Patent Publication Number: US-2022240166-A1

Title: Methods and systems for network discovery using a fast parallel active scan

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application claims the benefit of and priority to Indian Provisional Application No. 202121003868, filed on Jan. 28, 2021, which is hereby incorporated by reference herein in its entirety. 
     FIELD OF THE DISCLOSURE 
     This disclosure generally relates to systems and methods for scanning operations in communication systems. In particular, this disclosure relates to systems and methods for discovering wireless networks by active scanning. 
     BACKGROUND OF THE DISCLOSURE 
     In the last few decades, the market for wireless communications devices has grown by orders of magnitude, fueled by the need for portable devices, and increased connectivity and data transfer between all manners of devices. Digital switching techniques have facilitated the large scale deployment of affordable, easy-to-use wireless communication networks. Furthermore, digital and radio frequency (RF) circuit fabrication improvements, as well as advances in circuit integration and other aspects have made wireless equipment smaller, cheaper, and more reliable. Wireless communication may operate in accordance with various standards such as IEEE 802.11x, IEEE 802.11ad, IEEE 802.11ac, IEEE 802.11n, IEEE 802.11ah, IEEE 802.11aj, IEEE 802.16 and 802.16a, Bluetooth, global system for mobile communications (GSM), code division multiple access (CDMA), and cellular technologies. As higher data throughput and other needs develop, newer standards are constantly being developed for adoption. Standards can provide protocols for discovering and accessing networks. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various objects, aspects, features, and advantages of the disclosure will become more apparent and better understood by referring to the detailed description taken in conjunction with the accompanying drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. 
         FIG. 1A  is a block diagram depicting an embodiment of a network environment including one or more access points in communication with one or more wireless devices or stations; 
         FIGS. 1B and 1C  are block diagrams depicting embodiments of computing devices useful in connection with the methods and systems described herein; 
         FIG. 2  is a block diagram of a communication system configured to use a scan technique for access to or discovery of a network according to some embodiments; 
         FIG. 3A  is a timing diagram illustrating the scan technique for the communication system illustrated in  FIG. 2  according to some embodiments; 
         FIG. 3B  is a timing diagram illustrating the scan technique for the communication system illustrated in  FIG. 2  according to some embodiments; and 
         FIG. 4  is a flow diagram illustrating another embodiment of a scanning operation for the communication system illustrated in  FIG. 2  according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The following IEEE standard(s), including any draft versions of such standard(s), are hereby incorporated herein by reference in their entirety and are made part of the present disclosure for all purposes IEEE 802.11x, IEEE 802.11ad, IEEE 802.11ah, IEEE 802.11aj, IEEE 802.16 and 802.16a, and IEEE 802.11ac. Although this disclosure may reference aspects of these standard(s), the disclosure is in no way limited by these standard(s). 
     For purposes of reading the description of the various embodiments below, the following descriptions of the sections of the specification and their respective contents may be helpful. Section A describes a network environment and computing environment which may be useful for practicing embodiments described herein, and Section B describes embodiments of systems and methods of scanning for a wireless network. Some embodiments of the systems and methods can utilize a scanning technique for wireless network discovery that uses two or more radios. The scanning technique is a fast parallel active scan (FPAS) to access a WiFi network or other wireless network in some embodiments. The scanning technique can advantageously perform an active scan on two parallel channels by using a fast channel switch mechanism, a main radio or main core, and a scan radio or a scan core. 
     Some embodiments relate to a method of scanning for wireless networks using a wireless integrated package including a first radio and a second radio. The method includes providing a first probe request in a first time slot on a first channel using the first radio, and receiving a first probe response in a second time slot on the first channel using the second radio. The second time slot is at least partially contemporaneous with the first time slot. 
     Some embodiments relate to a wireless device. The wireless device comprises a processor. The processor is configured to provide a first probe request in a first time slot on a first channel using the first radio. The processor is configured to await reception of (e.g., listen for) a first probe response in a second time slot on the first channel using the second radio, wherein the second time slot is at least partially contemporaneous with the first time slot. 
