WO2013053376A1

WO2013053376A1 - A method of and apparatus for establishing bearer attributes

Info

Publication number: WO2013053376A1
Application number: PCT/EP2011/067619
Authority: WO
Inventors: Patrick Maguire
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2011-10-10
Filing date: 2011-10-10
Publication date: 2013-04-18

Abstract

The invention provides a method of establishing bearer attributes (ARP, QCI) of a bearer in a communication network in response to a priority data transfer service (e.g. medical reporting service) request. In a first step, a high access priority attribute (ARP value) is assigned (76) to a bearer associated with the service request, providing preferential access to network resources for the bearer). In a second step, a priority data quality of service class attribute (QCI) is assigned (78) to a bearer associated with the service request, providing low delay, error intolerant data transfer for the priority data transfer service.

Description

A METHOD OF AND APPARATUS FOR ESTABLISHING BEARER ATTRIBUTES

TECHNICAL FIELD

The invention relates to the establishment of bearer attributes of a bearer in a communication network. In particular the invention relates to the establishment of bearer attributes of a bearer in a communication network for use in an application requiring low delay, error intolerant data transfer with priority access to network resources independent of network load.

BACKGROUND

In existing communication networks, bearers are established in response to a service request to carry data connected with the service request through the communication network. Each bearer is associated with a particular quality of service, which describes parameters such as the data rate, error rate and delay for the data being transferred with that quality of service.

Figure 1 illustrates bearers within an exemplary network 10 implementing the evolved packet system (EPS) used in, for example, the Long Term Evolution (LTE) communication network standardised by the 3 Generation Partnership Project (3GPP). In such a network a "virtual connection" is established between, for example, a user equipment (UE) 12 and a packet data network gateway (P-GW) 14 of the communication network 10 before any traffic data can be sent between the user equipment (UE) 12 and a peer entity 16 via the communication network 10 and an external network 18 such as the internet. This virtual connection is called a bearer 20, and the bearer 20 provides a bearer service transporting traffic data with specific quality of service attributes.

It should be noted that the bearer 20 does not carry a full end-to-end service 22 between the user equipment (UE) 12 and a peer entity 16, because there is also an external bearer 24 which carries the traffic data in the external network 18, such as the internet. However, the external bearer 24 lies outside the scope of the invention and is familiar to a skilled person, and so will not be described in more detail.

The bearer 20 spans several interfaces that use different transport protocols and therefore in practice the bearer 20 is implemented as a number of lower level bearers, for example: a radio bearer 26 carrying data over an air interface between the user equipment (UE) 12 and an E-UTRAN Node B (eNB) 28; and an SI bearer 30 carrying data over an SI interface between the E-UTRAN Node B (eNB) 28 and the serving gateway (S-GW) 32. If the serving gateway (S-GW) 32 and the packet data network gateway (P-GW) 14 are not co-located, a S5/S8 bearer 34 carrying data over an S5/S8 interface is also provided.

As indicated above, bearers are established in response to a service request to carry data connected with the service request through the communication network. The bearer has a quality attribute associated with the bearer that defines the quality of service that must be provided by the bearer.

In embodiments a suitable quality of service class for the bearer is selected based on information relating to the data to be transferred that is contained in the service request. In some embodiments, a quality of service (QoS) class identifier (QCI) that identifies the selected quality of service class is associated with a bearer as a quality attribute of the bearer.

Inside each node of the communication network, the quality of service (QoS) class identifier (QCI) associated with a bearer corresponds with more detailed pre-configured quality of service (QoS) parameters. Network nodes use the quality of service (QoS) class identifier (QCI) of a bearer as a reference, so as to determine the quality parameters that control the way in which packets from the data stream carried by that bearer are handled at the network node. Thus service requests mapped to a particular quality of service (QoS) class identifier (QCI) should receive roughly the same quality of service, independent of the serving transport network. The quality of service parameters associated with a quality of service class identifier (QCI) at a network node determine how traffic data being transported on a bearer having that quality of service class identifier (QCI) is handled. For example, the quality parameters may relate to the data rate, error rate and delay at a network node for the data being transferred by the bearer with the selected quality of service class. The quality parameters may include parameters relating to scheduling weights maximum delay, residual error rate that characterize the type of transport service provided by the virtual connection. In addition, the quality parameters may include queue management thresholds and packet drop parameters which will determine whether packets are dropped at a node if the node is congested.

