Mitel SIP-DECT Site Survey Kit User manual

SIP-DECT Site Survey Kit
USER GUIDE

NOTICE
The information contained in this document is believed to be accurate in all respects but is not
warranted by Mitel Networks™ Corporation (MITEL®). The information is subject to change without
notice and should not be construed in any way as a commitment by Mitel or any of its affiliates or
subsidiaries. Mitel and its affiliates and subsidiaries assume no responsibility for any errors or
omissions in this document. Revisions of this document or new editions of it may be issued to
incorporate such changes.
No part of this document can be reproduced or transmitted in any form or by any means - electronic
or mechanical - for any purpose without written permission from Mitel Networks Corporation.
Trademarks
Mitel is a trademark of Mitel Networks Corporation.
Windows is a trademark of Microsoft Corporation.
Other product names mentioned in this document may be trademarks of their respective companies
and are hereby acknowledged.
SIP-DECT Site Survey Kit User Guide
July 2015
®,™ Trademark of Mitel Networks Corporation
© Copyright 2015, Mitel Networks Corporation
All rights reserved

Table of Contents
iii
USING THE SIP-DECT SITE SURVEY KIT
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Exclusion of Liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The SIP-DECT Site Survey Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SIP-DECT Site Survey Kit Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
DECT Base Station Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Setting up the Mitel 650 DECT Phone for Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Preparing for the Next Measurement Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Charging the Powerpack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Charging the Mitel 650 DECT Phone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Charging the iPod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Display and Softkeys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Measurements in Active Call State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Audio Quality Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Handover Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Planning and Site Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Ascertaining Customer Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Initial Determination of Base Station Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Optimum Positioning of the DECT Base Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
DECT Base Station for Outdoor Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
DECT Base Station for Indoor Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Preparing the Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Handover Overlap Areas: Base Station Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Traffic Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Hotspots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Measuring Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
TDM-Base Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
IP-Base Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Initial Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Coverage Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Coverage of a Radio System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Radio Characteristic of a Base Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
High-Frequency Propagation Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

SIP-DECT Site Survey Kit User Guide
iv
Interference Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Reception Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Using External Antennas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Fading Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
APPENDIX A: TECHNICAL DATA
Technical specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

USING THE SIP-DECT SITE
SURVEY KIT

SIP-DECT Site Survey Kit User Guide
2

Safety Information
3
SAFETY INFORMATION
Failure to observe this information can be hazardous and infringe existing laws. Please read this
document before starting the testing and keep it for future reference. Make sure you always
include the Manual when handing over the test kit to third parties.
• Do not use the test kit in areas subject to explosion hazards.
• Important information on using the batteries can be found in the Appendix.
• Do not place the equipment
- near sources of heat
- in direct sunlight
- near other electrical equipment
• Protect the equipment from the wet, dust, corrosive liquids and steam.
• Only connect approved accessories.
• Research has shown that in some cases, medical equipment can be affected by portable
phones (DECT phones) when activated. Always observe the rules and regulations of the
establishment concerned when using portable phones within medical facilities.
• Never
- open the equipment itself!
- touch the plug-in contacts with sharp and/or metallic objects!
• Only use a slightly damp cloth to clean the equipment.
EXCLUSION OF LIABILITY
• This product is manufactured in accordance with ISO 9001 quality criteria.
• This product and the user information supplied with it have been produced with the utmost
care.Theproduct'sfunctionshavebeentestedandapprovedaftercomprehensiveconformity
tests. Nonetheless errors cannot be entirely excluded. The warranty is limited to the
replacement of defective hardware.
• The manufacturers shall not be liable for direct or indirect damage that may be caused by
incorrect handling, improper use, or any other faulty behaviour on the part of a product.
Liability for loss of profit shall be excluded in any case.

SIP-DECT Site Survey Kit User Guide
4
THE SIP-DECT SITE SURVEY KIT
SIP-DECT SITE SURVEY KIT CONTENTS
SIP-DECT Site Survey Kit - Upper Layer
SIP-DECT Site Survey Kit - Lower Layer
The Tripod bag includes the tripod (light stand) with Powerpack bracket and DECT base station
mounting plate.

