The present invention relates generally to communication systems, and specifically to synchronization in a communication system.
IEEE 802.11 based wireless and mobile networks also called Wireless Fidelity (Wi-Fi) have experience rapid growth. Wi-Fi is a mechanism that allows an electronic device to exchange data wirelessly over a computer network. A device enabled with Wi-Fi, such as a personal computer, video game console, smart-phone, tablet, or digital audio player, can connect to a network resource such as the Internet via a wireless network access point. An access point (or hotspot) can have a range of about 22 meters (65 ft) indoors and a greater range outdoors. Hotspot coverage can comprise an area as small as a single room with walls that block radio signals or a large area, as much as many square miles, covered by multiple overlapping access points. A wireless access point (AP) connects a group of wireless devices to an adjacent wired LAN. An access point resembles a network hub, relaying data between connected wireless devices in addition to a (usually) single connected wired device, most often an Ethernet hub or switch, allowing wireless devices to communicate with other wired devices.
The various IEEE 802.11 standards provide for 14 possible channels distributed over a range from 2.402 GHz to 2.483 GHz with each channel being 24 MHz wide. The various IEEE 802.11 standards call for periodic channel scan cycles over at least a majority of the 14 channels to allow for communication handoffs between access points. Scanning can be divided into active and passive scanning. During an active scan, a station (STA) broadcasts a packet requesting that all access points (APs) in those specific channels impart their presence and capability with a probe response. In a passive scan, the STA listens passively for the AP beacons containing all necessary information, such as beacon interval, capability information, supported rate and other parameters associated with the AP.
A multi-role communication device allows a user to operate the device in a multi-role mode, where the device can operate in a plurality of communication roles for separate communication with multiple devices on the same channel (e.g., to act as both a station and an access point). The emerging desire for increased connectivity usage employing single multi-role devices requires support of wireless local area network (WLAN) concurrent multi-role operation on two bands/channels by a single Baseband processor. Therefore, the multi-role device can switch between providing resource allocation in a station mode and an access point mode, and/or can provide communication capability with other devices based on a direct communicative coupling. The communication between the access point and other communication devices can be accomplished based on different communication roles that can be time-division multiplexed.
In accordance with an aspect of the invention, a communication system is provided. The communication system includes a plurality of multi-role wireless communication devices communicatively coupled to transmit and receive data between at least one network access point and between each other in a plurality of communication roles in a time-division multiplexed manner. At least one of the at least one network access point and at least one of the plurality of multi-role wireless communication devices can be configured to transmit a timing beacon configured to synchronize a time-division multiplexing of at least one corresponding communication role associated with each of the plurality of multi-role wireless communication devices.
In accordance with another aspect of the invention, a multi-role wireless communication device is provided. The device includes a controller comprising a processor, memory, and a multi-role scheduler configured to implement a scheduling algorithm associated with time-division multiplexing of a plurality of communication roles for communication with at least one network access point and at least one other multi-role wireless communication device. The controller can be further configured to generate a timing beacon that is configured to synchronize a time-division multiplexing of at least one corresponding communication role associated with the at least one other multi-role wireless communication device with the scheduling algorithm. The device also includes at least one transceiver collectively configured to transmit and receive data in each of the plurality of communication roles based on the time-division multiplexing according to the scheduling algorithm and to periodically transmit the timing beacon at predetermined timing intervals.
In accordance with an aspect of the present invention, a method for synchronizing communications in a communication system comprising a plurality of multi-role wireless communication devices is provided. The method includes implementing a scheduling algorithm associated with time-division multiplexing of a plurality of communication roles in each of the plurality of multi-role wireless communication devices for communication of the plurality of multi-role wireless communication devices with each other and with at least one network access point. The method also includes transmitting a timing beacon comprising timing data associated with at least one of the plurality of communication roles to each of the plurality of multi-role wireless communication devices. The method also includes time-aligning the at least one corresponding communication role of each of the plurality of multi-role wireless communication devices based on the timing data. The method further includes transmitting and receiving data between the plurality of multi-role wireless communication devices at time slots associated with the at least one of the plurality of communication roles.