In addition, a bearer has a priority attribute that is used to determine priority of bearer establishment and retention of bearers. This Allocation and Retention Priority (ARP) attribute determines the priority given to that bearer during establishment of the bearer, and also the priority to be given to the bearer during operation, for example determining whether a bearer can be dropped, or whether it can cause other bearers to be dropped, if the network gets congested. Emergency calls might be associated with a high allocation and retention priority (ARP) attribute, for example.

In response to a service request, the network can implement bearers using the transport protocols that are appropriate for the corresponding interfaces. All procedures used to manage Bearers (activate, modify, deactivate) are referred to as Session Management (SM) procedures. The user equipment UE and the mobility management entity MME of a 3 Generation Partnership Project 3GPP network communicate using a Session Management (SM ) protocol (for example as defined in 3GPP TS 24.301) in order to manipulate the bearers.

The procedure used to establish an EPS Bearer is called an EPS Bearer Activation procedure. During the EPS Bearer Activation procedure many smaller steps take place in order to establish the required virtual connection. Amongst other things, these steps may include the following: selection of edge nodes and intermediate nodes (for example, the S-GW and P- GW are selected); establishment of tunnels between the participating nodes; configuration of forwarding tables; configuration of classification rules with the new traffic flow templates; and reservation of quality of service (QoS) resources in every participating interface.

A method of ensuring preferential communication network access to emergency services during an emergency situation is provided by Enhanced Multimedia Priority Services (eMPS), which have been standardized within Long term evolution (LTE) networks, as set out in 3 GPP TS 22.153 and 3 GPP TS 23.854

The intention of the Enhanced Multimedia Priority Services (eMPS) is to enable national security/emergency preparedness (NS/EP) users, the Service Users, to initiate priority calls or multimedia sessions using a public communication network during network congestion conditions.

The Enhanced Multimedia Priority Services (eMPS) is only available to Service Users who are the government-authorized personnel, emergency management officials and/or other authorized users who need to respond to emergency situations (e.g., floods, hurricanes, earthquakes, terrorist attacks). Effective disaster response and management rely on the ability of Service Users to communicate during congestion conditions. Service Users are expected to receive priority treatment in accessing communication networks, in support of mission critical multimedia communications.

The Enhanced Multimedia Priority Services (eMPS) provide broadband IP -based multimedia services (IMS-based and non-IMS-based) over wireless networks in support of voice, video, and data services. Network support for Enhanced Multimedia Priority Services (eMPS) requires end-to-end priority treatment in call/session origination/termination including the Non Access Stratum (NAS) and Access Stratum (AS) signalling establishment procedures at originating/terminating network side as well as resource allocation in the core and radio networks for bearers. The Enhanced Multimedia Priority Services (eMPS) also requires end- to-end priority treatment in roaming situations if supported by the visiting network and if the roaming user is authorized to receive priority service. A Service User is assigned a priority level by a regional/national authority that is authorized to issue priority levels. Upon invocation of Enhanced Multimedia Priority Services (eMPS), the Service User's priority level is used to identify the priority to be used for the session being established and the communication network provides preferential access in the access and core network to signalling and media bearer related resources associated with the session. In some situations active sessions of existing bearers can be pre-empted to provide access to the communication network resources for the Service User.

In the future it is anticipated that the number of devices connected to communication networks will continue to rise, with 50 Billion connected devices expected by the year 2020. A significant demand from enterprises requiring communications between machines or communications with machines is expected to arise to take advantage of the communication capability in future communication networks in order to deliver innovative services.

Current communication networks are unable to support such services efficiently. The present invention seeks to at least alleviate the drawbacks of the prior art and to provide a new method of and apparatus for establishing bearer attributes in a communication network.

SUMMARY

In accordance with a first aspect of the invention, there is provided a method of establishing bearer attributes of a bearer in a communication network in response to a priority data transfer service request. In a first step a high access priority attribute is assigned to a bearer associated with the service request, providing preferential access to network resources for the bearer. In a second step, a priority data quality attribute is assigned to a bearer associated with the service request, providing low delay, error intolerant data transfer for the priority data transfer service. In some embodiments of the method, the step of assigning a high access priority attribute to a bearer associated with the service request comprises a first step of determining whether the priority attribute of a signalling bearer associated with the service request is a high priority attribute, and changing the priority attribute to a high priority attribute if necessary and a second step of creating a media bearer associated with the service request with a high access priority attribute providing preferential access to network resources for the media bearer.

In some embodiments, the method also includes the step of configuring bearer resources allocated to the priority data service request in accordance with the bearer attribute parameters.

In some embodiments, a preliminary step of determining whether the priority data transfer service request is authorised is carried out, and the high access priority attribute and priority data quality of service class attribute are assigned to a bearer only if the priority data transfer service request is authorised.

