Long-range communication availability in elevator shaft

Abstract

The present invention relates to a method, a telemetry unit and a computer program product for determining long-range connectivity of a telemetry unit associated with an elevator car. A plurality of network echoing utility messages are sent over a long-range wireless communication network towards at least one known server at each of a plurality of positions within the elevator shaft, and one or more network echoing utility reply messages are received in response. A connectivity value at each of said plurality of positions is determined based at least on number of network echoing utility reply messages received from the at least one known server in response to said sending the plurality of network echoing utility messages at the respective position.

Description

[0001] Long-range communication availability in elevator shaft

[0002] Field

[0003] The present invention relates to a method, a system and a computer program product related to telemetry within an elevator shaft. More particularly, the present invention relates to a method, a system and a computer program product related to determining long-range communication availability at different positions within the elevator shaft.

[0004] Background

[0005] Elevator systems may need to communicate with other devices or systems in a wireless manner. Long-range connectivity in a building, especially in an elevator shaft, is often poor, and typically depends on position within the elevator shaft. Long-range connectivity may depend on communication technology used. For example, different technologies have been allocated with different wavelengths, which affects the behavior of the wireless radio signal. Communication network operators, such as cellular network operators, have a lot of control over communication traffic in their network. For example, operators may determine different priorities to different types of wireless communication devices, and a wireless communication device with low priority may suffer from poor connectivity if nearby devices with higher priority consume available communication resources.

[0006] The elevator system may comprise or be associated with a variety of sensors and other devices for monitoring the operation of the elevator. Such data can be referred to as telemetry data. In elevator field, telemetry refers to automatic collection of data from various elevator- related data sources and telemetry messages refer to communication used for transmitting the collected telemetry data to a central location, referred herein as a telemetry server, where data is analyzed to monitor and control the elevator system, or even multiple elevator systems. To enable continuous monitoring and / or control of the elevator system, telemetry data is preferably sent as telemetry messages over the long-range communication connection to the telemetry server for processing the data. The operation of the elevator may also be remotely controlled based on the telemetry data. For example, if a failure of any critical component is detected, the elevator may be remotely disabled until fixed by maintenance personnel. An emergency may be detected based on the telemetry data and operation of the elevator may be remotely controlled accordingly.

[0007] Telemetry messages are typically delivered using a best effort approach, referred to with an abbreviation QoS 0, and also referred to as "at most once". According to this principle, each telemetry message is thus sent only once, and there is no guarantee of delivery, no acknowledgement or reception, nor retransmission.

[0008] Ping, also known as ICMP Echo Request, is a computer network administration software utility used to test the reachability of a host on an Internet Protocol (IP) network using Internet Control Message Protocol (ICMP) packets. It is available for virtually all operating systems that have networking capability. Ping measures the round-trip time for messages sent from the originating host to a destination computer that are echoed back to the source. Ping, like ping6 providing corresponding functionality in IPv6 are examples of applications that are particularly designed to send data packets and monitor return rate and latency.

[0009] Daytime Protocol and Time Protocol are examples of well-known internet protocols for providing site-independent time over TCP or UDP. Both protocols comprise sending a request to a server that returns the current date and time. The format of the returned data depends on the protocol.

[0010] Description of the related art

[0011] Patent EP3575256 discloses using network signal strength measured at a conveyance system, such as an elevator, to determine availability of long-range network connectivity between a controller that transmits sensor information of the conveyance system to a remote system.

[0012] Summary

[0013] An object is to provide a method and apparatus so as to solve the problem of knowing when the telemetry unit, in particular the at least one long-range wireless communication device thereof is in a position within an elevator shaft that has good long-range connectivity. Objects of the present invention are achieved with a method according to claim 1. The objects of the present invention are further achieved with an apparatus according to the characterizing portion of claim 11, and a computer program product according to claim 21.

[0014] The preferred embodiments of the invention are disclosed in the dependent claims.

[0015] The present invention is based on the idea of utilizing a network echoing utility for determining reachability of at least one host at different longitudinal positions within the elevator shaft.

