Method and apparatus using cell-specific and common pilot subcarriers in multi-carrier, multi-cell wireless communication networks

In a cell within a group of cells in an orthogonal frequency division multiplexing system, a base station having multiple transmission branches, the base station comprising:

• a first transmitter component that is configured to transmit cell-specific pilot subcarriers, in accordance with a transmission diversity scheme or a multiple-input multiple-output scheme, wherein some of the cell-specific pilot subcarriers are not aligned in frequency subcarrier index with cell-specific pilot subcarriers transmitted by another base station in the group of cells;
• a second transmitter component that is configured to transmit common pilot subcarriers in accordance with a common pilot transmission scheme, wherein:
• the common pilot subcarriers are aligned in frequency subcarrier index with common pilot subcarriers transmitted by other base stations in the group of cells;
• a ratio of an amplitude (ai,m and an,m) of two common pilot subcarriers having a same time index (tk) that are transmitted via a common transmission branch is a constant for the group of cells;
• and
• a difference of a phase (φi,m and φn,m) of two common pilot subcarriers having a same time index (tk) that are transmitted via a common transmission branch is a constant for the group of cells;
• and
• a controller component that is configured to control independently a transmission power of the cell-specific pilot subcarriers and a transmission power of the common pilot subcarriers.