Method of transmitting channel information in multiple antenna system
A method of transmitting channel information in a multiple antenna system includes receiving the channel information comprising rank information, and transmitting a confirm message through a downlink control channel as a confirmation for the channel information, wherein the confirm message comprises overriding rank information which overrides the received rank information in an open loop scheme and also comprises information indicating whether the received channel information is used without alteration in a closed loop scheme. A rank indicator (RI) and a precoding matrix indicator (PMI) can be carried on a dedicated control channel (DCCH) and be specified through a physical downlink control channel (PDCCH).
1. A method of transmitting channel information in a multiple antenna system, the method comprising:
transmitting a higher layer signal indicating whether a scheme in use is an open loop scheme or a closed loop scheme;
receiving channel information comprising rank information; and
transmitting a confirm message through a physical downlink control channel (PDCCH) as a response for the channel information,
wherein the confirm message has a fixed bit size irrespective of which scheme is used and a value of the confirm message indicates different information according to the higher layer signal,
wherein when the higher layer signal indicates an open loop scheme, the value of the confirm message indicates overriding rank information which overrides the received rank information, and
when the higher layer signal indicates a closed loop scheme, the value of the confirm message indicates information informing whether the received channel information is used without alteration or information informing assignment of a dedicated control channel comprised in a physical downlink shared channel (PDSCH), wherein the dedicated control channel is used for transmitting of an override message to specify a rank information.
2. The method of claim 1 , wherein the channel information further comprises precoding matrix index (PMI) information, and the confirm message comprises information indicating that the received PMI information is used without alteration in the closed loop scheme.
3. The method of claim 1 , wherein the channel information further comprises precoding matrix index (PMI) information, and the confirm message comprises information indicating that, instead of using the received PMI information, PMI information received in a previous period is used in the closed loop scheme.
4. The method of claim 1 , wherein the channel information further comprises precoding matrix index (PMI) information, and the confirm message comprises information indicating that a default PMI is used in the closed loop scheme.
5. The method of claim 1 , further comprising:
transmitting an override message through the dedicated control channel to specify a rank information when the value of the confirm message indicates the information informing assignment of the dedicated control channel.
6. An apparatus to transmit channel information in a multiple antenna system, the apparatus comprising:
a plurality of transmission antennas; and
a processor coupled to the plurality of transmission antennas and configured for:
transmitting a higher layer signal indicating whether a scheme in use is an open loop scheme or a closed loop scheme;
receiving the channel information comprising rank information; and
transmitting a confirm message through a physical downlink control channel (PDCCH) as a response for the channel information,
wherein the confirm message has a fixed bit size irrespective of which scheme is used and a value of the confirm message indicates different information according to the higher layer signal,
wherein when the higher layer signal indicates an open loop scheme, the value of the confirm message indicates overriding rank information which overrides the received rank information, and
when the higher layer signal indicates a closed loop scheme, the value of the confirm message indicates information informing whether the received channel information is used without alteration or information informing assignment of a dedicated control channel comprised in a physical downlink shared channel (PDSCH), wherein the dedicated control channel is used for transmitting of an override message to specify a rank information.