06 wcdma site survey

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WCDMA Site Survey

HUAWEI TECHNOLOGIES CO., LTD. HUAWEI Confidential

During WCDMA network construction, the survey on NodeB is intended to provide detailed construction solutions for the implementation of network construction to guide goods preparation, engineering construction, installation and debugging, and so on. The survey results may affect the quality and smooth implementation of a whole project.


After studying this course, you will be able to:

Be familiar with the process of NodeB survey.

Master the rules of selecting a NodeB site.

Understand the design of the antenna system.

Know the output documents during NodeB survey.


Chapter 1Chapter 1 Definition of Roles in NodeB Definition of Roles in NodeB SurveySurvey

Chapter 2 NodeB Survey Process

Chapter 3 NodeB Survey Report


Definition of Roles in NodeB Survey

Role definition

− Radio network planning manager: is responsible for the overall planning result as a general organizer for network planning.

− Network planning survey personnel: completes field survey including spectrum test and site survey under the guidance of the radio network planning manager, and outputs the Site Survey Report and Spectrum Test Report.

− Engineering survey personnel: cooperates with the network planning survey personnel to complete site survey.


Does the site meet the

requirement?

NodeB Survey Process

ideal sites list

Are the sites shared with 2G sites?

No

Output search rings

Obtain the alternative

sites

Perform site survey

Output a survey report

Yes

No

Yes


Coordination Meeting for NodeB Survey Before the survey starts, notify relevant personnel to participate in the Before the survey starts, notify relevant personnel to participate in the

coordination meeting for survey preparation and complete the following coordination meeting for survey preparation and complete the following tasks:tasks: Know the local electromagnetic background and conduct a spectrum test

if necessary. Determine and dispatch the survey and cooperation personnel. Prepare necessary vehicles and devices. Work out a survey plan and determine the survey route. If the area to be

surveyed is large, divide it into different parts and survey them at the same time.

Work out preliminary solutions for transmission and power supply. Communicate with the operator to determine the band, antenna azimuth

and tilt angle of the existing antenna system in the shared site. After fully communicating with the operator, make sure that the areas the

operator focuses on are within the coverage of the local site. Know these major coverage areas before the survey.


Preparations for NodeB Survey After knowing the general situation of the project, try your best to

collect various types of information related to the project, including:

Engineering file

Background information

Situation of the existing network

Local map marked with ideal sites

Contract configuration list

Latest NodeB survey form for network planning

WCDMA NodeB Survey Form


Preparations for NodeB Survey

Get in touch with the marketing personnel or the relevant personnel in the Engineering Department, and record the phone number of the regional office, operator’s address, contact’s phone number of the operator, as well as how to arrive at the site.

Prepare relevant tools and ensure that they are available before departure. The tools include:

Digital camera

GPS satellite receiver

Compass

Tape/laser rangefider

Portable computer

Telescope


Preparations for NodeB SurveyTool Usage Precautions

Digital camera

Used to take photos for the surrounding radio propagation environment, roof and shared site of the NodeB.

Charge the digital camera in time before using it and check the battery capacity. It is recommended to carry the camera charger.

GPSUsed to determine the longitude and latitude of the NodeB.

GPS can be used only when more than three satellites are searched. In addition, the GPS should be located in the place that is open enough. The projection format is set to WGS84 and the longitude and latitude format to XX.XXXX˚.

CompassUsed to determine the antenna azimuth.

Do not near the iron materials (including the antenna bracket and antenna pole) to ensure the measurement precision.

Portable computer

Used to record and save the data.

Tape Used to measure the length.

TelescopeUsed to observe the surrounding environment.

Laser rangefider (optional)

Used to measure the height of buildings.


Precautions on Selecting a NodeB Site The network planning personnel need to have an overall understanding of the coverage

area and determine the ideal sites.

The survey personnel select and survey the preplanned sites one by one. When none

of the sites meet the requirement, the network planning personnel need to determine

alternative sites.

For complicated coverage areas, the actual propagation test is sometimes needed to

check whether the candidate site can meet the coverage requirement.

