Concepts to Reality

e-mail: masoncom@masoncom.comwww.masoncom.com

Nick Smye

15 February 2000

Presentation to

TETRA BUSINESS SYSTEMS GROUP

AN INTRODUCTION TO THE PEI

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FORMAT

1. Introduction to Mason Communications

2. Radio Peripheral Interfaces

3. PEI Overview

4. AT Command Set

5. PPP/TNP1 Command Set

6. Current Status of PEI

7. Conclusion

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INTRODUCTION TOMASON COMMUNICATIONS

• Telecoms and IT Consultancy

– What is our TETRA Experience?

• Worked with Home Office on PSRCP since 1994

– Business Case Phase

– Project Definition Study Invitation to Tender

– User Service Level Requirements

– Project Definition Study Phase

• Greater Manchester Police - Business drivers for

TETRA

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INTRODUCTION TOMASON COMMUNICATIONS

• Lancashire Constabulary - Pilot Assurance Support

• States of Jersey Police

– Validation of pilot system

– Re-validation after upgrade

• European GSM Operator – assistance with RFP to support a Public TETRA Licence Bid

• Technical Advisers to PITO

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RADIO PERIPHERAL INTERFACESRadios and Peripherals

• In early days (pre-trunked), professional radios tended to be specialised and expensive

• Peripherals limited and manufacturer specific

– Remote microphone

– Earphones/Headsets

– Speakers

• Some peripheral specialists

– Products ordered to a specific interface (££ + time)

– E.g. Handsfree mic

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RADIO PERIPHERAL INTERFACES Trunked Radio

• Introduction of trunking with standard and open systems (MPT 1327/MPT1343)

• Radio offers access to powerful new functionality (speech+ status/short data/data)

• System performs Dynamic Channel allocation

• Applications are now able to to use these features…plus access to radio

• BUT.. How do we access these features in a non-proprietary manner?

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RADIO PERIPHERAL INTERFACES MAP27 Interface Standards

• Initially some manufacturers used proprietary interfaces

– Applications manufacturer specific

– Fleets with more than one manufacturer

• Open standard, MAP27, published in 1992

• Most manufacturers support it

• Defined interface (RX,TX GND) and Layered Protocol

• Data Link Layer uses a block format, delimited by control characters

• Allows simultaneous operation (e.g. RSSI check during a data call)

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RADIO PERIPHERAL INTERFACESMAP27

Physical Layer

Terminal Radio

Network Layer

Network Layer

• Status

• Short Data

• Voice and NPD

• Modem Call

• Connection Clear

• Diversion

• Radio Control

Data Link Layer

Data Link Layer

• Blocks delimited by Control Characters

• Provides Block Transport

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RADIO PERIPHERAL INTERFACES What is the GSM Approach?

Base GSMGSM 07.07

SMSGSM 07.05

GPRSGSM 07.60

PPP command Based

All AT command Based

• Call Control• Network Service• Mobile Equipment Control and Status

AT and Block

• Message Retrieval and Transmission• Hex Encoded Binary• Block mode – similar to MAP27

• X25• PPP• IHOS• AT• PPP Dial In Compatibility

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PEI OVERVIEWTETRA – Open Standards Based

Architecture

I4

I4’

GATEWAYSOMC

BSSNSS

TETRA 1

PSTNISDN

PTNPDN

DEFINED INTERFACESI1 Radio air interfaceI2 Line station interfaceI3 Inter-system InterfaceI4 Terminal equipment interface (MS & TE)I4’ Terminal equipment Interface (LS & TE)I5 Network Management InterfaceI6 Direct Mode radio air interface

I1I2

TETRA 2I3

NetworkManagement

NetworkManagement

I5I6

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PEI OVERVIEW Peripheral Equipment Interface

• Defined Standard for access to:

– Data

– Set-up and Control of Voice Calls

– Radio Specifics (e.g. battery status)

– User Applications in Radio

• Standard Physical Interface (?)

• Minimal Extra Software in Terminal ( Driver)

• Max compatibility with GSM

• Still in draft

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PEI OVERVIEW Physical Connection

• Physical layer V24/V28

– D type (RX,TX,GND)

– RJ11/RJ45

• Other Serial Form Physical Layers can be used where Appropriate

– Infrared (GSM?)

– Ethernet

– Bluetooth?

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AT Commands PPP Commands

PEI PROTOCOLS

PEI OVERVIEW PEI PROTOCOLS

Short Data

Circuit Mode Data

Radio Functions

IPv4

IPv6

Packet Data

Speech CC

SDS

Radio Config & Status

Supplementary Services

CM Data

Radio Remote Control

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AT COMMAND SETCommands

• AT Commands well known in Industry

• “+C” prefix reserved for Digital Cellular

• PEI AT Commands Based on:

– Cellular DCE Control

– PCCA Wireless Modems

– TETRA Specific

– SDS (very similar to GSM)

– Radio Control

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AT COMMAND SETTypical Applications

• Those suited to small data transfers using TETRA SDS

– Type 1 – 16 bit

– Type 2 – 32 bit

– Type 3 – 64 bit

• Type 4 – up to 2039 bits (Advanced Link recommended for user data longer than approx. 133 Octets)

• Short Data Transfer Layer (SDS-TL)

– Built on top of SDS Type 4

– Provides end to end acknowledgment

– Store and Forward

• Typical Application - AVL

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AT COMMAND SETLimitations

• Terminal is either in Command State or On-line Data State

– In On-line Data state, no other communication with radio is possible (e.g. battery state)

• Usefulness is limited to SDS, Circuit Mode Data

– What support for CM data?

