Mobility Testing Concept and Instruction of organizing Mobility Testing process

1. Mobility Testing Overview and
Instructions
Author: Alexandra Titova
Version: 1.1
Date: 2013-08-23

2. Table of Content
• Mobility testing concept
• Handover
• Examples of Handovers in UTRAN
• Preparation: mobility Test Plan
• Preparation: drive routes
• Preparation: organizing the trip
• Preparation: equipment
• Preparation: tasks
• During mobility test
• After the mobility test
• Common recommendations
• Common problems and risks

3. Mobility testing concept
Mobility Testing is a test performed in real cellular networks.
It can identify problems such as:
• Voice Call efficiency/statistics: dropped/failed/missed/blocked/hangs calls
• UE operability in different types of cell-reselections/handovers
• Data Performance: uploading/downloading data in movement/during handovers
• UE Performance Testing in different network conditions
• Handling GPS location co-ordinates, Location Based Services (like maps)
• UE processing in Roaming and Time Zone Transition
A Mobility Test during the day shows the actual condition of the network - especially in relation
to loading aspect of it. Moreover, the mobility test conducted at night allows you to make, for
example, tests on transmitters without affecting most users.

4. HandoverOne of the main concept in Mobility Testing is a Handover. Handover refers to a process of
transferring of an UE from its current cell (called source) to a new cell (called target).
There are two types of handover – intra-cell and inter-cell. When a source and the target are the same
cell and only the used channel is changed during the handover it is called intra-cell handover. The
handover when the source and the target cells are different is called inter-cell.
Unsuccessful handover is often the cause of dropped calls/data
transfer or even loose network signal. Successful handovers
depends on different conditions and criteria of successful run
is specified in particular test procedure.
Example of a handover
Inter-cell, inter BSC handover in GERAN: The subscriber moves from source
Cell to a target one, which is served by another BSC. In this case
the handover process is carried out by the MSC, but, the decision
to make the handover is still done by the first BSC. The connection
with the first BSC is released when the connection with the new
BSC (and BTS) is set up successfully.

5. Examples of Handovers in UTRAN
A UE should be tested in different network
changing conditions, for example:
• Location area update
• Routing area update
Different type of handovers are also
specified and should be checked
accordingly.

6. Preparation: mobility Test Plan
• A Mobility Testing plan should be ready before starting test activity.
It should contain test schedule, resource plan, environmental needs
and every cycle mobility testing coverage
• Mobility Test Plan can be a part of Generic Test Part or a separate
Plan
Preparation Plan in general:
• Learn Mobility Test Plan
• Prepare drive routes
• Organize the trip
• Prepare all the required equipment
• Do testing according to a task
• Collect and analyze the results
Let’s look through these actions in details.

7. Preparation: drive routes
• Drive routes should be available for every Mobile Network Operator which are planned for
testing. Routes conditions should correspond to the test purposes and should have required
tested conditions mentioned in test cases (examples of network states/conditions which
might be required: inter-RAT*, LAU*, RAU*, RNC* changing, etc.)
• There are various sources of testing routes: it can be provided by a Field Trial Qualified
(FTQ) Operators in GCF, disclosed by Operator under NDA or obtained from open sources
or created based on Mobility Testing experience in some region.
• Routes preparation is separate task which is handled during FT preparation period
• Some applications allows the image to be loaded as
the software background (geo-referencing, e.g. G-MoN,
GPSed, Netmonitor on Android). This makes it much easier
to direct routes to be followed.
RAT* - Radio Access Technology
LAU* – Location Area Update
RAU* – Routing Area Update
RNC* – Radio Network Controller

8. Preparation: organizing the trip
• Test Project Manager and Technical Expert shall provide detailed work
instructions and test plan. There are some general recommendation which
should be followed. Let’s list them.
• Mobility cycles should be planned in advance and have definite timetable.
• Recommendation: plan 80% time of the day for driving and 20% for analysing
results, raising issues and providing reports.
• Plan some extra time for checking the routes, or some unexpected lack of
required conditions. Route investigation time depends on the scope of testing
and it’s decided in every particular case. For example 1 man/day should be spent
to explore the correct route for 1 Network Operator in new place or where routes
are obsolete.
• To minimize expenses and save time it’s recommended to have a contract
with taxi/car rent agency. Procedure of renting a taxi/car should be
predefined. Test engineer should follow this procedure. Use security and
trust companies to get cars from. Save all cheques and supporting
documents. It’s recommended to check if taxi company have insurance for
passengers.

