(This is part one of a two-part article series on the technical, operational and revenue impacts of deploying Wi-Fi offload to meet mobile data demand.)
Data hungry consumers, powerful mobile devices and rich media applications are creating a data deluge. Some reports estimate mobile data traffic will grow 1,200% by 2017. Mobile operators are successfully managing the data explosion with profitable plans based on use. On the capacity supply side, they are prioritizing spectrum purchases, deploying network efficiency solutions and moving voice traffic to 4G networks. This is easing some of the capacity crunch. But continuing to grow capacity economically presents major challenges, especially considering that revenue will not increase proportionately. With that in mind, how will this growth be funded? Where will the capacity come from? More operators are starting to look to Wi-Fi to help answer these questions.
Micro Networks Powered By Wi-Fi Deliver Major Bandwidth Relief
Micro networks (also known as small cells) provide a cost-effective and flexible solution for operators to move nimbly in addressing surging data traffic. These networks are commonly deployed in indoor locations (e.g. malls, convention centers, subway stations). Compared to traditional cell networks, micro networks can be surgically built to add capacity in specific areas in response to demand. In fact, once an operator has a network in place, it is relatively quick and easy to add capacity with micro networks. It is also usually more efficient and less expensive versus trying to serve indoor demand with outdoor networks.
Micro networks can be made up of Wi-Fi access points, as well as picocells or femtocells that are based on 3G/4G network standards. When picocells and femtocells are based on the same network technology as the macro network they extend, several compelling advantages emerge. This includes built-in device support, integrated security and privacy mechanisms, automatic discovery and smoother handover between networks. However, these networks can be more expensive than Wi-Fi and have usability limitations due to band fragmentation.
Wi-Fi access points have become a popular choice for building micro networks. This is largely due to Wi-Fi bands being uniform around the world and able to support most smartphones and tablets. In contrast, there are around 40 bands globally on which LTE networks will be deployed. Since current mobile devices typically support five to seven bands at most, this severely limits roaming capability for those accessing the network via picocells and femtocells. In the next few years, more devices will support more of these bands, but Wi-Fi remains the more compatible solution today. Lastly, Wi-Fi is poised to offer reduced deployment costs, improved discoverability, security and authentication with the introduction of Next Generation Hotspot (NGH) standards.
Next Generation Hotspots Will Drive Offload Growth
Wi-Fi was originally conceived as a consumer-grade technology. However flexible, configuring the technology to support a carrier grade deployment posed several challenges in the areas of usability and security, ultimately limiting carrier adoption. NGH has been designed to address key challenges related to network discoverability, network authentication and encryption. Key feature of NGH include:
• Network Discoverability: In cellular networks, devices automatically detect available networks to which they can connect without any user intervention. In Wi-Fi, the user traditionally has had to select a network manually whenever they are in a new area. This results in a tedious user experience. The Generic Advertisement Services based on 802.11u in NGH standards will make devices aware of networks in the vicinity and autonomously query which ones can be used based on operator agreements and credentials, thereby eliminating the need for user intervention.
• Network Authentication: In cellular networks, the device or SIM card securely stores user credentials and automatically grants access to valid users . Most of today’s public Wi-Fi networks are either open, which compromises security, or require authentication, which demands user intervention every time a new network is accessed. From a customer experience perspective, it is simply not an option to make customers manually re-authenticate every time they are switched to a different network. The process can be automated for repeat logins, but most of the current solutions for this also introduce security vulnerabilities. NGH standard solves this problem by offering several secure mechanisms for automatic authentication using stored credentials. For devices that have a SIM card, the preferred mechanism is EAP-SIM (Extensible Authentication Protocol) or EAP-AKA. For devices without a SIM card (e.g. tablets without cellular connection or laptops) EAP-TLS or EAP-TTLS are examples of possible options. This mechanism is achieved in hotspot by using Generic Advertisement Services, which communicates network identity and type of security mechanism that the device can leverage
• Encryption: A major area of concern for mobile operators has been ensuring the privacy of communications following initial authentication. Currently, communication on the majority of the public Wi-Fi networks have no or very light encryption. NGH standard solves this problem by using secure WPA2-Entrprise encryption.
The Wi-Fi industry as a whole is proceeding rapidly with standardization, certification and cooperation that are creating a strong foundation for Wi-Fi offload. Wi-Fi Alliance has instituted PasspointTM certification program for validation of NGH capability compliance of Wi-Fi network and device equipment. Wireless Broadband Alliance (WBA) is running an end-to-end Wi-Fi international roaming trial using key elements of Next Generation Hotspot (NGH) such as Passpoint certified equipment supporting 802.11u, 802.1x Wi-Fi networks & EAP authentication methods. The certified devices have just started to hit the market, however it will likely take a couple of years before we see large scale deployments with public networks.
Operators will need every tool at their disposal when it comes to dealing with the projected mobile bandwidth boom. While no one solution can solve all capacity challenges, Wi-Fi offload should be on every operator’s roadmap as a key tool for helping to satisfy unrelenting demand for data on the go.
(In part two of this article series, strategies for off-setting deployment costs and developing new revenue streams will be examined.)
Hillol Roy is a fellow with IBB Consulting and an accomplished wireless industry veteran with over 18 years of wireless business and technology leadership experience. He has guided Wi-Fi business and technology planning for several leading North American cable operators and other Wi-Fi operators.
