Wi-Fi mesh network routers suffer from limited range and reliability issues due to link budget limitations when an N×M Multiple-Input, Multiple-Output (MIMO) channel is fully utilized to carry N spatial data streams in order to maximize network data throughput. Maximizing throughput has an impact on the range covered by a Wi-Fi mesh network router. However, there are opportunities to change rate adaptation techniques to provide more consistent Wi-Fi coverage for the user.
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 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 and communicates with the other wireless device using the configured wireless transceiver.
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:
Overview
Wi-Fi mesh network routers suffer from limited range and reliability issues due to link budget limitations when an N×N 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 802.11ax mesh routers with Wi-Fi 6 backhaul where transmit power is significantly reduced by the regulatory requirements for Low Power Indoor (LPI) 802.11ax 6E devices. The LPI transmit power reduction when using a Modulation and Coding Scheme 0 (MCS0) varies from 4.5 dB to 7.5 dB, depending on the channel bandwidth (e.g., 160 MHz or 80 MHz 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 802.11ax mesh routers with Wi-Fi 6 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=3 or N=4) adds hardware cost to a mesh router and affects the form factor of the product design as compared to using two antennas (N=2). 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.
Example Environment
The mesh routers 110 are connected by wired (e.g., Ethernet) or wireless backhaul links (mesh links) at 151, 152, and 153 to send network traffic between client devices 130 and/or between client devices and the Internet 180 and remote service(s) 190. For example, one or more mesh routers, such as the mesh router 111 include a network interface to connect to the Internet 180, such as via a cable modem or DSL modem.
Example Devices
The mesh router 110 includes antennas 202, a radio frequency front end 204 (RF front end 204), one or more transceivers 206 that are configured for WLAN (Wi-Fi) communication with the client device 130. The RF front end 204 can couple or connect the transceivers 206 to the antennas 202 to facilitate various types of wireless communication. The antennas 202 of the mesh router 110 may include an array of multiple antennas that are configured similarly to or differently from each other. The antennas 202 and the RF front end 204 can be tuned to, and/or be tunable to, one or more frequency bands defined by the IEEE 802.11 and/or Wi-Fi communication standards and implemented by the transceiver(s) 206. Additionally, the antennas 202, the RF front end 204, and/or the transceiver(s) 206 may be configured to support beamforming for the transmission and reception of communications with the client device 130.
The mesh router 110 also includes processor(s) 208 and computer-readable storage media 210 (CRM 210). The processor 208 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 210 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 212 of the mesh router 110. The device data 212 includes network scheduling data, radio resource management data, applications, and/or an operating system of the mesh router 110, which are executable by processor(s) 208 to enable communication with the client device 130 or for mesh link communications between the mesh routers 110.
CRM 210 also includes an access point manager 214, which, in one implementation, is embodied on CRM 210 (as shown). Alternately or additionally, the access point manager 214 may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the mesh router 110. In at least some aspects, the access point manager 214 configures the transceiver(s) 206 for communication with the client device 130, as well as communication of data over the Internet 180 via a network interface 220. In at least some aspects, the access point manager 214 configures the RF front end 202 and the transceiver(s) 206 to implement the techniques for mesh network range extension and reliability enhancement through lower order MIMO spatial streams described herein.
The CRM 210 also includes a rate controller 216 and lookup table 218, which, in one implementation, is embodied on CRM 210 (as shown). Alternately or additionally, the rate controller 216 may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the mesh router 110. The rate controller 216 uses a measurement of link quality and the lookup table 218 to determine a configuration for wireless communications. The rate controller 216 uses the measurement of link quality to perform a lookup in the lookup table 218 that includes Modulation and Coding Scheme (MCS) and channel bandwidths for the wireless communication. In one alternative, the lookup table 218 can be included in a Wi-Fi chipset that is included in the transceiver(s) 206.
The client device 130 includes antennas 252, a radio frequency front end 254 (RF front end 254), one or more transceivers 256 for communicating with mesh routers 110 in the Wi-Fi network 120 (mesh network 120). The RF front end 254 of the client device 130 can couple or connect the transceiver(s) 256 to the antennas 252 to facilitate various types of wireless communication. The antennas 252 of the client device 130 may include an array of multiple antennas that are configured similar to or differently from each other. The antennas 252 and the RF front end 254 can be tuned to, and/or be tunable to, one or more frequency bands defined by the IEEE 802.11 and Wi-Fi communication standards and implemented by the transceiver(s) 256. Additionally, the antennas 252, the RF front end 254, the transceiver(s) 256 may be configured to support beamforming for the transmission and reception of communications with the mesh routers 110.
