Patent ID: 8305942
Filing Date: 2012-11-06
Classification: H04L

Abstract:
1. A Multiple-Input, Multiple Output (MIMO) wireless communication method comprising: transmitting precoded MIMO signals at least from a transmitter to a receiver; estimating the Eigen coherence bandwidth of a MIMO channel on the basis of a root mean square (r.m.s.) delay spread (T adjusting one or more precoding parameters used in said transmitter on the basis of said Eigen coherence bandwidth, prior to repeating the transmitting, wherein the method is a closed-loop Frequency Division Duplex (FDD) wireless communication method in which the estimating is performed in the receiver, and the receiver provides feedback signals to the transmitter including a value (K) indicative of the Eigen coherence bandwidth, the transmitter transmitting the MIMO signals on a plurality (L) of frequency fingers; the receiver detecting a channel gain and delay time for each of the L frequency fingers in a Single-Input Single Output (SISO) channel, and for each of a plurality of such SISO channels derived from the MIMO signals; and said estimating includes converting the channel response into the time domain to yield a channel gain and a delay time for each SISO channel, and calculating the average r.m.s, delay spread of the SISO channels from the channel gains and the delay times.