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Earth Stations: More Than Transport

By | June 10, 2001

      By Peter J. Brown

      Last month we talked about how earth stations are in a state of flux with the projected growth in large facilities–Standard A earth stations–slowing considerably. At the same time, the growing capabilities of today’s much smaller earth stations are helping redefine satellite-based networking.

      Indeed, the topology of satellite networks–mesh versus star–is not changing radically. One element propelling this new industry model is the impressive list of features that stand out on the network management side. Whether found in a specific hub or gateway at the center of the star, or as the designated network management site in a mesh configuration, these smaller earth stations are the ideal representatives of this leap forward, both in terms of technology, and networking prowess.

      We will examine a couple of examples of how supercharged satellite network control platforms represent the cutting edge in this regard.

      Of course, enhancements in power amplifiers and other earth station components are ensuring that customers enjoy a wide range of cost-effective options in an increasingly data- centric environment.

      The Quest For Better Space Segment Utilization

      With all the mounting momentum behind Ka-band comes even more emphasis on achieving greater performance–higher data rates and faster throughput–from existing Ku-band networks.

      A powerful pairing of companies in the past year that tracks with this theme involves Norcross, GA-based Viasat Satellite Networks, which resulted from the acquisition of the VSAT group at Scientific-Atlanta Inc. by CA-based Viasat last year. Viasat has scored well in the Ka-band sector with recently announced contracts involving Wildblue and Astrolink. While Viasat’s Ka-band gateways for Astrolink will take some time to develop, the hubs for Viasat’s new ArcLight system, with its star topology, are scheduled to emerge later this year.

      With the ArcLight subscriber terminal not only serving as an advanced IP router, but also with a star network which can be expanded to as many as 32,000 user terminals per hub, network management is a key concern. Using a solution based on Simple Network Management Protocol (SNMP), and HP OpenView, the ArcLight Executive Network Management System (E- NMS)–based on Sun Microsystem’s Solaris operating system provided in a Sun SPARC workstation–allows for complete control of the system including addressable software upgrades to either the entire base of ArcLight terminals, or a select few.

      E-NMS not only performs all of its monitoring and control (M&C) operations in partitioned real-time autonomous and non-real-time tiers, but it also allows a single operator to oversee the allocation of network capacity including guaranteed bandwidth and the A-PCMA-driven (Asymmetric Paired Carrier Multiple Access) outbound feed via the DVB multi- protocol encapsulator (MPE). In this manner, the operator can establish service provision policies and operating parameters for the entire network as well as for individual terminals or select clusters of users.

      “With its DVB outbound carrier, ArcLight opens up all kinds of possibilities in the area of data-centric networking. One example is a cost-effective way to pursue a hybrid BTV/data application,” says Stephen Spengler, Viasat’s vice president of worldwide sales.

      As an earth station, the ArcLight hub will transmit the DVB-S outbound carriers at up to 45 Mbps using QPSK modulation and use a combination A-PCMA technique for inbound and outbound traffic on the same frequency with spread spectrum-based Code Reuse Multiple Access (CRMA) for the return channel as well.

      “ArcLight will initially be available in a Ku-band configuration. It is a successor to S-A’s SkyRelay system,” says Spengler. “With the outbound and return channels using the same amount of physical bandwidth, users enjoy dramatically improved operating costs.”

      Full Mesh Frame Relay: Getting Started On A Budget

      Despite the collective fascination with Internet Protocol (IP)-based traffic over packet switched networks, the circuit switched world is not suddenly coming to an end. Supporting existing circuit switched services, while adding packet switched services that support legacy protocols is a reality in the international market today. Frame Relay (FRAD) may deserve a second look by anyone seeking to deliver a guaranteed Quality of Service (QoS) while delivering a lower cost migration route to an exclusively packet switched environment.

      “Overall, we have been quite surprised by the demand for a FRAD interface. Besides offering easy terrestrial interfacing, the fact that all the inexpensive services which can be built on top of a FRAD are a reality–and that they are field-proven at an attractive price–is a big plus,” says Ron Mankarious, Quebec-based NSI’s vice president of marketing.

