PATENT DOCUMENT

Publication Number: US-10517111-B2
Application Number: US-201715708746-A
Country: US
Kind Code: B2

Title: Mitigating scheduling conflicts in wireless communication devices

Abstract:
Exemplary embodiments include a method performed by a wireless device configured as a slave in a first piconet and configured as a master in a second piconet. The method includes determining whether the wireless device has data to transmit over the second piconet to an other wireless device, determining an availability of a full slot in a first piconet schedule, selecting a data transmission scheme based on the availability of the full slot in the first piconet schedule and transmitting the data via the second piconet to the other wireless device in accordance with the selected data transmission scheme.

Claims:
What is claimed is: 
     
       1. A method, comprising:
 at a wireless device configured as a slave in a first piconet and configured as a master in a second piconet:
 determining whether the wireless device has data to transmit over the second piconet to an other wireless device; 
 determining an availability of a full slot in a first piconet schedule wherein the full slot is a slot in the first piconet schedule having no scheduled transmissions; 
 selecting a data transmission scheme based on the availability of the full slot in the first piconet schedule; and 
 transmitting the data via the second piconet to the other wireless device in accordance with the selected data transmission scheme. 
 
 
     
     
       2. The method of  claim 1 , wherein determining the availability of the full slot, comprises:
 detecting whether a first portion of a first slot of the first piconet includes a transmission; 
 when there is no transmission detected in the first portion of the first slot, determining that a remainder of the first slot and a next second slot are available, wherein the next second slot comprises the full slot; and 
 when there is a transmission detected in the first portion of the first slot, determining from information included in the transmission whether the remainder of the first slot and the next second slot are available, wherein the next second slot comprises the full slot. 
 
     
     
       3. The method of  claim 2 , wherein transmitting the data via the second piconet when it is determined that the full slot is available, comprises:
 tuning to the second piconet at the end of the first portion of the first slot; and 
 starting the transmitting of the data in the first slot. 
 
     
     
       4. The method of  claim 3 , further comprising:
 switching from a transmission mode to a reception mode after completion of the transmitting of the data, wherein completion occurs during the first slot or the next second slot; 
 receiving further data from the other wireless device via the second piconet; and 
 after completion of receiving the further data, tuning to the first piconet, wherein the tuning to the first piconet is completed prior to an end of the next second slot. 
 
     
     
       5. The method of  claim 1 , wherein, when it is determined that the full slot is not available, the method further comprises:
 determining whether a current slot of the first piconet has available time after completion of communications of the first piconet; and 
 when there is available time in the current slot of the first piconet after completion of communications of the first piconet, determining whether a duration needed for transmitting the data and receiving a response is greater than the available time. 
 
     
     
       6. The method of  claim 5 , wherein determining the duration comprises:
 determining a data length of the data to transmit; 
 determining a link rate of the second piconet; and 
 determining a maximum payload length for the selected data transmission scheme. 
 
     
     
       7. The method of  claim 5 , wherein, when it is determined that the time is not greater than the available time, the transmitting the data comprises:
 tuning to the second piconet at completion of communications of the first piconet in the current slot; 
 transmitting the data in the current slot; 
 switching from a transmission mode to a reception mode after completion of the transmitting of the data; 
 receiving further data from the other wireless device via the second piconet; and 
 after completion of receiving the further data, tuning to the first piconet, wherein the tuning to the first piconet is completed prior to an end of the current slot. 
 
     
     
       8. The method of  claim 5 , wherein, when it is determined that the time is greater than the available time, the transmitting the data comprises:
 tuning to the second piconet at completion of communications of the first piconet in the current slot; 
 transmitting the data in the current slot; and 
 after completion of transmitting the data, tuning to the first piconet, wherein the tuning to the first piconet is completed prior to an end of the current slot. 
 
     
     
       9. The method of  claim 8 , further comprising:
 determining a next slot of the first piconet in which to receive the response to transmitting the data via the second piconet, wherein the next slot is any slot subsequent to the current slot; 
 when the next slot is determined, tuning to the second piconet and selecting a reception mode; 
 receiving further data from the other wireless device via the second piconet; and 
 after completion of receiving the further data, tuning to the first piconet, wherein the tuning to the first piconet is completed prior to an end of the next slot. 
 
     
     
       10. A wireless device capable of communicating via a first piconet and a second piconet, comprising:
 a baseband processor configured to determine whether the wireless device has data to transmit over the second piconet to an other wireless device, determine an availability of a full slot in a first piconet schedule, wherein the full slot is a slot in the first piconet schedule having no scheduled transmissions, and select a data transmission scheme based on the availability of the full slot in the first piconet schedule; and 
 a transceiver configured to transmit the data via the second piconet to the other wireless device in accordance with the selected data transmission scheme. 
 
     
     
       11. The wireless device of  claim 10 , wherein the baseband processor determines the availability of the full slot by receiving information from the transceiver as to whether a transmission was detected in a first portion of a first slot of the first piconet,
 when there is no transmission detected in the first portion of the first slot, the baseband processor determines that a remainder of the first slot and a next second slot are available, wherein the next second slot comprises the full slot, and 
 when there is a transmission detected in the first portion of the first slot, the baseband processor determines from information included in the transmission whether the remainder of the first slot and the next second slot are available, wherein the next second slot comprises the full slot. 
 
     
     
       12. The wireless device of  claim 11 , wherein transmitting the data via the second piconet when it is determined that the full slot is available comprises the transceiver tuning to the second piconet at the end of the first portion of the first slot and starting the transmitting of the data in the first slot. 
     
     
       13. The wireless device of  claim 12 , wherein the transceiver is further configured to switch from a transmission mode to a reception mode after completion of the transmitting of the data, wherein the completion occurs during the first slot or the next second slot, receive further data from the other wireless device via the second piconet and after completion of receiving the further data, tune to the first piconet, wherein the tuning to the first piconet is completed prior to an end of the next second slot. 
     
