Reference:
[1]
Mobile Data Offload for 3G Networks
[2]
Mobile Data Offloading through Opportunistic Communications and Social
Participation
[3]
Femtocell Networks: A Survey
There
are two types of existing solutions to alleviate the traffic load on cellular
networks: offloading to femtocells and WiFi networks.
1. Femtocell
for Indoor Environments
Originally,
the femtocell technology (i.e., access point base stations) was proposed to
offer better indoor voice and data services of cellular networks. Femtocells
work on the same licensed spectrum as the macrocells of cellular networks and
thus do not require special hardware support on mobile phones. But customers may
need to install short range base stations in residential or small-business
environment, for which they will provide Internet connections. Due to their
small cell size, femtocells can lower transmission power and achieve higher
signal-to-interference-plus-noise ratio (SINR), thus reducing the energy
consumption of mobile phones. Cellular operators can reduce the traffic on their
core networks when indoor users switch from macrocells to femtocells. A
literature review about the technical details and challenges of femtocells can
be found in Chandrasekhar et al.[3]
2.Cellular
Traffic Offloading to WiFi Networks
Compared to
femtocells, WiFi networks work on the unlicensed frequency bands and thus cause
no interference with 3G cellular networks. As a result, cellular network
operators, including AT&T, T-Mobile, Vodafone, and Orange, have deployed or
acquired WiFi networks worldwide [1]. Meanwhile, there are already several
offloading solutions and applications proposed from the industry. For instance,
the Line2 iPhone application (available at http://www.line2.com) clones the phone’s own software
and can initiate voice calls over WiFi networks. iPassConnect enables end users
to switch between 3G cellular and WiFi connections smoothly, and provides them a
one-touch login for more than 100,000 hotspots operated by 100t providers.
Recently, Balasubramanian et al. have proposed a scheme called Wiffler to
augment mobile 3G networks using WiFi for delay-tolerant
applications.
Offloading
cellular traffic to femtocells and WiFi networks is limited by their network
deployment and relies on the availability of Internet access. Instead, we
offload mobile data traffic through opportunistic communications for information
dissemination, in metropolitan areas.
Cellular Traffic Offloading,布布扣,bubuko.com