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Microwave Role Grows in Hot Intercity Market.

While microwave communications systems have been around for some 50 years--serving as the backbone of the nationwide telephone network for much of that time, and as the medium for satellite transmission and private networks from some 20 years--in many ways its capabilities are only beginning to be tapped.

Satellite systems are pushing into higher regions, with the Ku-band (14/12 GHz) and experiments looking at the still higher Ka-band of 30/20 GHz (see NASA story, page 88). Another offspring of telecommunications competition that's making heavy use of microwave is bypass.

The name of the game is intercity transmission, a market that's expected to reach about $65 billion by 1990, approximately double what it was in 1980.

Earlier this year, Chicago-based Arthur Anderson & Company released the results of an extensive study, "New Directions in Telecommunications." Among its many subject areas was the hot intercity market. According to its findings, bypass networks will grow significantly. The number of US organizations using private or shared bypass networks in 1980 was put at two percent, but it will grow to nearly 11 percent by 1990. Microwave, copper cable and fiber optics will constitute the largest portion of intercity communications capacity, with 29, 23 and 21 percent market shares, respectively, says the study.

Two of the engineer panels participating in the study, however, disagreed as to which medium will lead intercity capacity during the 1980s. The transmission engineer panel thinks it will be microwave transmission with 34 percent of capacity in 1990, followed by fiber optics with 25 percent and copper cable with 21 percent. The manufacturer engineer panel projects copper cable (25 percent) and microwave (24 percent) will lead, followed by fiber optics and satellites, both with 18 percent of capacity.

While on the subject of bypass, a recent study from International Resource Development of Norwalk, Connecticut sees bypass costing telephone companies perhaps five percent of their revenues. According to IRD, large corporations with communications expenditures exceeding $50 million annually are the most likely candidates to implement a bypass system. "Likewise, the interexchange carriers such as AT&T, MCI, GTE, SBS and others are also planning bypass technologies to avoid using the local exchange plant for access to their long-distance networks. But the most intriguing part of the bypass issue is that some of the divested BOCs are also considering or implementing bypass systems and are bypassing themselves." The Key to Bypass

According to the report, entitled "Telecom Bypass Markets," satellite communications, through the widespread deployment of domestic satellites and the development of satellite technology to increase the use of satellite capacity and develop new services, will be the key to bypass techniques used by large corporations and other telcos for bypass. Private business satellite networks provided by SBS, American Satellite, RCA and Western Union are enhancing their local distribution capabilities, and private satellite networks such as the OlympiaNet project open up the market for shared tenant services."

The study adds, "Private microwave represents the other steadfast threat to the local telephone company, having been used for some 20 years already. Private microwave in the relatively lightly used 18 and 23-GHz frequency ranges will be a most attractive alternate for companies seeking to lower communications costs, because the private microwave suppliers have the years of experience behind them that other bypass suppliers lack."

Some of the private microwave users have more than a little to think about, thanks to the direct-broadcast satellite service. Although most of the major proposed participants pulled out at the eleventh hour when it came time to ante up for their expensive plans, the die had already been cast with the allocation of spectrum for DBS.

This past August, the FCC affirmed its earlier decision to make available spectrum at 13 and 6 GHz to accommodate the 12-GHz licensees being displaced by DBS. In the same action, the commission clarified actions with respect to the 18-GHz channeling plan. In an order released in September 1983, the FCC established an allocation in a segment of the 18-GHz band (18.36 to 19.04 GHz) for use by private and common carrier Digital Termination Systems (DTS) and by private, common carrier and broadcast auxiliary point-to-point operations. It also allocated 10.55 to 10.68 GHz, previously allocated exclusively for common carrier DTS, for use by private DTS and by the private operational-fixed service for point-to-point operations.

A commission order provided spectrum in the 12.7 to 13.15-GHz and 6.525 to 6.875-GHz bands for the existing 12-GHz (12.2 to 12.7-GHz) private fixed service users who must vacate for DBS. It also completed the allocation of the remaining segments of the 18-GHz band (17.7 to 19.7 GHz) for private, common carrier, broadcast auxiliary and cable operations.

