Hamid Jafarkhani
Encyclopedia
Hamid Jafarkhani born in 1966 in Tehran
, is a Chancellor's Professor
in electrical engineering
and computer science
at the University of California, Irvine
's Henry Samueli School of Engineering
. His research focuses on communications
theory, particularly coding and wireless
communications and networks
.
Prior to studying at the University of Tehran
, he was ranked first in the nationwide entrance examination of Iran
ian universities
in 1984. After receiving his B.S.
degree
in 1989, he studied at the University of Maryland College Park and obtained his M.S.
degree in 1994 followed by his Ph.D.
in 1997. After graduating, Jafarkhani joined AT&T
Laboratories-Research in August 1997 before moving to Broadcom
in July 2000 and to the University of California, Irvine
in September 2001.
Within the wireless communications field, Jafarkhani is best known for his contributions to two seminal papers which established the field of space–time block coding
, published whilst working for AT&T. The first of these, "Space–time block codes from orthogonal designs", established the theoretical basis for space–time block codes and the second, "Space–time block coding for wireless communications: performance results", provided numerical analysis of the performance of the first such codes. Space–time code
s rely on the use of multiple antenna
s at the transmit side of a wireless link. Multiple copies of the same data are transmitted from these multiple antennas in such a way that the receiver has a much better chance of correctly detecting the signal in the presence of corruption and noise than if just one copy is sent. The performance of space–time coded systems, in terms of the reliability of the transmission is significantly better than non-coded systems. Space–time block codes in particular are known to be simple to implement and effective, and Jafarkhani's two papers triggered the massive international research effort into them that continues today.
Later, in 2001, Jafarkhani introduced quasi-orthogonal space–time block codes which overcome some of the difficulties inherent in earlier codes, at a cost of transmitting less data. These too are now widely studied. Then, in 2003 he introduced a more powerful version of his original codes, the super-orthogonal space–time trellis codes which combine the effects of both block codes and space–time trellis code
s. Again, this work has led to significant research efforts around the world.
Jafarkhani received a National Science Foundation
CAREER award in January 2003 which "recognizes outstanding scientists and engineers who, early in their careers, show exceptional potential for leadership at the frontiers of knowledge". He is also a Fellow of the Institute of Electrical and Electronics Engineers
(IEEE), an editor of IEEE Transactions on Wireless Communications
and an associate editor of IEEE Communications Letters
. Jafarkhani is the author of "Space-Time Coding: Theory and Practice", published in September 2005.
Tehran
Tehran , sometimes spelled Teheran, is the capital of Iran and Tehran Province. With an estimated population of 8,429,807; it is also Iran's largest urban area and city, one of the largest cities in Western Asia, and is the world's 19th largest city.In the 20th century, Tehran was subject to...
, is a Chancellor's Professor
Professor
A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...
in electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
and computer science
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...
at the University of California, Irvine
University of California, Irvine
The University of California, Irvine , founded in 1965, is one of the ten campuses of the University of California, located in Irvine, California, USA...
's Henry Samueli School of Engineering
Henry Samueli School of Engineering
The Henry Samueli School of Engineering is the academic unit of the University of California, Irvine that oversees academic research and teaching in various disciplines of the field of engineering...
. His research focuses on communications
Information transfer
In telecommunications, information transfer is the process of moving messages containing user information from a source to a sink.Note: The information transfer rate may or may not be equal to the transmission modulation rate.-See also:...
theory, particularly coding and wireless
Wireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
communications and networks
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
.
Prior to studying at the University of Tehran
University of Tehran
The University of Tehran , also known as Tehran University and UT, is Iran's oldest university. Located in Tehran, the university is among the most prestigious in the country, and is consistently selected as the first choice of many applicants in the annual nationwide entrance exam for top Iranian...
, he was ranked first in the nationwide entrance examination of Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
ian universities
University
A university is an institution of higher education and research, which grants academic degrees in a variety of subjects. A university is an organisation that provides both undergraduate education and postgraduate education...
in 1984. After receiving his B.S.