     
       14. The wireless device of  claim 10 , wherein, when the baseband processor determines that the full slot is not available, the baseband processor determines whether a current slot of the first piconet has available time after completion of communications of the first piconet and when there is available time in the slot of the first piconet after completion of communications of the first piconet, determines whether a time for transmitting the data and receiving a response to transmitting the data is greater than the available time. 
     
     
       15. The wireless device of  claim 14 , wherein the baseband processor determines the time by determining a data length of the data to transmit, determining a link rate of the second piconet, and determining a maximum payload length for the selected data transmission scheme. 
     
     
       16. The wireless device of  claim 14 , wherein, when it is determined that the time is not greater than the available time, the transceiver is further configured to tune to the second piconet at completion of communications of the first piconet in the current slot, transmit the data in the current slot, switch from a transmission mode to a reception mode after completion of the transmitting of the data, receive further data from the other wireless device via the second piconet and after completion of receiving the further data, tune to the first piconet, wherein the tuning to the first piconet is completed prior to an end of the current slot. 
     
     
       17. The method of  claim 14 , wherein, when it is determined that the time is greater than the available time, the transceiver is configured to tune to the second piconet at completion of communications of the first piconet in the current slot, transmit the data in the current slot and after completion of transmitting the data, tune to the first piconet, wherein the tuning to the first piconet is completed prior to an end of the current slot. 
     
     
       18. A wireless device, comprising:
 a non-transitory memory having a program stored thereon; and 
 a processor, wherein execution of the program causes the processor to perfomi operations comprising:
 determining whether the wireless device has data to transmit over the second piconet to an other wireless device; 
 determining an availability of a full slot in a schedule of the first piconet, wherein the full slot is a slot in the first piconet schedule having no scheduled transmissions; 
 selecting a data transmission scheme based on the availability of the full slot in the schedule of the first piconet; and 
 transmitting the data via the second piconet to the other wireless device in accordance with the selected data transmission scheme. 
 
 
     
     
       19. The wireless device of  claim 18 , wherein, when it is determined that the full slot is available, utilizing a full slot transmission scheme where the data is transmitted in the available full slot. 
     
     
       20. The wireless device of  claim 18 , wherein, when it is determined that the full slot is not available, utilizing a partial slot transmission scheme where an available time in a slot of the first piconet is used to transmit the data, wherein the slot is also used to communicate data via the first piconet.

Description:
PRIORITY/INCORPORATION BY REFERENCE 
     This application claims priority to U.S. Provisional Application 62/397,693 entitled “Apparatus, Systems and Methods for Mitigating Scheduling Conflicts in Wireless Communication Devices,” filed on Sep. 21, 2016, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Wireless communication systems are rapidly growing in both usage and the number of connected devices. A personal area network (“PAN”) may be defined as a computer network used for data transmission amongst devices such as computers, telephones, tablets, personal digital assistants, wearables, Internet of Things (IoT) devices, etc. For instance, a PAN may be used for communication between the devices themselves (e.g., interpersonal communication), or for connecting one or more devices to a higher level network and the Internet via an uplink, wherein one “master” device takes up the role as internet router. Furthermore, a wireless PAN is a network for interconnecting devices wherein the connections are wireless, using wireless technologies, such as Bluetooth. 
     A piconet consists of two or more devices occupying the same physical channel (e.g., synchronized to a common clock and hopping sequence). Typically, a piconet allows for one master (or primary) device to interconnect with up to seven active slave (or secondary) devices. For instance, examples of piconets include a cell phone connected to a computer, a laptop and a Bluetooth-enabled digital camera, or several tablet computers that are connected to each other. 
     When two or more independent, non-synchronized Bluetooth piconets overlap, a scatternet is formed in a seamless, ad-hoc fashion allowing for inter-piconet communication. In other words, a scatternet is a type of computer network consisting of two or more piconets, wherein a Bluetooth node may be a master in one piconet and a slave in one or more other piconets. However, piconet scheduling may not be coordinated so the shared master/slave node in the Bluetooth scatternet may have scheduling conflicts that result in packet drops. Accordingly, a need exists for mitigating scheduling conflicts in wireless communication devices within a scatternet. 
     SUMMARY 
     Some exemplary embodiments are directed to a method performed by at a wireless device configured as a slave in a first piconet and configured as a master in a second piconet. The method includes determining whether the wireless device has data to transmit over the second piconet to an other wireless device, determining an availability of a full slot in a first piconet schedule, selecting a data transmission scheme based on the availability of the full slot in the first piconet schedule and transmitting the data via the second piconet to the other wireless device in accordance with the selected data transmission scheme. 
     Some other exemplary embodiments are directed to a wireless device capable of communicating via a first piconet and a second piconet. The wireless device includes a baseband processor configured to determine whether the wireless device has data to transmit over the second piconet to an other wireless device, determine an availability of a full slot in a first piconet schedule and select a data transmission scheme based on the availability of the full slot in the first piconet schedule and a transceiver configured to transmit the data via the second piconet to the other wireless device in accordance with the selected data transmission scheme. 
     Still other exemplary embodiments are directed to a wireless device including a non-transitory memory having a program stored thereon and a processor. Execution of the program causes the processor to perform operations including determining whether the wireless device has data to transmit over the second piconet to an other wireless device, determining an availability of a full slot in a schedule of the first piconet, selecting a data transmission scheme based on the availability of the full slot in the schedule of the first piconet and transmitting the data via the second piconet to the other wireless device in accordance with the selected data transmission scheme. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exemplary embodiment of a scatternet including two piconets and for use in wireless audio headphones. 
         FIG. 2  shows an exemplary table for the packet types and payload of a bud-to-bud (“B2B”) piconet for wireless audio headphones. 
         FIG. 3  shows show an exemplary graph of a scheduling conflict between a B2B piconet and a source-to-bud (“S2B”) piconet for wireless audio headphones in communication with a source device. 
         FIG. 4  shows a transmission graph using the various sub-schemes for partial slot and full-slot-listen according to the exemplary embodiments described herein. 
         FIG. 5  shows the transmission graph for an example of a Partial-slot Scheme, as well as the impact on the IFS, according to the exemplary embodiments described herein. 
         FIG. 6  shows the transmission graph for a further example of a Partial-slot Scheme, as well as the impact on the IFS, according to the exemplary embodiments described herein. 
         FIG. 7  shows the transmission graph for an example of a Full-slot-listen Scheme, as well as the impact on the IFS, according to the exemplary embodiments described herein. 
         FIG. 8  shows an exemplary method for mitigating scheduling conflicts in wireless communication devices according to various embodiments described herein. 
         FIG. 9  shows an exemplary method for mitigating scheduling conflicts in wireless communication devices based on different schemes described herein. 
         FIG. 10  shows an exemplary device  1000  (e.g., wireless audio buds) for mitigating scheduling conflicts in wireless communication devices according to various embodiments described herein 
     
