Abstract:
A technique is disclosed that enables both an IEEE 802.11 transceiver and a Bluetooth transceiver to be employed in a single wireless telecommunication station (e.g., a device supporting a wireless telephone, personal digital assistant, etc.) without interfering on each other. In particular, the illustrative embodiment enables standard “off-the-shelf” IEEE 802.11 and Bluetooth transceivers to work in a coordinated fashion in a single telecommunications terminal. In the illustrative embodiment, a Bluetooth transceiver gains access to a shared-communications channel from an IEEE 802.11 transceiver by requesting access, even if the access is not immediate. The technique disclosed is also applicable to communications protocols other than IEEE 802.11 and Bluetooth.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of:
     1. U.S. provisional application Ser. No. 60/452,309, filed 5 Mar. 2003, entitled “Blue802 Polite Request”
 
which is also incorporated by reference.
   

     The following patent applications are incorporated by reference:
     1. U.S. patent application Ser. No. 10/444,383, entitled “Multi-Protocol Interchip Interface”   2. U.S. patent application Ser. No. 10/444,519, entitled “Coordination of Competing Protocols,” and   3. U.S. patent application Ser. No. 10/680,877, entitled “Coordinating Multiple Air-Interface Subsystems that Serve a Common Host”   

    
    
     FIELD OF THE INVENTION 
     The present invention relates to telecommunications in general, and, more particularly, to wireless local area networks. 
     BACKGROUND OF THE INVENTION 
       FIG. 1  depicts a schematic diagram of local area network  100  in the prior art, which comprises telecommunication stations  101 - 1  through  101 -K, wherein K is a positive integer, and shared-communications channel  102 , interconnected as shown. Stations  101 - 1  through  101 -K enable associated host computers to communicate blocks of data, or “frames,” to each other. Stations  101 - 1  through  101 -K comprise transceivers that enable communications via shared-communications channel  102 . 
     In a mixed network such as local area network  100 , some of the stations (e.g., station  101 - 1 , etc.) operate in accordance with the IEEE 802.11 set of protocols, and some of the stations (e.g., station  101 - 4 , etc.) operate in accordance with the Bluetooth set of protocols. Still other stations of local area network  100  operate in accordance with both protocols. The stations comprising transceivers that communicate in accordance with IEEE 802.11 are able to take turns accessing shared-communications channel  102  because they all embody IEEE 802.11 access rules and follow those rules. Similarly, the stations comprising transceivers that communicate in accordance with Bluetooth are able to take turns accessing shared-communications channel  102  because they all embody Bluetooth access rules and follow those rules. 
     When IEEE 802.11 transceivers and Bluetooth transceivers—situated either in separate stations or within the same station—have to use the same, shared-communications channel (i.e., shared-communications channel  102 ), the rules for accessing (and sharing) shared-communications channel  102  are not as well defined as for the case where all transceivers use the same protocol. For example, Bluetooth station  101 - 4  might attempt to transmit when IEEE 802.11 station  101 - 1  is already transmitting, and the result would most likely be that neither station successfully transmits during that particular attempt. Depending on the contention for shared-communications channel  102 , neither the Bluetooth stations nor the IEEE 802.11 stations would operate effectively enough to be of much value to the end user. 
     Therefore, the need exists for a way to coordinate multiple air interface protocols that are used to access the same, shared-communications channel without some of the disadvantages in the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention enables both an IEEE 802.11 transceiver and a Bluetooth transceiver to be employed in a single telecommunication station without the transceivers interfering on each other. In particular, the illustrative embodiment enables standard, “off-the-shelf,” IEEE 802.11 and Bluetooth transceivers to work in a coordinated fashion in a single telecommunications station. In some embodiments, the two transceivers are in separate stations. 
     In the illustrative embodiment, a Bluetooth transceiver notifies an IEEE 802.11 transceiver that is using a shared-communications channel that the Bluetooth transceiver needs to use the shared-communications channel, though not necessarily immediately. The channel access control mechanism associated with the IEEE 802.11 transceiver determines when to relinquish control of the shared-communications channel to the Bluetooth transceiver and then grants the Bluetooth transceiver&#39;s request to use the shared-communications channel. The IEEE 802.11 transceiver can choose to (i) power down or (ii) stay powered up when it relinquishes control of the shared-communications channel. 
