Battery-operated gateway for obtaining geographic location of short-range beacons over a low-power wide-area network - Patents.com

Abstract

The battery powered gateway demodulates signals from whitelisted short-range beacons and processes and stores the data in memory. Periodically, the collected data is transmitted in an LPWAN frame along with the gateway's geographic location. The battery powered gateway can be used for multiple years without the need to replace the battery and may be used to enable the deployment of a low-cost infrastructure to connect short-range beacons to any cloud application. Typical application areas include (but are not limited to) asset inventory management, asset tracking, or sub-metering.

Description

[Technical field]

[0001] The present invention relates to the Internet of Things, and more particularly to a method for connecting Short-Range Devices to a Low-Power Wide-Area Network while implementing a power saving mechanism that utilizes a deep sleep method. [Background technology]

[0002] The Internet of Things ("IoT") is a type of communication network in which multiple sensors communicate with a backend infrastructure to optimize the efficiency of, for example, city or business operations. Internet of Things applications may rely on a class of wireless systems under the general name of low-power wide area networks ("LPWANs"), which operate under regulations for short-range devices ("SRDs") and are particularly suited for devices that only need to transmit a few bytes of messages per day. The LPWAN technologies may be proprietary or may be open standards and are designed to accommodate large-scale IoT applications with a very large number of connected devices. One of the most common use cases is tracking unpowered assets in logistics, retail, manufacturing, smart cities, and agriculture.

[0003] LPWANs use a star topology architecture in which multiple access points ("APs") are placed between multiple devices and the communication network, and these access points ("APs") can backhaul the data to the LPWAN core network using multiple different communication technologies (such as 3G, 4G, Ethernet, Wi-Fi, etc.). When installed at high altitudes and outdoors, LPWAN APs can cover up to tens of kilometers with thousands of devices within the coverage area of ​​the BS. For deep indoor applications such as gas or water metering, repeaters may be installed to extend the LPWAN coverage inside the building. Since LPWAN systems typically use license-exempt spectrum, mechanisms to ensure fair use of frequency resources are realized by duty cycle (1% or 10%), "listen-before-talk", or "frequency hopping" mechanisms. Devices, access points, and repeaters must respect restrictions and can therefore only meet low throughput requirements. Some examples of LPWANs popular in the world today are Sigfox and LoRaWAN.

[0004] Sigfox relies on ultra-narrowband ("UNB") technology, which combines high selectivity filtering and narrower signal bandwidth (100 Hz) to improve the susceptibility threshold. Two modulation formats are available, 100 bps and 600 bps, and each uplink frame with a maximum 12-byte payload can be repeated up to three times in multiple different frequency channels to improve message success rates. For example, using a standard configuration (e.g., 3 frames per message, 100 bps, each device with a 1% duty cycle), it is possible to transmit up to 72 bytes per hour, and using a high-capacity configuration (e.g., no repetition, 600 bps), it is possible to transmit 1296 bytes per hour, which is 18 times the standard configuration.

[0005] LoRaWAN uses the chirp spread spectrum technique ("CSS"), which reduces the susceptibility level below the noise threshold thanks to a coding gain that depends on the spreading factor. For a bandwidth of 125 kHz, using a spreading factor of 12 a device can transmit up to 438 bytes per hour at the application layer, whereas a spreading factor of 7 increases the amount of data that can be transmitted to 14455 bytes per hour.

[0006] Apart from low throughput networks, SRD ECC Rec. 70-03 also encapsulates different usage patterns including wideband data ("WB") transmissions provided by standards such as Bluetooth, RFID, NFC, Wi-Fi, or UWB. Both LPWAN and WB devices use very low power, similar to LPWAN devices, but LPWAN is optimized for long-range low-throughput communication (a few bytes over tens of kilometers), whereas WB is designed for short-range high-throughput communication (a few kilometers / megabytes over a few meters) using license-exempt spectrum. WB wireless networks consist of multiple access points that connect devices to the WB core network using a supporting communication technology (Ethernet, xPON, 4G, etc.). WB AP coverage ranges from 20 to 50 m indoors.