After confirming an ideal site, you need to communicate with the landlord or the land

owner to buy or rent it.

If no alternative site meets the requirement, you need to re-select a NodeB or change

the coverage requirement till a site selection plan meeting the actual coverage

requirement is available.


Principles for Selecting a NodeB Site

Specific principles for site selection are as follows:a. The site should be located in the ideal position of the regular mesh. An alternative site should be selected from the R/4 search ring. Theoretical

site position


Principles for Selecting a NodeB Site b. In the case that the layout of NodeB is not affected, try to select the existing facilities to reduce

construction cost and shorten the construction period.

c. Avoid selecting a site on the mountain peak of a high altitude (100 m to 300 m higher than the altitude of the urban areas) at the edge of urban areas or in the suburban areas. This facilitates you to control the coverage range and reduces the difficulty of engineering construction, thus realizing convenient maintenance.

d. Build a NodeB in the place with convenient transportation, available mains, secure environment and few arable lands occupied.

e. Avoid building a site near a large-power radio transmitter, a radar station or other interference sources.

f. Build a NodeB in the place far away from the woods to avoid fast fading of the received signals.

g. Consider the impact of signal reflection and time dispersion when selecting a site in the mountainous areas, in steep or dense lake areas, in highland cities, or in environment with high-storey metal buildings.


Principles for Selecting a NodeB Site

h. Flexibly use the height of buildings when selecting a site among buildings in the urban area to realize network hierarchy.

i. When there are a few NodeBs at the initial phase of network construction, ensure that the major areas of the selected sites are well covered.

j. Avoid setting the cell edge in the dense user area. Good coverage means that there is only one primary coverage cell.

k. The first Fresnel zone of the antenna should be free from obstructions.

l. Consider construction on a long-term basis.

m. If a site is selected based on capacity expansion of the existing network, consider the compatibility with the NodeB in the existing network during site selection.


Typical Problems During Site Selection

Unreasonable cell layout imposes a great impact on network performance, which is more remarkable in the WCDMA network.

1. Weak signal zone and signal blind zone: Too long inter-NodeB distance, building obstruction and insufficient indoor coverage will cause weak signal zones and signal blind zones.



2. Too large overlapped coverage zone: When there are too many NodeBs, too short inter-NodeB distance, improper forward power allocation and bad control over cell coverage will make the inter-NodeB overlapped zone too large and cause a high softer handover ratio. Too many strong pilot signals will result in pilot pollution, BLER and even call drop.



3. Overreach coverage: Overreach coverage may occurs when you construct a NodeB on the high mountains in the urban or suburban areas or on the too high buildings. After you determine the site and the direction of the main lobe of the antenna and feeder, overreach coverage also occurs if the cell direction is consistent with the direction of such clutters with the waveguide effect as the streets and rivers.


Detailed NodeB Survey

Shooting the site After arriving at a site, take one to two photos of the overall structure of the entry

to the alternative site, the relevant building or the tower.

Collecting the longitude and latitude information of the NodeB Before collecting the longitude and latitude information using GPS on the top of a

building, set the coordinate format of the GPS to WGS-84 and the display format of the longitude and latitude to XX.XXXX˚. If the operator has other formats, set them as required by the operator.

Fill in Network Planning Survey Form for XXX Site in XXX Project on the site after getting the longitude and latitude information.


Detailed NodeB Survey Propagation environment surrounding the NodeB

Beginning with the North, record the height and the distance to the local NodeB of the buildings or natural barriers that have the same height as the antenna or are higher than the antenna in various directions within 500 m of the NodeB.

Shoot the surrounding radio propagation environment on the antenna installation platform: beginning with 0˚ (namely the North), shoot the surrounding radio propagation environment clockwise with the step of 30˚ from 12 directions. On each photo, you need to mark the shooting position and direction on the finished schematic diagram of the roof plane.

Observe whether there are antenna systems of other operators near the site and record them if any.

Others

Correctly fill in Network Planning Survey Form for XXX Site in XXX Project on the site.



