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The growing synergy between Small Cells and Wi-Fi


Post Small Cells World Summit whitepaper

Post Small Cells World Summit whitepaper

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  • 1. The growing synergy between Small Cells and Wi-Fi Is a wireless data tsunami really about to hit the industry? There are surprisingly divergent views across the industry about an impending dramatic increase in mobile data traffic demand – the so-called data tsunami – and whether mobile network operators are fully prepared to meet it. Many conference presenters refer to the Cisco VNI forecast1 , which have proved remarkably accurate to date. Although recently revised downwards, this still projects a 13-fold global growth between 2012 and 2017. Dense urban areas can expect an even stronger increase. Today’s traffic levels are already substantial. Actix, who provide performance management systems for many operators worldwide, identify that a single square kilometre in a mature 3G urban network handles on average more than 50,000 unique subscribers generating 300 GBytes of data per day2 . That results through more than 800,000 3G data connections, and 45,000 3G and 2G voice calls. Virgin Media, who installed free public Wi-Fi throughout the London Underground, report over 1 million Wi-Fi sessions per day3 and average throughput of 18Mbps. Factors affecting mobile data traffic growth include the pace of LTE take-up, the maturity of 3.5G DC-HSPA+ deployments and significant use of Wi-Fi. The health of regional economies, appetite for new technology, cost of spectrum, ARPU and competitive environment all add further variability. Verizon CEO Lowell McAdam reported4 that about 50% of mobile data on their network is now video and is expected to reach 66% by 2017. The impact of this growth affects network operators differently. Speaking at April’s TNMO conference, Telecom Austria was at pains to point out that they saw traffic increasing linearly rather than exponentially on their network, and felt this was entirely manageable. In Asia, we have seen dramatic peak traffic levels from early adopters of LTE, especially in Korea and Japan. Gordon Mansfield, AVP at AT&T leading their LTE and Small Cell initiatives pointed to a huge step change in traffic demand after launching LTE, partly due to their being many devices already in place able to use it. He believes that European operators may be surprised at how quickly traffic increases once LTE develops.
  • 2. Mobile Operators don’t see the whole picture But perhaps mobile operators aren’t seeing the whole picture about data traffic that their customers consume. Before smartphones, all transmissions to and from mobile phones were sent via the mobile network – almost entirely voice and SMS text. Today, the majority of data traffic bypasses the mobile operator, using private and public Wi-Fi or being side-loaded directly from a computer. One way to capture a better picture of this is from aggregate statistics of traffic optimization apps, running on many smartphones. A study from Mobidia5 indicates that at least 50% of wireless data makes its way to/from smartphones via Wi-Fi, and less than 50% via the cellular networks, with only around 2% travelling over Service Provider Wi-Fi. This excludes any side- loaded data delivered by wired connection from iTunes or similar. With the advent of HotSpot 2.0 and seamless roaming using cellular SIM cards, it seems likely that SP Wi-Fi use will quickly grow and further augment cellular data. A missed opportunity? The rapid growth of Wi-Fi is partly a consumer–led response for convenient wireless connectivity in the home and office that wasn’t fully satisfied by the mobile network industry. The requirement of low price point, short range and private secure access didn’t match the characteristics of wide area public service cellular networks. The mobile industry did not adopt femtocells as rapidly as expected, leaving the market open for hotels, pubs and cafés to install their own Wi-Fi. In our connected world today, consumers actively seek out accommodation and venues with good (and often free) Wi-Fi service6 . In response, the tourist industry seeks to satisfy that need. For example, Tourism Australia is encouraging hoteliers to offer free Wi-Fi throughout the country7 . Instead, we saw mobile operators derive short term commercial advantage in promoting the use of Wi-Fi to offload traffic from their networks. It seemed they didn’t care what their users did - just so long as they did it somewhere else. Offloaded traffic was unmanaged, and operators didn’t have sight of what their users were really doing. From 2009, operators such as Sprint actively mandated8 that all smartphones sold for use on their networks were Wi-Fi capable, helping to relieve pressure on the network. The trend continues to grow, with operators such as KDDI Japan now offloading 50% of its wireless traffic to its 220,000 public hotspots, AT&T Wireless doubling the number of public Wi-Fi hotspot sessions in the last year to over 2.7 Billion connections, and even developing countries beginning extensive public access Wi-Fi investment throughout Africa and South-East Asia9 .
