RF SURVEYDefinition:-

It is Collection of database from the Field (According to the Customer Planned Region that is Nominal Point/ Reference

the Area) for checking the feasibility of Cell Site ,fordeciding Coverage Region of Cell Site & for Deciding the

Link/Connectivity with the another Cell Site.

NOMINAL POINT This is a reference point given by customer

forRF survey work. This may be in any of thefollowing form : Latitude and longitude value. X and Y co-ordinate. North/East co-ordinate. Area name.

Tools Required For RF Survey Works:-

1) GPS It stands for Global Positioning System and mainly manufactured by Garmin Co. . It is of two

types, viz, 12 channel GPS 72 channel GPS

It works on the basis of satellite signal so there may be some delay. So we should wait for sometime to take the data readings. And also, we should wait for 3D navigation to get the exact value of data.

The 72 channel GPS gives the accuracy of the signal. If accuracy value is minimum then the data value will have high accuracy and if the accuracy value is maximum then the data value will have low accuracy. The accuracy value should not be more than 20.

2) Magnetic compass It is used for checking antenna direction3) Binocular with high visual range.

4) Digital camera5) Ultimeter – for measuring AMSL value

6) Measuring tape.7) Laptop.

Software Tools Required:-

MapInfo Professional (Version 6.5,7,8,8.5,9) Path Loss (Version 3.0 & 4.0) RL Tool (Demo Version) Global Mapper (Version 7,8,9 & Now 10) Mint Tool (For MapInfo Tools) Cell Tool/ Make Sector/Sitesee (For MapInfo

Tools) Google Earth Microsoft Office

Types of Tower GBT ( Ground Base Tower) RTT ( Roof Top Tower) RTP (Roof Top Pole)

Ground Base Tower

Ground Base Tower mainly used in Sub-Urban, Rural & Highway Region. It may be of 4 legs or 3 legs Tower depends on the Vendor & Operator. In Dense Urban & Urban Area we use the GBT Very Rarely because space is not available easily. In Most of the cases GBT is used for Coverage Sites. Standard height is given below from AGL (Above Ground Level).

Avg. Tower height-30-60 metr Regarding GBT We Select 60M & 70M Height of Tower

in Critical Situation that is Only When Link is Not Cleared In Lower Height & For That we have to take permission from the Customer End. This required space & Height of Tower Also Varies from Vendor & Operator .

Roof Top Tower

It is mainly used in Dense Urban, Urban & Sub- Urban Region. Very Rare in Rural & Highway Region. It may be 4 legs or 3 legs Structure of Tower that depends on Vendor & Operator. In Most of the Cases RTT is used for Capacity Sites. Standard Height Given Below From ARL (Above Roof Level).

Avg Tower Height-18-27 meter

Roof Top Pole

We mainly uses in a flat terrain where average Clatter height is Uniform, required to give the coverage only for less distance or Height of the building is G+6 or more. In this Type we are using small Pole type of Structure for Mounting GSM & Microwave Antenna. It may be integrated all three sector in same pole or in different-different Pole.

Standard Height of Roof Top Pole is 3M, 6M & 9M from ARL (Above Roof Level).

Types of RF survey

RND (Radio Network Design) survey. TND (Transmission Network Design)

survey. 

RND SURVEY

It is Used for Deciding the Coverage Zone of a Cell Site & Feasibility of Cell Site For that We have to Decide the Following thing

1. Cell Site Location Point (Candidates). 2. Orientation/Azimuth of GSM Antenna. 3. Height of GSM Antenna. 4. Tilt of the GSM Antenna

Types of RND Survey:-

Coverage Site Survey ( New Site Survey / New Town Survey / Rural/ Highway Region Mainly)

Capacity Site Survey ( Off Loading of Cell Site that is For High dense Populated region, Urban Region, Sub-Urban Region)

Coverage Site Survey Planning

Step By Step Process:-

1)According to the Planned Data Search the Nominal Point by using GPS.2)Check the Nominal Point is Feasible (Can Give the Coverage to desired Region with Full

Efficiency & less Disturbance) or Not (If nearby Obstacles is there, water Body is there, Less Population Zone etc.)

3)If Nominal is Not Feasible than Convey the message to Project Co-ordinator & Check another Nominal Point.

