WO2014090341A1

WO2014090341A1 - Exchange of load notifications between neighbouring nodes of networks using different communication technologies for balancing their loads by transferring user devices

Info

Publication number: WO2014090341A1
Application number: PCT/EP2012/075636
Authority: WO
Inventors: Patrick Maguire
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2012-12-14
Filing date: 2012-12-14
Publication date: 2014-06-19

Abstract

Embodiments of the invention described herein provide methods and apparatuses for exchanging load indications between neighbouring network nodes using different communication technologies, thereby enabling the transfer of traffic load from a communication network, such as a LTE network, to a lower power per user node, such as a wireless local area network (WLAN) node, based on the availability of capacity at the lower power per user node. In embodiments of the invention handover or cell re-selection algorithms are able preemptively to trigger a handover or a cell re-selection based on the availability of capacity at the lower power node so as to reduce overall power consumption for the operators' network.

Description

EXCHANGE OF LOAD NOTIFICATIONS BETWEEN NEIGHBOURING NODES OF

NETWORKS USING DIFFERENT COMMUNICATION TECHNOLOGIES FOR BALANCING THEIR LOADS BY TRANSFERRING USER DEVICES

TECHNICAL FIELD

The present invention relates to a method in, and apparatus for, a communication node. Embodiments of the invention may improve power management in a communication network. In particular, embodiments of the invention relate to the communication of capacity information between nodes providing communication services to user devices.

BACKGROUND

Increasingly the power consumption of communication networks is becoming a significant factor in the operational expenditure (OPEX) associated with a

communication network. For example it is thought that in some countries

communication networks may each consume up to 1% of the total energy consumption of the country.

It is well known that that the energy efficiency of a cell in providing communication services to a user device varies depending upon a number of factors such as the size of the cell, the population density and the number of subscribers. As a rule of thumb, the smaller the cell the more power efficient the cell is on a per user basis. In particular small indoor cells are able to operate with a lower transmit power compared with macrocells because the radio signal originates within a matter of meters from the user device. In addition, the user device and communications node are both indoors, so radio frequency (RF) signal energy is not expended in penetrating the outer wall of a building, resulting in lower radio frequency RF power consumption.

Since small cells use less radio frequency (RF) power per user than macrocells, in most cases small cells also require significantly less power per user. For example, the average macrocell uses around 1000W of energy to serve around 120 simultaneous users (an average of 8.33W/user); in comparison, an enterprise femtocell might require 50W of power for 32 simultaneous users (an average of 1.56 W/user); and a consumer femtocell typically and more efficiently requires 8W of power and accommodates around 8 users (an average of 1 W/user). In the future it is envisaged that capacity demands in communication networks will continue to increase. As a result it is expected that the power consumption of the communication network will increasingly be a significant factor in the operational expenditure (OPEX) for the communication network operator.

To address growing demands for increased capacity, it is anticipated that operators will use small cells coupled with their macrocell/picocell deployment to handle excess load in the macrocell/picocell deployment in a cost effective manner. Small cells also have the potential to reduce the transmit power required for serving a user by a factor in the order of 10³ compared with a macrocell/picocell deployment.

Small cells may employ wireless local area network (WLAN) technologies, for example using the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standards, which are commonly referred to as Wi-Fi. It is therefore expected that small cells employing wireless local area network (WLAN) technologies will be deployed by network operators alongside a wide area cellular communication network, such as a Long Term Evolution (LTE) network currently being deployed. In this situation, the Wi-Fi nodes (the Wi-Fi access points (AP) or Wi-Fi access Controllers (AC)) may be integrated with a macrocell node or a picocell node of the wide area cellular

communication network or may be stand alone nodes.

Normally, when a Wi-Fi access point (AP) has a client with a slower connection, all other clients are throttled down to that same rate. A Rate Aware Fairness process overcomes this issue by trying to give clients equal amounts of air-time instead of equal numbers of packets. Rate aware fairness is a transmission algorithm that chooses dynamic retreat and progress thresholds based on the transmission rate of the station being transmitted to, and the size of the packet.

A typical admission control arrangement for a wireless local area network (WLAN) cell allows the maximum number of associated clients per radio channel to be configured. If the number of associated clients exceeds the configured value, new clients are not allowed to connect to the small cell. The limitation in the number of associated clients has the effect of reducing the number of collisions and limiting the total traffic load offered, and of forcing traffic to be distributed over different access point (AP) operating on different radio channels.

In Long Term Evolution (LTE) communication networks, Down Link Transmit Carrier power is one of the parameters used by the Admission control functions to determine if a user is granted access to a cell or not. The greater the capacity requirements, the greater the Down Link Transmit Carrier power must be in order to support a user request and it is likely that a radio node of the Long Term Evolution (LTE) network requires a relatively high transmit power to support a user access. If it is assumed that the macro cell/pico cell Long Term Evolution (LTE) communication network is efficiently dimensioned, generally it is expected that the capacity limit at which load is transferred to a small cell would be reached relatively infrequently.

SUMMARY

The present invention seeks to alleviate at least some of the problems in the prior art. Embodiments of the invention seek to support a growth in network capacity in a cost efficient manner by operating so as to reduce the operational expenditure (OPEX) compared with a prior art communication network. In accordance with an aspect of the invention there is provided a method in a node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology. In a first step a subscription is made to load notifications indicating available load capacity at a neighbour node that is adapted to provide, in use, communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology. In a second step load notifications are received from the neighbor node.

In some embodiments, the receipt of a load notification indicates that the neighbour node is able to accept a user device transfer from a communication network node.

In some embodiments a transfer of one or more user devices attached to the network node of the communication network to the neighbour node is determined in response to the load notification. In some embodiments the determination to transfer user devices to the neighbour node is made in response to the receipt of one or more load notifications. In some embodiments the receipt of a load notification indicating a high load capacity at the neighbour node increases the likelihood that transfer of one or more user devices from the network node to the neighbour node is determined.

In some embodiments the method also includes the step of instructing a user device to transfer to the neighbour node.

In some embodiments in an operation and maintenance node of the communication network, in a third step at least one load notification threshold for the neighbour node is determined using received load notifications. In a fourth step at least one load threshold is configured at the neighbour node.

In some embodiments a subscription to a congestion notification indicating congestion at the neighbour node is made. Congestion notifications from the neighbour node are then received at the operation and maintenance node of the communication network.

In some embodiments in a manual operation mode of the operation and maintenance node, at least one load notification threshold is determined using information from at least one congestion notification. In some embodiments in a manual operation mode neighbour node congestion notifications received at the operation and maintenance, O&M, node are monitored to determine whether the neighbour node is congested. When the neighbour node is not congested the neighbour node is configured in an automatic operation mode in which the neighbour node determines at least one load notification threshold.

