Mitigation of internetwork interference

A small wireless network that has multiple interrelated devices, one of which acts as a piconet network controller (PNC) and schedules most of the communication within the network, is often referred to as a piconet. In a high-density network environment where a large number of piconets are formed in a relatively small area, the physical ranges of adjacent piconets may overlap, causing interference between devices of different piconets. A typical PNC establishes a time slot to communicate during each superframe for each device in the network. The device may continue to communicate in the same time slot in multiple (sometimes many) superframes. Therefore, if interference occurs between networks, the interference may be repeated at each superframe for a long period of time. However, once interference occurs, it is easy to assume this, but it can be difficult to adjust the schedule of different piconets to mitigate the interference. In traditional systems, (1) if multiple PNCs can communicate directly, that is, they are aware of each other's schedule, at least one PNC schedules its own network idle period while the other network is active. By doing so, the occurrence of interference between networks can be prevented, or (2) if multiple PNCs cannot communicate directly, the method (1) should be performed after reassigning the PNC function to devices that are close to being able to communicate directly with each other. I had no choice but to use it. These techniques are not always effective or feasible. Scheduling the network idle period significantly reduces the overall network bandwidth. Reassigning PNC functionality is a fairly complex and time-consuming process. In addition, reassigning PNC functionality to one side of a piconet may cause it to fall outside the PNC range of another adjacent piconet and simply move to another piconet without resolving the issue.

Some embodiments of the present invention may be understood by reference to the following detailed description and accompanying drawings used to illustrate embodiments of the present invention. The drawing is as follows.

<figref num="1">A network diagram of two overlapping networks with interference between the networks is shown.</figref><figref num="2">FIG. 3 shows a network diagram attempting to mitigate the interference of FIG. 1 according to an embodiment of the present invention.</figref><figref num="3">A flow diagram of a method related to the network diagram of FIG. 2 according to an embodiment of the present invention is shown.</figref><figref num="4">FIG. 2 shows another network diagram that attempts to mitigate the interference of FIG. 1 according to an embodiment different from the embodiment of the present invention shown in FIG.</figref><figref num="5">A flow diagram of a method related to the network diagram of FIG. 4 according to an embodiment of the present invention is shown.</figref>

In the following description, various specific details will be shown. However, it should be understood that embodiments of the present invention can be implemented without the use of these specific details. In other cases, well-known circuits, structures and techniques will not be detailed in order to avoid obscuring the understanding of the description.

"One embodiment," "an embodiment," "exemplary embodiment," "various embodiments," etc., wherein one or more embodiments of the invention described have a particular function, structure, or. Indicates that the property may be included, but not necessarily all embodiments include a particular function, structure or property. Further, some embodiments may include some or all of the functions described in another embodiment, or may not include them at all.

In the following description and claims, "combined", "connected" and similar terms may be used. It should be understood that these terms are not intended to be synonymous with each other. To be precise, "connected" in a particular embodiment is used to indicate that two or more elements are in direct physical or electrical contact with each other. "Combined" is used to indicate that two or more elements interact or interact with each other, which may or may not be in direct physical or electrical contact.

Unless otherwise specified, the use of ordinal numbers such as "first," "second," and "third" to indicate common elements is simply different, as used in the claims. It is intended only to indicate that similar elements are referenced in, and to imply that the described elements must be in a particular order in time, space, ordinal or in any way. Absent.

Various embodiments of the invention can be implemented in one or any combination of hardware, firmware and software. The present invention can also be implemented as an instruction executed by one or more processors and contained in or on a machine-readable medium that enables the execution of the operations described herein. A machine-readable medium may include any mechanism for storing, transmitting and / or receiving information in a machine-readable format such as a computer. For example, the machine-readable medium is not limited to these, and may include a tangible storage medium such as a ROM, RAM, a magnetic disk storage medium, an optical storage medium, and a flash memory device. The machine-readable medium may also include, but is not limited to, a propagating signal modulated to encode a command such as an electromagnetic signal, an optical signal or a voice carrier signal.

The term "radio" and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communication channels, etc. that communicate data over non-solid media by using modulated electromagnetic radiation. .. The term does not mean that the associated device is wireless, but in some embodiments it may be. The term "mobile" wireless device is used to describe a wireless device that is mobile during communication.

The description in this document generally describes a wireless communication network known as a piconet. However, the intent and technology described may be used in other types of networks. Unless otherwise specified, various embodiments of the present invention are not limited to piconets.

