Posted 10/2000
Network Solutions
Broadband Wireless for Biz:
Rumblings
INFRASTRUCTURE MOVES SUGGEST ROLLOUTS
NEARING
By Fred Dawson
At long last the use of point-to-multipoint (PMP) fixed wireless technology to deliver high-speed data services commercially has begun in earnest, but to call it a wave of rollouts would be an exaggeration.
Notwithstanding the fact that the wireless broadband operators with big footprints at most of the major spectrum tiers, including WorldCom Inc. (www.wcom.com), Sprint Corp. (www.sprint.com), NEXTLINK Communications Inc. (www.nextlink.com), Teligent Inc. (www.teligent.com) and, in Canada, MaxLink Communications Inc. (www.maxlink.com), are now delivering PMP services, it all adds up to only a slight ripple in the broadband services picture at this point. How fast the momentum builds to significant proportions will depend on many factors, some related to the state of the technology itself, some to the market acceptance of such technology, and some to where the sweet spots in demand for broadband services are to be found in the year ahead.
NEXTLINK, for example, the largest holder of local multipoint distribution service (LMDS) spectrum, has chosen Nortel Networks Corp. (www.nortelnetworks.com) to supply its initial rollouts of PMP services, now expected to hit 10 markets by year's end, according to Bill Noteboom, marketing manager for broadband wireless access at Nortel. But, he acknowledges, nearly a half year after NEXTLINK's announcement that it had selected Nortel, the network services provider--which is using a variety of local access means to reach its targeted small to medium-sized business (SMB) market base--has yet to follow up with an announcement of commercial launches.
"Some of the 10 markets are deployed, at least in part, but they haven't got to all of them yet," Noteboom says.
Initially, Robustness
NEXTLINK's initial deployments involve use of Nortel's Reunion version 1.2 product, a frequency division multiple access (FDMA) system, but the carrier intends to move to version 1.3, a more advanced time division multiple access (TDMA) system, using the same installed base of transmitters as well as new transmitters as it continues to expand its PMP footprint. While FDMA systems offer a robust means of delivering separate channel streams of voice and data, the future belongs to TDMA systems that can support dynamic allocations of bandwidth and mixing of data and traditional digital voice signals within a single channel to serve multiple end users in a targeted building.
Source: Adaptive Broadband Corp. (www.adaptivebroadband.com)
NEXTLINK, which began operations as a wireline CLEC focusing on delivering high-volume voice links to businesses over fiber rings in major metro areas, is now positioning itself to be a big player in commercial data services. Founded by cellular pioneer Craig McCaw and various partners, the company currently offers services in 49 markets and holds LMDS licenses covering 95 percent of the population in the top 30 U.S. markets. The company also is acquiring exclusive rights to fiber links in building an IP-centric backbone that will connect over 50 cities in the United States and Canada by the end of 2001, with various segments turning on throughout this year and next, officials say.
"Now we're pushing ahead with true broadband services, and LMDS is becoming more of a linchpin to our service strategy," says NEXTLINK CTO Doug Carter. "Data is going to be a big piece of our business."
Carter notes NEXTLINK's recent $2.54 billion acquisition of Tier 1 ISP Concentric Networks gives NEXTLINK the service provisioning and management skills that go beyond pure transport to all the varieties of hosted applications and support for business-to-business, as well as e-commerce services that are the hot buttons in today's commercial marketplace. In NEXTLINK's strategy, PMP LMDS is ideally suited for serving customers who are looking for broadband services in the 10mbps range, while the firm is using DSL as its primary mode for serving customers at 2mbps or lower speeds and point-to-point LMDS for the high-end customers who are looking for connectivity at the 100mbps level, Carter says.