In some embodiments in an automatic operation mode the neighbour node congestion notifications received at the operation and maintenance, O&M, node are monitored to determine whether the neighbour node is congested. The neighbour node is configured by the operation and maintenance, O&M, node in a manual operation mode in response to the receipt of congestion notifications from the neighbour node.

In accordance with an aspect of the invention there is provided a method in a neighbour node adapted to provide, in use, a communication service to a user device using a first communication technology. In a first step a request for subscription of a network node to load notifications indicating available load capacity at the neighbour node is received, the network node belonging to a communication network using a second communication technology to provide a communication service to a user device that has a higher average power per user device than the first communication technology. In a second step load notifications are sent to network nodes for which a subscription request has been received.

In some embodiments a current load of the neighbor node is compared with at least one load notification threshold to determine whether load notifications are to be sent. When the current load is less than the load notification threshold, a load notification is sent to network nodes for which a subscription request has been received.

In some embodiments the load notification threshold is set at a level at which load notifications are sent to network nodes for which a subscription request has been received when the results of the comparison indicates that the neighbour node is able to accept a user device transfer from a communication network node.

In some embodiments a set of subscribed network nodes is maintained by updating the set of subscribed network nodes to include a network node in response to the step of receiving a subscription request for load notification to that network node. The load notification is sent to subscribed network nodes.

In some embodiments, a current traffic load is obtained.

In some embodiments the current traffic load is compared with a load notification threshold after an interval defined by a periodicity parameter. In some embodiments at least one load threshold is received from a network node of the communication network and at least one load threshold parameter is configured.

In some embodiments, in an automatic mode a neighbor node subscribes to internal congestion notifications and to internal load notifications. The neighbour node determines at least one load notification threshold using traffic load notifications and congestion notifications. A least one load threshold parameter is configured.

In some embodiments it is determined whether a mode configuration update has been received from the network node of the communication network. In response to a positive determination, a neighbour node mode parameter is reconfigured in accordance with the received mode configuration update.

In some embodiments the communication technology used by the neighbour node to provide communication services to user devices is a shorter range communication technology compared with the communication technology used in the communication network to provide communication services to user devices.

In some embodiments the neighbour node operates a wireless local area network (WLAN).

In some embodiments the communication network is a cellular communication network. In accordance with an aspect of the invention there is provided machine-readable medium comprising instructions which cause a processor to perform a method in a node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology. In a first step a subscription is made to load notifications indicating available load capacity at a neighbour node that is adapted to provide, in use, communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology. In a second step load notifications are received from the neighbor node. In accordance with an aspect of the invention there is provided machine-readable medium comprising instructions which cause a processor to perform a method in a node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology. In a first step the node of a communication network subscribes to load notifications indicating available load capacity at a neighbour node that is adapted to provide, in use, communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology. In a second step load notifications are received from a neighbour node. In a third step at least one load notification threshold for the neighbour node is determined using received load notifications.

In accordance with an aspect of the invention there is provided machine-readable medium comprising instructions which cause a processor to perform a method in a neighbour node adapted to provide, in use, a communication service to a user device using a first communication technology. In a first step the neighbor node receives a request for subscription of a network node to load notifications indicating available load capacity at the neighbour node, the network node belonging to a communication network using a second communication technology to provide a communication service to a user device that has a higher average power per user device than the first communication technology. In a second step the neighbor node sends load notifications to network nodes for which a subscription request has been received.

In accordance with a further aspect of the invention there is provided apparatus for a network node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology. The apparatus comprises a first management element, adapted to communicate with a second management element in a neighbour node providing communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology, The first management element is adapted to subscribe to load notifications indicating available load capacity at the neighbour node and to receive load notifications from the second management element. In addition, the apparatus comprises a transfer element, coupled to the first management element to receive load notification data from the load notifications, and adapted to determine a transfer of one or more user devices attached to the network node to the neighbour node in response to the load notification data.

In accordance with a further aspect of the invention there is provided apparatus for an operations and maintenance node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology. The apparatus comprises a third management element, adapted to communicate with a second management element in a neighbour node providing communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology. The third management element is adapted to subscribe to load notifications from the second management element indicating available load capacity at the neighbour node and to receive load notifications from the second management element. The third management element is adapted to determine at least one load notification threshold for the neighbour node using the received load notifications; and to configure the at least one load threshold at the neighbour node.

In some embodiments the apparatus also comprises a load notification store, coupled to the third management element for storing load notification data from the load notifications for use by the third management element in determining at least one notification threshold for the neighbor node.

In some embodiments the apparatus also comprises a congestion notification store coupled to the third management element for storing neighbor node congestion data, for use by the third management element in determining at least one notification threshold for the neighbor node.

In some embodiments the apparatus also comprises a parameter record containing a load threshold parameter record for the neighbor node, wherein the second management element is coupled to the parameter record to update the load threshold parameter record for the neighbor node.

In some embodiments the apparatus also comprises a parameter record containing a mode parameter defining a mode of operation of the neighbor node. In a further aspect of the invention, there is provided apparatus for a neighbour node adapted to provide, in use, a communication service to a user device using a second communication technology. The apparatus has a subscription list for storing a set of subscribed network nodes for which a subscription request has been received. The apparatus has a load information element operable to determine a current load experienced by the neighbor node. The apparatus has a parameter set containing a load threshold parameter. The apparatus has a second management element, adapted to communicate with a first management element in a network node belonging to a communication network using a first communication technology to provide a communication service to a user device that has a higher average power per user device than the second communication technology. The second management element is coupled to the subscription list to update the set of subscribed network nodes in response to a request for subscription of a network node to load notifications indicating available load capacity at the neighbour node. The second management element is coupled to the load information element and to the parameter set and is arranged to compare the current load experienced by the neighbour node and a load threshold parameter and to send load notifications to network nodes in the subscription list when the current load is less than the load notification threshold.

In some embodiments the parameter set also contains a mode parameter determining a mode of operation of the neighbor node, the second management element being arranged to update the mode parameter in response to a message from a third management element in an operation and maintenance network node.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figure 1 is a schematic diagram showing an exemplary arrangement in which embodiments of the invention may be implemented;

Figure 2 is a flowchart showing steps of a method carried out by the nodes in a communication network in an exemplary embodiment of the invention;

Figure 3 is a flow chart showing steps of a method carried out in the neighbour nodes; Figure 4 is a flow chart showing steps of a method carried out in the neighbor node in embodiments of the invention;

Figure 5 is a flow chart showing steps of a method carried out in the

communication network nodes;

Figure 6 is a flow chart showing steps of one method carried out by an operation and maintenance node;

Figure 7 is a flow chart showing the steps in a second method carried out by the operation and maintenance node;

Figure 8 is a flow chart showing the steps in a method carried out by a neighbor node;

Figure 9 is a schematic block diagram showing the neighbor node and the network node in more detail;

Figure 10 is a schematic block diagram showing the neighbor node and the operation and maintenance node in a manual mode in more detail; and

Figure 11 is a schematic block diagram showing the neighbor node and the operation and maintenance node in an automatic mode in more detail.

