14.1 Bad frame indication

3GPP51.010-1Mobile Station (MS) conformance specificationPart 1: Conformance specificationTS

14.1.1 Bad frame indication – TCH/FS

14.1.1.1 Bad frame indication – TCH/FS – Random RF input

14.1.1.1.1 Definition

The performance of the Bad Frame Indication (BFI) is a measure of the effectiveness of the MS under DTX conditions. It includes the effect of the 3 bit Cyclic Redundancy Check (CRC) and all other processing associated with the DTX function. The BFI is measured on a full rate speech TCH (TCH/FS) by counting the number of undetected bad frames whilst the input signal is a randomly modulated carrier.

14.1.1.1.2 Conformance requirement

On a full rate speech TCH (TCH/FS) with a random RF input, the overall reception performance shall be such that, on average, less than one undetected bad speech frame (false bad frame indication) in 60 s will be measured; 3GPP TS 05.05, subclause 6.4 b

14.1.1.1.3 Test purpose

1. To verify that the BFI performance does not exceed the conformance requirement with an allowance for the statistical significance of the test.

2. To verify that on reception of a SID frame the BFI is not set.

14.1.1.1.4 Method of test

14.1.1.1.4.1 Initial conditions

A call is set up according to the generic call set up procedure on a TCH/FS with an ARFCN in the Mid ARFCN range, power control level set to maximum power.

The SS commands the MS to complete the traffic channel loop back and signal the bad frame indication.

NOTE: DTX is used during the test to prevent the MS dropping the call.

14.1.1.1.4.2 Procedure

a) The SS simulates a BSS in DTX mode. During the period when no transmission would occur the SS transmits a GSM carrier modulated with random data at a level 11 dB above reference sensitivity level(  ). The SACCH is transmitted normally at a level 20 dB above reference sensitivity(  ). The SID frame is transmitted in its correct time interval with valid information at a level 20 dB above reference sensitivity level(  ). During transmission of SACCH or SID frames the random data is discontinued.

b) The SS transmits at least the minimum number of samples of frames of TCH/FS information and checks the BFI of the looped back signal from the MS. The SS records the number of frames where the bad frame indication is not set. During transmission by the SS of SID frames the SS checks that the BFI is not set.

NOTE 1: Further explanations on the mechanism of signalling the BFI to the SS will be found in clause 36.

NOTE 2: In some cases the MS decodes half SID frames correctly even if these are not transmitted completely. Therefore, in case that a MS detects a good SID frame, the SS has to consider the received bits in detail.

14.1.1.1.5 Test requirements

The BFI performance is accepted if the measured rate of undetected bad frames does not exceed the test limit error rate:

Test limit error rate: 0,041 %;

Minimum number of samples: 492 000 (excluding SID frames).

During loop back of SID frames no BFI shall be set.

14.1.1.2 Bad frame indication – TCH/FS – Frequency hopping and downlink DTX

14.1.1.2.1 Definition

The performance of the Bad Frame Indication (BFI) is a measure of the effectiveness of the MS under DTX conditions. It includes the effect of the 3 bit Cyclic Redundancy Check (CRC) and all other processing associated with the DTX function. The BFI is measured on a full rate speech TCH (TCH/FS) by counting the number of undetected bad frames whilst the input signal is a randomly modulated carrier.

14.1.1.2.2 Conformance requirement

On a speech TCH (TCH/FS or TCH/HS), when DTX is activated with frequency hopping through C0 where bursts comprising SID frames, SACCH frames and dummy bursts are received at a level 20 dB above the reference sensitivity level and with no transmissions at the other bursts of the TCH, the overall reception performance shall be such that, on average less than one undetected bad speech frame (false bad frame indication BFI) shall be measured in one minute for MS. 3GPP TS 05.05, subclause 6.4c.

14.1.1.2.3 Test purpose

1. To verify that the BFI performance in case of frequency hopping including the C0 radio frequency does not exceed the conformance requirement with an allowance for the statistical significance of the test.

2. To verify that on reception of a SID frame the BFI is not set.

14.1.1.2.4 Method of test

14.1.1.2.4.1 Initial conditions

A call is set up according to the generic call set up procedure on a TCH/FS with a transmitted burst 20 dB above reference sensitivity. Random frequency hopping on two channels including the C0 radio frequency with ARFCNs with at least 5 channels separation shall be used, power control level set to maximum power.

The SS commands the MS to complete the traffic channel loop back and signal the bad frame indication.

NOTE: DTX is used during the test to prevent the MS dropping the call.

14.1.1.2.4.2 Procedure

a) The SS sets downlink DTX on.

b) The SS performs the measurement over at least the minimum number of samples of frames of TCH/FS information and checks the BFI of the looped back signal from the MS. The SS only transmits SID frames, SACCH frames and dummy bursts, with no transmission of TCH bursts. The SS records the number of frames where the bad frame indication is not set. During transmission by the SS of SID frames the SS checks that the BFI is not set.

