Variable MIMO wireless transceiver

Abstract

The invention relates to a variable MIMO wireless transceiver. The invention discloses a multiple-input multiple-output (MIMO) wireless transceiver. The MIMO wireless transceiver is provided with N transmitting chains, N receiving chains, a bandwidth evaluation circuit, a chain division circuit and a switchable radio frequency (RF) filter bank. The bandwidth evaluation circuit evaluates utilization of both the WLAN and any remaining communication channel, and determines whether to operate the MIMO chain synchronously as a single radio or asynchronously as multiple radios. A chain division circuit divides a subset of the MIMO chains for asynchronous operation into different radio components, or combines all MIMO chains for synchronous operation into a single radio component. The switchable RF filter bank is responsive to dividing a subset of the chain into different radio components to add RF filters to the RF portion of the chain to isolate each radio component from each other, and responsive to combining all MIMO chains into a single radio component to remove all RF filters.

Description

[0001] Information about divisional applications

[0002] This application is a divisional application of the invention patent application with the invention name “Variable MIMO Wireless Transceiver”, application number 201980035883.0 and application date May 20, 2019.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims the benefit of pending U.S. non-provisional application No. 16 / 374,589, filed on April 3, 2019, entitled “TRANSMUTABLE MIMO WIRELESS TRANSCEIVER,” which is a priority application, and claims the benefit and priority of U.S. non-provisional application No. 15 / 995,104, filed on May 31, 2018, entitled “TRANSMUTABLE MIMO WIRELESS TRANSCEIVER,” and claims the benefit and priority of International Application No. PCT / US2019 / 033128, filed on May 20, 2019. Background Art 1. Technical Field

[0005] The technical field of the present invention generally relates to wireless local area networks including wireless access points (WAPs) and wireless stations, and thus particularly to multiple-input multiple-output (MIMO) wireless transceivers.

[0006] 2. Related description

[0007] 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 cables 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 contention-based standard for handling communications between multiple competing stations sharing a wireless communication medium on a selected one of 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 spokes corresponding to wireless links to each "client" device (also called a station).

[0008] After a communication channel is selected for the associated home network, access to the shared communication channel relies on a multiple access method identified as Contention Sensing 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, while all remaining nodes are able to "listen" to the primary transmission. CSMA provides a distributed random access method for sharing a single communication medium. Stations compete 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.

[0009] With the adoption of Multiple Input Multiple Output (MIMO) communications with the IEEE 802.11n standard, the introduction of 4x4 MIMO communications has greatly enhanced the communication throughput capacity on the 2.4 GHz or 5 GHz communication bands. MIMO uses multipath propagation between multiple transmit and receive antennas (also known as MIMO antenna arrays) on the WAP and the stations at either end of the communication link to multiply the capacity of the wireless communication link.

[0010] Starting with the IEEE 802.1lac standard, and in particular its "Wave 2," discrete communications with more than one target node can be performed simultaneously using the so-called multi-user (MU) MIMO capacity of a WAP with up to eight antennas supporting eight communication streams, also known as 8×8 MIMO. MU capacity was added to the standard to enable a WAP to transmit downlink communications to multiple stations simultaneously, increasing the time available for discrete MIMO video links to wireless HDTVs, tablets, and other high-throughput wireless devices. The IEEE 802.11ad standard provides coding support for communications in the 60 GHz band. The IEEE 802.11ax standard extends MU MIMO capacity to include concurrent uplinks from two or more stations to a WAP.

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

[0012] The present invention provides a method and apparatus for a wireless transceiver having a plurality of components coupled to each other to form "N" multiple-input multiple-output (MIMO) transmit and receive chains that support wireless communications with associated stations on at least one wireless local area network (WLAN). The wireless transceiver also includes: a bandwidth evaluation circuit, a chain division circuit, and a switchable radio frequency 'RF' filter bank. The bandwidth evaluation circuit evaluates the utilization of both the at least one WLAN and any remaining communication channels not utilized by the at least one WLAN, and determines based on the evaluation whether to operate the MIMO chain synchronously as a single radio component or asynchronously as multiple radio components. The chain division circuit divides a subset of the MIMO chains for asynchronous operation into different radio components that each support their own WLAN, or combines all MIMO chains for synchronous operation into a single radio component that supports communications on a single WLAN, based on the determination by the bandwidth evaluation circuit. The switchable RF filter bank is responsive to the chain partitioning circuit partitioning a subset of the chain into different radio components to switchably add RF filters to the RF portion of the transmit chain and the receive chain to isolate asynchronous transmit communications and receive communications on each radio component from each other, and is also responsive to the chain partitioning circuit combining all MIMO chains into a single radio component to remove all RF filters from the RF portion of the transmit chain and the receive chain to allow them to operate synchronously.

[0013] The present disclosure may 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 and Figure 1D are respectively a system view and a representative frequency band plan of a variable MIMO wireless transceiver according to an embodiment of the present invention;

[0017] Figure 2 yes Figures 1A to 1C A detailed hardware block diagram of the variable MIMO wireless transceiver shown; and

[0018] Figure 3 is a process flow diagram of processes associated with operating a variable MIMO wireless transceiver. DETAILED DESCRIPTION

[0019] Figures 1A to 1C and Figure 1D 2 are a system diagram and a representative frequency band plan of a representative variable multiple-input multiple-output (MIMO) wireless transceiver according to an embodiment of the present invention, respectively. Figures 1A to 1C Three different permutations of wireless transceivers are shown, respectively: one 4x4 MIMO radio; two 2x2 MIMO radios; and three radios, a 2x2 MIMO radio and two 1x1 single-input single-output (SISO) radios.