    
    
     DETAILED DESCRIPTION 
     The exemplary embodiments may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiments describe mitigating scheduling conflicts in wireless communication devices within a scatternet. It should be noted that while the exemplary embodiments described herein refer to scheduling conflicts in a Bluetooth scatternet, any type of network may implement the systems and methods described herein, and thus the various embodiments are not limited to a Bluetooth scatternet or piconets in general. Furthermore, while exemplary embodiments described herein may relate to a scatternet for use with wireless audio headphones (e.g., wireless earbuds), the systems and methods may be applied to connecting any wireless device and is not limited to wireless audio headphones. 
     Those skilled in the art will understand that the current methodology for establishing multiple piconets normally schedules the devices independently from one another. In other words, the scheduling between multiple piconets is not coordinated and may lead to scheduling conflicts between the connected devices. These scheduling conflicts may result in packet drops, retransmissions resulting in glitches, increased bandwidth usage, and general degradation of performance of both the network and the connected devices. In the exemplary embodiments that describe wireless audio buds, these packet drops, glitches, etc., may result in an unsatisfactory audio experience for the user. 
       FIG. 1  shows an exemplary embodiment of a scatternet  100  including two piconets  102  and  104  for use with two wireless audio headphones  108 ,  110  (e.g., wireless audio buds) in communication with a source device  106  (e.g., a mobile phone). The first piconet  102  is a source-to-bud (“S2B”) piconet, wherein the source device  106  is the master and a primary audio bud  108  is a slave. The second piconet  104  is a bud-to-bud (“B2B”) piconet, wherein the primary audio bud  108  is the master and a secondary audio bud  110  is a slave. In some implementations, one or more other devices also may be present in either or both of the first piconet  102  and the second piconet  104 . It is noted that while the source device  106  may not be aware of the presence of the secondary audio bud  110 , the secondary audio bud  110  may “eavesdrop” on the source device  106  as it communicates with the primary audio bud  108 . Specifically, the secondary audio bud  110  may know the schedule for communications between the secondary audio bud  110  and the primary audio bud  108  on the B2B piconet  104 . When there are no scheduled communications on the B2B piconet  104 , the secondary audio bud  110  may eavesdrop on the communication between the source device  106  and the primary audio bud  108 . Since it is generally assumed that the secondary audio bud  110  and the primary audio bud  108  will be in close physical proximity to each other, the secondary audio bud  110  may have generally the same (or in some cases, an even better) communication channel to listen to communications from the source device  106 . 
     The B2B piconet  104  may be used for audio synchronization and general control (e.g., battery life, adaptive frequency hopping (“AFH”) map updates, etc.) between the two audio buds  108  and  110 .  FIG. 2  shows an exemplary table  200  for the packet types and payload(s) of the B2B piconet  104 . 
     As illustrated in table  200 , the packet types may include NULL packets, POLL packets, ID packets, and payload packets (e.g., 2-DH1 Bluetooth packets). The NULL and POLL packets may be characterized as short general control packets that utilize the greatest portion of the B2B link. Thus, as can be seen from the table  200 , a great number of the packets exchanged over the B2B piconet  104  may have a small payload. As will be described in greater detail below, this characteristic of the B2B packets may be used to improve scheduling coordination between the B2B piconet  104  and the S2B piconet  102 . 
       FIG. 3  shows an exemplary graph  300  of a scheduling conflict between the B2B piconet  104  and the S2B piconet  102  for the wireless audio buds  108 ,  110  in communication with the source device  106 . Specifically, the graph  300  illustrates packet transmissions over time, wherein the highlighted portion  310  depicts the time in which conflicts may occur. That is, at the times within the highlighted portion  310 , both the B2B piconet  104  and the S2B piconet  102  may have communications scheduled that may lead to a conflict between the B2B piconet  104  and the S2B piconet  102 . As noted above, scheduling conflicts between the S2B piconet  102  and the B2B piconet  104  may cause Bluetooth audio packet drops and retransmissions, thereby resulting in audio glitches. When compared with a wired link between buds or headphones, the wireless B2B link may utilize a greater main link bandwidth and thereby can result in degraded overall performance. 
     According to the exemplary embodiments of the systems and methods described herein, multiple B2B link transmission schemes are proposed to avoid conflicting with S2B transmissions. These exemplary transmission schemes may include, but are not limited to, partial-slot schemes and full-slot-listen schemes, that utilize either S2B partial slots or S2B full slots, respectively, that do not occupy main link bandwidth (e.g., source link bandwidth). These exemplary schemes will be described in greater detail below, but may be described in general as using available time within the schedule of the S2B piconet  102  to schedule communications for the B2B piconet  104 . The time in the schedule of the S2B piconet  102  may be separated into multiple time slots and thus, the exemplary schemes are termed “slot” schemes because the schemes use one or more of these slots in the S2B piconet  102  schedule. Using available time in the S2B piconet  102  schedule (e.g., time when there are no communications scheduled for the S2B piconet  102 ) for B2B piconet  104  communications prevents scheduling conflicts between the two piconets  102  and  104 . 
