSPMINV

• Table CHNLSET

• Table LCRINV

• Table VCHINV

Current tables have been extended to contain new data, implement cross-checking within and among tables, and format the static data tuples to convey the new data to peripheral processors.

Table DSPMINV

This table stores a tuple of data associated with each EDSPM describing its configuration, including the type of processor card, speech and data coder card, and the associated service mode.

Prior development in MTX03 added the capability to specify the voice coding service provided by the individual DSP groups. This voice coding service was designated as TDMA3. TDMA3 service is based on the Vector Sum Excited Linear Prediction (VSELP) coding model. The introduction of EFRC requires an extension to the DSPMINV data table to explicitly specify the voice coding service provided, since both VSELP and EFRC qualify as TDMA3 voice coding services.

This subsection details the changes to the two fields of table DSPMINV required to support EFRC functionality. All other existing fields of table DSPMINV remain unchanged.

Field DSDCPECS

The DSDCPECS field is a vector of up to 4 entries, each of which describes the presence of one voice codec card. The "service" field of each DSDC PEC is extended to allow the values "EFRC" and "VSELP_EFRC." These values assign a circuit pack to EFRC voice coding service, or allow it to switch between EFRC and VSELP service respectively. In addition, the field "TDMA3" is renamed to "VSELP" to distinguish between VSELP and EFRC codecs, both of which qualify as TDMA3 service.

(0-3

EX93AA

/AX81AA VSELP/

EFRC

/

VSELP_EFRC

)

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Figure 1-1DSPM/EDSPM DSDC cards

Field DSCPPEC

The DSCPPEC field identifies the DSPM/EDSPM Control Processor. This field is extended to allow the value "AX80AB" which represents the new EDSPM processor required to implement EFRC functionally. The DSCPPEC field is checked with the "service" field of each DSDC PEC to ensure compatibility. The DSCPPEC field value of "AX80AB" is required for EFRC voice coding service and may also be used for VSELP service. The value "AX80AA" is limited to VSELP service.

Figure 1-2 shows the new DSCPPEC "service" field values.

AX80AA/

AX80AB

2X70AF

AX80AA

AX80AB

AX80AB

AX80AA

EX93AA

--EX93AA

EX93AA

EX93AA

EX93AA

EX93AA

EX93AA

EX93AA

EX93AA

EX93AA

AX81AA

AX81AA

AX81AA

AX81AA

0X50AA

2X70AF

EDSPM 2 DSPM 3

0 - 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 - 28

0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3

EDSPM 0 EDSPM 1

(0 EX93AA EFRC) (1 EX93AA EFRC) (2 EX93AA EFRC) (3 EX93AA EFRC)$


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Figure 1-2DSPMINV table tuple

Table VCHINV

This table contains voice channel-specific information. The table specifies the frequency, trunk member, and port to which the voice channel radio is assigned. With respect to this feature, this table specifies the service mode of the radio (VSELP, EFRC, or VSELP_EFRC). The VSELP_EFRC mode allows the radio to dynamically switch to the service mode requested by the mobile.

The changes to Table Voice Channel Inventory (VCHINV) provide extensions of the services provided by a particular voice channel. Previous releases supported voice channel service types of ANALOG (AMPS analog), TDMA3, ANALOG_TDMA3, and ANALOG_CDPD. As with table DSPMINV the names of two of these voice coding services are changed to VSELP (from TDMA3), and ANALOG_VSELP (from ANALOG_TDMA3).

Additionally, the service type set is extended to include the following:

• EFRC - The voice channel is dedicated to EFRC digital service using only the enhanced codec.

• VSELP_EFRC - The voice channel is dedicated to digital service but may use either VSELP or EFRC codecs.

• ANALOG_VSELP_EFRC - The voice channel may float among AMPS analog, digital VSELP, and digital EFRC service on a demand basis.

