Information feedback method for coordinated multipoint communication
Coordinated multipoint communication is a technology for improving cell-edge performance for users in a cell-type mobile communication system. In order to enable a coordinated multipoint transmission/reception operation, a user equipment report of a local environment is required to select both coordinated communication modes and communication partners in evolved Node B (eNB) base stations. According to the present invention, a method is described for feeding back information from User Equipment (UE) to a serving base station to enable a coordinated multi-point transmission/reception operation. The information reported through the feedback is classified into two categories corresponding to received signal intensity information and received signal timing information. The UE may select one or both types of information from between the categories to provide feedback. In embodiments of the present invention, various overhead-reducing reporting formats are described.
1. A feedback method of a terminal for supporting coordinated multipoint processing in a mobile communication system, the method comprising:
generating a measurement report message including delay information of a first signal received from a candidate transmission point and power allocation information for the candidate transmission point determined based on information on a received signal power corresponding to the first signal;
transmitting the measurement report message to a serving transmission point; and
receiving a second signal transmitted by a cooperative transmission point selected among the serving transmission point and the candidate transmission point, based on the measurement report message,
wherein the delay information comprises information on whether a delay per the received first signal from the candidate transmission point is greater than a threshold value,
wherein the threshold value is determined based on a cyclic prefix of the serving transmission point,
wherein the delay corresponding to the selected cooperative transmission point is less than the threshold value,
wherein the power allocation information is quantized based on information on a received signal power corresponding to the serving transmission point, and
wherein a boosting value of the quantized power allocation information is determined based on a transmission power of the serving transmission point.
2. The feedback method of claim 1 , wherein the measurement report message comprises signal strength information per signal received from at least one of the serving transmission point and the candidate transmission point.
3. The feedback method of claim 1 , wherein the delay information comprises the reception timing per received signal from the candidate transmission point.
4. A feedback method of a terminal for supporting coordinated multipoint processing in a mobile communication system, the method comprising:
generating a measurement report message including measurement of a channel quality of a serving transmission point and a candidate transmission point adjacent to the serving transmission point, wherein the channel quality comprises signal strength information per signal received from the serving transmission point and the candidate transmission point, and generating the measurement report message comprises:
creating the measurement report message by determining power allocation information to be recommended to the serving transmission point and the candidate transmission point according to received signal strengths, wherein the power allocation information is quantized based on the signal strength information per signal received from the serving transmission point;
transmitting the measurement report message to the serving transmission point; and
receiving a signal transmitted by a cooperative transmission point selected among the serving transmission point and the candidate transmission point, based on the measurement report message,
wherein a boosting value of the quantized power allocation information is determined based on a transmission power of the serving transmission point.
5. The feedback method of claim 4 , wherein generating the measurement report message comprises creating the measurement report message by processing the channel quality in binary format or quantizing the channel quality.
6. The feedback method of claim 4 , wherein generating the measurement report message comprises creating the measurement report message having precoding matrix indicators for the serving transmission point and the candidate transmission point.
7. The feedback method of claim 4 , further comprising checking the candidate transmission point from a candidate transmission point list transmitted by the serving transmission point.
8. A cooperation method of a transmission point for cooperative multipoint processing in a mobile communication system, the method comprising:
receiving a measurement report message from a terminal, the measurement report message including delay information of a first signal received by a terminal from a candidate transmission point and power allocation information for the candidate transmission point determined based on information on a received signal power corresponding to the first signal;
determining a cooperative transmission point among a serving transmission point and the candidate transmission point, based on the measurement report message;
transmitting a second signal to the terminal in cooperation with the cooperative transmission point;
wherein the delay information comprises information on whether a delay per the received first signal by the terminal, from the candidate transmission point, is greater than a threshold value, and
wherein the threshold value is determined based on a cyclic prefix of the serving transmission point,
wherein the delay corresponding to the selected cooperative transmission point is less than the threshold value,
wherein the power allocation information is quantized based on information on a received signal power corresponding to the serving transmission point, and
wherein a boosting value of the quantized power allocation information is determined based on a transmission power of the serving transmission point.
9. The cooperation method of claim 8 , wherein the measurement report message comprises signal strength information per signal received from at least one of the serving transmission point and the candidate transmission point.
10. The cooperation method of claim 8 , wherein the delay information comprises the reception timing per received signal from the candidate transmission point.
11. A cooperation method of a transmission point for cooperative multipoint processing in a mobile communication system, the method comprising:
determining a cooperative transmission point by analyzing channel quality of a candidate transmission point that is included in a measurement report message transmitted by a terminal, wherein the channel quality comprises signal strength information per signal received from a serving transmission point and the candidate transmission point and the terminal generates the measurement report message by determining power allocation information to be recommended to the serving transmission point and the candidate transmission point according to received signal strengths, and wherein the power allocation information is quantized based on the signal strength information per signal received from the serving transmission point; and
transmitting data to the terminal in cooperation with the cooperative transmission point,
wherein a boosting value of the quantized power allocation information is determined based on a transmission power of the serving transmission point.
12. The cooperation method of claim 11 , wherein the terminal generates the measurement report message by processing the channel quality in binary format or quantizing the channel quality.
13. The cooperation method of claim 11 , further comprising transmitting a list including the candidate transmission point for the terminal to measure the channel quality.