Latency in Broad-Band Mobile Networks

Whilst currently available speeds on Mobile 3G Networks are comparable with many fixed broadband carriers, RTT is still away from the values achieved in fixed NWs. There is still significant room for improvement of latency in 3 G NWs to provide the best quality of experience for broadband services, therefore, latency is a key parameter that should be taken into account in future 3G NW configurations. The goal of this paper is to demonstrate the high impact latency has on current Mobile NWs and also to present ways that should be followed to reduce RTT, based on real NW measurements. In realizing this challenge, the current state of HSPA NWs in terms of latency have been analyzed, the sensitivity to latency of that traffic carried by the 3G NW quantified and measuring the proportional contribution of RTT from all the elements of the NW. Initial analysis shows that the UTRAN is, currently, the predominant factor in E2E latency for 3G NWs and therefore this study focuses more on this aspect. The next step has been to study the reduction of latency on 3G real NWs by means of current technology optimization(s) and planned technology deployment. Finally, it was investigated how QoS differentiation can be optimised for sustaining RTT over a potentially congested NW in several of its interfaces and/or nodes.