OFDM Archives - GaussianWaves https://www.gaussianwaves.com/category/ofdm/ Signal Processing for Communication Systems Tue, 18 Jul 2023 07:13:39 +0000 en-US hourly 1 https://wordpress.org/?v=6.7.2 https://i0.wp.com/www.gaussianwaves.com/gaussianwaves/wp-content/uploads/2016/02/cropped-gaussianwaves_logo_120_120.png?fit=32%2C32&ssl=1 OFDM Archives - GaussianWaves https://www.gaussianwaves.com/category/ofdm/ 32 32 163393712 Orthogonality of OFDM https://www.gaussianwaves.com/2022/06/orthogonality-of-ofdm/ https://www.gaussianwaves.com/2022/06/orthogonality-of-ofdm/#respond Thu, 02 Jun 2022 04:02:00 +0000 https://www.gaussianwaves.com/?p=37646 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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]]> https://www.gaussianwaves.com/2022/06/orthogonality-of-ofdm/feed/ 0 37646 Cyclic Prefix in OFDM: hands-on demo in Matlab https://www.gaussianwaves.com/2016/05/ofdm_and_cyclic_prefix_a_handson_demonstration/ https://www.gaussianwaves.com/2016/05/ofdm_and_cyclic_prefix_a_handson_demonstration/#comments Thu, 26 May 2016 16:22:11 +0000 http://www.gaussianwaves.com/?p=12282 Synopsis: Cyclic prefix in OFDM, tricks a natural channel to perform circular convolution. This simplifies equalizer design at the receiver. Hands-on demo in Matlab. Cyclic Prefix-ed OFDM A cyclic-prefixed OFDM (CP-OFDM) transceiver architecture is typically implemented using inverse discrete Fourier transform (IDFT) and discrete Fourier transform (DFT) blocks (refer Figure 13.3). In an OFDM transmitter, ... Read more

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]]> https://www.gaussianwaves.com/2016/05/ofdm_and_cyclic_prefix_a_handson_demonstration/feed/ 19 12282 Breaking the Bandwidth Barrier – Li-Fi turns LED bulbs into High Speed Internet Hotspots https://www.gaussianwaves.com/2013/11/breaking-the-bandwidth-barrier-li-fi-turns-led-bulbs-into-high-speed-internet-hotspots/ https://www.gaussianwaves.com/2013/11/breaking-the-bandwidth-barrier-li-fi-turns-led-bulbs-into-high-speed-internet-hotspots/#respond Mon, 25 Nov 2013 09:20:00 +0000 http://www.gaussianwaves.com/?p=4137 Researchers, working on Ultra-Parallel Visible Light Communications (UP-VLC) project, have demonstrated 3.5Gpbs free space data transmission via three separate micro-LEDs that emit red, blue and green colours.  In effect, combining the three colours (that makes up for white colour), researchers say that achieving data rates over 10Gbps is feasible. The technology enabler here is called ... Read more

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]]> https://www.gaussianwaves.com/2013/11/breaking-the-bandwidth-barrier-li-fi-turns-led-bulbs-into-high-speed-internet-hotspots/feed/ 0 4137 OFDM simulation – performance in AWGN channel https://www.gaussianwaves.com/2011/07/simulation-of-ofdm-system-in-matlab-ber-vs-ebn0-for-ofdm-in-awgn-channel/ https://www.gaussianwaves.com/2011/07/simulation-of-ofdm-system-in-matlab-ber-vs-ebn0-for-ofdm-in-awgn-channel/#comments Fri, 08 Jul 2011 10:16:00 +0000 http://www.gaussianwaves.com/2011/07/simulation-of-ofdm-system-in-matlab-ber-vs-ebn0-for-ofdm-in-awgn-channel/ 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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]]> https://www.gaussianwaves.com/2011/07/simulation-of-ofdm-system-in-matlab-ber-vs-ebn0-for-ofdm-in-awgn-channel/feed/ 92 1690 Introduction to OFDM – orthogonal Frequency division multiplexing – part 4 – Cyclic Prefix https://www.gaussianwaves.com/2011/07/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-4-cyclic-prefix/ https://www.gaussianwaves.com/2011/07/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-4-cyclic-prefix/#comments Wed, 06 Jul 2011 07:06:00 +0000 http://www.gaussianwaves.com/2011/07/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-4-cyclic-prefix/ 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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]]> https://www.gaussianwaves.com/2011/07/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-4-cyclic-prefix/feed/ 7 1691 Introduction to OFDM – orthogonal Frequency division multiplexing – part 3 https://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-3/ https://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-3/#comments Mon, 27 Jun 2011 10:03:00 +0000 http://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-3/ 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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]]> https://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-3/feed/ 26 1692 Introduction to OFDM – orthogonal Frequency division multiplexing – part 2 https://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-2/ https://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-2/#comments Wed, 08 Jun 2011 10:09:00 +0000 http://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-2/ 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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]]> https://www.gaussianwaves.com/2011/06/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-part-2/feed/ 7 1693 Introduction to OFDM – orthogonal Frequency division multiplexing https://www.gaussianwaves.com/2011/05/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-2/ https://www.gaussianwaves.com/2011/05/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-2/#comments Tue, 24 May 2011 07:00:00 +0000 http://www.gaussianwaves.com/2011/05/introduction-to-ofdm-orthogonal-frequency-division-multiplexing-2/ 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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