Patent Application
20250008491
Modern vehicles may include multiple battery cells. Information associated with the cells, such as temperature, voltage, and other indicators of cell status and health, may be monitored for vehicular safety and to ensure proper operation. In a conventional wired battery management system, rechargeable batteries are managed by circuitry for the safe and efficient operation of the batteries. Wired communication interfaces can be used to connect a main microcontroller (the main node or master node) to each battery module (the secondary nodes), and each battery module is chained to the rest of the battery modules in a daisy chain. With wired communication interfaces, the main microcontroller cannot monitor and control all the battery modules in parallel without complex wiring. This wiring makes repair or replacement of individual battery cells more difficult, and importantly, adds weight and bulk to the overall system.
A wireless connection between the battery modules and the microcontroller makes management of battery modules more flexible and easier to repair. In a wireless battery management system (WBMS), a microcontroller monitors each battery module and communicates with the battery modules using wireless communication interfaces. The main microcontroller controls all the battery modules using a WBMS protocol. Wireless communication interfaces can suffer from wireless communication channel bandwidth variance, interference, and/or other issues, which would prevent proper monitoring and management in a WBMS.
In accordance with at least one example of the description, a method includes receiving, in a super frame, a first downlink on a first channel from a wireless master node at a wireless head node in a WBMS, where the wireless head node is a head node for a sub-cluster of one or more wireless devices. The method also includes transmitting, in the super frame, a second downlink on a second channel from the wireless head node to each of the one or more wireless devices in the sub-cluster. The method includes receiving, in the super frame, an uplink from each of the one or more wireless devices at the wireless head node on the second channel. The method also includes transmitting, in the super frame, an aggregated uplink from the wireless head node to the wireless master node on the first channel, where the aggregated uplink includes data from each of the one or more wireless devices in the sub-cluster.
In accordance with at least one example of the description, a system includes a wireless head node in a WBMS, where the wireless head node is a head node for a sub-cluster of one or more wireless devices. The wireless head node is configured to receive, in a super frame, a first downlink on a first channel from a wireless master node. The wireless head node is also configured to transmit, in the super frame, a second downlink on a second channel to each of the one or more wireless devices in the sub-cluster. The wireless head node is configured to receive, in the super frame, an uplink from each of the one or more wireless devices on the second channel. The wireless head node is also configured to transmit, in the super frame, an aggregated uplink to the wireless master node on the first channel, where the aggregated uplink includes data from each of the one or more wireless devices in the sub-cluster.
In accordance with at least one example of the description, a system includes a first wireless head node in a WBMS, where the first wireless head node is a head node for a sub-cluster of one or more wireless devices. The first wireless head node is configured to receive, in a super frame, a first downlink on a first channel from a wireless master node. The first wireless head node is also configured to transmit, in the super frame, a second downlink on a configuration channel to each of the one or more wireless devices in the sub-cluster. The first wireless head node is configured to wait for a second wireless head node to transmit a third downlink on the configuration channel. The first wireless head node is also configured to receive, in the super frame, an uplink from each of the one or more wireless devices on a second channel. The first wireless head node is configured to transmit, in the super frame, an aggregated uplink to the wireless master node on the first channel, where the aggregated uplink includes data from each of the one or more wireless devices in the sub-cluster.
The same reference numbers or other reference designators are used in the drawings to designate the same or similar (functionally and/or structurally) features.
Some electronic devices operate using batteries. For example, electric vehicles include multiple battery cells that provide power to those vehicles. Because battery cells in an electronic device can provide large amounts of power, and further because the power provided by the battery cells may be vital to the operation of the electronic device, the electronic device may include a system to manage the battery cells.
Battery management systems (BMSs) may manage the battery cells of an electronic device in various ways. For example, a BMS may monitor the health (e.g., voltage, current, temperature) of battery cells in an electronic device. Further, the BMS may control various battery cells to manage the quantity of power provided by the battery cells and where that power is directed within the electronic device. Generally, a BMS includes multiple components, such as multiple battery modules and a controller to manage the battery modules. Each battery module, in turn, may couple to multiple battery cells and include a battery monitor to monitor those battery cells. Thus, the battery cells coupled to a battery module provide power to the electronic device; the battery monitor in the battery module monitors the health and operation of the battery cells in that battery module; and the controller communicates with the battery monitor to ensure the battery module and its cells are operating properly. The controller may also communicate with the battery monitor to control the operation of the battery cells, such as to turn on, turn off, redirect, or otherwise balance the power provided by those battery cells.
BMSs may incorporate wireless technology to create a wireless battery management system (WBMS). For example, a primary network node contains or is coupled to a controller and a secondary network node contains a battery module that controls multiple battery cells. The primary and secondary network nodes (e.g., the main/master node and the end nodes) may communicate with each other wirelessly, for example using radio frequencies. In some protocols, a super frame (SF) is useful to facilitate wireless communications between the primary and secondary network nodes. In the SF, the primary network node first broadcasts a downlink communication (or packet) to multiple secondary network nodes. The secondary network nodes individually respond to the primary network node with uplink communications (or packets) in a serial manner. Additional example details of WBMSs can be found in commonly assigned U.S. patent application Ser. No. 17/828,895, entitled “Efficient Unicast Super Frame Communications,” filed on May 31, 2022, which is incorporated by reference in its entirety.
In a WBMS, as the number of nodes increases, latency issues may occur. A primary network node that communicates directly with a large number of secondary network nodes receives individual responses from each secondary network node serially, and these response may take a large amount of time to transmit to the primary network node. The SF duration increases in size with the increase in the number of nodes. Also, in large networks, some secondary nodes may not be within communication range of the primary node.
In examples herein, a hierarchical WBMS network structure is described that can handle a large number of nodes with low latency and one-hop extension. A primary node (also referred to herein as a wireless master (WM)) operates as a master node for an entire network of nodes. The secondary nodes are divided into sub-clusters, with one or more secondary nodes in each sub-cluster. A secondary node in each sub-cluster operates as a wireless head (WH) node, and acts as a master node for the sub-cluster to which it belongs. The other secondary nodes in each sub-cluster are referred to as wireless devices (WD) herein. In some examples, a dedicated WH node may be used in the sub-cluster rather than selecting one of the WDs as the WH. The WM and the WHs use a master hopping sequence (MHS) to manage the communications channels used by the nodes.
In the hierarchical system described herein, the WM communicates with the WHs, and the WHs communicate with the WDs. The WM and the WDs do not generally communicate directly with one another, at least in some examples. The WM is in communication range with the WHs, and the WHs are in communication range with their respective WDs in their sub-cluster. The sub-clusters may have the same number of WDs, or the sub-clusters may have different numbers of WDs. A number of SF structures are described herein for managing communications between nodes arranged in the hierarchical system.
