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5 Advantages of COFDM Technology in Wireless Video Transmission

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Abstract: This blog mainly introduces the application characteristics and advantages of COFDM technology in wireless transmission, and the application areas of the technology.

Keywords: non-line-of-sight; Anti-interference; Move at high speed;COFDM

1. What are the common wireless transmission technologies?

The technical system used in wireless transmission can be roughly divided into analog transmission, data transmission/Internet radio, GSM /GPRS CDMA, digital microwave (mostly spread spectrum microwave), WLAN (wireless network), COFDM (orthogonal frequency division multiplexing), etc. Among them, traditional technologies cannot achieve broadband high-speed transmission under "blocked, non-visual and high-speed mobile conditions", with the development and maturity of OFDM technology, this problem has a solution.

 

2. What is COFDM technology?

COFDM (coded orthogonal frequency division multiplexing), that is, coding orthogonal frequency division multiplexing, in addition to the powerful coding error correction function, the biggest feature is multi-carrier modulation, which divides a given channel into many orthogonal sub-channels in the frequency domain, uses a single subcarrier on each sub-channel, and decomposes the data stream into several sub-data streams, decomposing the data flow rate, these sub-data streams are then used to modulate each subcarrier separately.

 

The parallel transmission of each subcarrier reduces the dependence on a single carrier, and its anti-multipath fading ability, anti-intercode interference (ISI) ability, and Doppler frequency shift resistance are significantly improved.

 

The use of COFDM technology can truly realize broadband high-speed transmission under obstruction, non-visual and high-speed mobile conditions, which is currently the most advanced and most promising modulation technology in the world.

3. What are the advantages of COFDM technology in wireless transmission?

Wireless transmission goes through two stages: analog and digital transmission.  Analog image transmission has been basically eliminated in many industries due to its interference and co-channel interference and noise superposition, resulting in poor effect in practical applications.

With the maturity of OFDM technology and components, products using COFDM technology have become the most advanced wireless transmission equipment. Its advantages are as follows:

1、It is suitable for application in None-line-of-sight and obstructed environments such as urban areas, suburbs, and buildings, and shows excellent "diffraction and penetration" ability.

COFDM wireless image equipment has the advantages of "non-line-of-sight" and "diffraction" transmission due to its multi-carrier and other technical characteristics,In urban areas, mountains, inside and outside buildings and other environments that cannot be seen and obstructed, the device can achieve stable transmission of images with a high probability, and is not affected by the environment or is less affected by the environment.

Omnidirectional antennas are generally used at both ends of the transceiver and receiver, and the system deployment is simple, reliable, and flexible.

 

2、It is suitable for high-speed mobile transmission, and can be applied to vehicles, ships, helicopters/drones and other platforms.

Traditional microwave, wireless LAN and other devices cannot independently realize the mobile transmission of the transceiver end and can only realize the transmission of mobile point to fixed point under certain conditions. Its system has many technical links, complex engineering, reduced reliability, and extremely high cost.

However, for COFDM equipment, it does not require any additional devices, it can realize the use of fixed-mobile, mobile-mobile rooms, and is very suitable for installation on mobile platforms such as vehicles, ships, helicopters/drones, etc. The transmission has high reliability and high-cost performance.

 

3、It is suitable for high-speed data transmission, generally greater than 4Mbps, to meet the transmission of high-quality video and audio.

In addition to the requirements for cameras, high-quality video and audio have very high requirements for encoding streams and channel rates, and each subcarrier of COFDM technology can choose QPSK, 16QAM, 64QAM and other high-speed modulation, and the synthesized channel rate is generally greater than 4Mbps. Therefore, it can transmit 4:2:0, 4:2:2 and other high-quality codecs in MPEG2, and the image resolution of the receiving end can reach 1080P, which meets the requirements of post-analysis, storage, editing and so on.

 

4、In complex electromagnetic environments, COFDM has excellent immunity to interference.

In a single-carrier system, a single fading or interference can cause the entire communication link to fail, but in a multicarrier C O F D M system, only a small percentage of subcarriers are interfered with, and these subchannels can also be corrected with error-correcting codes to ensure a low bit error rate of transmission.

 

5、Channel utilization is high.

This is especially important in wireless environments with limited spectrum resources, where the spectrum utilization of the system tends to be 2Baud/Hz when the number of subcarriers is large.

 

Apply COFDM technology to IWAVE’s wireless video transmitter

Currently COFDM is widely used in DVB (Digital Video Broadcasting), DVB-T, DVB-S, DVB-C etc. for high-speed UAV data transmission.

 

With the technology development, there are more and more drones and UAV serving for people in different project. IWAVE focuses on designing, developing, and selling wireless communication solutions for commercial drones and robotics.

The solutions are 800Mhz, 1.4Ghz, 2.3Ghz, 2.4Ghz and 2.5Ghz,5km-8km, 10-16km and 20-50km video and digital Bi-directional Serial Data Links with COFDM technology.

The top flying speed our system support is 400km/h. During such high speed the system can also ensure the video signal stable transmission.

 

For short range 5-8km, OFDM is used for UAV/FPV or Multi rotor video transmission for video, Ethernet signal and serial data such as FIP-2405 and FIM-2405.

For long range 20-50km, we recommend this series products like FIM2450 and FIP2420

IWAVE's adopts the advanced COFDM technology to our products, focus on developing the rapid deployment emergency communication system. Based on 14years of accumulated technology and experiences, we lead localization through reliability of equipment with strong NLOS ability, ultra long range and stable working performance in the UAV, robotics, vehicles wireless communication market

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Post time: Apr-20-2023