  • 3. Working towards a closer synergy between cellular and Wi-Fi Commercial partnerships between cellular operators and Wi-Fi aggregators have evolved, allowing cellular customers to use their mobile accounts to access Wi-Fi. The customer experience has varied tremendously from its early stage where multiple login screens, security concerns and high one-off connection charges discouraged casual take-up. Wi-Fi aggregators offer connection managers and Apps to simplify the experience, but these are usually locked to individual resellers. More recently, we’ve seen carriers building out their own Wi-Fi networks, offering free or low cost access to both their own and competitors customers. Examples including AT&T acquiring Wayport in 200810 , Telefonica O2 deploying Wi-Fi in London for the 2012 Olympics, Virgin Media installing Wi-Fi throughout the London Underground and China Mobile now exceeding 4 million public access Wi-Fi hotspots nationwide. Aggregate Wi-Fi networks continue to expand, with FON now reaching 7 million access points throughout more than 100 countries11 . LTE and Wi-Fi is also a popular combination. In South Korea, both SK Telecom and KT have installed more than 10,000 LTE/Wi-Fi capable small cells each. The next stage involves much closer interworking between Wi-Fi and Cellular worlds. This is particularly true for public access Wi-Fi which is becoming seen as “just another radio access technology” to be used alongside 3G and LTE. Combining cellular and Wi-Fi into the same service Increasing levels of integration between the cellular and Wi-Fi networks have evolved over time12 . There are four stages of technical integration:  Independent access to Wi-Fi, primarily for data offload  SIM authentication using HotSpot 2.0, simplifying and automating access to a cellular network’s own and partner Wi-Fi access points  Sharing a common core, billing and control network, allowing the same services and support to be used for Wi-Fi and cellular traffic  Intelligent traffic steering to determine which users and traffic types are redirected to use Wi-Fi Today, most cellular and Wi-Fi networks remain as parallel architectures requiring devices to cope with separate IP addresses, authentication methods and traffic routing. While some of the complexity is hidden from the end user by using a mobile App, there remain some practical issues that have limited adoption. Physical small cell products are now available which integrate these different technologies. Many operators are mandating this in their procurement specifications and most small cell vendors specifically offer this option.
  • 4. Examples include, but are not limited to, Ubiquisys13 , ip.access14 , Nokia- Siemens15 , Cisco16 , Contela17 and Qucell18 . HotSpot 2.0 greatly simplifies the users interaction required to select and connect through compatible access points and networks. Gone is the difficult choice from a dubious list of potential networks and login portal pages. Once adopted, this should simplify and speed up the selection and access to public Wi-Fi. A further step uses solutions that retain the same IP address and routing through the core network during handover to and from Wi-Fi. Seamless access to secure Wi-Fi service will allow Service Provider Wi-Fi usage to grow quickly. Initiatives by the WBA (Wireless Broadband Alliance) integrate the back-office element of the operation, interworking with and building on the existing roaming procedures and settlement processes used by hundreds of cellular operators worldwide. It is important to recognize that Wi-Fi quality can be affected by many aspects outside the network operator’s control, so requires active monitoring of quality of service and the ability to revert back to licenced spectrum where and when required. End-to-end solutions capable of traffic steering are maturing from vendors including Nokia-Siemens’ Smart Wi-Fi19 (which uses Ruckus Wireless access points), Cisco’s Adaptive Intelligent Routing20 and Ericsson’s Carrier Wi-Fi21 (incorporating the recently acquired BelAir product set). Using public Wi-Fi to acquire future small cell sites One commercial driver for cellular operators to deploy Wi-Fi hotspots themselves is the potential for a “lamp-grab” as operators install public Wi-Fi service, then claim site ownership, retaining the option to upgrade specific sites to 3G and/or LTE in the future when traffic demand justifies it. Lamp- posts or light-poles typify the popular outdoor street locations which already have