For a WBMS with a large number of nodes, the latency is reduced with the hierarchical system and SF structures described herein. Throughput is also increased due to the efficient SF structures. Low network restart times may be achieved, and power consumption may also be reduced in the examples herein. Moreover, it may be easier to re-establish communication with a WD using the techniques of this disclosure.
In an example, the primary network node 102 is coupled to the battery controller 104 using a first wired connection 110. In an example, the first wired connection 110 between the primary network node 102 and the battery controller 104 is a universal asynchronous receiver/transmitter (UART), inter-integrated circuit (I2C), or the like. The WHs in secondary network nodes 106 are wirelessly coupled to the primary network node 102 (e.g., the WM). The WHs and WDs in the secondary network nodes are coupled to the battery cells 108 using a second wired connection 112. Although
In an example, WBMS 100 provides wireless radio frequency (RF) communication between the primary network node 102 and the WHs of the secondary network nodes 106, and between the WHs and the WDs. In an example, the wireless RF communication uses the license-free 2.4 gigahertz (GHz) industrial, scientific, and medical (ISM) band from 2.4 GHz to 2.483 GHZ, which is compliant with BLUETOOTH special interest group (SIG). In examples, WBMS 100 uses 2 megabits per second (Mbps) BLUETOOTH low energy (BLE) across the physical layer (PHY). The Open Systems Interconnection (OSI) model includes the PHY as a layer used for communicating raw bits over a physical medium. In this case, the PHY is free space, which WBMS 100 uses to wirelessly communicate between the primary network node 102 and the WHs of the secondary network nodes 106. In an example, the transmission power of WBMS 100 is less than or equal to 10 decibel-milliwatts (dBm).
In an example, the wireless RF communication between the primary network node 102 and the WHs of the secondary network nodes 106 utilizes frequency hopping and time slotted allocations to transmit and receive data across SFs, as does the RF communication between the WHs and the respective WDs. An SF, also referred to as a super frame interval, is a time interval including time and frequency allocations for data exchanges between the primary network node 102 and the WHs of the secondary network nodes 106 (and between the WHs and the WDs), including interframe spacing between these allocations. Frequency hopping includes transmitting RF signals by rapidly changing the transmission frequency among many distinct frequencies occupying a spectral band. In an example, frequency hopping occurs based on a linear shift-back register and a master identification (ID) of the primary network node 102. The linear shift-back register uses linear bit rotation to indicate a pattern of frequencies on which the primary network node 102 and the secondary network nodes 106 will communicate. Time slotted allocations are time slots that are assigned either to the primary network node 102 or one or more of the secondary network nodes 106 for transmitting to either one or more of the secondary network nodes 106 or the primary network node 102. The time slotted allocations occur in a half-duplex mode, as both the primary network node 102 and the secondary network nodes 106 switch between transmit and receive modes according to the temporal moment specified in scan/pairing frames of exchanged data for downlink (DL)/uplink (UL) durations.
In an example, the WBMS 100 uses frequency division multiple access (FDMA) and changes the frequency at which frames are transmitted between the primary network node 102 and the respective secondary network nodes 106 (and between the WHs and the WDs) to increase robustness against interference. In an example, the WBMS 100 uses frequency hopping tables, black listing of frequencies, and configuration channels to mitigate interference with other wireless networks. Frequency hopping occurs on a per SF basis, where during the SF, time slotted allocations are used for frame exchange. Black listing is suspending the use of frequency channels that may be susceptible to interference. Configuration channels may be used for scanning, pairing, and negotiating communication between the primary network node 102 and the WHs of the secondary network nodes 106, and between the WHs and the WDs.
In an example, the wireless RF communication between the primary network node 102 and the secondary network nodes 106 uses 40 channels, where a subset of the 40 channels (e.g., channels 37, 38, and 39) is used for system configuration and the remaining 37 channels are used to exchange data. The WHs may also communicate with the WDs using configuration channels and data channels. In an example, a single channel may be used as a configuration channel.
In an example, WBMS 100 supports periodic and a-periodic data exchanges from the secondary network nodes 106 to the primary network node 102 using wireless RF communication, and between the WHs and the WDs. The primary network node 102 and the secondary network nodes 106 use a common data format structure for both periodic and a-periodic data exchanges. Periodic data exchange occurs based on a repetitive interval, while a-periodic data exchange does not occur based on a repetitive interval. The data format is a description of rules that the data populating a file will follow. Generally, the more thorough the description of the data format, the easier it is for validation rules to be written on both the sending and receiving sides of the wireless battery management system 100.
In an example, the primary network node 102 scans the network to obtain a master ID and discover the secondary network nodes 106 or the WHs of the secondary network nodes 106. The primary network node 102 scans the network by transmitting a management frame to coordinate medium access, wakeup schedules, and clock synchronization within the secondary network nodes 106. The primary network node 102 also uses the management frame to learn about the secondary network nodes 106 in the network. Initially, the primary network node 102 performs a passive scan to obtain (or check for) a master ID value in use by other nodes and/or devices. The primary network node 102 then selects a master ID that is different from the master IDs used by other nodes and/or devices.
In an example, after the primary network node 102 has selected a master ID, the primary network node 102 transmits a scan request frame in every SF period as long as there are unconnected secondary network nodes 106 from the primary network node 102. In an example, the primary network node 102 is programmed with the total number of the secondary network nodes 106 to be connected to the primary network node 102. After all the secondary network nodes 106 are connected and confirmed, the primary network node 102 will not transmit any more scan requests. The scan request frames include information about the structure of the SF and the frame formatting of the DL and UL slots.
For the primary network node 102 to scan for the secondary network nodes 106, the primary network node 102 enters a scan state. In this state, the primary network node 102 transmits a scan request frame in every SF period. The secondary network nodes 106 reply to the primary network node 102 with a scan response and await a pairing request frame from the primary network node 102. After the secondary network nodes 106 receive the pairing request, the secondary network nodes 106 respond within the same SF in the frequency slot assigned by the primary network node 102. In examples, this exchange occurs in the configuration channels. No data exchanges occur in this state. Additional example details of establishing a communication channel can be found in commonly assigned U.S. Patent Application Publication No. 2022/0332213, entitled “Wireless Protocol for Battery Management,” filed on Apr. 16, 2021; and U.S. Patent Application Publication No. 2023/0051689, entitled “Wireless Battery Management System Setup,” filed on Aug. 11, 2021, each of which is incorporated by reference in its entirety.
In an example, transmission cycles or SFs depend on the number of secondary network nodes 106 and/or battery cells 108 in the network. The primary network node 102 determines the SF interval based on the number of secondary network nodes 106 or the number and size of the sub-clusters as described herein. Given a number of secondary network nodes 106 and/or sub-clusters, the primary network node 102 estimates the number of DL slots usable to transmit the packets to the secondary network nodes 106.