[0016] According to a first aspect, a method for determining long-range connectivity of a telemetry unit associated with an elevator car is provided. The method comprises sending, via at least one long-range wireless communication device of the telemetry unit, a plurality of network echoing utility messages over a long- range wireless communication network towards at least one known server at each of a plurality of positions within the elevator shaft, and receiving, via the at least one communication device, one or more network echoing utility reply messages in response to sending said plurality of network echoing utility messages. The method further comprises determining, by the telemetry unit, a connectivity value at each of said plurality of positions based at least on number of network echoing utility reply messages received from the at least one known server in response to said sending the plurality of network echoing utility messages at the respective position. The long-range wireless communication device is referred herein in short as the communication device.

[0017] According to some embodiments, the connectivity value is determined at least at the plurality of positions associated with landing levels of an elevator car configured to travel between said landing levels in longitudinal dimension of an elevator shaft.

[0018] According to some embodiments, the connectivity value is calculated as at least one ratio calculated between received network echoing utility reply messages and the plurality of network echoing utility messages sent at the respective position.

[0019] According to some embodiments, the method further comprises determining the connectivity value or an auxiliary connectivity value based on round trip times of network echoing utility messages and respective network echoing utility replies.

[0020] According to some embodiments, the method further comprises repeating said sending the plurality of network echoing utility messages and said determining the connectivity value at a plurality of different times of day and / or different weekdays.

[0021] According to some embodiments, the method further comprises determining a plurality of connectivity values for at least one of: a plurality of long-range communication technologies, such as any of 3G, 4G, 5G and / or 6G telecommunication network, Long Range Wide Area Network (LoRaWan), narrowband-internet of Things (NB-IoT), Low Power Wide Area (LPWA) technology and satellite communications, a plurality of different network operators, a plurality of different base stations of the long-range communication network.

[0022] According to some embodiments, the method further comprises generating a connectivity map comprising the plurality of connectivity values determined at each of the plurality of positions. According to some embodiments, the connectivity map further comprising connectivity values at a plurality of different times of day and / or different weekdays.

[0023] According to some embodiments, the method further comprises delaying or buffering sending of telemetry messages until the at least one communication device is at a position at which the connectivity value exceeds a threshold.

[0024] According to some embodiments, the method further comprises selecting the long-range wireless communication technology, network operator and / or base station to be used for sending telemetry messages based on the plurality of connectivity values.

[0025] According to some embodiments, the method comprises sending a plurality of copies of the telemetry message if the telemetry message is sent at a position at which the connectivity value is below a threshold.

[0026] According to a second aspect, a telemetry unit associated with an elevator car and configured to determine long-range connectivity is provided. The telemetry unit comprises at least one long-range wireless communication device (communication device) configured to send, a plurality of network echoing utility messages over a long-range wireless communication network towards at least one known server at each of a plurality of positions within the elevator shaft, and to receive one or more network echoing utility reply messages in response to sending said plurality of network echoing utility messages. The telemetry unit comprises at least one processor configured to determine a connectivity value at each of said plurality of positions based at least on number of network echoing utility reply messages received from the at least one known server in response to said sending the plurality of network echoing utility messages at the respective position. According to some embodiments, the at least one processor is configured to determine the connectivity value at least at the plurality of positions associated with landing levels of an elevator car configured to travel between said landing levels in longitudinal dimension of an elevator shaft.

[0027] According to some embodiments, the at least one processor is configured to calculate the connectivity value as at least one ratio calculated between received network echoing utility reply messages and the plurality of network echoing utility messages sent at the respective position.

[0028] According to some embodiments, the at least one processor is configured to determine the connectivity value or an auxiliary connectivity value based on round trip times of network echoing utility messages and respective network echoing utility replies.

[0029] According to some embodiments, the at least one communication device is configured to repeatedly send the plurality of network echoing utility messages and the at least one processor is configured to repeatedly determine the connectivity value at a plurality of different times of day and / or different weekdays.

[0030] According to some embodiments, the at least one processor is configured to determine a plurality of connectivity values for at least one of: a plurality of long- range communication technologies, such as any of 3G, 4G, 5G and / or 6G telecommunication network, Long Range Wide Area Network (LoRaWan), narrowband-internet of Things (NB-IoT), Low Power Wide Area (LPWA) technology and satellite communications, a plurality of different network operators, a plurality of different base stations of the long-range communication network.