[0020] Figure 1A 1 is a system view of a flexible MIMO wireless transceiver that operates all four chains synchronously as a single 4×4 MIMO radio without any radio frequency (RF) filters in the RF portion of the transmit and receive chains (i.e., the RF portion of the analog front end). In other words, a single 4×4 MIMO radio including all Tx / Rx chains 129A-D coupled to antennas 140A-D, respectively, provides a WLAN 142 to an associated station (not shown). In this embodiment of the present invention, the flexible radio is prohibited by the IEEE 802.11ac standard and is Figure 1D172. The MIMO wireless transceiver is a wireless transceiver that is configured to operate on the 5 GHz band plan shown in FIG. 174, and specifically on one or more channels thereof, such as the 160 MHz channel 50, reference 172. The variable MIMO wireless transceiver includes: baseband circuitry 108, analog front end (AFE) circuitry 110, switchable RF filter bank 132, and conversion control circuitry 104. The baseband circuitry is coupled to the AFE circuitry to provide digital processing for downlink and uplink communications transmitted and received on all four MIMO chains 129A-D between the transceiver and its associated stations on the WLAN 142. The AFE includes, on each of its four transmit chains, a corresponding upconverter of four upconverters 112, each of which is coupled to a corresponding amplifier of four amplifiers 114. The AFE includes, on each of its four receive chains, a corresponding downconverter of four downconverters 122, each of which is coupled to a corresponding low noise amplifier (LNA) 120. The upconverter and downconverter of each transmit and receive chain are coupled to a voltage controlled oscillator (VCO) bank 124 via a switch structure 126. In a 4×4 MIMO radio conversion, all transmit and receive chains and up / downconverters are coupled to a single VCO 124D that is tunable to Figure 1D The center frequency of one or more selected channels within the 5 GHz band plan as shown. Figure 1A In the illustrated 4×4 MIMO transformation of the MIMO wireless transceiver 100, each transmit chain and receive chain 129A-D is directly coupled to a corresponding one of the antennas 140A-D. In other words, the primary filter switches 130A-D on a corresponding one of the four chains 129A-D can switchably bypass the RF filter bank 132. In an embodiment of the present invention, the transmit and receive switches 128 on each chain can switchably couple the transmit chain and the receive chain to the antenna, depending on the communication direction on the radio component, i.e., uplink or downlink. In this embodiment of the present invention, the transformation control circuit 104 is instantiated on the processor circuit 102, which executes program code 106A in the non-volatile storage device 106 to which the processor is coupled. The transformation control circuit is coupled to the baseband 108, the AFE 110, the VCO switch structure 126, the primary filter switches 130A-D and the RF filter bank to control the transformation of the wireless MIMO transceiver into Figure 1A 4×4 MIMO radio components are shown.

[0021] Figure 1Bis a system view of a variable MIMO radio transceiver, each of which operates two sets of 2 chains asynchronously relative to each other as two independent 2×2 MIMO radio components, with RF bandpass filters in the RF portion of the transmit chain and receive chain of each radio component. These RF bandpass filters isolate each of the two radio components from each other. These RF filters allow the radio components to communicate asynchronously with their respective associated stations, that is, when one 2×2 radio component is transmitting, the other 2×2 radio component can receive or transmit without interfering with each other. In the example shown, a first 2×2 MIMO radio component including Tx / Rx chains 129A-B coupled to antennas 140A-B provides WLAN 144 to associated stations (not shown), respectively. A second 2×2 MIMO radio component including Tx / Rx chains 129C-D coupled to antennas 140C-D provides WLAN 142 to associated stations (not shown), respectively. The variable radio components in this embodiment of the present invention are also Figure 1D142-144 . The 5 GHz band plan shown in FIG. 14 is shown, but in this case, the first radio operates at a frequency between 5.490 GHz-5.730 GHz on any channel within the UNII 2 extension portion of the 5 GHz band, and the second radio operates independently and asynchronously at a frequency between 5.170 GHz-5.330 GHz on any channel within the UNII 1 and UNII 2 portions of the 5 GHz band. Isolation of the two radios is achieved by switchably adding corresponding bandpass filters to the RF portion of the Tx / Rx chain of each radio by an RF filter bank. The baseband circuit is coupled to the AFE circuit to provide asynchronous processing of downlink and uplink communications transmitted and received by each radio, and the two MIMO chains each serve communications on a corresponding one of the two WLANs 142-144. The upconverters and downconverters of each transmit chain and receive chain are coupled to a voltage controlled oscillator (VCO) bank 124 via a switch structure 126. In dual radios (e.g., 2×2 and 2×2), the transmit and receive chains and up / down converters of each radio are coupled to a corresponding one of two VCOs 124A and 124D, each of which can be independently tuned to the center frequency of a different selected channel within the portion of the available frequency band of the radio. In the example shown, the VCO 124A of the first radio tunes the corresponding up / down converter to the center frequency of any channel within the UNII 2 extended portion of the 5 GHz band, while the VCO 124D of the second radio tunes the corresponding up / down converter to the center frequency of any channel within the UNII 1 and UNII 2 portions of the 5 GHz band. To allow each radio to operate asynchronously relative to each other, the RF portion of the Tx / Rx chain of each radio is coupled to a corresponding set of RF bandpass filters in the RF filter bank 132. The primary switches 130A-B on the chains 129A-B of the first radio are coupled to the UNII 2 extended RF bandpass filters 174A-B, respectively. The primary switches 130C-D on the chain 129C-D of the second radio components are coupled to the UNII 1-2 RF bandpass filters 172A-B, respectively. The switching control circuit is coupled to the baseband 108, AFE 110, VCO switch structure 126, primary filter switches 130A-D and RF filter bank to control the wireless MIMO transceiver to switch to Figure 1B1 and 2. The two 2×2 MIMO radio components shown in FIG. 1 are shown in FIG. 1. Specifically, the transform control circuit couples VCO 124A and VCO 124D to Tx / Rx chains 129A-B and 129CD, respectively. The transform control circuit also couples UNII 2 extended RF bandpass filters 174A-B to the RF portion of the first radio chain 129A-B, and couples UNII 1-2 RF bandpass filters 172A-B to the RF portion of the second radio chain 129C-D. The transform control circuit also controls the corresponding partitioning in baseband circuit 108, as will be described below. Figure 2 Shown in detail.

