FEATURE: Utilizing QoS for premium services over WiMAX

According to a recent report by Maravedis Telecom Market Research & Analysis, the fixed broadband wireless market will exceed $2 billion globally by 2010. The promise of wireless broadband is that, regardless of where a subscriber is located or the current capabilities of the incumbent wireline service provider, services are readily available over the air. Though slow to develop, WiMAX is gaining traction as a preferred way to extend the wireline providers' service footprint cost effectively to low-density subscriber areas or as a standalone operation via wireless Internet service provider (WISP).  With WiMAX, fixed operators can readily expand to offer mobile-type applications including VoIP, while mobile operators can migrate toward multi-service broadband models as in the case of Sprint Nextel, which recently announced a nationwide rollout of WiMAX.

Without question, advanced applications will be the key competitive advantage in the wireless market at large. WiMAX supports an unparalleled list of media-rich IP applications--from broadband Internet access to instant messaging, multiplayer interactive gaming, streaming media, VoIP, video and teleconferencing and media content downloads. Following the path of fixed IP services, early WiMAX initiatives are focusing on VoIP. Success of corporations such as Vonage, Skype and a host of others have paved the way for VoIP as a serious alternative to traditional circuit switched phone service.  Most cable operators are now offering it as part of their bundled service packages as a way to attract subscribers from the telcos while simultaneously increasing ARPU.

Although VoIP has garnered worldwide attention, most still use the service only as a second line or as a convenient way to communicate PC-to-PC since unpredictable traffic congestion on the Internet severely affects performance. Unreliability has plagued the wireless market as well. Cellular phone service is still noted for dropped calls and poor coverage areas while WiFi, due to its competing access nature, at times inconveniently prevents network access or is easily interfered with by nearby devices utilizing like frequencies. Pairing VoIP with wireless would seem like a recipe for disaster; however unique to WiMAX are IEEE specifications within the air interface that ensures end-to-end service quality.

Built for Quality
WiMAX's ability to enable high-quality wireless broadband services is unparalleled. Its underlying media access control (MAC) protocol, borrowed substantively from the cable industry's DOCSIS standard, offers providers the ability to precisely manage QoS to the individual subscriber and application in real time.

WiMAX's MAC layer includes a traffic scheduler that is primarily responsible for queuing both upstream and downstream data flows by shaping the IP flows at the MAC layer with firmware located within the base station. Previous broadband wireless technologies offered only coarse prioritization capabilities. WiMAX, however, based on the core IEEE 802.16 standard, offers a menu of QoS management techniques that are available for applications to request parameterized quality of service, defined by precise allocation of bandwidth, latency and jitter specific to each service flow. Within this framework, external network elements such as a policy management platform, acting on behalf of applications and service provider policies, can direct the traffic scheduler regarding how to shape the traffic.

For VoIP data, this means that the CODEC-specific bandwidth can be scheduled with a latency that minimizes dropped packets. For real-time, high resolution streaming video, the bandwidth can be temporarily and dynamically increased-beyond the provider's statically provisioned values. While WiMAX service providers can statically provision their access networks and provide best-effort treatment to most IP data, QoS policy management technology offers them the ability to intelligently manage their network and services.

By managing the data flow specific to each application and/or content, service providers can differentiate their own walled garden services from those of third-party content providers such as Vonage or Google. Leveraging this capability, the provider not only gains the ability to further monetize the value of its underlying capital investment, but also transforms them into a mission-critical partner, particularly to the enterprise community by offering service level agreements to the most demanding and often highest margin customers.

True WiMAX service providers are uniquely positioned to not only maximize subscriber satisfaction in the face of enormous competition, but also to gain incremental revenues associated with differentiated services. To do this, they must implement a centralized approach to policy management that coordinates the performance and functionality of applications that include VoIP, video, and beyond. By intelligently managing the network, service providers can not only maximize the value of their capital investments, but also reduce operational expenses with carefully coordinated network management policies.

Jay Malin, PhD., is VP of Business Development for CableMatrix, a provider of Quality of Service (QoS) policy management solutions for the broadband industry.