Multi-radio wireless transceiver power savings

Abstract

The invention relates to multi-radio wireless transceiver power saving. A wireless transceiver has components coupled to each other to form a transmit chain and a receive chain for a plurality of radios that support wireless communication with associated sites on a corresponding wireless local area network (WLAN). The wireless transceiver also includes associating, with the monitoring circuitry, the target circuitry and the power back-off circuitry. The utilization monitoring circuitry monitors communications between each of the radios and its associated site. And an association target circuit that identifies an underutilized one of the radios as a target radio for re-associating a site currently associated with the at least one other radio based on the monitored communication with the monitoring circuit, and initiating the re-association of the target radio with the station currently associated with the at least one other radio. The power back-off circuitry responds to the associated target circuitry to reduce power of the at least one other radio.

Description

[0001] Information about divisional applications

[0002] This application is a divisional application. The parent application is an invention patent application with application date of May 30, 2019, application number 201980036176.3, and invention name “Power Saving of Multi-Radio Wireless Transceiver”.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims the benefit of and priority to previously filed co-pending U.S. non-provisional application No. 15 / 995,089, filed on May 31, 2018, entitled “MULTI-RADIO WIRELESS TRANSCEIVER POWER CONSERVATION,” and claims the benefit of and priority to International Application No. PCT / US19 / 34742, filed on May 30, 2019. Technical Field

[0005] The field of the present invention relates generally to wireless local area networks including wireless access points (WAPs) and wireless stations, and particularly to enhanced multi-radio wireless transceivers for use therein. Background Art

[0006] Home and office networks, also known as wireless local area networks (WLANs), are established using devices called wireless access points (WAPs). WAPs may include routers. WAPs wirelessly couple all wireless stations on a WLAN to each other and to the Internet via wired or digital subscriber lines. Wireless stations include: computers, tablets, mobile phones, printers, televisions, digital video (DVD) players, and Internet of Things (IoT) clients, such as smoke detectors, door locks, etc. Most WAPs implement the IEEE 802.11 standard, which is a competition-based standard for handling communications between multiple competing stations sharing a wireless communication medium on a selected communication channel among multiple communication channels. The frequency range of each communication channel is specified in the corresponding protocol of the implemented IEEE 802.11 protocol, such as "a", "b", "g", "n", "ac", "ad", "ax". Communications follow a hub and spoke model, with a WAP at the hub and a spoke corresponding to a wireless link to each "client" device (also known as a station).

[0007] After selecting a communication channel for the associated home network, access to the shared communication channel relies on a multiple access method identified as Conflict Listening Multiple Access (CSMA). Communications on a single communication medium are identified as "simplex," meaning one communication stream at a time from a single source node to one or more destination nodes, with all remaining nodes able to "listen" to the subject transmission. CSMA provides a distributed random access method for sharing a single communication medium. Stations contend for a communication link to the WAP, and in doing so avoid colliding with each other by initiating a link only when monitored energy levels indicate that the medium is available.

[0008] With the adoption of Multiple Input Multiple Output (MIMO) communications in the IEEE 802.11n standard, the communication throughput capacity on the 2.4 GHz or 5 GHz communication bands has been greatly enhanced with the introduction of 4×4 MIMO communications. MIMO uses multiple transmit and receive antennas (also known as MIMO antenna arrays) on a WAP and multipath propagation between stations at either end of the communication link to multiply the capacity of a wireless communication link.

[0009] Starting with the IEEE 802.11ac standard and specifically with “Wave 2” of the standard, the so-called multi-user (MU) MIMO capability of the WAP (where up to 8 antennas support 8 communication streams, also known as 8×8 MIMO) can be used to conduct discrete communications with more than one target node simultaneously. MU capability was added to the standard to enable a WAP to transmit downlink communications to multiple stations simultaneously, thereby increasing the available time for discrete MIMO video links to wireless HDTVs, computer tablets, and other high-throughput wireless devices. The IEEE 802.11ad standard encodes support for communications on the 60 GHz band. The IEEE 802.11ax standard extends MU MIMO capability to include concurrent uplinks from two or more stations to the WAP.

[0010] Recently, multi-radio transceivers have been introduced that incorporate multiple radios in a single WAP, each radio supporting a wireless local area network (WLAN) on a corresponding channel of one or more wireless communication bands (e.g., 2.4 GHz, 5 GHz, or 60 GHz bands). Each communication band has its own wireless protocol, channel width, and number of channels.