[0022] Figure 1C The system view of a variable MIMO wireless transceiver as three independent radios each operating asynchronously with respect to each other in three chains. The first of the three radios is a 2×2 MIMO radio. The second and third radios are 1×1 single-input single-output (SISO). Each radio has an RF bandpass filter on its chain that isolates each radio from the other. The RF bandpass filter on each radio spans Figure 1D different portions of the 5 GHz band shown. These RF filters allow the radio components to communicate asynchronously with their respective associated stations, i.e., when the first radio component is transmitting, the second radio component and the third radio component can receive or transmit without interfering with each other. In the example shown, a first 2×2 MIMO radio component including Tx / Rx chains 129A-B coupled to antennas 140A-B respectively provides WLAN 144 to associated stations (not shown). A second 1×1 SISO radio component including Tx / Rx chain 129C coupled to antenna 140C provides WLAN 142 to associated stations (not shown). A third 1×1 SISO radio component including Tx / Rx chain 129D coupled to antenna 140D provides WLAN 146 to associated stations (not shown). The variable radio components in this embodiment of the present invention are also Figure 1D142-146. The WLANs 142-146 of FIG. 146 are shown in FIG. 14A and 14B. The WLANs 142-146 of FIG. 14B are shown in FIG. 14C. The WLANs 142-146 of FIG. 14A are shown in FIG. 14B. The WLANs 142-146 of FIG. 14B are shown in FIG. 14C ... In the example shown, the VCO 124A of the first radio tunes the corresponding up / down converter to the center frequency of any channel within the UNII 2 extended portion of the 5 GHz band. The VCO 124C of the second radio tunes the corresponding up / down converter to the center frequency of any channel within the UNII 3 portion of the 5 GHz band. The VCO 124D of the third radio tunes the corresponding up / down converter to the center frequency of any channel within the UNII 1-2 portion of the 5 GHz band. To allow each of the three radios to operate asynchronously relative to each other, the RF portion of the Tx / Rx chain of each radio is coupled to a corresponding set of RF bandpass filters in the RF filter bank 132. The primary switches 130A-B of the filter bank on the chains 129A-B of the first radio and the switch structure 134 of the filter bank couple those chains to the UNII 2 extended RF bandpass filters 174A-B, respectively. The primary switch 130C on the chain 129C of the second radio and the switch structure 134 of the filter bank couple the chain to the UNII 3RF bandpass filter 176B. The primary switch 130D on the chain 129D of the third radio and the switch structure 134 of the filter bank couple the chain to the UNII 1-2RF bandpass filter 172B. The conversion control circuit is coupled to the baseband 108, AFE 110, VCO switch structure 126, primary filter switches 130A-D and RF filter bank to control the wireless MIMO transceiver to convert to Figure 1CThe three 2×2, 1×1, 1×1 radio components shown. Specifically, the transform control circuit couples VCO 124A to Tx / Rx chain 129A-B, couples VCO 124C to Tx / Rx chain 129C, and couples VCO 124D to Tx / Rx chain 129D. The transform control circuit also couples the RF bandpass filters. In the example shown: UNII 2 extended RF bandpass filters 174A-B to the RF portion of the first radio chain 129A-B; UNII 3 RF bandpass filters 176B to the RF portion of the second radio chain 129C; and UNII 1-2 RF bandpass filters 172B to the RF portion of the third radio chain 129D. The transform control circuit also controls the corresponding partitioning in the baseband circuit 108, as will be described below. Figure 2 In alternative embodiments of the invention, the RF filters in the filter bank may be high pass filters and low pass filters with breakpoints between UNII bands that are used to isolate communications on one radio from another without departing from the scope of the claimed invention.

[0023] Figure 1D A representative Unlicensed National Information Infrastructure 'UNII' radio band used by IEEE 802.11a devices is shown, also known as the 5 GHz band 170. In an embodiment of the present invention, the variable MIMO wireless transceiver 100 supports this band plan. The band plan 170 depicts a number of orthogonal frequency division multiplexing (OFDM) channels, specifically: a 40 MHz channel, an 80 MHz channel, and a 160 MHz channel. These channels are called orthogonal frequency division multiplexing (OFDM), where each channel includes multiple OFDM subchannels or tones. The band plan includes the aforementioned UNII 1-2, UNII 2 extension, and UNII 3 portions and different 40 MHz, 80 MHz, and 160 MHz channels for each of them.

[0024] Figure 2 yes Figures 1A to 1C Detailed hardware block diagram of the variable MIMO wireless transceiver shown, and in particular, the transceiver forms a transformation of two 2×2 MIMO radios, also as shown Figure 1BAs shown. The MIMO wireless transceiver 100 may be instantiated on one or more very large scale integrated circuit (VLSI) chips. The MIMO wireless transceiver is identified as a 4×4 (MIMO) WAP that supports up to 4 discrete communication streams on its MIMO antenna arrays 140A-D. The transceiver is coupled to the Internet via an Ethernet media access control (EMAC) interface 222 through a cable, fiber optic, or digital subscriber line (DSL) backbone connection (not shown). The packet bus 220 couples the EMAC to a Wi-Fi baseband 108 and an analog front end (AFE) 110 that include multiple components for forming transmit and receive paths / chains for wireless uplink and downlink communications. The MIMO transceiver 100 includes: a MIMO baseband 108, an AFE, a transform control circuit 104, an RF filter bank 132, main filter switches 130A-D, and antennas 140A-D.