4)If Feasible than Decide the Search Ring For Cell Site Location.5)Start Collecting the Hot Spot throughout the Decided Coverage Region in all 360 Direction. 6) Coverage Area Can be Decided by Checking the Following Parameters:- Frequency Band Neighbor Cell Site Distance AMSL Variation Population Density of Area Nearby Obstacle Body like Hill/ Water Source.7) Store All the Hot Spot Information/ Obstacles Information/ Competitors Information in

GPS with Lat/ Long.8) Select the three Candidates (Possible Cell Site Location Point) on the Basis of Priority. It

may be GBT/ RTT/ Sharing Site.

Terms & Conditions for Selecting the GBT

Space Avability According to the Decided Tower Height.

SBC (Safe Bearing Capacity) of Soil Should Match with Height of Tower that is Strength of Soil.

Transportation Facility. Power Connectivity. Nearby there should not be High Power

Transmission Line/ Railway Track. TND Link should possible from the Candidate. Candidate should be Feasible in All Respect

Terms & Conditions for Selecting the RTT

Height of Building & Strength of Building should be according to Height of Tower.

Space Avability for Tower/ BTS according to the Height of Tower.

Transportation facility means wide road should be there.

Power Avability Nearby there should not be High Power

Transmission Line/ Railway Track. Dummy pillars /Separate Stairs Buildings provide

first Preference. TND Link should possible from the Candidate

Terms & Conditions for Selecting the Sharing /Co-location Cell Site

Space Avability on the desired height for GSM Antenna & Micro Wave Antenna.

Space Avability for the New BTS/ Battery Bank /Cable in Cable Ladder. Space for Making Earthling. Power Avability that is MCB Capacity. TND Link should possible from the Candidate.1) After Selecting the Candidate Decide the Height of GSM Antenna. For that

check the following details:- Desired Coverage Area. Average Clatter Height. Distance B/W Neighbor Cell Site. AMSL Variation throughout the Coverage Zone. Neighbour Obstacles Height.2) Decide the Height of Tower, by Checking the Height of Microwave Antenna

& GSM Antenna.3) Decide the Orientation of GSM Antenna according to the Hot Spot

Collected on Coverage Zone.

Capacity Site (off Loading) Survey Planning

Step By Step Process:- According to the Planned Data Search the Nominal Point by using GPS. Check the Feasibility of Nominal Point ( by Checking the Customer Complain Zone,

Nearby Cell Site Distance, Orientation Of Neighbor Cell ) If Nominal is Not Feasible (Means May be the Neighbor Cell Site Distance is Very Less

May Cause for High Interferences) than Convey the message to Project Co-ordinator & Check another Nominal Point. Than Shift the Nominal towards the Far Distance from the Existing Cell Site.

If Feasible than Decide the Search Ring For Cell Site Location. Search Ring Should Not be More than 50 M.

Select the Candidate within Search Ring if Not Available than inform to Project Co-ordinator after agreement move far from Search Ring for Candidates.

At the time of Deciding Orientation, Give Orientation towards the Conjunction area where required to OFF LOAD the sector.

Decide the Height of Tower, by Checking the Height of Microwave Antenna & GSM Antenna.

TND Link should possible from the Candidate. We can use the Net Monitoring Software Tool Help if Nominal Point is Not Given if

only area name is given. By using that we can check which area has poor signal level & how far the cell site from that place.

TND SURVEY It is the Path Study between the New Site

Point to the existing Site Point for Deciding the Height of Microwave Antenna that is for Fresnel Zone Clearance.

STEPS FOR TND SURVEY

1.Collect the database for new cell site and existing cell site that includes site Id,Latitude, Longitude, AMSL value, BRG angle, Hop-length, height of the obstacle.

BRG angle shows the direction of target point from your current location with reference to North direction. Hop-length is the shortest distance between new cell site and existing cell site.

2. Divide the hop-length into minimum 10 samples3. Measure the distance by GPS and after reaching the target (existing) cell site and check the following

parameters : Latitude value. Longitude value. BRG angle (at 180° phase difference). Hop-length should be same. Height of obstacle.

This entire process is called path study.

Note : Higher the number of samples, higher the accuracy.

4. Always collect the height of obstacle and AMSL value towards the line LOS (Line Of Sight) direction and as possible as nearer to LOS.

5. For deciding the height of antenna, insert all these details in RL tool and Path Loss tool. 

  

TND Survey on the basis of optical clearance

This type of survey is done when the road distance is very large compared to air-distance between two cell sites. Mainly it is used in hilly areas.