The multi-role wireless communication devices 14 and 16 can be configured to communicate via a plurality of different communication roles. As described herein, a “communication role” or “role” can be defined as communicating as a specific function of a wireless local area network (WLAN). Different communication roles can communicate with different communication protocols or over one of a plurality of channels within a given communication protocol. For example, a communication role can correspond to providing the function of communicating in a Wi-Fi WLAN station (STA) communication role, an access point communication role, a WLAN peer-to-peer communication role, or a Bluetooth (BT) File Transfer Protocol (FTP) communication role.
As an example, the wireless network system 10 can, at least in part, conform to one of the versions of the IEEE 802.11 standards for Wi-Fi networks. The Wi-Fi AP 12 can be configured to transmit radio frequency (RF) communications through an antenna 18 over respective wireless communication links 20 to one or both of the multi-role wireless communication devices 14 and 16 via an antenna 22 associated with each of the multi-role wireless communication devices 14 and 16. The Wi-Fi AP 12 and one or more other Wi-Fi APs (not shown) can be connected to the same or different wired networks (not shown). Additionally, while the example of
In the example of
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In the example of
At a time T0, the first multi-role wireless communication device 14 switches to the Wi-Fi WLAN STA role 56. Thus, the first multi-role wireless communication device 14 is configured to communicate with the Wi-Fi AP 12 beginning at the time T0. At a time T1, the second multi-role wireless communication device 16 switches to the BT FTP role 58, such as associated with one or more of the communication links 30. Thus, the second multi-role wireless communication device 16 is configured to communicate with one or more of the communication devices 28 beginning at the time T1. At a time T2, the first multi-role wireless communication device 14 switches from the Wi-Fi WLAN STA role 56 to the BT FTP role 58. Therefore, at the time T2, both of the first and second multi-role wireless communication devices 14 and 16 can communicate with the communication devices 28 via the respective communication links 30. Accordingly, in the example of
At a time T3, the second multi-role wireless communication device 16 switches from the BT FTP role 58 to the Wi-Fi WLAN P2P role 60. Therefore, at the time T3, the second multi-role wireless communication device 16 can be configured to communicate with the first multi-role wireless communication device 14. However, at the time T3, the first multi-role wireless communication device 14 is still communicating via the BT FTP role 58. Therefore, any data packets that are being transmitted by the second multi-role wireless communication device 16 to the first multi-role wireless communication device 14 are not received by the first multi-role wireless communication device 14 because the at least one transceiver 24 of the first multi-role wireless communication device 14 is not configured to receive data of the Wi-Fi WLAN P2P role 60 at that time. As a result, the second multi-role wireless communication device 16 may not receive the appropriate acknowledgements to indicate successful receipt of the data packets at the first multi-role wireless communication device 14. Accordingly, the data packets not received by the first multi-role wireless communication device 14 may be continuously retransmitted by the second multi-role wireless communication device 16 until such acknowledgement is received.
At a time T4, the first multi-role wireless communication device 14 switches from the BT FTP role 58 to the Wi-Fi WLAN P2P role 60. Therefore, at the time T4, the first multi-role wireless communication device 14 can be configured to transmit and receive data to and from the second multi-role wireless communication device 16. The data packets that have been transmitted by the second multi-role wireless communication device 16 can now be acknowledged by the first multi-role wireless communication device 14, and the first multi-role wireless communication device 14 can then likewise transmit data packets to the second multi-role wireless communication device 16.
