Patent Publication Number: US-2018054739-A1

Title: Systems and methods for wireless transmission during channel availability check on mixed dfs channels

Description:
BACKGROUND 
     Field 
     The present application relates generally to wireless communications, and more specifically to systems, methods, and devices for wireless transmission during Channel Availability Check (CAC) on mixed Dynamic Frequency Selection (DFS) channels. 
     Background 
     In many telecommunication systems, communications networks are used to exchange messages among several interacting spatially-separated devices. Networks may be classified according to geographic scope, which could be, for example, a metropolitan area, a local area, or a personal area. Such networks would be designated respectively as a wide area network (WAN), metropolitan area network (MAN), local area network (LAN), wireless local area network (WLAN), or personal area network (PAN). 
     Wireless networks are often preferred when the network elements are mobile and thus have dynamic connectivity needs, or if the network architecture is formed in an ad hoc, rather than fixed, topology. Wireless networks employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infra-red, optical, etc. frequency bands. Wireless networks advantageously facilitate user mobility and rapid field deployment when compared to fixed wired networks. 
     The prevalence of multiple wireless networks may cause interference, reduced throughput (for example, because each wireless network is operating in the same area and/or spectrum), and/or prevent certain devices from communicating. Under certain conditions, communication over wireless networks may be prohibited and/or temporarily suspended due to government regulations, further preventing devices from communicating. Thus, improved systems, methods, and devices for communicating when wireless networks are densely populated, have interference, and/or are hindered by government regulations are desired. 
     SUMMARY 
     The systems, methods, and devices of the invention each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this invention as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this invention provide advantages that include improved communications between access points and stations in a wireless network. 
     One aspect of the present application provides a method of wireless communication. The method comprises identifying, at a first device, a plurality of subchannels of a transmission channel for transmission, the identified plurality of subchannels including one or more restricted subchannels and including one or more unrestricted subchannels. The method further comprises determining, at the first device, a first bandwidth configuration for the identified restricted subchannels and a second bandwidth configuration for the identified unrestricted subchannels. The method further comprises scanning, at the first device, for one or more restricted signals over one or more of the identified restricted subchannels. The method further comprises transmitting, at the first device, a beacon to a second device within a duration of the scanning, the beacon being transmitted over one or more of the identified unrestricted subchannels. 
     Another aspect of the present application provides an apparatus for wireless communication over a transmission channel. The apparatus comprises a signal detector. The apparatus further comprises a processor. The processor is configured to identify a plurality of subchannels of the transmission channel for transmission, the identified plurality of subchannels including one or more restricted subchannels and including one or more unrestricted subchannels. The processor is further configured to determine a first bandwidth configuration for the identified restricted subchannels and a second bandwidth configuration for the identified unrestricted subchannels. The processor is further configured to scan, by the signal detector, for one or more restricted signals over one or more of the identified restricted subchannels. The apparatus further comprises a transmitter. The transmitter is configured to transmit a beacon to a wireless device within a duration of the scan, the beacon being transmitted over one or more of the identified unrestricted sub channels. 
     Yet another aspect of the present application provides an apparatus for wireless communication. The apparatus comprises means for detecting signals. The apparatus further comprises means for identifying, at a first device, a plurality of subchannels of a transmission channel for transmission, the identified plurality of subchannels including one or more restricted subchannels and including one or more unrestricted subchannels, the means for identifying further determining, at the first device, a first bandwidth configuration for the identified restricted subchannels and a second bandwidth configuration for the identified unrestricted subchannels, and the means for identifying further scanning, by the means for detecting signals, for one or more restricted signals over one or more of the identified restricted subchannels. The apparatus further comprises means for transmitting, at the first device, a beacon to a second device within a duration of the scanning, the beacon being transmitted over one or more of the identified unrestricted sub channels. 
     Yet another aspect of the present application provides a non-transitory computer-readable medium comprising code that, when executed, causes an apparatus to perform a method, the method comprising identifying, at a first device, a plurality of subchannels of a transmission channel for transmission, the identified plurality of subchannels including one or more restricted subchannels and including one or more unrestricted subchannels. The method further comprises determining, at the first device, a first bandwidth configuration for the identified restricted subchannels and a second bandwidth configuration for the identified unrestricted subchannels. The method further comprises scanning, by the first device, for one or more restricted signals over one or more of the identified restricted subchannels. The method further comprises transmitting, at the first device, a beacon to a second device within a duration of the scanning, the beacon being transmitted over one or more of the identified unrestricted subchannels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a wireless communication system in which aspects of the present disclosure can be employed. 
         FIG. 2  is a functional block diagram of a wireless device that can be employed within the wireless communication systems disclosed herein. 
         FIG. 3  is a flowchart of a legacy method for wireless communication. 
         FIG. 4  is a time sequence diagram of a portion of the legacy method for wireless communication described with respect to  FIG. 3 . 
         FIG. 5  is a flowchart of a method for wireless communication, in accordance with an implementation. 
         FIG. 6  is a time sequence diagram of a portion of the method for wireless communication described with respect to  FIG. 5 . 
         FIG. 7  is a flowchart of a method for wireless communication, in accordance with an implementation. 
         FIG. 8  is a flowchart of a method for wireless communication, in accordance with an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various aspects of the novel systems, apparatuses, and methods are described more fully hereinafter with reference to the accompanying drawings. The teachings disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the novel systems, apparatuses, and methods disclosed herein, whether implemented independently of or combined with any other aspect of the invention. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the invention is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the invention set forth herein. It should be understood that any aspect disclosed herein may be embodied by one or more elements of a claim. 