       FIG. 4  shows a transmission graph  400  using the various sub-schemes for partial slot and full-slot-listen, according to the exemplary embodiments described herein. It may be considered in graph  400  that two (2) S2B slots  405  and  407  are illustrated. Two of the exemplary partial-slot schemes may be referred to as Partial-slot Scheme A and Partial-slot Scheme B. According to the exemplary partial-slot operations, the B2B piconet  104  may use remaining time in the S2B slot(s)  405 ,  407  when transmission and reception with the source device  106  via the S2B piconet  102  is finished. The two Partial-slot Schemes A and B may be differentiated based on whether the B2B poll and response are included within the same partial slot(s). One skilled in the art would understand that the poll refers to the master to slave transmission (e.g., primary audio bud  108  to secondary audio bud  110  transmission) while the response refers to the slave to master transmission (e.g., secondary audio bud  110  to primary audio bud  108  transmission). As indicated in  FIG. 4 , the Partial-slot Scheme A may use an S2B piconet partial slot  405 , incorporating the master poll  420  and slave response  430  in the same slot with inter-frame spacing (“IFS”). IFS may be defined as the time gap between frames for transmission/reception (“Tx/Rx”) switching, baseband processing, etc. For example, the IFS may be a hardware constraint to allow the various hardware components of the primary audio bud  108  and the secondary audio bud  110  to tune from the S2B piconet  102  to the B2B piconet  104 , switch between a transmission mode and a reception mode, etc. No communication should occur during this IFS to allow the hardware components to be set up properly to commence communications. Minimizing the IFS design (e.g., the time for IFS) may allow for communications to meet the maximum supported B2B payload requirements. 
     According to the transmission graph  400  of  FIG. 4 , the Partial-slot Scheme A allows for the available time in slot  405  after the S2B piconet communication  410  to include both the B2B communication  420  from primary audio bud  108  to the secondary audio bud  110 , as well as the B2B communication  430  from secondary audio bud  110  to the primary audio bud  108 . Accordingly, both of these the B2B communications  420  and  430  may be included in the same slot  405 , using the available time of the S2B slot  405  for the B2B link. 
     The Partial-slot Scheme B may also use an S2B piconet partial slot, however the master poll and slave response are not included in the same slot. For instance, the available time in slot  405  following the S2B piconet communication  440  may include the B2B communication  450  from primary audio bud  108  to the secondary audio bud  110 . However, the B2B communication  460  from secondary audio bud  110  to the primary audio bud  108  may take place in the next available slot. As will be described in greater detail below, the next available slot may or may not be the next slot  407 . That is, the B2B communication  460  may occur in slot  407 , but need not always occur in slot  407 . Instead, in some instances, the B2B communication  460  may occur during a later slot. Accordingly, while these B2B communications  450  and  460  may use the available time of the S2B slot for communications on the B2B link, these B2B communications  450  and  460  do not reside in the same slot. 
     In contrast to either of the Partial-slot Schemes, the exemplary Full-slot Scheme may use S2B full slots to listen and transmit communications. For instance, a B2B communication  480  may initiate listen up until a header portion of the S2B communication  470  to determine if the B2B communication  480  may use the remaining portion of the S2B slot  405 . The B2B communication  480  may also determine whether it may use the next S2B slot  407 , as well, if the source device  106  does not use it (e.g., for polling the audio buds  108  and  110 ). Accordingly, the B2B communication  480  may opportunistically utilize both the remaining portion of the S2B slot  405  and a further portion of the following S2B slot  407  for the communication from the primary audio bud  108  to the secondary audio bud  110 . The following S2B slot  407  may also include the B2B communication  490  from secondary audio bud  110  back to the primary audio bud  108 . 
     It should be noted that the above has described various exemplary slot schemes and the description below referring to  FIGS. 5-7  will describe these slot schemes in more detail. However, it has not yet been described when to select one or more of the exemplary schemes for use. The exemplary reasons or criteria to select any one of these schemes will be described in greater detail below. 
       FIG. 5  shows the transmission graph  500  for the Partial-slot Scheme A as well as an impact graph  560  on the IFS according to the exemplary embodiments described herein. In this example, it may be considered that the transmission graph  500  shows nine (9) slots  501 - 509  in the S2B piconet  102  schedule. For the purposes of this example, it may be considered that the slots  501 - 505  and  507 - 509  are being used for S2B piconet  102  communications and there is no available time in these slots for any B2B piconet  104  communications. However, the slot  506  may be considered to have available time that may be used for B2B piconet  104  communications. For example, the slot  506  may be the slot in the S2B piconet  102  schedule that is used for an acknowledgement (“ACK”) that is sent from the slave (primary audio bud  108 ) to the master (source  106 ). This ACK may take up little time of the slot  506  such that the remaining time of the slot  506  may be used for the B2B piconet  104  communications, specifically using the Partial-slot Scheme A. 
     This is shown in more detail in the exploded view  520  of the slot  506 . In this example, the slot  520  may be a 625 μs time slot. However, it is noted that the slot  506  having a length of 625 μs is only exemplary and other slot lengths may be used and may depend on the type of communication scheme being used for the piconet. The first portion of the slot  506  is used for the S2B communication  530  (e.g., the ACK transmitted from the primary audio bud  108  to the source  106 ). However, the remainder of the slot  506  is available for B2B piconet  104  communications. It is noted that since the primary audio bud  108  is a member of the S2B piconet  102  and the secondary audio bud  110  eavesdrops on the S2B piconet  102 , each of these devices may understand the schedule for the S2B piconet  102  and may understand that there is available time in the slot  506  for the B2B piconet  104  communications. 
     Thus, after the S2B communication  530 , the primary audio bud  108  and the secondary audio bud  110  may tune to the B2B piconet  104  (and take any other steps to prepare for communication via the B2B piconet  104 ) during the IFS  535 . After IFS  535 , the primary audio bud  108  may transmit a B2B communication  540  to the secondary audio bud  110 . At the completion of the B2B communication  540 , there is another IFS  545  where the primary audio bud  108  and the secondary audio bud  110  switch between the respective transmission and reception modes. After IFS  545 , the secondary audio bud  110  may transmit a B2B communication  550  to the primary audio bud  108 . At the completion of the B2B communication  550 , there is another IFS  555  where the primary audio bud  108  and the secondary audio bud  110  may tune to the S2B piconet  102  to prepare to receive the transmissions scheduled for the slot  507 . 
     As can be seen from this example, the Partial-slot Scheme A allows a complete round (poll/response) of B2B piconet communications (e.g., B2B communications  540  and  550 ) within the slot  506 . Referring back to the graph  500 , it can be seen that this scheme prevents any scheduling conflicts between the S2B piconet  102  and the B2B piconet  104  because the B2B piconet  104  communications (e.g., B2B communications  540  and  550 ) are limited to times when there are no scheduled S2B piconet  102  communications. This is generally made possible based on the fact that, as shown above in table  200 , the B2B communications have a size that allows the communications to be inserted into the available time within the S2B piconet  102  slots without degradation in the performance of the B2B piconet  104 . However, it is noted that there is no specific size requirement for the piconet communications to use the exemplary schemes described herein. Rather, the exemplary schemes may be used to avoid scheduling conflicts in the scatternet when the use of the schemes does not seriously degrade communications within any of the individual piconets. 
     The impact graph  560  illustrates the maximum supported B2B packet payload length for various transmission rates (e.g., basic date rate (“BDR”), enhanced data rate (“EDR”)-2, EDR-3, etc.) versus IFS for the Partial-slot Scheme A. As can be seen from the graph  560 , a shorter IFS may allow for higher B2B data transfers. 
       FIG. 6  shows the transmission graph  600  for a further example of a Partial-slot Scheme, as well as an impact graph  660  on the IFS, according to the exemplary embodiments described herein. Similar to the graph  500  of  FIG. 5 , the transmission graph  600  shows nine (9) slots  601 - 609  in the S2B piconet  102  schedule with the slots  601 - 605  and  607 - 609  being used for S2B piconet  102  communications. However, the slot  606  may be considered to have available time that may be used for B2B piconet  104  communications. Again, the slot  606  may be the slot in the S2B piconet  102  schedule that is used for the ACK that is sent from the slave (primary audio bud  108 ) to the master (source  106 ). This available time may be used for the B2B piconet  104  communications, specifically using the Partial-slot Scheme B. It should be noted that the slot  606  may also be used for other short S2B piconet  102  communications besides the ACK communication described above or the slot  606  may have no scheduled S2B piconet  102  communications, thereby leaving at least a portion of the slot  606  available for B2B piconet  104  communications. 
     This is shown in more detail in the exploded view  620  of the slot  606 . The first portion of the slot  606  is used for the S2B communication  630  (e.g., the ACK transmitted from the primary audio bud  108  to the source  106 ). However, the remainder of the slot  606  is available for B2B piconet  104  communications. Similar to the description above, the primary audio bud  108  and the secondary audio bud  110  may understand the schedule for the S2B piconet  102  and may understand that there is available time in the slot  606  for the B2B piconet  104  communications. 
     Thus, after the S2B communication  630  and the IFS  635 , the primary audio bud  108  may transmit a B2B communication  640  to the secondary audio bud  110 . At the completion of the B2B communication  640 , there is another IFS  645  where the primary audio bud  108  and the secondary audio bud  110  may tune to the S2B piconet  102  to prepare to receive the transmissions scheduled for the slot  607 . 
     As can be seen from this example, the Partial-slot Scheme B allows a single B2B piconet communication (e.g., B2B communication  640 ) within the slot  606 . In this example, the single B2B communication  640  may be considered a poll that is transmitted from the master (primary audio bud  108 ) to the slave (secondary audio bud  110 ). However, the single B2B communication may also be a response, e.g., a communication from the slave to the master. Thus, in this example, the primary audio bud  108  has transmitted a poll and will be expecting a response to that poll from the secondary audio bud  110 . This response is illustrated in  FIG. 6  as the B2B communication  650  that is not shown as occurring within the slot  606 . Specifically, in Partial-slot Scheme B, the B2B communication  650  will occur in a later slot when the later slot has available time for the B2B communication  650 . In this example, this later slot is some slot after slot  609  that is not illustrated in  FIG. 6 . However, it is possible that the next slot that has available time may be any slot that occurs after the slot  606 . In this manner, the complete communication (poll/response) between the primary audio bud  108  and the secondary audio bud  110  may be accomplished. It is noted that the reason for splitting the poll/response in the manner proposed by Partial-slot Scheme B is that the two B2B communications (including the required IFSs) may not fit in the remaining available time after the S2B communication  630  in the slot  606 . 
     Referring back to the graph  600 , it can be seen that this scheme also prevents any scheduling conflicts between the S2B piconet  102  and the B2B piconet  104  because the B2B piconet  104  communication (e.g., B2B communication  640 ) is limited to times when there are no scheduled S2B piconet  102  communications. 
     Similar to  FIG. 5 , the impact graph  660  illustrates the maximum supported B2B packet payload length for various transmission rates (e.g., BDR, EDR-2, EDR-3, etc.) versus IFS for the Partial-slot Scheme B. Once again, a shorter IFS may allow for higher B2B data transfers. 
       FIG. 7  shows the transmission graph  700  for an example of a Full-slot-listen Scheme, as well as an impact graph  760  on the IFS, according to the exemplary embodiments described herein. Prior to describing the transmission graph  700 ,  FIG. 7  also shows two exemplary Bluetooth Asynchronous Connection-Less (“ET ACL”) frame formats for the S2B communications, a BDR frame format  750  and an EDR frame format  755 . It can be seen that each of these frame formats  750  and  755  include an access code and header portion. One skilled in the art would understand that the access code identifies packets exchanged on a physical channel. Thus, packets sent in the same physical channel may be preceded by the same access code. Furthermore, the packet header contains information indicating a destination slave for an exemplary packet in a master-to-slave transmission slot. The header may also indicate the source slave for a slave-to-master transmission slot. 
