PARALLEL SCANNING OF WIRELESS CHANNELS
`
`Inventors:
`
`Gireesh Hegde
`Harish Vaidya
`Rakesh Raman
`Sriram Neelakandan
`
`BACKGROUND
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`Technical Field
`
`[0001]
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`The subject matter described herein generally relates to methods and apparatuses
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`for parallel scanning of channels in communication networks, such as a wireless local
`
`area network (WLAN).
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`Description of Related Art
`
`[0002]
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`Communication systems typically support wired and wireless communications
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`between communication devices. Communication systems operate in accordance with
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`one of more communication standards,
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`such as Ethernet or
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`IEEE 802.11/Wi-Fi.
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`Depending on the type of communication system, a wireless communication device, such
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`as a cellular telephone or laptop computer, may communicate directly or indirectly with
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`other wireless communication devices. For direct communication (i.e., point-to-point),
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`the participating wireless communication devices tune their transceivers to the same
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`channel(s) (e.g., one of a variety of channels in an operating frequency range of the
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`wireless communication system) and communicate over those channel(s). For indirect
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`communication, each wireless communication device communicates directly with an
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`associated access point via an assigned channel.
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`[0003]
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`Thus,
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`for indirect wireless communication, a wireless communication device
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`typically performs a scanning operation to discover access points that are available to
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`communicate with the wireless communication device. Conventionally, the scanning
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`operation includes sending a probe request and listening for probe request response(s)
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`from available access points in a sequential manner, scanning one channelat a time until
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`all channels have been scanned for a particular frequency band. The scanning operation
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`may continue with respect to another frequency bandif the wireless device is capable of
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`operating in that frequency band. The length of the scanning operation depends on the
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`number of channels and/or frequency bands that are to be scanned. The longer the
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`scanning operation, the more power is consumed. Many wireless communication devices
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`are mobile devices that are battery-powered. Thus, power conservation (e.g., powering
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`downtransceivers) is important, especially for wireless communication devices.
`
`BRIEF SUMMARY
`
`[0004]
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`Methods, systems, and apparatuses are described for parallel scanning of wireless
`
`channels in a communication network, substantially as shown in and/or described herein
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`in connection with at least one of the figures, as set forth more completely in the claims.
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`BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES
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`[0005]
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`The accompanying drawings, which are incorporated herein and form a part of the
`
`specification, illustrate the subject matter of the present application and, together with the
`
`description, further serve to explain the principles of the embodiments described herein
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`and to enable a person skilled in the pertinent art to make and use such embodiments.
`
`[0006]
`
`FIG.
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`1 is a block diagram of an example simultaneous dual-band communication
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`system in accordance with an embodiment.
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`[0007]
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`FIG.2 is a block diagram of an example parallel scanning device shownin FIG .1
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`in accordance with an embodiment.
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`[0008]
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`FIG. 3 depicts a flowchart of an example method for parallel scanning in
`
`accordance with an embodiment.
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`[0009]
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`FIG. 4 depicts a timing diagram of an example parallel scanning technique in
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`accordance with an embodiment.
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`[0010]
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`FIG. 5 is a block diagram of another example parallel scanning device in
`
`accordance with an embodiment.
`
`[0011]
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`FIG. 6 depicts a flowchart of an example method for scanning a plurality of
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`channels in a wireless network frequency band in accordance with an embodiment.
`
`[0012]
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`FIG. 7 is a block diagram of an example computing system that may be used to
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`implement various embodiments.
`
`[0013]
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`The subject matter of the present application will now be described with reference
`
`to the accompanying drawings. In the drawings, like reference numbersindicate identical
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`or functionally similar elements. Additionally,
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`the left-most digit(s) of a reference
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`numberidentifies the drawing in which the reference numberfirst appears.
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`DETAILED DESCRIPTION
`
`A.
`
`Introduction
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`[0014]
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`The following detailed description discloses numerous example embodiments.
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`The scope of the present patent application is not limited to the disclosed embodiments,
`
`but also encompasses combinations of
`
`the disclosed embodiments,
`
`as well
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`as
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`modifications to the disclosed embodiments.
