Patent Description:
Embodiments of the present invention generally relate to the field of wireless communications. More specifically, embodiments of the present invention relate to a method, an apparatus, and a computer-readable storage medium for mitigating signal interference between devices in close physical proximity in a wireless communication network.

Document <CIT> discloses a method according to the precharacterizing part of independent claim <NUM>. Such a method is also disclosed in each of the documents <CIT> and <CIT>.

Many modern electronic devices send and receive data with other electronic devices wirelessly using Wi-Fi, and several devices may be communicating over bands or channels that are close in frequency within the same physical location, such as a home, office, or library. Often these devices, including smartphones, tablets, and laptop computers, are connected to the same wireless access point (AP). When two nearby devices associated with same AP are operated on bands that are close in frequency, the transmitting wireless station (STA) can interfere with another STA that is receiving data. The signal interference (e.g., alternative adjacent channel interference (AACI)) may decrease the RX sensitivity of the receiving device. This negative impact on sensitivity is referred to as "desense" and typically occurs when two operating bands are close in frequency and have inadequate isolation and filtering to prevent energy leakage from sidebands.

The unwanted desense can be caused by different wireless devices that are operating close to each other (inter-device desense) or different wireless stations (STAs) of the same multi-band device (in-device desense). The defense problem is magnified when the STAs are close in physical proximity to each other but far away from the AP. In general, a higher ISR (=I/S) causes more significant desense.

What is needed is a communication approach to wireless transmission that coordinates transmissions between STAs and an AP to prevent or mitigate interference between wireless stations associated with the same access point that are in relatively close physical proximity. Accordingly, embodiments of the present invention substantially mitigate or prevent in-device and inter-device interference (e.g., AACI) by grouping wireless stations associated with an AP according to their estimated physical proximity with each other. The transmissions to/from STAs within a group can be coordinated so that a wireless transmission does not interfere with the wireless reception of another STA within the same group. In this way, desense is avoided and the wireless reception can be performed efficiently. A method, a wireless access point, and a non-transitory computer-readable storage medium according to the invention are defined in the independent claims. The dependent claims define preferred embodiments thereof.

The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention:.

Reference will now be made in detail to several embodiments. While the subject matter will be described in conjunction with the alternative embodiments, it will be understood that they are not intended to limit the claimed subject matter to these embodiments. The claimed subject matter is defined only by the appended claims.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. However, it will be recognized by one skilled in the art that embodiments may be practiced without these specific details or with equivalents thereof. In other instances, well-known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects and features of the subject matter.

Portions of the detailed description that follow are presented and discussed in terms of a method. Although steps and sequencing thereof are disclosed in a figure herein (e.g., <FIG>) describing the operations of this method, such steps and sequencing are exemplary. Embodiments are well suited to performing various other steps or variations of the steps recited in the flowchart of the figure herein, and in a sequence other than that depicted and described herein.

Some portions of the detailed description are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed on computer memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, computer-executed step, logic block, process, etc., is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system.

Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout, discussions utilizing terms such as "accessing," "configuring," "coordinating," "storing," "transmitting," "authenticating," "identifying," "requesting," "reporting," "determining," or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

Some embodiments may be described in the general context of computer-executable instructions, such as program modules, executed by one or more computers or other devices.

Embodiments of the present invention substantially mitigate or prevent in-device and inter-device signal interference (e.g., AACI) by advantageously grouping wireless stations associated with an AP according to their estimated physical proximity with each other. The STAs within a group can be coordinated so that a wireless transmission does not interfere with a contemporaneous wireless reception of another STA within the same group. In this way, the unwanted effects of desense are avoided and the wireless reception can be performed efficiently.

<FIG> is a diagram of an exemplary wireless network <NUM> including wireless access point <NUM> associated with STA1 (<NUM>) and STA2 (<NUM>). STA1 and STA2 transmit over different wireless bands that are close in frequency, and STA1 and STA2 are relatively close to each other geographically (e.g., within <NUM> meters). Accordingly, when one of the STAs transmits data wirelessly while the other STA is receiving data wirelessly, or begins transmitting data wirelessly while the other STA is already receiving data wirelessly, significant signal interference between the STAs (e.g., AACI) can cause signal degradation. Specifically, the STA that is receiving data will experience a degraded signal (desense) and the transmission will therefore be less efficient. The AACI depicted between band1 and band2 in the example of <FIG> is inter-device interference caused by distinct wireless devices.

<FIG> is a diagram of an exemplary wireless network <NUM> including a wireless device <NUM> experiencing in-device AACI while simultaneously transmitting and receiving data. Wireless device <NUM> may be any one of a number of different well-known components including a wireless smartphone, laptop, or tablet for example, and includes a first wireless station <NUM> and a second wireless station <NUM> capable of operation over different wireless bands.