At a time T5, the second multi-role wireless communication device 16 switches from the Wi-Fi WLAN P2P role 60 back to the Wi-Fi WLAN STA role 56 for communication with the Wi-Fi AP 12. However, at the time T5, the first multi-role wireless communication device 14 remains set for communication in the Wi-Fi WLAN P2P role 60, but can no longer communicate with the second multi-role wireless communication device 16 based on the second multi-role wireless communication device 16 having switched to the Wi-Fi WLAN STA role 56. As a result, similar to as described previously, data packets transmitted by the first multi-role wireless communication device 14 are not received by the second multi-role wireless communication device 16, which is indicated by a lack of acknowledgements received by the first multi-role wireless communication device 14. Therefore, such data packets can be continuously retransmitted until a time T6, at which the first multi-role wireless communication device 14 likewise switches back to the Wi-Fi WLAN STA role 56 and the time-divisions 52 and 54 repeat (i.e., as at the time T0). Therefore, such data packets could be lost as a result of the first multi-role wireless communication device 14 switching to the Wi-Fi WLAN STA role 56, and/or based on expiration of an acknowledgement timer, resulting in a loss of connection between the first and second multi-role wireless communication devices 14 and 16.
Therefore, based on the respective independent scheduling of the communication roles 56, 58, and 60 by the multi-role schedulers 34 of the first and second multi-role wireless communication devices 14 and 16, the time-divisions 52 and 54 are substantially misaligned. Based on the misalignment of the time-divisions 52 and 54, the first and second multi-role wireless communication devices 14 and 16 have a window of mutual communication of a limited duration between the time T5 and the time T4, which is a window of time that is more narrow than a full time slot dedicated to communication in the Wi-Fi WLAN P2P role 60. Accordingly, the communication bandwidth between the first and second multi-role wireless communication devices 14 and 16 can be substantially limited based on the misalignment between the first and second time-divisions 52 and 54. In addition, if the misalignment between the time-divisions is large enough, there is a possibility of a communication link between the first and second multi-role wireless communication devices 14 and 16 being severed, such as based on expiration of an acknowledgement timer (e.g., too much time elapsed after transmission of a data packet without an acknowledgement). Furthermore, while the example of
Referring back to the example of
As an example, the first multi-role wireless communication device 14 can be configured as a group owner (GO) in a given communication session between the first and second multi-role wireless communication devices 14 and 16, such that the second multi-role wireless communication device 16 is configured as a client device. Therefore, the first and second multi-role wireless communication device 14, configured as the GO device, can act as a master with respect to the second multi-role wireless communication device 16, configured as the client device. Accordingly, the first multi-role wireless communication device 14 can transmit the timing beacon, such that the multi-role scheduler 34 of the second multi-role wireless communication device 16 can synchronize its scheduling algorithm to that of the scheduling algorithm of the multi-role scheduler 34 of the first multi-role wireless communication device 14.
As yet another example, the Wi-Fi AP 12 can be configured to transmit the timing beacon, such as via the communication links 20. As an example, the Wi-Fi AP 12 can transmit the timing beacon to all multi-role wireless communication devices to which it is communicatively coupled, such that the Wi-Fi AP 12 can dictate a time-division multiplexing scheme for all of the multi-role wireless communication devices (e.g., the multi-role wireless communication devices 14 and 16) with which it is coupled for synchronization of the time-division multiplexing schemes. As yet a further example, more than of the Wi-Fi AP 12 and/or the multi-role wireless communication devices 14 and 16 can periodically transmit timing beacons, such that each of the multi-role wireless communication devices 14 and 16 can incrementally adjust their respective time-divisions 52 and 54 forward or backward in time after each receipt of a timing beacon. As a result, the time-divisions 52 and 54 can eventually be substantially synchronized. Therefore, the timing beacon can be transmitted from any of a variety of devices in the communication system 10.
The timing beacon can be substantially periodically transmitted, such as to account for substantial differences in time-divisions and/or to accommodate new communication devices that are added to the communication system 10. For example, the periodic transmission of the timing beacon can occur at periodic predetermined time intervals (e.g., 100 millisecond intervals). As another example, the timing beacon can be transmitted after a predetermined number of transitions between different communication roles. At each transmission, the timing beacon can be transmitted according to one or more of the communication roles associated with the multi-role wireless communications devices 14 and 16. Therefore, it can be substantially assured that the timing beacon is received and processed by the respective multi-role wireless communications devices 14 and 16 regardless of the communication role with which they are communicating at the time of receipt of the timing beacon.
