Coexisting radio communication

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/243,069 filed Sep. 16, 2009, the disclosure of which is incorporated by reference herein in its entirety. This application also claims priority to U.S. Provisional Patent Application Ser. No. 61/243,080 filed Sep. 16, 2009, the disclosure of which is incorporated by reference herein in its entirety

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.

Wireless communication devices typically employ multiple radio modules to communicate over multiple wireless networks according to various protocols. These devices often have fewer antennas than radio modules resulting in radio modules timesharing an antenna in order to communicate. A packet or frame communication of a radio module, however, is typically time sensitive and not synchronized with communications of the other radio modules. To communicate a time-sensitive packet or frame, a radio module may access the antenna while another radio module has access for communication. Accordingly, when two or more radio modules attempt to simultaneously communicate via the antenna, communications of one or both radio modules are disrupted resulting in cancelled transmissions, dropped packets, and/or degraded performance as data rates are reduced to compensate for communication errors.

This summary is provided to introduce subject matter that is further described below in the Detailed Description and Drawings. Accordingly, this Summary should not be considered to describe essential features nor used to limit the scope of the claimed subject matter.

A system-on-chip is described that is configured to change a first radio module from a listening mode to a lower power mode to prevent the first radio module from using an exclusive-access period for antenna access effective to increase a nonexclusive-access period, and to grant a second radio module access to the antenna for at least a portion of the increased nonexclusive-access period.

A method is described for receiving an indication of an impending transfer of exclusive access to an antenna currently held by a first radio module to a second radio module, the exclusive access to be held by the second radio module for an amount of time, and responsive to receiving the indication and before the transfer of exclusive access, transmitting a protection frame to a remote entity to cause the remote entity to refrain from transmitting a signal to the first radio module for a portion of the amount of time exclusive access is held by the second radio module.

Another method is described for determining that a communication period of a first radio module will overlap with a periodic transmission time of a second radio module, and responsive to determining that the communication period of the first radio module will overlap with the periodic transmission time of the second radio module, delaying the periodic transmission time of the second radio module until completing the communication period of the first radio module.

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different instances in the description and the figures indicate similar or identical items.

FIG. 1 illustrates an operating environment having wireless communication devices capable of communication in accordance with one or more aspects.

FIG. 2 illustrates a detailed aspect of an example wireless communication device shown in FIG. 1 .

FIG. 3 illustrates a method of coexisting radio communication having a radio module changed from a listening mode to a low-power mode to prevent the radio module from using an exclusive-access period of antenna access.

FIG. 4 illustrates a method of coexisting radio communication having a first radio module transmit a protection frame over an antenna to a remote entity before exclusive access to the antenna is transferred to a second radio module.

FIG. 5 illustrates a method of coexisting radio communication for delaying a periodic transmission of a radio module.

FIG. 6 illustrates a System-on-Chip (SoC) environment for implementing aspects of the techniques described herein.

Conventional techniques for implementing multiple radio modules in a single device may allow a radio module to access an antenna while another radio module is communicating via the antenna. This can disrupt communications of either one or both radio modules. These disruptions of communication result in cancelled transmissions, dropped packets, and/or degraded performance as data rates are reduced to compensate for communication errors. This disclosure describes techniques for coexisting radio communication that reduce or eliminate these disruptions.

The following discussion describes an operating environment, techniques, and apparatuses that may be employed in the operating environment, and a System-on-Chip (SoC) in which components of the operating environment can be embodied. In the discussion below, reference is made to the operating environment by way of example only.

Operating Environment

FIG. 1 illustrates an operating environment 100 having a wireless local area network 102 and a wireless personal area network 104 , each of which include wireless communication devices. Wireless local area network 102 includes a smart-phone 106 , a wireless printer 108 , a tablet computer 110 , a set-top box 112 , and a laptop computer 114 . Personal area network 104 includes smart-phone 106 and a wireless headset 116 . Each of these wireless communication device may transmit and/or receive communications from other devices within its respective network.

