Patent Application
20060046736
For portable electronic devices such as PDAs (personal digital assistants), cellular telephones and laptop computers, battery life is often a critical factor in useability and user satisfaction. Frequently, it is necessary to make difficult trade-offs to preserve an adequate battery life in a portable electronic device. For example, it is typically a desired feature of such devices to provide wireless data communication to and from such devices at as high a bandwidth as possible. However, higher bandwidth communication interfaces typically draw more power than lower bandwidth communication interfaces. Accordingly bandwidth, and thus convenience of communication, is often traded off against battery life in portable electronic devices.
As seen from
In addition, the system 100 includes a central controller 106 that is in communication with the access points 104 and may manage data communications sent to or from the mobile communication device 102 via one or more of the access points 104. The central controller 106 may, for example, be in communication with other devices, such as server computers, personal computers, other mobile communication devices (all not shown) via other communication links such as a data communication network (not shown; e.g., the Internet).
The mobile communication device 102 also includes one or more input/output (I/O) devices coupled to the control circuit 200. The I/O devices are represented by block 202 in
Further, in accordance with some embodiments, the mobile communication device 102 may include a plurality of wireless data communication transceivers, such as a Bluetooth transceiver 206 and a Wi-Fi transceiver 208, which are coupled to and controlled by the control circuit 200. Each of the transceivers 206, 208 may include a suitable antenna (not separately shown) which may be shared with the other transceiver.
The mobile communication device 102 may include other components, which are not shown, such as a housing which is shaped and sized to fit in a user's palm and which contains and/or supports all the other components of the mobile communication device 102. In some embodiments, the mobile communication device 102 may be a PDA, a cellular telephone, or a laptop computer, for example.
As is familiar to those who are skilled in the art, the Bluetooth transceiver 206 is a relatively low-cost, low-power, low-bandwidth device as compared to the Wi-Fi transceiver 208. The Wi-Fi transceiver 208, on the other hand, may provide roughly an order of magnitude higher bandwidth than the Bluetooth transceiver 206, while drawing perhaps an order of magnitude more power than the Bluetooth transceiver 206.
In accordance with some embodiments, the Wi-Fi transceiver 208 may normally be turned off, but may be turned on automatically by the control circuit 200 when there is a need for high bandwidth data communication by the mobile communication device 102. Because the Wi-Fi transceiver 208 may be more power-efficient than the Bluetooth transceiver 206 when a relative large quantity of data is to be transmitted or received, this arrangement may provide the mobile communication device 102 with “the best of both worlds”—relatively low power consumption by usually powering down the Wi-Fi transceiver and using the low power Bluetooth transceiver in standby mode to keep the mobile communication device in touch with the system 100, while using the Wi-Fi transceiver when high-bandwidth communication is needed.
The access point 104 may also include plural wireless data communication transceivers compatible with the data communication protocols utilized by the mobile communication devices to be supported by the system 100. For example, the access point 104 may include a Bluetooth transceiver 302 and a Wi-Fi transceiver 304, both coupled to and controlled by the control circuit 300.
In addition, the access point 104 may include one or more memory devices 306 coupled to the control circuit 300 to serve as program and/or working memory or the like, and may include one or more communication devices 308 to, e.g., allow the access point 104 to exchange data communication with the central controller 106. Unlike the mobile communication device 102, the access point may lack a user interface.
Since the Bluetooth transceiver of the mobile communication devices may have a relatively short range, the system 100 may include additional access points having only Bluetooth transceivers as well as main access points that have both Bluetooth and Wi-Fi transceivers.
As indicated at 400, the access point 104 broadcasts at regular intervals the inquiry (“INQ”) signal called for by the Bluetooth communication protocol to allow the access point 104 to be made aware of any nearby mobile communication devices that support Bluetooth communications. The INQ signals 400 may contain Bluetooth addressing information for the access point in question. In other embodiments, the INQ signals merely indicate the presence of the access point and do not contain addressing information.
One of the INQ signals 400 may be received by the Bluetooth transceiver 206 of a nearby mobile communication device 102. The mobile communication device 102 responds to the INQ signal 400 with a Bluetooth signal 402. The signal 402 may include the Bluetooth address information (BT-MAC address—where “MAC” stands for Media Access Control) for the mobile communication device 102.
The Bluetooth transceiver 302 of the access point receives the signal 402. In response, the Bluetooth transceiver 302 of the access point sends a Bluetooth signal 404, addressed to the Bluetooth address of the mobile communication device. The signal 404 includes Wi-Fi address information (e.g., WF-ESSID—Wi-Fi extended service set identification—or other address information) by which the access point may be addressed in accordance with the Wi-Fi wireless data communication protocol.