At a time T7, the multi-role wireless communication device 14 switches to the BT FTP role 58, such as associated with one or more of the communication links 30. Thus, the multi-role wireless communication device 14 is configured to communicate with one or more of the communication devices 28 beginning at the time T7. At a time T8, the multi-role wireless communication device 14 switches from the BT FTP role 58 to the Wi-Fi WLAN P2P role 60. Therefore, at the time T8, the multi-role wireless communication device 14 can be configured to communicate with the other multi-role wireless communication devices, such as the multi-role wireless communication device 16. At a time T9, the multi-role wireless communication device 14 switches from the Wi-Fi WLAN P2P role 60 to the Wi-Fi WLAN STA role 56. Thus, at the time T9, the multi-role wireless communication device 14 can communicate with the Wi-Fi AP 12, such as via the communication link 20.
At a time T10, the multi-role wireless communication device 14 can be configured to transmit a timing beacon 104. For example, the transmission of the timing beacon 104 can be based on expiration of a predetermined periodic time interval, or can be based on a predetermined number of communication role transitions. In the example of
At a time T11, the multi-role wireless communication device 14 can switch back to the BT FTP role 58. Therefore, the multi-role wireless communication device 14 can again communicate with one or more of the communication devices 28 beginning at the time T11, and thus the time division 102 can repeat switching between the sequence of communication roles 56, 58, and 60. At a future time, such as after expiration of a predetermined time interval or a predetermined number of transitions of the time-division 102, the multi-role wireless communication device 14 can again transmit the timing beacon 104, such as described previously.
At a time T12, the multi-role wireless communication device 14 switches to the BT FTP role 58, such as associated with one or more of the communication links 30. Thus, the multi-role wireless communication device 14 is configured to communicate with one or more of the communication devices 28 beginning at the time T12. At a time T13, the multi-role wireless communication device 14 switches from the BT FTP role 58 to the Wi-Fi WLAN P2P role 60. Therefore, at the time T13, the multi-role wireless communication device 14 can be configured to communicate with the other multi-role wireless communication devices, such as the multi-role wireless communication device 16. In addition, in the example of
At a time T14, the multi-role wireless communication device 14 switches from the Wi-Fi WLAN P2P role 60 to the Wi-Fi WLAN STA role 56. Thus, at the time T14, the multi-role wireless communication device 14 can communicate with the Wi-Fi AP 12, such as via the communication link 20. At a time T15, the multi-role wireless communication device 14 switches back to the BT FTP role 58, and at a time T16, the multi-role wireless communication device 14 switches back to the Wi-Fi WLAN P2P role 60. In the example of
Therefore, the multi-role wireless communication devices 14 and 16 can achieve substantially more efficient communication with each other, such as via the communication link 26, based on alignment of the respective communication role (e.g., the Wi-Fi WLAN P2P role 60) with which they communication with each other. It is to be understood that, while the example of
It is to be understood that the communication system 10 is not limited to the examples demonstrated in the examples of
Both the display 252 and the I/O devices 254 are coupled to a controller 256. The controller 256 includes a microcontroller/microprocessor 258 (labeled as μP), a memory 260, and a multi-role scheduler 271. The user can input data into the multi-role wireless communication device 250 via the display 252 and/or the I/O devices 254. The data can be processed by the microcontroller/microprocessor 258 and/or stored in the memory 260. In addition, data can be retrieved from the memory 260 and displayed on the display 252. The multi-role scheduler 271 can be configured to implement a scheduling algorithm that is configured to arrange time slots associated with the time-division multiplexed manner of the plurality of communication roles with which the multi-role wireless communication device 250 can communicate.
