Wifi Offload

Cellular traffic offload is emerging as an area of great interest for network providers, as they are struggling to keep up with the exponential growth in mobile data traffic which may eventually choke up cellular network capacity. HSC recognized this trend early on and has developed expertise and solutions in various technologies and implementations which allow the cellular networks to offload data. Some of these are:

  • 3GPP interworking with non-3GPP access networks over S2a, S2b and S2c interfaces
  • Implementing 802.11u / Hotspot 2.0 based interworking support
  • ANDSF communication with UE, over S14 interface, using OAM-DM protocol for discovery and policing (ISMP, ISRP)
  • Seamless WiFi handover/handoff /offload and IP Flow Mobility (IFOM)
  • Firm understanding of WLAN specifications along with amendments like 802.11u, r, k etc.
  • Comprehensive knowledge of the glue logic between cellular core network and WLAN; such as TWAG/ePDG and respective protocols like GTP/GTPv2/PMIP etc.
  • In-depth understanding of and extensive experience with IP protocols like IPv4/IPv6, IPSec, IP based QoS (DiffServ), IPv6 migration, DSMIPv6, flow based classification etc.

HSC has also created an end-to-end IFOM testing facility using FOSS such as OpenWrt, HostApd, Wpa supplicant, FreeRadius, libdmclient, and more. We deeply understand their internals, installation and configuration.

The Case For Wireless Data Offload And Techniques

The advent of smart devices and applications (video streaming in particular) has ignited a surge of users needing to gather more and more data - resulting in a tsunami of data traffic. This is causing network operators to start looking for alternative techniques to save cellular access networks from this surge of data traffic, and to further improve the user experience in such a heavily-loaded access network. Limiting data plans will only prove detrimental for operators as this would trigger an exodus of its subscribers to the competition. So what is the alternative?

With analysts’ claims that half of the mobile data traffic will be offloaded in future, there is a tremendous business opportunity for equipment manufacturers and software vendors to come up with innovative solutions.

HSC has been tracking the work being done by 3GPP, along with IEEE, to tackle this challenge. With this joint effort, the following new techniques have surfaced and are being evaluated for their use in increasing network capacity:

  • WiFi Handover / IFOM
  • LIPA
  • SIPTO

Because of its omnipresence in today’s connected world and supported functionality in most mobile devices, WiFi offload, also known as wireless handover (or wireless handoff), is the most sought-after of these techniques. Its support of RSNA/802.11X based enhanced security and its unlicensed spectrum only add to the popularity of WiFi offload. Enhancing network capacity by utilizing WLAN as an additional RAN to their cellular core network is quickly becoming the obvious choice for network operators looking to boost performance.

LIPA and SIPTO are other standardized techniques for traffic offloading which require minimal changes in UE signalling, but these require deployment of H(e)NBs and L-GW(s) components. This is not the case with WiFi handoff.

The solution to WiFi offload is not straightforward. Any new technology requires the introduction of new network components, new functionality and integration with existing systems for a seamless experience. WiFi offload brings with it a new set of challenges such as how to automatically and seamlessly connect WiFi and cellular domains, how to integrate a WiFi network with operator’s policy and charging systems, and so on. HSC has been working with its customers on these and several other challenges.

(Looking for something different? Head over to our radio and wireless engineering page for more information on our technical skill areas and the industries we work with.)

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