power and common ownership. We have also seen the mentality of cellular operators towards public access Wi-Fi develop and mature. Many are specifying that future cellular small cells include Wi-Fi capability, integrated to allow seamless handover without re- authentication. Wi-Fi is being viewed as just another radio access technology, widely available on smartphones and free from spectrum fees. Monitoring the QoS received by end users will be important though, so that traffic can revert back to licensed spectrum where performance is unsatisfactory. All traffic can then be routed via the same core network, delivering uniform services (e.g. parental control, spam filtering, policy management, location services etc.) and allowing the same treatment to be applied regardless of access technology. Where will the capacity be installed? A recent survey of mobile network operators confirmed aggressive plans for substantial capacity upgrades. The majority forecast capacity increases of 20x
  • 5. or more by 2017, with 24% indicating they have plans for 50x in that timeframe22 . Overall, the peak and growing traffic demand is for indoor use, which can be more difficult to serve efficiently from an outdoor mobile network. We often sit when making greatest use of our data devices, whether at home, in the office, taking public transport or at a restaurant, bar, café, stadium etc. The availability of new spectrum from the digital dividend at 700-850MHz will help in-building penetration, but not necessarily add that much network capacity. The highest traffic peaks are in the urban downtown/central business districts. In some cases, repeaters had been installed to improve in-building coverage. Verizon reported23 cases where these have started to affect users in the street outside, choking off capacity from those who might expect better performance. Several Asian operators have also publicly undertaken substantial upgrade programs, such as SK Telecom replacing many repeaters24 with small cells that add further capacity, improving both indoor and outdoor network performance. Network Sharing The mobile industry has seen much consolidation in recent years, some more visible than others. Site sharing and RAN sharing are much more common, reducing duplication in both the number of cellsites and the equipment itself. There is a lack of clarity across the industry about whether small cell networks should be included in these RAN sharing arrangements. Some see small cells as a major differentiator while others are worried about potential high costs. There are also practical limits as to how much functionality, capacity and different radio technologies can be squeezed into a form factor suitable for unobtrusive mounting in public spaces. It’s quite possible that indoor (residential/enterprise) small cells may be treated differently for network sharing than public access metrocells and picocells. The former are much more closely tied to individual customers, linking both their own revenue stream and targeted customer satisfaction. The latter are part of a wider network capability that is shared across the entire user base and typically have higher costs per site. Wi-Fi doesn’t have quite the same constraints, with multiple SSIDs and roaming agreements allowing the same hotspot to provide service to subscribers of multiple networks. Performance can be limited more by unknown and transitory issues, such as the temporary use of Mi-Fi, potential interference from excessive deployment of access points in close proximity and other factors. Maximum spectral efficiency is improved when radio access points are co- ordinated, operating in licensed spectrum and fully optimized. New LTE-
  • 6. Advanced techniques such as CoMP (Co-ordinated Multi-Path) promise extremely high throughput for both uplink and downlink, but require very precise phase time-synchronisation to achieve it. It seems likely these will be used only in extreme cases, found in a few highly populated open spaces such as town squares or sports stadiums. The maturity of Service Provider Wi-Fi solutions is now generally accepted by the cellular industry, which views it as another highly effective radio access technology to be integrated into their offering. Technically advanced features have become equally applicable for both Wi-Fi and cellular small cells, such as beam forming, self-organization and automatic frequency selection. Strong evidence of Wi-Fi network maturity was proven by the outstanding Wi-Fi network performance