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...
degree
Academic degree
An academic degree is a position and title within a college or university that is usually awarded in recognition of the recipient having either satisfactorily completed a prescribed course of study or having conducted a scholarly endeavour deemed worthy of his or her admission to the degree...
in 1989, he studied at the University of Maryland College Park and obtained his M.S.
Master of Science
A Master of Science is a postgraduate academic master's degree awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.-Brazil, Argentina and Uruguay:...
degree in 1994 followed by his Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
in 1997. After graduating, Jafarkhani joined AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
Laboratories-Research in August 1997 before moving to Broadcom
Broadcom
Broadcom Corporation is a fabless semiconductor company in the wireless and broadband communication business. The company is headquartered in Irvine, California, USA. Broadcom was founded by a professor-student pair Henry Samueli and Henry T. Nicholas III from the University of California, Los...
in July 2000 and to the University of California, Irvine
University of California, Irvine
The University of California, Irvine , founded in 1965, is one of the ten campuses of the University of California, located in Irvine, California, USA...
in September 2001.
Within the wireless communications field, Jafarkhani is best known for his contributions to two seminal papers which established the field of space–time block coding
Space–time block code
Space–time block coding is a technique used in wireless communications to transmit multiple copies of a data stream across a number of antennas and to exploit the various received versions of the data to improve the reliability of data-transfer...
, published whilst working for AT&T. The first of these, "Space–time block codes from orthogonal designs", established the theoretical basis for space–time block codes and the second, "Space–time block coding for wireless communications: performance results", provided numerical analysis of the performance of the first such codes. Space–time code
Space–time code
A space–time code is a method employed to improve the reliability of data transmission in wireless communication systems using multiple transmit antennas...
s rely on the use of multiple antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
s at the transmit side of a wireless link. Multiple copies of the same data are transmitted from these multiple antennas in such a way that the receiver has a much better chance of correctly detecting the signal in the presence of corruption and noise than if just one copy is sent. The performance of space–time coded systems, in terms of the reliability of the transmission is significantly better than non-coded systems. Space–time block codes in particular are known to be simple to implement and effective, and Jafarkhani's two papers triggered the massive international research effort into them that continues today.
Later, in 2001, Jafarkhani introduced quasi-orthogonal space–time block codes which overcome some of the difficulties inherent in earlier codes, at a cost of transmitting less data. These too are now widely studied. Then, in 2003 he introduced a more powerful version of his original codes, the super-orthogonal space–time trellis codes which combine the effects of both block codes and space–time trellis code
Space–time trellis code
Space–time trellis codes are a type of space–time code used in multiple-antenna wireless communications. This scheme transmits multiple, redundant copies of a trellis code distributed over time and a number of antennas . These multiple, 'diverse' copies of the data are used by the receiver to...
s. Again, this work has led to significant research efforts around the world.
Jafarkhani received a National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
CAREER award in January 2003 which "recognizes outstanding scientists and engineers who, early in their careers, show exceptional potential for leadership at the frontiers of knowledge". He is also a Fellow of the Institute of Electrical and Electronics Engineers
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers is a non-profit professional association headquartered in New York City that is dedicated to advancing technological innovation and excellence...
(IEEE), an editor of IEEE Transactions on Wireless Communications
IEEE Transactions on Wireless Communications
IEEE Transactions on Wireless Communications is published six times a year by the IEEE Communications Society and the IEEE Signal Processing Society. The journal accepts both practical and theoretical papers dealing with new techniques, concepts, experiments and applications concerning all areas of...
and an associate editor of IEEE Communications Letters
IEEE Communications Letters
IEEE Communications Letters is monthly journal published by the IEEE Communications Society. It allows researchers to read about the most current results and developments in communications technology by publishing seven to ten short contributions from every area of communications technology...
. Jafarkhani is the author of "Space-Time Coding: Theory and Practice", published in September 2005.