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Hawaii Preliminary Technical Assessment ICTAP-HUHA-PREASSESS-001-RO to offer a multiband portable radio capable of supporting a combination of the VHF, UHF, and 700/800 MHz bands. Several of these radios have been used on various systems around the country while others are relatively new to the marketplace. Vendors offering P25 subscriber radios include Motorola, M/A-COM, Kenwood, EFJohnson, Tait, Thales, Icom, Vertex/Standard and BK/Relm, providing several options and competitive pricing far any new radio procurement, although not all support trunking. It should be noted that there are multiple optional features radio manufacturers can offer in their P25 radios. A lack of commonality of these features can have a negative impact on interoperability. For example, P25 currently supports DES-OFB and AES encryption. If implemented in the infrastructure, all P25 subscriber radios must have the same optional encryption algorithm enabled in order to support secure communications. For more information regarding standardized P25 features refer to the P25 Features Matrix located on the PTIG website (www.oroiect25.oro). It's important to note that there are several additional P25 features of interest that have not yet been defined within the P25 standards but are planned for future development. These features are not included in the P25 Features Matrix. Over-the-air-programming (OTAP) is one such example. Until an undefined feature is standardized, manufacturers may provide proprietary implementations of the feature to allow the service to be provided to the end user. These proprietary implementations will not allow for interoperability of these respective features across multiple vendors. When the County of Hawaii representatives look to buy new P25 subscriber radios, there are a few recent upgrades to the P25 standards to be aware of prior to purchase. The first is the adoption of a new enhanced full-rate vocoder for Phase 1 to replace the existing full-rate vocoder. The improvements are intended to address degraded voice quality issues identified in the field caused from self-contained breathing apparatus (SCBA) and other common fire ground noise. This issue was briefly mentioned in section 2.1.1. Some P25 manufacturers currently use the new vocoder while others plan to implement it in the future. The second upgrade relates to the changes necessary for .:subscriber radios to fully support ISSI roaming. The P25 standard was recently modified and current subscribers may not fully support the changes. ICTAP recommends consulting with selected manufacturers on how their respective subscriber units support both of these recent upgrades. 2.6 Voice Communications Recommendations Frequency Band Selection The Macro Conceptual Design Analysis 8 Recommendation Report recommends the County adopt a P25 trunked system operating in the 700 MHz band. There are concerns and complications involved with choosing to stay in the VHF band or migrating to either 700 or 800 MHz. We disagree with the Macro assumptions that digital VHF would not be favorable to wide area and portable coverage and venders do not support VHF multicast P25 trunking. There are at least five vendors that provide trunked P25 VHF multicast systems and at least three of those also support VHF simulcast. We do agree that there would be additional frequency pairing concerns and system migration concerns using the VHF spectrum. The Macro Conceptual Design Analysis & Recommendation Report dismissed the thought of using VHF and recommended a migration to 700 MHz with very little consideration of 800 MHz. All of the adjacent counties are presently operating proprietary-protocol 800 MHz systems. If the County had 800 MHz capable subscriber units then County assets could deploy to other counties throughout Hawaii and operate on 800 MHz interoperability channels in the NPSPAC band. Likewise the other counties would be able to support the County of Hawaii if the County or State fielded an interoperability system using 800 MHz NPSPAC channels on the Island. The 800 MHz interoperability system could be deployed regardless of the frequency band that the County of Hawaii chooses for its new system. There is a potential for the State to install a 700 MHz P25 system on the island. At the present time all subscriber units for 700 MHz are being developed as dual band (7001800) capable. If the County October 2008 11