This issue of “The 911 to the 911” will brief you on the impact and availability of Project 25 for conventional and trunking systems. You’ll also learn the basic differences between the P25 approach to interoperability versus using Internet Protocol (IP). IP is the standard for interoperability in the computer world. For those looking for ways to improve your communication capabilities, we’ll also offer some basic ideas to consider.
1. What is Project 25? 2. P25 Phase II for Trunked Radio 3. Interoperability using IP (Internet Protocol) vs. P25 4. Interoperability Recommendations 5. Project Ideas for Homeland Security Grants 6. Iowa Hospitals / Public Health Radio Network 1. What is Project 25? : P25 Phase 1 is a standard for conventional radio operation. Simply stated, it brings digital features to conventional radio which has been analog. It’s a step forward because digital protocols have historically been proprietary. Proprietary digital systems haven’t allowed users to select products from multiple manufacturers. With the P25 standard, conventional users can continue to mix and match base stations, portables and mobiles from a variety of sources just as they have with analog systems. <Back to top of page> 2. P25 Phase II for Trunked Radio: New York is in the process of purchasing a statewide trunked radio system that is expected to exceed $1B. The impact on the market will be so large that it virtually dictates the P25 standards for Phase II. This affects all of us because the specifications are for a TDMA system, not the current FDMA of Phase I (see below for a comparison). Motorola and M/A-COM both submitted TDMA systems to New York. In fact, Motorola and M/A-Com have also submitted proposals to APCO in an effort to define Phase II standards. Both manufacturers submitted TDMA proposals that are consistent with their proposals to New York. Therefore, Project 25 is in for a major change no matter who ultimately builds out New York. TDMA vs. FDMA? Both are techniques to separate multiple conversation transmissions over a given amount of spectrum, and both are methods to allocate a discrete amount of frequency bandwidth to each user. FDMA (Frequency Division Multiple Access) is a method that allocates full channel bandwidth (currently 25 kHz) to a single user. To double or quadruple the number of simultaneous conversations on a system, channels must be reduced to 12.5 kHz or 6.25 kHz respectively. However, as channel spacing is reduced, the potential for interference increases. 800 MHz channels are currently spaced at 25 kHz. TDMA (Time Division Multiple Access) is a newer method that assigns each caller a time slot for transmission. Increasing the number of simultaneous conversations on a system is accomplished by dividing up the frequency channel (25 kHz) into a greater number of time slots. Advanced compression techniques are allowing more and more time slots to be created without degrading voice quality. Why is a shift to TDMA significant? Project 25 Phase I is being promoted across the industry as a standard for interoperability. What many people don’t realize is that it does not yet address trunking. This shift to TDMA means that folks who have purchased (or are considering) the latest “P25” trunked networks are facing a major unforeseen investment in new infrastructure equipment before trunking is addressed. Is it realistic that everyone that has recently put in a trunked network outside of New York is going to replace it again? Many already expect they have P25 will be shocked. <Back to top of page> 3. Interoperability using IP (Internet Protocol) vs. P25: What is IP? IP is the standard for interfacing computer networks and devices. This same standard is now being used to interface radio networks. It’s already available in a variety of designs and enables radio-to-radio communications across all networks – digital, analog, conventional, trunked, cellular and telephone. The solutions utilize a great deal of existing off-the-shelf, non-proprietary technology that results in better pricing and performance. How is an IP approach to interoperability different than Project 25? IP interoperability solutions allow users of any voice radio system, band, manufacturer or type - trunked or conventional, to communicate with another user of any other type of voice system. An analog, conventional Kenwood VHF radio can talk to an 800 MHz trunked Motorola radio. Each radio stays within the coverage area of its own network and can communicate with other radios working within the coverage area of their own networks. This is different than Project 25. P25 is aimed at enabling different manufacturers’ equipment to work on other manufacturers’ systems. Ideally, this would enable you to purchase radios from more than one manufacturer, and your radios could work on someone else’s P25 system. However, this is limited by band (a P25 VHF radio cannot work on a P25 800 MHz system) and does not yet address trunking. It also fails to provide for interoperability between radio networks. <Back to top of page> 4. Interoperability Conclusions: Project 25 brings digital features to conventional radio while maintaining compatibility between manufacturers. However, it’s a costly alternative to other interoperability options. Analog radios from multiple manufacturers are already compatible and interoperable. Trunked radios even have an analog conventional mode of operation. The current state of Project 25 is limited to the same interoperability capabilities, just in a digital mode. Agencies should contemplate the trade-offs of the digital features to see if they provide value. If the digital features are advantageous, then their conventional systems can be upgraded to P25. Mobiles and portables must also be replaced with P25 radios. If digital voice, unit ID, and some of the other digital features are not critical, why spend the extra money now or on future upgrades? P25 mobiles, portables, base stations and repeaters are all more expensive than their analog counterparts, and the infrastructure you buy won’t provide for P25 trunking. The IP approach to interoperability is proving to be a more secure and compelling investment than Project 25. All investments in existing radio systems are protected. Police and Fire Departments, Emergency Management, Public Works and Schools don’t have to buy new radios to participate. Although this technology has been kept out of our industry longer than other industries, we already have a variety of IP interoperability products available to meet our different applications. The last several industry conferences have emphasized the importance of data and video interoperability in addition to voice. IP is the only logical platform for this level of integration. In fact, radio manufacturers are now talking about an IP backbone to their P25 systems. It’s become evident that interoperability will realistically be accomplished by the IP portion of the system, not P25. By comparison, the cellular industry has not settled on a single standard for all manufacturers. In fact, there’s been hype about TDMA, CDMA, PCS, GSM and a host of other acronyms. But we’ve already learned that it’s not important for your Verizon phone to work on your Sprint network. Rather, it is critical that your Verizon phone can call a Sprint user. This has been accomplished by linking all the networks via IP. In many cases, you’ll find that you won’t even need new technology to achieve interoperability. In Polk County, for instance, they have links from their trunked 800MHz RACOM network to agencies on other systems. They can talk radio-to-radio to fire departments using Kenwood VHF radios, to the Des Moines PD on their conventional system, and to Westcom (West Des Moines, Clive and Urbandale) on a Motorola trunked network. <Back to top of page> 5. Project Ideas for Homeland Security Grants: Looking for project ideas for your grant funding? Here are some communication projects that other agencies are pursuing: Replacing aged base stations and repeaters. Upgrading older push-button consoles to new Windows CRTs Replacing older mobiles and portables Adding voting stations to improve coverage Adding vehicular repeaters AVL/GPS (Automatic Vehicle Locating / Global Positioning Systems) Mobile Data CAD (Computer Aided Dispatch with reporting capabilities) Point-to-Point Microwave Links to eliminate leased telco circuits Wireless LANs / Hot-Spots using 802.11 Replacing logging recorders Adding instant recall recorders Interoperability – Back-up / remote communication centers Sirens / warning Systems
<Back to top of page> 6. Iowa Hospitals / Public Health Radio Network: The hospitals in the State of Iowa are continuing their rollout of a statewide radio communications network. If traditional telephone service is lost, it’s assumed that cellular service would become over-taxed and unusable. This radio network will provide back-up communications for coordinating resources, supplies, physicians, bed availability, etc. It’s a significant part of the Iowa Department of Public Health’s Homeland Security strategy. Approximately one-third of the hospitals have the radios installed, along with the University Hygienic Lab in Iowa City and Poison Control in Sioux City. The remainder of the hospitals will be completed over the next few months. Public Health in each county is also expected to join the network within the next few months. <Back to top of page> 
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