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Wireless technologies and their error rates

Short answer

HF radio uses ionospheric sky-wave refraction for long distance, with BER about 10^-2 to 10^-4. Terrestrial microwave uses line-of-sight directional dishes with repeaters every 40-60 km, giving BER about 10^-6 to 10^-9; satellite microwave gives about 10^-6 to 10^-8.

Describe the working principles of wireless communication technologies, including high-frequency radio, and microwave transmission. What are the typical error rates associated with these wireless technologies?

High-frequency (HF) radio (3–30 MHz)

            ionosphere (F, E layers)
           /\            /\
          /  \  refract /  \
  [Tx] __/    \________/    \__ [Rx]
       sky wave hops (1000s of km)
  • Long-distance communication by sky-wave propagation: the wave is refracted back to earth by the ionosphere, possibly in several hops, covering thousands of km without repeaters; ground wave is used for shorter ranges.
  • Simple equipment (transmitter, antenna such as dipole/rhombic, receiver); used for maritime, military, aviation, amateur and emergency links, and earlier for international telephony and remote districts in Nepal.
  • Limitations: the ionosphere changes with day/night, season and sunspot cycle, so the operating frequency must be changed to stay below the maximum usable frequency (MUF); fading due to multipath, noise and interference; narrow bandwidth (a few kHz) and low data rates.

Microwave transmission (1–40 GHz)

 [Dish]))))  ──── line of sight ────  ((((([Dish]
  Tower A        40-60 km hop           Tower B/repeater
  • Terrestrial line-of-sight links using highly directional parabolic antennas on towers; repeaters every 40–60 km (depending on tower height, earth curvature and Fresnel zone clearance).
  • Large bandwidth – carries hundreds to thousands of voice channels or high-rate digital streams (PDH/SDH); used for trunk networks and mobile backhaul.
  • Satellite microwave uses the satellite as a repeater in the sky (uplink/downlink, e.g. C and Ku bands).
  • Impairments: rain attenuation above ~10 GHz, multipath fading and obstruction; reduced by diversity (space/frequency) and fade margins.

Typical error rates

Error rate is given as the bit error rate (BER) = erroneous bits / total bits. Typical values (without heavy error correction):

MediumTypical BER
HF radio (sky wave)10−210^{-2} to 10−410^{-4} (poor, fading-dependent)
VHF/UHF radio, mobile10−310^{-3} to 10−510^{-5} before coding
Terrestrial LOS microwave10−610^{-6} to 10−910^{-9} (better in clear weather)
Satellite microwaveabout 10−610^{-6} to 10−810^{-8}
(Optical fibre, for comparison)10−910^{-9} to 10−1210^{-12}

HF needs ARQ and forward error correction for reliable data, while microwave links are designed for a BER of around 10−610^{-6} or better for most of the time.

✓ Answer checked by Claude Opus 5.5 (high effort)

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