Optimal Pilot Spacing and Power in Rate-Adaptive MIMO Diversity Systems with Imperfect CSI

In this paper, performance of a rate-adaptive multiple-input multiple-output diversity system with imperfect channel state information is analyzed and optimized. Space-time block coding is utilized to exploit spatial diversity and to thereby combat some of the fading in wireless channel communications. The remaining fading is tacked by means of adaptive coded modulation. The pilot symbol period and the power allocated to pilot and data symbols are optimized in such a way that the average spectral efficiency is maximized. At the same time, the instantaneous (with respect to predicted channel-signal-to-noise ratio) bit error rate is maintained below a desired level. The average time duration that the channel stays within a certain interval, the average fade region duration, is also derived. A numerical example is given for uncorrelated flat Rayleigh fading subchannels with Jakes spectrum

[1]  G.E. Oien,et al.  Optimal pilot spacing and power in rate-adaptive MIMO diversity systems with imperfect transmitter CSI , 2005, IEEE 6th Workshop on Signal Processing Advances in Wireless Communications, 2005..

[2]  J. Cavers.  An analysis of pilot symbol assisted modulation for Rayleigh fading channels (mobile radio) , 1991 .

[3]  A. Robert Calderbank,et al.  Space-Time block codes from orthogonal designs , 1999, IEEE Trans. Inf. Theory.

[4]  Georgios B. Giannakis,et al.  Adaptive PSAM accounting for channel estimation and prediction errors , 2005, IEEE Transactions on Wireless Communications.

[5]  Kjell Jørgen Hole,et al.  Impact of channel prediction on adaptive coded modulation performance in Rayleigh fading , 2004, IEEE Transactions on Vehicular Technology.

[6]  Georgios B. Giannakis,et al.  Adaptive Modulation for multiantenna transmissions with channel mean feedback , 2004, IEEE Transactions on Wireless Communications.

[7]  Heinrich Meyr,et al.  Digital communication receivers - synchronization, channel estimation, and signal processing , 1997, Wiley series in telecommunications and signal processing.

[8]  Charles W. Therrien,et al.  Discrete Random Signals and Statistical Signal Processing , 1992 .

[9]  G.E. Oien,et al.  Limitations in spectral efficiency of a rate-adaptive MIMO system utilizing pilot-aided channel prediction , 2003, The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring..

[10]  Norman C. Beaulieu,et al.  Level crossing rate and average fade duration of MRC and EGC diversity in Ricean fading , 2003, IEEE Trans. Commun..

[11]  G.E. Oien,et al.  Adaptive coded modulation with receive antenna diversity and imperfect channel knowledge at receiver and transmitter , 2006, IEEE Transactions on Vehicular Technology.

[12]  Youngwook Ko,et al.  Optimal switching thresholds for space-time block coded rate-adaptive M-QAM , 2004, 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[13]  A. Goldsmith,et al.  Variable-rate variable-power MQAM for fading channels , 1996, Proceedings of Vehicular Technology Conference - VTC.

[14]  Georgios B. Giannakis,et al.  Optimal transmitter eigen-beamforming and space time block coding based on channel mean , 2002, 2002 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[15]  Youngwook Ko,et al.  Space-time block coded rate-adaptive modulation with uncertain SNR feedback , 2003, The Thrity-Seventh Asilomar Conference on Signals, Systems & Computers, 2003.

[16]  Siavash M. Alamouti,et al.  A simple transmit diversity technique for wireless communications , 1998, IEEE J. Sel. Areas Commun..

[17]  Georgios B. Giannakis,et al.  Adaptive modulation for multi-antenna transmissions with channel mean feedback , 2003, IEEE International Conference on Communications, 2003. ICC '03..

[18]  Georgios B. Giannakis,et al.  How accurate channel prediction needs to be for transmit-beamforming with adaptive modulation over Rayleigh MIMO channels? , 2004, IEEE Transactions on Wireless Communications.

[19]  Alexander M. Haimovich,et al.  On Pilot Symbol Aided Channel Estimation for Time Varying Rayleigh Fading Channels , 2004 .

[20]  Mohamed-Slim Alouini,et al.  Adaptive Modulation over Nakagami Fading Channels , 2000, Wirel. Pers. Commun..

[21]  I. S. Gradshteyn,et al.  Table of Integrals, Series, and Products , 1976 .

[22]  Andrea J. Goldsmith,et al.  Degrees of freedom in adaptive modulation: a unified view , 2001, IEEE Trans. Commun..

[23]  Kjell Jørgen Hole,et al.  Adaptive multidimensional coded modulation over flat fading channels , 2000, IEEE Journal on Selected Areas in Communications.

[24]  Arogyaswami Paulraj,et al.  Space-time block codes: a capacity perspective , 2000, IEEE Communications Letters.