     Some embodiments relate to a method of wireless communication. The method includes providing a first probe request from a first wireless device including a first transceiver circuit and a receiver circuit in single integrated circuit package. The method first probe request is in a first time slot on a first channel using the first transceiver circuit. The method also includes receiving a first probe response in a second time slot on the first channel using the receiver circuit. The second time slot is at least partially contemporaneous with the first time slot or at least partially overlaps the first time slot. 
     A. Computing and Network Environment 
     Prior to discussing specific embodiments of the present solution, it may be helpful to describe aspects of the operating environment as well as associated system components (e.g., hardware elements) in connection with the methods and systems described herein. Referring to  FIG. 1A , an embodiment of a network environment is depicted. In brief overview, the network environment includes a wireless communication system that includes one or more access points  106 , one or more wireless communication devices  102  and a network hardware component  192 . The wireless communication devices  102  may for example include laptop computers  102 , tablets  102 , personal computers  102 , wearable devices  102 , vehicles  102  (e.g., automobiles, drones, smart vehicles, robotic units, etc.) and/or cellular telephone devices  102 . The details of an embodiment of wireless communication devices  102  and/or access point  106  are described in greater detail with reference to  FIGS. 1B and 1C . The network environment can be an ad hoc network environment, an infrastructure wireless network environment, a subnet environment, etc. in one embodiment 
     The access points (APs)  106  may be operably coupled to the network hardware  192  via local area network connections. The network hardware  192 , which may include a router, gateway, switch, bridge, modem, system controller, appliance, etc., may provide a local area network connection for the communication system. Each of the access points  106  may have an associated antenna or an antenna array to communicate with the wireless communication devices in its area. The wireless communication devices may register with a particular access point  106  to receive services from the communication system (e.g., via a SU-MIMO or MU-MIMO configuration). For direct connections (i.e., point-to-point communications), some wireless communication devices may communicate directly via an allocated channel and communications protocol. Some of the wireless communication devices  102  may be mobile or relatively static with respect to the access point  106 . 
     In some embodiments an access point  106  includes a device or module (including a combination of hardware and software) that allows wireless communication devices  102  to connect to a wired network using Wi-Fi, or other standards. An access point  106  may sometimes be referred to as a wireless access point (WAP). An access point  106  may be configured, designed and/or built for operating in a wireless local area network (WLAN). An access point  106  may connect to a router (e.g., via a wired network) as a standalone device in some embodiments. In other embodiments, an access point  106  can be a component of a router. An access point  106  can provide multiple devices access to a network. An access point  106  may, for example, connect to a wired Ethernet connection and provides wireless connections using radio frequency links for other devices  102  to utilize that wired connection. An access point  106  may be built and/or configured to support a standard for sending and receiving data using one or more radio frequencies. Those standards, and the frequencies they use may be defined by the IEEE (e.g., IEEE 802.11 standards). An access point  106  may be configured and/or used to support public Internet hotspots, and/or on an internal network to extend the network&#39;s Wi-Fi signal range. 
     In some embodiments, the access points  106  may be used for in-home or in-building wireless networks (e.g., IEEE 802.11, Bluetooth, ZigBee, any other type of radio frequency based network protocol and/or variations thereof). Each of the wireless communication devices  102  may include a built-in radio and/or is coupled to a radio. Such wireless communication devices  102  and/or access points  106  may operate in accordance with the various aspects of the disclosure as presented herein to enhance performance, reduce costs and/or size, and/or enhance broadband applications. Each wireless communication devices  102  may have the capacity to function as a client node seeking access to resources (e.g., data, and connection to networked nodes such as servers) via one or more access points. 