DETAILED DESCRIPTION

In accordance with embodiments of the invention, a communication network is provided that provides communication services to user devices. The communication network is typically a wide area cellular communication network. In the exemplary embodiments of the present invention, the communication network is a Long Term Evolution (LTE) network. In addition, neighbor nodes that provide communication services to user devices using a communication technology that is different from, and employs a lower power per user than, the communication technology used by the communication network. The neighbor node is typically a local area network node, for example a node providing wireless local area network services. In the exemplary embodiments described in the present invention the neighbor node is a Wi-Fi node.

The neighbor nodes communicate load notifications indicating load capacity at the neighbor node to nodes of the communication network. This communication may be done periodically and/or on demand, as selected by a skilled person. Configurable parameters may be defined which determine a threshold for triggering this sharing of information. In some modes of operation, a threshold may be determined periodically at the neighbor node. In other modes of operation, a threshold may be determined by a node of the communication network, for example an operation and maintenance (O&M) node.

When the communication network node is a communication node, such as an eNodeB of a Long Term Evolution (LTE) network, the communication node may use the information about load capacity availability at the neighbor node to determine a transfer of a user device attached to the communication node to the neighbor node.

In this description, it should be understood that the term "transfer" is intended to apply both to a handover of an active user device from the communication node to the neighbour node and to a cell re-selection for a user device that is attached to the communication node but is not active at that time. Handover and cell re-selection protocols will be familiar to a skilled person, and as the details are not relevant to the invention, the hand-over and cell re-selection protocols will not be discussed in any detail. Thus when the neighbor node signals that the neighbor node has available capacity, the communication network node can transfer user devices to the neighbor node, where the user device can be provided with communication services at a lower average power per user. This will enable the network operator to reduce average power consumption per user.

This approach taken in embodiments of the invention is a change in current paradigm from:

/ (macro/pico node) have very limited capacity now, here is some load

To:

/ (small cell node) have available capacity; give me load if you wish to save power The communication network node may be an operation and maintenance (O&M) node. The operation and maintenance (O&M) node uses the information about load capacity at the neighbor node to determine notification thresholds for the neighbour node. In embodiments of the invention, a management element is provided in a node in a communication network, and also in a neighbour node. The management element in each node is able to communicate with the management element in other nodes using a self organising network (SON) protocol, as will be apparent to a skilled person. The details of such a self organising network (SON) protocol are not relevant to the principles of the present invention, and can easily be established by a skilled person, and therefore the details of the self organising network protocol will not be explained in more detail in the present description.

Embodiments of the invention will now be described with reference to the

accompanying drawings.

Figure 1 is a schematic diagram showing an exemplary arrangement in which embodiments of the invention may be implemented. Details that are not relevant to the invention have been omitted.

In Figure 1 two network nodes 2, 4 and an operation and maintenance O&M node 6 of a communication network are shown. In addition two neighbour nodes 8, 10 are shown. One neighbour node 8 is integrated with the network node 4, whereas the other neighbour node 10 is a stand-alone node.

The network nodes 2, 4 are provided with a respective management element 12, 14 that communicates with other management elements using a self organising network protocol in the exemplary embodiment, as will be described in the following

description.

The network nodes are provided with respective radio elements 16, 18 for

communicating with user devices (not shown) attached to the communication network. Each of the radio elements 16, 18 is provided with a respective transfer element 20, 22 that is arranged to handover user devices accessing communication services through the network nodes 2, 4 to another node or to carry out a cell re-selection process for a user device attached to the communication node 2, 4.

The neighbour nodes 8, 10 are provided with respective radio elements 23, 24 for communicating with user devices (not shown) attached to the respective neighbour node 8, 10.

The communication technology operating in the communication network and used by respective communication network radio elements 16, 18 has a higher average power per user device than the communication technology used by radio elements 23, 24 of neighbor nodes 8, 10. For example, the communication technology used by the radio elements 23, 24 of neighbour nodes 8, 10 to provide communication services to user devices may be a shorter range communication technology compared with the communication technology used by the radio elements 16, 18 in the communication network to provide communication services to user devices. In the exemplary embodiment, the radio elements 23, 24 of the neighbor node operate a wireless local area network (WLAN). In the exemplary embodiment the radio elements 16, 18 of the network nodes of the communication network operate a cellular communication network.

The neighbour nodes 8, 10 are provided with a respective management element 26, 28 that communicates with the other management elements using a self organising network protocol, as will be described in the following description. The neighbour nodes 8, 10 are provided with a respective congestion element 30, 32 that determines the degree of congestion being experienced by the neighbour node 8, 10 in supplying communication services to users. The congestion element 30, 32 may form part of the respective radio element 23, 24 in some embodiments, as will be apparent to a skilled person. Typically, the neighbour node 8, 10 is able to accommodate a certain number of users, and additional users seeking to use the communication service of the neighbour node beyond the limit indicates a degree of congestion of the neighbour node. The neighbour nodes 8, 10 are provided with respective parameter sets 34, 36 for operation of a management function by the respective management element 26, 28 in accordance with embodiments of the invention, as will be explained in more detail in the following description.

The operation and maintenance (O&M) node 6 of the communication network is also provided with a management element 40 that communicates with the other management elements using a self organising network protocol as will be described in the following description. In addition, the operation and maintenance (O&M) node 6 is also provided with neighbour node parameters record 42 that corresponds with the parameter sets 34, 36 for respective neighbour nodes 8, 10.

As will be understood by a skilled person, in the exemplary embodiment the

management elements 12, 14, 26, 28, 40 are able to communicate with each other using a self organising network protocol. Typically, using this protocol the management elements 12, 14, 26, 28, 40 are able to discover the identity and functionality of nearby nodes. In addition, in some arrangements it is possible for one management element to subscribe to information generated by another node, so that the information is periodically sent to the subscribing management element.

In the exemplary embodiment shown in Figure 1 , the management elements are shown coupled to other management elements required by the present invention. However, other connections may also be made in an implementation of the invention, as will be apparent to a skilled person.

In the exemplary embodiment the management element 12, 14 in each of network nodes 2, 4 respectively is coupled to and communicates with the management element of neighbour nodes. In the case of management element 12, only neighbour node 10 is close enough to be considered a neighbour node, and therefore management element 12 of network node 2 is coupled to and communicates with management element 28 of network node 10. In the case of management elementl4 of network node 4, both the node 8 and node 10 are close enough to be considered as neighbour nodes, and the management element 14 is coupled to and communicates with both management element 26 of neighbour node 8 and management element 28 of neighbour node 10. Further, the management element 40 in the operation and maintenance (O&M) node 6 of the communication network in the exemplary embodiment is coupled to and communicates with the respective management element 26, 28 of all the available neighbour nodes 8, 10.

