A method of transmitting a feedback message through a feedback header, the method comprising: receiving a feedback request message comprising a feedback type field; and transmitting the feedback header, wherein the feedback header has a format comprising the feedback type field and a feedback contents field as a response to the feedback request message wherein a value of the feedback type field indicates a type of information contained in the feedback contents field and the size of the feedback contents field is 16 bits or 32 bits; wherein when the value of the feedback type field indicates a closed-loop, CL, multiple input multiple output, MIMO, feedback, the feedback contents field comprises a CL MIMO type field and MIMO information, the CL MIMO type field indicating any one of an antenna grouping, an antenna selection, a codebook based feedback, and transition from CL MIMO to open-loop MIMO; the method being characterized in that: when the CL MIMO type field indicates the codebook based feedback, the MIMO information comprises N codebook indexes and N differential channel quality indicators, CQIs, wherein the N codebook indexes indicate codebooks used for N best subbands of M subbands according to CQI, where both M and N are a natural number and M is larger than N; wherein each of the N differential CQIs indicates a difference between a reference CQI and a CQI for each of the N best subbands; wherein each of the N codebook indexes comprises 3 bits and each of the N differential CQIs comprises 2 bits; and wherein the reference CQIs are transmitted before the feedback message is transmitted. receiving a feedback request message comprising a feedback type field; and transmitting the feedback header, wherein the feedback header has a format comprising the feedback type field and a feedback contents field as a response to the feedback request message wherein a value of the feedback type field indicates a type of information contained in the feedback contents field and the size of the feedback contents field is 16 bits or 32 bits; wherein when the value of the feedback type field indicates a closed-loop, CL, multiple input multiple output, MIMO, feedback, the feedback contents field comprises a CL MIMO type field and MIMO information, the CL MIMO type field indicating any one of an antenna grouping, an antenna selection, a codebook based feedback, and transition from CL MIMO to open-loop MIMO; the method being characterized in that: when the CL MIMO type field indicates the codebook based feedback, the MIMO information comprises N codebook indexes and N differential channel quality indicators, CQIs, wherein the N codebook indexes indicate codebooks used for N best subbands of M subbands according to CQI, where both M and N are a natural number and M is larger than N; wherein each of the N differential CQIs indicates a difference between a reference CQI and a CQI for each of the N best subbands; wherein each of the N codebook indexes comprises 3 bits and each of the N differential CQIs comprises 2 bits; and wherein the reference CQIs are transmitted before the feedback message is transmitted. when the CL MIMO type field indicates the codebook based feedback, the MIMO information comprises N codebook indexes and N differential channel quality indicators, CQIs, wherein the N codebook indexes indicate codebooks used for N best subbands of M subbands according to CQI, where both M and N are a natural number and M is larger than N; wherein each of the N differential CQIs indicates a difference between a reference CQI and a CQI for each of the N best subbands; wherein each of the N codebook indexes comprises 3 bits and each of the N differential CQIs comprises 2 bits; and wherein the reference CQIs are transmitted before the feedback message is transmitted.