     In some embodiments, the Bluetooth transceiver notifies the IEEE 802.11 transceiver when the Bluetooth transceiver finishes using the shared-communications channel. In other embodiments, the Bluetooth transceiver notifies the IEEE 802.11 transceiver in advance when the Bluetooth transceiver begins to finish using the shared-communications channel. The Bluetooth transceiver in those other embodiments then continues to use the shared-communications channel during the recovery period when the IEEE 802.11 transceiver transitions from a powered down to a powered up condition. 
     In this specification, the illustrative embodiment is disclosed in the context of the IEEE 802.11 and Bluetooth protocols. It will be clear to those skilled in the art, however, how to make and use alternative embodiments of the present invention for other combinations of competing protocols (i.e., protocols that might interfere with each other). In addition, although the illustrative embodiment is disclosed in the context of radio transceivers, it will be clear to those skilled in the art how to make and use alternative embodiments of the present invention for non-radio frequency wireless devices or wireline transceivers that might interfere with each other. 
     The illustrative embodiment of the present invention comprises: asserting a polite request signal that requests that a first transceiver relinquish transmitting via a shared-communications channel, wherein the first transceiver communicates in accordance with a first communications protocol; indicating via the shared-communications channel that a second transceiver hold subsequent transmissions to the first transceiver; asserting a first signal from the first transceiver that indicates that the first transceiver has relinquished transmitting via the shared-communications channel; and transmitting at least one frame from a third transceiver via the shared-communications channel after the asserting of the first signal, wherein the third transceiver communicates in accordance with a second communications protocol. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a schematic diagram of wireless local area network  100  in the prior art. 
         FIG. 2  depicts a schematic diagram of a portion of local area network  200  in accordance with the illustrative embodiment of the present invention. 
         FIG. 3  depicts a block diagram of the salient components of dual station  204 - 1  in accordance with the illustrative embodiment of the present invention. 
         FIG. 4  depicts a block diagram of the salient components of air interface subsystem  301 -i in accordance with the illustrative embodiment of the present invention. 
         FIG. 5  depicts a timing diagram of signals exchanged between air interface subsystems  301 - 1  and  301 - 2 , in accordance with the first illustrative embodiment of the present invention. 
         FIG. 6  depicts a timing diagram of signals exchanged between air interface subsystems  301 - 1  and  301 - 2 , in accordance with the second illustrative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  depicts a schematic diagram of a portion of local area network  200  in accordance with the illustrative embodiment of the present invention. Network  200  operates in accordance with the IEEE 802.11 and Bluetooth sets of protocols, and comprises access point  201 , first protocol 802.11 stations  202 - 1  through  202 -L, wherein L is a natural number; second protocol stations  203 - 1  through  203 -M, wherein M is a natural number; dual protocol stations  204 - 1  through  204 -N, wherein N is a natural number; host computers  205 - 1  through  205 -P, wherein P is equal to the sum of L, M, and N; and wireless shared-communications channel  206 , interconnected as shown. 
       FIG. 2  depicts a network configuration with L equal to two, M equal to two, and N equal to one. It will be clear, however, to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that use different values for L, M, and N. 
     In the examples provided in this specification, first protocol stations  202 - 1  through  202 -L and second protocol stations  203 - 1  through  203 -M are IEEE 802.11 and Bluetooth compliant, respectively. Furthermore, dual stations  204 - 1  through  204 -N are both IEEE 802.11 and Bluetooth compliant. Access point  201 , a coordinating station that is described below, is at least IEEE 802.11 compliant. In some embodiments, access point  201  is both IEEE 802.11 and Bluetooth compliant. It will be clear, however, to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that operate in accordance with other protocols. Furthermore, it will be clear to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that use a wireline or tangible shared-communications channel. 
     Access point  201  coordinates the communications of at least some of the stations within local area network  200 . For example, first protocol stations  202 - 1  through  202 -L and dual protocol stations  204 - 1  through  204 -N, when using the protocol of first protocol stations  202 - 1  through  202 -L, communicate with each other through access point  201 . It will be clear to those skilled in the art how to make and use access point  201 . 
