Porovnat metody
Prohlédněte si vybrané metody vedle sebe; řádky, které se liší, jsou zvýrazněny.
| Model šíření pomocí sledování paprsků× | Ortogonální dělení frekvence (OFDM)× | Predikční model útlumu šíření Okumura-Hata× | |
|---|---|---|---|
| Obor | Telekomunikace | Telekomunikace | Telekomunikace |
| Rodina | Process / pipeline | Process / pipeline | Process / pipeline |
| Rok vzniku≠ | 1993 | 1971 | 1968 |
| Tvůrce≠ | Maciel, Bertoni, and Xia | Weinstein and Ebert | Masahiro Okumura and Masahiro Hata |
| Typ≠ | deterministic propagation algorithm | multicarrier modulation scheme | empirical path loss model |
| Původní zdroj≠ | Maciel, T. F., Bertoni, H. L., & Xia, H. H. (1993). Unified approach to prediction of propagation over buildings for all ranges of frequencies. IEEE Transactions on Vehicular Technology, 42(1), 41-45. link ↗ | 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≠ | deterministic propagation, site-specific modeling | multicarrier modulation | path loss model, propagation prediction |
| Příbuzné≠ | 4 | 5 | 4 |
| Shrnutí≠ | Ray tracing is a deterministic propagation modeling technique for predicting electromagnetic field strength at specific locations. Instead of empirical formulas (like Okumura-Hata), ray tracing traces paths of electromagnetic energy as it reflects, diffracts, and scatters off buildings and terrain. With accurate 3D geometry and material properties, ray tracing predicts site-specific path loss, multipath delay profiles, and angle of arrival, making it ideal for detailed coverage planning, interference analysis, and system design. Ray tracing is now standard in professional cellular planning tools. | 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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