at this year’s Mobile World Congress, which in some locations was better than cellular service, coping well with heavy demand even in the press room area. The opportunity for services rather than just a dumb pipe The combination of cellular and Wi-Fi opens up the possibility for a range of services to consumers and other businesses. Aggregated, anonymous information can be of great value to those managing large facilities or city centre areas. For example, being able to track how many and how quickly passengers are passing through check-in allows the Copenhagen airport operations team to predict where and when staff need to be deployed25 . In retail malls or large stores, tracing the patterns of footfall enable improved store design. The use of small cells, both Wi-Fi and cellular, allow better resolution of location data, especially indoors where GPS may not be available. We are familiar with so-called Free Wi-Fi zones, effectively sponsored by the site owner, such as a café or hotel. Telefonica O2 have installed free Wi-Fi in many retail partner stores26 , presenting a venue specific welcome page the first time a web browser is used with relevant content for visitors. A similar service can also be provided using small cells to permit free access to cellular data (i.e. not counting towards the monthly data allowance) within certain areas. Vodafone Greece has pioneered a free 3G zone service in up to 200 locations, sending a text message to users to notify them when they will benefit from the service27 . Individual users may choose to opt in to a variety of helpful location based applications. Examples include tourist guides which walk you around a city or museum, identify nearby facilities or log your sporting activity. Access to Wi-Fi hotspots improves the resolution of geo-location data and also ensures better connections. More intelligence is being moved to the edge of the network, with application servers being integrated into small cells themselves. The quickest benefit of this approach is from data caching, relieving peak capacity demand on the
  • 7. backhaul and reducing latency when accessing common content. Ubiquisys SmartCell and Altobridge DatE have both implemented solutions into small cells that offer compelling business cases. An alternative is to run applications on a local small cell controller. For example, Spidercloud’s Services Node28 allows authorised enterprise users to connect directly and securely to their office IT systems, whether using 3G or Wi-Fi. Nokia-Siemens’ Liquid Applications concept allows application processing and data caching within their Flexi-Zone controller in conjunction with Radio Applications Cloud Servers29 . As the Wi-Fi and cellular industry develop common solutions, we can expect to see greater synergy in the services and features offered, making best use of both technologies. 1 Cisco Virtual Network Index 2 Actix Press Release, May 2013 3 Virgin Media Press Release, January 2013 4 Verizon CEO reported at National Association of Broadcasters, April 2013 5 Understanding the Role of Managed Public Wi-Fi, Mobidia, February 2013 6 BBC report highlighting the value of internet access when travelling 7 BBC report interviewing head of Tourism Australia 8 In 2009, Sprint mandated that all smartphones were Wi-Fi capable: 9 China Mobile leading the way as emerging market operators embrace Wi-Fi, Matt Ablott, Mobile World Live, March 2013 10 ATT Press Release, November 2008 11 Deutsche Telekom press release on joining FON partnership, March 2013 12 Emerging innovations in Carrier Wi-Fi, Alepo, September 2012 13 Ubiquisys Product Portfolio 14 ip.access demonstrate LTE to Wi-Fi seamless handover, February 2013 15 Nokia-Siemens Networks Smart Wi-Fi and Small Cell Interview, ThinkSmallCell, May 2013 16 Cisco Small Cell Solutions 17 Contela small cell product brochure 18 Qucell Press release, Small Cells Americas, Dec 2012 19 Nokia-Siemens Smart Wi-Fi solution 20 Cisco Adaptive Intelligent Routing solution 21 Ericsson Carrier Wi-Fi solution 22 Managing the new mobile data network, Rethink Research, June 2012 23 Scott Semone, Verizon RF Maintenance and Engineering Group, April 2013 24 Small Cells – What’s the big idea including SK Telecom case study, 2012 25 Smarter Air Travel case study video, Copenhagen Airport 26 Cisco help O2 monetize public Wi-Fi 27 Vodafone sets Small Cells Free in Greece, Heavy Reading 28 Spidercloud E-RAN solution 29 Nokia-Siemens Press Release, SK Telecom collaborate on Liquid Applications