      “We have set up this FRAD interface to our VSAT unit at 2 Mbps. Along with the QoS dimension, our StreamView Network Management System gives users the option to change the burst rate, and connectivity between any site all in software from a centralized location,” he adds.

      In order to provide the most user-friendly environment in a hubless configuration, NSI created StreamView which not only exemplifies how far dynamic bandwidth management has come, but also adds to the overall attraction of a FRAD-based solution. StreamView uses Sun Microsystems’ Solaris operating system provided in a Sun UltraSPARC-driven workstation. The fact that the StreamView application server site does not need to include the bandwidth-on-demand (BOD) server underscores the flexibility of this networking option where real-time traffic analysis is a must.

      The StreamView server application tracks and converts a long list of DAMA-based activities into a series of coherent reports as this migration from an entirely circuit switched universe to one where packet switched service is part of the routine.

      Among other things, StreamView allows for alternative workflow options by supporting multiple operators with partitioning and restrictions on access to specific network management functions. And so, it is possible to have a pair of operators with one enjoying full and unrestricted access to the system for administrative and diagnostic purposes, while another simply serves as a network monitor.

      While FRAD has been around for years, there are some other exciting new twists. Added flexibility in the form of new hub configurations along with advanced bundling concepts where high speed fixed access is combined with the lower speed mobile access in a single integrated package is opening more and more doors.

      NSI is working with Norway-based Telenor, for example, in Asia and Africa on a unified hub deployment strategy for the United Nations. Using Intelsat and Inmarsat satellite capacity, three UN agencies including UNICEF, UNDP and UNOPS have now deployed their fixed and mobile terminals such as Mini-M’s together through a single facility, the Telenor teleport in Nittedal, Norway. The UN is billed on a uniform reduced rate basis, instead of paying a higher premium for mobile access.

      “We connect these three UN agencies throughout Africa and Asia, either in a star configuration back to the UN headquarters in New York City, or in a mesh fashion with their counterparts in the region. At the same time, all Internet traffic is routed directly to our gateway in Norway,” says Auden Moen, technical director at Telenor Slovakia in Brataslavia. “This is a DAMA platform which gives the customers a cost effective communication service between the field offices, and the headquarters in New York, and between different field offices as well.”

      Amplifiers Go ODU

      As the Ka-band sector readies for its service launch in North America, the power amplifier vendors are well aware of the need to reduce waveguide losses in the 30 GHz band. Santa Clara, CA-based Xicom Technology has developed a novel air-cooled ODU version of its Extended Interaction Klystron (EIK) amplifier for Viasat Inc., which is supplying gateways to Astrolink. Xicom is also supplying High Powered Amplifiers (HPA’s) to Andrew Corp., which is providing gateways for CO-based Wildblue Communications.

      “Ka-band is great for tube-based amplifiers because they deliver high power over a broad bandwidth. There is a need for a lot more headroom in the power amplifier due to the tremendous atmospheric losses that are present at 30 GHz,” says Colin Eastment, Xicom Technology’s marketing manager, who adds that customers are requesting broadband amplifiers due to the uncertainties surrounding Ka-band-related international frequency coordination.

      “With a Travelling Wave Tube Amplifier (TWTA) at 100 W out today, you can get up to 3.5 Hz. At higher powers, bandwidth is sacrificed, but we are aiming for instantaneous bandwidth approaching 1 Hz at output powers of 500 W,” Eastment adds. “Eventually we may see CPA’s with power in the 2 kW range with instantaneous bandwidths over 150 MHz.”

      Trends to watch include higher linear power that translates into higher data rates with multi-carrier applications. At the same time, fiber optic inter-facility links are replacing coaxial cable for easier transmission equipment re-deployment including more and more hardware mounted on the antenna.

      The Pursuit Of Partnerships

      While this pair of articles has focused primarily on how the satellite ground segment vendors are keeping pace with a changing marketplace from the standpoint of technology, the companies themselves are also going through a transition. Last year, for example, Happauge, NY-based Miteq Inc. acquired MCL Inc. In doing so, Miteq’s strengths in microwave components, integrated assemblies and earth station equipment is augmented by MCL’s amplifier product lineup.