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`[0015]
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`References in the specification to "one embodiment,” "an embodiment,” "an
`
`example embodiment,” etc.,
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`indicate that
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`the embodiment described may include a
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`particular feature, structure, or characteristic, but every embodiment may not necessarily
`
`include the particular feature, structure, or characteristic. Moreover, such phrases are not
`
`necessarily referring to the same embodiment. Furthermore, whena particular feature,
`
`structure, or characteristic is described in connection with an embodiment, it is submitted
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`that it is within the knowledgeof one skilled in the art to affect such feature, structure, or
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`characteristic in connection with other embodiments whetheror not explicitly described.
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`[0016]
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`Methods,
`
`systems,
`
`and apparatuses
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`for parallel
`
`scanning of channels
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`in
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`communication networks are described herein.
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`In accordance with certain embodiments,
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`a parallel scanning device performs a scanning operation that
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`includes parallel (i.e.,
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`simultaneous) scanning of channels that are in a common(i.e., same) frequency band or
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`different frequency bands. The parallel scanning of channels may result in a reduction of
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`scan time, which may reduce power consumption. For instance,
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`transceivers in the
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`parallel scanning device may be powered down or placed in an idle mode after the
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`scanning operation is completed. The power consumed during idle mode maybeless
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`than the power consumed during normal operating mode. Furthermore, the scanning
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`operation may undesirably interrupt and/or delay normal communication traffic to and
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`from the parallel scanning device, and a shorter scan time can reduce(e.g., eliminate) this
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`interruption and/or delay.
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`[0017]
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`Numerous exemplary embodiments are described as follows.
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`It is noted that any
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`section/subsection headings provided herein are not
`
`intended to be
`
`limiting.
`
`Embodiments are described throughout this document, and any type of embodiment may
`
`be included under any section/subsection. Furthermore, disclosed embodiments may be
`
`combined with each other in any manner.
`
`B.
`
`Example Embodiments
`
`[0018]
`
`FIG.
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`1 is a block diagram of an example simultaneous dual-band communication
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`system 100 in accordance with an embodiment. Communication system 100 supports
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`wireless and wired communications between wireless and/or wired devices, such as one
`
`or more access point(s) 102, a parallel scanning device 104, a camcorder 108, a camera
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`110, a printer 112, one or more speakers 114, a cellular phone 116, an external hard drive
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`118, and a monitor 120. Parallel scanning device 104 is a dual-radio/transceiver device
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`(e.g., station) that is capable of scanning WLAN channels,
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`in one or more frequency
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`bands, in parallel (i.e., scanning multiple (e.g., two) channels by simultaneously sending
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`probe requests via the multiple channels). Parallel scanning device 104 may be a wired or
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`wireless device. Each of the devices in communication system 100 may be directly or
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`indirectly connected to a communication network 106 via a wired or a wireless
`
`connection. Communication among the devices of communication system 100 is carried
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`out over communication network 106 using well-known network communication
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`protocols. Communication network 106 may be a wide-area network (e.g., the Internet),
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`a local area network (LAN) such as a wireless LAN (WLAN), a public switch telephone
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`network, another type of network, or a combination thereof.
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`In addition, access point(s)
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`102 may communicate with each other and/or other devices not shownin FIG. 1 directly
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`or indirectly via a system controller, the public switch telephone network, the Internet,
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`and/or via some other wide area network.
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`[0019]
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`Communication system 100 may operate in accordance with one or more wired
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`communication standards (e.g., Ethernet, System Packet Interface (SPI), or Secure Digital
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`Input Output (SDIO)), wireless communication standards(e.g., Institute of Electrical and
`
`Electronics Engineers
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`(IEEE) 802.11, Bluetooth, advanced mobile phone services
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`(AMPS), digital AMPS, global system for mobile communications (GSM), code division
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`multiple access (CDMA), time division synchronous code division multiple access (TD-
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`SCDMA),
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`local multi-point distribution systems (LMDS), or multi-channel-multiple-
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`point distribution systems (MMDS)), or various other standards.
