Prior art

The U.S. Patent 10306667B2, titled "Method for transmitting and receiving uplink acknowledgement signal in wireless LAN system and apparatus therefor," has a priority date of February 17, 2016. The core invention lies in efficiently transmitting uplink (UL) acknowledgement (ACK) signals in response to downlink (DL) multi-user data in a Wireless Local Area Network (WLAN) system by embedding UL scheduling information directly within the DL Physical Protocol Data Unit (PPDU), thereby avoiding the need for a separate trigger frame. This embedded control information subfield includes UL PPDU length, Resource Unit (RU) allocation, UL Modulation and Coding Scheme (MCS), Access Point (AP) transmit power, and AP target Receive Signal Strength Indicator (RSSI). A key inventive aspect also involves omitting certain parameters from this subfield (e.g., spatial reuse, Dual Carrier Modulation (DCM), bandwidth, Multi-User Multi-Input Multi-Output (MU MIMO) Long Training Field (LTF) mode, Space Time Block Code (STBC), number of streams, stream allocation, and coding type) and the Station (STA) inferring or setting default values for these omitted parameters.

All cited patent documents listed below are considered prior art under 35 U.S.C. § 102 as their effective filing or publication dates precede the priority date of US10306667B2 (February 17, 2016).

Here are the most relevant prior art documents cited in US10306667B2:

1. KR20070020033A

• Full Citation: KR20070020033A, "Multiple receiver set (MRA) with different data rates for IEEE 802.11N", Koninklijke Philips Electronics N.V., Publication Date: 2007-02-16.
• Publication/Filing Date: Publication: 2007-02-16; Priority: 2004-05-13.
• Brief Description: This patent describes methods for handling acknowledgment frames, specifically a Multiple Receiver Acknowledgment (MRA) frame, in an IEEE 802.11n WLAN system. It discusses sending a single data frame to multiple receivers and the corresponding ACK mechanisms, including signaling a desired transmit rate for subsequent acknowledgment frames within a MAC header.
• Potential Anticipation (35 U.S.C. § 102): While it touches upon multi-receiver ACKs and rate indication, it does not explicitly disclose embedding comprehensive uplink scheduling information (such as UL PPDU length, RU allocation, AP Tx power, target RSSI) directly within a downlink data PPDU to schedule an uplink multi-user ACK. Furthermore, it does not describe the specific omissions of fields (e.g., spatial reuse, DCM, bandwidth) and the corresponding STA behaviors claimed in US10306667B2. Therefore, it is unlikely to anticipate claims 1, 9, or 12.

2. KR20090087480A

• Full Citation: KR20090087480A, "A set of MAC protocol data units in the TDMA MAC layer", Thomson Licensing, Publication Date: 2009-08-17.
• Publication/Filing Date: Publication: 2009-08-17; Priority: 2006-12-15.
• Brief Description: This patent relates to scheduling data transmission within a TDMA MAC layer, focusing on sequences of MAC Protocol Data Units (MPDUs) and associated acknowledgement processes. It describes a scheduler that manages transmission opportunities and instructs stations on data transmission and acknowledgment timings.
• Potential Anticipation (35 U.S.C. § 102): This document deals with general scheduling and acknowledgments in a TDMA MAC context. It does not disclose the specific mechanism of embedding uplink scheduling information for an ACK within a downlink data PPDU in a WLAN system to trigger an immediate UL ACK, nor the detailed content and specific omissions of such scheduling information as defined in US10306667B2. It would not anticipate claims 1, 9, or 12.

3. KR20140103359A

• Full Citation: KR20140103359A, "Method and apparatus for sending very high throughput wlan acknowledgment frames", Qualcomm Incorporated, Publication Date: 2014-08-26.
• Publication/Filing Date: Publication: 2014-08-26; Priority: 2010-06-15.
• Brief Description: This patent describes methods for efficient acknowledgment (ACK) transmission in High Throughput (HT) or Very High Throughput (VHT) WLAN systems, including block acknowledgements (BAs) and multi-user block acknowledgements (MU-BAs). It discusses a downlink transmission that includes a control field indicating a desired ACK type and potentially an ACK schedule or identifier for the STA to respond. It also mentions scheduling multiple STAs for uplink multi-user ACK transmissions.
• Potential Anticipation (35 U.S.C. § 102): This reference is highly relevant as it describes scheduling ACKs (including MU-BAs) via a control field within a downlink transmission. This aligns with the general concept of US10306667B2 to embed ACK scheduling. However, US10306667B2 specifically defines the content of the control information subfield (UL PPDU length, RU allocation, UL MCS, AP Tx power, target RSSI) and, critically, the omission of other fields (spatial reuse, DCM, bandwidth, MU MIMO LTF mode, etc.) and the STA's subsequent inference or default actions. Without explicit disclosure of these precise details, it does not fully anticipate claims 1, 9, or 12, but it provides a strong foundation for the concept of DL-scheduled UL ACKs.

4. WO2015068968A1

• Full Citation: WO2015068968A1, "Method and device for receiving multiuser uplink in wireless lan", LG Electronics Inc., Publication Date: 2015-05-14.
• Publication/Filing Date: Publication: 2015-05-14; Priority: 2013-11-07.
• Brief Description: This patent describes an Access Point (AP) receiving multi-user uplink (UL) data in a WLAN system. It focuses on the AP transmitting a trigger frame that contains UL multi-user allocation information (e.g., resource unit (RU) allocation, modulation and coding scheme (MCS) information, spatial stream information) to schedule STAs for UL PPDU transmission.
• Potential Anticipation (35 U.S.C. § 102): This document clearly describes the prior art approach where a separate trigger frame is used for UL MU scheduling. US10306667B2 explicitly aims to overcome the overhead and delay associated with such separate trigger frames for ACK signals by embedding the scheduling information directly in the downlink data PPDU itself. Therefore, this patent would not anticipate claims 1, 9, or 12, but rather illustrates the problem US10306667B2 aims to solve.

