On the performance of TETRA short data service-transport layer

This paper presents the results of an extensive measurement survey on the performance of Short Data Service Transport Layer (SDS-TL) of Terrestrial Trunked Radio (TETRA) cellular networks. We developed a novel software measurement platform that runs over the TETRA Peripheral Equipment Interface (PEI), generates SDS-TL traffic, performs measurements, and presents statistics of QoS metrics. The measurement platform was utilized in two measurement campaigns: in the first one, two terminals were co-located in the same TETRA cell, and in the second campaign the terminals were positioned in different cells. Measurements were taken for SDS-TL sizes varying from 10 to 190 bytes (excluding the TL header) with an increment of 5 bytes. For each SDS-TL size, 1,500 messages were exchanged through the measurement platform between the TETRA mobile terminals. We repeated all measurements for three intertransmission intervals, namely 2, 1.5, and 1 s, corresponding to measurement durations-for each set of 1,500 SDS-TL- of approximate to 3,000, 2,250 and 1,500 s, respectively. Hence, 166,500 SDS-TL messages were exchanged between two terminals for each measurement campaign. Results obtained include the end-to-end transmission delay (mean and standard deviation) and the percentage of lost SDS-TL versus the message size for the three intertransmission intervals. The effects of inadequate radio capacity as well as gaps in the radiocoverage can be easily identified through the measurement platform, and we analyze such representative cases.