BEGIN:VCALENDAR VERSION:2.0 PRODID:IEEE vTools.Events//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:Europe/Stockholm BEGIN:DAYLIGHT DTSTART:20240331T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3 TZNAME:CEST END:DAYLIGHT BEGIN:STANDARD DTSTART:20241027T020000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 TZNAME:CET END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20240902T135537Z UID:8D02E964-C4D5-41AF-ACD6-EB95873A8A53 DTSTART;TZID=Europe/Stockholm:20240902T130000 DTEND;TZID=Europe/Stockholm:20240902T143000 DESCRIPTION:It is widely accepted that nonlinear effects is something that should be avoided in digital communications. There are two main reasons fo r this. The first one is that the theoretical analysis of the impact of a given nonlinear device is not simple. The second\, and more important\, is the nonlinear devices can lead to significant spectral widening effects a nd/or performance degradation. Since the signals associated to widely empl oyed techniques like OFDM (Orthogonal Frequency Division Multiplexing) and /or MIMO (Multi-Input\, Multi-Output) schemes can have very large envelope fluctuations and PAPR (Peak-to-Average Power Rate)\, they are prone to no nlinear distortion effects like the ones associated to quantizers and powe r amplifiers. For these reasons\, there has been a huge effort in the desi gn of quasi-linear amplifiers\, as well as techniques to reduce the PAPR o f digital signals.\n\nIt was recently shown that strong nonlinear distorti on effects do not necessarily mean performance degradation. This is due to the fact that the nonlinear distortion component has some information on the transmitted signals\, which can be employed to improve the performance . In fact\, the optimum maximum likelihood (ML) performance of nonlinear O FDM schemes can even be better than the performance of the corresponding l inear. However\, the complexity of optimum ML receivers is prohibitively h igh\, even for a moderate number of subcarriers\, which lead to the develo pment of practical\, sub-optimum receivers able to achieve the optimum per formance of nonlinear OFDM.\n\nIn the first part of this tutorial we make an overview on the common nonlinear characteristics that arise in digital communications\, as well as techniques for studying analytically the impac t of nonlinear effects on given signals\, with emphasis on the signals ass ociated OFDM techniques and MIMO schemes. Then we present some key results on the impact of nonlinear operations in the spectral occupation and perf ormance. In the second part of this tutorial we study the optimum performa nce of nonlinear OFDM and MIMO schemes\, showing the remarkable result tha t nonlinear techniques can have much better performance than the correspon ding linear ones\, as well as some practical receivers able to harvest the se potential nonlinear performance gains.\n\nCo-sponsored by: Chalmers Uni versity of Technology\n\nSpeaker(s): Prof. Rui Dinis\n\nRoom: E2 Room 2503 \, Fredrik Lamm\, Bldg: EDIT building floor 3\, Chalmers University of Tec hnology \, Hörsalsvägen 11\, Göteborg\, Vastra Gotalands lan\, Sweden\, 581 83 LOCATION:Room: E2 Room 2503\, Fredrik Lamm\, Bldg: EDIT building floor 3\, Chalmers University of Technology \, Hörsalsvägen 11\, Göteborg\, Vastr a Gotalands lan\, Sweden\, 581 83 ORGANIZER:henkw@chalmers.se SEQUENCE:55 SUMMARY:IEEE Joint VTS/ComSoc Distinguished Lecture: Prof. Rui Dinis\, Nonl inear effects in digital communications URL;VALUE=URI:https://events.vtools.ieee.org/m/431065 X-ALT-DESC:Description: <br /><div>\n<p>It is widely accepted that nonlinea r effects is something that should be avoided in digital communications. T here are two main reasons for this. The first one is that the theoretical analysis of the impact of a given nonlinear device is not simple. The seco nd\, and more important\, is the nonlinear devices can lead to significant spectral widening effects and/or performance degradation. Since the signa ls associated to widely employed techniques like OFDM (Orthogonal Frequenc y Division Multiplexing) and/or MIMO (Multi-Input\, Multi-Output) schemes can have very large envelope fluctuations and PAPR (Peak-to-Average Power Rate)\, they are prone to nonlinear distortion effects like the ones assoc iated to quantizers and power amplifiers. For these reasons\, there has be en a huge effort in the design of quasi-linear amplifiers\, as well as tec hniques to reduce the PAPR of digital signals.&nbsp\;</p>\n<p>It was recen tly shown that strong nonlinear distortion effects do not necessarily mean performance degradation. This is due to the fact that the nonlinear disto rtion component has some information on the transmitted signals\, which ca n be employed to improve the performance. In fact\, the optimum maximum li kelihood (ML) performance of nonlinear OFDM schemes can even be better tha n the performance of the corresponding linear. However\, the complexity of optimum ML receivers is prohibitively high\, even for a moderate number o f subcarriers\, which lead to the development of practical\, sub-optimum r eceivers able to achieve the optimum performance of nonlinear OFDM.</p>\n< p>In the first part of this tutorial we make an overview on the common non linear characteristics that arise in digital communications\, as well as t echniques for studying analytically the impact of nonlinear effects on giv en signals\, with emphasis on the signals associated OFDM techniques and M IMO schemes. Then we present some key results on the impact of nonlinear o perations in the spectral occupation and performance. In the second part o f this tutorial we study the optimum performance of nonlinear OFDM and MIM O schemes\, showing the remarkable result that nonlinear techniques can ha ve much better performance than the corresponding linear ones\, as well as some practical receivers able to harvest these potential nonlinear perfor mance gains.</p>\n</div> END:VEVENT END:VCALENDAR