In some embodiments, it is determined whether the priority data transfer service is authorised by determining whether the user is authorised to access a priority data subscription service using high priority bearers. The high priority bearers in some embodiments may be made available through a priority emergency service in the communication network. In some embodiments the priority emergency service is an Enhanced Multimedia Priority Services service in a Long Term Evolution, LTE, standardised by the third Generation Partnership Project, 3 GPP.

In some embodiments the priority data transfer service request requires an at least substantially unidirectional resource allocation. In some embodiments the priority data transfer service request requires a priority data transfer having a low latency through the network together with at least substantially zero error rate. In some embodiments the quality of service class attributes established for a bearer are suitable for use in the network to determine handling of traffic being transported/transferred by the bearer, wherein data traffic is transferred with low latency and substantially error free by the or a bearer having a priority data quality of service class attribute.

In some embodiments the quality of service class attributes established for a bearer are suitable for use in the communication network to reserve network resources for the data traffic being transported/transferred by the bearer, wherein network resources are reserved in a substantially unidirectional manner for the or a bearer having a priority data quality of service class attribute.

In some embodiments the priority data quality of service class attribute assigned to the or a bearer associated with the service request corresponds to a plurality of bearer attribute parameters.

In accordance with a second aspect of the invention there is provided an apparatus operable, in use, to establish bearer attributes of a bearer in a communication network. The apparatus comprising an interface for coupling to the network to receive notification of a priority data transfer service request and further comprising a processor. The processor is operable firstly to assign a high access priority attribute to a bearer associated with the service request, providing preferential access to network resources for the bearer. The processor is operable secondly to assign a priority data quality of service class attribute to a bearer associated with the service request, providing low delay, error intolerant data transfer for the priority data transfer service.

In some embodiments, the apparatus is also operatively coupled to a priority service authorisation function in order to determine whether the priority data transfer service request is authorised. If the priority data transfer service request is authorised, the processor is operable to assign a high access priority attribute to a bearer and to assign a priority data quality of service class attribute to a bearer. In some embodiments, the apparatus is also operatively coupled with at least one network node in the communication network and the processor is operable to configure bearer resources allocated to the priority data service request in accordance with the bearer attribute parameters.

In some embodiments, the apparatus is implemented within a Policy and Charging Rules Function of a communication network standardised by the 3 Generation Partnership Project.

In accordance with a third aspect of the invention, there is provided a machine-readable medium comprising instructions which cause a processor to perform the method in accordance with embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying drawings:

Figure 1 illustrates bearers in a communication network;

Figure 2 is a schematic diagram showing elements of a communication network suitable for implementing embodiments of a method of the invention;

Figure 3 is a flow chart of a method in accordance with embodiments of the invention;

Figure 4 shows an exemplary communication network in which embodiments of the invention may be implemented; and

Figure 5 illustrates an exemplary signal flow during service initiation of a priority data service in accordance with embodiments of the invention.

DETAILED DESCRIPTION The present invention will now be described with reference to Figures 2-5.

The invention relates to the provision of connectivity within a communication network for a priority data transfer, for example in support of an additional priority data service provided via the communication network.

As will be appreciated, the provision of priority data transfer will be useful for additional priority data services in many diverse fields including the healthcare sector providing health monitoring and the financial sector providing transfer of time-critical financial information, for example share prices. In general, it would be expected that such a priority data transfer service would be provided under subscription, although it is possible to envisage priority data transfer for additional priority data services not requiring a subscription.

The priority data transfer will typically be a machine to machine priority data transfer, although embodiments in which a person is sending or receiving the priority data transfer are not excluded.

In order to better understand the invention, one example of a scenario in which the present invention may be used machine to machine priority data transfer will now be discussed in more detail. In the exemplary scenario a remote health management or monitoring service is provided in which a patient is monitored by a device such as a heart pacemaker or an asthma monitor. In the event of deterioration in the health of the patient being monitored below a threshold, which is detected by the heart monitor or asthma monitor, for example, a report is sent by an associated communication device to the health management service. The health management service can then initiate an appropriate response service, for example by arranging medical assistance to be sent to the patient.

There are 3 entities involved in the operation of an additional priority data service such as the exemplary remote health management or monitoring service, The first entity is the enterprise owner that is providing the additional priority data service. In this exemplary scenario, this entity might be a company providing the health management or monitoring service to the patient.

