A practical method for wireless channel reciprocity exploitation through relative calibration

We present a relative calibration method for a wireless TDD link, which, after a calibration phase involving feedback, lets the transmitter acquire knowledge of the downlink channel state from the uplink channel estimates, through proper modeling and estimation of the RF circuitry impulse responses. Contrarily to previous methods, relative calibration does not require specific calibration hardware. Experimental results confirm the validity of the proposed linear reciprocity model, and of the calibration approach.