PATENT DOCUMENT

Publication Number: US-10601429-B2
Application Number: US-201816031602-A
Country: US
Kind Code: B2

Title: Apparatus and method for Bluetooth scan

Abstract:
Methods and systems for substantially simultaneously scan of two or more frequencies using one transceiver are discussed herein. For example, a listening device can include a controller configured to control its transceiver to alternate between two or more frequencies from two or more sets of frequencies. The controller is also configured to capture a portion of a preamble of a received signal to determine whether the received signal is intended for the listening device.

Claims:
What is claimed is: 
     
       1. A method, comprising:
 configuring a transceiver of a device to operate at a first frequency of a first set of frequencies; 
 receiving a signal from the transceiver; 
 capturing a portion of a preamble from the signal; 
 determining, based at least in part on the captured portion of the preamble and before capturing a remainder of the preamble, whether the received signal is intended for the device; and 
 in response to determining that the received signal is not intended for the device, configuring the transceiver to operate at a second frequency of a second set of frequencies. 
 
     
     
       2. The method of  claim 1 , further comprising:
 in response to determining that the received signal is intended for the device,
 permitting the transceiver of the device to continue operation at the first frequency of the first set of frequencies; and 
 capturing the remainder of the preamble and a payload from the received signal. 
 
 
     
     
       3. The method of  claim 2 , further comprising:
 sending a signal to a data acquisition circuit, wherein the capturing the remainder of the preamble and the payload from the received signal is performed by the data acquisition circuit. 
 
     
     
       4. The method of  claim 1 , wherein configuring the transceiver of the device to operate at the first frequency of the first set of frequencies comprises:
 controlling a phase locked loop (PLL) of the transceiver to operate at the first frequency of the first set of frequencies. 
 
     
     
       5. The method of  claim 1 , further comprising:
 periodically switching between the first frequency of the first set of frequencies and the second frequency of the second set of frequencies during a page scan window. 
 
     
     
       6. The method of  claim 1 , wherein the first set of frequencies is associated with a connection establishment according to a Bluetooth™ protocol, a Bluetooth™ Low Energy protocol, or a Bluetooth™ Low Energy Long Range protocol. 
     
     
       7. The method of  claim 6 , wherein the second set of frequencies is associated with a connection establishment according to the Bluetooth™ protocol, the Bluetooth™ Low Energy protocol, or the Bluetooth™ Low Energy Long Range protocol. 
     
     
       8. The method of  claim 1 , wherein the captured portion of the preamble comprises at least a beginning of the preamble. 
     
     
       9. The method of  claim 1 , wherein configuring the transceiver of the device to operate at the first frequency of the first set of frequencies comprises:
 controlling a multiplexer of the transceiver to select between an output of a first phase locked loop (PLL) operating at the first frequency of the first set of frequencies and an output of a second PLL operating at the second frequency of the second set of frequencies. 
 
     
     
       10. A method, comprising:
 periodically switching between a first frequency of a first set of frequencies and a second frequency of a second set of frequencies at which a transceiver of a first device operates; 
 capturing a portion of a preamble from a signal received from a second device; 
 determining, based at least in part on the captured portion of the preamble and before capturing a remaining portion of the preamble, whether the received signal is intended for the first device; and 
 in response to determining that the received signal is not intended for the device, continuing the periodical switching between the first frequency of the first set of frequencies and the second frequency of the second set of frequencies. 
 
     
     
       11. The method of  claim 10 , further comprising:
 in response to determining that the received signal is intended for the first device,
 ceasing the periodical switching between the first and second set of frequencies; and 
 capturing the remaining portion of the preamble and a payload from the received signal; and 
 
 establishing a connection between the first device and the second device based on the captured remaining portion of the preamble and the payload from the received signal. 
 
     
     
       12. The method of  claim 11 , further comprising:
 sending a signal to a data acquisition circuitry, wherein the capturing the remaining portion of the preamble and the payload from the received signal is performed by the data acquisition circuitry. 
 
     
     
       13. A system, comprising:
 a transceiver comprising a phase lock loop (PLL); and 
 a controller communicatively coupled to the transceiver, the controller configured to:
 configure the PLL of the transceiver to operate at a first frequency of a first set of frequencies; 
 capture a portion of a preamble from a signal received using the transceiver; 
 determine, based at least in part on the captured portion of the preamble and before capturing a remainder of the preamble, whether the received signal is intended for the system; and 
 in response to determining that the received signal is not intended for the system, configure the PLL to operate at a second frequency of a second set of frequencies. 
 
 
     
     
       14. The system of  claim 13 , wherein the controller is further configured to:
 in response to determining that the received signal is intended for the system,
 permit the PLL to continue operation at the first frequency of the first set of frequencies; and 
 capture the remainder of the preamble and a payload from the received signal. 
 
 
     
     
       15. The system of  claim 13 , further comprising:
 a data acquisition circuitry communicatively coupled to the transceiver and the controller, 
 wherein the controller is further configured to, in response to determining that the received signal is intended for the system, send a signal to the data acquisition circuitry to capture the remainder of the preamble and a payload from the received signal. 
 
     
     
       16. The system of  claim 13 , wherein the controller is further configured to:
 control the PLL to periodically switch between the first frequency of the first set of frequencies and the second frequency of the second set of frequencies during a page scan window. 
 
     
     
       17. The system of  claim 13 , wherein the controller comprises:
 a first detector configured to determine, based at least in part on the captured portion of the preamble, whether the received signal is intended for the system when the PLL operates at the first frequency of the first set of frequencies. 
 
     
     
       18. The system of  claim 17 , wherein the controller further comprises:
 a second detector configured to determine, based at least in part on the captured portion of the preamble, whether the received signal is intended for the system when the PLL operates at the second frequency of the second set of frequencies. 
 
     
     
       19. The system of  claim 13 , wherein the transceiver further comprises:
 a second PLL; and 
 a multiplexer communicatively coupled to the PLL and the second PLL, 
 wherein the controller is configured to control the multiplexer to select between an output of the PLL and an output of the second PLL. 
 
     
     
       20. The system of  claim 13 , wherein the captured portion of the preamble comprises at least a beginning of the preamble.