     Although particular aspects are described herein, many variations and permutations of these aspects fall within the scope of the disclosure. Although some benefits and advantages of the preferred aspects are mentioned, the scope of the disclosure is not intended to be limited to particular benefits, uses, or objectives. Rather, aspects of the disclosure are intended to be broadly applicable to different wireless technologies, system configurations, networks, and transmission protocols, some of which are illustrated by way of example in the figures and in the following description of the preferred aspects. The detailed description and drawings are merely illustrative of the disclosure rather than limiting, the scope of the disclosure being defined by the appended claims and equivalents thereof 
     Wireless network technologies may include various types of wireless local area networks (WLANs). A WLAN may be used to interconnect nearby devices together, employing widely used networking protocols. The various aspects described herein may apply to any communication standard, such as Wi-Fi or, more generally, any member of the IEEE 802.11 family of wireless protocols. 
     In some aspects, wireless signals may be transmitted according to a high-efficiency 802.11 protocol using orthogonal frequency-division multiplexing (OFDM), direct-sequence spread spectrum (DSSS) communications, a combination of OFDM and DSSS communications, or other schemes. Implementations of the high-efficiency 802.11 protocol may be used for Internet access, sensors, metering, smart grid networks, or other wireless applications. Advantageously, aspects of certain devices implementing this particular wireless protocol may consume less power than devices implementing other wireless protocols, may be used to transmit wireless signals across short distances, and/or may be able to transmit signals less likely to be blocked by objects, such as humans. 
     In some implementations, a WLAN includes various devices which are the components that access the wireless network. For example, there may be two types of devices: access points (“AP”) and clients (also referred to as stations, or “STA”). In general, an AP serves as a hub or base station for the WLAN and a STA serves as a user of the WLAN. For example, a STA may be a laptop computer, a personal digital assistant (PDA), a mobile phone, etc. In an example, an STA connects to an AP via a Wi-Fi (e.g., IEEE 802.11 protocol such as 802.11ah) compliant wireless link to obtain general connectivity to the Internet or to other wide area networks. In some implementations an STA may also be used as an AP. 
     The techniques described herein may be used for various broadband wireless communication systems, including communication systems that are based on an orthogonal multiplexing scheme. Examples of such communication systems include Spatial Division Multiple Access (SDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency-Division Multiple Access (OFDMA) systems, Single-Carrier 
     Frequency-Division Multiple Access (SC-FDMA) systems, and so forth. An SDMA system may utilize sufficiently different directions to concurrently transmit data belonging to multiple user terminals. A TDMA system may allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time slots, each time slot being assigned to different user terminal. A TDMA system may implement GSM or some other standards known in the art. An OFDMA system utilizes orthogonal frequency-division multiplexing (OFDM), which is a modulation technique that partitions the overall system bandwidth into multiple orthogonal sub-carriers. These sub-carriers may also be called tones, bins, etc. With OFDM, each sub-carrier may be independently modulated with data. An OFDM system may implement IEEE 802.11 or some other standards known in the art. An SC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit on sub-carriers that are distributed across the system bandwidth, localized FDMA (LFDMA) to transmit on a block of adjacent sub-carriers, or enhanced FDMA (EFDMA) to transmit on multiple blocks of adjacent sub-carriers. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDMA. A SC-FDMA system may implement 3GPP-LTE (3rd Generation Partnership Project Long Term Evolution) or other standards. 
     The teachings herein may be incorporated into (e.g., implemented within or performed by) a variety of wired or wireless apparatuses (e.g., nodes). In some aspects, a wireless node implemented in accordance with the teachings herein may comprise an access point or an access terminal. 
     An access point (“AP”) may comprise, be implemented as, or known as a NodeB, Radio Network Controller (“RNC”), eNodeB, Base Station Controller (“BSC”), Base Transceiver Station (“BTS”), Base Station (“BS”), Transceiver Function (“TF”), Radio Router, Radio Transceiver, Basic Service Set (“BSS”), Extended Service Set (“ESS”), Radio Base Station (“RBS”), or some other terminology. 
     A station (“STA”) may also comprise, be implemented as, or known as a user terminal (“UT”), an access terminal (“AT”), a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user agent, a user device, user equipment, or some other terminology. In some implementations an access terminal may comprise a cellular telephone, a cordless telephone, a Session Initiation Protocol (“SIP”) phone, a wireless local loop (“WLL”) station, a personal digital assistant (“PDA”), a handheld device having wireless connection capability, or some other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a portable communication device, a headset, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a gaming device or system, a global positioning system device, or any other suitable device that is configured to communicate via a wireless medium. 
     Wireless devices utilize wireless networks to communicate with other wireless devices and to increase connectivity, flexibility, and speed. Many wireless devices connect to wireless networks according to a 802.11 protocol (for example, 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ah, etc.). Furthermore, wireless devices can connect to wireless networks at different frequencies (also known as “bandwidths”). Two commonly used frequencies include 2.4 GHz and 5 GHz. 
     As the capabilities of modern wireless devices have increased, the operating limitations of the 2.4 GHz bandwidth have caused an increase in demand for connecting modern wireless devices to the more capable 5 GHz bandwidth. Furthermore, some wireless technology protocols utilize the 5 GHz spectrum exclusively (e.g., 802.11 AC). 
     Governments also utilize the 5 GHz spectrum, for example, with respect to the transmission of radar signals (historically referred to as “RADAR”). Such utilizations can be related to military, aircraft, and/or weather-based communications, among other usages. Certain government regulations restrict certain wireless communications over at least portions of the 5 GHz spectrum. For example, non-government devices may be prohibited from using portions of a 5 GHz network when radar signals are present. Furthermore, more stringent regulations exist in the presence of certain variations of radar (e.g., in the presence of weather radar). 
     The nature of wireless technologies allows for many users to share the range of frequencies. A range of bandwidths or frequencies may be referred to individually or collectively as a “spectrum” or “spectrums,” e.g., 5.250 GHz to 5.350 GHz. Certain ranges of bandwidths or frequencies may be subdivided into channels of varying widths. For example, common channel widths related to the 5 GHz spectrum include 20 MHz, 40 MHz, 80 MHz, and 160 MHz. Modern wireless devices can transmit over multiple channels (or subchannels) at once to increase communication quality and/or to communicate with multiple other devices at the same time. For example, a wireless access point could operate at a 20 MHz bandwidth over eight channels at once, utilizing a total of 160 MHz of bandwidth to communicate with eight different other wireless devices (e.g., laptops). Similarly, such a wireless access point could operate over four 40 MHz channels at the same time, utilizing the same total of 160 MHz of bandwidth. 
