Patent Description:
According to <CIT>, a wireless node selects modulation coding schemes (MCS) and number of spatial streams for transmitting data to devices via a MU-MIMO transmission based on the total number of spatial streams.

<CIT> describes that transmission parameters are determined for communication between apparatuses. These transmission parameters may specify, for example, a number of spatial streams, a bandwidth, and a transmission rate.

<CIT> discusses that an accurate total error rate performance can be measured using a computed error vector magnitude per stream. Using this error vector magnitude, the receiver or the transmitter can advantageously generate an optimized modulation and coding scheme that corresponds to a specific number of streams, modulation and coding rate for the transmitter.

The invention is set forth in the independent claims. Specific embodiments are presented in the dependent claims.

This summary is provided to introduce simplified concepts of mesh network range extension and reliability enhancement through lower order MIMO spatial streams.

The simplified concepts are further described below in the Detailed Description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining the scope of the claimed subject matter.

In aspects, methods, devices, systems, and means for wireless communication in a wireless mesh network by a wireless mesh router, in particular, for improving wireless communication range and reliability in a wireless mesh network by a wireless mesh router, describe the mesh router measuring an indication of a link quality between the wireless mesh router and another wireless device. The wireless mesh router determines a number of spatial streams for the wireless communication based on the measured indication of link quality and uses the determined number of spatial streams to select a channel bandwidth and a Modulation and Coding Scheme (MCS) for the wireless communication. The wireless mesh router configures a wireless transceiver for the wireless communication using the determined number of spatial streams, the selected channel bandwidth, and the selected MCS. The wireless mesh router may communicate with the other wireless device using the configured wireless transceiver.

According to an aspect, a wireless mesh (access) router comprises one or more wireless transceivers; and a processor and memory system that stores a rate controller application and, when executing the rate controller application, performs the method of any aspect or embodiment described herein.

Aspects of mesh network range extension and reliability enhancement through lower order MIMO spatial streams are described with reference to the following drawings. The same numbers are used throughout the drawings to reference like features and components:.

Wi-Fi mesh network routers suffer from limited range and reliability issues due to link budget limitations when an NxN Multiple-Input, Multiple-Output (MIMO) channel is fully utilized to carry N spatial data streams in order to maximize network data throughput. These range and reliability issues are especially severe for the <NUM>. 11ax mesh routers with Wi-Fi <NUM> backhaul where transmit power is significantly reduced by the regulatory requirements for Low Power Indoor (LPI) <NUM>. 11ax 6E devices. The LPI transmit power reduction when using a Modulation and Coding Scheme <NUM> (MCS0) varies from <NUM> dB to <NUM> dB, depending on the channel bandwidth (e.g., <NUM> or <NUM> channel bandwidth).

By improving rate adaptation techniques in Wi-Fi mesh routers, consistency of coverage range can be improved. Overcoming the range and reliability issues for <NUM>. 11ax mesh routers with Wi-Fi <NUM> backhaul can increase the cost and reduce the options for maintaining a small form factor for a mesh router. For example, increasing the number of transmit antennas, N, to three or four antennas (N=<NUM> or N=<NUM>) adds hardware cost to a mesh router and affects the form factor of the product design as compared to using two antennas (N=<NUM>). Changes in rate adaptation techniques can improve coverage without increasing the cost or reducing the options for maintaining a small form factor for a mesh router.

<FIG> illustrates an example environment <NUM>, which includes multiple mesh routers <NUM>, illustrated as mesh router <NUM>, mesh router <NUM>, and mesh router <NUM>. The mesh routers <NUM> collectively provide a Wi-Fi network <NUM> that provides wireless connectivity to one or more client devices <NUM>. Each client device <NUM> can communicate with one or more mesh routers <NUM> through one or more wireless communication links <NUM>, illustrated as wireless communication link <NUM> and wireless communication link <NUM>. In this example, the client device <NUM> is implemented as a smartphone. Although illustrated as a smartphone, the client device <NUM> may be implemented as any suitable computing or electronic device, such as a mobile communication device, gaming device, media device, laptop computer, desktop computer, tablet computer, smart appliance, and the like. The mesh routers <NUM> may implement one or more Wireless Local Area Network (WLAN) technologies, such as IEEE <NUM>, IEEE <NUM>. 11a, IEEE <NUM>. 11b, IEEE <NUM>, IEEE <NUM>. 11n (Wi-Fi <NUM>), IEEE <NUM>. 11ac (Wi-Fi <NUM>), IEEE <NUM>. 11ax (Wi-Fi <NUM>, Wi-Fi 6E), or future evolutions thereof.

