
{"publication_number": "US-9025692-B2", "abstract": "a method implemented in a user terminal is disclosed . the method comprises obtaining known precoding matrix p of rank r and modulation and coding scheme assignments used in an original transmission , and a desired retransmission rank r \u2032, forming an approximate channel covariance matrix , estimating a minimum mean square error receiver sinr for each layer to be retransmitted responsive to said forming , and finding a retransmission precoding matrix from a preceding codebook that maximizes a sum - rate for enabling precoding selections for retransmissions in uplink multiple - input multiple - output mimo hybrid automatic repeat request harq . other methods , apparatuses , and systems also are disclosed .", "application_number": "US-201414247643-A", "description": "the present invention is directed to the problem of precoding selections at the user terminal for retransmitting one or multiple codewords in non - adaptive hybrid arq for uplink ( ul ) mimo when the transmission rank or number of codewords in the retransmissions is smaller than the corresponding value in the original transmission . particularly , this problem analysis considers that only imperfect channel state information ( csi ), e . g ., quantized channel information , is available at the user terminal . the block diagram of fig1 shows the inventive precoding selection for non - adaptive harq retransmission for ul mimo with imperfect / partial channel information . initially , 101 , the user terminal knows the precoding matrix p of rank r and the mcs assignments used in original transmission , as well as the desired retransmission rank r \u2032. based on these inputs we obtain the precoder for the retransmission of one codeword . following the input step 101 , the method 102 forms an approximate channel covariance matrix { circumflex over ( r )