WO2019175835A1

WO2019175835A1 - Modification of a functional split in case of insufficient availability of resources

Info

Publication number: WO2019175835A1
Application number: PCT/IB2019/052094
Authority: WO
Inventors: Luca Valcarenghi; Nicola Sambo; Koteswararo KONDEPU; Francesco GIANNONE; Piero Castoldi
Original assignee: Scuola Superiore Di Studi Universitari E Di Perfezionamento Sant'anna
Priority date: 2018-03-14
Filing date: 2019-03-14
Publication date: 2019-09-19
Also published as: IT201800003571A1

Abstract

A method for restoring a connection of a telecommunication network (100) for fifth generation services, or 5G. The telecommunication network comprises a central controller arranged to identify a condition of availability of resources of the network and a plurality of nodal devices connected by at least one path of data connection, wherein each nodal device is adapted to work alternatively, or at the same time, as data transmitter, data receiver, or transit node for the path of data connection between a sender and a receiver. The telecommunication network is adapted to carry out at least one data traffic between a data transmitter and a data receiver. For each data traffic, the data transmitter is adapted to process a first predetermined amount of data and the data receiver is adapted to process a second predetermined amount of data, said first and said second predetermined amount of data being related to each other by a functional split. The central controller is adapted to set, for each data traffic, the functional split. The method comprises a step of identifying (301), by the central controller, a condition of availability of resources of the network, and a step, in case that the availability of resources is insufficient to carry out the data traffic, of modifying (304) said functional split for adjusting the first and the second predetermined amount of data processed, respectively, by the data transmitter and by the data receiver.

Description

MODIFICATION OF A FUNCTIONAL SPLIT IN CASE OF INSUFFICIENT AVAILABILITY OF RESOURCES

DESCRIPTION

Field of the invention

The present invention relates to the field of telecommunications, and, in particular the invention relates to a method and a system for restoring a connection of a telecommunication network for fifth generation services.

Description of the prior art

As is known, in telecommunications networks, failures are not rare events, as is the degradation of the transmitted signal .

In general, techniques for surviving breakdowns are distinguished in protection and restoration techniques ("IP restoration vs. WDM protection: is there an optimal choice?" A. Fumagalli and L. Valcarenghi, Nov/Dec 2000) .

In the first case the backup resources are established when the main connection is established (working) . In the second case they are searched once the fault has occurred. In a multilevel network, fault survival techniques can be implemented at every level. In particular, escalation techniques are also implemented to coordinate the reaction to the failure of the various levels. The types of failures can be multiple such as a failure of a cable, of a node, of the software used to operate a node and even physical degradation of a cable due to aging. In this last case, techniques have been proposed which, by changing the transmission parameters (often reducing the transmission capacity) , are able to keep the connection active ("BER Degradation Detection and Failure Identification in Elastic Optical Networks," A. Vela et al . , 2017) . However, this system, by reducing the speed of data transmission to the advantage of signal strength, may lead to the interruption of services that require a higher transmission speed. In this case, therefore, the data traffic is interrupted anyway, reducing the overall reliability of the network.

Fifth generation mobile networks (5G) are multilevel networks. In fact, several protocol levels process the packet in its transmission between source (mobile user) and destination (server) . Each protocol level implements specific functions. In the current standardization of 5G it is possible to appropriately distribute the functions implemented by the radio base station (called Next Generation Node B, gNB) in at least two units: a remote unit called Distributed Unit (DU) and a centralized one called Central Unit (CU) . This feature is called "functional split". Depending on the type of functions assigned to each unit, there are different bandwidth and latency requirements. Furthermore, DU and CU can be virtualized based on recent ETSI NFV-based frameworks.

Therefore failures can occur at various levels.

In the documents "Flexible functional split in 5G networks" by Davit Harutyunyan et al. published on 11/26/2017 and "FlexCRAN: A flexible functional split framework over ethernet fronthaul in Cloud-RAN" by Chia-Yu Chang et al . published on 05/21/2017 the concept of "flexible functional split" is introduced, i.e. the coexistence of different functional splits that can be appropriately selected depending on the type of service requested in terms of latency and bandwidth.