9. Preparation: equipment
• Make a check list of equipment you will require during mobility
testing, for example:
Check in advance
• Prepare a reference UE. It’s a reliable device confirmed by customer for using it in comparing behavior and
draw in questionable situations
• Data cables for all devices
• SIM cards
• Test phone numbers or another supporting devices for making test calls or messaging
• Note: special services can be used instead, e.g. test call center, NowSMS, Mail bomber. Usually special
numbers can be provided by operator for test purposes.
• Laptop with installed tools for capturing SW traces and logs, cellular network monitor
• Satellite navigation tool which is capable to mark places where the network event or error occurred
Check on the eve
• UE (User Equipment – device under test). Check the correct SW is installed before start
• SIM cards plan charges and conditions should be under control
• Car power adapters and inverters to 220V to power test equipment in car
• Before you start, check all connections functioning. Mainly,
make sure that all equipment is properly energized

10. Preparation: tasks
• Learn planned test cases. It’s recommended to have a
copy of test cases on your laptop during testing session
or a printed version.
• Plan the optimal execution sequence and route
• Make sure the planned route corresponds to planned test
purposes: contains required network conditions. It can
happen that some expected conditions will not be
covered on the route
• Required UE settings and services setup instructions
should be available in field. Usually the required settings
are specified in AnexBs FTQ documentation or Network
operator specifications and collected in the Country
specific FT guideline.

11. During mobility test
• Use logging tools if available to collect logs during the
testing both on test and reference UE
• Pay attention to reference UE behavior when unexpected issue appears on test UE
• If an issue is observed it’s recommended to do the
following:
• Record a short issue description, steps to reproduce and fail rate of the issue
• Collect all relevant logs to a separate folder
• A location where the issue was found should be marked (GPS coordinates or a point on the map)
• Describe the behavior of the reference phone at the same time when issue has been found
• Specify preconditions: phone settings (e.g. Preferred Network, phone state, Connection state, etc.)
and network conditions (e.g. 3G area or RAU, weather condition, driving speed, tunnel, etc.)
• Make screenshots if possible
• Repair the UE after an issue occurs, start logging again (if applicable) and continue testing. Issue
reporting should be done after the driving is complete.
• Don’t forget about security. Keep any equipment safe, be
attentive and careful.

12. After the mobility test
• Report all found errors to Error Management
tool. Follow error reporting instructions
• Collect logs from mobility tests. Usually logs for
both passed and failed cases are being collected
• Plan the next working day, e.g. arrange the taxi
for driving if required
• Prepare daily/status report if required

13. Common recommendations
• Country specific FT guidelines recommended to be used and updated with
actual information It usually contains operator drive routes, services
configuration, SIM cards configuration, etc.
• All the logs should be collected and sorted by dates/devices.
• Have a supporting letter, preferable on the language of the country your are
working, in case of police officer ask. Be ready to answer question about
actions you are doing . Letters shall be prepared together with HR and
signed off by HR
• Keep cheques and any documents from taxi, payment for equipment and
payment for the SIM cards balance
• Keep all the contacts you may need during the work: taxi agency, manager’s
mobile, emergency call number
• Pay much attention on safety and security of the trip/taxi/equipment
• In case if it’s a test engineer’s first trip it’s recommended to do preliminary
non-mobility test cases to get familiar with the device features and settings.
It would be nice to have a Test mobility drive on a known route or with a
qualified Test Expert

14. Common problems and risks
• Car can be late: call to the taxi driver or agency to make sure everything is
ok
• Car can not come: notify your Project Manager or Test Expert, plan another
(e.g. non-mobility) task activities for this day
• Police or other authority asks about your activities during the drive test: it is
recommended to prepare verbal explanation in advance with your manager
and if required provide the supporting letter to authority, don’t worry
• Environment lost/stolen: let your manager know about the incident.
He/she will help to solve the problem. It might be required ask locals for
help (taxi driver or hotel receptionist) to write a statement to the police
• Rush hours: try to plan your trips according to rush hours usually happens
• Have the emergency call numbers (police, ambulance, insurance, Project
Manager) always at your hand
• Watch the video to see the example of drive testing and one possible situation which can happen
during Mobility Testing.
It’s available on http://globalcertificationforum.org Or login and click “official documents” and then “Industry Technical Documents” ->GSMA documents -> Field Trial Day (video).