The client device 130 also includes processor(s) 258 and computer-readable storage media 260 (CRM 260). The processor(s) 258 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 260 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 262 of the client device 130. The device data 262 includes user data, multimedia data, beamforming codebooks, applications, and/or an operating system of the client device 130, which are executable by processor(s) 258 to enable wireless communication, signaling, and user interaction with the mesh routers 110.
CRM 260 also includes a client device manager 264. Alternately or additionally, the client device manager 264 may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the client device 130. The client device manager 264 configures the transceiver(s) 256 to implement the functions of a WLAN station (STA).
Rate Adaptation to Improve Mesh Network Range Extension and Reliability
802.11ax 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 N×N 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−1, where N=2 or N−2, where N=3) 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 N×N spatial diversity of MIMO RF channels for maximizing link budget instead of network throughput.
For example, the 160 MHz bandwidth of 801.11ax (Wi-Fi 6E) can support adequate data throughput on mesh links (e.g., mesh links 151, 152, and 153) and data links (e.g., wireless links 141 and 142) with the reduced number of spatial streams of N−1 (where N=2) or N−2 (where N=3), while increasing the range and improving the reliability of the mesh network 120.
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 130) 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 216) 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 216 can perform the lookup in the lookup table 218 that is included in the CRM 210. 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 216) 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 216 can perform the lookup in the lookup table 218 that is included in the CRM 210. 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 further aspect, a rate control controller (e.g., the rate controller 216) 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 216 can perform the lookup in the lookup table 218 that is included in the CRM 210. 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 the aspects discussed above, the rate controller 216 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 302, 304, and 306 that are selected by the rate controller 216 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 302 (generally corresponding to a higher RSSI, a higher RCPI, a high data throughput, or a higher MCS), the rate controller 216 sends a value for NSS=2 to the Wi-Fi chipset in the transceiver(s) 206 that the Wi-Fi chipset uses for a rate adaptation lookup to select a channel bandwidth of 160 MHz (illustrated by the solid line NSS2-160 in
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 216 optimizes the Wi-Fi coverage area by selecting operation in region 304 with a value of NSS=1. The rate controller 216 sends a value for NSS=1 to the Wi-Fi chipset in the transceiver(s) 206 that the Wi-Fi chipset uses for a rate adaptation lookup to select a channel bandwidth of 160 MHz (illustrated by the short-dashed line NSS1-160 in
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 216 optimizes the Wi-Fi coverage area by selecting operation in region 306 with a value of NSS=1. The rate controller 216 sends a value for NSS=1 to the Wi-Fi chipset in the transceiver(s) 206 that the Wi-Fi chipset uses for a rate adaptation lookup to select a channel bandwidth of 80 MHz (illustrated by the long-dashed line NSS1-80 in
By selecting the appropriate switch points 308 and 310, the rate controller 216 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., 20 MHz, 40 MHz, 80 MHz, 160 MHz, and/or 320 MHz channel bandwidths).
Example Method
Example method 400 is described with reference to
At block 404, the wireless mesh router determines 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 216) in the wireless mesh router determines a number of spatial steams based on the measured indication of link quality.
At block 406, using the determined number of spatial streams, the wireless mesh router selects a channel bandwidth and a Modulation and Coding Scheme (MC S) 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 218).
At block 408, 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 216 and/or the access point manager 214 configures a wireless transceiver (e.g., the transceiver 206) for wireless communication using the determined number of spatial streams, the selected channel bandwidth, and the selected MCS.
Although aspects of mesh network range extension and reliability enhancement through lower order MIMO spatial streams have been described in language specific to features and/or methods, the subject of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as example implementations of mesh network range extension and reliability enhancement through lower order MIMO spatial streams, and other equivalent features and methods are intended to be within the scope of the appended claims. Further, various different aspects are described, and it is to be appreciated that each described aspect can be implemented independently or in connection with one or more other described aspects.
Filing Document | Filing Date | Country | Kind |
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PCT/US2022/070528 | 2/4/2022 | WO |
Number | Date | Country | |
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63149059 | Feb 2021 | US |