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ViewsLetter on Provisioning        14 Jan 2005          #43

Provisioning automation--from chips to the business layer.


    By V. Kaminsky, Associate Editor

We continue our series on Public Safety Radio. This issue is devoted to
the Project 25, a standard, which is accepted by the U.S. agencies
responsible for public safety and emergencies.

Project 25 (P25) radio is new generation radio, which supports a digital
format and is backwards compatible with existing analog network
infrastructure.  P25 carries voice and data communications, uses
spectrum efficiently, and is easy to use.  Gradual adaptation of P25 by
the U.S. public safety communications community will allow all first
responders to communicate--among agencies  as well as within agencies.


To do their jobs well, Public safety radio users require specific

--Control of group communications and dispatching, with purpose-built
security, dynamic management of talk groups, emergency calls,
talk-around capability (ad hoc calls between handsets without
involvement of a base station),  prioritization of communications, etc.
--"Instant" connections, with voice call set-up time in the range 0.3 to
1 second; 0.5 second often is cited.
--Seamless radio coverage throughout the geographic area, including
guaranteed coverage under the harsh environments of disasters.  Handsets
can relay connections when events take out network base stations. 
--Ability to provision additional radio capacity during major incidents
automatically, while guaranteeing that capacity for rescue and law
--Uncompromising voice quality to allow a listener to recognize the
speaker, regardless of the background noise.

When talking about Public Safety and Security, these functions are

Initially, the Association of Public-Safety Communications Officials,
International (ARCO) led the development with the ARCO Project 25, a
standard for first response radio.  Project 25 is now a joint effort,
with the participation of local, state, and federal governments.  Many
security and technical organizations also support the initiative,
including the U.S. Telecommunications Industry Association (TIA) which
adopted the standards developed through Project 25 and published them as

The primary objectives are to provide high quality digital, narrowband
radios that meet public safety user needs and  maximize
interoperability.  Additional objectives include optimizing radio
spectrum efficiency and ensuring market competition among multiple
vendors based on standards throughout the life of systems.

Although developed in the United States, Project 25 standards were
designed for the global marketplace.  P25 radios are produced for any
VHF or UHF public safety band to economically satisfy agencies with
small number of users.


Project 25 considered various access technologies in an attempt to make
the best use of the available radio frequency spectrum.  Under Phase I
of P25, upgrades moved the existing equipment from analog technology
with a 25 kHz bandwidth to digital technology with a 12.5 kHz bandwidth.
The modulation selected for Project 25 is C4FM, which is a modified,
four-level, frequency-shift keying (FSK), with a raised cosine filter to
minimize inter-symbol interference.  TIA-102 requires new equipment to
be "backward compatible" with the analog equipment to allow for a smooth

In Phase II, more spectrum-efficient equipment using Frequency and Time
Division Multiple Access (FDMA and TDMA)  will need no more than 6.25
kHz per voice channel.  This equipment will also be backward compatible
with Phase I.  Additionally, P25-II allows support compatibility with
TETRA radios (originally Trans-European Trunked Radio, renamed
Terrestrial Trunked Radio).

Project 25  defines both Trunked and Conventional operating modes for
Digital Two-Way Radio.  It offers much richer set of features than
traditional FM radio and gives the immediate advantage that voice can
easily be encrypted, and mixed with other data transmissions.

Project 25 mission includes these key digital standard attributes:

--Backward compatibility and graceful migration.  Project 25 enables
system migration, which is backward compatible with existing public
safety communications systems, and allows forward compatibility with
next-generation radios.  These features contribute to...
--Interoperability.  With all phases compatible, Project 25 promotes
communication among groups in an agency, among  agencies (local, state,
and federal), and with neighboring jurisdictions.  This is important for
mutual aid where resources are gathered from many different sources.  
--Scalable Trunked and Conventional capabilities.  Project 25 systems
scale from a single channel (conventional) to  high-capacity trunking of
many voice channels on one RF carrier via frequency division
multiplexing (FDM).  Trunked radios add a number of features, such as
priority call, and they can be configured in voting, multicast, and/or
simulcast communications, and still include the talk-around capability
required by public safety agencies.  Of course, these advantages affect
the cost.
--High-level security

The Project 25 standards has the following major objectives:

--Obtain maximum radio spectrum efficiency:  system migration from 25
kHz to 12.5 kHz and then 6.25 kHz or equivalent spectral efficiency to
support more calls and more users without more RF spectrum.  
--Ensure competition in system life cycle procurements:   choice among a
variety of vendors and solutions to keep costs competitive and maximize
--Provide "user friendly" equipment:  ease of use, minimal training
costs, and a shorter learning curve so users quickly can take advantage
of all system features to enhance their productivity. 
--Rapid Deployment:  creation of active voice and data networks at
emergency sites, with or without the presence of base stations.
--Support both digital and analog testing:  although common in the
cellular world, this is a new requirement in the public safety
communications environment.

In addition to the voice encoding method, the P25 specifications define
the following open interfaces and equipment definitions.  Any
manufacturer could supply equipment on either side of these interfaces:
-Common air interface (CAI)
-RF sub-system
-Inter-system interface
-Telephone interconnect interface
-Network management interface
-Host and network data interfaces.

Implementations can take the form of software-defined radios, which
means the same hardware can in principal upgrade from phase 1 to phase 2
and possibly later versions with new firmware.

-- Call us for a vendor-neutral network architecture and strategy for
expansion or convergence.  We know voice AND data--and how to avoid
expensive bear traps on the migration path, such as security
--Working on product positioning or a marketing message for telecom?
Yes, we've done that--for hardware products and carrier services.
--Need an Expert Witness?  Associates at Flanagan Consulting have aided
in many legal proceedings involving telecom intellectual property and
--For RFP preparation, bid analysis, proposal evaluation--call us.  We
have current experience in Federal network procurement processes that produced a network award without a formal protest.

"In Converged Networking, We Have the Experience."

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best source for communications tutorials and white papers.

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