[0031] According to some embodiments, the at least one processor is configured to generate a connectivity map comprising the plurality of connectivity values determined at each of the plurality of positions. According to some embodiments, the connectivity map further comprises connectivity values at a plurality of different times of day and / or different weekdays.

[0032] According to some embodiments, the at least one processor and / or the at least one communication device is configured to delay or buffer sending of telemetry messages, until at least one of the at least one communication device is at a position at which the connectivity value exceeds a threshold.

[0033] According to some embodiments, the at least one communication device is configured to select the long-range wireless communication technology, network operator and / or base station to be used for sending telemetry messages based on the plurality of connectivity values.

[0034] According to some embodiments, the at least one communication device is configured to send a plurality of copies of the telemetry message if the telemetry message is sent at a position at which the connectivity value is below a threshold.

[0035] According to a third aspect, a computer program product comprising computer executable code is provided. The computer executable code is configured, when executed by at least one processor of a telemetry unit of an elevator, to cause the telemetry unit to perform the method according to any of the above aspects and embodiments.

[0036] The present invention has the advantage that it decreases the amount of lost telemetry messages sent by a telemetry unit that uses long-range wireless communication and thus increases reliability of the communication between the elevator site and cloud services, and is located within the elevator shaft, typically in or on the elevator car. Preferably, a network echoing utility is used that applies an upper-level network protocol, such as any version of the internet protocol (IP), such as IPv4 or IPv6, the Internet Control Message Protocol (ICMP), to name a few, to indicate availability of the long-range connectivity taking into account a stack of communication protocols from physical layer up to the respective protocol level. Although telemetry typically applies best effort principles, resending of telemetry messages may be allowed for improving possibility for successful communication of telemetry messages that need to be sent at a position in which long-range connectivity is poor. This improves safety in exceptional and / or hazard situations of elevator operation.

[0037] Brief description of the drawings

[0038] In the following the invention will be described in greater detail, in connection with preferred embodiments, with reference to the attached drawings, in which:

[0039] Figure 1 illustrates a telemetry arrangement in an elevator system;

[0040] Figure 2 illustrates an exemplary telemetry data collection system of an elevator;

[0041] Figure 3 illustrates a method of determining long-range connectivity of a long- range communication device of a telemetry unit;

[0042] Figure 4 illustrates a method a method of determining long-range connectivity of a long-range communication device of a telemetry unit; and

[0043] Figure 5 illustrates a method of utilizing connectivity data for controlling the sending of telemetry messages.

[0044] Detailed description

[0045] In this context, the term long-range connectivity refers to availability of a data communication connection, wherein at least the first leg of communication is performed using a long-range wireless communication such as 2G, 3G, 4G, 5G or 6G cellular network communication, Long Range Wide Area Network (LoRaWan), narrowband-internet of Things (NB-IoT) or other Low Power Wide Area (LPWA) technology, satellite communications, or any other applicable existing or emerging long-range wireless communication technology. The long- range communication connection further comprises backbone connection such as an Internet connection towards a service.

[0046] In this context, the term server refers to one or more physical server computers and / or could-based server functionalities performing desired tasks. A telemetry server performs telemetry related tasks, such as telemetry data collection and analysis, and optionally diagnostics and controlling based on at least the received telemetry data.

[0047] The method according to embodiments of the disclosure applies a network echoing utility. As an example of a network echoing utility, well-known ping utility or a time or daytime protocol can be applied. In IPv6 network, also ping6 can be used. In this description, the term ping refers both to ping and ping6. Furthermore, any request sent to a service that is expected to send a response without a significant delay can be used as a network echoing utility in the context of this disclosure. For example, a request to provide information on current network time, using for example the Daytime Protocol or the Time Protocol can be used as a network echoing utility. Any suitable protocol or utility in which a server is expected to send, without significant delay, a response to a host sending a request message can be used as a network echoing utility in embodiments of this invention.

[0048] The figure 1 shows a telemetry arrangement in an elevator system comprising an elevator car 21 configured to travel along longitudinal dimension of a shaft 20. The elevator car is provided with a plurality of sensors (not shown), and sensors may be provided also at other functional elements of the elevator system. For example, a landing door at each landing level may be provided with one or more sensors configured to provide sensor data indicating operation conditions of the respective landing door. Each sensor preferably has a wireline or a short-range wireless connection towards a telemetry unit 100. Sensors carried by the elevator car may be part of an elevator control system, but sensors may also be part of an independent sensor system, associated with a telemetry unit 100. In the latter case the independent sensor system and the telemetry unit may form an entity, which is independent of elevator control system, such that said entity does not receive any information from the elevator control system?