     Each station comprises one or more transceivers that enable host computer  205 -j, for j=1 to P, to transmit signals and receive signals via shared-communications channel  206 . A “transceiver” is capable of two-way communication over a communications channel (e.g., shared-communications channel  206 , etc.). For example, dual station  204 - 1  is capable of receiving data blocks from host computer  205 - 5  (i.e., the host computer with which dual station  204 - 1  is associated) and transmitting over shared-communications channel  206  data frames comprising the data received from host computer  205 - 5 . Dual station  204 - 1  is also capable of receiving data frames from shared communications channel  206  and sending to host computer  205 - 5  data blocks comprising data from the data frames. It will be clear to those skilled in the art, after reading this specification, how to make and use dual station  204 - 1 . The salient details for dual station  204 - 1  are described below and with respect to  FIG. 3 . 
     Host computer  205 -j, for j=1 to P, is capable of generating data blocks and transmitting those data blocks to its associated station. Host computer  205 -j is also capable of receiving data blocks from its associated station and of processing and using the data contained within those data blocks. Host computer  205 -j can be, for example, a desktop computer, a laptop computer, a wireless telephone, or a personal digital assistant (PDA) that uses local area network  200  to communicate with other hosts and devices. It will be clear to those skilled in the art how to make and use host computer  205 -j. 
       FIG. 3  depicts a block diagram of the salient components of dual station  204 - 1  in accordance with the illustrative embodiment of the present invention. Dual station  204 - 1  supports two distinct wireless air interface protocols for the purpose of transmitting and receiving data over the air via shared-communications channel  206 . The wireless protocols supported by dual station  204 - 1  can be, for example, IEEE 802.11 and Bluetooth. Dual station  204 - 1  comprises: air interface subsystem  301 - 1 , air interface subsystem  301 - 2 , and antenna switch  302 , interconnected as shown; Air interface subsystem  301 - 1  and air interface subsystem  301 - 2  communicate with each other via interface  303 . 
     Air interface subsystem  301 -i, for i=1 to Q wherein Q is a positive integer greater than one, enables associated host computer  205 -j (i.e., host computer  205 - 5  paired with dual station  204 - 1 ) to communicate via shared-communications channel  206 . In the illustrative example, Q is equal to two. It will be clear, however, to those skilled in the art, after reading this specification, how to make and use dual station  204 -i with other values of Q. 
     Air interface subsystems  301 - 1  and  301 - 2  comprise the transceivers that enable host computer  205 -j to communicate using two different air interface protocols. Each of air interface subsystems  301 - 1  and  301 - 2  operates in accordance with a different air interface protocol (e.g., IEEE 802.11, Bluetooth, etc.). It will be clear to those skilled in the art, after reading this specification, how to make and use air interface subsystems  302 - 1  and  302 - 2 . 
     Antenna switch  302  enables air interface subsystems  301 - 1  and  301 - 2  to share a single antenna unit for the purpose of using shared-communications channel  206 . Antenna switch  302  provides signals to air interface subsystem  301 -i. Antenna switch  302  also accepts signals from air interface subsystem  301 -i. It will be clear to those skilled in the art how to make and use antenna switch  302 . 
       FIG. 4  depicts a block diagram of the salient components of air interface subsystem  301 -i in accordance with the illustrative embodiment of the present invention. Air interface subsystem  301 -i comprises receiver  401 -i, processor  402 -i, memory  403 -i, and transmitter  404 -i, interconnected as shown. 
     Receiver  401 -i is a circuit that is capable of receiving frames from shared-communications channel  206 , in well-known fashion, and of forwarding them to processor  402 -i. It will be clear to those skilled in the art, after reading this specification, how to make and use receiver  401 -i. 
     Processor  402 -i is a general-purpose processor that is capable of performing the tasks described below and with respect to  FIGS. 5 through 9 . Processor  402 -i controls access to shared-communications channel  206  for air interface subsystem  301 -i in accordance with the applicable air interface protocol. It will be clear to those skilled in the art, after reading this specification, how to make and use processor  402 -i. 
     Memory  403 -i is capable of storing programs and data used by processor  402 -i. It will be clear to those skilled in the art how to make and use memory  403 -i. 