[0011] What is needed is a method for improving the performance of these multi-radio transceivers. Summary of the invention

[0012] The present invention provides a method and apparatus for a wireless transceiver having multiple components coupled to each other to form a transmit chain and a receive chain of multiple radios, each of the multiple radios supporting wireless communications with associated stations on a corresponding wireless local area network (WLAN). The wireless transceiver also includes: a utilization monitoring circuit, an association target circuit, and a power backoff circuit. The utilization monitoring circuit monitors communications between each of the multiple radios and its associated stations. The association target circuit identifies an underutilized radio among the radios as a target radio for reassociating a station currently associated with at least one other radio among the multiple radios based on the monitored communications of the utilization monitoring circuit, and initiates the reassociation of the target radio with the station currently associated with the at least one other radio. The power backoff circuit responds to the association target circuit to reduce the power of at least one other radio among the multiple radios.

[0013] The present invention can be implemented in hardware, firmware, or software.

[0014] Associated methods and circuits are also claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] These and other features and advantages of the present invention will become more apparent to those skilled in the art through the following detailed description in conjunction with the accompanying drawings, in which:

[0016] Figures 1A to 1C are respectively a system diagram, a band plan, and a site capability table of a representative multi-radio wireless transceiver with a power saving circuit according to an embodiment of the present invention;

[0017] FIG. 2A to FIG. 2B , Figure 2C to Figure 2D is a system view and band planning diagram of a multi-radio wireless transceiver before and after merging communications onto a single communications band under the control of a power saving circuit;

[0018] Figure 3 is a detailed circuit diagram of a multi-radio wireless transceiver having multiple radios, each radio supporting communications with an associated station on a corresponding one of three communications bands and operating under control of a power saving circuit, according to an embodiment of the present invention; and

[0019] Figure 4 is a process flow diagram of a process associated with conserving power on a multi-radio wireless transceiver. DETAILED DESCRIPTION

[0020] Figures 1A to 1C 2 are a system diagram of a representative multi-radio transceiver with power saving circuitry, a frequency band plan, and a site capability table, respectively, according to an embodiment of the present invention.

[0021] Figure 1A 1 is a system view of a multi-radio wireless transceiver 102 in a home 100. In this embodiment of the invention, the multi-radio transceiver operates as a wireless access point (WAP) that includes three transceivers, also referred to as radios: 106, 110, and 114. Each radio supports wireless communications with associated stations of stations 130-142 on corresponding wireless local area networks of three wireless local area networks (WLANs) 120-124. In this embodiment of the invention, the IEEE 802.11n-compliant radio 106 operates in the 2.4 GHz band and has the widest coverage (210 feet) and the lowest throughput (600 Mbps) of the three radios. The radio 106 provides the WLAN 120 to associated stations, such as stations 130-136. The IEEE 802.11ac-compliant radio 110 has a coverage of 90 feet and a throughput of 3.2 Gbps in the 5 GHz band. Radio 110 provides WLAN 122 to associated stations, such as stations 138-140. Radio 114 complies with the IEEE 802.11ad standard and operates in the 60 GHz band, with the narrowest coverage of 15 feet and the highest throughput of 7 Gbps among the three radios. Radio 114 provides WLAN 124 to associated stations, such as station 140. Each radio may include support for multiple-input multiple-output (MIMO) communications. In the illustrated embodiment, all three radios support MIMO wireless communications. Radio 106 has two external antennas 108; radio 110 has four external antennas 112, and radio 114 has two patch antennas 116. Each radio operates under the control of a power saving circuit 118 integrated with a WAP. In an alternative embodiment of the present invention, two or more radios may include support for communications in the same frequency band (e.g., the 2.4 GHz band) and provide different WLANs to their associated stations in that frequency band.

[0022] The power saving circuit 118 determines which radios (if any) can be subjected to power reduction during intervals of low demand to reduce the overall power consumption of the WAP. The power saving circuit includes the following circuits: utilization monitoring circuit 118A, association target circuit 118B, power backoff circuit 118D and radio controller circuit 118E. The utilization monitoring circuit 118A monitors the business and / or airtime utilization on each WLAN in the WLAN. The association target circuit 118B uses input from the utilization monitoring subcircuit to identify any underutilized radio as a target radio for reassociating a station currently associated with another radio in the radio. Then, the association target circuit initiates reassociation, in some cases subject to one or more prerequisites. One such prerequisite is that the reassociated station has the ability to support communication with the target radio (specifically, the communication band in which the radio operates, for example, 2.4 GHz, 5 GHz or 60 GHz). Each radio determines the station capabilities during the capability exchange before association. The association target circuit is coupled to each radio and obtains these capabilities from each radio. Figure 1C Table 150 shows the capabilities of each radio obtained by the association target circuit. The association target circuit stores these capabilities in the capability record 140B in the non-volatile storage device 104. In an embodiment of the present invention, a match between the capabilities of the station subject to reassociation and the capabilities of the target radio is a prerequisite for reassociation. The association target circuit conditionally initiates reassociation with the target radio based on determining that the station currently associated with at least one other radio includes capabilities for supporting communications on the target radio.