The key question is how soon NEXTLINK will find the Nortel TDMA or other systems that outperform the more rudimentary FDMA approach to be network-ready by its rigorous standards. "Nortel had the most stable point-to-multipoint equipment along with the highest level of functionality and best cost parameters in a stable system at the present time, which are the primary things we're looking for," Carter says. "There are other vendor options with very appealing architectures and better cost points that we're looking at with the expectation that we'll choose a second point-to-multipoint vendor and another point-to-point supplier before the year is out."
'Hardened' Technology
Nortel, like other wireless broadband vendors, points to initial rollouts of TDMA systems in other countries as proof that the technology has become "hardened" for commercial deployments. "We're selling TDMA systems, including one in Portugal and one in Argentina, which we can talk about publicly, and others that we can't talk about yet," Noteboom says.
Despite the slow start in PMP services, there is reason to believe that, starting next year, the rollout ripple now under way will become the wave that some vendors and their customers have claimed is already under way. Recent statements at industry forums to the effect that "2000 is the year of broadband wireless access" may thus be only a bit off the mark.
One of NEXTLINK's major competitors among wireless broadband providers, Teligent Inc. (www.teligent.com) is about to make a similar move with respect to breaking out of what has been a limited use of PMP technology in several markets to a nationwide rollout, using licenses it has acquired at the 24 GHz spectrum tier. The company hopes to begin this phase of its expansion shortly, says Steve White, vice president of sales for the company's operations in Louisiana and Texas.
Source: Adaptive Broadband Corp. (www.adaptivebroadband.com)
"Right now, that's the plan, but we won't know for sure until things get rolling," White says. "There's still a lot of testing going on in the vendor selection process."
With only 4 percent of some 760,000 office buildings nationwide now connected to fiber, the opportunity for delivering broadband access via wireless networks remains huge, White says. "We see revenues from fixed wireless services going from $300 million in 1999 to over $5 billion in 2003," he notes.
Indeed, expectations are high within the vendor community that the moment has finally arrived for a payoff after years of intensive efforts to overcome the barriers to delivering mission-critical services over cost-effective PMP networks in the high-frequency zones used by NEXTLINK, Teligent and other providers. "Prior to this generation of broadband wireless access technology, the industry didn't have the technology platform it needed to deliver voice as well as data, which is what the market wants," says Cynthia Hillery, vice president of marketing at Netro Corp. (www.netro-corp.com), a San Jose, Calif.-based supplier of PMP access equipment. "Now we've stepped beyond those limitations and are seeing preparations for service launches under way worldwide, including in the U.S."
Meeting Market Needs
Netro, with eight commercial pilot launches and over 30 trials of its PMP systems in play outside the United States, uses a combination of TDMA multiplexing of signals into ATM cells and a proprietary media access control (MAC) layer system to manage time slots in a way that meets market needs for dynamic allocation of bandwidth, Hillery explains. "TDMA is a hardened technology that is winning market confidence worldwide," she says.
She won't get any argument from rivals like Alcatel (www.alcatel.com) who are betting on other approaches to combining ATM and TDMA to achieve the QoS, robustness and dynamic flexibility today's market requires for broadband services. "We have shipped over 500 [base station] sectors of TDMA systems globally; we're in a heck of a trajectory now," says Tony Jenkins, assistant vice president for wireless product management at the wireless broadband unit that Alcatel acquired with its purchase of Newbridge Networks Corp. earlier this year.
Alcatel, which holds the contract won by Newbridge for buildout of a nationwide LMDS network in Belgium by British Telecom subsidiary BT Belgium (www.bt.be), has taken pains to integrate wireless broadband access capabilities into its multiplatform edge switches to support the needs of major U.S. carriers like WorldCom, Sprint and NEXTLINK for efficient means of operating over a mix of wireline and wireless local access links, Jenkins notes. "Dynamic bandwidth allocation and multiplatform access are realities of product being shipped today," he says.
