«ICS: 33.020 Key words: radio, TETRA Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Designers' guide Part 3: Direct Mode Operation (DMO) ...»
ETSI ETR 300-3
TECHNICAL February 2000
Source: TETRA Reference: DTR/TETRA-01011-3
Key words: radio, TETRA
Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D);
Part 3: Direct Mode Operation (DMO) ETSI European Telecommunications Standards Institute ETSI Secretariat Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE Internet: firstname.lastname@example.org - http://www.etsi.org Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16 Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2000. All rights reserved.
Page 2 ETR 300-3: February 2000 Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to "ETSI Standards Making Support Dept." at the address shown on the title page.
Page 3 ETR 300-3: February 2000 Contents Foreword
3 Definitions and abbreviations
4 What is direct mode and why do we need it?
4.2 Frequency of operation
4.3 Managed Direct Mode
4.4 Direct Mode on European shared harmonised spectrum
5 Direct mode services and facilities
5.1 Service definitions
5.1.2 Bearer service
5.1.3 Intrinsic service
5.1.4 Summary of tele/bearer services offered in TETRA DMO
5.2 Direct mode teleservices
5.2.1 Individual call
5.2.2 Group call
5.3 Direct mode bearer services
5.3.1 Circuit mode unprotected bearer services
5.3.2 Circuit mode protected bearer services
5.3.3 Short data service (SDS)
5.4 Intrinsic services
5.4.1 DM late entry
5.4.2 Transmitting party identification
5.4.3 Emergency calls
6 Description of direct mode equipment types
6.2 Direct mode mobile station (DM-MS)
6.3 Dual watch mobile station (DW-MS)
6.4 Direct mode repeater (DM-REP)
6.5 Direct mode gateway (DM-GATE)
6.6 Direct mode repeater/gateway combination (DM-REP/GATE)
6.7 Direct mode power classes
6.8 Limitations imposed by the physical layer for direct mode type equipment
7 Direct mode operational examples
7.2 MS to MS communication with Dual Watching
7.3 DMO communication via a repeater with Dual Watching
7.4 Gateway operation
7.5 Direct mode repeater/gateway operation
8 Basic direct mode MS-MS protocol
8.1 Testable boundaries
8.2 DM protocol layering
8.3 Direct mode functionality
Page 4 ETR 300-3: February 2000 8.4 Physical resources
8.5 Slot timing diagrams
8.5.1 Constraints on the frame structure (including synchronisation)
8.5.2 Direct Mode operation
8.6 Call set-up protocol
8.6.1 Call set-up without presence check
8.6.2 Call set-up time (fundamental constraints)
8.6.3 Call set-up with presence check
8.6.4 Late entry
8.6.5 Channel reservation and changeover in a call
8.6.6 Pre-emption of a DM call
8.6.7 Terminating a call
8.7 Channel surveillance
8.8 Battery economy
8.9 Frequency efficient operation
9. Implementation and operation issues affecting dual watch
9.2 Basis for dual watch operation
9.3 Implementation of dual watch operation
9.3.1 Switching from idle to active
9.3.2 Switching from active to active
10. Security features
10.1.1 Mobile to mobile operation
10.1.2 Dual Watch Operation.
10.1.3 Gateway mode operation
10.2.1 Air Interface (AI) encryption
10.2.1.1 Cipher Key
10.2.1.2 The Time Variant Parameter (TVP).
10.2.2 End-to-end encryption
10.3 Key Management.
10.3.1 Air Interface Encryption keys.
10.3.2 End to End Encryption keys.
10.3.3 Over The Air Re-keying (OTAR)
10.4 Secure Enable and Disable
11. Radio Aspects
11.1 DMO deployment constraints
11.2 Transmitter noise
11.4 Effects of transmitter noise and blocking
11.5.2 Calculating the effect of transmitter noise
11.5.3 Calculating the effect of blocking
11.5.4 Allowing for a noise floor uplift
11.5.5 Translating path losses into distances
11.6 Example 1 - wanted signal at extremity of range, unwanted interferer close by............... 53 11.6.1 Step 1 - Calculate allowable noise
11.6.2 Step 2 - Translate allowable noise into path loss and stay-away distance... 53 11.6.3 Step 3 - Calculate path loss and stay-away distance for blocking................ 53
11.7 Example 2 - wanted signal at close range, unwanted interferer close by
11.7.1 Step 1 - Calculate noise floor uplift
11.7.2 Step 2 - Calculate allowable noise
11.7.3 Step 3 - Translate allowable noise into path loss and stay-away distance... 54 11.7.4 Step 4 - Calculate path loss and stay-away distance for blocking................ 54
11.8 Unwanted transmission noise versus blocking
11.9 Variation of stay-away distance with transmitter power and frequency separation........... 56
11.10 Effect of assumptions
11.11 Implementation issues
Page 5 ETR 300-3: February 2000 Annex A (normative): Teleservices, bearer and supplementary services supported by TMO/DMO.....59 Annex B (informative): Support of security features
B.1 Time Variant Parameter
B.2 Synchronisation of end-to-end encryption
Annex C (informative): Short range propagation models used in the co-existence studies
C.2 Free space propagation
C.3 Wickson model
C.4 CEPT SE21 model
Annex D (informative): RF channel selection, numbering and addressing
D.3 Addressing in repeater and gateway direct mode operation
Annex E (normative): TDMA frame and slot structure for direct mode operation
E.1 Frame structure
E.2 Timeslots and bursts
Annex F (normative): DM support for short data messages
F.1 DM short data call
F.2 Unacknowledged short data message
F.3 Acknowledged short data message
Annex G (informative): Bibliography
Page 6 ETR 300-3: February 2000
Foreword This ETSI Technical Report (ETR) has been produced by the Terrestrial Trunked Radio (TETRA) Project of the European Telecommunications Standards Institute (ETSI).
