CROSS REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 national stage application of PCT International Application No. PCT/SE2016/050260 filed on Mar. 30, 2016, the disclosure and content of which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to methods and nodes configured for control link definition in a networked control system, wherein the networked control system comprises a controlling node, a controlled process node and a Machine Type Communication, MTC, wireless communication link between the controlling node and the controlled process node.

BACKGROUND

3GPP Long Term Evolution, LTE, is the fourth-generation mobile communication technology standard developed within the 3rd Generation Partnership Project, 3GPP, to improve the Universal Mobile Telecommunication System, UMTS, standard to cope with increasing requirements in terms of improved services such as higher data rates, improved efficiency, and lowered costs. LTE-Advanced and the fifth-generation, 5G, mobile communication technology standards are developed to meet further requirements in terms of improved services. One of the main tasks for 5G is to reduce latency, and improve throughput and capacity compared to LTE. This is achieved by increasing the sample rate and bandwidth per carrier. 5G is also focusing on use of higher carrier frequencies i.e. above 5-10 GHz

In a typical cellular radio system, wireless devices or terminals also known as mobile stations and/or User Equipment units, UEs, communicate via a Radio Access Network, RAN, to one or more core networks. The Universal Terrestrial Radio Access Network, UTRAN, is the radio access network of a UMTS and Evolved UTRAN, E-UTRAN, is the radio access network of an LTE system. In an UTRAN and an E-UTRAN, a UE is wirelessly connected to a Radio Base Station, RBS, commonly referred to as a NodeB, NB, in UMTS, and as an evolved NodeB, eNB or eNodeB, in LTE. An RBS is a general term for a radio network node capable of transmitting radio signals to a UE and receiving signals transmitted by a UE.

In LTE evolution and in future 5G systems, one goal is to open up for new use cases involving advanced applications of automatic control. Automatic control is a field of science focused on getting systems and processes to behave as intended and according to specification, despite shortcomings in e.g. mechanical design, motor performance and sensor accuracies. Automatic control algorithms can be based on feedback or feedforward or both.

Of special interest here is a technology denoted networked control systems, NCS, where the controller and the controlled process are located at different sides of an interface, typically a wireless interface connecting a controlling node, e.g., an RBS, and a controlled process node, e.g., a UE, by means of a wireless communication link. The real-time requirements of the communication links may vary significantly between different applications. Control of robots for component mounting on printed circuit boards have bandwidths approaching a kHz and cannot tolerate delays of more than a fraction of a millisecond when operated remotely over wireless interfaces. The same is true for industrial robots and e.g. ABS brakes in cars. On the other hand, crane control for container logistics in ports has bandwidths of the order of seconds, and these systems can tolerate much longer delay.

LTE architecture can provide a desired Quality of Service, QoS, for a wide range of services and this will also be the case for the 5G mobile communication standards. However, for control applications the requirements of each controlled process may be quite unique and in a networked control system implying a need for specific communication link characteristics. Present architecture and QoS definitions do not make provisions for the specific requirements following from a networked control system, NCS.

SUMMARY

In an application involving a networked control system, characteristics of the wireless communication link affect the overall controller process; thus, there is a need for improving and adapting capabilities of the communication link in order to achieve intended process dynamics in the controlled process.

It is an object of the present disclosure to configure a network control system in support of a particular controlled process. In particular, it is an object of the disclosure to provide embodiments supporting configuration of the wireless communication link between a controlling node and a controlled process node.

This object is obtained by a method, performed in a controlling node, for configuring a networked control system, NCS, comprising the controlling node, a controlled process node and a Machine Type Communication, MTC, wireless communication link between the controlling node and the controlled process node. The method comprises to obtain process characteristics for a process performed in the controlled process node and NCS requirements for an automatic control process to be performed in the NCS. The controlling node also determines link capability requirements for the MTC wireless communication link based on the process characteristics and the NCS requirements. One or more quality of service, QoS, parameters of the MTC wireless communication link are customized based on the determined link capability requirements.

The proposed solution enables improved control and reliability in control of a process controlled from a networked control system. The MTC wireless communication link is appropriately set, providing for a resource effective utilization. Furthermore, performing the link setting procedure from the controlling node provides for network operator control of the link setting procedure, combining input from the process operator and control system operator in order to optimize utilization of network resources while providing a customized wireless communication link. Finally, an automated method of configuring the NCS, allows an automatic and consistent large scale deployment of controllers to processes in need of automatic control; providing for critical MTC applied to automatic control.