DSPMKEY FRTYPE FRNO SHPOS FLOOR ROW FRPOS SHPEC DSCPSLOT DSCPPEC LOAD

PORTS DSDCPECS

--------------------------------------------------------------------------------------------------------------------------------------------

0 0 DICP 0 0 4 AA 4 AX7604 4 AX80AA DSMX6BP

(0) (2) $ (0 EX93AA VSELP) (1 EX93AA VSELP) $

0 1 DICP 0 1 4 AA 4 AX7604 9 AX80AB EDSX6BP

(1) (3) $ (0 EX93AA EFRC) (1 EX93AA EFRC) (2 EX93AA EFRC) (3 EX93AA EFRC) $

0 2 MDSP 1 0 4 AA 4 AX7604 15 AX80AB EDSX6BP(4) (6) $ (0 EX93AA VSELP_EFRC) (1 EX93AA VSELP_EFRC) (2 EX93AA VSELP_EFRC) $

0 3 DEXT 2 0 4 AA 4 AX7604 20 AX80AA DSMX6BP

(5) (7) $ (0 AX81AA VSELP) (1 AX81AA VSELP) (2 AX81AA VSELP) (3 AX81AA VSELP) $

1 0 DEXT 2 1 2 AA 2 AX7601 4 AX80AB EDSX6BP(9) (11) $ (0 AX81AA VSELP) (1 AX81AA VSELP) (2 AX81AA VSELP) (3 AX81AA VSELP) $

REXTST REXHOUR REXMIN

Y 6 0

N

Y 3 30

N

Y 1 0

Note: The DSPMINV fields (REXTST, REXHOUR, REXMIN) are part of theIntegrated TDMA Diagnostics and are included in MTX06 release.

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When datafilling voice channels in table VCHINV the associated DSP group (assigned in table DSPMINV) must have a service type that is compatible with the service type of the voice channel.

Table 1-4 shows the compatible service types between the VCHINV and DSPMINV tables.

This subsection details the changes to the field ADMODE of table VCHINV required to support EFRC functionality.

Field MODE

The field MODE describes the voice channel mode of operation. The service type of each voice channel in table VCHINV is extended to allow the values "EFRC", "VSELP_EFRC", and "ANALOG_VSELP_EFRC.”

The value "EFRC" assigns a voice channel to EFRC service. The value "VSELP_EFRC" allows the voice channel to switch between VSELP and EFRC service. The value "ANALOG_VSELP_EFRC" allows the voice channel to switch among ANALOG, VSELP, or EFRC service.

In addition, the service types "ANALOG_TDMA3" and "TDMA3" are renamed "ANALOG_VSELP" and "VSELP" respectively. See Figure 1-3 for an example of the VCHINV table tuple with the new service types.

Table 1-4Compatible VCHINV and DSPMINV service types

VCHINV service types Compatible DSPMINV service types

EFRC EFRC, VSELP_EFRC

VSELP VSELP, VSELP_EFRC

VSELP_EFRC VSELP_EFRC

ANALOG Not applicable

ANALOG_VSELP_EFRC VSELP_EFRC

ANALOG_VSELP VSELP, VSELP_EFRC

ANALOG_CDPD Not applicable


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Figure 1-3VCHINV table tuple

0

Table LCRINV

The functionality of LCRINV does not change for EFRC; however, for MTX06, the ADMODE field of Table LCRINV is renamed to LRMODE, with values of TDMA and ANALOG. This is to prevent confusion with the ADMODE field of Table VCHINV. The locating receiver is not concerned with the type of voice coding algorithm (VSELP or EFRC); therefore, only TDMA is used to represent the digital LR MODE.

Table CHNLSET

This table contains the available channel modes (VSELP, EFRC, or VSELP_EFRC), interference probabilities (LPI or MPI), and the selection sequence (MIDL or ASEQ). The resource allocation of each channel mode depends upon the selection sequence (MIDL or ASEQ) and is independent. For instance, VSELP channels may be datafilled as MIDL whereas VSELP_EFRC channels in the same cell may be datafilled as ASEQ. In terms of resource allocation, priority is given to VSELP and EFRC queues respectively and only when these queues have been exhausted by VSELP or EFRC requests will the channels in the VSELP_EFRC queue begin to be allocated.