STA <NUM> and a STA <NUM> can be configured to operate simultaneously over wireless bands that are close or similar in frequency. Accordingly, when one of the STAs transmits data wirelessly while the other STA is receiving data wirelessly, or begins transmitting data wirelessly while the other STA is already receiving data wirelessly, significant signal interference between the STAs (e.g., AACI) can cause signal degradation. Specifically, the STA that is receiving data will experience a degraded signal and the transmission will therefore be less efficient. The AACI depicted between band1 and band2 in the example of <FIG> is in-device interference caused by different wireless stations of the same wireless device (e.g., a dual or multi-band wireless device).

<FIG> and <FIG> are diagrams of an exemplary wireless network <NUM> for coordinating transmission between wireless devices grouped based on a received signal strength indicator (RSSI) threshold according to embodiments of the present invention. In the example of <FIG>, AP <NUM> is associated with wireless devices STA1 (<NUM>) and STA2 (<NUM>). STA2 may experience desense when receiving data from wireless AP <NUM> if STA1 begins transmitting to AP <NUM>. For example, SAT <NUM> may experience AACI that is magnified when STA1 and STA2 are in close physical proximity and/or are using bands that are close in frequency. Accordingly, to prevent interference between STA1 and STA2, the STAs associated with AP <NUM> can detect RSSI and report the detected RSSI to AP <NUM> for identifying potential interference between the STAs.

One example is now described. As depicted in <FIG>, STA1 transmits data to AP <NUM> causing interference that is detected by STA2. STA2 determines if the received interference is from an STA associated with the same AP (i.e. AP <NUM>) as STA2. If the STA is not associated with the same AP (i.e. AP <NUM>) as STA2, the process ends. If STA2 determines that the STA is associated with AP <NUM>, STA2 then determines if the received RSSI from the STA is larger than a predetermined RSSI threshold. As depicted in <FIG>, if the RSSI received from STA <NUM> is larger than the RSSI threshold, STA2 reports information associated with STA1 ("transmission information") to AP <NUM>. The information reported by STA2 may include the interference source (e.g., STA ID, MAC address, etc.), the band info (e.g., operating frequency), the received RSSI, etc. Because STA1 and STA2 are associated with AP <NUM> and the received RSSI is above the threshold, AP <NUM> advantageously groups STA1 and STA2 to coordinate wireless operations and advantageously prevent interference between the devices.

<FIG> depicts an exemplary wireless network <NUM> for coordinating transmission between wireless devices grouped according to RSSI, pathloss (PL), and/or angle of arrival (AOA) according to embodiments of the present invention. In the example of <FIG>, AP <NUM> groups associated STAs according to metrics measured at the AP-side. For example, AP <NUM> measures RSSI when receiving data from STA1 (<NUM>), STA2 (<NUM>), and STA3 (<NUM>) and calculates path loss information according to the transmission power (TxPwr) of an STA indicated in a trigger-based UL packet. AP <NUM> can also calculate the angle of arrival between AP <NUM> and an STA and estimate the physical proximity of the devices relative to each other according to the PL and the AOA. The AOA can be determined according to channel state information (CSI) of the bands and the antenna pattern of AP <NUM>, for example.

AP <NUM> groups the STAs for coordinating transmissions of the STAs to prevent or mitigate signal interference between the group of STAs based on the metrics measured by the AP. For example, if STA1 and STA2 are determined to be in close physical proximity (e.g., within <NUM> meters) according to the calculated PL and AOA, STA1 and STA2 can be grouped together by AP <NUM> to coordinate transmissions between the devices. In the example of <FIG>, AP <NUM> calculates the PL and AOA associated with STA3 and does not group STA3 with STA1 and STA2 because the PL and AOA information for STA3 are substantially different.

<FIG> depict an exemplary wireless network <NUM> for coordinating transmissions between wireless devices grouped according to receiving failures that coincide with the transmission of an associated STA according to embodiments of the present invention. AP <NUM> can listen over nearby bands (e.g., band <NUM>) while transmitting data to a wireless station over band <NUM> to determine if the band is busy. As depicted in <FIG>, STA1 (<NUM>) is receiving a transmission from AP <NUM> over band <NUM> while STA2 (<NUM>) is transmitting UL data to AP <NUM> over band <NUM>. Accordingly, AP <NUM> identifies STA2 a potential source of interference to STA1 if transmissions of the devices transmitted in different directions overlap.

Continuing in <FIG>, if AP <NUM> does not receive an acknowledgement from STA1 (e.g., a block ack (BA)), AP <NUM> determines that STA1 and STA2 are likely relatively close to each other (e.g., within <NUM> meters). AP <NUM> can group STA1 and STA2 to coordinate transmissions of the devices for preventing or mitigating interference between the devices (e.g., AACI) after any number of receiving errors are detected.

As depicted in <FIG>, AP <NUM> detects overlapping transmissions. When AP <NUM> subsequently fails to receive a BA from STA2 while STA1 is transmitting, it is considered further evidence that STA1 and STA2 are in close physical proximity. In this case AP <NUM> will typically group STA1 and STA2 for coordinated transmission.

AP <NUM> may receive a BA from STA1 or STA2 indicating that some of the data transmitted by STA1 or STA2 was successfully received. In the case of a partial transmission failure, AP <NUM> can determine that STA1 and STA2 are in close physical proximity according to the BA and group the STAs for coordinated transmission.

