METHOD FOR TRANSMITTING AND RECEIVING PHYSICAL LAYER CONVERGENCE PROCEDURE PROTOCOL DATA UNIT IN WIRELESS LOCAL AREA NETWORK SYSTEM SUPPORTING POWER SAVE MODE OPERATION AND APPARATUS FOR THE SAME

• US 20140086131A1
• Filed: 11/23/2011
• Published: 03/27/2014
• Est. Priority Date: 05/31/2011
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Seok, Yong Ho
• Granted Patent: US 9,237,521 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 72/1263 Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method of transmitting a data frame in a wireless local area network (WLAN) is provided. The method includes transmitting, by an access point (AP), a scheduling information element including information on a time period for data frame transmission to a first station (STA) and a second STA, wherein the scheduling information element includes an offset field indicating a start time point of the time period and transmitting, by the AP, the data frame to the first STA and the second STA by using a multi user-multiple input multiple output (MU-MIMO) transmission scheme after the start time point indicated by the offset field.

Claims

1. A method of transmitting a data frame in a wireless local area network (WLAN), the method comprising:

transmitting, by an access point (AP), a scheduling information element including information on a time period for data frame transmission to a first station (STA) and a second STA, wherein the scheduling information element includes an offset field indicating a start time point of the time period; and

transmitting, by the AP, the data frame to the first STA and the second STA by using a multi user-multiple input multiple output (MU-MIMO) transmission scheme after the start time point indicated by the offset field.

2. The method of claim 1, further comprising operating, by the first STA and the second STA, by transitioning to an awake state at the start time point indicated by the offset field.

3. The method of claim 2,

wherein the scheduling information element includes a group identifier indicating a target STA group of the data frame transmission, and

wherein the target STA group includes the first STA and the second STA.

4. The method of claim 3, wherein the operating by transitioning to the awake state comprising:

determining, by each STA of the first STA1 and the second STA2, whether the each STA is a member STA of the target STA group on the basis of the group identifier field of the scheduling information element; and

if the each STA is the member STA, operating, by the each STA, by transitioning to the awake state.

5. The method of claim 4,

wherein the scheduling information element further includes a duration field indicating a duration of the time period, and

wherein transmitting of the data frame is performed within the duration indicated by the duration field.

6. The method of claim 5, further comprising operating, by the first STA and the second STA, by transitioning to a doze state when the time period elapses from the start time point.

7. The method of claim 6, wherein the scheduling information element further includes an interval subfield indicating an interval in which the time period is resumed periodically, and

further comprising operating, by the first STA and the second STA, by transitioning to the awake state in every interval with respect to the start time point.

8. The method of claim 4,

wherein the data frame includes a data unit and a signal field including information for interpreting the data frame, and

wherein the signal field includes the group identifier and an indicator indicating the number of spatial streams respectively assigned to the first STA and the second STA.

9. The method of claim 8, further comprising operating, by the first STA and the second STA, by transitioning to a doze state when the indicator indicates that the number of assigned spatial streams is 0.

10. The method of claim 1, further comprising:

receiving, by the AP, a first trigger frame from the first STA to announce that the first STA is ready to receive the data frame after the start time point; and

receiving, by the AP, a second trigger frame from the second STA to announce that the second STA is ready to receive the data frame after the start time point.

11. The method of claim 10, wherein the data frame is transmitted after receiving the first trigger frame and the second trigger frame.

12. A wireless apparatus comprising:

a transceiver for transmitting and receiving a radio signal; and

a processor functionally coupled to the transceiver,

wherein the processor is configured for;

transmitting a scheduling information element including information on a time period for data frame transmission to a first STA and a second STA, wherein the scheduling information element includes an offset field indicating a start time point of the time period; and

transmitting the data frame to the first STA and the second STA by using a MU-MIMO transmission scheme after the start time point indicated by the offset field.