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`[0020]
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`Forillustration purposes, embodiments may be described in connection with the
`
`TEEE 802.1 1/Wi-Fi standards, which implement WLAN communication in the 2.4, 3.6, 5,
`
`and 60 gigahertz (GHz) frequency bands. Although embodiments are described below
`
`with respect to the 2.4 and 5 GHz frequency bands, it will be recognized that the example
`
`embodiments are applicable to other suitable frequency bands.
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`Components that
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`communicate via a wireless medium in a WLANarereferred to as stations (STAs), which
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`are equipped with wireless network interface controllers. Stations may act as access
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`points or clients. An access point (e.g., a router) is a base station in a wireless network.
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`Such a base station transmits and receives radio signals to enable communication among
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`wireless clients. Wireless clients include but are not limited to mobile devices (e.g.,
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`laptops, personal digital assistants (PDAs), smartphones, and desktops/workstations that
`
`are equipped with a wireless network interface).
`
`[0021]
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`In order to participate in wireless communication, parallel scanning device 104
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`may perform a parallel scanning operation to find a suitable first access point (e.g., one of
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`access point(s) 102), and then authenticate and associate with the first access point. As
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`parallel scanning device 104 moves(e.g., out of range of the first access point), it may
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`authenticate a second access point (e.g., one of access point(s) 102 that is different from
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`the first access point). When association with the first access point is no longer desirable,
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`parallel scanning device 104 may associate with the second access point. The second
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`access point notifies the first access point of the new location of parallel scanning device
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`104 and terminates the previous association of parallel scanning device 104 with the first
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`access point. At somepoint, parallel scanning device 104 may need to perform another
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`scanning operation to find another access point and repeat
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`the authentication and
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`association process.
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`[0022]
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`FIG. 2 is a block diagram of an example parallel scanning device 200 configured
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`for parallel scanning in accordance with an example embodiment. Parallel scanning
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`device 200 may be an example of parallel scanning device 104 shown in FIG. 1. Parallel
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`scanning device 200 includes a scanner 202, a first transceiver 206, and a second
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`transceiver 210. First transceiver 206 and secondtransceiver 210 are shown in FIG. 2 as
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`being coupled to respective antennas 208 and 212 for illustrative purposes, thoughit will
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`be recognized that first transcetver 206 and second transceiver 210 may be coupled to a
`
`common(e.g., single) antenna.
`
`In some example embodiments, first antenna 208 and
`
`second antenna 212 are included in an antennaarray.
`
`[0023]
`
`In telecommunications, relatively low-frequency parts of a signal that is to be
`
`transmitted may be converted to relatively higher frequencies for transmission purposes
`
`because the relatively lower frequencies may be passed with greater distortion in some
`
`communication media. The original, relatively low-frequency components of the signal
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`are commonly referred to as the baseband signal and the converted, relatively high-
`
`frequency components are commonly referred to as the radio frequency (RF) signal. A
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`transceiver may bereferred to herein as a radio, a radio transceiver, and/or a transceiver
`
`chain as each transceiver operates under the medium access control (MAC) specification
`
`and the physical layer (PHY) specification.
`
`[0024]
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`Parallel scanning device 200 is operable in different modes. For example, parallel
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`scanning device 200 may be operated in a single-input single-output (SISO) mode, in
`
`which one transmitter and one receiver are utilized to send data over a single radio
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`frequency channel; multiple-input multiple-output mode,
`
`in which two or more
`
`transmitters and two or morereceivers are utilized to send data simultaneously over the
`
`same radio frequency channel, or real simultaneous dual-band (RSDB) mode, in which
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`multiple transceivers are utilized to send data simultaneously over the same or different
`
`radio frequency channels/bands. The input and output terminology refers to the radio
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`frequency channel.
`
`For example,
`
`the input
`
`(single or multiple)
`
`is driven by the
`
`transmitter(s) and the output (single or multiple) feeds the receiver(s).
`
`[0025]
`
`Scanner 202 is configured to conduct a scanning operation to discover access
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`points that are available to communicate with the parallel scanning device 200 via a
`
`wireless medium. Eachoffirst transceiver 206 and secondtransceiver 210 may include a
`
`data modulation stage and a radio frequency (RF) stage. The data modulation stage, in
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`the baseband process, converts between data and baseband signals in accordance with a
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`particular wireless communication standard (e.g., 802.11 standards).
