Spokane Regional Communication System Overview By Scott Grimmett of Industrial Communications

Present Communication System  Spokane's public safety radio system consists largely of a conventional VHF systems. The systems are nearly all operating as wideband systems, with some infrastructure recently purchased and some as old as 30 years. Mobile and portable radios are generally newer, with some agencies operating equipment up to 15 to 20 years old. City of Spokane, WA RFP #P6587

Need for Replacement System  Present VHF systems are in relatively poor condition, as are the radio facilities. There is less area coverage present in the systems than user agencies need. Some equipment in first line service is 15 to 20 years old and in some cases, the equipment lacks modern radio system features and capabilities. City of Spokane, WA RFP #P6587

New Spokane Radio System  The Spokane region is embarking on a multi-year process of design, developing and bringing to operational status a multi-agency, integrated wireless system that will support effective voice and data communications for first responder agencies. City of Spokane, WA RFP #

Cost and Funding  The first phase of the system is expected to cost between $40 to $45 million with a $1 million dollar annual maintenance cost.  Funding will be through government grants and a 1/10 of 1% county sales tax.

Spokane Regional Communication System Simulcast VHF System Development

First Stage Next Generation System Development  A new wide area simulcast repeater- based VHF radio channel is currently being constructed.  This simulcast channel will operate initially as a 12.5 KHz narrowband analog channel, with future upgrade to digital operation.

Simulcast System Development  This simulcast channel will make use of the Spokane County Sheriff's Office "Phone" channel, presently licensed on base TX and base RX.  The simulcast channel will consist of seven transmit/receive sites with three additional locations as receiver-only sites.

Simulcast System Map

What is Simulcast?  Simulcast is the simultaneous broadcast of a transmission by multiple repeater sites all using the same radio frequency.  Simulcast is the simultaneous broadcast of a transmission by multiple repeater sites all using the same radio frequency. These simultaneous broadcasts from multiple transmitters can have overlapping areas.  Mobile users are able to hear every message from the dispatcher regardless of their location and without changing channels.

Spokane Simulcast System Example

Simulcast Overlap  The figure below shows a voice simulcast system with three repeaters on the same RF frequency. Overlap areas are those areas where signals from more than one transmitter site are strong enough to provide reception.

Overlap Areas   Critical area in a simulcast system.   A slight degradation in audio quality may occur in the overlap areas.   Additional engineering and equipment cost is needed to design the overlap areas.

Spokane Regional Communication System 700/800 MHz P25 Trunked System

System Selection  Based on the very limited availability of VHF and UHF radio spectrum in eastern Washington and topography that increases the likelihood of co- channel and adjacent channel interference to wide area VHF and UHF radio, the Spokane region plans to develop a regional 700/800 MHz Trunked P25 Digital Radio System.

P25 Digital Radio Standard  Project 25 (P25) refers to a suite of standards for digital radio communications for use by federal, state/province and local public safety agencies in North America to enable them to communicate with other agencies and mutual aid response teams in emergencies.

Why 700 MHz?  It’s all about spectrum.  Low Band, VHF, UHF, 800 MHz Band Approximately 23 MHz of spectrum in totalApproximately 23 MHz of spectrum in total 941 Channels941 Channels  700 MHz 24 MHz of spectrum24 MHz of spectrum 3,480 Channels3,480 Channels

Public Safety Radio Spectrum

What is trunking?  Unlike a conventional system, frequencies are not dedicated to any particular group of users. Instead, a large pool of frequencies is shared among a larger number of users.  A trunked radio system does this by taking advantage of the fact that not every user will want to transmit at any given time.   Trunking is accomplished by automatically sharing channels in a multiple repeater system.

Trunking System  For example, a county trunked system could have 10 frequencies shared among 20 agencies such as police and fire departments, road crews, buses, dog catchers, EMS, etc.

Trunking Example

System Users  All Spokane County Fire/EMS, law enforcement, and general government agencies will move to the 700/800 MHz P25 trunked system.  Additional users from within regional local government may use the system and have responsibility for funding their participation on the system. Similarly, outside agencies in neighboring counties, within Washington and Idaho as well as Federal and commercial organizations may make limited use of the system.

Feature Set  Roaming across the entire area without need for the user to switch channels.  Hundreds of independent user groups available.  Capability to disable a stolen radio from dispatch.  PTT caller identification.  Over-the-air radio programming.  Voice encryption.  Private calls.  Emergency call alert.

Coverage  Will exceed that of the current VHF system.  For all county, 95% on-street portable coverage.  Suburban areas, 95% in-building portable coverage assuming medium density structure.  Urban areas, 95% in-building portable coverage assuming high density structure.

Subscriber Equipment  First responder subscriber equipment will be high or mid-tier.  Models will Support both 700 and 800 MHz operationSupport both 700 and 800 MHz operation Compliant with Mil. Spec 810Compliant with Mil. Spec 810 Support all encryption modesSupport all encryption modes Support P25 digital feature setSupport P25 digital feature set

Subscriber Units  P25 Digital Trunked Radio Portable: $2000 to $7000 per radio.  P25 Digital Trunked Radio Mobile: $2500 to $10,000 per radio.  Large, heavy, and complicated.

Spokane Regional Communication System Interoperability

Simulcast Strategy  The simulcast channel is designed to patch-in agencies with VHF radios to all Spokane County Fire/EMS, law enforcement, and general government agencies moving to the 700/800 MHz P25 trunked system.

Spokane System Simulcast with 700 MHz Trunking Example

Simulcast System Growth  It is anticipated that the simulcast system will grow to include additional mutual aid channels, such as the state/local VCALL/VTAC and UCALL/UTAC channels or similar federal resources, as well as a few VHF and UHF channels.

Proposed VHF Mutual Aid Channels R Mutual Aid 1 VHF simulcast channel being constructed VHF simulcast channel being constructed R Mutual Aid 2 VHF simulcast channel R Mutual Aid 3 VHF simulcast channel R Mutual Aid 4 (VCALL) 1-3 transmit sites with receive voting R Mutual Aid 5 (VTAC) 1-3 transmit sites with receive voting R Mutual Aid 6 (LERN) 1-3 transmit sites with receive voting R Mutual Aid 7 (REDNET) 1-3 transmit sites with receive voting

Other Proposed Mutual Aid Systems  Two UHF narrowband simulcast systems will be deployed on the UCALL and UTAC channels. This will use 7 TX sites and 10 RX sites.  The county will develop an enhanced the ICALL and ITAC analog system using 800 MHz frequencies.

Desired capabilities  Support for legacy VHF and UHF systems.  Connectivity with the airport, department of corrections, tribal law enforcement, AMR, NW Medstar, and Deer Park Ambulance.  Connectivity with adjoining county P25 systems.  Connectivity with Spokane Transit.  Connectivity with Kootenai 700 MHz P25 trunked system.  Integration with Fairchild Air Force base.  Link with systems in neighboring counties.  Integration with future Washington statewide trunked and conventional systems.

Spokane Complete System  Using the interoperability part of the system, radios users inside and outside the county will be able to communicate with dispatch and other users regardless of the radios frequency, mode, or manufacturer.