     The network connections may include any type and/or form of network and may include any of the following: a point-to-point network, a broadcast network, a telecommunications network, a data communication network, a computer network. The topology of the network may be a bus, star, or ring network topology. The network may be of any such network topology as known to those ordinarily skilled in the art capable of supporting the operations described herein. In some embodiments, different types of data may be transmitted via different protocols. In other embodiments, the same types of data may be transmitted via different protocols. 
     The communications device(s)  102  and access point(s)  106  may be deployed as and/or executed on any type and form of computing device, such as a computer, network device or appliance capable of communicating on any type and form of network and performing the operations described herein.  FIGS. 1B and 1C  depict block diagrams of a computing device  100  useful for practicing an embodiment of the wireless communication device  102  or access point  106 . As shown in  FIGS. 1B and 1C , each computing device  100  includes a central processing unit  121 , and a main memory unit  122 . As shown in  FIG. 1B , a computing device  100  may include a storage device  128 , an installation device  116 , a network interface  118 , an I/O controller  123 , display devices  124   a - 101   n , a keyboard  126  and a pointing device  127 , such as a mouse. The storage device  128  may include, without limitation, an operating system and/or software. As shown in  FIG. 1C , each computing device  100  may also include additional optional elements, such as a memory port  103 , a bridge  170 , one or more input/output devices  130   a - 130   n  (generally referred to using reference numeral  130 ), and a cache memory  140  in communication with the central processing unit  121 . 
     The central processing unit  121  is any logic circuitry that responds to and processes instructions fetched from the main memory unit  122 . In many embodiments, the central processing unit  121  is provided by a microprocessor unit, such as: those manufactured by Intel Corporation of Mountain View, Calif.; those manufactured by International Business Machines of White Plains, N.Y.; or those manufactured by Advanced Micro Devices of Sunnyvale, Calif. The computing device  100  may be based on any of these processors, or any other processor capable of operating as described herein. 
     Main memory unit  122  may be one or more memory chips capable of storing data and allowing any storage location to be directly accessed by the microprocessor  121 , such as any type or variant of Static random access memory (SRAM), Dynamic random access memory (DRAM), Ferroelectric RAM (FRAM), NAND Flash, NOR Flash and Solid State Drives (SSD). The main memory  122  may be based on any of the above described memory chips, or any other available memory chips capable of operating as described herein. In the embodiment shown in  FIG. 1B , the processor  121  communicates with main memory  122  via a system bus  150  (described in more detail below).  FIG. 1C  depicts an embodiment of a computing device  100  in which the processor communicates directly with main memory  122  via a memory port  103 . For example, in  FIG. 1C  the main memory  122  may be DRDRAM. 
       FIG. 1C  depicts an embodiment in which the main processor  121  communicates directly with cache memory  140  via a secondary bus, sometimes referred to as a backside bus. In other embodiments, the main processor  121  communicates with cache memory  140  using the system bus  150 . Cache memory  140  typically has a faster response time than main memory  122  and is provided by, for example, SRAM, BSRAM, or EDRAM. In the embodiment shown in  FIG. 1C , the processor  121  communicates with various I/O devices  130  via a local system bus  150 . Various buses may be used to connect the central processing unit  121  to any of the I/O devices  130 , for example, a VESA VL bus, an ISA bus, an EISA bus, a MicroChannel Architecture (MCA) bus, a PCI bus, a PCI-X bus, a PCI-Express bus, or a NuBus. For embodiments in which the I/O device is a video display  124 , the processor  121  may use an Advanced Graphics Port (AGP) to communicate with the display  124 .  FIG. 1C  depicts an embodiment of a computer  100  in which the main processor  121  may communicate directly with I/O device  130   b , for example via HYPERTRANSPORT, RAPIDIO, or INFINIBAND communications technology.  FIG. 1C  also depicts an embodiment in which local busses and direct communication are mixed: the processor  121  communicates with I/O device  130   a  using a local interconnect bus while communicating with I/O device  130   b  directly. 