     To that end, a wireless device can utilize channel identification (e.g., selection) procedures to identify and connect to a number of different channels. Wireless devices may perform channel identification based on various network or device specifications, while other wireless devices may perform channel identification in a random nature. For example, a wireless device performing a 5 GHz-based channel identification (e.g., a 802.11ac-based wireless access point at boot up) could identify eight 20 MHz subchannels of a 160 MHz channel (e.g., in accordance with a multiple-in-multiple-out (MIMO) communication). In this example, the eight 20 MHz subchannels may also be referred to as “HT20 subchannels,” where HT refers to high throughput. Similarly, a full 160 MHz channel (e.g., the 36 VHT 160 channel) can be referred to as a “VHT 160 channel,” where VHT refers to very high throughput. To the extent a wireless device capable of communicating at 160 MHz of bandwidth (e.g., a 802.11 AC-based access point) fails to connect to, or is delayed in the connection to, the entirety of a 160 MHz bandwidth, the full capability of the wireless device may not be achieved. For example, if such a wireless device were communicating over only four 20 MHz subchannels, or over only a single 80 MHz subchannel, 80 MHz of potential bandwidth usage would be going unused. 
     Furthermore, when wireless devices utilize the entirety of a 160 MHz bandwidth, based on the present bandwidth configuration of the wireless device, the wireless device can be said to be operating at a single, contiguous 160 MHz bandwidth or at one of many non-contiguous bandwidth variations thereof, e.g., at an “80+80 MHz” bandwidth or a “40+40+40+40 MHz” bandwidth, etc. When the wireless device sends connection advertisements (e.g., beacons, which may typically be sent every 100 ms) to potential connecting devices (e.g., a “STA,” a “user,” etc.), the wireless device will typically include an indication of such a bandwidth configuration in the beacon, among other information. In this way, for example, the STA receiving the beacon may determine if the wireless device is connectable and is capable of providing sufficient bandwidth for the STA. For example, certain wireless devices may only be capable of communicating over channels of up to 20 MHz (e.g., 802.11a/b/g devices) or of up to 40 MHz (e.g., 802.11n devices). Certain other wireless devices may be capable of communicating over channels of up to 80 MHz and/or 160 MHz (e.g., 802.11ah devices). 
     When utilizing the entirety of the 160 MHz bandwidth, a wireless device may be communicating at a contiguous 160 MHz or at a noncontiguous 80+80 MHz, depending on the configuration initiated by the wireless device. Data throughput may be the same in either configuration. Such configurations may also be referred to as bandwidth configurations, modes, bandwidth modes, etc. The wireless device may switch from operating in a 160 MHz mode or in a 80+80 MHz mode to operating in a single 80 MHz mode or in a 40+40 MHz mode, for example. In either such change, the maximum bandwidth throughput that the wireless device may be capable of decreases from 160 MHz to 80 MHz. Such a decrease in bandwidth utilization may be referred to as a bandwidth “step down” or “contraction.” For example, the wireless device may be forced to initiate a bandwidth step down in the event that previously available channels have become unavailable or prohibited from communication. In contrast, the wireless device may switch from operating in, for example, a single 80 MHz mode or in a 40+40 MHz mode to operating in a 160 MHz mode or in a 80+80 MHz mode. In these cases, the maximum bandwidth throughput that the wireless device may be capable of increases from 80 MHz to 160 MHz. Such an increase in bandwidth utilization may be referred to as a bandwidth “step up” or “expansion.” For example, the wireless device may initiate a bandwidth step up if previously unavailable or prohibited channels become available for communication. In accordance with an embodiment, when implementing bandwidth step ups or step downs, the wireless device may notify another device or devices (e.g., a STA or STAs) of the change. In one embodiment, the wireless device may notify other devices of the change in a beacon, for example a beacon that includes a Bandwidth Switch Announcement (BSA), as further discussed below with respect to  FIG. 5 . 
     The Federal Communications Commission (FCC) implements certain Dynamic Frequency Selection (i.e., “DFS”) procedures for wireless devices that perform channel identification on 5 GHz channels. A channel that could include radar is called a “DFS channel” (or “DFS subchannel,” “restricted channel,” or “restricted subchannel,” as used herein), and a channel that could not include radar (i.e., a channel that the government does not reserve for radar signaling) is called a “non-DFS channel” (or “non-DFS subchannel,” “unrestricted channel,” or “unrestricted subchannel,” as used herein). A channel that includes both DFS and non-DFS channels is referred to as a “mixed DFS” channel. When a wireless device identifies (e.g., selects) a DFS channel or a mixed DFS channel, DFS procedures mandate that the wireless device perform a scan of the DFS or mixed DFS channel to determine if any radar signals are present on the channel before connecting. This scan is called a Channel Availability Check or “CAC.” The required CAC duration is 60 seconds for DFS channels that are reserved for “regular radar” (e.g., subchannels 52HT20, 56HT20, 60HT20, 64HT20 of the 36 VHT 160 channel, among others). The required CAC duration is 600 seconds for DFS channels that are reserved for “weather radar” (e.g., subchannel  124  of the 36 VHT 160 subchannel, among others). Example non-DFS subchannels over the 36 VHT 160 mixed DFS channel include subchannels 36, 40, 44, and 48 (i.e., 36HT20, 40HT20, 44HT20, and 48HT20, respectively). Further information regarding reserved DFS and non-DFS channel allocation, for example, for a North American 802.11ac channel, and with respect to FCC domains (UNII-1, UNII-2, etc.), Weather Radar channels, Doppler Radar channels, specific channel frequencies, and variations of channel widths is published at: http://www.mirazon.com/whats-802-11ac-keep-hearing/ 
     If a wireless device does not detect any radar signals on the DFS or mixed DFS channel during the CAC (e.g., the CAC “expires”), the wireless device is permitted to communicate over the entire DFS or mixed DFS channel. However, if the wireless device detects radar on the DFS or mixed DFS channel during the CAC, the wireless device must refrain from communicating over the channel for a 30 minute wait duration, e.g., the channel is put on a non-occupancy list (NOL) for the duration. Traditionally, a legacy wireless device in this scenario will choose a different channel and run another CAC, repeating this process until a CAC expires without radar detection. The legacy wireless device will have no communication with STAs until at least one CAC expires without radar detection, as further discussed below with respect to  FIGS. 3 and 4 . 