Various embodiments of the invention use non-controller network devices to detect interference between two overlapping networks. Scheduling information is then communicated between the networks and scheduling is adopted on at least one network to avoid interference. In one embodiment, the device that detects the interference broadcasts scheduling information about its scheduled communication. Devices in the nearby network receive the broadcast and transfer the information to their controller. The controller then changes its network schedule to avoid interference. The technology does not require communication between the two controllers. In another embodiment, the device that detects the interference notifies its controller of the interference, and the controller communicates with a nearby controller to adjust the non-interference scheduling. The technology requires two controllers to communicate with each other. In either embodiment, it is necessary to reassign the functionality of the controller to another device, which can be a cumbersome and time consuming task.

Figure 1 shows a network diagram of two overlapping networks with interference between the networks. Network A includes the piconet controller PNC-A and three associated network devices A-1, A-2 and A-3 that are registered with PNC-A and whose communication can be substantially scheduled by PNC-A. To be equipped. Network B includes the piconet controller PNC-B and three associated network devices B-1, B-2 and B-3 that are registered with PNC-B and whose communication can be substantially scheduled by PNC-B. To be equipped. Each device in each network may have at least one antenna (s) for directional communication. Unless otherwise specified, some or all devices in each network may be battery-powered mobile devices. In the network configuration shown, device A-1, which is also under the range of controller PNC-B, can receive signals from both PNC-A and PNC-B, but typically from PNC-B. Ignore the signal. Similarly, device B-2 at the edge of the PNC-A range may be able to receive and decode signals from PNC-A, but usually ignores these signals.

Due to the expected frequency duplication in some types of networks, such as piconets, communication between devices in the network to reduce potential interference from or to other devices is possible. It may be directional. Devices with multiple antennas transmit slightly different signals from each antenna, combining them so that they are relatively strong in a particular direction and relatively weak in another, effectively directivity. It is possible to perform transmission with. Similarly, among the signals from each antenna, by processing the signal by a specific method such as separating the signal from a specific direction and minimizing the signal from another direction, the directivity can be improved for reception. Can have. It is possible to focus both transmission and reception in a particular direction by determining the particular parameters of the process through communication between two particular devices. This is commonly referred to as antenna training, and various antenna trainings are known. Antenna training is not detailed here as it is not part of the novelty of the embodiments of the invention described.

In the illustrated embodiment, device B-2 is directionally transmitting to device B-1 on network B, as indicated by the drop-shaped transmission envelope. At the same time, in network A, device A-2 is directionally transmitting to device A-1. However, due to the relative position of devices A-1, A-2, B-1 and B-2, device B-1 may receive signals from devices A-2 and B-2 at the same time. .. If A-2 and B-2 are transmitting at the same or similar frequencies, the signal received by A-2 to B-1 may interfere with the signal received by B-2 to B-1. .. For example, when A-1 / A-2 communication and B-1 / B-2 communication are repeated at regular intervals such as the same time slot in a repeated super frame, the interference is repeated for a long period of time. Communication from B-2 to B-1 may be difficult. Changing the time slot of any of these communications may solve the problem, but in traditional systems the time slot may be determined by a controller that does not know the mutual network schedule. is there.

FIG. 2 shows a network diagram that attempts to mitigate the interference of FIG. 1 according to an embodiment of the present invention. FIG. 3 shows a flow diagram 300 of the method associated with the network diagram of FIG. 2 according to an embodiment of the present invention. Both FIGS. 2 and 3 are referred to in the following description. In this embodiment, B-1 may determine in step 310 that there is interference from an adjacent network and in step 320 B-1 may broadcast a report containing information about the interference. The term "broadcast" as used herein indicates that the transmission is not directed to a particular device, but is intended to be received and processed by any receivable device. The term "report" herein may include any form suitable for reporting information intended to be communicated. In the example, the transmission is directional transmission as shown by the drop-shaped transmission envelope, but in other embodiments, other techniques such as omnidirectional transmission may be used. The broadcast is intended to be received by a device within network A, and in an exemplary embodiment, it is transmitted towards a presumed source of interference.