      “The purchase of MCL further enhances Miteq’s ability to support the satcom community by offering ever expanding product lines,” says Chris Alfenito, Miteq’s director of sales for satcom products. “Their strengths are in klystrons and TWTA’s. We are continuing to develop SSPA expertise as well, and we expect to enter this market within the year.”

      Alfenito indicates that while he agrees that the Standard A earth station market is softening considerably–especially in Europe and the United States–the demand for new TWTA and klystron amplifier products–indoor and outdoor–is quite strong. Signal processing and power control elements are also in demand where facility upgrades are underway.

      “We have taken advantage of embedded microtechnology and digital signal processors (DSP’s) to dramatically reduce the price of our uplink power controls which allow users to work through rain fade scenarios with automatic power correction mechanisms,” Alfenito says.

      Miteq’s single band and multi-band synthesized converters such as the 9600 series are continually evolving in incremental steps, according to Alfenito.

      “We are awaiting the next generation of DSP and associated integrated circuit chips from Texas Instrument and National Semiconductor. Besides, it is really the advances in baseband equipment, and signal traffic that define the requirements of the converters,” Alfenito says. “The trend in synthesized converters involves going from 70 MHz or 140 MHz IF directly to RF. And eventually, fixed frequency block converters will displace synthesized converters.”

      Added Ammunition For ATM

      While adding Voice over IP (VoIP) as a value add to a broader data stream appears to be attracting considerable attention, not everyone is ready to board the VoIP bus, not yet anyway. Charles Reese, vice president of sales and marketing at DNE Technologies in Wallingford, CT, indicates that DNE is familiar with VoIP, but still prefers Asynchronous Transfer Mode (ATM)-based satellite networking for voice, data, and video.

      “With VoIP, there are a lot of issues that need to be addressed such as overhead and network management. With VoIP today, you encounter a lot of proprietary standards whereas with ATM, you are working with a totally open standard,” says Reese, adding that voice over ATM is much more efficient in terms of overhead for voice, and that whereas ATM involves approximately 11 percent, IP involves about 18 percent.

      DNE has focused on ATM concentrators, DCX voice compression multiplexers, and, voice and data multiplexers, including the SatPlex/2 and SPX 2000 series. The DTX, a 1RU version of SatPlex/2, which will be ideal for flyaway applications, is due out later this year. It will include routing and Web-based management features.

      These TDM architecture-based products offer several different data modes. For example, both the SatPlex/2 and SPX 2000 allow users to connect to satellite modems using EIA-530 synchronous data ports in both equi-rate, simplex and asymmetric data modes with data rates from 9.6 kbps up to 1,920 kbps.

      “Our strategy is that TDM offers clear throughput advantages for carrying voice and data traffic at under 64 kbps. Otherwise, our broadband strategy rests with ATM,” says Reese.

      The U.S. military has selected ATM as the core of their data networking, and is currently evaluating the integration of ATM over bent pipe satellites into their operational networks, according to Reese. DNE is a major supplier of ATM concentrators to the U.S. military, and has become intimately familiar with ATM while studying these transition issues. While ATM is often highlighted for its QoS dimension, there are other reasons why DNE is an ATM fan.

      “The satellite-based ATM platforms really met expectations, while allowing both for interoperability for all of their legacy peripherals, and the ability to handle bursts superbly,” Reese says. “With our products, satellite service providers and PSTN operators can take advantage of forward error correction (FEC), and then offer multiple classes of service over ATM which gives the service provider a lot of control over how voice is packetized, among other things.”

      Antenna Magic: Empowering Every Business Model

      There are lots of ways to pursue a satellite-based strategy, and the antenna manufacturing sector is striving to guarantee that every earth station is outfitted with the best performing antenna produced in the most efficient fashion possible.

      “The consolidation of antenna system components is a major contributing factor when it comes to cost-effectively producing smaller earth stations in high volume,” says George Jusaites, director of commercial satellite products at Channel Master LLC in Smithfield, NC.