Ironically, one of the factors fueling this optimism is the success of the cable industry's high-speed data access system, known as DOCSIS (data over cable system interface specification), which is designed to support shared access to a radio frequency (RF) stream in the hybrid fiber coaxial networking environment, but which also can be used for shared RF access over fixed wireless. Broadcom Corp. (www.broadcom.com), the leading supplier of DOCSIS chips, has launched an initiative designed to deliver "DOCSIS Plus" chips to the wireless broadband industry as well, and other suppliers are following suit. As a result, several systems vendors are relying on the DOCSIS MAC and other elements of the cable standard as they move to TDMA-based versions of their products. This includes Nortel, ADC Telecommunications Inc. (www.adc.com), Cisco Systems Inc. (www.cisco.com) and Vyyo Inc. (www.vyyo.com).
At Any Spectrum Tier
In the case of Vyyo, which is the former wireless technology firm Phasecom Inc., the company's new PMP system using DOCSIS Plus will operate at any spectrum tier, from the ultra high frequency (UHF) band all the way to 30 GHz, says Eric Wilson, vice president of systems management at Vyyo. "Our architecture takes advantage of the data side access and QoS management capabilities of DOCSIS while adding enhancements to optimize the system for wireless," Wilson says, noting that the system operates in native packet formats downstream while using TDM for return transport. The core of the system is a base station chassis with plug-in space for six modules supporting multiple configurations of down and upstream transmission capacity, which will soon include provision for 16 and 64 quadrature amplitude modulation (QAM) as well as quadrature phase shift key (QPSK), he notes.
The company also is working on adding new levels of flexibility to the system by providing for dynamic allocation of bandwidth across the various subchannels of a 6 MHz channel, Wilson says. By using the sectorization capabilities of Vyyo's transmitter system operators can allocate multiple shared usage channels, effectively doubling capacity, he adds.
"If you reuse the frequency over five channels pointing in opposite directions in the north and south sectors and five channels in the east and west sectors, you are supporting the equivalent of 20 channels of capacity from a single transmitter," Wilson says. Vyyo also has taken steps to combine and equalize multipath reflections to bring the microreflection time gaps to within the tolerance levels of the DOCSIS wireline environment, which must be on the order of one to two microseconds vs. the typical eight to 10 encountered in the wireless domain, he adds.
"Being DOCSIS compatible allows us to take advantage of the inherent data and voice over IP capabilities," Wilson notes, adding that the firm would be compliant with the newest version of DOCSIS 1.1, with gear it plans to ship three to four months from now.
Counting on DOCSIS
ADC, too, is counting on the DOCSIS platform to enhance the capabilities of fixed wireless, in this case the multichannel multipoint distribution system (MMDS) product line that the company is supplying to Sprint and WorldCom. ADC's Axity system is designed to operate in a single-transmitter or multitransmitter (cellular) network array and is compatible with the evolving air interface solutions endorsed by the Wireless DSL Consortium www.wdslconsortium.com), notes John Frederick, vice president of ADC's wireless access division.
"One of the advantages of using DOCSIS Plus is it allows you to operate at different modulation rates, where you can adjust dynamically to conditions even within a single cell sector," Frederick says. "Part of the migration path we're following is that we'll also be borrowing the fragmentation capabilities of DOCSIS 1.1 to be better able to guarantee quality of service to end users."
Fragmentation involves the breaking of packets down into uniform cells, in a fashion analogous to ATM but in smaller byte sequences so as to eliminate the bandwidth waste that occurs when bytes are left unused in ATM cells because of the incompatibilities between packet and cell sizes. The technique is designed to support VoIP in cable networks and will do the same thing for MMDS, Frederick says.
"The platform can inherently address both data and voice, which will be a killer application for MMDS," he adds.
WorldCom is testing the ADC system in Boston, along with Cisco's and other vendors' systems, and has tests under way in Dallas as well. Sprint is using elements of the ADC system in its core transmitter base stations for the initial launch of commercial two-way MMDS services in Phoenix and Tucson, Ariz., in conjunction with other network elements from California Amplifier Inc. (www.calamp.com) and Hybrid Networks Inc. (www.hybrid.com), Frederick notes. "We also have the full Axity system in trial with Sprint," he adds.
