The Land Mobile Communications Council’s proposed 800 megahertz interstitial channel interference contours has generally attracted support from several parties, including two major public safety organizations. The LMCC submitted its proposal in its reply comments in WP docket 15-32 in the FCC’s 800 MHz band interstitial channel proceeding. ”
The matrix developed by the LMCC incorporates protection contour values to be applied to and from all known technologies operating in the 800 MHz band,” said the National Public Safety Telecommunications Council, whose board includes representation of several groups that are also members of the LMCC. “NPSTC believes the LMCC recommendations will serve public safety and the overall land mobile community well to protect systems on existing channels and allow implementation of new interstitial channels that provide more spectrum opportunities. For this increase in existing spectrum use to be effective, interference must be minimized for both incumbents on the current main channels and for applicants on the proposed interstitial channels. The LMCC recommendations are consistent with that requirement.”
The filing continued, “The LMCC recommendations show significant thought was given to the protection criteria. It appears the multiple technologies deployed in the land mobile bands were fully considered and included in the recommended matrix of protection values. While this approach is more complex than that traditionally used in frequency coordination, NPSTC believes that such an approach is necessary. Also, if an application for a proposed interstitial operation fails the contour approach set forth in the LMCC matrix, frequency coordinators should have the option, with the applicant’s consent, to use a more comprehensive engineering study.”
The Association of Public-Safety Communications Officials-International, which is an LMCC member that is represented on NPSTC’s board, said, “Prior to the development of the LMCC proposed contours, APCO commented that ‘[c]ontours used in the coordination process must be subject to independent testing and verification (e.g., by TIA).’ While APCO appreciates the efforts of LMCC and believes that the proposed contours can be workable, they are untested. Thus, we would encourage manufacturers to submit test reports into the record to verify that no interference would result from new interstitial operations.
Further, as APCO has said in its previous comments, and as noted by the Public Safety Communications Council (of which APCO is a member), APCO would support use of tile-based matrix studies using TSB-88 methods when the proposed operations of a public safety applicant fail a contour analysis.”
Mobile Relay Associates said it “supports the major portion of the LMCC proposal, and applauds LMCC for its diligent efforts in this arena. However, one portion of the LMCC proposal is inconsistent with both the rest of the LMCC proposal, and with over thirty years of public policy. That one portion of the LMCC proposal is its proposed treatment of instances where there is absolutely no spectral overlap between the incumbent station and the proposed station. Neither the Commission nor the LMCC has ever required an interference analysis when there is a complete absence of spectral overlap, and, as to very narrowband 4 kHz emissions in particular, there is a plethora of real-world experience proving that interference to incumbent stations does not exist in the absence of spectral overlap.”
“With regard to the licensing of new very narrowband 4 kHz operations on offset channel centerpoints in the 800 MHz band, the LMCC proposal fails to strike the appropriate balance between protection of incumbent operations and enabling efficient re-use of spectrum,” MRA added. MRA also said that “implementation of a regime to license interstitial channels at 800 MHz will present a challenge to the Commission’s enforcement personnel, since they would have to inspect stations with respect to their emission types. Such inspections will require more personnel, and appropriate testing and monitoring equipment. The Commission should stop treating its District Offices as unwanted step-children, and begin providing those District Offices with adequate tools to enforce Commission rules (including any rule adopted herein) and maintain a level playing field among competitors.”- Paul Kirby
Courtesy TR Daily