The second entity is the operator of the communication network that provides connectivity for the priority data transfers across the communication network in support of the additional priority data service provided by the enterprise owner. The network operator will have a service level agreement (SLA) with the enterprise owner, which typically will be realized via an appropriate subscription that the network operator can provide. This subscription, among other parameters, will have an associated End-to-End Quality of service (QoS) requirement for the priority data transfers associated with the additional priority data service.

The third entity is the user. From the perspective of the health management company, the user entity is the patient. From the perspective of the network operator, the user entity is the communication device connected to the communication network.

Priority data transfers for machine to machine (M2M) services, such as the exemplary health monitoring service, are likely to be characterized by at least some of the following characteristics: unidirectional resource allocation for one way data transfer, generally from the user entity to the service entity, although the degree of symmetry may be one way or two way with a default of one-way; resource release following data transfer; low delay; low latency and minimal or no information loss.

The following is a summary of the characteristics of exemplary requirements for the priority data transfer. Medium Application Degree of Data rate Key performance parameters and symmetry target values

High Priority, End-to- Delay Information

Low Delay, end Oneloss

Error way Variation

Intolerant within a

M2M Delay call

Enterprise

Data Telemetry Primarily, <28.8 kb/s < 250 N.A

One-way msec

Zero

As discussed above, the classification of the quality of service (QoS) associated with a particular service request is determined by the data type information associated with the service request. For example in communication networks such as the Long Term Evolution (LTE) communication network under standardization by the 3 Generation Partnership project, as set out in 3GPP TS 23.107 and 3GPP TS 22.105, a service request for service in a communication network is mapped to one of the following quality of service (QoS) classes: Conversational; Streaming; Interactive; and Background. These traffic classes do not efficiently support a priority data transfer of the type envisaged to support this new type of priority data transfer service.

Some factors that can be used to distinguish between the standard defined quality of service (QoS) classes for carrying traffic flows are: whether or not the traffic flows are real time traffic flows; how delay sensitive the traffic flow is; and control of error rate.

The conversational quality of service (QoS) class and the streaming quality of service (QoS) class are mainly intended to be used to carry real-time traffic flows. The main difference between them is how delay sensitive the traffic is. Conversational class is intended to be used for traffic which is very delay sensitive. The conversational traffic class is based on the principle that human interaction is involved. The existing conversational traffic class therefore provides bidirectional resource allocation and assumes a two way data transfer, and that at some point in the future the resources will be released. Interactive class and Background class are mainly meant to be used by traditional Internet applications like WWW, Email, Telnet, FTP and News. Due to looser delay requirements, compared with conversational and streaming classes, both the Interactive class and

Background class provide better error rate by means of channel coding and retransmission.

The main difference between Interactive and Background class is that Interactive class is mainly used by interactive applications, e.g. interactive Email or interactive Web browsing, while Background class is meant for background traffic, e.g. background download of Emails or background file downloading. Responsiveness of the interactive applications is ensured by separating interactive and background applications and giving traffic in the Interactive class a higher scheduling priority than traffic in the background class. However, the actual bearer quality will depend on the load of the network and the admission control policy of the network operator.

Background applications use transmission resources only when interactive applications do not need them. This is very important in wireless environment where the bandwidth is low compared to fixed networks. The background class is optimised for machine-to-machine communication that is not delay sensitive, such as messaging services. Background applications tolerate a higher delay than applications using the interactive class, which is the main difference between the background and interactive classes.

The use of a bearer with a conversational traffic class to support time critical machine to machine (M2M) services would be very inefficient in terms of network resource utilization.

The use of a bearer with an Interactive or Background traffic class would not meet the transfer delay requirement associated with the business need. Therefore in accordance with embodiments of the invention a new "Priority Data" traffic class is proposed that supports the requirements of the new End-to-End priority service.

The parameters of the new priority data traffic class are set out below, along with those of the conversational traffic class, the streaming traffic class, the interactive traffic class and the background traffic class for comparison.

There is also the need to consider the network behaviour during busy hour, peak traffic period and consequences of network congestion in terms of meeting the end-to-end requirements of the associated service request and associated service level agreement (SLA) between the enterprise owner, in this case the health management company, and connectivity provider, in this case the communication network operator.

Therefore in embodiments of the invention the end-to-end priority services are provided using high priority bearers. In some embodiments this may be achieved by making an emergency communication service such as the Enhanced Multimedia Priority Services (eMPS) available to private enterprise, and therefore to the public. Thus the public is able to use high priority bearers of an emergency communication service in communication network to achieve a priority data transfer for an additional priority data service. In some

embodiments, the priority data service is accessed by the user under subscription control, and therefore access to the high priority bearers is provided under subscription control.