Wireless local area network 102 may operate in any suitable mode, such as an ad-hoc or infrastructure mode, providing an independent basic service set or a basic service set, respectively. Wireless personal area network 104 can be configured as a Bluetooth™ pico-net or scatter-net for short-range communication. As shown in FIG. 1 , wireless communication devices, such as smart-phone 106 , may be associated with both networks and communicate with devices of each respective network.

Any of these wireless communication devices may transmit or receive packets and/or frames in accordance with various wireless networking protocols including an Institute of Electronics and Electrical Engineers (IEEE) 802.11 standard, such as 802.11g, 802.11i or 802.11n, or a short-range wireless connectivity standard such as Bluetooth™. In some instances, a wireless communication device may communicate in accordance with more than one protocol, such as smart-phone 106 , which is associated with both networks of FIG. 1 . For example, smart-phone 106 is capable of communicating with wireless headset 116 of wireless personal area network 104 over Bluetooth™ and with wireless printer 108 of wireless local area network 102 over IEEE 802.11n.

FIG. 2 illustrates detailed aspects of an example wireless communication device that corresponds generally to any one of the wireless communication devices shown in FIG. 1 , such as smart-phone 106 . As shown in FIG. 2 , wireless communication device 202 includes a wireless local area network (WLAN) radio module 204 and a wireless personal area network (WPAN) radio module 206 for communicating over different wireless networks and/or protocols. Wireless communication device 202 also includes antenna 208 , which WLAN radio module 204 and WPAN radio module 206 timeshare in order to communicate.

WLAN radio module 204 communicates according at any suitable local area network protocol and/or standard, such as IEEE 802.11g, 802.11i, or 802.11n. Additionally, WLAN radio module 204 can be configured as an access point (AP) implementing a WLAN network for other devices or as a WLAN station, client, or peer within a network of one or more devices. Furthermore, when configured as an AP, WLAN radio module 204 can manage a network and communications within the network by transmitting beacons to other devices, assessing channel congestion, and/or transmitting frames, such as request-to-send (RTS), clear-to-send (CTS), or CTS-to-self (CTS2Self) frames.

WPAN radio module 206 communicates according to any suitable personal area network protocol such as Bluetooth™, and may be configured as a master or slave device within a pico-net. As a master device, WPAN radio module 206 can establish a Bluetooth™ pico-net and manage traffic within the pico-net. Traffic within the pico-net includes synchronous traffic such as synchronous connection oriented (SCO) or enhanced SCO (eSCO) link traffic which consists of periodic time periods or slots for exchanging packets. Packets can be exchanged with a slave device by WPAN radio module 206 during these time slots, such as, audio, link management, or data packets.

In addition to SCO traffic, WPAN radio module 206 can communicate packets over an asynchronous connectionless link (ACL) to other devices. As a master device, WPAN radio module 206 can indicate to a slave device that asynchronous data is destined to a subsequent slave time slot. As a slave device, however, WPAN radio module 206 listens to master time slots to determine if a master device will communicate asynchronous data during the a following time slot(s). Packets exchanged during ACL exchanges can include any suitable type such as link manager protocol (LMP) packets or advanced audio distribution profile (A2DP) packets.

Antenna 208 is accessed by WLAN radio module 204 and/or WPAN radio module 206 in order to communicate. Access to antenna 208 may be via an antenna switch (not shown) or any other suitable method. WLAN radio module 204 and WPAN radio module 206 can each include a communication manager 210 , which can be embodied separately or distinctly on each respective radio module. In some instances, communication manager 210 is integrated with wireless communication device 202 and communicatively coupled to either one or both radio modules and/or an antenna switch (not shown).

Communication manager 210 (in one aspect) includes a set of computer-executable instructions stored on computer-readable storage media 212 . When executed by one or more processors 214 , a component on which communication manager 210 is embodied acts according to those instructions. Communication manager 210 acts independently and/or in conjunction with various other entities of wireless communication device 202 , such as being firmware integrated into a System-On-Chip having or communicating with WLAN radio module 204 and/or WPAN radio module 206 .