However, neither document addresses in any way the technical problem of a network failure, due for example to a physical deterioration of the wiring. Summary of the invention

It is therefore a feature of the present invention to provide a method for restoring a connection of a telecommunication network for fifth generation services which ensures the survival of a service of data traffic following a failure of the system, even when, owing to this failure, it is necessary to reduce the transmission speed on the line below the speed necessary to the service itself.

It is also a feature of the present invention to provide a telecommunication network that carries out said method. These and other objects are achieved by a method for restoring a connection of a telecommunication network for fifth generation services, or 5G, said telecommunication network comprising:

— a central controller and arranged to identify a condition of availability of resources of said network;

— a plurality of nodal devices connected by at least one path of data connection, each nodal device is configured to work alternatively, or at the same time, as:

— data transmitter;

— data receiver;

— transit node for said path of data connection between a transmitter and a receiver; said telecommunication network arranged to carry out at least one data traffic between a data transmitter and a data receiver, for each data traffic said data transmitter configured to process a first predetermined amount of data and said data receiver configured to process a second predetermined amount of data, said first and said second predetermined amount of data being related to each other by a functional split,

said central controller arranged to set, for said or each data traffic, said functional split; whose main feature is that it comprises the steps of:

— identifying, by said central controller, a condition of availability of resources of said network;

— in case that said availability of resources is insufficient to carry out said at least one data traffic, modifying by said central controller said functional split for adjusting said first and said second predetermined amount of data processed, respectively, by said data transmitter and by said data receiver.

This way, the present invention allows keeping active the data traffic, even when, following a failure and/or the application of known methods of restoring the network, there is a reduction of the data transmission capacity. Therefore, the invention allows a higher probability of maintaining the service delivered following a failure of the network, with respect to the prior art.

In particular, to said data traffic a working status is assigned, and, upstream of said step of modifying said functional split, a step is provided of changing said status of said data traffic.

Such step, already known, can be used before modifying the functional split to strengthen the data connection. It is therefore a synergic operation with that provided by the present invention.

Advantageously, upstream of said step of modifying said functional split, a step is provided of changing said path of data connection between a transmitter and a receiver.

Such step, already known, makes it possible to search for a connection path with a greater capacity, so as to have to resort to a smaller variation in the functional split. It is therefore a synergic operation with that one provided by the present invention.

According to another aspect of the invention, a telecommunication network for fifth generation services, or 5G, comprises:

— a plurality of nodal devices connected by at least one path of data connection, each nodal device configured to work alternatively, or at the same time, as:

— data transmitter;

— data receiver;

said central controller arranged to set, for said or each data traffic, said functional split;

whose main feature is that said central controller is adapted, in case that said availability of resources is insufficient to carry out said at least one data traffic, to modify said functional split for adjusting said first and said second predetermined amount of data processed, respectively, by said data transmitter and by said data receiver.

In particular, the path of data connection is made of optical fibres.

Brief description of the drawings

Further characteristic and/or advantages of the present invention are brighter with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

— Fig. 1 schematically shows an example of telecommunication network for fifth generation services ;

— Fig. 2 shows the steps of a method for restoring, following a failure, a connection of a telecommunication network for fifth generation services, according to the invention.

Description of a preferred exemplary embodiment

In Fig. 1 is schematically shown an example of telecommunication network 100 for fifth generation services.

The telecommunication network comprises a plurality of nodal devices connected through a plurality of paths of data connection. Such paths are made, for example, by means of optical fibre or other means for data connection.

Each nodal device is adapted to work alternatively, or at the same time, as data transmitter, data receiver, or transit node for the path of data connection between a transmitter and a receiver.

The telecommunication network 100 is adapted to carry out at least one data traffic between a data transmitter and a data receiver. For each data traffic the transmitter is adapted to process a first predetermined amount of data and the receiver is adapted to process a second predetermined amount of data. The first and the second predetermined amount of data are related to each other by a functional split. Such functional split is normally predetermined by a central controller in a data traffic setting phase and it is not subsequently modified.