     A wide variety of I/O devices  130   a - 130   n  may be present in the computing device  100 . Input devices include keyboards, mice, trackpads, trackballs, microphones, dials, touch pads, touch screen, and drawing tablets. Output devices include video displays, speakers, inkjet printers, laser printers, projectors and dye-sublimation printers. The I/O devices may be controlled by an I/O controller  123  as shown in  FIG. 1B . The I/O controller may control one or more I/O devices such as a keyboard  126  and a pointing device  127 , e.g., a mouse or optical pen. Furthermore, an I/O device may also provide storage and/or an installation medium  116  for the computing device  100 . In still other embodiments, the computing device  100  may provide USB connections (not shown) to receive handheld USB storage devices such as the USB Flash Drive line of devices manufactured by Twintech Industry, Inc. of Los Alamitos, Calif. 
     Referring again to  FIG. 1B , the computing device  100  may support any suitable installation device  116 , such as a disk drive, a CD-ROM drive, a CD-R/RW drive, a DVD-ROM drive, a flash memory drive, tape drives of various formats, USB device, hard-drive, a network interface, or any other device suitable for installing software and programs. The computing device  100  may further include a storage device, such as one or more hard disk drives or redundant arrays of independent disks, for storing an operating system and other related software, and for storing application software programs such as any program or software  120  for implementing (e.g., software  120  configured and/or designed for) the systems and methods described herein. Optionally, any of the installation devices  116  could also be used as the storage device. Additionally, the operating system and the software can be run from a bootable medium. 
     Furthermore, the computing device  100  may include a network interface  118  to interface to the network  104  through a variety of connections including, but not limited to, standard telephone lines, LAN or WAN links (e.g., 802.11, T1, T3, 56 kb, X.25, SNA, DECNET), broadband connections (e.g., ISDN, Frame Relay, ATM, Gigabit Ethernet, Ethernet-over-SONET), wireless connections, or some combination of any or all of the above. Connections can be established using a variety of communication protocols (e.g., TCP/IP, IPX, SPX, NetBIOS, Ethernet, ARCNET, SONET, SDH, Fiber Distributed Data Interface (FDDI), RS232, IEEE 802.11, IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, IEEE 802.11ac, IEEE 802.11ad, CDMA, GSM, WiMax and direct asynchronous connections). In one embodiment, the computing device  100  communicates with other computing devices  100 ′ via any type and/or form of gateway or tunneling protocol such as Secure Socket Layer (SSL) or Transport Layer Security (TLS). The network interface  118  may include a built-in network adapter, network interface card, PCMCIA network card, card bus network adapter, wireless network adapter, USB network adapter, modem or any other device suitable for interfacing the computing device  100  to any type of network capable of communication and performing the operations described herein. 
     In some embodiments, the computing device  100  may include or be connected to one or more display devices  124   a - 124   n . As such, any of the I/O devices  130   a - 130   n  and/or the I/O controller  123  may include any type and/or form of suitable hardware, software, or combination of hardware and software to support, enable or provide for the connection and use of the display device(s)  124   a - 124   n  by the computing device  100 . For example, the computing device  100  may include any type and/or form of video adapter, video card, driver, and/or library to interface, communicate, connect or otherwise use the display device(s)  124   a - 124   n . In one embodiment, a video adapter may include multiple connectors to interface to the display device(s)  124   a - 124   n . In other embodiments, the computing device  100  may include multiple video adapters, with each video adapter connected to the display device(s)  124   a - 124   n . In some embodiments, any portion of the operating system of the computing device  100  may be configured for using multiple displays  124   a - 124   n . One ordinarily skilled in the art will recognize and appreciate the various ways and embodiments that a computing device  100  may be configured to have one or more display devices  124   a - 124   n.    
