|Topic:||VoIP, the WiMAX killer app?|
|Title:||President and CEO|
Mike Pratt is the President and CEO of Aperto Networks, a developer of advanced WiMAX base stations and subscriber units. Mr Pratt, a telecommunications executive with over 20 years of general management, engineering, marketing and manufacturing experience, was until recently the President of ADC’s Active Infrastructure business unit. Prior to this, he served as Executive Vice President, Worldwide Access/Broadband Systems at Marconi, and has held executive and managerial positions at RELTEC, DSC and Bell Labs. Mr Pratt holds a Master’s of Engineering in Mechanical Engineering from Carnegie Mellon University, and a Bachelor’s of Engineering in Mechanical Engineering from the University of Nebraska.
Worldwide Interoperability for Microwave Access, WiMAX, is a new, heavy-duty, standardized broadband wireless technology that handles fixed and mobile voice and data. Unlike Wi-Fi, that typically can be used only for short distances, WiMAX is a long-range technology that, depending upon the terrain, might reach as far as 30 miles. This makes it ideal for wireless IP networks that handle both data and voice. Early data shows that voice – VoIP – might well be the WiMAX ‘killer application’ in emerging markets.
For every new technology, the question always arises – what is the killer app for this technology? In other words, what application will be so highly sought after by the technology’s users that it will drive a healthy revenue stream for the service provider and ensure the long-term survivability of the technology? Not surprisingly, this debate is now raging for Worldwide Interoperability for Microwave Access, WiMAX. Considering the growing popularity of Voice over IP, VoIP, in developed and emerging markets, many believe that voice services might well emerge as the ‘killer app’ for WiMAX. The early data would seem to support this theory. Voice is a dominant service being offered in the early WiMAX deployments. In some areas, a staggering 70 per cent of WiMAX service providers are either offering voice services or using their networks to carry voice services for a partner or affiliate. WiMAX is proving itself to be an effective delivery system for voice services. Since WiMAX is an all IP-based technology, voice is translated into VoIP packets before being transmitted over the network. Is it enough for WiMAX to be good at delivering voice? Will voice alone ensure its survivability? However important voice may be as a revenue machine for operators, WiMAX system designers understand that voice is seldom, if ever, the only application on an IP network. If it were, then WiMAX would only need to be a wireless manifestation of the Public Switched Telephone Network, PSTN, delivering a constant stream of bits from one end-point to another. The PSTN was designed from its inception to carry voice, and only voice, and it still does so today. However, unlike the PSTN, IP network applications cover a wide range of voice, video, data and multi-media services, including: real-time voice calls; streaming audio and video; instant messaging; e-mail; file downloading; Internet gaming and, of course, web browsing. On the IP network, all of these traffic types are considered as ‘data’ – carried within the payload of the IP packet – but the requirements for dealing with each of them effectively can be quite different. Voice services need low end-to-end latency (network transmission delay) and predictable performance (low jitter) to give callers the same real-time experience that they have come to expect from the PSTN. Voice applications tend to need little bandwidth and tolerate errors on the link reasonably well since the human ear ‘fills in the gaps’ based on the context of the discussion. Data applications, on the other hand, have significantly different network requirements than voice. Some data applications are quite tolerant of unpredictable performance since the user may not be expecting real-time delivery anyway; email is a classic example. Other data and multimedia applications, however, require predictably high performance, but may tolerate fairly high latency conditions. Downloading multimedia files and streaming audio and video fall into these two categories. Most data tends to be fairly intolerant of link errors and can be quite bandwidth intensive. Therefore, since voice is typically not the only application on an IP network, the network needs to be smart enough to adapt to the individual requirements of each application. Even more daunting, the network needs to handle these applications simultaneously; while treating each one individually – even on the same wireless channel. The WiMAX architects paid close attention to the usage trends on other all-IP networks such as cable and DSL. Voice continues to be a growing and dominant application. Worldwide, VoIP users have grown at the staggering rate of more than one million new users each quarter since the middle of 2004. During the same time period, North America has seen a doubling of the number of VoIP users each quarter. With the proliferation of Skype, Vonage and other low cost, highly featured Internet-based calling services, these trends are likely to continue, if not increase. VoIP usage is moving to Wi-Fi in the form of Wi-Fi phones and access points with integrated VoIP SIP, Session Initiation Protocol, user agents. However, DSL, cable and Wi-Fi were not designed from the ground up to deal with the explosion in multi-services. Wireless engineers learned a lesson – Design the IP network from the start to handle multiple services, including voice, as a key revenue generating application. WiMAX addresses this challenge. To handle voice as a key application in a multi-service environment, IP networks require both technical and non-technical attributes not found in most other access networks. The early designers of WiMAX specifically built attributes into WiMAX so it could operate efficiently and effectively in this environment. These built-in attributes include an effective and flexible quality of service, QoS, regime, the ability to roll-out economically a network over a wide area, and a range of bandwidth management schemes to deliver differentiated traffic to consumers, small business and enterprises over a common platform. WiMAX for urban, rural, enterprise, SMB and residential? WiMAX