Method and system for full duplex communication - Patent Application 20070123333

Abstract

A method and system for full duplex (FD) communication is provided. [Solution] In the system 100, in response to receiving a trigger frame from an access point (AP) 102, a second station (STA) 104-1 obtains a signal strength measurement during transmission of a first uplink reference frame by a first STA 104-5, and transmits a report frame to the AP 102 including information regarding the signal strength measurement.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. patent application Ser. No. 15 / 916,989, filed Mar. 9, 2018, and entitled “Methods and Systems for Full Duplex Communications,” the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to methods and systems for full-duplex communication. In particular, the present disclosure relates to methods and systems that aid in managing interference in full-duplex communication. [Background technology]

[0003] In full-duplex (FD) communication, downlink (DL) transmissions (e.g., from an access point (AP) to a station (STA)) and uplink (UL) transmissions (e.g., from a STA to an AP) can occur simultaneously. In asymmetric FD communication, DL transmissions occur between a pair of nodes (e.g., an AP and a first STA), but UL transmissions involve at least a different third node (e.g., an AP and a second STA).

[0004] In FD communication, UL and DL transmissions use the same time-frequency resources, and DL and UL transmissions may interfere with each other. Furthermore, asymmetric FD may be performed asynchronously, meaning that UL and DL transmissions may begin at different times. However, since asymmetric FD involves different STAs in DL and UL transmissions, individual STAs may not be able to cancel interference. Summary of the Invention

[0005] It would be desirable to provide a mechanism for managing such interference, for example a mechanism that can be implemented by an FD-capable AP. [Means for solving the problem]

[0006] In various examples described herein, methods and systems for performing FD communication are described. During (or in anticipation of) a DL transmission from an AP to a first STA, the AP can select a second STA for UL transmission using the same time-frequency resource. Similarly, during (or in anticipation of) a UL transmission from a first STA to the AP, the AP can select a second STA for DL ​​transmission using the same time-frequency resource. The AP can obtain information about potential FD interference at individual STAs and use such information to select one or more STAs for UL transmission with little or no significant interference to the STA receiving the DL transmission. In this disclosure, an exemplary method is described in which the AP triggers measurements of potential interference by all associated STAs and each STA reports the measured potential interference to the AP.

[0007] In a first aspect, the present disclosure describes a method including a step of transmitting, by an access point (AP) having full duplex (FD) capability, a trigger frame that causes at least a first station (STA) to initiate an uplink (UL) reference frame to the AP, the trigger frame further causing at least one second STA to obtain signal strength measurements during the transmission of the UL reference frame, and a step of receiving, by the AP, a report frame from the at least one second STA that includes information regarding the signal strength measurements.

[0008] In some examples of the first aspect, the method includes selecting a UL transmitting STA for a FD UL transmission during a DL transmission based on information included in the report frame. In some examples, the method includes storing potential interference information in the AP determined from information included in the report frame, where the potential interference information, for a given DL receiving STA, indicates any acceptable UL transmitting STAs for a FD UL transmission during a DL transmission to the given DL receiving STA, and the selecting the UL transmitting STA is performed using the stored potential interference information.

[0009] In some examples of the first aspect, the method includes selecting a DL receiving STA for a FD DL transmission during a UL transmission based on information included in the report frame. In some examples, the method includes storing potential interference information in the AP determined from the information included in the report frame, where the potential interference information, for a given UL transmitting STA, indicates any acceptable DL receiving STAs for a simultaneous FD DL transmission during a UL transmission by the given UL transmitting STA. In some examples, the selecting the DL receiving STA is performed using the stored potential interference information.

[0010] In some examples of the first aspect, the trigger frame causes multiple STAs to begin transmitting respective UL reference frames to the AP, with each UL reference frame being transmitted sequentially.

[0011] In some examples of the first aspect, the trigger frame indicates at least one of an identifier of the first STA, a transmission parameter for transmitting a UL response transmission, or a reporting parameter for the report frame. In some examples, the transmission parameter includes at least one of an indicator of a transmit power, an indicator of a time-frequency pattern of reference symbols, an indicator of precoding to be used, an indicator of a transmission duration, or an indicator of a transmission resource to be used. In some examples, the reporting parameter includes at least one of an indicator of an acceptable interference threshold, an indicator of a maximum number of acceptable interference sources, or an indicator of a time for transmitting the report frame.

[0012] In some examples of the first aspect, the AP has capability for asynchronous FD communication.

[0013] In some examples of the first aspect, the AP has capability for synchronous FD communication.

[0014] In some examples of the first aspect, the method includes retransmitting, by the AP, a trigger frame to the first STA when a UL reference frame from the first STA is not received. In some examples, when a UL reference frame from the first STA is not received after a preset time period or after a preset number of retransmissions, the first STA is excluded from FD transmission for at least a defined time period.

[0015] In a second aspect, a method is described that includes, in response to receiving a trigger frame from an access point (AP), acquiring, by a second station (STA), a signal strength measurement during transmission of a first uplink (UL) reference frame by a first STA, and transmitting a report frame to the AP that includes information regarding the signal strength measurement.

[0016] In some examples of the second aspect, the information included in the report frame includes at least one of an identifier of a source of the measured signal power or the measured signal strength. In examples, the information included in the report frame includes only an identifier for the measured signal power or any signal strength measurements within a defined acceptable interference threshold.

[0017] In some examples of the second aspect, the method includes transmitting, by the second STA, a second UL reference frame to the AP in response to receiving the trigger frame from the AP. In some examples, the second UL reference frame is transmitted by the second STA consecutively with the first UL reference frame by the first STA.

[0018] In a third aspect, an access point (AP) having full duplex (FD) capability and a communication interface for wireless communication with at least a first and a second station (STA) is described. The AP includes a processor configured to execute instructions to cause the AP to transmit a trigger frame, the trigger frame causing at least a first STA to initiate transmission of an uplink (UL) reference frame to the AP, the trigger frame further causing at least a second STA to obtain signal strength measurements during transmission of the UL reference frame, the signal strength measurements being measurements indicative of any potential interference caused by the UL transmission from the first STA and potentially affecting reception of a downlink (DL) transmission to the second STA, and to receive a report frame from the at least second STA including information regarding the signal strength measurements.

[0019] In some examples of the third aspect, the processor is further configured to execute instructions to cause the AP to select a UL transmitting STA for FD UL transmission during DL transmission based on information included in the reporting frame.

[0020] In some examples of the third aspect, the processor is further configured to execute instructions to cause the AP to select a DL receiving STA for FD DL transmission during UL transmission based on information included in the reporting frame.

[0021] In some examples of the third aspect, the trigger frame indicates at least one of an identifier of the first STA, a transmission parameter for transmitting the UL reference frame, or a reporting parameter for the reporting frame.

[0022] In a fourth aspect, a first station (STA) having a communication interface for wireless communication with an access point (AP) is described, the first STA including a processor configured to execute instructions to cause the first STA to obtain signal strength measurements during transmission of a first uplink (UL) reference frame by a second STA in response to receiving a trigger frame from the AP, the signal strength measurements being measurements indicative of any potential interference caused by the UL transmission from the second STA potentially affecting reception of a simultaneous downlink (DL) transmission to the first STA, and to transmit a report frame to the AP including information about the signal strength measurements.