VCHKEY CHAN_DATA MODE GROUP

TRKMEMS TERMATTR CARD PORT ALARMPT XCVRSAT DCCHBKUP ------------------------------------------------------------------------------------------------------------------------------------------- 20X 0 46 VSELP_EFRC (2 0 3) $ 1 ( 0 ) ( 100 ) ( 200) $ TRU1_02 0 2 61 DEFAULT N

20X 1 67 ANALOG_VSELP (3 0 1) $ 2 ( 1 ) ( 101 ) ( 201) $ TRU1_02 0 3 61 DEFAULT N

20X 2 504 ANALOG 0 ( 5) $ TRU_02 0 4 61 DEFAULT N

20X 3 110 EFRC ( 0 0 1) $ 3 ( 2 ) (102 ) ( 202) $ TRU1_02 0 5 61 DEFAULT N

20X 4 131 ANALOG_VSELP_EFRC ( 0 1 0) $ 4 ( 3 ) (103 ) ( 203) $ TRU1_02 0 6 61 DEFAULT N

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Implementation recommendations

Datafill

The following lists describe table field validation checks:

Table DSPMINV

Validation of fields DSPMKEY, FRTYPE, FRNO, SHPOS, FLOOR, ROW, FRPOS, SHPEC, DSCPSLOT, LOAD, and PORTS continue unchanged from previous releases.

The "service" field of DSDCPECS may be datafilled EFRC, VSELP, or VSELP_EFRC.

Restrictions relating to the DSDCPECS field:

• The "service" field must be the same for all DSP groups of a DSPM/EDSPM.

• EFRC and VSELP_EFRC services require the NTEX93AA codec card.

Field DSCPPEC may be datafilled either AX80AA or AX80AB.

Restrictions relating to the DSCPPEC field

• The AX80AB is required for EFRC and VSELP_EFRC service.

• The AX80AA supports only VSELP voice coding service.

• The AX80AB can be datafilled on AX7601 and AX7604 shelves. However, only VSELP voice coding is available on AX7601 shelves.

The DSPM/EDSPM does NOT need to be off-line (OFFL) before changing the DSCP PEC as was the case with earlier MTX releases.

Table VCHINV

Checking for fields VCHKEY, CHAN_DATA, GROUP, TRKMEMS, TERMATTR, CARD, PORT, ALARMPT, and XCVRSAT continue unchanged from previous releases.

The field MODE:

• can be datafilled as ANALOG, ANALOG_VSELP, ANALOG_VSELP_EFRC, ANALOG_CDPD, EFRC, VSELP, or VSELP_EFRC.

• a corresponding entry for the MODE type must be present in Table CHNLSET. CHNLSET is a new MTX06 table.

• restrictions relating to the DSPM_INFO field: if the user selects the DSP group for the voice channel, the DSP group must supply the voice coding service required by the voice channel. For example, an ANALOG_VSELP voice channel must select a DSP group supplying either VSELP or VSELP_EFRC voice coding.


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Performance monitoring and optimization

Two new OM groups provide information on EFRC channel requests as well as VSELP and analog channel requests. The two OM groups are:

• LPICHUSG (Low Probability of Interference Channel Usage)

• MPICHUSG (Moderate Probability of Interference Channel Usage)

These groups provide resource management data for calls allocated to low probability of interference (LPI) and moderate probability of interference (MPI) voice channels.

Within these groups are two OMs of interest:

— LPEFNONE -

The number of requests for a LPI EFRC digital voice channel which were not filled.

— MPEFNONE -

The number of requests for a MPI EFRC digital voice channel which were not filled

These simply peg when a request for an EFRC digital voice channel is not allocated any channel compatible to the mobile. These OMs may be used to determine where EFRC channels are required.

Feature interaction

The required NTAX80AB EFRC Controller Pack, which replaces the NTAX80AA Controller, is backward-compatible to MTX04 DSPM/EDSPM shelf assemblies.

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Wireless Networks

Enhanced Full-Rate Codec (EFRC)Quick Reference Guidelines

Wireless Customer Documentation, ManagerNorthern Telecom2924 11St. NECalgary, AB T2E 7L7Phone: (403) 781-5106 / Fax: (403) 232-4083http://www.Nortel.com/wireless/docutrain/email.html

1998 Northern Telecom

Northern Telecom Ltd., all rights reserved

NORTHERN TELECOM CONFIDENTIAL: The information contained in this document is the property of Northern Telecom. Except as specifically authorized in writing by Northern Telecom, the holder of this document shall keep the information contained herein confidential and shall protect same in whole or in part from disclosure and dissemination to third parties and use same for evaluation, operation, and maintenance purposes only.

Information is subject to change without notice. DMS, DMS SuperNode, DMS-MSC, DMS-HLR, DMS-100, and MAP are trademarks of Northern Telecom.Publication number: 411-2131-910Product release : ReleaseDocument version: 01.03Date: March 1998Printed in Canada

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