[0049] The telemetry unit 100 is communicatively coupled to the sensors and configured to send telemetry data over a long-range wireless network to at least one a long- range wireless network node 30, such as a base station or an Evolved Node B (eNB) residing outside the shaft 20. Telemetry data is sent from the telemetry unit 100 over a long-range wireless communication connection by means of at least one long-range wireless communication device comprised in the telemetry unit 100. In this context, the term communication device refers to a long-range wireless communication device. The long-range wireless network node 30 provides the telemetry unit 100 with a data connection over the Internet 60 with one or more servers, such as a telemetry server 40 and a trusted server 50.

[0050] According to some embodiments, the telemetry unit 100 is an loT (Internet of things) controller that provides long-range wireless connectivity to the plurality of sensors. In this example, the telemetry unit 100 is shown on the roof of the elevator car 21. Alternatively, the telemetry unit may be placed anywhere in or on the elevator car 21.

[0051] It is known that signal strength of a long-range wireless communication network varies a lot in the shaft 20 as a function of the elevator car 21 position due construction of the shaft 20. For example, walls of the shaft 20 may be different at different locations and / or the car can travel below the ground level, where signal strength is weak and thus long-range wireless communication connection is poor. Thus, the telemetry device 100 might not be able to send telemetry messages when the car is moving or stationary at a position with poor long-range wireless connectivity. For example, in the exemplary elevator shaft 20, there are four different landing levels 25_0, 25_1, 25_2, 25_3. Landing level 25_0 may be a basement level with very poor long-range wireless connectivity. Thus, if the elevator car 21 is at the bottom landing level 25_0, no telemetry messages sent by the telemetry unit 100 can reach the long-range wireless network node 30, or just a portion of them may be received by the long-range wireless network node 30.

[0052] In addition to variation of long-range wireless connectivity due to structural reasons relating to the elevator shaft, there may be other reasons for variation of long-range wireless connectivity. For example, a network operator of the long- range wireless network may determine different priorities to different types of units within the wireless network. Mobile phones of human users may have been provided with higher priority than the communication device of a telemetry unit. Thus, if there are many mobile phones nearby, or even inside the elevator, for example during a rush-hour of office hours, all available connection capacity of the long-range wireless network may be consumed by the mobile phones such that the lower priority telemetry unit has poor or no connectivity at these times even at landing levels which have good connectivity for the telemetry unit at quiet hours when there are less mobile phones around using capacity of the long-range wireless communication network.

[0053] To ensure that telemetry messages can be sent by the telemetry unit 100 in a reliable manner, the communication device thereof preferably knows, whether telemetry messages can be reliable sent at the current position of the telemetry unit 100 so that these will be received by the remote entity, i.e. the telemetry server 40. Furthermore, it may be advantageous to recognize how different weekdays and times of day affect long-range wireless connectivity.

[0054] Figure 2 illustrates an exemplary telemetry data collection system of an elevator. The telemetry device 100 comprises at least one processor (CPU) 130 and at least one memory (MEM) 120, are operatively coupled to at least one long-range wireless communication device (L-Cll) 110 for providing long-range data communication towards said one of more servers 40, 50. The at least one long- range wireless communication device (L-Cll) 110 may be configured to operate in a plurality of different long-range wireless communication networks and / or to use a plurality of different long-range wireless communication protocols. According to some embodiments, the communication device 110 may be implemented as a plurality of separate long-range wireless communication devices. According to some embodiments, the communication device 110 may be an integrated communication device having capability to communicate over a plurality of different long-range wireless communication networks. The at least one processor 130 preferably runs an operating system. The at least one processor 130 is communicatively coupled to a plurality of sensors 150 and / or measurement devices (MD) 160. Coupling between the at least one processor 130 and the plurality of sensors 150 and / or measurement devices 160 may be wireline or it may be implemented using short-range wireless communication, in which case the telemetry device 100 is provided with at least one short-range wireless communication device (S-Cll) 120, facilitating short-range communication connections to sensors 150 and / or measurement devices 160. For example, short-range communication connections may use any known technologies such as Bluetooth, Wi-Fi and / or Zigbee.

