เปรียบเทียบวิธี

	การแบ่งความถี่แบบออร์โธโกนอล (Orthogonal Frequency Division Multiplexing - OFDM)	ระบบอินพุตเอาต์พุตหลายหน่วย (Multiple-Input Multiple-Output: MIMO)	ทฤษฎีความจุช่องสัญญาณของแชนนอน
สาขาวิชา	โทรคมนาคม	โทรคมนาคม	โทรคมนาคม
ตระกูล	Process / pipeline	Process / pipeline	Process / pipeline
ปีกำเนิด	1971	1995	1948
ผู้ริเริ่ม	Weinstein and Ebert	Telatar, Foschini, and Gans	Claude Shannon
ประเภท	multicarrier modulation scheme	spatial multiplexing technique	fundamental theoretical bound
แหล่งต้นตำรับ	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.	Telatar, I. (1999). Capacity of multi-antenna Gaussian channels. European Transactions on Telecommunications, 10(6), 585-595.	Shannon, C. E. (1948). A mathematical theory of communication. Bell System Technical Journal, 27(3), 379-423.
ชื่อเรียกอื่น	multicarrier modulation	spatial multiplexing, antenna diversity	channel capacity, information theory bound
ที่เกี่ยวข้อง	5	5	5
สรุป	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.	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.	Shannon's channel capacity theorem, published in 1948, establishes the maximum rate at which information can be reliably transmitted over a noisy channel. Expressed as C = B log2(1 + S/N) for additive white Gaussian noise (AWGN), it is a fundamental bound in information theory and communications engineering. Shannon proved that reliable communication is possible at any rate below capacity, and impossible above it. This theorem underpins the design of all modern communication systems and motivates coding theory, modulation, and signal processing techniques.