[0023] In another embodiment of the present invention, a prerequisite for reassociation is the utilization level of the target radio and other radios selected for site disassociation. In an embodiment of the present invention, the association target circuit conditionally initiates reassociation with the target radio based on a prediction that the target radio's resulting utilization metric after reassociation will not exceed a maximum utilization level. In another embodiment of the present invention, the association target circuit conditionally initiates reassociation with the target radio based on a prediction that the target radio's resulting aggregate talk time metric after reassociation will not exceed a maximum talk time level. In another embodiment of the present invention, the association target circuit conditionally initiates reassociation with the target radio based on a prediction that the target radio's resulting aggregate traffic metric after reassociation will not exceed a maximum traffic level. The current utilization (e.g., talk time % or traffic) of the target radio must be low enough to take on additional traffic / talk time without causing congestion. Utilization can be defined as traffic volume, e.g., Mbps, or as a percentage of talk time. Quantification of the impact of reassociation on the utilization of the target radio can be determined with varying degrees of precision. Reassociation may be feasible in the case where the current utilization of the radio to which the site is to be reassociated is low enough. In another embodiment of the present invention, the reassociation target subcircuit 118B includes a utilization prediction subcircuit 118C. The subcircuit stores a record 104A of the traffic, airtime, and throughput requirements of each station on any communication bands that have been previously associated with the station in the non-volatile storage device 104. The utilization prediction subcircuit uses these records to accurately predict the aggregate traffic or airtime utilization requirements resulting from the expected reassociation, thereby avoiding radio reassociations that will result in congested communications on the target band. Reassociation can be triggered proactively or reactively. In an embodiment of the present invention, a transition management marker (e.g., a band change notification) is transmitted by the radios whose stations are to be reassociated to those stations, thereby identifying the target radio as the radio for reassociation. In another embodiment of the present invention, the power backoff circuit initiates reassociation by reducing the power of the radios whose stations are to be reassociated.

[0024] In another embodiment of the present invention, the association target circuit identifies an underutilized radio among the radios when the utilization metric of the target radio exceeds a maximum utilization level, and reassociates sufficient sites from the target radio to the identified underutilized radio among the radios to reduce the level of the utilization metric for the target radio to below the maximum utilization level.

[0025] The power backoff subcircuit 118D, via its connection to the radio controller subcircuit 118E, enables the reduction or shutoff of power to the radio whose station is subject to reassociation. In various embodiments of the invention, the power reduction may take one or more of the following forms: shutting off the power on the radio whose station is being reassociated, terminating communications on the subject radio, or reducing the number of antennas and associated transmit and receive chains on those radios. These power reductions may be pre-reassociation conditions, in which case the station responding to the power reduction initiates reassociation with the target radio itself. Alternatively, the power reduction may be a post-reassociation condition, in which case the power is reduced after the station has reassociated with the target radio.

[0026] Figure 1B A representative set of IEEE 802.11 band plans 160-164 are shown, one or more of which may be supported by a corresponding radio in the radio of the WAP. Radio 106 operates WLAN 120 in the 2.4 GHz band 160 on one or more of 14 channels associated therewith. Channels are referred to as orthogonal frequency division multiplexing (OFDM), where each channel includes multiple OFDM subchannels or tones. Radio 110 operates WLAN 122 in the 5 GHz band 162 on one or more of 25 OFDM channels associated therewith. Radio 116 operates WLAN 124 in the 60 GHz band 164 on one or more of 3 OFDM channels associated therewith. In another embodiment of the present invention, radios 106 and 110 each operate on different channels in the 2.4 GHz band.

[0027] Figure 1C A site capabilities table 150 is shown showing support for one or more of the communication bands supported by the WAP of each of the sites in home 100. All sites support communication on the 2.4 GHz band. Site 142 supports communication on any of the three bands supported by the WAP. Sites 136-140 support communication on either the 2.4 GHz or 5 GHz bands. Sites 130-134 support communication on only the 2.4 GHz band.

[0028] FIG. 2A to FIG. 2B , Figure 2C to Figure 2D 1. A system view and band plan diagram of a multi-radio transceiver before and after reassociating stations from corresponding radios of the three radios 106, 110, 114 to the single radio 106 under the control of the power save circuit 118.

[0029] Figure 2A1 is a system view of a multi-radio transceiver 102 in a home 100 serving each of the stations 132-142 on a corresponding one of the WLANs 120-124 provided by a corresponding one of the radios 106, 110, and 114. Due to the power consumption of the three active radios 106, 110, and 114, the total power consumption of the WAP 102 is at a maximum.

