Hi,
with short calls you make QoS measurements, better picture regarding call drops etc., let’s say you make 200 short calls for a cell or cells in the specific area, 2 drops it means 1% of call drop.
Long calls is suitable for handover success rate measurement etc., let’s say with just one call in good network you can measure all streets of the city and you’ll have a better picture regarding handovers, how many are failed or succeeded.
Best Regards,
Rex