قارن الطرق

	تضمين التردد بتقسيم التعامد (OFDM)	تقنية الإدخال المتعدد والإخراج المتعدد (MIMO)	الترميز التوربيني مع فك التشفير التكراري
المجال	الاتصالات	الاتصالات	الاتصالات
العائلة	Process / pipeline	Process / pipeline	Process / pipeline
سنة النشأة	1971	1995	1993
صاحب الطريقة	Weinstein and Ebert	Telatar, Foschini, and Gans	Claude Berrou, Alain Glavieux, and Punya Thitimajshima
النوع	multicarrier modulation scheme	spatial multiplexing technique	iterative error-correcting code
المصدر التأسيسي	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.	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.
الأسماء البديلة	multicarrier modulation	spatial multiplexing, antenna diversity	iterative decoding, concatenated codes
ذات صلة	5	5	5
الملخص	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.	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.