[0007] Short-range beacons ("SRBs") are a subclass of WB SRDs that broadcast advertisement frames ("ADVs") containing one or more unique identifiers ("UIDs") at regular intervals. The UID and a few bytes transmitted with it may be used to determine the physical location of the SRB, track customers, or trigger location-based actions for the device, such as social media check-ins or push notifications. However, it is important to note that SRBs are small, consisting of only a few electronic chips, and powered by a small coin battery. GNSS modules (or equivalent high-precision geopositioning modules), which require significant amounts of energy in addition to being costly, are not commonly found in SRBs. As a result, SRBs cannot broadcast their absolute location, and positioning of SRBs can only be achieved by indirect methods, a new method being the subject of this patent application. SRBs are not attached, paired, or controlled by a network infrastructure during normal operation. The most common SRBs on the market today rely on the Bluetooth Low Energy ("BLE") standard.

[0008] BLE is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group ("Bluetooth SIG") for new applications in healthcare, fitness, beacon, security, and home entertainment industries. Compared to classic Bluetooth, Bluetooth Low Energy significantly reduces power consumption and cost while maintaining a comparable communication range. Supported by the majority of operating systems for smartphones and computers, BLE has gained a lot of momentum not only for consumer applications but also in the industry. A Bluetooth beacon is a hardware transmitter, a type of Bluetooth low energy and SRB device, that broadcasts an identifier to nearby portable electronic devices. The format of a BLE beacon follows various standards such as iBeacon or Eddystone UID defined by industry leaders.

[0009] The communication protocols that SRB uses are low-power communication protocols that allow devices to be manufactured small in size while being designed to last for years. Also, as the market has adopted these technologies on a large scale, the price of electronic components has dropped significantly over the years. Handheld cellular devices that support these protocols have also increased dramatically over the years. For these reasons, small SRB tags have become very popular in the IoT domain, especially for automatic inventory applications and asset tracking applications. To be able to function properly, IoT applications that use SRB rely on a dense infrastructure of gateways, usually one every 10 meters (the maximum range of SRB), connected to a power outlet, and using Wi-Fi, cellular, or wired lines to backhaul information to the Internet.

[0010] A battery-powered gateway ("BGW") is an electronic device that relays information between multiple electronic devices and a communication core network, where the power source for the electronic devices consists of a battery (primary or rechargeable). The BGW typically acts as a transparent node in the end-to-end communication, receiving, processing, and transmitting data with minimal information loss. The BGW can implement network operation methods to control the information flow and optimize the efficiency of resource utilization. The BGW can also embed additional operation and maintenance functions, such as geographic location, and periodically report its location to the network.

[0011] Battery-powered gateways for short-range beacons ("SRB BGWs") exist on the market, but these battery-powered gateways do not rely on LPWANs to backhaul data to the Internet and do not offer multi-year lifespans without battery replacement. This is primarily due to the high-throughput, low-latency nature of the SRD protocol, which requires the gateway to constantly transmit and receive data without the option to enter deep sleep modes to conserve battery. Also, most SRB BGWs can be paired with an SRB for features such as firmware upgrade over the air ("FOTA"), requiring both the SRB and the SRB BGW to communicate for extended periods of time.

[0012] In the case of a mesh network, each relay node may be considered an SRB BGW, but does not backhaul information over the LPWAN and therefore provides only short-range connectivity. Connectivity to the core network is ensured via sink / source nodes connected to the Internet.

[0013] The object of this application is to disclose a battery-operated gateway for the geolocation of SRBs over LPWAN, which overcomes the drawbacks of existing solutions by collecting a large amount of input data (or ADV) from a short-range network such as BLE and then transmitting such a large amount of data in a single message over a long-range LPWAN such as Sigfox. A further object of this application is to disclose a deep sleep strategy for such a gateway, which is performed between the collection of short-range network inputs and the transmission of output data over the LPWAN, to reduce the energy consumption to enable the gateway as a wireless device. A further object of this application is to disclose an algorithm that allows data from multiple SRDs collected in a short-range network format to be aggregated into a single LPWAN format message and save on throughput.