Description:
BACKGROUND 
     Field 
     This disclosure generally relates to techniques for implementing a scan mechanism for Bluetooth™ devices. 
     Related Art 
     Bluetooth™ devices can use paging and scanning to establish connections. A listening Bluetooth™ device is configured to scan different channels to determine whether any of the channels include packets addressed to the listening Bluetooth™ device. A tradeoff exists between how fast the listening Bluetooth™ device can connect to another Bluetooth™ device and the battery life of the listening Bluetooth™ device. For example, for the listening device to connect faster to the other device, the listening device scans the channels more often and therefore more battery of the listening device is used. On the other hand, to preserve the battery, the listening device can scan the channels less often, which can result in added delay in connecting to the transmitting device. 
     SUMMARY 
     The described embodiments relate to methods and systems for substantially simultaneously scanning two or more frequencies using one transceiver. For example, a listening device can include a controller configured to control the transceiver of the listening device to alternate between two or more frequencies from two or more sets of frequencies. The controller is also configured to capture part of a preamble of a received signal to determine whether the received signal is intended for the listening device. 
     Some embodiments relate to a method including configuring a transceiver of a device to operate at a first frequency of a first set of frequencies. The method further includes receiving a signal from the transceiver and capturing a portion of a preamble from the signal. The method also includes determining, based at least in part on the captured portion of the preamble and before capturing a remainder of the preamble, whether the received signal is intended for the device. In response to determining that the received signal is not intended for the device, configuring the transceiver of the device to operate at a second frequency of a second set of frequencies. However, in response to determining that the received signal is intended for the device, the method includes permitting the transceiver of the device to continue operation at the first frequency of the first set of frequencies and capturing the preamble and a payload of the received signal. 
     Some embodiments relate to a method including periodically switching between a first frequency of a first set of frequencies and a second frequency of a second set of frequencies at which a transceiver of a first device operates. The method further includes capturing a portion of a preamble from a signal received from a second device and determining, based at least in part on the captured portion of the preamble and before capturing a remaining portion of the preamble, whether the received signal is intended for the device. In response to determining that the received signal is not intended for the first device, the method includes continuing the periodical switching between the first frequency and the second frequency. In response to determining that the received signal is intended for the first device, the method includes ceasing the periodic switching between the first and second set of frequencies and capturing the remaining portion of the preamble and a payload from the received signal. The method further includes establishing a connection between the first device and the second device. 
     Some embodiments relate to a device. The device includes a memory and a processor, communicatively coupled to the memory. The processor is configured to configure a transceiver of the device to operate at a first frequency of a first set of frequencies, receive a signal from the transceiver, and capture a portion of a preamble of the signal. The processor is further configured to determine, based at least in part on the captured portion of the preamble and before capturing a remainder of the preamble, whether the received signal is intended for the device. In response to determining that the received signal is not intended for the device, the processor is configured to configure the transceiver of the device to operate at a second frequency of a second set of frequencies. In response to determining that the received signal is intended for the device, the processor is configured to permit the transceiver of the device to continue operation at the first frequency of the first set of frequencies and capture the preamble and a payload of the received signal. 
     Some embodiments relate to a system. The system includes a transceiver comprising a phase lock loop (PLL) and a controller communicatively coupled to the transceiver. The controller is configured to configure the PLL of the transceiver to operate at a first frequency of a first set of frequencies and capture a portion of a preamble from the signal received from the transceiver. The controller is further configured to determine, based at least in part on the captured portion of the preamble and before capturing a remainder of the preamble, whether the received signal is intended for the system. In response to determining that the received signal is not intended for the device, the controller is configured to configure the PLL to operate at a second frequency of a second set of frequencies. 
     This Summary is provided merely for purposes of illustrating some embodiments to provide an understanding of the subject matter described herein. Accordingly, the above-described features are merely examples and should not be construed to narrow the scope or spirit of the subject matter in this disclosure. Other features, aspects, and advantages of this disclosure will become apparent from the following Detailed Description, Figures, and Claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the presented disclosure and, together with the description, further serve to explain the principles of the disclosure and enable a person of skill in the relevant art(s) to make and use the disclosure. 
         FIG. 1A  is a functional block diagram depicting an example device in an environment with a plurality of devices, according to some embodiments. 
         FIG. 1B  is a diagram depicting an example communication between two devices, according to some embodiments. 
         FIG. 2  is a functional block diagram depicting an example system implementing a scan method, according to some embodiments of the disclosure. 
         FIG. 3  is a functional block diagram depicting an example system implementing a detector, according to some embodiments. 
         FIGS. 4A-4C  depict example timing diagrams of a scan signal transmitted by a device, according to some embodiments. 
         FIG. 5A  is a functional block diagram depicting another example system implementing a scan method, according to some embodiments. 
         FIG. 5B  is a diagram depicting an example timing of a scan signal transmitted by a transceiver of a device, according to some embodiments. 
         FIG. 6A  is a functional block diagram depicting another example system implementing a scan method for scanning between four frequencies, according to some embodiments. 
         FIG. 6B  depicts example timing diagrams of scan signals for two transceivers of a device, according to some embodiments. 
         FIG. 7  is a flowchart depicting an example method for substantially simultaneously scanning two or more frequencies using one receiver, according to some embodiments. 
         FIG. 8  is an example computer system useful for implementing some embodiments or portion(s) thereof. 
     
    
    