     The components of the B2B piconet  104  (e.g., the primary audio bud  108  and the secondary audio bud  110 ) may listen to the communications of the S2B piconet  102 , including the access code and header portions, to determine whether the full slot will be available for B2B transmissions. That is, the contents of these two fields of the frame formats  750  and  755  will indicate to the primary audio bud  108  and the secondary audio bud  110  whether the S2B piconet  102  will be using the remainder of the slot. As shown in  FIG. 7 , the access code and header portions of the frame formats may have a length of 126 μs. Thus, if the remainder of the slot is available, the remaining time will be the length of the slot minus 126 μs. According to one embodiment, the availability may be determined based on information included in the access code and header. Alternatively, the availability may be determined based on the lack of an access code and/or header transmitted in the first portion of the slot. 
     For instance, if there is no energy detected by the slot start nominal time plus jitter requirement time (e.g., 10 μs), then the remaining slot time (e.g., 615 μs=625 μs−10 μs) and the next full slot (e.g., 625 μs) may be available. Alternatively, if there is energy detected, then the access code and header portion may be considered. Specifically, slot time may be available if the detected access code is not matched (e.g., the packet is not sent to the source piconet), or if the access code is matched but not the packet header (e.g., the packet is sent to the source piconet but not to the intended receiver). The remaining slot time may be based on the full slot (625 μs) less the current decision time taken from the slot start. Accordingly, this remaining slot time and the next full slot (625 μs) may be available. However, if the packet is addressed to the intended receiver, then the remaining slot time less the decision time and the next full slot may not be available for use. 
     The transmission graph  700  shows two slots  710  and  715 . In this example, each slot is 625 μs for a total length of 1250 μs for the two slots  710  and  715 . It is noted that in this example, two slots  710  and  715  are shown because the slots are arranged in an even/odd arrangement meaning that if there is no payload scheduled for transmission in the S2B piconet  102  in the even slot (e.g., slot  710 ) there will also be no transmission scheduled for the next odd slot (e.g., slot  715 ). For example, if no poll is sent, a corresponding response also will not be sent. Thus, once the primary audio bud  108  and the secondary audio bud  110  determine that the remainder of slot  710  is available, this will also mean that the entire slot  715  will also be available. Thus, in this example, the primary audio bud  108  and the secondary audio bud  110  will listen  720  for the first 126 μs of the slot  710 . If it is determined that there is no S2B communication scheduled for the remainder of the slot  710 , the primary audio bud  108  and the secondary audio bud  110  will understand that the remainder of slot  710  (e.g., 625 μs-126 μs) and the entire slot  715  (e.g., 625 μs) will be available for the B2B communications. This description will continue as if this is the case, e.g. the remainder of slot  710  and all of slot  715  are available for the B2B communications. 
     After the listen period  720 , there will be an IFS  725  when the primary audio bud  108  and the secondary audio bud  110  may tune to the B2B piconet  104  (and take any other steps to prepare for communication via the B2B piconet  104 ). After IFS  725 , the primary audio bud  108  may transmit a B2B communication  730  to the secondary audio bud  110 . The B2B communication  730  may be the poll, e.g., the transmission from the master (primary audio bud  108 ) to the slave (secondary audio bud  110 ). In this example, the B2B communication  730  is shown as using the remainder of the slot  710  and extending into slot  715 . This may be the case, but it also may be the case that the B2B communication  730  is completed prior to the end of the slot  710 . The point being that the complete poll may be transmitted even if it is longer than the remainder of the slot  710 . 
     At the completion of the B2B communication  730 , there is another IFS  735  where the primary audio bud  108  and the secondary audio bud  110  switch between the respective transmission and reception modes. After IFS  735 , the secondary audio bud  110  may transmit the response B2B communication  740  to the primary audio bud  108 . At the completion of the B2B communication  740 , there is another IFS  745  where the primary audio bud  108  and the secondary audio bud  110  may tune to the S2B piconet  102  to prepare for the transmissions scheduled for the next slot. 
     As can be seen from this example, the Full-slot-listen Scheme allows a complete round (poll/response) of B2B piconet communications (e.g., B2B communications  730  and  740 ) within the slots  710  and  715  that are not being used by the S2B communications. Thus, in a similar manner to the Partial-slot schemes, this scheme also prevents any scheduling conflicts between the S2B piconet  102  and the B2B piconet  104  because the B2B piconet  104  communications (e.g., B2B communications  730  and  740 ) are limited to times when there are no scheduled S2B piconet  102  communications. However, this Full-slot-listen Scheme also allows for a B2B communication to extend beyond the current slot. In contrast, in each of the Partial-slot schemes, the B2B communications that are started in a slot are completed prior to the end of that slot. 
     The impact graph  760  illustrates the maximum supported B2B packet payload length for various transmission rates (e.g., BDR, EDR-2, EDR-3, etc.) versus IFS for the Full-slot-listen Scheme. Unlike the impact graphs for the Partial-slot schemes, the impact graph  760  does not converge to zero (0) because, as described above, the B2B communications are allowed to extend beyond the current slot. 
       FIG. 8  shows an exemplary method  800  for mitigating scheduling conflicts in wireless communication devices according to various embodiments described herein. The method  800  will be described with reference to the scatternet  100  including the S2B piconet  102  having the source  106  (master) and the primary audio bud  108  (slave) and the B2B piconet  104  having the primary audio bud  108  (master) and the secondary audio bud  110  (slave). Each of the primary audio bud  108  and the secondary audio bud  110  may perform the operations of method  800 . 
     In  805 , the initial B2B transmission slot use is set to “Primary.” In other words, the primary audio bud  108  may be designated to use the B2B slot. In  810 , it may be determined whether there is any data to transfer or receive. This refers to data that is to be exchanged over the B2B piconet  104 . If there is no data to transmit or receive, the method  800  may loop until there is data to transmit or receive. If there is data to transmit or receive, the method  800  may advance to  815 . 
