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What kind of walkie-talkie is suitable for driving?

TDD-OFDM 解决方案的主要特点:

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How TDD-OFDM solutions work:

1. Point-to-point transmission

Manned/ unmanned aerial vehicle transmission system to the communicationcommand vehicle: front staff / unmanned aerial vehicles will be thescene of the real-time transmission of the image to the communicationcommand vehicles, commanders use the command vehicle display system,direct viewing the actual situation, Decision-making and execution. Thistransmission mode is suitable for medium and short distancetransmission, such as road survey, card check, daily patrol, criminalinvestigation and other small-scale tasks used.

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2. Relay transmission mode

Thefront-end transmission system of the soldier / communication vehicle /unmanned aerial vehicle is transmitted via the temporary relay to thecommunication command vehicle / airborne platform / suitcase to thecommand section: the individual transmission system can not transmit thesite due to the distance exceeding the man's coverage Audioand video real-time transmission to the communications command vehicle /airborne platform, this time need to increase the temporary relaystation. This model is more suitable for theenvironment more stringent long-distance transmission, such as thebasement inspection, building inspection, tunnel rescue, remote criminalinvestigation.

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3. More on the point of transmission

Accordingto the actual situation the commander may need from different angles tounderstand the situation at the same time to make accurate decisions,which requires better equipment compatibility. A communication command vehicle / command can simultaneously receive images from multiple front-end devices. This model applies to metropolitan area network / LAN large-scale operations, such as mass incidents. Major natural disasters.

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TDD-OFDM solution networking:

1. Mesh networking

Composedof mesh network digital wireless image transmission, a number of basestations to form a system, front-end collection by the roof PTZ,hand-held camera, the image, audio encoded by digital way through thebase station to the command center.

The remote equipment in the base station can be roaming, without human intervention. Command center can control the remote PTZ, direct communication or transmission of data. The system is shown in the figure.

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2. Chain-based networking

Individuals, airborne equipment or vehicle equipment can be self-organizing work. Each device can be used as a base station, the base station indirect transmission. as the picture shows.

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TDD-OFDM solution features and benefits:

1, the system transmission for the IP data stream, can achieve a variety of IP applications. Able to dock a variety of TCP / IP protocol based on the system network, such as satellite, fiber, 4G public network

2,can achieve multi-level signal relay, the signal relay after the basicno attenuation, after the signal relay attenuation<1%, the signalerror rate <10-6 (this can break through the wireless transmissiondistance limit, greatly improve the combat radius And combat depth), the specific application can be used inlong-distance signal relay and complex signal transmission, such as thebasement environment.

3, one-click operation that is self-networking

4, you can frequency range, 150MHz ~ 3GHz frequency points are available
5, the network equipment with a flexible, the use of unmanned aerialvehicles transmission equipment, individual transmission equipment,vehicle transmission equipment, relay transmission equipment, can beimmediately formed in the field of land, sea and air three-dimensionalapplication of operational command system.

6. In a single frequency to support two-way communication, high spectral efficiency, 8MHz bandwidth can pass up to 20Mbps.

7. High reception sensitivity, wide network coverage (receivingsensitivity up to -106dBm, 100 meters high to ground transmissionnetwork coverage radius of up to 20km).

8. Flexible allocation of channel resources, to achieve point topoint, point to multipoint, multi-point to multi-point two-waycommunication

9.All intelligent processing, support spectrum intensity perception,according to the scene to adjust the parameters of the equipment toensure optimal at any time.

 

What is TDD-OFDM? From its comparison with other technologies you can see:

技术/对比项

同频双向传输技术

公网

LTE

MESH

数字电台

COFDM单向图传  

多用户应用

单个频点自动分配  

单个频点固定分配

 

单个频点 固定分配

 

单个频点  自动分配

 

多个频点  固定分配

 

多个频点 固定分配

 

视频传输

支持

 

支持

支持

 

支持

 

不支持

 

支持

 

视频画质

高清/标清

 

高清/标清

 

高清/标清

 

高清/标清

 

不具备

 

高清/标清

 

视频传输数量

 

同时4路

 

同基站  2路标清

 

同时4路标清

 

同时4路标清

 

不具备视频传输能力

 

同时1路

 

信号延时

 

 

 

较小

 

较大

 

 

信号覆盖范围

 

 

中等

 

 

 

 

抗阻挡能力

 

较弱

 

中等

 

较强

 

 

抗干扰能力

 

较弱

中等

 

较弱

中等

 

移动传输能力

 

680公里/小时 高速

 

中速

 

 

 

 

中速

 

低速

 

高速

 

高速

 

基站依赖性

不依赖

 

非常依赖

不依赖

 

不依赖

 

依赖

 

不依赖

 

保密性

 

唯一同步码,128位AES加密,上层应用加密,黑白名单锁定等多重加密方式

保密性差

 

128位 AES 加密

 

128位AES加密

 

通用

 

 

128位AES加密

 

运营商费用

 

 

 

 

 

 

应急通讯能力

应急通讯能力高     安装简单  机动能力强   

低               几乎不具备

高 安装简单 机动能力强

高  安装简单  机动能力强

中等 基站电台受损则失效 

高  安装简单  机动能力强

 

独立的视频中继能力

 

高    大于4级中继  无马赛克 

不具备独立中继能力

 

中等  2级中继  无马赛克

中等   2级中继 无马赛克

 

不具备视频传输能力

 

极低单向技术,不适合中继

 

局域网数据交互容量

 

20Mbps

5Mbps

8Mbps

5Mbps

不具备数据 交互能力

 

不具备数据交互能力

 

应急追频组网功能

具备

 

不具备

 

不具备

 

不具备

 

不具备

 

不具备

 

TDD-OFDM solution Scope:

It can beapplied to a large number of images / voice / data between the military,the armed police, the national security, the fire, the air defense, theair defense, the traffic, the maritime rescue, the radio andtelevision, the health and epidemic prevention, the environmentalmonitoring, the oil field, the mine rescue, the security, Transmission, the device can be self-network, but also with the limited network with the use.

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Case 1When theincident occurred and emergency command vehicles and can not reach thescene, the same frequency two-way unmanned aerial vehicles canimmediately take off to reach the scene over the scene, the actualsituation map to the emergency command vehicle commander, commanderthrough no one The loudspeaker on the machine releases the order or reports it to the command center.

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Case 2:When thescene of the incident has not yet established a dedicated wirelessnetwork, the unmanned aerial vehicles and emergency command vehicles canbe composed of emergency network, by the emergency command vehiclecommander can be based on UAV aerial incident actual situation throughthe UAV on the speaker Direct command processing.

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Case 3: Whenthe scene of the incident away from the command center, but the natureof the event must be reported to the command center in a timely manner,in the public network completely paralyzed, the use of multiple commandvehicles without network center, the video information in time to thecommand center.

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Case 4When thescene in the valley or other long-distance transmission equipment cannot be achieved, you can use two UAVs out of the video signal to thecommand car.

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