[0055] Figure 3 illustrates a method of determining long-range connectivity of a long- range communication device of a telemetry unit.

[0056] In step 301, a plurality of network echoing utility messages are sent by the communication device of the telemetry unit. The plurality of network echoing utility messages is sent from a current position with respect to the longitudinal dimension of the shaft. In this context, current position preferably refers to the current position of the communication device, but since the communication device is part of the telemetry unit, which is attached on or in the elevator car, the current position of the communication device may be determined by the current position of any one of the elevator car, telemetry unit and / or communication device along the longitudinal dimension of the shaft. According to some embodiments, the current position simply refers to a landing level at which the elevator is currently at halt. According to some embodiments, telemetry messages and therefore also network echoing utility messages are only sent while the elevator is halted at one of the landing levels, for example for loading and / or unloading passengers, or just waiting for new passengers or a new elevator call.

[0057] Since the telemetry unit and its communication device are preferably attached to the elevator car, position of the communication device can be determined in relation to position of the elevator car and / or the telemetry unit. Current position may be determined using any known method of determining position of the elevator car, the telemetry unit and / or the communication device. For example, various sensor arrangements may be used for detecting that the elevator car is currently halted at a known landing level.

[0058] The plurality of network echoing utility messages is sent over at least one long- range communication network towards at least one known server. If there is more than one long-range communication network available for use by the telemetry unit, a plurality of network echoing utility messages may be sent over each long-range communication network. However, it is preferable that a single long-range communication network is tested at a time in order not to generate a risk of mixing up network echoing utility reply messages received via different long-range communication networks.

[0059] In step 302, network echoing utility reply messages are received via the communication device from the at least one known server in response to sending the plurality of network echoing utility messages over the long-range communication network. In step 303, a connectivity value is determined at the current position of the long- range communication device at each of said plurality of longitudinal positions based at least on the number of network echoing utility reply messages received via the communication device from the at least one known server in response to sending the plurality of network echoing utility messages at the respective longitudinal position.

[0060] In step 304, the determined connectivity value is stored in the at least one memory of the telemetry device in association with an indicator of the current position and, if more than one long-range communication networks are in use, with an identifier of the respective long-range communication network, so that the telemetry unit has the connectivity value available for future use, and the telemetry unit can use stored connectivity values to determine when it is best to send telemetry messages so that these are received by the desired telemetry server as intended.

[0061] According to some embodiments, the connectivity value is determined at least at the plurality of landing levels of an elevator car traveling within the elevator shaft along longitudinal dimension thereof.

[0062] Figure 4 illustrates a method of determining long-range connectivity of at least one long-range communication device of a telemetry unit according to some embodiments. Steps 301, 302, 303 and 304 are as described above. After completing determining connectivity value at one position with respect to one long-range communication network, the method proceeds to step 401, in which at least one of the following is performed: a) position of the at least one communication device is changed by moving the elevator car to another landing level, and b) switch from using a first long-range wireless communication network to using a second long-range wireless communication network so that long-range connectivity can subsequently be tested for the second long-range communication network. Control of operation of the communication device(s), including but not limited to switching between operating using different long- range wireless communication networks, may be implemented by controlling the operation of the communication device or by switching to use another of a plurality of available communication devices.

[0063] According to some embodiments, plurality of network echoing utility messages is sent over at least two long-range communication networks alternatively. As long as the network echoing utility messages and the network echoing utility reply messages are identified with a sequence number, the processor of the telemetry device is capable of distinguishing which network echoing utility reply messages were sent using which long-range wireless communication network, and thus determine long-range connectivity to each tested long-range wireless communication network.

[0064] According to some embodiments, the connectivity value is calculated based on one or more ratios determined on basis of received network echoing utility reply messages and sent network echoing utility messages at the respective longitudinal position. Non-limiting examples of such ratios are (send messages) / (received messages) and / or (received messages) / (sent messages).

[0065] According to some embodiments, the connectivity value is further determined based on round trip times of the network echoing utility messages and respective network echoing utility reply messages. According to some embodiments, an auxiliary connectivity value is further determined based on round trip times of network echoing utility messages and respective network echoing utility reply messages.