     The presented disclosure is described with reference to the accompanying drawings. In the drawings, generally, like reference numbers indicate identical or functionally similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. 
     DETAILED DESCRIPTION 
       FIG. 1A  is a functional block diagram depicting an example of an environment  100  with a plurality of devices  104   1 - 104   8  (also generically referred to herein as device  104 ), according to some embodiments.  FIG. 1A  shows that device  104   1  can be connected to one or more other devices  104   2-8  via connections  106   2-8 . The device  104   1  may be a device from a wide assortment of different devices. For instance, the device  104   1  may be selected from any/all of laptop computers, desktop computers, smart phones, tablet computers, wearable devices (such as an Apple Watch™), human interface devices, speaker devices, headphone devices, multimedia devices (such as an Apple TV™), mobile multimedia devices (e.g. a head unit), etc. Similar to the device  104   1 , the devices  104   2-7  can be selected from a wide assortment of different devices, such as the devices listed above. It is to be appreciated that environment  100  may include other devices in addition to or in place of the devices illustrated in  FIG. 1A  without departing from the scope and spirit of this disclosure. 
     The connections  106   2-8  are illustrated in  FIG. 1A  as possible connections between the device  104   1  and the devices  104   2-8 . Based on the disclosure herein, a person of ordinary skill in art will understand that each of the devices  104   1-8  can form one or more connections with other devices  104   1-8 . As one example, the device  104   1  can form a connection with either or both of the devices  104   2  and  104   3 . One or all of the connections  106   2-8  (and other connections between other devices  104   1-8 ) may be wireless and may include, but are not limited to, a cellular network connection (such as but not limited to Universal Mobile Telecommunications System (UMTS) or with the Long-Term Evolution (LTE)), a wireless local network connection (such as but not limited to Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, which is sometimes referred to as Wi-Fi, or based on Bluetooth™ or Bluetooth™ Low Energy from the Bluetooth Special Interest Group of Kirkland, Wash.), or any other wireless connections using standardized and/or proprietary protocols. In some embodiments, one, multiple, or all of connections  106   2-8  may be implemented as wired connections between each of the respective devices. 
     As a non-limiting example, the device  104   1  may establish a wireless connection  106   8  with the device  104   8 . The wireless connection  106   8  may be a connection based on any of the Bluetooth™ protocol, a Bluetooth™ Low Energy protocol, or a Bluetooth™ Low Energy Long Range protocol. To establish the wireless connection  106   8  for the first time, the devices  104   1  and  104   8  may perform a pairing operation. The pairing operation may include an inquiry and/or a paging from a master (or “primary”) device (e.g., the device  104   8 ) and scanning from a slave (or “secondary”) device (e.g., the device  104   1 .) For example, if the device  104   8  does not know an identifier (e.g., an address) of the device  104   1 , the device  104   8  may transmit an inquiry message such that a slave device (e.g., the device  104   1 ) may respond with its identifier. Additionally or alternatively, the device  104   8  may transmit a page message with the identifier of the device  104   1 . The device  104   8  can transmit the page message over different frequencies. The device  104   1  scans the different frequencies and can detect the page message. When the device  104   1  detects a page message destined for the device  104   1 , the device  104   1  may establish the connection  106   8  with the device  104   8 . 
       FIG. 1B  is a diagram  120  depicting an example communication by a device  124  (e.g., device  104   8  from  FIG. 1A ) to a device  122  (e.g., device  104   1  from  FIG. 1A ) when the devices attempt to establish a communication connection with one another, according to some embodiments. The example signals in diagram  120  are plotted against a time axis  132 . As shown in  FIG. 1B , the device  124  may transmit a series of signal trains  126 , in which each signal train includes one or more pages  130 . The example of  FIG. 1A  depicts the signal trains  126  as Train A and Train B, but more or fewer trains could be used in accordance with the scope and spirit of this disclosure. In some embodiments, the signal trains  126  may be implemented as Bluetooth™ pages, Bluetooth™ Low Energy pages, and/or a Bluetooth™ Low Energy Long Range pages. Each of the trains has a particular duration. For instance, as shown in the example of  FIG. 1B , Train A has a duration of T P1  and Train B has a duration of T P2 . The respective durations of the trains, e.g., Train A and Train B, can be the same or can differ. Furthermore, the trains, e.g., Train A and Train B, may be transmitted on the same channel or on different channels. 
     The device  122  may periodically open a page scan window  128  such as, for example, page scan windows  128 A and  128 B shown in  FIG. 1B . The page scan window  128 A may roughly correspond to Train A transmitted by the device  124 . Similarly, the page scan window  128 B may roughly correspond to Train B transmitted by the device  124 . Each of the page scan windows  128 A and  128 B may also have a corresponding duration (or period). For instance, the page scan window  128 A can have a duration T W1  and the page scan window  128 B can have a duration T w2 . It should be noted, that  FIG. 1B  is merely for illustrative purposes and no attempt has been made to depict the windows  128  of the device  122  and the transmissions of the device  124  to either a relative or absolute scale. 
     In some embodiments, the device  122  detects, during the page scan window  128 , one or more of the pages  130  associated with one of the trains  126  transmitted by the device  124 . Once the device  122  detects a page  130  transmitted by the device  124 , the procedure for establishing a connection can be followed, and the device  124  and the device  122  form a connection—e.g., the connection  106   8  from  FIG. 1A . 
     In some examples, the frequencies on which the device  124  transmits the page message can include a plurality of sets of frequencies. For example, for a connection establishment according to the Bluetooth™ protocol, the frequencies on which the device  122  transmits the page message can include two sets of frequencies, each set including, e.g.,  16  different frequencies. The device  124  transmits the pages over the first set of frequencies for a period of time using, for example, Train A that has a duration of T P1 . If the device  122  receives no response (for example from the device  124 ), the device  122  transmits the pages over the second set of frequencies using, for example, Train B that has a duration of T P2 . In this example, the device  122  opens the page scan window  128 A to scan for frequencies associated with the first set of frequencies. The device  122  opens the page scan window  128 B to scan for frequencies associated with the second set of frequencies. 
     In some examples, at least a third set of frequencies can be assigned for connection establishment according to the Bluetooth™ Low Energy protocol and/or at least a fourth set of frequencies can be assigned for connection establishment according to the Bluetooth™ Low Energy Long Range protocol. 
     According to some examples, when the devices  122  and  124  would like to connect again after the initial connection and pairing, the device  122  can use a specific frequency in each of the plurality of sets of frequencies to scan the channel associated with that specific frequency. This specific frequency can be based on the frequency used during initial pairing. In conventional methods, a slave device would scan a channel using a frequency from a first set of frequencies for a first period of time. If the slave device does not find any paging message addressed to the slave device, the slave device would scan a channel using a frequency from a second set of frequencies for a second period of time. If the slave device does not find any pages addressed to the slave device, the slave device would scan a channel using a frequency from a third set of frequencies for a third period of time. The slave device can perform this operation for all the plurality of the sets of frequencies. 
     Since page scanning can consume a significant amount of power, it can be advantageous to reduce the size of the page scan windows  128 . For example, using shorter page scan windows  128  can reduce power consumption, thereby prolonging battery life. However, when the page scan window is too small, the page scan window  128  may not align with pages  130  transmitted by the device  124 . Consequently, several page scan windows  128  may be needed for the device  122  to detect one or more pages  130  transmitted by the device  124 . This can delay connection establishment between the device  124  and the device  122 . 
     In some of the embodiments of this disclosure, the device  122  is configured to substantially simultaneously scan two or more frequencies using only one transceiver. For example, the device  122  substantially simultaneously scans a channel associated with a frequency from a first set of frequencies and a channel associated with a frequency from a second set of frequencies. However, in other embodiments, any combination of frequencies can be scanned. In one example regarding the initial connection and pairing between the devices  122  and  124 , during the page scan window  128 A, the device  122  may substantially simultaneously scan a first frequency of a first set of frequencies (for example the first set associated with Train A transmitted by the device  124 ) and a second frequency for a second set of frequencies (for example the second set associated with Train B transmitted by the device  124 .) In other words, the device  122  can scan with respect to two sets of frequencies (associated with Train A and Train B) during page scan window  128 A. Accordingly, a connection can be established more quickly and battery/power consumption associated with scanning and paging can be reduced. However, it is noted that the embodiments of this disclosure are not limited to the initial connection and pairing. The embodiments of this disclosure are also applied when devices, e.g., the devices  122  and  124 , would like to connect again after the initial connection and pairing. 
     In some examples, the first set of frequencies and the second set of frequencies are associated with connection establishment according to the Bluetooth™ protocol. In other examples, the first set of frequencies is associated with connection establishment according to the Bluetooth™ protocol and the second set of frequencies is associated with connection establishment according to the Bluetooth™ Low Energy protocol. In further examples, the first set of frequencies is associated with connection establishment according to the Bluetooth™ protocol and the second set of frequencies is associated with connection establishment according to the Bluetooth™ Low Energy Long Range protocol. In yet other examples, the first set of frequencies is associated with connection establishment according to the Bluetooth™ Low Energy protocol and the second set of frequencies is associated with connection establishment according to the Bluetooth™ Low Energy Long Range protocol. It is noted that these sets of frequencies and their combinations are provided as examples and they do not limit the embodiments of this disclosure. Based on the disclosure herein, a person of ordinary skill in the art will understand that other sets and other combinations can exist. 
       FIG. 2  is a functional block diagram depicting an example system implementing a scan method, according to some embodiments of the disclosure. System  200  of  FIG. 2  can be implemented within one or more devices of  FIG. 1A . 
     System  200  includes a transceiver  210 , a controller  230 , and a data acquisition circuitry  250 . It is noted that the transceiver  210 , the controller  230 , and the data acquisition circuitry  250  are depicted as exemplary components of the system  200 , and the system  200  can include other components. 