     If a wireless device does not detect radar during a CAC and begins to communicate over the scanned channel, DFS regulations require that the wireless device continue to “monitor” for radar, which may be referred to as “in-service monitoring” or “ISM.” If a wireless device detects radar during in-service monitoring, the detected radar may be referred to as “non-CAC radar.” If the wireless device detects non-CAC radar, similarly, regulations require that the channel be blacklisted (i.e., added to the NOL), and the wireless device must refrain from communicating over such channel for 30 minutes. Traditionally, a legacy wireless device in a non-CAC radar detection scenario will stop all communications, choose a different channel, and run another CAC, repeating this process until another CAC expires without radar detection. That is, the legacy wireless device will have no further communication with STAs until at least one CAC expires without radar detection. Such network restrictions result in slowdown and wasted resources for the wireless device, the network on which the wireless device is connected, and any wireless device that would otherwise connect to and communicate with the wireless device. 
     Thus, when wireless devices connect to mixed DFS channels (e.g., the 36 VHT 160 channel), aspects of the present disclosure enable such wireless devices to transmit over at least a portion of the mixed DFS channel (e.g., over the non-DFS subchannels), even while the wireless device scans for radar (e.g., during a CAC). To that end, systems and methods for wirelessly transmitting (e.g., via any subset of non-DFS subchannel bands on the mixed DFS channel) in parallel with listening for and/or receiving radar pulses in the entire bandwidth during a CAC are provided herein. As such, the enabled wireless device may provide uninterrupted service to STAs in parallel with performing a CAC on a mixed DFS channel. 
       FIG. 1  illustrates a wireless communication system  100  in which aspects of the present disclosure can be employed. The wireless communication system  100  may operate pursuant to a wireless standard, for example a 802.11ac standard. The wireless communication system  100  may include an AP  102 , which communicates with STAs  106   a,    106   b,    106   c,  and/or  106   d  (also individually or collectively referred to as “STA” or “STAs”). The AP  102  may also communicate with additional STAs (not pictured). The STAs may also individually or collectively operate as an AP, or vice versa. 
     A variety of processes and methods can be used for transmissions in the wireless communication system  100  between the AP  102  and the STAs  106 . For example, signals can be sent and received between the AP  102  and the STAs  106  in accordance with OFDM/OFDMA techniques. If this is the case, the wireless communication system  100  can be referred to as an OFDM/OFDMA system. Alternatively, signals can be sent and received between the AP  102  and the STAs  106  in accordance with code division multiple access (CDMA) techniques. If this is the case, the wireless communication system  100  can be referred to as a CDMA system. 
     A communication link that facilitates transmission from the AP  102  to one or more of the STAs  106  can be referred to as a downlink  108 , and a communication link that facilitates transmission from one or more of the STAs  106  to the AP  102  can be referred to as an uplink  110 . Alternatively, a downlink  108  can be referred to as a forward link or a forward channel, and an uplink  110  can be referred to as a reverse link or a reverse channel. The AP  102  may connect to one or more channels so as to communicate with the STAs  106 . The AP  102  may perform a channel identification procedure prior to connecting to one or more of the channels. The channel identification procedure and/or the channel connections may be subject to and operate in accordance with certain government regulations, e.g., DFS radar regulations, as discussed above. 
     The AP  102  may act as a base station and provide wireless communication coverage in a basic service area  104 . The AP  102  along with the STAs  106  associated with the AP  102  and that use the AP  102  for communication can be referred to as a basic service set (BSS). It should be noted that the wireless communication system  100  may not have a central AP, but rather may function as a peer-to-peer network between the STAs  106 . Accordingly, the functions of the AP  102  described herein may alternatively be performed by one or more of the STAs  106 . 
     In some aspects, a STA  106  can be required to associate with the AP  102  in order to send communications to and/or receive communications from the AP  102 . In one aspect, information for associating is included in a broadcast by the AP  102  (e.g., in a beacon; not pictured). To receive such a broadcast, the STA  106  may, for example, perform a broad coverage search over a coverage region. A search may also be performed by the STA  106  by sweeping a coverage region in a lighthouse fashion, for example. After receiving the information for associating, the STA  106  may transmit a reference signal, such as an association probe or request, to the AP  102 . In some aspects, the AP  102  may use backhaul services, for example, to communicate with a larger network, such as the Internet or a public switched telephone network (PSTN). 
     In an embodiment, the AP  102  includes an 802.11 AC-based access point for connecting to a mixed DFS channel. The AP  102  may perform some or all of the operations described herein to enable communications between the AP  102  and the STAs  106  using the 802.11. The functionality of some implementations of the AP  102  is described in greater detail below with respect to  FIGS. 2 and 5-8 . 
     Alternatively or in addition, the STAs  106  may perform some or all of the operations described herein to enable communications between the STAs  106  and the AP  102  using the 802.11 protocol. 
     In some circumstances, a basic service area can be located near other basic service areas. For example, although not pictured, the wireless communication system  100  can include multiple wireless communication networks. The basic service areas of such networks can be physically located near each other. Despite the close proximity of the basic service areas, the APs and/or STAs may each communicate using the same spectrum (e.g., 5 GHz). Thus, if a device in one basic service area (for example, one that is transmitting a radar signal, for example, a radar signal  130 ) is transmitting data, devices outside that basic service area (for example, the AP  102 ) may sense the communication (e.g., the radar signal  130 ) on the medium. 