`
`The RF stage
`
`includes transmitter circuitry and receiver circuitry, and converts between baseband
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`signals and RF signals. The RF stage may convert directly between baseband and RF or
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`may include one or more intermediate frequency stages. Eachoffirst transceiver 206 and
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`second transceiver 210 may be associated with an antenna configuration in accordance
`
`with an operating mode (e.g., SISO, MIMO, RSDB)thereof. An antenna configuration
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`indicates a relationship betweenfirst antenna 208 and second antenna 212 (e.g., same or
`
`different) and how they may be associated with first
`
`transceiver 206 and second
`
`transceiver 210. Each of scanner 202, first transceiver 206, and second transceiver 210
`
`may be implemented in hardware, or a combination of hardware and software and/or
`
`firmware. The operation ofparallel scanning device 200 will be described below.
`
`[0026]
`
`Scanner 202 is configured to perform a scanning operation on channels that are
`
`included in one or more frequency bands (e.g., 2.4 GHz or 5 GHz) to discover access
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`point(s) that are available to communicate with parallel scanning device 200.
`
`In
`
`accordance with the scanning operation, scanner 202 provides probe requests that are to
`
`be transmitted by first transceiver 206 and/or second transceiver 210 andlistens for probe
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`responses from available access points that are received by first transceiver 206 and/or
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`second transceiver 210. Scanner 202 includes scanning logic 204, which is configured to
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`provide a scan instruction indicating that multiple channels of a wireless network are to
`
`be scanned simultaneously. For example, scanning logic 204 is configured to provide a
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`scan instruction to first transceiver 206 and second transceiver 210, upon determining that
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`a scanning operation is to be performed,
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`instructing first transceiver 206 and second
`
`transceiver 210 to prepare for and conduct a parallel scan operation. The scanning
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`operation may include sending a frame to an access point with which the parallel
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`scanning device 200 is currently associated,
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`informing the access point that parallel
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`scanning device 200 is going into power-save mode.
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`In the power-save mode, parallel
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`scanning device 200 sends probe requests and may receive probe responsesin return.
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`[0027]
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`As part of the scanning operation, scanning logic 206 may determine which
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`channelto start scanning and/or which frequency band(s) to assign to first transceiver 206
`
`and/or second transceiver 210. For example, the 2.4 GHz frequency band covers the
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`frequency range of 2.4 to 2.4835 GHz and may include channels 1-14, for example. The
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`5 GHz frequency band covers the frequency range of 5.15 to 5.35 and 5.725 to 5.825 GHz
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`and includes far more channels than the 2.4 GHz frequency band.
`
`In either of these
`
`frequency bands,
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`the number of channels in each frequency band depends on the
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`geographic region (e.g., country) in which parallel scanning device 200 operates because
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`the usage of frequency bands typically is regulated by governmental entities.
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`For
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`example, in the United States, the 2.4 GHz frequency band includes 11 channels, and the
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`5 GHz frequency band includes 22 channels.
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`In Europe, the 2.4 GHz frequency band
`
`includes 13 channels, and the 5 GHz frequency band includes 24 channels.
`
`In Japan, the
`
`2.4 GHz frequency band includes 14 channels, and the 5 GHz frequency band includes 27
`
`channels.
`
`[0028]
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`Scanning logic 204 is further configured to determine an antenna configuration
`
`and/or to configure antennas that are available to first transceiver 206 and second
`
`transceiver 210 (e.g., antenna 208 and/or antenna 212). The antenna configuration may
`
`influence the scanning operation.
`
`In an example embodiment,first transceiver 206 and
`
`second transceiver 210 share a common(i.¢., same) antenna(e.g., antenna 208 or antenna
`
`212) and may simultaneously send a first probe request and a second probe request from
`
`the common antenna.
`
`In accordance with this embodiment, a parallel scan may be
`
`performed with respect to channels in different frequency bands or with respect to
`
`channels in a common frequency band so long as the channels that are simultaneously
`
`scanned are sufficiently separated so that the scanning of each channel does not unduly
`
`interfere with scanning of the other channel.
