1CW Test
Introduction
CW test (Continuous Wave test) is an important step of Propagation Model Tuning. With the CW test data and Digital maps, the accurate Propagation Model could be gotten through model tuning.

Chapter 2 CW Test Workflow
Chapter 3 Analysis of CW Test Data
Internal Use
Section 1 Propagation Models
Section 3 Purpose of CW Test
Section 4 Basic Principles of CW Test
Internal Use
Propagation Models
Section 1 Propagation Models
Section 3 Purpose of CW Test
Section 4 Basic Principles of CW Test
Internal Use
Propagation model is used to predict the effect of terrain,
obstacle and artificial environment on the path loss.
WCDMA common propagation models


Common propagation models
Radio Propagation Model
Internal Use
+ K5log(d)×log(HTxeff) + K6(HRxeff) + Kclutterf(clutter)
d: distance between Tx antenna and Rx antenna (m)
K3: multiplier factor of log(HTxeff)
HTxeff: effective height of Tx antenna (m)
K4: multiplier factor of diffraction loss, which must be a positive value
Diffraction loss: diffraction loss through the path with barriers (dB)
K5: multiplier factor of log(HTxeff)log(d)
K6: multiplier factor of HRxeff
HRxeff : effective height of Rx antenna (m)
Kclutter: multiplier factor of for f(clutter)
f(clutter): average weighted loss caused by clutter
Model in UNET:





Section 1 Propagation Models
Section 3 Purpose of CW Test
Section 4 Basic Principles of CW Test
Internal Use
Purpose of CW Test
Compare CW test data with prediction results, and then tune the propagation parameters to improve the accuracy of coverage prediction.
GPS
Section 1 Propagation Models
Section 3 Purpose of CW Test
Section 4 Basic Principles of CW Test
Internal Use
Typification
The CW test data must represent the characteristic of electromagnetic wave in this area.
Balance
The CW test data must represent the characteristic of electromagnetic wave by the proportion of different clutters in this area.
Internal Use
Chapter 2 CW Test Workflow
Chapter 3 Analysis of Test Data
Internal Use
Section 3 Drive Test
Principles of site selection
Number of sites: It is usually agreed that a minimum of 5 sites should be tested in large and dense city, but one site is enough in the city, which mainly depends on antenna height and EIRP.
Representation: Site selection should aim to cover all types of clutter (from the digital map) in the coverage zone.
Multiple models: Define the corresponding zone of each model if the test environment requires multiple models to describe its propagation characteristics.
Overlap: Increase measurement overlap area between each site as much as possible. But reasonable inter-site distance should be ensured.
Obstacle: The data should be filtered in the subsequent processing if obvious obstacle exists.
Internal Use
Site Selection
a. Antenna height should be greater than 20m.
b. The antenna should be 5m higher than the nearest obstacle.
c. The obstacle mainly refers to the highest building on the roof where the antenna is installed. The building where the site is located should be higher than average height of surrounding buildings.
5GSM
Section 3 Drive Test
Tx subsystem: Tx antenna, feeder, high-frequency signal source and antenna holder
Rx subsystem: test receiver, GPS receiver, test software and laptop
High frequency signal source
Building Test Platform in Networking
Record the gain of the following parts on signals during networking:
Tx power of signal source
Loss of RF cable
Gain of Tx antenna
Gain of Rx antenna
Section 3 Drive Test
Keep to the following standards to select a test path
Landform: The test route must cover all main landforms in the area.
Height: The test route must cover landforms with different height in this area if the landforms are up-and-down.
Distance: The test route must cover different positions from the site in the area.
Direction: The test points must be consistent on the horizontal and vertical route.
LengthThe total distance of one CW test should be longer than 60km.
Number of test points: The more, the better.
Overlap: Overlap the test route in different sites as much as possible to improve the reliability of models.
Obstacle: Shadow areas behind this wall should be avoided when antenna signals are obstructed by the wall at a side.
CW2
The maximum vehicle speed: Vmax=0.8λ/Tsample
Delete test results from the sampled data under abnormal conditions:
Fading over 15~30db without reasonable causes
In tunnels
Under the viaducts
Select test routes from the main lobe coverage area if directional antennas are adopted for a CW test.
λλ/4
Internal Use
Chapter 2 CW Test Workflow
Chapter 3 Analysis of Test Data
Internal Use
Data to be filtered is as follows:
1. Data tested in the places where GPS is unable to locate accurately (such as under the overhead rack, in the tunnel).
2. Data obtained when the distance to antenna is too near or far.
3. Data obtained with too weak signals.
4. Error data caused by inexact AP (antenna pattern).
5. Other data inconsistent with the requirements during the route design of CW test.

20.1R2R R

3
15
r(x) = m(x)r0(x)
X: distance
r(x): received signals
r0(x): Raileigh Fading
m(x): local mean value, the combination of long-term fading and space propagation loss
2L: average length between sampling areas, also called intrinsic length
46.unknown
Internal Use
Data Dispersion
The CW test is to obtain the local mean value of each geography location in some areas as far as possible, i.e. the difference of r(x) and m(x) should be the minimum value. In this sense, effect of Raileigh Fading should be excluded.
When the intrinsic length equals 40 wavelength and the number of sampling points is 50, the difference of test data and actual local mean value can be less than 1dB according to Lee criteria.
Intrinsic length is average length for binning (2G band is 6 m long, namely, 40 wavelength)
Since the locating speed of GPS is far lower than the receiving speed of the receiver, the dispersion processing is required before the binning.
GPS150km/h14
Conditions:
There are many test records arranged under each locating point in time sequence because the receiving speed of the receiver is far higher than the locating speed of GPS.
The vehicle speed between two locating points is uniform.
The time interval between every two measurement records is the same.
Processing:
Equally distribute these records to the route section between two points in time sequence so that there will be sufficient points in every 6m range on test route.
E7476A18050km/h117
Objectives:
Reserve the impact of slow fading but eliminate the fast fading
Methods:
Method 1: make grids for the whole area with 6m side, perform the arithmetic average for the data located in each grid, and then take the grid center as the new location.
Method 2: divide the path into sections in equal interval with 6m for each, and perform the arithmetic binning for the data in each section to select some point for the location of mean value.
Tool: CW Data Editor
6
Data format imported to UNET is
Format conversion can be implemented manually (saved as .dat file)
X
Y
CW_Power_List__Freq__Hz
CW_Power_List__Ampl__dBm
Time
Date
X
Y
CW_Power_List__Ampl__dBm
5m
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