The operation of the management elements 12, 14, 26, 28, 40 in accordance with embodiments of the invention will be explained with reference to the accompanying drawings.

Figure 2 is a flowchart showing steps of a method carried out by the nodes in a communication network in an exemplary embodiment of the invention. In the exemplary embodiment shown in Figure 1 , the method shown in the flowchart of Figure 2 is carried out by the management elements 12, 14 in network nodes 2, 4 respectively and by management element 40 in the operation and maintenance (O&M) network node 6.

In a first step 50, the communication network nodes 2, 4, 6 subscribe to traffic load notifications indicating available load capacity at a neighbour node. In the exemplary embodiment, this step is taken using a self-organising network protocol.

In a second step 52, the communication network node 52 receives from the neighbour node a load notification indicating available load capacity at the neighbour node. The load notification may indicate the available load capacity at a neighbour node by including a descriptor of the spare capacity at the neighbour node in the load notification in some embodiments.

In some embodiments of the invention, the load notification is only sent by the neighbour node 8, 10 when the neighbour node 8, 10 has spare capacity and therefore the receipt of a load notification in itself provides an indication that load capacity is available at the neighbour node 8, 10. In embodiments of the invention where the load notification is only sent by the neighbour node 8, 10 when the neighbour node has spare capacity, the receipt of a load notification may be understood by the network node as indicating that the neighbour node 8, 10 is able to accept a user device transfer from a communication network node.

Figure 3 is a flow chart showing steps of a method carried out in the neighbour nodes 8, 10. In the exemplary embodiment shown in Figure 1, the method shown in the flowchart of Figure 3 is carried out by the management elements 26, 28 in neighbour node 8, 10.

In a first step 54 a request is received for subscription of a network node 2, 4, 6 to load notifications indicating available load capacity at the neighbour node 8, 10. In the exemplary embodiment, this step is taken using a self-organising network protocol. In the exemplary embodiments the request for subscription of a network node is received from that network node. However, in some embodiments one network node may send a request for subscription of another network node to load notifications. For example, in some embodiments it may be envisaged that an operation and maintenance (O&M) node 6 may send a request for subscription of a communication node 2, 4 of the communication network to load notifications.

In a second step 56 a load notification is sent to network nodes for which a subscription request has been received. As indicated above, in some embodiments the load notification may indicate the available load capacity at a neighbour node, for example by including a descriptor of the spare capacity at the neighbour node in the load notification.

In some embodiments of the invention, the load notification is only sent by the neighbour node 8, 10 when the neighbour node 8, 10 has spare capacity. For example, in some embodiments of the invention, the load notification is only sent by the neighbour node 8, 10 when the neighbour node 8, 10 is able to accept a user device transfer from a communication network node. The network nodes are then able to take the availability of load capacity of the neighbour node 8, 10 into account in operation of the communication network nodes 2, 4, 6. The operation of the nodes of the communication network 2, 4, 6 and the operation of the neighbour nodes 8, 10 in accordance with embodiments of the invention will be described in more detail with reference to Figures 4-8. The method steps in these Figures that are the same as, or correspond with, method steps in Figures 2 and 3 have been given the same reference numerals.

Figure 4 is a flow chart showing steps of a method carried out in a neighbor node 8, 10 in embodiments of the invention. In the exemplary embodiment shown in Figure 1 , the method shown in the flowchart of Figure 4 is carried out by management element 26, 28 within the neighbor node 8, 10.

In this method at least one threshold for load information is used to determine whether or not a load notification is to be sent from the neighbor node 8, 10 to the

communication network nodes 2, 4, 6. This feature can be used in the exemplary embodiment to create a situation in which a load notification indicating available load capacity at a neighbour node is sent to the network nodes only when the neighbor node has spare capacity. In some embodiments of the invention, the load notification is only sent by the neighbour node 8, 10 when the neighbour node 8, 10 has spare capacity.

In this method, a set of subscribed network nodes is maintained at the neighbor node 8, 10. The set of subscribed network nodes are all the network nodes for which a load notification subscription has been received, and therefore are the set of network nodes to which load notifications are sent. The set of subscribed network nodes may be maintained in a database or as a simple list or in any other format as seems appropriate to a skilled person.

In a step 54, a request for a subscription of a network node 2, 4, 6 to load notifications indicating available load capacity is received at the neighbor node 8, 10, as has been described above with reference to Figure 3. The network node might be a communication node 2, 4 of the communication network or might be the operation and maintenance node 6 of the communication network.

In step 58, a set of subscribed network nodes is updated. In some embodiments, this step may include a step of adding the network node for which the request was received in step 54 to a list of network nodes that are subscribed to receive load notifications.

In step 60, which occurs periodically as will be clear from the following description, neighbor node load information is determined from the traffic loading being experienced by the neighbor node 8, 10. This step may be carried out in different ways in different embodiments of the invention as selected by a skilled person.

In step 62, it is determined whether a load notification is to be sent, as will be explained in more detail below. In embodiments of the invention, it is determined whether a load notification is to be sent by comparing the traffic load at the neighbor node 8, 10 as determined in step 60 with a threshold that is stored in the neighbor node operational parameter set 34, 36. Load notifications may be sent in step 56 to network nodes 2, 4, 6 in the subscription list when the current traffic load at the neighbor node 8, 10 is less than a load notification threshold. In the exemplary embodiment, the load notification threshold is set at a level at which load notifications are sent in step 56 to network nodes for which a subscription request has been received when the results of the step 62 of comparing indicate that the neighbour node is able to accept a user device transfer from a communication network node. In some embodiments more than one threshold setting may be used. In the exemplary embodiment a first threshold, which is the load threshold setting below which load notifications are enabled, and a second threshold, which is the threshold above which load notifications are disabled, are provided. The use of two threshold settings in this manner may provide a hysteresis effect and may have the effect of promoting stability. Clearly, where two or more load notification thresholds are provided, the current traffic load may be compared with one or more than one of the load notification thresholds as selected by a skilled person As will be explained in the following description, the thresholds can be adjusted during operation in order to ensure the desired operation of the communication system as a whole. The updating of the thresholds can be achieved by the re-configuration of a threshold parameter in the neighbor node parameter set 34, 36. The determination of a new threshold value may be carried out by the operation and maintenance (O&M) node 6 of the communication network in a manual mode of operation, and may be carried out by the neighbor node 8, 10 in an automatic mode of operation.

If it is determined that a load notification is not required, step 62-n, the operation passes to step 64. In step 64 the neighbor node 8, 10 waits for a time period before returning to step 60 to determine a new traffic load. In the exemplary embodiment the time period is defined by a periodicity parameter in the neighbor node parameter set 34, 36.

If it is determined that a load notification is required, step 62-y, in step 56 a load notification is sent to network nodes in the set of subscribed network nodes.