     In  815 , information regarding the data length and the link rate for transmission may be received. This information may be used later in the method as will be described in greater detail below. In  820 , it may be determined whether a full slot is available in the S2B communication. The manners of determining whether a full slot is available were described above with reference to  FIG. 7 . Thus, in this example, the Full-slot-listen Scheme takes priority, e.g., if it is possible to use the full slot scheme, this scheme will be used. If a full slot is available, the method  800  may advance to  825  to determine if fragmentation is required. Specifically, in  825  the transmission may be fragmented so that the data length can be supported according to the link rate. For example, referring to  FIG. 7 , even though the B2B communication may take up the remainder of slot  710  and the complete slot  715 , the amount of data that is to be transmitted, based upon the link rate of the B2B piconet  104 , may take more time than is provided in slots  710  and  715 . In this case, the data will be fragmented such that only the amount of data that can be transmitted in the time of slots  710  and  715  will be used. The remaining data will be transmitted at some later available time. After fragmentation in  825  (if used), the method  800  may advance to the transceiver block  855 . The operations associated with the transceiver block  855  will be described in greater detail below with respect to  FIG. 9 . 
     However, if a full slot is not available in  820 , the method  800  may advance to  830 . In  830 , the maximum payload may be calculated for each of the partial-slot schemes (e.g., Scheme A or Scheme B). Specifically, the maximum payload for B2B transmissions may be based on the available air-time (e.g., the remaining time in the current slot less any required IFS time) and the link rate information retrieved in  815 . For Scheme A, the maximum payload will consider both the poll and response since both communications will be sent in the available time in the current slot if Scheme A is ultimately used. For Scheme B, only the poll will be considered in the maximum payload determination because it will be considered that only the poll will be sent in the available time in the current slot. 
     Upon calculating the maximum payload length for both Partial-slot Scheme A and Partial-slot Scheme B, in  835  the data length retrieved in  815  may be compared to the maximum payload length for Partial-slot Scheme A. If the data length is less than or equal to the maximum payload length determined for Partial-slot Scheme A, the method  800  may advance to the transceiver block  855 . However, if the data length is greater than the maximum payload length determined for Partial-slot Scheme A, the method  800  may advance to  840 . 
     In  840 , the scheme may be designated as the Partial-slot Scheme B. That is, since the data length is greater than the maximum length allowed for Scheme A, Scheme B will be used. In  845 , the data length retrieved in  815  may be compared to the maximum payload length for Partial-slot Scheme B. If the data length is less than or equal to the maximum payload length determined for Partial-slot Scheme B, the method  800  may advance to the transceiver block  855 . However, if the data length is greater than the maximum payload length for Partial-slot Scheme B, the method  800  may advance to  850 . In  850 , the space time (“s.t.”) of the transmission data may be fragmented such that the data length is equal to the maximum payload length for Partial-slot Scheme B. The fragmenting may be similar to that described above with reference to  825 . For example, even though Partial-slot Scheme B is selected, the data length for the poll transmission may exceed the maximum payload length. Thus, the payload will be fragmented such that the payload may be transmitted in the current time slot. Upon fragmenting the transmission in  850 , the method  800  may advance to the transceiver block  855 . 
       FIG. 9  shows an exemplary method  900  for mitigating scheduling conflicts in wireless communication devices based on different schemes described herein. Specifically, method  900  may represent the operations of the transceiver block  855  of method  800  in  FIG. 8 . More specifically, the method  900  may represent the operations of the hardware transceiver devices in the primary audio bud  108  and the secondary audio bud  110 . 
     In  910 , the transceivers of the devices of the B2B piconet  104  (e.g., the primary audio bud  108  and the secondary audio bud  110 ) may switch to a B2B piconet frequency. This operation may correspond to the IFS  535 ,  635  and  725  of  FIGS. 5-7 , respectively. In  915 , it may be determined whether the scheme has been designated as the Partial-slot Scheme B. If the B2B communications is not using Scheme B, the method  900  may advance to  945  for Partial-slot Scheme A and Full-slot-listen Scheme operations. In  945 , it is presumed that the scheme is either Partial-slot Scheme A or Full-slot-listen Scheme (e.g., not B). In  945 , the primary audio bud  108  may transmit data while the secondary audio bud  110  may receive data. For example, if Partial-slot Scheme A is currently being used, the primary audio bud  108  will transmit the B2B communication  540  of  FIG. 5  and the secondary audio bud  110  will receive the B2B communication  540  during  945 . If the Full-slot-listen Scheme is currently being used, the primary audio bud  108  will transmit the B2B communication  730  of  FIG. 7  and the secondary audio bud  110  will receive the B2B communication  730  during  945 . 
     In  950 , the transceivers of the primary audio bud  108  and the secondary audio bud  110  may switch their corresponding operating mode (e.g., the primary audio bud  108  transceiver from transmission mode to reception mode and the secondary audio bud  110  transceiver from reception mode to transmission mode). This operation may correspond to the IFS  545  and  735  of  FIGS. 5 and 7 , respectively. Following the switch, in  955  the primary audio bud  108  may receive data while the secondary audio bud  110  may transmit data. For example, if Partial-slot Scheme A is currently being used, the secondary audio bud  110  will transmit the B2B communication  550  of  FIG. 5  and the primary audio bud  108  will receive the B2B communication  550  during  955 . If the Full-slot-listen Scheme is currently being used, the secondary audio bud  110  will transmit the B2B communication  740  of  FIG. 7  and the primary audio bud  108  will receive the B2B communication  740  during  945 . When this is complete, the method  900  will advance to  960  that will be described in greater detail below. 
     Returning to  915 , if the B2B communication is using Scheme B, the method  900  may advance to  920 . In  920 , it may be determined whether the B2B slot use is by the primary audio bud  108 . As described with reference to  805  of method  800 , the B2B slot use is initialized to the primary audio bud  108 . If the B2B slot is currently set to the primary audio bud  108 , in  925  the primary audio bud  108  may transmit data while the secondary audio bud  110  may receive data. For example, the primary audio bud  108  will transmit the B2B communication  640  of  FIG. 6  and the secondary audio bud  110  will receive the B2B communication  640  during  925 . Following  925 , the B2B slot use may be set to the secondary audio bud  110  in  930  and the method  900  may advance to  960  that will be described in greater detail below. 