Thus in some embodiments a priority is assigned to bearers established for the priority data transfer that is a higher priority than the priority assigned to bearers established for a conventional data transfer. In some embodiments the use of Enhanced Multimedia Priority Services (eMPS) enables the bearers to be established for priority data transfer at a priority comparable to the priority of an emergency call.

A method in accordance with an exemplary embodiment of the invention will now be described with reference to Figure 2 and 3.

Figure 2 is a schematic diagram showing elements of a communication network relevant to the invention that are suitable for implementing embodiments of the method of the invention.

In the exemplary embodiment the priority data transfer is described in the context of a health monitoring system. However, the invention may also be used in other situations in which priority data transfer over the communication network is required, for example for the provision of other additional priority data services including machine to machine services in a communication network. Figure 3 is a flow chart of the method in accordance with embodiments of the invention.

In Figure 2 a communication network 40 is provided for supplying communication services to user equipment UE 42. The user equipment is arranged to communicate priority data over the communication network. In the exemplary embodiment, the user equipment is, or is associated with, a health monitoring device, such as a pacemaker monitor and is arranged to communicate priority data over the communication network in response to a monitored event, such as a heart attack.

The communication network 40 has at least one gateway 44 enabling the user equipment UE 42 access to other communication networks.

A service target 46 to which the high priority data is to be transferred via the communication network is shown. The service target 46 provides a high priority machine to machine service, for example service target 46 receives high priority health information from the user equipment UE 42 in order to provide the health monitoring service of the exemplary embodiment.

Health information as exemplary high priority data is communicated from the user equipment UE 42 to the service target 46 in the event of a monitored health event by way of bearers 48a and 48b in the communication network 40 between the user equipment UE and the gateway 44, and at least one external bearer 50 set up between the gateway 44 and the service target 46. The setting up of suitable external bearers and the operation of the service target 46 are not relevant to the operation of embodiments of the invention, and will not be discussed in further detail. In the exemplary embodiment as will be explained in more detail hereafter, the bearer 48a is a signalling bearer, and bearer 48b is a traffic bearer for example as defined in the 3 GPP Long Term Evolution (LTE) specification and only a single traffic bearer 48a is shown. However, the invention may be implemented in other ways as will be understood by a skilled person, and the invention is not limited to the embodiments shown.

The communication network is also provided with a policy function 60. The policy function 60 is coupled to a priority service authorization function 62. The priority service

authorization function 62 is able to determine whether user equipment 42 is authorized to access a priority service in the communication network for a priority data transfer in connection with the priority data transfer service. In some embodiments, the priority service authorization function 62 is coupled to the service target 46 in order to receive priority service authorization information 64.

The policy function 60 is arranged to receive a priority data transfer service initiation notification 66 indicating that a priority data transfer using high priority bearers in the communication network has been requested. The policy function 60 is operable to establish bearer attributes for bearers in a communication network and is arranged to output policy function allocations of bearer attributes 68 namely the allocation of a high priority to bearers 48a and 48b, and an allocation of a priority data quality of service class to the traffic bearer 48b.

The method of operation of the policy function 60 in establishing bearer attributes for bearers in a communication network in accordance with one embodiment will now be described with reference to Figure 3.

This method is used to set up bearers 48a, 48b in the communication network 40 in response to a service request from the user equipment 42. Therefore, in the exemplary embodiment in which the service being provided is a health monitoring service, a monitoring event requiring notification to the service target 46 may occur. In response to the detection of the monitored event, the user equipment will send a service request that requests the communication network to provide communication services in support of the priority data transfer service. This request reaches the policy function 60 as the priority subscription service initiation notification 66.

In response to the receipt of the priority subscription service initiation notification 66 the policy function 60 implements the method of determining bearer attributes in a

communication network in accordance with embodiments of the invention in order to establish suitable attributes for bearers 48b for the communication between the user equipment UE 42 and the service target 46.

Thus in the first step 70 shown in Figure 3 there is a service request for establishment of a priority communication service. Since this step is not taken by the policy function 60, this step is shown in dashed lines.

In step 72, it is determined whether the user is authorized to access priority data transfer service using high priority bearers. In the exemplary embodiment, the priority data transfer is provided by the communication network under subscription control. However, in

embodiments in which access to a priority data transfer is available without authorisation, this step can be omitted, and is therefore shown in dashed lines.

In the exemplary embodiment shown in Figure 2, the policy function carries out step 72 of the method by accessing priority data transfer service authorization information from the priority data transfer service authorization function 62.

