Best Practices for In-Building & Spot Coverage Solutions

NPTSC Meetings – June 2006Ontario, CA

Best Practices for In-Building & Spot Coverage Solutions

Kenneth Monro

Dekolink Americas, Inc.

[email protected]

936-582-7000

June 13, 2006

NPSTC Meeting

Ontario, CA

mailto:[email protected]


Objective of presentation

1. To share information about market activity relative to in-building wireless solutions

2. To review best practices employed when considering in-building systems

3. To understand hardware options in the process of selecting the right tool for the right job

4. To review technology which enables quality deployments


“Coverage Solutions”


Trends in In-building

• In-building deployments have dramatically grown in number and continue to do so

• Some governmental agencies are mandating coverage in certain public buildings

• “Rogue” (un-coordinated/un-approved) deployments are cause for great concern to all mobile network operators

• Public safety officials are feeling the need to address carrier network coverage from public safety perspective


In-Building Best Practices

• Site Survey/Audit• Spectrum analysis

and coordination• System Design and

Engineering• Installation and

Implementation• Record and

Catalogue site specifics


Site Survey/Audit

• In-building DAS– Number of users in building– Number of users of foreign networks– Density of walls, ceilings– Proximity of windows relative to BTS– Existing signal strength in building– Building Size– Complexity of in building environment


Examples of in-building systems

Small Buildings



Large Buildings



Simple Solutions



Complex Solutions


Spectrum Analysis and Coordination

• Whose signals are in spectrum of proposed amplifier system

• How will it effect their system• RFC coordinators provide list of LMR operators• FCC can provide list of licensees of other

spectrum• Prior notice of proposed system is the right thing

to do!• Today’s public safety systems with carriers

spectrum under consideration as well as LMR!


Donor Link-- No Interference

Public Safety RadioDonor Base Station

Repeater

Repeater Donor AntennaBeamwidth

Repeater CoverageArea

Nextel

PrivateSMR NetworkBase Station

If other SMR BTS’ are outside donor antenna beam, use band selectiveClass B OK as long as coverage provided is non-interfering


806 809 816 821 824

851 854 861 866 869

900NON-NEXTEL

NEXTEL

SOME NEXTEL

B / ILT VOLUNTEERS

PHASE 1

NEXTEL

806 809 816 821 824

851 854 861 866 869

900

PHASE 3 NEXTELPUBLICSAFETY

NEXTEL806 809 816 821 824

851 854 861 866 869

900

PHASE 2

PUBLIC SAFETY

Band selective solutions

• Systems should be field re-bandable• Systems should have oscillation prevention technology


Small Site Coverage

To/From

Cell SiteYagi Antenna

Mini-Repeater

Indoor Coverage

Antenna


Larger Buildings

Floor 2

Floor 1

Floor 3

Floor 4

Floor 5

Floor 6

5/8" or 7/8" coax

RF Tap + 2 Way Splitter

Antenna

To/FromCell Site

Off AirDirectional Antenna(Yagi)

RepeaterRepeater drives distributed antenna system (DAS) in larger areas

DAS distributes even coverage

Quality systems can self optimize gain and level


Public Safety RadioDonor Base Station

Repeater

Repeater Donor AntennaBeamwidth

Repeater CoverageArea

Nextel

PrivateSMR NetworkBase Station

If the BTS for other SMR services are within the donor antenna beam width, the uplink may cause interferenceChannel Selective Repeaters eliminate interference problems

Donor Link-- Interference


824806 809 816 821

NOISE AND INTERFERENCE

FILTER FILTER FILTER FILTER FILTER FILTER

ISOLATED SIGNAL • INTERFERENCE MITIGATED

DSP (Digital Signal Processing)

Filter Bank

BEFORE

AFTER

Channel Selective Solutions

Channel Selective technology can be used in spectrum challenged environments


FCC – High Power Outdoor Coverage Repeaters Must be Class A Should be able to be RE-BANDEDShould have Oscillation prevention technologyHigh Power (50W) is desirable to meet most coverage requirementsMust select only those channels that are licensed to you!Should be capable of remote configuration/re-configuration and alarming as a network elementShould use digital filter technology

Channel Selective Devices

Digital Channel Selective Repeater


Advantages of Digital Signal Processing

• Filter Sharpness – Extremely tight “skirts” for out of band rejection

• Flexibility and Programmability– No of channels

– Channel locations

– Channel width

– Delay and moderation of delay

– Interference rejection


> 50 dB

@50 kHz

Filter Sharpness

10 dB / Div

> 40 dB

@600 kHz

Digital technology creates significantly sharper filters compared to advanced SAW IF filtering

Digital Filter SAW Filter


Yellow Springs, OH

• Political Rally held in remote area

• Poor coverage due to ravine and surrounding hills

• Temporary coverage requirement

• Solved with Channel Selective repeater

• Additional users included State, County and FBI officials for mission critical communications


• Should be treated as outdoor solution

• Very “do-able” with Channel Selectivity

• Leaky coax or DAS

Tunnel Coverage


Installation and Implementation

•• Antenna SpacingAntenna Spacing•• Proper IsolationProper Isolation•• Proper gain/levelProper gain/level•• Ingress/EgressIngress/Egress•• Cable typesCable types•• Power systemsPower systems•• Lightening ProtectionLightening Protection•• Coax/FiberCoax/Fiber


System Design and Engineering

Hardware Selection Process– Repeaters/BDAs

• Inherent Characteristics: – Power– Gain– Noise levels

• Important Features: – High Q filters and Frequency Selectivity– Level/Gain control– Oscillation monitoring/elimination– Software controlled Tuning, Alarming, management



Hardware Selection-- Ancillaries

– Donor antennas with high directionality– Cable and Connectors with low loss/Noise– Lightening arrestors at ingress/egress



Donor site path– What is signal crossing on it’s way to BTS– What is signal reaching past BTS– Is the signal too strong for application?– Do I need channel selectivity?– How is the network effected by

deployment?


Installation and Implementation

Case Study: Tier 1 PCS operator, NYC

• Carrier’s customer improperly self installed system• Donor antenna and coverage antenna too close

resulting in not enough isolation• System Oscillated causing spurious emissions• One single RF carrier affected• 200 base stations interrupted• 250,000 calls dropped• Subset of calls were 911


Impacted Cell Sites

Blue dots = Existing Cell Sites Green Stars = Cells with CRSSIRCTI > 5000


Record and Catalog site specifics

• Tracking of assets– Product type, power, gain, noise level

• Sharing of data possible– Dekolink is assembling a Process for

spectrum owners and users of equipment to identify locations even when not licensed!

• Reduces possibility of interference and reduces time to mitigate interference


Thank you!

Kenneth MonroDekolink Americas, [email protected]

mailto:[email protected]

Documents

Best Practices for In-Building & Spot Coverage Solutions