Dual antenna topology for Bluetooth and IEEE 802.11 wireless local area network devices

A method includes determining that an antenna shared between a Bluetooth transceiver and a WLAN transceiver is available to the WLAN transceiver based on an activity signal associated with the Bluetooth transceiver. Access to the shared antenna is provided to the WLAN transceiver based on the determination, and the WLAN transceiver is configured to use diversity in transacting WLAN signals via a plurality of antennas, including the shared antenna. Access to the shared antenna is transferred from the WLAN transceiver to the Bluetooth transceiver based on the activity signal.

TECHNICAL FIELD

This description relates to wireless communication networks and more particularly to a dual antenna topology for use in such a network.

BACKGROUND

The use of Wireless Personal Area Networks (WPANs) has been gaining popularity in a great number of applications because of the flexibility and convenience in connectivity they provide. WPAN systems, such as those based on Bluetooth (BT) technology, replace cumbersome cabling and/or wiring used to connect peripheral devices and/or mobile terminals by providing short distance wireless links that allow connectivity within a short (e.g., 10-meter) range. In contrast to WPAN systems, Wireless Local Area Networks (WLANs) provide connectivity to devices that are located within a larger geographical area, such as the area covered by a building or a campus, for example. WLAN systems based on IEEE 802.11 standard specifications, typically operate within a 100-meter range, and are generally utilized to supplement the communication capacity provided by traditional wired Local Area Networks (LANs) that are installed in the same geographic area as the WLAN system.

In some instances, WLAN systems may be operated in conjunction with WPAN systems to provide users with an enhanced overall functionality. For example, Bluetooth technology may be utilized to connect a laptop computer or a handheld wireless terminal to a peripheral device, such as a keyboard, mouse, headphone, speaker, and/or printer, while the laptop computer or the handheld wireless terminal is also connected to a WLAN network through an access point (AP) located within the building.

Both Bluetooth and WLAN radio devices, such as those used in, for example, handheld wireless terminals, generally operate in the 2.4 GHz (2.4000-2.4835 GHz) Industrial, Scientific, and Medical (ISM) unlicensed band. Other radio devices, such as those used in cordless phones, may also operate in the ISM unlicensed band. While the ISM band provides a suitable low-cost solution for many of short-range wireless applications, it may also have some drawbacks when multiple users or devices operate simultaneously within the band in a small geographic area. For example, because of the limited bandwidth, spectrum sharing may be necessary to accommodate multiple users. Multiple active users may also result in significant interference between operating devices. Moreover, in some instances, microwave ovens may also operate in this frequency spectrum and may produce significant interference or blocking signals that may affect Bluetooth and/or WLAN transmissions.

It may be that a single device, such as a laptop, may perform both WLAN and Bluetooth transactions. In such a situation not only does the problem of potential interference arise, but also due at least in part to the specifications (e.g., size and power consumption) of the device, WLAN and Bluetooth radio devices (e.g., transceivers) may share one or more antennas. It may then be desirable that when a shared antenna is idle (e.g., due to the inactivity of a radio device, such as the Bluetooth radio device), it may be accessible to another radio device (e.g., the WLAN radio device) to increase throughput and/or reliability associated with the wireless transactions.

SUMMARY

In a first general aspect, a system includes a first antenna, a second antenna, a Bluetooth transceiver, WLAN transceiver, and an antenna control processor. The Bluetooth transceiver is configured to transmit Bluetooth signals and to receive Bluetooth signals via one of the antennas. The WLAN transceiver is configured to transmit and receive WLAN signals via one or both of the antennas. The antenna control processor configured to operatively couple the second antenna to the Bluetooth transceiver to transmit Bluetooth signals and configured to operatively couple the second antenna to the WLAN transceiver when Bluetooth signals are not transmitted, thereby allowing the WLAN transceiver to utilize diversity associated with transmitting or receiving the WLAN signals via the first and second antennas.

In another general aspect, a method includes receiving one or more signals associated with a first transceiver via a plurality of antennas, where the first transceiver is configured to use diversity associated with the transmission or reception of the signals via two or more of the plurality of antennas. It is determined, based on an activity of a second transceiver, that the second transceiver requires access to one or more of the antennas shared between the first transceiver and the second transceiver, and access is transferred to one or more of the shared antennas from the first transceiver to the second transceiver based on the determination.

In another general aspect, a method includes determining that an antenna shared between a Bluetooth transceiver and a WLAN transceiver is available to the WLAN transceiver based on an activity signal associated with the Bluetooth transceiver. Access to the shared antenna is provided to the WLAN transceiver based on the determination, and the WLAN transceiver is configured to use diversity in transacting WLAN signals via a plurality of antennas, including the shared antenna. Access to the shared antenna is transferred from the WLAN transceiver to the Bluetooth transceiver based on the activity signal. The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

DETAILED DESCRIPTION

FIG. 1is a block diagram of an example system100for a dual antenna topology, according to an example embodiment. In the example ofFIG. 1, the system100may coordinate and/or arbitrate access to one or more antennas shared between two or more radio devices/transceivers. This may allow for example, a first transceiver to transact (e.g., transmit and/or receive) wireless signals via either and/or both antennas, while the second radio device is idle or otherwise inactive, thus allowing the first radio device to benefit from diversity of different antenna options when transacting (e.g., receiving and/or transmitting) a wireless communication, thus improving the reliability and/or throughput of the transacted signals.

The system100may include a Wireless Local Area Network (WLAN) transceiver102configured to transmit and/or receive WLAN packets, frames, and/or other signals. The WLAN transceiver102may include for example a WiFi radio device configured to transmit and receive WLAN packets over one or more ports. The WLAN transceiver102may comprise suitable logic, circuitry and/or code to support WLAN protocol signals and/or packets for communication. As shown in the example ofFIG. 1, the WLAN transceiver102may include a single port (e.g., Tx) for packet transmissions and two separate ports (e.g., Rx1 and Rx2) for packet receipt. In other example embodiments, the WLAN transceiver102may include additional and/or different ports, including for example a port configured for both WLAN packet transmission and reception. For example, the Rx2 port may be replaced with a Tx/Rx port whereby the WLAN transceiver102may be configured to transmit and receive WLAN signals via the Tx/Rx port.