In the exemplary embodiment the priority communication service is provided by making use of the existing Enhanced Multimedia Priority Services (eMPS) under subscription control. If the user equipment UE 42 is not authorized for a priority data transfer service, step 72-n, the request for priority data transfer service is declined, and the method ends step 74.

If the user equipment UE 42 is authorized for a priority data transfer service, step 72-y, the policy function 60 establishes the attributes 68 for at least the traffic bearer 48b to provide the priority subscription service.

In particular, in step 76 the policy function 60 designates the bearers as high priority bearers. In particular, the policy function 60 allocates a priority attribute of the bearer to be a high priority, so that in network congestion conditions the reservation of communication resources for bearer 48 takes precedence over the reservation of communication resources for other bearers in the communication network. In the exemplary embodiment this is achieved by the selection of a high priority value for the allocation and retention priority (ARP) attribute of the bearer 48b in a long term evolution (LTE) network. In some embodiments, the high priority value for a bearer for a priority data transfer may be of equivalent priority to the priority value for a bearer for an emergency service user: in other embodiments the priority given to the bearer for the priority data transfer may be less than that of the emergency service user, but will still be a higher priority than standard bearers in the communication network.

In addition, in step 78, the policy function 60 assigns a priority data quality of service class providing low delay, error intolerant data transfer for the priority communication service to bearers associated with the service request.

Once the attributes of the bearers for the priority data transfer service request have been assigned in steps 76 and 78, the network resources for the bearers may be configured, in step 80. As will be apparent to a skilled person, embodiments of the invention may be implemented in different communication networks as selected by a skilled person. An embodiment of the invention implemented in a Long Term Evolution (LTE) network in which priority bearers are established using the Enhanced Multimedia Priority Services (eMPS) under subscription control will now be described with reference to Figures 4 and 5.

The policy function 60 comprises an interface 152 for coupling to the network to receive notification of a priority data transfer service (e.g. medical reporting service) request. The policy function 60 further comprises a processor 150. The processor 150 being operable to assign a high access priority attribute to a bearer associated with the service request and also operable to assign a priority data quality of service class attribute to a bearer associated with the service request.

Preferably, in order determine whether the priority data transfer service request is authorised the policy function 60 is also operatively coupled via the interface 152 to a priority service authorisation function 62. The processor 150 is operable to assign a high access priority attribute to a bearer and to assign a priority data quality of service class attribute to a bearer only if the priority data transfer service request is authorised. In another preferred

embodiment the policy function 60 is operatively coupled via the interface 152 to at least one network node in the communication network and the processor 150 is configures bearer resources allocated to the priority data service request in accordance with the bearer attribute parameters.

Figure 4 shows an exemplary communication network 90 in which embodiments of the invention may be implemented. The exemplary communication network 90 is a Systems Architecture Evolution (SAE) network that forms the core network architecture of the long term evolution (LTE) communication standard, as will be familiar to a skilled person.

Therefore the operation of the network that is not relevant to embodiments of the invention will not be described in further detail. It will be apparent to a skilled person that embodiments of the invention may be implemented in other communication networks. The communication network 90 provides communication services to the user equipment UE 92 and enables the user equipment UE 92 to access an external network 94. As will be known to a skilled person, the communication network 90 has an eNodeB 96 that communicates with the user equipment UE 92 over a radio interface. The eNodeB 96 is coupled to a serving gateway SGW 98, which routes and forwards user data packets and manages and stores user equipment contexts, for example parameters for the IP bearer service. The serving gateway SGW 98 is in turn coupled with a packet data network (PDN) gateway PGW 100. The packet data network (PDN) gateway PGW 100 provides connectivity from the user equipment UE 92 to the external network 94 by providing a point of entry and exit for traffic data to and from the user equipment UE 92.

The communication network 90 is also provided with a mobility management entity MME 102. The mobility management entity MME 102 is involved in the bearer

activation/deactivation process. In addition the communication network 90 also has a policy and charging rules function PCRF 104. In the exemplary embodiment, the policy and charging rules function PCRF 104 implements the policy function 60 which has previously been described with reference to Figure 2.

Figure 5 illustrates an exemplary signal flow within the communication network shown in Figure 4 during service initiation of a priority data service in accordance with embodiments of the invention. This signal flow broadly corresponds with the signal flow used during the establishment of bearers for the existing Enhanced Multimedia Priority Services (eMPS) described in 3GPP TS 23.854 However, details of the signal flow that are less relevant to the present invention have been amalgamated or omitted, as the skilled person will understand.