The mesh routers <NUM> are connected by wired (e.g., Ethernet) or wireless backhaul links (mesh links) at <NUM>, <NUM>, and <NUM> to send network traffic between client devices <NUM> and/or between client devices and the Internet <NUM> and remote service(s) <NUM>. For example, one or more mesh routers, such as the mesh router <NUM> include a network interface to connect to the Internet <NUM>, such as via a cable modem or DSL modem and a corresponding communication link <NUM>.

<FIG> illustrates an example device diagram <NUM> of the multiple mesh routers <NUM> and the client device <NUM>. The mesh routers <NUM> and the client device <NUM> may include additional functions and interfaces that are omitted from <FIG> for the sake of clarity.

The mesh router <NUM> includes antennas <NUM>, a radio frequency front end <NUM> (RF front end <NUM>), one or more transceivers <NUM> that are configured for WLAN (Wi-Fi) communication with the client device <NUM> and/or another mesh router. The RF front end <NUM> can couple or connect the transceivers <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> of the mesh router <NUM> may include an array of multiple antennas that are configured similarly to or differently from each other. The antennas <NUM> and the RF front end <NUM> can be tuned to, and/or be tunable to, one or more frequency bands defined by the IEEE <NUM> and/or Wi-Fi communication standards and implemented by the transceiver(s) <NUM>. Additionally, the antennas <NUM>, the RF front end <NUM>, and/or the transceiver(s) <NUM> may be configured to support beamforming for the transmission and reception of communications with the client device <NUM> and/or another mesh router.

The mesh router <NUM> also includes processor(s) <NUM> and computer-readable storage media <NUM> (CRM <NUM>). The processor <NUM> may be a single core processor or a multiple core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useful to store device data <NUM> of the mesh router <NUM>. The device data <NUM> includes network scheduling data, radio resource management data, applications, and/or an operating system of the mesh router <NUM>, which are executable by processor(s) <NUM> to enable communication with the client device <NUM> or for mesh link communications between the mesh routers <NUM>.

CRM <NUM> also includes an access point manager <NUM>, which, in one implementation, is embodied on CRM <NUM> (as shown). Alternately or additionally, the access point manager <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the mesh router <NUM>. In at least some aspects, the access point manager <NUM> configures the transceiver(s) <NUM> for communication with the client device <NUM> and/or another mesh router <NUM>, as well as communication of data over the Internet <NUM> via a network interface <NUM>. In at least some aspects, the access point manager <NUM> configures the RF front end <NUM> and the transceiver(s) <NUM> to implement the techniques for mesh network range extension and reliability enhancement through lower order MIMO spatial streams described herein.

The CRM <NUM> also includes a rate controller <NUM> and lookup table <NUM>, which, in one implementation, is embodied on CRM <NUM> (as shown). Alternately or additionally, the rate controller <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the mesh router <NUM>. The rate controller <NUM> uses a measurement of link quality and the lookup table <NUM> to determine a configuration for wireless communications. The rate controller <NUM> uses the measurement of link quality to perform a lookup in the lookup table <NUM> that includes Modulation and Coding Schemes (MCS) and channel bandwidths for the wireless communication. In one alternative, the lookup table <NUM> can be included in a Wi-Fi chipset that is included in the transceiver(s) <NUM>. Each MCS defines configuration parameters, such as a modulation type.

The client device <NUM> includes antennas <NUM>, a radio frequency front end <NUM> (RF front end <NUM>), one or more transceivers <NUM> for communicating with mesh routers <NUM> in the Wi-Fi network <NUM> (mesh network <NUM>). The RF front end <NUM> of the client device <NUM> can couple or connect the transceiver(s) <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> of the client device <NUM> may include an array of multiple antennas that are configured similar to or differently from each other. The antennas <NUM> and the RF front end <NUM> can be tuned to, and/or be tunable to, one or more frequency bands defined by the IEEE <NUM> and Wi-Fi communication standards and implemented by the transceiver(s) <NUM>. Additionally, the antennas <NUM>, the RF front end <NUM>, the transceiver(s) <NUM> may be configured to support beamforming for the transmission and reception of communications with the mesh routers <NUM>.

