07-Jul-2014
Read the WiMAX Forum's latest white paper below!
Introduction
Wireless technology offers the best alternative for the deployment of a Smart Grid (SG) network. It is the most cost-effective, quick to deploy, and it is compatible with existing utility infrastructure and right-of-ways. Although wireless has the potential to meet all of the requirements for a secure Smart Grid network, the lack of suitable spectrum specifically allocated for utilities has been, and continues to be, an obstacle for SG deployments. Obviously utilities have the ability to use unlicensed spectrum in a variety of bands and they have access to existing public networks. Although these options can indeed play a role in some SG network segments or selected geographic regions they are not suitable for a complete end-to-end network solution. Unlicensed spectrum is prone to congestion and interference and capacity may not be available when crucially needed by utilities. With the infiltration of smart phones and growing demand for new wireless applications, public networks are barely able to keep up with the current demand from existing customers and therefore, unlikely to have excess capacity to offer utilities for SG. In times when utilities especially need adequate data communications, whether for disaster recovery or periods of peak electric demand, public networks or unlicensed spectrum are options that cannot be guaranteed to be available. The potential benefits of a US nationwide Smart Grid network are significant but, unfortunately, without utility access to suitable spectrum, these benefits may never be fully realized.
Other papers and presentations in the past few years have also addressed SG spectrum issues. Armes, provided an analysis for the 1800-1830 MHz band in a 2010 paper describing its use in point-to-point SG backhaul applications [Ref 1]. Later that year Armes and Bender, did a SG applicability analysis for a UTC paper that included the 700 MHz and 14.5 GHz bands along with the 1800 MHz band [Ref 2]. In 2011, Rodine and Drucker in an EPRI presentation, made some compelling arguments for the need for dedicated SG spectrum and provided a throughput analysis for a point-to-multipoint field area network (FAN) comparing deployments at 700 MHz and 1800 MHz [Ref 3].
The goal of this paper is to provide a quantitative basis for the amount of spectrum required and to show the trade-offs between different frequencies that may be considered for a SG network taking into account the detailed work that has been done since the above-mentioned papers with respect to path loss models, SG capacity, and SG latency requirements. Three frequencies are used for the analysis; 700 MHz, 2000 MHz, and 3700 MHz. The number of base stations (BS) that must be deployed to meet the SG coverage and throughput requirements is closely related to the network complexity and cost and will, therefore, be used as the key metric for evaluating the trade-offs between the frequency bands. The complete SG network comprises a number of sub- networks or segments [Ref 4]. For the purposes of this analysis, the networks considered will be a Field Area Network (FAN) and a Wide Area Network (WAN).