Setup
5
SETUP
In preparation for the measurement session and to optimize battery life time, all components
should be fully charged. The Powerpack, Mitel 650 DECT phone and iPod should be switched
off before being stored in the carrying case and for longer breaks between measurement
sessions.
DECT BASE STATION SET UP
Setting up the RFP SI (with internal antennas)
1. Install the tripod (light stand).
2. Attach the Powerpack in bracket.
3. Connect the PoE cable to the Powerpack (use the standard
RJ45 connector).
4. Screw the DECT base station mounting plate on the tripod.
5. Attach RFP SI (with Status-LED’s 1-2-3-4 bottom-up).
6. Connect the PoE cable to the DECT base station via the RJ45
field plug.
7. Switch the Powerpack ON.
• Short press on button with a pin turns the Powerpack ON (RJ45 LED
is green)
• Long press on button turns the Powerpack OFF (RJ45 LED is off)
8. Wait for the DECT base station (RFP SI) to come up.
LED state (bottom-up): 1+2 alternate green/orange, 3= green if DECT-ready, 4=off (only for
WLAN).

SIP-DECT Site Survey Kit User Guide
6
Additional setup for RFP SX (with external antennas)
SETTING UP THE MITEL 650 DECT PHONE FOR MEASUREMENT
1. Switch ON the Mitel 650c DECT phone for measurement.
2. Date/Time Edit or Esc.
3. Wait until subscribe.
1. Connect the mounting kit for external
antennas on top.
2. Install the antennas (“dipole antennas” or
"directional antennas with BNC connector“).
3. Connect the antenna cables to the DECT
base station.
The DECT phone shows the standard measurement mode
display with RFP Number (RPN:) and field strength (dBm:).
Troubleshooting during Startup
The Mitel 650c starts up in non-standard measurement mode
(e.g. due to switch off in other mode).
Switch back to the standard measurement mode via:
Right side key (Service menu).
The right side key is not programmed with "Service menu“. The
wrong menu structure may activated by accident.
Set up the correct menu structure via:
Menu -> Settings -> Display -> Menu Structure -> [PIN].

Setup
7
PREPARING FOR THE NEXT MEASUREMENT SESSION
Inpreparationforthenextmeasurementsessionandtooptimizebatterylifetime,allcomponents
should be fully charged. The Powerpack, Mitel 650 DECT phone and iPod should be switched
off before being packed into the carrying case.
CHARGING THE POWERPACK
CHARGING THE MITEL 650 DECT PHONE
• Charge the Mitel 650c in the charger.
• Wait until the Mitel 650c is fully charged.
• Ensure that the Mitel 650c is switched off before placing it in the carrying case.
CHARGING THE IPOD
• The iPod can be charged with the Lightning-USB cable as described in the Quick Guide.
• Ensure that the iPod is switched off before placing it in the carrying case.
• Charge the Powerpack only with the Ansmann ACS 310.
• Notice the LEDs on the charger.
• Wait until the Powerpack is fully charged (may need up to
6 hours).
• Ensure that the Powrpack is switched off before placing it in
the carrying case.

SIP-DECT Site Survey Kit User Guide
8
MEASUREMENTS
For accurate results, all measurements must be made in active call state. A connection between
the two DECT phones is established. The audio quality measurements support the site survey.
By default, the DECT phones are subscribed to both RFP SI and RFP SX (DECT base stations)
from the SIP-DECT Site Survey Kit. The DECT base stations are single cell with different PARK
codes. Handover between RFP SI and SX is not possible.
DISPLAY AND SOFTKEYS
Standard display in idle state
XQ mode
ThiskeytogglestheXQtoOFF/ON.DefaultisONandXQiscontrolledbytheDECTbasestatoin.
DECT measure mode
All visible DECT base stations from subscribed networks and from alien DECT networks are
shown in a list.
Audio mode
Select between Standard Audio, Hi-Q audio, and Automatic mode.
Nr
dBm
RFPI
Stop
Start
Clear
ESC
= item number (ordered from high to low, by field strength)
= field strength
= Radio Fixed Part Identifier (DECT base station identifier)
= stops measurement, freezes screen, enables scrolling
through a longer list
= starts measurement again
= clears screen for new measurement
= quits DECT measure mode, returns to default