`
`In another example embodiment, each of
`
`first transceiver 206 and second transceiver 210 has a dedicated antenna. For instance, as
`
`shown in FIG. 2, first transceiver 206 may be coupledto first antenna 208, and second
`
`transceiver 210 may be coupled to second antenna 212.
`
`In accordance with this
`
`embodiment, scanning logic 204 may simultaneously provide a first probe request and a
`
`second probe request from the first antenna 208 and second antenna 212, respectively. In
`
`further accordance with this embodiment, a parallel scan may be performed with respect
`
`to channels in different frequency bands or with respect to channels in a common
`
`frequency band.
`
`[0029]
`
`If parallel scanning device 200 is currently associated with an access point,
`
`scanning logic 204 may send the associated access point a message (e.g.,
`
`frame)
`
`indicating that parallel scanning device 200 intends to go into power-save mode. During
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`power-save mode, normal
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`traffic between the associated access point and parallel
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`scanning device 200 may be temporarily suspended(e.g., the associated access point may
`
`hold (e.g., buffer) incoming data and hold outgoing data) until parallel scanning device
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`200 is no longer in power-save mode. Typically,
`
`in order to maintain the association
`
`between parallel scanning device 200 and the associated access point, parallel scanning
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`device 200 needs to be active on the channel of the associated access point (e.g., home
`
`channel) at predetermined times (e.g., according to beacon timing controlled by the
`
`associated access point) to receive a beacon from the associated access point. A beaconis
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`a frame that includes information such as timestamp, beacon interval, capability, service
`
`set identifier, supported rates, country, power constraint, channel switch announcement,
`
`antenna, high-throughput capabilities, and other parameters or information. When an
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`association needs to be maintained, the scanning operation may at times be suspended to
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`accommodate the receipt of the beacon on the home channel. Depending on the operating
`
`mode of parallel scanning device 200,
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`it may be possible for only one transceiver to
`
`utilize the home channel to await the beacon while the other transceiver may continue
`
`with the scanning process. When parallel scanning device 200 is not currently associated
`
`with an access point, the scanning operation may be performed through completion(i.e.,
`
`all channelsin all frequency bands have been scanned) without any suspension.
`
`[0030]
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`Scanning logic 204 is further configured to control the sending of probe requests
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`and receiving of probe responses from access points. Moreover,first transceiver 206 and
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`second transceiver 210 are configured to simultaneously provide respective first and
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`second probe requests via respective first and second channels in response to receipt of a
`
`scan instruction from scanning logic 204. The first probe request
`
`is configured to
`
`discover first access point(s) that are available to communicate with parallel scanning
`
`device 200 via the first channel. The second probe request is configured to discover
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`second access point(s) that are available to communicate with parallel scanning device
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`200 via the second channel. For example, a first probe request may be sent from first
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`transceiver 206 on a channel in the 2.4 GHz band, and a second probe request may be
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`sent from second transceiver 210 on a channel in the 5 GHz frequency band.
`
`In another
`
`example, a first probe request may be sent on a first channel in a frequency band(e.g., 2.4
`
`GHz or 5 GHz), and a second request may be sent on a second channel in the same
`
`frequency band.
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`[0031]
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`A probe request is a request (e.g., frame) that is configured to solicit a response
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`from each access point that is available to communicate with the parallel scanning device
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`(parallel scanning device 200) with which the probe request is transmitted. The probe
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`request may request information and/or contain information such as service set identifiers,
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`supported rates, extended supported rates, distribution system parameter set, supported
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`operating classes, high throughput capabilities, 20/40 basic service set coexistence,
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`extended capabilities, service set
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`identifier list, channel usage,
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`interworking, a mesh
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`identifier, and/or other information (e.g., vendor specific information).
`
`[0032]
`
`Scanning logic 204 is configured to monitor the channels that are being scanned
`
`by first transceiver 206 and second transceiver 210 for a designated period of time after
`
`the probe requests are sent to determine whether a response is received from one or more
`
`access points.