     In further embodiments, an I/O device  130  may be a bridge between the system bus  150  and an external communication bus, such as a USB bus, an Apple Desktop Bus, an RS-232 serial connection, a SCSI bus, a FireWire bus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, a Gigabit Ethernet bus, an Asynchronous Transfer Mode bus, a FibreChannel bus, a Serial Attached small computer system interface bus, a USB connection, or a HDMI bus. 
     A computing device  100  of the sort depicted in  FIGS. 1B and 1C  may operate under the control of an operating system, which control scheduling of tasks and access to system resources. The computing device  100  can be running any operating system such as any of the versions of the MICROSOFT WINDOWS operating systems, the different releases of the Unix and Linux operating systems, any version of the MAC OS for Macintosh computers, any embedded operating system, any real-time operating system, any open source operating system, any proprietary operating system, any operating systems for mobile computing devices, or any other operating system capable of running on the computing device and performing the operations described herein. Typical operating systems include, but are not limited to: Android, produced by Google Inc.; WINDOWS 7 and 8, produced by Microsoft Corporation of Redmond, Wash.; MAC OS, produced by Apple Computer of Cupertino, Calif.; WebOS, produced by Research In Motion (RIM); OS/2, produced by International Business Machines of Armonk, N.Y.; and Linux, a freely-available operating system distributed by Caldera Corp. of Salt Lake City, Utah, or any type and/or form of a Unix operating system, among others. 
     The computer system  100  can be any workstation, telephone, desktop computer, laptop or notebook computer, server, handheld computer, mobile telephone or other portable telecommunications device, media playing device, a gaming system, mobile computing device, or any other type and/or form of computing, telecommunications or media device that is capable of communication. The computer system  100  has sufficient processor power and memory capacity to perform the operations described herein. 
     In some embodiments, the computing device  100  may have different processors, operating systems, and input devices consistent with the device. For example, in one embodiment, the computing device  100  is a smart phone, mobile device, tablet or personal digital assistant. In still other embodiments, the computing device  100  is an Android-based mobile device, an iPhone smart phone manufactured by Apple Computer of Cupertino, Calif., or a Blackberry or WebOS-based handheld device or smart phone, such as the devices manufactured by Research In Motion Limited. Moreover, the computing device  100  can be any workstation, desktop computer, laptop or notebook computer, server, handheld computer, mobile telephone, any other computer, or other form of computing or telecommunications device that is capable of communication and that has sufficient processor power and memory capacity to perform the operations described herein. 
     Aspects of the operating environments and components described above will become apparent in the context of the systems and methods disclosed herein. 
     B. Systems and Methods of Scanning for a Wireless Network 
     Described herein with reference to  FIGS. 2-4 , systems and methods are used by wireless devices  102  to scan actively for one or more wireless networks, such as wireless network  101  in some embodiments. The wireless device  102  can be one of the devices shown in  FIGS. 1A-C . The wireless network  101  generally includes one or more access points such as access point  106  for wireless connectivity to wireless devices  102 . In some embodiments, wireless device  102  includes a main radio  202  with an antenna  203 , a scan radio  204  with an antenna  205 , and a processor  200 . Antennas  203  and  205  are antenna arrays, and the wireless device  102  is capable of beam forming in some embodiments. 
     The wireless device  102  actively broadcasts a probe request signal or the like in accordance with an active scanning technique in some embodiments. The probe request signal solicits a probe response signal from available access points, such as the access point  106 . The wireless device  102  uses the probe response signal to gain access to the network  101 . The interchange of the probe request and probe response signals is generally referred to as a “handshake.” Conventionally, such scanning process can be time consuming. Embodiments of the system and methods described herein can reduce the time required for scanning by using the main radio  202  and the scan radio  204  at least partially simultaneously. 
     In some embodiments, the probe request signal provides an 802.11 frame requesting information from either a specific access point, specified by SSID, or all access points in the area, specified with the broadcast SSID. The frame can be a management frame seeking available networks on a channel. The probe request signal can be provided on each channel or a subset of channels in a sequence in some embodiments. In some embodiments, the information being requested by the probe request signal includes the supported data rates which are also included in the beacon frames broadcast from the access point  106 . 
