transmitted through an ofdm symbol in the subframe the srs is a reference signal transmitted for ul scheduling from a ue to a bs the bs estimates a ul channel through the received srs and uses the estimated ul channel in ul scheduling the reference signal implies the dm rs and or the srs hereinafter an ofdm symbol for data transmission is referred to as a data symbol an ofdm symbol for dm rs transmission is referred to as a dm rs symbol and an ofdm symbol for srs transmission is referred to as an srs symbol a reference signal symbol implies the dm rs symbol and or the srs symbol in fig6 there are 12 data symbols and 2 dm rs symbols in one subframe in fig7 there are 10 data symbols and 2 dm rs symbols in one subframe fig8 is a block diagram showing an exemplary structure of a transmitter herein the transmitter may be a part of a ue or a bs referring to fig8 a transmitter 100 includes a data processor 110 a reference signal processor 120 and a radio frequency rf unit 130 the rf unit 130 is coupled to the data processor 110 and the reference signal processor 120 the data processor 110 processes data to generate a baseband signal for the data the reference signal processor 120 generates and processes a reference signal and generates a baseband signal for the reference signal the rf unit 130 converts the.