[0025] In the baseband section 108, 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 communications or multi-user communications with associated stations. The AFE 110 handles the up-conversion on each transmit chain of wireless transmissions initiated in the baseband. The AFE also handles the down-conversion of the received signals on the receive chain and passes them to the baseband for further processing.

[0026] emission: The transmit path / chain includes the following discrete and shared components. The Wi-Fi medium access control (WMAC) component 224 includes: a hardware queue 224A for each downlink and uplink communication flow; an encryption and decryption circuit 224B for encrypting and decrypting downlink and uplink communication flows; a medium access circuit 224C for performing clear channel assessment (CCA) and making exponential random backoff and retransmission decisions; and a packet processor circuit 224D for packet processing of communication flows. The WMAC component has a node table 224E that lists each node / station on the WLAN, the station's capacity, the corresponding encryption key, and the priority associated with its communication traffic.

[0027] Each probe or data packet for wireless transmission to one or more stations on a transmit chain is framed in framer 226. Next, each stream is scrambled and encoded in scrambler and encoder 228 and then demultiplexed into up to four streams in demultiplexer 230. The demultiplexer operates under the control of the switching control circuit to place the communications of each radio component on the corresponding transmit chain assigned to it by the switching control circuit. Figure 2 In the example above, the transceiver Figure 1B The dual 2×2 configuration discussed in is shown. Figure 2The 4×4 MIMO transceiver is transformed into two asynchronous 2×2 MIMO radio components. Figure 2 , the downlink communications for the second 2×2 radio are placed on the chain assigned to that radio, i.e., chain 129C-D, by demultiplexer 230. Each stream is then interleaved and mapped in a corresponding one of interleavers 232 and mappers 234 on the corresponding chain. Next, the downlink transmissions are spatially mapped in a partitionable spatial mapper 236 with a corresponding beamforming matrix, also referred to as a precoding matrix 'Q' (not shown). The spatial mapper is considered partitionable because it can handle spatial mapping for all four transmit chains when the transceiver is operating as a single 4×4 MIMO radio, or it can be partitioned to independently spatially map the chains assigned to each radio.

[0028] The partitionable space mapper 236 obtains M Tx symbols (by vector X Mx1 Represented) and mapped to vector Y Nx1 , which is then transmitted by the N assigned Tx chains. This mapping is done by the matrix S NxM Execution, where matrix coefficients are calculated based on different Tx scenarios.

[0029] Y Nx1 =S NxM X Mx1

[0030] Here M is less than or equal to N. In the case of a divisible spatial mapper, a given NxM dimensional spatial mapper, e.g., 4×4, is partitioned into multiple spatial mappers, e.g., 2×2 and 2×2, each of which performs the operations described in the above equations, but with lower values ​​of M and N. The values ​​of M and N for each partitioned spatial mapper are based on the MIMO capacity of the radio, e.g., the number of chains assigned to the radio by the transform control circuit 104. The spatial mapping stream from the divisible spatial mapper is input to an inverse discrete Fourier transform (IDFT) component 238 on a corresponding chain (e.g., chains 129C-D of the corresponding radio) for conversion from the frequency domain to the time domain and subsequent transmission on a corresponding one of the transmit chains (e.g., chains 129C-D in the AFE 110). In an embodiment of the present invention, the partitionable spatial mapper 236 is responsive to the partitioning of the MIMO chains to spatially map the transmit communications on each radio component's chain independently of each other, and is also responsive to combining all MIMO chains into a single radio component to spatially map the transmit communications on all MIMO chains of the single radio component together with each other.

[0031] The IDFT on each transmit path / chain is coupled to a corresponding one of the transmit path / chain components in the AFE 110. Specifically, each IDFT 238 is coupled to an associated one of the digital-to-analog converters (DACs) 240 for converting digital transmissions into analog transmissions. Next, each transmit chain of the main radio is filtered in a filter 242 (e.g., a bandpass filter) for controlling the channel to be wirelessly transmitted. After filtering, the transmission is up-converted to the center frequency of the selected channel of the 5 GHz band in the up-converter 112. Each up-converter is coupled to a voltage controlled oscillator (VCO) group 124 to up-convert the transmission to the appropriate center frequency of the selected channel. The switch structure 126 couples the up-converter on the chain assigned to the first radio component to the VCO 124A, and couples the up-converter on the chain assigned to the second radio component to the VCO 124D. Next, one or more amplification stages are provided on each chain by the power amplifier 114. Each power amplifier may be switchably connected directly or through filter bank 132 to a corresponding one of antennas 140A-D, depending on the configuration of the transceiver. Figure 2 In the illustrated variation, the transceiver operates as a dual radio, in which case the primary filter switches 130A-B couple the chain 129A-B of the first radio to the UNII 2 extended bandpass filter in the RF filter bank, and the primary filter switches 130C-D couple the chain 129C-D of the second radio to the UNII 1-2 bandpass filter in the RF filter bank. Alternatively, in the case where the variable MIMO wireless transceiver operates as a single 4×4 MIMO radio, the primary filter switches 130A-D bypass the filter bank and couple the power amplifier 114 of each chain directly to a corresponding one of the antennas 140A-B.

