Method and apparatus for transmitting and receiving signals in multi-cellular network

A method for transmitting a signal in a multi-cellular network, the method comprising:

• receiving, from users located in cells belonging to the multi-cellular network, feedback information indicating effective Inter-Cell Interference (ICI) channels reaching from other Base Stations (BSs) to users of a j-th cell, a channel matrix determined by users in the cells, and a receive beamforming matrix;
• determining a transmit precoding matrix for data streams to be transmitted to each user located in a j-th cell among the cells belonging to the multi-cellular network, using the feedback information;
• and
• transmitting a signal to users in the j-th cell using the transmit precoding matrix,
• wherein the effective ICI channels and the receive beamforming matrix are determined by reference to a number tj,i of effective ICI channels caused by each of other BSs, a number nj,i(s) of ICI channels aligned to each effective ICI channel, and information about the channel matrix,
• wherein the number tj,i of effective ICI channels caused by each of other BSs and the number nj,i(s) of ICI channels aligned to each of the effective ICI channels are determined from a number B of the cells and a number Kj of users in the j-th cell based on a total number Sj of effective ICI channels of the j-th cell, and
• wherein the total number Sj of effective ICI channels of the j-th cell is determined from the number B of cells and the number Kj of users in the j-th cell.

An apparatus for receiving a signal in a multi-cellular network, the apparatus comprising:

• a parameter generator for determining a total number Sj of effective Inter-Cell Interference (ICI) channels of a j-th cell to which a user belongs, from a number B of cells belonging to the multi-cellular network and a number Kj of users in the j-th cell, and determining a number tj,i of effective ICI channels caused by each of other Base Stations (BSs) and a number nj,i(s) of ICI channels aligned to each effective ICI channel based on the number B of cells and the total number Sj of effective ICI channels;
• a channel estimator for acquiring information about a channel matrix between users of the j-th cell and each BS, which is estimated based on reference signals transmitted from a BS of the j-th cell and other BSs;
• a receive beamforming matrix generator for determining effective ICI channels reaching from each of the other BSs to users of the j-th cell, and a receive beamforming matrix, by reference to tj,i, nj,i(s) and information about the channel matrix;
• and
• a feedback unit for transmitting feedback information indicating the channel matrix and the receive beamforming matrix to a BS of the j-th cell,
• wherein the determined receive beamforming matrix is used to receive a signal from a BS of the j-th cell.

An apparatus for transmitting a signal in a multi-cellular network, the apparatus comprising:

• a feedback collector for receiving, from users located in cells belonging to the multi-cellular network, feedback information indicating effective ICI channels reaching from other BSs to users of a j-th cell, a channel matrix determined by users in the cells, and a receive beamforming matrix;
• and
• a transmit precoding matrix generator for determining a transmit precoding matrix for data streams to be transmitted to each user located in the j-th cell among the cells belonging to the multi-cellular network, using the feedback information,
• wherein the transmit precoding matrix is used to transmit a signal to users in the j-th cell,
• wherein the effective ICI channels and the receive beamforming matrix are determined by reference to a number tj,i of effective ICI channels caused by each of other BSs, a number nj,i(s) of ICI channels aligned to each effective ICI channel, and information about the channel matrix,
• wherein the number tj,i of effective ICI channels caused by each of other BSs and the number nj,i(s) of ICI channels aligned to each of the effective ICI channels are determined from a number B of cells and a number Kj of users in the j-th cell based on a total number Sj of effective ICI channels of the j-th cell, and
• wherein the total number Sj of effective ICI channels of the j-th cell is determined from the number B of cells and the number Kj of users in the j-th cell.