Communication in dual protocol environments

The present invention relates to communication in an environment in which interference from a signal relating to one communication protocol interferes with the reception of a signal relating to another communication protocol.

An example of such an environment is when transceivers corresponding to two protocols occupying the 2.4 GHz ISM (Industrial Science and Medical) band are located close to each other or in the same device, for example. It is a portable communication device. As an example, the IEEE 802.11b / g wireless LAN signal transceiver can be located in close proximity to or within the same device as the Bluetooth signal transceiver. IEEE802.11b / g and Bluetooth share the 2.4GHz band, causing mutual interference between the two protocols. Due to this mutual interference, it is desirable to employ a coexistence method that enhances the ability of receivers corresponding to one protocol to operate in the presence of interference from signals from other protocols.

Existing coexistence methods, such as Bluetooth AFH (adaptive frequency hopping) and IEEE802.15.2PTA (packet traffic arbitration), have high duty for both IEEE 802.11 and Bluetooth when transceivers corresponding to each protocol are located close to each other. Inappropriate to support cycle operation. This is because an IEEE802.11b / g receiver cannot satisfactorily receive packets at the same time (even if it does not operate at the same frequency using AFH) when transmitting by a so-called Bluetooth transmitter located in close proximity. Because. Also, when the other IEEE 802.11 device attempts to transmit data, the IEEE 802.11 data is lost when it arrives at the time of transmission by the Bluetooth transmitter because there is no control. The resulting packet delivery failure triggers IEEE 802.11 backoff operation, resulting in very low throughput and high latency.

This behavior is especially problematic for latency-sensitive applications such as Voice over Internet Protocol (VoIP). An example of a particularly problematic situation is when a mobile voice handset acting as a relay device receives voice data from an IEEE 802.11 access point (AP) via VoIP and sends this voice data to the headset via a synchronous Bluetooth link. It's time to relay. This state is shown in Figure 1. The transmission and reception of voice packets by the handset's IEEE 802.11 and Bluetooth transceivers is essentially periodic (with some jitter). However, since there is no synchronization and the periodicity differs between the two radio links, packet collisions are unavoidable. Without an effective protection mechanism, almost all IEEE 802.11 packets from the access point to the handset are corrupted. Traffic is voice traffic, and large delays are not allowed, resulting in very poor quality voice transfer due to collisions.

<p> Therefore, there is a need for mechanisms to improve the coexistence of systems such as IEEE 802.11 and Bluetooth.</p>

<p> According to one aspect of the invention, there is a first communication system that transmits and / or receives signals according to a first program and a second communication system that transmits and / or receives signals according to a second protocol. In the second protocol, the receiver instructs the transmitter that he / she is in an unresponsive state, and the transmitter outputs data to the receiver when the receiver is in an unresponsive state. The second communication system having a function of prohibiting transmission, a signal activity detector for detecting the signal activity of the first protocol, and the second communication system in response to the signal timing detector. The communication system provides a communication device including a control unit that indicates that the own system is in an unresponsive state.</p><p> According to a second aspect of the invention, in a first communication system that transmits and / or receives signals according to a first program and in a second communication system that transmits and / or receives signals according to a second protocol. There, the second protocol tells the transmitter that it is in an unresponsive state, and the transmitter to the receiver when the receiver is in an unresponsive state. In a method of operating a communication device including a second communication system having a function of prohibiting data transmission, a step of detecting or predicting a cycle of signal activity of the first protocol, and the first step. When one protocol is detected or predicted to be active, the second communication system provides a method of operating the communication system including a step of instructing the own system to be in an unresponsive state.</p><p> In response to the signal activity detector, the control unit causes the second communication system to indicate that its own system is in an unresponsive state when the first protocol is detected to be active. It is preferable to configure it.</p><p> In response to the signal timing detector, the control unit is configured to indicate that its own system is in a responsive state by the second communication system when the first protocol is detected to be inactive. It is preferable to do so.</p><p> The communication device comprises a signal activity predictor that predicts the activity of the system of the first protocol in response to the signal activity detector, and the control unit comprises the signal timing detector via the signal activity prediction. In response to, when the first protocol is predicted to be active, it is preferable to configure the second communication system to indicate that the own system is in an unresponsive state.</p><p> The signal activity predictor is preferably configured to predict the activity of the signal of the first protocol by detecting the periodicity of the signal of the first protocol. Alternatively, the signal activity predictor may be configured to predict the activity of the signal of the first protocol by detecting the synchronization of the signal of the first protocol with the pre-stored activity schedule. it can.</p><p> The control unit is configured to respond to the signal timing predictor to indicate that the system is in a responsive state by itself when the first protocol is predicted to be inactive. You can also do it.</p><p> The first and second protocols can be different or the same. It is advantageous for the first and second protocols to occupy a common frequency band. The first protocol can be Bluetooth. The second protocol can be a wireless local area network protocol, such as the IEEE 802.11 protocol.</p><p> The above state can be a power save state.</p><p> One of the first and second protocols can be Bluetooth SCO or eSCO.</p><p> The first communication system and the second communication system are preferably arranged in a common housing.</p><p> The second communication system can be configured to relay the traffic data received by the first communication system according to the first protocol by transmitting it according to the second protocol.</p><p> The first communication system and the second communication system have an antenna, in which the signal of the first protocol transmitted by the antenna of the first communication system interferes with the signal of the second protocol. It may be arranged so as to prevent the signal of the second protocol from being successfully received by the first communication system.</p><p> The first communication system and the second communication system have a common antenna, and in both systems, the signal of the first protocol transmitted by the first communication system using the antenna is the signal of the second protocol. It may be configured to interfere with and prevent the successful reception of the signal of the second protocol by the first communication system.</p><p> The signal of the first protocol can be a signal transmitted according to the first protocol by another device far away from the radio transmitter.</p><p> The method can include terminating the transmission of traffic data by the second protocol to the communication device when the second communication system indicates that its system is in a non-responsive state.</p><p> The method can include a step of buffering traffic data for the communication system when instructing the second communication system to be unresponsive.</p><p> The method can include a step of instructing the own system to be in a responsive state by the second communication system when the first protocol is predicted to be inactive.</p><p> The method can include a step of transmitting traffic data to the communication device by the second protocol when instructing the second communication system to be in a responsive state.</p><p> The method can include a step of transmitting the buffered traffic data to the communication device by the second protocol when instructing the second communication system to be in a responsive state.</p><p> The present invention will be further described with reference to the accompanying drawings as an example.</p>