[0030] Figure 2B It is shown that Figure 2A Band planning diagram of talk time relative to power for each communication band and corresponding WLAN provided by corresponding active radios in the three active radios shown. Radios 106, 110 and 114 are shown as consuming 3 watts, 1.25 watts and 1.5 watts respectively. Power consumption will further vary based on the business. In the example shown, each radio is not fully utilized, as reflected in the talk time required to serve the corresponding associated site. Radio 106 providing WLAN 120 on 2.4 GHz band 160 to sites 130-136 has a talk time utilization of 25% of the theoretical maximum capacity of the WLAN. Radio 110 providing WLAN 122 on 5 GHz band 162 to sites 138-140 has a talk time utilization of 10% of the theoretical maximum capacity of the WLAN. Radio 116 providing WLAN 124 on 60 GHz band 164 to site 142 has a talk time utilization of 10% of the theoretical maximum capacity of the WLAN.

[0031] Figure 2C 1 is a system view of the multi-radio transceiver 102 in the home 100 after reassociating the stations 138-142 from the radios 110 and 114 to the single WLAN 120 provided by the radio 106. Since the power saving circuit 118 shuts down the power to two of the three radios (i.e., the radios 110 and 114), the overall power consumption of the WAP 102 is at a minimum.

[0032] Figure 2D Shown in Figure 2C Bandplan of talk time versus power for each communication band after consolidation is shown. Radios 106, 110, and 114 are shown as consuming 5 watts, 0 watts, and 0 watts, respectively. Power consumption will further vary based on traffic. In the example shown, power conservation circuitry 118 has detected that Figure 2BAll three frequency bands 160-164 are shown to be underutilized, and therefore the stations 138-142 have been reassociated to a single target radio 106 operating in the 2.4 GHz band, and the power of the radios 110, 114 has been reduced or turned off accordingly. The radio 106 providing the WLAN 120 on the 2.4 GHz band 160 to the stations 130-142 has an airtime utilization of 98% of the theoretical maximum capacity of the WLAN. The radio 110 has been turned off, and therefore the WLAN 122 on the 5 GHz band is no longer provided. In another embodiment of the present invention, the power reduction on the radio 110 may be less severe, for example, maintaining power on 1 of the 4 communication chains serving each antenna and turning off power on the remaining 3 chains. The radio 114 has been turned off, and therefore the WLAN 124 on the 60 GHz band is no longer provided. In another embodiment of the present invention, the power reduction on the radio 114 may be less severe, for example, maintaining WLAN beacons but not accepting station associations.

[0033] Figure 3 1 is a detailed circuit diagram of a multi-radio transceiver 120 operating as a WAP according to an embodiment of the present invention, having multiple radios, each radio supporting communications with associated stations on corresponding ones of three communication bands and access to the Internet, and operating under the control of power saving circuits. In this embodiment of the present invention, the WAP 120 includes three radios 106, 110, and 114, wherein a representative radio of the MIMO radio 106 is shown in detail.

[0034] The radio 106 may be instantiated on one or more VLSI chips (e.g., chip 106A). The radio 106 is identified as a 2×2 multiple-input multiple-output (MIMO) WAP that supports up to 2 discrete communication streams through its MIMO antenna array 108. The radio is coupled to the Internet via an Ethernet media access control (EMAC) interface 312 through a wired, fiber, or digital subscriber line (DSL) backbone connection (not shown). The packet bus 310 couples the EMAC to the Wi-Fi stage, which includes multiple components for forming transmit and receive paths / chains for wireless uplink and downlink communications. The Wi-Fi stage of the radio 106 includes: a MIMO Wi-Fi baseband 316 stage and an analog front end (AFE) and radio frequency (RF) stage 318.

[0035] In the baseband section 316, wireless communications transmitted to or received from each associated user / client / station are processed. The baseband section can be dynamically configured to support single-user or multi-user communications with associated stations. The AFE and RF section 318 handles the up-conversion on each transmit path of the wireless transmission initiated in the baseband. The RF section also handles the down-conversion of the signals received on the receive path and passes them to the baseband for further processing.

[0036] Transmission: The transmit path / chain includes the following discrete and shared components. The Wi-Fi Medium Access Control (WMAC) component 320 includes: a hardware queue 322A for each downlink and uplink communication flow; encryption and decryption circuitry 322B for encrypting and decrypting downlink and uplink communication flows; medium access circuitry 322C for performing clear channel assessment (CCA) and making exponential random backoff and retransmission decisions; and packet processor circuitry 322D for packet processing of communication flows. The WMAC component has a node table 322E that lists each node / station on the WLAN, the station's capabilities, the corresponding encryption key, and the priority associated with its communication traffic.