[0014] This application aims to demonstrate how such a system can operate in a real-time inventory control and asset tracking industrial context without the need to have a single device connected to a power outlet or to rely on a public cellular or wired communication network, in contrast to other solutions and devices in the field of inventory control and asset tracking that rely on such power sources and / or communication networks. Summary of the Invention

[0015] The BGW retrieves, processes and transmits the information contained in the ADV of the fleet of SRBs located in the vicinity of the gateway over the LPWAN. The transmission of the SRB ADV is uplink only and is timed by the timer T ADV Or triggered by an external event.

[0016] A common ADV format for SRB is - The header [10.1] is a few bytes that describe the payload size and type, and also contains a physical layer preamble. - The unique identifier (UID) [10.2] is typically a medium access control ("MAC - 6 bytes"), consisting of an organizationally unique identifier ("OUI - 3 bytes") and a network interface specific ("NIC - 3 bytes"). - The data is typically several tens of bytes and has an identifier Block i ID [10.3] and Data Block i Data It consists of two additional blocks of information [10.4]: the data blocks may contain, for example, temperature or battery level, while the identifier blocks may be organised hierarchically. - CRC[10.5] is a Cyclic Redundancy Check (physical layer). , may be written as follows.

[0017] From a high-level perspective, the BGW executes three sets of routines at regular intervals or when triggered by sensing events. The first routine, named "data acquisition" ("DAC"), is intended to acquire and store SRB ADV data, while the second routine, named "data transmission" ("DTR"), is intended to send aggregated ADV data from the first routine to the cloud or LPWAN technology backend (e.g., Sigfox or other platform) via the LPWAN. The first routine is usually executed multiple times before the second routine. A third routine, named "geolocation" ("GEO"), aims to acquire the geographical location of the BGW by using GPS, Wi-Fi, and / or BLE data sniffing, or message reception to network cloud post treatment methods (e.g., triangulation, machine learning, etc.). These post calculations are outside the scope of this patent, and will not be described below, since DAC and DTR remain the same, and DAC and DTR are value-added services provided by the LPWAN cloud owner.

[0018] (Timer T DAC or triggered by an external sensing event. - wake up from deep sleep mode, - Duration W DAC demodulation of the SRB ADV during a data sniffing window having - measuring the Received Signal Strength Indicator (RSSI) of each SRB ADV; - Filtering of ADV data based on user-defined criteria of header, UID, data block, or RSSI; - storing the filtered ADV data in a memory register; - fall back into deep sleep mode, It is.

[0019] For each beacon being demodulated, the BGW stores in a memory register at least the SRB UID, content payload, RSSI, and timestamp. To filter eligible SRBs that can connect to the BGW, it may implement whitelisting on SRB UID ranges, for example against organizationally unique identifiers (OUIs), to demodulate only SRBs from a particular manufacturer. customer ID and project identifier Block project ID If the BGW configuration is organized as a single line, it would be possible to filter only certain customers or projects. The filtering options and codes can be configured by downlink over the LPWAN, allowing over the air update of the BGW configuration.

[0020] The demodulation or sniffing window, the duration of the DAC routine, depends on the configuration of the ADV beacon in the SRB, and it is recommended that the sniffing interval be N times the average ADV interval.

[0021] Aggregating Data

[0022] The implementation of the DAC routine is described in the context of Bluetooth Low Energy (BLE) for short-range protocols and Sigfox as an LPWAN. The DAC routine aggregates and compresses the ADV of the SRB. Assuming that the SRB is a BLE beacon using the iBeacon format, the frame size is 31 bytes with a UUID (which is 16 bytes) and major and minor IDs (each of which is 2 bytes). The SRB BGW demodulates all of the SRB frames, but discards the SRB frames that do not fully or partially match the UUID configured in the SRB BGW. Furthermore, the SRB BGW may also discard BLE frames with low RSSI, since these are likely to be emitted from SRBs that are far away. For whitelisted frames, only the major ID (which is 2 bytes) will be kept in memory and then transmitted during the DTR routine. Since a Sigfox uplink frame has a payload of 12 bytes, the compression ratio of the DAC in the presented configuration is 92.3%.

[0023] If more SRBs need to be whitelisted, then the minor ID may also be used.