       FIG. 2  shows a functional block diagram of an AP  402  that can be employed within the wireless communication system  100  of  FIG. 1 . The AP  402  is an example of a device that can be configured to implement the various methods described herein. For example, the AP  402  may comprise the AP  102  and/or one of the STAs  106 . 
     The AP  402  may include a processor  404  which controls operation of the AP  402 . The processor  404  may also be referred to as a central processing unit (CPU). Memory  406 , which may include both read-only memory (ROM) and random access memory (RAM), may provide instructions and data to the processor  404 . A portion of the memory  406  may also include non-volatile random access memory (NVRAM). The processor  404  typically performs logical and arithmetic operations based on program instructions stored within the memory  406 . The instructions in the memory  406  can be executable to implement the methods described herein. 
     The processor  404  may comprise or be a component of a processing system implemented with one or more processors. The one or more processors can be implemented with any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate array (FPGAs), programmable logic devices (PLDs), controllers, state machines, gated logic, discrete hardware components, dedicated hardware finite state machines, or any other suitable entities that can perform calculations or other manipulations of information. 
     The processing system may also include machine-readable media for storing software. Software shall be construed broadly to mean any type of instructions, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Instructions may include code (for example, in source code format, binary code format, executable code format, or any other suitable format of code). The instructions, when executed by the one or more processors, cause the processing system to perform the various functions described herein. 
     The AP  402  may also include a housing  408  that may include a transmitter  410  and/or a receiver  412  to allow transmission and reception of data between the AP  402  and a remote location. The transmitter  410  and receiver  412  can be combined into a transceiver  414 . An antenna  416  can be attached to the housing  408  and electrically coupled to the transceiver  414 . The AP  402  may also include (not shown) multiple transmitters, multiple receivers, multiple transceivers, and/or multiple antennas. 
     The AP  402  may also include a signal detector  418  that can be used in an effort to detect and quantify the level of signals received by the transceiver  414 . The signal detector  418  may detect such signals as total energy, energy per subcarrier per symbol, power spectral density, radar signals, and other signals. The AP  402  may also include a timer  428  that can be used together with the signal detector  418  to detect signals. For example, the signal detector  418  may scan for radar signals for a CAC duration in accordance with the timer  428 . Similarly, the AP  402  may disable communications with one or more network channels according to a NOL blacklist for a duration in accordance with the timer  428 . The AP  402  may also include a digital signal processor (DSP)  420  for use in processing signals. The DSP  420  can be configured to generate a packet for transmission. In some aspects, the packet may comprise a physical layer data unit (PPDU). In some aspects, the packet may comprise a beacon. 
     The AP  402  may further comprise a user interface  422  in some aspects. The user interface  422  may comprise a keypad, a microphone, a speaker, and/or a display. The user interface  422  may include any element or component that conveys information to a user of the AP  402  and/or receives input from the user. 
     The various components of the AP  402  can be coupled together by a bus system  426 . The bus system  426  may include a data bus, for example, as well as a power bus, a control signal bus, and a status signal bus in addition to the data bus. Those of skill in the art will appreciate the components of the AP  402  can be coupled together or accept or provide inputs to each other using some other mechanism. 
     Although a number of separate components are illustrated in  FIG. 2 , those of skill in the art will recognize that one or more of the components can be combined or commonly implemented. For example, the processor  404  can be used to implement not only the functionality described above with respect to the processor  404 , but also to implement the functionality described above with respect to the signal detector  418 , the timer  428 , the memory  406 , the transceiver  414 , the transmitter  410 , the receiver  412 , and/or the DSP  420 , etc. Further, each of the components illustrated in  FIG. 2  can be implemented using a plurality of separate elements. 
     The AP  402  may comprise an AP  102  and/or a STA  106  and can be used to transmit and/or receive communications. That is, either the AP  102  or the STA  106  may serve as a transmitter or receiver device. 
       FIG. 3  is a flowchart of a legacy method  300  for wireless communication. The legacy method  300  may be performed by a legacy device, for example, a legacy AP that does not include the benefits described in the present disclosure. At step  360 , the legacy AP performs channel identification. For example, the legacy AP may identify a mixed DFS channel for connection, e.g. the 36 VHT 160 MHz channel. Then at step  364 , according to government regulations, the legacy AP performs a CAC over the mixed DFS channel. During the CAC, STAs cannot connect to the legacy AP, as indicated in block  399 . If the legacy AP detects radar during the CAC at step  382 , then the legacy AP may return to step  360  to perform another channel identification and then another CAC at step  364 . At step  366 , if the legacy AP does not detect radar by the expiration of the CAC, then at step  370 , the legacy AP may begin transmission over the entire mixed DFS channel. 
       FIG. 4  is a time sequence diagram of a portion of the legacy method  300  for wireless communication described with respect to  FIG. 3 , which may be performed by a legacy AP  451  that does not include the benefits described in the present disclosure. At time  460 , the legacy AP  451  performs channel identification. For example, the legacy AP  451  may identify a mixed DFS channel for connection, e.g. the 36 VHT 160 MHz channel. Then at time  464 , according to government regulations, the legacy AP  451  begins a CAC  482  over the mixed DFS channel. The CAC  482  ends at time  466 , where the duration of the CAC  482  is indicated by a bracket. During the CAC  482 , STAs (e.g., the illustrated STA  456 ) cannot connect to the legacy AP  451 , and vice versa, as indicated by the no-communication indicator  499 . 
       FIG. 5  is a flowchart of a method  500  for wireless communication, in accordance with an implementation. The method  500  may be performed by an AP, for example, the AP  102  or the AP  402  discussed above with respect to  FIGS. 1 and 2 . In some aspects, the AP  402  may perform, or otherwise enable, one or more steps of method  500  in connection with one or more of the various components of the AP  402 , e.g., the processor  404 , the memory  406 , the signal detector  418 , the timer  428 , the transceiver  414 , the transmitter  410 , the receiver  412 , etc. 
