A consistent GPS signal is vital to successful Field Tests. Malden’s Time Sync Management techniques minimise the effects of any GPS signal loss by ensuring that DSLA units maintain sufficient time sync accuracy to continue running tests after the GPS signal is lost. Time Sync Management maintains the internal clock to within a few milliseconds of GPS time for up to four hours without a GPS a signal.

This is achieved without the additional bulk and weight of a separate high-stability clock and the additional battery packs to power it.

MultiDSLA can be used to perform two types of Field Test

Field Test is so-called because testing is carried out ‘in the field’. The MultiDSLA system must operate in locations where mobile devices are used: in cars, trains, shopping malls, office buildings and sports arenas. MultiDSLA can be used to perform two types of Field Test:

• Simple Drive Test – A MultiDSLA system is placed in a vehicle. The wireless devices attached to the test system make test calls between each other. An alternative is a Walk Test, in which the test system is wheeled on a trolley in, for example, a sports arena or shopping mall.
• Full Field Test – Wireless devices attached to a MultiDSLA system in a vehicle make test calls with devices attached to a MultiDSLA server at a fixed (office) location. This configuration can also be used for Walk Test.

The Need for Continuous GPS

GPS is used in Field Test applications to add location data and for synchronisation. The use of GPS to provide location data as part of the measurement set is desirable, as it enables testers to map results and to visualise ‘problem’ areas. The Full Field Test configuration also relies on close time synchronisation of the vehicle and server systems to obtain consistent results. Previously this could be achieved only by ensuring continuous GPS availability during testing, as any loss of the GPS signal would jeopardise the integrity of the results.

Short-term GPS signal loss may occur in tunnels or wooded areas, for example, and in indoor locations a GPS signal may not be available at all. Digital Speech Level Analyser (DSLA) firmware now includes Time Sync Management which enables the MultiDSLA test system to operate without GPS for extended periods.

New Features for Field Test

Time Sync Management is just one of a range of new features Malden is adding to MultiDSLA to make it a comprehensive, simple-to-use Field Test solution. Other features include:

• Increased test throughput
• Support for English, German, French, Italian, Dutch and Finnish language material
• The ability to identify the type of radio access network
• Cell ID detection
• Call status monitoring with automatic recovery of dropped calls
• Long call and call access test modes