Mobile station and reception quality measurement method
Received Signal Strength Indicator (RSSI) is measured accurately even in a case where a discovery signal is transmitted. A receiver receives a plurality of subframes, at least one of which includes a discovery signal, and a measurer measures Reference Signal Reception Power (RSRP) using a first resource in which the discovery signal is mapped, measures RSSI using a second resource different from the first resource for which the discovery signal is mapped, and calculates Reference Signal Reception Quality (RSRQ) using RSRP and RSSI.
1. A mobile station comprising:
a receiver that receives a plurality of subframes, at least one of which includes a discovery signal that is a signal transmitted from an OFF-state cell having no traffic data to be transmitted and is used by the mobile station to detect the OFF-state cell; and
measuring circuitry that is coupled to the receiver and that measures Reference Signal Reception Power (RSRP) using a first resource in which the discovery signal is mapped, measures Received Signal Strength Indicator (RSSI) using a second resource in which the discovery signal is not mapped, and calculates Reference Signal Reception Quality (RSRQ) using the RSRP and the RSSI.
2. The mobile station according to claim 1 , wherein the first resource is a first subframe and the second resource is a second subframe among the received plurality of subframes, and the measurer measures the RSSI in the second subframe that is different from the first subframe for which the RSRP is measured.
3. The mobile station according to claim 2 , wherein the measurer measures the RSSI using all of a plurality of symbols included in the second subframe.
4. The mobile station according to claim 2 , wherein the measurer measures the RSSI using symbols that include Cell specific Reference Signal (CRS), among a plurality of symbols included in the second subframe.
5. The mobile station according to claim 2 , wherein the second subframe is located adjacent to the first subframe.
6. The mobile station according to claim 1 , wherein the measurer measures the RSSI using symbols that are part of a plurality of symbols included in a subframe for which the RSSI is measured, wherein the symbols that are used to measure the RSSI are symbols other than a particular number of symbols in a first half portion or a second half portion of the subframe for which the RSSI is measured.
7. The mobile station according to claim 1 , wherein the resource is a subframe and the measurer measures the RSSI in the same subframe as the subframe for which the RSRP is measured.
8. The mobile station according to claim 1 , wherein the resource is a resource element (RE) and the measurer measures the RSSI using an RE other than any RE in which a discovery signal is mapped.
9. The mobile station according to claim 7 , wherein the measurer measures the RSSI using a symbol other than symbol(s) that includes a resource in which a discovery signal is mapped.
10. The mobile station according to claim 7 , wherein the measurer measures the RSSI using a symbol that includes a Cell specific Reference Signal (CRS), among symbols other than that include a resource in which the discovery signal is mapped.
11. A reception quality measurement method implemented in a mobile station, the method comprising:
receiving a discovery signal that is a signal transmitted from an OFF-state cell having no traffic data to be transmitted and is used by the mobile station to detect the OFF-state cell; and
measuring Reference Signal Reception Power (RSRP) using a resource in which the discovery signal is mapped, measuring Received Signal Strength Indicator (RSSI) using a resource in which the discovery signal is not mapped, and calculating Reference Signal Reception Quality (RSRQ) using the RSRP and the RSSI.
12. The mobile station according to claim 1 , wherein
the receiver receives discovery signal information that indicates a subframe in which the discovery signal is mapped;
the measuring circuit detects the indicated subframe as the first resource in which the discovery signal is mapped.
13. The mobile station according to claim 12 , wherein a plurality of discovery signals transmitted from a plurality of OFF-state cells are mapped in the indicated subframe.
14. The mobile station according to claim 12 , wherein no traffic data is mapped in the first resource and traffic data transmitted from an ON-state cell to the mobile station is mapped in the second resource.
15. The reception quality measurement method according to claim 11 , comprising
receiving discovery signal information that indicates a subframe in which the discovery signal is mapped;
detecting the indicated subframe as the first resource in which the discovery signal is mapped.
16. The reception quality measurement method according to claim 15 , wherein a plurality of discovery signals transmitted from a plurality of OFF-state cells are mapped in the indicated subframe.
17. The reception quality measurement method according to claim 15 , wherein no traffic data is mapped in the first resource and traffic data transmitted from an ON-state cell to the mobile station is mapped in the second resource.