The present invention provides instead the possibility that the central controller, following the identification of a fault and the consequent insufficiency of network resources, appropriately modifies the functional split in order to vary the first and the second predetermined amount of data processed, respectively by the data transmitter and by the data receiver.

For example, the amount of data processed by the transmitter can be reduced, while that processed by the receiver can be increased. In this way, the amount of processed data that is transmitted from the transmitter to the receiver is reduced, allowing data traffic to be kept active, and therefore the service provided, despite the reduced transmission speed.

In the example in the figure a fault survival technique based on an ETSI NFV-MANO architecture is described. The connection path connecting the central controller and the nodal devices is monitored by a monitoring network designed to detect and anticipate the loss of transmission quality of the connection path and to notify the Virtual Network Function Manager (VNFM) /Virtual Infrastructure Manager (VIM) . In particular, in the event that the connection presents degradation of data traffic, VNEM/VIM notifies NFV

Orchestrator (NFVO) which reacts by imposing a reconfiguration of the network, varying the functional split between the amount of data processed by the receiver and the amount of data processed by the transmitter.

Fig. 2 shows a block diagram relative to the steps of a method [300] for restoring a connection of a telecommunication network for fifth generation services following a failure. This failure can lead, for example, to a reduction in the transmission speed on the line below the minimum speed values required for the operation of the service .

In particular, the method [300] provides a first step of identifying a possible failure in the data connection path between a data transmitter and a data receiver [301] .

If the availability condition is able to guarantee the data traffic necessary for the service to function, a recovery occurs in the data connection path. In the event that the availability condition is not able to guarantee data traffic, a reduction in the capacity of the data connection path is performed to the advantage of increasing the strength of the transmitted signal [302] .

In the event that the new capacity of the data connection path is sufficient to guarantee the current functional split, then the data path is restored. If, on the other hand, this capacity is insufficient, then a path recovery is performed by a deviation in an alternative data connection path [303] .

In the case in which also the capacity of the alternative path is not sufficient, a redefinition of the distribution of the functions implemented by the base station [304] is carried out with consequent restoration of the path.

Alternatively, the data connection path is disconnected.

The foregoing description some exemplary specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation .

Claims

1. A method for restoring a connection of a telecommunication network (100) for fifth generation services, or 5G, said telecommunication network comprising :

— a central controller arranged to identify a condition of availability of resources of said network;

— data transmitter;

— data receiver;

— transit node for said path of data connection between a transmitter and a receiver; said telecommunication network (100) arranged to carry out at least one data traffic between a data transmitter and a data receiver, for each data traffic said data transmitter configured to process a first predetermined amount of data and said data receiver configured to process a second predetermined amount of data, said first and said second predetermined amount of data being related to each other by a functional split,

said method also comprising the steps of:

— in case that said availability of resources is insufficient to carry out said at least one data traffic, modifying by said central controller said functional split for adjusting said first and said second predetermined amount of data processed, respectively, by said data transmitter and by said data receiver;

said method characterized in that to said data traffic a working status is assigned,

and in that, upstream of said step of modifying said functional split, a step is provided of changing said status of said data traffic.

2 . The method for restoring a connection of a telecommunication network (100), according to claim 1, wherein, upstream of said step of changing said functional split, a step is provided of changing said path of data connection between a transmitter and a receiver .

3 . The method for restoring a connection of a telecommunication network (100), according to claim 1, wherein said path of data connection is made of optical fibres .

4 . A telecommunication network (100) for fifth generation services, or 5G, said telecommunication network comprising :

— data transmitter;

— data receiver;

said telecommunication network (100) characterized in that said central controller is adapted, in case that said availability of resources is insufficient, to carry out said at least one data traffic, to modify said functional split for adjusting said first and said second predetermined amount of data processed, respectively, from said data transmitter and by said data receiver.

5. The telecommunication network (100), according to claim

4, wherein said path of data connection is made of optical fibres.