Title of Invention

A METHOD OF SPATIAL MULTIPLEXING FOR HIGH DATA RATE WIRELESS COMMUNICATION

Abstract A method of spatial multiplexing for high data rate wireless communication comprising the steps of decomposing Ntx Nr MIMO channel into parallel eigen channels, interleaving co-ordinates of each pair of symbols that are to be transmitted over these channels; decoupling and de-interleaving the received signals before decoding the same.
Full Text

This invention relates to a method of spatial multiplexing for high data rate wireless communication.
The method of spatial multiplexing for high data rate wireless communication, according to this invention, comprises the steps of decomposing Multiple Input Multiple
Output (MIMO) channel into parallel eigen channels, interleaving co-ordinates of each pair of symbols that are to be transmitted over these channels; decoupling and de-interleaving the received signals, before decoding the same.
Over the last decade, MIMO communication technology has emerged as a promising candidate to achieve high data rates over time varying wireless fading channels. Information theoretic results show that MIMO systems can offer significant capacity gains over traditional Single Input Single Output (SISO) channels, at no extra cost of bandwidth and power.



Now, each of the received symbols contains information about only one transmitted symbol. Thus, the received symbols are decoupled and the receiver can employ simplest detection rule known as single-symbol maximum likelihood (ML) detection. This results in a huge saving of receiver complexity. Such single-symbol ML detectors for closed-loop spatial multiplexing are already available in the literature. For example, Geometric Mean Decomposition (GMD) precoding of Jiang et. al (IEEE Trans, on Signal Processing, 2005) tries to alleviate this problem. However, the performance of GMD precoding is poorer to ML, and moreover degrades for correlated and line-of-sight MIMO channels.
In any spatial multiplexing MIMO system, one of the eigen channel is very weak in that it has very low signal-to-noise ratio (SNR). Most of symbols transmitted on this channel will be decoded erroneously and this increases the overall error rate of the MIMO system.
Co-ordinate interleaving is used to improve the SNR of the weakest eigen channel.
The concept of co-ordinate interleaving (CI) is to interleave real and imaginary parts of the complex symbols to be transmitted over independent fading channels so that they encounter different fading channel gains. At the receiver, they are de-interleaved before decoding.

With channel knowledge at both ends, co-ordinate interleaving is applied across the symbols transmitted on different eigen modes. The method for a 2x2 MIMO system is described below by way of exemplification. This is self-explanatory of the extension of the description of any system.


For system, we need to feedback only a single angle for the proposed method
to work. This reduces the amount of feedback required, which can further be reduced
by quantizing the angle to be feedback.
The receiver complexity is low due to the fact that the receiver employs symbol-by-
symbol decoding, which turns out to be optimal for this method.
This method enables maximal spatial multiplexing to work well under several
channel conditions. This means that the proposed method can be used to send K =
min{ N,,N^} symbols simultaneously irrespective of whether the underlying channel
is uncorrelated Rayleigh faded, correlated Rayleigh faded or Ricean.



We Claim:
1 .A method of spatial multiplexing for high data rate wireless communication comprising the steps of decomposing Ntx Nr MIMO channel into parallel eigen channels, interleaving co-ordinates of each pair of symbols that are to be transmitted over these channels; decoupling and de-interleaving the received signals before decoding the same.
2. A method as claimed in Claim 1 wherein when min { Nt, N is odd one of streams will not be co-ordinate interleaved but transmitted unaltered.
3. A method of spatial multiplexing for high data rate wireless communication substantially as herein described with reference to, and as illustrated in the accompanying drawings.


Documents:

1720-CHE-2007 AMENDED CLAIMS 08-08-2012.pdf

1720-CHE-2007 AMENDED PAGES OF SPECIFICATION 08-08-2012.pdf

1720-CHE-2007 FORM-1 08-08-2012.pdf

1720-CHE-2007 POWER OF ATTORNEY 08-08-2012.pdf

1720-CHE-2007 POWER OF ATTORNEY 29-06-2012.pdf

1720-CHE-2007 POWER OF ATTORNEY.pdf

1720-CHE-2007 AMENDED PAGES OF SPECIFICATION 26-07-2012.pdf

1720-CHE-2007 CORRESPONDENCE OTHERS 29-06-2012.pdf

1720-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 08-08-2012.pdf

1720-CHE-2007 FORM-13 29-06-2012.pdf

1720-CHE-2007 POWER OF ATTORNEY 26-07-2012.pdf

1720-che-2007 claims.pdf

1720-CHE-2007 CORRESPONDENCE OTHERS 26-07-2012.pdf

1720-che-2007 correspondence others.pdf

1720-che-2007 description (complete).pdf

1720-che-2007 drawing.pdf

1720-che-2007 form-1.pdf

1720-che-2007 form-18.pdf

1720-che-2007 form-26.pdf

1720-che-2007-claims.pdf

1720-che-2007-correspondnece-others.pdf

1720-che-2007-description(complete).pdf

1720-che-2007-drawings.pdf

1720-che-2007-form 1.pdf

1720-che-2007-form 18.pdf

1720-che-2007-form 26.pdf


Patent Number 253683
Indian Patent Application Number 1720/CHE/2007
PG Journal Number 33/2012
Publication Date 17-Aug-2012
Grant Date 13-Aug-2012
Date of Filing 06-Aug-2007
Name of Patentee INDIAN INSTITUTE OF TECHNOLOGY Madras
Applicant Address IIT P.O CHENNAI 600 036
Inventors:
# Inventor's Name Inventor's Address
1 KOTHAPALLI VENKATA SRINIVAS JUNIOR SCIENTIST CEWIT IIT P.O CHENNAI 600 036
2 JENISTON DEVIRAJ KLUTTO MILLETH JUNIOR SCIENTIST CEWIT IIT P.O CHENNAI 600 036
3 RAVINDER DAVID KOILPILLAI PROFERROR DEPARTMENT OF ELECTRICAL ENGINEERING IIT CHENNAI 600 036
4 KRISHNAMURTHY GIRIDHAR PROFERROR DEPARTMENT OF ELECTRICAL ENGINEERING IIT CHENNAI 600 036
PCT International Classification Number H04J 11/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA