Differential management power

Abstract

An electronic device (such as an access point) that dynamically adjusts transmit power in a wireless local area network (WLAN) is described. This electronic device may include an interface circuit that dynamically adjusts the transmit power. Notably, the electronic device may dynamically adjust the transmit power based at least in part on a type of packet. For example, a management packet may have a lower transmit power than a packet having an MCS rate greater than a predefined threshold. Alternatively or additionally, the electronic device may dynamically adjust the transmit power based at least in part on an MCS rate of the packet, where a given packet having a lower MCS rate may have a lower transmit power.

Description

DIFFERENTIAL MANAGEMENT POWERFIELD

[0001] The described embodiments relate to techniques for power management.BACKGROUND

[0002] Many electronic devices are capable of wirelessly communicating with other electronic devices. In particular, these electronic devices can include a networking subsystem that implements a network interface for: a cellular network (UMTS, LTE, etc ), a wireless local area network (e g., a wireless network such as described in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard or Bluetooth from the Bluetooth Special Interest Group of Kirkland, Washington), and / or another type of wireless network. For example, many electronic devices communicate with each other via wireless local area networks (WLANs) using an IEEE 802.11 -compatible communication protocol (which is sometimes collectively referred to as ‘Wi-Fi’). In a typical deployment, a Wi-Fi-based WLAN includes one or more access points (or basic service sets or BSSs) that communicate wirelessly with each other and with other electronic devices using Wi-Fi, and that provide access to another network (such as the Internet) via IEEE 802.3 (which is sometimes referred to as ‘Ethernet’).

[0003] One challenge in WLANs is power control. For example, dense networks often pose challenges for power control. In principle, transmit power control allows an access point to: reduce or manage interference with other proximate electronic devices; encourage aggressive roaming; and / or provide a frequency regulation (FR) request. In practice, transmit power control can result in coverage holes and lower throughput performance. For example, an access point may attempt to reduce interference to its neighboring access points and the clients served by those access points by reducing its transmit power. In doing so, the access point may reduce transmit power so much that it creates a coverage hole in the WLAN. In another example, the access may decrease its transmit power in attempt to reduce interference to neighboring access points and in the process the lowered transmit power level may cause lower throughput at the center of its own coverage area. In this example, the tuning of the access point has traded optimal throughput for close range clients for less interference to electronic devices in neighboring cells.SUMMARY

[0004] An electronic device (such as an access point) that dynamically adjusts transmit power in a WLAN is described. This electronic device may include an interface circuit that dynamically adjusts the transmit power. Notably, the electronic device may dynamically adjust the transmit power based at least in part on a type of packet. For example, a management packet may have a lower transmit power than a packet having an MCS rate greater than a predefined threshold. Alternatively or additionally, the electronic device may dynamically adjust the transmit power based at least in part on an MCS rate of the packet, where a given packet having a lower MCS rate may have a lower transmit power.

[0005] Moreover, a first packet having MCS 3 may have a 4 dB range advantage over a second packet having MCS 4. Consequently, the transmit power of the first packet may be reduced by 2 dB, so that the range advantage is reduced to 2 dB.

[0006] Another embodiment provides the second electronic device that performs counterpart operations to at least some of the aforementioned operations of the electronic device.

[0007] Another embodiment provides the computer system (such as a cloud-based computer system) that dynamically determines the transmit power of the electronic device.

[0008] Another embodiment provides a system that includes the electronic device and / or the computer system.

[0009] Another embodiment provides a computer-readable storage medium with program instructions for use with one of the aforementioned components. When executed by the component, the program instructions cause the component to perform at least some of the aforementioned operations in one or more of the preceding embodiments.

[0010] Another embodiment provides a method, which may be performed by one of the aforementioned components. This method includes at least some of the aforementioned operations in one or more of the preceding embodiments.

[0011] This Summary is provided for purposes of illustrating some exemplary embodiments, so as to provide a basic understanding of some aspects of the subject matter described herein. Accordingly, it will be appreciated that the above-described features are examples and should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages ofthe subject matter described herein will become apparent from the following Detailed Description, Figures, and Claims.BRIEF DESCRIPTION OF THE FIGURES

[0012] FIG. l is a block diagram illustrating an example of communication among electronic devices in accordance with an embodiment of the present disclosure.

[0013] FIG. 2 is a flow diagram illustrating an example of a method for dynamically adjusting transmit power using an electronic device in FIG. 1 in accordance with an embodiment of the present disclosure.

[0014] FIGs. 3A-C are drawings illustrating examples of service regions associated with different access points in accordance with an embodiment of the present disclosure.

[0015] FIGs. 4A-C are drawings illustrating examples of modulation coding scheme (MCS) rate as a function of range (in dB) associated with an electronic device in FIG. 1 in accordance with an embodiment of the present disclosure.

[0016] FIGs. 5A and 5B are drawings illustrating examples of MCS rate as a function from the distance or range to an electronic device in FIG. 1 in accordance with an embodiment of the present disclosure.

[0017] FIG. 6 is a block diagram illustrating an example of an electronic device in accordance with an embodiment of the present disclosure.

[0018] Note that like reference numerals refer to corresponding parts throughout the drawings. Moreover, multiple instances of the same part are designated by a common prefix separated from an instance number by a dash.DETAILED DESCRIPTION

[0019] An electronic device (such as an access point) that dynamically adjusts transmit power in a WLAN is described. This electronic device may include an interface circuit that dynamically adjusts the transmit power. Notably, the electronic device may dynamically adjust the transmit power based at least in part on a type of packet. For example, a management packet may have a lower transmit power than a packet having an MCS rate greater than a predefined threshold. Alternatively or additionally, the electronic device may dynamically adjust the transmit power based at least in part on an MCS rate of the packet, where a given packet having a lower MCS rate may have a lower transmit power.

[0020] By dynamically adjusting the transmit power, these power-management techniques may reduce interference between electronic devices (such as neighboringaccess points) in a WLAN. Moreover, the power-management techniques may reduce sticky clients that do not transition to an access point with superior or improved communication performance in a WLAN. Furthermore, these enhanced powermanagement techniques may increase the throughput of even those users who are connected to the closest and ’best’ access point. Consequently, the power-management techniques may reduce frustration of users and network operators or network administrators, and may improve the user experience when using in the WLAN and, more generally, a network that includes the WLAN.

[0021] In the discussion that follows, electronic devices or components in a system communicate packets in accordance with a wireless communication protocol, such as: a wireless communication protocol that is compatible with an IEEE 802.11 standard (which is sometimes referred to as ‘Wi-Fi®,’ from the Wi-Fi Alliance of Austin, Texas), Bluetooth, a cellular-telephone network or data network communication protocol (such as a third generation or 3G communication protocol, a fourth generation or 4G communication protocol, e.g., Long Term Evolution or LTE (from the 3rd Generation Partnership Project of Sophia Antipolis, Valbonne, France), LTE Advanced or LTE- A, a fifth generation or 5G communication protocol, or other present or future developed advanced cellular communication protocol), and / or another type of wireless interface (such as another wireless-local-area-network interface). For example, an IEEE 802.11 standard may include one or more of: IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11-2007, IEEE 802.11n, IEEE 802.11-2012, IEEE 802.11-2016, IEEE 802.1 lac, IEEE 802.1 lax, IEEE 802.11ba, IEEE 802.11be, or other present or future developed IEEE 802.11 technologies. Moreover, an access point, a radio node, a base station or a switch in the wireless network may communicate with a local or remotely located computer (such as a controller) using a wired communication protocol, such as a wired communication protocol that is compatible with an IEEE 802.3 standard (which is sometimes referred to as ‘Ethernet’), e.g., an Ethernet II standard. However, a wide variety of communication protocols may be used in the system, including wired and / or wireless communication. In the discussion that follows, Wi-Fi, LTE and Ethernet are used as illustrative examples.

[0022] We now describe some embodiments of the power-management techniques. FIG. 1 presents a block diagram illustrating an example of communication in an environment 106 with one or more electronic devices 110 (such as cellular telephones, portable electronic devices, stations or clients, another type of electronic device, etc.,which are sometimes referred to as ‘end devices’) via a cellular-telephone network 114 (which may include a base station 108), one or more access points 116 (which may communicate using Wi-Fi) in a WLAN and / or one or more radio nodes 118 (which may communicate using LTE) in a small-scale network (such as a small cell). For example, the one or more radio nodes 118 may include: an Evolved Node B (eNodeB), a Universal Mobile Telecommunications System (UMTS) NodeB and radio network controller (RNC), a New Radio (NR) gNB or gNodeB (which communicates with a network with a cellular-telephone communication protocol that is other than LTE), etc. In the discussion that follows, an access point, a radio node or a base station are sometimes referred to generically as a ‘communication device.’ Moreover, as noted previously, one or more base stations (such as base station 108), access points 116, and / or radio nodes 118 may be included in one or more wireless networks, such as: a WLAN, a small cell, and / or a cellular-telephone network. In some embodiments, access points 116 may include a physical access point and / or a virtual access point that is implemented in software in an environment of an electronic device or a computer.

[0023] Note that access points 116 and / or radio nodes 118 may communicate with each other, computer 112 (which may be a cloud-based controller that manages and / or configures access points 116, radio nodes 118 and / or switch 128, or that provides cloudbased storage and / or analytical services) and / or authentication computer 130 (such as a RADIUS server and / or an AAA server) using a wired communication protocol (such as Ethernet) via network 120 and / or 122. Note that networks 120 and 122 may be the same or different networks. For example, networks 120 and / or 122 may an LAN, an intra-net or the Internet. In some embodiments, network 120 may include one or more routers and / or switches (such as switch 128).

[0024] As described further below with reference to FIG. 6, electronic devices 110, computer 112, access points 116, radio nodes 118, switch 128 and authentication computer 130 may include subsystems, such as a networking subsystem, a memory subsystem and a processor subsystem. In addition, electronic devices 110, access points 116 and radio nodes 118 may include radios 124 in the networking subsystems. More generally, electronic devices 110, access points 116 and radio nodes 118 can include (or can be included within) any electronic devices with the networking subsystems that enable electronic devices 110, access points 116 and radio nodes 118 to wirelessly communicate with one or more other electronic devices. This wireless communication can comprise transmitting access on wireless channels to enable electronic devices tomake initial contact with or detect each other, followed by exchanging subsequent data / management frames (such as connection requests and responses) to establish a connection, configure security options, transmit and receive frames or packets via the connection, etc.

[0025] During the communication in FIG. 1, access points 116 and / or radio nodes 118 and electronic devices 110 may wired or wirelessly communicate while: transmitting access requests and receiving access responses on wireless channels, detecting one another by scanning wireless channels, establishing connections (for example, by transmitting connection requests and receiving connection responses), and / or transmitting and receiving frames or packets (which may include information as payloads).

[0026] As can be seen in FIG. 1, wireless signals 126 (represented by a jagged line) may be transmitted by radios 124 in, e.g., access points 116 and / or radio nodes 118 and electronic devices 110. For example, radio 124-1 in access point 116-1 may transmit information (such as one or more packets or frames) using wireless signals 126. These wireless signals are received by radios 124 in one or more other electronic devices (such as radio 124-2 in electronic device 110-1). This may allow access point 116-1 to communicate information to other access points 116 and / or electronic device 110-1. Note that wireless signals 126 may convey one or more packets or frames.

[0027] In the described embodiments, processing a packet or a frame in access points 116 and / or radio nodes 118 and electronic devices 110 may include: receiving the wireless signals with the packet or the frame; decoding / extracting the packet or the frame from the received wireless signals to acquire the packet or the frame; and processing the packet or the frame to determine information contained in the payload of the packet or the frame.

[0028] Note that the wireless communication in FIG. 1 may be characterized by a variety of performance metrics, such as: a data rate for successful communication (which is sometimes referred to as ‘throughput’), an error rate (such as a retry or resend rate), a mean-square error of equalized signals relative to an equalization target, intersymbol interference, multipath interference, a signal-to-noise ratio, a width of an eye pattern, a ratio of number of bytes successfully communicated during a time interval (such as 1-10 s) to an estimated maximum number of bytes that can be communicated in the time interval (the latter of which is sometimes referred to as the ‘capacity’ of a communication channel or link), and / or a ratio of an actual data rate to an estimateddata rate (which is sometimes referred to as ‘utilization’). While instances of radios 124 are shown in components in FIG. 1, one or more of these instances may be different from the other instances of radios 124.

[0029] In some embodiments, wireless communication between components in FIG. 1 uses one or more bands of frequencies, such as: 900 MHz, 2.4 GHz, 5 GHz, 6 GHz, 60 GHz, the Citizens Broadband Radio Spectrum or CBRS (e g., a frequency band near 3.5 GHz), and / or a band of frequencies used by LTE or another cellular- telephone communication protocol or a data communication protocol. Note that the communication between electronic devices may use multi-user transmission (such as orthogonal frequency division multiple access or OFDMA).

[0030] Although we describe the network environment shown in FIG. 1 as an example, in alternative embodiments, different numbers or types of electronic devices may be present. For example, some embodiments comprise more or fewer electronic devices. As another example, in another embodiment, different electronic devices are transmitting and / or receiving packets or frames.

[0031] As discussed previously, it may be difficult to adjust the transmit power of an electronic device (such as access point 116-1) in a WLAN or a network. In order to address this problem, in the disclosed power-management techniques access point 116- 1 may dynamically adjust transmit power in a WLAN. Notably, access point 116-1 may dynamically adjust the transmit power based at least in part on a type of packet that is transmitted by access point 116-1. For example, a management packet may have a lower transmit power than a packet having an MCS rate greater than a predefined threshold (such as MCS 5, MCS 8 or MCS 11. Alternatively or additionally, access point 116-1 may dynamically adjust the transmit power based at least in part on an MCS rate of the packet, where a given packet having a lower MCS rate may have a lower transmit power.

[0032] In these ways, the power-management techniques may provide reduced transmit power outside of a desired cell edge between the coverage regions of access point 116-1, which may reduce interference with other access points 116 and possible sticky clients (such as electronic device 110-1). Consequently, the power-management techniques may improve the user experience when using electronic device 110-1, access point 116-1 and communicating via the WLAN or a network that includes the WLAN.

[0033] While the preceding discussion illustrated the power-management techniques with communication between access point 116-1 (and, more generally, a computer network device) and electronic device 110-1, in other embodiments this communication may be mediated by one or more other components and / or may involve communication with the one or more other components.

[0034] We now describe embodiments of the method. FIG. 2 presents a flow diagram illustrating an example of a method 200 for dynamically adjusting transmit power in a WLAN, which may be performed by an electronic device, such as one of access points 116 or one of radio nodes 118 in FIG. 1. During operation, the electronic device may dynamically adjust the transmit power based at least in part on a type of packet (operation 210). For example, a management packet may have a lower transmit power than a packet having an MCS rate greater than a predefined threshold. Alternatively or additionally, the electronic device may dynamically adjust the transmit power based at least in part on an MCS rate of the packet (operation 212), where a given packet having a lower MCS rate may have a lower transmit power.

[0035] In some embodiments of method 200, there may be additional or fewer operations. Furthermore, the order of the operations may be changed, and / or two or more operations may be combined into a single operation.

[0036] We now further describe the power-management techniques. FIGs. 3A-C provide drawings illustrating the service regions associated with different access points. Notably, as shown in FIG. 3A, a sparse network may have good transitions from one basic service set identifier (BSSID) to another. In particular, in a central region of service associated with a first access point, the MCS may be greater than or equal to MCS 8, while in a transition region between the first access point and the second access point, the MCS may be less than or equal to MCS 5. Consequently, when an electronic device moves into the transition region between the first access point and the second access point (while the electronic device is currently associated with the first access point), the electronic device may receive, from the first access point, a BSS transition recommendation to transition to a second access point. Then, the electronic device may accept the BSS transition recommendation, and may transition to a different BSSID associated with the second access point. Alternatively the client may transition to a new access point by tracking the transmit power level of the management packets (such as beacons) that it receives from the first access point. When the transmit power ofthese packets drops below a certain threshold, the client may scan for other neighboring access points and smoothly transitions to the second access point.

[0037] Moreover, as shown in FIG. 3B, in a dense network with sparse settings, the MCS in the transition region between the first access point and the second access point, the MCS may be MCS 8 or MCS 5. Thus, instead of receiving, from the first access point, a BSS transition recommendation to the second access point, the electronic device may receive poorer communication performance (such as MCS 5, instead of MCS 8), while remaining associated with the first access point. Alternatively, a client tracking management packet transmit power in a dense network with sparse settings will not optimally transition to a neighboring access point. This electronic device will receive poorer communication performance (such as MCS 5, instead of MCS 8), while remaining associated with the first access point

[0038] Furthermore, as shown in FIG. 3C, in the disclosed power-management techniques a dense network may have an aggressive power drop as an electronic device moves from a center of a region associated with the BSSID of the first access point into the transition region between the first access point and the second access point. This may allow the first access point to provide an MCS greater than or equal to 8 in the center of the region, and to rapidly transition the electronic device to the second electronic device (by providing a BSS transition recommendation) when the electronic device moves into the transition region between the first access point and the second access point. Alternatively, the client will examine the weaker management packets in order to decide when to transition away from the current access point and will rapidly transition on its own at an improved transition point.

[0039] The power-management techniques are further illustrated in FIG. 4A-C. Notably, FIG. 4A provides a drawing illustrating MCS rate as a function of range (in dB) associated with an access point. In FIG. 4A, the transmit power is selected so that the MCS rate slowly decreases across the designated edge of a service area associated with the access point (which is sometimes referred to as a ‘designated cell edge’). However, as a consequence, there may be extra interference and possibly sticky clients that do not transition to associate with another access point when the clients move outside of the designated cell edge.

[0040] In FIG. 4A, typically, a high MCS may transmit at lower transmit powers than management packets. These lower transmit powers for high MCS packets are used because high MCS packets usually require a clean signal with a low EVM. Low EVMis difficult to achieve at high transmit powers and so the transmit power is decreased to meet the required EVM specs.

[0041] Alternatively, as shown in FIG. 4B, capping the transmit power for all packets transmitted from the access point may effectively lower transmit power for all clients whatever their distance from the access point. This approach may reduce the interference and possibly sticky clients outside of the designated cell edge. However, the communication performance at distances from the access points inside of the designated cell edge may be reduced. Note that in the power-management technique shown in FIG. 4B, when the transmit power is only slightly capped, the high MCS rates may be unaffected because their EVM constraints dictate an even lower transmit power than the cap. However, as the transmit power cap becomes more aggressive, even the transmit powers of the highest MCSs will be affected by the cap

[0042] Furthermore, as shown in FIG. 4C, in the disclosed power-management techniques, the transmit power may be maintained at path losses from the access point that are inside of the designated cell edge, but may be reduced at greater path losses outside of the designated cell edge. Alternatively, in some embodiments, the access point may implement a rubric in which certain high MCS rates are considered to be inside the designated cell edge and any lower MCS rates are considered to be outside the cell edge and their transmit power may be lowered. This approach may reduce interference and possibly sticky clients outside of the designated cell edge. For example, an otherwise sticky client may be encouraged to transition to a different BSSID. Note that in the disclosed power-management techniques, management packets (which have a lower data rate) may be transmitted at lower power than high MCS packets.

[0043] Note that a ‘high MCS’ may depend on the density of a network (e g., of the density of the access points). For example, as shown in FIG. 5 A, which presents a drawing illustrating MCS as a function from the distance or range to an access point, the MCS may be between MCS 5-9 if the network is capacity based. However, as shown in FIG. 5B, which presents a drawing illustrating MCS as a function from the distance or range to an access point, the MCS may be greater than a MCS 8 in a very- dense network.

[0044] Moreover, in the disclosed communication techniques, there may be at least some overlap between cells (or the regions associated with particular access points), so that a client is not dropped as it moves away from a given access point. For example,as the client moves outside of the coverage area of the given access point, the rate control of the given access point may decrease the MCS. The lower MCS may ensure that the client is not dropped.

[0045] In existing power-management techniques, different transmit power may be used for different MCS rates, and different transmit powers are often used because of hardware constraints. In the disclosed power-management techniques, a lower MCS may be transmitted at a lower transmit power. For example, in existing powermanagement techniques, a transmit power of 20 dBm may be used at MCS 11 and a transmit power of 25 dB may be used at MCS 5.

[0046] Alternatively, in the disclosed power-management techniques, the transmit power at an MCS 11 may be 20 dBm and the transmit power at an MCS 5 may be 19 dBm. While there may still be an EVM constraint, in the disclosed power management techniques the transmit power may not be increased at high MCS rates.

[0047] In the disclosed power-management techniques, note that the data rate and / or the number of streams associated with different MCS rates may impact the transmit power.

[0048] Thus, in the disclosed power-management techniques, the transmit power may decrease monotonically with decreasing MCS rate inside of the designated cell edge. Moreover, there may be a monotonic decrease in the transmit power from the designated cell edge. However, there may be a faster drop in the transmit power than is currently experienced by clients in existing power-management techniques.

[0049] Note that for Wi-Fi 5, the MCS rate is between MCS 0-9. Moreover, for Wi-Fi 6, the MCS rate is between MCS 0-11. Furthermore, for Wi-Fi 7, the MCS rate is between MCS 0-13.

[0050] In some embodiments, the disclosed power-management techniques may be implemented in a centralized or a distributed manner. For example, the transmit power and / or the MCS rate to use for a client of a given access point at a given distance or range from the given access point may be computed or determined by the given access point. Alternatively, the transmit power and / or the MCS rate to use for a client of a given access point at a given distance or range from the given access point may be computed or determined by a cloud-based computer system (which may be accessible via an intra-net and / or the Internet), which then communicates the computed or determined transmit power and / or the MCS rate to the given access point.

[0051] Moreover, the disclosed power-management techniques may be implemented using a pretrained model, such as a pretrained neural network or a pretrained machine-learning model (e g., a supervised-learning model) For example, for a given network having a given density, the pretrained neural network may use a range to a client as an input and may output a transmit power and an MCS rate.

[0052] While the disclosed power-management techniques have been illustrated with IEEE 802.11 -compatible communication by an access point, in other embodiments the disclosed power-management techniques may be used with a wide variety of communication protocols. For example, in some embodiments, the disclosed powermanagement techniques may be used by a base station in a cell in a cellular-telephone network.

[0053] In dense networks it may be beneficial to lower a transmit power of an access point. Lower transmit power allows access points to interfere less with neighbors operating on the same channel. Furthermore, clients typically use the power of beacon packets and possibly basic-rate management packets to discern when they should begin looking for another access point with better coverage. In a dense network, a high beacon power usually exacerbates the sticky client problem in which a client thinks that they have plenty of coverage because signal strength is high even though another alternative access point may be closer and may even offer better service.

[0054] Unfortunately, lowering the transmit power of the highest MCS rates decreases the coverage area of these MCS rates. Decreased coverage area for high MCS rates means that transmitting a packet to a client that may have taken a short period of time at a high MCS rate will now take a longer period of time at a lower MCS rate. This typically adds to air-time congestion rather than reducing airtime congestion.

[0055] Current power transmission profiles on the access point will typically set the maximum transmit power as a cap or upper bound. At best, all MCS rates may be transmitted at the same power. However, typically at the maximum access-point transmit power, the high MCS rates will be transmitted at a lower power level because of power-amplifier EVM requirements. As the transmit power cap is reduced, eventually all modulation classes or MCS rates are transmitted at the same transmit power. However, low MCS rates will always have longer range than higher MCS rates at the same transmit power because they are more-heavily coded.

[0056] A better solution in dense networks is to transmit high MCS rates at transmit-power levels higher than the transmit power level of beacons and managementtraffic. Using these power-management techniques, clients towards the center of the cell of an access point may still be served as well as if the access point was transmitting at maximum transmit power, but the range of the management frames may be greatly reduced because their transmit power is even lower than that of the high MCS packets.

[0057] In this scenario the network may get the best of all worlds. It gets high- traffic rates when connected to nearby access points, management traffic (which typically results in a significant part of network interference) may be transmitted at lower transmit powers, and the client may be encouraged to roam aggressively in a dense network to always be served by nearby access points.

[0058] The challenge to these power-management techniques is to make sure that the MCS rate versus range curve is always monotonic. This is because the management and beacon packets may need to have a longer range than high MCS packets even when they are transmitted at lower transmit power. Additionally, any packet with a lower- rate MCS than another packet may operate at a lower receive SNR. The implementation may need to be thought through carefully in order to ensure that the transmit rate control does not contain any assumptions about the transmit or receive characteristic of certain MCS rates are from other MCS rates (such as how many dB of extra path loss different they are). Consequently, the rate control may need to be changed to work with the different MCS versus path-loss profile.

[0059] In some embodiments, in the power-management techniques management packets that are transmitted with a lower transmit power may include: an association request, an association response, a re-association request, a re-association response, a probe response, and an authentication response. In addition, beacons may be transmitted with a lower transmit power. However, disassociation and deauthentication packet may not be transmitted with a lower transmit power.

[0060] Moreover, in some embodiments, the power-management techniques may be used to adjust the transmit power of management packets and / or data packets. For example, the transmit power of data packets having a high MCS rate may be transmitted at a higher transmit power and data packets having a low MCS rate may be transmitted at a lower transmit power.

[0061] One challenge in the power-management techniques is how to select the transmit powers. In some embodiments, a scan application on a cellular telephone (such as an iPhone from Apple, Inc. of Cupertino, California) may be used to perform a scan. Notably, a user may carry a cellular telephone to different locations (such as interstitiallocations between access points) and may use the scan application to collect scan data (such as RS SI over 60 s). (More generally, scans may be performed using a survey tool, such as a survey tool from Ekahau, Inc. of Seattle, Washington, or a survey tool from Hamina Wireless of Helsinki, Finland.) The scan data may include measured selective service set identifiers (SSIDSs) of access points and cumulative distribution functions (CDFs) for the access points as a function of scanned power (such as -83 to - 88 dBm) may be aggregated. The access points may be ranked based at least in part on their associated RS Sis at a 50% level in the CDFs.

[0062] In some embodiments, the cellular telephone (which is sometimes referred to as a client or a station) may perform a scan when the RSSI of a current associated access point is at or less than -70 dBm. Note that the client or the station may transition to a different access point (such as an access point having an RSSI of greater than -70 dBm) with 12 dBm of hysteresis (where the hysteresis may be the difference between primary coverage by the associated access point and the weakest viable access point).