[0023] In some examples of the fourth aspect, the processor is further configured to execute instructions to cause the first STA to transmit a second UL reference frame to the AP in response to receiving the trigger frame from the AP.

[0024] Reference will now be made to the accompanying drawings which illustrate, by way of example, exemplary embodiments of the present application. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of interference between DL and UL transmissions during FD communication. [Diagram 2] FIG. 1 is a block diagram illustrating an example device suitable for performing FD communications. [Diagram 3] FIG. 1 is a schematic diagram illustrating example operations for obtaining measurements of potential FD interference. [Figure 4] 4 is a timing diagram illustrating an example implementation of the operations of FIG. 3. [Diagram 5] 4 is a timing diagram illustrating another exemplary implementation of the operations of FIG. 3. [Figure 6] FIG. 11 is a schematic diagram illustrating another set of example operations for obtaining measurements of potential FD interference. [Figure 7] 7 is a timing diagram illustrating an example implementation of the operations of FIG. 6. [Figure 8]1 is an example table that may be used to report potential interference measurements to an AP. [Figure 9] 1 is an example table that may be used to store potential interference information in an AP. [Figure 10] 5 is a flowchart illustrating an example method for collecting potential interference information by an AP. [Figure 11] 4 is a flowchart illustrating an example method for obtaining potential interference measurements by a STA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Similar reference numbers may be used in the various drawings to denote similar elements.

[0027] Examples described herein provide a method and system for managing interference in full-duplex (FD) communication. An access point (AP) can transmit a trigger frame, e.g., an FD interference measurement trigger frame, that causes some or all of associated stations (STAs) to perform an operation to measure potential interference. For example, a STA can transmit a response frame or a reference frame, e.g., an FD interference reference frame, that can be used by other STAs to measure potential interference from a transmitting STA. After the potential interference is measured, each STA can report the measured potential interference to the AP in a report frame, e.g., an FD interference measurement report frame. The AP can use the potential interference information obtained from the STAs to select one or more suitable STAs for asymmetric FD communication.

[0028] FIG. 1 is a schematic diagram of an example system 100 in which the methods described herein may be implemented. The system 100 illustrates a Wi-Fi infrastructure including an AP 102 having FD capabilities. The AP 102 may also be referred to as a Primary Control Point (PCP) or a base station. The AP 102 may be implemented, for example, as a router. In general, the AP 102 may refer to any component (or collection of components) configured to provide wireless access in a network, such as an evolved Node B (eNB), a macrocell, a femtocell, a distribution node, a Wi-Fi AP, or other wireless-enabled devices. The AP 102 may provide wireless access, for example, according to one or more wireless communication protocols, for example, Long Term Evolution (LTE), LTE Advanced (LTE-A), High Speed ​​Frame Access (HSPA), Wi-Fi 802.11a / b / g / n / ac / ad, and other 802.11 protocols. A number of STAs 104 are associated with the AP 102. Each STA 104 may operate independently of one another and with various capabilities. For example, each STA 104 may or may not have FD capabilities. In the illustrated example, there are six STAs labeled STA1 through STA6 (individually referred to as 104-1 through 104-6, and generally referred to as STAs 104). The STAs 104 may also be referred to as, for example, terminals, user devices, user equipment (UE), or clients. Each STA 104 may be any component (or collection of components) capable of wireless communication, such as any suitable electronic device (ED) capable of wireless communication, including, for example, a mobile or fixed device, such as a smartphone, laptop, cell phone, Internet of Things (IoT) device, tablet device, or any other wireless-enabled device, and the STAs 104 need not be identical to one another.

[0029] The system 100 can support communication between the AP 102 and each STA 104, as well as direct communication between the STAs 104 (also referred to as device-to-device communication). The STAs 104 can also function as repeaters for AP-to-STA or STA-to-STA communication. The AP 102 can also perform multi-user (MU) transmissions (e.g., transmissions from the AP 102 to multiple STAs 104 simultaneously), for example, by using directional antennas and / or by using frequency separation.

[0030] 2 is a block diagram of an example simplified processing system 200 that may be used to implement the embodiments disclosed herein. The example processing system 200 described below, or variations thereof, may be used to implement any one of the AP 102 or the STA 104. Other processing systems may be suitable for implementing the embodiments described in this disclosure and may include different components than those described below. Although FIG. 2 shows a single instance of each component, there may be multiple instances of each component in the processing system 200.

[0031] The processing system 200 may include one or more processing devices 202, such as a processor, microprocessor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), special purpose logic circuitry, or a combination thereof. The processing system 200 may optionally include one or more input / output (I / O) interfaces 204 to allow interfacing with one or more optional input devices 214 and / or output devices 216. The processing system 200 may include one or more network interfaces 206 for wired or wireless communication with a network (e.g., an intranet, the Internet, a P2P network, a WAN, and / or a LAN) or other nodes. The network interface 206 may include wired links (e.g., Ethernet cables) and / or wireless links (e.g., one or more antennas) for communication within and / or between networks.

[0032] The network interface 206 can provide wireless communication via one or more antennas. In this example, multiple antennas together form an antenna array 218, which can perform both transmit and receive functions. The antenna array 218 can enable directional communication using beamforming and beam tracking. In other examples, there can be separate antennas or separate antenna arrays for transmit and receive.

[0033] The processing system 200 may also include one or more storage units 208, which may include mass storage units such as solid state drives, hard disk drives, magnetic disk drives, and / or optical disk drives. The processing system 200 may include one or more memories 210, which may include volatile or non-volatile memory (e.g., flash memory, random access memory (RAM), and / or read-only memory (ROM)). The non-transitory memory 210 may store instructions for execution by the processing device 202, such as for performing the example methods described in this disclosure. The memory 210 may include an operating system and other software instructions, such as for implementing other applications / functions. In some examples, one or more datasets and / or modules may be provided by an external memory (e.g., an external drive in wired or wireless communication with the processing system 200) or may be provided by a transient or non-transitory computer-readable medium. Examples of non-transitory computer readable media include RAM, ROM, erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, CD-ROM, or other portable memory storage.

[0034] There may be a bus 212 that provides communication between components of the processing system 200, including the processing device 202, the optional I / O interface 204, the network interface 206, the storage unit 208, and / or the memory 210. The bus 212 may be any suitable bus architecture including, for example, a memory bus, a peripheral bus, or a video bus.

[0035] 2, optional input devices 214 (e.g., a keyboard, a mouse, a microphone, a touch screen, and / or a keypad) and optional output devices 216 (e.g., a display, a speaker, and / or a printer) are shown as being external to processing system 200. In other examples, one or more of input devices 214 and / or output devices 216 may be internal components of processing system 200.

[0036] Reference is again made to Figure 1. Figure 1 illustrates an example set of asymmetric FD communications and the resulting FD interference. The asymmetric FD communications may be asynchronous FD communications or synchronous FD communications. For simplicity, asynchronous FD communications are described below, but it should be understood that this is not limiting.

[0037] In one example of asynchronous FD communication, the AP 102 initiates a downlink (DL) transmission 110 to STA1 104-1. The DL transmission 110 may include a frame (e.g., a data frame) having a frame header (e.g., a physical layer (PHY) header or a medium access control (MAC) header) that provides information regarding an FD transmission opportunity (TXOP). Other STAs 104 associated with the AP 102 may also receive this TXOP information (e.g., by eavesdropping on the DL transmission 110). The STAs 104 may utilize the TXOP to send uplink (UL) transmissions to the AP 102 simultaneously with the DL transmission 110.

