Method and apparatus for transmitting a physical protocol data unit by applying cyclic shift delay for each transmission chain in a wireless local area network system

A transmitting device transmitting a Physical Protocol Data Unit (PPDU) in a wireless LAN system, the transmitting device comprising:

• a memory;
• a transceiver;
• and
• a processor coupled operatively to the memory and the transceiver, wherein the processor is configured to:
• generate the PPDU;
• and
• transmit the PPDU to a receiving device,
• wherein:
• the PPDU includes a legacy field and an Extreme High Throughput (EHT) field,
• the legacy field includes a Very High Throughput-Short Training Field (VHT-STF) and a High Efficiency (HE)-STF,
• the EHT field includes an EHT-STF and a data field,
• the EHT field is composed based on a Cyclic Shift Delay (CSD) value for each transmit chain,
• the CSD value is determined as a candidate CSD value that minimizes a sum of a first absolute value and a second absolute value based on a power ratio,
• the power ratio is a ratio of reception power of the VHT-STF or the HE-STF or the EHT-STF to reception power of the data field,
• the first absolute value is an absolute value of a value related to 5 percent of a Cumulative Distribution Function (CDF) of the power ratio,
• the second absolute value is an absolute value of a value related to 95 percent of the CDF of the power ratio,
• a CSD value for a 9th transmit chain is determined among candidate CSD values,
• a CSD value for a 10th transmit chain is determined based on the CSD value for the 9th transmit chain,
• a CSD value for a 11th transmit chain is determined based on the CSD values for the 9th and 10th transmit chains,
• a CSD value for a 12th transmit chain is determined based on the CSD values for the 9th to 11th transmit chains,
• a CSD value for a 13th transmit chain is determined based on the CSD values for the 9th to 12th transmit chains,
• a CSD value for a 14th transmit chain is determined based on the CSD values for the 9th to 13th transmit chains,
• a CSD value for a 15th transmit chain is determined based on the CSD values for the 9th to 14th transmit chains, and
• a CSD value for a 16th transmit chain is determined based on the CSD values for the 9th to 15th transmit chains.

A method for receiving a Physical Protocol Data Unit (PPDU) in a wireless LAN system, the method comprising:

• receiving, by a receiving device, a PPDU from a transmitting device;
• and
• decoding, by the receiving device, the PPDU,
• wherein:
• the PPDU includes a legacy field and an Extreme High Throughput (EHT) field,
• the legacy field includes a Very High Throughput-Short Training Field (VHT-STF) and a High Efficiency (HE)-STF,
• the EHT field includes an EHT-STF and a data field,
• the EHT field is composed based on a Cyclic Shift Delay (CSD) value for each transmit chain,
• the CSD value is determined as a candidate CSD value that minimizes a sum of a first absolute value and a second absolute value based on a power ratio,
• the power ratio is a ratio of reception power of the VHT-STF or the HE-STF or the EHT-STF to reception power of the data field,
• the first absolute value is an absolute value of a value related to 5 percent of a Cumulative Distribution Function (CDF) of the power ratio,
• the second absolute value is an absolute value of a value related to 95 percent of the CDF of the power ratio,
• a CSD value for a 9th transmit chain is determined among candidate CSD values,
• a CSD value for a 10th transmit chain is determined based on the CSD value for the 9th transmit chain,
• a CSD value for a 11th transmit chain is determined based on the CSD values for the 9th and 10th transmit chains,
• a CSD value for a 12th transmit chain is determined based on the CSD values for the 9th to 11th transmit chains,
• a CSD value for a 13th transmit chain is determined based on the CSD values for the 9th to 12th transmit chains,
• a CSD value for a 14th transmit chain is determined based on the CSD values for the 9th to 13th transmit chains,
• a CSD value for a 15th transmit chain is determined based on the CSD values for the 9th to 14th transmit chains, and
• a CSD value for a 16th transmit chain is determined based on the CSD values for the 9th to 15th transmit chains.