NOTE 1: Further explanations on the mechanism of signalling the BFI to the SS will be found in clause 36.

NOTE 2: In some cases the MS decodes half SID frames correctly even if these are not transmitted completely. Therefore, in case that a MS detects a good SID frame, the SS has to consider the received bits in detail.

14.1.1.2.5 Test requirements

The BFI performance is accepted if the measured rate of undetected bad frames does not exceed the test limit error rate:

Test limit error rate: 0,041 %;

Minimum number of samples: 492 000 (excluding SID frames).

During loop back of SID frames no BFI shall be set.

14.1.2 Bad frame indication – TCH/HS

14.1.2.1 Bad frame indication – TCH/HS – Random RF input

14.1.2.1.1 Definition

The performance of the Bad Frame Indication (BFI) is a measure of the effectiveness of the MS under DTX conditions. It includes the effect of the 3 bit Cyclic Redundancy Check (CRC) and all other processing associated with the DTX function. The BFI is measured on a half rate speech TCH (TCH/HS) by counting the number of undetected bad frames whilst the input signal is a randomly modulated carrier.

14.1.2.1.2 Conformance requirement

On a half rate speech TCH (TCH/HS) with a random RF input, the overall reception performance shall be such that, on average, less than one undetected bad speech frame (false bad frame indication) in 60 seconds will be measured; 3GPP TS 05.05, subclause 6.4b.

14.1.2.1.3 Test purpose

1. To verify that the BFI performance does not exceed the conformance requirement with an allowance for the statistical significance of the test.

2. To verify that on reception of a SID frame the BFI is not set.

14.1.2.1.4 Method of test

14.1.2.1.4.1 Initial conditions

A call is set up according to the generic call set up procedure on a TCH/HS with an ARFCN in the Mid ARFCN range, power control level set to maximum power.

The SS commands the MS to complete traffic channel loop back A and signal frames detected with BFI=1 as erased.

NOTE 1: Test loop A is defined in clause 36. Frames detected with BFI=1 are signalled as erased on the uplink.

NOTE 2: DTX is used during the test to prevent the MS dropping the call.

14.1.2.1.4.2 Procedure

a) The SS simulates a BSS in DTX mode. During the periods when no transmission would occur, the SS transmits a GSM carrier modulated with random data, at a level 11 dB above reference sensitivity level(  ). The SACCH is transmitted normally, at a level 20 dB above reference sensitivity(  ). The SID frame is transmitted in its correct time interval, with valid information, at a level 20 dB above reference sensitivity level(  ). During transmission of SACCH or SID frames, the random data is discontinued.

b) The SS transmits at least the minimum number of samples of frames of TCH/HS information and checks the BFI of the looped back signal from the MS. The SS records the number of frames where the bad frame indication is not set. During transmission by the SS of SID frames the SS checks that the BFI is not set.

14.1.2.1.5 Test requirements

The BFI performance is accepted if the measured rate of undetected bad frames does not exceed the test limit error rate:

Test limit error rate: 0,041 %;

Minimum number of samples: 492 000 (excluding SID frames).

During loop back of SID frames no BFI shall be set.

14.1.2.2 Bad frame indication – TCH/HS – Frequency hopping and downlink DTX

14.1.2.2.1 Definition

The performance of the Bad Frame Indication (BFI) is a measure of the effectiveness of the MS under DTX conditions. It includes the effect of the 3 bit Cyclic Redundancy Check (CRC) and all other processing associated with the DTX function. The BFI is measured on a half rate speech TCH (TCH/HS) by counting the number of undetected bad frames whilst the input signal is a randomly modulated carrier.

14.1.2.2.2 Conformance requirement

On a half rate speech TCH (TCH/HS), when DTX is activated with frequency hopping through C0 where bursts comprising SID frames, SACCH frames and dummy bursts are received at a level 20 dB above the reference sensitivity level and with no transmissions at the other bursts of the TCH, the overall reception performance shall be such that, on average less than one undetected bad speech frame (false bad frame indication BFI) shall be measured in one minute for MS. 3GPP TS 05.05, subclause 6.4c.

14.1.2.2.3 Test purpose

1. To verify that the BFI performance in case of frequency hopping including the C0 radio frequency does not exceed the conformance requirement with an allowance for the statistical significance of the test.

2. To verify that on reception of a SID frame the BFI is not set.

14.1.2.2.4 Method of test

14.1.2.2.4.1 Initial conditions

A call is set up according to the generic call set up procedure on a TCH/HS with a transmitted burst 20 dB above reference sensitivity. Random frequency hopping on two channels including the C0 radio frequency with ARFCNs with at least 5 channels separation shall be used, power control level set to maximum power.