WBMS 100 manages the battery cells 108 using the primary network node 102, the battery controller 104, and the secondary network nodes 106. The primary network node 102 and the secondary network nodes 106 (e.g., the WHs) communicate with each other about the state of the battery cells 108. The primary network node 102 and the secondary network nodes 106 may communicate with or among each other using various protocol formats. For example, the primary network node 102 and the secondary network nodes 106 use a DL protocol format and a UL protocol format, where each of the DL protocol format and the UL protocol format includes a frame control field to communicate battery management information. When the battery cells 108 notify the secondary network nodes 106 of a condition, the secondary network nodes 106 communicate to the primary network node 102 (or to the respective WH of the sub-cluster) that the condition is present. The primary network node 102 receives the notification of the condition from the secondary network nodes 106 (e.g., the WHs) and alerts the battery controller 104 of the condition. The battery controller 104 determines a proper reaction to the condition and sends an instruction to the primary network node 102. The primary network node 102 transmits the instruction to the secondary network nodes 106 (e.g., the WHs). The WHs transmit the instructions to the WDs in the sub-clusters. The secondary network nodes 106 receive the instruction to manage the battery cells 108 in response to the condition. The secondary network nodes 106 manage the battery cells 108 in response to the condition.
The primary network node 102 (if it is a WM) is coupled to the battery controller 104 using the first wired connection 110 and is wirelessly coupled to each of the secondary network nodes 206, 210. The first secondary network node 206 is coupled to the first plurality of battery cells 208 using a third wired connection 214 and wirelessly coupled to the primary network node 102. The second secondary network node 210 is coupled to the second plurality of battery cells 212 using a fourth wired connection 216 and wirelessly coupled to the primary network node 102.
In an example, the primary network node 102 is wirelessly coupled to at least eight secondary network nodes 206, 210. In an example, each of the secondary network nodes 206, 210 can be coupled to at least sixteen battery cells using a wired connection. In examples, the wireless battery management system 200 includes one primary network node. In other examples, the wireless battery management system 200 includes multiple primary network nodes, with each network having its own hierarchical structure.
WBMS 200 manages the first plurality of battery cells 208 and the second plurality of battery cells 212 using the primary network node 102, the battery controller 104, the memory 202, the processor 204, the first secondary network node 206, and the second secondary network node 210. Instructions in the memory 202 cause the processor 204 to instruct the primary network node 102 to wirelessly communicate with the first secondary network node 206 and the second secondary network node 210 about the state of the first plurality of battery cells 208 and the second plurality of battery cells 212. The primary network node 102 and the secondary network nodes 206, 210 communicate using various protocol formats. For example, the primary network node 102 and the secondary network nodes 206, 210 use a DL protocol format and a UL protocol format, where each of the DL protocol format and the UL protocol format includes a frame control field to communicate battery management information. When the first plurality of battery cells 208 notify the first secondary network node 206 of a condition, the first secondary network node 206 communicates with the primary network node 102 (or with a WH) that the condition is present. The primary network node 102 (or the WH) receives the notification of the condition from the first secondary network node 206 and alerts the battery controller 104 (or the WM) of the condition. The battery controller 104 determines a proper reaction to the condition and sends an instruction to the primary network node 102. The primary network node 102 transmits the instruction to the first secondary network node 206 (or to the WHs). The first secondary network node 206 receives the instruction to manage the first plurality of battery cells 208 in response to the condition of the first plurality of battery cells 208. The first secondary network node 206 manages the first plurality of battery cells 208 in response to the condition. A similar process may apply to the second secondary network node 210 when a condition is present in the second plurality of battery cells 212. As described herein, with the hierarchical structure, the WM communicates with the WHs, and the WHs communicate with the respective WDs and then relay the responses from the WDs back to the WM.
The plurality of primary network nodes 252 are coupled to the plurality of battery controllers 260 using the first wired connection 258 and are wirelessly coupled to the secondary network node 206. The first secondary network node 206 is coupled to the first plurality of battery cells 208 using the wired connection 214 and wirelessly coupled to the plurality of primary network nodes 252. As shown in
WBMS 250 manages the first plurality of battery cells 208 using the plurality of primary network nodes 252, the plurality of battery controllers 260, the memory 254, the processor 256, and the first secondary network node 206. Instructions in the memory 254 cause the processor 256 to instruct the plurality of primary network nodes 252 to wirelessly communicate with the first secondary network node 206 about the state of the first plurality of battery cells 208. The plurality of primary network nodes 252 and the first secondary network node 206 communicate using various protocol formats. For example, the plurality of primary network nodes 252 and the first secondary network node 206 use a DL protocol format and a UL protocol format, where each of the DL protocol format and the UL protocol format includes a frame control field to communicate battery management information. When the first plurality of battery cells 208 notify the first secondary network node 206 of a condition, the first secondary network node 206 communicates with the plurality of primary network nodes 252 that the condition is present. The plurality of primary network nodes 252 receives the notification of the condition from the first secondary network node 206 and alerts the plurality of battery controllers 260 of the condition. The plurality of battery controllers 260 determines a proper reaction to the condition and sends an instruction to the plurality of primary network nodes 252. The plurality of primary network nodes 252 transmits the instruction to the first secondary network node 206. The first secondary network node 206 receives the instruction to manage the first plurality of battery cells 208 in response to the condition of the first plurality of battery cells 208. The first secondary network node 206 manages the first plurality of battery cells 208 in response to the condition.
In an example, the first secondary network node 206 communicates with a first primary network node of the plurality of primary network nodes 252 based on instructions from a master controller (not shown). The first secondary network node 206 can transition communication from the first primary network node to a second primary network node of the plurality of primary network nodes 252. The first primary network node and the second primary network node communicate with each other to coordinate transferring the active connections of the first secondary network node 206 from the first primary network node to the second primary network node. In an example, the first primary network node communicates with the first secondary network node 206 and the second primary network node monitors a status of the first primary network node. The status can indicate whether the first primary network node has power and is operating within normal operating conditions. The first primary network node provides a clock signal to the second primary network node to synchronize communication. The first primary network node and the second primary network node select different frequencies to communicate with the first secondary network node 206. Selecting different frequencies allows the plurality of primary network nodes 252 to minimize interference when communicating to the first secondary network node 206. For example, if the first primary network node were to lose power, or if the status of the first primary network node were to fall out of normal operating conditions, then the second primary network node can connect to the first secondary network node 206 to supplement communication until the first primary network node can operate normally again.
Each sub-cluster 304 has a WH 306 that manages the sub-cluster 304. Four WHs 306 are shown in
In this example, WH1306.1 manages WDs 308.1 to 308.6 in sub-cluster 304.1. Six WDs 308 are shown in sub-cluster 304.1 (e.g., WDs 308.1 to 308.6), but any number of WDs 308 may be present in the sub-clusters 304 in other examples. Sub-cluster 304.2 includes WH2306.2 and WDs 308.7 to 308.12. Sub-cluster 304.3 includes WH3306.3 and WDs 308.13 to 308.18. Sub-cluster 304.N includes WHN 306.N (where N may be any number) and WDs 308.19 to 308.24. In some examples, a WH 306 may also operate as a WD 308 and perform the monitoring and managing of a battery cell 108 that the WD 308 performs, in addition to the WH communication functionality that is described herein. However, this monitoring functionality is not contemplated for WHs 306 in all examples of this disclosure.