[0032] take over: The receive path / chain includes the following discrete and shared components. Communications received on the transceiver's MIMO antenna array 108 undergo RF processing, including down-conversion in AFE 110. Each antenna 140A-D is switchably connected directly or through a filter bank 132 to a corresponding one of the low noise amplifiers 120, depending on the transceiver's transformation. Figure 2In the illustrated variation, the transceiver operates as a dual radio, in which case primary filter switches 130A-B couple chain 129A-B of the first radio to the UNII 2 extended bandpass filters in the RF filter bank, and primary filter switches 130C-D couple chain 129C-D of the second radio to the UNII 1-2 bandpass filters in the RF filter bank. Alternatively, in the case where the variable MIMO wireless transceiver operates as a single 4×4 MIMO radio, primary filter switches 130A-D bypass the filter bank and couple the antenna of each chain directly to a corresponding one of the low noise amplifiers 120. Site uplinks received on antennas 140A-D are amplified in a corresponding one of the low noise amplifiers 120. Figure 2 In the dual radio conversion shown, one radio component (e.g., the second radio component) may be transmitting while the other radio component (e.g., the first radio component) is receiving. In the example shown, the first radio component is receiving on the chain 129A-B. After amplification, the received communication on the first radio component is down-converted in a corresponding one of the down-converters 122. The down-converter of the first radio component is coupled to the VCO 124A in the VCO group 124 via the switch structure 126. The down-converter of the second radio component is coupled to the VCO 124D in the VCO group 124 via the switch structure 126. The received signal of each chain is then filtered in a corresponding one of the channel filters 250 (e.g., bandpass filters) for controlling the channel on which the wireless reception will occur. Next, the down-converted analog signal on each chain is digitized in a corresponding one of the analog-to-digital converters (ADCs) 252.

[0033] The receive processing at the baseband stage includes the following discrete and shared components. The digital output from each ADC is passed to a corresponding one of the discrete Fourier transform (DFT) components 254 in the baseband 108 for conversion from the time domain to the frequency domain. A divisible equalizer 256 for mitigating channel impairments is coupled to the output of the DFT 254. The equalizer is considered divisible because it can equalize the chains assigned to each radio component independently of each other. The divisible equalizer takes input symbols from all receive chains of the radio component (represented by vector Y) and generates equalized symbols (represented by vector X) by removing the effects of the channel H. In the case of a linear minimum mean square error 'LMMSE' equalizer, the equalizer uses an equalization matrix W defined as follows:

[0034]

[0035] Here H is the channel matrix of dimension N×M (for a receiver with N Rx chains, receiving symbols with M streams), and σ 2= , represents the Rx noise variance. For the H matrix, the W matrix dimension is M×N. The equalizer 256 uses the equalizer matrix to perform the following operation to generate the vector X:

[0036] X Mx1 =W MxN Y Nx1

[0037] Here M is less than or equal to N. In the case of a divisible equalizer, the same equalizer circuit is divided among multiple equalizers, where each equalizer performs the operations mentioned in the above equations, but with lower values ​​of M and N. The value of M and N for each divided equalizer is based on the MIMO capabilities of the radio. In an embodiment of the present invention, the divisible equalizer 256 is responsive to the division of the MIMO chains to equalize the receive communications on each radio's chain independently of each other, and is also responsive to combining all MIMO chains into a single radio to equalize the receive communications on all MIMO chains of the single radio together with each other.

[0038] The streams received at the output of the divisible equalizer are subjected to demapping and deinterleaving in a corresponding one of the demapper 258 and the deinterleaver 260. Next, the received streams are multiplexed in the order of their associated radio components in the multiplexer 262, and decoded and descrambled in the decoder and descrambler component 264, and then deframed in the deframer 266. Figure 2 In the example shown, the first radio is receiving an uplink on chain 129A-B, and the corresponding streams are multiplexed by multiplexer 262 and decoded, descrambled, and deframed together. The received communication is then passed to WMAC component 224, where it is decrypted by decryption circuit 224B and placed in the appropriate upstream hardware queue 224A of the corresponding radio for upload to the Internet. In the event that two radios are receiving different uplinks simultaneously, each radio uplink will be processed separately by the WMAC component.

[0039] Table 270 shows possible transmit and receive scenarios supported by the flexible MIMO wireless transceiver when operating as two independent asynchronous radio components.

[0040] In this embodiment of the present invention, the change control circuit 104 is instantiated on the processor circuit 102, which executes the program code 106A in the non-volatile storage device 106 to which the processor is coupled. The change control circuit is coupled to the baseband 108, AFE 110, VCO switch structure 126, primary filter switches 130A-D and RF filter bank to control the wireless MIMO transceiver to change to Figure 2Two 2x2 MIMO radio components are shown. The switch control circuit includes a bandwidth estimation circuit 104A, a chain division circuit 104D, and a filter control circuit 104E. The bandwidth estimation circuit includes both a WLAN estimation circuit 104B and a channel estimation circuit 104C.

[0041] The bandwidth assessment circuit 104A assesses the utilization of the WLAN together with any remaining communication channels provided by the radio that are not utilized by the WLAN, and determines based on the assessment whether to operate the MIMO chain synchronously as a single radio or asynchronously as multiple radios. In an embodiment of the present invention, the WLAN assessment circuit 104B of the bandwidth assessment circuit assesses the utilization of the WLAN, including the throughput of each station and the capacity of each associated station. In another embodiment of the present invention, the channel assessment circuit 104C of the bandwidth assessment circuit assesses the utilization of any remaining communication channels, including interference to the remaining channels generated by radar or by other wireless transceivers.

[0042] Chain partitioning circuitry 104D partitions a subset of MIMO chains for asynchronous operation into different radio components, each supporting their own WLAN, or combines all MIMO chains for synchronous operation into a single radio component supporting communications on a single WLAN, based on the determination of the bandwidth assessment circuitry. In an embodiment of the present invention, chain partitioning circuitry determines the number of MIMO chains in the subset of MIMO chains for each different radio component based at least on the capabilities of the associated sites (e.g., their support for MIMO, their number of antennas, etc.).