[0038] In this disclosure, FD communication is communication in which UL and DL transmissions at a node share the same time-frequency resources for at least a portion of the transmission. That is, a UL transmission received at a node and a DL transmission sent from the same node both use at least some of the same subcarriers simultaneously for at least a portion of the transmission. This should not be confused with FD emulation techniques such as Time Division Duplexing (TDD) (which separates the UL and DL signals in time) or Frequency Division Duplexing (FDD) (which separates the UL and DL signals in frequency).

[0039] In some examples, the AP 102 can select one or more particular STAs 104 for UL transmission. Multiple STAs 104 may be able to simultaneously transmit UL transmissions to the AP 102, for example, using a MU UL transmission mode. In the illustrated example, the AP 102 selects STA5 104-5 for a simultaneous UL transmission 120 with a DL transmission 110.

[0040] In another example of asynchronous FD communication, a UL transmission 120 may be initiated first, and then the AP 102 may select one or more particular STAs 104 for a simultaneous DL transmission 110. The DL transmission 110 may be transmitted to multiple STAs 104 simultaneously using, for example, a MU DL transmission mode. For example, a UL transmission 120 from STA5 104-5 may be initiated, and then the AP 102 may select STA1 104-1 for a simultaneous DL transmission 110.

[0041] Regardless of whether the DL transmission 110 or the UL transmission 120 is initiated first, the DL transmission 110 from the AP 102 to STA1 104-1 can potentially cause interference to the AP 102's reception of the UL transmission 120 from STA5 104-5. The AP 102 can take steps to manage and / or mitigate this self-interference. In this disclosure, the FD-capable AP 102 has functionality (which may be implemented in hardware and / or software) that allows the AP 102 to substantially limit any self-interference from the ongoing DL transmission 110 to the simultaneous UL transmission 120. In this disclosure, the mitigation of any self-interference caused by the DL transmission 110 from the AP 102 to STA1 104-1 is not described in detail. The UL transmission 120 can also cause interference 130 at the receiving STA 104, in this example STA1 104-1, which may not have sufficient capabilities to mitigate the interference 130. In some examples, the AP 102 can select STAs 104 for UL transmission 120 and / or DL ​​transmission 110 to mitigate interference 130 that the receiving STAs 104 would encounter.

[0042] For example, when the DL transmission 110 starts first, the selection of the STA 104 for the simultaneous UL transmission 120 may be based on information regarding the potential (or expected) interference that will be caused by the UL transmission 120. Similarly, for example, when the UL transmission 120 starts first, the selection of the STA 104 for the simultaneous DL transmission 110 may be based on information regarding the potential (or expected) interference that the DL transmission 110 will encounter. Additionally, the AP 102 may indicate an acceptable UL transmit power level to mitigate interference with the ongoing DL transmission 110. The AP 102 may also control the DL transmit power to mitigate interference from the ongoing UL transmission 120.

[0043] As mentioned above, the present disclosure is not limited to asynchronous FD communication. For example, the present disclosure may also be used (with appropriate modifications as necessary) for other radio access technologies (RATs), such as communications using licensed and / or unlicensed spectrum, and / or FD communications in cellular or other wireless networks. The present disclosure may be used to address FD interference issues for asynchronous or synchronous FD communications. For example, in the case of synchronous FD communications (e.g., in a cellular network) where both DL transmission 110 and UL transmission 120 are scheduled to start at the same time, the AP 102 may use information about the potential (or expected) interference that would be caused by the UL transmission 120 to select one or more suitable STAs 104 for the DL transmission 110 and schedule both the DL transmission 110 and the UL transmission 120 accordingly.

[0044] To more effectively manage interference, it would be useful for the AP 102 to have a way to obtain information regarding the potential FD interference that each STA 104 would cause to another STA 104. FIG. 3 illustrates an example set of operations for obtaining such potential interference information. In this disclosure, potential interference refers to interference that may be or is expected to be caused by a transmission. As described in various examples below, potential interference may be measured or estimated by measuring the power of UL transmissions that are not actually interfering with DL transmissions.

[0045] As shown in FIG. 3, the AP 102 transmits a trigger frame, such as an FD interference measurement trigger frame (FD-IMTF) 310, to associated STAs 104 regardless of whether the STAs 104 are FD-capable. As previously described, the STAs 104 can participate in FD communications with the FD-capable AP 102 regardless of whether the STAs 104 are FD-capable. FIG. 3 shows the transmission of the FD-IMTF 310 to STA5 104-5. However, it should be understood that the FD-IMTF 310 may be multicast to multiple STAs 104, e.g., to all associated STAs 104. When the STAs 104 receive the FD-IMTF 310, the STAs 104 can determine whether the FD-IMTF 310 is intended for them (e.g., based on the identification of the intended STAs included in the FD-IMTF 310). If the STA 104 is an intended STA, upon receiving the FD-IMTF 310, the STA 104 will respond to the AP 102 with a transmission of a response frame, e.g., a reference frame, such as an FD interference reference frame (FD-IRF) 320. For example, FIG. 3 shows the transmission of an FD-IRF 320 by STA5 104-5 to the AP 102.

[0046] When a given STA 104 transmits a FD-IRF 320 to the AP 102, the transmission is transmitted by the STA 104 in a manner similar to a normal UL transmission (e.g., according to the transmission parameters indicated in the FD-IMTF 310). The FD-IRF 320 may have any suitable format. For example, the FD-IRF 320 may be a relatively simple PHY signal carrying reference symbols or pilot signals, which may be spread across frequency and time resources according to a predetermined or known pattern. In some examples, the FD-IRF 320 may also include (e.g., in the PHY header) preamble information that enables backward compatibility and coexistence with legacy devices and / or other RATs (e.g., other devices operating according to other 802.11 standards).

[0047] In some examples, the AP 102 may take no action upon receipt of the FD-IRF 320 (e.g., the FD-IRF 320 may be ignored or rejected upon receipt by the AP 102). In some examples, the AP 102 may measure the signal quality (e.g., as indicated by received signal power or signal-to-interference-plus-noise ratio (SINR)) of the FD-IRF 320 received from the STA 104 to evaluate the quality of a potential UL transmission from that STA 104. Based on the measured signal quality, the AP 102 may provide feedback or instructions to the STA 104 to adjust the signal quality using, for example, closed-loop link adaptation (e.g., by adjusting the modulation and coding scheme (MCS) level). In some other examples, if the AP 102 does not receive the expected FD-IRF 320, this may indicate that the intended STA 104 was unable to decode the FD-IMTF 310 or that the intended STA 104 does not support or is configured not to respond to the FD-IMTF 310. In this disclosure, an intended STA 104 that fails to transmit an FD-IRF 320 in response to the FD-IMTF 310 is referred to as a non-responsive STA. A non-responsive STA does not participate in the measurement period. A "non-responsive" STA should not be confused with a "non-responsive" STA. In this disclosure, a non-responsive STA is a STA that is not an intended recipient of the FD-IMTF 310 that is not expected to respond to the FD-IMTF 310, although the non-responsive STA still participates in the measurement period (e.g., by measuring potential interference, as described further below).