In examples herein, when installed in a WBMS, WM 302 is in communication range with the WHs 306, and each WH 306 is in communication range with its respective WDs 308 in its sub-cluster 304. The sub-clusters 304 may have the same number of WDs 308 or a different number of WDs 308. Six WDs 308 are shown in each sub-cluster 304 in this example, but other numbers may be present in other examples. As described below, the WM 302, WHs 306, and WDs 308 may use a master hopping sequence for selecting channels for communication. Also, as described below, various super frame structures are described below to handle communications within a hierarchical WBMS as described herein.
Super frame structure 400A includes a first super frame 402A, and super frame structure 400B includes a second super frame 402B. Super frame structures 400A and 400B includes various ULs and DLs 404 to 454. These ULs and DLs represent the communications between the devices in an example WBMS (e.g., WBMS 300). The details of each of the ULs and DLs 404 to 454 are described below.
Super frame structures 400A and 400B also show the channels that the devices in WBMS 300 are using for communication. In the first super frame 402A, channels M1, A1, and B1 are used. In the second super frame 402B, channels M2, A2, and B2 are used. The particular ULs and DLs that are transmitted on each channel are described below.
In WBMS 300, WM 302 communicates with WHs 306. WM 302 may send instructions or requests for battery cell information or battery management information to WHs 306. WHs 306 receive the instructions or requests, and then send instructions or requests to each WD 308 managed by the respective WH 306. The WDs 308 collect information (if needed) and respond to the WH 306 that manages the respective sub-cluster 304. Then, each WH 306 may be configured to aggregate the responses from the WDs 308 in its respective sub-cluster 304 and transmit a response to the WM 302. Therefore, the WHs 306 may be configured to act as intermediaries between the WM 302 and the WDs 308.
Responsive to DL 404, each WH 306 sends a DL to the WDs 308 in its respective sub-cluster 304. In this example, WH1306.1 transmits a DL 408 (DL WH1) to WD2 through WD7308. DL 408 is transmitted on channel A1. WH1306.1 uses channel A1 to communicate with its WDs 308 in first super frame 402A. WH2306.2 transmits a DL 410 (DL WH2) to WD9 through WD14308. DL 410 is transmitted on channel B1. WH2306.2 uses channel B1 to communicate with its WDs 308 in first super frame 402A. In this example, each sub-cluster 304 uses a different channel for communications between the WH 306 and the WDs 308 in the sub-cluster 304.
Each WD 308 receives the DL (408 or 410 in this example) from its respective WH 306. Only WD2308.2 and WD14308.14 are shown in
After receiving ULs from each WD 308 in its sub-cluster, each WH 306 aggregates the information in the ULs from the WDs 308 in its sub-cluster and sends an UL to WM 302. Here, WH1306.1 sends UL 424 to WM 302 on channel M1. WH2306.2 sends UL 426 to WM 302 on channel M1. ULs 424 and 426 are sent at different times on channel M1 as shown, so they do not interfere with one another. WM 302 receives ULs 428A-428D from each WH 306 that it manages. At this time, first super frame 402A is complete and second super frame 402B begins.
In second super frame 402B in
In second super frame 402B, WM 302 sends a DL 430 (DL-WM) on channel M2 to each of the WHs 306. In this case, WH1306.1 receives the DL 432A, and WH2306.2 receives the DL 432B. After WM 302 sends this DL 430, WM waits for the WHs 306 to receive responses from the WDs 308 and then provide those responses to WM 302.
Responsive to DL 430, each WH 306 sends a DL to the WDs 308 in its respective sub-cluster 304. In this example, WH1306.1 transmits a DL 434 (DL WH1) to WD2 through WD7308. DL 434 is transmitted on channel A2. WH2306.2 transmits a DL 436 (DL WH2) to WD9 through WD14308. DL 436 is transmitted on channel B2.
Each WD 308 receives the DL (434 or 436 in this example) from its respective WH 306. WD2308.2 receives DL 438, and WD14308.14 receives DL 440. Each WD 308 responds to its respective WH 306 with an UL. Here, WD2308.2 sends UL 442 to WH1306.1 on channel A2. WD14308.14 sends UL 444 to WH2306.2 on channel B2.
After receiving ULs from each WD 308 in its sub-cluster, each WH 306 aggregates the information in the ULs from the WDs 308 in its sub-cluster and sends an UL to WM 302. Here, WH1306.1 sends UL 450 to WM 302 on channel M2. WH2306.2 sends UL 452 to WM 302 on channel M2. WM 302 receives ULs 454A-454D from each WH 306 that it manages. At this time, second super frame 402B is complete and another super frame 402 may begin. The next super frame may hop channels again according to a master hopping sequence, and use channels M3, A3, and B3 for communication.
With the channel hopping sequence described herein, channels A and B could be derived from channel M using a set offset. For example, channel A could be found by calculating M-2, and channel B could be found by calculating M−4. Any other offset could be useful in other examples. Also, channel A or channel B could be channel M in one example. As shown in
Any suitable process may be used for network formation in examples herein. In one example, WM 302 forms a network with all WHs 306 in a first phase. In the second phase, each WH 306 forms a network with its respective WDs 308.
The network topology may be provided by one of two examples. In the first example, WM 302 is aware of the network topology before formation. The other nodes are informed of the network topology during the scanning phase. The network topology may be enforced by whitelisting selected nodes according to the topology. In this example, only WHs 306 are allowed to pair with WM 302. Paired WHs 306 receive the list of respective WDs 308 with which to form sub-clusters 304. A WH 306 may be configured to whitelist only the list of received WDs 308 for its sub-cluster 304 to form the sub-cluster 304.
In the second example, every node is programmed with the clusterID it is supposed to join before network formation. Each WH 306 (and the WM 302) are programmed (before network formation) with the clusterIDs that each are going to be the master for. WM 302 is programmed with the clusterIDs of each WH 306, and each WH 306 is programmed with the clusterIDs of the respective WDs 308 in its sub-cluster 304. The clusterID is advertised in the scan requests. If any node receives a scanning request, that node sends a response only if the clusterID in the request matches.
Network formation may be performed in two phases. In phase one, WM 302 may be configured to perform a passive scan to select its Master ID. WDs 308 may be configured to refrain from taking part in phase one, which may be enforced by whitelisting at WM 302. The super frame format used may be a Type 1 format, which is described below. Scanning and pairing are performed for the WHs 306 to pair with WM 302. The scanning may be performed using configuration channels in one example. After phase one is complete, WM 302 switches the network to the master hopping sequence for the data channels. After the WHs 306 are paired with WM 302, phase two begins.