     Transmitter  404 -i is a circuit that is capable of receiving frames from processor  402 -i, in well-known fashion, and of transmitting them on shared-communications channel  206 . It will be clear to those skilled in the art, after reading this specification, how to make and use transmitter  404 -i. 
     The combination of receiver  401 -i and transmitter  404 -i constitutes the transceiver part of air interface subsystem  301 -i. 
       FIG. 5  depicts a timing diagram of signals exchanged between air interface subsystem  301 - 1  and  301 - 2 , in accordance with the first illustrative embodiment of the present invention. In accordance with the first illustrative embodiment of the present invention,  FIG. 5  depicts air interface subsystem  301 - 2  requesting that air interface subsystem  301 - 1  relinquish control of shared-communications channel  206 , though not necessarily immediately. In this specification, this action is referred to as a “polite request.” The polite request signal, when not asserted, also indicates when air interface subsystem  301 - 2  is not transmitting into shared-communications channel  206 . Although air interface subsystems  301 - 1  and  301 - 2  of dual station  204 - 1  are used as examples, it will be clear to those skilled in the art how to apply the tasks represented in  FIG. 5  of the illustrative embodiment to other air interface subsystems. 
     In some embodiments, signals are conveyed as discrete signal levels, and in other embodiments, signals are conveyed as packets.  FIG. 5  depicts signals occurring in both forms. It will be clear to those skilled in the art, after reading this specification, how to represent in actual implementation the signals depicted in  FIG. 5 . 
     At time  501 , air interface subsystem  301 - 2  asserts a polite request signal, which is subsequently detected by air interface subsystem  301 - 1 . Asserting the polite request signal-indicates that air interface subsystem  301 - 2  needs to use shared-communications channel  206 , though not necessarily immediately. 
     Air interface subsystem  301 - 1  detects the polite request signal being asserted by air interface subsystem  301 - 2 . Air interface subsystem  301 - 1  can relinquish control of shared-communications channel  206  immediately, or it can defer relinquishing control. It will be clear to those skilled in the art how to determine when air interface subsystem  301 - 1  relinquishes control of shared-communications channel  206 . 
     At time  502  when it is ready to relinquish control of shared-communications channel  206 , air interface subsystem  301 - 1  indicates to access point  201  to hold data frames arriving from other sources and that are addressed to air interface subsystem  301 - 1 . For example, the indication can be in the form of a message bit set to a value indicating that the transceiver of air interface subsystem  301 - 1  is entering a power save state in which air interface subsystem  301 - 1  powers down the transceiver. Air interface subsystem  301 - 1  can direct the action of powering down at the transmitter part, the receiver part, or both parts of the transceiver. In some embodiments, air interface subsystem  301 - 1  keeps its transceiver powered up, even though it informed access point  201  otherwise. 
     At time  503 , air interface subsystem  301 - 1  receives an acknowledgement that access point  201  received the indication. 
     At time  504 , air interface subsystem  301 - 1  sends a request granted signal to air interface subsystem  301 - 2  to indicate that air interface subsystem  301 - 1  yields shared-communications channel  206  and that air interface subsystem  301 - 2  can use shared-communications channel  206 . 
     At time  505 , air interface subsystem  301 - 2  begins using shared-communications channel  206  for transmitting, receiving, or both. 
     At time  506 , air interface subsystem  301 - 2  determines that it is near the end of operation on shared-communications channel  206  and un-asserts the polite request signal. In some embodiments, air interface subsystem  301 - 1  as a result begins a recovery interval, which is a transition period that the transceiver goes through while powering up. 
     At time  507 , air interface subsystem  301 - 1  informs access point  201  that air interface subsystem  301 - 1  has exited the power save state. For example, the PS-Poll frame is used in IEEE 802.11 for this purpose. 
     At time  508 , air interface subsystem  301 - 1  receives an acknowledgement from access point  201 . Air interface subsystem  301 - 1  proceeds to receive the data frames that have been held by access point  201  since time  502 . 