     In an embodiment, the AP  402  may comprise an 802.11ac-based wireless device that identifies (e.g., selects) a 5 GHz mixed DFS channel (e.g., the 36 VHT 160 MHz channel) for connection. In one embodiment, the AP  402  may be booting up at the start of the method  500 , or in other embodiments, the AP  402  may already be operating at the start of the method  500 . In certain of the embodiments in which the AP  402  is already operating, the AP  402  may be transmitting in accordance with one of many bandwidth modes, e.g., a 160 MHz mode, an 80+80 MHz mode, an 80 MHz mode, a 40+40 MHz mode, etc., as discussed above. In some embodiments, the AP  402  may be connecting to the mixed DFS channel for the first time at the start of the method  500 , and in other embodiments, the AP  402  may already be connected to the mixed DFS channel at the start of the method  500 . 
     At step  560 , the AP  402  may perform subchannel identification on the mixed DFS channel. For example, the AP  402  may randomly identify subchannels on the mixed DFS channel, or the AP  402  may identify subchannels based on various parameters (e.g., an amount of traffic on a subchannel). The AP  402  may identify at least one restricted subchannel (e.g., a DFS subchannel) and at least one unrestricted subchannel (e.g., a non-DFS subchannel). In this example, the AP  402  identifies four restricted subchannels and four unrestricted subchannels (i.e., eight HT20 subchannels). 
     The AP  402  may establish (e.g., determine) different bandwidth configurations for the identified (e.g., selected) restricted and unrestricted subchannels. For example, the AP  402  may refrain from communicating over the identified restricted subchannels until a CAC procedure is satisfied. In an exemplary embodiment, the AP  402  may communicate over the identified unrestricted subchannels, even while performing the CAC. In one aspect, the AP  402  may initiate a bandwidth mode according to the properties of the identified subchannels. In this example, having identified four restricted subchannels, the AP  402  may reserve half of the 160 MHz bandwidth (i.e., 80 MHz) to perform a CAC, i.e., scan for radar (e.g., the radar signal  130  of  FIG. 1 ). In this example, the AP  402  may then utilize the remaining 80 MHz for communication, e.g., in a 80 MHz mode, a 40+40 MHz mode, etc. In this way, the AP  402  may be said to have established or determined a first bandwidth configuration for the identified restricted subchannels, i.e., a configuration in which the AP  402  refrains from communicating over the restricted subchannels and reserves the appropriate bandwidth for radar scanning. Similarly, the AP  402  may be said to have established or determined a second bandwidth configuration for the identified unrestricted subchannels, i.e. a configuration in which the AP  402  may communicate over the unrestricted subchannels at a bandwidth mode according to the remaining bandwidth. 
     Thus, at step  564 , according to government regulations, the AP  402  performs a CAC (or “scan”) over the mixed DFS channel. In this example, the AP  402  reserves 80 MHz of bandwidth for the scan, and the AP  402  may transmit in any subset of the unrestricted subchannels over the remaining 80 MHz of bandwidth. For example, during the scan, the AP  402  may transmit a beacon over one or more of the unrestricted subchannels to one or more other wireless devices (e.g., one or more of the STAs  106 ). In one embodiment, the beacon may include connection information for the AP  402  based at least on the above discussed second bandwidth configuration. That is, the beacon may indicate that the AP  402  is operating at, for example, an 80 MHz mode. In this way, one or more STAs  106  that receive the one or more beacons may connect to and operate with the AP  402  via some variation of the 80 MHz mode. In this way, during the scan, the STAs  106  may communicate with the AP  402 , as indicated in indicator  598  and in accordance with embodiments of the present disclosure. 
     At step  566 , if the AP  402  does not detect radar by the expiration of the CAC, then in one embodiment, the AP  402  may initiate a bandwidth step up. That is, the AP  402  may initiate an 80+80 MHz mode or a 160 MHz mode for communication over the entire mixed DFS channel. In this way, the AP  402  may be said to have established or determined a third bandwidth configuration for all of the identified subchannels. 
     Then at step  568 , the AP  402  may transmit a bandwidth switch announcement (BSA). For example, the AP  402  may transmit one or more beacons over one or more of the identified unrestricted subchannels, the beacons including at least the BSA. In an aspect, the BSA may include connection information related to the determined third bandwidth configuration, e.g. that the AP  402  is operating at (or, as the case may be, has stepped up to) an 80+80 MHz mode or a 160 MHz mode. When the BSA indicates that the AP  402  has stepped up the bandwidth mode, it can be referred to as a bandwidth “expansion.” 
     Thus, at step  570 , the AP  402  may start full transmission over one or more (or all) of the identified subchannels. 
     In some embodiments, the AP  402  may detect radar (e.g., the radar signal  130 ) during the CAC at step  582 , and in one embodiment, the AP  402  may then return to step  560  to perform another subchannel identification. Within this time, the AP  402  may maintain communication over the non-DFS subchannels, as further discussed below with respect to  FIG. 7 . 
     In some embodiments, the AP  402  may detect non-CAC radar (e.g., the radar signal  130 ), for example, after starting full transmission at step  570 . Similarly, within this time, the AP  402  may maintain communication over the non-DFS subchannels, as further discussed below with respect to  FIG. 7 . 
       FIG. 6  is a time sequence diagram of a portion of the method  500  for wireless communication described with respect to  FIG. 5 . The time sequence diagram includes an AP  652 , which may comprise the AP  102  and/or the AP  402  discussed above with respect to  FIGS. 1, 2, and 5 . The time sequence diagram also includes a STA  656 , which may comprise one or more of the STAs  106  discussed above with respect to  FIGS. 1 and 5 . 
     At time  660 , the AP  652  performs subchannel identification on the mixed DFS channel as described above with respect to step  560  of  FIG. 5 . In this example, the AP  652  identifies at least one restricted subchannel and at least one unrestricted subchannel. 
     At time  662 , the AP  652  determines bandwidth configurations for the identified subchannels as further described above with respect to step  560  of  FIG. 5 . In this example, the AP  652  determines a first bandwidth configuration for the identified restricted subchannels such that the AP  652  refrains from communicating over such channels, instead reserving 80 MHz (for example) to perform a radar scan. In this example, the AP  652  determines a second bandwidth configuration for the identified unrestricted subchannels such that the AP  652  communicates over the unrestricted subchannels at a 80 MHz (for example) mode. 
