Patent ID: 8792585
Filing Date: 2014-07-29
Classification: H04B,H04L

Abstract:
1. A rank estimation device, which estimates a transmission rank which is most suitable for data transmission based on a received signal at a receiver and reports the transmission rank to a transmitter as feedback information which is reflected to signal transmission in the transmitter, comprising: a first calculation unit for calculating a reception quality value based on the received signal; a second calculation unit for calculating a channel variation value which indicates a degree of variation of channel state based on the received signal; a first rank estimation unit for estimating the transmission rank based on a calculation value obtained by subtracting the reception quality value from the channel variation value; and a second rank estimation unit for calculating communication capacity between the transmitter and the receiver for all the transmission ranks and estimating the transmission rank which can obtain the maximum communication capacity, wherein the first rank estimation unit outputs a rank 1 of the transmission rank indicating a poor reception condition when the calculation value is greater than a first threshold value specified for determining the rank 1 in advance as a first condition, outputs a rank 2 of the transmission rank indicating a good reception condition when the calculation value is smaller than a second threshold value specified for determining the rank 2 in advance as a second condition, and outputs error information when the calculation value satisfies neither of the first condition nor the second condition, and wherein the second rank estimation unit is used when the error information is outputted from the first rank estimation unit to estimate the transmission rank.