The multi-role wireless communication device 250 further includes an internal power supply 268. The internal power supply 268 could be, for example, a rechargeable battery, such as a lithium ion battery. The internal power supply 268 is coupled to a power input 270, such that an external power supply (e.g., a DC power adaptor) could be plugged into the power input 270. The external power supply could thus supply power to the multi-role wireless communication device 250 while it is plugged into the power input 270, allowing the multi-role wireless communication device 250 to operate from the external power supply while the internal power supply 268 recharges.
The multi-role wireless communication device 250 includes a multi-role baseband controller 262 that operates to manage the separate roles of the multi-role wireless communication device 250 with respect to the communication roles with which the multi-role wireless communication device 250 can communicate. For example, the multi-role baseband controller 262 can operate in a Wi-Fi WLAN STA role, a BT FTP role, and a Wi-Fi WLAN STA role, as well as other communication roles. The multi-role baseband controller 262 is coupled to a multi-role transceiver 264 that is configured to up convert data from the multi-role baseband controller 262 to be transmitted to other wireless devices over an antenna 266, and down convert data received at the antenna 266 from other wireless devices and to be provided to the multi-role baseband controller 262. The multi-role baseband controller 262 is coupled to the controller 254, such that transmitted and received data can be processed by the microcontroller/microprocessor 258 and/or stored in the memory 260.
The multi-role baseband controller 262 manages the functionality associated with transmitting, receiving and time multiplexing data between the communication roles of the multi-role wireless communication device 250, such as based on the scheduling algorithm set by the multi-role scheduler 271. Therefore, the multi-role baseband controller 262 can allow the multi-role wireless communication device 250 to communicate with other wireless communication devices, such as Wi-Fi APs, other multi-role wireless communication devices, and other communication devices, based on a plurality of different communication roles.
The multi-role wireless communication device 250 can also include an additional communication controller 72 coupled to an additional communication transceiver 74. The additional communication transceiver 74 is coupled to an antenna 76 for transmitting and receiving communications over other communication networks such as a cellular network (e.g., 3G network, 4G network, etc.). Additional communication controllers and transceivers can be provided for other communication network, such as, for example, IEEE 802.15 (i.e., Bluetooth).
As an example, the multi-role baseband controller 262 can be configured to generate a timing beacon signal, such as generated by the microcontroller/microprocessor 258. The timing beacon can be configured to synchronize the time-division multiplexing of communication roles of other multi-role wireless communication devices with the time-division of the multi-role wireless communication device 250, as set by the multi-role scheduler 271. For example, the timing beacon can include timing data, such as time stamps, associated with the transitions associated with one or more of the communication roles, such as dictated by the multi-role scheduler 271. Therefore, the multi-role wireless communication device 250 can periodically transmit the timing beacon, such as based on predetermined timing intervals or communication role transitions, when operating as a GO device to enable other multi-role wireless communication devices to synchronize their respective communication role time-divisions with the time-division of the multi-role wireless communication device 250. As another example, the multi-role baseband controller 262 can be configured to receive a timing beacon from another wireless communication device, such as another multi-role wireless communication device. As a result, the multi-role scheduler 271 can synchronize the time slots of one or more of the communication roles to the time-division of the transmitting communication device based on the timing beacon. Accordingly, the time-division of one or more of the communication roles of the multi-role wireless communication device 250 can be substantially synchronized with the transmitting communication device.
In view of the foregoing structural and functional features described above, certain methods will be better appreciated with reference to
At 306, a time-alignment of the at least one of the plurality of communication roles of the multi-role wireless communication device is adjusted based on the timing data. The timing alignment can occur based on synchronization of the other communication devices to the device that transmitted the timing signal. At 308, data between the multi-role wireless communication device and the at least one other multi-role communication device is transmitted and received at time slots associated with the time-aligned at least one of the plurality of communication roles. The time slots can be associated with a Wi-Fi WLAN P2P communication role.
What have been described above are examples of the invention. It is, of course, not possible to describe every conceivable combination of components or method for purposes of describing the invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the invention are possible. Accordingly, the invention is intended to embrace all such alterations, modifications, and variations that fall within the scope of this application, including the appended claims.