[0063] When the worst RSSI power is less than -70 dBm and the hysteresis is greater than 12 dBm, the client or station may perform a BSS transition (otherwise, the client or station may be stuck, i.e., may not perform a BSS transition). For example, as shown in Table I, even though access point 5 with BSSID 8 has a 35 dBm larger RSSI than access point 5 with BSSID 9, the client or station still may not perform a BSS transition.Table 1

[0064] In the power-management techniques, one or more of the access points in a network may reduce the transmit power of a management packet (such as a beacon) and may trick the client or station into performing a scan and then performing a BSS transition. For example, in the power-management techniques, one or more of the access points may reduce their transmit powers by 9 dB from -66 dBm to -75 dBm (21 dBm to 12 dBm). In some embodiments, the transmit-power reduction may be applied to all access points evenly. In other embodiments, the transmit-power reduction may vary across at least some of the access points (such as by reducing the transmit power of one access point by 10 dBm) Note that the impact on the loading of the access points may be a constraint in the power-management techniques on the transmit-power adjustments.

[0065] For example, as shown in Table 2, with a management-packet transmit power level of 21 dBm, the client or station may not perform a BSS transition because it could be connected to an access point other than the primary one that has an RSSI greater than -70 dBm.Table 2

[0066] In some embodiments, when the management-packet transmit power of an access point is 21 dBm and the network is equally dense (in terms of the number of access points per unit area), the worst primary access-point coverage may be set to -75 dBm, which may result in more aggressive scanning.

[0067] Moreover, as shown in Table 3, by reducing the management-packet transmit power of all access points by 9 dBm (from 21 dBm to 12 dBm), the primary access point RS SI for the access point with the worst coverage may be reduced from - 66 dBm to -75 dBm. This may ensure that a client or a station may perform a scan and a BSS transition.Table 3

[0068] Furthermore, when all the access points have a management-packet transmit power of 12 dBm, there may still be one problematic access point. This access point may detect AP7 with a primary RSSI of -56 dBm and may detect AP3 with a worst RSSI of -69 dBm (and a hysteresis of 13 dB). However, by decreasing the management-packet transmit power of AP3 by an additional 1 dB may ensure that a client or station of this access point may perform a BSS transition.

[0069] In the power-management techniques, note that the setting of the transmit powers of the access points may be performed in a centralized or a distributed manner.

[0070] We now describe embodiments of an electronic device, which may perform at least some of the operations in the power-management techniques. FIG. 6 presents a block diagram illustrating an example of an electronic device 600 in accordance with some embodiments, such as one of: base station 108, one of electronic devices 110, computer 112, one of access points 116, one of radio nodes 118, switch 128 or authentication computer 130. This electronic device includes processing subsystem 610, memory subsystem 612, and networking subsystem 614. Processing subsystem 610 includes one or more devices configured to perform computational operations. For example, processing subsystem 610 can include one or more microprocessors, graphicsprocessing units (GPUs), ASICs, microcontrollers, programmable-logic devices, and / or one or more digital signal processors (DSPs).

[0071] Memory subsystem 612 includes one or more devices for storing data and / or instructions for processing subsystem 610 and networking subsystem 614. For example, memory subsystem 612 can include DRAM, static random access memory (SRAM), and / or other types of memory. In some embodiments, instructions for processing subsystem 610 in memory subsystem 612 include: one or more program modules or sets of instructions (such as program instructions 622 or operating system 624, such as Linux, UNIX, Windows Server, or another customized and proprietary operating system), which may be executed by processing subsystem 610. Note that the one or more computer programs, program modules or instructions may constitute a computer-program mechanism. Moreover, instructions in the various modules in memory subsystem 612 may be implemented in: a high-level procedural language, an object-oriented programming language, and / or in an assembly or machine language. Furthermore, the programming language may be compiled or interpreted, e.g., configurable or configured (which may be used interchangeably in this discussion), to be executed by processing subsystem 610.

[0072] In addition, memory subsystem 612 can include mechanisms for controlling access to the memory. In some embodiments, memory subsystem 612 includes a memory hierarchy that comprises one or more caches coupled to a memory in electronic device 600. In some of these embodiments, one or more of the caches is located in processing subsystem 610.

[0073] In some embodiments, memory subsystem 612 is coupled to one or more high-capacity mass-storage devices (not shown). For example, memory subsystem 612 can be coupled to a magnetic or optical drive, a solid-state drive, or another type of mass-storage device. In these embodiments, memory subsystem 612 can be used by electronic device 600 as fast-access storage for often-used data, while the mass-storage device is used to store less frequently used data.

[0074] Networking subsystem 614 includes one or more devices configured to couple to and communicate on a wired and / or wireless network (i.e., to perform network operations), including: control logic 616, an interface circuit 618 and one or more antennas 620 (or antenna elements). (While FIG. 6 includes one or more antennas 620, in some embodiments electronic device 600 includes one or more nodes, such as antenna nodes 608, e.g., a metal pad or a connector, which can be coupled to the one ormore antennas 620, or nodes 606, which can be coupled to a wired or optical connection or link. Thus, electronic device 600 may or may not include the one or more antennas 620. Note that the one or more nodes 606 and / or antenna nodes 608 may constitute input(s) to and / or output(s) from electronic device 600.) For example, networking subsystem 614 can include a Bluetooth™ networking system, a cellular networking system (e g., a 3G / 4G / 5G network such as UMTS, LTE, etc ), a universal serial bus (USB) networking system, a coaxial interface, a High-Definition Multimedia Interface (HDMI) interface, a networking system based on the standards described in IEEE 802.11 (e g., a Wi-Fi® networking system), an Ethernet networking system, and / or another networking system.