In phase two, WM 302 coordinates the WHs 306 to form their respective sub-clusters 304 through their own scanning and pairing phases. A dedicated hopping sequence is communicated to each paired WH 306 by WM 302 to use within mini-super frames for data exchange. The hopping sequence (described below) may be selected from a set of orthogonal hopping sequences or shifted hopping sequences. A super frame Type 2 structure may be used throughout for network formation and operation. Three options are described below for network formation: Options 1, 2, and 3. Option 3 introduces an extra super frame type, Type 3. The different options may have different speeds for network formation, with some options being faster than other options. However, the faster options may also be more complex than the slower options.
In the Type 1 super frame, the super frame duration includes 1 DL slot and N UL slots, where N is the number of WHs 306 managed by a WM 302. The Type 1 super frame may be useful in the WH 306 scanning and pairing phases described herein. In super frame 502A, WM 302 sends a DL scan request 506 on configuration channel 1 504A. WHs 306 may respond on configuration channel 1 504A in super frame 502A. In this example, WH4 sends a UL 508 scan response to WM 302. WH2 sends a UL 510 scan response to WM 302.
In super frame 502B, WM 302 sends a DL scan request 512 on configuration channel 2 504B. WHs 306 may respond on configuration channel 2 504B in super frame 502B. In this example, WH5 sends a UL 514 scan response to WM 302. WH1 sends a UL 516 scan response to WM 302.
In examples herein, for each sub-cluster 304, WM 302 conveys the master hopping sequence and a unique offset to calculate the channel. The offset for a given sub-cluster 304 is subtracted from the channel number and wraps around over [0-36]. The offset also excludes the configuration channels 37, 38, and 39. For example, if a section of the master hopping sequence is for non-adjacent channels [5, 27, 0, 16] and the offset for a sub-cluster 304 is 3, the sub-cluster will follow channels [2, 24, 34, 13] while the MHS follows channels [5, 27, 0, 16]. The offset should be large enough to minimize adjacent channel interference. WM 302 needs to send only the master hopping sequence and the offsets to the WHs 306 in this example.
In some examples herein, measurement instant mismatch could occur due to the hierarchical structure. As an example, WM 302 may send an instruction to perform a measurement to the WHs 306, which in turn send that instruction to the WDs 308 in the respective sub-clusters 304. Therefore, the WHs 306 receive the instruction before the WDs 308. If the WHs perform the measurement before the WDs, measurement instant mismatch would occur, where the measurements for each node are not performed at the same time. Depending on the measurement performed, this mismatch could produce inaccurate data. In an example herein, the instructions may be delayed (e.g., in software) at the WHs 306 by an appropriate duration, so the measurements taken by the WHs 306 occur approximately at the same time as the measurements taken by the WDs 308.
In examples herein, each WH 306 receives data from N WDs 308 and forwards the aggregate data to WM 302 in its own timeslot (e.g., ULs 424 and 426 in
In this example, during Type 1 super frame 704A in
During Type 1 super frame 704B in
During Type 1 super frame 704C in
In each Type 2 super frame in this example, the corresponding WH 306 reports back to WM 302 the status of its sub-cluster 304 formation. After a WH 306 (e.g., WHN) completes forming its sub-cluster 304, WM 302 instructs the next WH 306 (e.g., WH(N+1)) to form its cluster beginning from the next Type 2 super frame. After any sub-cluster 304 is formed, that sub-cluster 304 switches to its hopping sequence derived from the master hopping sequence. The sub-cluster 304 is then in the network operation phase, where it participates in normal data exchange as described above with respect to
Super frame structures 800A and 800B show an example of Option 1 network formation. Super frame structure 800A includes super frame 802A, and super frame structure 800B includes super frame 802B, which are Type 2 super frames. In super frame 802A, WH1306.1 is in the network formation phase. WH2306.2 has already completed its network formation, and is in the normal data exchange phase. The process begins with WM 302 sending DL 804 to each WH 306 in the cluster. WH1306.1 receives DL 806A, and WH2306.2 receives DL 806B in this example. DL 804 contains an indication that WH1306.1 is in the scanning phase, and WH2306.2 has completed network formation. Other WHs 306 that have not completed their scanning phase will wait for WH1306.1 to complete its scanning phase. Other WHs 306 that have completed their scanning phases may engage in normal data exchange operation, such as WH2306.2 in this example. DL 804 may also contain an acknowledgement for UL frames from all WHs 306.
WH1306.1 then conducts its scanning phase. WH1306.1 transmits a scan request DL 808 to each WD 308 in its respective sub-cluster 304 on configuration channel 1. As shown, a WD 308 in this sub-cluster (such as WD2308.2) receives the scan request in DL 810. The WDs 308 in the sub-cluster for WH1306.1 then send individual responses back to WH1306.1 on configuration channel 1. In super frame 802A, a WD3308 sends UL 812 to WH1306.1, and a WD5308 sends UL 814 to WH1306.1. ULs 812 and 814 are not sent by WD2308.2, but are shown on the row for WD2308.2 for simplicity. WH1306.1 receives these responsive ULs 816 and 818, respectively. WH1306.1 aggregates the responses from its WDs 308 and transmits those to WM 302 with UL 820 on channel M1. UL 820 may note that WH1306.1 is in the scanning phase, and include an acknowledgement for the last frame from WM 302.
While WH1306.1 is scanning in super frame 802A, WH2306.2 is performing the normal data exchange with the WDs 308 in its sub-cluster. WH2306.2 transmits a DL 822 on channel B1. In this example, WDs 308.9 to 308.14 are in the sub-cluster 304 managed by WH2306.2. Only WH14308.14 is shown here for simplicity. Each WD 308 in this sub-cluster 304 receives a DL on channel B1, such as DL 824 received by WD14308.14. Each WD 308 sends a response to WH2306.2, such as the UL 826 from WD14308.14. WH2306.2 receives ULs 828A-828F from the WDs 308 in its sub-cluster 304 on channel B1. WH2306.2 aggregates the responses and provides a UL 830 to WM 302 on channel M1. UL 830 may indicate that WH2306.2 has completed its network formation phase, and contains aggregated data from WDs 308 in the respective sub-cluster 304. UL 830 may also include an acknowledgement for the last frame from WM 302. ULs 832A-832D are received at WM 302 in this example, but the system may include any number of sub-clusters 304 and WHs 306. This marks the end of super frame 802A.
In super frame 802B in
WM 302 sends DL 834 to each WH 306 in the cluster on channel M2. WH1306.1 receives DL 836A, and WH2 receives DL 836B in this example. DL 834 may be similar to DL 804 described above.