Techniques of Coexisting Radio Communication

The following discussion describes techniques of coexisting radio communication. These techniques can be implemented using the previously described environment, such as by communication manager 210 of FIG. 2 embodied on WLAN radio module 204 , WPAN radio module 206 , and/or wireless communication device 202 . These techniques include methods illustrated in FIGS. 3 , 4 , and 5 , each of which is shown as a set of operations performed by one or more entities. These methods are not necessarily limited to the orders shown for performing the operations. Further, these methods may be used in conjunction with one another whether performed by the same entity, separate entities, or any combination thereof. In portions of the following discussion, reference will be made to operating environment 100 of FIG. 1 by way of example. Such reference is not to be taken as limited to operating environment 100 but rather as illustrative of one of a variety of examples.

FIG. 3 depicts a method 300 for coexisting radio communication, including operations performed by communication manager 210 of FIG. 2 .

At 302 , a first radio module is changed from a listening mode to a low-power mode. The listening mode includes alternating periods of exclusive access and nonexclusive access. During exclusive-access periods the first radio module has exclusive access to an antenna. Changing the first radio module to a low-power mode prevents the first radio module from using an exclusive-access period to obtain access to the antenna. Preventing the first radio module from using an exclusive-access period increases a nonexclusive-access period.

As an example, consider smart-phone 106 having WPAN radio module 206 configured as a Bluetooth™ slave device listening via antenna 208 for an asynchronous communication from wireless headset 116 configured as a Bluetooth™ master device. Communication manager 210 can change WPAN radio module 206 to a sniff mode, a periodic low-power mode that allows a Bluetooth™ slave device, WPAN radio module 206 in this case, to listen while in an active state. While in an inactive or low-power state, however, WPAN radio module 206 conserves power waiting until the next active state period to listen for asynchronous communication.

In some instances, parameters of the sniff mode can be configured to adjust a duty cycle of the periodic active states for a slave device. The configuration of the parameters of the sniff mode can be based on any suitable data, such as user input or an estimated bandwidth requirement for a radio. In the context of the present example, assume smart-phone 106 is receiving an audio stream that requires approximately 20% of a bandwidth available over antenna 208 .

Communication manager 210 can configure parameters of the sniff mode for WPAN radio module 206 of smart-phone 106 for an active-period duty cycle for approximately 20-25% of available antenna access. Here assume an asynchronous communication cycle for WPAN radio module 206 includes 24 time slots, communication manager 210 can configure the sniff mode for an active state of six time slots and a low-power state for eighteen time slots.

At 304 , a second radio module is granted access to the antenna to allow the second radio module to communicate via the antenna. The second radio module may use some or the entire amount of the increased time of a nonexclusive-access period of the first radio module. A time required for the second radio module to communicate may be more than the typical nonexclusive-access period of the first radio module, in such a case, increasing the nonexclusive-access periods of the first radio module allows the second radio module to communicate and/or complete packet exchanges.

Continuing the present example, communication manager 210 grants WLAN radio module 204 of smart-phone 106 access to antenna 208 to communicate with wireless printer 108 for the remaining 75% (18 time slots) of the bandwidth while the WPAN radio module 206 is in a low-power state of the sniff mode.

Optionally, at 306 , the grant of the second radio module's access to the antenna is ceased. In some cases, the low-power mode of the first radio module may be periodic, and ceasing to grant access of the second radio module may be responsive to the first radio module exiting the low-power mode. In other cases, prior to ceasing the grant, the second radio module may transmit a protection frame, such as a CTS-to-self frame, to prevent a remote entity from transmitting a signal to the second radio module for at least a portion of a subsequent exclusive-access period of the first radio module. In such a case, the first radio module's exclusive-access periods for communication via the antenna may be limited to a certain amount of time or number of timeslots based on an effective duration of a suitable protective frame.