     As illustrated in the example of  FIG. 2 , the transceiver  210  includes an amplifier  211 , a mixer  213 , a phase-locked loop (PLL)  215 , a filter  217 , and a converter  219 , according to some embodiments. In some examples, the amplifier  211  can include, but is not limited to, a low noise amplifier (LNA). The converter  219  can also include, but is not limited to, an analog to digital converter. According to some embodiments, the transceiver  210  may be configured to receive an input signal using, for example, an antenna that is communicatively coupled to the amplifier  211 . The received input signal is amplified by the amplifier  211 . The amplified signal is then mixed, using the mixer  213 , with a signal from PLL  215 . The input signal can include one or more pages from, for example, device  104   8 . 
     According to some embodiments, and as discussed in more detail below, the PLL  215  can be controlled by the controller  230  such that the output signal of the PLL  215  includes a selected frequency and/or a selected frequency band. The amplified received input signal (e.g., an amplified radio frequency (RF) signal) and the output signal of the PLL  215  are input to the mixer  213 . According to some embodiments, the mixer  213 , using the output signal of the PLL  215 , is configured to downconvert the amplified received input signal. Therefore, the output of the mixer  213  includes a baseband signal or an intermediate frequency (IF) signal determined based on the frequency of the output signal from the PLL, according to some embodiments. According to some examples, the PLL  215  can include a fast-lock PLL. For example, the PLL  215  can have approximately a 1 μsec lock time with +/−100 KHz. The mixed signal output of the mixer  213  can pass through the filter  217 . The filter  217  can include a low pass filter, a bandpass filter, and/or other filters. The filtered signal can be converted from analog to digital using the converter  219  to generate the digital signal  220 . The digital signal  220  then is fed to the controller  230  and the data acquisition circuitry  250 . It is noted that the components of the transceiver  210  discussed above are exemplary circuits and/or modules and the transceiver  210  can include fewer, different, or additional circuits/modules. 
     The controller  230  can be communicatively coupled to the transceiver  210 . For example, the controller  230  can control PLL  215  of the transceiver  210 . Additionally, the controller  230  can receive the signal  220  from the transceiver  210 . According to some embodiments, the controller  230  can include a state machine  231  and one or more detectors  233 A and  233 B (collectively referred to as detector  233 ). Optionally, the controller  230  can include one or more digital muting masks  235 A and  235 B (collectively referred to as digital muting mask  235 .) It is noted that the depicted components of the controller  230  are exemplary circuits and/or modules, and the controller  230  can include fewer, different, or additional circuits/modules. 
     According to some embodiments, the controller  230  controls the PLL  215  of the transceiver  210 . For example, the controller  230  controls the frequency (and/or frequency band) at which the PLL  215  is locked. Controller  230 , using for example the state machine  231 , controls the PLL  215  to alternate between a first frequency (f 1 ) and a second frequency (f 2 ). Additionally, the controller  230 , using for example the state machine  231 , controls the PLL  215  to stop alternating between the first frequency and the second frequency such that the PLL  215  operates at a selected one of the first frequency or second frequency. 
     According to some embodiments, the detector  233  detects at least a portion (e.g., a beginning or a part of the beginning) of a preamble from the signal  220  and determines whether the detected portion of the preamble corresponds to a desired signal. In some examples, the captured portion of the preamble used in the determination is part of the preamble, not the whole preamble from the signal  220 . In these examples, the detector  233  is configured to determine whether the detected portion of the preamble corresponds to the desired signal before receiving and/or capturing the remainder of the preamble and/or before receiving and/or capturing the remainder of a message associated with the preamble. Although some of the embodiments of this disclosure are discussed with respect to the beginning or a part of the beginning of the preamble, the embodiments of this disclosure are not limited to these examples and any portion of the preamble from signal  220  (e.g., the beginning, part of the beginning, or beyond) can be detected and used by the detector  233 , without capturing the remainder or all of the preamble. 
     According to some embodiments, a desired signal includes a signal that is destined to the device that includes the system  200 . For example, the desired signal can include an identifier (ID) (e.g., an address) associated with the device. If the detector  233  determines that the detected beginning or part of the beginning of the preamble corresponds to the desired signal (e.g., the received input signal includes an identifier of the device that includes the system  200 ), the controller  230  (using for example the state machine  231 ) can control PLL  215  to stop alternating between the first frequency and the second frequency. Further, the controller  230  informs the data acquisition circuitry  250  that the detected beginning or part of the beginning of the preamble appears to correspond to the desired signal and instructs the data acquisition circuitry  250  to detect the preamble of the signal  220 . Since controller  230  operates on at least part of the beginning of the preamble (e.g., beginning or part of the beginning of the preamble), determining whether the received input signal includes the identifier associated with device using the detected at least part of the beginning of the preamble may result in incorrect detections in some cases. Therefore, the data acquisition circuitry  250  can further perform the determination whether the received input signal includes the identifier associated with device using the detected preamble at the data acquisition circuitry  250 , according to some embodiments. 
     An exemplary operation of the system  200  is discussed in more detail below. It is noted that this discussion is an exemplary operation and the embodiments of this disclosure are not limited to this example. In this example, the PLL  215  operates at the first frequency. Digital signal  220 , which is output from the transceiver  210 , is input to the controller  230 . According to some examples, the signal  220  is input to the digital muting masks  235 A and  235 B. Digital muting mask  235  can mask the received signal having a frequency different than the selected frequency of the digital muting mask. For example, the digital muting mask  235 A is designed for the first frequency and the digital muting mask  235 B is designed for the second frequency. In some embodiments, the digital muting masks  235 A and  235 B are respective digital notch filters having respective passbands tuned the respective first and second frequencies. In some embodiments, any number of digital muting masks can be included. Signal  220  that is generated from the input signal when the PLL  215  operates at the first frequency will be masked by digital muting mask  235 B so that the detector  233 B (which is designed for the second frequency) does not make any detection. However, the digital muting mask  235 A passes the signal  220  that is generated from the input signal when the PLL  215  operates at the first frequency to the detector  233 A. According to some embodiments, the detector  233 A detects a beginning or a part of the beginning of a preamble of signal  220  and determines whether the detected beginning or part of the beginning of the preamble corresponds to a desired signal. If the detector  233 A determines that the detected beginning or part of the beginning of the preamble does not correspond to the desired signal, the controller  230  (using for example the state machine  231 ) controls the PLL  215  to switch to the second frequency. 
     Continuing with this example, the PLL  215  operates at the second frequency. Digital signal  220 , which is the output from the transceiver  210 , is input to the controller  231 . According to some examples, the signal  220  is input to the digital muting masks  235 A and  235 B. Signal  220  that is generated from the input signal when the PLL  215  operates at the second frequency will be masked by the digital muting mask  235 A so that the detector  233 A (which is designed for the first frequency) does not make any detection. However, the digital muting mask  235 B passes the signal  220  that is generated from the input signal when the PLL  215  operates at the second frequency to the detector  233 B. According to some embodiments, the detector  233 B detects a portion (e.g., a beginning or a part of the beginning) of a preamble of the signal  220  and determines whether the detected portion of the preamble corresponds to a desired signal. If the detector  233 B determines that the detected beginning or part of the beginning of the preamble does not correspond to the desired signal, the controller  230  (using for example the state machine  231 ) controls the PLL  215  to switch to the first frequency. 
     In some embodiments, this process can continue until, for example, one of the detectors determines that the detected beginning or part of the beginning of the preamble corresponds to the desired signal. As one example, the detector  233 A, before capturing the remainder portion of the preamble, determines that the detected beginning or part of the beginning of the preamble of the signal  220  corresponds to the desired signal. In this case, the controller  230  (using for example the state machine  231 ) controls the PLL  215  to stop alternating between the first frequency and the second frequency, and uses the first frequency. Then, the controller  230  informs the data acquisition circuitry  250  that the detected beginning or part of the beginning of the preamble corresponds to the desired signal and instructs the data acquisition circuitry  250  to detect the preamble of the signal  220 . 
     According to some embodiments, the data acquisition circuitry  250  can include one or more correlators  251 A and  251 B (collectively referred to as correlators  251 .) Data acquisition circuitry  250  can optionally include one or more digital muting masks  253 A and  253 B (collectively referred to as digital muting masks  253 ). Upon receiving the instructions  240  from the controller  230 , the data acquisition circuitry  250  can detect the remainder portion of the preamble from signal  220 . Continuing with the example above, the controller  230  informs the data acquisition circuitry  250  that the detected beginning or part of the beginning of the preamble appears to correspond to the desired signal. Controller  230  can use the signal  240  to communicate with the data acquisition circuitry  250 . Controller  230  can also instruct the data acquisition circuitry  250  that the desired signal is associated with the first frequency (in this example.) Based on the received signal  240 , the data acquisition circuitry  250  uses the correlator  251 A (which is associated with the first frequency) to detect and capture the remainder portion of the preamble or part of the preamble from signal  220 . Digital muting mask  253  operates in a similar manner to digital muting mask  235  of controller  230  discussed above. 
