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COFDM Classification in Wireless Transmission

COFDM (Κωδικοποιημένη Ορθογώνια Πολυπλεξία Διαίρεσης Συχνότητας) is one of the most reliable transmission technologies for UAVs, μη επανδρωμένα οχήματα, and wearable systems. Its strong anti-multipath capability, support for NLOS (μη οπτική επαφή) μετάδοση, and adaptability across wide frequency ranges make it a cornerstone in βίντεο ασύρματου, ήχου, και συνδέσμους δεδομένων.

Στο ασύρματο κιβώτιο UAV, COFDM systems can be classified according to several standards:

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1. By Device Type

• COFDM πομπούς

  • Devices dedicated to sending video, ήχου, and data streams.

  • Typical use: UAV airborne modules, body-worn transmitters, vehicle-mounted transmitters.

• COFDM Receivers

  • Devices for decoding and outputting signals (HDMI, CVBS, IP, or recording).

  • Common in ground stations, κινητά κέντρα διοίκησης, or monitoring systems.

• COFDM Transceivers

  • Προμηθεύω bidirectional communication: κάτω σύνδεσμος βίντεο + telemetry or control uplink.

  • Essential for advanced UAV applications requiring integrated command and monitoring.

  • The uplink and downlink can be set to different operating frequencies.

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2. By Transmission Direction

• Unidirectional COFDM

  • Μονόδρομη μετάδοση, π.χ., video from UAV to ground.

  • Lower complexity and cost, often used for FPV video or broadcast.

• Bidirectional COFDM

  • Two-way link supporting both κάτω σύνδεσμος βίντεο και telemetry/control uplink.

  • Enables full integration of video, flight data, and control feedback in one system.

• Unidirectional Video and Bidirectional Data

  • One-way video transmission and two-way data transmission, mainly used for ground robots and remote control vehicles.

• COFDM Relay / Repeater between Transmitter and Receiver

  • A COFDM relay receives, amplifies, and retransmits the signal between the transmitter and receiver to enhance its strength and coverage.

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3. By Transmission Content

• COFDM Video Transmitters

  • Focused on sending live video from UAV cameras.

• COFDM Video + Telemetry Data Transmitters

  • Combine βίντεο σε πραγματικό χρόνο με GPS, αισθητήρας, and flight control data.

  • Common in surveillance drones, inspection UAVs, και αιτήσεις άμυνας.

• COFDM Audio Transmitters

  • Σχεδιασμένο για φωνητική επικοινωνία or audio-only streams.

  • Can be used standalone or in parallel with video systems.

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4. By Signal Input Interface

• HDMI Input COFDM Transmitters

  • Connect directly to HD/4K cameras with HDMI output.

• SDI Input COFDM Transmitters

  • Επαγγελματικός, υποστηρίζοντας HD-SDI/3G-SDI cameras for broadcast and cinema drones.

• CVBS Input COFDM Transmitters

  • Legacy analog video interface (ΤΟΥ).

  • Used in cost-sensitive or backward-compatible UAV systems.

• AHD Input COFDM Transmitters

  • Συμβατό με Αναλογική Υψηλής Ευκρίνειας κάμερες (720p/1080p).

  • Often used in security and industrial UAV setups.

• Δίκτυο (IP) Input COFDM Transmitters

  • Accept IP streams from network cameras or encoders.

  • Flexible for UAVs carrying thermal imagers, AI vision modules, or IP PTZ cameras.

• Audio Input COFDM Transmitters

  • Dedicated for microphone/line-in sources for real-time voice communication.

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5. By Frequency Band

• Low-to-Mid Band COFDM (170-860 MHz)

  • Strong penetration and long-distance coverage.

  • Useful for NLOS UAV operations in urban or forest environments.

• High Band COFDM (860 MHz–6 GHz)

  • Higher bandwidth for HD/4K video.

  • Απαιτεί frequency down-converters for cofdm video receiver.

  • Common ranges: 1.2 GHz, 2.4 GHz, 3.3GHz, 5.8 GHz.

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6. By Form Factor / Στέγαση

• Mount Metal box – CNC customize, 1U or 2U chassis for ground stations or integrated command centers.

• Module-Only – customers provide their own enclosure, ΡΑ, and cooling solutions.

7. Επιλογές προσαρμογής

• ΡΑ (Ενισχυτής) – built-in or external
• How many watts of amplifier – 1-watts, 2-βατ, 5-βατ, 10-βατ, 20-βατ, 50-βατ

• Φίλτρο – low-pass, band-pass, or custom filters; can be applied to transmitters, δέκτες, ή και τα δύο.

• Τύπος περιβλήματος – 1U, 2U rack, or custom housings for UAV/vehicle/wearable integration

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8. By Deployment Platform

• UAV-Mounted COFDM Transmitters

  • Συμπαγής, πυγμάχος ελαφρού βάρους, optimized for airborne use.

  • Βασικά χαρακτηριστικά: χαμηλή κατανάλωση ενέργειας, vibration resistance, αποτελεσματική ψύξη.

• UGV-Mounted COFDM Transmitters

  • Installed on unmanned ground vehicles or robots.

  • Focus on long endurance and high-penetration communication.

• Body-Worn COFDM Transmitters

  • Designed for soldiers, journalists, or rescue teams.

  • Provide live video/audio streaming while being mobile.

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Περίληψη

COFDM in UAV wireless transmission can be classified by:

• Device type (πομπός, δέκτης, transceiver),

• Κατευθυντικότητα (one-way vs. αμφίδρομη),

• Transmission content (video only, βίντεο + τηλεμετρία, Μόνο ήχος),

• Input type (HDMI, SDI, CVBS, AHD, IP, ήχου),

• Ζώνη συχνοτήτων (170–860 MHz vs. 860 MHz–6 GHz),

• Επιλογές προσαρμογής ( Ενισχυτής, Φίλτρο, Enclose Type),

• Deployment platform (UAV, UGV, φορεμένο στο σώμα).

This layered classification makes COFDM highly adaptable across industries: UAV aerial surveillance, αναμετάδοση, άμυνα, αντιμετώπιση έκτακτης ανάγκης, ρομποτική, and wearable communication systems.