Table of Contents
OFDM Technology Introduction
OFDM (Orthogonal frequency-division multiplexing, orthogonal frequency division multiplexing) is a multi-carrier digital modulation technology.
OFDM differs from AM/FM because it can transmit multiple high-speed signals using different frequencies at the same time. The result is bandwidth-efficient use of burst communications amid noise and other interference.
Traditional FDM (frequency division multiplexing) divides the bandwidth into several sub-channels, with guard bands in the middle to reduce interference, and they send data simultaneously. Tuning your receiver to the right station is necessary to watch cable TV or analog wireless broadcasts.
Using interference-free technology makes the use of available spectrum more efficient because guard bands aren’t needed. OFDM systems require much less bandwidth than traditional FDM systems.
OFDM Technical Characteristics
Anti-multipath fading and efficient use of frequency band resources
Based on the cyclic prefix, multipath interference is converted into useful signal multipath reception, reducing the impact of self-coherent interference and inter-symbol interference, and improving the channel’s ability to resist multipath fading. It is particularly suitable for use in high-rise buildings, kote ki gen anpil moun ak jeyografik enpòtan, ak zòn kote siyal yo gaye.
Efficient use of frequency band resources
OFDM technology uses FFT/IFFT algorithms to transform frequency domain signals, allowing multiple sub-carrier signals to be transmitted in parallel on a broadband channel, thus improving spectrum utilization efficiency. This is particularly important in wireless environments with limited spectrum resources.
Strong resistance to narrow-band interference
In a single-carrier system, yon sèl manyak oswa entèferans ka lakòz tout lyen kominikasyon an echwe, but in a multi-carrier system, only a small portion of the carriers will be interfered with. Error correction codes can also be used for error correction on these sub-channels. This technology can automatically detect which specific carrier under the transmission medium has high signal attenuation or interference pulses, and then take appropriate modulation measures to enable successful communication on the carrier at the specified frequency.
High flexibility
OFDM technology can adjust the number and spacing of sub-carriers in different application scenarios to adapt to different bandwidth requirements and has good flexibility.
OFDM Feature Products
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15km 30km 80km 150km longdistans san fil videyo transmetè reseptè transmisyon transceiver PA 2W 5W 10W
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10W PA 150KM ayeryèn videyo done lyen alontèm UAV san fil transmisyon transmetè reseptè bande laj meni taktik
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80KM san fil transmetè-reseptè Done Videyo RC transmisyon sistèm HDMI SDI long ranje latansi ki ba Vcan1702
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IP may ad hoc transceiver OFDM transmetè reseptè Wireless Videyo Done Transmisyon pou kamera IP abèy
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SDI oswa HDMI Pou IP ankode modulator CVBS H.265 H.264 kodaj tablo pcba Ethernet RSTP UDP pou UAV Drone Robotics
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IP may videyo done rezo transmetè transceiver Ad hoc rezo bande radyo
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7KM san fil videyo Done RC transmisyon sistèm long ranje ba latansi HDMI SDI 15km OFDM Vcan1643
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Mini Size HDMI Encoder Board sou IP Ethernet RJ45 Sorti modulator H.265 HTTP RSTP UDP ONVIF TCP
COFDM Technology Introduction
COFDM is coded OFDM (Kode OFDM). Some channel coding is added before OFDM modulation (error correction coding and guard interval are added before orthogonal modulation) to make the signal more reliable and effective transmission.
Applications of COFDM
OFDM, as a high-speed transmission technology that can effectively combat interference between signal waveforms, is more widely used in the field of broadband mobile communications. Pure OFDM wireless transmission systems are rarely used in actual systems, and are basically based on COFDM technology, such as DVB (Difizyon videyo dijital), LTE (4G), and WIFI.
Early COFDM wireless image transmission equipment mostly used improved DVB solutions, but there were problems such as two-way transmission, frekans bann, pri, elatriye, and it is rarely used in the current market. The bottom layer of common ad hoc network technologies on the market is mostly improved from LTE or WIFI technology.
WiFi technology is mainly used in stationary short-range and common applications. Its pilot subcarriers used for channel estimation are relatively sparse (sèlman 4 pilots under 20Mhz bandwidth). It is not effective in mobile scenarios such as UAV image data transmission and emergency communications. ideal;
LTE is designed for complex high-speed mobile long-distance scenarios, has a high pilot density (200 pilots under 20Mhz bandwidth), has stronger signal recovery capabilities, and is more suitable for areas such as occlusion and high-speed movement.
Konklizyon
An rezime, COFDM is coded OFDM, which adds channel coding to OFDM to provide communication system bit error performance. Our ad hoc network is based on LTE underlying technology (channel coding technologies such as OFDM multi-carrier, convolutional coding/TURBO coding) and is optimized and designed for complex scenarios such as drones and emergency communications.
COFDM Feature Products
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Pi bon FPV Videyo Transmetè Modil 170-860Mhz Wireless RF odyo Videyo Transmetè pou FPV Kamera 3W PA 50km
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30Km long distans COFDM HDMI Wireless Videyo Transmetè Reseptè konplè Set Audio Videyo TX RX pou UAV Drone 1080P 908T
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Wireless Videyo Transmetè ak Reseptè pou Kamera, HDMI HD H265 264 ankode 1W/2.5W PA 1080P60 Vcan1726
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30-milisgond Drone UAV HDMI Wireless transmetè videyo Ultra-ba-latansi sistèm transmisyon san fil Vcan1729
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COFDM modulatè demodulatè modil ankode dekodeur HDMI CVBS AV Antre AES 256 FHD RF difizyon
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Programme Komisyon Konsèy pou COFDM Wireless Videyo emetris
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COFDM san fil Ethernet transparan transmisyon modil 100M bps RJ45 FDD videyo done transmetè ak reseptè
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COFDM Digital videyo transmetè san fil HD reseptè transmetè videyo plen seri transmisyon pou dron kamera sekirite abèy
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Pòtatif Wireless Reseptè 7 pous Touch Screen COFDM Reseptè Digital Videyo Reseptè ak 7 pous ki monitè kè bebe