Radio Interference Cases in Satelli te Services
Radio Interference Cases in terrestr ial services01
02
Radio Interference Cases in terrestrial services01
1.Portable Devices2.Directional Antenna
1.Fixed station2.Monitoring Vehicle3.Portable devices etc.
General Steps
1.Characteristic analysis2.Where the interference may come from
1
Interference analysis
2
DF
3
Finding
1
Brief Introduction
• EVDO does not work.
• Uplink signal alarmed from Base
station
• A high level signal at 828.4MHz
• The position of the transmitter is
unknown.
1Case 1: Interference in CDMA System
With the signal strength and DF results,
we can determine the suspect building.
1Case 1: Interference in CDMA System
Distance Measuring Equipment (DME)
Working Frequency: 962~1213MHz
Security threat to civil aviationInterfere the DME communications
1Case 2: Interference in CIVIL Aviation Application
The signal strength is about -15dBm.
interference source
The interfered DME stationWorking frequency:1107MHz
1Case 2: Interference in CIVIL Aviation Application
RF parameters
• Transmitting frequency: L-band
(1.0-1.5GHz), S-band (2.3-2.7GHz),
Ku-band (10.7-12.7GHz).
• Transmitting power: 20~33dBm.
• Bandwidth: 2~8MHz.
Wireless Video Transmitter
1Case 2: Interference in CIVIL Aviation Application
What is Wireless VEDIO TRANSMITTERS Used for?
Oil fieldForest fire prevention
Water projectPublic security
1Case 2: Interference in CIVIL Aviation Application
Case 3:Harmonic of Broadcast
• Civil aviation air-ground communication
frequency 119MHz is interfered.
• The interference is come from the 10th harmonic
of AM 11.94MHz broadcast.
1
Road Cycling timing system interference in the Olympic Games
• Interference appeal shows Road Cycling timing system which is working at 125kHz is affected by unknown discrete signal.
1-2Case 4:Interference in Timing System
1
WLAN interference in Olympic Games
• In the northeast corner of Olympic Sports Center stadium, the networkpacket loss rate for WLAN service is about 60%, the network connectionis interrupted.
• According to spectrum monitoring, The interference signal level is 40dBmore than WLAN signal.
Case 5: Interference in WLAN System1
常见的霓虹灯Case 6: Research on Neon Light Interference
1
– (1) Neon self-generated interference• Manufacturing process defects, defective, aging;
– (2) Interference generated by the installation process
– (3) Interference generated by the transformer• Transformer overloading, housing ungrounded, etc.;
– (4) Interference generated by the control circuit• Spark flashes caused by the controller
– (5) Other reasons• Power line coupling, leakage caused by high voltage discharge, etc.;• Rain, snow, lightning and other inclement weather;
Case 6: Research on Neon Light Interference1
Case 6: Research on Neon Light Interference1
1GHz~6GHz, Light OFF
20
30
40
50
60
70
80Level [dBµV/m]
1G 2G 3G 4G 5G 6GFrequency [Hz]
峰值测量值平均值测量值参考峰值门限参考平均值门限
20
30
40
50
60
70
80Level [dBµV/m]
1G 2G 3G 4G 5G 6GFrequency [Hz]
峰值测量值平均值测量值
参考峰值门限参考平均值门限
1GHz~6GHz, Light ON
30MHz~1GHz, Light OFF
0
10
20
30
40
Level [dBµV/m]
30M 50M 70M 100M 200M 300M 500M 700M 1GFrequency [Hz]
测量值参考门限值
5
10
15
20
25
30
35
40
Level [dBµV/m]
30M 50M 70M 100M 200M 300M 500M 700M 1GFrequency [Hz]
测量值参考门限值
30MHz~1GHz, Light ON• Neon Works Properly:
– In 30MHz~1GHz bands, neon leaks a small amount of electromagnetic, radiated power is less than the reference level.
– In 1GHz~6GHz bands, neon leaks a small amount of electromagnetic, radiated power is less than the reference level.
• Overall, neon devices will not cause radio interference signal when it works properly.
Case 6: Research on Neon Light Interference1
• Neon Works abnormal(electrode virtual connection and arcing):
– In 30MHz~1GHz bands, neon leaks a wide spectrum electromagnetic energy, and the radiation energy is relatively high.
– In 1GHz~6GHz bands, the electromagnetic leakage mainly concentrated in 1GHz~2GHz.
