IP Communications

 

This is not unlike the early days of the wireline networks, when dial-up modems and other data solutions where grafted on top of voice-centric networks. But just as the wireline networks have transformed into modern network architectures optimized around the delivery of IP packets, the wireless market is poised to undergo a similar transition.

 

In the wireless market, user demand for mobile services has grown beyond basic voice and text messaging to more sophisticated forms of broadband Internet access and multimedia services. One need only look at the affect the iPhone (News - Alert) is having on carrier’s network traffic to get an indication of the pent up demand for mobile Internet access. This demand for bandwidth is coupled with continued downward pressure on average revenue per user (ARPU), leaving mobile operators in a difficult position. Their existing networks are ill-equipped to handle the projected demand for IP-based services. Furthermore, the complex hierarchical model that is currently deployed is expensive to own and operate leading to lower margins in a highly competitive industry.

 

To address these limitations, service providers are pursuing all-IP wireless architectures that promise to reduce complexity, simplify the wireless core, and decrease service providers’ operational and capital expenses. Two technologies are especially popular:

 

 

These architectures are similar in that they leverage a flatter, all-IP network architecture with fewer nodes coupled with high-performance Orthogonal Frequency-Division Multiple Access (OFDMA) air interfaces. This streamlined architecture lowers overall deployment costs, enabling delivery of sophisticated broadband services at affordable prices while maintaining telecom operators’ gross margins. Real-time services such as voice and video are also readily handled by these new flatter architectures, as they reduce overall latency and have robust support for end-to-end Quality of Service (QoS).

 

The Access Service Gateway is emerging as the critical network component in the flatter, all-IP network. The gateway consolidates multiple functions from legacy architectures, including some functionality of the Radio Network Controller (RNC), Packet Data Serving Node (PDSN), Gateway General Support Node (GGSN), and Serving GRPS Support Node (SGSN). Called an Access Services Network (ASN) Gateway in WiMAX, or an Access Gateway in LTE, this new element knits base stations together to create a scalable, feature-rich, end-to-end network.

 

The Access Service Gateway has visibility across all subscribers and subscriber flows, and thus is the obvious point to apply intelligence to the network. Service providers can use the gateway to manage their subscribers, enable differentiated services, and optimize network resources.

 

At a minimum, the Access Service Gateway provides a number of critical functions, including subscriber authentication and addressing support, service flow authorization, mobility management, billing and accounting services, and load balancing. In addition, vendors can implement value-added features within the gateway to further enhance the network for service providers. These features can include peer-to-peer traffic management, advanced billing and charging models, granular QoS policing and shaping, advanced content management, security, backhaul optimization, and spectral optimization.

 

In early WiMAX deployments, service providers have been forced to piece together ASN Gateway functionality with little more than repurposed routers or Linux appliances that lack the performance, scalability, and wireless intelligence needed to deliver large-scale, profitable WiMAX services. As standards mature and vendors begin to introduce purpose-built ASN Gateways, it is important to consider the requirements needed to deploy successful services.

 

WiMAX and LTE networks leverage OFDMA-based air interfaces, with advanced features such as Multiple Input, Multiple Output (MIMO) and Adaptive Antenna System (AAS), that are capable of generating ten times more bandwidth than current wireless networks. As a result, mobile operators require gateway solutions that can readily accommodate this increased bandwidth. Solutions that may have been reasonable for 2G or 3G networks may not be well suited for the bandwidth demands of WiMAX and 4G.

 

Flatter, all-IP wireless networks also require gateways that support a large number of dynamic service flows with extensive per-flow processing to effectively support tiered services. These requirements can be very taxing for platforms that were not designed specifically for WiMAX or LTE. Any individual subscriber may have several active service flows, each with a unique QoS profile. Per subscriber/per flow accounting, security and QoS must be performed at line rate to ensure optimal service for customers.

 

While walled garden services have dominated in the past, service providers now must deal with increasing customer demand for access to the myriad services available on the open Internet. Unleashing the Internet upon the wireless infrastructure can certainly cause concern for some service providers. Will peer-to-peer traffic run rampant and swamp my wireless network? What about security? Service providers have traditionally controlled all the services they offer, and are concerned that by opening up their networks to third-party applications and services they run the risk of simply becoming a “dumb pipe”. As a result, they are actively exploring opportunities that enable them to monetize the Internet.

 

By deploying an intelligent core infrastructure, carriers can carefully manage this internet traffic and fully exploit monetization opportunities. For example, they can identify and manage peer-to-peer traffic so it does not overwhelm the network and degrade service quality for other users. On-the-fly identification of a range of applications and content gives service providers the control they need to manage their infrastructure and enforce network-wide traffic engineering, security, and billing policies

 

These content-management capabilities can also help provide differentiated services and enable new revenue streams. Not all peer-to-peer traffic is bad: in fact, much of this traffic carries legitimate services. Service providers can work closely with Internet content providers to enable differentiated QoS for specific applications and services, and leverage extensive accounting capabilities in the core infrastructure to provide a new class of “smart pipes.”

 

Providers can also use intelligent processing of real-time content together with subscriber profile information to create new and unique services, such as location-based ad insertion. The ability to identify unique applications and content in real-time, coupled with extensive accounting, QoS and security features, becomes a valuable tool that enables service providers to fully leverage the open Internet model and improve their bottom line.

 

Another area where the intelligent wireless core can add value is with network optimization. With visibility across all base stations and subscribers, Access Service Gateways are uniquely positioned to help manage precious resources such as backhaul capacity and spectrum. Since most of the backhaul links currently used for 3G networks do not have the bandwidth needed for next-generation broadband wireless networks, service providers want to use these links in the most efficient manner possible. By implementing compression and advanced traffic management in the Access Service Gateway, service providers can optimize use of their backhaul links, enabling more subscriber traffic across a limited amount of bandwidth.

 

Spectral resources are also a precious commodity for service providers. With a global view of subscribers and base stations, intelligent Access Service Gateways can assist with load balancing, ensuring seamless handovers and a variety of other optimizations to ensure maximum efficiency of spectral resources and a premium user experience.

 

Migrating from a primarily voice-centric hierarchical model to a flatter, all-IP based architecture reduces the complexity of the network, enabling service providers to reduce not only the amount of capital required to deploy the network but also the ongoing expenses associated with managing and operating it. The new Access Services Gateway, whether an ASN Gateway for WiMAX or an Access Gateway for LTE, is a critical component of these emerging flatter networks.

 

Due to its unique position in the network, the Access Services Gateway sees all the subscribers and their associated traffic flows. It is therefore the ideal location to deploy value-added intelligence for enabling new services, optimizing network resources, and providing advanced subscriber management. These solutions will allow carriers to expand their services capabilities and deploy large-scale, profitable WiMAX and 4G networks.