Delivery Of Broadband Services Research Articles

Accurate performance modeling of subcarrier multiplexed fiber/radio systems: implications of laser nonlinear distortion and wide dynamic range

In this paper, we present an analytical approach to accurately assessing the performance of subcarrier multiplexed optical systems for the delivery of future mobile radio broadband services. The existence of a wide dynamic range of power levels in the return link, together with laser nonlinear distortion, represents a major problem and makes performance evaluation difficult. By modeling laser nonlinear distortion using Volterra series analysis, we show that the performance assessment of these systems becomes not only tractable, but also that they can be can be optimized based on the worst case condition. This analysis is performed here for the case of continuous phase frequency shift keying (CPFSK) modulation, for which we calculate the power spectral density (PSD) of the intermodulation products. The overall system performance is that investigated, and its dependence on laser bias and RIN is examined. As an illustrative example we consider a specific 50 channel CPFSK system occupying the bandwidth of 2 to 2.1 GHz.

Hybrid fiber/coax in the public telecommunications infrastructure

The benefits of the hybrid fiber/coax (HFC) architecture for the delivery of interactive broadband services have been widely discussed in the past few years. The cable television industry began deployment of this infrastructure in 1989 to support the broadcast video business. Recently, domestic telephone companies have looked at various degrees of HFC implementation, ranging from the delivery of broadcast video only to full telephony integration. The article looks at the HFC network evolution from a broadcast, non-essential, isolated architecture to a robust, interactive, broadband element within the public telecommunications fabric. Regional networks, interface to the public network and network management systems are a few of the significant issues with respect to the viability of HFC as the access layer to the information superhighway. If the HFC platform proves viable, telephone companies will adapt it to meet their needs in a fully integrated system. >

Architecture for delivery of broadband services to the residence

AbstractThis paper presents a technology and architecture perspective on the cost of evolving today's copper access network, optimized for POTS, to a fibre access network providing both narrowband and broadband services. Architectures are assessed using application studies based on cost models for actual routes in North America. This study identifies three architectures as serious candidates (i.e. close to copper in cost) for providing POTS service in 1992: the double star, the active pedestal and the star‐bus.The active pedestal and the star‐bus architectures were similar in first costs and were the least expensive, costing between 5 and 15 per cent more than the copper reference depending on the number of subscribers subtending a given optical fibre. The double star is 20 per cent more expensive than the copper reference.All three architectures are potentially attractive for broadband service upgrade depending on the bandwidth required per subscriber. The star‐bus is most bandwidth sensitive. Moderate video bandwidths, nominally 150 Mb/s/subscriber, favour the active pedestal architecture. Conversely, service environments requiring much greater than 150 Mb/s/subscriber favour the double star architecture.