[0037] Each sounding or data packet is framed in the framer 330 for wireless transmission to one or more stations on the transmit path component. Next, each stream is encoded and scrambled in the encoder and scrambler 332 before being demultiplexed into two streams in the demultiplexer 334. Each stream is then interleaved and mapped in a corresponding interleaver mapper in the interleaver mapper 336. Next, the downlink transmission is spatially mapped in the spatial mapper 338 using a beamforming matrix (also referred to as a precoding matrix 'Q' 340). The spatially mapped stream from the spatial mapper is input to an inverse discrete Fourier transform (IDFT) component 342 for conversion from the frequency domain to the time domain and subsequent transmission on a corresponding transmit chain in the transmit chain in the AFE and RF stage 318.

[0038] The IDFT on each transmit path / chain is coupled to a corresponding component in the transmit path / chain components in the AFE / RF stage 318. Specifically, each IDFT in the IDFT 342 is coupled to an associated digital-to-analog converter in a digital-to-analog converter (DAC) 344 for converting digital transmissions to analog transmissions. Next, each transmit chain is filtered in a filter 346 (e.g., a bandpass filter) to control the bandwidth of the transmission. After filtering, the transmission is up-converted in an up-converter 348 to the center frequency of a selected channel within the 2.4 GHz band supported by the radio 106. Each up-converter is coupled to a voltage controlled oscillator (VCO) 350 to up-convert the transmission to the appropriate center frequency of the selected channel. Next, one or more amplification stages are provided on each chain by a power amplifier 352. The power amplifier on each of the two transmit chains in the radio is coupled to a corresponding antenna in the two antennas 108 for transmitting downlink communications to an associated station.

[0039] Receive: The receive path / chain includes the following discrete and shared components. In the AFE-RF stage 318, the communications received on the MIMO antenna array 108 of the transceiver are RF processed, including down-conversion. The site uplink received on the antenna 108 is amplified in the corresponding low noise amplifier in the low noise amplifier 360. The down-converter 362 is coupled to the VCO 350 for down-converting the received signal on each chain. The received signal of each chain is then filtered in the filter 364. Next, the down-converted analog signal on each chain is digitized in the corresponding analog-to-digital converter in the analog-to-digital converter (ADC) 366. The digital output from each ADC is passed to the corresponding component in the discrete Fourier transform (DFT) component 368 in the baseband portion 316 of the Wi-Fi stage for conversion from the time domain to the frequency domain.

[0040] The receive processing in the baseband stage includes the following discrete and shared components. An equalizer 370 for mitigating channel impairments is coupled to the output of the DFT 368. The received stream at the output of the equalizer is subjected to demapping and deinterleaving in a corresponding one of a demapper 372 and a deinterleaver 374. Next, the received stream is multiplexed in a multiplexer 376 and decoded and descrambled in a decoder and descrambler component 378, and then deframed in a deframer 380. The received communication is then passed to the WMAC component 320, where the received communication is decrypted with a decryption circuit 322B and placed in an appropriate upstream hardware queue 322A for upload to the Internet.

[0041] The WAP also includes a radio control processor 300 for instantiating radio control functions 302 provided by program code 304A in non-volatile memory 304. The radio control functions instantiated on processor 300 include responses to requests and instructions from power saving circuitry 118.

[0042] The 5 GHz radio 110 may be instantiated on one or more VLSI chips (e.g., chip 110A). The radio 110 is identified as a 4×4 MIMO WAP that supports up to 4 discrete communication streams through its MIMO antenna array 112. The radio 110 instantiated on one or more chips 110A includes components similar to those discussed above in conjunction with the 2.4 GHz radio 106. The radio control processor of the radio 110 is also coupled to the power saving circuit 118 and responds to requests and instructions from the power saving circuit 118.

[0043] The 60 GHz radio 114 may be instantiated on one or more VLSI chips (e.g., chip 114A). The radio 114 is identified as a 2×2 MIMO WAP that supports up to 2 discrete communication streams through its MIMO patch antenna array 116. The radio 114 instantiated on one or more chips 114A also includes components similar to those discussed above in conjunction with the 2.4 GHz radio 106. The radio control processor of the radio 114 is also coupled to the power saving circuit 118 and responds to requests and instructions from the power saving circuit 118.

[0044] The power saving circuit 118 may also be implemented as a discrete chip 118A or part of a chip on a very large scale integrated circuit. The power saving circuit 118 determines which radios (if any) can be subjected to power reduction during intervals of low demand to reduce the overall power consumption of the WAP. The power saving circuit includes the following subcircuits: utilization monitoring 118A, association target 118B, power backoff 118D, and radio controller 118E. The utilization monitoring circuit 118A monitors the communication between the multi-radio wireless transceiver and the associated stations on the corresponding communication bands in the plurality of communication bands. The monitoring may include the overall traffic or talk time on the WLAN or on each link of the WLAN. The utilization monitoring circuit obtains the traffic or talk time information from the radio control circuit 302 and specifically from the WMAC circuit 320 to which it is connected. The traffic volume or talk time demand may be derived from either or both of the hardware queues 322A for uplink and downlink flows and the packet processor circuit 322D for packet processing of the communication flow of each radio.