`
`The designated period of time (a.k.a dwell
`
`time) is a configurable
`
`parameter (e.g., 20 milliseconds). An access point that is available to communicate with
`
`parallel scanning device 200 via the scanned channel may respond to the probe request
`
`with a probe response(e.g., frame). The probe response may contain information such as
`
`timestamp, beacon interval, capability, service set identifier, supported rates, frequency
`
`hopping parameter set, distributed service set parameter set, contention-free parameter
`
`set,
`
`independent basic service set, country, frequency hopping parameters, frequency
`
`hopping pattern table, power constraint, channel
`
`switch announcement, extended
`
`supported rates, robust security network, basic service set load, beacon timing, and/or
`
`other information. The scanning operation may continue with the sending of probe
`
`requests and receiving of probe responses via each of the channels in sequential order
`
`(e.g., channel 1 is scanned before channel2).
`
`[0033]
`
`There may be more channels to scan in the 5 GHz frequency band than in the 2.4
`
`GHz frequency band. Thus, in one example embodiment, after all channels in the 2.4
`
`GHz frequency band have been scanned during a parallel scanning process, both first
`
`transceiver 206 and second transceiver 210 may be used to scan the remaining channels in
`
`the 5 GHz frequency band.
`
`In accordance with this example embodiment, the parallel
`
`scanning process involves simultaneously sending probe requests to different channels in
`
`the same frequency band(i.e., the 5 GHz frequency band in this example). While there
`
`may be nointerference problems whenfirst transceiver 206 and second transceiver 210
`
`simultaneously operate in different frequency bands, there may be some interference
`
`issues with first transceiver 206 and second transceiver 210 operating in the same
`
`frequency band. For example, there may be channel interference issues if two probe
`
`requests are sent to two channels that are adjacent to each other. Thus, scanning logic
`
`204 may be configured to determine the separation needed between the channels to be
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`scanned to avoid interference issues. This determination may be based on the antenna
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`configuration and/or specific characteristics of the frequency bands(e.g., channel width
`
`and/or spacing between the channels).
`
`[0034]
`
`Scanning logic 204 is further configured to provide scan results to an application.
`
`Such application may be a software-based application on a smartphone or other mobile
`
`parallel scanning devices. The scan results may indicate access points that are available
`
`to communicate with parallel scanning device 200 via the scanned channels of one or
`
`more frequency bands.
`
`In particular, the scan results may indicate each access point that
`
`is available to connect with the parallel scanning device 200 via each scanned channel.
`
`The scan results may include information (e.g., addresses, capabilities, and beacon times)
`
`compiled from probe responses received from available access points.
`
`[0035]
`
`In embodiments, parallel scanning device 200 may operate in various ways to
`
`perform a parallel scanning operation. For instance, FIG. 3 depicts a flowchart 300 of an
`
`example method for parallel scanning in accordance with an embodiment. Flowchart 300
`
`is described with respect to parallel scanning device 200 and communication system 100
`
`for illustrative purposes. The steps of flowchart 300 may be performed in an order
`
`different than the order shown in FIG. 3 in some embodiments. Further structural and
`
`operational embodiments will be apparent to persons skilled in the relevant art(s) based
`
`on the following description of flowchart 300.
`
`[0036]
`
`Flowchart 300 beings with step 302.
`
`In step 302, a scan instruction indicating that
`
`a plurality of channels of a wireless network are to be scanned. For example,
`
`in an
`
`embodiment, scanning logic 204 is configured to provide the scan instruction indicating
`
`that the plurality of channels (e.g., channels of the 2.4 GHz and/or 5 GHz frequency
`
`bands) of the wireless network (e.g., communication network 106) are to be scanned. The
`
`scan instruction may be generated by scanning logic 204 or derived from a scan request
`
`from an application (e.g., a software application running on a smartphone), a user
`
`command, or some other source.
`
`The scan instruction may be provided to first
`
`transceiver 206 and secondtransceiver 210 in the scanning process.
`
`[0037]
`
`Flowchart 300 continues with step 304.