The system100may include a Bluetooth (BT) transceiver104configured to transmit and/or receive BT packets, frames and/or other signals. The BT transceiver104may include for example a BT radio device. The BT transceiver104may comprise suitable logic, circuitry and/or code to support BT protocol signals and/or packets for communication. As shown in the example ofFIG. 1, the BT transceiver104may include a single port for packet transmission and receipt (e.g., Tx/Rx). In other example embodiments, the BT transceiver104may include additional and/or different ports, including for example separate packet transmission and receipt ports.

Antenna1106A may include a broadband antenna. Antenna1106A may be configured to communicate via an Industrial, Scientific, Medical (ISM) band. For example, antenna1106A may be configured to receive and/or transmit packets across a channel within the 2.4-2.4835 GHz frequency band. In the example ofFIG. 1, antenna1106A may include an antenna dedicated to the transmission and receipt of WLAN packets. In other example embodiments, antenna1106A may be configured to transmit and/or receive other protocol packets, such as BT packets in addition to and/or in lieu of the WLAN packets, similar to antenna2106B as discussed below.

Antenna2106B may be substantially similar to antenna1106A, except in that rather than being dedicated for use by a single radio device or transceiver, use of antenna2106B may be shared by two or more radios or transceivers. For example, the system100may be configured such that the WLAN transceiver102uses antenna2106B to receive WLAN packets and a BT transceiver104uses antenna2106B to transmit and/or receive BT packets. In other example embodiments antenna2may be configurable for different wireless transactions in addition to and/or different from those shown in the example system100. For example, in another example embodiment, the WLAN transceiver102may use antenna2106B to transmit WLAN packets. An example of sharing a single antenna by two or more communication protocols may include the method and system for sharing a single antenna as described in U.S. patent application Ser. No. 11/143,378, filed Jun. 2, 2005, titled “Method and system for sharing a single antenna on platforms with collocated bluetooth and IEEE 802.11B/G devices,” which is incorporated by reference herein for all purposes. Antenna2106B is located within the system100at a remote distance from antenna1106A, so that the two antennas have the possibility of being exposed to different electromagnetic spectra of the radiation they are adapted to receive. For example, antenna2106B can be located at a distance from antenna1106A that is more than half a wavelength of the radiation that the antennas are adapted to receive, so that antennas might be located in different interference nodes of the radiation. For example, antennas adapted to receive Bluetooth and WLAN signals having a frequency of about 2.4 GHz may be located at more than about 3 or 6 centimeters from each other. Thus, if antenna1is located in an anti-node of the radiation such that it receives a weak signal, antenna2might be located in a node and receive a stronger signal.

Switch1108A may include a device configured to change the course or flow of a circuit or other current. Switch1108A may be a single pole, dual throw (SPDT) switch. Switch1108A may be used for example, to determine whether antenna1106A is set to transmit or receive WLAN packets for processing by the WLAN transceiver102. In the example ofFIG. 1, switch1108A is shown in a position such that antenna1106A may be used by WLAN transceiver102to receive WLAN packets. When toggled however, switch1108A may allow the WLAN transceiver102to transmit WLAN packets via antenna1106A.

Switch2108B may be similar or substantially similar to switch1108A, and may also be a SPDT switch. Antenna2106B may be set either to transmit and receive BT packets or to receive WLAN packets dependent on the position of switch2108B. In the example ofFIG. 1, switch2108B, as shown, is in a position such that the BT transceiver104may use antenna2106B to transmit and receive BT packets. In another possible position of the switch2108B evident fromFIG. 1, the WLAN transceiver102may receive WLAN signals (or packets) via antenna2106B. In other example embodiments, switch1108A and/or switch2108B may include multiple throw and/or SPDT switches and may be used to set to different and/or additional antenna configuration options, and may include multiple switch settings (in addition to and/or different from the two shown in the example ofFIG. 1).

An antenna control processor (ACP)110may determine and/or toggle switches to set the configuration of one or more antennas. For example, the ACP110may determine whether or not to activate and/or otherwise toggle the switches (106A and106B), thus determining how antenna1106A and antenna2106B are configured to operate relative to the WLAN and BT transceivers (e.g.,102and104, respectively). For example, the ACP110may toggle switch2108B from its current position as shown in the example ofFIG. 1where antenna2106B is set to transact BT packets for processing by the BT transceiver104, such that antenna2106B may be set to receive WLAN packets for processing by the WLAN transceiver102.

The ACP110may control the state of switch2108B, based at least in part on a BT_ACTIVE signal112. When the BT transceiver104is ready to transmit/receive and/or is transmitting/receiving one or more BT signals, it may assert the BT_ACTIVE signal112. Then, when the BT transceiver104has completed the transmission/reception of one or more BT signals, the BT transceiver104may deassert the BT_ACTIVE signal112. The BT_ACTIVE signal112may indicate (e.g., to the WLAN transceiver102and/or ACP110) when the BT transceiver104is using and/or is ready to use antenna2106B to transact (e.g., transmit and/or receive) BT packets.

According to an example embodiment, the WLAN transceiver102may fast poll the BT transceiver104to determine whether the BT_ACTIVE signal112is being asserted. Then for example, the WLAN transceiver102, upon determining that the BT_ACTIVE signal112is being asserted, may terminate (e.g., with an interrupt) and/or otherwise complete its current WLAN packet reception (via the Rx2 port). According to an example embodiment, the WLAN transceiver102, after determining that the BT_ACTIVE signal112is present (or being asserted), may set a flag indicating that the BT transceiver104is currently active. Then for example, upon a determination that the BT_ACTIVE signal112is no longer present or being asserted, the WLAN transceiver102may begin receiving WLAN signals via antenna2106B (after switch2108B has been set for WLAN packet reception by the ACP110).

As just referenced, the BT_ACTIVE signal112may include a signal asserted by the BT transceiver104which may be received or determined by the WLAN transceiver102(and/or ACP110) to indicate that the BT transceiver104is ready to and/or is in the process of transacting one or more BT packets. For example, the BT transceiver104may transmit a first BT packet then wait for a period of time before transmitting a second packet. During transmission of the first packet, the BT transceiver104may generate, provide or otherwise assert the BT_ACTIVE signal112, which may be determined or received by the WLAN transceiver102and/or the ACP110. Then, for example, during the time period between transmissions, the BT transceiver104may discontinue, deactivate and/or otherwise de-assert the BT_ACTIVE signal112. Then for example, during the time the BT_ACTIVE signal112is inactive or is de-asserted, the ACP110may toggle or otherwise activate switch2108B into a state wherein antenna2106B may be set to receive WLAN packets and provide the packets to the WLAN transceiver102. Then for example, when the BT_ACTIVE signal112is asserted, the ACP110may toggle the switch2108B into a state whereby the antenna2106B may be set to transact BT packets and in which the antenna2106B does not provide signals to the WLAN transceiver102.

According to an example embodiment, the BT_ACTIVE signal112may cause the WLAN transceiver102to set a signal, flag and/or interrupt. For example, when the WLAN transceiver102determines that the BT transceiver104is asserting the BT_ACTIVE signal112, the WLAN transceiver102may set an interrupt which may cause the immediate cessation of the receipt of any WLAN signals by the WLAN transceiver102via antenna2106B. Or for example, a determination of an asserted BT_ACTIVE signal112may cause the WLAN transceiver102to set a flag indicating the assertion of the BT_ACTIVE signal112. The status of the flag may cause the ACP110to toggle switch2108B such that the antenna2106B may either be set to receive WLAN packets or transmit/receive BT packets. For example, a set flag may cause the ACP110to set the switch2108B, as shown in the example ofFIG. 1, to the BT transceiver104. In another example embodiment the ACP110may directly determine whether the BT_ACTIVE signal112is being asserted.

The BT_ACTIVE signal112may be associated with a guard time. The guard time may include a time period by which the WLAN transceiver102is to terminate and/or complete the current signal receipt (if any) and the ACP110is to toggle switch2108B such that antenna2106B is set to BT transceiver104. For example, the guard time may be 0.02 ms. Then for example, upon a determination of an asserted BT_ACTIVE signal112, the ACP110is to toggle switch2108B within 0.02 ms such that antenna2106B is set to transact BT packets. Then for example, the WLAN transceiver102may store the status of the WLAN packet receipt at the expiration of the guard time, such that the WLAN transceiver102may make a determination on how to proceed with WLAN packet processing based at least in part on the status. For example, the WLAN packet receipt via antenna2106B may be terminated prior to the receipt of a complete WLAN packet. Then for example, the WLAN transceiver102may determine that the WLAN packet from antenna1106A should be used and that diversity should not be implemented with the incomplete packet (as received via antenna2106B).

According to an example embodiment, the BT_ACTIVE signal112, the BT transceiver104and/or the WLAN transceiver102may be associated with priorities such that upon a determination of an asserted BT_ACTIVE signal112, the system100(e.g., the BT transceiver104, ACP110and/or WLAN transceiver102) may compare the relative priorities associated with the WLAN transceiver102and/or the BT transceiver104to determine which transceiver gets access to the antenna2106B.

For example, if the BT transceiver104transmits and/or receives BT voice packets that do not include error correction or retransmit capability, then the transmission and reception of the BT voice packets may include or be provided with the highest priority, wherein upon receipt of the BT_ACTIVE signal112, the ACP110may immediately toggle switch2108B to set antenna2106B to BT transceiver104so as to avoid packet dropping and/or other errors associated with the transmission and/or receipt of BT voice packets. The ACP110and/or the WLAN transceiver102may, for example, interrupt the current WLAN transaction upon determination of an asserted BT_ACTIVE signal112. In other example embodiments, the ACP110may not toggle switch2108B to receive WLAN signals if a priority associated with the BT signals is high enough.

According to another example embodiment, the BT transceiver104may transmit and/or receive BT data packets that are configured with error correction. For example, unlike BT voice packets which may need to be transmitted in real-time, BT data packets may be able to be buffered and thus may include error correction not included with BT voice packets. Then for example, the BT data packets may be associated with a lower priority than BT voice packets and/or some WLAN transceiver102transmission/receipt functions. Then for example, upon determination of the BT_ACTIVE signal112, the priority of a competing WLAN packet to be received may be compared with the priority associated with the BT data packet, and the BT transceiver104may be, at least temporarily, denied access to antenna2106B based on a higher priority associated with a WLAN packet being transacted.

When both antenna1106A and antenna2106B are set to transact WLAN packets, the WLAN transceiver102may apply diversity (using diversity logic114) to transact the WLAN packets. For example, the WLAN transceiver102may receive WLAN packets via both antenna1106A and antenna2106B, whereby the diversity logic114may be applied to the received packets.

The diversity logic114may include logic configured to apply, perform, implement or otherwise employ a diversity scheme with transacted WLAN packets, such as receive diversity on received WLAN signals. Receive diversity may include an algorithm or scheme for improving reliability of a message or signal by utilizing two or more communication channels with different characteristics. Diversity, including receive diversity, may combine the signals received via two or more antennas to account for different signal strength on each antenna and/or different phases of the signal at the different antenna. For example, receive diversity, as employed by the diversity logic114may utilize both antenna1106A and antenna2106B, whereby the two antennas are physically located in different locations. The different locations may result in antenna1106A and antenna2106B receiving identical signals from the same source, however the signals, as received by the different antennas, may have different strengths or phases because of the different locations of the antennas. For example, one antenna may be located at a node of the signal while another antenna may be located at an anti-node. Then for example, the WLAN transceiver102may then use diversity logic114to receive a stronger and/or more reliable signal or packet.

Receive diversity may include selection diversity and/or combination diversity. Selection diversity may include multiple versions of the same signal being received, whereby the stronger signal may be selected. In the example ofFIG. 1, with selection diversity, both antenna1106A and antenna2106B (when set to receive WLAN packets) may receive the same or similar WLAN signals. Then for example, diversity logic114may determine which of the packets are stronger and/or more reliable and may opt to receive the stronger signal in lieu of the other weaker signal.

