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Node-to-node data transfer
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<h2 id="source-coding">Source coding</h2> <i>See main article <a href="/facts/Data_compression/gMFuY4FT">Data compression</a></i> <p>Source coding is the elimination of redundancy to make efficient use of storage space and/or transmission channels. </p><p>Examples of source coding are: </p> <ul><li><a href="/facts/Huffman_coding/dBgMBz48">Huffman coding</a></li> <li><a href="/facts/Morse_code/GXwCl1HV">Morse code</a></li> <li><a href="/facts/Binary_coding/v5YF0sQl">Binary coding</a></li></ul> <h2 id="channel-coding">Channel coding</h2> <i>See main article <a href="/facts/Error_correction_and_detection/o2rH8e3n">Error correction and detection</a>.</i> <p>In <a href="/facts/Digital_data/JChckAvr">digital</a> <a href="/facts/Telecommunications/vxoj1cxR">telecommunications</a>, channel coding<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> is a pre-transmission mapping applied to a <a href="/facts/Digital_signal_(signal_processing)/bCtTHxre">digital signal</a> or data file, usually designed to make error-correction (or at least <a href="/facts/Error-detecting_code/o2rH8e3n">error detection</a>) possible. </p><p>Error correction is implemented by using more <a href="/facts/Numerical_digit/JJdLBoGT">digits</a> (<a href="/facts/Bit/S972NSaD">bits</a> in cases of binary channel) than the number strictly necessary for the samples and having the receiver compute the most likely valid message that could have resulted in the received one. </p><p>Types of channel coding include: </p> <ul><li><a href="/facts/Parity_check/peFp3Wau">Parity checks</a></li> <li><a href="/facts/Hamming_code/zsI8cTRC">Hamming code</a></li> <li><a href="/facts/Reed-Muller_code/HUKw1xrV">Reed-Muller code</a></li> <li><a href="/facts/Reed-Solomon_code/HPc3Qj6N">Reed-Solomon code</a></li> <li><a href="/facts/Turbo_coding/F3nmelu0">Turbo coding</a></li></ul> <h2 id="line-coding">Line coding</h2> <i>See main article <a href="/facts/Line_code/x9IuaYNL">Line code</a></i> <p>Line coding consists of representing the <a href="/facts/Digital_signal_(electronics)/pKYKbxfK">digital signal</a> to be transported, by an amplitude- and time-discrete signal, that is optimally tuned for the specific properties of the physical channel (and of the receiving equipment). The <a href="/facts/Waveform/yAskMREw">waveform</a> pattern of voltage or current used to represent the 1s and 0s of a digital signal on a transmission link is called <i>line encoding</i>. After line coding, the signal can directly be put on a transmission line, in the form of variations of the current. The common types of line encoding are <a href="/facts/Unipolar_encoding/1yAVSv8T">unipolar</a>, <a href="/facts/Polar_encoding/8f3cfm9r">polar</a>, <a href="/facts/Bipolar_encoding/I84wDjmR">bipolar</a> and <a href="/facts/Manchester_encoding/0nb5SVmP">Manchester encoding</a>. </p><p>Line coding should make it possible for the receiver to synchronise itself to the <a href="/facts/Phase_(waves)/cpGtuVll">phase</a> of the received signal. It is also preferred for the line code to have a structure that will enable error detection. </p><p>Examples of line coding include: <i>(see main article <a href="/facts/Line_code/x9IuaYNL">line code</a>)</i> </p> <ul><li><a href="/facts/B8ZS/0XxtLVYs">B8ZS</a></li> <li><a href="/facts/HDB3/0XxtLVYs">HDB3</a></li> <li><a href="/facts/2B1Q/rC9KAydW">2B1Q</a></li> <li><a href="/facts/Alternate_Mark_Inversion/I84wDjmR">AMI</a></li> <li><a href="/facts/Gray_coding/HtbVlM7T">Gray coding</a></li></ul> <h2 id="modulation">Modulation</h2> <p class="note">Main article: <a href="/facts/Modulation/aAXPjINv">Modulation</a></p> <p>Modulation is the process of varying a <i><a href="/facts/Carrier_signal/ae98pBlY">carrier signal</a></i>, typically a <a href="/facts/Sine_wave/mD1CB09M">sine wave</a> to use that signal to convey <a href="/facts/Information/3LdrzXtJ">information</a>. One of the three key characteristics of a signal are usually modulated: its <a href="/facts/Phase_(waves)/cpGtuVll">phase</a>, <a href="/facts/Frequency/QUSbPaW8">frequency</a> or <a href="/facts/Amplitude/aEckuXJM">amplitude</a>. </p><p>In <a href="/facts/Digital_data/JChckAvr">digital</a> modulation, the changes in the signal are chosen from a fixed list (the modulation alphabet) each entry of which conveys a different possible piece of information (a symbol). In <a href="/facts/Analog_signal/xDbb4uB5">analogue</a> modulation, the change is applied continuously in response to the data signal. </p><p>Modulation is generally performed to overcome signal transmission issues such as to allow </p> <ul><li>Easy (low loss, low dispersion) <a href="/facts/Wave_propagation/PXhWIt7k">propagation</a> as <a href="/facts/Electromagnetic_wave/Ynx7ujCW">electromagnetic waves</a></li> <li><a href="/facts/Multiplexing/YE7hK8cw">Multiplexing</a>, the transmission of multiple data signals in one frequency band, on different <a href="/facts/Carrier_signal/ae98pBlY">carrier</a> frequencies.</li> <li>Smaller, more <a href="/facts/Directional_antenna/oLesxknQ">directional antennas</a></li></ul> <p>Carrier signals are usually high frequency electromagnetic waves. </p><p>Examples of modulation include: </p> <ul><li><a href="/facts/Amplitude_modulation/3sTxsXk6">amplitude modulation</a></li> <li><a href="/facts/Frequency_modulation/qIExDdtv">frequency modulation</a></li> <li><a href="/facts/Phase-shift_keying/TFnpYe64">Phase-shift keying</a></li></ul> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Communication_channel/MtlxEShV">Communication channel</a></li> <li><a href="/facts/Data_link/fSNk5Nus">Data link</a></li> <li><a href="/facts/Data_transmission/1yAhaANd">Data transmission</a></li> <li><a href="/facts/Point-to-point_(telecommunications)/RmGgN1Pj">Point-to-point (telecommunications)</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>"Node-to-Node Data Transfers". Intel. Retrieved 2022-07-22. <a href="https://www.intel.com/content/www/us/en/develop/documentation/application-snapshot-user-guide/top/detailed-analyses/mpi-analyses/analysis-charts/node-to-node-data-transfers.html" target="_blank">https://www.intel.com/content/www/us/en/develop/documentation/application-snapshot-user-guide/top/detailed-analyses/mpi-analyses/analysis-charts/node-to-node-data-transfers.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>"Information and Communication Theory Source Coding Techniques -PART -II Handbook on Source Coding Techniques -Part II". <a href="https://www.researchgate.net/publication/358285643" target="_blank">https://www.researchgate.net/publication/358285643</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Fanari, L.; Iradier, E.; Bilbao, I.; Cabrera, R.; Montalban, J.; Angueira, P. (2021). "Comparison between Different Channel Coding Techniques for IEEE 802.11be within Factory Automation Scenarios". Sensors (Basel, Switzerland). 21 (21): 7209. Bibcode:2021Senso..21.7209F. doi:10.3390/s21217209. PMC 8587646. PMID 34770516. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8587646" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8587646</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> </ol>