Fundamental overview and simulation of MIMO systems for SpaceTime coding and Spatial Multiplexing

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Fundamental overview and simulation of MIMO
systems for Space-Time coding and Spatial
Multiplexing

• by
• Hoo-Jin Lee, Shailesh Patil and Raghu G. Raj

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MIMO Multiple Input Multiple Output

• Current wireless scenario
• Capacity constrained networks.
• Issues related to quality and coverage.
• MIMO increases capacity1
• MIMO uses independent channel fading and
  multipath propagation to increase capacity.
• No extra expensive bandwidth required !!

C log2(1 SNR)
It is dangerous to put limits on wireless
Marconi, 1932
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MIMO Multiple Input Multiple Output
C ? M log2(1 SNR)

• MIMO gives reliable communication23
• Multiple independent samples of the same signal
  at the receiver give rise to diversity.

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Project Overview

• Objective Study and simulate Space -Time codes
  and Spatial Multiplexing
• Space -Time coding To gain diversity
• Block Codes Alamouti 2 scheme, ensures
  transmit diversity of 2.
• Trellis Codes Tarokh 3 et. al. developed a
  class of trellis codes and gave a metric for code
  performance in terms of diversity.
• Spatial Multiplexing Multiplexing symbols to get
  capacity gain.

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Project Overview

• Three kind of receivers
• Maximum Likelihood Receiver Gives best error
  performance but computation complexity increases
  exponentially with the number of transmit
  antennas 4.
• Linear Receiver Degraded performance, but
  computationally simple. Two types, MMSE and ZF
  receiver 4.
• V-BLAST Uses successive interference
  cancellation, to give better performance 5.

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Approach

• Study and analyze the discussed techniques.
• Perform Monte Carlo simulations using LabView
  under Rayleigh flat fading channel conditions and
  assuming perfect channel state information to
  judge the performance.
• Justification We can benchmark with references
  and MIMO provides maximum gain under these
  conditions.

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Expected Outcomes and Initial Results

• Knowledge
• Introduction to basics of MIMO systems.
• Gain insight into various MIMO based techniques.
• Simulations
• Under different antenna configurations.
• Comparison with single antenna systems.
• Comparison of between different coding and
  spatial multiplexing receivers.
• Brief review of application of these techniques
  to future generation systems.
• Studied and simulated Alamouti scheme.

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Alamouti simulations
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References

• 1 Foschini, G. J. and Gans, M. J., On limits
  of wireless communications in a fading
  environment when using multiple antennas,
  Wireless Personal Communications, vol. 6, pp.
  311-335, 1998
• 2 Alamouti, S. M. (1998). A simple transmit
  diversity technique for wireless communications.
  Selected Areas in Communications, IEEE
  Journal,16(8)14511458
• 3 Tarokh, V., Jafarkhani, H. and Calderbank, A.
  R., Space-time block coding for wireless
  communications performance results, IEEE
  Journal of selected areas in Communications, Vol.
  17, No. 3, pp. 451-460, March 1999
• 4 D. A. Gore, R. W. Heath, Jr., and A. J.
  Paulraj, Performance Analysis of Spatial
  Multiplexing in Correlated Channels,'' submitted
  to Communications, IEEE Transactions March 2002
• 5 Foschini, G. J., Layered space-time
  architecture wireless communication in a fading
  environment when using multi-element antenna,
  Bell Labs Tech. J., pp. 41-59, Autumn 1996

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Thank You !!