[0024] (Timer T DTR or an external sensing event triggered) data transmission (DTR) routine, - Wake up from deep sleep mode, - rank the memory entries according to configurable criteria (most number of occurrences, maximum RSSI, oldest timestamp, etc.), - Creation of an LPWAN frame payload by concatenating data from the highest priority memory entries, possibly applying compression techniques such as sending only a portion of the UID or only a specific block of information; - Transmission of LPWAN frames until successful when information is available; - Deletion of transmission entries sent from memory registers, It is.

[0025] The geolocation (GEO) routine (triggered by the end of the DTR) - Assign a priority to each geolocation acquisition method (e.g., (1) Wi-Fi, (2) BLE, (3) GPS, ordered from least energy consuming acquisition method to most energy consuming acquisition method) depending on the configuration implemented by the user or hardware manufacturer. - Obtain geographic location information starting with the geographic location method with the highest priority. If geolocation information is obtained successfully, it transmits it over the LPWAN and then returns to deep sleep mode. If the geographic location information is not successfully acquired, the geographic location acquisition method with the next highest priority is used to acquire the geographic location. - Recover from deep sleep mode, It is.

[0026] The DAC and DTR routines are triggered by timers or external events (such as motion detection or presence detection). Since the frequency bands used by LPWANs are generally ISM bands, the timers of the DTR routines need to be set to comply with local regulations (such as duty cycle or listen-before-talk) regarding media access control. In Europe, the timers for DAC and DTR may be set to, for example, 10 minutes and 60 minutes, respectively. The SRB ADV interval is selected to be significantly small to meet industry standards for connecting to a handheld device (as the primary connection for the SRB) and to save energy for the BGW, allowing the data interception period of the BGW to be relatively short. [Table 1]

[0027] The BGW uses the downlink frame to - beacon whitelist parameters, - Data sniffing window W DAC and the duration of the beacon demodulation period T DAC , - Behavior of low-power wide-area network transmissions DTR , - geolocation parameters and priority preferences, may be configured to update

[0028] The lifetime of the BGW increases with the duration of the deep sleep mode, where the power consumption is the lowest. Also, the DAC, DTR and GEO parameters have a large impact and it is recommended to tune the parameters for the use case. Several parameters need to be considered, but the environment (indoor or outdoor), the speed of movement and the density of SRBs are the most important. If the SRBs and BGWs are located indoors, it is recommended to avoid using GNSS methods in the GEO routine, as the success rate may be low and the energy consumption may be high. In this case, low energy methods such as "Wi-Fi data sniffing" or "BLE data sniffing" are recommended. The acquisition interval of the BGW beacons T DAC quantifies the ability of a BGW to detect the presence of an SRB in its vicinity (approximately 20 m). For example, for an SRB that moves slowly because it is attached to furniture in an office space and for a BGW that is fixed to a wall, the value T DAC Increasing the data transmission interval T is unlikely to affect the system's detection capabilities, but will save battery power. DTR This affects the throughput of the BGW and the accuracy of geographical location acquisition. When the density of SRBs near the BGW is high, the T DTR Since LPWANs generally use unlicensed spectrum, it is recommended to reduce T DTR The value of would, for example, be limited to 10 minutes in Europe for the 868 MHz ISM band.

[0029] To increase the system throughput and increase the system's ability to relay more information from the SRB to the LPWAN while complying with regulations, various strategies can be implemented. In the case of Sigfox, a higher modulation scheme may be used and frame repetition may not be used, while a lower spreading factor provides greater throughput in LoRaWAN. Both of these strategies result in a reduction of the maximum transmission range by lowering the available link budget.

[0030] BGW throughput

[0031] The throughput of the BGW is defined as the uplink throughput between the BGW and the LPWAN. As described in the DAC and DRT routines, the advertisement frame ("ADV") of the SRB is processed and compressed by the BGW to a size S SRB Each SRB is transmitted as a block of 1000 Mbps, with each SRB being assigned the same number of bytes. Expressing the throughput of the BGW in blocks per day is therefore convenient to reflect the number of SRBs that can be bridged to the LPWAN. The results are shown in Tables 2 and 3. [Table 2] [Table 3]

[0032] Using the typical values ​​in Table 1, the throughput of the BGW is 120 SRB blocks per day at 100 bps modulation.