[0048] If the AP 102 does not receive the expected FD-IRF 320, the AP 102 may retransmit the FD-IMTF 310 to the non-responsive intended STA 104 that failed to transmit the expected FD-IRF 320. The retransmission of the FD-IMTF 310 to the non-responsive STA 104 may occur before or after the transmission of other FD-IMTF 310 to other intended STAs. The retransmission of the FD-IMTF 310 to the non-responsive STA 104 may be performed a pre-configured number of times, and if the non-responsive STA 104 still fails to respond to the FD-IRF 320, the AP 102 may exclude the non-responsive STA 104 from the FD TXOP for one or more subsequent measurement periods. The AP 102 may include the non-responsive STA 104 again in other future measurement periods. In examples where the FD-IMTF 310 targets more than one STA 104 (e.g., as described further below with reference to FIG. 5), the AP 102 may exclude any non-responsive STA 104 from FD TXOPs for one or more subsequent measurement periods without attempting to retransmit the FD-IMTF 310. This may be to avoid ambiguity in other responding STAs 104. In some examples, if the non-responsive STA 104 remains non-responsive to the FD-IMTF 310 for a pre-configured time interval and / or for a pre-configured number of FD-IMTFs 310, the AP 102 may determine that the non-responsive STA 104 is a legacy device that does not have the capability to recognize and respond to the FD-IMTF 310 or that the non-responsive STA 104 is configured not to respond to the FD-IMTF 310. The AP 102 may exclude the non-responsive STA 104 from all future FD-IMTF 310 transmissions and from all future FD TXOPs. In some examples, the AP 102 may have already identified the non-responsive STA 104 (e.g., the STA has identified itself as a legacy device or as configured to be non-responsive), for example, through an exchange of management frames, and may filter out such identified non-responsive STA 104 prior to any FD-IMTF 310 attempts.

[0049] During the transmission of the FD-IRF 320 by the responding STA 104, the other STAs 104 (also referred to as non-responding STAs 104) measure the potential interference 130 that they would encounter in normal DL reception by measuring the signal strength of the FD-IRF 320. For example, FIG. 3 shows all STAs 104 other than STA5 104-5 measuring the potential interference 130 caused by the transmission of the FD-IRF 320 by STA5 104-5. The measured potential interference 130 is recorded by each STA along with an indication of the source of the potential interference (e.g., the logical index of the source STA). A STA 104 may obtain a potential interference measurement by measuring the power of any signal over its receiving channel during the transmission of the FD-IRF 320. A potential interference measurement is more generally a measurement of signal strength by a STA 104 during the transmission of a UL reference frame by another STA 104. Although referred to as a potential interference measurement, the STA 104 need not recognize the measurement as indicative of potential interference. From the STA 104 perspective, the potential interference measurement may simply be a signal strength measurement, which is then reported to the AP 102.

[0050] In an example where the AP 102 transmits multiple FD-IMTFs 310 sequentially, the last FD-IMTF 310 in the sequence may include an indication (e.g., an end-of-sequence flag) indicating that it is the last FD-IMTF 310 in the sequence, which allows the STAs 104 to determine an appropriate time to provide measured potential interference information to the AP 102 (e.g., as described further below). When the AP 102 retransmits a FD-IMTF 310 to a particular non-responding STA 104 after transmitting a sequence of FD-IMTFs 310 to other intended STAs, the AP 104 may indicate (e.g., using an end-of-sequence flag) that the last retransmission of the FD-IMTF 310 to the non-responding STA 104 is the last FD-IMTF 310 in the sequence.

[0051] FIG. 4 is a timing diagram illustrating an exemplary implementation of the operations depicted in FIG. 3. In the example of FIG. 4, the AP 102 transmits a multicast FD-IMTF 310 to all associated STAs 104. Each FD-IMTF 310 is intended for a particular STA 104 to respond with a FD-IRF 320. For example, the FD-IMTF 310 may include a parameter indicating the intended responding STA 104, such as a logical index or STA identifier (ID) of the intended STA 104. Each STA 104 associated with the AP 102 may be assigned a logical index. The logical index for each STA 104 may be assigned by the AP 102 dynamically (e.g., using the FD-IMTF 310) or semi-statically (e.g., using a management frame). All STAs 104 are capable of receiving the FD-IMTF 310. Only the intended STA 104 responds with a FD-IRF 320, and all other STAs 104 measure potential interference 130 during the transmission of the FD-IRF 320.

[0052] In the example shown in FIG. 4, the AP 102 transmits a FD-IMTF 310 intended for STA5 104-5. STA5 104-5 responds by transmitting a FD-IRF 320 substantially immediately (e.g., after a single short interframe space (SIFS)) after the FD-IMTF 310 is received. All other STAs 104 obtain potential interference measurements 330 by measuring any potential interference caused by the UL transmission by STA5 104-5. The other STAs 104 can use information included in the FD-IMTF 310, such as an identifier (e.g., a logical index or STA ID) of the intended STA 104, to identify the source of the measured potential interference (STA5 104-5 in this case) and can record the measured potential interference along with the identifier of the potential interference source. The AP 102 can transmit one or more FD-IMTFs 310 intended for one or more other intended STAs 104. For example, the AP 102 may transmit a FD-IMTF 310 to all other associated STAs 104, so that all STAs 104 may obtain measurements of potential interference from all other STAs 104 (except for any non-responsive or otherwise excluded STAs 104). The STAs 104 then report the measured potential interference to the AP 102 using a reporting frame, such as a FD Interference Measurement Report Frame (FD-IMRF), described further below.

[0053] The FD-IMTF 310 may include information that causes the intended STAs 104 to transmit the FD-IRF 320 according to certain parameters. In particular, the FD-IMTF 310 may cause the STAs 104 to transmit the FD-IRF 320 in a manner that mimics a normal UL transmission so that the measured potential interference is a good representation of the interference that would be encountered during an actual UL transmission. For example, the FD-IMTF 310 may include an indication of the power level, precoding, and duration to be used for the transmission of the FD-IRF 320. These parameters may be indicated separately within the FD-IMTF 310. In some examples, there may be one or more sets of predefined transmission parameters, and the FD-IMTF 310 may only include an indicator (e.g., an index) of the particular predefined set to use instead of indicating the transmission parameters separately. In some examples, the transmission parameters to be used may have already been indicated (e.g., by a previous FD-IMTF 310 or management frame) and may not need to be indicated again. The FD-IMTF 310 may also include information that causes other STAs 104 to measure potential interference and report the measured potential interference. For example, the FD-IMTF 310 may indicate to the other STAs 104 that the FD-IRF 320 is following, and the other STAs 104 may respond by listening and measuring the interference caused by the FD-IRF 320. The FD-IMTF 310 may include parameters to be used when reporting the measured potential interference, which are described further below.