With combination diversity, a first portion of a first WLAN packet may be received by antenna1106A and a second portion of the first WLAN signal may be received by antenna2106B. Diversity logic114, may then for example, combine the first portion from antenna1106A and the second portion of the signal from antenna2106B to result in a receipt of the first WLAN packet.

While the diversity logic114is referred to mainly in the context of receiving packets over two or more antennas, it is to be appreciated that the diversity logic114may also be applied in transmitting packets over two or more antennas. For example, the WLAN transceiver102may be configured to transmit and receive via both antenna1106A and antenna2106B. Then for example, when both switch1108A and switch2108B are set to allow the WLAN transceiver102to transmit WLAN packets (e.g., when the BT_ACTIVE signal112is not being asserted), then the WLAN transceiver102may use the diversity logic114to transmit WLAN packets via antenna1106A and antenna2106B using selection and/or combination diversity during the transmissions.

According to an example embodiment, the WLAN transceiver102and the BT transceiver104may be installed in close proximity to one another. For example, WLAN transceiver102and the BT transceiver104may be installed on a circuit board of a telephony and/or network device, such as, for example, a laptop or desktop computer. As discussed above, antenna1106A and antenna2106B may include broadband antennas configured to receive signals and/or energy across a wide spectrum (e.g., between 2.4-2.5843 GHz). Then for example, if the BT transceiver104is transmitting BT packets via antenna2106B while the WLAN transceiver102is receiving WLAN packets via antenna1106A, antenna1106A may receive at least a portion of the energy associated with the transmission of the BT packets via antenna2106B. The receipt of the BT signal(s) at antenna1106A (e.g., the antenna receiving WLAN packets) may result in the desensitization of the WLAN transceiver102to WLAN signals (i.e., receiver desensitization).

Receivers may be configured to receive both strong and weak signals based for example on a baseline signal strength. The further below the baseline signal strength an incoming signal is (i.e., the weaker the incoming signal), the more likely the signal is to be interpreted as noise (i.e., unintentionally received energy) and discarded. If for example, over time the receiver receives very strong signals, then the baseline signal strength of the receiver may recalibrate and increase, or for example if the receiver was to receive very weak signals, the baseline signal strength may likewise fall.

If a transmitter and a receiver are placed in close proximity to one another, then there may be an increased likelihood that the receiver will receive at least a portion of the energy emitted by the transmitter during transmission. This unintentional energy reception may result in the receiver becoming desensitized and the baseline signal strength increasing. Then for example due to the increased baseline signal strength, the receiver may be unable to distinguish between a weak signal from the intended source or transmitter and the strong unintentional noise reception from the proximate or unintentional transmitter.

In the example ofFIG. 1, when the BT transceiver104is transmitting while the WLAN transceiver102is receiving, if there is not enough isolation between the BT transceiver104and the WLAN transceiver102, then the WLAN transceiver102may receive and become overwhelmed by the BT signal (e.g., energy received from the BT transmission(s) by the BT transceiver104) and may become desensitized to the WLAN signal that it is trying to receive. Consequently, the signal transmission and receipt functions between the WLAN transceiver102and BT transceiver104may be arbitrated to prevent or otherwise reduce the likelihood of receiver desensitization.

Greater isolation between two or more radios or transceivers may be achieved for example by increasing the distance between a transmitter and receiver, and by employing shielding and/or controlling the polarization of the two signals emitted by the two antennas. If sufficient isolation is achieved between the WLAN transceiver102and BT transceiver104, then for example, the transmissions and receptions between the WLAN102and BT transceiver104may not have to be arbitrated (i.e., one transceiver need not be prevented from receiving signals while the other is transmitting signals, or vice versa) to avoid receiver desensitization.

If sufficient isolation is achieved, then for example, the BT transceiver104may employ adaptive frequency hopping (AFH) without additional arbitration. AFH logic116may be configured to avoid collisions between the transmissions and/or receipt of packets between a BT radio and another radio or transceiver. For example, the AFH logic116may be employed by the BT transceiver104to avoid collisions between the transmission/receipt of BT packets and the transmission/receipt of WLAN packets.

A collision (or interference) may occur for example when two or more radios/transceivers are attempting to transmit and/or receive packets within the same frequency band. For example, as discussed above, the antennas (106A and106B) may be broadband antennas capable of transmitting/receiving packets across a wide 2.4-2.5 GHz frequency. Then, for example, of the potentially available 100 MHz, a first radio may only need a specified 20 MHz on which to transmit/receive packets. If however, a second radio transmits and/or receives packets within the same 20 MHz frequency band being used by the first radio, then interference or collisions may occur.

The AFH logic116may be configured to avoid such collisions/interference for example, by determining whether a frequency band is occupied before transacting (e.g., transmitting and/or receiving) packets. For example, the AFH logic116may listen for background noise on different potential transmission channels (or bands) and choose the channel with the lowest noise on which to transmit and/or receive packets. Then for example, if the AFH logic116determines that a frequency band is occupied (e.g., by the WLAN transceiver102), it may “hop” to the next available frequency band (e.g., next channel with lowest noise) before transmitting/receiving packets, thus avoiding collisions/interference.

As discussed above, if sufficient isolation is not achieved between the WLAN transceiver102and the BT transceiver104then the transactions by the receivers may be arbitrated to avoid receiver desensitization and if sufficient isolation is achieved then a system may be able to implement AFH only (e.g., without arbitration). However, in example embodiments, it may be difficult to determine ahead of time (e.g., prior to building at least a prototype of an embodiment), whether sufficient isolation will exist between a WLAN transceiver and BT transceiver (e.g.,102and104, respectively). A system (e.g.,100) however may be implemented into a prototype whereby the decision whether or not to implement arbitration may be made after the system is designed and built, as the logic associated with arbitration and/or AFH may be software based, thus allowing a manufacturer in greater flexibility in system design.

In other example embodiments where it may be difficult to determine whether sufficient isolation exists to prevent receiver desensitization, an embodiment may be configured to operate with an acceptable amount of desensitization, and/or an embodiment may perform some functions that are better suited to the system (e.g.,100) implementing AFH logic116only (e.g., where isolation is found to be sufficient) and other functions that are better suited to the system implementing both arbitration and AFH logic116(e.g., when isolation may be insufficient). In these example embodiments, a host processor (not shown) may determine and/or switch between implementing AFH logic116and/or arbitration.