     The data acquisition circuitry  250  using the correlator  251  compares the captured remainder portion of the preamble with the desired signal. If the data acquisition circuitry  250  and the correlator  251  determine that the captured remainder portion of the preamble does not correspond to the desired signal, the data acquisition circuitry  250  can infoun the controller  230  that the received signal does not correspond to the desired signal. The data acquisition circuitry  250  can use signal  241  to communicate with the controller  230 , according to some embodiments. In response, the controller  230  can instruct the state machine  231  to switch to the next frequency. This process can continue until, for example, one of the detectors  233  of the controller  230  determines that a detected beginning or part of the beginning of the preamble corresponds to the desired signal. If the data acquisition circuitry  250  and the correlator  251  determine that the captured remainder portion of the preamble corresponds to the desired signal, the data acquisition circuitry  250 , using the correlator  251 , can capture the rest of the received signal (e.g., the payload associated with the received signal) and use the data and information within the preamble and the payload for establishing a connection with the second device. 
     According to some examples, system  200  can substantially simultaneously scan two frequencies (f 1  and f 2 ) using one transceiver  210 , e.g., based on the procedure discussed above. It is noted that although two frequencies are illustrated and are discussed with respect to  FIG. 2 , the embodiments of this disclosure can be extended to three or more frequencies scanned using one receiver. 
     According to some examples, detector  233  can include correlators configured to correlate an input signal to a reference signal. In some embodiments, the detector  233  can include IQ correlators, where I is the in-phase component of a waveform and Q is the quadrature component of the waveform. Additionally or alternatively, the detector  233  can include correlators that operate on a radius and an angle (RO) of received signals. For example, the detector  233  can include a correlator that transforms a received complex signal (IQ signal) to the radius and angle (RO), and uses the radius and the angle for correlation with the reference signal. It is noted these detectors and correlators are provided as examples for the detector  233 , but the embodiments of this disclosure are not limited to these examples. 
     According to some examples, the detector  233  and/or the digital muting mask  235  can also include one or more sliders. The one or more sliders are used to slide through the reference signal to compare it to the received beginning or part of the beginning of the preamble. By sliding through the reference signal and comparing it with the received beginning or part of the beginning of the preamble, the detector  233  can determine whether the received beginning or part of the beginning of the preamble matches part of the reference signal. 
       FIG. 3  is a functional block diagram depicting an example system implementing a detector, according to some embodiments of the disclosure. The detector  300  of  FIG. 3  can be implemented as or within one or more detectors  233  of  FIG. 2 . The detector  300  of  FIG. 3  is one exemplary implementation of the detector  233 . Detector  233  of  FIG. 2  can be implemented using other components. According to some examples, detector  300  can be a scan early detector. 
     According to some examples, the detector  300  includes a digital muting mask  335 . The digital muting mask  335  can be similar to the digital muting mask  235  (and  253 ) discussed earlier. In some examples, the digital muting mask  335  can be part of the detector  300 . Additionally or alternatively, the digital muting mask  335  can be outside of the detector  300 . The digital muting mask  335  can mask a received signal having a frequency different than a selected frequency of the digital muting mask. 
     As illustrated in  FIG. 3 , a signal  330  is input to the digital muting mask  335 . The input signal  330  can be the digital signal  220  of  FIG. 2 . The output  332  of the digital muting mask  335  is input to a differentiator circuit  301 . The differentiator circuit  301  is configured to generate a derivative of the signal  332 . The differentiator circuit  301  may be implemented using, for example, an active differentiator circuit, a passive differentiator circuit, or other differentiator circuit. Signal  334 , which is output of the differentiator circuit  301 , is input to angle calculator circuit  303 . According to some examples, the angle calculator circuit  303  is configured to determine an angle of the signal  334  and output signal  336 . For example, the angle calculator circuit  303  can determine the angle of the signal  334  by taking an arctangent of the signal  334 . 
     Similar operations are performed on a reference signal  305  (e.g., an access code.) According to some embodiments, the detector  300  is configured to determine whether the input signal  330  matches fully and/or partially the reference signal  305 . As depicted in  FIG. 3 , reference signal  305  is input to the differentiator circuit  307 . Signal  338 , which is output of the differentiator circuit  307 , is input to the angle calculator circuit  309 . According to some examples, the angle calculator circuit  309  is configured to determine an angle of the signal  338  and output signal  340 . For example, the angle calculator circuit  309  can determine the angle of the signal  338  by taking the arctangent of the signal  338 . 
     Signals  336  and  340  are input to the adder circuit  311 . In some examples, the adder circuit  311  is configured to determine the difference between signals  336  and  340 . The difference signal  342  is input to the mean calculator circuit  313  and the standard deviation calculator circuit  315 . The mean calculator circuit  313  is configured to receive the difference signal  342  and to determine the average of this signal. The signal  344 , the output of the mean calculator circuit  315 , is a frequency offset between the input signal  330  and the reference signal  305 , according to some embodiments. 
     The signal  344  (e.g., the frequency offset between the input signal  330  and the reference signal  305 ) can be compared with a threshold at the comparator circuit  317 . If the signal  344  is more that the threshold, the detector  300  determines that the input signal  330  and the reference signal  305  do not match. If during the operation of the comparator circuit  317  it is determined that the signal  344  is less than or equal to the threshold, then comparator circuit  317  can output the signal  344  as the signal  346  to the multiplier circuit  323 . In some examples, the threshold can be around 100 kHz. However, the embodiments of this disclosure are not limited to this threshold and other values can be used. 
     Similarly, the difference signal  342  is input to the standard deviation calculator circuit  315 , where the standard deviation of the difference signal  342  is calculated as signal  348 . A constant value  319  is subtracted from the signal  348 , by the adder circuit  321 . In some examples, the value of the constant  319  can be around 1. However, the embodiments of this disclosure are not limited to this value and other constant values can be used. 
     Signal  352 , which is the difference between the signal  348  and the constant value  319 , is an input to the multiplier circuit  323 . The signal  346  is also input to the multiplier circuit  323 . Signal  354 , the output of multiplier  323 , is compared with a threshold at comparator  325 . If the signal  354  is greater than the threshold, the detector  300  determines that the input signal  330  matches the reference signal  305 . However, if the signal  354  is less than or equal to the threshold, the detector  300  determines that there is not a match between the input signal  330  and the reference signal  305 . 
       FIG. 4A  is a diagram depicting an example timing diagram  400  for scanning by a device such as device  104   1  of  FIG. 1A , according to some embodiments of the disclosure. The timing diagram  400  can include a first portion  401 , a second portion  403 , a third portion  405 , a fourth portion  407 , etc. 
     In some of the embodiments of this disclosure and referring back to  FIG. 1A , the device  104   1  may substantially simultaneously scan two or more frequencies using only one transceiver. For example, the device  104   1  substantially simultaneously scans two or more frequencies based on the timing diagram  400 . The device  104   1  substantially simultaneously scans a channel associated with a frequency from a first set of frequencies and a channel associated with a frequency from a second set of frequencies. The portion  401  of the timing diagram  400  can be used for scanning a channel associated with a first frequency from a first set of frequencies associated with connection establishment according to the Bluetooth™ protocol. The portion  403  of the timing diagram  400  can be used for scanning a channel associated with a second frequency from a second set of frequencies associated with connection establishment according to the Bluetooth™ protocol. According to some examples, the first set of frequencies is different and separate from the second set of frequencies. In some other examples, the first and second sets of frequencies can overlap by any degree. 
     The portion  405  of the timing diagram  400  can be used for scanning a channel associated with a third frequency from the first set of frequencies associated with the Bluetooth™ connection. In some examples, the first and the third frequencies of the first set of frequencies in portions  401  and  405  can be the same. Alternatively, the first and the third frequencies of the first set of frequencies in portions  401  and  405  can be different frequencies within the first set of frequencies. 
     The portion  407  of the timing diagram  400  can be used for scanning a channel associated with a fourth frequency from the second set of frequencies associated with connection establishment according to the Bluetooth™ protocol. In some examples, the second and the fourth frequencies of the second set of frequencies in portions  403  and  407  can be the same. Alternatively, the second and the fourth frequencies of the second set of frequencies in portions  403  and  407  can be different frequencies within the second set of frequencies. In some examples, the portions  401 ,  403 ,  405 , and  407  can be approximately 25 vs to 35 vs (e.g., approximately 32 vs) long. However, the embodiments of this disclosure are not limited to these examples. 
     In this example, the scanning of the first and second sets of frequencies are multiplexed in time. In other words, different time slots are used for portions  401 ,  403 ,  405 , and  407 . According to some embodiments, as illustrated in for example  FIG. 4C , two or more of the portions  401 ,  403 ,  405 , and  407  are within one page scan window (e.g., one page scan window  128 A of  FIG. 1B  during the initial connection and pairing and/or one page scan window during further connections after the initial connection and pairing.) For example, the duration of the page scan window can be divided in two or more sections, each section including one of the portions  401 ,  403 ,  405 , or  407 . 
       FIG. 4B  is a diagram depicting an example timing diagram  410  for scanning by a device such as device  104   1  of  FIG. 1A , according to some embodiments of the disclosure. The timing diagram  410  can include a first portion  411 , a second portion  413 , a third portion  415 , a fourth portion  417 , a fifth portion  419 , etc. 
     In some of the embodiments of this disclosure and referring back to  FIG. 1A , the device  104   1  may substantially simultaneously scan two or more frequencies using only one transceiver. For example, the device  104   1  can substantially simultaneously scan two or more frequencies based on the timing diagram  410 . The device  104   1  substantially simultaneously scans a channel associated with a frequency from a first set of frequencies and a channel associated with a frequency from a second set of frequencies. The portion  411  of the timing diagram  410  can be used for scanning a channel associated with a first frequency from a first set of frequencies associated with connection establishment according to the Bluetooth™ Low Energy protocol. The portion  413  of the timing diagram  410  can be used for scanning a channel associated with a second frequency from a second set of frequencies associated with connection establishment according to the Bluetooth™ protocol. According to some examples, the first set of frequencies is different and separate from the second set of frequencies. 