• In general, when electrode is unstable, the electromagnetic interference spreads from 30MHz to 2GHz.
30MHz~1GHz, Light OFF 30MHz~1GHz, Light ON
0
10
20
30
40
50
Level [dBµV/m]
30M 50M 70M 100M 200M 300M 500M 700M 1GFrequency [Hz]
MES mobile_preLIM 40-47 Field Strength QP Limit
10
20
30
40
50
60
Level [dBµV/m]
30M 50M 70M 100M 200M 300M 500M 700M 1GFrequency [Hz]
MES lamp-1_preLIM 40-47 Field Strength QP Limit
1GHz~6GHz, Light OFF 1GHz~6GHz, Light ON
20
30
40
50
60
70
80
Level [dBµV/m]
1G 2G 3G 4G 5G 6GFrequency [Hz]
MES 1212-12_preMES 1212-12_pre2
LIM EN55022_1-6_PK_B Field Strength QP LimitLIM EN55022_1-6_AV_B Field Strength QP Limit
20
30
40
50
60
70
80
Level [dBµV/m]
1G 2G 3G 4G 5G 6GFrequency [Hz]
MES lamp-6_preMES lamp-6_pre2
LIM EN55022_1-6_PK_B Field Strength QP LimitLIM EN55022_1-6_AV_B Field Strength QP Limit
• Typical case of neon interference:
– Aviation interference• Continuous noise blocks the air-ground communication;
• Affects aircraft movements;
• Noise affects the ground command tower;
– Cable television network interference• TV screen appears black lines;
• Some channel appear snowflake-shaped interference;
– Cluster communication interference• Affects cluster radio communication;
– GSM interference• Affects call quality;
Case 6: Research on Neon Light Interference1
Size of the LED Screen: 25m*14mPeak Power:270kW
Case Study :LED Screen Interference
Legal SignalInterference Signal
1
Illigal radio station pretending to be a base station
Send spam message to GSM users in fake phone
number.
Collect the SIM cards information from the users
around.
The pseudo base station is composed of transmitter,
transmit antenna and control software.
Specific Case 7: Pseudo Base Stations1
In building
In vehicle
Antenna
1Specific Case 7: Pseudo Base Stations
Giant profits
Sending spam messages by using
pseudo base station will make
great profits.
Bypass the supervision
Bypass the supervision of telecom
administrator and operators.
1Specific Case 7: Pseudo Base Stations
Illegally occupying frequency resource
Deteriorating the EM environment by
high-power transmission
Interfering normal telecom provider’s
business
Phone users out of service
Pseudo Base station
Bad social Influence
1Specific Case 7: Pseudo Base Stations
Recognition the Pseudo Base Station
High frequency of location update
Monitor the location update frequency
Mobile phone connect with the pseudo base station shortly, so it would cause a mass of location update
1Specific Case 7: Pseudo Base Stations
Recognition the Pseudo Base Station
Monitor the SMS length
No voice call service,but send a lot of SMS in same length
No voice call service,and send a lot of SMS in same length
1Specific Case 7: Pseudo Base Stations
message length
Recognition the Pseudo Base Station
Monitor the LAC value
LAC(Location Area Code ) value is different from its adjacent BS
Monitoring LAC value
1Specific Case 7: Pseudo Base Stations
Locating with handheld monitoring equipment
Handheld reciever The hidden handheld direction finder
1Specific Case 7: Pseudo Base Stations
1Specific Case 8:Monitoring on Cheating
in Examinations
3
2
1
3. Transmit the answers back to whom buy this kind of service in the room.
1. Obtain the questions in the examination room and transmit by radio equipment.
2. Solve the questions outside the room.
Receiver system of voice equipment
Rad io Moni to r ing on Cheat ing in Examina t ion1
Specific Case 8:Monitoring on Cheating in Examinations
Use GPRS network to automatic log
on the server and control the
transmitter.
Reduce the risk of field operation.
Two options of power supply: 220V
AC/ 12V DC
The look is just like an eraser.
1Specific Case 8:Monitoring on Cheating
in Examinations
Center frequency 242.1MHz,
Band width 12.5kHz,Power
100W,Modulation type 2FSK.
Transmit 120 Chinese characters
with a interval of 6 seconds.
1Specific Case 8:Monitoring on Cheating
in Examinations
How does the management department of radio to
avoid the cheating in examination ?