WH1306.1 transmits a scan request DL 838 to each WD 308 in its respective sub-cluster 304 on configuration channel 2. As shown, a WD 308 in this sub-cluster (such as WD2308.2) receives the scan request in DL 840. The WDs 308 in the sub-cluster for WH1306.1 then send individual responses back to WH1306.1 on configuration channel 2, for those WDs 308 that did not pair with WH1306.1 in a previous sub frame 802. In super frame 802B, a WD2308.2 sends UL 842 to WH1306.1, and a WD4308 sends UL 844 to WH1306.1. WH1306.1 receives these responsive ULs 846 and 848, respectively. WH1306.1 aggregates the responses from its WDs 308 and transmits those to WM 302 with UL 850 on channel M2. UL 850 may be similar to UL 820 described above.
While WH1306.1 is scanning in super frame 802B, WH2306.2 is performing the normal data exchange with the WDs 308 in its sub-cluster, as it did in super frame 802A. WH2306.2 transmits a DL 852 on channel B2. Each WD 308 in the sub-cluster 304 managed by WH2306.2 receives a DL on channel B2, such as DL 854 received by WD14308.14. Each WD 308 sends a response to WH2306.2, such as the UL 856 from WD14308.14. WH2306.2 receives ULs 858A-858F from the WDs 308 in its sub-cluster 304 on channel B2. WH2306.2 aggregates the responses and provides a UL 860 to WM 302 on channel M2. UL 860 may be similar to UL 830 described above. ULs 862A-862D are received at WM 302 in this example, but the system may include any number of sub-clusters 304 and WHs 306. This marks the end of super frame 802B.
Sub-cluster 304 formation in Option 2 is coordinated by WM 302. Each WH 306 is instructed to use one of the configuration channels by WM 302, and the configuration channels will be rotated each super frame. A similar scanning and pairing mechanism as described above in Option 1 may be used for each sub-cluster 304 in the configuration channels. The cluster uses the master hopping sequence as described herein. In each Type 2 super frame, the corresponding WHs 306 report back to WM 302 the status of their sub-cluster 304 formation. After any of the current three sub-clusters 304 are formed, WM 302 instructs a new WH 306 or a new set of WHs 306 to begin network formation. After any sub-cluster is 304 is formed, that sub-cluster 304 switches to its derived hopping sequence derived from the master hopping sequence for normal data exchange. Option 2 may be three times as fast as Option 1, but uses the same super frame structure and timing.
Super frame structures 900A and 900B show an example of Option 2 network formation. Super frame structure 900A includes super frame 902A, and super frame structure 900B includes super frame 902B, which are Type 2 super frames. In super frame 902A, WH1306.1, WH2306.2, and WH4306.4 are in the network formation phase. WH3306.3 has already completed its network formation, and is in the normal data exchange phase. In this example, no WDs 308 are shown, but the WHs 306 communicate with the WDs 308 in their respective sub-clusters 304 as described above with Option 1.
For Option 2, the process begins in super frame 902A with WM 302 sending DL 904 to each WH 306 in the cluster. WH1306.1 receives DL 906A, WH2306.2 receives DL 906B, WH3306.3 receives DL 906C, and WH4306.4 receives DL 906D. DL 904 from WM 302 contains an indication that WH1306.1. WH2306.2, and WH4306.4 are in the scanning or network formation phase, and WH3306.3 has completed network formation. WM 302 assigns the selected configuration channels to WH1306.1. WH2306.2, and WH4306.4. WH3306.3 follows the master hopping sequence. Other WHs 306 that have not yet formed their networks will not transmit until WM 302 assigns them a configuration channel.
Each WH 306 in the network formation phase transmits a scan request DL to each WD 308 in its respective sub-cluster 304 on its respective configuration channel. WH1306.1 sends DL 908 on configuration channel 1, WH2306.2 sends DL 910 on configuration channel 2, and WH4306.4 sends DL 912 on configuration channel 3. Then the WDs 308 (not shown) for each WH 306 respond with ULs back to their respective WHs 306 for pairing. In this example, WH1306.1 receives ULs 914A and 914B from its WDs 308, WH2306.2 receives ULs 914C and 914D from its WDs 308, and WH4306.4 receives ULs 914E and 914F from its WDs 308. Then, each WH 306 aggregates the ULs it received from its WDs 308 and transmits a UL to WM 302 on channel M1. Here, WH1306.1 sends UL 916, WH2306.2 sends UL 918, and WH4306.4 sends UL 920.
During super frame 902A, while WH1306.1, WH2306.2, and WH4306.4 are in the scanning phase, WH3306.3 is performing normal data exchange with its WDs 308. WH3306.3 transmits a DL 922 to its WDs 308 on channel B1. The WDs 308 respond to WH3306.3 with ULs 924A to 924F on channel B1. WH3306.3 aggregates the responses from the WDs 308 and transmits UL 926 to WM 302. UL 926 indicates that WH3306.3 has ended its network formation phase and includes aggregated data from all WDs 308 in WH3's 306.3 sub-cluster. WM 302 receives ULs 928A-928D (one from each WH 306 in the cluster) and super frame 902A ends.
In super frame 902B in
The process in super frame 902B begins with WM 302 sending DL 930 to each WH 306 in the cluster on channel M2. WH1306.1 receives DL 932A, WH2306.2 receives DL 932B, WH3306.3 receives DL 932C, and WH4306.4 receives DL 932D. DL 930 may be similar to DL 904 described above.
Each WH 306 in the network formation phase transmits a scan request DL to each WD 308 in its respective sub-cluster 304 on its respective configuration channel. WH1306.1 sends DL 934 on configuration channel 2, WH2306.2 sends DL 936 on configuration channel 3, and WH4306.4 sends DL 938 on configuration channel 1. Then the WDs 308 (not shown) for each WH 306 respond with ULs back to their respective WHs 306 for pairing. In this example, WH1306.1 receives ULs 940A and 940B from its WDs 308, WH2306.2 receives ULs 940C, 940D, and 940E from its WDs 308, and WH4306.4 receives ULs 940F, 940G, and 940H from its WDs 308. Then, each WH 306 aggregates the ULs it received from its WDs 308 and transmits a UL to WM 302 on channel M2. Here, WH1306.1 sends UL 942, WH2306.2 sends UL 944, and WH4306.4 sends UL 946.
During super frame 902B, while WH1306.1, WH2306.2, and WH4306.4 are in the scanning phase, WH3306.3 is performing normal data exchange with its WDs 308 (similar to super frame 902A). WH3306.3 transmits a DL 948 to its WDs 308 on channel B2. The WDs 308 respond to WH3306.3 with ULs 950A to 950F on channel B2. WH3306.3 aggregates the responses from the WDs 308 and transmits UL 952 to WM 302. WM 302 receives ULs 954A-954D (one from each WH 306 in the cluster) and super frame 902B ends.
Option 2 in
Super frame structures 1000A and 1000B show an example of Option 3 network formation. Super frame structures 1000A and 100B include super frames 1002A and 1002B, respectively, which are Type 3 super frames. In super frame 1002A, WH1306.1, WH2306.2, WH3306.3, and WH4306.4 are in the network formation phase. In this example, no WDs 308 are shown, but the WHs 306 communicate with the WDs 308 in their respective sub-clusters 304 as described above with Options 1 and 2.
