Laner, Markus; Svoboda, Philipp; Rupp, Markus (Vienna University of Technology, Austria)
Latency in 3G wireless cellular networks is relatively high by design. Hence, optimizing latency will be the key task for improving quality of experience in future mobile networks. This work is a precise dissection of the delay contributions of each element in an operational HSPA cellular network, both in uplink and downlink. The deployed methodology is active probing combined with time-synchronized sensing nodes. The latter enable the tracing of packets on every interfaces along the data-path in a 3G network. Our results show that the major delays are introduced at the user terminal side. Interestingly, each network component shows a higher processing time for data in downlink than in uplink. Further, we assess latency increases carried by the use of legacy network equipment. For reproducibility of the results we provide models for the delay of each HSPA network component. Our findings enable (i) to estimate latencies in existing networks for simulations and network planning and, (ii) to identify reasonable starting points for research on latency reduction in future networks.