Abstract
Recently, Echo-MIMO, a delay-free feedback scheme has been proposed for Closed-Loop MIMO systems, where the receiver echoes the received signal on the fly to the transmitter without any processing. While this reduced feedback latency allows for more use of the channel’s coherence time for data transmission, it comes at high power-and-bandwidth costs, as two MIMO transmissions are required in the feedback phase. In this paper, we present a feedback scheme that preserves the advantages of Echo-MIMO while requiring only one feedback transmission. The echoed signals are judiciously combined with the receiver’s signals such that their separation at the transmitter be lossless, and that no extra transmit power nor bandwidth be required. In addition, we highlight the estimation accuracy degradation in Echo-MIMO owing to the echoed noise, and analytically confirm the intuition that removing the noise prior to echoing the received signal provides better estimation than echoing the noisy received signal as is and later account for the noise effect upon echo reception. Simulation results show that the proposed scheme outperforms Echo-MIMO in terms of channel estimation accuracy and achievable capacity.
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References
Telatar I. E. (1999) Capacity of multi-antenna Gaussian channels. European Transactions on Telecommunications 10(6): 585–595
Goldsmith, A. (eds) (2005) Wireless communications. Cambridge University Press, Cambridge
Tsuchiya Y., Ohtsuki T., Kaneko T. (2008) Scheduling algorithm with power allocation for random unitary beamforming. IEICE Transactions on Communications E91-B(1): 232–238
Hassibi B., Hochwald B. M. (2003) How much training is needed in multiple-antenna wireless links?. IEEE Transactions on Information Theory 49(4): 951–963
Love D. J., Heath R. W., Strohmer T. (2003) Grassmannian beamforming for multiple-input multiple-output wireless systems. IEEE Transactions on Information Theory 49(10): 2735–2747
Withers L. P., Taylor R. M., Warme D. M. (2008) Echo-MIMO: A two-way channel training method for matched cooperative beamforming. IEEE Transactions on Signal Processing 56(9): 4419–4432
Dent P., Bottomley G. E., Croft T. (1993) Jakes fading model revisited. IEEE Electronics Letters 29(13): 1162–1163
Ohno S., Giannakis G. B. (2002) Optimal training and redundant precoding for block transmissions with application to wireless OFDM. IEEE Transactions on Commununication 50(12): 2113–2123
Yoo T., Goldsmith A. (2006) Capacity and power allocation for fading MIMO channels with channel estimation error. IEEE Transactions on Information Theory 52(5): 2203–2214
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Souihli, O., Ohtsuki, T. Transparent Inband Feedback for Training-Based MIMO Systems. Wireless Pers Commun 63, 587–599 (2012). https://doi.org/10.1007/s11277-010-0152-z
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DOI: https://doi.org/10.1007/s11277-010-0152-z