[0054] FIG. 5 is a timing diagram illustrating another exemplary implementation of the operations shown in FIG. 3. In this example, rather than the FD-IMTF 310 causing a response from a single STA 104, the FD-IMTF 310 targets multiple STAs 104 (e.g., all associated STAs 104, or a group of two or more targeted STAs 104) and triggers the transmission of FD-IRFs 320 by the multiple STAs 104 in sequence. The FD-IMTF 310 may be transmitted as a single multicast to a group of STAs 104 associated with the AP 102 or to all STAs 104. The FD-IMTF 310 may include parameters that cause the STAs 104 to respond in sequence with their individual FD-IRFs 320. For example, the FD-IMTF 310 may indicate the sequence in which the STAs 104 should respond (e.g., indicate the sequence of logical indexes of the STAs 104). The FD-IMTF 310 may explicitly indicate the time for the STAs 104 to report the measured potential interference to the AP 102. In some examples, such an explicit indication of the reporting time is not used, and instead, the STA 104 may determine an appropriate time to report the measured potential interference based on the number of STAs 104 addressed by the FD-IMTF 310 (e.g., the reporting time may be the time slot immediately following the expected group response period, and the group response period may be calculated as the number of logical indexes indicated in the FD-IMTF 310 multiplied by the time period for one FD-IRF 310 transmission). The FD-IMTF 310 may also indicate the end of the trigger sequence (e.g., if two or more groups of STAs 104 are triggered separately). In general, the STA 104 may not report the measured potential interference to the AP 102 before the end of the response period (whether the response period is calculated by each STA 104 or explicitly indicated by the AP 102). The STA 104 may report the potential interference to the AP 102 after the end of the response period.It should be understood that although the calculated or explicitly indicated time for reporting is considered to be the time when the STA 104 can begin reporting to the AP 102, the STA 104 may not report at exactly that time in some cases (e.g., due to a failure of Clear Channel Assessment (CCA)).

[0055] After the STA 104 receives the FD-IMTF 310, the STA 104 uses the information contained in the FD-IMTF 310 to respond by transmitting an FD-IRF 320 to the AP 102 in the designated time slot and measures potential interference from other STAs 104 as they respond in their respective time slots. For example, the first STA 104 indicated in the sequence determines that it should begin transmitting an FD-IRF 320 SIFS after the end of the triggering FD-IMTF 310, and the nth STA 104 indicated in the sequence determines that it should begin transmitting an FD-IRF 310 a duration of (n SIFS plus (n-1) IRF durations) after the end of the triggering FD-IMTF 310 (if there is a SIFS separation between FD-IRF 320 transmissions). The STA 104 may also use the indicated sequence to identify the source of potential interference measured in a given time slot. 5, in response to the FD-IMTF 310, the STAs 104 each sequentially transmit a respective FD-IRF 320. The transmissions of the FD-IRFs 320 may be separated by a time gap (e.g., separated by a SIFS). During the transmission of the FD-IRFs 320, the non-responding STAs obtain potential interference measurements 330 and record the potential interference measurements, as described above.

[0056] FIG. 6 illustrates another example set of operations for obtaining potential interference information. The example operations illustrated in FIG. 6 may be suitable when MU UL multiplexing (e.g., in the frequency domain and / or the spatial domain) is used. Using MU UL multiplexing allows two or more STAs 104 to transmit their respective FD-IRFs 320 in parallel to the AP 102 in response to the FD-IMTF 310. For example, the AP 102 may transmit a multicast FD-IMTF 310 targeted to a group of STAs 104, and the targeted group of STAs 104 may respond at the same time (e.g., immediately after the SIFS) using different resources.

[0057] The FD-IMTF 310 may include information similar to that described above with respect to Figures 3-5, such as information indicating the intended STAs 104, information indicating transmission parameters to be used to the FD-IRF 320, and / or information indicating how interference is measured and reported by non-responding STAs 104. In the case of MU UL multiplexing, the FD-IMTF 310 may include an identifier for each STA 104 in a group of intended responding STAs 104, or may include a group identifier that identifies the intended responding STAs 104 as a group. The FD-IMTF 310 may also include information indicating resources (e.g., frequency or spatial resources) to be used by each responding STA 104, so that the responding STAs 104 do not collide with each other in the MU UL transmissions of the FD-IRF 320. The FD-IMTF 310 may also indicate other transmission parameters (e.g., transmit power levels, precoding, and / or transmit durations) to be used by the responding STAs 104 individually or collectively.

[0058] When the FD-IMTF 310 indicates a particular resource to be used for the FD-IRF 320 transmission, the measured potential interference obtained by the non-responding STAs 104 is a resource-specific potential interference measurement. Although described in the context of a MU UL transmission, in some examples, the FD-IMTF 310 format described with respect to FIG. 6 may be used to obtain resource-specific interference measurements even when MU UL multiplexing is not used. For example, the FD-IMTF 310 may indicate only one responding STA 104, or may indicate two or more STAs 104 responding in sequence, and may also indicate the particular resource to be used by each responding STA 104.

[0059] In some examples, the FD-IMTF 310 may indicate to a group of intended STAs 104 to transmit their respective FD-IRFs 320 on the same time-frequency resources of the channel, but using different spatial resources (e.g., using their normal UL MU precoding). All other non-responding STAs 104 may obtain potential interference measurements. In another example, the FD-IMTF 310 may indicate to a group of intended STAs 104 to transmit their respective FD-IRFs 320 on the same time-frequency resources, but using different spatial resources, which are a subset of the full channel bandwidth. This may be the case when using Orthogonal Frequency Division Multiple Access (OFDMA) as in IEEE 802.11ax, for example, where the frequency resource assignment is semi-persistent. Other non-responding STAs 104 that are assigned the same frequency resources may obtain potential interference measurements. In another example, the FD-IMTF 310 may indicate to two groups of intended STAs 104 to transmit their respective FD-IRFs 320 simultaneously, but using different respective orthogonal frequency resources. All other non-responding STAs 104 may obtain potential interference measurements.

[0060] FIG. 7 is a timing diagram illustrating an example implementation of the operations illustrated in FIG. 6. In this example, the AP 102 transmits a multicast FD-IMTF 310 to all associated STAs 104. The FD-IMTF 310 indicates that STA3 104-3 and STA5 104-5 are the intended responding STAs 104, and also indicates the respective resources to be used by each of STA3 104-3 and STA5 104-5 to respond. After STA3 104-3 and STA5 104-5 receive the FD-IMTF 310, STA3 104-3 and STA5 104-5 are triggered to transmit their respective FD-IRFs 320 in parallel, each over their respective indicated resources. The non-responding STAs 104 each obtain potential interference measurements 330 during this time. As shown in Figure 7, the AP 102 may then transmit an FD-IMTF 310 to individual STAs 104 (e.g., STA6 104-6) in a manner similar to that shown in Figure 4 to measure potential interference from other associated STAs 104. The AP 102 may also transmit an FD-IMTF 310 to a group of STAs 104 to trigger a sequence of FD-IRFs 320 in a manner similar to that shown in Figure 5.

[0061] In some examples, the AP 102 may use any of the above-described operations in combination. For example, the AP 102 may first transmit an FD-IMTF 310 for each STA 104 individually to provide each STA 104 with appropriate parameters for transmitting the FD-IRF 320 (e.g., as shown in FIG. 4). The AP 102 may then transmit an FD-IMTF 310 for a group of STAs 104 to respond sequentially (e.g., as shown in FIG. 5) or using MU UL multiplexing (e.g., as shown in FIG. 7).