[0043] The switchable radio frequency 'RF' filter bank 132 and primary filter switches 130A-D are responsive to the chain partitioning circuitry partitioning a subset of the chains into different radio components to switchably add RF filters to the RF portions of the transmit and receive chains to isolate asynchronous transmit and receive communications on each radio component from each other, and are also responsive to the chain partitioning circuitry combining all MIMO chains into a single radio component to remove all RF filters from the RF portions of the transmit and receive chains to allow synchronous operation thereof. Figure 1B and Figure 2The switchable RF filter bank in the illustrated embodiment of the present invention includes a first group of RF bandpass filters each spanning a first group of communication channels (e.g., channels within the UNII 1-2 portion of the 5 GHz band plan) and a second group of RF bandpass filters each spanning a second group of communication channels different from the first group (e.g., the UNII 2 extension portion of the 5 GHz band plan). The switchable RF filter bank is responsive to the chain division circuitry dividing a subset of chains into two different radio components to switchably add one of the first group of RF bandpass filters to the RF portion of each chain in the subset of chains of one of the two radio components, and to switchably add one of the second group of RF bandpass filters to each chain in the subset of chains of the other of the two radio components to isolate asynchronous transmit communications and receive communications on each radio component from each other. The switchable RF filter bank is also responsive to the chain division circuitry combining all MIMO chains into a single radio component to remove the first group of RF bandpass filters and the second group of RF bandpass filters from the RF portions of all MIMO transmit chains and receive chains to allow them to operate synchronously.

[0044] Therefore, in an embodiment of the present invention, a voltage controlled oscillator (VCO) group 124 including independently tunable VCOs can be switchably connected to the transmit chain and the receive chain via a switch structure 126 for selecting a center frequency, and the VCO group responds to the division of the MIMO chains to switchably connect the independently tunable VCOs to the transmit chain and the receive chain of each radio component, and also responds to the combination of all MIMO chains to switchably connect a single VCO to all MIMO chains of a single radio component.

[0045] In alternative embodiments of the present invention, the wireless transceiver may operate as: a Wireless Access Point (WAP) transceiver or a MESH transceiver without departing from the scope of the claimed invention.

[0046] Figure 3 is a process flow diagram of a process associated with operating a variable MIMO radio transceiver. Processing begins with the configuration of all "N" MIMO chains to operate synchronously as a single radio or first radio in process 300. Next, in process 302, one or more communication channels are selected for the first radio. Then, in process 304, a WLAN for the first radio (also referred to as a first WLAN) is initiated with associated stations on the one or more communication channels selected in the previous process. Control then passes to process 306 to continue supporting ongoing WLAN communications.

[0047] Next, in the bandwidth evaluation block 310, the following processes are performed. In process 312, the performance of the radio component WLAN is evaluated. This includes overall throughput and per-link throughput, site capacity including MIMO support and the number of antennas and streams, and site distance or received signal strength indicator (RSSI). Next, in process 314, the availability of any additional portions of the communication band on which the radio component can operate is determined. This evaluation may involve determining interference from radar or from another WLAN and available airtime on various portions of the band plan (e.g., the UNII portion of the 5 GHz band plan). Next, control is passed to decision process 320.

[0048] In decision process 320, a determination is made whether to partition the MIMO chains into independent radios that may operate asynchronously relative to each other, to reunite all MIMO chains into a single radio whose chains operate synchronously relative to each other, or to leave the current transformation of the variable MIMO radio transceiver, i.e., the number of radios, unchanged. The determination is based on the bandwidth evaluation block of process 310. Generally, if there is an additional UNII portion of the band plan available, then increasing the number of radios instantiated by the variable MIMO radio transceiver will be beneficial to the overall throughput of the variable MIMO radio transceiver, and vice versa, where the available bandwidth is slightly reduced and the number of radios is currently instantiated.

[0049] If it is determined in decision process 320 that the current transformation of the variable MIMO wireless transceiver is acceptable based on evaluation 310 , control returns to process 306 .

[0050] Alternatively, if it is determined in decision process 320 to continue instantiating multiple radio components that operate asynchronously with respect to each other, control is passed to process 322. In process 322, subsets of the MIMO chains of the transceiver, for example, subsets X and Y, where X+Y=N, or subsets X, Y, and Z, where X+Y+Z=N; are identified for reuse to support operation of two or more asynchronous radio components. The number of subsets identified and the number allocated to each chain may be based on the capacity of the site and whether the current throughput of the supported WLAN has increased or decreased as determined in process 312. The number of subsets identified may also be based on the presence or absence of additional available portions of the band plan (e.g., the UNII portion of the 5 GHz band plan). The number of subsets identified may also depend on the number of available bandpass filters.

[0051] Next, in decision process 324, a determination is made as to whether to transform the MIMO wireless transceiver to add another radio component or to transform the MIMO wireless transceiver to remove a radio component.

[0052] If it is determined in decision process 324 that a radio is to be added, control is passed to process 330. In process 330, RF bandpass filters are switchably added to the RF portion of the MIMO chain of each radio, including the MIMO chain of the added radio. These RF filters isolate the asynchronous communications of the radios (e.g., the first radio and the second radio) from each other. Next, in process 332, independently tunable VCOs are switchably added to the AFE portion of the chain assigned to each radio, wherein each VCO is tunable to the center frequency of the communication channel of the radio. Then, control is passed to process 334, wherein the baseband portion of each radio is divided to process the MIMO chain of each radio independently of each other. Then, in process 336, any reassociation of the added radio with a portion of the site previously associated with the existing WLAN provided by the existing radio is implemented. In an embodiment of the present invention, this can be achieved by transmitting an 802.11ac band switch notification or an 802.11ad fast session transmission to the site to be reassociated with the added radio. Control then returns to process 306 .

