Wireless Carriers to MSOs: Can We Borrow your WiFi for Backhaul?

The cable industry's involvement in the cellular backhaul sector is a story of strange bedfellows: Many of the companies to which cable is lending a hand (and a good deal of fiber) at least in part are owned by telephone companies.That awkwardness is being thrust aside because of the mutual benefits of helping each other. The first phase involves little more than raw bandwidth. The cellular carriers pay the cable operators for fiber and microwave connectivity that helps internetwork the growing menagerie of cell sites and to bring the data back toward the core of the carriers' network. That business is established and growing.Like a couple that has been casually dating for a while, the two are looking to take the relationship to another level. This will happen during the next year or so. The key is the wireless carriers' desire to offload as much traffic as they can from expensive licensed to much cheaper unlicensed spectrum used by the WiFi sector. Cable operators can be a great enabler of this constructive siphoning of data.It is a tricky transition, but one that MSO staffs can make, said Purva Rajkotia, the director of product management for Qualcomm. "Cable's NOCs are really good, and they have experience dealing with customers, though I am not sure how much experience they have dealing with wireless customers," he said. "I don’t think the WiFi industry is something operators can't learn. [The inexperience] is something they could easily overcome."Cellular's use of cable WiFi infrastructure to backhaul signals is a serendipitous confluence of three discrete developments that are occurring roughly in sync. The first is the emergence of small cells, which constitute a new layer between the rapidly multiplying smartphones and tablets and the macrocells which, until recently, carried the entire load. The second trend is the cable industry's rapidly growing WiFi business, which, of course, has led it to create a bigger and more sophisticated infrastructure. Finally, a more cellular-like approach to roaming between WiFi access points called Hotspot 2.0 - which is certified under a WiFi Alliance program called Passpoint - is providing the basic tools that will enable the WiFi and cellular worlds to work together seamlessly.Currently, cellular signals from a smartphone or a tablet are transmitted to a macrocell tower and from there dispatched to the wireless packet core (WPC), which, as the name suggests, is the interior of the carrier's network. Cable operators' role can be to take control of this traffic from the moment a text is sent or a voice session established and deliver it to the WPC. This will spare the carriers' use of cellular spectrum.For one thing, mobile devices are ready. For the past couple of years, devices have built with both cellular and WiFi functionality, said Jay Fausch, the director of cable MSO marketing for Alcatel Lucent. He said the same authentication protocol that to this point has allowed transmission of the traffic upstream over the cellular spectrum can do double duty and authorize transmission on cable operators' WiFi network.Thus, the data can be ticketed for the upstream trip on either network. Precisely how this is done - whether a particular packet should be sent via cellular or WiFi - can be controlled via a 3rd Generation Partnership Project (3GPP) protocol called the Access Network Discovery and Selection Function (ANDSF), which can be downloaded to users' devices. ANDSF provides operators with the ability to set rules for conditions under which one path or another is used. Older phones that don't have WiFi functionality built in can participate as well: Uploads from these devices can be managed via software in a home gateway, said Naveen Chhangani, the worldwide director of product marketing/management for NETGEAR.The rules governing use of the networks can be done in real time, so the switchover from cellular to WiFi or vice versa can be responsive to spikes in traffic on either network. Other factors - the value of the data, the time of day and myriad others - can be reflected in the policies. "The power of ANDSF is that if operator or subscriber wishes to change policy, that [new policy] can be pushed out." Fausch said.What remains to be worked out is not only the technical aspects but the business model for such a relationship. "The key to success here is to have seamless mobility going between the licensed and unlicensed spectrum," said Lisa Garza, the senior manager of marketing for Cisco's Service Provider Mobility Business. "That is the critical component. If it is not part of equation, it will not work. It has to have the same underlying architecture."What is starting now as a way to supplement cellular spectrum may have the longer term impact of shifting the focus more fully to WiFi. Rajkotia points to Republic Wireless, a small wireless company headquartered in Raleigh, NC, that is offering unlimited data, voice and text services for rates as low as $19 per month. It is doing this by using cellular and WiFi in equal measure. This goes beyond backhaul to show the potential of the marriage between the two types of networking.The bottom line is that the need is driving the cellular industry into the hands of cable operators, potentially to the advantage of both. "I think this is very, very promising," said Chhangani.Carl Weinschenk is the Senior Editor of Broadband Technology Report. Contact him at [email protected].