Bell Laboratories Layered Space-Time
Encyclopedia
Bell Laboratories Layered Space-Time (BLAST) is a transceiver
architecture for offering spatial multiplexing
over multiple-antenna wireless communication systems. Such systems have multiple antennas at both the transmitter and the receiver in an effort to exploit the many different paths between the two in a highly-scattering
wireless environment. BLAST was developed by Gerard Foschini at Lucent Technologies
' Bell Laboratories (now Alcatel-Lucent Bell Labs). By careful allocation of the data to be transmitted to the transmitting antenna
s, multiple data stream
s can be transmitted simultaneously within a single frequency band — the data capacity
of the system then grows directly in line with the number of antennas (subject to certain assumptions). This represents a significant advance on current, single-antenna systems.
to the receipt of multi-antenna MIMO
systems . Available for the first time in 1996 at Bell Laboratories in New Jersey in the United States by Gerard J. Foschini
. He proceeded simply to eliminate interference caused successively issuers.
Its principle is quite simple: to make a first detection of the most powerful signal. It regenerates the received signal from this user from this decision. Then, the signal is regenerated subtracted from the received signal and, with this new sign, it proceeds to the detection of the second user's most powerful, since it has already cleared the first and so forth. What gives a vector containing received less interference.
The complete detection algorithm can be summarized as recursive as follows:
Initialize:
Recursive:
Transceiver
A transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver. The term originated in the early 1920s...
architecture for offering spatial multiplexing
Spatial multiplexing
Spatial multiplexing is a transmission technique in MIMO wireless communication to transmit independent and separately encoded data signals, so-called streams, from each of the multiple transmit antennas...
over multiple-antenna wireless communication systems. Such systems have multiple antennas at both the transmitter and the receiver in an effort to exploit the many different paths between the two in a highly-scattering
Scattering
Scattering is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which they pass. In conventional use, this also includes deviation of...
wireless environment. BLAST was developed by Gerard Foschini at Lucent Technologies
Lucent Technologies
Alcatel-Lucent USA, Inc., originally Lucent Technologies, Inc. is a French-owned technology company composed of what was formerly AT&T Technologies, which included Western Electric and Bell Labs...
' Bell Laboratories (now Alcatel-Lucent Bell Labs). By careful allocation of the data to be transmitted to the transmitting 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, multiple data stream
Data stream
In telecommunications and computing, a data stream is a sequence of digitally encoded coherent signals used to transmit or receive information that is in the process of being transmitted....
s can be transmitted simultaneously within a single frequency band — the data capacity
Channel capacity
In electrical engineering, computer science and information theory, channel capacity is the tightest upper bound on the amount of information that can be reliably transmitted over a communications channel...
of the system then grows directly in line with the number of antennas (subject to certain assumptions). This represents a significant advance on current, single-antenna systems.
V-BLAST
V-BLAST (Vertical-Bell Laboratories Layered Space-Time) is a detection algorithmAlgorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
to the receipt of multi-antenna MIMO
MIMO
In radio, multiple-input and multiple-output, or MIMO , is the use of multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology...
systems . Available for the first time in 1996 at Bell Laboratories in New Jersey in the United States by Gerard J. Foschini
Gerard J. Foschini
Gerard Joseph Foschini , is an American telecommunications engineer who has worked for Bell Laboratories since 1961. His research has covered many kinds of data communications, particularly wireless communications and optical communications. Foschini has also worked on point-to-point systems and...
. He proceeded simply to eliminate interference caused successively issuers.
Its principle is quite simple: to make a first detection of the most powerful signal. It regenerates the received signal from this user from this decision. Then, the signal is regenerated subtracted from the received signal and, with this new sign, it proceeds to the detection of the second user's most powerful, since it has already cleared the first and so forth. What gives a vector containing received less interference.
The complete detection algorithm can be summarized as recursive as follows:
Initialize:
Recursive:
See also
- Space–time codeSpace–time codeA space–time code is a method employed to improve the reliability of data transmission in wireless communication systems using multiple transmit antennas...
— a means for using multiple antennas to improve reliability rather than data-rate. - TelecommunicationTelecommunicationTelecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...