      “This includes molding-in functional design features into the fiberglass reflector which can eliminate additional metal components, integrating block up-converters and LNBs into transceivers, and the integration of waveguide components,” he adds. “Furthermore, by designing the entire outdoor portion of the terminal as a complete set of matched system components, this not only optimizes performance, but also eliminates costly interfaces. Channel Master sees this as the way of future VSATs, especially at Ka-band.”

      The elimination of components that require additional handling, assembly and tuning is not only speeding up the manufacturing process, but it is also minimizing installation times in the field.

      “The pre-assembly of the antenna system components, such as the mount and RF units, shortens the installation time, while serving the additional functions of maintaining quality control and containing costs,” says Jusaites.

      Jackson, MI-based Eagle Communications is well on its way to attaining ISO and Intelsat certification for its line of 3.7 to 4.5 meter antennas with a sense that the transmission market is still quite wide open.

      “Our focus is cable headends which need transmit/receive antennas. We are also making lots of inroads with our plastic cable junction boxes that offer adequate size and adjustability and expandability for splitters, multi-switches, and grounding elements,” says Wendy Berry, Eagle’s senior vice president.

      The different ways in which satellite ground segment equipment can be plugged into the residence or facility in question often gets overlooked. Berry indicates that Eagle is providing one-box enclosures or single demarcation point solutions as well as on site installation services for its products in order to effectively transform itself into a one- stop shop.

      At the same time, holding surfaces to within 7/1000 of an inch for .75 and .95-meter antennas during fabrication is the subject of a recent patent obtained by Eagle with another patent issuance expected shortly.

      Earth Stations Keep Evolving

      New and enhanced products have always been evolving in the earth station sector, and present day initiatives continue to excite the imaginations of vendors and customers alike. Take what Chuck Brewer, president and CEO of Broadsat Communications Inc. in Stillwater, OK, shared with us back in April after he had just been issued patent #6208626 entitled, “Real-time Satellite Communication with Separate Control and Data Paths.”

      What Broadsat is addressing is the fact that when a terrestrial T1 backbone connection is purchased, it is sold with full bandwidth available, whether the network loading uses it or not. And when a dozen or more users start videoconferencing, gaming and/or download MP3s, the normal network load can increase by a factor of four to five.

      So rather than purchasing additional expensive T1 lines to meet the peak loads for broadband customers, Broadsat recommends an alternative, the provisioning of backbone bandwidth requirements incrementally as required to meet additional peak network loads via a two-way Backbone Anywhere earth station consisting of a C-band receive-only DVB system for inbound data traffic, and a separate C-band or Ku-band antenna serving as a control and return path uplink.

      “Broadsat’s Backbone Anywhere solves many problems that currently impact all tier three to four communities. Tier three and four communities are those locations within the United States that have less than 30,000 people within a 30-mile radius. Last mile connections to the home, office or business can be via a wireless broadband hub and/or a DSL type 101 circuit if a local ILEC central office is near,” says Brewer. Backbone Anywhere with a wireless hub can provide broadband connections without the local ILEC.

      If line of site connections are impossible, telco capacity leased from the local ILEC will be used. By splitting the control path from data transmission paths, this solution empowers the service provider, while eliminating headaches at the same time. In addition, using C-band satellite space segment whenever possible also reduces costs significantly.

      “This technology also allows for data paths to be switched from larger data channels to smaller data channels. Switching matches the data transmission load to the size of a specific channel on a satellite. Switching maximizes the bandwidth utilization of BroadSat’s purchased satellite space segment,” Brewer says.

      “All signal control generation is performed in a deterministic manner, thus enabling real-time or critical events to be dealt with on an application by application basis. This capability linked with non-fixed size data pipes makes it unique,” he adds.

      There will be ample opportunity for the entire satellite ground equipment sector to ease over $20 billion in annual sales threshold by the end of this year. That is assuming the Satellite Industry Association’s projection of better than 10 percent growth on more than $17 billion in sector sales turns into a reality again. And with all the small companies out there leading the way, the possibilities appear endless.

      Peter J. Brown is Via Satellite’s Senior Multimedia Editor. He lives on Mount Desert Island, ME

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