Like many other protocols, IEEE 802.11 includes a power save (PS) mechanism that reduces power consumption by turning off or disabling the radio when there is no data to transfer. Although not intended for their use within the IEEE 802.11 standard, in this system these mechanisms are destroyed to prevent the IEEE 802.11 device from sending data packets in order to improve coexistence with Bluetooth. ..

FIG. 2 schematically shows a system in which the present invention can be used.

The system includes transceivers 2 and 3 for signals conforming to the first radio protocol and transceivers 4 and 5 for signals conforming to the second radio protocol. Transceivers 3 and 4 are co-located within device 1. The first radio protocol is that the transmission timing of the signal by the transceiver 2 can be controlled by the transceiver 3 during operation. Preferably, transceiver 3 can signal transceiver 2 that it is in or is about to enter a data unreceivable mode, and the first protocol is that transceiver 2 is in this mode for such signaling. Expect to respond by not sending data to transceiver 3 while in. The second radio protocol causes the transmission of signals in bursts (eg, packets or frames). An example of such a situation is when the first wireless protocol is IEEE 802.11 and the second protocol is Bluetooth.

Transceiver 4 can know when activity (transceiver 4 transmit activity is most important) is expected on the link between Transceiver 4 and Transceiver 5. This is because, for example, activities occur in periodic time slots or are scheduled according to an algorithm. Transceiver 4 signals transceiver 3 the number of times such activity is expected. At this time, the transceiver 3 signals the transceiver 2 that it is in the data unreceivable mode during these times. As a result, Transceiver 2 prohibits the transmission of data during these times. Therefore, the risk of data loss caused by transceiver 3 having to receive when the link between transceivers 4 and 5 is active is reduced.

To give an example of device 1 with built-in both IEEE 802.11 (via Transceiver 3) and Bluetooth (via Transceiver 4) functionality, voice calls use IEEE 802.11 VoIP and Bluetooth SCO or eSCO from Transceiver 2 to Transceiver 5 Transferred to. Bluetooth used by device 1 The timing of the SCO slot is known to the Bluetooth transceiver 4 and can be signaled to the co-located IEEE 802.11 transceiver 3. Any suitable mechanism can be used for this signaling, but a preferred example is PTA (Packet Traffic Arbitrator). PTA is an independent entity that can receive status information from both Bluetooth and IEEE 802.11 wireless communications, send requests, and grant transmission permission to one or both of these wireless communications. The decision to grant permission is made by the PTA based on an assessment of the risk of collision. At this time, the co-arranged IEEE 802.11 transceiver 3 uses the PS signaling mechanism with the other IEEE 802.11 transceiver 2 to communicate with, and the transceiver is expected to be Bluetooth. Signals that it is in power save mode during the SCO slot and is active for the rest of the time. To other transceivers using the PW (Power Management) bit in the frame control field of the header of the packet sent from Transceiver 3 to Transceiver 2, the IEEE 802.11 radio communication receiver 3 is asleep in the SCO slot, but between them. It is possible to signal that it is an awake in the gap of. In this way, device 1 can force the remote IEEE 802.11 transceiver 2 to send data to the IEEE 802.11 transceiver 3 in the gap between SCO packets.