[0045] The association target circuitry 118B utilizes input from the utilization monitoring subcircuit to identify any underutilized radios as target radios for reassociation with a site currently associated with another of the radios. The association target circuitry then initiates the reassociation, subject in some cases to one or more prerequisites. One such prerequisite is that the site being reassociated has the capability to support communications with the target radio, specifically the communications band in which the radio operates, e.g., 2.4 GHz, 5 GHz, or 60 GHz. Each radio determines site capabilities during a capability exchange prior to association. The association target circuitry couples to each radio and obtains these capabilities from each radio. Figure 1C Table 150 shows the capabilities of each radio obtained by the association target circuit. The association target circuit stores these capabilities in a capability record 140B in the non-volatile storage device 104. In an embodiment of the present invention, a match between the capabilities of the site subject to reassociation and the capabilities of the target radio is a prerequisite for reassociation. The association target circuit conditionally initiates reassociation with the target radio based on determining that the site currently associated with at least one other radio includes capabilities for supporting communications on the target radio. The association target circuit obtains this capability information via the radio control circuit 302 of each radio and specifically via the node table 322E of the WMAC circuit 320 of each radio to which it is coupled.

[0046] In another embodiment of the present invention, a prerequisite for reassociation is the utilization level of the target radio and other radios selected for site disassociation. In an embodiment of the present invention, the association target circuit conditionally initiates reassociation with the target radio based on a prediction that the target radio's resulting utilization metric after reassociation will not exceed a maximum utilization level. In another embodiment of the present invention, the association target circuit conditionally initiates reassociation with the target radio based on a prediction that the target radio's resulting aggregate talk time metric after reassociation will not exceed a maximum talk time level. In another embodiment of the present invention, the association target circuit conditionally initiates reassociation with the target radio based on a prediction that the target radio's resulting aggregate traffic metric after reassociation will not exceed a maximum traffic level. The current utilization (e.g., talk time % or traffic) of the target radio must be low enough to take on additional traffic / talk time without causing congestion. Utilization can be defined as traffic volume, e.g., Mbps, or as a percentage of talk time. Quantification of the impact of reassociation on the utilization of the target radio can be determined with varying degrees of precision. Reassociation may be feasible in the case where the current utilization of the radio to which the site is to be reassociated is low enough. In another embodiment of the present invention, the reassociation target subcircuit 118B includes a utilization prediction subcircuit 118C. The subcircuit stores a record 104A of the traffic, airtime, and throughput requirements of each station on any communication band that has been previously associated with the station in the non-volatile storage device 104. The utilization prediction subcircuit uses these records to accurately predict the aggregate traffic or airtime utilization requirements resulting from the expected reassociation, thereby avoiding radio reassociations that will result in congested communications on the target band. Reassociation can be triggered proactively or reactively. In an embodiment of the present invention, transition management markers (e.g., 802.11ac band transition notifications, 802.11ad fast session transfers) are transmitted by the radios to which the stations are to be reassociated, thereby identifying the band service by the target radio for reassociation. In another embodiment of the present invention, the power backoff circuit initiates reassociation by reducing the power of the radio to which the station is to be reassociated.

[0047] In another embodiment of the present invention, the association target circuit identifies an underutilized radio among the radios when the utilization metric of the target radio exceeds a maximum utilization level, and reassociates sufficient sites from the target radio to the identified underutilized radio among the radios to reduce the level of the utilization metric for the target radio to below the maximum utilization level.

[0048] The power backoff subcircuit 118D, via its connection to the radio controller subcircuit 118E, enables the reduction or shutoff of power to the radio whose station is subject to reassociation. In various embodiments of the invention, the power reduction may take one or more of the following forms: shutting off the power on the radio whose station is being reassociated, terminating communications on the subject radio, or reducing the number of antennas and associated transmit and receive chains on those radios. These power reductions may be pre-reassociation conditions, in which case the station responding to the power reduction initiates reassociation with the target radio itself. Alternatively, the power reduction may be a post-reassociation condition, in which case the power is reduced after the station has reassociated with the target radio.

[0049] Figure 4 4 is a process flow diagram of a process associated with saving power on a multi-radio transceiver 102. Processing begins with the interaction of the power saving circuit with each radio on the multi-radio transceiver. In decision process 400, each radio in the multi-radio transceiver is queried to determine the capabilities and identity of each associated station in process 402. In decision process 404, each radio is queried to provide the information required to monitor the overall and per-link traffic or airtime usage percentage of the associated stations on the communication band of the subject radio. Next, in process 406, the identity, capability traffic, and / or airtime usage percentage of each associated station on the communication band of the subject radio is stored by the power saving circuit. After all radios have been analyzed, control is passed to the utilization review decision process 410.

