Influence of the Packet Size on the One-Way Delay on the Down-link in 3G Networks

Abstract—The number of mobile broadband users is increasing.
Furthermore, these users have high expectations into the
capabilities of mobile broadband, comparable to those in fixed
networks. On the other hand, the capacity assignment process
on mobile access links is far from transparent to the user, and its
properties need to be known in order to minimize the impact of
the network on application performance. This paper investigates
the impact of the packet size on the characteristics of the oneway
delay for the down-link in third-generation mobile networks.
For interactive and real-time applications such as VoIP, one-way
delays are of major importance for user perception; however,
they are challenging to measure due to their sensitivity to
clock synchronization. Therefore, the paper applies a robust and
innovative method to assure the quality of these measurements.
We focus on the down-link as this is still the link that carries
the most traffic to the user, and the quality of it will have a
significant impact on all IP-based services.
Results from measurements from several Swedish mobile
operators reveal the possibility to partly control one-way delay
and its variability by choosing appropriate packet sizes. In
particular, packet sizes leading to the use of WCDMA entail
significant but hardly varying one-way delays. On the other hand,
we also show that HDSPA networks can deliver large amounts
of data at rather high speed, but the cost is a huge variability
in the one-way delay.