View source for Edholm's law

{{short description|Law predicting that bandwidth and data rates double every 18 months}}
'''Edholm's law''', proposed by and named after Phil Edholm, refers to the observation that the three categories of [[telecommunication]],<ref name="Cherry">{{cite journal |last1=Cherry |first1=Steven |title=Edholm's law of bandwidth |journal=IEEE Spectrum |date=2004 |volume=41 |issue=7 |pages=58–60 |doi=10.1109/MSPEC.2004.1309810|s2cid=27580722 }}</ref> namely [[wireless]] (mobile), nomadic (wireless without mobility) and wired [[Telecommunications network|networks]] (fixed), are in lockstep and gradually converging.<ref name=":0">{{Cite book|title=Broadband Wireless Communications Business: An Introduction to the Costs and Benefits of New Technologies|url=https://archive.org/details/broadbandwireles00esma|url-access=limited|last=Esmailzadeh|first=Riaz|publisher=John Wiley & Sons, Ltd.|year=2007|isbn=9780470013113|location=West Sussex|pages=[https://archive.org/details/broadbandwireles00esma/page/n38 10]}}</ref> Edholm's law also holds that [[data rates]] for these telecommunications categories increase on similar exponential curves, with the slower rates trailing the faster ones by a predictable time lag.<ref>{{Cite book|title=Wireless Communications: The Future|last=Webb|first=William|publisher=John Wiley & Sons, Ltd.|year=2007|isbn=9780470033128|location=Hoboken, NJ|pages=67}}</ref> Edholm's law predicts that the [[bandwidth (computing)|bandwidth]] and data rates double every 18 months, which has proven to be true since the 1970s.<ref name="Cherry"/><ref name=":1">{{Cite book|title=Time Multiplexed Beam-Forming with Space-Frequency Transformation|last1=Deng|first1=Wei|last2=Mahmoudi|first2=Reza|last3=van Roermund|first3=Arthur|publisher=Springer|year=2012|isbn=9781461450450|location=New York|pages=1}}</ref> The trend is evident in the cases of [[Internet]],<ref name="Cherry"/> [[cellular network|cellular]] (mobile), [[wireless LAN]] and [[Personal area network|wireless personal area networks]].<ref name=":1" />

==Concept==
Edholm's law was proposed by Phil Edholm of [[Nortel Networks]]. He observed that telecommunication [[Bandwidth (signal processing)|bandwidth]] (including [[Internet access]] bandwidth) was doubling every 18 months, since the late 1970s through to the early 2000s. This is similar to [[Moore's law]], which predicts an exponential rate of growth for [[transistor]] [[transistor count|counts]]. He also found that there was a gradual convergence between wired (e.g. [[Ethernet]]), nomadic (e.g. [[modem]] and [[Wi-Fi]]) and [[wireless networks]] (e.g. [[cellular networks]]). The name "Edholm's law" was coined by his colleague, John H. Yoakum, who presented it at a 2004 [[Internet telephony]] press conference.<ref name="Cherry"/>

Slower communications channels like [[Mobile phone|cellphones]] and [[radio modem]]s were predicted to eclipse the capacity of early [[Ethernet]], due to developments in the standards known as [[UMTS]] and [[MIMO]], which boosted bandwidth by maximizing antenna usage.<ref name="Cherry"/> Extrapolating forward indicates a convergence between the rates of nomadic and wireless technologies around 2030. In addition, wireless technology could end wireline communication if the cost of the latter's infrastructure remains high.<ref name=":0" />

==Underlying factors==
In 2009, Renuka P. Jindal observed the bandwidths of online [[communication networks]] rising from [[bits per second]] to [[terabit per second|terabits per second]], doubling every 18 months, as predicted by Edholm's law. Jindal identified the following three major underlying factors that have enabled the exponential growth of communication bandwidth.<ref name="Jindal">{{cite book |last1=Jindal |first1=Renuka P. |title=2009 2nd International Workshop on Electron Devices and Semiconductor Technology |chapter=From millibits to terabits per second and beyond - over 60 years of innovation |date=2009 |pages=1–6 |doi=10.1109/EDST.2009.5166093 |chapter-url=https://events.vtools.ieee.org/m/195547|isbn=978-1-4244-3831-0 |s2cid=25112828 }}</ref>