Continuing the present example, communication manager 210 ceases to grant WLAN radio module 204 access to antenna 208 responsive to WPAN radio module 206 exiting the low-power state of the sniff mode. WPAN radio module 206 can then listen and/or communicate with wireless headset 116 during the six time slots of the active state of the sniff mode.

Optionally, at 308 , the first radio module is changed from the low-power mode back to the listening mode. Concluding the present example, communication manager 210 changes WPAN module 206 of smart-phone 106 back to an ACL communication listening mode to actively listen for asynchronous communication from wireless headset 116 . Operations of blocks 302 , 304 , 306 , and/or 308 may be repeated allowing the first and second radio modules to communicate additional data as described above.

FIG. 4 depicts a method 400 for coexisting radio communication, including operations performed by communication manager 210 of FIG. 2 .

At 402 , an indication of an impending transfer of exclusive access to an antenna currently held by a first radio module to a second radio module is received. The indication may also indicate an amount of time that exclusive access is to be held by the second radio module. This indication may be received from the second radio module, which is preparing to communicate during a synchronous period. For example, a WPAN radio module 206 of smart-phone 106 may indicate to communication manager 210 a SCO period of 1.25 ms is approaching.

At 404 , a protection frame is transmitted to a remote entity that is capable of transmitting a signal to the first radio module. In some cases, the protection frame is effective to cause the remote entity to refrain from transmitting a signal to the first radio module during the second radio module's exclusive access. The protection frame can be any suitable frame or combination of frames, such as a CTS-to-self, RTS and/or CTS frame(s).

Parameters of the protection frame can be based on the amount of time that exclusive access to the antenna is to be held by the second radio module. For instance, a CTS-to-self frame may indicate a length of time that corresponds to a period of Bluetooth SCO traffic, effective to prevent remote WLAN devices from transmitting during Bluetooth communications.

In some instances, the first radio may transmit data after transmission of the protection frame until the start of the second radio module's exclusive access to increase throughput. Data frames transmitted after the protection frame can be transmitted using point coordination function inter-frame spacing (PIFS) or without back-off. In some cases, the transmitted data frames may carry remaining protection time of the transmitted protection frame. Alternately or additionally, the transmitted data frames may carry an expiry value ending the data transmission before the second radio module's exclusive access.

While exclusive access to the antenna is held by the second radio module, the first radio module may be set to a low-power mode. Additionally or alternately, the first radio module can compress data queued for transmission for the amount of time that exclusive access is held by the second radio module. Continuing the present example, communication manager 210 can cause WLAN radio module 204 to transmit a CTS-to-self frame indicating 1.25 ms of medium unavailability to wireless printer 108 to prevent wireless printer 108 from transmitting during the SCO period of WPAN radio module 206 . Additionally, communication manager 210 can set WLAN radio module 204 to a low-power state during the SCO period of WPAN module 206 to conserve power.

Optionally, at 406 , a frame is transmitted to a remote entity effective to allow the remote entity to communicate with the first radio module. Any suitable frame may be transmitted such as, for example, a contention-free end (CF-End) frame. Transmitting the frame to allow the remote entity to communicate may be responsive to determining that the second radio module has ceased holding exclusive access to the antenna. Concluding the present example, communication manager 210 causes WLAN radio module 204 to transmit a CF-End frame to wireless printer 108 , allowing communication to resume. The operations of blocks 402 , 404 , and 406 may be repeated allowing both radio modules to communicate additional data.

FIG. 5 depicts a method 500 for coexisting radio communication, including operations performed by communication manager 210 of FIG. 2 .

At 502 , it is determined that a communication period of a first radio module will overlap a periodic transmission of a second radio module. In some instances, alternating communication and non-communication periods of the first radio module are not synchronized with periodic transmissions of the second radio module. Or the communication period may be a synchronous communication period, such as a period for SCO or eSCO traffic. Additionally, the periodic transmission can be a beacon transmission for a WLAN network scheduled for a target beacon transmission time (TBTT). In this case, communication manager 210 may determine that a SCO period of WPAN radio module 206 will overlap a TBTT of WLAN radio module 204 .

