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RADIO NETWORK TRUNKING

Introduction

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MPT 1327 - What is it?

• MPT 1327 is one of many specifications relating to radio equipment for use in the United Kingdom. (MPT stands for Ministry of Post and Telecommunications) • The standard details the operation of an automatic trunked radio network using conventional narrow band FM radio channels.

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Radio Trunking

• What is meant by trunking?

• Trunking is the sharing of resources • All available channels are utilised to the best advantage.

• Applied to radio systems, this means the sharing of available radio channels.

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Conventional Radio System

Repeater Tf1 Rf2 Repeater Tf3 Rf4 Repeater Tf5 Rf6 F Y L D E M I C R O S Y S T E M S

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Trunked Radio System

SIO BUS Fylde TSC

Repeater Tf1 Rf2 Repeater Tf3 Rf4 Repeater Tf5 Rf6

Fylde TSC

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Conventional Vs MPT Trunked Systems

• Efficient utilisation of frequencies.

• Automatic supervision of all calls • Greater immunity to system failures • Increased facilities • Larger range of compatible radio equipment (compared to selective calling systems) • Simplicity of Operation

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System Access

– Conventional Radio • Channel must be monitored for activity. Co-Channel users must clear before the next call is made.

– Trunked Radio • In the Fylde MPT trunked radio systems the required party identity is selected by the calling party and the call is initiated, with the system then taking control and connecting the call onto a free talk channel.

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Privacy

– Conventional Radio • Privacy is not fully possible as all users can share the same RF channel. Privacy is not practical as the channel is monitored for access when free. Coded squelch can be used to reduce over talking.

– Trunked Radio • Users in a call have exclusive use of the talk channel for the duration of the call. Only the call parties are tuned to the RF talk channel. It is also possible to provide speech encryption on the radio network.

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Trunked Radio System Benefits

• Efficient use of the RF spectrum • Privacy • Advisory system status messages • Automatic call connections • Subscriber call authorisation • Call limit timing and management • Automatic system fail soft and standby mechanisms

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Fylde MPT System Facilities

10 • Local and Intersite speech and status calls.

• Local and optionally Inter-site group speech and short data calls.

• Inter-fleet and Inter-prefix calls.

• Radio to PABX/PSTN and PABX/PSTN to radio unit speech calls.

• Call diversion.

• Non Prescribed Data messages.

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Fylde System Management Facilities

• Variable individual and user group facilities, coverage areas and priorities.

• Dynamic call timers on a time and day of week programmable basis.

• Call billing and traffic statistics.

• Remote alarm and maintenance facilities.

(all above facilities require SCI and SYSCON)

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Supported Call Types

• Speech Calls – Mobile to mobile – Mobile to PABX – Mobile to PSTN • Status calls (pre-defined status codes) • Short Data – Messages up to 23 chars (GPS Systems) • Long Data

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Plus....

• AVLS • Call Diversion • Group Calls • Called in absence • Pre-emptive Emergency Calls • Priority Calls

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