เปรียบเทียบวิธี

	การแบ่งความถี่แบบออร์โธโกนอล (Orthogonal Frequency Division Multiplexing - OFDM)	ทฤษฎีความจุช่องสัญญาณของแชนนอน	การเข้ารหัสแบบเทอร์โบพร้อมการถอดรหัสแบบวนซ้ำ
สาขาวิชา	โทรคมนาคม	โทรคมนาคม	โทรคมนาคม
ตระกูล	Process / pipeline	Process / pipeline	Process / pipeline
ปีกำเนิด	1971	1948	1993
ผู้ริเริ่ม	Weinstein and Ebert	Claude Shannon	Claude Berrou, Alain Glavieux, and Punya Thitimajshima
ประเภท	multicarrier modulation scheme	fundamental theoretical bound	iterative error-correcting code
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.	Shannon, C. E. (1948). A mathematical theory of communication. Bell System Technical Journal, 27(3), 379-423.	Berrou, C., Glavieux, A., & Thitimajshima, P. (1993). Near Shannon limit error-correcting coding and decoding: Turbo-codes. In Proceedings of the IEEE International Conference on Communications (ICC), 1064-1070.
ชื่อเรียกอื่น	multicarrier modulation	channel capacity, information theory bound	iterative decoding, concatenated codes
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.	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.	Turbo codes, introduced by Berrou, Glavieux, and Thitimajshima in 1993, are a landmark in channel coding history. They achieve performance within 0.5 dB of the Shannon limit—the theoretical boundary for reliable communication—a feat previously thought impossible with practical complexity. Turbo codes use concatenated convolutional codes with an interleaver and iterative decoding via belief propagation. They were adopted in 3G (UMTS) and remain important in 4G/5G systems alongside LDPC codes.