Thereafter once again the operation passes to step 64 in which step the neighbor node 8, 10 waits for a time defined by a periodicity parameter stored in the neighbor node parameter set 34, 36 before returning to step 60 to determine a new traffic load.

Figure 5 is a flow chart showing steps of a method carried out in the communication nodes 2, 4 of the communication network. In the exemplary embodiment shown in Figure 1, the method shown in the flowchart of Figure 5 is carried out by the

management elements 12, 14 in network nodes 2, 4 respectively.

The first and second steps 50, 52 of the method shown in Figure 5 have been discussed with reference to Figure 2. Thus, as discussed above, in a first step 50 the

communication network nodes 2, 4 subscribes to traffic load notifications for a neighbour node 8, 10. In a second step 52, the communication network node 2, 4 receives a load notification indicating the available load capacity at the neighbour node 8, 10. This traffic load notification is the traffic load notification sent by the neighbour node in step 56 of Figures 3 or 4, for example. In a third step 70, the network node 2, 4 determines whether or not to transfer traffic load at the network node 2, 4 to the neighbor node 8, 10. The network node 2, 4 of the communication network is able to determine whether to transfer traffic load to the neighbor node 8, 10 by considering the availability of load capacity of the neighbor node 8, 10 instead of, or in addition to, the traffic loading that the network node 2, 4 is experiencing.

In accordance with embodiments of the invention the determination whether to transfer traffic load is taken with the aim of reducing power consumption across both the communication network and the neighbor node. As a result the utilization of the communication resources may be improved and the traffic load balanced across the different communication technologies available.

In addition, in some embodiments, in the event that it is determined in step 70 that load can be transferred from the communication network to the neighbor node 8, 10, the network node 2, 4 may determine which user device should transfer to the neighbor node, or undergo cell re-selection based upon factors such as the security requirements or quality of service requirements associated with the user device or traffic load, for example.

If the result of step 70 is a positive determination, the network node 2, 4 may instruct the user device to transfer part of or all of the user device traffic load to the neighbour node. In some embodiments, the network node 2, 4 may also communicate with the neighbor node 8, 10 with regard to the transfer of the traffic load of the user device to the neighbor node 8, 10.

Thus in the exemplary embodiment in which the neighbor node 8, 10 operates a wireless local area network (WLAN), for example a wireless local area network (WLAN) based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, and the communication network is a longer range communication network such as a LTE network, the LTE base station is able to transfer some of its traffic load to the neighbour node operating a wireless local area network (WLAN) based on the availability of spare capacity in the neighbor node. Since the neighbor node 8, 10 has a lower power per user that the communication network, the total power used to supply communication services to all the relevant user devices may be reduced or minimized. In addition, load capacity in the communication network is increased.

As will be appreciated by a skilled person, in the situation where the traffic load at the neighbor 8, 10 node increases, the neighbor node 8, 10 will no longer have spare capacity. The neighbor node 8, 10 will stop sending traffic load notifications informing the subscribed network nodes 2, 4, 6 of the spare capacity at the neighbor node 8, 10.

In some embodiments, at least one threshold used by the neighbor node 8, 10 in determining whether to send traffic load notifications to the traffic nodes 2, 4 of the communication network may be dynamically determined. In some embodiments at least one threshold may be dynamically determined using the current and/or historical traffic loading data and/or the current and/or historical congestion experienced by the neighbor node 8, 10.

In some embodiments, the operation and maintenance (O&M) node 6 of the

communication network determines new thresholds periodically and communicates with the neighbor node 8, 10 to update the threshold used by the neighbor node 8, 10. In other embodiments, the neighbor node 8, 10 updates at least one threshold itself.

The operation of the operation and maintenance node (O&M) node 6 and the neighbor node 8, 10 in these different modes is explained with reference to Figures 6-8.

Figure 6 is a flow chart showing steps of a method carried out by an operation and maintenance (O&M) node 6 of the communication network when the operation and maintenance (O&M) node 6 is in an Enabled Manual mode parameter setting, step 80. In the exemplary embodiment shown in Figure 1 , the method shown in the flowchart of Figure 6 is carried out by the management element 40 in the operation and maintenance (O&M) node 6.

In the Enabled: manual mode parameter setting, the operation & maintenance (O&M) node 6 is responsible for dynamically setting at least one threshold used by the neighbor node 6 in determining whether to end traffic load notifications indicating available load capacity to the traffic nodes 2, 4 of the communication network. Method steps that are the same as or are similar to method steps as described above have been given the same reference numerals.

In step 82, the operation and maintenance node (O&M) node 6 subscribes to congestion notification for the neighbor node 8, 10. Typically, this would be achieved using the self-organizing network protocol as described above, or using any suitable protocol as selected by a skilled person.

In step 50 the operation & maintenance (O&M) node 6 subscribes to load notifications indicating available load capacity at the neighbor node 8, 10. In the exemplary embodiment this is achieved using the self organizing network protocol, as described above with reference to Figure 2.

In step 84, congestion information for the neighbor node is received by the operation & maintenance node (O&M) node 6. Typically one or more pieces of received congestion information are stored at the operation and maintenance (O&M) node 6 as will be apparent to a skilled person.

In step 52 a load notification indicating available traffic capacity at neighbor node 8, 10 received by the operation & maintenance (O&M) node 6, as described above with reference to Figure 2.

In step 86 the operation and maintenance (O&M) node 6 determines at least one traffic load threshold for the neighbor node 8, 10. The threshold may be determined using any suitable method as selected by a skilled person. In embodiments of the invention, the threshold is determined using information from information relating to the available capacity in the load notification received in step 52. In some embodiments the threshold is determined using neighbor node congestion information received in step 84. In step 88, the operation and maintenance (O&M) node 6 configures at least one traffic load threshold for the neighbor node 8, 10. In the exemplary embodiment as described below, the configuration of the threshold is achieved by the operation & maintenance (O&M) node 6 updating a threshold parameter in the neighbor node 8, 10, for example by sending an threshold parameter updating message from the operation and maintenance (O&M) node 6 to the neighbor node 10. In addition, in some embodiments a load threshold parameter for the neighbor node 8, 10 stored at the operations and maintenance (O&M) node 6 is also updated. Thereafter, the operation returns to step 84.

In different implementations as selected by a skilled person, a time delay may be introduced between the different determinations of the threshold. In some embodiment a threshold may be determined in step 86 using information from load notifications and congestion notifications received over a period of time.

As described above, in some arrangements the threshold parameter may be updated by the neighbor node 8, 10, instead of being updated by the operation and maintenance (O&M) node 6 directly. However, in such circumstances, the operation and

maintenance (O&M) node 6 may retain a supervisory role. In the exemplary

embodiment shown in Figure 7, this is achieved by the monitoring of the congestion at the neighbor node 8, 10 by the operation and maintenance (O&M) node 6.