The client device <NUM> also includes processor(s) <NUM> and computer-readable storage media <NUM> (CRM <NUM>). The processor(s) <NUM> may be a single core processor or a multiple core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. The computer-readable storage media described herein excludes propagating signals. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the client device <NUM>. The device data <NUM> includes user data, multimedia data, beamforming codebooks, applications, and/or an operating system of the client device <NUM>, which are executable by processor(s) <NUM> to enable wireless communication, signaling, and user interaction with the mesh routers <NUM>.

CRM <NUM> also includes a client device manager <NUM>. Alternately or additionally, the client device manager <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the client device <NUM>. The client device manager <NUM> configures the transceiver(s) <NUM> to implement the functions of a WLAN station (STA).

11ax mesh networks have radio frequency (RF) link budgets, which limit the range of operation and RF link reliability as data throughput has been intentionally maximized through the full utilization of an NxN MIMO channel carrying N spatial streams for data traffic at middle and far distance ranges. Rate adaptation techniques that optimize around maximum data throughput may fall short of providing coverage, and thus connectivity, over a wider space.

In aspects, reducing the number of spatial streams, N, to a lower value (e.g., N-<NUM>, where N=<NUM> or N-<NUM>, where N=<NUM>) at middle and far distance ranges using an optimized rate control algorithm, preemptively trades off a lower maximum data throughput limit for a higher link budget. This higher link budget provides longer range and higher RF link reliability by using an NxN spatial diversity of MIMO RF channels for maximizing link budget instead of network throughput.

For example, the <NUM> bandwidth of <NUM>. 11ax (Wi-Fi 6E) can support adequate data throughput on mesh links (e.g., mesh links <NUM>, <NUM>, and <NUM>) and data links (e.g., wireless links <NUM> and <NUM>) with the reduced number of spatial streams of N-<NUM> (where N=<NUM>) or N-<NUM> (where N=<NUM>), while increasing the range and improving the reliability of the mesh network <NUM>.

Conventional rate adaptation techniques in many Wi-Fi access points, Wi-Fi mesh routers, and Wi-Fi chipsets measure a packet error rate (PER) for a communication link with a station (STA) device (e.g., the client device <NUM>) or another mesh router. These conventional techniques use the measured PER to perform a lookup in a three-dimensional lookup table of Modulation and Coding Schemes (MCS), a number of spatial streams (NSS), and channel bandwidths. Typically, these techniques will first alter the MCS (e.g., reducing the MCS as far down as MCS0) in an attempt to improve link quality (reducing the measured PER) with the STA (or other mesh router) before changing the NSS or the channel bandwidth to improve link quality.

In one aspect, a rate control controller (e.g., the rate controller <NUM>) of the Wi-Fi mesh router measures a Received Signal Strength Indicator (RSSI) or a Received Channel Power Indicator (RCPI) of received packet transmissions from a STA or another Wi-Fi mesh router. Based on the RSSI or RCPI, the rate controller selects a number of spatial streams (NSS) for the wireless link with the STA or other Wi-Fi mesh router and provides the value of the NSS to a Wi-Fi chipset. The Wi-Fi chipset uses that NSS value to perform a lookup in a two-dimensional lookup table of Modulation and Coding Scheme (MCS) and channel bandwidths. Alternatively, the rate controller <NUM> can perform the lookup in the lookup table <NUM> that is included in the CRM <NUM>. The resulting configuration of MCS and channel bandwidth along with the NSS value is used to configure the Wi-Fi transceivers for the wireless link between the Wi-Fi mesh router and the STA or other Wi-Fi mesh router.