[0066] According to some embodiments, the process of sending network echoing utility messages, receiving network echoing utility reply messages and determining connectivity value(s) is repeated at a plurality of different times of day, and optionally also on different weekdays. This enables taking into account effects on long-range connectivity caused by overall communication network traffic, for example due to rush hours, business hours, network operator's prioritization and so on.

[0067] In the following tables, connectivity value is shown as a percentage, representing ratio determined as number of received network echoing utility reply messages divided by the respective number of sent network echoing utility messages.

[0068] Table 1 illustrates a simplified example of connectivity values in the form of a table that can be stored in the at least one memory of the telemetry device.

[0069] Table 1

[0070] By utilizing connectivity values of the Table 1, the telemetry unit may determine that when at landing level 0, it is preferred not to send telemetry messages at all, because likelihood that these will not be successfully received by the telemetry server is low. Instead, the telemetry unit may decide to wait for a while, temporarily store telemetry data obtained at the landing level 0 in its memory and wait until the elevator moves to floor 3 or 4 to have good connectivity value, so that it can be expected that the telemetry message will always be successfully received by the telemetry server. Furthermore, in this example, the telemetry unit may decide to use network 2 at the third floor and network 1 at the fourth floor to have best possible connectivity for maximizing probability that best effort telemetry messages will be successfully delivered. On the other hand, if the elevator car was stuck at landing level 0, so that it cannot move to any other floors, the telemetry unit may decide to use the network 1 and to improve likelihood to success, send three or four copies of each message over the network 1 in effort to make sure that at least one of these messages is actually received by the telemetry server.

[0071] Table 2 illustrates a simplified example of connectivity values in form of a table.

[0072] Table 2

[0073] In the Table 2, just a single network is shown for simplicity, and times of day and days of week have been categorized into three main categories; the telemetry device then has further stored data on which days and hours are considered as office hours, which are considered as rush hours and / or which are night hours or weekend hours when there are few if any mobile phones around that cause workload to the network that reduces connectivity for the telemetry use, for any reason.

[0074] Having such data available on long-range connectivity, the telemetry device may decide to postpone sending telemetry messages during rush hours and prefer upper floors for sending telemetry messages at any time. Any telemetry messages of a type that does not require real-time processing at the telemetry server may be postponed until office hours are over. On the other hand, telemetry messages that should be processed quickly may be repeated a few times, if sent during office or rush hours, and sending is preferably scheduled whenever the elevator is at one of the higher landing levels.

[0075] Although the above Table 2 determines just three "time categories", any number of time categories may be determined. For example, the long-range connectivity may be determined on hourly basis.

[0076] According to some embodiments, connectivity values are determined for a plurality of different long-range communication technologies, such as 2G, 3G, 4G and / or 5G telecommunication network. This enables the telemetry unit to utilize different characteristics of different technologies. For example, 3G network has a lower data communication capacity and works slower than a 4G network, but it may provide more reliable connection because it uses longer wavelength, so that 3G signals can penetrate buildings and the shaft better than 4G signals. ON the other hand, base stations or eNBs of different cellular networks may be located mutually in different places, which also affects connectivity of the telemetry unit towards these base stations or eNBs. Furthermore, network operators may have different service policies, for example on how different types of traffic are handled, and if some types of traffic have lower priorities than others. A typical case is that telemetry traffic has a lower priority than human user's mobile phone traffic. This may cause problems in connectivity for telemetry especially during busy hours, such as office hours or rush hours, large events and so on, whenever a lot of people with a lot of mobile phones are present.

[0077] According to some embodiments, a connectivity map is generated based on the connectivity values. The connectivity map comprises the plurality of determined connectivity values representing one or more connectivity values at each of the plurality positions. If connectivity values are also determined for different times of day and / or different weekdays, the long-range connectivity map further comprises connectivity values at a plurality of times of day and / or different weekdays. According to some embodiments, the communication device is configured to delay sending of telemetry messages concerning any one of an elevator traveling withing the elevator shaft and the elevator shaft, or to keep telemetry messages in a sending buffer, until the communication device is at a position at which the connectivity value exceeds a threshold. For example, a minimum threshold of 100%, 95%, 90%, 85%, 80% or 75% connectivity value may be required before telemetry messages are sent.