When the remote transceiver 2 is not forced to send data to transceiver 3, transceiver 2 buffers packets destined for transceiver 3 (eg, VoIP packets). This is part of the normal support that Transceiver 2 gives to PS mode. When transceiver 3 indicates that it is awake, a packet destined for device 1 is sent to transceiver 3. If the packet is for a delay-critical protocol such as VoIP, Transceiver 2 can decide not to send packets that are delayed more than a given amount to prevent excessive delays.

The performance of this technology can be improved using Bluetooth AFH (adaptive frequency hopping). If transceivers 3 and 4 are designed to avoid excessive mutual interference (eg, with proper isolation and / or shielding), the use of AFH is that both transceivers successfully receive at the same time and successfully at the same time. Allows you to send. This can be achieved by running Bluetooth with AFH on an IEEE 802.11 transceiver at frequencies that are not used at the same time. In this case, the uplink data packet from the mobile device to the IEEE 802.11 transceiver 2 can be buffer wrapped with the Bluetooth transmit slot, leaving a lot of time for the downlink packet.

When implemented using IEEE 802.11 and Bluetooth as described above, this technique does not require dedicated protocol conversion or advanced protocol features for any of transceivers 2-5. Compared to prior art, this technology can be fully implemented within device 1. Therefore, it can work with the existing fixed devices of transceivers 2 and 5.

Another advantage of the above method is that power saves on the links between transceivers 2 and 3 can be achieved when power saves are not used in the normal environment. Further, by imposing the time division operation on the device 1 as described above, it is possible to efficiently share a single antenna between IEEE 802.11 and Bluetooth.

In certain cases of IEEE802.11, other methods that can be used to synchronize the behavior of transceiver 2 with the expected activity of the link between transceivers 4 and 5 instead of changing the PM bit in the frame header. There is a power save signaling method. The following are options.

(i) PS-Poll frames can be used to solicit a single packet from Transceiver 2. This gives better performance when used with transceivers that support immediate PS-Poll responses, but if Transceiver 2 uses delayed PS-Poll responses, more IEEE 802.11 packets are forwarded each. It will be sent for the data packet. Another drawback is that the behavior is not well defined if the packets are not buffered.

(ii) If both Transceiver 2 and Transceiver 3 support IEEE 802.11e UAPSD (Unscheduled Automatic Power-Save Delivery), use uplink data to trigger Transceiver 2 to send buffered downlink data packets. Can be made to. This is more efficient than changing the PM bits or using PS-Poll packets, but you have to rely on the optional features provided by Transceiver 2.

The same mechanism can also be used to support coexistence with any other co-located communication (non-Bluetooth) that is exacerbated or causes such interference by interference with IEEE 802.11.

A mechanism capable of performing signaling between transceivers 3 and 4 will be described with reference to FIG. Each of the transceivers 3 and 4 comprises protocol processing units 6 and 8 that encode and decrypt traffic data according to the protocol used by each, and control units 7 and 9 that control the operation of each transceiver. The control unit 9 of the transceiver 4 knows or can predict when the link between the transceiver and the transceiver 5 is active. The control unit 9 sends this information to the control unit 7 of the transceiver 3, so that the control unit 7 sends a signal to the protocol processing unit 6 of the transceiver 3 indicating that the transceiver 3 enters or exits the power save mode. Signal.

FIG. 3 shows the signaling timing for an embodiment in which device 5 is a Bluetooth audio device and transceiver 2 is an IEEE 802.11 access point. The top column shows the activity of the link between transceivers 4 and 5. There is a 2.5ms periodic window where HV3 frames are sent but there is no Bluetooth activity. The second and third columns show transmissions on the link between transceivers 2 and 3. At the start of the 2.5ms window, Transceiver 3 sends a signal (PM bit = 0) to Transceiver 2 indicating that it is out of the power save state. This is confirmed by transceiver 2, which sends traffic data (eg, VoIP data) to the transceiver. The traffic data is acknowledged and replied by the transceiver 3. Next, before the window closes, transceiver 3 signals transceiver 2 to enter the power save state (PM bit = 1). This is acknowledged by Transceiver 2, which stops transmitting data to Transceiver 3. Transceiver 2 can continue to send data to other receivers while Transceiver 3 is in the power save state. However, during this time, the data destined for Transceiver 3 must not be decoded, so this data is not destroyed by the signal on the link between Transceivers 4 and 5.