     If it is determined in  920  that the B2B slot use is not by the primary audio bud  108 , in  935  the primary audio bud  108  may receive data while the secondary audio bud  110  may transmit data. For example, the secondary audio bud  110  will transmit the B2B communication  650  of  FIG. 6  and the primary audio bud  108  will receive the B2B communication  650  during  935 . Following  935 , the B2B slot use may be set to the primary audio bud  108  in  940  and the scheme may be designated as “not B.” Furthermore, the method  900  may advance to  960 . 
     Thus, after one of operations  930 ,  940  or  955 , the method  900  advances to  960  where the transceivers of the devices of the B2B piconet  104  (e.g., the primary audio bud  108  and the secondary audio bud  110 ) may switch to a S2B piconet frequency. This operation may correspond to the IFS  555 ,  645  and  745  of  FIGS. 5-7 , respectively. 
     It should be noted that after step  960  is completed, referring back to  FIG. 8 , the method  800  will return to  810  to determine if there is any data to be transmitted or received. More specifically, upon completing the method  900  as described in the transceiver block  855  of  FIG. 9 , the operations of the method  800  may restart at step  810  with a possible change in conditions (e.g., B2B slot use flag, scheme flag, etc.). For instance, as noted above, the B2B slot use may be set to “Primary” at  805  upon an initial operation of method  800 . However, this condition may change from “Primary” to “Secondary” when the method  800  reaches  855  and, subsequently reaches  930  in method  900 . Such a change in this condition will change the operation of the transceiver  855  (specifically, at  920 ) upon the next iteration of method  800 . Additionally, the scheme may be set to “Scheme B” at  840  upon comparing the data length to a maximum payload data length. However, this condition may change from “Scheme B” to “Scheme not-B” when the method  800  reaches  855  and, subsequently reaches  940  in method  900 . Such a change in this condition will change the operation of the transceiver  855  (specifically, at  915 ) upon the next iteration of method  800 . 
       FIG. 10  shows an exemplary device  1000  (e.g., wireless audio buds) for mitigating scheduling conflicts in wireless communication devices according to various embodiments described herein. The device  1000  may represent any electronic device (e.g., primary audio bud  108 ) that is configured to perform wireless functionalities, such as but not limited to communicating with a master device (e.g., the source device  106 ) as well as a slave device (e.g., the secondary audio bud  110 ). However, it is noted that the device  1000  may also represent the other components of the exemplary scatternet, such as the source device  106  and the secondary audio bud  110 . 
     Furthermore, it is noted that the device  1000  is not limited to audio buds and may represent any portable wireless device, such as, but not limited to a wearable computing device, a mobile phone, a tablet computer, a personal computer, a VoIP telephone, an Internet of Things (IoT) device, etc. The device  1000  may also be a client stationary device such as a desktop terminal. 
     The exemplary device  1000  may include a transceiver  1010  connected to an antenna  1015 , a baseband processor  1020  and a controller  1030 , as well as other components. The other components may include, for example, a memory, a battery, ports to electrically connect the device  1000  to other electronic devices, etc. The controller  1030  may control the communication functions of the transceiver  1010  and the baseband processor  1020 . In addition, the controller  1030  may also control non-communication function related to the other components, such as the memory, the battery, etc. 
     According to one embodiment, the baseband processor  1020  may be a chip compatible with a wireless communication standard, such as Bluetooth. The baseband processor  1020  may be configured to execute a plurality of applications of the device  1000 . For example, the applications may include the above-referenced methods related to the exemplary embodiments, such as but not limited to, the selection and implementation of the Partial-slot Schemes A and B and/or the Full-slot-listen Scheme as described in method  800   FIG. 8 . Additionally, the transceiver  1010  may also be configured to execute a plurality of applications of the device  1000 . For example, the applications may include the above-referenced methods related to the exemplary embodiments, such as but not limited to, the selection and implementation of the Partial-slot Schemes A and B and/or the Full-slot-listen Scheme as described in method  900   FIG. 9 . It should also be noted that the baseband processor  1020 , the controller  103  and the transceiver  1010  may include circuitry (with or without firmware) to perform the functionalities described herein. That is, the functionalities described herein are not required to be implemented as applications, but may also be implemented as chip level or board level integrated circuits. 
     Finally, in the above examples, various transmission schemes including slots, lengths of the slots and transmission formats have been described. It should be understood that these are all exemplary and those skilled in the art will understand that using the principles described herein for the full and partial slot schemes may be applied to different transmission schemes to accomplish scheduling coordination for different piconets. 
     It will be apparent to those skilled in the art that various modifications may be made in the present disclosure, without departing from the spirit or scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

Metadata:
Filing Date: 20170919
Publication Date: 20191224
Grant Date: 20191224
Priority Date: 20160921
Inventors: LI, LEI
CHEN, XIAOJUN
REDDY, VUSTHLA SUNIL
NARANG, MOHIT
WU, QIYANG
AGBOH, PETER M.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W72/52", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/52", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W84/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W84/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W4/80", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/1263", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W4/80", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W84/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W4/80", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/1263", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/1252", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/70", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 61617646