Measurements
9
Service Menu
The Service menu (accessed from the right side key) allows changing several measurement
defaults.
MEASUREMENTS IN ACTIVE CALL STATE
By default, the measurement DECT phones are subscribed to the site kit DECT base stations
with phone numbers 50 and 60. These numbers are initially programmed reverse as quick dial
to “2”. This can be changed manually.
In an active call between the measurement DECT phones, you see the following:
Site survey On/Off
DECT XQ-mode On/Off
Automatic handover On/Off
Line in On/Off (default Off = headset mode, On = iPod
mode)
Actvitates DECT Measure Mode
Audio mode
System subscriptions
Key programming and Reset to default values
Hi-Q wideband audio connection
Encryption active
RFPI= Radio Fixed Part Identifier
sN/cN = slot number / carrier number; FE = frame errors on handset
(P:) RFP (F:)
RPN = Radio Fixed Part Number
dBm = field strength
Long slot, G.722 Codec used

SIP-DECT Site Survey Kit User Guide
10
AUDIO QUALITY MEASUREMENTS
You can verify audio quality between the two Mitel 650c measuring DECT phones.
The DECT phone acting as audio source is fixed toa location with good field strength. The other
DECT phone can be used with an external headset to check the audio quality at a distant site.
1. Define the first Mitel 650c as audio source.
2. Toggle “Line in / ON” in the Service menu.
3. Connect the music player (iPod) via the audio cable.
4. Toggle “Line in / OFF” in the service menu of the second Mitel 650c (you can use an external
headset to check the audio).
5. Make a call between the DECT phones.
6. Start the audio stream on the iPod (FM radio or mp3).
7. Use the second Mitel 650c to hear the audio stream.
8. Verify the audio quality while walking in the measuring area.
Standard narrowband audio connection
Full slot, G.726 Codec used

Measurements
11
HANDOVER MENU
The Handover menu enables an additional measurement mode to verify handover for deployed
DECT installations with several base stations. Not applicable for the first measurements made
with the SIP-DECT Site Survey Kit.
Handover menu in active call state
Initiate “Handover to: *” by a long press on the star (*) key (only in call).
Toggle automatic handover On/Off function by a long press on the hash (#) key.
After the DECT phone is turned OFF/ON, automatic handover is always active.
Display RFPs (will not be updated)
Handover to * (best rssi)
Handover to 1
Handover to 2
Handover to 3
Automatic handover On/Off
Success Failure

SIP-DECT Site Survey Kit User Guide
12
PLANNING AND SITE SURVEY
The planing procedure is described below.
1. Ascertain customer requirements.
2. Roughly determine the locations for the base stations.
3. Measure out the DECT system on site.
4. Install and re-measure the system.
ASCERTAINING CUSTOMER REQUIREMENTS
Since the aim of DECT systems is to cover all kinds of different mobility requirements in a
non-standardized environment, you need to determine and record precisely what sort of
requirements the customer has in mind. Records avoid misunderstandings and can be used as
aworkingpaper(e.g.projectprogressreport)orasspecificationstobeconfirmedbythecustomer.
Important questions:
• Situation: Where are the calls to be made from – outdoors/indoors?
• Premises: What surface area and what height or depth (stores, basement floors) form part
of the supply range? Recommendation: Request building plan or make a sketch.
• Building structure: What sort of materials and types of construction are the buildings made
of? What sort of structural changes are planned for the near future?
• Subscribers: How many DECT phones are required? What sort of calling patterns do users
have?
• Traffic density: How are the DECT phones distributed throughout the premises and which
users are where? (Specify areas with a high traffic density.)
• Dynamics: How many DECT phones are expected where and at what times of the day?
Recommendation: Take account of special infrastructure areas such as cafeteria
9:00…10:00, meeting rooms, open-plan office.
INITIAL DETERMINATION OF BASE STATION LOCATIONS
Radio circumstances are difficult to estimate. For this reason, situations regarded as particularly
critical need to be determined on site through measurements.
This will provide a reliable idea of theequipment requiredand the locationsfor thebase stations.
The following rules of thumb may be of help:
• Goodconnectionsarestillpossible inahorizontaldirectionbehindtwoorthree ordinarybrick
walls; but there is barely any penetration through concrete floors and ceilings in a vertical
directionandingroundfloororbasementfloors(i.e.,eachstoremustbesuppliedseparately).
Acertainamountofverticalpenetrationcanbeexpectedfromthefirstfloorupwards;generally
speaking, radio propagation conditions improve as the distance from the ground increases.
• Openings in obstacles improve radio conditions.
• Subsequent furnishing: In empty buildings, the effect of the absence of furniture, machines,
partitions, etc., and their room limitation must be taken into account. Subsequent extensions
and conversions also have a considerable influence.