It includes following procedures :

1 Identify the existing tower and note some land-marks nearby.2. Now go to the new cell site and climb the tower to its top, and identify your existing tower

using binocular or with your naked eyes.3. Then check how much part of your tower can you see.4. If you can see more than 50% of your existing tower height then mark the point in your new

cell site.5. Go back to the existing tower and climb to the top of the tower and see your new cell site and

find if you can see the mark on your new cell site tower. If you can see then the microwave link is clear.

6. Mount the antenna above the marked point.Note : Tower should be visible upto 50% of its height otherwise there will be less Fresnel Zone

Margin. Precautions :

If required to mount large size microwave antenna then there should be a station available near the mounting point.

Microwave antenna

Microwave antenna is used for making link with another cell site. And the link is called microwave link. For connecting one cell site with another cell site we use microwave linking frequency.

There are totally 3 different microwave linking frequency which is divided on the basis of distance between two cell site. These are :

23 GHz for 0-3 Km 15 GHz for 0-10 Km 7 GHz for 10 Km and above Note : Higher the frequency, higher the loss, and

lesser is the distance, and vice-versa.

Need, Size and No. of Microwave link

Need of microwave link Every cell site must be connected with BSC

and MSC, directly or indirectly, so we need microwave link.

Size of microwave antenna The size of microwave antenna depends upon

the hop length. Larger the hop length, larger the size of the microwave antenna.

No. of microwave antenna : No. of microwave antenna depends upon the

no. of links between the cell sites.

Conditions for linking two cell sites :

One microwave antenna can make link with only one microwave antenna

Both the microwave antenna should face each other. i.e. there should be 180° phase difference between the two microwave antennas.

The size of microwave antenna in one cell site should be equal as that of the other microwave antenna in the other cell site with which it is linked.

Height & Structure of microwave antenna

Height of microwave antenna depends upon the Fresnel zone clearance height, maximum height of the obstacle and AMSL height

(AMSL – Average Mean Sea Level).On the basis of the path study between two cell site, we collect the samples, then by feeding these samples in our RL tool software we calculate the height of the microwave antenna.

The structure of microwave antenna depends upon the vendor

Different methods of connecting cell sites

The methods of connecting cell sites are : Microwave link OFC (Optical Fiber Cable) link

Used mostly by govt. sector No affect due to temperature or weather condition Maintenance cost is high

VSAT (Via Satellite) link Mainly used in hilly areas If nearby no other cell site is present Installation and maintenance cost is high Here we use TV station antenna

 

Height Of Tower & Gsm Anteena

Height Of Tower Height if tower depends upon the height of

microwave antenna and GSM antenna. Both the heights are taken Above Ground Level.

Example, Suppose, we have to find the height of GBT if the

heights of microwave antenna and GSM antenna are given as 33m and 30m, respectively. Then we decide the height of the GBT as 40m.

  Note : The minimum distance between microwave

antenna and GSM antenna in any tower should be 2m

GSM antenna

GSM antenna is responsible for radiating signal which we get in our mobile phone i.e. coverage in a specified region.

Specified region – in particular direction to a particular direction.

To give coverage for 360°, one antenna can cover 120°, so minimum no. of antenna required to cover 360° is 3.

120° is the maximum Beam-Width of the antenna and is not practically used.

 Size of GSM antenna

In GSM technology, we use 3 bands of frequencies, 900 Band or MHz or p. 1800 Band or MHz or p. 1900 Band or MHz or p. where, p is propagation frequency. These frequency band is constant in particular circle and changes with

change in circle. But BSNL operator uses 900 band in whole India. In ROC, Reliance GSM, Airtel and Idea operators use 1800 Band then

Aircel, BSNL and Vodafone use 900 Band. The size of antenna is directly proportional to the no. of electrical

components, the no. of electrical components is directly proportional to wavelength, and wavelength proportional to frequency.So we conclude,

Higher the frequency, smaller the size of GSM antenna Lower the frequency, larger the size of GSM antenna Note : Electrical components are the components with which the antenna is

made.

Height of GSM antenna

It depends upon 3 factors, Average height of clutter Required coverage area Nearby cell site distance Note : There is no software tool to find the

height of the GSM antenna. 

 Cables

Cables are used for the connecting the antenna with BTS (Base Transceiver Station). The cable used for this connection is co-axial cable. The characteristics of these cables are :

VSWR < 1.2 (VSWR – Voltage Standing Wave Ratio) No leakage in cable  Note : Higher the VSWR, higher the resistivity, and it reduces the radiation from the

antenna. Thickness of cable depends upon the frequency band. No. of cables : 2 in GSM antenna 1 in microwave antenna 1 earthing for whole cell site 1 earthing for equipments