[0062] Transmission of the FD-IMTF 310 by the AP 102 may be, for example, periodic, semi-periodic, event-based, intermittent, or a combination thereof (e.g., the FD-IMTF 310 may be transmitted periodically and in response to a detected device). Events that may cause the AP 102 to transmit the FD-IMTF 310 include, for example, changes in the basic service set (BSS) topology (e.g., the joining or leaving of a new STA 104, or other longer-term changes in the wireless network such as changes in distance, altitude, shadowing, or connectivity), STA association, STA mobility, or user activity (e.g., a traffic session being active or inactive).

[0063] In some examples, the CCA procedure preceding the transmission of the FD-IMTF 310 may depend on the medium access category assigned by the AP 102. For example, the AP 102 may assign the FD-IMTF 310 to a high priority category (e.g., a "priority access" category similar to beacon frames). Thus, when the AP 102 determines that the medium is idle, it may perform a short CCA for the duration of a point coordination function (PCF) interframe space (PIFS) before transmitting the FD-IMTF 310. In some examples, the AP 102 may assign the FD-IMTF 310 to the same access category as management frames or other data traffic of a periodic nature (e.g., voice data). In such a case, when the AP 102 determines that the medium is idle, it may perform a CCA for the duration of a corresponding arbitration interframe space (AIFS) followed by a randomly generated backoff window before transmitting the FD-IMTF 310. In some examples, the transmission of the FD-IMTF 310, the corresponding FD-IRF 320, and possibly the corresponding FD-IMRF may be contained within the duration of the TXOP of the PCF or Hybrid Coordination Function (HCF) (e.g., in IEEE 802.11e). In such cases, the time span of the potential interference measurement procedure, and possibly also the reporting procedure, may be ensured by the AP 102 by setting the Network Allocation Vector (NAV) of the Wi-Fi nodes in the neighboring service set to the end of the procedure.

[0064] Regardless of the type of FD-IMTF 310 from the AP 102 or how the responding FD-IRF 320 is triggered (e.g., as shown in FIG. 4, FIG. 5, FIG. 7, or a combination thereof), at the end of the trigger sequence, each STA 104 associated with the AP 102 separately reports potential interference measurements to the AP 102 using a reporting frame such as an FD-IMRF. The FD-IMTF 310 may include information that enables each STA 104 to report an FD-IMRF. For example, the FD-IMTF 310 may indicate an end time of the trigger sequence. The FD-IMRF may be automatically transmitted by each STA 104 following the indicated end of the trigger sequence. The FD-IMRF may also be transmitted in response to detection of an event, such as in response to a request from the AP 102.

[0065] In some examples, the CCA procedure preceding the transmission of the FD-IMRF may depend on the medium access category assigned by the AP 102. For example, the AP 102 may assign the FD-IMRF to a high priority category (e.g., a "priority access" category similar to a beacon frame). Thus, when the STA 104 determines that the medium is idle, it may perform a short CCA for a PIFS duration before transmitting the FD-IMRF. In some examples, the AP 102 may assign the FD-IMRF to the same access category as management frames or other data traffic of a periodic nature (e.g., voice data). In such a case, when the STA 104 determines that the medium is idle, it may perform a CCA for the duration of the corresponding AIFS followed by a randomly generated backoff window before transmitting the FD-IMRF.

[0066] The FD-IMTF 310 may also include information specifying how potential interference measurements should be reported to the AP 102. For example, the FD-IMTF 310 may indicate a tolerable interference threshold and / or a maximum number of tolerable interferers. The tolerable interference threshold indicates a received interference power level below which UL FD interference may be expected not to significantly interfere with DL reception. Tolerable interferers are STAs 104 that are sources of tolerable interference. Tolerable interference or tolerable interferers may also be referred to as acceptable interference or tolerable interferers. The STAs 104 may only report potential interference measurements that are below the tolerable interference threshold and / or may only report up to a maximum number of tolerable interferers. If the STAs 104 have not obtained any potential interference measurements (e.g., the STAs 104 have not encountered any potential interference caused by FD-IRF 320 transmissions by other STAs), the STAs 104 may report that all other STAs 104 are equally tolerable interferers. If the STAs 104 all obtain unacceptable potential interference measurements (e.g., the power levels of all interference measurements exceed an acceptable interference threshold), the STAs 104 may report that all other STAs 104 are unacceptable interferers, may provide a null report, or the STAs 104 may not provide a report to the AP 102.

[0067] FIG. 8 illustrates an example table showing potential interference information that may be included in the FD-IMRF. The example table shows potential interference measurements reported by STA1 104-1. The table entries are ordered from lowest potential interference measurement (i.e., lowest measured power) to highest potential interference measurement (i.e., highest measured power). The column "Total FD Interference" contains the cumulative potential interference measurements, starting with the lowest potential interference measurement and adding the next lowest potential interference measurement in each subsequent row. The column "FD Interference Source ID" contains an identifier for the source of potential interference added to each row. For example, in FIG. 8, I 5is the lowest potential interference measurement, with STA5 104-5 being the source, and I 6 is the second lowest potential interference measurement, originating from STA6 104-6.

[0068] Various formats may be used to report the potential interference measurements. For example, the report may include a cumulative potential interference measurement up to an acceptable interference threshold. 5 +I 6 is below the acceptable interference threshold, I 5 +I 6 +I 2 If is above the acceptable interference threshold, the FD-IMRF is I 5 +I 6 Only entries up to may be reported. The report may include only identifiers of the interferers (e.g., omitting the column "Total FD Interference"). Potential interference measurements may be reported individually rather than cumulatively. Other such variations may be possible, and the format of the report may be configurable (e.g., as specified by the AP 102 in the FD-IMTF 310).

[0069] The potential interference measurement reported by each STA 104 may be a measurement taken from the most recent round of the FD-IRF 320 (e.g., the most recent potential interference measurement overwrites previous measurements) or may be a running average of the most recent and one or more previous measurements (e.g., measurements averaged over a moving window of time or measurement instances). When the measured potential interference power is reported, quantization may be applied.

[0070] The AP 102 receives the FD-IMRF from each STA 104, decodes the FD-IMRF, and obtains potential interference information from the reports. The AP 102 uses the potential interference information contained in the FD-IMRF to determine, for a given DL receiving STA 104, which other STAs 104 (if any) are acceptable interferers for a simultaneous UL transmission. The potential interference information may be stored in the AP 102 in the form of a look-up table, for example, as shown in FIG. 9. The column "DL Rx STA" indicates the DL receiving STAs 104. The column "Acceptable FD Interferers" indicates any STAs 104 that may be selected for a simultaneous FD UL transmission for each DL receiving STA 104 shown in the left-most column. The STAs 104 shown under "Acceptable FD Interferers" are STAs 104 that potentially cause FD interference (if any) below an acceptable interference threshold, as determined based on potential interference measurements obtained by the DL receiving STAs 104. Thus, the stored potential interference information can indicate which STAs (if any) are acceptable UL transmitting STAs 104 that may be selected by the AP 102 for a simultaneous FD UL transmission during an ongoing DL transmission by a given DL receiving STA 104, and the stored potential interference information can also indicate which STAs (if any) are acceptable DL receiving STAs 104 that may be selected by the AP 102 for a simultaneous FD DL transmission during an ongoing UL transmission by a given UL transmitting STA 104.