The Bluetooth transceiver 206 of the mobile communication device receives the signal 404. The mobile communication device is now able to establish a wireless data communication connection (“CON”, as indicated at 406) with the access point in accordance with either one of the Bluetooth and Wi-Fi protocols, depending on the current needs of the mobile communication device.
In some embodiments, if the access point includes only a Bluetooth transceiver and not a Wi-Fi transceiver, the WF-MAC provided to the mobile communication device at 404 may be that of another nearby access point that includes a Wi-Fi transceiver, and the mobile communication device may connect to that other access point if Wi-Fi communication is currently the appropriate protocol for the mobile communication device to use.
In some embodiments, the handshaking procedure of
At 500 in
Then, as indicated at 504 in
The process of
If a positive determination is made at 602 (i.e., if it is determined that high-bandwidth data communication is in order) then the mobile communication device, via its control circuit 200, may automatically select the Wi-Fi transceiver 208 for operation, as indicated at 604. In some embodiments (e.g., when the mobile communication device is operating with a very limited supply of power), the Wi-Fi transceiver 208 may normally be maintained in a powered-off condition to conserve battery power, and “selecting” the Wi-Fi transceiver 208 may include powering-on the Wi-Fi transceiver. The Wi-Fi transceiver may then be used to transmit the data, as indicated at 606. After transmission of the data is complete, the Wi-Fi transceiver 208 may then be powered-off, as indicated at 608. The process of
In some embodiments the decision at 602 as to whether to employ high-bandwidth data communication may depend at least in part on the availability of power supply for the mobile communication device. For example, if the mobile communication device is plugged into a wall power outlet (e.g., via an AC to DC power converter, which is not shown) or to an automobile power outlet, and/or if the battery (not shown) of the mobile communication device is relatively fully charged, it may be determined that high-bandwidth data communication is in order, regardless of the nature or quantity of data to be transmitted.
Alternatively, if at 602 a negative determination is made (i.e., if high-bandwidth data communication is not in order), then the mobile device may automatically select, via its control circuit 200, the Bluetooth transceiver 206 for the current data communication needs. In some embodiments the Bluetooth transceiver 206 is normally maintained in a powered-on condition, albeit perhaps in a low power stand-by mode of operation. Selecting the Bluetooth transceiver 206 may include switching the Bluetooth transceiver from a stand-by mode to an active mode of operation. The Bluetooth transceiver may then be used, as indicated at 610, to transmit the data which currently requires transmission. When transmission of the data is complete, the Bluetooth transceiver may then be switched back to a stand-by mode in which address information (including both Bluetooth and Wi-Fi address information) may be exchanged with whatever access point or access points the mobile communication device may be near from time to time.
The above described embodiments have been illustrated in connection with examples in which the mobile communication device is equipped with a Bluetooth transceiver and with a Wi-Fi transceiver. However, in other embodiments, the mobile communication device may be equipped with any two or more types of wireless data communication transceivers and/or transmitters, and access points may be provided to support the types of communication of which the mobile communication device is capable. It may be the case that trade-offs between the two or more transceivers may involve any one or more of such factors as bandwidth, power consumption, range, latency, security and jitter.
In embodiments described above, the mobile communication device communicates with fixed access points. However, in other embodiments, the mobile communication device may communicate with other devices (e.g., in a peer-to-peer communication mode), such as other mobile communication devices and/or desk-top computers with wireless communication capabilities, in addition to or instead of the mobile communication device communicating with fixed access points. Accordingly, the definition of “access point” should be understood to encompass any device with which a mobile communication device communicates by a wireless communication path.
Differences in bandwidth have been discussed herein as a motivation to select between two different transceivers. However, in some embodiments a selection between two different transceivers may be made for other or additional reasons, such as differences in range and/or latency, security, jitter.
In some embodiments, the mobile communication device may permit the user to provide manual input to select between using the Bluetooth and Wi-Fi transceivers. This may be useful, for example, in a case where all of the local access points are Wi-Fi-only devices, in which case the user may manually place the mobile communication device in a mode to use its Wi-Fi transceiver.
The several embodiments described herein are solely for the purpose of illustration. The various features described herein need not all be used together, and any one or more of those features may be incorporated in a single embodiment. Therefore, persons skilled in the art will recognize from this description that other embodiments may be practiced with various modifications and alterations.