In an alternative aspect, a rate control controller (e.g., the rate controller <NUM>) of the Wi-Fi mesh router uses a data throughput of the current communication with a STA or another Wi-Fi mesh router as an input to select a number of spatial streams (NSS) for the wireless link with the STA or other Wi-Fi mesh router and provides the value of the NSS to a Wi-Fi chipset. As in the previous aspect, the Wi-Fi chipset uses that NSS value to perform a lookup in a two-dimensional lookup table of Modulation and Coding Scheme (MCS) and channel bandwidth. Alternatively, the rate controller <NUM> can perform the lookup in the lookup table <NUM> that is included in the CRM <NUM>. The resulting configuration of MCS and channel bandwidth along with the NSS value is used to configure the Wi-Fi transceivers for the wireless link between the Wi-Fi mesh router and the STA or other Wi-Fi mesh router.

In a further aspect, a rate control controller (e.g., the rate controller <NUM>) of the Wi-Fi mesh router uses a current MCS in use for communication with a STA or another Wi-Fi mesh router as an input to select a number of spatial streams (NSS) for the wireless link with the STA or other Wi-Fi mesh router and provides the value of the NSS to a Wi-Fi chipset. As in the previous aspect, the Wi-Fi chipset uses that NSS value to perform a lookup in a two-dimensional lookup table of Modulation and Coding Scheme (MCS) and channel bandwidth. Alternatively, the rate controller <NUM> can perform the lookup in the lookup table <NUM> that is included in the CRM <NUM>. The resulting configuration of MCS and channel bandwidth along with the NSS value is used to configure the Wi-Fi transceivers for the wireless link between the Wi-Fi mesh router and the STA or other Wi-Fi mesh router.

<FIG> illustrates example data throughputs versus path loss for various combinations of a number of spatial streams and channel bandwidths in accordance with various aspects of mesh network range extension and reliability enhancement through lower order MIMO spatial streams. The dotted line NSS2-<NUM> in <FIG> illustrates the data throughput for a Wi-Fi mesh router using a conventional rate controller that maintains two spatial streams (NSS=<NUM>) in an <NUM> channel bandwidth.

In the aspects discussed above, the rate controller <NUM> selects switch points between the number of spatial streams and channel bandwidths based on an RSSI, an RCPI, data throughput, or a current MCS. In this example, the wireless mesh router operates in three regions <NUM>, <NUM>, and <NUM> that are selected by the rate controller <NUM> to optimize the Wi-Fi coverage area. Although three regions are shown, any suitable number of regions can be used. For example, at lower path loss values in region <NUM> (generally corresponding to a higher RSSI, a higher RCPI, a high data throughput, or a higher MCS), the rate controller <NUM> sends a value for NSS=<NUM> to the Wi-Fi chipset in the transceiver(s) <NUM> that the Wi-Fi chipset uses for a rate adaptation lookup to select a channel bandwidth of <NUM> (illustrated by the solid line NSS2-<NUM> in <FIG>) and an appropriate MCS (e.g., MCS0 to MCS13) to configure the transceiver(s) <NUM> for Wi-Fi communication with a STA or another Wi-Fi mesh router.

Continuing with the example, under conditions where path loss increases (generally corresponding to a medium RSSI, a medium RCPI, a medium data throughput, or a medium MCS), the rate controller <NUM> optimizes the Wi-Fi coverage area by selecting operation in region <NUM> with a value of NSS=<NUM>. The rate controller <NUM> sends a value for NSS=<NUM> to the Wi-Fi chipset in the transceiver(s) <NUM> that the Wi-Fi chipset uses for a rate adaptation lookup to select a channel bandwidth of <NUM> (illustrated by the short-dashed line NSS1-<NUM> in <FIG>) and an appropriate MCS to configure the transceiver(s) <NUM> for Wi-Fi communication with the STA or the other Wi-Fi mesh router.

Continuing further with the example, under conditions where path loss is largest (generally corresponding to a low RSSI, a low RCPI, a low data throughput, or a low MCS), the rate controller <NUM> optimizes the Wi-Fi coverage area by selecting operation in region <NUM> with a value of NSS=<NUM>. The rate controller <NUM> sends a value for NSS=<NUM> to the Wi-Fi chipset in the transceiver(s) <NUM> that the Wi-Fi chipset uses for a rate adaptation lookup to select a channel bandwidth of <NUM> (illustrated by the long-dashed line NSS1-<NUM> in <FIG>) and an appropriate MCS to configure the transceiver(s) <NUM> for Wi-Fi communication with the STA or the other Wi-Fi mesh router.

