By Peter J. Brown

Robust, appealing and affordable Ka-band solutions are attracting new customers thanks to a growing menu of services. Applications ranging from enterprise and government high- speed data services to consumer two-way broadband and high-definition TV (HDTV) are being provided via an increasing number of Ka-band payloads, with operators in Japan and North America leading the way.

Consumer broadband services offered by Wildblue Communications Inc. and Telesat Canada in North America attracted thousands of customers by the end of 2005 and hundreds of thousands are expected to sign up by the end of 2006. "This rate of growth would not be possible without effective network operations on a scale never before seen on satellite," says Marc Agnew, vice president, broadband systems at California-based ViaSat Inc.

According to Don Osborne, president at Advantech Satellite Networks Inc., the implementation of such techniques as DVB-S2 adaptive coding and modulation, along with adaptive carrier rates on the inbound channels, has made an enormous difference for the service providers If everything goes according to plan, enterprise customers soon will start migrating to Ka-band to access cheaper satellite terminals and more affordable bandwidth. "Ka-band satellite broadband terminals will price below $300 within a few years and will be fully capable of supporting enterprise applications with an integrated VPN product," says Agnew. "The emergence of IPTV (Internet Protocol TV) plays into Ka-band as an IP multicast service delivered over the same broadband pipe as the customer’s Internet service."

However, despite considerable enthusiasm for Ka-band in certain circles, some satellite operators remain cautious. Intelsat Ltd., for example, has invested in Wildblue and recently launched a Ka-band payload aboard the Intelsat IA-8 satellilte, but at this time, Ka-band does not play a significant role in the company’s strategy. "Intelsat’s investment in Wildblue is a very good augment to its North American business — it gives Intelsat a strategic position in the retail broadband market, allowing us to contribute to and gain from the business without being directly involved at this time," says George Giagtzoglou, Intelsat’s senior director, strategy and planning. "Intelsat will continue to look at the opportunities for this frequency, particularly in areas where constraints on Ku-band capacity exist, such as North America and Europe, and potentially in other rapid growth regions. The Ka-band configuration of IA-8 is unique as it incorporates a multi-spot design, which is suitable for applications that require high contribution bandwidth," he says.

Telesat On Top

Telesat quickly is becoming a Ka-band powerhouse, letting competitors and customers know that the right pieces are falling into place, that this is not a gamble and that Ka- band is a necessity when it comes to the future success of the satellite industry as a whole. "Telesat has pioneered the introduction of new satellite spectrum and technologies in North America and was the first to fully commercialize the Ka-frequency band with the launch of the Anik F2 satellite," says Dave Lahey, vice president, business development at Telesat, which owns and operates eight satellites. "Ka-band will play a key role as more subscribers and features are introduced over the next several years," he says.

Anik F2 — a Boeing-built, three-band satellite equipped with 38 Ka-band transponders, 32 Ku-band transponders and 24 C-band transponders — is used to provide direct-to-home TV service, televoice and data services, private networks, IPTV, and two-way, high-speed Internet services, and Telesat has more Ka-band capacity coming. Anik F3, providing both Ku- and Ka-band capacity, will be launched in the third quarter to 118.7 degrees West. In 2008, Nimiq 4 will be placed at 82 degrees West. Both satellites are Eurostar E3000s built by EADS Astrium. An even more significant increase in Ka-band bandwidth is planned in the future with the launch of Telesat’s Anik G1, which will be located at 118.7 degrees West.

Telesat’s expansive Ka-band satellite network operations depend on an ability to manage carrier monitoring across gateways. "Due to the nature of the spot beam design and the frequency reuse, the satellite architecture demands a common ground system to be widely deployed in gateways across the continent," says Lahey. "Ka-band is essential to the future for broadband via satellite. Volume is the key to achieving the economics needed to satisfy the consumer broadband market, and the huge amounts of capacity available with Ka-band spot beam satellites will enable those volumes," he says.

More Optimism From Hardware Providers

As the number of Ka-band payloads grows, the vendors of terminals and other vital ground components are seeing more reasons for optimism. However, there is still a way to go before the volume of Ka-band sales is substantial. "Our Ka-band RF (radio frequency) product volumes are still quite small today, and it does not constitute a major part of our business yet, but we are seeing growth and expect this to continue," says Ed Kevork, vice president, RF product development at Advantech AMT. There is strong demand for solid- state high power amplifiers (HPA) for powers up to 50 watts and 100 watts, he says. "Due to the high frequencies, almost all applications are for outdoors close to the hub of the antenna."

Xicom Technology Inc. also has seen increased demand for Ka-band high power amplifiers throughout the last several years in both the commercial and the military markets, according to Travis Stewart, Xicom’s director of engineering. "One of the most significant advantages of operating in Ka-band is that it offers additional operational bandwidth, which gives operators more capacity. The high capacity in Ka-band drives the requirement for greater linear power," says Stewart, who describes the output power of the HPAs as increasing from 120 watts to greater than 250 watts throughout the last five years. "The integration of block up-converters into HPAs is common in C-band and Ku-band, and there is an increase in requests to integrate these devices into the Ka-band HPAs, too," says Stewart. "The advantage is decreased system integration complexity, reduced system cost, and a direct L-band input into the HPA."