Both Sprint and WorldCom have applied for two-way MMDS licenses across their vast fixed wireless footprints, now that the FCC has finally opened the door to such applications. The commission had been expected to act a year ago but held off because the feedback from the market was that the technology wasn't ready to support the types of services these and other carriers had in mind.
Goal: Half Up by Year End
Now, with things going "really great in Phoenix and Tucson," according to Sprint spokesman Russ Robinson, the carrier is preparing to launch two-way services in Colorado Springs, Colo.; Detroit; and parts of California and Texas with the goal of being operational in a dozen or so of the 25 markets covered in the FCC submission by year's end. "We're sticking with existing suppliers at this point, but we're continuing to look at other options for future launches," he says.
Sprint intends to go after the residential and SMB markets for high-speed data using both MMDS and DSL in whatever combinations are appropriate for the customer and market conditions, Robinson notes. While voice over MMDS may be a year away, eventually the carrier would like to be able to offer the same package of services regardless of the platform, he adds. Sprint is already offering VoDSL commercially in a handful of its markets.
The carrier also is weighing what to do about the entertainment services side of its MMDS bundle, including whether to go to digital channels or to shift toward a more web-centric mix of services tied to high-speed streaming and other technologies. "That's something we're taking a hard look at right now," Robinson says, noting that the company has dropped some analog TV channels in Phoenix and Tucson in order to free up bandwidth for data services.
WorldCom, with heavy concentrations of MMDS licenses in the eastern half of the United States as well as in some parts of the West, where Sprint is especially strong, is focusing preparations for its use of MMDS on the SMB side, with multi-dwelling residential units also figuring into the calculation, says Michael Barnes, director of product management and development for the carrier's wireless solutions group. "We've already begun offering two-way services in Jackson [Miss.] and will soon be launching in Baton Rouge [La.] and Memphis [Tenn.]," he says, noting that the company will be using available upstream capacity in adjacent wireless communications service (MCS) and multipoint distribution system (MDS) while it awaits FCC approval of its applications to operate two-way MMDS in about 60 markets.
Avoids Distance Limit
WorldCom sees fixed wireless as complementary to DSL and other access means, depending on customer needs, Barnes says. For example, when it comes to offering voice or frame relay, DSL is probably the better option, although he doesn't rule out eventual use of MMDS for voice as well. But the major strengths for wireless in WorldCom's strategy lie in the fact that it gives WorldCom a fully-owned facilities base to work from, meaning it can deploy services faster, and the wireless service is not constrained by the 18,000-foot distance limit of DSL.
"We're very much a value-added provider," Barnes says. That means the company intends to use wireless as well as other access means to support e-commerce and hosted applications. "We definitely feel wireless is robust enough to deliver a full menu of integrated services," he adds.
But it remains to be seen whether the mainstream methods of delivering signals over the air will meet such requirements. Cisco, along with Broadcom, is betting that something better than the existing QAM and QPSK approaches will be needed and so have committed themselves to delivering a solution based on a new type of modulation technology known as "VOFDM" (vector orthogonal frequency division multiplexing), which was developed by Clarity Wireless, a company Cisco acquired four years ago.
Cisco contends carriers need something better than existing methods that will improve coverage by reducing line-of-sight and interference barriers, even if it means giving up the cost efficiencies associated with the mass production base for chips developed in the QAM and QPSK domains. Other companies signing on with the initiative include Motorola Inc. (www.motorola.com), Samsung Corp. (www.samsungcorp.com), Texas Instruments Inc. (www.ti.com), Bechtel Group Inc. (www.bechtel.com), Pace Micro Technology plc (www.pacemicro.com), Toshiba Corp. (www.toshiba.com), Electronic Data Systems Corp. (www.eds.com) and KPMG Consulting (www.kpmgconsulting.com).