     The portion  415  of the timing diagram  410  can be used for scantling a channel associated with a third frequency from the first set of frequencies associated with connection establishment according to the Bluetooth™ Low Energy protocol. In some examples, the first and the third frequencies of the first set of frequencies in portions  411  and  415  can be the same. Alternatively, the first and the third frequencies of the first set of frequencies in portions  411  and  415  can be different frequencies within the first set of frequencies. The portion  417  of the timing diagram  410  can be used for scanning a channel associated with a fourth frequency from the second set of frequencies associated with connection establishment according to the Bluetooth™ protocol. In some examples, the second and the fourth frequencies of the second set of frequencies in portions  413  and  417  can be the same. Alternatively, the second and the fourth frequencies of the second set of frequencies in portions  413  and  417  can be different frequencies within the second set of frequencies. In some examples, the portions  411 ,  415 , and  419  can be approximately 25 μs to 35 μs (e.g., approximately 32 μs) long and portions  413  and  417  can be approximately 25 μs to 35 μs (e.g., approximately 32 μs) long. However, the embodiments of this disclosure are not limited to these examples. 
     In this example, the scanning of the first and second sets of frequencies are multiplexed in time. In other words, different time slots are used for portions  411 ,  413 ,  415 ,  417 , and  419 . According to some embodiments, two or more of the portions  411 ,  413 ,  415 ,  417 , and  419  are within one page scan window (e.g., one page scan window  128 A of  FIG. 1B  during the initial connection and pairing and/or one page scan window during further connections after the initial connection and pairing.) For example, the duration of the page scan window can be divided in two or more sections, each section including one of the portions  411 ,  413 ,  415 ,  417 , and  419 . 
     It is noted that the scan signal, sets of frequencies, and their combination are provided for example purposes only, and do not limit the embodiments of this disclosure. Based on the disclosure herein, a person of ordinary skill in art will understand that other sets and other combinations can exist. 
     According to some embodiments, the disclosed methods and systems allow a device to substantially simultaneously scan two or more frequencies using one receiver. For example, the controller  230 , in operation with the transceiver  210  and the data acquisition circuitry  250 , allows the devices, such as the device  104   1 , to substantially simultaneously scan two or more frequencies using one transceiver  210 . Although the device  104   1  is using one transceiver  201 , from the point of view of the medium access control (MAC) layer of the device  104   1 , it appears that the device  104   1  has two or more receivers. 
     These embodiments can reduce (improve) the time it takes for establishing the connection  106   8  between the devices  104   1  and  104   8 . For example, in some circumstances, the connection time can be reduced by a factor of 2-3. Depending on the implementation of the embodiments of this disclosure and, for example, the number of frequencies to be scanned substantially simultaneously, the improvement factor corresponding to the connection time can be higher. Further, compared to conventional methods and systems, by reducing the connection time, the periodicity of scanning by the device can be increased while keeping the power consumption of the device unchanged, according to some embodiments. 
     Additionally or alternatively, the embodiments of this disclosure can reduce (improve) the battery consumption (e.g., increase battery life) of the device  104   1  for scanning and establishing the connection  106   8  between the devices  104   1  and  104   8 . For example, the battery consumption can be reduced by a factor of 2-3. Depending on the implementation of the embodiments of this disclosure and, for example, the number of frequencies to be scanned substantially simultaneously, the improvement factor corresponding to the battery consumption can be higher. Further, compared to conventional methods and systems, by reducing the connection time, the battery consumption can be reduced while keeping the periodicity of scanning by the device unchanged, according to some embodiments. 
       FIG. 5A  is a functional block diagram depicting another example system implementing the scan method, according to some embodiments of the disclosure. System  500  of  FIG. 5A  can be implemented within one or more devices of  FIG. 1A . System  500  may include a transceiver  510 , a controller  530 , and data acquisition circuitry  550 . It is noted that the transceiver  510 , the controller  530 , and the data acquisition circuitry  550  are depicted as exemplary components of the system  500 , and the system  500  can include other components. 
     As illustrated in the example of  FIG. 5 , the transceiver  510  may include an antenna  512 , an amplifier  511 , mixers  513   a  and  513   b , phase-locked loops (PLL)  515   a  and  515   b , filters  517   a  and  517   b , converters  519   a  and  519   b , and a multiplexer  560 , according to some embodiments. In some examples, the amplifier  511  can include, but is not limited to, a low noise amplifier (LNA). The converters  519   a  and  519   b  can also include, but are not limited to, an analog to digital converter. According to some embodiments, the transceiver  510  may be configured to receive an input signal using, for example, the antenna  512  that is communicatively coupled to the amplifier  511 . The received input signal may be amplified by the amplifier  511 . The amplified signal may then be mixed, using the mixers  513   a  and/or  513   b , with a signal from multiplexer  560 . 
     The multiplexer  560  is controlled to output the output of PLL  515   a  or the output of PLL  515   b . According to some embodiments, the multiplexer  560  can be controlled by the controller  530  such that the output signal of the multiplexer  560  includes a selected frequency and/or a selected frequency band. The amplified received input signal (e.g., an amplified radio frequency (RF) signal) and the output signal of the multiplexer  560  are input to the mixers  513   a  and/or  513   b . According to some embodiments, the mixers  513   a  and/or  513   b , using the output signal of the multiplexer  560 , are configured to downconvert the amplified received input signal. Therefore, the output of the mixers  513   a  and/or  513   b  includes a baseband signal or an intermediate frequency (IF) signal, according to some embodiments. 
     The mixed signal outputs of mixers  513   a  and  513   b  can pass through the corresponding filters  517   a  and  517   b . The filters  517   a  and  517   b  can include a low pass filter, a bandpass filter, and/or other filters. The filtered signal can be converted from analog to digital using the corresponding converters  519   a  and  519   b  to generate digital signals. The digital signals are then fed to the controller  530  and the data acquisition circuitry  550 . According to the exemplary embodiments of  FIG. 5A , the transceiver  510  may include an IQ transceiver, where I is the in-phase component of a waveform and Q is the quadrature component of the waveform. It is noted that the components of the transceiver  510  discussed above are exemplary circuits and/or modules, and transceiver  510  can include different, fewer, or additional circuits/modules. 
     According to some embodiments, the controller  530  can control the multiplexer  560  of the transceiver  510  to select between the PLL  515   a  and the PLL  515   b . Additionally or alternatively, the controller  530  can configure the frequencies at which the PLLs  515   a  and  515   b  operate. For example, the controller  530  sets the PLL  515   a  to operate at a first frequency and sets the PLL  515   b  to operate a second frequency. Then, controller  530  controls the multiplexer  560  to switch between the first and second frequencies for the respective PLLs. In some embodiments, the controller  530  can be configured to change the frequencies at which the PLLs operate. For example, the controller  530  can set the PLL  515   a  to operate at the first frequency, but set the PLL  515   b  to operate a third frequency, different from the first frequency. 
     The operation of the controller  530  is similar to the controller  230  discussed above with respect to  FIG. 2 . The controller  530  can include one or more IQ correlators that would operate on the in-phase component and the quadrature component received from the transceiver  510 . In addition to controlling the multiplexer  560  and/or the PLLs  515   a  and  515   b , the controller  530  informs the data acquisition circuitry  550  that a detected beginning or part of the beginning of the preamble corresponds to a desired signal and instructs the data acquisition circuitry  550  to detect the preamble of the signal received from the transceiver  510 . The operation of the data acquisition circuitry  550  is similar to the data acquisition  250  discussed above with respect to  FIG. 2 . The data acquisition circuitry  550  can include one or more IQ correlators that would operate on the in-phase component and/or the quadrature component received from transceiver  510 . 
       FIG. 5B  is a diagram depicting an example timing  587  for scanning by the transceiver  510  of, for example, the device  104   1  of  FIG. 1A , according to some embodiments of the disclosure.  FIG. 5B  also illustrates the timing of the frequencies generated by the PLLs. For example, timing diagram  581  illustrates the frequency generated by the PLL  515   a . In this example, the PLL  515   a  generates a first frequency (f 1 ). Similarly, the timing diagram  583  illustrates the frequency generated by the PLL  515   b . In this example, the PLL  515   b  generates a second frequency (f 2 ). As discussed above, controller  530  can control the PLLs and their frequencies. 
       FIG. 5B  further illustrates timing diagram  587  of the frequencies scanned by transceiver  510 . The timing diagram  587  illustrates that the frequencies scanned by transceiver  510  are toggled between the first frequency (f 1 ) and the second frequency (f 2 ). In this example, to achieve the timing diagram  587 , the controller  530  may control the multiplexer  560  to select the PLLs as follows: PLL  515   a , PLL  515   b , PLL  515   a , PLL  515   b  . . . . It is noted that these timing diagrams, sets of frequencies, and their combination are provided for example purposes only, and do not limit the embodiments of this disclosure. Based on the disclosure herein, a person of ordinary skill in art will understand that other sets and other combinations of frequencies can be utilized within the scope and spirit of the present disclosure. 
     In this example, the scanning of the first and second sets of frequencies are multiplexed in time. In other words, different time slots are used for portions of timing diagram  587 . According to some embodiments, two or more of the portions of timing diagram  587  are within one page scan window (e.g., one page scan window  128 A of  FIG. 1B  during the initial connection and pairing, and/or one page scan window during further connections after the initial connection and pairing.) For example, the duration of the page scan window can be divided in two or more sections, each section including one of the portions of timing diagram  587 . 
     According to some examples, if a device such as device  104   1  includes two transceivers (e.g., in a multiple input multiple output (MIMO) device), the methods and apparatuses discussed above can be implemented in one or both of the transceivers. Accordingly, up to four frequencies can be scanned substantially simultaneously using the two transceivers. According to some examples, systems  200  and/or  500  can be used in each of the transceivers. For example, each of the two transceivers can use the system  200 , where a first PLL would toggle between a first frequency and a second frequency, and a second PLL would toggle between a third frequency and a fourth frequency. In another example, each of the two transceivers can use the system  500 , where a first multiplexer chooses between a first PLL at a first frequency and a second PLL at a second frequency, and a second multiplexer chooses between a third PLL at a third frequency and a fourth PLL at a fourth frequency. 
