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QQ66..55::

The essential network parameters have been set correctly

but the mobile still does not register to the IFR 2968. Is there any-

thing else that needs to be checked?

AA66..55::

Refer to 'Annex C: Troubleshooting when a mobile does not

the IFR 2968' for further assistance.

QQ66..66::

The mobile registers to the IFR 2968 but call set-up fails.

What is wrong?

AA66..66::

Ensure that the traffic channel frequency (channel number)

is within the range of frequencies supported by the mobile. It is

particularly important to check this if the mobile only supports

part of a frequency band. For example, the 'TETRA 380 MS' chan-

nel plan covers channels 3600 to 3999 (380-390 MHz mobile

transmit, 390-400 MHz mobile receive); a mobile that only cov-

ers 385-390 MHz mobile transmit/395-400 MHz mobile receive

will only cover the channels 3800 to 3999. Ensure that both the

control channel and the traffic channel are within the mobile's

supported frequency range. You may prefer to define a USER

DEFINED channel plan covering only the mobile's supported fre-

quency range so that you can only select channels within the sup-

ported frequency range.

QQ66..77::

Why is the IFR 2968 so particular about the network

parameters?

AA66..77::

The IFR 2968 is not particular at all, however TETRA

mobiles are particular. Until the essential parameters are set up

on the test set (channel plan, offset, control channel, MCC, MNC),

a TETRA mobile will normally ignore the test set completely and

not send any signalling to the test set. Normally a mobile will not

provide any indication to the user that it has found a TETRA base

station signal unless the essential parameters are set correctly.

QQ66..88::

Why can't the IFR 2968 set the network parameters itself

automatically?

AA66..88::

In theory, the 2968 could try all of the parameter values in

turn until the mobile responds. However, with 999 possible coun-

try codes and 9999 possible network codes this is not a practical

proposition. For each of the 10 million combinations, the 2968

would need to wait several seconds to give the mobile time to

find the signal - having found a TETRA signal with the wrong MCC

/ MNC values, the mobile is not going to keep listening to the sig-

nal in case the values change, it will go off and search for signals

with the correct values. If the channel plan (frequency band and

offset) is unknown, this would increase the combinations further,

and if the mobile does not scan the band then all 16000 fre-

quency channels and offsets in the band would have to be tried

each with all 10 million combinations of MCC /MNC.

QQ66..99::

GSM radio test sets don't require the correct network

parameters to be set, why is this necessary for TETRA mobiles on

the IFR 2968?

AA66..99::

A GSM phone attempts to register onto other networks

(roaming) if it doesn't find its home network. Currently TETRA

mobiles do not implement this behaviour, which is known as

'migration' in TETRA rather than 'roaming'. TETRA migration is

defined as a two stage process in which the mobile would identi-

fy itself to the other network as a 'visitor' and would be assigned

a visitor's identity for use on the other network which it could then

use to register and make / receive calls on the visited network. As

part of this process the mobile would provide the identity of its

home network and its own identity.

The IFR 2968 (Phase 3.2 software) implements TETRA migration

so that mobiles which do implement migration can register to the

test set as a visitor and provide the identity of their home network.

TETRA mobiles implementing migration should become available

in the future, since migration has been defined as an optional part

of TIPv4 functionality. However, this does not necessarily mean

that a TETRA mobile supporting migration will attempt to register

to any network - mobiles may be configured with lists of other net-

works with which they are allowed to attempt migration. In any

case, the IFR 2968 still needs to be configured with the correct

channel plan and offset required by the mobile.

All GSM mobiles use SIMs (Subscriber Identity Modules), and it is

common practice to test GSM mobiles using Test SIMs, which

provide the mobile with a test identity (IMSI) of

001/01/0123456789 when the SIM is inserted instead of the nor-

mal network subscription SIM. Currently TETRA mobiles do not

use SIMs and there is no definition for a TETRA Test SIM. The

nearest equivalent that is currently available in TETRA mobiles is

the use of TETRA Test (TT) mode registration, in which the mobile

assumes a home network identity of 001/00001 when TETRA

Test mode is enabled on the mobile.

QQ66..1100::

How do I find out the network parameters for a particu-

lar mobile?

AA66..1100::

There are a number of options which may be appropriate

to the situation:

• Refer to the manufacturer or supplier of the mobile or

the network operator or other body with responsibility

for provision and programming of the mobile.

• Use menu functions or diagnostic menu functions on

the mobile (if available) to display the network parame-

ters.

• Use the mobile's programming tool (if available) to read

the network parameters.

• Check whether the mobile has actually been configured

for a particular network or whether it contains a factory

default configuration.

• If the mobile is known to work with a nearby base sta-

tion, use the 2968 in base station test mode to deter-

mine the essential network parameters, and set up the

2968 in mobile test mode to match the real base sta-

tion. See A6.11 below for details of how to do this.

QQ66..1111::

How do I set up the 2968 to match the network param-

eters of a local TETRA BS?

AA66..1111::

The following method can be used for setting up the

2968 to match the network parameters of a local TETRA base sta-

tion that a TETRA mobile is known to work with, providing that the

base station is reasonably close (e.g. 1-2 km) and you have an

antenna that can receive a clean RF signal at a reasonable level

(typically -75 dBm or higher).

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