Porovnat metody
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| Ortogonální dělení frekvence (OFDM)× | Predikční model útlumu šíření Okumura-Hata× | |
|---|---|---|
| Obor | Telekomunikace | Telekomunikace |
| Rodina | Process / pipeline | Process / pipeline |
| Rok vzniku≠ | 1971 | 1968 |
| Tvůrce≠ | Weinstein and Ebert | Masahiro Okumura and Masahiro Hata |
| Typ≠ | multicarrier modulation scheme | empirical path loss model |
| Původní zdroj≠ | Weinstein, S. B., & Ebert, P. M. (1971). Data transmission by frequency-division multiplexing using the discrete Fourier transform. IEEE Transactions on Communication Technology, 19(5), 628-634. DOI ↗ | Okumura, Y., Ohmori, E., Kawano, T., & Fukuda, K. (1968). Field strength and its variability in VHF and UHF land mobile radio service. Review of the Electrical Communication Laboratory, 16(9-10), 825-873. link ↗ |
| Další názvy≠ | multicarrier modulation | path loss model, propagation prediction |
| Příbuzné≠ | 5 | 4 |
| Shrnutí≠ | OFDM is a multicarrier modulation technique that divides a wideband channel into many narrowband orthogonal subcarriers. Introduced by Weinstein and Ebert in 1971, it exploits the duality between time and frequency domains to efficiently use spectrum while mitigating intersymbol interference in frequency-selective channels. OFDM is now the standard for high-speed wireless systems including WiFi, cellular LTE, and digital broadcasting. | The Okumura-Hata model is an empirical propagation model for predicting path loss in mobile radio systems. Developed by Okumura (1968) and mathematically formalized by Hata (1980), it is one of the most widely used models for cellular network planning. The model predicts median path loss as a function of frequency, distance, and antenna heights, with environment-specific correction factors. Despite its age, the Okumura-Hata model remains a standard in 2G/3G planning and is often used as a baseline for more sophisticated models. |
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