can be deployed to serve virtually every user segment over wide economic and geographic spectrums. In Europe, Iberbanda deployed a 3.5 GHz WiMAX system to provide broadband access for municipalities, businesses, government offices and residential customers throughout Spain. In addition to offering network access to businesses throughout the heavily populated coastal territory of Spain and the Pyrenees, Iberbanda employs WiMAX equipment to cover Seville and other provinces in Andalusia, including Almeria and Cordoba, in the south of Spain. Iberbanda has deployed similar networks in densely populated areas like Madrid, in business and industrial areas like Guadalajara, and in the regions of the rapidly growing Mediterranean sector, including Lerida and Murcia. In the Pyrenees, Iberbanda has deployed these solutions to provide connectivity and broadband services to isolated valleys and sophisticated ski resorts alike. Urban, rural and suburban networks are all based on the same WiMAX platform, which is also used for projects with Andalusian and local and regional Mediterranean communities. Indeed, we see WiMAX operators addressing the needs of corporate users in New York City, as well residential users in the emerging economies of the Middle East and Africa. It is serving users in the open stretches of rural Montana, as well as the discrete islands of Indonesia. In each of these cases, the typical services include voice as an important application, in addition to various forms of data. WiMAX network operators are reaping the benefits of a technology that is wireless – it does not require building a wired infrastructure which often does not exist in developing or rural areas. It enables a faster and cheaper service deployment by the operator, and a more flexible management system – which translates into more affordable service costs for subscribers. Moreover, the time for deploying the service is substantially reduced. Outdoor WiMAX systems can be deployed in minutes versus the days or weeks often required to properly qualify and provision a DSL or cable line. Traditional wire line operators can offer WiMAX as a ‘fill in’ service for customers outside the central office range of DSL. The end result, rural villages that previously had no phone service – or who shared a single phone because there was no wired infrastructure, and it was too costly to build one – will have access to an affordable service connecting them via voice and data to the world. Small and medium businesses will have affordable broadband access for voice and data, making them more competitive. Voice and multi-services are predominantly provided today through a discrete WiMAX CPE, customer premises equipment, interconnected with a voice telephone adapter or Integrated Access Device, IAD, hosting plain old telephony, POTS, phones and PCs. In the near future, WiMAX CPE will be widely available with integrated POTS lines, SIP capabilities and router functions. Other advanced options will include dual mode Wi-Fi/WiMAX CPE allowing extended wireless access to Wi-Fi clients. WiMAX infrastructure is integrating into the IP Multimedia Subsystem, IMS, infrastructure to hasten the vision of seamless access to multimedia services from any access media. Secret sauce: robust QoS and intelligent bandwidth management WiMAX designers have built in two key features enabling superior voice and multi-service delivery over the IP network. They are robust quality of service, QoS, and intelligent bandwidth management. WIMAX systems vendors are implementing algorithms to very discreetly classify and prioritize traffic delivered to and from the subscriber. Advanced WiMAX systems will allow operators to tune the system for the unique characteristics of voice (low latency and jitter) – and therefore deliver toll quality and simultaneously satisfy bandwidth hungry data and streaming media applications. After the data is classified, WiMAX systems assign a delivery priority based on the classification result. Specific priorities can be set for real-time services, like voice, that requires a guaranteed data rate of near real-time access to the channel versus non real-time services like email, which requires only best effort service delivery. Priorities are provisioned and observed at both ends of the WiMAX link. WiMAX systems implemented with leading-edge QoS features will offer a distinctive advantage to operators intending to offer voice, data and multi-media services. For many small and large operators, radio spectrum is a precious and scarce resource. Therefore is it critical that spectrum is utilized economically by carrying the maximum payload both upstream – from the subscriber, and downstream – to the subscriber. Voice traffic is typically symmetric with both callers having an equal opportunity to talk. Conversely, file downloading and streaming multimedia require more bandwidth in the downstream direction allowing the subscriber to receive the data as quickly as possible. Therefore, flexible bandwidth management schemes for dealing with bursty, asymmetric, data traffic simultaneously with voice, is another key technology driving WiMAX success. WiMAX employs a Time Domain Duplexed, TDD, scheduling scheme that allows the link to be specifically tuned for the application in use. So, if a user’s primary requirement is for asymmetrical data traffic – in which the aggregate downlink traffic is exceeding the aggregate upstream traffic – TDD systems can assign more bandwidth in the downlink direction. Advanced TDD systems will dynamically adjust and synchronize the bandwidth allocation for hundreds of subscribers according to application traffic requirements. WiMAX in the morning, WiMAX in the evening, and WiMAX in the summer time Many believe that voice could be the killer app for WiMAX and there is increasing data to support this theory. However, a system that is good at carrying voice must also be good at carrying the same services delivered on today’s wired networks – voice, data and multimedia. WiMAX has been designed from the ground up for multi-service delivery with key technologies baked in. Combined with the inherent properties of a wireless system of rapid, flexible and low-cost provisioning and management, WiMAX has an opportunity to increase dramatically the availability of low-cost, high-quality voice, data and multimedia services.