       FIG. 6  depicts a timing diagram of signals exchanged between air interface subsystem  301 - 1  and  301 - 2 , in accordance with the second illustrative embodiment of the present invention. In accordance with the second illustrative embodiment of the present invention,  FIG. 6  depicts air interface subsystem  301 - 2  requesting that air interface subsystem  301 - 1  relinquish control of shared-communications channel  206 , though not necessarily immediately. When it relinquishes control, air interface subsystem  301 - 1  enters and exits a power save state as described below. In the second illustrative embodiment of the present invention, air interface subsystem  301 - 2  uses separate polite request and transmit indications, which enable air interface subsystem  301 - 2  to continue transmitting while air interface subsystem  301 - 1  is exiting and recovering from the power save state. Although air interface subsystems  301 - 1  and  301 - 2  of dual station  204 - 1  are used as examples, it will be clear to those skilled in the art how to apply the tasks represented in  FIG. 6  of the illustrative embodiment to other air interface subsystems. 
     In some embodiments, signals are conveyed as discrete signal levels, and in other embodiments, signals are conveyed as packets.  FIG. 6  depicts signals occurring in both forms. It will be clear to those skilled in the art, after reading this specification, how to represent in actual implementation the signals depicted in  FIG. 6 . 
     At time  601 , air interface subsystem  301 - 2  asserts a polite request signal, which is subsequently detected by air interface subsystem  301 - 1 . Asserting the polite request signal indicates that air interface subsystem  301 - 2  needs to use shared-communications channel  206 , though not necessarily immediately. 
     Air interface subsystem  301 - 1  detects the polite request signal being asserted by air interface subsystem  301 - 2 . Air interface subsystem  301 - 1  can relinquish control of shared-communications channel  206  immediately, or it can defer relinquishing control. It will be clear to those skilled in the art how to determine when air interface subsystem  301 - 1  relinquishes control of shared-communications channel  206 . 
     At time  602  when it is ready to relinquish control of shared-communications channel  206 , air interface subsystem  301 - 1  indicates to access point  201  to hold data frames arriving from other sources and that are addressed to air interface subsystem  301 - 1 . For example, the indication can be in the form of a message bit set to a value indicating that the transceiver of air interface subsystem  301 - 1  is entering the power save state in which air interface subsystem  301 - 1  powers down the transceiver. 
     At time  603 , air interface subsystem  301 - 1  receives an acknowledgement that access point  201  received the indication. 
     At time  604 , air interface subsystem  301 - 1  enters the power save state. Air interface subsystem  301 - 1  can direct the action of powering down at the transmitter part, the receiver part, or both parts of the transceiver. In some embodiments, air interface subsystem  301 - 1  keeps its transceiver powered up, even though it informed access point  201  otherwise. 
     At time  605 , air interface subsystem  301 - 1  sends a request granted signal to air interface subsystem  301 - 2  to indicate that air interface subsystem  301 - 1  yields shared-communications channel  206  and that air interface subsystem  301 - 2  can use shared-communications channel  206 . 
     At time  606 , air interface subsystem  301 - 2  asserts the transmit indication signal. 
     At time  607 , air interface subsystem  301 - 2  begins using shared-communications channel  206  for transmitting, receiving, or both. 
     At time  608 , air interface subsystem  301 - 2  determines that it is near the end of operation on shared-communications channel  206  and un-asserts the polite request signal. In some embodiments, air interface subsystem  301 - 1  begins a recovery interval, which is a transition period that the transceiver goes through while powering up. Air interface subsystem  301 - 2  continues transmitting into shared-communications channel  206 . 
     At time  609 , air interface subsystem  301 - 2  ceases using shared-communications channel  206  and un-asserts the transmit indication signal. 
     At time  610 , air interface subsystem  301 - 1  completes the powering-up recovery and exits the power save state in those embodiments in which it had entered the power save state. Air interface subsystem  301 - 1  detects the un-asserting of the transmit indication signal of air interface subsystem  301 - 2  and resumes using shared-communications channel  206  as needed. 
     At time  611 , air interface subsystem  301 - 1  informs access point  201  that air interface subsystem  301 - 1  has exited the power save state. For example, the PS-Poll frame is used in IEEE 802.11 for this purpose. 
     At time  612 , air interface subsystem  301 - 1  receives an acknowledgement from access point  201 . Air interface subsystem  301 - 1  proceeds to receive the data frames that have been held by access point  201  since time  602 . 
     It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.