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HomeMy WebLinkAboutBill Johnson Report-VZW-111Wiedmaier tower-1William P. Johnson RF Engineering Consultant PO Box 20263 Rochester, NY 14602 October 21, 2024 Town of Ithaca Planning Board Attn: Ms. Christine Balestra, Senior Planner Town of Ithaca 215 N. Tioga Street Ithaca, NY 14850 RE: Proposed Wireless Telecommunications Services Facility - RF Site Review for Verizon Wireless / “Sunny View” Site 111 Wiedmaier Court (Tax Parcel No. 56-4-1.22) Proposed 134’ New Monopole Tower plus 4’ Lightning Rod (138’ overall) Dear Ms. Balestra, Per your email of October 3, 2024, this revised preliminary report will address only the RF engineering issues specified in Town Code §270-219 R (2) that the planning board must consider whether there is a showing of current “need” and an existing “significant gap” in wireless telephone service. We were directed during the planning board’s October 2, 2024, meeting to revise our preliminary report and follow only Town Code requirements for purposes of RF engineering analysis. NEED Town Code §270-219 R (1) (c) [2] contains specific RF engineering requirements necessary for special permit approvals and defines the limitations for evaluation of those requirements. Need. The applicant has proven a compelling need to address any significant gaps in the applicant's personal wireless services (the ability of wireless telephones to make and receive voice calls to and from landlines that are connected to the national telephone network) through the proposed facilities and not through any other solution, and the facility presents a minimal intrusion on the community. Verizon Wireless (“Applicant”) uses LTE (acronym for “Long Term Evolution”) technology that dynamically allocates available bandwidth for user transmissions using “resource Town of Ithaca Planning Board, October 21, 2024 Page 2 of 5 elements.” Resource elements are small bandwidth channels contained within their licensed spectrum bands that can be dynamically aggregated based on the momentary throughput demands of users. Generally, aggregation of more resource elements corresponds to higher information rate transfers measured in “Bits per Second” (BPS). Traditionally there was a distinction of how analog voice calls and digital signaling data exchanges were transmitted to and from Personal Wireless Services Facilities (PWSFs). Using LTE technology, whether the exchange of information relates to voice information that has been digitally transformed or digital data, the entire transmission is sent and received using digital information signaling formed in packets. Packets are collections of digital information “bits” that are framed with headers, cyclic redundancy code information for forward error correction, and other information to facilitate reliable decoding within limits of system capability and subsequent reconstruction of the information in a useable form. If the encoded information arrives at a receiver (i.e. the mobile device or the PSWF) with less than sufficient signal strength to allow reliable decoding, the transmitted information will contain “bit errors” due to system noise levels that are inherent in any electronic communication system. Bit errors ultimately prevent proper reconstruction of the original information. When this happens, the communication link breaks down (e.g. a “dropped” call) and may be disconnected by the LTE controllers. Applicant proposes deployment of several frequency bands of operation. The frequency bands discussed in the permit application materials are “low-band” (700/850 MHz) and “mid-band” (1900/2100 MHz). We suspect Applicant will also deploy additional mid-band spectrum in the 3700-3980 MHz range (the partially re-purposed satellite downlink C-band) that is used by Applicant for fixed-wireless broadband service. Neighbor site “Brookdale” gamma sector provides existing low-band RF coverage and capacity to the target improvement area as shown in Applicant’s Exhibit H page 15 and 17. The “Brookdale” site is too far away to provide any usable mid-band RF coverage or capacity. In accordance with Town Code, Applicant must show not just “need” but a “compelling need” that is affected by not just “gaps” but “significant gaps” in their service area. Town Code defines the meaning and limitations of these terms. Town Code requires the analysis relate only to “the ability of wireless telephones to make and receive voice calls to and from landlines that are connected to the national telephone network.” Town Code is silent on the evaluation threshold of acceptable levels of access failure due to low signal level or capacity- related issues, only that there is the ability to make and receive voice calls. Town Code §279- 219 R (2) (a) states that “an applicant's claim of need for future capacity does not constitute evidence of a significant gap.” Town Code does not specifically envision use of digital LTE metrics for real-time evaluation of reliable communication or user capacity limitations but instead relies upon “In-kind call Testing” as defined in Town Code §279-219 B. The LTE capacity metrics such as those presented in Exhibit H are plotted for the worst-case capacity demand levels each day. When the board considers the existence of a “significant gap,” Town Code §279-219 R (2) (a) requires evaluation of “whether the applicant's customers are Town of Ithaca Planning Board, October 21, 2024 Page 3 of 5 affected for only a limited period of time.” Applicant provided Exhibit Z materials to meet the requirements of Town Code definitions of compelling need and significant gap. We will address these in order: Compelling Need - Town Code §279-219 R (1) (c) [2] In addition to the existing low-band RF coverage shown in Exhibit H pages 15 and 17, Exhibit Z slides 10 and 11 shows “dropped connections” and “access failure” locations for all frequency bands discussed in the exhibit. Low-band signals propagate with less loss than mid-band signals but low-band spectrum represents only about 10% of Applicant’s bandwidth. These data are collected by the LTE controller using GPS data reported from the user’s mobile device. We note that the maps are titled “Dropped Connections” and “Access Failures” which, from an LTE perspective, may not be only voice call dropped connections or access attempts. However, the fact that LTE sessions were dropped or could not be initiated implies generally that voice calls in progress could also be dropped or attempts to dial out may not be successful. Based on the map locations markers, the dropped connections and access failures were