     In some embodiments, the access point  106  sends out a probe response signal in response to the probe request frame which was either directed to a specific access point or to all stations in the area using the broadcast SSID. Similar to a beacon frame, the probe response signal contains a frame including information required for the wireless device  102  and the access point  106  to begin communicating and/or requested by the probe request signal. The wireless device  102  can send an acknowledgement of the received probe response signal. 
     In some embodiments, the main radio  202 , scan radio  204 , and processor  200  are disposed on a single substrate  210  or in a single integrated circuit package. The package can be a multi-chip module. In some embodiments, main radio  202  and a scan radio  204  are disposed on a single substrate  210  or in a single integrated circuit package, and processor  200  is a separate integrated circuit. In some embodiments, processing functions are performed in the radios  202  and  204 , and the processor  200  is a supervisory processor. 
     The processor  200  is implemented as a communications controller and can include memory, logic arrays, programmable gate arrays, groups of processing components, interfaces, isolation components, and filter components, analog and digital support circuits or other suitable electronic processing components in some embodiments. In some embodiments, the memory is one or more storage devices (e.g., RAM, ROM) for storing data and computer code for completing and facilitating the processes, layers, and modules described herein. The memory may be or include volatile memory or non-volatile memory. 
     The processor  200  is in communication with main radio  202  and scan radio  204 . The processor  200  includes circuitry for controlling the radios  202  and  204 , processing signals received from the radios  202  and  204 , and processing signals for transmission by the radios  202  and  204 . In some embodiments, the processor  200  is configured to control the radios  202  and  204  to provide the scanning operations described herein. The radios  202  and  204  provide wireless communication operations for the wireless device  102 . The main radio  202  and the scan radio  204  each include radio frequency components for independently communicating wirelessly with one or more wireless networks such as wireless network  101 . Main radio  202  and scan radio  204  can share certain components in some embodiments. 
     The radios  202  and  204  are physical layer devices in some embodiments. The radios  202  and  204  include frequency synthesizers, channel selection circuits, digital to analog converter, analog to digital converter, amplifiers, mixers, modulators, demodulators, encoders, decoders, interface, isolation, and filter components, analog and digital support circuits, beam forming circuits, or other suitable electronic processing components in some embodiments. In some embodiments, each of the radios  202  and  204  includes its own transceiver. In some embodiments, the scan radio  204  is a receive only radio. 
     The wireless network  101  can be any type of wireless network. For example, wireless network  101  can be a IEEE 802.11x, IEEE 802.11ad, IEEE 802.11ac, IEEE 802.11n, IEEE 802.11ah, IEEE 802.11aj, IEEE 802.16 and 802.16a, Bluetooth, global system for mobile communications (GSM), code division multiple access (CDMA), long term evolution (LTE), or a 5G network. The wireless network  101  can be a permanent network, a temporary, or an ad hoc network. 
     Referring to  FIGS. 2 and 3A , the wireless device  102  performs a fast parallel active scan operation to discover and join wireless networks such as wireless network  101 . The wireless device  102  transmits a probe request on a first channel (e.g., channel  36 ) at a time t on an X-axis  300  using the main radio  202 . The X-axis  300  represents time. The transmission of the transmit probe request occurs in a time slot  252 . In some embodiments, the time slot  252  is a predetermined length of time (e.g., 0.5 milliseconds, 0.25 milliseconds, 1 milliseconds, etc.). At time t or just after time t, the wireless device  102  listens for or awaits for reception of a probe request response in a time slot  262  on the first channel (e.g., channel  36 ) using the scan radio  204 . Time for the scan radio  204  is represented on an X-axis  260 . The time slot  262  is a fixed time slot that is the same length as the time slot  252  (e.g., approximately 0.5 milliseconds) in some embodiments. The time slot  262  at least partially overlaps or is at least partially contemporaneous with the time slot  252  (e.g., for approximately 0.5 milliseconds) in some embodiments. 