[0050] In the utilization review decision process 410, the type of multi-radio utilization review to be performed is determined, i.e., a consolidation review or a dispersion review. A consolidation review involves determining which, if any, radios on a transceiver are underutilized and therefore serve as target radios on which to consolidate sites currently associated with other radios on the transceiver. A dispersion review involves determining which, if any, radios on a transceiver are overutilized and therefore require some of the associated sites to be dispersed to other radios in the transceiver.

[0051] In the event that it is determined in decision process 410 that a merger review will be conducted, control is passed to process 412. In process 412, an underutilized radio among the radios of the transceiver is identified as a target radio for reassociating a site currently associated with at least one of the other radios of the transceiver. Control is then passed to process 414, in which it is determined whether the sites currently associated with the other radios include capabilities for supporting communications with the target radio. If they do not, control is returned to decision process 400 in decision process 416. Alternatively, if the site on the other radio has the capability to support communications with the target radio, control is passed to process 418 in decision process 416. In process 418, a resulting utilization metric (e.g., traffic or talk time) of the target radio resulting from the association of all sites currently associated with at least one other radio is predicted. If it is determined in a subsequent decision process 420 that the predicted utilization of the target radio will exceed the maximum utilization level, control is returned to decision process 400. The maximum utilization level of each radio may be expressed, for example, as a maximum airtime utilization required to support communications for all sites associated with the radio, e.g., 90%. The maximum utilization level of each radio may alternatively be expressed, for example, as a maximum traffic volume required to support communications for all sites associated with the radio, e.g., 500 Mbps. Alternatively, if it is determined in decision process 420 that the predicted utilization of the target radio is less than the maximum utilization level, control is passed to process 422. In process 422, sites currently associated with at least one other radio re-associate with the target radio. Next, in process 424, the power of at least one other radio is reduced, and control is then returned to decision process 400.

[0052] Alternatively, in the event that it is determined in decision process 410 that a decentralized review is to be conducted, control is passed to process 440. In process 440, a utilization metric, such as traffic or talk time, is determined for the target radio. Next, in decision process 442, a determination is made as to whether the utilization of the target radio exceeds a maximum utilization level for the radio. If it does not, control returns to decision process 400. If, alternatively, the utilization of the target radio does exceed the maximum utilization level for the radio, control is passed to process 444. In process 444, an underutilized radio among the other radios is identified. Next, in process 446, some stations from the target radio are reassociated with the underutilized radio among the other radios to reduce the level of the utilization metric for the target radio to below the maximum utilization level. Next, in process 448, the power consumption of the underutilized radio among the radios is increased to support communication with an increased number of stations thereon.

[0053] The components and processes disclosed herein may be implemented, alone or in combination, by hardware, circuitry, firmware, software, or a processor executing computer program code; transmit and receive path components coupled to a wireless transceiver without departing from the scope of the claimed invention.

[0054] An exemplary apparatus may include: a wireless transceiver having a plurality of components coupled to each other to form a transmit chain and a receive chain of a plurality of radios, each of the plurality of radios supporting wireless communications with associated stations on a corresponding wireless local area network (WLAN); a utilization monitoring circuit for monitoring communications between each of the plurality of radios and its associated stations; an association target circuit for identifying an underutilized radio of the radios as a target radio for reassociating a station currently associated with at least one other radio of the plurality of radios based on the monitored communications of the utilization monitoring circuit, and for initiating the reassociation of the target radio with the station currently associated with the at least one other radio; and a power backoff circuit responsive to the association target circuit to reduce power of at least one other radio of the plurality of radios. In some examples, the wireless transceiver described herein may be used as a wireless access point (WAP) transceiver or a MESH transceiver. In one example, the wireless transceiver as described above includes an association target circuit that is further used to conditionally initiate reassociation with the target radio based on at least the following predictions: a) the target radio's resulting utilization metric after reassociation will not exceed a maximum utilization level, b) the target radio's resulting aggregate talk time metric after reassociation will not exceed a maximum talk time level, or c) the target radio's resulting aggregate traffic metric after reassociation will not exceed a maximum traffic level. In addition, in conjunction with one or more of the above examples, the association target circuit can conditionally initiate reassociation with the target radio based on determining that a station currently associated with at least one other radio includes capabilities for supporting communications with the target radio.