VOFDM is designed to maximize coverage by overcoming line-of-sight barriers via spatial diversity, which applies a dual-feed antenna receiver at the end-user premises to capture incoming signals from diverse paths and combine them to achieve the highest possible signal-to-noise level, notes Steve Smith, director of marketing for broadband wireless at Cisco. By combining relatively weak reflected signals, the system delivers an output to the user that is on par with the quality achieved with a direct line-of-sight transmission, the company says.
'Maximum Efficiency'
Initially, Cisco was uncertain about whether to make VOFDM technology available at the very high frequency "millimeter" tiers such as LMDS, but the company has decided the market need in that category merits development of product, Smith says. "People are looking for maximum efficiency at all frequency tiers," he notes.
The first publicly announced user of Cisco's new system is MMDS operator Nucentrix Broadband Networks Inc. (www.nucentrix.com), the financially reorganized successor to Heartland Wireless Communications that controls licenses in 87 Midwestern and Texas markets. Nucentrix, now operating high-speed two-way data services commercially in Austin and Sherman, Texas, under development licenses issued by the FCC, is planning to switch to the Cisco platform as quickly as possible following the current round of testing, says Nucentrix CEO Carroll McHenry.
"Our plan is to be able to deploy on a wide scale by the fourth quarter, but that's highly dependent on the outcome of the trials and the timing of the FCC licensing process," McHenry says, noting that some 40 of 57 currently operating markets should be operational with two-way data services by the end of 2001. "In the short to medium term we're targeting the SOHO and small business markets, but we expect to expand into the residential market with these services, including voice, as equipment volume goes up and prices come down," he says.
The Cisco system offers a much more viable approach to offering interactive services over MMDS than current generation platforms, McHenry says. He cites the system's orthogonal modulation system and its ability to integrate multipath signals from reflective surfaces into a single non-line-of-sight source as key differentiators.
McHenry notes another key to the system's effectiveness is the fact that the VOFDM Broadcom chip exploits Broadcom's implementation of DOCSIS. Moreover, he says, the system can be implemented on DOCSIS-based circuit cards inserted into Cisco routers, allowing carriers to add wireless links in a wireline environment without changing out the edge switching system.
These efficiencies make it possible to offer a robust symmetric service at multiple data rates with coverage to non-line-of-sight locations from a single transmitter, McHenry notes. "Very likely we will sectorize our transmitters first and then move to multiple transmitter deployments as our customer base grows to accommodate demand," he adds. Cisco is making VOFDM technology available free of charge to Broadcom and other chip makers in an effort to establish it as a de facto industry standard that maximizes the broadband service potential of microwave-based delivery systems, Smith says. "Our game is to get fixed wireless moving as a viable competitor to cable and DSL," he notes. "We've chosen this technology as the one to back because it delivers both a higher spectral efficiency and a higher link efficiency than anything we've seen."
Broadcom is swinging behind VOFDM for the same reason, says Tim Lindenfelser, vice president of marketing for the chip manufacturer. "This technology overcomes the severe line-of-sight and other limitations of other approaches to MMDS," he says. The new Broadcom BCM2200 ASIC (application-specific integrated circuit), by combining the VOFDM technology with DOCSIS MAC in a single chip, will be priced low enough to allow manufacturers to deliver CPE at costs nearly on par with cable CPE, Lindenfelser says. "The main difference in cost is the antenna, although there's some tradeoff there with the cost of the tuner that's required in cable," he adds.
Along with providing strong coverage and high spectral efficiency within any given transmitter's reach, the technology also maximizes operators' ability to reuse spectrum through deployment of multiple transmitters with sectorized transmitter antennas, Smith notes. "It will be necessary to reduce the number of users accessing the spectrum from any area of coverage in order to ensure the necessary levels of bandwidth are available to support dedicated voice and data services," he says.
"It's not like MMDS has a lot of bandwidth to work with," Smith adds. "We think this technology is absolutely critical to efficient cellularization of the network."
