Nominal RF Design Link Budget Maximum path loss Propagation model Typical site configuration Site radius Nominal RF Design (coverage) Coverage requirements Nominal site count Coverage site count • Transmit Power • Antenna configuration (type, height, azimuth) • Site type (sector, omni) Traffic requirements • Standard hexagon site layout • Friendly, candidate sites • Initial site survey inputs Traffic site count Traffic > Cov. Cov. > Traffic • Recalculate the site radius using the number of sites from the traffic requirement • Repeat the nominal RF design Traffic requirements
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Nominal RF Design
Link Budget
Maximum
path loss
Propagation
model
Typical site
configuration
Site radius
Nominal RF
Design
(coverage)
Coverage
requirements
Nominal site count
Coverage site
count
• Transmit Power
• Antenna configuration
(type, height, azimuth)
• Site type (sector, omni)
Traffic
requirements
• Standard hexagon site
layout
• Friendly, candidate sites
• Initial site survey inputs
Traffic site
count
Traffic > Cov.
Cov. > Traffic
• Recalculate the site
radius using the
number of sites from
the traffic requirement
• Repeat the nominal
RF design
Traffic requirements
Nominal RF Design
• Calculation of cell radius
• A typical cell radius is calculated for each clutter environment
• This cell radius is used as a guide for the site distance in the respective clutter environment
• The actual site distance could varies due to local terrain
• Inputs for the cell radius calculation :-
• Maximum pathloss (from the link budget)
• Typical site configuration (for each clutter environment)
• Propagation model
Nominal RF Design
• There are different level of nominal RF design :-
• Only using the cell radius/site distance calculated and placing ideal hexagon cell layout
• Using the combination of the calculated cell radius and the existing/friendly sites from the customer
The site distance also depends on the required capacity
•In most mobile network, the traffic density is highest within the CBD area and major routes/intersections
•The cell radius would need to be reduce in this area to meet the traffic requirements
•BASED ON THE SITE DISTANCE & THE COVERAGE REQUIREMENTS CELL COUNT BASED ON COVERAGE IS CALCULATED.
Nominal RF Design
• Cell count based on traffic is derived based on capacity inputs:- • Capacity requirements • GOS • Spectrum availability • Freq. Hopping techniques
• If the total sites for the traffic requirement is more than the sites required for coverage, the nominal RF design is repeated using the number of sites from the traffic requirement
• Recalculating the cell radius for the high traffic density areas
• The calculation steps are :- • Calculate the area to be covered per site • Calculate the maximum cell radius • Calculate the site distance
Site Realisation
• After completion of Nominal design based on cell count ( coverage & capacity requirements) , search rings for each cell site issued.
• Nominal design is done , with the existing network in place(existing BTS). Existing site location remain unchanged , azimuth , tilts as per the new design requirements.
• Based on the search ring form physical site survey is undertaken.
Site Realisation
Search Ring Form
• Site ID
• Site Name
• Latitude/Longitude
• Project name
• Issue Number and date
• Ground height
• Clutter environment
• Preliminary configuration
• Number of sector
• Azimuth
• Antenna type
• Antenna height
• Location Map & SR radius
• Search ring objective
• Approvals
Spheroid:
Coordinates: (GPS)
o ' ''N
o ' ''E
Site AGL (m): 30 Antenna Type: 65 deg Vertical polarised
• Site survey Forms for all suitable candidates for the search ring
• For each candidates :- • Location (latitude/longitude) • Location map showing the relative location of the candidates and
also the search ring • Candidate information (height, owner etc) • Photographs (360º set, rooftop, access, building) • Possible antenna orientations • Possible base station equipment location • Information for any existing antennas • Planning reports/comments (restrictions, possibilities of approval
etc.)
Site Realisation-Site Survey Form
• Final RF Configuration Form
• Base Station configuration • Azimuth • Antenna height • Antenna type • Down tilt • Antenna location • Feeder type and length • BTS type • Transmit power • Transceiver
configuration
Date
BSNL Circle
CITY / SSA
Site ID
Site Name
Owner Name
Address & Contact No.
Construction
Tower Type Bldg. Hgt
Tower Hgt Antenna Ht
Coordinate LAT N LONG E
GSM ANTENNA :
AZ M-TILT
SECTOR 1 85° +1.9 Spheroid:
SECTOR 2 185° +0.7
SECTOR 3 307° +1.3
Candidate No.
Assess: Priority
Morphology/Clutter
Site Blockage if Any
Remark
Name: Name:
Signature: Signature:
BSNL/ NBSNL
20 m.
GBT / Rooftop 10 m.
6 m.
AP909014-2
BSNL Survey Team Representative Nokia Representative
Accept/ Reject
TECHNICAL SITE SURVEY FORM
June 12, 2004
BHPAT-09
Bihar
AP909014-2
AP909014-2
Patna 09
Container/Room
85° 48 ' 31.2"26° 21' 25.9"
TYPE
Traffic Engineering
Spectrum
Available Reuse factor
Maximum number
of TRX per cell
No of TCH
available Traffic offered
Traffic
Requirement
Subscriber supported
Channel loading
Traffic Engineering
• Traffic Requirement
• The Erlang per subscriber
• Grade of Service (GoS)
• GoS is expressed as the percentage of call attempts that are blocked during peak traffic
• Most cellular systems are designed to a blocking rate of 1% to 5% during busy hour
Traffic Engineering • Frequency Reuse
• In designing a frequency reuse plan, it is necessary to develop a regular pattern on which to assign frequencies
• The hexagon is chosen because it most closely approximated the coverage produced by an omni or sector site
• Common reuse factor : 4/12, 7/21
Traffic Engineering
• Channel Loading
• As the number of TRX increases, the control channels required increases accordingly
• The following channel loading is used for conventional GSM network
• For services such as cell broadcast, additional control channels might be required