     Alternatively,  FIG. 6A  is a functional block diagram depicting another example system implementing the scan method for scanning between four frequencies, according to some embodiments of the disclosure. System  600  of  FIG. 6A  can be implemented within one or more devices of  FIG. 1A . System  600  may include two transceivers (e.g., transceivers  610  and  640 ), two controllers (e.g., controllers  630  and  670 ), and two data acquisition circuitries (e.g., data acquisition circuitries  650  and  680 .) It is noted that the transceivers  610  and  640 , the controllers  630  and  670 , and the data acquisition circuitries  650  and  680  are depicted as exemplary components of system  600 , and system  600  can include other components. Further, the transceivers  610  and  640 , the controllers  630  and  670 , and the data acquisition circuitries  650  and  680  are similar in operation and/or implementation respectively to the transceiver  510 , the controller  530 , and the data acquisition circuitry  550 , discussed above with respect to  FIG. 5 . Accordingly, differences are discussed here for brevity. 
     One difference between the transceivers  610  and  640  of system  600  and the transceiver  510  of system  500  is that the transceivers  610  and  640  can include three PLLs and the multiplexers  660  and  662  select the outputs of one of the three PLLs. According to some examples, the three PLLs can be shared between the transceivers  610  and  640 , as depicted in  FIG. 6A . Additionally or alternatively, one or more of the PLLs can be dedicated to its respective transceiver. As discussed above with respect to  FIG. 5 , controllers  630  and  670  may control the multiplexers  660  and  662  and/or the frequencies of the PLLs. 
     It is noted that although controllers  630  and  670  are depicted as separate controllers in  FIG. 6A , system  600  can include one controller configured to detect the beginning or part of the beginning of the preambles of signals received by the transceivers  610  and  640 . The one controller can also control the PLLs and the multiplexers associated with the transceivers  610  and  640 . Similarly, although data acquisition circuitries  650  and  680  are depicted as separate data acquisition circuitries, system  600  can include one data acquisition circuit configured to detect the preamble and/or payload of signals received by the transceivers  610  and  640 . 
       FIG. 6B  is a diagram depicting example timing diagrams  687  and  689  for scanning by two transceivers of, for example, the device  104   1  of  FIG. 1A , according to some embodiments of the disclosure. 
       FIG. 6B  also illustrates the timing diagrams of the frequencies generated by the PLL. For example, the timing diagram  681  illustrates the frequencies generated by PLL  615   a . In this example, PLL  615   a  generates a third frequency (f 3 ) for a period of time. Then PLL  615   a  transitions from the third frequency (f 3 ) to a second frequency (f 2 ). PLL  615   a  generates the second frequency (f 2 ) for a period of time. PLL  615   a  then transitions from the second frequency (f 2 ) to a fourth frequency (f 4 ). PLL  615   a  generates the fourth frequency (f 4 ) for a period of time. PLL  615   a  then transitions from the fourth frequency (f 4 ) to a first frequency (f 1 ). PLL  615   a  generates the first frequency (f 1 ) for a period of time. Then PLL  615   a  transitions to the third frequency (f 3 ). These changes in the frequency generated by the PLL  615   a  can repeat or vary in any pattern. 
     Similarly, timing diagram  683  illustrates the frequencies generated by PLL  615   b  of the transceiver  610  (and/or PLL  615   b  of the transceiver  710 .) In this example, PLL  615   b  generates a first frequency (f 1 ) for a period of time. Then PLL  615   b  transitions from the first frequency (f 1 ) to a third frequency (f 3 ). PLL  615   b  generates the third frequency (f 3 ) for a period of time. PLL  615   b  then transitions from the third frequency (f 3 ) to a second frequency (f 2 ). PLL  615   b  generates the second frequency (f 2 ) for a period of time. PLL  615   b  then transitions from the second frequency (f 2 ) to a fourth frequency (f 4 ). PLL  615   b  generates the fourth frequency (f 4 ) for a period of time. Then PLL  615   b  transitions to the first frequency (f 1 ). These changes in the frequency generated by the PLL  615   b  can repeat or vary in any pattern. 
     Similarly, timing diagram  685  illustrates the frequencies generated by PLL  615   c  of the transceiver  610  (and/or PLL  615   c  of the transceiver  710 .) In this example, PLL  615   c  generates a fourth frequency (f 4 ) for a period of time. Then PLL  615   c  transitions from the fourth frequency (f 4 ) to a first frequency (f 1 ). PLL  615   c  generates the first frequency (f 1 ) fora period of time. PLL  615   c  then transitions from the first frequency (f 1 ) to a third frequency (f 3 ). PLL  615   c  generates the third frequency (f 3 ) for a period of time. PLL  615   c  then transitions from the third frequency (f 3 ) to a second frequency (f 2 ). PLL  615   c  generates the second frequency (f 2 ) for a period of time. Then PLL  615   c  transitions to the fourth frequency (f 4 ). These changes in the frequency generated by the PLL  615   c  can repeat or vary in any pattern. 
     As discussed above, controllers  630  and/or  670  can control the PLLs and their frequencies. 
       FIG. 6B  further illustrates timing diagram  687  of the frequencies scanned by transceiver  610  and timing diagram  689  of the frequencies scanned by transceiver  710 . As shown by the timing diagram  687 , the frequencies scanned by transceiver  610  are toggled between the first frequency (f 1 ) and the second frequency (f 2 ). Also, as shown by the timing diagram  689 , the frequencies scanned by transceiver  710  are toggled between the third frequency (f 3 ) and the fourth frequency (f 4 ). In this example, to achieve the timing diagram  687 , the controller  630  may control multiplexer  660  to select the PLLs as follows: PLL  615   b , PLL  615   a , PLL  615   c , PLL  615   b , PLL  615   a , PLL  615   c , etc. Also, to achieve the timing diagram  689 , the controller  670  may control multiplexer  662  to select the PLLs as follows: PLL  615   c , PLL  615   b , PLL  615   a , PLL  615   c , PLL  615   b , PLL  615   a , etc. 
     It is noted that these timing diagrams, sets of frequencies, and their combination are provided as examples, and do not limit the embodiments of this disclosure. Based on the disclosure herein, a person of ordinary skill in art will understand that other sets of frequencies and other combinations can exist. 
       FIG. 7  is a flowchart depicting an example method  700  for substantially simultaneously scanning two or more frequencies using one receiver, according to some embodiments. For convenience,  FIG. 7  will be described with references to  FIGS. 1 and 2 , but method  700  is not limited to the specific embodiments depicted in those figures. 
     Method  700  begins at  702  when a first device, for example the device  104   1 , receives a signal from a second device, such as the device  104   8 . The signal that the device  104   1  receives can include one or more pages from the device  104   8 . The device  104   1  may amplify the received signal, mix the amplified signal with a signal from a PLL, filter the mixed signal, and covert the filtered signal to a digital signal for further processing. In this example, the PLL is configured to operate at a first frequency (f 1 ). 
     As discussed above with respect to  FIG. 2 , the first device can include the transceiver  210 , the controller  230 , and the data acquisition circuitry  250 . Before receiving the signal from the second device, the controller  230  configures the transceiver  210  to operate at a first frequency. For example, the controller  230 , which is communicatively coupled to the transceiver  210 , using the state machine  231 , controls the PLL  215  of the transceiver  210  to operate at the first frequency. After the transceiver  210  of the first device receives the signal from the second device, and optionally performs some further operation on the signal, the transceiver  210  sends the received signal to the controller  230  for further detection. 
     At  704 , the device  104   1  captures at least a portion (e.g., a beginning or a part of the beginning) of a preamble from the received signal. For example, digital muting mask  235  and detector  233  are configured to capture the beginning or the part of the beginning of the preamble. According to some examples, and as discussed with respect to  FIG. 3 , capturing the beginning or the part of the beginning of the preamble of the received signal can include digital mute masking of the received signal such that the received signal will be muted (e.g., the received signal is equaled to zero) if the frequency of the operation of the detector  233  is different from the frequency of the operation of the PLL  215 . The capturing further can include determining a derivate of the received signal and an angle for the determined derivate of the signal. Additionally, the capturing can include determining a derivate of a reference signal (e.g., an access code) and an angle for the determined derivate of the reference signal. These operations are provided as examples for capturing the beginning or the part of the beginning of the preamble. However, the capturing can include other operations as understood by a person of ordinary skill in the art. 
     At  706 , the device  104   1  determines, based at least in part on the captured portion (e.g., the beginning or part of the beginning) of the preamble and before receiving and/or capturing the remainder of the preamble, whether the received signal is intended for the device  104   1 . For example, the controller  230 , using the detector  233 , is configured to determine whether the received digital signal is intended for the device  104   1 . In some embodiments, and as discussed with respect to  FIG. 3 , this detection can include comparing one or more calculated angles of the received signal and the reference signal, using a difference between the calculated angles to calculate the mean and/or the standard deviation of the difference, and comparing the calculated mean and/or standard deviation with one or more thresholds. These operations are provided as examples for determining whether the received signal is intended for the device  104   1 . However, the determining can include other operations as understood by a person of ordinary skill in the art. In some embodiments, the determination in  706  can have a high false-alarm rate. Therefore, method  700  can include a further determination in  714  to make sure that the received signal is intended for the device  104   1 , according to some embodiment. The determination in  714  can have a lower false-alarm rate. 
     If the received signal is not intended for the device  104   1 , the device  104   1 , using for example the controller  230  and the state machine  231 , controls the PLL of the device  104   1  at  708  to operate at a second frequency (f 2 ). For example, the controller  230  using the state machine  231  sends an instruction to PLL  215  of the transceiver  210  to operate at the second frequency. According to some examples, the state machine  231  periodically switches between the first frequency and the second frequency. Each time the state machine  231  switches from one frequency to another, an instruction is sent by the controller  230  to the PLL  215  to change the frequency of the operation of the PLL  215  of the transceiver  210 . 