[0033] Battery life

[0034] The battery life of the BGW depends on many factors and ranges from 6 months to 15 years for the range of values ​​discussed in Table 4. The following battery monitoring and operations are available: - The BGW battery level [20.3] is transmitted periodically as in-band signaling to the LPWAN to facilitate monitoring of its battery. - Configuration parameters may be updated by downlink LPWAN messages to optimize battery consumption. - The BGW is designed so that the battery can be replaced. [Table 4]

[0035] The DAC and DTR routines may also be executed based on sensing events such as detected motion. The DTR routine must follow frequency band regulation (e.g. every 20 minutes), but there is no regulation for the DAC routine, and therefore the battery life cannot be predicted. To maximize the life of the BGW, it is recommended in any case to implement a data acquisition interval to avoid quick drainage of the battery. Such a policy could be, for example, "execute the DAC routine every 10 minutes while motion is detected, and every hour otherwise". Potential sensing events could be acceleration (and / or orientation also given by the same sensor, i.e. the accelerometer), motion detection, light detection, temperature threshold or deviation, pressure (altitude change).

[0036] Deep Sleep Strategy

[0037] LPWAN protocols such as Sigfox and LoRaWAN allow the SRB BGW to enter deep sleep whenever it is not transmitting or sensing data.

[0038] Using the typical values ​​in Table A, over the course of an hour: - 6 DAC events of 5 seconds each, - 1 DTR event of 2 seconds duration (assuming a 12 byte Sigfox transmission according to European regulations), and - one GEO event with an average duration of 15 seconds (under the assumptions in Table D), There will be

[0039] As a result, the SRB BGW will be active only 1.31% of the time and the overall system will be in deep sleep mode for the rest of the time. The deep sleep period may be further extended using the SRB BGW's sensing module [2.6]. To save energy, it is recommended to lower the sampling frequency of the sensing module (e.g., every minute). Depending on whether the SRB BGW is fixed or mobile, two possible strategies can be implemented:

[0040] Fixed SRB BGW with presence detection sensor

[0041] The SRB BGW will be mounted in a fixed location (ceiling, wall, etc.) and will typically be used to take inventory of assets within beacon range equipped with an SRB. When the passive infrared ("PIR") sensor does not detect any presence, the SRB BGW will remain in deep sleep since the asset inventory is likely to remain stable (assuming the range of the PIR and SRB are similar). Each time a PIR is triggered, the SRB BGW will perform at least one DAC / DTR cycle. GEO cycles may only be performed on a daily or weekly routine as part of a keep-alive procedure.

[0042] Movable SRB BGW with acceleration detection sensor

[0043] The SRB BGW would be mounted, for example, on a truck and the SRB beacons would be mounted on assets transported by the truck, such as returnable shipping items (RTI-plastic boxes, roller cages, etc.). In this case, the use of the SRB BGW could potentially know which RTIs are being transported by the truck. Whenever the truck is moving, the asset inventory remains steady and the SRB BGW executes DAC / DTR / GEO routines. Whenever the truck remains stationary for a significant duration (e.g., 5 minutes), the SRB BGW goes into deep sleep mode. [Brief description of the drawings]

[0044] [Figure 1] 1 is a system overview illustrating the present invention, in which a battery-operated gateway relays information from short-range beacons towards a low-power wide-area network. [Diagram 2] The block diagram of a battery-powered gateway [2] is shown. [Diagram 3] Figure 1 shows the state machine diagram of a battery-powered gateway [2]. [Figure 3a] 1 shows the state machine diagram of a battery-powered gateway [2] configured for periodic transmission of DTR. [Figure 3b] Figure 2 shows the state machine diagram of a battery-powered gateway [2] with a presence detector acting as a sensing module [2.6]. [Figure 3c] This shows the state machine diagram of a battery-powered gateway [2] with an accelerometer acting as a sensing module [2.6]. [Figure 4] This explains the ADV frame format transmitted by the SRB [1] and the DTR transmitted by the BGW [2]. [Diagram 5] The timeline of events for SRB[1] and BGW[2] (such as periodic transmissions) is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The BGW may be implemented with reference to Table 5. [Table 5]

[0046] Industrial application fields

[0047] The present invention aims to facilitate the deployment of a low-cost and battery-powered network infrastructure for arbitrary connection of short-range beacons to cloud applications. The following use cases may be applied:

[0048] Asset Inventory Management In office space management, the SRB as a small footprint device may be attached to virtually any asset, such as furniture. Installing a BGW in an office will allow for automated inventory management of furniture in a given area, without the need to manually count or scan each piece of furniture at regular intervals.

