Network-Wide Measurement of GPRS Bandwidth and Latency

Abstract

Complementing a recently collected large data set on the TCP connection termination latency in GPRS networks we analyze server-side log data generated in a large scale automatic toll system to observe the network bandwidth. After a recent architectural change the on-board units (OBUs) record GPS tracks and transmit track data to the central system for processing rather than transmitting the toll data after local processing. The bandwidth in upload direction is estimated from the server-side log entries and corrected for the network latency. The data collected allows comparing the performance of seven types of OBUs in three GPRS networks over time.

While the three networks differ in the average bandwidth offered, the biggest performance impact is the OBU type where modems with the same specification yield different upload rates. In addition we update the GPRS network latency data by fitting two statistical distributions, improving markedly on the prior results.