Method and apparatus for measurement reporting in carrier aggregation wireless communication systems
When detecting occurrence of an event for transmitting a measurement report of a radio condition of a cell at a frequency set for a base station apparatus, to the base station apparatus ( 3 ) communicating with a terminal apparatus ( 2 ), the terminal apparatus ( 2 ) in a wireless communication system ( 1 ) creates a measurement report including information indicating radio conditions of cells at a frequency at which the event occurred and at another different frequency. The base station apparatus ( 3 ) controls whether or not to perform handover of the terminal apparatus ( 2 ) to another cell, on the basis of the measurement report transmitted from the terminal apparatus ( 2 ). Thereby, there is provided a wireless communication system in which a base station apparatus and the terminal apparatus are communicable with each other using multiple frequencies, the wireless communication system being capable of shortening time required for handover.
1. A terminal apparatus comprising:
a transceiver, which, in operation, communicates with a base station; and
processing circuitry coupled to the transceiver, wherein the processing circuitry, in operation,
detects occurrences of an event in a cell, among multiple cells including serving cells and non-serving cells, wherein the serving cells are aggregately used by the transceiver to communicate with the base station on serving frequencies, and the non-serving cells are not presently used by the transceiver to communicate with the base station;
measures radio conditions of the serving cells and the non-serving cells; and
selects the best non-serving cell from the non-serving cells based on reference signal received power (RSRP) on one of the serving frequencies;
in response to detection of an occurrence of the event, creates a measurement report including radio conditions of the selected best non-serving cell;
wherein the transceiver, in operation, transmits the measurement report to the base station.
2. The terminal apparatus according to the claim 1 ,
wherein the measurement report includes a list of the best non-serving cells in order of decreasing RSRP.
3. The terminal apparatus according to claim 1 , which includes a policy set for identifying the multiple cells including the serving cells and the non-serving cells, for which radio conditions are measured.
4. The terminal apparatus according to claim 1 ,
wherein the best non-serving cell is a cell determined to have a higher RSRP than a reference RSRP.
5. The terminal apparatus according to claim 1 ,
wherein the measurement report includes radio conditions of the serving cells on the serving frequencies.
6. The terminal apparatus according to claim 5 ,
wherein the radio conditions of the serving cells and the radio conditions of the best non-serving cell are combined in one measurement report.
7. The terminal apparatus according to claim 1 ,
wherein the serving frequencies include a primary frequency and a secondary frequency, and
wherein the processing circuitry, in operation, determines whether to include in the measurement report: a) radio conditions of a cell on the primary frequency, or b) radio conditions of a cell on the primary frequency and of a cell on the secondary frequency.
8. A wireless communication method performed by a terminal apparatus, the method comprising:
detecting occurrences of an event in a cell, among multiple cells including serving cells and non-serving cells, wherein the serving cells are aggregately used to communicate with a base station on serving frequencies, and the non-serving cells are not presently used to communicate with the base station;
measuring radio conditions of the serving cells and the non-serving cells;
selecting the best non-serving cell from the non-serving cells based on reference signal received power (RSRP) on one of the serving frequencies;
in response to detection of an occurrence of the event, creating a measurement report including radio conditions of the selected best non-serving cell; and
transmitting the measurement report to the base station.
9. The method according to the claim 8 ,
wherein the measurement report includes a list of the best non-serving cells in order of decreasing RSRP.
10. The method according to claim 8 ,
wherein the terminal apparatus includes a policy set for identifying the multiple cells including the serving cells and the non-serving cells, for which radio conditions are measured.
11. The method according to claim 8 ,
wherein the best non-serving cell is a cell determined to have a higher RSRP than a reference RSRP.
12. The method according to claim 8 ,
wherein the measurement report includes radio conditions of the serving cells on the serving frequencies.
13. The method according to claim 12 ,
wherein the radio conditions of the serving cells and the radio conditions of the best non-serving cell are combined in one measurement report.
14. The method according to claim 8 ,
wherein the serving frequencies include a primary frequency and a secondary frequency, and
wherein the method further comprises determining whether to include in the measurement report: a) radio conditions of a cell on the primary frequency, or b) radio conditions of a cell on the primary frequency and of a cell on the secondary frequency.