     After time slot  252  and  262  expire, a channel switch operation occurs in the main radio  202  and the scan radio  204  in a time slot  254 . The channel switch operation occurs in 0.016 milliseconds or less in some embodiments. The channel switch operation can involve adjusting the frequency synthesizer of the main radio  202  to provide an appropriate frequency for the new channel. The channel switch operation causes the main radio  202  and the scan radio  204  to operate using a second channel (e.g., channel  48 ). After the time slot  254 , the wireless device  102  transmits another probe request on the second channel (e.g., channel  48 ) using the main radio  202 . The time slot  256  is a fixed period (e.g., 5 milliseconds) in some embodiments. After the time slot  262 , the wireless device  103  listens for or awaits for reception of a probe request response in a time slot  264  on the second channel (e.g., channel  48 ) using the scan radio  204 . The time slot  264  at least partially overlaps or is at least partially contemporaneous with the time slot  256  (e.g., for approximately 0.5 milliseconds) in some embodiments. Time slot  264  is a fixed period (e.g., 0.5 milliseconds) in some embodiments. Time slot  264  has the same length as time slot  256  in some embodiments. In some embodiments, the time slots  252 ,  254 ,  262 , and  264  are not fixed and are set based upon configuration parameters or network settings. 
     Processor  200  controls the main radio  202  and scan radio  204  to achieve fast parallel active scan operations in some embodiments. Fast parallel active scan operations save time by transmitting the probe request on a another channel without needing to wait a full dwell time on each channel to receive a probe response and by switching the channel to transmit the next probe request in the next channel in some embodiments. The scanning sequence can be repeated until all channels are scanned. In some embodiments, the fast parallel active scan operations reduce the active scan duration by more than 40 percent or approximately 50 percent. In some embodiments, the fast parallel active scan operations are used for 2 Gigahertz (GHz) and/or 5 GHz scans. In some embodiments, 6 GHZ scans can be utilized. The first channel and the second channel are WiFi channels in some embodiments. 
     Referring to  FIGS. 2 and 3B , the wireless device  102  performs a fast parallel active scan operation to discover and join wireless networks such as wireless network  101  similar to the operation discussed with reference to  FIG. 3A . The wireless device  102  transmits a probe request on a first channel (e.g., channel  36 ) at a time t on an X-axis  300  using the main radio  202 . The X-axis  300  represents time. The transmission of the transmit probe request occurs in a time slot  302 . In some embodiments, the time slot  302  is a predetermined length of time (e.g., 0.5 milliseconds, 0.25 milliseconds, 1 milliseconds, etc.). At time t or just after time t, the wireless device  102  listens for or awaits for reception of a probe request response in a time slot  312  on the first channel (e.g., channel  36 ) using the scan radio  204 . Time for the scan radio  204  is represented on an X-axis  310 . The time slot  312  is a fixed time slot that is longer than the time slot  302  (e.g., approximately 21 milliseconds) in some embodiments. The time slot  312  at least partially overlaps or is at least partially contemporaneous with the time slot  302  (e.g., for approximately 0.5 milliseconds) in some embodiments. 
