# US 2019/0174555 A1 · Symmetric transmit opportunity (txop) truncation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0174555 A1 - Document ID: US20190174555A1 - Status: Published application - Kind: A1 - Application number: 16/122,828 - Filed: 2018-09-05 - Published: 2019-06-06 - Earliest claimed: 2005-11-08 - Assignees: Intellectual Ventures I LLC - Applicants: Intellectual Ventures I LLC - Inventors: Menzo Wentink - Web page: https://patentgrep.com/patent/US20190174555A1 ## CPC - H04W 74/0891: {for synchronized access} - H04N 21/4126: {The peripheral being portable, e.g. PDAs or mobile phones} - H04W 28/12: using signalling between network elements - H04W 74/08: Non-scheduled access, e.g. ALOHA (hybrid access H04W74/02) - H04W 74/0816: with collision avoidance - H04W 74/0866: {using a dedicated channel for access} - H04W 28/04: Error control - H04W 84/12: WLAN [Wireless Local Area Networks] - H04W 92/10: between terminal device and access point, i.e. wireless air interface - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Various embodiments of symmetric transmit opportunity (TXOP) truncation (STT) systems and methods are disclosed. One method embodiment, among others, comprises receiving a frame that truncates a TXOP around a first station, and responsive to receiving the frame, sending a second frame that truncates the TXOP around a second station. Others system and method embodiments are disclosed. ## Claims ### Claim at position 1 1-20. (canceled) ### Claim 21 A wireless communication method, comprising: receiving, at a first device, a first truncation frame from a second device, in response to receiving the first truncation frame, truncating, at the first device, a transmit opportunity (TXOP) around the second device; generating, at the first device in response to receiving the first truncation frame, a second truncation frame, wherein the second truncation frame is configured to truncate the TXOP around the first device at a third device; and transmitting, from the first device to the third device, the second truncation frame. ### Claim 22 (depends on 21) The wireless communication method of claim 21, further comprising receiving, at the first device from the third device, a third truncation frame, wherein the third truncation frame is configured to truncate the TXOP around the third device at the first device. ### Claim 23 (depends on 22) The wireless communication method of claim 22, wherein the second truncation frame comprises a CF-end frame and an identifier of the second device, and wherein the third truncation frame comprises the identifier. ### Claim 24 (depends on 23) The wireless communication method of claim 23, wherein the first truncation frame comprises an address of the first device. ### Claim 25 (depends on 24) The wireless communication method of claim 24, wherein the address is denoted in a basic service set identifier (BSSID). ### Claim 26 (depends on 21) The wireless communication method of claim 21, wherein the first and second truncation frames comprise CF-end frames. ### Claim 27 (depends on 21) The wireless communication method of claim 21, wherein the first truncation frame is sent from the first station at a non-basic rate. ### Claim 28 (depends on 21) The wireless communication method of claim 21, wherein the second truncation frame comprises the address of the third device. ### Claim 29 (depends on 21) The wireless communication method of claim 21, wherein the first device is a client station of the second device. ### Claim 30 (depends on 21) The wireless communication method of claim 21, wherein the second device is an access point of a network. ### Claim 31 An apparatus comprising: a processor; and a memory having instructions stored thereon that, when executed by the processor, cause the apparatus to: truncate a transmit opportunity (TXOP) around a second device in response to receiving a first truncation frame from the second device; generate a second truncation frame; and transmit, to a third device, the second truncation frame, wherein the second truncation frame is configured to truncate the TXOP around the apparatus at the third device. ### Claim 32 (depends on 31) The first device of claim 31, wherein the memory further comprises instructions stored thereon that, when executed by the processor, cause the second device to receive, at the first device from the third device, a third truncation frame. ### Claim 33 (depends on 32) The first device of claim 32, wherein the memory further comprises instructions stored thereon that, when executed by the processor, cause the second device to truncate the TXOP around the third device in response to receiving the third truncation frame. ### Claim 34 (depends on 31) The apparatus of claim 31, wherein the memory further comprises instructions stored thereon that, when executed by the processor, cause the second device to transmit, to the second device and in response to receiving the first truncation frame, a fourth truncation frame, wherein the fourth truncation frame is configured to truncate the TXOP around the first device at the second device. ### Claim 35 (depends on 31) The apparatus of claim 31, wherein the second truncation frame comprises an address of the third device and a CF-end frame. ### Claim 36 (depends on 35) The apparatus of claim 35, wherein the address of the first device comprises a basic service set identification (BSSID) field. ### Claim 37 (depends on 31) The apparatus of claim 31, wherein the second truncation frame is transmitted after a short interframe space (SIFS) field. ### Claim 38 A non-transitory, computer-readable medium having instructions stored there-on for performing a communication truncation, the instructions comprising: instructions for, in response to receiving a first truncation frame, truncating an existing TXOP around a second device; instructions for, in response to receiving the first truncation frame, generating a second truncation frame; and instructions for sending, to a third device from the first device, the second truncation frame, wherein the second truncation frame is configured to truncate the TXOP around the first device at the third device. ### Claim 39 (depends on 38) The non-transitory, computer-readable medium of claim 38, wherein the instructions further comprise instructions for, in response to receiving a third truncation frame from the third device, truncating the TXOP around the third device at the first device. ### Claim 40 (depends on 38) The non-transitory, computer-readable medium of claim 38, wherein the instructions further comprise instructions for sending, to the second device and in response to receiving the first truncation frame, a fourth truncation frame, wherein the fourth truncation frame is configured to truncate the TXOP around the first device at the second device.