For Option 3, the process begins in super frame 1002A in
Each WH 306 in the network formation phase transmits a scan request DL to each WD 308 in its respective sub-cluster 304 on its respective configuration channel. WH1306.1 sends DL 1008 on configuration channel 1, WH2306.2 sends DL 1010 on configuration channel 2, and WH3306.3 sends DL 1012 on configuration channel 3. Because there are four WHs 306 but only three configuration channels, WH4306.4 must wait in a waiting period 1014 for a configuration channel to become available. After DLs 1008, 1010, and 1012 are sent, the configuration channels are open, and WM 302 assigns configuration channel 1 to WH4306.4. WH4306.4 then sends DL 1016 to its WDs 308 in its sub-cluster 304. During the time that DL 1016 is transmitted, the other WHs 306 wait for DL 1016 to conclude. These waiting periods are shown as 1018A, 1018B, and 1018C for the first three WHs 306.
After the scan request DLs are sent to WDs 308, the WDs 308 respond to their respective WH 306 in the mini super frame. For this response, data channels are used rather than configuration channels. WH1306.1 uses channel A1, WH2306.2 uses channel B1, WH3306.3 uses channel C1, and WH4306.4 uses channel D1. WH1306.1 receives ULs 1020 and 1022, WH2306.2 receives ULs 1024 and 1026, WH3306.3 receives ULs 1028 and 1030, and WH4306.4 receives ULs 1032 and 1034.
After the ULs have been received by the WHs 306 from the WDs 308, each WH 306 aggregates the responses from its WDs 308 and sends a UL to WM 302 on channel M1. WH1306.1 sends UL 1036, WH2306.2 sends UL 1038, WH3306.3 sends UL 1040, and WH4306.4 sends UL 1042. WM 302 receives ULs 1044A-1044D, and super frame 1002A concludes.
Super frame 1002B in
The process begins in super frame 1002B with WM 302 sending DL 1046 to each WH 306 in the cluster. WH1306.1 receives DL 1048A, WH2306.2 receives DL 1048B, WH3306.3 receives DL 1048C, and WH4306.4 receives DL 1048D. DL 1004 from WM 302 contains an indication that WH1306.1, WH2306.2, WH3306.3, and WH4306.4 are in the scanning or network formation phase. WM 302 assigns the selected configuration channels and data channels to WH1306.1, WH2306.2, WH3306.3, and WH4306.4.
Each WH 306 in the network formation phase transmits a scan request DL to each WD 308 in its respective sub-cluster 304 on its respective configuration channel. WH1306.1 sends DL 1050 on configuration channel 2, WH2306.2 sends DL 1052 on configuration channel 3, and WH3306.3 sends DL 1054 on configuration channel 1. WH4306.4 waits in a waiting period 1056 for a configuration channel to become available. After DLs 1050, 1052, and 1054 are sent, the configuration channels are open, and WM 302 assigns configuration channel 2 to WH4306.4. WH4306.4 then sends DL 1058 to its WDs 308 in its sub-cluster 304. During the time that DL 1058 is transmitted, the other WHs 306 wait for DL 1058 to conclude. These waiting periods are shown as 1060A, 1060B, and 1060C for the first three WHs 306.
After the scan request DLs are sent to WDs 308, the WDs 308 respond to their respective WH 306 in the mini super frame. For this response, data channels are used rather than configuration channels, as they were in super frame 1002A. The data channels rotate for this super frame 1002B, just as the configuration channels rotated. WH1306.1 uses channel A2, WH2306.2 uses channel B2, WH3306.3 uses channel C2, and WH4306.4 uses channel D2. WH1306.1 receives ULs 1062 and 1064, WH2306.2 receives ULs 1066 and 1068, WH3306.3 receives ULs 1070 and 1072, and WH4306.4 receives ULs 1074 and 1076.
After the ULs have been received by the WHs 306 from the WDs 308, each WH 306 aggregates the responses from its WDs 308 and sends a UL to WM 302 on channel M2. WH1306.1 sends UL 1078, WH2306.2 sends UL 1080, WH3306.3 sends UL 1082, and WH4306.4 sends UL 1084. WM 302 receives ULs 1086A-1086D, and super frame 1002B concludes.
If any WH 306 completes forming its sub-cluster 304, the WH 306 continues sending DL frames in the allocated configuration channels and receiving UL frames in the appropriate hopping sequence. This process continues until all sub-clusters 304 are formed and WM 302 informs all the WHs 306 to switch to super frame Type 2. In some examples, Option 3 is more complex than Options 1 or 2 but also may be faster if there are a large number of sub-clusters 304.
Super frame structure 1100A in
In super frame structure 1100A, super frame 1102A operates similarly to super frame 1002A discussed above with respect to
WH1306.1 receives DL 1106A, WH2306.2 receives DL 1106B, WH3306.3 receives DL 1106C, and WH4306.4 receives DL 1106D. DL 1104 from WM 302 contains an indication that WH1306.1, WH2306.2, WH3306.3, and WH4306.4 are in the scanning or network formation phase. WM 302 assigns the selected configuration channels and data channels to WH1306.1, WH2306.2, WH3306.3, and WH4306.4.
Each WH 306 in the network formation phase transmits a scan request DL to each WD 308 in its respective sub-cluster 304 on its respective configuration channel. WH1306.1 sends DL 1108 on configuration channel 1, WH2306.2 sends DL 1110 on configuration channel 2, and WH3306.3 sends DL 1112 on configuration channel 3. WH4306.4 waits in a waiting period 1114 for a configuration channel to become available. After DLs 1108, 1110, and 1112 are sent, the configuration channels are open, and WM 302 assigns configuration channel 1 to WH4306.4. WH4306.4 then sends DL 1116 to its WDs 308 in its sub-cluster 304. During the time that DL 1116 is transmitted, the other WHs 306 wait for DL 1116 to conclude. These waiting periods are shown as 1118A, 1118B, and 1118C for the first three WHs 306.
After the scan request DLs are sent to WDs 308, the WDs 308 respond to their respective WH 306 in the mini super frame. For this response, data channels are used rather than configuration channels. WH1306.1 uses channel A1, WH2306.2 uses channel B1, WH3306.3 uses channel C1, and WH4306.4 uses channel D1. WH1306.1 receives ULs 1120 and 1122, WH2306.2 receives ULs 1124 and 1126, WH3306.3 receives ULs 1128 and 1130, and WH4306.4 receives ULs 1132 and 1134.
After the ULs have been received by the WHs 306 from the WDs 308, each WH 306 aggregates the responses from its WDs 308 and sends a UL to WM 302 on channel M1. WH1306.1 sends UL 1136, WH2306.2 sends UL 1138, WH3306.3 sends UL 1140, and WH4306.4 sends UL 1142. WM 302 receives ULs 1144A-1144D, and super frame 1002A concludes.