Whether the new technique backed by Cisco will prove successful against the options that have led the market so far remains to be seen. But it's clear that, one way or another, carriers will soon find a means of making PMP services a reality in the United States on a much larger scale than they've been able to do so far. For competitors to assume otherwise based on the slow PMP rampup to date could be a prescription for unwelcome surprises in the year ahead.
A Platform for Going Operational
By Fred Dawson
Deployment of next-generation wireless broadband technology is already a reality when it comes to a handful of operating companies' use of the platform supplied by Adaptive Broadband Corp. (www.adaptivebroadband.com).
The Sunnyvale, Calif.-based vendor, formerly known as California Microwave, has been in the market with a time-division multiple access (TDMA)-based system for the past year and is the first to have spawned widescale deployments of this type of technology in the United States, thanks largely to the efforts of Fuzion Wireless Communications Inc. (www.gofuzion.com), a fixed wireless service provider based in Boca Raton, Fla. Now, along with Fuzion, which plans to be in 26 cities by year's end, a growing number of LECs and CLECs are looking at the technology, most commonly as a backup to DSL to ensure availability of high-speed Internet access on a marketwide basis.
All of this activity amid the slow rampup to use point-to-multipoint (PMP) technology at the MMDS and LMDS tiers rests on the fact that Adaptive chose to focus its first line of PMP products on the 200 MHz worth of unlicensed-national information infrastructure (U-NII) bandwidth at the 5.8 GHz tier. Fuzion seized the opportunity to use an advanced PMP technology without requiring FCC (ww.fcc.gov) licensing to launch services in southern Florida last year and now has operations under way in Tampa, Fla.; Rochester, N.Y.; Denver; and Toronto; with Washington, D.C. and Atlanta in queue as the next rollout locations, says Philippa Evert, vice president of corporate communications for Fuzion.
"The Adaptive technology has proven itself to be a robust competitive option that has been well received in the marketplace," Evert says. "Along with continuing to add cities in the U.S., we're also expanding in Canada and have announced plans to move into Latin America, starting with Panama City [Panama], where we've already launched service."
Fuzion, using an end-to-end ATM framework that taps into backbone support supplied by Qwest Communications International Inc. (www.qwest.com), offers Internet access to businesses of all sizes at speeds ranging from 500kbps to 45mbps and higher, Evert says. "The things people find most attractive about the service are the rapid time to connection and the scalability, which allows us to change a customer's bandwidth allocation from the radio transmitter with a simple keystroke at our network operations center," she adds.
Qwest's local services telephone unit inherited an ongoing test US WEST (now Qwest) began with the Adaptive system last year and, according to informed sources, remains interested in the possibility of using the technology as a backup to DSL. Now other carriers are preparing to make use of the platform in the U-NII band and in other bands, including LMDS and MMDS, as Adaptive brings new versions of the technology to market at year's end, says Todd Carothers, vice president of marketing at Adaptive.
"Carriers' interest in this technology goes beyond their needs for a DSL supplement," Carothers notes. "The big advantage lies in the higher speeds and the ability to serve customers' needs for more applications as their businesses grow."
The Adaptive system employs a proprietary packet-on-demand media access control (MAC) mechanism based on a 54-byte packet cell framework that assigns precisely the bandwidth needed by a particular end user only when that user is online and in accord with what the user is requiring moment to moment for communications in each direction. Facilitating this efficiency is the use of time-division duplexing (TDD), which employs time slots for sending messages in either direction over a given spectrum segment, thereby eliminating the need for separate upstream and downstream channels and a guard band in between.
"One access point can handle up to 254 simultaneous active subscriber units," Carothers notes, adding that this translates into 254 users per cell sector over a given radio frequency channel. With each base station serving up to six sectors and each 25mbps channel occupying 15 MHz of bandwidth, the system gives operators flexibility to make highly efficient use of any unused frequencies within the 5.8 GHz U-NII band, he adds.
