Orthogonal Frequency Division Multiplexing Archives - GaussianWaves

Orthogonality of OFDM

Mathuranathan — Thu, 02 Jun 2022 04:02:00 +0000

OFDM, known as Orthogonal Frequency Division Multiplexing, is a digital modulation technique that divides a wideband signal into several narrowband signals. By doing so, it elongates the symbol duration of each narrowband signal compared to the original wideband signal, effectively minimizing the impact of time dispersion caused by multipath delay spread. OFDM is categorized as ... Read more

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OFDM simulation – performance in AWGN channel

Mathuranathan — Fri, 08 Jul 2011 10:16:00 +0000

Goal: Simulate discrete-time cyclic-prefixed OFDM communication system. Explain role of IFFT/FFT, cyclic prefix. Simulate M-QPSK / M-QAM based cyclic prefixed OFDM over AWGN channel. Discrete-time implementation of baseband CP-OFDM The schematic diagram of a simplified cyclic-prefixed OFDM (CP-OFDM) data transmission system is shown in Figure 1. The basic parameter to describe an OFDM system is ... Read more

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Introduction to OFDM – orthogonal Frequency division multiplexing – part 4 – Cyclic Prefix

Mathuranathan — Wed, 06 Jul 2011 07:06:00 +0000

Consider a non-ideal channel h(t)≠δ(t), that causes delay dispersion. Delay dispersion manifests itself as Inter Symbol Interference (ISI)on each subcarrier channel due to pulse overlapping. It will also cause ICC (Inter Carrier Interference ) due to the non-orthogonality of the received signal. Adding cyclic prefix to each OFDM symbol mitigates the problems of ISI and ... Read more

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Introduction to OFDM – orthogonal Frequency division multiplexing – part 3

Mathuranathan — Mon, 27 Jun 2011 10:03:00 +0000

In the previous article, the architecture of an OFDM transmitter was described using sinusoidal components. Generally, an OFDM signal can be represented as \(s(t)\) = symbols mapped to chosen constellation (BPSK/QPSK/QAM etc..,) \(f_n\) = orthogonal frequency This equation can be thought of as an IFFT process ( Inverse Fast Fourier Transform). The Fourier transform breaks a ... Read more

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Introduction to OFDM – orthogonal Frequency division multiplexing – part 2

Mathuranathan — Wed, 08 Jun 2011 10:09:00 +0000

Article moved to new pages The article has been consolidated into these following pages. Please refer these links. If you are looking for Matlab code refer this ebook : Simulation of Digital Communication Systems by Mathuranathan Viswanathan (1) Introduction to OFDM – Orthogonal Frequency Division Multiplexing (2) An OFDM Communication System – Implementation Details (3) ... Read more

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Introduction to OFDM – orthogonal Frequency division multiplexing

Mathuranathan — Tue, 24 May 2011 07:00:00 +0000

In modulations, information is mapped on to changes in frequency, phase or amplitude (or a combination of them) of a carrier signal. Multiplexing deals with allocation/accommodation of users in a given bandwidth (i.e. it deals with allocation of available resource).OFDM is a combination of modulation and multiplexing. In this technique, the given resource (bandwidth) is ... Read more

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