buffer 12 of transmitter 10 thus constituting a loop the loop will go on until the received new retransmission user data is correct then receiver 20 outputs the retransmission user data and feeds back an ack indicator respectively to harq combining unit 23 of receiver 20 and tx buffer 12 of transmitter 10 simultaneously the above weighted combining process can be realized according to the following formula r u2061 i u2211 i 0 n retrans u2062 u2062 s u2061 i snr_est u2062 i u03c3 snr u2061 i u2211 i 0 n retrans u2062 u2062 snr_est u2062 i u03c3 snr u2061 i snr_est u2062 i lt snr threshold u2062 u2062 and u2062 u2062 u03c3 snr u2061 i gt u03c3 threshold r u2061 i u2211 i 0 n retrans u2062 u2062 s u2061 i snr_est u2062 i u2211 i 0 n retrans u2062 snr_est u2062 i snr_est u2062 i u2265 snr threshold u2062 u2062 or u2062 u2062 u03c3 snr u2061 i u2264 u03c3 threshold n retrans indicates the retransmission times of a transmission block and 1 u2266 n retrans lt n max n max indicates the maximum retransmission times of a transmission block according to above detailed description of the embodiment the harq hybrid automatic repeat requests combining.