     After time slot  302  expires, a channel switch operation occurs in the main radio  202  in a time slot  304 . The channel switch operation occurs in 0.016 milliseconds or less in some embodiments. The channel switch operation causes the main radio  202  to operate using a second channel (e.g., channel  48 ). In some embodiments, the scan radio  204  remains at the first channel. At a time slot  306  after the time slot  304 , the wireless device  102  transmits another probe request on the second channel (e.g., channel  48 ) using the main radio  202 . Time slot  306  is a fixed period (e.g., 0.5 milliseconds) in some embodiments. After the time slot  306 , the wireless device  102  listens for or awaits for reception of a probe request response in a time slot  308  on the second channel (e.g., channel  48 ) using the main radio  202 . The time slot  312  at least partially overlaps or is at least partially contemporaneous with each of the time slots  304 ,  306  and  308  in some embodiments. The time slot  308  is a fixed period (e.g., 20 milliseconds) in some embodiments. The time slot  306  is a fixed period (e.g., 0.5 milliseconds) in some embodiments. In some embodiments, the time slots  302 ,  304 ,  308 , and  312  are not fixed and are set based upon configuration parameters or network settings. In some embodiments, the first channel is in a lower frequency band (e.g., 2 GHz) and the second channel is on a higher frequency band (e.g., 5 GHz). In some embodiments, the scan radio  204  is operational in the lower frequency band only or is operational over a smaller bandwidth than the main radio  202 . 
     Referring to  FIGS. 2, 3A -B, and  4 , a flow  400  can be performed by wireless device  102  to discover a wireless network, such as the wireless network  101 , according to some embodiments. At an operation  402 , the wireless device  102  transmits a probe request on a first channel using the main radio  202 . At an operation  402 , the wireless device  102  listens for a response to the probe request on a first channel using the scan radio  204 . At an operation  406 , the wireless device  102  switches channels to a second channel. 
     At an operation  408 , the wireless device  102  transmits another probe request on a second channel using the main radio  202 . At an operation  412 , the wireless device  102  listens for a response to the probe request on the second channel using the scan radio  204 . In some embodiments, at the operation  412 , the wireless device  102  listens for a response to the probe request on the second channel using the main radio  202  while the scan radio  204  listens for the probe request on the first channel in operation  404 . At an operation  414 , the wireless device  102  switches channels to a third channel. At an operation  416 , flow  400  is repeated until all channels are scanned. Channels can include 2 GHz channels of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 and 5 GHZ channels of 36, 40, 44, 48, 144, 149, 153, 157, 161, and 165 in some embodiments. 
     Although the disclosure may reference one or more “users”, such “users” may refer to user-associated devices, for example, consistent with the terms “user” and “multi-user” typically used in the context of a multi-user multiple-input and multiple-output (MU-MIMO) environment. Although examples of communications systems described above may include wireless devices and access points operating according to an 802.11 standard, it should be understood that embodiments of the systems and methods described can operate according to other standards and use wireless communications devices other than devices discussed herein. For example, multiple user communications capable interfaces associated with cellular networks, satellite communications, vehicle communication networks, and other non-802.11 wireless networks can utilize the systems and methods described herein to achieve improved scanning without departing from the scope of the systems and methods described herein. 
     It should be noted that certain passages of this disclosure may reference terms such as “first” and “second” in connection with devices, number of bits, transmission durations, etc., for purposes of identifying or differentiating one from another or from others. These terms are not intended to merely relate entities (e.g., a first device and a second device) temporally or according to a sequence, although in some cases, these entities may include such a relationship. Nor do these terms limit the number of possible entities (e.g., devices) that may operate within a system or environment. 
     It should be understood that the systems described above may provide multiple ones of any or each of those components and these components may be provided on either a standalone machine or, in some embodiments, on multiple machines in a distributed system. In addition, the systems and methods described above may be provided as one or more computer-readable programs or executable instructions embodied on or in one or more articles of manufacture. The article of manufacture may be a floppy disk, a hard disk, a CD-ROM, a flash memory card, a PROM, a RAM, a ROM, or a magnetic tape. In general, the computer-readable programs may be implemented in any programming language, such as LISP, PERL, C, C++, C#, PROLOG, or in any byte code language such as JAVA. The software programs or executable instructions may be stored on or in one or more articles of manufacture as object code. 
     While the foregoing written description of the methods and systems enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The present methods and systems should therefore not be limited by the above described embodiments, methods, and examples, but by all embodiments and methods within the scope and spirit of the disclosure.