LMDS is a broadband fixed wireless system that operates at 28 GHz and occupies 1300 MHz of licensed spectrum. LMDS offers line-of-sight coverage over a 3- to 5-km range and holds within its reach the capacity to provide data and telephony service for up to 100,000 customers. A 360-degree transmission pattern, sectorized into four quadrants of alternating polarity, allows effective reuse of all spectrum resources and an overlapping node pattern that drastically improves coverage for a targeted customer base⁴¹.

Figure 21 Click here to enlarge

LMDS is initially best for areas of concentrated traffic. It also supports low traffic scenarios as the network is deployed. Physically, a system consists of two primary functional layers: transport and services. The transport layer comprises the customer premises rooftop unit (RTU) and the node electronics. The RTU solid-state transceiver is approximately 12 in in diameter. The node includes solid-state transmitters, receivers, and other related elements located at the transmit site. The services layer comprises a network interface unit (NIU) at the customer premises and the base electronics. The NIU provides industry standard interfaces to the customer, and the base provides control and transport functions from the hub site or central office/traffic aggregation site.

LMDS reliability compares favorably with fiber. In high-rain areas, adaptive power control holds desired link margins. Occasionally, cell size adjustments are required, but in areas with high rainfall such as Brazil and Mexico, economic 4 to 9 s of availability has proven achievable.

For service providers pursuing a competitive local exchange carriers (CLEC) business model, the technology is extremely cost-effective to implement. LMDS can be deployed in a matter of days and integrated with an existing network.

Incremental installation significantly improves the business case, allowing for additional implementation only as the customer base develops. As conditions change, LMDS is readily redeployable. So which end users should see the benefit of this technology first?

LMDS Product Opportunities

In the communications world today, significant opportunities are available in local access. Though the opportunities have been open to entrepreneurs since divestiture, the LECs have had a defacto monopoly. The multibillion dollar question has been how a CLEC can compete with thousands of miles of installed and paid-for copper. LMDS provides an extremely workable technology, which when planted in the fertile fields of explosive bandwidth requirements responds profitably.

Still, LMDS is no panacea and will see its widest deployment initially in the higher-traffic markets of businesses and multidwelling units (MDUs). The market segments and transmission speeds illustrated present the best opportunities for LMDS implementation.

Opportunity zones are not mutually exclusive but likely will be implemented differently because of the technical and economic issues associated with providing the most robust service. Each can, should, and will be deployed over time, and the proper technical architecture will provide a platform to support each of these service layers within a common point-to-multipoint rf system fabric.

Large and medium-sized businesses depicted in the red zone call for supporting trunked telephony, private data circuits, remote access, and local-area network (LAN) interworking⁴². These are existing, high-traffic, and increasingly bandwidth-consumptive applications. Some are served by internal networks or incumbents, which can be challenged by lower-cost solutions. As bandwidth needs continue to expand, greater resources will be required. These subscribers, given their relatively small numbers but demanding purchasing criteria, are best served with dedicated point-to-point links operating in the LMDS band. The service provider also will use these links for internode distribution.

Figure 22 Click here to enlarge

Medium-sized to small businesses and MDU-based residential tenants reflect the sweet spot for initial point-to-multipoint deployment. For medium-sized businesses, the economic threshold for private network implementation is harder to cross than for large businesses. Many of these entities clamor for advanced services but lack the internal staff and/or finances to specify and procure their solutions. Significant opportunities exist to offer previously unavailable high-capacity services to this segment or to replace higher-cost private solutions with lower-cost and more flexible shared services.

Residential bandwidth requirements constantly increase, but because of installed network insufficiency, MDUs presently emerge as an underserved segment, which holds great promise. The drift toward convergence (the ability of one network to serve all applications) is becoming a strong current with fax, entertainment video, videoconferencing, voice, and data transmission through the ubiquitous PC. LMDS is extremely effective in concentrated user locations that demand multiple integrated service offerings.

Small businesses have needs similar to their larger brethren but lack the economic clout to implement private networks that satisfy those needs. This is one of the most underserved market segments today. The capabilities of LMDS easily can serve this market, especially if the end users are geographically concentrated. This product opportunity zone will be best served with an architecture that blends the advantages of point-to-point's dedicated nature with the shared aspects of point-to-multipoint. A shared broadband downstream channel matched with frequency division multiple access (FDMA) uplinks is the most effective solution for this initial LMDS subscriber base.

The third subscriber zone (see Figure 22 above) presents a potentially huge customer base but brings with it some cautions for early deployment. Small office, home office, and work-at-home telecommuters are an increasingly growing segment of the business population. This segment poses concerns for service providers looking for high traffic and the resulting high revenues on which to base a new business venture.

The sporadic traffic patterns created by these entities beg for the deployment of a broadly shared access medium. In addition, these customers are often located in leased-site business parks or in single-family dwellings. As a result, the line-of-sight restriction for LMDS has its largest impact. Time division multiple access (TDMA) systems represent the most attractive means of achieving the economics necessary to address these subscribers. Still, the prudent service provider will use the TDMA systems to expand its initial network coverage based on the revenues reaped from a smaller but higher value core subscriber base.