Figure 7 is a flow chart showing the steps in the method carried out by the operation and maintenance (O&M) node of a communication network in accordance with embodiments of the invention. In the exemplary embodiment shown in Figure 1, the method shown in the flowchart of Figure 7 is carried out by the management element 40 in the operation and maintenance (O&M) node 6.

In Figure 7, the operation and maintenance (O&M) node 6 starts in the enabled manual mode, as described above with reference to Figure 6, and therefore steps 80, 82, 50, 84, 52, 86 and 88 are as described above with reference to Figure 6.

In the embodiment shown in Figure 7, after the traffic load threshold for the neighbor node 8, 10 has been configured in step 82 the method moves to step 92 in which it is determined whether the neighbor node 8, 10 is congested.

One way in which this may be achieved in accordance with an exemplary embodiment is to determine whether congestion notifications are being received by the operation and maintenance (O&M) node 6. In embodiments of the invention, the congestion notifications may for example be stored over a fixed period to determine whether congestion notifications are being received.

If the neighbor node 8, 10 is congested, step 92 - y, the operation and maintenance (O&M) node 6 retains control over the setting of the thresholds, and so control returns to step 84 and operation remains in the manual control mode.

If the neighbor node 8, 10 is not congested, step 92-n, the thresholds set are considered to be well adapted, and the operation passes to an automatic control mode, step 94, in which control over threshold setting is passed to the neighbor node 8, 10 itself. In the exemplary embodiment as described below, the configuration of the neighbor node in automatic mode is achieved by the operation & maintenance (O&M) node 6 updating a mode parameter in the neighbor node 8, 10, for example by sending a mode parameter updating message from the operation and maintenance (O&M) node 6 to the neighbor node 10. In addition, in some embodiments a mode parameter for the neighbor node 8, 10 stored at the operations and maintenance (O&M) node 6 is also updated.

In this mode it is not necessary for the operation and maintenance (O&M) node 6 to monitor the load notifications from the neighbor node 8, 10, so in some embodiments in step 96 the operation and maintenance node 6 unsubscribes from the load notifications from the neighbor node 8, 10. However, in some embodiments the unsubscribing of the operation and maintenance node 6 from the load notifications of the neighbor node 8, 10 is performed automatically by the neighbor node 8, 10 in response to the change in the mode from manual mode to automatic mode.

In step 98 the congestion experienced by the neighbor node 8, 10 is monitored by determining whether the neighbor node 8, 10 is congested. Again, one way in which this may be achieved in accordance with an exemplary embodiment is to determine whether congestion notifications are being received by the operation and maintenance (O&M) node 6. In embodiments of the invention, the congestion notifications may for example be stored over a fixed period to determine whether congestion notifications are being received. While no, or possibly only minimal in some embodiments, congestion is detected, step 98-no, the automatic mode can be left in place and the operation and maintenance node 6 merely continues monitoring the congestion of the neighboring node 8, 10 in step 98. If, however, it is determined that there is congestion at the neighbor node 8, 10, step 98- y, the operation & maintenance (O&M) node 6 reverts to a manual mode and configures the neighbor node 8, 10 in manual node again, step 100. In the exemplary embodiment as described below, the configuration of the neighbor node in manual mode in step 100 is achieved by the operation & maintenance (O&M) node 6 updating a mode parameter in the neighbor node 8, 10, for example by sending a mode parameter updating message from the operation and maintenance (O&M) node 6 to the neighbor node 10. In addition, in some embodiments a mode parameter for the neighbor node 8, 10 stored at the operations and maintenance (O&M) node 6 is also updated. Thereafter, the operation and maintenance node returns to step 50 to subscribe once again to the load notifications for the neighbor node 8, 10.

Figure 8 is a flow chart showing the operation in a neighbor node 8, 10 during manual mode operation and during automatic mode operation to configure the thresholds used by the neighbor node 8, 10 to determine whether to send load notifications to communication network nodes. In the exemplary embodiment the method described with reference to Figure 8 is carried out by a management element 26, 28 within the neighbor node 8, 10. As described above with reference to Figure 3 and 4, it will be understood by a skilled person that the neighbor node 8, 10 continues to send load notifications to the set of subscribed nodes of the communication network independently of the methods employed to update the load notification threshold. The left hand side of Figure 8 shows steps taken by the neighbor node 8, 10 in a manual mode of operation, in which the operation and maintenance (O&M) node 6 determines load notification thresholds. The right hand side of Figure 8 shows steps taken by the neighbor node 8, 10 in an automatic mode of operation, in which the neighbor node 8, 10 determines load notification thresholds. In embodiments in which automatic mode operation is not available, the neighbor node 8, 10 follows only those steps appropriate to the manual mode of operation.

The manual mode of operation, in which the operation and maintenance (O&M) node 6 determines load notification thresholds, will be described first. The operation of the neighbor node 8, 10 in the manual mode corresponds with the operation of the operation and maintenance (O&M) node 6 as described above with reference to Figure 6. In the manual operation mode, in a first step 106 a congestion notification subscription request for the operation and maintenance (O&M) node 6 is received. This is the congestion notification request that was sent by the operation and maintenance (O&M) node 6 in step 82. In some embodiments, a congestion management function of the neighbor node 8, 10, and not the management element 26, 28 in the neighbor node 8, 10, may handle the subscription to congestion information by the operation and maintenance (O&M) node 6.

In step 54 a load notification subscription request for the operation and maintenance (O&M) node 6 is received by the management element 26, 28 in the neighbor node 8, 10 using the self organizing network protocol. This is the load notification request that was sent by the operation and maintenance (O&M) node 6 in step 50.

In step 108, the congestion information at the neighbor node 8, 10 is sent to the operation and maintenance (O&M) node 6. Again it is noted that in some embodiments a congestion management element 30, 32 of the neighbor node 8, 10, and not the management element 26, 28 in the neighbor node 8, 10, handles the sending of congestion information to the operation and maintenance (O&M) node in step 108.

In step 56 the management element 26, 28 in the neighbor node 8, 10 sends a load notification indicating its available load capacity to the operation and maintenance (O&M) node 6, as one of the set of subscribed communication network nodes, as will be apparent to a skilled person from a careful consideration of the accompanying description. In the manual mode of operation, as described above with regard to Figure 7, the operation and maintenance (O&M) node 6 determines at least one new load threshold for the neighbor node 8, 10 in step 86 and configures the or each load threshold for the neighbor node 8, 10 in step 88. Thus in step 110 of Figure 8 the neighbor node 8, 10 receives a load threshold configuration from the operation and maintenance (O&M) node 6, and configures the threshold parameter to correspond with the received updated load threshold value. In the exemplary embodiment, the re-configuration of the threshold is achieved by updating the threshold parameter in the stored parameter set 34, 36, as will be explained in more detail with reference to Figures 9-11.

