手法を比較

	レイ・トレーシング伝搬モデル	Multiple-Input Multiple-Output (MIMO)	直交周波数分割多重 (OFDM)	奥村・畑の経路損失予測モデル
分野	通信工学	通信工学	通信工学	通信工学
系統	Process / pipeline	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	1993	1995	1971	1968
提唱者	Maciel, Bertoni, and Xia	Telatar, Foschini, and Gans	Weinstein and Ebert	Masahiro Okumura and Masahiro Hata
種類	deterministic propagation algorithm	spatial multiplexing technique	multicarrier modulation scheme	empirical path loss model
原典	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.	Telatar, I. (1999). Capacity of multi-antenna Gaussian channels. European Transactions on Telecommunications, 10(6), 585-595.	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.	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.
別名	deterministic propagation, site-specific modeling	spatial multiplexing, antenna diversity	multicarrier modulation	path loss model, propagation prediction
関連	4	5	5	4
概要	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.	MIMO is a technique that uses multiple transmit and receive antennas to significantly increase channel capacity and reliability. Pioneered theoretically by Telatar (1999) and Foschini & Gans (1998), MIMO exploits multipath propagation—typically a liability in wireless—as an asset by creating independent spatial channels. It is now fundamental to all modern wireless systems including LTE, WiFi-6, and 5G, where it provides both capacity gains through spatial multiplexing and robustness through diversity.	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.