For example, with WLAN web browsing, file transfer protocol (FTP) and/or BT synchronization (e.g., of an address book and calendar on a personal digital assistant (PDA)), an embodiment may tolerate some desensitization and packet loss and still achieve better averaged throughputs with AFH only than with using arbitration, even though there may be occasional packet loss that may require retransmission of either or both BT and WLAN packets. In other situations, that may require minimal packet loss or low latency (e.g., voice-over WLAN, voice-over BT, or Synchronous Connection Oriented (“SCO”) link BT communications), maximizing averaged throughput may not be as important as avoiding collisions between BT and WLAN packets to avoid packet loss and retransmission. In such cases arbitration may be used in addition to or instead of AFH logic116. Then, for example, the host processor may determine when to implement AFH only and when to implement arbitration (with or without AFH). This determination may then be received by a monitor circuit118.

The monitor circuit118may receive a determination about whether to implement AFH only or arbitration (with or without AFH) and may provide the determination to the coexistence interface120. For example, as discussed above, a host processor may, based on a determination either that there is enough isolation between a transmitter and receiver such that the likelihood of receiver desensitization occurring is acceptable and/or that the function at hand would benefit greater from operating with or without arbitration, provide the monitor circuit118with a determination as to whether or not to employ arbitration. Then for example, the host processor may later change the determination (e.g., whether or not to implement arbitration) and the system100may respond accordingly.

In the example ofFIG. 1, if it is determined that sufficient isolation exists between the WLAN transceiver102and BT transceiver104, then so long as they have access to an available antenna (via the switches1108A and2108B), either transceiver (e.g.,102or104) may transmit and/or receive packets independent of the other without needing to account for the potential receiver desensitization of the other transceiver. Furthermore, the AFH logic116may prevent, avoid or otherwise minimize collisions between the packets being transmitted and/or received by the two transceivers. However, even in the case of sufficient isolation, arbitration of the use of antenna2106B may still be implemented during the times when BT transceiver104is not transacting BT packets (e.g., as indicated by the BT_ACTIVE signal112), so that the WLAN transceiver102may take advantage of the available antenna2106B and implement diversity with the WLAN packets received via both antennas, as discussed above.

If however, sufficient isolation is not achieved between the WLAN transceiver102and the BT transceiver104such that potential receiver desensitization may be an issue, then the coexistence interface120may arbitrate the transmission and/or receipt functions between the two transceivers. Insufficient isolation, as discussed above, may result in receiver desensitization. To prevent and/or minimize the likelihood of receiver desensitization, the coexistence interface120may arbitrate access to the antennas (106A and106B), such that a first transceiver may not transmit packets while a second transceiver is receiving packets, and/or vice versa. For example, the coexistence interface120may prevent the BT transceiver104from transmitting BT packets via antenna2106B while the WLAN transceiver102is receiving WLAN packets on antenna1106A, and/or vice versa. The arbitration may then prevent a transceiver from receiving the energy emitted by the other transceiver during transmission by for example assigning time slots to when either transceiver may transmit and/or receive packets.

With arbitration, during the time the WLAN transceiver102is receiving WLAN packets via antenna1106A, the BT transceiver104may be prevented from transmitting BT packets via antenna2106B. Then if the BT transceiver104has no BT packets to receive during that time, the WLAN transceiver102may be provided access to antenna2106B (e.g., the ACP110may toggle switch2108B), so that the WLAN transceiver102may receive packets via both antennas and perform diversity.

In another example embodiment, the coexistence interface120may prevent the WLAN transceiver102from transmitting packets while the BT transceiver104is receiving BT packets, or vice versa. Then for example, while BT transceiver104is receiving BT packets via antenna2106B, the WLAN transceiver102may receive WLAN packets via antenna1106A. An example of the coexistence interface120may include a 3-wire coexistence interface120, described in U.S. patent application Ser. No. 11/143,559, filed Jun. 2, 2005, titled “Method and system for achieving enhanced quality and higher throughput for collocated IEEE 802.11B/G and bluetooth devices in coexistent operation,” which is incorporated by reference herein for all purposes. Also, as discussed above, if the WLAN transmitter102is transmitting via antenna1106A and the BT transceiver104has nothing to transmit, then the WLAN transmitter102may transmit via both antennas using diversity.

If sufficient isolation is not achieved, the WLAN transceiver102and the BT transceiver104may both simultaneously transmit packets or may both simultaneously receive packets, without receiver desensitization occurring. This may be regulated for example by the coexistence interface120. According to an example embodiment, during the periods when both transceivers are transmitting, the BT transceiver104may employ the AFH logic116to further help avoid collisions/interference. As referenced above, the BT transceiver104(using AFH logic116) may determine a frequency band with the lowest background noise and transmit on that frequency, which may allow a BT receiver to receive a signal with a high signal-to-noise ratio.

While the example ofFIG. 1is shown such that only antenna2106B may be shared between the WLAN transceiver102and the BT transceiver104, it may be appreciated however that the example system ofFIG. 1, is only one of several example embodiments. For example, in other example embodiments (which may include additional switches), both antenna1106A and antenna2106B may be shared between the two transceivers (e.g.,102and104) whereby both transceivers may perform transmission and/or receipt functions (which may or may not be arbitrated between transmissions and receipt based on isolation and/or a function or type of packet being received, as discussed above). Then for example, if the BT transceiver104requests access to an antenna, the WLAN transceiver102and/or the ACP110may provide the BT transceiver104access to the antenna over which the WLAN transceiver102is receiving the weaker signal. Also other alternative embodiments may include additional transceivers, switches and/or antennas.

While the system100is adaptable to include more than just the two antennas shown (e.g., antenna1106A and antenna2106B) to be shared between the WLAN transceiver102and BT transceiver104(and even one or more other transceivers), only two antennas are included in the system100due to constraints that may arise during the implementation of system100in one or more devices. For example, the system100may be implemented in portable network electronics, such as a laptop. In such electronics it may be desirable to limit the number of antennas to two, not only for power consumption reasons (as more antennas may result in greater power consumption), but also for physical space limitations because in modern electronics, smaller devices with fewer components may be more desirable than larger devices.