By selecting the appropriate switch points <NUM> and <NUM>, the rate controller <NUM> selects configuration of the number of spatial streams and channel bandwidth that increases Wi-Fi coverage while maintaining a high data throughput. Although this example is illustrated as using one or two spatial streams and two channel bandwidths, the described techniques are applicable to any suitable number of spatial streams (e.g., one to eight spatial streams) and any number of channel bandwidths of any suitable bandwidth (e.g., <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> channel bandwidths).

Example method <NUM> is described with reference to <FIG> in accordance with one or more aspects of mesh network range extension and reliability enhancement through lower order MIMO spatial streams. The order in which the method blocks are described are not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order, or skipped to implement a method or an alternate method. Generally, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), or any combination thereof. Some operations of the example methods may be described in the general context of executable instructions stored on computer-readable storage memory that is local and/or remote to a computer processing system, and implementations can include software applications, programs, functions, and the like. Alternatively or in addition, any of the functionality described herein can be performed, at least in part, by one or more hardware logic components, such as, and without limitation, Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SoCs), Complex Programmable Logic Devices (CPLDs), and the like.

<FIG> illustrates example method(s) <NUM> of mesh network range extension and reliability enhancement through lower order MIMO spatial streams as generally related to the wireless mesh router <NUM>. At block <NUM>, a wireless mesh router measures an indication of a link quality between the wireless mesh router and another wireless device. For example, the wireless mesh router (e.g., the wireless mesh router <NUM>, <NUM>, or <NUM>) measures a link quality (e.g., an RSSI, an RCPI, a data throughput, a PER, or an MCS).

At block <NUM>, the wireless mesh router determines (e.g., reduces) a number of spatial streams for the wireless communication based on the measured indication of link quality or a combination of the measured indications of link quality. For example, a rate controller (e.g., the rate controller <NUM>) in the wireless mesh router determines a number of spatial steams based on the measured indication of link quality. As an example, the rate controller of the wireless mesh router may compare the measured indication of link quality with at least one threshold value (and/or one or more regions of values) to determine the number of spatial streams.

At block <NUM>, using the determined number of spatial streams, the wireless mesh router selects a channel bandwidth and a Modulation and Coding Scheme (MCS) for the wireless communication. For example, the rate controller uses the determined number of spatial streams to lookup a channel bandwidth and an MCS in a lookup table (e.g., the lookup table <NUM>). For example, the lookup table may comprise two or more, e.g., all, of the following bandwidths: a <NUM> channel bandwidth, a <NUM> channel bandwidth, an <NUM> channel bandwidth, a <NUM> channel bandwidth, and a <NUM> channel bandwidth. Alternatively, or in addition, the lookup table may comprise two or more, e.g., all, of the following MCS: an MCS0 MCS: an MCS1 MCS, an MCS2 MCS, an MCS3 MCS, an MCS4 MCS, an MCS5 MCS, an MCS6 MCS, an MCS7 MCS, an MCS8 MCS, an MCS9 MCS, an MCS10 MCS, an MCS11 MCS, an MCS12 MCS and an MCS13 MCS.

At block <NUM>, the wireless mesh router configures a wireless transceiver for the wireless communication using the determined number of spatial streams, the selected channel bandwidth, and the selected MCS. For example, the rate controller <NUM> and/or the access point manager <NUM> configures a wireless transceiver (e.g., the transceiver <NUM>) for wireless communication using the determined number of spatial streams, the selected channel bandwidth, and the selected MCS.

Claim 1:
A method (<NUM>) to improve wireless communication range and reliability in a wireless mesh network (<NUM>) by a wireless mesh router (<NUM>-<NUM>), the method comprising:
measuring (<NUM>) a first indication of a link quality between the wireless mesh router (<NUM>-<NUM>) and a first wireless device (<NUM>-<NUM>, <NUM>);
determining (<NUM>) a number of spatial streams for the wireless communication based on the measured first indication of link quality;
using (<NUM>) the determined number of spatial streams to select a channel bandwidth and a Modulation and Coding Scheme, MCS, for the wireless communication; and
configuring (<NUM>) a wireless transceiver (<NUM>) for the wireless communication using the determined number of spatial streams, the selected channel bandwidth, and the selected MCS.