Taking photos and drawing a sketch of the geographical location When taking photos, record the angle

information of photos for future archiving.



Taking photos and drawing a sketch of the geographical location Save the photos in the format that is as small as possible under the

condition that they can be viewed clearly.



Roof information Not constructed sites: On the

roof diagram, mark the installation position of the antenna and the basic direction of the cabling rack.

Constructed sites: The installation position of an antenna is restricted by many factors. The spatial position information of the antenna installation platform and the antenna and feeder parameters of the co-site heterogeneous systems affect the installation position of the antenna to a great extent.


Survey and Design of the Antenna System

As an important part of the NodeB system, the antenna system refers to the channel part from the antenna to the top of the cabinet. It consists of the antenna, feeder, jumper, tower-mounted amplifier, lightning arrester, grounding clip, feeder clip, feeder window, and so on.

Solution to the antenna system

Grounding facility

Jumper for the antenna and feeder

Fixing facility

Grounding facility

Indoor jumper

Tower for the antennas and feeders NodeB

Feeder


Survey and Design of the Antenna System

Tower mounted amplifier (TMA) is installed on a tower and is near to the antenna. A ½ jumper of 2m to 3m long is used to connect the TMA and antenna. The received signal from the antenna can be amplified by the TMA with a small attenuation. The TMA can improve system sensitivity and uplink coverage. In addition, it can also reduce the Tx power of the user equipment (UE) and noise interference within the system, thus improving conversation quality.

Tower mounted amplifier

Feed current of the tower mounted amplifier

Filter for transmitted signals

Filter for received signals

Bypass

Low noise amplifier

Antenna

Filter for received signals


Survey and Design of the Antenna System — Classification of Antennas

By the radiation direction:

Directional antenna and omni-directional antenna By the appearance:

Panel antenna, cap antenna, whip antenna and aperture antenna By polarization:

Single polarization antenna and dual polarization antenna


Survey and Design of the Antenna System—Selection of Antennas

Selecting an antenna for the dense urban and urban NodeB The directional antenna with a horizontal half-power angle ranging from

60˚ to 65˚ is usually selected to realize 3 sectors. Intermediate gain antenna (about 15 dBi) for low frequency band (UMTS

900MHz), High gain antenna (18 dBi) for high frequency band( UMTS 2000Mhz).

The antenna downtilt should be designed according to site situations, normally from 4˚ to 10˚ with suitable height.

Electric tilt angle antenna (ranging from 2˚ to 6˚) is recommended and antenna supported should realize 0˚ to 15˚

A dual polarization antenna is recommended. The main beam of antenna should be direct to high traffic area, import

buildings or regions (airport, emporium, gym, government, hotel, etc) Installed antenna locations should be far away to other system

transmitter (like GSM, CDMA, TV tower and other RF transmitter) to guarantee the isolation and without obvious obstacle to block or reflect.


Survey and Design of the Antenna System—Selection of Antennas Selecting an antenna for the suburban NodeB

Select a directional antenna with a horizontal half-power angle ranging from 65˚ or 90˚ according to the actual situation.

The intermediate or high gain antenna of 15 dBi to 18 dBi is selected according to frequency band and NodeB density.

The antenna downtilt should be designed according to site situations, normally from 0˚ to 6˚ with suitable height.

Generally, preset tilt antenna is unnecessary. Both dual and vertical polarization antennas can be used. The main beam of antenna should be direct to high traffic area,

import buildings or regions

Installed antenna locations should be far away to other system transmitter (like GSM, CDMA, TV tower and other RF transmitter) to guarantee the isolation and without obvious obstacle to block or reflect.


Survey and Design of the Antenna System—Selection of Antenna

Selecting an antenna for the rural NodeB Select a directional antenna or an omnidirectional antenna of 90˚

or 120˚ according to the actual situation and requirement. The gain of the selected directional antenna is usually high (about

18dBi). Generally, the antenna with a preset tilt angle is not selected and

downtilt was set as 0˚ . Electric tilt angle antenna (ranging from 0˚ to 10˚) can be used in special scenery (high mountain site)

The null filling antenna is preferred in the high NodeB (higher than 400m for directional antenna and 200m for omni antenna).