At 504 , the periodic transmission of the second radio module is delayed until after the communication period of the first radio module. Delaying the periodic transmission can be responsive to determining that the communication period of the first radio module will overlap the periodic transmission of the second radio module. In some instances, a signal can be asserted to the second radio module effective to delay the periodic transmission. The asserted signal may indicate that a communication channel or medium is restricted, such as a clear channel assessment (CCA) signal. In the context of the present example, communication manager 210 asserts a CCA signal of WLAN radio module 204 to delay transmission of the beacon scheduled for the TBTT until after the SCO period of WPAN radio module 206 .

At 506 , delaying the periodic transmission of the second radio module is ceased to allow the second radio module to transmit. Ceasing to delay the periodic transmission is responsive to the communication period of the first radio module ending or to a time-out period lapsing. Ceasing to delay the periodic transmission can include ceasing to assert a signal to the second radio module such as, for example, the CCA signal as described above. Concluding the present example, communication manager ceases to assert the CCA signal to WLAN module 204 to allow transmission of the beacon after the SCO period of WPAN radio module 206 . The operations of blocks 502 , 504 , and 506 may be repeated allowing both radio modules to communicate additional data.

System-on-Chip

FIG. 6 illustrates a System-on-Chip (SoC) 600 , which can implement various embodiments described above. A SoC can be implemented in a fixed or mobile device, such as a computing device, game console, camera, wireless printer, wireless headset, smart phone, digital video recorder, picture frame, set-top box, and/or any other type of device that may communicate with multiple wireless networks.

SoC 600 can be integrated with electronic circuitry, a microprocessor, memory, input-output (I/O) logic control, communication interfaces and components, other hardware, firmware, and/or software needed to run an entire device. SoC 600 can also include an integrated data bus (not shown) that couples the various components of the SoC for data communication between the components. A wireless communication device that includes SoC 600 can also be implemented with many combinations of differing components.

In this example, SoC 600 includes various components such as an input-output (I/O) logic control 602 (e.g., to include electronic circuitry) and a microprocessor 604 (e.g., any of a microcontroller or digital signal processor). SoC 600 also includes a memory 606 , which can be any type of random access memory (RAM), a low-latency nonvolatile memory (e.g., flash memory), read only memory (ROM), and/or other suitable electronic data storage. SoC 600 can also include various firmware and/or software, such as an operating system 608 , which can be computer-executable instructions maintained by memory 606 and executed by microprocessor 604 . SoC 600 can also include other various communication interfaces and components, wireless communication components, other hardware, firmware, and/or software.

SoC 600 also includes WLAN radio module 204 , WPAN radio module 206 , and communication manager 210 . Examples of these various components, functions, and/or entities, and their corresponding functionality, are described with reference to the respective components of the environment 100 shown in FIG. 1 . Soc 600 can also include an antenna switch 610 to allow WLAN radio module 204 and WPAN radio module 206 to timeshare access to an antenna or other medium.

Communication manager 210 in SoC 600 , either independently or in combination with other entities, can be implemented as computer-executable instructions maintained by memory 606 and executed by microprocessor 604 to implement various embodiments and/or features described herein. Communication manager 210 may also be provided integral with other entities of the SoC, such as integrated with one or both of WLAN radio module 204 and/or WPAN radio module 206 , antenna switch 610 , or an arbiter module (not shown). Alternatively or additionally, communication manager 210 and the other components can be implemented as hardware, firmware, fixed logic circuitry, or any combination thereof that is implemented in connection with the I/O logic control 602 and/or other signal processing and control circuits of SoC 600 .

Although the subject matter has been described in language specific to structural features and/or methodological operations, the subject matter defined in the appended claims is not necessarily limited to the specific features or operations described above, including orders in which they are performed.