     At time  664 , the AP  652  initiates a scan (e.g., a CAC) for detecting one or more restricted signals (e.g., radar) over one or more of the identified restricted subchannels, as described above with respect to  FIG. 5 . During the CAC  682 , STAs (e.g., the STA  656 ) may communicate with the AP  652 . For example, during the CAC  682 , the AP  652  may transmit a beacon  698  to the STA  656  over one or more of the identified unrestricted subchannels, as discussed above with respect to step  564  and indicator  598  of  FIG. 5 . In this way, during the CAC  682 , the STA  656  may communicate with the AP  652 . 
     At time  666 , the CAC  682  may expire without detection of radar and the AP  652  may then initiate a bandwidth step up, as described above with respect to step  566  of  FIG. 5 . 
     Then after the CAC  682 , the AP  652  may transmit a BSA  668  to the STA  656 , as discussed above with respect to step  568  of  FIG. 5 . The BSA  668  may be included in a beacon, for example, and may indicate connection information related to the AP  652 , such as information regarding the bandwidth step up mentioned above. 
     In some embodiments, the AP  652  may detect radar (e.g., the radar signal  130  described in connection with  FIG. 1 ) during the CAC  682 , and in one embodiment, the AP  652  may then perform another subchannel identification, or may perform different actions, while maintaining communication over the non-DFS subchannels, as further discussed below with respect to  FIG. 7 . 
     In some embodiments, the AP  652  may detect non-CAC radar (e.g., the radar signal  130 ), for example, after the CAC  682 , and then perform various actions. Similarly, within this time, the AP  652  may maintain communication over the non-DFS subchannels, as further discussed below with respect to  FIG. 7 . 
       FIG. 7  is a flowchart of a method  700  for wireless communication, in accordance with an implementation. The method  700  may be performed by an AP, for example, the AP  102 , the AP  402 , and/or the AP  652  described above with respect to  FIGS. 1, 2, 5, and 6 . In some aspects, the AP  402  may perform, or otherwise enable, one or more steps of method  700  in connection with one or more of the various components of the AP  402 , e.g., the processor  404 , the memory  406 , the signal detector  418 , the timer  428 , the transceiver  414 , the transmitter  410 , the receiver  412 , etc. 
     The AP  402  may comprise or otherwise operate according to any number of the aspects described with respect to the AP  402  in the description of the method  500  of  FIG. 5 . Furthermore, indicator  798  and steps  760 ,  764 ,  766 ,  768 ,  770 , and  782  of method  700 , may correspond, all or in part, to indicator  598  and steps  560 ,  564 ,  566 ,  568 ,  570 , and  582  of method  500 , respectively, described above with respect to  FIG. 5 . 
     In some embodiments, the AP  402  may detect radar (e.g., the radar signal  130 ) during the CAC at step  782 , and the AP  402  may then proceed to step  776  to perform a subchannel identification according to one or more subchannel identification embodiments described herein. Within this time, the AP  402  may maintain communication with one or more STAs (e.g., one or more STAs  106  described with respect to  FIG. 1 ) over the non-DFS subchannels. 
     For example, in one embodiment, the AP  402  may disconnect (e.g., unselect or unidentify) from the one or more restricted subchannels over which radar was detected, e.g., place said subchannels on a NOL. Then, the AP  402  may identify at least one different restricted subchannel. The AP  402  may identify the at least one different restricted subchannels according to a random identification or according to a different type of identification. For example, the AP  402  may identify a different subchannel according to a traffic level of the subchannel. In some embodiments, the AP  402  may also identify one or more different unrestricted subchannels according to a random channel identification or a different type of identification. In some embodiments, the AP  402  may randomly identify one different restricted subchannel and randomly identify one different unrestricted subchannel, which may be referred to as a random pair identification. 
     When the AP  402  identifies one or more different restricted subchannels and/or unrestricted subchannels, the AP  402  may re-determine, or maintain the determination of, bandwidth configurations accordingly. For example, the AP  402  may determine a first bandwidth configuration for all of the identified restricted subchannels, as described above with respect to step  560  of  FIG. 5 . As another example, the AP  402  may determine a second bandwidth configuration for all of the identified unrestricted subchannels, as further described above with respect to step  560  of  FIG. 5 . For example, in some embodiments, the AP  402  may initiate a bandwidth step down when the radar is detected. In other embodiments, the AP  402  may maintain a stepped down bandwidth (e.g., 80 MHz) when the radar is detected. 
     Returning to step  770 , in some embodiments, the AP  402  may not detect any radar (e.g., a radar signal  130  as described with respect to  FIG. 1 ), for example, after starting full transmission at step  770 . In this case, the method  700  may be said to end at step  772 . Alternatively, the AP  402  may detect non-CAC radar (e.g., the radar signal  130 ), for example, after starting full transmission at step  770 . That is, at step  774 , the AP  402  may detect the radar signal  130  during in-service monitoring (ISM). In this case, the AP  402  may also continue to step  776  and perform a subchannel identification according to one or more of the subchannel identification embodiments discussed above. 
     After the subchannel identification, the AP  402  may then transmit a bandwidth switch announcement (BSA). For example, the AP  402  may transmit one or more second beacons over one or more of the identified unrestricted subchannels, the second beacons including at least the BSA. In an aspect, the BSA may be similar to the BSA described with respect to step  568  of  FIG. 5 , except that the BSA may indicate that the AP  402  has stepped down the bandwidth mode, and thus, the BSA may be referred to as a bandwidth “contraction.” 
     In some embodiments, the BSA may be optional when the AP  402  does not step down the bandwidth mode at step  776 . For example, the AP  402  may already be operating at a stepped down 80 MHz mode during the CAC at step  764 , then detect radar at step  782 , then identify one or more new subchannels at step  776 , and then return to step  764  to perform a second CAC, each of such steps being performed while maintaining operation at the stepped down 80 MHz mode. Thus, as the bandwidth mode did not change in this scenario, the AP  402  does not send a BSA at step  778 , instead continuing directly from step  776  to step  764 , as indicated by the dashed arrow. 
