Digital Enhanced Cordless Telecommunications (DECT); Reference document

Updating of the general description of the DECT system and its principles

Digitalne izboljšane brezvrvične telekomunikacije (DECT) - Referenčni dokument

General Information

Status
Withdrawn
Withdrawal Date
30-Sep-2003
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
01-Oct-2003
Due Date
01-Oct-2003
Completion Date
01-Oct-2003
Mandate

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PSIST ETR 015:1998
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SLOVENSKI STANDARD
PSIST ETR 015:1998
01-november-1998
'LJLWDOQHL]EROMãDQHEUH]YUYLþQHWHOHNRPXQLNDFLMH '(&7 5HIHUHQþQLGRNXPHQW
Digital Enhanced Cordless Telecommunications (DECT); Reference document
Ta slovenski standard je istoveten z: ETR 015 Edition 1
ICS:
33.070.30 'LJLWDOQHL]EROMãDQH Digital Enhanced Cordless
EUH]YUYLþQHWHOHNRPXQLNDFLMH Telecommunications (DECT)
'(&7
PSIST ETR 015:1998 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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PSIST ETR 015:1998
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PSIST ETR 015:1998
ETSI ETR 015
TECHNICAL March 1991
REPORT
Source: ETSI TC-RES 3 Reference: DTR/RES-03001
ICS: 33.080, 33.060.20
Telephones, cordless telephony, digital radio systems
Key words:
Radio Equipment and Systems
Digital European Cordless Telecommunications (DECT)
Reference document
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
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
Tel.: +33 92 94 42 00 - Fax: +33 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 1991. All rights reserved.
New presentation - see History box
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PSIST ETR 015:1998
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ETR 015: March 1991

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 Editing and Committee Support Dept." at the address shown on the title page.

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PSIST ETR 015:1998
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ETR 015: March 1991
Contents

Foreword...........................................................................................................................................5

1 Introduction...............................................................................................................................7

1.1 The current situation....................................................................................................7

1.2 What is DECT ?..........................................................................................................7

1.2.1 Basic characteristics.................................................................................7

1.2.2 DECT Systems ........................................................................................7

1.2.3 Benefits of DECT .....................................................................................8

2 Services definition .....................................................................................................................8

2.1 Introduction.................................................................................................................8

2.2 Areas of application: user group...................................................................................8

2.3 Service principles ........................................................................................................9

2.4 Capability and features................................................................................................9

2.4.1 Residential use.......................................................................................10

2.4.1.1 Basic capability ..............................................................10

2.4.1.2 Enhancement features ....................................................10

2.4.2 Public use..............................................................................................10

2.4.2.1 Basic capability ..............................................................10

2.4.2.2 Features depending on infrastructure enhancements .........10

2.4.3 Small (business) system use ...................................................................10

2.4.3.1 Basic capability ..............................................................10

2.4.3.2 Features depending on infrastructure enhancements .........10

2.4.4 Large (business) system use...................................................................11

2.4.4.1 Capability.......................................................................11

2.4.5 Non-voice services for DECT...................................................................11

2.4.5.1 Applications....................................................................11

2.4.5.2 Teleservices...................................................................12

2.4.5.3 Bearer services.............................................................. 12

2.4.5.4 Spectrum efficiency ........................................................12

2.4.5.5 Error ratios ....................................................................12

2.4.5.6 Asymmetry.....................................................................12

2.4.5.7 System requirements......................................................13

2.4.6 Evolutionary applications.........................................................................13

2.4.6.1 DECT extension to cellular radio ......................................13

2.4.6.2 Radio extension of the local public network.......................13
2.4.6.3 Distributed DECT head-ends ...........................................13

2.5 Grade of service.......................................................................................................13

2.5.1 Large (business) system use...................................................................14

2.5.2 Residential and small (business) system use ............................................14

2.5.3 Public use (telepoint) ..............................................................................14

2.5.4 Non-voice services .................................................................................14

2.6 Performance requirements.........................................................................................14

2.6.1 Residential busy-hour traffic density.........................................................14

2.6.2 Business cordless telecommunication systems busy-hour traffic density .....15

2.6.3 Telepoint ...............................................................................................15

2.7 Authentication and security.........................................................................................15