Next, in step 112 the neighbor node 8, 10 checks whether the automatic mode has been configured by the operation and maintenance (O&M) node 6. In the exemplary embodiment as described below, the configuration of the neighbor node in automatic mode is achieved by the operation & maintenance (O&M) node 6 updating a mode parameter in the neighbor node 8, 10, for example by sending a mode parameter updating message from the operation and maintenance (O&M) node 6 to the neighbor node 10.

If not, step 112-n, the neighbor node 8, 10 operation returns to step 108 and the neighbor node 8, 10 continues to send congestion and traffic load information to the operation and maintenance (O&M) node 6 and to receive a fresh load threshold configuration from the operation and maintenance (O&M) node 6.

If the automatic mode is configured in step 112-y, the automatic mode parameter is enabled in step 114 in the neighbor node operation parameter set, and the neighbor node 8, 10 moves into the automatic mode operation in which the neighbor node 8, 10 sets at least one load notification threshold.

In a first step 120 of the automatic mode operation, a threshold determination function of the management element 26, 28 internally subscribes to the congestion notifications from the congestion management element 30, 32 of the neighbor node 8, 10.

In a second step 122, a threshold determination function of the management element In some embodiments, in step 124 the operation and maintenance (O&M) node 6 is removed from the set of subscribed network nodes automatically by the management element of the neighbor node 8, 10. In other embodiments the operation and management (O&M) node 6 un-subscribes from the load notifications, as described above with reference to step 96 of Figure 7. In other embodiments the operation and maintenance (O&M) node 6 may continue to be subscribed for load notifications throughout the period of automatic mode. In step 126 congestion notifications are received in response to the subscription to congestion notifications in step 120. In step 128, load notifications are received in response to the subscription to load notifications in step 122. Both these steps 126 and 128 are shown as single steps but in different embodiments steps 126 and 128 may cover the reception of a plurality of notifications, or possibly no notifications at all in some situations.

In step 130 management element 26, 28 of the neighbor node 8, 10 determines at least one load threshold for determining the traffic load at which to send a notification to a subscribed network node. As will be apparent to a skilled person, the management element 26, 28 of the neighbor node 8, 10 may use the same method in step 130 to determine the network load threshold as the operation and maintenance (O&M) node used in step 86 in Figure 7.

In step 132 the management element 26, 28 of the neighbor node 8, 10 re-configures the load threshold parameter. In the exemplary embodiment, the re-configuration of the threshold is achieved by updating the threshold parameter in the stored parameter set 34, 36, as will be explained in more detail with reference to Figures 9-11.

In step 134 the management element 26, 28 of the neighbor node 8, 10 determines whether the manual mode configuration is required, typically by determining whether a message to that effect has been received from the management element 40 of the operation and maintenance (O&M) node 6. If the manual mode is not configured step 1354-n, the management element 26, 28 of the neighbor node 8, 10 returns to repeat steps 126-132. Thus in the automatic mode at least one load threshold for determining when load notifications are sent is determined locally in the neighbor node 8, 10.

If configuration of the manual mode is determined, step 134-y, in step 136 the mode parameter is set to enable manual mode.

Thereafter, in the exemplary embodiment the management element 26, 28 in the neighbor node 8, 10 internally unsubscribes from the traffic load notifications in step 138 and unsubscribes from the congestion notifications in step 140. These steps are the opposite of steps 120 and 122 described above.

Thereafter, the operation returns to the manual mode operation in step 106.

Figures 9-11 are schematic block diagrams of elements of exemplary nodes that are relevant to the invention.

Figure 9 is a schematic block diagram showing elements of the neighbour node 10 and the network node 2 from the arrangement shown in Figure 1.

Figure 10 is a schematic block diagram showing elements of the neighbour node 10 and the elements of the operation and maintenance (O&M) node 6 shown in Figure 1 that are used during manual mode operation.

Figure 11 is a schematic block diagram showing elements of the neighbour node 10 and the elements of the operation and maintenance (O&M) node 6 as shown in Figure 1 that are used during automatic mode operation. Elements in these drawings that are the same as, or that are similar to, elements in Figure 1 have been given the same reference numerals.

In Figure 9, the neighbor node 10 is provided with a management element 28, as described above with reference to Figure 1 , which performs the steps of the invention as described above with reference to Figures 3, 4 and 8. The management element 28 is coupled with management elements in other nodes and communicates with them using a self organizing network protocol. Typically the management element 28 will be implemented as a part of a larger self organizing network function implemented in nodes of the communication network and in the neighbour nodes. The management elements may be implemented in machine readable instructions as a computer program or as part of a computer program controlling aspects of the neighbor node behavior or in other ways as selected by a skilled person. Neighbour nodes 10 is provided with a radio element 24 for communicating with user devices (not shown) attached to the neighbour node 10, as described above with reference to Figure 1. Neighbor node 10 is also provided with a congestion

management element 32. The congestion management element 32 may form part of the respective radio element 23, 24 in some embodiments, as will be apparent to a skilled person.

The congestion management element 32 maintains congestion information 150 and throttling load thresholds 152, and the congestion management element 32 operates in accordance with known principles for such networks as will be understood by a skilled person from a consideration of the description of the present invention. Again, a skilled person might implement the congestion management function in different ways to meet operational requirements. Typically the congestion management function is

implemented in machine readable instructions as a computer program or as part of a computer program controlling aspects of the neighbor node behavior.

The neighbor node 10 is also provided with a parameter set 36 containing at least one parameter relevant to the operation of the invention. The parameter set 36 may be implemented in any suitable store in the neighbor node 10 that is accessible by the management element 28. The management element 28 is able to access the parameter set 36 to update parameters stored therein, and is also able to access the parameters during the operation of the embodiments of the invention.

The parameters in the parameter set 36 are generally parameters set by the operation and maintenance (O&M) node 6 of the communication network for use by the neighbor node 10 during the operation of the invention. As will be understood from a

consideration of the above description of the automatic mode, in some situations a load threshold parameter may be set by the neighbor node management element 28. In other situations parameters in the parameter set 36 may be updated by the management element 28 after receipt of an instruction or message for example from the management element 40 of the operation and maintenance (O&M) node 6.

A mode parameter 154 is provided to indicate whether the neighbor node 10 is operating in a manual mode or in an automatic mode as has been described above with reference to Figures 7 and 8. This parameter may be updated by the management element 28 in response to a mode configuration message received from the operation and maintenance (O&M) node 6.

A first load threshold parameter 156 and a second load threshold parameter 158 are shown in the exemplary embodiment in Figures 9-11. The provision of two load threshold parameters 156, 158 enables a hysteresis element to be introduced in the traffic load notifications. However, as will be apparent to a skilled person,

embodiments of the invention may be envisaged in which only a single load threshold is used.