[0078] As known to a skilled person, communication network load and resources are not forever stable, but change continuously. Therefore, it is preferable that long- range connectivity is regularly redetermined so that the connectivity data stored at the telemetry unit is up to date. However, no excess updating should be made to avoid unnecessary loading of the network by flooding it with network echoing utility messages. Updating the connectivity values may be performed for example weekly or monthly, or whenever a significant change in the network or communication performance has been detected or is known to have been made.

[0079] Figure 5 illustrates a non-limiting example on utilizing the connectivity data for controlling sending of telemetry messages.

[0080] In step 500, telemetry data is obtained by one or more sensors and obtained data is collected by the telemetry unit.

[0081] In step 501, the current position is determined. The current position is preferably determined using the same position determination method that was used while determining connectivity values.

[0082] In step 502, at least one connectivity value at the determined position is obtained. If any of the at least one obtained connectivity values is determined to be good, i.e. above a threshold, a long-range connection corresponding to one of the good connectivity values is applied and a telemetry message is sent in step 503. If there are more than one long-range communication networks that provide good connectivity at the current position, one of these is selected. Additional selection criteria may be considered. Such additional selection criteria may be for example best of all available connectivity values or other prioritization criteria such as a predetermined priority order of different long-range connectivity methods. Such prioritization criteria may be based for example on cost of communication. Selection of the long-range connection network is based on the obtained connectivity values, and the selection may be made by the at least one processor of the telemetry unit and / or by the at least one connection device.

[0083] If it is determined in step 502 that there is no long-range connectivity available at this position, it is further determined in step 504 whether the elevator car and thus the telemetry unit has a possibility to move to another position. This step may be based on information obtained from the elevator's control system, but various sensor and other telemetry type information may be sufficient. If it is determined that the telemetry unit can move to another position with hopefully a better connectivity, sending of telemetry messages is delayed, and a wait period is applied as illustrated by step 505. This may be a predetermined wait period or simply a wait state until it is determined in step 501 that the current position has been changed.

[0084] On the other hand, if it is determined that it is not possible to move for example due to a problem detected in the elevator system, the process may proceed to step 506 in which a plurality of copies of the same telemetry message is sent to improve likelihood that at least one of these telemetry messages is successfully delivered. Instead of determining whether it is possible to move to find a position with good connectivity, a maximum allowed delay for sending any telemetry messages may be determined. If such a delay condition is used, it may be determined that after a predefined delay, a plurality of copies of telemetry messages can be sent at a location with poor connectivity. According to some embodiments, an idle elevator car can be controlled to move to a position with good connectivity solely for the purpose of reliably sending telemetry message(s) .

[0085] It is apparent to a person skilled in the art that as technology advanced, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.

Claims

Claims1. A method for determining long-range connectivity of a telemetry unit associated with an elevator car, the method comprising:- sending, via a long-range wireless communication device (communication device) of the telemetry unit, a plurality of network echoing utility messages over a long-range wireless communication network towards at least one known server at each of a plurality of positions within the elevator shaft,- receiving, via the communication device, one or more network echoing utility reply messages in response to sending said plurality of network echoing utility messages, and- determining, by the telemetry unit, a connectivity value at each of said plurality of positions based at least on number of network echoing utility reply messages received from the at least one known server in response to said sending the plurality of network echoing utility messages at the respective position.

2. The method according to claim 1, wherein the connectivity value is determined at least at the plurality of positions associated with landing levels of an elevator car configured to travel between said landing levels in longitudinal dimension of an elevator shaft.

3. The method according to claims 1 or 2, wherein the connectivity value is calculated as at least one ratio calculated between received network echoing utility reply messages and the plurality of network echoing utility messages sent at the respective position.

4. The method according to claim 3, further comprising determining the connectivity value or an auxiliary connectivity value based on roundtrip times of network echoing utility messages and respective network echoing utility replies.

5. The method according to any one of claims 1 to 4, further comprising repeating said sending the plurality of network echoing utility messages and said determining the connectivity value at a plurality of different times of day and / or different weekdays.