A vertical polarization antenna is recommended. Installed antenna locations should be far away to other system



Survey and Design of the Antenna System—Selection of Antenna Selecting an antenna for the NodeB on the road

Usually, the directional antenna with a narrow beam and high gain (21~22dBi) is selected. The 8-shaped antenna (14dBi), omnidirectional and deformed omnidirectional antenna (12dBi) can also be selected according to the actual situation.

The antenna with a preset tilt angle is usually not selected and downtilt was set as 0˚ . because the NodeB on the road has a high requirement for the coverage distance.

A vertical polarization antenna is recommended . The front-back ratio of the selected directional antenna should not be

too high. Installed antenna locations should be far away to other system




Selecting an antenna for tunnels For tunnels shorter than two kilometers

－ The 10-12dBi Yagi/log periodic antenna/panel antenna is recommended. You are usually recommended to install them at the tunnel entrance to cover road tunnels shorter than 2 km.

For tunnels longer than two kilometers

－ The leaky cables, coaxial cables and distributed fiber systems are

recommended.



Selecting an indoor antenna Omnidirectional antenna

－ Small, vertical polarization, and cap or cup antennas with the

gain of 2dBi are recommended. Such antennas are of good appearance and easy to install.

Directional antenna

－ Vertical polarization directional antennas with the horizontal half-power angle of 90˚ and the gain of 7dBi are recommended.


Survey and Design of the Antenna System—Installation of AntennaInstallation environment is divided into environment near the antenna and environment near the NodeB. For environment near the antenna, you need to consider the antenna isolation and the impact of the tower and the floor. For environment near the NodeB, you need to consider the impact of the buildings within 500 m on radio propagation.

Requirements for antenna installation against the wall

Clearance requirements surrounding the antenna


Survey and Design of the Antenna System—Installation of AntennaWhen installing the NodeB antenna, we need to consider whether the antenna will cause a large shadow in its coverage area. In addition, we also need to install the antenna in the place away from the barriers. For example, antennas should be installed along the edge of the building top to prevent the roof from obstructing radio signals.

Distance (m) from the antenna to the edge of the building

Height (m) from the bottom of the antenna to the roof of the building


Survey and Design of the Antenna System—Installation of Antenna

You can analyze mutual interference between the GSM BTS and the NodeB from the following aspects:

Blocking of the GSM BTS on the NodeB

Spurious impact of the GSM BTS on the reception band of the NodeB

Blocking of the NodeB on the GSM BTS

Spurious impact of the NodeB on the GSM reception band

Usually, to meet the isolation requirement for blocking and spurious emission, antenna isolation is required to exceed 30 dB when the WCDMA, GSM and DCS share a site.


Survey and Design of the Antenna system — Antenna Installation Spacing In space diversity, the spacing between two Rx antennas should range from 12 λ to

18 λ. 1 λ is equal to 0.15 m (2 GHz). The higher the antenna is installed, the larger the horizontal spacing of antenna

diversities is. Usually, the horizontal spacing of diversity antennas is 0.11 time as much as the valid height of the antenna.

To reach the same diversity effect, the vertical diversity spacing must be five to six times as much as the horizontal diversity spacing.

To reduce mutual impacts between two antennas, the horizontal spacing of diversity antennas need to exceed 3 m no matter what the valid height of the antenna is.

Diversity distance of the directional antenna


Survey DocumentsWCDMA NodeB Survey ReportInvolves the network construction background, pre-planning solution, NodeB engineering parameter list, NodeB distribution diagram, and so on.

WCDMA NodeB Survey Form during Network PlanningInvolves the antenna installation position, engineering parameters of various sectors, surrounding environment of the antenna, and so on.

Survey MemoWCDMA Engineering Parameter List

WCDMA NodeB Survey Report

WCDMA NodeB Survey Form

WCDMA Site Survey Memo

WCDMA Engineering Parameter List

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