The SS commands the MS to complete the traffic channel loop back and signal the bad frame indication.

NOTE: DTX is used during the test to prevent the MS dropping the call.

14.1.2.2.4.2 Procedure

a) The SS sets downlink DTX on.

b) The SS performs the measurement over at least the minimum number of samples of frames of TCH/HS information and checks the BFI of the looped back signal from the MS. The SS only transmits SID frames, SACCH frames and dummy bursts, with no transmission of TCH bursts. The SS records the number of frames where the bad frame indication is not set. During transmission by the SS of SID frames the SS checks that the BFI is not set.

NOTE 1: Further explanations on the mechanism of signalling the BFI to the SS will be found in clause 36.

NOTE 2: In some cases the MS decodes half SID frames correctly even if these are not transmitted completely. Therefore, in case that a MS detects a good SID frame, the SS has to consider the received bits in detail.

14.1.2.2.5 Test requirements

The BFI performance is accepted if the measured rate of undetected bad frames does not exceed the test limit error rate:

Test limit error rate: 0,041 %;

Minimum number of samples: 492 000 (excluding SID frames).

During loop back of SID frames no BFI shall be set.

14.1.3 Void

14.1.4 Void

14.1.5 Bad frame indication – TCH/AFS (Speech frame)

14.1.5.1 Bad frame indication – TCH/AFS – Random RF input

14.1.5.1.1 Definition

The performance of the Bad Frame Indication (BFI) is a measure of the effectiveness of the MS. It includes the effect of the 6 bits Cyclic Redundancy Check (CRC). The BFI is measured on a full rate speech TCH (TCH/AFS) by counting the number of undetected bad frames whilst the input signal is a randomly modulated carrier.

14.1.5.1.2 Conformance requirement

On a full rate speech TCH (TCH/AFS) with a random RF input, the overall reception performance shall be such that, on average, less than one undetected bad speech frame (false bad frame indication) in 60 s will be measured, meaning a rate of 0.0333% of undetected bad speech frames; 3GPP TS 05.05, subclause 6.4b.

14.1.5.1.3 Test purpose

1. To verify that the BFI performance does not exceed the conformance requirement with an allowance for the statistical significance of the test.

14.1.5.1.4 Method of test

14.1.5.1.4.1 Initial conditions

A call is set up according to the generic call set up procedure on a TCH/AFS with an ARFCN in the Mid ARFCN range, power control level set to maximum power. The active codec set (ACS) shall consist of one codec mode as AFS 12.2.

The SS commands the MS to complete the traffic channel loop back and signal the bad frame indication.

14.1.5.1.4.2 Procedure

a) The SS simulates a BSS with downlink DTX disabled. During the period when traffic frames would occur the SS transmits a GSM carrier modulated with random data at a level 11 dB above reference sensitivity level. The SACCH is transmitted normally at a level 20 dB above reference sensitivity. During transmission of SACCH or frames the random data is discontinued.

b) The SS transmits at least the minimum number of samples of frames of TCH/AFS information and checks the BFI of the looped back signal from the MS. The SS records the number of frames where the bad frame indication is not set

NOTE 1: Further explanations on the mechanism of signalling the BFI to the SS will be found in clause 36.

Maximum/Minimum Duration of Test

Statistical test method

Maximum: 280 minutes (GSM 700, T-GSM 810, GSM850, GSM900, DCS1800, PCS1900).

Minimum: 7 minutes (GSM 700, T-GSM 810, GSM850, GSM900, DCS1800, PCS1900).

Non-statistical test method

Maximum/minimum: 164 minutes (GSM 700, T-GSM 810, GSM850, GSM900, DCS1800, PCS1900).

14.1.5.1.5 Test requirements

Testing the Bad Frame Indication (BFI) performance can be done either in the classical way with a fixed minimum number of samples or using statistical methods that lead to an early pass/fail decision with test time significantly reduced for MS with (BFI) performance not on the limit.

Both methods are based on a bad DUT factor M = 1.5.

14.1.5.1.5.1 Statistical testing of BFI performance with early decision

For more information on statistical testing of BFI performance, especially the definition of limit lines refer to Annex 6.2

Wrong decision risk F for one single error rate test:

Fpass   =   Ffail   =   F and F   =   0.2%

Wrong decision probability D per test step:

Dpass   =   Dfail   =   D and D   =   0.0085%

Parameters for limit lines:

1. D =  0.000085 wrong decision probability per test step.

2. M =   1.5 bad DUT factor

3. ne number of (error) events. This parameter is the x‑ordinate in figure 14‑1.

4. ns number of samples. The error rate is calculated from ne and ns.

Limit checking

For an early decision a minimum number of (error) events is necessary.