*The [[MOSFET]] was invented at [[Bell Labs]] between 1955 and 1960, after Frosch and Derick discovered and used surface passivation by silicon dioxide to create the first planar transistors, the first in which drain and source were adjacent at the same surface.<ref>{{Cite patent|number=US2802760A|title=Oxidation of semiconductive surfaces for controlled diffusion|gdate=1957-08-13|invent1=Lincoln|invent2=Frosch|inventor1-first=Derick|inventor2-first=Carl J.|url=https://patents.google.com/patent/US2802760A}}</ref><ref>{{Cite journal |last1=Frosch |first1=C. J. |last2=Derick |first2=L |date=1957 |title=Surface Protection and Selective Masking during Diffusion in Silicon |url=https://iopscience.iop.org/article/10.1149/1.2428650 |journal=Journal of the Electrochemical Society |language=en |volume=104 |issue=9 |pages=547 |doi=10.1149/1.2428650|url-access=subscription }}</ref><ref>{{Cite book |last=Lojek |first=Bo |title=History of Semiconductor Engineering |date=2007 |publisher=Springer-Verlag Berlin Heidelberg |isbn=978-3-540-34258-8 |location=Berlin, Heidelberg |page=321}}</ref><ref>{{Cite journal |last1=Ligenza |first1=J.R. |last2=Spitzer |first2=W.G. |date=1960 |title=The mechanisms for silicon oxidation in steam and oxygen |url=https://linkinghub.elsevier.com/retrieve/pii/0022369760902195 |journal=Journal of Physics and Chemistry of Solids |language=en |volume=14 |pages=131–136 |doi=10.1016/0022-3697(60)90219-5|bibcode=1960JPCS...14..131L |url-access=subscription }}</ref><ref name="Lojek120223">{{cite book |last1=Lojek |first1=Bo |title=History of Semiconductor Engineering |date=2007 |publisher=[[Springer Science & Business Media]] |isbn=9783540342588 |page=120}}</ref> Advances in MOSFET technology (MOS technology) has been the most important contributing factor in the rapid rise of bandwidth in telecommunications networks. Continuous [[MOSFET scaling]], along with various advances in MOS technology, has enabled both [[Moore's law]] ([[transistor count]]s in [[integrated circuit]] chips doubling every two years) and Edholm's law (communication bandwidth doubling every 18 months).<ref name="Jindal" />
*[[Laser]] lightwave systems {{ndash}} The laser was demonstrated by [[Charles H. Townes]] and [[Arthur Leonard Schawlow]] at Bell Labs in 1960. Laser technology was later adopted in the design of integrated [[electronics]] using MOS technology, leading to the development of lightwave systems around 1980. This has led to exponential growth of bandwidth since the early 1980s.<ref name="Jindal"/>
*[[Information theory]] {{ndash}} Information theory, as enunciated by [[Claude Shannon]] at Bell Labs in 1948, provided a theoretical foundation to understand the trade-offs between [[signal-to-noise ratio]], [[Bandwidth (computing)|bandwidth]], and error-free [[Transmission (telecommunications)|transmission]] in the presence of [[noise]], in [[telecommunications]] technology. In the early 1980s, Renuka Jindal at Bell Labs used information theory to study the noise behaviour of MOS devices, improving their noise performance and resolving issues that limited their receiver sensitivity and data rates. This led to a significant improvement in the noise performance of MOS technology, and contributed to the wide adoption of MOS technology in lightwave and then [[wireless]] terminal applications.<ref name="Jindal"/>