In this example, network formation is complete after super frame 1102A. The WHs 306 indicate to WM 302 that they have completed network formation with ULs 1136, 1138, 1140, and 1142. Therefore, after receiving ULs 1144A-1144D, WM 302 switches to super frame Type 2 for super frame 1102B. Super frame 1102B operates similarly to Type 2 structures described above, such as super frame structure 400A in
In super frame 1102B in
The WDs 308 respond to WHs 306 with ULs as shown here. WH1306.1 receives ULs 1158A-1158F from its WDs 308 on channel A2, WH2306.2 receives ULs 1160A-1160F from its WDs 308 on channel B2, WH3306.3 receives ULs 1162A-1162F from its WDs 308 on channel C2, and WH4306.4 receives ULs 1164A-1164F from its WDs 308 on channel D2.
Each WH 306 aggregates the responses from the WDs 308 and transmits an UL to WM 302 on channel M2. WH1306.1 sends UL 1166, WH2306.2 sends UL 1168, WH3306.3 sends UL 1170, and WH4306.4 sends UL 1172. WM 302 receives ULs 1174A-1174D, and super frame 1102B is concluded. Therefore,
In super frame 1202A in
Responsive to DL 1204, each WH 306 sends a DL to the WDs 308 in its respective sub-cluster 304. In this example, WH1306.1 transmits a DL 1208 (DL WH1) to WD2 through WD7308. DL 1208 is transmitted on channel A1. WH1306.1 uses channel A1 to communicate with its WDs 308 in first super frame 1202A. WH2306.2 transmits a DL 1210 (DL WH2) to WD9 through WD14308. DL 1210 is transmitted on channel B1. WH2306.2 uses channel B1 to communicate with its WDs 308 in first super frame 1202A. In this example, each sub-cluster 304 uses a different channel for communications between the WH 306 and the WDs 308 in the sub-cluster 304.
Each WD 308 receives the DL (1208 or 1210 in this example) from its respective WH 306. Only WD2308.2 and WD14308.14 are shown in
After receiving ULs from each WD 308 in its sub-cluster, each WH 306 aggregates the information in the ULs from the WDs 308 in its sub-cluster and sends an UL to WM 302. Here, WH1306.1 sends UL 1224 to WM 302 on channel M1. WH2306.2 sends UL 1226 to WM 302 on channel M1. ULs 1224 and 1226 are sent at different times on channel M1 as shown, so they do not interfere with one another. WM 302 receives ULs 1228A-1228D from each WH 306 that it manages. At this time, first super frame 1202A is complete and second super frame 1202B begins.
Super frame 1202B in
Examples herein may include procedures for a node rejoin process. If a specific WD 308 in a sub-cluster 304 stops communicating while in normal operation, after a timeout, the WH 306 can instruct the WDs 308 in the sub-cluster 304 to scan the configuration channels. The WH 306 informs WM 302 that the WH 306 is entering a pairing phase. The other WHs may continue normal operation. After all WDs 308 in the sub-cluster 304 respond to the WH 306, WH 306 informs WM 302 and WM 302 initiates the master hopping sequence for the WH 306. In a single-tier network, all nodes would be asked to scan configuration channels even if only one WD 308 lost the connection. Here, the other sub-clusters 304 may continue operation while another sub-cluster 304 performs a rejoin operation.
If a WH 306 stops communicating with a WM 302, the WM 302 may re-initiate the pairing process for all WHs 306. The WDs 308 would be asked to scan configuration channel to begin the re-initiation.
Method 1300 begins at 1310, where a wireless head node (WH 306) receives, in a super frame, a first downlink on a first channel from a wireless master node (WM 302) in a WBMS, where the wireless head node is a head node for a sub-cluster 304 of one or more wireless devices 308. One examples of a first downlink is DL 406A in super frame 402A in
Method 1300 continues at 1320, where the wireless head node (WH 306) transmits, in the super frame, a second downlink on a second channel to each of the one or more wireless devices 308 in the sub-cluster 304. The second downlink may be DL 408 in
Method 1300 continues at 1330, where the wireless head node (WH 306) receives, in the super frame, an uplink from each of the one or more wireless devices 308 on the second channel. In one example, the uplinks from the wireless devices 308 are ULs 420A-420F in
Method 1300 continues at 1340, where the wireless head node (WH 306) transmits, in the super frame, an aggregated uplink from the wireless head node (WH 306) to the wireless master node (WM 302) on the first channel, where the aggregated uplink includes data from each of the one or more wireless devices in the sub-cluster. In one example, the aggregated uplink is UL 424 in
In examples herein, a hierarchical WBMS network structure is described that can handle a large number of nodes with low latency and one-hop extension. A primary node (WM 302) operates as a master node for an entire network of nodes. The secondary nodes are divided into sub-clusters 304, with one or more secondary nodes in each sub-cluster 304. A secondary node in each sub-cluster operates as a wireless head (WH 306) node, and acts as a master node for the sub-cluster 304 to which it belongs. The other secondary nodes in each sub-cluster 304 are WDs 308. In some examples, a dedicated WH 306 node may be used in the sub-cluster 304 rather than selecting one of the WDs 308 as the WH 306. The WM 302 and the WHs 306 can use a master hopping sequence to manage the communications channels used by the nodes.
In the hierarchical system described herein, WM 302 communicates with the WHs 306, and the WHs 306 communicate with the WDs 308. WM 302 is in communication range with the WHs 306, and the WHs 306 are in communication range with their respective WDs 308 in their sub-cluster 304. The sub-clusters 304 may have the same number of WDs 308 or a different number of WDs 308. A number of super frame structures are described herein for managing communications between nodes arranged in the hierarchical system.
For a WBMS with a large number of nodes, latency is reduced with the hierarchical system and super frame structures described herein. Throughput is also increased due to the efficient super frame structures. Low network restart times may be achieved, and power consumption may also be reduced in the examples herein.
In this description, the term “couple” may cover connections, communications, or signal paths that enable a functional relationship consistent with this description. For example, if device A generates a signal to control device B to perform an action: (a) in a first example, device A is coupled to device B by direct connection; or (b) in a second example, device A is coupled to device B through intervening component C if intervening component C does not alter the functional relationship between device A and device B, such that device B is controlled by device A via the control signal generated by device A.
A device that is “configured to” perform a task or function may be configured (e.g., programmed and/or hardwired) at a time of manufacturing by a manufacturer to perform the function and/or may be configurable (or reconfigurable) by a user after manufacturing to perform the function and/or other additional or alternative functions. The configuring may be through firmware and/or software programming of the device, through a construction and/or layout of hardware components and interconnections of the device, or a combination thereof.
In this description, unless otherwise stated, “about,” “approximately” or “substantially” preceding a parameter means being within +/−10 percent of that parameter. Modifications are possible in the described examples, and other examples are possible within the scope of the claims.