[0053] If it is determined in decision process 324 to remove the radio component, control is passed to decision process 340. In decision process 340, the number of existing radio components is determined. If the existing number is 2, control is passed to process 350 for transforming the MIMI wireless transceiver into a single radio component that operates all chains synchronously. Alternatively, if the number of existing radio components is determined to be three or more in decision process 340, control is passed to process 341 to initiate the process of removing one of three or more existing radio components. In process 341, the radio component to be removed is identified. Next, in process 342, the RF filter is switchably removed from the chain of the identified radio component. Then, in process 344, the VCO of the identified radio component is switchably removed. Next, in process 346, any baseband partitioning instantiated to support the identified radio component is removed. This includes corresponding partitioning in a divisible equalizer and a divisible space mapper. Then, in process 348, any re-association with the remaining radios of the station that were previously associated with the WLAN provided by the radio identified for removal is achieved. In an embodiment of the present invention, this may be achieved by transmitting an 802.11ac band switch notification or an 802.11ad fast session transmission to the station to be re-associated with the remaining radios. Control then returns to process 306.

[0054] Alternatively, if it is determined in decision process 320 to return the radio to synchronized operation of all chains, control is passed to process 350. In process 350, the RF bandpass filter is switchably removed from the RF portion of the MIMO chain of each radio to allow all MIMO chains to synchronize as one radio to utilize synchronized operation of all MIMO chains of the variable MIMO radio transceiver. Control is then passed to process 352 in process 344, and a single tunable VCO is switchably reconnected to all MIMO chains to tune all chains to the center frequency of the communication channel of the radio. Control is then passed to process 354, where baseband processing partitioning is removed, such as partitioning in a divisible spatial mapper and a divisible equalizer, thereby allowing all chains to synchronize as a single radio supporting communications on a WLAN provided by the radio. Then, in process 356, any reassociation of the first radio with a site previously associated with a WLAN provided by a second radio or other radio is achieved. In one embodiment of the invention, this may be accomplished by transmitting an 802.11ac band switch notification or an 802.11ad fast session transmission to the station that will reassociate with the single remaining radio. Control then returns to process 306.

[0055] In another embodiment of the invention, the return of the variable MIMO wireless transceiver to synchronized operation of all chains as a single radio may be accomplished not with the removal of all RF bandpass filters, but with switchable addition of the same bandpass filters to some or all chains.

[0056] An exemplary wireless transceiver may include: two or more components coupled to each other to form "N" multiple-input multiple-output (MIMO) transmit chains and receive chains that support wireless communications with associated stations on at least one wireless local area network (WLAN); bandwidth assessment circuitry to assess utilization of both the at least one WLAN and any remaining communication channels not utilized by the at least one WLAN and to determine, based on the assessment, whether to synchronously operate the MIMO chains as a single radio component or to asynchronously operate the MIMO chains as multiple radio components; and chain partitioning circuitry to allocate the MIMO chains for asynchronous operation to the MIMO chains based on the determination by the bandwidth assessment circuitry. A subset of the chains are divided into different radio components each supporting its own WLAN, or all MIMO chains for synchronous operation are combined into a single radio component supporting communication on a single WLAN; and a switchable radio frequency (RF) filter bank, which is responsive to the division of the subset of chains into different radio components by the chain division circuit to switchably add RF filters to the RF portion of the transmit chain and the receive chain to isolate asynchronous transmit and receive communications on each radio component from each other, and is also responsive to the combination of all MIMO chains into a single radio component by the chain division circuit to remove all RF filters from the RF portion of the transmit chain and the receive chain to allow them to operate synchronously. One or more components coupled to each other to form "N" MIMO receive chains may include a divisible equalizer, which is responsive to the division of the MIMO chains by the chain division circuit to equalize the receive communications on the chain of each radio component independently of each other, and is also responsive to the combination of all MIMO chains to equalize the receive communications on all MIMO chains of the single radio component together with each other. One or more components coupled to each other to form "N" MIMO transmit chains may include a partitionable spatial mapper that is responsive to partitioning of the MIMO chains by the chain partitioning circuit to spatially map transmit communications on each radio component's chain independently of each other, and is also responsive to the combination of all MIMO chains to spatially map transmit communications on all MIMO chains of a single radio component together with each other. The wireless transceiver may also include bandwidth assessment circuitry for assessing utilization of at least one WLAN, including per-site throughput and capacity of each associated site. The wireless transceiver may also include bandwidth assessment circuitry for assessing utilization of any remaining communication channels, including for interference to the remaining channels generated by radar or by other wireless transceivers.

[0057] An exemplary method for operating a wireless transceiver may include providing two or more components coupled to each other to form "N" multiple-input multiple-output (MIMO) transmit and receive chains that support wireless communications with associated stations on at least one wireless local area network (WLAN); determining whether to operate the MIMO chains synchronously as a single radio or asynchronously as multiple different radios, each different radio having a different subset of the "N" transmit and receive chains; in response to determining in the act of determining to operate the subset of the MIMO chains as different radios, switchably adding a radio frequency (RF) filter to an RF portion of each transmit and receive chain assigned to a given radio to isolate asynchronous transmit communications and receive communications on each radio from each other; and in response to determining in the act of determining to operate the MIMO chains synchronously as a single radio, switchably removing the RF filter from the RF portion of each transmit and receive chain. The providing may include providing a divisible equalizer and, in response to the determining, equalizing receive communications on the receive chain of each radio independently of each other in corresponding partitions of the divisible equalizer. The providing may include providing a partitionable spatial mapper and in response to determining, in a corresponding partition of the partitionable spatial mapper, mapping the transmit communication space independently of each other on the transmit chain of each radio component. The providing may include: providing a voltage controlled oscillator (VCO) group, the VCO group including independently tunable VCOs switchably connected to the transmit chain and the receive chain for selecting their center frequencies; and switchably connecting the independently tunable VCOs to the transmit chain and the receive chain of each radio component in response to determining. The determining and switchably adding may also include: determining to asynchronously operate the MIMO chain as two different radio components, each radio component having a different subset of "N" transmit chains and receive chains; and in response to determining to operate the MIMO chain as two different radio components, switchably adding one of the first group of RF bandpass filters, each spanning the first group of communication channels, to the RF portion of each chain in the subset of the chain of one of the two radio components, and adding one of the second group of RF bandpass filters, each spanning the second group of communication channels, to the RF portion of each chain in the subset of the chain of the other of the two radio components.