According to aspects of the disclosure, the obtaining of process characteristics comprises receiving process characteristics from the controlled process node, while the obtaining of NCS requirements comprises receiving NCS requirements from the controlled process node and/or from an NCS requirements repository having a communications interface to the controlling node.

Accordingly, process characteristics that are readily available to the controlled process node, e.g., through measurements in the controlled process node, are obtained from the controlled process node, while controller requirements are obtained where they are most readily available.

According to aspects of the disclosure, process characteristics comprise one or more of a cross over frequency, a process delay, a non-linearity, and a range of inputs and outputs of the process.

Thus, the configuration of the networked control system is based on process characteristics determined as characterizing from a perspective of controller design and in the determining of link quality requirements.

According to other aspects of the disclosure, the NCS requirements comprises one or more of a closed loop bandwidth, a closed loop static error, a static or dynamic closed loop disturbance suppression and a robustness to modelling errors.

Accordingly, in the configuration of the networked control system a number of common control requirements parameters have been identified as characterizing for controller design purposes and are taken into consideration as part of the proposed configuring.

According to further aspects of the disclosure, the link capability requirements comprises one or more of a maximum delay of the link, a sampling period, a maximum block error rate and a bandwidth/data rate of the link.

According to another aspect of the disclosure, the customizing comprises customizing Guaranteed Bit Rate (GBR) or non-Guaranteed Bit Rate (non-GBR), Priority Handling, Packet Delay Budget and/or Packet Error Loss.

Thus, the disclosed solution provides for customizing and controlling a number of well-known QoS aspects of the communications link, or rather for controlling QoS for radio bearers of the PDN connection within the Networked Control System.

According to an aspect of the disclosure, the method for configuring the NCS further comprises to initiate the MTC wireless communication link between the controlling node and the controlled process node and to provide one or more control signals to the controlled process node based on one or more feedback signals received from the controlled process node.

The object of the disclosure is also obtained by a computer program comprising computer program code which, when executed in a controlling node, causes the controlling node to execute the above disclosed method aspects.

The object of the disclosure is also obtained by a controlling node configured to support configuration of a networked control system, NCS, comprising the controlling node, a controlled process node and a Machine Type Communication, MTC, wireless communication link between the controlling node and a controlled process node. The controlling node comprises radio circuitry arranged for establishing the MTC wireless communication link; communications circuitry arranged to obtain process characteristics for a process to be performed in the controlled process node and NCS requirements for an automatic control process to be performed in the NCS; and processing circuitry arranged to determine link capability requirements for the MTC wireless communication link based on the obtained process characteristics and the NCS requirements; and customize one or more quality of service parameters of the MTC wireless communication link based on the determined link capability requirements.

The advantages and benefits presented in relation to method aspects above are of course also applicable to the computer program configured to execute the method and the controlling node, comprising the computer program.

Furthermore, the object of the disclosure is obtained by a method performed in a controlled process node, of supporting configuration of a networked control system, NCS, comprising the controlled process node, a controlling node and a Machine Type Communication, MTC, wireless communication link between the controlled process node and the controlling node. The method comprises receipt, from the controlling node, of one or more customized quality of service, QoS, parameters for the MTC wireless communication link, and establishment of at least one MTC wireless communication link to the controlling node.

According to an aspect of the disclosure, the method further comprises receipt, from the controlling node, of a request for process characteristics for a process to be performed in the controlled process node and NCS requirements for an automatic control process to be performed in the NCS. A response is sent to the controlling node comprising the requested process characteristics and NCS requirements.

A computer program comprising computer program code which, when executed in a controlled process node, causes the controlled process node to execute the above disclosed method aspects also provide the above stated object of the disclosure.

A controlled process node is configured to support configuration of a networked control system, NCS, comprising the controlled process node, a controlling node and a Machine Type Communication, MTC, wireless communication link between the controlled process node and a controlling node. The controlled node comprises communications circuitry and processing circuitry. The controlled process node is configured to receive, from the controlling node, one or more customized quality of service, QoS, parameters for the MTC wireless communication link and to establish at least one MTC wireless communication link to the controlling node.

The controlled node embodiments provide corresponding benefits to those described above for the controlling node.

The disclosed automatic procedure allows for consistent large scale deployment of controllers to processes in need of automatic control, thereby enabling critical a networked and distributed solution to automatic control in general.