As just referenced, the system100may allow for the WLAN and BT transceivers (e.g.,102and104respectively) to share two or more antennas, thus allowing the WLAN transceiver102to employ diversity during the receipt and/or transmission of packets via both antennas during those times the BT transceiver104may be idle and/or have a relatively low BT signal priority. The WLAN transceiver102may be able to determine the activity and/or priority based on a signal (e.g., BT_ACTIVE signal112), flag or interrupt provided, set or otherwise asserted by the BT transceiver104during those times when the BT transceiver104is requesting access or currently using a shared antenna. Through the use of a coexistence interface120, the system100may further be able to defend against potential receiver desensitization.

FIG. 2is a timing diagram200that illustrates an exemplary communication of the system100ofFIG. 1according to an example embodiment. WhileFIG. 2illustrates an example timing diagram200representing example operations related to the system100ofFIG. 1, it should be appreciated however that the timing diagram200is not limited to the example of system100and may be applied to other systems. It may also be appreciated that different systems, including the system100, may have other timing diagrams in addition to and/or in lieu of the timing diagram200. For example, other systems may employ different protocols in addition to and/or in lieu of the WLAN and Bluetooth (BT) protocols.

Referring toFIG. 2, the WLAN transceiver102may be configured to transmit and receive WLAN packets over antenna1106A and only receive WLAN packets via antenna2106B, whereby the BT transceiver104may be configured to transmit and receive BT packets only over antenna2106B. As discussed above, during the time period when the WLAN transceiver102is receiving WLAN packets over both antennas (e.g., antenna1106A and antenna2106B), the WLAN transceiver102may employ receipt diversity to improve the likelihood of the receipt of an accurate and/or stronger signal. Also, in the example diagram200, it may be appreciated that sufficient isolation exists such that receiver desensitization is not an issue is assumed, however in other example embodiments, such sufficient isolation may not exist.

In the example ofFIG. 2, time202may represent blocks of time, periods of time, durations and/or other timing measurements associated with tracking transactions (e.g., transmissions and receipts). For example, T0may represent the block of time (e.g., duration) required to receive a WLAN packet.

During time T0and T1, the WLAN transceiver102may have access to both antenna1106A and antenna2106B, thus may receive WLAN packets during the time T0-T1, and during this time period the WLAN transceiver102may perform diversity (e.g., DV), such as selection diversity, and receive the WLAN packet received via the stronger antenna.

During time T2, the BT transceiver104may assert the BT_ACTIVE signal112(or set a BT_ACTIVE flag, or interrupt) which may be received or otherwise detected by the WLAN transceiver102(and/or ACP110). Then for example, access to antenna2106B may be transferred from the WLAN transceiver102to the BT transceiver104. As discussed above, the BT_ACTIVE signal112may be associated with a guard time within which to complete and/or terminate the WLAN activity. The guard time, may include for example, a guard time of 0, in which case the ACP110and/or the WLAN transceiver102may immediately terminate whatever WLAN packet reception is being performed by the WLAN transceiver102and transfer access to the BT transceiver104.

During the time period T2, the WLAN transceiver102may receive a WLAN packet via antenna1106A and the BT transceiver104may begin to transmit a BT packet via antenna2106B. Because during the time period T2, the WLAN transceiver102is only receiving via a single antenna, the WLAN transceiver102may no longer perform diversity during the receipt of WLAN packets.

During the time T3-T4, both the WLAN transceiver102and the BT transceiver104may be transmitting packets, the WLAN transceiver102via antenna1106A and the BT transceiver104via antenna2106B, whereby the BT_ACTIVE signal112may still be active or asserted.

During the time T5, when the BT_ACTIVE signal112is no longer active, access to antenna2106B may be restored to the WLAN transceiver102which may begin receiving WLAN packets over both antennas and perform diversity.

During the time period T11, the BT transceiver104may be receive a BT packet, during which time the BT_ACTIVE signal112may remain active or in other example embodiments a new second BT_ACTIVE receipt signal may be provided by the BT transceiver104. Also, during the time period T11, the WLAN transceiver102may be transmitting a WLAN packet.

In those example embodiments where sufficient isolation is not achieved between the WLAN transceiver102and the BT transceiver104, it may be appreciated that during a given time202, for example T2, WLAN transceiver102may be prevented from receiving a WLAN packet via antenna1106A while BT transceiver104is transmitting a BT packet via antenna2106B, or vice versa.

Although not shown in the example system200, it may be understood that WLAN packet transactions may occur in pairs of transmission/receipt and/or receipt/transmission. For example, upon receipt of a WLAN packet via antenna1106A from a WLAN station, the WLAN transceiver102may transmit an acknowledgement (ACK) packet back to the station that transmitted the WLAN packet within a short interframe space (SIFS) between transmissions by the station. In BT transmissions it may be understood that a master-slave relationship may exist between the BT transceiver104and another BT device, in which case, the slave may only transmit to the master when addressed by the master, but the master may freely transmit to the slave. Also, it should be appreciated that the relative transmission and receipt durations of the BT and WLAN packets as shown inFIG. 2are exemplary only, and that packet transmission and/or receipt durations may vary.

FIG. 3is a flowchart300illustrating example operations of the system ofFIG. 1. More specifically,FIG. 3illustrates an operational flow300representing example operations related to a dual antenna topology. WhileFIG. 3illustrates an example operational flow300representing example operations related to the system100ofFIG. 1, it should be appreciated however that the operational flow300is not limited to the example of system100and may be applied to other systems.

After a start operation, at block310, it may be determined whether the Bluetooth (BT) transceiver is idle. For example, inFIG. 1, antenna control processor (ACP110) may determine whether the BT transceiver104is idle based on whether the BT_ACTIVE signal112is being transmitted or otherwise asserted by the BT transceiver104. If for example, the BT_ACTIVE signal112is being asserted by the BT transceiver104then that may indicate the BT transceiver104is not idle (e.g., transacting or ready to transact BT packets).