[0055] An exemplary method may include monitoring communications between each of a plurality of radios and a site associated with it; identifying an underutilized radio of the radios as a target radio for reassociating a site currently associated with at least one other of the plurality of radios based on the monitored communications; reassociating with the target radio, the site currently associated with the at least one other radio; and reducing power of at least one other of the plurality of radios in response to at least one of identifying or initiating. The exemplary method may also include conditionally performing the reassociation based at least on a prediction that a) a resulting utilization metric of the target radio after the reassociation will not exceed a maximum utilization level, b) a resulting aggregate talk time metric of the target radio after the reassociation will not exceed a maximum talk time level, or c) a resulting aggregate traffic metric of the target radio after the reassociation will not exceed a maximum traffic level. The exemplary method may also include conditionally performing the reassociation based on a determination that a site currently associated with at least one remaining radio includes capabilities for supporting communications with the target radio. The exemplary method may also include terminating communications on at least one remaining radio or shutting down power of at least one remaining radio. The exemplary method may also include reducing a number of active multiple-input multiple-output (MIMO) communication chains supporting communications on at least one remaining radio of the plurality of radios. The exemplary method may also include identifying an underutilized radio in the plurality of radios when the utilization metric of the target radio exceeds a maximum utilization level, and reassociating stations from the target radio to the identified underutilized radio in the plurality of radios to reduce the level of the utilization metric for the target radio to below the maximum utilization level. The exemplary method may also include transmitting a transition management marker to stations currently associated with at least one other radio, the marker identifying the target radio for reassociation.

[0056] The foregoing description of the preferred embodiments of the present invention is presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations will be apparent to practitioners in the art. The scope of the present invention is intended to be defined by the following claims and their equivalents.

Claims

1. A wireless transceiver, comprising: a plurality of components coupled to each other to form transmit chains and receive chains of a plurality of radios, each of the plurality of radios supporting wireless communications with associated stations on a corresponding wireless local area network (WLAN); utilization monitoring circuitry for monitoring communications between each of the plurality of radios and its associated station; an association target circuit for identifying an underutilized one of the radios as a target radio for reassociation with a site currently associated with at least one other radio of the plurality of radios based on the monitored communications of the utilization monitoring circuit, and for initiating the reassociation of the target radio with the site currently associated with the at least one other radio; and A power backoff circuit is provided, the power backoff circuit being responsive to the associated target circuit to reduce power of the at least one other radio of the plurality of radios.

2. The wireless transceiver according to claim 1, wherein: The association target circuit is further configured to conditionally initiate the reassociation with the target radio based at least on a prediction that: a) the resulting utilization metric of the target radio after reassociation will not exceed a maximum utilization level, b) the resulting aggregate talk time metric for the target radio after reassociation will not exceed a maximum talk time level, or c) The resulting aggregate traffic metric of the target radio after reassociation will not exceed the maximum traffic level.

3. The wireless transceiver according to claim 1 or 2, wherein: The association target circuitry is further for conditionally initiating the reassociation with the target radio based on determining that the station currently associated with the at least one other radio includes capabilities for supporting communications with the target radio.

4. The wireless transceiver according to claim 1 or 2, wherein: The power backoff circuit is further configured to terminate communications on the at least one other radio of the plurality of radios.

5. The wireless transceiver according to claim 1 or 2, wherein: The power backoff circuit is further configured to reduce a number of active multiple-input multiple-output (MIMO) communication chains supporting communications on the at least one other radio of the plurality of radios.

6. The wireless transceiver according to claim 1 or 2, wherein: The association target circuit is further for identifying an underutilized radio among the plurality of radios when the utilization metric of the target radio exceeds a maximum utilization level, and reassociating sites from the target radio to the identified underutilized radio among the plurality of radios to reduce the level of the utilization metric for the target radio to below the maximum utilization level.

7. The wireless transceiver according to claim 1 or 2, wherein: The association target circuit is further for transmitting a transition management marker to the station currently associated with the at least one other radio, the marker identifying the target radio for reassociation.

8. The wireless transceiver according to claim 1 or 2, the wireless transceiver is used as one of the following: a wireless access point (WAP) transceiver or a MESH transceiver.

9. A method for operating a wireless transceiver having a plurality of radios, each of the plurality of radios supporting wireless communications with associated stations on a corresponding wireless local area network (WLAN), and comprising: monitoring communications between each radio of the plurality of radios and its associated station; identifying an underutilized one of the radios as a target radio for reassociating a site currently associated with at least one other one of the plurality of radios based on the monitored communications; re-associating with the target radio, the station currently associated with the at least one other radio; as well as Responsive to at least one of the identifying or initiating, reducing power of the at least one other radio of the plurality of radios.

10. The method for operating the wireless transceiver according to claim 9, wherein: The reduction further comprises at least one of the following: terminating communications on the at least one remaining radio; turning off power to the at least one remaining radio; or A number of active multiple-input multiple-output (MIMO) communication chains supporting communications on the at least one remaining radio of the plurality of radios is reduced.

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