[0049] Asset Tracking In logistics, returnable industrial packaging plays an important role in making the economy more circular by replacing one-off packaging. SRBs can be attached to plastic pallets, for example, and BGWs installed on transport trucks and in docking areas allow visibility into the movement of those plastic pallets.

[0050] Submetering: In practical terms, the BWG may be used to aggregate data from multiple devices, rather than the devices sending the information directly to the cloud. For example, consumption measurements and warnings of individual meters may be transmitted without equipping each meter with a long-distance metering sensor. The BWG is therefore used as a hub that contains most of the high-value components and most of the necessary energy consumption, and is still (more) accessible compared to meters (e.g. deep underground meters). This communication reduces the consumption of individual meters and their costs (compared to communication that integrates LRWAN in addition to the current definition). It also increases the number of compatible meters on the market and possibly their coverage in the area.

Claims

1. 1. A battery operated gateway for obtaining geographical location of short range beacons over a low power wide area network, the gateway comprising: a short-range beacon receiving module capable of receiving and demodulating on the uplink a plurality of SRB ADVs from each SRB in the vicinity of the gateway during a data interception window occurring at periodic intervals on a user-defined frequency transmitted over a short-range wireless network; [2.1] and A control module [2.2], comprising: - filtering the SRB ADV data based on user-defined criteria such as header, UID, data block, and RSSI; - compressing the filtered SRB ADV so as to be able to transmit the filtered SRB ADV in a single LPWAN frame; - storing the filtered SRB ADV in a memory module [2.3]; - ranking the filtered SRB ADVs based on user-defined priority criteria such as maximum number of occurrences, maximum RSSI, oldest timestamp, etc., and creating an LPWAN frame from the highest priority; - a process for receiving data from a geographic location acquisition module [2.7]; A control module [2.2] that measures the RSSI of each SRB ADV by executing a memory module [2.3] capable of storing demodulated SRB ADV data, network authentication information, and firmware; A low-power wide area network module [2.4] capable of transmitting and receiving long-range LPWAN frames (e.g. Sigfox networks, LoRaWan, etc.); a geographic location acquisition module [2.7] capable of determining the geographic location of its short-range beacons using GNSS or collecting supporting geographic location information, such as Wi-Fi addresses, based on said user-defined priorities, and transmitting said supporting geographic location information over a low-power wide area network; a power source [2.5] in the form of a long-lasting battery that is designed to last for years without needing replacement by utilizing a deep sleep method triggered by the sensing module [2.6]; A sensing module [2.6] capable of measuring physical quantities such as acceleration detection or presence detection, said sensing module [2.6] being used to trigger the processes of said short-range beacon receiving module [2.1] and said control module [2.2], to vary the frequency of said processes and to trigger deep sleep states between said processes based on inputs measured by said sensing module [2.6]; Including, gateway.

2. 10. The gateway of claim 1, further comprising an SRB receiving module capable of creating a whitelist based on an SRB UID range to filter which SRBs are allowed to connect to said battery powered gateway.

3. 2. The gateway of claim 1, further comprising a short-range beacon receiving module [2.1], a control module [2.2], a geographical location acquisition module [2.7], a low-power wide area network module [2.4] and a long-range configuration of a sensing module [2.6], which are capable of modifying the parameters of the data interception window, the duration of the demodulation period and the frequency based on the input from the sensing module [2.6], the behavior of the low-power wide area network transmissions and the geographical location acquisition and priority.

4. The gateway according to claim 2, further comprising a short-range beacon receiving module [2.1] and a long-range configuration of a control module [2.2] via the low-power wide area network, which allows modifying the creation of the whitelist of short-range beacons.

5. 10. The gateway of claim 1, further comprising a power source in the form of a rechargeable battery.

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