At block320, if the BT transceiver is not idle, it may be determined whether the BT transceiver104has access to a shared antenna. For example, ACP110may determine whether or not switch2108B is set such that antenna2106B is set to transact (e.g., transmit and/or receive) BT packets.

At block330, if the BT transceiver does not have access to the shared antenna, the WLAN packet receipt may be terminated within a guard time. For example, if the switch2108B is set to receive WLAN packets, then the WLAN transceiver102and/or ACP110may terminate the WLAN packet receipt within the guard time associated with the BT_ACTIVE signal112. In other example embodiments a WLAN packet transmission may be completed within the guard time.

At block340, the BT transceiver may be provided access to the shared antenna. For example, the ACP110may activate or otherwise toggle switch2108B such that antenna2106B is set to transmit/receive BT packets. According to an example embodiment, the termination of a WLAN packet receipt at block330and providing access to the shared antenna (e.g., antenna2106B) to the BT transceiver104may both be done within the guard time.

At block350, once it is determined that the BT transceiver has access to the shared antenna, a BT packet may be transmitted or received via the shared antenna. For example, BT transceiver104may transmit and/or receive a BT packet via antenna2106B, during which time the BT transceiver104may assert the BT_ACTIVE signal112.

If it is determined at block310that the BT transceiver104is idle, then, at block360, the WLAN transceiver may be provided access to the shared antenna. For example, the BT transceiver104may not be transacting BT packets (e.g., is at least temporarily inactive or idle as indicated by a deasserted BT_ACTIVE signal112), then the ACP110may activate switch2108B such that antenna2106B is set to receive WLAN packets for WLAN transceiver102.

At block370, a WLAN packet may be received via the shared antenna. For example, the WLAN transceiver102may receive a packet via antenna2106B. The WLAN transceiver102may also receive a WLAN packet via antenna1106A and perform diversity on the packets received via the two antennas. The diversity may include diversity as performed by the diversity logic114, including selection diversity where the stronger of two or more signals is selected for receipt. In other example embodiment, the WLAN transceiver102may perform diversity while transmitting one or more WLAN packets via antenna1106A and antenna2106B.

FIG. 4is a flowchart400illustrating example operations of the system ofFIG. 1. More specifically,FIG. 4illustrates an operational flow400representing example operations related to a dual antenna topology. WhileFIG. 4illustrates an example operational flow400representing example operations related to the system100ofFIG. 1, it should be appreciated however that the operational flow400is not limited to the example of system100and may be applied to other systems.

After a start operation, at block410, it may be determined whether the Bluetooth (BT) transceiver is idle. For example, inFIG. 1, antenna control processor (ACP110) and/or WLAN transceiver102may determine whether the BT_ACTIVE signal112is being asserted by the BT transceiver104, or whether a BT_ACTIVE flag has been set, to determine whether or not the BT transceiver104is idle whereby a receipt or other determination of an asserted BT_ACTIVE signal112may indicate that the BT transceiver104is not idle.

If the BT transceiver is not idle, then at block420the BT transceiver may be checked again until it is found to be idle. For example, if the BT transceiver104is not idle (e.g., the BT transceiver104is transacting and/or is ready to transact BT packets), then the BT transceiver104may transmit or receive a BT packet. Then for example, the ACP110and/or WLAN transceiver102may check again whether the BT_ACTIVE signal112is still being transmitted or otherwise asserted.

Upon a determination that the BT transceiver is idle, at block430, the WLAN transceiver may be provided access to a shared antenna. For example, the ACP110may activate switch2108B and provide the WLAN transceiver102access to receive WLAN packets via antenna2106B.

At block440, WLAN packets may be received via multiple antennas, including the shared antenna, wherein the WLAN transceiver is configured to perform receive diversity. For example, the WLAN transceiver102may receive WLAN packets via antenna1106A and antenna2106B whereby the WLAN transceiver102may be configured to employ diversity logic114to perform receive (e.g., selection and/or combination) diversity on received WLAN packets. In other example embodiments, the WLAN transceiver102may transmit WLAN packets via the multiple antennas, including the shared antenna using transmit diversity.

At block450, a Bluetooth (BT) interrupt may be received. For example, the WLAN transceiver102may receive or otherwise determine the BT_ACTIVE signal112associated with the BT transceiver104is being asserted, which may indicate that the BT transceiver104is ready to receive and/or transmit a BT packet. Then for example, the WLAN transceiver102may set an interrupt in response to determining an assertion of the BT_ACTIVE signal112.

At block460, a WLAN packet receipt may be terminated within a guard time. For example, upon determination of the BT_ACTIVE signal112, the WLAN transceiver102and/or ACP110may terminate a (current) WLAN packet receipt (or transmission) via antenna2106B within a guard time. The WLAN transceiver102may store the status of the WLAN packet receipt (or transmission) prior to or at termination, so that upon being provided access to antenna2106B again or upon establishing a WLAN connection via antenna1106A, the WLAN transceiver102may pick up the reception (or transmission) where it previously left off. As discussed above, the WLAN transaction may be terminated with an interrupt.

At block470, the shared antenna may be provided to the BT transceiver. For example, the ACP110may activate or otherwise toggle switch2108B whereby antenna2106B is set such that the BT transceiver104may transmit and/or receive BT packets via antenna2106B.

FIG. 5is a flowchart500illustrating example operations of the system ofFIG. 1. More specifically,FIG. 5illustrates an operational flow500representing example operations related to a dual antenna topology. WhileFIG. 5illustrates an example operational flow500representing example operations related to the system100ofFIG. 1, it should be appreciated however that the operational flow500is not limited to the example of system100and may be applied to other systems.

After a start operation, at block510, it may be determined whether to use arbitration between a WLAN and a BT transceiver. InFIG. 1, the monitor circuit118may determine and/or receive a determination from a host processor (not shown) as to whether or not to use arbitration between the transceivers. For example, an embodiment may have sufficient isolation to work with or without arbitration. Then for example, based on the function(s) the embodiment may be performing, a host processor and/or the monitor circuit118may determine whether or not to use arbitration.

In another implementation, whether or not to perform arbitration may be based on what function(s) the system100is performing. For example, as discussed above, BT voice packets may require real-time delivery and minimal, if any, error correction in which case arbitration may not be desired due to the potential for lost BT packets.