This method can also be used for protocols other than IEEE 802.11 and Bluetooth. The present invention can be conveniently used for any two communication technologies that are affected by mutual interference when operating simultaneously, allowing remote control of transmitter activity in one system to stop and start transmission. Is. The present invention can also be used for a single communication technology capable of maintaining multiple active communication links but only operating one at a time, eg, a Bluetooth device operating within a scatternet. ..

One of several protocols (protocol between transceivers 4 and 5 in Figure 2) The mechanism for predicting activity depends on the nature of communication according to the protocol. Some possible mechanisms are:

1. If communication according to the protocol is strictly or nearly periodic, this periodicity can be used to predict when the idle period will occur. The cycle can be preprogrammed by receiving successive signaling events or in units for predicting activity in the system.

2. If communication according to the protocol occurs according to a predetermined complex or aperiodic schedule, this schedule can be used to predict when the idle cycle will occur. The schedule can be set according to the nature of the protocol in use, and the schedule should be selected by transceivers 4 and / or 5 so that the idle period can be used for communication on the link between transceivers 2 and 3. Can be done. Schedules can be pre-programmed into units for predicting activity in the system. Communication can be detected in synchronization with the schedule stored in advance. This method can also be used for periodic transmissions. The schedule can also be incorporated as data that determines the relative timing of a series of transmissions.

3. Instead of predicting activity according to a periodic or aperiodic schedule, communications according to the protocol can also be easily predicted based on the presence of current activity on the link. Activity on the link between transceivers (2 and 3) can be stopped or prohibited in response to detection of current activity on the link between transceivers 4 and 5.

Mechanisms 1 and 2 described above detect the timing of one or more instances of activity on the link between transceivers 4 and 5 and feed them into the prediction algorithm. This algorithm attempts to detect the periodicity of the activity, or applies one or more pre-stored activity patterns to the detected activity. Once a pattern has been determined and synchronized with the detected activity, the algorithm outputs an indication of when future activity is expected. On the contrary, Algorithm 3 does not predict future activity by the algorithm, but simply responds to the current activity.

Activity on the link between transceivers 2 and 3 is controlled in response to activity on the link between transceivers 4 and 5 or in response to transmission of activity by transceiver 4 co-located with transceiver 3. be able to.

The mechanism that controls activity on the link between transceivers 2 and 3 depends on the protocol used for that link. A mechanism in which the transmitter (transceiver 2) is controlled by the communication partner (transceiver 3) to start or stop the transmission of data (at least traffic data) to the communication partner is preferable. This mechanism is preferably implemented by a message sent over the link indicating the start or stop of such communication. The transmitter (transceiver 2) is preferably configured to respond to these messages and to start and stop transmitting data (at least traffic data) to the other party according to these messages. In this state, there is an expected delay between the transmission of the "stop" message and the end of transmission by the transmitter (especially if the transmitter acknowledges the "stop" message), so the communication partner (transceiver 3) , Preferably configured to send a "stop" message on other links at least a predetermined time before the expected time of activity.

When the mechanism is in power save mode, the transceiver 3 can remain fully operational even when the mechanism is instructed to be in power save mode.

The device 1 can be configured to automatically relay the data sent via one of the links via the other links of the link.

Transceivers 3 and 4 located within device 1 can have separate antennas or can share the same antenna. These transceivers can also share other components such as receive and / or transmit power amplifiers and filters. These transceivers are preferably placed in the same housing, the housing of device 1. Device 1 can be a portable device such as a laptop converter, mobile phone or PDA. The device 1 can also be fixed in position. In one application, the repeater relays voice communication between a wireless LAN access point (with transceiver 2) and a user interface (with transceiver 5) such as a headset. Backhauling of signals from a wireless access point to a remote terminal can be done via a wired link from the access point (eg, an Ethernet® link).

Applicants claim the individual features disclosed herein or any combination of two or more of these features, regardless of whether such individual features or combinations thereof solve the problems disclosed herein. It is disclosed to the extent that it can be easily carried out by those skilled in the art based on the description of the present specification without limiting the scope described in the section. The applicant discloses that the features of the present invention may consist of any of these individual features or a combination thereof. From the above description, it is clear that those skilled in the art can make various modifications within the scope of the present invention.

<figref num="1">It is a figure which shows the system which relays audio data to a headset via a relay device.</figref><figref num="2">It is a figure which shows the wireless transceiver which can use this invention.</figref><figref num="3">It is a figure which shows the signal timing.</figref>