Nick Smye

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Presentation toTETRA BUSINESS SYSTEMS GROUPAN
INTRODUCTION TO THE PEI

• Nick Smye
• 15 February 2000

Concepts to Reality
e-mail masoncom_at_masoncom.com
www.masoncom.com
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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

• Terminal Peripheral Equipment
• Integrated TETRA Radio Telephony

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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

(e.g. Sonic)
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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
  featuresplus 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)

• ESI Case

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RADIO PERIPHERAL INTERFACES MAP27

• Status
• Short Data
• Voice and NPD
• Modem Call
• Connection Clear
• Diversion
• Radio Control

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RADIO PERIPHERAL INTERFACES What is the GSM
Approach?
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

PPP command Based

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

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PEI OVERVIEWTETRA Open Standards Based
Architecture
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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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PEI OVERVIEW PEI PROTOCOLS
Radio Remote Control
Packet Data
Short Data Circuit Mode Data Radio Functions
IPv4 IPv6
Speech CC SDS Radio Config Status Supplementary
Services CM Data
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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

• ARDxx voice in GSM audio routing man specific

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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 terminals 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

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PPP/TNP1 COMMAND SET PPP Mode Structure
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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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Presentation Title Date
Mason Communications Ltd 5 Exchange
Quay Manchester M5 3EF England
Client
Tel [phone] Fax [phone]
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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.