• No current support for voice calls

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AT COMMAND SETAdvantages

• Simple to implement

• No need for TCP/IP stack and PPP layer

– Reduces terminal’s complexity, memory requirement

– Reduced Power consumption

• Easy to debug

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PPP/TNP1 COMMAND SETWhat is PPP?

• Point-to-Point Protocol

• Standard Internet (IETF) Open Protocol

• Standard method of transporting multi-protocol datagrams over point-to-point links

– Method for encapsulating multi-protocol datagrams

– Link Control Protocol for establishing, configuring and testing the link

– Family of Network Control Protocols for establishing and configuring the Network Protocols that run over PPP

• THE standard for PCs for dialup internet (IP) access

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PPP/TNP1 COMMAND SET PPP Frames

• 0xC021 Link Control Protocol – establishes, maintains and ends PPP

• 0x0021 IP Protocol

• 0x8021 Internet Protocol Control Protocol – establishes configures and terminates the TCP/IP session

• 0x0287 TETRA Network Protocol 1

• 0x8287 TETRA Network Protocol 1 Control Protocol

Frame Start Frame EndProtocol DATA Padding FCS

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TNP1

PPP/TNP1 COMMAND SET PPP Mode Structure

LCP

TCP/IP

IPCP

PPP Frame

TNP1CP

PPP Frame

PPPPPP FramePPP

RS232

NetworkLayer

Data LinkLayer

DATA RADIO CONTROL

User Terminal

RADIO

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PPP/TNP1 COMMAND SET IP Protocol

• IP provides the means of transporting the application data

• IP is universally used

• IPv4 and IPv6 Supported by PEI Specification

• Provides for standard interconnection at the SwMI to external IP networks (e.g. host computer) via router/gateway

• BUT not as efficient as SDS for transfer of short messages

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PPP/TNP1 COMMAND SET TNP1 Protocol

• This provides the means of setting up calls and controlling the radio

• No equivalent functionality in existing Internet Specifications and so this is unique to TETRA

• Uses standard PPP frames with a TNP1 Protocol number (0x0287)

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PPP/TNP1 COMMAND SET TNP1 Commands

• Radio Control and Call set-up

– Priority

– Group Attachment

– SDS

– Duplex/half duplex

– Energy Saving Mode

– Etc.

• Allows proprietary defined information to be sent and received from radio

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PPP/TNP1 COMMAND SET TETRA PEI PPP Issues

• PPP must be used for TETRA Packet Data Services

• No manufacturers are currently supporting IP packet data

• PPP/TNP1 complex to implement in radio and terminal

– Memory

– Power consumption

– Development effort

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CURRENT STATUS OF PEI

• Still under draft

• Complex standard – TETRA MOU have proposed a subset of the AT commands

• PPP/TNP1 support awaiting rollout of Packet Data?

• What is the current level of support?

• Are all manufacturers going to support it?

• Will the widespread adoption of GPRS influence TETRA?

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CONCLUSION

• PEI Standard defined for TETRA Terminals

• AT and PPP modes

• AT simple and suited to small data requirements

• PPP complex but powerful – the only choice for packet data

• What is the support from the manufacturers and the timescales?

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• Military

• No access to CODEC

• SDS-TL

• IP overhead vs SDM?

• AT/Radio turnon

• Suppl Serv?

• Voice call using AT?

• IP When

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CASE STUDY -Public Safety Radio Communications Project

• Business Case Phase

– Evaluation of suitable systems

– Technical input to Business Case

• Project Definition Study Invitation to Tender

– Functional Specification

– Terms of Reference

• User Service Level Requirements

– Service Level Template and Guide

• Project Definition Study Phase

– Ongoing review of Study Products

– Review of FDS and Operational Trials.

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PUBLIC SAFETY RADIO COMMUNICATIONS (PSRCP) PROJECT

• Home Office - Technical Advisers

• Greater Manchester Police - Business drivers for TETRA

• Lancashire Constabulary - Pilot Assurance Support

– Terminal & Peripheral Equipment

– Integrated TETRA Radio & Telephony

• Hampshire Police - Impact of PSRCP Appraisal

• Cheshire Constabulary - Assurance Support.

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PUBLIC SAFETY RADIO COMMUNICATIONS (PSRCP) PROJECT

• Home Office - Technical Advisers

• Greater Manchester Police - Business drivers for TETRA

• Lancashire Constabulary - Pilot Assurance Support

– Terminal & Peripheral Equipment

– Integrated TETRA Radio & Telephony

• Hampshire Police - Impact of PSRCP Appraisal

• Cheshire Constabulary - Assurance Support.