6. The method according to any one of claims 1 to 5, further comprising determining a plurality of connectivity values for at least one of: a plurality of long-range communication technologies, such as any of 3G, 4G, 5G and / or 6G telecommunication network, Long Range Wide Area Network (LoRaWan), narrowband-internet of Things (NB-IoT), Low Power Wide Area (LPWA) technology and satellite communications, a plurality of different network operators, a plurality of different base stations of the long-range communication network.

7. The method according to any one of claims 1 to 6, further comprising generating a connectivity map comprising the plurality of connectivity values determined at each of the plurality of positions, and when dependent on claim 5, the connectivity map further comprising connectivity values at a plurality of different times of day and / or different weekdays.

8. The method according to any one of claims 1 to 7, further comprising delaying or buffering sending of telemetry messages until the communication device is at a position at which the connectivity value exceeds a threshold.

9. The method according to any one of claims 1 to 8, when depending on claim 6, further comprising selecting the long-range wireless communication technology, network operator and / or base station to be used for sending telemetry messages based on the plurality of connectivity values.

10. The method according to any one of claims 1 to 9, further comprising sending a plurality of copies of the telemetry message if the telemetry message is sent at a position at which the connectivity value is below a threshold.

11. A telemetry unit associated with an elevator car and configured to determine long-range connectivity, the telemetry unit comprising:- at least one long-range wireless communication device (communication device) configured:- to send, a plurality of network echoing utility messages over a long-range wireless communication network towards at least one known server at each of a plurality of positions within the elevator shaft,- to receive one or more network echoing utility reply messages in response to sending said plurality of network echoing utility messages,- at least one processor configured:- to determine a connectivity value at each of said plurality of positions based at least on number of network echoing utility reply messages received from the at least one known server in response to said sending the plurality of network echoing utility messages at the respective position.

12. The telemetry unit according to claim 11, wherein the at least one processor is configured to determine the connectivity value at least at the plurality of positions associated with landing levels of an elevator car configured to travel between said landing levels in longitudinal dimension of an elevator shaft.

13. The telemetry unit according to claim 11 or 12, wherein the at least one processor is configured to calculate the connectivity value as at least one ratio calculated between received network echoing utility reply messages and the plurality of network echoing utility messages sent at the respective position.

14. The telemetry unit according to claim 13, wherein the at least one processor is configured to determine the connectivity value or an auxiliary connectivity value based on round trip times of network echoing utility messages and respective network echoing utility replies.

15. The telemetry unit according to any one of claims 11 to 14, wherein the at least one communication device is configured to send the plurality of network echoing utility messages and the at least one processor is configured to determine said connectivity value repeatedly at a plurality of different times of day and / or different weekdays.

16. The telemetry unit according to any one of claims 11 to 15, wherein the at least one processor is configured to determine a plurality of connectivity values for at least one of: a plurality of long-range communication technologies, such as any of 3G, 4G, 5G or 6G telecommunication network, Long Range Wide Area Network (LoRaWan), narrowband-internet of Things (NB-IoT), Low Power WideArea (LPWA) technology and satellite communications, a plurality of different network operators, a plurality of different base stations of the long-range communication network.

17. The telemetry unit according to any one of claims 11 to 16, wherein the at least one processor is configured to generate a connectivity map comprising the plurality of connectivity values determined at each of the plurality of positions, and when dependent on claim 15, the connectivity map further comprises connectivity values at a plurality of different times of day and / or different weekdays.

18. The telemetry unit according to any one of claims 11 to 17, wherein the at least one communication device and / or the at least one processor is configured to delay or buffer sending of telemetry messages, until at least one of the at least one communication device is at a position at which the connectivity value exceeds a threshold.

19. The telemetry unit according to any one of claims 11 to 18, when depending on claim 16, wherein the at least one communication device and / or the at least one processor is configured to select the long-range wireless communication technology, network operator and / or base station to be used for sending telemetry messages based on the plurality of connectivity values.

20. The telemetry unit according to any one of claims 11 to 19, wherein the at least one communication device is configured to send a plurality of copies of the telemetry message if the telemetry message is sent at a position at which the connectivity value is below a threshold.

21. A computer program product comprising computer executable code configured, when executed by at least one processor and at least one communication device of a telemetry unit of an elevator, to cause the telemetry unit to perform the method according to any one of claims 1 to 10.

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