Communication apparatus and communication method for channel estimation
View Patent ↗Provided is a communication apparatus and communication method for channel estimation. The communication apparatus includes a transmitter, which in operation, transmits a physical layer protocol data unit (PPDU) to one or more other communication apparatus in a multiple-input multiple-output (MIMO) wireless network. The PPDU includes a long training field (LTF) that permits the one or more other communication apparatus to estimate respective channels for respective communications with the communication apparatus. The communication apparatus includes a controller, which in operation, establishes the number of LTF symbols (N LTF ) for generating the LTF in the PPDU. The NLTF depends on a maximum value (N STSMAX ) of the number of space-time streams for each resource unit (RU) in the PPDU.
1. A communication apparatus comprising:
circuitry, which, in operation, sets a number of Extremely High Throughput Long training field (EHT-LTF) symbols in an physical layer protocol data unit (PPDU) for multi user transmission based on an initial number of EHT-LTF symbols that is specified by a number of spatial streams (Nss) of the PPDU, wherein the number of EHT-LTF symbols is set to be equal to or larger than the initial number of EHT-LTF symbols; and
a transmitter, which, in operation, transmits the PPDU,
wherein the Nss is larger than 8.
2. The communication apparatus according to claim 1 , wherein the number of EHT-LTF symbols is set to be larger than the initial number of EHT-LTF symbols.
3. The communication apparatus according to claim 1 , wherein the number of EHT-LTF symbols is determined from a number of EHT-LTF determination tables predetermined and stored in both the communication apparatus and a reception apparatus.
4. The communication apparatus according to claim 1 , wherein the PPDU comprises a preamble that indicates the number of EHT-LTF symbols.
5. The communication apparatus according to claim 1 , wherein the Nss is defined for each of resource units (RUs) allocated in the PPDU.
6. The communication apparatus according to claim 1 , wherein:
in a first case that the Nss is an even number, the initial number of EHT-LTF symbols is equal to the Nss; and
in a second case that the Nss is an odd number other than one, the initial number of EHT-LTF symbols is equal to 1 plus the Nss.
7. The communication apparatus according to claim 1 , wherein the number of EHT-LTF symbols is set based on a format of the PPDU.
8. A communication method comprising:
setting a number of Extremely High Throughput Long training field (EHT-LTF) symbols in an physical layer protocol data unit (PPDU) for multi user transmission based on an initial number of EHT-LTF symbols that is specified by a number of spatial streams (Nss) of the PPDU, wherein the number of EHT-LTF symbols is set to be equal to or larger than the initial number of EHT-LTF symbols; and
transmitting the PPDU,
wherein the Nss is larger than 8.
9. A communication apparatus comprising:
circuitry, which, in operation, sets a number of Extremely High Throughput Long training field (EHT-LTF) symbols in a trigger based physical layer protocol data unit (TB PPDU) based on an initial number of EHT-LTF symbols that is specified by a number of spatial streams (Nss) of the TB PPDU, wherein the number of EHT-LTF symbols is set to be equal to or larger than the initial number of EHT-LTF symbols;
a transmitter, which, in operation, transmits a trigger frame that solicits the TB PPDU; and
a receiver, which, in operation, receives the TB PPDU,
wherein the Nss is larger than 8.
10. The communication apparatus according to claim 9 , wherein the trigger frame indicates the number of EHT-LTF symbols.