[0075] Note that a transmit or receive antenna pattern (or antenna radiation pattern) of electronic device 600 may be adapted or changed using pattern shapers (such as directors or reflectors) and / or one or more antennas 620 (or antenna elements), which can be independently and selectively electrically coupled to ground to steer the transmit antenna pattern in different directions. Thus, if one or more antennas 620 include N antenna pattern shapers, the one or more antennas may have 2Ndifferent antenna pattern configurations. More generally, a given antenna pattern may include amplitudes and / or phases of signals that specify a direction of the main or primary lobe of the given antenna pattern, as well as so-called ‘exclusion regions’ or ‘exclusion zones’ (which are sometimes referred to as ‘notches’ or ‘nulls’). Note that an exclusion zone of the given antenna pattern includes a low-intensity region of the given antenna pattern. While the intensity is not necessarily zero in the exclusion zone, it may be below a threshold, such as 3dB or lower than the peak gain of the given antenna pattern. Thus, the given antenna pattern may include a local maximum (e.g., a primary beam) that directs gain in the direction of electronic device 600 that is of interest, and one or more local minima that reduce gain in the direction of other electronic devices that are not of interest. In this way, the given antenna pattern may be selected so that communication that is undesirable (such as with the other electronic devices) is avoided to reduce or eliminate adverse effects, such as interference or crosstalk.

[0076] Networking subsystem 614 includes processors, controllers, radios / antennas, sockets / plugs, and / or other devices used for coupling to, communicating on, and handling data and events for each supported networking system. Note that mechanisms used for coupling to, communicating on, and handling data and events on the network for each network system are sometimes collectivelyreferred to as a ‘network interface’ for the network system. Moreover, in some embodiments a ‘network’ or a ‘connection’ between the electronic devices does not yet exist. Therefore, electronic device 600 may use the mechanisms in networking subsystem 614 for performing simple wireless communication between the electronic devices, e.g., transmitting advertising or beacon frames and / or scanning for advertising frames transmitted by other electronic devices as described previously.

[0077] Within electronic device 600, processing subsystem 610, memory subsystem 612, and networking subsystem 614 are coupled together using bus 628. Bus 628 may include an electrical, optical, and / or electro-optical connection that the subsystems can use to communicate commands and data among one another. Although only one bus 628 is shown for clarity, different embodiments can include a different number or configuration of electrical, optical, and / or electro-optical connections among the subsystems.

[0078] In some embodiments, electronic device 600 includes a display subsystem 626 for displaying information on a display, which may include a display driver and the display, such as a liquid-crystal display, a multi-touch touchscreen, etc.

[0079] Moreover, electronic device 600 may include a user-interface subsystem 630, such as: a mouse, a keyboard, a trackpad, a stylus, a voice-recognition interface, and / or another human-machine interface. In some embodiments, user-interface subsystem 630 may include or may interact with a touch-sensitive display in display subsystem 626.

[0080] Electronic device 600 can be (or can be included in) any electronic device with at least one network interface. For example, electronic device 600 can be (or can be included in): a desktop computer, a laptop computer, a subnotebook / netbook, a server, a tablet computer, a cloud-based computing system, a smartphone, a cellular telephone, a smartwatch, a wearable electronic device, a consumer-electronic device, a portable computing device, an access point, a transceiver, a router, a switch, communication equipment, an eNodeB, a controller, test equipment, and / or another electronic device.

[0081] Although specific components are used to describe electronic device 600, in alternative embodiments, different components and / or subsystems may be present in electronic device 600. For example, electronic device 600 may include one or more additional processing subsystems, memory subsystems, networking subsystems, and / or display subsystems. Additionally, one or more of the subsystems may not be presentin electronic device 600. Moreover, in some embodiments, electronic device 600 may include one or more additional subsystems that are not shown in FIG. 6. Also, although separate subsystems are shown in FIG. 6, in some embodiments some or all of a given subsystem or component can be integrated into one or more of the other subsystems or component s) in electronic device 600. For example, in some embodiments instructions 622 is included in operating system 624 and / or control logic 616 is included in interface circuit 618.

[0082] Moreover, the circuits and components in electronic device 600 may be implemented using any combination of analog and / or digital circuitry, including: bipolar, PMOS and / or NMOS gates or transistors. Furthermore, signals in these embodiments may include digital signals that have approximately discrete values and / or analog signals that have continuous values. Additionally, components and circuits may be single-ended or differential, and power supplies may be unipolar or bipolar.

[0083] An integrated circuit (which is sometimes referred to as a ‘communication circuit’) may implement some or all of the functionality of networking subsystem 614 and / or of electronic device 600. The integrated circuit may include hardware and / or software mechanisms that are used for transmitting wireless signals from electronic device 600 and receiving signals at electronic device 600 from other electronic devices. Aside from the mechanisms herein described, radios are generally known in the art and hence are not described in detail. In general, networking subsystem 614 and / or the integrated circuit can include any number of radios. Note that the radios in multipleradio embodiments function in a similar way to the described single-radio embodiments.

[0084] In some embodiments, networking subsystem 614 and / or the integrated circuit include a configuration mechanism (such as one or more hardware and / or software mechanisms) that configures the radio(s) to transmit and / or receive on a given communication channel (e.g., a given carrier frequency). For example, in some embodiments, the configuration mechanism can be used to switch the radio from monitoring and / or transmitting on a given communication channel to monitoring and / or transmitting on a different communication channel. (Note that ‘monitoring’ as used herein comprises receiving signals from other electronic devices and possibly performing one or more processing operations on the received signals).