In some embodiments, the content of the transmission may be in a form designed to report information about interference. For example, but not limited to these, the format is (1) a field indicating that the transmission contains information about interference, (2) transmitting device identification information, (3) interfering device identification information (if known), It may include (4) interference occurrence time, (5) bit error rate, frame error rate, signal / noise ratio, signal parameters such as interference signal reception power, (6) piconet identification information, (7) others, etc. .. Also, in the interference report, future reception of the interfered device (eg B-1) in the hope that PNCs of other networks will readjust their network schedule to avoid future interference. A schedule may be included. In many networks, the schedules of the two network controllers are not synchronized, so simply showing the timing of interference within network B's superframe (and similarly network schedule within network B's superframe) is a PNC-A. May be inadequate for. Therefore, other information may be transmitted directly or indirectly in order to realize that the timing information about the device of one network is converted into the timing that is meaningful to another network. For example, a transmission from B-1 is the next super of network B, measured from a particular point in time of transmission (eg, at the beginning of a header, at the end of data, or any other point in time). It may contain information about the time the frame starts (eg, time offset). The information may then be added to the recorded receive time of the transmission to allow timing conversion between the superframes of the two networks to determine the next superframe start time for the transmitting device. Since the transmitting device and the receiving device are close to each other, the transit time of the transmitted signal is substantially instantaneous and may be ignored in the calculation.

In the examples of FIGS. 2 and 3, at step 330, A-2 may receive an interference notification and the upcoming schedule of device B-1, and then at step 350, any feasible allowed within network A. Information may be transferred to PNC-A via various communication formats. After PCN-A receives the report and reviews the information in step 370, PCN-A converts the reported network timing to its own network timing as described above in step 380, and PCN-A in step 390. A may reschedule the timing of future transmissions from device A-2 to device A-1 to avoid interference time periods within network B's superframe. In some embodiments, devices other than device A-1 are not found to cause interference with device B-1, so the timing of transmission from device A-2 to these devices is relevant. It does not have to change depending on the process. If a device other than device A-1 causes interference with other devices in network B, these devices may also report the information to PNC-A by performing the entire process shown in FIG.

Even if the broadcast from B-1 is directional transmission, it may be received by a device other than A-2. For example, device B-2 may also receive. However, since B-2 is in the same network as B-1 and the format of the transmission indicates that it is an interference report for another network, B-2 can simply ignore the report. In Figure 3, which shows the behavior of A-2 instead of device B-2, the option to discard reports sent from its own network is shown in steps 340 and 360, but similar options are for any non-PNC across the network. May be adopted by the device.

Another possibility is that another device on network A will also receive the transmission. For example, A-1 may be close enough to receive a message and device A-1 may be close to the transmit envelope of device B-1. In this case, device A-1 may also report information to PNC-A by performing steps 330, 340 and 350. PNC-A can process reports from device A-2 while simply ignoring redundant reports from device A-1.

Since the timing of the superframes of network A and network B is not synchronized from the beginning, it is unknown to device B-1 when the transmission is correctly received by the device of network A. For example, the interference report from device B-1 may be transmitted when device A-2 transmits to device A-3. Therefore, device A-2 cannot detect / decode the transmission from device B-1. Due to such uncertainty, interference reports from device B-1 may need to be retransmitted many times and even from different locations in the superframe until they are received correctly. In some embodiments, device A-2 may send an acknowledgment (ACK) to device B-1 if the interference report from device B-1 is successfully received. In another embodiment where there is no valid form of feedback between networks, B-1 has no way of completely knowing that the interference report was received correctly and can only infer this when the interference ceases.

FIG. 4 shows another network diagram that attempts to mitigate the interference of FIG. 1 according to an embodiment different from the embodiment of the present invention shown in FIG. FIG. 5 shows a flow diagram 500 of the method associated with the network diagram of FIG. 4 according to an embodiment of the present invention. Both FIGS. 4 and 5 are referred to in the following description. Similarly, in step 510, device B-1 may detect interference as it attempts to receive transmissions from devices in its network. Then, in step 520, an interference report may be sent to its own network controller PNC-B. The transmission may be a unicast transmission for PNC-B rather than a broadcast.

The transmission may be in a format specially designed to report such interference to PNC-B, but the format may differ from the format described for FIGS. 2 and 3. For example, since the future communication schedule of device B-1 is already known to PNC-B, the format may not include such information. However, but not limited to these, the format is (1) a field indicating that the transmission contains information about interference, (2) transmitting device identification information, (3) interfering device identification information (if known), Similar to the information in the examples of FIGS. 2 and 3 such as (4) interference occurrence time, (5) bit error rate, frame error rate, signal / noise ratio, signal parameters such as received power of interference signal, (6) others, etc. Other information may be included.