ETRs are informative documents resulting from ETSI studies which are not appropriate for European Telecommunication Standard (ETS) or Interim European Telecommunication Standard (I-ETS) status. An ETR may be used to publish material which is either of an informative nature, relating to the use or the application of ETSs or I-ETSs, or which is immature and not yet suitable for formal adoption as an ETS or an I-ETS.
This ETR consists of 5 parts as follows:
Part 1: "Overview, technical description and radio aspects";
Part 2: "Radio channels, network protocols and service performance";
Part 3: "Direct Mode Operation (DMO)";
Part 4: "Network management";
Part 5: "Guidance on Numbering and addressing".
Page 8 ETR 300-3: February 2000
1 Scope This guide is written as a "Read-me-first" manual or "Getting started with TETRA DMO". It is not intended to be a guide to the TETRA DMO standard nor an authoritative interpretation of the standard. If any conflict is found between this guide and the corresponding subclauses in the TETRA standard then the standard takes precedence.
The aims of this guide are:
- to provide the reader with sufficient knowledge to engage in qualified discussions with the equipment and service suppliers;
- to expose the reader to the specific language and technical terminology used in the standard;
- to enable the reader to understand the flexibility in system design, system network topography, system availability, various modes of operation and security features;
- in the Radio Aspects part of the guide, sufficiently detailed design information is given to allow link budget calculations to be carried out and outline radio coverage planning to be performed. Some preliminary calculations are also given for co-existence between trunked and direct mode terminals and also for the number of direct mode talk groups (Nets) that can operate simultaneously at the same location.
The scope of this first edition of the DMO Designers' Guide is limited to examining in detail mobile station to mobile station direct mode operation. The basic mobile station operation is placed in the wider context of direct mode operational requirements by outlining repeater and gateway functionality. However detailed consideration of repeaters and gateways will be dealt with in a later edition.
It should be understood that, as in all standardisation activities, there is an inherent conflict between the Users' wish to have as broad a standard as possible and at the same time wanting to have as much of that broad standard available and implemented right from the beginning of service. Potential equipment purchasers, network operators and service users must make sure they influence the suppliers to have their required functionality available when they need it.
Equipment manufacturers will use the broad flexibility provided within the standard to develop and implement equipment in various ways, and still be conforming to the standard. This broad availability of equipment, each optimised around certain features and functionalities, needs to be carefully analysed by network operators and system users to find the supplier with equipment suited best for their needs.
For the purposes of this ETR, the following references apply:
For the purposes of this ETR, the following terms and definitions apply:
call: there are two types of call, individual call or group call. An individual call using a gateway is a complete sequence of related call transactions between a DM user and a user on the V+D network (or accessed via the V+D network). There are always two participants in an individual call. A group call is a complete sequence of related call transactions involving at least two or more DM-MSs. The number of participants in a group call is not fixed, but is at least two. Participants may join (late entry) and leave an ongoing group call.
call transaction: all of the functions associated with a complete unidirectional transmission of information during a call. A call is made up of one or more call transactions. In a simplex call these call transactions are sequential.
called user application: user application which receives an incoming call.
calling user application: user application which initiates an outgoing call.
changeover: within a call, the process of effecting a transfer of the master role (and hence transmitting unit) at the end of one call transaction so that another can commence.
Direct Mode (DM): mode of simplex operation where mobile subscriber radio units may communicate using radio frequencies which may be monitored by, but which are outside the control of, the TETRA V+D network. DM is performed without intervention of any base station.
DM Call Control (DMCC): layer 3 entity responsible for setting up and maintaining a call in DMO.
DM channel: specific grouping of timeslots in the DM multiplex structure related to a particular DM RF carrier i.e. DM frequency (or to a pair of duplex-spaced RF carriers for operation with a type 1B or type 2 DM-REP or a type 1B DM-REP/GATE). The grouping may not always be fixed, but in DMO when operating in frequency efficient mode as an example, there are two DM channels, identified by the letters A and B.
Direct Mode Mobile Station (DM-MS): physical grouping that contains all of the mobile equipment that is
used to obtain TETRA DM services. A DM-MS may have one of three states:
- Master: if the DM-MS is active in a call transaction transmitting traffic or control data;
- Slave: if the DM-MS is receiving traffic and/or signalling in a call;
- Idle: if the DM-MS is not in a call.
DM-REP presence signal: message transmitted by a DM-REP in order to indicate its presence on an RF carrier.
DM GATEway (DM-GATE): device which provides gateway connectivity between DM-MS(s) and the TETRA V+D network. The gateway provides the interface between TETRA DMO and TETRA V+D mode.
DM REPeater (DM-REP): device that operates in TETRA DMO and provides a repeater function to enable two or more DM-MSs to extend their coverage range. It may be either a type 1 DM-REP, capable of supporting only a single call on the air interface, or a type 2 DM-REP, capable of supporting two calls on the air interface. A type 1 DM-REP may operate on either a single RF carrier (type 1A DM-REP) or a pair of duplex-spaced RF carriers (type 1B DM-REP). A type 2 DM-REP operates on a pair of duplex-spaced RF carriers.