Rad io Moni to r ing on Cheat ing in Examina t ion
Electronic Dog Metal Detector
Radio Shielding Devices
1Specific Case 8:Monitoring on Cheating
in Examinations
Radio Interference Cases in Satellite Services 02
2Interference Cases in
Satellite Services
Two types of radio frequency interferences; i.e. unintentional and intentional
A. Unintentional interference is primarily caused by: – faulty operation – equipment failure– poor system design– bad installation– interference from adjacent satellites– interference caused by terrestrial services
etc.
Classification of the interference
Classification of the interference
Two types of radio frequency interferences; i.e. unintentional and intentional
B. Intentional interference - illegal occupation by unauthorized users- Jammer to Satellite TV receiver
Few cases are destructive• Cut-off the satellite communication• Inter-cut of TV programs • Result in bad influence in society
2Interference Cases in
Satellite Services
1. Geo-location
2. Ground Searching
02Interference Cases in
Satellite Services General Steps
- Receive the downlink signal from the satellite transponder and measure the TDOA/FDOA parameters to estimate the location of uplink source. - Normally the Geo-location accuracy would be less than 10km.
Geo-location
1. Geo-location
2Interference Cases in
Satellite Services General Steps
-Portable devices-Monitoring Vehicles
Ground Searching
Monitoring Vehicles
-Portable devices
2Interference Cases in
Satellite Services General Steps
Innovational Technology to find the transmitter
Principle of Weak Signal detection
Weak signal detection in satellite interference finding
2Interference Cases in
Satellite Services
GSM基站发射塔
调制器 发射天线
转发上星
GSM Base Transceiver Station(BTS)(935-960MHz)
(950-1450MHz)
or(950-2150MHz)
Uplink
Transmit
Antenna
Modulator
Earth Station
Case 1:Interference from GSM Signals
- Interference from GSM Signals
2Interference Cases in
Satellite Services
• GSM Signals are TDMA signals, Geo-location system has poor performance to locate the TDMA signals.
• The frequency of service signal from the earth station is unknown, can not being used to locate the earth station.
-Difficulties in Geo-Location
2Interference Cases in
Satellite Services Case 1:Interference from GSM Signals
Modulation Mode
Modulated Rate
Single
Time Slot
ChannelBW
GMSK 270.833 577us 200kHz
- Characteristics of GSM Signals
2Interference Cases in
Satellite Services Case 1:Interference from GSM Signals
Time Slot
• MCC:Mobile Country Code, figure out in which country the cell is located• MNC:Mobile Network Code, figure out which network operator it belongs to• LAC: Location Area Code, figure out which location area it belongs to• CI: Cell Identity, Figure out the exact one cell
2Interference Cases in
Satellite Services Case 1:Interference from GSM Signals
Achieve the CGI information, especially its geographical location.
Signalcharacteristic
analysis
Decode to achieve
CGI
BTS location information
Identify the interference source
Investigation of the Interference
2Interference Cases in
Satellite Services Case 1:Interference from GSM Signals
MCC MNC LAC CI
460 1 10113 16252
1.05km
Earth Station
BTS
2Interference Cases in
Satellite Services Case 1:Interference from GSM Signals
Case 2: Interference in Satellite TV Receiver(1)
2Interference Cases in
Satellite Services
Case 3: Interference in Satellite TV Receiver(2)
2Interference Cases in
Satellite Services
Case 4: Jammer to downlink signal of Satellite TV
Traits- The whole C & Ku band interfered.- Thousands of families can’t watch TV normally.- Not only TV, but also others satellite system were interfered.
2Interference Cases in
Satellite Services
Case 4: Jammer to downlink signal of Satellite TV
Turn off the transmitter jammer
Notice- High building- From North to South- Monitoring Vehicle - LNA is necessary (filter)
2Interference Cases in
Satellite Services
Interfered INTERFERENCE SOURCE
Terrestrial Services
1.CDMA Repeater
2.DME(distance measuring equipment) Wireless Video Transmitter
3.AIR-TO-GROUDN communication 10TH harmonic of the HF broadcast
4. Road Cycling timing system Leakage of a broken signal cable
5. WLAN service Microwave Oven
6. Cluster Communication LED Screen
7. GSM system Pseudo Based station
8. Cheating equipment Cheating Radio Device
Satellite Services
1. Transponder GSM System
2. TV Receiver Wireless Bridge
3. TV Receiver Radar Signal
4. TV Receiver jammer
Summary of Interference