Blast is a wireless communication technique that exploits multipath scattering to improve data rates in multiple-input multiple-output (MIMO) systems. It was developed by Bell Labs and proposes a layered space-time architecture using space-time coding. The key types of Blast are D-Blast and V-Blast, which employ diagonal and vertical layering respectively to transmit independent data streams simultaneously. Blast aims to enhance capacity and transmission accuracy for applications like wireless internet access.

1. BLAST
(BELL LABORATRIES
LAYERED SPACE TIME)
GUIDE: Mr. ARUN T
KOKILA A V
S8, ECE A
NCAJEEC061
ECE DEPARTMENT 1

2. ABSTRACT
• Wireless communication technique
• Exploits multipath using scattering
characteristics
• Offer spatial multiplexing over multiple antenna
system
• improve spatial multiplexing gain provided by
MIMO systems.
• Developed by GERARD FOSCHINI
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3. CONTENTS
• KEYWORDS
• INTRODECTION
• BACKGROUND
• SPACE TIME CODING
• LAYERED SPACE TIME CODIND
• BELL LABS LAYERED SPACE TIME
• TYPES OF BLAST
• D-BLAST
• V-BLAST
• ADVANTAGES
• DISADVANTAGES
• CONCLUSION
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3

4. KEYWORDS
• MIMO: MULTIPLE INPUT OUTPUT
• STC: SPACE-TIME CODING
• LST: LAYERED SPACE-TIME CODING
• BLAST: BELL LABS LAYERED SPACE TIME
• D-BLAST: DIGONALLY LAYERED BLAST
• V-BLAST: VERTICAL BLAST
• RLST: RANDOM LAYERED SPACE-TIME
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5. INTRODUCTION
• Demand for wireless internet access rise rapidly
• MIMO systems have been extensively used in
wireless communication
• Space-time layered architectures offer a big increase
in capacity
• A layered space time architecture was proposed by
bell labs and labeled as BLAST
ECE DEPARTMENT 5

6. BACKGROUND
• SPACE-TIME CODING(STC)
Current transmission scheme over MIMO channels
•Data rate maximization
•Diversity maximization
STC aimed at realizing joint encoding across
MIMO channels
Number of code symbols equal to number of
transmit antennas
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7. BACKGROUND
LAYERED SPACE-TIME CODING(LST)
• Limitation of MIMO channel using STC
• LST was designed to improve the multiplexing gain by
transmitting nT independent data streams
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8. BLAST
• Layered space architecture proposed by bell labs
• Developed by Dr. G.J Foschini
• Efficient manner to enhance capacity
• Transmission accuracy
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9. TYPRES OF BLAST
• D-BLAST: Diagonally layered architecture
• V-BLAST: Vertical BLAST
• Turbo-BLAST
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10. D-BLAST
• Original scheme in BLAST family
• Diagonally layered coding sequence
• Input data streams divided to several substreams
• STC aimed at realizing joint encoding across MIMO
channels
• Number of code symbols equal to number of
transmit antennas
• Substreams are coded independently
• Decoder proceeds to decode one layer after another
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11. V-BLAST
• Simplified version of D-BLAST
• Layering is horizontal
OVERVIEW TO V-BLAST SYSTEM
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12. OVERVIEW OF BLAST SYSTEM
• Single data streams is demultiplexed to M
substreams
• Independent bit-to-bit symbol l mapping
• Decoder needs to demodulate the symbols
• Scheme is also known as vector modulation
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13. Turbo-BLAST
• Turbo-BLAST is a multitransmit multireceive (MTMR)
antenna scheme for high-throughput wireless
communications.
• Random layered space coding scheme (RLST)
• spectral efficiency attained in the course of two to
four iterations of the receiver
• Built-in capability of accommodating the multiple-
antenna configuration
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14. APPLICATION
• Wireless radio communication system
• Wireless internet access
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15. SCOPE OF DEVELOPMENT
• Unitary space modulation for fast fading
mobile environment
• Can make the effect of channel fading
effective
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16. ADVANTAGES
 Entire sub streams are transmitted in the same
frequency band.
 Spectrally efficiency.
 Total radiated power is held constant irrespective of
the number of transmitting antennas.
 The combined use of transmit and receive arrays
improve the data rate.
 With BLAST downloading a song would take 3s only.
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17. DISADVANTAGES
• It would require manufacture to invest in the
development of new multi-antenna devices.
• Require new wireless network infrastructure.
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18. CONCLUSION
• Improves the MIMO channels capacity
• It would require manufacture to invest in the
development of new multi-antenna devices.
• Require new wireless network infrastructure.
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19. REFERENCES
• www.bell-labs.com
• IEEE article 2010
• Communication and network, may2011
(www.scrip.org/journal/cn)
• hochwald@research.bell-labs.com
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20. ECE DEPARTMENT 20