In a first step 110, radio resource control (RRC) for the user equipment UE 92 is established, if necessary. If the UE 92 is in EMM-CONNECTED state, this step is not required. The user equipment UE 92 sends a service request in order to initiate the priority data transfer for the priority event. The Service User associated with the user equipment UE 92 has an access class in the range of 11-15, the Establishment Cause in the radio resource control (RRC) connection request is set to highPriority Access. When the mobility management entity MME 102 receives service request signalling with an establishment cause set to

highPriority Access from the user equipment 92, the mobility management entity MME 102 and eNodeB 96 prioritize radio resource control (RRC) connection requests and establish the SI bearer and radio resources with priority.

In a second step 112, the user equipment UE 92 sends a SIP INVITE message on a pre-established default or dedicated EPS bearer used to transport IMS/SIP signalling. This EPS bearer corresponds with the signalling bearer 48a shown in Figure 2. The Enhanced Multimedia Priority Services (eMPS) code/identifier and destination address or the Enhanced Multimedia Priority Services (eMPS) input string supplied by the Service User is the SIP message, as will be known by the skilled person.

In a third step 114, the Policy and Charging Rules function PCRF 104 carries out an authorisation function to determine whether the user equipment 92 is authorised to make a priority data transfer. In this exemplary embodiment the Enhanced Multimedia Priority Services (eMPS) is being used to provide the priority communication service providing access to high priority bearers. Therefore, in step 114 the Policy and Charging Rules function PCRF 104 carries out a Service User Authorization and Enhanced Multimedia Priority Services (eMPS) subscription identification.

In embodiments of the invention, the Policy and Charging Rules function PCRF 104 determines whether the user equipment 92 is authorised to access Enhanced Multimedia Priority Services (eMPS) services under subscription or third party control, as described above with reference to Figure 2. In embodiments of the invention the Policy and Charging Rules function PCRF 104 acts in the same manner as the policy function 60 described above with reference to Figure 2. The priority subscription service authorisation function 62 described above with reference to Figure 2 may be implemented as part of the Policy and Charging Rules function PCRF 104 in some embodiments or in other ways, as will be appreciated by a skilled person.

When the Policy and Charging Rules function PCRF 104 recognizes that the service request is associated with a valid Enhanced Multimedia Priority Services (eMPS) session and should be given priority treatment, the Policy and Charging Rules function PCRF 104 stores the received session information and identifies the affected IP-Connectivity Access Network (IP CAN) session.

In step 116, the Policy and Charging Rules function PCRF 104 checks if the allocation and retention priority (ARP) of the EPS signalling bearer (default or dedicated) is used to transport IMS/SIP signalling has a high priority value appropriate for the Enhanced

Multimedia Priority Services (eMPS) session.

If the Allocation and Retention Priority (ARP) value of the EPS bearer that is used to transport IMS/SIP signalling is not appropriate for the Enhanced Multimedia Priority Services (eMPS) session, the Policy and Charging Rules function PCRF 104 modifies the Allocation and Retention priority (ARP) value of the EPS bearer that is used to transport IMS/SIP signalling to a high priority value, in this case to a value appropriate for the Enhanced Multimedia Priority Services (eMPS) session.

If the IMS/SIP signalling traffic is transported over a dedicated EPS bearer, then the Policy and Charging Rules function PCRF 104 modifies the allocation and retention priority (ARP) value of the default EPS bearer of the same packet data network PDN connection to ensure the IP multimedia sub-system (IMS) signalling transported over a dedicated EPS bearer and default EPS bearer have an allocation and retention priority (ARP) value appropriate for Enhanced Multimedia Priority Services (eMPS) service, in order to avoid being released due to congestion. In this manner, the Policy and Charging Rules function PCRF 104 is able to assign a high access priority attribute to the EPS bearer. Finally, in step 118, the Policy and Charging Rules function PCRF 104 initiates the establishment of dedicated EPS bearer(s) to transport the media traffic for the high priority data transfer session. This bearer corresponds with the traffic bearer 48b described above with reference to Figure 2.

This bearer that is established in step 118 for the priority data transfer is assigned a high access priority attribute and the EPS bearer in the exemplary embodiment is therefore created with a high priority allocation and retention priority (ARP) value. The dedicated EPS media bearer is therefore handled with priority in the evolved packet system (EPS).

The bearer that is established in step 118 or the priority data transfer is assigned a priority data quality of service class. The priority data traffic class is selected to support the End-to- End Quality of service (QoS) requirement of the service user and associated subscription.

In yet another embodiment a machine-readable medium is disclosed. The machine readable medium comprises instructions which cause a processor to perform a method of establishing bearer attributes of a bearer in a communication network in response to a priority data transfer service request. Once executed on the processor the method comprises the steps illustrated in Fig. 3 and discussed above.