LMDS service providers have a number of targeting options. In addition to the end-user market segments, tremendous opportunities for wholesale-type traffic arrangements exist, such as providing PCS or cellular backhaul for other wireless carriers looking to escape the grip of the incumbents for T1 links. This application puzzle is summarized below in Figure 23.

Figure 23 Click here to enlarge

The best LMDS vendor partners will assist the service provider in prioritizing and providing the best technical solution for each application.

A Broad Business Perspective

New local access service providers will have numerous challenges to overcome because no tried-and-true templates exist for this business. Those entering are truly on the leading edge of a new paradigm in communications. But therein also lies great opportunity.

LMDS deployments will require wide skill sets brought together in innovative ways and through creative partnerships. Figure 24 below gives a graphic representation of what an LMDS business might look like.⁴⁴

Figure 24 Click here to enlarge

The service provider is the ultimate visible entity, providing operations and marketing and creating alliances with various partners (CLECs, IXCs, etc.). The structure on which the service provider sits will largely determine the possibilities of the business. If a choice is made to select a vertically integrated solution, certain limitations as to interfaces and platforms may dictate the eventual shape and customer set viable for the business.

Alternatively, if the choice is made to compile all the pieces from disparate vendors, the service provider risks venturing into uncharted territory unguided by know-how in the business. The preferred solution is a vendor team that provides the knowledge, experience, requisite technical solutions, and flexibility to support third-party choices made by the service provider. Look for vendors who have partnered with the best to address their noncore elements and have made the choices that grant the greatest customer effectiveness and flexibility.

To ensure that every aspect of deployment is accounted for, look for an LMDS provider who offers the comprehensive network integration service⁴⁵ (see Figure 25 below). Each element of network integrations should be present to facilitate the seamless deployment of a successful enterprise.

Figure 25 Click here to enlarge

Network engineering incorporates traffic and capacity engineering, selection of network elements based on service requirements, projected take rates, signaling system 7 (SS7) interconnection design, transport network design, and network operations planning. Interconnection agreements consist of coordinating interconnection to LECs; interexchange carriers (IXCs), and Internet service providers (ISPs) and facilitating the agreement process.

Central office site selection involves choosing the optimized location with regard to the proximity to interconnect points to LEC/IXC/ISP networks, building availability, price, and best value. Network integration and acceptance testing include management of issues related to data switching equipment, telephony switching equipment, video headend equipment, network operations software, multiplexing equipment, SONET and microwave transport equipment, and fiberoptics.

Training involves personnel concerned with installation, integration, maintenance and repair, and network management. Project management includes oversight of the turnkey project, contractor and vendor selection and management, master schedule and budget creation, adherence, quality control, and progress monitoring and reporting.

The LMDS access integration mosaic significantly eases the installation burden from the service provider and puts it squarely on the shoulders of the equipment supplier. Look for an rf system integrator vendor who provides all elements.

Again, project management entails developing the overall project plan and implementation schedule, coordinating with all suppliers for delivery of products and services, progress reporting, and adherence to budget, schedule, and quality specifications. Rf engineering includes site selection and design, propagation analysis, interference coordination, capacity planning, and loss-of-signal analysis.

Site acquisition is comprised of zoning analysis, property ownership due diligence, lease negotiations, municipal planning approvals, and assessment of existing rights of way. Construction consists of tower, structural and building code analysis, engineering design, tower and building site design, zoning and building permit approvals, and construction management.

Installation and integration relate to node and base station equipment, power systems, acceptance testing and commissioning, and interconnection to the network. Training involves classes for hub operations and maintenance, customer premises equipment installation, maintenance and operations, element management, operations, and administration.

The preceding discussions have presented an educated perspective on what LMDS is, where and when it makes sense to deploy, and what challenges lie ahead for new service providers.

A Strategic Model for Partnership

Finally, system vendors typically partner with the most effective equipment, knowledge, and support suppliers in the marketplace and provide an integrated face to their customers. Today, no one entity in the LMDS market can say that it excels in every component and every area of customer service. Therefore, it is necessary for a partnership to comprise sectors of core competency covering the entire picture.

Creative partnering, an integral piece of the groundbreaking, is key to providing the service provider and end user with optimal choices. The philosophy is simple in its presentation but certainly more complicated to implement. Suffice it to say that the unknown in this graphic is the triangle rising up the center area of the architecture most affected by the LMDS system integrator. Service providers should not lightly place their bets in the triangular region but rather must perform the requisite due diligence on those entities claiming to fill this area of responsibility.

The rf system integrator's relationships with the vendors who occupy the flanking areas on this strategic architecture are critical as well. Open interfaces afford the service provider greater options, but selected vendor integration options may provide significant performance, management, and cost advantages while not limiting total network architecture flexibility.

41, 42, 44 45 -    Tom McCabe, "What Lies Ahead for LMDS," America's Network, Advanstar Communications, 201 Sandpointe Ave., Suite 600, Santa Ana, CA 92707, 2000.