     In an alternative embodiment, at step  776 , the AP  402  may not identify any new unrestricted subchannels and may not identify any new restricted subchannels. Instead, the AP  402  may wait a predetermined duration before initiating a second scan (e.g., another CAC) of the same identified restricted subchannels at step  764 . The predetermined duration may be a government regulated duration (e.g., 30 minutes), during which the restricted subchannel or subchannels may be placed on a NOL (i.e., blacklisted), as described above. In such an alternative embodiment, within the predetermined duration, the AP  402  may continue to communicate with one or more of the STAs  106  over one or more of the unrestricted subchannels. After the predetermined duration, the AP  402  may then continue directly to step  764  to perform another CAC on the restricted subchannels, as indicated by the dashed arrow. 
     Thus, continuing from one of steps  776  or  778 , at step  764 , the AP  402  performs another CAC. The AP  402  may then proceed to step  782  or step  766 , depending on the results of the CAC. During the CAC, and during the above described embodiments of method  700 , the AP  402  may maintain communication over the identified non-DFS subchannels, for example, by transmitting one or more beacons to one or more of the STAs  106 . As such, the AP  402  may provide uninterrupted service to the STAs  106  in parallel with performing one or more CACs on the mixed DFS channel. 
       FIG. 8  is a flowchart of a method for wireless communication, in accordance with an exemplary embodiment. The method  800  may be performed by an AP, for example, the AP  102 , the AP  402 , and/or the AP  652  described above with respect to  FIGS. 1, 2, and 5-7 . In some aspects, the AP  402  may perform, or otherwise enable, one or more steps of method  700  in connection with one or more of the various components of the AP  402 , e.g., the processor  404 , the memory  406 , the signal detector  418 , the timer  428 , the transceiver  414 , the transmitter  410 , the receiver  412 , etc. 
     At step  801 , in some aspects, the AP  402  may identify a plurality of subchannels of a transmission channel for transmission, the identified plurality of subchannels including one or more restricted subchannels and including one or more unrestricted subchannels. The AP  402  may perform such aspects in accordance with the descriptions related to step  560 , time  660 , and/or step  760  of  FIGS. 5, 6, and 7 , respectively. Furthermore, the AP  402  may perform such aspects in accordance with the descriptions related to step  776  of  FIG. 7 . In one example, in addition to or in connection with the AP  402 , means for performing such aspects may include, for example, the processor  404  of the AP  402 , described in connection with  FIG. 4  above. 
     At step  802 , in some aspects, the AP  402  may determine a first bandwidth configuration for the identified restricted subchannels and a second bandwidth configuration for the identified unrestricted subchannels. The AP  402  may perform such aspects in accordance with the descriptions related to step  560 , time  662 , and/or step  760  of  FIGS. 5, 6, and 7 , respectively. Furthermore, the AP  402  may perform such aspects in accordance with the descriptions related to step  776  of  FIG. 7 . In one example, in addition to or in connection with the AP  402 , means for performing such aspects may include, for example, the processor  404  of the AP  402 , described in connection with  FIG. 4  above. 
     At step  803 , in some aspects, the AP  402  may scan, by a signal detector, for one or more restricted signals over one or more of the identified restricted subchannels. The AP  402  may perform such aspects in accordance with the descriptions related to step  564 , time  664 , and/or step  764  of  FIGS. 5, 6, and 7 , respectively. In one example, in addition to or in connection with the AP  402 , means for performing such aspects may include, for example, the signal detector  418  of the AP  402 , described in connection with  FIG. 4  above. 
     At step  804 , in some aspects, the AP  402  may transmit a beacon to a wireless device within a duration of the scanning, the beacon being transmitted over one or more of the identified unrestricted subchannels. The AP  402  may perform such aspects in accordance with the descriptions related to step  564 , beacon  698 , and/or step  764  of  FIGS. 5, 6, and 7 , respectively. In one example, in addition to or in connection with the AP  402 , means for performing such aspects may include, for example, the transmitter  410 , the receiver  412 , and/or the transceiver  414  of the AP  402 , described in connection with  FIG. 4  above. 
     As used herein, the term “determining” and/or “identifying” encompass a wide variety of actions. For example, “determining” and/or “identifying” may include calculating, computing, processing, deriving, choosing, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, identifying, establishing, selecting, choosing, determining and the like. Further, a “channel width” as used herein may encompass or may also be referred to as a bandwidth in certain aspects. 
     As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c. 
     The various operations of methods described above may be performed by any suitable means capable of performing the operations, such as various hardware and/or software component(s), circuits, and/or module(s). Generally, any operations illustrated in the Figures may be performed by corresponding functional means capable of performing the operations. 
     As used herein, the term interface may refer to hardware or software configured to connect two or more devices together. For example, an interface may be a part of a processor or a bus and may be configured to allow communication of information or data between the devices. The interface may be integrated into a chip or other device. For example, in some embodiments, an interface may comprise a receiver configured to receive information or communications from a device at another device. The interface (e.g., of a processor or a bus) may receive information or data processed by a front end or another device or may process information received. In some embodiments, an interface may comprise a transmitter configured to transmit or communicate information or data to another device. Thus, the interface may transmit information or data or may prepare information or data for outputting for transmission (e.g., via a bus). 
     The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) signal or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     In one or more aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects, computer readable medium may comprise non-transitory computer readable medium (e.g., tangible media). In addition, in some aspects computer readable medium may comprise transitory computer readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media. 
     Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For certain aspects, the computer program product may include packaging material. 
     The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. 
     Software or instructions may also be transmitted over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of transmission medium. 
     Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by an AP  102  and/or another device as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that an AP  102  and/or another device can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized. 
     It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims. 
     While the foregoing is directed to aspects of the present disclosure, other and further aspects of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.