Besides lower cost of RF products and terminal hardware, service providers want a system that scales easily and supports automated subscriber provisioning, facilitates subscriber and traffic management, and allows unmanned operation of satellite gateways, Agnew says. "There is no significant difference in network management of Ku-band versus Ka- band systems. Spot beam Ka-band satellites enable networks that can exceed the size and scale of local cable or [digital subscriber line] networks and require commensurate network management systems," he says.

According to Max d’Oreye, Newtec’s director of business development, there are significant network management challenges due to such things as adaptive coding and modulation functionality, a complex hub infrastructure and complex service level agreement management stemming from the real-time monitoring of the receive conditions at all the terminals, as well as data traffic bandwidth variability. Newtec products include end-to-end solutions like 2Waysat and a satellite triple-play system dubbed Sat3play. However, customers are requesting Ku-band solutions due to the high cost and low availability of Ka-band capacity in Europe in particular, where Ka-band has never really evolved into a viable commercial option. "To access the consumer market on a larger scale, we need more satellites with Ka-band spot beams, such as Anik F2," says d’Oreye.

The failure of a Ka-band satellite also would leave the user without much back-up capacity at his disposal, says Giagtzoglou. "In the United States specifically, Ka-band capacity is better positioned to serve specific parts of the market, such as large VSAT networks for Internet services or consumer broadband services. This puts less pressure on Ku-band," he says.

Know How Applications Will Perform

Although the new generation of Ka-band systems is built to support higher bandwidth at lower cost, there is no way to avoide problems associated with latency, the half-second delay created when signals travel to and from the satellite, says DC Palter, president of California-based Apposite Technologies Inc., which develops satellite simulators and network test equipment. "Various acceleration technologies mitigate the impact of that delay on protocols and some applications, but for anything that depends on real-time communications, particularly voice and Internet gaming, the satellite delay will be noticeable," he says. "The only way to know how applications will perform under high latency conditions is to test them."

A team at the Center for Satellite & Hybrid Communication Networks, a NASA-funded organization within the University of Maryland’s Institute for Systems Research, is performing modeling and simulation studies on power allocation in multiple spot beam satellite communication systems. One of the team’s objective is to identify ways to optimize network performance and traffic aspects of the network. The team found that for some users in deep fade periods, full recovery is not possible within reasonable session times even if a forward error correction code capable of generating many encoding packets is used. It is better for the transport protocol to drop the connection to these users rather than wasting system resources with multiple connection attempts. "Our focus, in a follow-up work, was on how a reliable channel condition value can be obtained for a spot beam without asking or collecting periodic feedback from every active user, as this would place a heavy burden on the limited or scarce network resources in the return path, either a satellite return channel or a terrestrial dial-up return channel," says Gun Akkor, a staff scientist in Patton Electronics Co.’s engineering department,

Testing live satellite links in order to troubleshoot problems and optimize performance is time-consuming and expensive, whereas simulators offer a simple and efficient alternative way to test systems in the lab under a variety of conditions. For example, consider the possible combination of a Ka-band or Ku-band satellite link with a wireless Wi- Fi last-mile solution. Palter recently ran some performance tests on this type of deployment using Apposite’s Linktropy 4500, a hardware-based simulator. A 10-megabyte file took approximately 100 seconds to download directly via satellite. Using a Wi-Fi connection plugged directly into the terrestrial Internet, the same file downloaded in about 90 seconds. "But here is the unfortunate surprise: Combining the packet loss of Wi-Fi with the latency of satellite caused the same file to take nearly 900 seconds to download," he says. "And using Windows file sharing instead of FTP caused the download to take nearly 1,200 seconds. The implication is that it is critical to test the whole end-to-end network. Testing individual sections may not show important interactions between the component links."

Not Just A Consumer Play

New Ka-band markets, like digital signage, are still works in progress and not yet on the fast track like applications such as direct broadcast satellite Ka-band deployments for HDTV local into local broadcasting or the Wildblue consumer broadband initiative. Newtec is preparing the delivery of a Ka-band network to Arqiva for multicast delivery of digital signage information which can also be used to distribute digital cinema, says d’Oreye.

"Satellite news gathering is where the advantages of Ka-band are expected to yield an immediate result, but questions about reliability are having an effect," says Osborne. "Today, there is some high-end demand for satellite news gathering applications in Ka-band," he says, adding that enterprise applications suffer from the perception that Ka-band is unreliable due to rain fade. "Although this technology has been proven reliable, this perception remains," he says.

Ka-band research continues. In addition to the work being done at the University of Maryland, Japan’s Wideband Internetworking Engineering Test and Demonstration Satellite project is moving ahead. The spacecraft will be equipped with a Ka-band active phased array antenna, a multibeam antenna and a high-power multi-port amplifier. Although the program was put on hold in 2004, a launch in 2007 is a strong possibility, says an official at the Japanese Ministry of Internal Affairs and Communications.

Although we may be ready to declare that the first phase of the Ka-band revolution is officially over, it still is a bit too early to proclaim that profitable Ka-band operations are a reality.

Peter Brown Is Via Satellite’s Senior Multimedia and Homeland Security editor.