NSF-ECCS #0621879: Efficient MIMO Transceivers Based on Channel Decomposition Techniques

Our current research under this project is carried on cooperatively by three research groups under the direction of Dr. Liuqing Yang and Dr. Jian Li at the University of Florida, and Dr. Gerald E. Sobelman at the University of Minnesota.

In the past, MIMO transceiver designs have always relied on the singular value decomposition (SVD) or QR decomposition to convert a MIMO channel into parallel scalar channels with vastly different gains. This either leads to the bit-loading strategy, or entails a persistent tradeoff between channel throughput and system error performance. To address such a tradeoff, Dr. Jian Li’s research group has developed transceiver designs by based on a novel geometric mean decomposition (GMD), which can be combined with either the conventional VBLAST decoder or the more recent zero-forcing dirty paper precoder (ZFDP) [12] [14]. Currently, our research team continues to establish the theory of flexible and robust MIMO transceiver design based on the new channel decomposition paradigm. More details…

In the mean time, to relax the limiting non-selective fading constraints, our team is also working on generalizing the theory to account for various channel fading conditions, and with different levels of channel state information. Recently, we also found that MIMO transceiver design techniques can be readily applied to enable seamless multiple access in heterogeneous networks. In [1], [11] and [13], our research group directed by Dr. Liuqing Yang has established a novel digital transceiver design concept for asymmetric ultra-wideband (or general broadband) communications links, which takes into account the unbalanced complexity of the transmitter and receiver due to differential analog-to-digital and digital-to-analog conversion rates. Theoretical analysis shows that the system input/output relationship resembles that of a MIMO system. This renders MIMO transceiver design readily applicable to the optimization of these asymmetric communications links. More details...

To prototype and test our algorithms, Dr. Gerald E. Sobelman’s research group works on the design of the low-power and high-performance digital VLSI circuits and systems. Recently, they have successfully realized a MIMO joint transceiver hardware platform based on a modified GMD on a Xilinx FPGA [7]. In addition, their research group has also successfully realized a digital hardware model for ultra-wideband channels on a Xilinx FPGA [8], and a complete pulsed-OFDM transceiver [10] which is an enhancement to the prevailing ultra-wideband technique. These works provide a hardware platform and test environment for the implementation of the GMD-based MIMO transceivers, and potential capacity-approaching ultra-wideband transceivers for heterogeneous networks. More details…

Publications

[1] H. Xu and L. Yang, “Low-Complexity Transceiver Design for Asymmetric Single/Multi-Band UWB Links,” IEEE Transactions on Wireless Communications, 2007 (submitted).

[2] F. Qu and L. Yang, “Orthogonal Space-Time Block-Differential Modulation over Underwater Acoustic Channels,” in Proceedings of MTS/IEEE Oceans, Vancouver, Canada, September 29-October 4, 2007 (submitted).

[3] X. Zheng, Y. Xie, J. Li, and P. Stoica, “MIMO Transmit Beamforming under Uniform Elemental Power Constraint,” IEEE Transactions on Signal Processing, 2007 (to appear).

[4] H. Xu and L. Yang, “Multi-Carrier Frequency-Differential UWB Radios,” IEEE Transactions on Signal Processing, 2007 (to appear).

[5] H. Xu and L. Yang, “Low-Complexity Transceiver Design for Asymmetric Single/Multi-Band UWB Links, ” in Proceedings of IEEE International Conference on Ultra-Wideband, Singapore, September 24-26, 2007 (to appear).

[6] X. Zheng, Y. Xie, J. Li, and P. Stoica, “MIMO Transmit Beamforming under Uniform Elemental Power Constraint,” in Proceedings of 2007 IEEE Workshop on Signal Processing Advances in Wireless Communications, Helsinki, Finland, June 17-20, 2007 (to appear).

[7] W. Kan and G. E. Sobelman, “MIMO Transceiver Design Based on a Modified Geometric Mean Decomposition,“ in Proceedings of ISCAS, New Orleans, LA, May 27-30, 2007.

[8] W. Kan and G. E. Sobelman, “Hardware Channel Model for Ultra Wideband Systems,” in Proceedings of IEEE International Conference on Field Programmable Technology, Bangkok, Thailand, December 13-15, 2006, pp. 297–300.

[9] X. Zheng, P. Stoica, J. Li, and R. Wu, “Adaptive Arrays for Broadband Communications in the Presence of Co-Channel Interference, ” in Proceedings of the 40th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, October 29-November 1, 2006, pp. 1032–1036.

[10] K. Chang and G. E. Sobelman, “FPGA-Based Design of a Pulsed-OFDM System,” in Proceedings of IEEE Asia Pacific Conference on Circuits and Systems, Singapore, Singapore, December 4-7, 2006, pp. 1130–1133.

[11] L. Yang, J. Li and Y. Jiang, “Capacity-Approaching Transceiver Design for Asymmetric UWB Links,” in Proceedings of the 39th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, October 30-November 2, 2005, pp. 151–155 (invited).

[12] Y. Jiang, J. Li, and W. W. Hager, “Joint Transceiver Design for MIMO Communications Using Geometric Mean Decomposition,” IEEE Transactions on Signal Processing, vol. 53, no. 10, pp. 3791–3803, Oct. 2005.

[13] L. Yang, “Rate-Scalable UWB for WPAN with Heterogeneous Nodes,” in Proceedings of IEEE International Conference on Acoustics, Speech and Signal Processing(ICASSP), Philadelphia, PA, March 19-23, 2005, vol. 3, pp. 625–628.

[14] Y. Jiang, W. W. Hager, and J. Li, “The geometric mean decomposition,” Linear Algebra Its Applications, vol. 396, pp. 373–384, Feb. 2005.

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This material is based upon work supported by the National Science Foundation under Grant No. 0621879. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.