3 Radio aspects.........................................................................................................................16

3.1 Principles of DECT radio usage..................................................................................16

3.1.1 Introduction............................................................................................16

3.1.2 Differences to standard ISDN..................................................................17

3.1.3 Scope ...................................................................................................17

3.2 The layered structure on the radio link ........................................................................18

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3.2.1 Overview ...............................................................................................18

3.2.2 Physical Layer (PHL) .............................................................................19

3.2.3 Medium Access Control layer (MAC) .......................................................20

3.2.6 Management Entity (MGE).....................................................................21

3.3 Capacity management in DECT..................................................................................22

3.3.1 Introduction............................................................................................22

3.3.2 The concept of the basic DECT base station ............................................22

3.3.3 The Dynamic Channel Selection (DCS).....................................................22

3.3.4 Call set-up using base station beacon channels.........................................23

3.3.5 Handover...............................................................................................23

3.4 Radio resource .........................................................................................................23

3.4.1 Spectrum requirements...........................................................................23

3.4.2 The allocated frequency band..................................................................24

3.4.3 Evolution of spectrum usage....................................................................24

4 Networks structure - network aspects of DECT .........................................................................25

4.1 Introduction...............................................................................................................25

4.2 Architectural aspects.................................................................................................25

4.3 Control and user elements .........................................................................................27

4.4 Protocol features.......................................................................................................28

4.4.1 The data link protocol .............................................................................30

4.4.2 Network layer protocol............................................................................30

4.5 Speech compatibility..................................................................................................32

5 Time scale..............................................................................................................................32

5.1 Achievements............................................................................................................32

5.2 Timescale.................................................................................................................33

5.3 List of deliverable documents .....................................................................................33

6 DECT terminology ...................................................................................................................34

6.1 Scope ......................................................................................................................34

6.2 Definitions.................................................................................................................34

6.3 Glossary...................................................................................................................43

6.4 Acknowledgement.....................................................................................................46

History .............................................................................................................................................47

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ETR 015: March 1991
Foreword

ETSI Technical Reports (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

application of ETSs or I-ETSs, or which is immature and not yet suitable for formal adoption as an ETS or

I-ETS.

This ETR has been produced by the Technical Committee RES, Radio Equipment and Systems, Sub-

Technical Committee 3 (in charge of DECT) of the European Telecommunications Standards Institute

(ETSI).

The present document aims to provide an overall description of the DECT system and concept, DECT

standing for Digital European Cordless Telecommunications.
DECT : Digital European Cordless Telecommunications;
ETSI : European Telecommunications Standards Institute;

RES3 : ETSI Radio Equipment and Systems, Sub-Technical Committee 3, (in charge of DECT);

CEPT : Conférence Européenne des Postes et Télécommunications.
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Blank page
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1 Introduction

At the present time there are a number of incompatible cordless telephone systems within Europe. These

systems fulfil only a proportion of the requirements and opportunities for personal communication

expectations.

The presence of the current systems has itself encouraged an extension of the concept and expectations

for cordless communication. Market research has established a clear demand for cordless capabilities

beyond those currently offered.

The greatest opportunity for European telecommunications organisations lies in offering a single standard

enhanced cordless system for Europe. The size of the European market and the capacity of the European

manufacturing base indicates that the fulfillment of the European need will create a spring-board for

opportunities outside Europe.

Only a common standard defined by industry, PTTs, and Administrations under the auspices of the

European Telecommunications Standards Institute (ETSI) can open up the European market to its full

potential.
1.1 The current situation

The extent to which the market is divided can be seen from a review of current products :

- Illegally imported Cordless Telephones;

- National specifications, working generally in one country (UK, France), using low frequencies under

50 MHz;

- CEPT analogue products (CT 1) working around 900 MHz, adopted only by some countries;

- A digital (FDMA) system, developed in the UK, offering the telepoint function as a feature. CT2/CAI;

- A digital (TDMA) system, developed in Sweden and emphasizing business cordless telephony. CT3.

A common European standard will remove the restriction and enhance market opportunities.

This common European standard will be DECT.
1.2 What is DECT ?
1.2.1 Basic characteristics

The DECT concept is one of versatility of application at a cost that encourages wide availability and market

adoption.

The concept includes a definition of personal portable communications that requires small, easy to use

terminals.

DECT will provide personal communication services at home, in the office and in the street.

The quality of communications is similar to that of a standard telephone.

DECT offers low-power cordless access between portables and infrastructure, at ranges up to several

hundred meters. It is utilising dynamic channel selection from approximately 120 available channels.

1.2.2 DECT Systems

- A DECT residential system that interconnects to a PSTN with the features and responses of a

standard wired telephone;
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- A DECT Business Cordless Telecommunications systems (BCT) that combines the features of a

PBX with the mobility of cordless telecommunications for both voice and non-voice applications;

- A DECT telepoint facility that offers public network access to a handset through a public, or privately

owned, base station;

- A DECT access system that provides a radio means of extending public and private networks into

customer/user premises.
1.2.3 Benefits of DECT

- Versatile application based on a common technology provides an economy of scale that will yield

low cost and encourage a wide take-up.

- DECT will allow full cordless application in an average office environment (typically in one hundred

times the density of a mobile radio system);

- The user has the opportunity to select from a number of communication options, to suit his particular

requirements;

- The manufacturer has the option to provide competitively targeted product according to his own

market perceptions;

- The network provider (public and private) has the opportunity to introduce new services and provide

alternative means of network access;

- National communication authorities have the opportunity to encourage competitive service provision

in new areas;
- DECT allows the use of private "on site" user applications.
2 Services definition
2.1 Introduction

In this section the service and facility requirements of envisaged cordless-telecommunication applications

are considered. The approach adopted is to identify application areas, define basic service principles,

determine functional capability requirements, and quantify performance parameters. Approaching the

problem of definition from a user-group point of view avoids the difficult task of identifying and defining

particular applications, especially applications associated with so called large business systems.

2.2 Areas of application: user group
- Residential - private use in houses and apartment blocks;
- Public Access - telepoint, phonepoint access to a PSTN;
- Small (business) CT systems - typically key systems;

- Large (business) CT systems - multi-cell PBX-based building mobile system with roaming and

handover;

- Integrated services premises networks, small and large (business) applications - voice and data

telephony and LAN access;
- Evolutionary applications - radio access to local public and other networks.
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2.3 Service principles

- The technical system specification makes provision for both voice and non-voice transmission;

- The DECT timescale coincides with the introduction of ISDN services. The implementation of all

ISDN basic rate services will be possible within the DECT specification;

- To provide the facilities and quality of service to key markets DECT minimises its use of bandwidth

to that required by the service carried at any time;

- The DECT specification does not inherently pre-allocate spectrum by application and should seek to

offer an integrated communication structure embracing all applications;

- The cost of implementing basic voice only operation must not be significantly penalised by the

non-voice provisions in the specification;

- The potential total market for DECT is large with the consequent requirement for low-cost,

small-size, high volume products, used in high-capacity applications;

- The technical system specification makes provision for interoperability of a handset unit between

user groups. Interoperability is not mandatory;

NOTE: The intention is not to preclude interoperability or hamper single user group

applications.

- The user perception of the combination of quality and value of communication of DECT apparatus

must be at least equal to that offered by existing wired telephone services noting there are two

parties to communication.
2.4 Capability and features

Capability and features are aligned according to area of application (market segment) rather than product

type. It is recognised that widely differing products could serve the same market segment, or a

combination of market segments.

The technical system specification makes provision for both basic capabilities and enhancement features.

