Time reversal techniques for wireless communications

The application of the time reversal (TR) technique in a multiple input-single output (MISO) configuration can reduce the delay spread of the channel impulse response by a factor of 2-3, depending on the power allocation scheme. Moreover, this technique provides a gain of about 20 dB in peak signal power. These effects are demonstrated with measurements of fixed wireless access channels in the 5 GHz band. The measurements were performed at 3 different locations in downtown Toronto, and the channel has been measured with 8 element uniform linear antenna arrays at both ends, thus providing an 8×8 configuration.