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Article Excerpt
To deploy broadband networks, service providers, such as competing local exchange carriers, need robust plans for providing various types, amounts, and locations of services at competitive prices. Broadband networks generally consist of an access component (wireless access), a concentration component (a wireless aggregation point or hub), a service routing or distribution component (a central office or metro switch), and various combined or separate distribution components (a long-haul backbone data or voice network). Because access, aggregation, and routing or distribution vary greatly in requirements, we developed a method and platform for planning the components of fixed-wireless-broadband (FWB) systems for local loop access. We have helped various service providers to analyze and design many networking scenarios using our methods. The service providers have used these scenarios and their predicted financial outcomes to plan FWB access networks tailored to meet their marketing and financial goals. By implementing our method, one service provider has improved its planning process, achieved a competitive advantage in its markets, and increased its annual service revenues by tens of millions of dollars.
Key words: technology: network, models; facilities, equipment planning.
History: This paper was refereed.
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In the United States, American Telephone and Telegraph, Inc. (now AT&T) historically and almost exclusively provided telephone service. Following the deregulation of the industry in 1984, the Federal Communications Commission (FCC) limited AT&T to providing long-distance telephone service, and the regional Bell operating companies, such as Bell Atlantic and Southern New England Telephone, thereafter provided local telephone service. Thus, following deregulation, the regional Bell operating companies initially were the exclusive local exchange carriers and maintained the subscriber loops between the public switched telephone network and the individual telephone subscribers. However, as competition increased, other companies entered the business of providing telephone services.
The growing demand for high-speed data transmission increased the demand for access in the local loop and further increased the number of service providers. To permit competition in the local telephone market, the FCC required the regional Bell operating companies to unbundle their subscriber loops so that competing local exchange carriers and other service providers could access subscribers. Typically the unbundling occurred along the subscriber loop between the local exchange carrier's central office and the subscriber's equipment with costly hard-wired connections. With the increasing popularity of wireless networks, however, service providers gained access to customers without wired connections to their local loops (Bates 2001, Calhoun 1992, Vacca 2001, Webb 2000).
Service providers pursued several access technologies, including enhanced copper digital subscriber lines (xDSLs), cable networks, 3G mobile wireless platforms, fiber optics, satellite broadband networks, and fixed-wireless-broadband (FWB) systems (Gillespie 1997, Webb 2000). New market entrants often adopted FWB systems, which they could deploy quickly and inexpensively. Although we focus on fixed wireless in this paper, the methodology or algorithms and the framework of the underlying tools developed are generally applicable for planning other broadband access networks, such as xDSL, cable, fiber-to-the-home, WiFi, and WiMax. (In fact, Bell Labs used the methodology and the framework of the tools we developed for planning xDSL-based network solutions.)
These emerging access technologies offered market and network planners advantages for building local access networks as well as challenges. For example, service providers are often uncertain about the types of services required, their bandwidth, and customers' locations. Before signing up customers, they must typically prioritize planned activities and invest in real estate and spectrum needs of the network.
Thus, before entering a market, a service provider must analyze the market to evaluate the costs and benefits of entering it. Service providers targeting commercial customers obtain information about the tenants of commercial buildings and their telecommunication needs and use existing forecasting models that correlate, for example, industry codes, number of employees, and annual revenues to forecast potential customers' telecommunication needs.
In addition, the network planners estimate the costs of engineering the network infrastructure the customers will need, minimizing the business risk while satisfying estimated bandwidth requirements. Because costs decrease per node as the number and location of nodes in a broadband network increase, the planners must quantify the costs of all possible network configurations. In this manner, the service provider can make an informed decision about whether to proceed in a given market and can prioritize markets, market strategies, and customer segments.
Service providers consider uncertainty in various types of services (for example, voice, data, frame relay, and PBX (private branch exchange)), their bandwidth over time, and the business locations that may require services. Before service providers seek their first customers they must
(1) Determine the areas (markets or cities) to pursue,
(2) Locate appropriate real estate for their network elements,
(3) Estimate the equipment and associated capital needed, and
(4) Decide how much wireless spectrum to bid on.
The broadband network planning methodology and tool platform we describe in this paper is used for the following purposes:
(1) Analyzing the effects of variations in service demand on equipment configurations and network topology,
(2) Determining the costs and benefits of each such configuration, and
(3) Providing necessary information for implementing a desired configuration.
We developed a planning methodology based on our knowledge of network planning, design, and business modeling. When provided with relevant demand models and data, information on network architecture and services, the planning methodology and platform sizes networks in terms of bandwidth and equipment requirements and provides the business cases for different scenarios. (Each scenario represents a demand data set based on such parameters as the number and type of buildings, and their demand-growth rates that results in a certain network configuration after applying the planning methodology.) Using the methodology, the planners can easily
--Develop network designs, and
--Engineer network elements.
General Inputs
To study what-if scenarios, analysts can enter various parameters in the planning platform:
--Expected penetration of the market, demand-growth rates, and service bandwidth requirements,
--The types of services to provide and their prices,
--A schedule for providing network nodes and their locations,
--Financial parameters, and
--Expense factors for facilities, provisioning, maintenance, and customer care.
General Outputs
For each scenario, the planning platform provides
--The quantities of network elements required and the bandwidth they use,
--The annual expenses associated with that scenario for customer care, provisioning, maintenance, sales, leased facilities, and so forth,
--The business case, including cumulative discounted cash flow (CDCF), net present value (NPV), earnings before interest, taxes, depreciation and amortization (EBITDA), annual income, and the year-end balance sheet.
For as many as 24 scenarios, it will also compare their economic measures.
The existing network-planning tools in the market fall into three broad categories (Pinzon 1998, Newton 2000): For planning access networks, the tools available include Lucent's access tool and CAPNET, and the commercial tools: (1) WINMIND, (2) AUTONET, (3) Netmaker XA, (4) NPAT, and (5) Composis. For planning wireless networks, the tools available include Lucent's INDT-WIND, PLANET, and WISE. For planning data networks (ATM/IP), the tools include Lucent's INDT-ATM, SimNet, and NPAT and the commercial tools (1) CANE (simulation only), (2) Winmind, (3) Netmaker XA, (4) Netscene-ATM, (5) NPAT (also used at Lucent), (6) WorkBench (an ATM planning tool), (7) Comnet (simulation only), (8) OPNET (simulation only), and (9) NetQUAD.
None of these tools described in the literature take an integrated approach to solving the complete network-planning problem that service providers face. Some locate the service nodes, which for our method must be specified. Our method locates the hubs, engineers them, and develops a business case with various financial metrics based on analyzing the network, which none of the existing tools do....
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