Product manual

System description, DECT air interface

Technical Product Manual - DCT1800-GAP

TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C

6.1.4 DECT profiles

DECT profiles ensure interoperability between cordless phones and DECT systems of different

vendors. A profile is a chosen subset of the overall DECT Common Interface (CI) standard. The

following profiles have been defined by ETSI:

• Generic Access Profile (GAP)

• ISDN interworking profile

• GSM Interworking Profile (GIP)

• Data service profile

• RLL access profile (RAP)

• CTM Access Profile (CAP)

The Generic Access Profile (GAP) provides a speech service for cordless phones that can be used

in business, residential and public applications. GAP can be seen as the basic profile from which the

other profiles have been derived. GAP is the industry standard for basic speech service with mobility

management available on every cordless phone and DECT system providing a 3.1 kHz telephony

service.

The GSM Interworking Profile (GIP) is intended for public speech service using the GSM network and

its mobility functions. This profile is closely related to GAP, but uses GSM network identities.

6.2 How the DECT radio link operates

DECT operates according to the following principles:

• Pico-cellular

• Multiple Carrier (MC)

• Time Division Multiple Access (TDMA)

• Time Division Duplex (TDD)

• Dynamic Channel Selection (DCS)

• Antenna diversity

6.2.1 Pico-cellular

The space around a base station in which radio communication with a cordless phone is possible is

called a cell. The radius of such a cell strongly depends on the environment in which the base station

is installed. In DECT the radio transmission power is fixed to 250 mW peak. To cover a larger area,

more cells must be used. When compared to cellular systems, cells are rather small in DECT. For this

reason they are sometimes referred to as pico-cells.

Pico-cells enable reuse of channels within a short distance. This results in a significant increase in

the number of simultaneous calls that can be handled within the available frequency band. So, within

an area covered by a number of base stations, the same radio channels can be used by different base

stations at the same time. When cells overlap the same channels cannot be used since they interfere

with each other (see figure

21).

Low-power radio also results in lightweight cordless phones that can operate many hours before the

batteries need recharging.