5. KR20160013820A

• Full Citation: KR20160013820A, "Downlink acknowledgment in response to uplink multiple user transmission", Newracom, Inc., Publication Date: 2016-02-05.
• Publication/Filing Date: Publication: 2016-02-05; Priority: 2014-07-28.
• Brief Description: This patent describes methods for an AP to transmit a downlink acknowledgment (ACK) frame in response to an uplink multi-user (UL MU) transmission in a High Efficiency (HE) WLAN system. It focuses on the AP's role in sending ACKs (e.g., MU-BAs) after receiving UL MU data.
• Potential Anticipation (35 U.S.C. § 102): The subject of this patent is downlink acknowledgments for uplink multi-user transmissions, which is the inverse communication direction compared to US10306667B2 (uplink acknowledgments for downlink multi-user data). While it deals with multi-user ACKs in HE WLAN, its application context and specific technical problem are different. Thus, it does not anticipate claims 1, 9, or 12.

6. WO2016021831A1

• Full Citation: WO2016021831A1, "Multi-user transmission method in wireless communication system and device therefor", LG Electronics Inc., Publication Date: 2016-02-11.
• Publication/Filing Date: Publication: 2016-02-11; Priority: 2014-08-07.
• Brief Description: This patent, also by LG Electronics, describes a multi-user transmission method focusing on UL MU transmissions initiated by a trigger frame. It details the trigger frame's structure and includes various UL scheduling parameters such as bandwidth, duration, RU allocation, MCS, and Cyclic Prefix (CP)/LTF type. The AP receives UL MU PPDUs in response to the trigger frame and then sends a block acknowledgment (BA) or multi-user block acknowledgment (MU-BA).
• Potential Anticipation (35 U.S.C. § 102): Similar to WO2015068968A1, this patent describes the use of a separate trigger frame for UL MU scheduling, which is the problem US10306667B2 aims to overcome for ACK signaling. Although it lists specific UL scheduling parameters, it does not disclose embedding this information directly into a DL data PPDU for ACK scheduling, nor the specific field omissions and STA inferences that are central to US10306667B2. Therefore, it does not anticipate claims 1, 9, or 12.

7. US20160043855A1

• Full Citation: US20160043855A1, "Dynamic inter-frame space processing in high efficiency wireless lan", Newracom, Inc., Publication Date: 2016-02-11.
• Publication/Filing Date: Publication: 2016-02-11; Priority: 2014-08-08.
• Brief Description: This patent focuses on methods for dynamic inter-frame space (IFS) processing in High Efficiency (HE) WLAN systems to schedule subsequent transmissions. It describes an AP transmitting a PPDU that includes signaling for a subsequent UL MU transmission, potentially a trigger frame, and focuses on the timing and IFS settings for these transmissions and responses.
• Potential Anticipation (35 U.S.C. § 102): This reference broadly discusses scheduling and responses in HE WLAN, often involving trigger frames for UL MU transmissions. It emphasizes timing and IFS adjustments. However, it does not explicitly disclose embedding comprehensive UL ACK scheduling information (including specific fields and omissions) directly within a DL data PPDU, which is the inventive step of US10306667B2. It is unlikely to anticipate claims 1, 9, or 12.

8. US20180288800A1

• Full Citation: US20180288800A1, "Parallel data transmission method and apparatus", Huawei Technologies Co., Ltd., Publication Date: 2018-10-04.
• Publication/Filing Date: Publication: 2018-10-04; Priority: 2015-12-07.
• Brief Description: This patent describes methods for parallel data transmission in wireless communication systems, including MU-MIMO and OFDMA. It mentions transmitting a trigger frame carrying uplink (UL) resource allocation information for multiple user equipment (UEs) to transmit UL data.
• Potential Anticipation (35 U.S.C. § 102): Similar to other references, this patent describes UL resource allocation using a trigger frame. It does not describe embedding UL ACK scheduling information directly within a DL data PPDU for immediate response, which is the distinguishing feature of US10306667B2. Therefore, it does not anticipate claims 1, 9, or 12.

9. US20170255659A1

• Full Citation: US20170255659A1, "Basic service set identifications for using non-default spatial reuse parameters", Intel IP Corporation, Publication Date: 2017-09-07.
• Publication/Filing Date: Publication: 2017-09-07; Priority: 2016-01-29.
• Brief Description: This patent describes methods and apparatuses related to spatial reuse in WLAN systems, specifically for identifying basic service sets (BSSs) that utilize non-default spatial reuse parameters. It focuses on how BSSs manage frame transmissions based on channel conditions and spatial reuse rules.
• Potential Anticipation (35 U.S.C. § 102): This patent addresses the concept of spatial reuse, which is a specific element referenced in US10306667B2's claims. US10306667B2 specifically claims that its control information subfield may not include spatial reuse information, leading the STA to disable spatial reuse. While US20170255659A1 covers spatial reuse generally, it does not disclose the specific combination of embedding UL ACK scheduling within a DL data PPDU, the omission of spatial reuse information from this embedded scheduling, and the resulting default behavior of disabling spatial reuse for the UL ACK. Thus, it is unlikely to anticipate claims 1, 9, or 12 in their entirety, but it is relevant for the state of the art concerning spatial reuse.