     In some embodiments, the periodically switching includes periodically switching between the first frequency of the first set of plurality of frequencies and the second frequency of the second set of plurality of frequencies during a page scan window of the first device. According to some examples, the state machine  231  is configured to switch between the first frequency and the second frequency with a frequency of, for example, approximately 2.5 KHz to approximately 200 KHz during a page scan window associated with the first device, according to some examples. For example, the PLL  215  can operate at the first frequency for approximately 25 μs to 35 μs (e.g., for approximately 32 μs) before switching to the second frequency (if the received signal at the first frequency is not intended for the device  104   1 ). In this example, then the PLL  215  can operate at the second frequency for approximately 25 μs to 35 μs (e.g., for approximately 32 μs) before switching back to the first frequency (if the received signal at the second frequency is not intended for the device  104   1 ). In another example, the PLL  215  can operate at the first frequency for approximately 25 μs to 35 μs (e.g., for approximately 32 μs) before switching to the second frequency (if the received signal is not intended for the device  104   1 ). In this example, then the PLL  215  can operate at the second frequency for approximately 5 μs to 15 μs (e.g., for around 12 μs) before switching to the first frequency (if the received signal is not intended for the device  104   1 ). In some examples, when at  706 , the device  104   1  determines that the received signal is intended for the device  104   1 , the PLL  215  operates at that specific determined frequency for approximately additional tens of microseconds (e.g., approximately 10 μs to 60 μs) before the device  104   1 , at  714 , can determine whether the determination  706  was a false-alarm. 
     According to some embodiments, if the first device (e.g., the device  104   1 ) determines that the received signal is not intended for it, the controller  230  of the first device does not interfere with the operation of the state machine  231 . Therefore, the state machine  231  switches between the frequencies based on its pre-programmed time for switch. Additionally or alternatively, if the first device determines that the received signal is not intended for it, the controller  230  of the first device can instruct the state machine  231  to switch to the next frequency earlier in-time than when the state machine  231  would otherwise have switched. 
     Method  700  continues at  702  and operates using the second frequency (f 2 ). 
     However, if the received digital signal is intended for device  104   1 , the device  104   1 , using for example the controller  230  and the state machine  231 , controls the PLL of the device  104   1  at  710  to continue its operation at the first frequency (f 1 ). In other words, the state machine  231  ceases the switching between the first and second frequencies such that the received signal at the first frequency may be captured and decoded at the device  104   1 . 
     When the device  104   1  determines that the received signal is intended for the device  104   1 , the device  104   1  captures the rest of the preamble (e.g., the remainder portion of the preamble) from the received digital signal at  712 . To capture the rest of the preamble from the received digital signal, the controller  230  of the device  104   1  sends an instruction (e.g., signal  240  of  FIG. 2 ) to the data acquisition circuitry  250  of the device  104   1 , according to some embodiments. This instruction can include a notification to the data acquisition circuitry  250  that the received signal at the device  104   1  appears to be intended for the device  104   1  and a request to the data acquisition circuitry  250  to perform correlation and acquisition of the received signal. This instruction may also include the captured frequency of the received signal (in this example, the first frequency (f 1 )). 
     Data acquisition circuitry  250 , using the correlator  251 , is configured to capture the rest of the preamble of the received digital signal. The correlator  251  can include a detector similar to detector  300  of  FIG. 3 , according to some examples. However, the correlator  251  can include one or more other correlators as known by a person of ordinary skill in the art. According to some examples, the data acquisition circuitry  250 , using the correlator  251 , can capture the rest of the preamble of the received signal and compare the captured portions of the preamble with a reference signal to make sure that the received signal is intended for the first device. At  714 , the data acquisition circuitry  250 , using the correlator  251 , compares the captured preamble with a reference signal to determine whether the received signal is intended for the first device. According to some embodiments, the reference signal used by the data acquisition circuitry  250  and the correlator  251  includes an identifier of the first device. 
     If the data acquisition circuitry  250  and the correlator  251  of the first device determine that the received signal is not intended for the first device, the data acquisition circuitry  250  can inform the controller  230  that the received signal is not intended for the first device. The data acquisition circuitry  250  can use signal  241  to communicate with the controller  230 , according to some embodiments. In response, the controller  230  of the first device can instruct the state machine  231  to switch to the next frequency. Method  700  then continues at  702  and operates using the second frequency (f 2 ). 
     If the data acquisition circuitry  250  and the correlator  251  of the first device determine that the received signal is intended for the first device, method  700  continues at  716  where the data acquisition circuitry  250 , using the correlator  251 , remains at the first frequency (f 1 ) and can receive and capture the rest of the received signal (e.g., the payload associated with the received signal) and use the data and information within the preamble and the payload for establishing a connection with the second device. 
     Based on the data and information within the preamble and the payload of the received signal, the device  104   1  may, for example, establish the connection with the device  104   8 . 
     Various embodiments can be implemented, for example, using one or more well-known computer systems, such as computer system  800  shown in  FIG. 8 . For instance, each of the components and/or operations described with reference to  FIGS. 1-7  could be implemented using one or more computer systems  800  or portions thereof. Computer system  800  can be used, for example, to implement method  700  of  FIG. 7 . For example, computer system  700  can be used for substantially simultaneously scanning two or more frequencies using one receiver, according to some embodiments. The computer system  800  can be any computer capable of performing the functions described herein. 
     The computer system  800  includes one or more processors (also called central processing units, or CPUs), such as a processor  804 . The processor  806  is connected to a communication infrastructure or bus  806 . 
     The processor  806  may be, for example, a graphics processing unit (GPU). In some embodiments, the GPU is a processor that is a specialized electronic circuit designed to process mathematically intensive applications. The GPU may have a parallel structure that is efficient for parallel processing of large blocks of data, such as mathematically intensive data common to computer graphics applications, images, videos, etc. 
     The computer system  800  also includes user input/output/display device(s)  822 , such as monitors, keyboards, pointing devices, etc., that communicate with communication infrastructure  804 . 
     The computer system  800  also includes a main or primary memory  808 , such as random access memory (RAM). The main memory  808  may include one or more levels of cache. The main memory  808  has stored therein control logic  828 A (e.g., computer software) and/or data. 
     The computer system  800  may also include one or more secondary storage devices or memory  810 . The secondary memory  810  may include, for example, a hard disk drive  812  and/or a removable storage device or drive  814 . The removable storage drive  814  may be a floppy disk drive, a magnetic tape drive, a compact disk drive, an optical storage device, tape backup device, and/or any other storage device/drive. 
     The removable storage drive  814  may interact with a removable storage unit  816 . The removable storage unit  818  includes a computer usable or readable storage device having stored therein control logic  828 B (e.g., computer software) and/or data. The removable storage unit  818  may be a floppy disk, magnetic tape, compact disk, DVD, optical storage disk, and/any other computer data storage device. The removable storage drive  814  reads from and/or writes to the removable storage unit  816 . 
     The computer system  800  may further include a communication or network interface  818 . The communication interface  818  enables the computer system  800  to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referenced by reference number  830 ). For example, communication interface  818  may allow the computer system  800  to communicate with remote devices  830  over a communications path  826 , which may be wired and/or wireless, and which may include any combination of LANs, WANs, the Internet, etc. Control logic and/or data may be transmitted to and from computer system  800  via communication path  826 . 
     In some embodiments, a tangible apparatus or article of manufacture including a tangible computer useable or readable medium having control logic (software) stored thereon is also referred to herein as a “computer program product” or “program storage device.” This includes, but is not limited to, the computer system  800 , the main memory  808 , the secondary memory  810 , and the removable storage unit  816 , as well as tangible articles of manufacture embodying any combination of the foregoing. Such control logic, when executed by one or more data processing devices (such as the computer system  800 ), causes such data processing devices to operate as described herein. 
     Based on the teachings contained in this disclosure, it will be apparent to persons skilled in the relevant art(s) how to make and use embodiments of this disclosure using data processing devices, computer systems and/or computer architectures other than that shown in  FIG. 8 . In particular, embodiments may operate with software, hardware, and/or operating system implementations other than those described herein. 
     It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way. 
     The present disclosure has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. 
     The foregoing description of the specific embodiments will so fully reveal the general nature of the disclosure so that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance. 
     References herein to “one embodiment,” “an embodiment,” “an example embodiment,” or similar phrases, indicate that the embodiment described may include a 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. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of persons skilled in the relevant art(s) to incorporate such feature, structure, or characteristic into other embodiments whether or not explicitly mentioned or described herein. 
     The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. 
     The claims in the instant application are different than those of any parent application or other related applications. The Applicant therefore rescinds any disclaimer of claim scope made in the parent application or any predecessor or related application in relation to the instant application. The Examiner is therefore advised that any such previous disclaimer and the cited references that it was made to avoid, may need to be revisited. Further, the Examiner is also reminded that any disclaimer made in the instant application should not be read into or against the parent or related application(s).

Metadata:
Filing Date: 20180710
Publication Date: 20200324
Grant Date: 20200324
Priority Date: 20180710
Inventors: COHEN, MIK
MEIR, SHAHAR
AVNER, YUVAL
Assignee: APPLE INC
CPC Classifications: [{"code": "H03J1/0091", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W8/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03L7/091", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/80", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03L7/091", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03J1/0091", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W8/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W8/005", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 69139273