Transmission apparatus and transmission method of resource assignment information
A transmission apparatus comprises an assignment information generator which, in operation, assigns resources on a resource unit (RU) basis to one or more terminal stations (STAs) and generates assignment information that specifies RUs allocated to the one or more STAs; a transmission signal generator which, in operation, generates a transmission signal that includes a legacy preamble, a non-legacy preamble and a data field, wherein the non-legacy preamble comprises a first signal field and a second signal field that carry a set ID and the assignment information, and wherein the set ID identifies one assignment set comprising the one or more STAs and a plurality of assignment indices, and wherein the assignment information comprises a resource assignment indication for each of a plurality of assignment which are referenced by the plurality of assignment indices; and a transmitter which, in operation, transmits the generated transmission signal.
1. A transmission apparatus comprising:
circuitry which, in operation, generates a transmission signal that includes a legacy preamble, a non-legacy preamble, and a data field, wherein
the non-legacy preamble includes a first signal field and a second signal field,
the second signal field indicates a plurality of resource units (RUs) in a frequency domain and includes a plurality of user-specific subfields containing user-specific information which identifies users associated with the plurality of user-specific subfields,
the RUs are formed of a plurality of tones that are identified by tone indices ordered in the frequency domain, the RUs are respectively formed of subsets of the tones, and a size and a location, in the frequency domain, of each RU are determined from a start tone index and an end tone index of the corresponding subset of the tones, and
the plurality of user-specific subfields correspond to the RUs, and the plurality of user-specific subfields are arranged such that the corresponding RUs are arranged in order of frequency; and
a transmitter which, in operation, transmits the generated transmission signal.
2. The transmission apparatus according to claim 1 , wherein the plurality of user-specific subfields include a first user-specific subfield and a second user-specific subfield, and the RU corresponding to the first user-specific subfield has a predetermined start tone index and the RU corresponding to the second user-specific subfield has a start tone index that is next to an end tone index of the RU corresponding to the first user-specific subfield.
3. The transmission apparatus according to claim 1 , wherein when at least one RU of the plurality of RUs is unused, the at least one RU is indicated by inserting a dummy assignment.
4. The transmission apparatus according to claim 1 , wherein the second signal field includes a first channel field for a first subband channel and, when the transmission signal occupies more than one subband channel, the second signal field further includes a second channel field for a second subband channel different from the first subband channel.
5. The transmission apparatus according to claim 4 , wherein each of the first channel field and the second channel field includes a common field, which includes a resource assignment subfield, and a user-specific field, which includes the plurality of user-specific subfields.
6. The transmission apparatus according to claim 5 , wherein the common field in each of the first channel field and the second channel field includes a center RU subfield indicating whether a center Type I RU is allocated when channel bandwidth is equal to 80 MHz.
7. The transmission apparatus according to claim 6 , wherein if the center Type I RU is allocated when channel bandwidth is equal to 80 MHz, a user-specific subfield for the center Type I RU is the last user-specific subfield in the plurality of user-specific fields.
8. The transmission apparatus according to claim 1 , wherein the second signal field includes a resource assignment subfield, and the resource assignment subfield and a position of a user-specific subfield together identify the RU used to transmit data to a specific user.
9. The transmission apparatus according to claim 1 , wherein the transmitter, in operation, selects a RU assignment according to quality information of the RUs reported by at least one user.
10. The transmission apparatus according to claim 1 , wherein the second signal field includes a common field, which includes a resource assignment subfield, and a user-specific field, which includes the plurality of user-specific subfields.
11. The transmission apparatus according to claim 1 , wherein the RUs are arranged in order of frequency from lower frequency to higher frequency.
12. A transmission method comprising:
generating a transmission signal that includes a legacy preamble, a non-legacy preamble and a data field, wherein
the non-legacy preamble includes a first signal field and a second signal field,
the second signal field indicates a plurality of resource units (RUs) in a frequency domain and includes a plurality of user-specific subfields containing user-specific information which identifies users associated with the plurality of user-specific subfields,
the RUs are formed of a plurality of tones that are identified by tone indices ordered in the frequency domain, the RUs are respectively formed of subsets of the tones, and a size and a location, in the frequency domain, of each RU are determined from a start tone index and an end tone index of the corresponding subset of the tones, and
the plurality of user-specific subfields correspond to the RUs, and the plurality of user-specific subfields are arranged such that the corresponding RUs are arranged in order of frequency; and
transmitting the generated transmission signal.
13. The transmission method according to claim 12 , wherein the plurality of user-specific subfields include a first user-specific subfield and a second user-specific subfield, and the RU corresponding to the first user-specific subfield has a predetermined start tone index and the RU corresponding to the second user-specific subfield has a start tone index that is next to an end tone index of the RU corresponding to the first user-specific subfield.
14. The transmission method according to claim 12 , wherein when at least one RU of the plurality of RUs is unused, the at least one RU is indicated by inserting a dummy assignment.
15. The transmission method according to claim 12 , wherein the second signal field includes a first channel field for a first subband channel and, when the transmission signal occupies more than one subband channel, the second signal field further includes a second channel field for a second subband channel different from the first subband channel.
16. The transmission method according to claim 15 , wherein each of the first channel field and the second channel field includes a common field, which includes a resource assignment subfield, and a user-specific field, which includes the plurality of user-specific subfields.
17. The transmission method according to claim 16 , wherein the common field in each of the first channel field and the second channel field includes a center RU subfield indicating whether a center Type I RU is allocated when channel bandwidth is equal to 80 MHz.
18. The transmission method according to claim 17 , wherein if the center Type I RU is allocated when channel bandwidth is equal to 80 MHz, a user-specific subfield for the center Type I RU is the last user-specific subfield in the plurality of user-specific fields.
19. The transmission method according to claim 12 , wherein the second signal field includes a resource assignment subfield, and the resource assignment subfield and a position of a user-specific subfield together identify the RU used to transmit data to a specific user.
20. The transmission method according to claim 12 , comprising selecting a RU assignment according to quality information of the RUs reported by at least one user.
21. The transmission method according to claim 12 , wherein the second signal field includes a common field, which includes a resource assignment subfield, and a user-specific field, which includes the plurality of user-specific subfields.
22. The transmission method according to claim 12 , wherein the RUs are arranged in order of frequency from lower frequency to higher frequency.