The bandwidths of [[wireless networks]] have been increasing at a faster pace compared to wired networks.<ref name="Cherry"/> This is due to advances in MOSFET wireless technology enabling the development and growth of digital wireless networks. The wide adoption of [[RF CMOS]] ([[radio frequency]] [[CMOS]]), [[power MOSFET]] and [[LDMOS]] (lateral diffused MOS) devices led to the development and proliferation of digital wireless networks by the 1990s, with further advances in MOSFET technology leading to rapidly increasing [[Bandwidth (computing)|bandwidth]] since the 2000s.<ref name="Baliga">{{cite book |last1=Baliga |first1=B. Jayant |author1-link=B. Jayant Baliga |title=Silicon RF Power MOSFETS |date=2005 |publisher=[[World Scientific]] |isbn=9789812561213 |url=https://books.google.com/books?id=StJpDQAAQBAJ}}</ref><ref name="Asif">{{cite book |last1=Asif |first1=Saad |title=5G Mobile Communications: Concepts and Technologies |date=2018 |publisher=[[CRC Press]] |isbn=9780429881343 |pages=128–134 |url=https://books.google.com/books?id=yg1mDwAAQBAJ&pg=PT128}}</ref><ref name="O'Neill">{{cite journal |last1=O'Neill |first1=A. |title=Asad Abidi Recognized for Work in RF-CMOS |journal=IEEE Solid-State Circuits Society Newsletter |date=2008 |volume=13 |issue=1 |pages=57–58 |doi=10.1109/N-SSC.2008.4785694 |issn=1098-4232}}</ref> Most of the essential elements of wireless networks are built from MOSFETs, including the mobile [[transceiver]]s, [[base station]] modules, [[Router (computing)|routers]], [[RF power amplifier]]s,<ref name="Asif"/> [[telecommunication circuit]]s,<ref name="Colinge2016">{{cite book |last1=Colinge |first1=Jean-Pierre |last2=Greer |first2=James C.|title=Nanowire Transistors: Physics of Devices and Materials in One Dimension |date=2016 |publisher=[[Cambridge University Press]] |isbn=9781107052406 |page=2 |url=https://books.google.com/books?id=FvjUCwAAQBAJ&pg=PA2}}</ref> [[RF circuit]]s, and [[radio transceiver]]s,<ref name="O'Neill"/> in networks such as [[2G]], [[3G]],<ref name="Baliga"/> [[4G]], and [[5G]].<ref name="Asif"/>

In recent years, another enabling factor in the growth of [[wireless]] [[communication networks]] has been [[Interference (communication)|interference]] alignment, which was discovered by [[Syed Ali Jafar]] at the [[University of California, Irvine]].<ref name="Blavatnik">{{cite news |title=2015 National Laureates |url=http://blavatnikawards.org/news/items/2015-national-laureates/ |access-date=22 September 2019 |work=[[Blavatnik Awards for Young Scientists]] |date=June 30, 2015}}</ref> He established it as a general principle, along with Viveck R. Cadambe, in 2008. They introduced "a mechanism to align an arbitrarily large number of interferers, leading to the surprising conclusion that [[wireless networks]] are not essentially interference limited." This led to the adoption of interference alignment in the design of wireless networks.<ref>{{cite journal |last1=Jafar |first1=Syed A. |title=Interference Alignment — A New Look at Signal Dimensions in a Communication Network |journal=Foundations and Trends in Communications and Information Theory |date=2010 |volume=7 |issue=1 |pages=1–134 |doi=10.1561/0100000047 |citeseerx=10.1.1.707.6314 }}</ref> According to [[New York University]] senior researcher Dr. Paul Horn, this "revolutionized our understanding of the capacity limits of wireless networks" and "demonstrated the astounding result that each user in a wireless network can access half of the spectrum without interference from other users, regardless of how many users are sharing the spectrum."<ref name="Blavatnik"/>

==See also==
*[[History of the Internet]]
*[[History of telecommunication]]
*[[Internet access]]
*[[Internet traffic]]
*[[Moore's law]]
*[[Telecommunications]]
*[[Nielsen's law]]

==References==
<References/>

==Bibliography==
* {{cite journal |last1=Cherry |first1=Steven |title=Edholm's law of bandwidth |journal=IEEE Spectrum |date=2004 |volume=41 |issue=7 |pages=58–60 |doi=10.1109/MSPEC.2004.1309810|s2cid=27580722 }}

{{DEFAULTSORT:Edholm's Law}}
[[Category:Adages]]
[[Category:Computing culture]]
[[Category:Computer architecture statements]]
[[Category:Computer industry]]
[[Category:MOSFETs]]