[0058] 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.

[0059] The above 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 limited by the following claims and their equivalents.

Claims

1. A wireless transceiver, comprising: a plurality of components coupled to each other to form "N" multiple-input multiple-output (MIMO) transmit and receive chains that support wireless communications with associated stations on at least one wireless local area network (WLAN); chain partitioning circuitry for partitioning a subset of the MIMO chains for asynchronous operation into different radio components each supporting its own WLAN, or combining all MIMO chains for synchronous operation into a single radio component supporting communications on a single WLAN; and a switchable radio frequency (RF) filter bank responsive to partitioning a subset of the chains into different radio components by the chain partitioning circuit to switchably add RF filters to the RF portions of the transmit and receive chains to isolate the asynchronous transmit and receive communications on each radio component from each other, and also responsive to combining all MIMO chains into a single radio component by the chain partitioning circuit to remove all RF filters from the RF portions of the transmit and receive chains to allow synchronous operation thereof.

2. The wireless transceiver according to claim 1, further comprising: The plurality of components coupled to each other to form "N" MIMO transmit and receive chains include; a voltage controlled oscillator (VCO) group including independently tunable VCOs switchably connected to the transmit and receive chains for selecting center frequencies thereof, and the VCO group is responsive to the division of the MIMO chains by the chain division circuit to switchably connect the independently tunable VCOs to the transmit and receive chains of each radio section, and is also responsive to the combination of all MIMO chains to switchably connect a single VCO to all of the MIMO chains of the single radio section.

3. The wireless transceiver according to any one of claims 1 to 2, further comprising: the switchable RF filter bank including a first set of RF bandpass filters each spanning a first set of communication channels and a second set of RF bandpass filters each spanning a second set of communication channels different from the first set of communication channels, and the switchable RF filter bank is responsive to the chain partitioning circuit dividing the subset of the chains into two different radio components to switchably add one of the first set of RF bandpass filters to the RF portion of each chain in the subset of chains of one of the two radio components and to switchably add one of the second set of RF bandpass filters to each chain in the subset of chains of the other of the two radio components to isolate asynchronous transmit communications and receive communications on each radio component from each other; as well as The switchable RF filter bank is also responsive to combining all MIMO chains into a single radio component by the chain splitting circuit to remove the first set of RF bandpass filters and the second set of RF bandpass filters from the RF portions of all of the MIMO transmit and receive chains, thereby allowing them to operate synchronously.

4. The wireless transceiver according to any one of claims 1 to 3, further comprising: The switchable RF filter bank includes a plurality of groups of RF bandpass filters, wherein each RF bandpass filter in a group spans the same communication channel and each group of RF bandpass filters spans different communication channels from one another; and the switchable RF filter bank is responsive to the chain partitioning circuit dividing a subset of the chain into different radio components to switchably add the RF bandpass filters in each group to the RF portion of the chain of each radio component to isolate the asynchronous transmit communications and receive communications on each radio component from one another; and The switchable RF filter bank is also responsive to combining all MIMO chains into a single radio by the chain splitting circuit to remove the RF bandpass filters from the RF portions of all the MIMO transmit and receive chains, thereby allowing synchronous operation thereof.

5. The wireless transceiver according to any one of claims 1 to 4, further comprising: The chain partitioning circuit is further configured to determine a number of MIMO chains in the subset of MIMO chains for each different radio component based at least on the capacity of the associated site.

6. The wireless transceiver according to any one of claims 1 to 5, the wireless transceiver being used as one of: a wireless access point (WAP) transceiver or a MESH transceiver.

7. A method for operating a wireless transceiver, and the method comprising: providing a plurality of components coupled to each other to form "N" multiple-input multiple-output (MIMO) transmit and receive chains that support wireless communications with associated stations on at least one wireless local area network (WLAN); determining whether to operate the MIMO chains synchronously as a single radio or asynchronously as a plurality of different radios, each different radio having a different subset of the "N" transmit and receive chains; responsive to a determination in said determining to operate a subset of said MIMO chains as distinct radios, switchably adding a radio frequency 'RF' filter to an 'RF' portion of each transmit chain and receive chain assigned to a given radio to isolate said asynchronous transmit and receive communications on each radio from one another; as well as In response to determining in the determining to synchronously operate the MIMO chains as a single radio, the RF filters may be switchably removed from the RF portion of each transmit chain and receive chain.

8. The method for operating the wireless transceiver of claim 7, wherein the determining and the switchably adding further comprise: determining to asynchronously operate the MIMO chains as an integer "M" number of radios, each radio having a different subset of the "N" number of transmit and receive chains; as well as RF bandpass filters are switchably added to the RF portions of the MIMO transmit and receive chains of each of the M radio components, wherein the RF bandpass filters of each radio component span different communication channels from each other to isolate the asynchronous transmit and receive communications of each of the M radio components from each other.

9. The method for operating the wireless transceiver according to any one of the preceding claims, wherein the determining further comprises: A number of MIMO chains in the subset of MIMO chains for each different radio component is determined based at least on the capabilities of the associated site.

10. A computer program which, when executed by a computer, is operative to perform the method according to any one of claims 7 to 9.

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