Rate determination in high efficiency wireless LAN
View Patent ↗The present invention relates to a method and apparatus for determining a transmission rate in a Wireless Local Area Network (WLAN). According to one aspect of the present invention, a method for receiving an uplink frame from a Station (STA) by an Access Point (AP) in a WLAN may be provided. The method may include transmitting to the STA a downlink frame eliciting the uplink frame, and receiving the uplink frame from the STA at a rate determined based on whether the type of the uplink frame is a single user type or a multi-user type.
1. A method for receiving one or more uplink frames from one or more stations by an Access Point (AP) in a Wireless Local Area Network (WLAN), the method comprising:
transmitting, a first Modulation and Coding Scheme (MCS) map field for uplink single-user transmission and a second MCS map field for uplink multi-user transmission, the second MCS map field including a plurality of subfields, wherein the plurality of subfields respectively corresponds to a plurality of spatial stream numbers, and each sub-field indicates a maximum MCS for a corresponding spatial stream number;
transmitting, to the one or more stations, a downlink frame eliciting the one or more uplink frames; and
receiving the one or more uplink frames from the one or more stations, each uplink frame having a coding rate determined based on whether the downlink frame elicits multiple uplink frames to be simultaneously transmitted from multiple stations to the AP or a single uplink frame to be transmitted from a single station to the AP,
wherein the coding rate is determined based on the first MCS map field when the downlink frame elicits the single uplink frame, and
wherein the coding rate is determined based on the second MCS map field when the downlink frame elicits the multiple uplink frames.
2. The method according to claim 1 , wherein the receiving the one or more uplink frames from the one or more stations comprises:
when the downlink frame elicits the multiple uplink frames, receiving the multiple uplink frames, each uplink frame having a coding rate determined so that lengths of the multiple uplink frames are equal to each other.
3. The method according to claim 1 , wherein when the downlink frame elicits the multiple uplink frames, coding rates of the multiple uplink frames are equal to each other.
4. The method according to claim 1 , wherein the receiving the one or more uplink frames from the one or more stations comprises:
when the downlink frame elicits the single uplink frame, receiving the single uplink frame having a coding rate determined based on a coding rate of the downlink frame and Basic Service Set (BSS) basic rate set information.
5. The method according to claim 4 , wherein the receiving the one or more uplink frames from the one or more stations comprises:
when the downlink frame elicits the single uplink frame, receiving the single uplink frame having a highest coding rate of the BSS basic rate set information, equal to or lower than the coding rate of the downlink frame.
6. The method according to claim 4 , wherein the receiving the one or more uplink frames from the one or more stations comprises:
when the downlink frame elicits the single uplink frame, receiving the single uplink frame having a coding rate determined further based on Modulation and Coding Scheme (MCS) and Number of Spatial Streams (NSS) set information supported for transmission of the single uplink frame, and information about a number of encoders supported for transmission of the single uplink frame.
7. The method according to claim 1 , wherein the downlink frame is a trigger frame including scheduling information for transmission of the one or more uplink frames.
8. The method according to claim 1 , wherein the downlink frame is a data frame and the one or more uplink frames are control response frames.
9. The method according to claim 1 , wherein the receiving the one or more uplink frames from the one or more stations comprises:
when the downlink frame elicits the multiple uplink frames, receiving the multiple uplink frames, each uplink frame having a coding rate determined based on one or more of information about a coding rate or MCS limit on transmission of the multiple uplink frames, a rate of the downlink frame, BSS basic rate set information, MCS and NSS set information supported for transmission of the multiple uplink frames, information about a number of encoders supported for transmission of the multiple uplink frames.
10. A method for transmitting an uplink frame to an Access Point (AP) by a Station (STA) in a Wireless Local Area Network (WLAN), the method comprising:
receiving, a first Modulation and Coding Scheme (MCS) map field for uplink single-user transmission and a second MCS map field for uplink multi-user transmission, the second MCS map field including a plurality of subfields, wherein the plurality of subfields respectively corresponds to a plurality of spatial stream numbers, and each sub-field indicates a maximum MCS for a corresponding spatial stream number;
receiving, from the AP, a downlink frame eliciting one or more uplink frames;
determining a first coding rate based on whether the downlink frame elicits multiple uplink frames to be simultaneously transmitted from multiple stations to the AP or a single uplink frame to be transmitted from a single station to the AP; and
transmitting a first uplink frame having the first coding rate to the AP,
wherein determining the first coding rate comprises:
determining the first coding rate based on the first MCS map field when the downlink frame elicits the single uplink frame, and
determining the first coding rate based on the second MCS map field when the downlink frame elicits the multiple uplink frames.
11. The method according to claim 10 , wherein when the downlink frame elicits the multiple uplink frames, the first coding rate is determined so that lengths of the multiple uplink frames are equal to each other.
12. The method according to claim 10 , wherein when the downlink frame elicits the multiple uplink frames, the first coding rate is determined so that coding rates of the multiple uplink frames are equal to each other.
13. The method according to claim 10 , wherein when the downlink frame elicits the single uplink frame the first coding rate is determined based on a coding rate of the downlink frame and Basic Service Set (BSS) basic rate set information.
14. The method according to claim 13 , wherein when the downlink frame elicits the single uplink frame the first coding rate is determined as a highest coding rate of the BSS basic rate set information, equal to or lower than the coding rate of the downlink frame.
15. The method according to claim 13 , wherein
when the downlink frame elicits the single uplink frame the first coding rate is determined further based on Modulation and Coding Scheme (MCS) and Number of Spatial Streams (NSS) set information supported for transmission of the single uplink frame, information about a number of encoders supported for transmission of the single uplink frame.
16. The method according to claim 10 , wherein the downlink frame is a trigger frame including scheduling information for transmission of the one or more uplink frames.
17. The method according to claim 10 , wherein the downlink frame is a data frame and the one or more uplink frames are control response frames.
18. The method according to claim 17 , wherein
when the downlink frame elicits the multiple uplink frames the first coding rate is determined based on one or more of information about a coding rate or MCS limit on transmission of the multiple uplink frames, a coding rate of the downlink frame, BSS basic rate set information, MCS and NSS set information supported for transmission of the multiple uplink frames, information about a number of encoders supported for transmission of the multiple uplink frames.