Planning and Site Survey
13
• It is important to ensure sufficiently large overlap areas between neighbouring coverage
ranges. The signal should not be so weak that it prevents handover to the next base station.
It is necessary to find a solution between a large number of radio units and a reasonable
coverage of the premises.
• Radio range (guidelines)
- up to 30 m in buildings
- up to 300 m outdoors
• Observe the minimum distance between base stations.
As soon as the concrete locations for the base stations have been planned, it is recommended
to confirm the circumstances in keeping with the plan using on-site measurements.
Notes
• Installation site for the test base station: To carry out the measurements, do not place the
basestationon theground/floorbut positionitinthe locationin whichitisto beinstalledlater.
• Measurementsmustbemeticulouslycarriedout(nocompromises).Theobjectiveisoptimum
radio coverage.
• Documentation: It is advisable to keep a test log so results can be reproduced later.
• Record the values measured as well as the supply range on the ground plan, horizontal and
vertical.
• The measurements provide a reliable idea of the equipment required and the locations for
the base stations.
• Co-operation with the customer: As soon as you are able to make sufficiently binding
statementsabout"problemareas",youshouldinvolvethecustomerforclarificationpurposes.
It is imperative that the customer be informed of any areas where coverage is not optimum.
OPTIMUM POSITIONING OF THE DECT BASE STATION
The location of the DECT base station is determined by several factors:
• Optimum radio coverage of the environment
• Conditions inside the building
• Installation possibilities
• Presence of supply leads and socket outlets
• Aesthetic aspects and wishes on the part of the customer
• Outside the buildings: weather protection (rain, sun), vandal-proof
Notes
Please note that base stations must be spaced out at intervals of approx. 2.50 m horizontally
and 1 m vertically. An ideal location for installing a transmitter is a height of between 2 m and
2.50 m (for room heights between 2.50 and 3 m; for higher rooms, the ideal installation height
increases accordingly) while maintaining a minimum distance of 0.50 m from the ceiling. An
installation height of less than 1.50 m is not recommended.
Installationinside adroppedceiling, cabinets orotherenclosedfurnishingsisnot recommended,
as this impairs the radio hop considerably and results in the need for more transmitters.

SIP-DECT Site Survey Kit User Guide
14
If aesthetic considerations prevail, this must be compensated for with a greater number of base
stations, provided this is not rendered impossible by metallic ceiling structures.
Make sure the transmitters are fitted vertically and that the radiating surface is in keeping with
your measurements.
When installing transmitters with external directional antennas, make sure the two antennas
radiateinthesamedirection.Thedistancebetweenthe twoantennasshouldcorrespondatleast
to the wavelength (15.7 cm).
DECT BASE STATION FOR OUTDOOR SUPPLY
Observe the following principles when installing DECT base stations outdoors:
• Choose a central position and avoid flat penetration angles.
• Ensure that the selected location is as protected from the weather as possible and
corresponds to the type of protection of the outdoor base station.
• Make sure the installation site is at a sufficient height to be protected from acts of vandalism.
DECT BASE STATION FOR INDOOR SUPPLY
Observe the following principles when installing DECT base stations indoors:
• Install the base stations on inner walls rather than outdoor walls.
• Consider ceiling mounting, if appropriate.
• Do not install in the immediate vicinity of cable ducts, metal cabinets and other large metal
objects. They obstruct transmission and/or can result in crosstalk. Maintain a distance of
>50cm!
• Connecting line between PBX and DECT base station:
- Crosstalk can occur if the PBX and DECT base station are positioned in parallel with
mains feeder lines inside cableducts (e.g. engineering workshops). This must be taken
into account when choosing the cable and the cable route.
Note: When using directional antennas, make sure you maintain a safety distance of
0.5 m from any passers-by.
Tip: For outdoor supply always check the use of an external antenna, too. This may
result in a better solution, which can help to save costs in the long run.

