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the necessary security measures associated with handling the

authentication keys and algorithms.

QQ88..1100::

How can I test a TETRA mobile that uses mutual authen-

tication?

AA88..1100::

Mutual authentication involves the mobile authenticating

the network as well as the network authenticating the mobile. This

functionality is specified for TIPv5, and is always initiated by the

TETRA network. There is currently no TIP specification for a TETRA

mobile to initiate authentication of the network when the network

has not authenticated the mobile. The IFR 2968 system informa-

tion indicates that authentication is not supported, hence a TETRA

mobile should not expect to be authenticated by the IFR 2968,

and should not expect to authenticate the IFR 2968.

QQ88..1111::

Will the IFR 2968 support mutual authentication in a

future upgrade?

AA88..1111::

No, this would be a breach of TETRA security. The pur-

pose of mutual authentication is for TETRA mobiles to be sure that

they are communicating with a real TETRA base station and not a

spoof base station intercepting their calls. It is therefore important

that the algorithms and keys for mutual authentication are only

released to genuine TETRA networks and are not implemented in

a radio test set.

QQ88..1122::

Could the IFR 2968 test the authentication process with-

out involving secure algorithms and keys in a future upgrade?

AA88..1122::

This is a possibility, although currently IFR has no plans to

implement this functionality. This process is supported in GSM

testing through the use of a standard simple authentication algo-

rithm for test purposes (XOR challenge with internal key) and

through the use of standard Test SIMs incorporating the test algo-

rithm and a known test key. Hence GSM test sets send an authen-

tication challenge to a mobile and know what response to expect,

without involving any breach of the secure algorithms and keys

used on real networks.

Currently, TETRA mobiles do not use SIMs, there is no definition

for a TETRA Test SIM, and no standard simple algorithm or known

key for test purposes. Therefore such a test would be of limited

value since the IFR 2968 would not know what response to

expect.

Section 9 Q&A: Miscellaneous functions

QQ99..11::

Can the IFR 2968 test TETRA mobiles off-air?

AA99..11::

Yes, but this should only be used as a last resort for func-

tional testing if you are unable to achieve a direct RF connection

between the mobile and the test set. Transmitter power and

receiver sensitivity levels will be uncalibrated, and there are asso-

ciated problems of the mobile receiving real base station signals

and generating unauthorised transmissions. Refer to 'RF connec-

tion between the mobile and the IFR 2968' in the IFR application

note 'Testing TETRA mobiles with the IFR 2968' for details.

QQ99..22::

Can the IFR 2968 receive TETRA base station signals off-

air?

AA99..22::

Yes, when in reasonably close proximity, typically no more

than 3 km line of sight and with a signal level not less than -75

dBm. For details of how to do this refer to 'Off-Air Base Station test-

ing' in the 2968 Phase 3.2 supplement issue 10, chapter 5, page

QQ99..33::

Can the IFR 2968 perform off-air BER testing (coverage

monitoring or drive testing)?

AA99..33::

No. The IFR 2968 does not have the sensitivity or selectiv-

ity to perform off-air coverage monitoring. It can receive off-air

base station signals in close proximity to a base station, e.g. 3 km

line of sight, and can decode the base station signals down to a

level of approx. -75 dBm. Below this level the spectrum analyser

is still usable, but will not be as good as a dedicated off-air cover-

age monitor. It may be possible to improve this with an external

RF amplifier and filters. The IFR 2968 is designed for measuring

strong signals either directly connected or in close proximity off-

air, hence it does not have the ability to receive weak signals in

fringe coverage areas subject to multipath fading and interfer-

ence.

There are other specialist test and measurement companies who

do have coverage analysis products, a selection of which are list-

ed below:

Actix www.actix.com

Rotadata www.rotadata.com

Nemo Technologies www.nemotechnologies.com

ATDI www.atdi.co.uk

The above is not necessarily a complete list.

QQ99..44::

Can the IFR 2968 test other base station components

besides the transceiver?

AA99..44::

Yes. You can measure the different cables, couplers, filters,

duplexers and amplifiers using the spectrum analyser function

with its tracking generator. Individual losses can be easily meas-

ured within their frequency range. The tracking generator, when

used with a directional coupler or a reflection bridge, will allow

you to quickly check the antenna return loss. To use the tracking

generator you need to de-select TETRA and select RF TEST mode

as follows: [SYSTEMS] [SYSTEM] [no system] [RF TEST] [RF

IN/OUT]. Set the RF GEN LEVEL as required, then select [spec

ana] [expand ON off] [track ON off]. Set reference level, reference

frequency and span/div as required. For further details, refer to the

IFR 2965A/ 2966A/2967/2968 Operating Manual 46882/274.

The internal digital multimeter can be used to measure the volt-

age of both AC mains and DC power supply. AC / DC current,

resistance and continuity tests can also be performed. You can

use the multimeter with or without TETRA selected. Press [AF

TEST] [MULTI METER] to access these functions. For further

details, refer to the IFR 2965A/2966A/2967/2968 Operating

Manual 46882/274.

QQ99..55::

Can I store and recall different TETRA system set-ups on

the IFR 2968?

AA99..55::

Yes, using a memory card. You can store system set-up

information, user defined autotest programs, autotest results and

screen dump images onto named stores on a memory card.

Refer to the IFR 2968 Phase 3.2 TETRA supplement issue 10,

chapter 10, for details.

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