After an AP defines groups of associated wireless stations according to estimated physical proximity, the AP can coordinate subsequent transmissions to prevent STAs in the same group from transmitting and receiving at the same time. For example, as depicted in <FIG>, AP <NUM> of exemplary wireless network <NUM> can use trigger frame (TR) <NUM> to solicit UL transmission <NUM> from the STAs to advantageously avoid simultaneous downlink (DL) and UL transmission within the same group according to embodiments of the present invention. AP <NUM> does not schedule a packet for transmission to STA2 that would be transmitted while STA1 is transmitting UL data in response to trigger frame <NUM>. In this way, signal interference between STA1 and STA2 is advantageously avoided.

<FIG> depicts an exemplary wireless network <NUM> including STAs in close proximity to each other that do not understand trigger frames (e.g., legacy devices) according to embodiments of the present invention. After AP <NUM> groups associated STAs ("STA groups") according to information collected from the STAs (e.g., RSSI), or according to information calculated by the AP (e.g., RSSI, PL, AOA), AP <NUM> coordinates transmissions between the STAs and the AP to prevent interference between the STAs. For example, as depicted in <FIG>, AP <NUM> can avoid scheduling transmissions to STA2 (<NUM>) while receiving UL data from STA1 to advantageously prevent interference between the STAs.

<FIG> is a flow chart of an exemplary sequence of computer implemented steps for automatically scheduling transmissions between a wireless access point and its associated wireless devices (STAs) to reduce and/or prevent signal interference between the wireless devices during simultaneous transmission and reception thereof.

At step <NUM>, the AP receives or determines transmission information associated with the STAs directly or indirectly. The direct transmission information may include the interference source (e.g., STA ID, MAC address, etc.), the band info (e.g., operating frequency), and/or the received RSSI. The direct transmission information can also be received from an STA associated with the AP and can include information pertaining to another associated STA that is suspected of being in close physical proximity to the reporting STA (e.g., based on RSSI). Indirect transmission information may include the receiving quality (e.g. information indicated in or derived from BA) and traffic patterns (e.g. indication of overlapping transmission and reception). Step <NUM> can also include receiving an acknowledgment (e.g., a BA or bitmap) to determine if devices are in close physical proximity according to the successful/unsuccessful transmissions indicated in the acknowledgment.

At step <NUM>, the AP assigns groups to associated STAs that are likely to cause signal interference with each other based on the transmission information. For example, associated STAs can be grouped according to their estimated physical proximity with other STAs in the group. According to some embodiments, STAs that are estimated to be within approximately <NUM> meters are grouped together. Step <NUM> can include grouping STAs according to direct information received from the STAs or metrics calculated by the AP, such as PL, AOA, and/or RSSI as well as indirect information, for example.

At step <NUM>, the AP schedules transmissions with the STAs so that simultaneous transmission and reception over bands close in frequency within the group of STAs is avoided. Step <NUM> includes transmitting trigger frames soliciting uplink transmission from an STA, according to some embodiments. Accordingly, signal interference between STAs within the group is avoided and transmissions between the AP and the STAs are performed efficiently and without reception errors due to desense.

<FIG> depicts an exemplary wireless device <NUM> upon which embodiments of the present invention can be implemented. Embodiments of the present invention automatically transmit and/or schedule to transmit data between a wireless access point and a group of associated wireless devices (STAs) in a manner that advantageously prevents interference between the devices caused by simultaneous transmission and reception over bands close in frequency (AACI). The following discussion describes one such exemplary electronic system or computer system that can be used as a platform for implementing embodiments of the present invention. The exemplary computer system <NUM> can be a wireless access point or a wireless station, for example.

The wireless device <NUM> includes a processor <NUM> for running software applications and optionally an operating system. Memory <NUM> can include read-only memory and/or random access memory, for example, to store applications and data (e.g., tables of index values) for use by the processor <NUM> and data received or transmitted by transceivers <NUM>, <NUM>, and <NUM> over different wireless links. The wireless device <NUM> can include fewer or more transceivers according to some embodiments. The transceivers <NUM>, <NUM>, <NUM> communicate with other electronic devices over a wireless network (e.g., WLAN) and typically operates according to IEEE standards (e.g., IEEE <NUM>. 11ax, IEEE <NUM>. 11ay, IEEE <NUM>. 11be, etc.).

Claim 1:
A method of transmitting data in a wireless network performed by a wireless access point, in the following also referred to as AP, the method comprising:
determining that a first wireless station, in the following also referred to as STA, and a second STA are associated with the AP (<NUM>);
creating an STA group by grouping the first STA and the second STA (<NUM>); and
coordinating transmissions of the first STA and the second STA to avoid simultaneous transmission and reception of STAs in the STA group (<NUM>);
characterized by:
measuring a first received signal strength indicator, in the following also referred to as RSSI, of a data transmission received by the AP from the first STA:
calculating first path loss information based on the first RSSI;
measuring a second RSSI of a data transmission received by the AP from the second STA; and
calculating second path loss information based on the second RSSI, wherein the grouping the first STA and the second STA is performed according to the first and second path loss information.