Communication apparatus and control signal mapping method
A communication apparatus includes a circuitry and a transmitter. In operation, the circuitry generates a Demodulation Reference Signal (DMRS) and generates downlink control information indicating a mapping pattern of the DMRS from a plurality of mapping patterns, and the transmitter transmits the DMRS and the downlink control information. The plurality of mapping patterns includes a first mapping pattern and a second mapping pattern. Resource elements used for the DMRS of the second mapping pattern are same as a part of resource elements used for the DMRS of the first mapping pattern. A number of the resource elements used for the DMRS of the first mapping pattern is larger than a number of the resource elements used for the DMRS of the second mapping pattern.
1. A communication apparatus comprising:
a circuitry, which, in operation, generates a Demodulation Reference Signal (DMRS) and generates downlink control information indicating a mapping pattern of the DMRS from a plurality of mapping patterns; and
a transmitter, which, in operation, transmits the DMRS and the downlink control information,
wherein the plurality of mapping patterns includes a first mapping pattern and a second mapping pattern,
wherein resource elements used for the DMRS of the second mapping pattern are same as a part of resource elements used for the DMRS of the first mapping pattern, and
wherein a number of the resource elements used for the DMRS of the first mapping pattern is larger than a number of the resource elements used for the DMRS of the second mapping pattern.
2. The communication apparatus according to claim 1 , wherein resource elements, which are used for the DMRS of the first mapping pattern and which are not used for the DMRS of the second mapping pattern, are used for a transmission of data in the second mapping pattern.
3. The communication apparatus according to claim 1 , wherein the first mapping pattern and the second mapping pattern have a resource element used for the DMRS in a first half of a time unit and in a second half of the time unit, the time unit being configured of 14 Orthogonal Frequency-Division Multiplexing (OFDM) symbols.
4. The communication apparatus according to claim 1 , wherein the downlink control information includes a plurality of bits that indicate the mapping pattern from the plurality of mapping patterns.
5. The communication apparatus according to claim 1 , wherein two adjacent Orthogonal Frequency-Division Multiplexing (OFDM) symbols are used for a DMRS transmission for at least one of the plurality of mapping patterns.
6. The communication apparatus according to claim 1 , wherein the plurality of the mapping patterns is indicated by a higher layer signaling.
7. The communication apparatus according to claim 1 , wherein the downlink control information is transmitted on a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH).
8. The communication apparatus according to claim 1 , wherein each of the plurality of the mapping patterns has a different density of DMRS in a frequency domain.
9. The communication apparatus according to claim 1 , wherein each of the plurality of the mapping patterns has a different density of DMRS in a time domain.
10. A communication method comprising:
generating a Demodulation Reference Signal (DMRS) and downlink control information indicating a mapping pattern of the DMRS from a plurality of mapping patterns; and
transmitting the DMRS and the downlink control information,
wherein the plurality of mapping patterns includes a first mapping pattern and a second mapping pattern,
wherein resource elements used for the DMRS of the second mapping pattern are same as a part of resource elements used for the DMRS of the first mapping pattern, and
wherein a number of the resource elements used for the DMRS of the first mapping pattern is larger than a number of the resource elements used for the DMRS of the second mapping pattern.
11. The communication method according to claim 10 , wherein resource elements, which are used for the DMRS of the first mapping pattern and which are not used for the DMRS of the second mapping pattern, are used for a transmission of data in the second mapping pattern.
12. The communication method according to claim 10 , wherein the first mapping pattern and the second mapping pattern have a resource element used for the DMRS in a first half of a time unit and in a second half of the time unit, the time unit being configured of 14 Orthogonal Frequency-Division Multiplexing (OFDM) symbols.
13. The communication method according to claim 10 , wherein the downlink control information includes a plurality of bits that indicate the mapping pattern from the plurality of mapping patterns.
14. The communication method according to claim 10 , wherein two adjacent Orthogonal Frequency-Division Multiplexing (OFDM) symbols are used for a DMRS transmission for at least one of the plurality of mapping patterns.
15. The communication method according to claim 10 , wherein the plurality of the mapping patterns is indicated by a higher layer signaling.
16. The communication method according to claim 10 , wherein the downlink control information is transmitted on a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH).
17. The communication method according to claim 10 , wherein each of the plurality of the mapping patterns has a different density of DMRS in a frequency domain.
18. The communication method according to claim 10 , wherein each of the plurality of the mapping patterns has a different density of DMRS in a time domain.