[0071] In the example shown in Figure 9, when STA1 104-1 is the DL receiving STA, STA5 104-5 and STA6 104-6 are both tolerable interferers, meaning that simultaneous FD UL transmissions from STA5 104-5 and / or STA6 104-6 would not cause unacceptable interference at STA1 104-1. Similarly, when STA2 104-2 is the DL receiving STA, STA3 104-3 is a tolerable interferer. When STA6 104-6 is the DL receiving STA, the indicated tolerable interferer is null, meaning that there are no tolerable interferers and simultaneous FD UL transmissions that do not cause unacceptable interference at STA6 104-6 are not possible. When there are two or more acceptable interference sources indicated for a given DL receiving STA 104, the acceptable interference sources may be sorted in order from lowest potential interference measurement to highest potential interference measurement, so that the AP 102 can preferentially select the interference source that causes the lowest potential interference measurement for UL transmissions, or the interference source for which transmission is prioritized in terms of quality of service requirements, such as maximum latency / jitter or minimum rate requirements.

[0072] For a DL transmission initiated or scheduled for a given DL receiving STA 104, the AP 102 can use the potential interference information to select one or more STAs 104 for simultaneous FD UL transmission such that the selected STAs 104 are expected to cause tolerable interference at the DL receiving STA 104.

[0073] Although the example table of FIG. 9 lists acceptable interference sources for a given DL receiving STA, the information contained in this lookup table may be used by the AP 102 to select DL receiving STAs 104 for simultaneous DL transmission with an initiated or scheduled UL transmission. For example, if a UL transmission is scheduled or initiated from STA5 104-5, the AP 102 may use a back lookup to identify STA1 104-1 as a possible DL receiving STA 104 for a simultaneous FD DL transmission. In some examples, instead of using a back lookup, the AP 102 may store a separate lookup table indicating possible DL receiving STAs for a given UL transmitting STA. In some examples, the AP 102 may only store a lookup table indicating possible DL receiving STAs for a given UL transmitting STA. The AP 102 may also store the potential interference information in any suitable non-table format.

[0074] In some examples, the potential interference information may also indicate a measured potential interference power for each identified acceptable interference source. Such information may be used by the AP to control UL / DL transmit power levels. For example, based on the potential interference information, the AP 102 may indicate an allowed FD UL transmit power level to mitigate interference due to simultaneous FD DL transmissions. The AP 102 may also control its own FD DL transmit power level to mitigate expected interference caused by simultaneous FD UL transmissions.

[0075] 10 is a flow chart illustrating an example method 1000 that may be performed by an AP 102. The method 1000 may be performed by the AP 102 to collect potential interference information from one or more associated STAs 104, for example, according to the operations described above with respect to FIGS.

[0076] At 1005, the AP 102 transmits a trigger frame (e.g., FD-IMTF 310). The trigger frame may be multicast to all associated STAs 104. The trigger frame causes at least a first intended STA 104 to start transmitting an UL reference frame (e.g., FD-IRF 320) to the AP. The trigger frame also causes at least one other second STA 104 to obtain potential interference measurements during UL transmissions by the first STA 104. As previously described, the trigger frame may include information identifying the intended STA 104, transmission parameters for response transmissions, and / or reporting parameters to be used to report potential interference measurements.

[0077] In some examples, the AP 102 can determine whether the FD-IRF 320 is received from the first intended STA 104. If the FD-IRF 320 is not received from the first intended STA 104, the AP 102 can retransmit the trigger frame, e.g., as described above, before or after transmitting the trigger frame to another STA. As described above, the AP 102 can further exclude any persistently unresponsive STAs 104 from the FD TXOP.

[0078] At 1010, the AP 102 receives a report frame (e.g., FD-IMRF) from at least the second STA 104. For example, the AP 102 may receive a respective report frame from each associated STA 104. The report frame includes information regarding potential interference measurements obtained by the second STA 104 indicating any potential interference encountered by the second STA 104 caused by the transmission of the UL reference frame from the first STA 104. The report frame may include the reported information according to any suitable format, such as the format described above with reference to FIG. 8.

[0079] Optionally, the AP 102 may store the potential interference information identified from the information collected from the reporting frames at 1015. The potential interference information may be stored according to any suitable format, such as the format described above with reference to FIG.

[0080] At 1020, using the information collected from the reporting frame, the AP 102 selects a UL transmitting STA for an FD UL transmission during a DL transmission to another DL receiving STA (e.g., a scheduled DL transmission or an already started DL transmission), or the AP 102 selects a DL receiving STA for an FD DL transmission during a UL transmission by another UL transmitting STA (e.g., a scheduled UL transmission or an already started UL transmission).

[0081] 11 is a flow chart illustrating an example method 1100 that may be performed by a STA 104 associated with an AP 102. The method 1100 may be performed by the STA 104 to obtain potential interference measurements, for example, according to the operations described above with respect to FIGS.

[0082] At 1105, the STA 104 receives a trigger frame (e.g., FD-IMTF 310) from the AP 102. The trigger frame causes the STA 104 to obtain potential interference measurements during a UL response transmission (e.g., a FD-IRF 320 transmission) by another STA 104. As previously described, the trigger frame may include information identifying the intended STA 104, transmission parameters for the response transmission, and / or reporting parameters to be used to report the potential interference measurements.

[0083] Optionally, if the trigger frame is intended to trigger a response transmission from the STA 104, at 1110 the STA 104 may transmit a UL response transmission to the AP 102 (e.g., according to any parameters indicated in the trigger frame).

[0084] At 1115 , the STA 104 obtains a potential interference measurement by measuring any potential interference caused by the UL response transmission by another STA 104 .

[0085] At 1120, the STA 104 transmits a report frame (e.g., FD-IMRF) containing information about the potential interference measurements to the AP 102. The transmission of the report frame may be according to any parameters indicated in the trigger frame. The STA 104 may attempt to transmit the report frame at the time indicated by the trigger frame (e.g., indicated by an end of sequence flag or by calculating the end of a response period according to a response sequence indicated in the trigger frame).

[0086] 11 is described above as illustrating a method for obtaining potential interference measurements by a STA 104. However, it should be appreciated that FIG. 11 may also illustrate a method for an intended responding STA 104 to transmit a response transmission (e.g., FD-IRF 320). For a responding STA 104, 1110 is not optional, but 1115 and 1120 are optional.

[0087] The above example describes a mechanism for the AP 102 to collect potential interference measurements in order for the AP 102 to manage FD communications. In some cases, the above example may be similarly implemented for STAs with FD capabilities (and other AP capabilities as needed, such as in the case of a STA with some base station capabilities as in an LTE-A repeater), e.g., an FD-capable STA may engage in STA-to-STA FD communications with two other STAs and manage the FD communications using the mechanisms described above. For example, a Group Owner (GO) STA in Wi-Fi Direct communications may facilitate peer-to-peer communications when the AP is absent, and thus a GO STA may implement some functions of an AP as described above.

[0088] Although this disclosure describes methods and processes having a particular order of steps, one or more steps of the methods and processes may be omitted or modified, if desired. One or more steps may be performed in an order other than the order in which they are described, if desired.

[0089] Although the present disclosure is described at least in part with respect to a method, those skilled in the art will understand that the present disclosure is also directed to various components for performing at least some of the aspects and features of the described method, by hardware components, software, or any combination of the two. Thus, the technical solutions of the present disclosure may be embodied in the form of a software product. A suitable software product may be stored in a pre-recorded storage device or other similar non-volatile or non-transitory computer-readable medium, including, for example, a DVD, a CD-ROM, a USB flash disk, a removable hard disk, or other storage medium. The software product includes instructions tangibly stored thereon that enable a processing device (e.g., a personal computer, a server, or a network device) to execute the method examples disclosed herein.