Planning and Site Survey
15
- RF interference fields: PCs and other electronic equipment can affect radio
transmission in the vicinity either intermittently or permanently.
- Base stations and DECT phones generate pulsed RF signals. These can affect
sensitive electronic equipment (control systems, measuring sensors, sensors,
diagnostics equipment on intensive- care wards in hospitals, etc.) permanently or
temporarily.
PREPARING THE MEASUREMENTS
Drawing up a situation plan:
• The situation plan records approximately the number and size of the coverage ranges
required.
• The measurements provide the ideal locations for the base stations.
Radio coverage and area determination
• Make a note of the connection capacity required (number of simultaneous calls) for each
area to determine the number of base stations.
Global coverage in the supply range
• First, ensure that the surface area of the planned supply range is satisfactorily covered. The
ideal locations for the base stations are determined using practical measurements.
HANDOVER OVERLAP AREAS: BASE STATION SYNCHRONIZATION
TDM and IP-Base stations
• To guarantee a seamless handover, the base stations should be fitted in sucha way that the
-60dBm overlap area is guaranteed.
• When conducting survey measurements in unfinished buildings, the limits should be
increased by 10dB.
IP-Base stations (sync over air)
• To guarantee synchronisation, you need to arrange the base stations of a cluster in such a
way that there is at least one other base station within the -70 dBm limit! Aim to achieve an
overlap with other base stations (fail-safe setup).
TRAFFIC DENSITY
Once the supply range has been located and covered, the locations for the base stations are
known. In the second phase, you must consider other requirements: traffic volume, determined
bythenumberofDECTphones;andthefrequencyanddurationofconnectionsinanareadefined
by the customer. In most cases, such an area does not match the coverage range of a base
station.
Note:Takenoteofsafetydistancesandsafetyregulations.Inareassubjecttoexplosion
hazards take note of the relevant rules and regulations.
Note: Cluster defines a group of RFPs which synchronise among themselves and
among which a handover is possible; Up to 256 cluster can be set up for each system.

SIP-DECT Site Survey Kit User Guide
16
For each area you must determine the number of base stations currently being used to supply
them.
It may be necessary to boost the coverage with additional base stations for under-served areas
(in accordance with the customer's requirements). To do so, refer back to the base station
locations that were determined for the area coverage. For instance, it is a good idea to place
additional base stations at the center of an area with higher traffic volume, even if those units
end up between two installed base stations.
To determine the traffic volume, we assume three typical ranges: "low", "medium", "high".
"High"meansthatapprox.50%ofallDECTphonesmakecallssimultaneously.Itisalsoimportant
tonotethatthevolumeoftrafficcanvaryconsiderablythroughouttheday.Thequestionisalways
whether or not to cover a traffic volume that may be higher only briefly in a particular area.
HOTSPOTS
A hotspot is an area with an above-average number of DECT phones. Such an area can be
covered with several base stations as the resources in the coverage range of neighbouring base
stations are cumulated. It is recommended to cover hotspots with several base stations as they
operate in ”Zero-Blind-Slot mode” and the calls can be spread out across 120 radio channels.
In practice, the interference from neighbouring channels in a hotspot without special measures
means that only approximately one quarter of the radio channels can be used simultaneously.
This means that approximately 30 simultaneous connections are possible, which require, for
example, four base stations. Thus, approximately 60 DECT phones can be used in a hotspot
with high traffic volume (simultaneous call connections of approximately 50% of the DECT
phone). It is essential to observe the minimum distances when installing the base stations.
If extensive interference occurs in a hotspot, or if more than 30 simultaneous connections are
required, check the following:
• Distribute the base stations that cover the hotspot spaciously around the hotspot. In doing
so, walls in particular can help attenuate the strong signals that the base stations mutually
interfere with each other.
• Check the possibility of a spherical arrangement of the base stations that cover the hotspot
through floors and ceilings.
• EnsurethatDECTphonesdonotsuddenlyseizethecallchannelsofthehotspotbasestations
that were previously provided by other base stations (when setting up a connection, DECT
phones always seize channels of the base station that delivers the strongest signal). It may
thereforeoccurthatmoving thehotspotbasestationstriggers achain reactionandthatother
base stations have to be repositioned.
MEASURING PROCEDURE
Specifying limit values in different coverage areas
There are different requirements for the areas to be covered (e.g. office, basement) based on
the quality or use of the areas. Accordingly different limit values can be used for the
measurements. Even within a partial system different quality requirements can be specified for
the various base stations.
Generally speaking, itcan be said that systems which measure out up to –60dBm provide good
quality. Formeasurementsup to–70dBm itis necessarytoverify andevaluatethe measurement