Upon receiving the report in step 530, PNC-B may establish a communication link with PNC-A in step 540. In step 550, the two PNCs may then exchange information about their respective network schedules, while both PNCs may readjust part of the network schedule to avoid reported interference. As mentioned above, the timing of the superframes of the two networks may not be synchronized, so a common timing criterion has been established by the two PNCs to enable conversion of the timing of the superframes between the two networks. Need to be done. When devices in multiple networks use directional transmission, in the specific interference example shown in Figure 1, B-2 to B-1 transmission and A-2 to A-1 transmission for rescheduling. You only have to consider.

In both the embodiments of FIGS. 2 and 3 and the embodiments of FIGS. 4 and 5, the network device that detected the interference reports the interference, but the reporting method differs depending on each embodiment. In the first method, the interference notification is broadcast in the direction of the interfering network along with the scheduled schedule of the device that detected the interference. The notification is received by a device in the interfering network and forwarded to the network controller in the interfering network. The network controller may then change its network schedule to avoid causing interference. In the second method, the interference is reported to the network controller associated with the device that detected the interference, which then contacts the other network controllers to negotiate a non-interfering schedule adjustment. The first method is excellent in that the two network controllers do not need to be able to communicate with each other and can be realized even if they are outside the range of each other. The first method, on the other hand, has the disadvantage that since only one PNC can adjust its network schedule, it is slightly less likely to be able to create a non-interfering schedule.

