1. Background

Dependable emergency communication plays a vital role in emergency response, especially in big city with large population, crowed traffic and  dense high buildings. Once the natural or man-made disaster happens, the first responders must be able to communicate reliably with all the human resources that are involved or will be involved. 

On 21st May 2019, IFLY techinical team and the law-enforcing department staffs in Xiamen conducted a testing to verify the performance of our Emmgergency Communication Network System. Let's learn how the system can help.

1. Background

• Tesing time

• Purpose of the testing

• Equipment list involved

• Testing location

2. Testing Contents

3. Preparation Work

• Tethered UAV

• Deploy the commad center

• Deploy the handset

• Configurate parameters

4. The entrie testing process

• The vehcile mounted CPE testing result

• The trunking handset testing result

5. Conclusion

Testing Time: 21-5-2019

Purpose of Testing is to:

• Verify the performance of "UAV 4G LTE private network base station" in urban environment.

• Test the performance and endurance of the Tethered UAV

• Verify the rapid deployment capability of the entire LTE private network system and the effect in practical application.

• Verify the coverage performance of the drone's onboard private network base station and the access capabilities of various types of terminals.

• Accumulate experience for selecting long-distance CPE installation locations.

• Optimize parameter configuration and propose product improvement suggestions based on the performance and testing result.

Equipment Involved In The Testing

• Six-rotor Tethered drone*1

• 600Mhz LTE private network All-In-One base station(Patron-A10)*1

• 70cm length airborne fiberglass antenna*1

• Patrol car*1

• Vehicle-mounted CPE*1(Model: Knight-V10)

• Vehicle-mounted Sucker antenna*1

• Vehicle-mounted Dome Camera*1

• Long distance manpack CPE*1((Model: KNIGHT-M2)

• 50cm length omnidirectional fiberglass antenna

• Broadband Trunking Handset*4(Cuckoo-HT2)

• Portable Multimedia Dispatching Console*1

• Feeders Cables, network cables, backup materials, etc.

Testing Location

Longitude: 117.743023

Latitude: 24.483360 

2. Testing Contents

1. The Airborne Lte Emergency Communication Base Station(Patron-A10)will be installed on the tethered uav. And during the testing, the tethered UAV will hover at different height to compare the different performance.

2. The patrol car equip with a vehicle-mounted CPE(Knight-V10)will patrol in the city to test how long distance does the base station(Patron-A10) can cover. 

3. Four people with Broadband Trunking Handset(Cuckoo-HT2)walk around the base station to test the effective range for the handset. 

4. The commander center located in a police station 3km for away from the UAV with a 2watts CPE(Knight-M2) is for commanding and dispatching rely on the dispatch console video and voice communication with patrol car and the four patrol people.

3. Preparation Work

Tethered UAV

① Rapidly deploy drone and airborne base station after arriving at the test site:

② Fuel the generator and turned it on quickly. 

③ Place the drone in the center of the site and deploy the power cord required by the drone

④ Connect the system to the power source and wait for the takeoff command. 

The entire process took 9minutes.

Deploy The Command Center:

① The command center was deployed in the security room of the Public Security Building. 

② Install the CPE, antenna, Portable Multimedia Dispatching Console.

③ Power the equipment. Wait for the system running normally. 

④ Wait for the start command .

The entire deployment took 2minutes.

Deploying The Patrol Car

① Install the camera, LTE 4G Private Network CPE and antennas on the patrol car.

② Power on the system and wait for the system to work normally.

③ Wait for the start command.

The entire deployment took 2minutes.

Deploying the handset

① Four staff members hold one Broadband Trunking Handset in their hand and ready to walk around the station.

The entire deployment took 1minute

Configurating and Inspecting The System Main Parameters:

• Base station frequency band: center frequency 594 MHz, 10M wireless bandwidth.

• Base station power: single channel 10W with 6dbi antenna.

• Vehicle-mounted backhaul CPE default power: 5W with 3dbi antenna.

• The Broadband Trunking Handset default power: 200mw and the antenna gain is 1.5dbi.

4. The Entire Testing Process

1. The drone took off and hovered at 80~ 90meters height. 

2. the patrol car departed according to the scheduled route.The camera’s video was send back to command center via the CPE in real-time 

3. The four patrol personnel began to walk around at random and communicate with the command center in real time by voice and video.

The vehcile mounted CPE testing result

The Patrol Car Drives Along the Road Towards to the Bridge.

Video during the entire driving process from the starting point to the bridge is clear and smooth, and there is only a short time stuck when the car turning a corner. And the corner is 7.4km away from the UAV base station. The specific test process is shown below (green for smooth video, yellow for stuck video, red is lost video connection)

There is continuous high-rise blockage between the signal interruption position of the vehicle CPE and the drone. The arrow below shows the occlusion situation:

The figure right shows the last video screen seen by the command center. After the vehicle enters the depth of the building and the auxiliary road of the Bridge, the signal is completely blocked and the signal connection is interrupted.

The picture on the left show the car travels in the opposite direction of the first route. After a period of time, the patrol car was quickly blocked by a mountain, and then the CPE lost the connection, but the video quality was very high before the loss. The specific test process is shown in the below figure (green for smooth video, yellow for stuck video, red for lost video connection)

Broadband Trunking Handset Test Results

The effective transmission distance of the Broadband Trunking Handset is about 3.8km. The quality of real-time video transmission during the test is very high. Except the video is slightly stuck at the place 1.3km from the drone because of signal blocked, and during all the rest places the video is smooth and clear. The specific test process is shown in the following figure:

(green for smooth video, yellow for stuck video, red for lost video connection)

Conclusion

Compared with other emergency methods, the solution that deploys base station in the air through UAV has the characteristics of faster deployment, more flexible networking, wider coverage, and larger user capacity.

This test verified the working performance of the airborne integrated base station (BBU+RRU+dispatching station+core network) on the tethered drone. The whole system need a short deployment time to achieve quickly respond to on-site emergency communication command requirements. During the entire test, the UAV hover time is 3 hours and 40 minutes.

According to the test results, in order to avoid mountain or high building blocking signal transmission, the hovering height of the drone can be raised to solve the problem. The effective coverage radius of the airborne base station is about 10km. In suburban environment, the deployment point can be selected within the range of 5-7km, and in urban environment, the deployment points can be selected within 3-5km.