If is determined that arbitration is not to be used, then, at block520, it may be determined whether the BT transceiver is idle. For example, the WLAN transceiver102and/or the ACP110may determine whether the BT transceiver104is idle based on an assertion of the BT_ACTIVE signal112. For example, the BT transceiver104may assert the BT_ACTIVE signal112when the BT transceiver104is active (e.g., transacting and/or is ready to transact one or more BT packets).

If the BT transceiver is idle, then, at block530, access to a shared antenna may be provided to the WLAN transceiver. For example, the ACP110may activate or otherwise toggle switch2108B, such that the WLAN transceiver102may receive WLAN packets via the antenna2106B.

If however the BT transceiver is not idle, then, at block540, access to a shared antenna may be provided to the BT transceiver. For example, the ACP110may toggle switch2108B such that the BT transceiver104may transmit and/or receive BT packets via antenna2106B. If the BT transceiver104already has access to the shared antenna, then the BT transceiver104retains access.

If it is determined that arbitration is to be used, then at block550it may be determined whether the BT transceiver is idle. For example, similar to block520, the WLAN transceiver102and/or the ACP110may determine whether or not the BT transceiver104is idle (e.g., at least temporarily inactive) based at least in part on the BT_ACTIVE signal112.

If the BT transceiver is determined to be idle at block550, then at block530access to a shared antenna may be provided to the WLAN transceiver. For example, the ACP110may activate switch2108B, such that the WLAN transceiver102may receive WLAN packets via the antenna2106B, as discussed above.

If however, the BT transceiver is not idle, then at block560access to a shared antenna may be provided to the BT transceiver. For example, the ACP110may terminate a current WLAN packet reception via antenna2106B and activate or toggle switch2108B to set antenna2106B to transmit/receive BT packets, within a guard time.

At block570, transmissions and receipt functions may be arbitrated between the WLAN transceiver and BT transceiver. For example, the coexistence interface120may arbitrate transactions by the WLAN transceiver102and the BT transceiver104, such that one transceiver may not receive packets while the other is transmitting packets.

FIG. 6is a flowchart illustrating example operations of the system ofFIG. 1. More specifically,FIG. 6illustrates an operational flow600representing example operations related to a dual antenna topology. WhileFIG. 6illustrates an example operational flow600representing example operations related to the system100ofFIG. 1, it should be appreciated however that the operational flow600is not limited to the example of system100and may be applied to other systems.

After a start operation, at block610, one or more signals associated with a first transceiver may be received via a plurality of antennas, wherein the first transceiver is configured to use diversity associated with the receipt of the signals via two or more of the plurality of antennas. For example, the WLAN transceiver102may receive one or more WLAN signals via antenna1106A and antenna2106B, whereby the WLAN transceiver102may use diversity logic114to apply diversity to the received signals.

At block620, based on an activity of a second transceiver, it may be determined that the second transceiver requires access to one or more of the antennas shared between the first transceiver and the second transceiver. For example, the WLAN transceiver102may determine that the BT_ACTIVE signal112has been asserted by BT transceiver104, indicating activity or potential activity by the BT transceiver104.

At block630, access to one or more of the shared antennas may be transferred from the first transceiver to the second transceiver based on the determination. For example, the ACP110may toggle or activate switch2108B to provide access to antenna2to the Bluetooth transceiver104.

FIG. 7is a flowchart700illustrating example operations of the system ofFIG. 1. More specifically,FIG. 7illustrates an operational flow700representing example operations related to a dual antenna topology. WhileFIG. 7illustrates an example operational flow700representing example operations related to the system100ofFIG. 1, it should be appreciated however that the operational flow700is not limited to the example of system100and may be applied to other systems.

After a start operation, at block710, it may be determined that an antenna shared between a Bluetooth transceiver and a WLAN transceiver is available to the WLAN transceiver based on an activity signal associated with the Bluetooth transceiver. For example, the WLAN transceiver102may determine that the BT_ACTIVE signal112is not being asserted by the BT transceiver104, which may indicate that the shared antenna (e.g., antenna2106B is available).

At block720, access to the shared antenna may be provided to the WLAN transceiver based on the determination, wherein the WLAN transceiver is configured to use diversity in transacting WLAN signals via a plurality of antennas, including the shared antenna. For example, the ACP110may activate or toggle switch2108B such that the WLAN transceiver102may receive WLAN signals via antenna2106B and apply diversity to the received WLAN signals using the diversity logic114.

At block730, access to the shared antenna may be transferred from the WLAN transceiver to the Bluetooth transceiver based on the activity signal. For example, the WLAN transceiver102may determine that the BT_ACTIVE signal112has been asserted by the BT transceiver104, and the ACP may toggle the switch2108B such that the BT transceiver104has access to transmit and/or receive BT signals via antenna2106B.

FIG. 8is a block diagram of an example system800this is similar to the example system100, except that system800includes an additional switch, SWITCH3,808B, that allows the WLAN transceiver102to use either Antenna1106A or Antenna2106B to transmit signals to another device. Switch3808B can be a SPDT switch interposed between antenna2106B and switch2106B. When switch3808B is in a first position it can be operatively connected to a transmitter of WLAN transceiver102, such that the WLAN transceiver can utilized with either antenna1or antenna2to transmit signals. When switch3808B is in a second position, it then can be operatively coupled either to a receiver or WLAN transceiver102or to the Bluetooth transceiver104, depending on the position of Switch2108B. The antenna control processor110also is connected to the Switch3808B and can control the position of switch808B.

Because the addition of switch3808B allows the WLAN transceiver102to transmit signals with either antenna1106A or antenna2106B, the WLAN transceiver may utilize transmission diversity to select either antenna1or antenna2for transmission of WLAN signals when the BT transceiver104is inactive. For example, the WLAN transceiver106may send a test signal to a receiver using both antenna1106A and antenna2106B, and the receiver may evaluate the strength of the signals received from the two antennas. Then the receiver may send a message to the system800to inform the system which signal was stronger. Based on the message from the receiver the antenna control processor may selected the appropriate antenna with which to send signals to the receiver with the strongest signal strength.