The above description is for illustrative purposes only and is not intended to be limiting. Those skilled in the art will come up with examples of changes. Such modifications are intended to be included in various embodiments of the present invention, and the present invention is limited only by the gist and scope of the following claims.<u style="single">[Item 1]</u><u style="single"> First communication device operating on the first wireless network</u><u style="single">With</u><u style="single"> The first communication device is a device that detects interference from a second wireless network during a scheduled reception time of the first wireless network and transmits a notification of the interference.</u><u style="single">[Item 2]</u><u style="single"> The device according to item 1, wherein the first communication device transmits the notification to the controller of the first wireless network.</u><u style="single">[Item 3]</u><u style="single"> The device according to item 2, wherein the notification includes at least one of the time of the interference and the identification information of the device causing the interference.</u><u style="single">[Item 4]</u><u style="single"> The device according to item 1, wherein the notification includes a broadcast of a communication schedule by the first communication device.</u><u style="single">[Item 5]</u><u style="single"> The device according to item 1, further comprising at least one antenna coupled to the first communication device.</u><u style="single">[Item 6]</u><u style="single"> The device according to item 1, wherein the first wireless network includes a piconet.</u><u style="single">[Item 7]</u><u style="single"> First network controller operating in the first wireless network</u><u style="single">With</u><u style="single"> The first network controller receives a notification of interference from the second wireless network to the first mobile device from the first mobile device in the first wireless network, and the second network controller of the second wireless network receives the notification. A device that notifies an interference and adjusts a network schedule with the second network controller to avoid the interference.</u><u style="single">[Item 8]</u><u style="single"> The device according to item 7, wherein the notification to the second network controller has at least one of the time indicator of the interference and the identification information of the interfering device in the second wireless network.</u><u style="single">[Item 9]</u><u style="single"> The device according to item 7, wherein the first wireless network and the second wireless network are piconets.</u><u style="single">[Item 10]</u><u style="single"> 1st network controller in 1st wireless network</u><u style="single">With</u><u style="single"> The first network controller receives a notification from the first mobile device in the first wireless network about interference from the first wireless network with the second mobile device in the second wireless network, and receives the notification from the first mobile device in the first wireless network, and the second mobile A device that receives a communication schedule scheduled by a device from the first mobile device and readjusts the network communication schedule within the first wireless network to avoid future interference with the scheduled communication.</u><u style="single">[Item 11]</u><u style="single"> The device according to item 10, wherein the notification has a time indicator of the interference.</u><u style="single">[Item 12]</u><u style="single"> The device according to item 10, wherein the notification has identification information of the second mobile device.</u><u style="single">[Item 13]</u><u style="single"> The step of detecting interference from the second wireless network to the first device during the scheduled reception time of the first wireless network by the first device in the first wireless network, and</u><u style="single"> In response to the detection, the step of transmitting the interference notification from the first device and</u><u style="single">How to prepare.</u><u style="single">[Item 14]</u><u style="single"> The method according to item 13, wherein the step of transmitting the notification includes a step of transmitting the notification to the controller in the first wireless network.</u><u style="single">[Item 15]</u><u style="single"> The method according to item 14, wherein the step of transmitting the notification to the controller includes a step of notifying the controller of the time of the interference.</u><u style="single">[Item 16]</u><u style="single"> The method according to item 13, wherein the step of transmitting the notification includes a step of broadcasting a schedule of communication by the first device.</u><u style="single">[Item 17]</u><u style="single"> The method according to item 16, wherein the step of broadcasting the schedule includes a step of broadcasting the identification information of the first device.</u><u style="single">[Item 18]</u><u style="single"> The stage of receiving a notification from the first device of the first wireless network about interference from the second wireless network to the first device by the first controller of the first wireless network, and</u><u style="single"> The stage of notifying the second controller of the second wireless network about the interference, and</u><u style="single"> The stage of adjusting the network schedule with the second controller to avoid the interference</u><u style="single">How to prepare.</u><u style="single">[Item 19]</u><u style="single"> The method of item 18, wherein the notifying step comprises providing a time indicator of the interference.</u><u style="single">[Item 20]</u><u style="single"> The method according to item 19, wherein the notification step includes a step of having identification information of an interfering device of the second wireless network.</u><u style="single">[Item 21]</u><u style="single"> The stage where the notification about the interference of the second wireless network with the first mobile device and the schedule of the reception time of the first mobile device are received by the first network controller in the first wireless network, and</u><u style="single"> The stage of readjusting the network communication schedule of the first wireless network in order to avoid the occurrence of further interference during the scheduled reception time.</u><u style="single">How to prepare.</u><u style="single">[Item 22]</u><u style="single"> The method according to item 21, wherein the receiving step includes a receiving step from the device of the first wireless network.</u><u style="single">[Item 23]</u><u style="single"> 22. The method of item 22, wherein the receiving step comprises receiving the notification and the schedule from two different devices in the first wireless network.</u><u style="single">[Item 24]</u><u style="single"> An article comprising a tangible computer-readable medium having instructions to perform an operation when executed by one or more processors.</u><u style="single"> The above operation</u><u style="single"> The step of detecting interference from the second wireless network to the first device during the scheduled reception time of the first wireless network by the first device in the first wireless network, and</u><u style="single"> In response to the detection step, the step of transmitting the interference notification from the first device</u><u style="single">Goods with.</u><u style="single">[Item 25]</u><u style="single"> The article according to item 24, wherein the step of transmitting the notification includes a step of transmitting the notification to a controller in the first wireless network.</u><u style="single">[Item 26]</u><u style="single"> The article according to item 25, wherein the step of transmitting the notification to the controller includes a step of notifying the controller of the time of the interference.</u><u style="single">[Item 27]</u><u style="single"> The article according to item 24, wherein the notifying step is a step of broadcasting a communication schedule by the first device.</u><u style="single">[Item 28]</u><u style="single"> The article according to item 27, wherein the stage of broadcasting the schedule includes a stage of performing directional transmission.</u><u style="single">[Item 29]</u><u style="single"> An article comprising a tangible computer-readable medium having instructions to perform an operation when executed by one or more processors.</u><u style="single"> The above operation</u><u style="single"> A stage in which the first controller of the first wireless network receives a notification from the first device of the first wireless network about interference from the second wireless network to the first device, and</u><u style="single"> The stage of notifying the second controller of the second wireless network about the interference, and</u><u style="single"> The stage of adjusting the schedule of the second controller and the network to avoid the interference</u><u style="single">Goods with.</u><u style="single">[Item 30]</u><u style="single"> 29. The article of item 29, wherein the notifying step is a step of transmitting the interference time indicator.</u><u style="single">[Item 31]</u><u style="single"> The article according to item 30, wherein the notification step includes a step including identification information of an interfering device of the second wireless network.</u><u style="single">[Item 32]</u><u style="single"> An article comprising a tangible computer-readable medium having instructions to perform an operation when executed by one or more processors.</u><u style="single"> The above operation</u><u style="single"> The stage where the notification about the interference of the second wireless network with the first mobile device and the scheduled reception time of the first mobile device are received by the first network controller in the first wireless network, and</u><u style="single"> The stage of readjusting the network communication schedule of the first wireless network in order to avoid the occurrence of further interference during the scheduled reception time.</u><u style="single">Goods with.</u><u style="single">[Item 33]</u><u style="single"> The article according to item 32, wherein the receiving step has a step of receiving from the device of the first wireless network.</u><u style="single">[Item 34]</u><u style="single"> 33. The article of item 33, wherein the receiving step includes a step of receiving from two different devices of the first wireless network.</u>