For an early pass decision ne   ≥   1 (inclusive artificial error)

For an early fail decision ne   ≥   7

When the target test time has been reached the test is finished and a pass/fail decision can be made.

Table 14-4a: Statistical test limits for BFI performance

BFI TCH/AFS

Orig. BFI

Derived

Target number

Target test

Target test time

Channel

bits per sec

frames per s

requirement

test limit

of samples

time (s)

(hh:mm:ss)

AFS 12.2

frames

12200

50

0,000333

0,000411

839575

16792

04:39:52

14.1.5.1.5.2 Fixed testing of BFI performance with minimum number of samples

The BFI performance is accepted if the measured rate of undetected bad frames does not exceed the test limit error rate:

Test limit error rate: 0,041 %;

Minimum number of samples: 492 000

14.1.6 Bad frame indication – TCH/AHS

14.1.6.1 Bad frame indication – TCH/AHS – Random RF input

14.1.6.1.1 Definition

The performance of the Bad Frame Indication (BFI) is a measure of the effectiveness of the MS. It includes the effect of the 6-bit Cyclic Redundancy Check (CRC). The BFI is measured on a half rate speech TCH (TCH/AHS) by counting the number of undetected bad frames whilst the input signal is a randomly modulated carrier.

14.1.6.1.2 Conformance requirement

On a half rate speech TCH (TCH/AHS) with a random RF input, the overall reception performance shall be such that, on average, less than one undetected bad speech frame (false bad frame indication) in 60 s will be measured, meaning a rate of 0.0333% of undetected bad speech frames; 3GPP TS 05.05, subclause 6.4b.

14.1.6.1.3 Test purpose

1. To verify that the BFI performance does not exceed the conformance requirement with an allowance for the statistical significance of the test.

14.1.6.1.4 Method of test

14.1.6.1.4.1 Initial conditions

A call is set up according to the generic call set up procedure on a TCH/AHS with an ARFCN in the Mid ARFCN range, power control level set to maximum power. The active codec set (ACS) shall consist of one codec mode as AHS 7.95.

14.1.6.1.4.2 Procedure

a) The SS simulates a BSS with downlink DTX disabled. During the periods when traffic frames would occur, the SS transmits a GSM carrier modulated with random data, at a level 11 dB above reference sensitivity level. The SACCH is transmitted normally, at a level 20 dB above reference sensitivity. During transmission of SACCH frames, the random data is discontinued.

b) The SS transmits at least the minimum number of samples of frames of TCH/AHS information and checks the BFI of the looped back signal from the MS. The SS records the number of frames where the bad frame indication is not set.

Statistical test method

Maximum: 280 minutes (GSM 700, T-GSM 810, GSM850, GSM900, DCS1800, PCS1900).

Minimum: 7 minutes (GSM 700, T-GSM 810, GSM850, GSM900, DCS1800, PCS1900).

Non-statistical test method

Maximum/minimum: 164 minutes (GSM 700, T-GSM 810, GSM850, GSM900, DCS1800, PCS1900).

14.1.6.1.5 Test requirements

Testing the Bad Frame Indication (BFI) performance can be done either in the classical way with a fixed minimum number of samples or using statistical methods that lead to an early pass/fail decision with test time significantly reduced for MS with (BFI) performance not on the limit.

Both methods are based on a bad DUT factor M = 1.5.

14.1.6.1.5.1 Statistical testing of BFI performance with early decision

For more information on statistical testing of BFI performance, especially the definition of the limit lines refer to Annex 6.2

Wrong decision risk F for one single error rate test:

Fpass   =   Ffail   =   F and F   =   0.2%

Wrong decision probability D per test step:

Dpass   =   Dfail   =   D and D   =   0.0085%

Parameters for limit lines:

1. D =  0.000085 wrong decision probability per test step.

2. M =   1.5 bad DUT factor

3. ne number of (error) events. This parameter is the x‑ordinate in figure 14‑1.

4. ns number of samples. The error rate is calculated from ne and ns.

Limit checking

For an early decision a minimum number of (error) events is necessary.

For an early pass decision ne   ≥   1 (inclusive artificial error)

For an early fail decision ne   ≥   7

When the target test time has been reached the test is finished and a pass/fail decision can be made.

Table 14-4b: Statistical test limits for BFI performance

BFI TCH/AHS

Orig. BFI

Derived

Target number

Target test

Target test time

Channel

bits per sec

frames per s

requirement

test limit

of samples

time (s)

(hh:mm:ss)

AHS 7.95

frames

7950

50

0,000333

0,000411

839575

16792

04:39:52

14.1.6.1.5.2 Fixed testing of BFI performance with minimum number of samples

The BFI performance is accepted if the measured rate of undetected bad frames does not exceed the test limit error rate:

Test limit error rate: 0,041 %;

Minimum number of samples: 492 000.

14.1.7 Void