A method used in a wireless communication apparatus based on reference signals, comprising: obtaining a plurality of pilot rules; obtaining radio channel information of a radio channel between the wireless communication apparatus and another wireless communication apparatus in an area including at least one cell and using one or more data streams; selecting applicable pilot rules from the plurality of pilot rules based on the radio channel information; creating at least one pilot structure to be used in the radio channel; and using the created at least one pilot structure to transmit data over the radio channel, wherein the plurality of pilot rules include: deleting a last OFDM symbol from a first resource unit including data symbols and pilot symbols to form pilot symbols for a second resource unit; duplicating a first OFDM symbol of the first resource unit and inserting an extra OFDM symbol behind the first resource unit to form pilot symbols for a third resource unit; and keeping a same pilot density for the first resource unit, the second resource unit, and the third resource unit to reduce power fluctuation, wherein, optionally: the first resource unit is an 18x6 resource unit; the second resource unit is an 18x5 resource unit; and the third resource unit is an 18x7 resource unit. obtaining a plurality of pilot rules; obtaining radio channel information of a radio channel between the wireless communication apparatus and another wireless communication apparatus in an area including at least one cell and using one or more data streams; selecting applicable pilot rules from the plurality of pilot rules based on the radio channel information; creating at least one pilot structure to be used in the radio channel; and using the created at least one pilot structure to transmit data over the radio channel, wherein the plurality of pilot rules include: deleting a last OFDM symbol from a first resource unit including data symbols and pilot symbols to form pilot symbols for a second resource unit; duplicating a first OFDM symbol of the first resource unit and inserting an extra OFDM symbol behind the first resource unit to form pilot symbols for a third resource unit; and keeping a same pilot density for the first resource unit, the second resource unit, and the third resource unit to reduce power fluctuation, wherein, optionally: the first resource unit is an 18x6 resource unit; the second resource unit is an 18x5 resource unit; and the third resource unit is an 18x7 resource unit. deleting a last OFDM symbol from a first resource unit including data symbols and pilot symbols to form pilot symbols for a second resource unit; duplicating a first OFDM symbol of the first resource unit and inserting an extra OFDM symbol behind the first resource unit to form pilot symbols for a third resource unit; and keeping a same pilot density for the first resource unit, the second resource unit, and the third resource unit to reduce power fluctuation, wherein, optionally: the first resource unit is an 18x6 resource unit; the second resource unit is an 18x5 resource unit; and the third resource unit is an 18x7 resource unit. the first resource unit is an 18x6 resource unit; the second resource unit is an 18x5 resource unit; and the third resource unit is an 18x7 resource unit. <EOS>