in a mix of outdoor, in-vehicle and in-building locations along and between area roads and demonstrates the potential inability to place and receive phone calls for convenience and emergencies. The wireless communication environment is such that when unavoidable “fading” occurs, connections may be dropped, but it does not mean that every existing connection or access attempt will fail as long as conditions provide at least minimal signal strength and user capacity at the PWSF serving the area. The issue in either case is predictable reliability. The data shows that reliability is poor in the test area. We therefore conclude that Applicant has shown a “compelling need” since wireless reliability in the targeted improvement area is poor. Significant Gaps - Town Code §279-219 R (1) (c) [2] Application materials Exhibit H slides 15 and 17 show existing low-band RF coverage. Slides 19 and 21 show existing mid-band RF coverage. Using the Town Code, §279-219 R (1) (c) [2] [a] requirements, identification of a “significant gap cannot be established simply because the applicant's personal wireless services operate on a frequency which is not the frequency most desired by the applicant. An applicant's claim of need for future capacity does not constitute evidence of a significant gap.” Since Applicant shows RF coverage for low-band in Exhibit H slides 15 and 17 above -105 dBm, a minimal level for outdoor service, and some areas where RF coverage is above -95 dBm, Town Code arguably precludes a finding of a “significant gap” even though there is no mid-band service in most of the targeted improvement area. Based on the information in Exhibit H for low-band, we would anticipate that low-band mobile device connections inside vehicles and inside buildings may be unreliable for in-vehicle and in-building users since penetration of vehicles and structures reduces signal strength. Applicant’s Exhibit Z page 9 states that the Dropped Call Rate Town of Ithaca Planning Board, October 21, 2024 Page 4 of 5 (DCR) for the proposed service area is 11.84% compared to their standard DCR of 1%. The stated DCR is for both low-band and mid-band operation. If a call is in progress in mid-band frequencies when a user transits into an area the mid-band call will drop. If a user is already in an area that lacks mid-band service and there are either low-band capacity limitations or insufficient low-band signal strength (e.g. in-vehicle or in-building locations) it is likely that access will be denied or, if initiated, the connection may drop. We note here that considering the lack of RF coverage shown for mid-band in Exhibit H pages 19 and 21, the capacity issues presented in Exhibit H for neighbor site “Brookdale” gamma sector, and the in-vehicle drive test results for low-band in Exhibit Z a different finding may be possible in accordance with Town Code §279-219 R (2). With respect to Town Code and the stated limitations on analysis there is arguably no finding of “significant gaps” based only on the RF propagation plots for existing low-band RF coverage. We recognize that low-band may not be Applicant’s preferred frequency of operation since mid- band frequencies provide approximately 90% of Applicant’s licensed operational bandwidth and it heavily used for mobile device data services such as Internet access, mobile navigation applications such as Waze and Google Maps, and text access to the E911 system. Minimal Intrusion on the Community Town of Ithaca Code §270-219 R (1) (c) [8] states requirements for mitigation of aesthetic impacts. Mitigation can include changes to location, height, and design. Alternative Sites Application materials Exhibit I discusses the site selection and alternate sites. Applicant considered five sites, of which one (Ste E) is the proposed site. Four of these sites (A, B, C and D) were dismissed for further consideration by RF because “… this location would not have adequately covered the intended coverage area in the same capacity as the selected location.” No technical evidence was initially provided by Applicant for those conclusions in the record. During the planning board’s meeting on October 2, 2024, Applicant’s RF engineer presented propagation plots to the planning board that showed the alternative sites did not provide the same service levels for low-band RF coverage along Route 79. We recommend that those plots be included in the record to document the reasons for rejecting the alternative sites. If the planning board eventually finds that both a compelling need and a significant gap have been adequately demonstrated by Applicant outside of Town Code limitations or that the provisions of Town Code §279-219 R (2) apply, we recommend further analysis that includes mid-band services RF coverage and capacity issues regarding any rejected sites that appear to have an aesthetic advantage that may provide service to the targeted improvement area. Town of Ithaca Planning Board, October 21, 2024 Page 5 of 5 Minimum Height Applicant provided parametric height analysis for both low-band and mid-band RF coverage at Antenna Center Line (ACL) heights of 140’, 130’, 120’ and 110.’ Since Town Code precludes the use a frequency band that may be preferred by Applicant to justify a significant gap area, we note that absent finding of an existing significant gap in the targeted improvement area or that the provisions of Town Code §279-219 R (2) do not apply, the question of proposed height is moot. If the planning board later finds that there is a significant gap or that Town Code §279-219 R (2) applies, we recommend use of mid-band RF propagation plots and neighbor site “Brookdale” gamma sector LTE capacity data offered in Exhibit H, and/or the drive test and dropped connection data in Exhibit Z to evaluate minimum height justification to address that aspect of minimal intrusion on the community. Design Stealth designs disguise a support structure to blend in with the surrounding area. Stealth designs such as artificial trees or clock towers may be applicable in some cases. In the present case, the proposed tower structure to support the proposed ACL is 134’ which likely precludes effective use of most stealth designs. Other approaches can include use of multiple shorter support structures, co-location on existing shorter structures, distributed antenna systems, and small-cell installations where visual impact is critical. Some design approaches impact RF engineering issues. The applicant has not proposed any such stealth or other mitigation measures at this time. Very truly yours, William P. Johnson RF Engineering Consultant