[0085] In some embodiments, an output of a process for designing the integrated circuit, or a portion of the integrated circuit, which includes one or more of the circuits described herein may be a computer-readable medium such as, for example, a magnetic tape or an optical or magnetic disk. The computer-readable medium may be encoded with data structures or other information describing circuitry that may be physically instantiated as the integrated circuit or the portion of the integrated circuit. Although various formats may be used for such encoding, these data structures are commonly written in: Caltech Intermediate Format (CIF), Calma GDS II Stream Format (GDSII) or Electronic Design Interchange Format (EDIF), OpenAccess (OA), or Open Artwork System Interchange Standard (OASIS). Those of skill in the art of integrated circuit design can develop such data structures from schematics of the type detailed above and the corresponding descriptions and encode the data structures on the computer-readable medium. Those of skill in the art of integrated circuit fabrication can use such encoded data to fabricate integrated circuits that include one or more of the circuits described herein.

[0086] While the preceding discussion used Wi-Fi, LTE and / or Ethernet communication protocols as illustrative examples, in other embodiments a wide variety of communication protocols and, more generally, communication techniques may be used. Thus, the power-management techniques may be used in a variety of network interfaces. Furthermore, while some of the operations in the preceding embodiments were implemented in hardware or software, in general the operations in the preceding embodiments can be implemented in a wide variety of configurations and architectures. Therefore, some or all of the operations in the preceding embodiments may be performed in hardware, in software or both. For example, at least some of the operations in the power-management techniques may be implemented using program instructions 622, operating system 624 (such as a driver for interface circuit 618) or in firmware in interface circuit 618. Alternatively or additionally, at least some of the operations in the power-management techniques may be implemented in a physical layer, such as hardware in interface circuit 618.

[0087] Note that the use of the phrases ‘capable of,’ ‘capable to,’ ‘operable to,’ or ‘configured to’ in one or more embodiments, refers to some apparatus, logic, hardware, and / or element designed in such a way to enable use of the apparatus, logic, hardware, and / or element in a specified manner.

[0088] While examples of numerical values are provided in the preceding discussion, in other embodiments different numerical values are used. Consequently, the numerical values provided are not intended to be limiting.

[0089] In the preceding description, we refer to ‘some embodiments.’ Note that ‘some embodiments’ describes a subset of all of the possible embodiments, but does not always specify the same subset of embodiments.

[0090] The foregoing description is intended to enable any person skilled in the art to make and use the disclosure, and is provided in the context of a particular application and its requirements. Moreover, the foregoing descriptions of embodiments of the present disclosure have been presented for purposes of illustration and description only.They are not intended to be exhaustive or to limit the present disclosure to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. Additionally, the discussion of the preceding embodiments is not intended to limit the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

CLAIMSWhat is claimed is:

1. An electronic device, comprising: an interface circuit, wherein the interface circuit is configured to: dynamically adjust transmit power of a packet based at least in part on a type of the packet; and dynamically adjust the transmit power of the packet based at least in part on a modulation coding scheme (MCS) rate of the packet, wherein a given packet having a lower MCS rate has a lower transmit power.

2. The electronic device of claim 1, wherein the electronic device comprises an access point.

3. The electronic device of claim 1 , wherein a management packet or a data packet has a lower transmit power than a second data packet having an MCS rate greater than a predefined threshold.

4. The electronic device of claim 1, wherein a management packet and a data packet have different transmit powers.

5. The electronic device of claim 4, wherein the management packet comprises a beacon.

6. The electronic device of claim 4, wherein the management packet comprises: an association request, an association response, a re-association request, a reassociation response, a probe response, and an authentication response.

7. The electronic device of claim 1, wherein a disassociation request and an authentication packet have a different transmit power than other management packets.

8. The electronic device of claim 1, wherein the packet having an MCS greater than a predefined threshold has a higher transmit power.

9. The electronic device of claim 8, wherein the predefined threshold comprises MCS 5, MCS 8 or MCS 11.

10. The electronic device of claim 1, wherein the predefined threshold corresponds to a density of network that includes the electronic device.

11. A non-transitory computer-readable storage medium for use in conjunction with an electronic device, the computer-readable storage medium storing program instructions that, when executed by the electronic device, cause the electronic device to perform operations comprising: dynamically adjust transmit power of a packet based at least in part on a type of the packet, and dynamically adjust the transmit power of the packet based at least in part on a modulation coding scheme (MCS) rate of the packet, wherein a given packet having a lower MCS rate has a lower transmit power.

12. The non-transitory computer-readable storage medium of claim 11, wherein the electronic device comprises an access point.

13. The non-transitory computer-readable storage medium of claim 11, wherein a management packet and a data packet have different transmit powers.

14. The non-transitory computer-readable storage medium of claim 11, wherein the packet having an MCS greater than a predefined threshold has a higher transmit power.

15. The non-transitory computer-readable storage medium of claim 14, wherein the predefined threshold comprises MCS 5, MCS 8 or MCS 11.

16. A method for adjusting a transmit power, comprising: by an electronic device: dynamically adjust the transmit power of a packet based at least in part on a type of the packet; and dynamically adjust the transmit power of the packet based at least in part on a modulation coding scheme (MCS) rate of the packet, wherein a given packet having a lower MCS rate has a lower transmit power.

17. The method of claim 16, wherein the electronic device comprises an access point.

18. The method of claim 16, wherein a management packet and a data packet have different transmit powers.

19. The method of claim 16, wherein the packet having an MCS greater than a predefined threshold has a higher transmit power.

20. The method of claim 19, wherein the predefined threshold comprises MCS 5, MCS8orMCS 11.

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