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`In step 304, a scanning operation is
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`initiated with regard to the plurality of channels in response to receiving the scan
`
`instruction. The scanning operation includes simultaneously providing a first probe
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`request via a first channel of the plurality of channels fromafirst transceiver of a parallel
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`scanning device and a second probe request via a second channel of the plurality of
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`BP32109 / A05.02070000
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`—~12-
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`channels from a second transceiver of the parallel scanning device in response to
`
`receiving the scan instruction. The first probe request is configured to discover one or
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`morefirst access points that are available to connect with the parallel scanning device via
`
`the first channel. The second probe request is configured to discover one or more second
`
`access points that are available to connect with the parallel scanning device via the second
`
`channel.
`
`[0038]
`
`For example, in an embodiment, scanning logic 204 is configured to initiate a
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`scanning operation as described above in connection with parallel scanning device 200.
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`The scanning operation may include simultaneously providing a first probe request via a
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`first channel of the plurality of channels (e.g., channels on either the 2.4 GHz or the 5
`
`GHz frequency band) from first transceiver 206 of parallel scanning device 200 and a
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`second probe request via a second channel of the plurality of channels from second
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`transceiver 210 of parallel scanning device 200 in response to receiving the scan
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`instruction from scanning logic 204. Thefirst probe request is configured to discover one
`
`or morefirst access points that are available to connect with parallel scanning device 200
`
`via the first channel. Moreover, the second probe request is configured to discover one or
`
`more second access points that are available to connect with parallel scanning device 200
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`via the second channel.
`
`[0039]
`
`In an embodiment,first transceiver 206 and secondtransceiver 210 are configured
`
`to simultaneously provide the first probe request via the first channel in a first wireless
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`local area network frequency band (e.g., 2.4 GHz frequency band or 5GHz frequency
`
`band) and the second probe request via the second channel in a second wireless local area
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`network frequency band that
`
`is different from the first wireless local area network
`
`frequency band.
`
`In another embodiment, first transceiver 206 and secondtransceiver 210
`
`are configured to simultaneously provide the first and second probe requests via
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`respective first and second channels of the same wireless local area network frequency
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`band (e.g., either 2.4 GHz or 5 GHz).
`
`In yet another example embodiment,
`
`first
`
`transceiver 206 and second transceiver 210 are configured to simultaneously send the
`
`respective first and second probe requests from a single, shared antenna.
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`In a further
`
`embodiment,
`
`first
`
`transceiver 206 and second transceiver 210 are configured to
`
`simultaneously provide the respective first and second probe requests from respective
`
`first and second antennas.
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`BP32109 / A05.02070000
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`—~13-
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`[0040]
`
`In an example embodiment, scanning logic 204 is configured to monitorthe first
`
`channel during a designated period oftime (e.g., dwell time) to determine whether at least
`
`one first response is received from at least one respective first access point via the first
`
`channel in response to the first probe request.
`
`In accordance with this embodiment,
`
`scanning logic 204 is further configured to monitor the second channel during the
`
`designated period of time to determine whether at least one second response is received
`
`from at least one respective second access point via the second channel in response to the
`
`second probe request. The dwell time is configurable (e.g., 30 milliseconds) and may be
`
`configured manually or automatically by a user of the parallel scanning device 200, by a
`
`software program/routine, or some otherentity.
`
`[0041]
`
`In an example embodiment, scanning logic 204 is configured to provide scan
`
`results regarding the scanning operation to an application (e.g., an application on a mobile
`
`device). The scan results may indicate access points that are available to communicate
`
`with parallel scanning device 200 via the plurality of channels of the wireless network
`
`(e.g., channels on the 2.4 GHz frequency band and/or the 5 GHz frequency band).
`
`In
`
`particular, the scan results may indicate each first access point from whicha first response
`
`is received and each second access point from which a second response is received. The
`
`scan results may include information (e.g., addresses, capabilities, and/or beacon times)
`
`gathered from probe responses received from the available access points.
`
`[0042]
`
`FIG. 4 depicts a timing diagram of a parallel scanning technique in accordance
`
`with an embodiment. FIG.4 is described in connection with communication system 100
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`and/or parallel scanning device 200 for illustration purposes, and is not intended to be
`
`limiting. Timing intervals 402 correspondtoafirst frequency band (2.4 GHzin this non-
`
`limiting example), and timing intervals 404 correspond to a second frequency band (5.0
`
`GHz in this non-limiting example).
`
`“A” represents a first
`
`transceiver (