[0090] The present disclosure may be embodied in other specific forms without departing from the subject matter of the claims. The described exemplary embodiments should be considered in all respects as merely illustrative and not restrictive. Selected features from one or more of the above-described embodiments may be combined to create alternative embodiments not expressly described, and features suitable for such combinations are understood to be within the scope of the present disclosure.

[0091] All values ​​and subranges within the disclosed ranges are also disclosed. Also, while the systems, devices, and processes disclosed and illustrated herein may comprise a particular number of elements / components, the systems, devices, and assemblies may be modified to include additional or fewer such elements / components. For example, while any of the disclosed elements / components may be referred to in the singular, the embodiments disclosed herein may be modified to include a plurality of such elements / components. The subject matter described herein is intended to cover and embrace all appropriate modifications in technology. [Explanation of symbols]

[0092] 100 Systems 110 Downlink (DL) transmission 120 Uplink (UL) transmission 130 Interference 200 Processing System 202 Processing Device 204 Input / Output (I / O) Interface 206 Network Interface 208 Storage Unit 210 Memory 212 Bus 214 Input Devices 216 Output Devices 218 Antenna Array 310 FD Interferometry Trigger Frame (FD-IMTF) 320 FD Interferometric Reference Frame (FD-IRF) 330 Potential Interference Measurements

Claims

1. in response to receiving a trigger frame from an access point (AP), measuring, by a second station (STA), a signal strength of a first uplink (UL) reference frame during transmission of the first UL reference frame by a first STA to the AP immediately following a single interframe space (SIFS) from the end of the trigger frame to obtain a signal strength measurement; transmitting a report frame to the AP including information regarding the signal strength measurements; A method comprising:

2. Potential interference information determined from the information included in the report frame is stored in the AP, the potential interference information indicating the first STA and the second STA, a first FD UL signal from the first STA to the AP behaves as an interference signal with respect to a second DL signal to the second STA, and a first strength of the interference signal is lower than an acceptable threshold for the second STA; and receiving the second DL signal scheduled based on the reporting frame. The method of claim 1.

3. Potential interference information determined from the information included in the report frame is stored in the AP, the potential interference information indicating the first STA and the second STA, a first FD UL signal from the first STA to the AP behaves as an interference signal with respect to a second DL signal from the AP to the second STA, and a second strength of the interference signal is lower than a threshold at which simultaneous transmission of the first FD UL signal and the second DL signal is acceptable; receiving the second DL signal scheduled to overlap with transmission of the first FD UL signal based on the reporting frame; 3. The method according to claim 1 or 2.

4. The information regarding the signal strength measurements is: indicating a signal power of the first UL reference frame measured by the second STA; 4. The method according to any one of claims 1 to 3.

5. A step of receiving the trigger frame; obtaining an identifier of a source of the signal strength of the first UL reference frame measured by the second STA based on the trigger frame; including an identifier of the source in the information included in the reporting frame; Also includes 4. The method according to any one of claims 1 to 3.

6. The method of claim 4 , wherein the information included in the report frame does not include an identifier for any signal strength measurements within a defined acceptable interference threshold.

7. The method of claim 5, wherein the information included in the report frame does not include the signal power of the first UL reference frame measured by the second STA.

8. transmitting, by the second STA, a second UL reference frame to the AP in response to receiving the trigger frame from the AP.

8. The method of claim 1, further comprising:

9. 9. The method of claim 8, wherein the second UL reference frame is transmitted by the second STA contiguous with the first UL reference frame by the first STA.

10. The trigger frame: an identifier of at least the first STA; transmission parameters for transmitting the UL reference frame; reporting parameters for the reporting frame; The method according to any one of claims 1 to 9, wherein the method further comprises:

11. The transmission parameters are: an indicator of transmission power; an indicator of the time-frequency pattern of the reference symbols; an indicator of the precoding to be used; a transmission duration indicator; an indicator of the transmission resource to be used; The method of claim 10, comprising at least one of:

12. The reporting parameters are: an indicator of an acceptable interference threshold; an indicator of a maximum number of acceptable interference sources and an indicator of a time for transmitting said report frame; The method of claim 10, comprising at least one of:

13. A first station (STA), a communication interface for wireless communication with an access point (AP); The first STA, in response to receiving a trigger frame from the AP, measuring a signal strength of an uplink (UL) reference frame during a transmission of a first UL reference frame by a second STA to the AP immediately following a single interframe space (SIFS) from a time when the trigger frame ends to obtain a signal strength measurement; causing the AP to transmit a report frame containing information regarding the signal strength measurement value; a processor configured to execute instructions; A first STA comprising:

14. Potential interference information determined from the information included in the report frame is stored in the AP, the potential interference information indicating the second STA and the first STA, a second FD UL signal from the second STA to the AP behaves as an interference signal with respect to a first DL signal to the first STA, and a first strength of the interference signal is lower than an acceptable threshold for the first STA; The processor is configured to execute instructions to cause the first STA to further receive the first DL signal scheduled based on the reporting frame. The first STA according to claim 13.

15. Potential interference information determined from the information included in the report frame is stored in the AP, the potential interference information indicating the second STA and the first STA, and a first FD UL signal from the second STA to the AP behaves as an interference signal with respect to a second DL signal to the first STA; The processor is configured to execute instructions to cause the first STA to receive the second DL signal scheduled to overlap with a transmission of the first FD UL signal based on the reporting frame. A first STA according to claim 13 or 14.

16. The information regarding the signal strength measurements is: indicating a signal power of the first UL reference frame measured by the first STA; A first STA according to any one of claims 13 to 15.

17. The processor, in the first STA, receiving the trigger frame; obtaining an identifier of a source of the signal strength of the first UL reference frame measured by the second STA based on the trigger frame; causing the information included in the report frame to include an identifier of the source. Configured to execute instructions A first STA according to any one of claims 13 to 15.

18. The first STA of claim 16, wherein the information included in the report frame does not include an identifier for any signal strength measurement within a defined acceptable interference threshold.

19. A first STA as described in claim 17, wherein the information included in the report frame does not include the signal power of the second UL reference frame measured by the first STA.

20. The first STA of claim 18, wherein the processor is further configured to execute instructions to cause the first STA to transmit a second UL reference frame to the AP in response to receiving the trigger frame from the AP.

21. 21. The first STA of claim 20, wherein the second UL reference frame is transmitted by the second STA contiguous with the first UL reference frame by the first STA.

22. A first STA according to any one of claims 13 to 21, wherein the trigger frame indicates at least one of an identifier of the first STA, transmission parameters for transmitting the UL reference frame, or reporting parameters for the report frame.

23. The transmission parameters are: an indicator of transmission power; an indicator of the time-frequency pattern of the reference symbols; an indicator of the precoding to be used; a transmission duration indicator; an indicator of the transmission resource to be used; The first STA according to claim 22, comprising at least one of:

24. The reporting parameters are: an indicator of an acceptable interference threshold; an indicator of the maximum number of acceptable interferers; an indicator of a time for transmitting the report frame; and The first STA according to claim 22, comprising at least one of:

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