Feedback schemes in angular domain processing for MIMO antenna systems

Bunge, Brian

Permalink

https://hdl.handle.net/2142/29443 Copy

Description

Title

Feedback schemes in angular domain processing for MIMO antenna systems

Author(s)

Bunge, Brian

Issue Date

2012-02-01T00:46:39Z

Director of Research (if dissertation) or Advisor (if thesis)

Poon, Ada S.

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• multiple receive antenna (MIMO)
• Angular Domain
• Feedback
• Wireless

Abstract

Multiple transmit and multiple receive antenna (MIMO) systems provide an additional spatial dimension that yields a degree of freedom gain. The degree of freedom gain in MIMO systems allows for spatial multiplexing of multiple data streams onto the channel and an increase in the channel’s capacity or improved reliability against multipath fading. An MIMO antenna system with Nt transmit antennas and Nr receive antennas, under suitable fading conditions will yield a min(Nt,Nr) degree of freedom gain. This min(Nt,Nr) degree of freedom gain can be employed by spatial multiplexing multiple data streams to increase the channel’s capacity by a factor of min(Nt,Nr). In addition, the transmit signal at the transmit antenna array can be aligned in the direction of the transmit antenna array pattern so that the received signals add constructively at the receive antenna array. This transmit beamforming will provide a power gain in addition to the MIMO degree of freedom gain. However, in order to do transmit beamforming, the transmit antenna array must have knowledge of the channel’s state. Channel feedback in the conventional statistical MIMO channel is burdensome, due to the need to feed back information on each of the NrNt channel coefficients. The angular domain provides a much more natural, compact representation of the MIMO wireless channel than does the conventional model. In the angular domain, the transmit and receive arrays are divided into Nt and Nr respective resolvable angles, and the angular domain channel model examines the channel between the transmit and receive angular cells. The angular domain approach takes advantage of the physical nature of the wireless channel and produces a sparse channel matrix, unlike the previous conventional statistical model. As a result, less information will need to be fed back to the transmitter. This thesis applies array processing techniques to the MIMO wireless channel modeled in the angular domain to demonstrate the reduced computation complexity and feedback rate of angular domain processing.

Graduation Semester

2011-12

Permalink

http://hdl.handle.net/2142/29443

Copyright and License Information

Copyright 2011 Brian Bunge

Owning Collections