Some capabilities and features are common to the four prime areas of application (residential, public, small

system and large system) and for convenience are listed as follows.
Basic capability

- Function as an equivalent replacement for a wired telephone connected directly to indirectly (e.g. via

PABX) to a PSTN;
- Signalling capacity to support standard telephony features;
- Dialling and calling security;
- Emergency services.
Enhancement features
- Interface with ISDN;

- Non-voice transmission, with ability to communicate up to maximum available transmission capacity;

- Air-interface voice, and non-voice, privacy;
- Hands-free operation;
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PSIST ETR 015:1998
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- Handsets serving a combination of market segments or services.
2.4.1 Residential use
2.4.1.1 Basic capability
- Base-station ringer.
2.4.1.2 Enhancement features
- 2 PSTN lines;
- 2 to 4 handsets;
- Intercom via the base station;
- Call transfer between handsets.
2.4.2 Public use
2.4.2.1 Basic capability
- Out-going calls only;
- Secure authentication of handset and user for billing;
- User indication of service availability on handset;
- Multiple independent network operation;

- Tandem use with other mobile systems, appropriate to car, train, plane and ship.

2.4.2.2 Features depending on infrastructure enhancements
- In-coming call (local log-on);
- In-call hand-over to adjacent telepoint base-station;
- Outgoing calls queuing capability for access to radio interface.
2.4.3 Small (business) system use
2.4.3.1 Basic capability
- Single cell;
- 20 extensions or less;
- Handset inaccessible indication at base unit;
- Secure authentication of handset.
2.4.3.2 Features depending on infrastructure enhancements
- Secure validation of handset user;

- Independent small (business) systems can be interconnected (by wire) to achieve coverage

expansion without handover;
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PSIST ETR 015:1998
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- Handsets can enrol on other units;
- Message (acknowledged paging) service.
2.4.4 Large (business) system use

No realistic judgement could be made between basic and enhancement features. It is considered essential

the specified system should support the following.
2.4.4.1 Capability
- Multi-cell operation;

- Roaming (to find a person for incoming and outgoing calls within the nominated communication

area);
- Handover during call;
- Normal (wired) PBX functions must be supported;
- Bearer services (to be expanded);
- Teleservices (e.g. teletext and fax);
- Handset or terminal enrolment;
- Support for systems of highly variable user densities;
- Terminals mounted in a vehicle (e.g. warehouse vehicles).
2.4.5 Non-voice services for DECT

The development of DECT will coincide with the establishment of ISDN networks and the widespread use

of integrated services voice/data networks in the office. It is therefore essential that DECT can support an

adequate range of non-voice services, to prevent it becoming obsolete before its introduction.

2.4.5.1 Applications
The applications of DECT data terminals fall into two categories:

- Primarily static, using DECT as a cordless drop-line bearer to a high-speed back-bone. Application

areas and requirements are related to those anticipated for general network terminal usage;

- Primarily portable, for entirely new applications made possible by the DECT network link such as:

- portable multi-media (e.g. voice and fax) mail terminal;
- note-pad with large network-based memory;
- portable access to personal and corporate data bases;
- ultra-light, small network-slaved PC emulator;
- cordless ISD videophone.
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2.4.5.2 Teleservices

From a service and facilities perspective, applications such as these examples require the support of a

group of general teleservices. These are:
- remote terminal service;
- batch file transfer;
- real-time file access;
- generic ISDN connection-based services.

Applications such as videophone can be successfully mapped on to the last category. To support the other

teleservices, DECT must have, as a minimum requirement, appropriate bearer capabilities over which

external processes can offer the teleservices. The integration of the teleservice processes in DECT

depends upon the implementer. Remote terminal protocols such as X and OSI VT, batch file services such

as FT AM and real-time access for X.400 protocols P3 and P7 will be examples to be supported.

2.4.5.3 Bearer services

In order to use the spectrum efficiently, DECT must offer bearers which are well matched to the needs of

the teleservices. A (2B + D) so bearer (net 144 kb/s connection-based full duplex) are necessary to meet

the needs of the generic ISDN connection-based services, but it is neither efficient nor adequate for the

other teleservices. The requirements of the other teleservices are summarised in the table below:

�˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¿
‡ Application ‡ Link Establishment ‡ Transaction Duration ‡ Full Rate ‡
‡ ‡ Time ‡ at Full Rate ‡ ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡ Remote Term ‡ ‡ ‡ ‡
‡ - text ‡ 50 ms ‡ 100 ms - 5 secs ‡ 10 - 20 kb/s ‡
‡ - graphics ‡ 50 ms ‡ 500 ms - 10 secs ‡ 24 - 128 kb/s ‡
‡ ‡ ‡ ‡ ‡
‡ Batch File ‡ ‡ ‡ ‡
‡ Transfer ‡ ‡ ‡ ‡
‡ - light ‡ 1 - 5 secs ‡ 1 - 30 secs ‡ 32 kb/s ‡
‡ - heavy ‡ 1 - 30 secs ‡ 5 - 1000 secs ‡ 64 kb/s ‡
‡ ‡ ‡ ‡ ‡
‡ Real-time ‡ ‡ ‡ ‡
‡ file access ‡ ‡ ‡ ‡
‡ - slices ‡ 50 ms ‡ 200 ms - 2 secs ‡ 64 - 256 kb/s ‡
‡ - chunks ‡ 500 ms ‡ 1 - 10 secs ‡ 64 - 256 kb/s ‡
�˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜�
2.4.5.4 Spectrum efficiency

Provided the link establishment time requirements are met, the long-term channel usages of these are

typically of the order of 0.01 - 0.1 erlangs. These will be translated into spectrum occupancy of 1 erlang,

however, if the radio channel access technique cannot meet the link establishment time requirements and

thus continuously open channels are required.
2.4.5.5 Error ratios

A characteristic of non-voice services is the high-quality logical channel they require. Net bit-error ratios of

10 are the minimum acceptable. These may of course be accomplished by use of FEC and ARQ at

layers 1-4, but carry an overhead in the physical layer.
2.4.5.6 Asymmetry

Since non-voice services often involve a flow of information which is predominantly in one direction,

unidirectional or asymmetric bearers can offer more efficient performance. Greatest efficiency can be

achieved if the bearer dynamically adjusts its forward/return ratio to the data requirements. Should this be

impractical, a mode with 10 : 1 forward/return ratio is required.
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2.4.5.7 System requirements

The need to use spectrum efficiently and at the same time offer an acceptable standard of non-voice

performance, therefore impose certain fundamental requirements on the system. These are listed in order

of importance:

- a radio resource assignment system capable of allocating different amounts of bandwidth to a

channel of the time the channel is established;

- a radio resource assignment system capable of allocating bandwidth between up and down link

independently.

Other issues, such as error correction, can be dealt with either at layers 1, 2, or 3 within DECT, or layer 4

of the teleservices function, and thus need further detailed consideration.
2.4.6 Evolutionary applications
2.4.6.1 DECT extension to cellular radio

Clear need is seen for DECT extensions to cellular radio systems to meet the requirements of:

- telepoint in a mobile environment, for example trains;

- to provide portable cordless access to mobile communications (including the GSM) particular in

areas where hand portable cellular transceivers are inadequately served.
2.4.6.2 Radio extension of the local public network

This application envisages the use of DECT as the access medium from the distribution point to the

customer premises, within the normal DECT coverage capabilities.
2.4.6.3 Distributed DECT head-ends

The DECT system is the basis for a range of business and telepoint-like services. It is expected that the

combination of cheaper digital transmission (fibre) and a larger private switches will lead to situations

where the radio part of the DECT will be distributed but the base-band processes, channel control and

signalling will be centralised. DECT with a 7 to 10 year life-span must accommodate such developments.

Investigation of the necessary range has indicated the following:

- In the USA the distance between a private central switch (centrex) and customer building is

generally cable-quality limited (copper cables) to typically 12,000 feet (3,8 km);

- Currently equivalent UK plans envisage using local exchanges as the central location, which indicates

a services range up to 5 km.

- A telepoint system with the remote transmitters and receivers would require also a 5 km range;

- For application of DECT in a suburban local-network cordless-access mode, range from a residence

to an appropriate network concentration point would be 5 - 7 km.

It would seem therefore that DECT should accommodate a transmission range between the DECT control

centre and radio head-end of 5 km.
2.5 Grade of service

In terms of user acceptability of such proposals it is essential that cordless connections should closely

match wire-connected terminals from a grade-of-service (GOS) point of view. In this report GOS is

equated to the overall probability of a call not being set-
...

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