Thus as will be appreciated by a skilled person, a novel method of and apparatus for establishing bearer attributes is disclosed that provides a new Quality of service (QoS) offering in mobility solutions that will stimulate enterprise evolution and growth.

Claims

1. A method of establishing bearer attributes of a bearer in a communication network in response to a priority data transfer service request, comprising the steps of: assigning a high access priority attribute to a bearer associated with the service request, providing preferential access to network resources for the bearer; and assigning a priority data quality attribute to a bearer associated with the service request, providing low delay, error intolerant data transfer for the priority data transfer service.

2. The method as claimed in claim 1 wherein the step of assigning a high access priority attribute to a bearer associated with the service request comprises the steps of: determining whether the priority attribute of a signalling bearer associated with the service request is a high priority attribute, and changing the priority attribute to a high priority attribute if necessary; and creating a media bearer associated with the service request with a high access priority attribute providing preferential access to network resources for the media bearer.

3. The method as claimed in claim 1 or 2, wherein the method also comprises the step of: configuring bearer resources allocated to the priority data service request in accordance with the bearer attribute parameters.

4. The method as claimed in one of claims 1-3 further comprising the preliminary step of: determining whether the priority data transfer service request is authorised, wherein the step of assigning a high access priority attribute and the step of assigning a priority data quality of service class attribute are carried out only if the priority data transfer service request is authorised.

5. The method as claimed in claim 4 wherein the step of determining whether the

priority data transfer service is authorised comprises determining whether the user is authorised to access a priority data subscription service using high priority bearers.

6. The method as claimed in claim 5 wherein the step of determining whether the

priority data transfer service request is authorised comprises the step of determining whether a user is authorised to access a priority data subscription service using high priority bearers of a priority emergency service in the communication network.

7. The method as claimed in claim 6 where the priority emergency service is an

Enhanced Multimedia Priority Services service in a Long Term Evolution, LTE, standardised by the third Generation Partnership Project, 3GPP.

8. The method as claimed in any preceding claim wherein the priority data transfer service request requires an at least substantially unidirectional resource allocation.

9. The method as claimed in any preceding claim wherein the priority data transfer service request requires a priority data transfer having a low latency through the network together with at least substantially zero error rate.

10. The method as claimed in any preceding claim, in which quality of service class attributes established for a bearer are suitable for use in the network to determine handling of traffic being transported by the bearer, wherein data traffic is transported with low latency and substantially error free by the or a bearer having a priority data quality of service class attribute.

11. The method as claimed in any preceding claim, in which quality of service class

attributes established for a bearer are suitable for use in the communication network to reserve network resources for the data traffic being transported by the bearer, wherein network resources are reserved in a substantially unidirectional manner for the or a bearer having a priority data quality of service class attribute.

12. The method as claimed in any preceding claim wherein the priority data quality of service class attribute assigned to the or a bearer associated with the service request corresponds to a plurality of bearer attribute parameters.

13. An apparatus operable, in use, to establish bearer attributes of a bearer in a

communication network, the apparatus comprising an interface for coupling to the network to receive notification of a priority data transfer service request, the apparatus further comprising a processor, the processor being operable to assign a high access priority attribute to a bearer associated with the service request, providing preferential access to network resources for the bearer; and the processor being operable to assign a priority data quality of service class attribute to a bearer associated with the service request, providing low delay, error intolerant data transfer for the priority data transfer service.

14. The apparatus as claimed in claim 13, wherein the apparatus is also operatively

coupled to a priority service authorisation function in order to determine whether the priority data transfer service request is authorised, wherein the processor is operable to assign a high access priority attribute to a bearer and to assign a priority data quality of service class attribute to a bearer only if the priority data transfer service request is authorised.

15. The apparatus as claimed in claim 13, wherein the apparatus is also operatively

coupled with at least one network node in the communication network and the processor is operable to configure bearer resources allocated to the priority data service request in accordance with the bearer attribute parameters.

16. The apparatus as claimed in one of claims 13-15 implemented within a Policy and Charging Rules Function of a communication network standardised by the 3

Generation Partnership Project.

17. A machine-readable medium comprising instructions which cause a processor to perform a method of establishing bearer attributes of a bearer in a communication network in response to a priority data transfer service request, the method comprising the steps of: assigning a high access priority attribute to a bearer associated with the service request, providing preferential access to network resources for the bearer; and assigning a priority data quality attribute to a bearer associated with the service request, providing low delay, error intolerant data transfer for the priority data transfer service.