Reconsideration petitions for the two proceedings were seen as interrelated, so the FCC addressed all in a single order this past August--DTS, 18-GHz band allocation, 18-GHz technical standards and 12-GHz reaccommodation procedure.

The FCC affirmed its previous action to allow private DTS operations on the four 10.6-GHz channels previously allocated to common carrier systems. The channeling plan for the 18-GHz band is to be used to support terrestrial fixed point-to-point and point-to-multipoint operations; the band is also co-equally shared with the fixed-satellite service. The FCC modified the channeling to support contiguous spectrum for cable television operation and to have a uniform transmit/receive separation for the narrowband channels. However, a requested 120-MHz transmit/receive separation is not provided for in the revised channeling plan. The currest waiver to market equipment not complying with the channeling plan is extended for two years from the release of the order.

Concerning the technical standards adopted for the 18-GHz band, the commission postponed the implementation of the 1.0 b/s per Hertz spectrum efficiency standard until December 1, 1988, so manufacturers will not be required to redesign existing equipment in order to meet the 0.6-b/s per Hertz interim efficiency standard.

Those 12-GHz band users being displaced by DBS have a variety of choices, but there is no "best choice" that applies in every case, according to Comsearch, a Reston, Virginia-based firm that provides path design, frequency coordination, system integration and other engineering services. It points out that these users have until September 1988 to relocate their service to the 6, 13 or 18-GHz bands. "In effect, the FCC gives 12-GHz users a choice of fitting themselves into relatively crowded bands (6 and 13 GHz) or moving to a new band with significantly different transmission characteristics (18 GHz)." Good News/Bad News

According to Comsearch, the 13-GHz band (12.7 to 13.25 GHz) appears to offer a "no-problem" alternative from a technical standpoint. "In fact, some existing 12-GHz radio equipment can be made to work in 13-GHz frequencies with minor modifications. Some waveguides and antennas may work with no modification at all. The bad news is that there are already over 83,000 links licensed on the 13-GHz band for the Cable Antenna Relay Service (CARS)."

Looking at the 6-GHz band, Comsearch says it's less-desirable than 13 GHz because it requires new investment in transmission equipment, and because 10-MHz bandwidths are the maximum allowed without a waiver. In addition, the narrow bandwidth limits 6 GHz to non-video applications. It says that a major potential problem with 6 GHz is its larger path clearance needs, which may demand complete re-engineering of the path.

As for 18 GHz, Comsearch says that if rapid or substantial growth is expected for the system, the 18-GHz band (17.7 to 19.7 GHz) may be the best choice for a move. "In some cases, it may be the only choice, if suitable 13-GHz or 6-GHz channels are not found. The drawbacks of 18 GHz seem substantial: shorter transmission paths, higher construction costs and less-developed technology. The advantages are an essentially open band (under 200 licensees) and the opportunity to use any of several bandwidths (up to 80 MHz)."

Well, no one ever said it would be easy. As in virtually all other areas of telecommunications today, you make the best choices with the best information available--then take your chances.

Comsearch points out that timing is all-important, noting that "The FCC has given no special priority to displaced 12-GHz users moving to 13 GHz or 6 GHz. After September 1988, all rights to move these bands expire. As a result, it is important to begin evaluating the alternatives as soon as possible."

One of the bright spots is that there is an abundance of microwave equipment and services available today. Following the feature articles in this section describing some current uses of microwave technology is a roundup of presently available vendor offerings.
COPYRIGHT 1984 Nelson Publishing
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Copyright 1984 Gale, Cengage Learning. All rights reserved.

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Publication:Communications News
Date:Oct 1, 1984
Previous Article:New Data Switch the Hub of OCAM's Network.
Next Article:Computer Giants Giving a Major Boost to Increased Use of Corporate Videotex.

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