Load threshold parameters 156, 158 may be updated by the management element 28 in response to a load threshold configuration message received from the operation and maintenance (O&M) node 6 in the manual mode, or may be updated by the

management element 28 of the neighbor node.

The first load threshold parameter 156 in the exemplary embodiment relates to the load threshold setting below which notifications to the set of subscribed network nodes are enabled. The second load threshold parameter 158 in the exemplary embodiment relates to the load threshold setting above which notifications to the set of subscribed network nodes are disabled. A periodicity parameter 160 is provided in the exemplary embodiment shown in Figures 9-11. The periodicity parameter is used in step 64 in Figure 4 as described above to define the interval between each determination of traffic load and therefore between each potential load notification.

The neighbor node 10 is also provided with a load information element 164 coupled to the management element 28. The load information element 164 operates to determine the current load experienced by the neighbor node 10, for example as described above in connection with step 60 shown in Figure 5. The load information element 164 may use one of a number of different methods to determine the current load experienced by the neighbor node, as will be apparent to a skilled person.

The neighbor node 10 is also provided with a subscription list 166 for recording the set of network nodes for which a load notification subscription has been received. In different embodiments the subscription list may be recorded in a database or a simple list or in other manners as selected by a skilled person. The management element 28 is coupled to the subscription list 166 to update the list following receipt of a successful subscription or un- subscription request, as discussed above with reference to step 58 in Figure 4 and step 96 in Figure 7. In addition, the management element 28 accesses the subscription list 166 in order to determine the nodes to which a load notification should be sent, for example as discussed with regard to step 56 in Figure 4.

The exemplary network node 2 in Figure 9 is shown having a load notification store 170 as well as the management element 12 and the transfer element 20 as described above.

In some embodiments, the transfer element 20 is directly coupled to the management element 12 to receive available load capacity information directly from the

management element 12. For example, in embodiments in which the receipt of the load notifications indicates that load capacity is available at the neighbor node, the management element 12 may merely notify the transfer element 20 of load capacity at the neighbor node. In response to this notification the transfer element 12 may then determine a transfer of one or more user devices attached to the network node 2 of the communication network to the neighbor node 10. In some embodiments, the management element 12 is coupled to the load notification store 170 to store load notification data from the load notifications in the load notification store 170. In some embodiments, the management element 12 stores load data relating to the available load capacity at the neighbor node 10 extracted from the load notification that the management element 12 receives from the management element 28 of neighbor node 10, as described above with reference to Figure 2 and 5. In some embodiments the load notification store 170 merely stores a record of receipt of the load notifications as the load notification data.

The transfer element 20 may be coupled indirectly to the management element 12 via the load notification store 170. The transfer element 20 is arranged to access the load notification data stored in the load notification store 170, and is operable to use the data in determining a transfer of one or more user devices attached to the network node 2 of the communication network to the neighbour node 10 in response to the load notification indicating available load capacity at the neighbour node 10.

In Figure 10, the elements in the neighbor node 10 are the same as has been described above for Figure 9, and therefore these elements will not be described further.

The operation and maintenance (O&M) node 6 is provided with a management element 40 coupled to a parameter record 42, as shown in Figure 1.

The operation and maintenance (O&M) node 6 is also provided with a load notification store 174 to which the management element 40 is also coupled to store load notification data from the load notifications received by the management element 40, as described above in connection with step 52 in Figure 2, 6 and 7. In some cases, the load notification data may merely relate to the fact that a load notification indicating available capacity at the neighbor node has been received by the management element 40 of the operation and maintenance node. In other embodiments data relating for example the load capacity available at the neighbor node may be stored in the load notification store 174. The operation and maintenance (O&M) node 6 is also provided with a congestion notification store 176 to which the management element 40 is also coupled to store congestion data received by the management element 40, as described above in connection with step 84 in Figures 6 and 7.

The parameter record 42 for the operation and maintenance node 6 stores a set of parameters for the neighbor node 10. In general it is to be expected that the operation and maintenance node will have a parameter record 42 for each of the neighbor nodes known to the operation and maintenance node 6.

The set of parameters stored in parameter record 42 corresponds with the set of parameters stored at the neighbor node 10.

A mode parameter 178 is provided corresponding with the mode parameter 154 stored in the neighbor node 10. The mode parameter 178 is provided to indicate whether the neighbor node 10 is operating in a manual mode or in an automatic mode as has been described above with reference to Figures 7 and 8. Mode parameter 178 may be updated by the management element 40 in response to a determined change in the mode configuration described above in connection with steps 94 and 100 in Figure 10.

A first load threshold parameter 180 for the neighbor node 10 and a second load threshold parameter 182 for the neighbor node 10 are provided respectively

corresponding to the first load threshold parameter 156 and a second load threshold parameter 158 stored in the neighbor node 10. Again, embodiments of the invention may be envisaged in which only a single load threshold is used. Load threshold parameters 180, 182 may be updated by the management element 40 in response to the determination of a traffic load threshold and configuration of the traffic load threshold in steps 86 and 88 of Figures 6 and 7. In the exemplary embodiment, the first load threshold parameter 180 relates to the load threshold setting below which notifications to the set of subscribed network nodes are enabled. The second load threshold parameter 182 relates to the load threshold setting above which notifications to the set of subscribed network nodes are disabled. A periodicity parameter 184 is also provided, which corresponds with the periodicity parameter 160 stored in the neighbor node 10. The periodicity parameter 160 in the neighbor node 10 is used by the neighbor node in step 64 in Figure 4 as described above to define the interval between each determination of traffic load and therefore each potential load notification.

In Figure 11 , the neighbour node elements are the same as have been described above for Figure 9, and therefore these elements have not been described further in connection with Figure 11.

In Figure 11 the operation and maintenance (O&M) node is also provided with a congestion threshold 186 that is coupled to the management element 40. In addition, as described above, the management element 40 also has access to the congestion information received from the neighbor node 10 and stored in the congestion information store 176 as described above.

In the automatic mode of operation, the exemplary operation and maintenance node 6 compares the congestion information store 176 with the congestion threshold 186 to determine whether the neighbor node is congested and whether a return to the manual mode in which the load threshold is set by the operation and maintenance (O&M) 6 is required.

Thus, in accordance with an exemplary embodiment of the invention:

1. Neighbor nodes (for example Wi-Fi access points (AP)/access control (AC)) maintain load data locally.

Neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) maintain existing congestion data of number of clients not allowed to connect over time (i.e. number of connection rejects over time).

Sharing of load information between neighbor nodes (for example Wi-Fi access point (AP)/ access control (AC)) and communication nodes (macrocell/picocell nodes) will be subscription based, initiated by the communication nodes (macrocell/picocell nodes) and controlled by the neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)).

Sharing of load information between neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) and an operation and maintenance (O&M) node 6 will be subscription based, initiated by the operation and maintenance (O&M) node 6 and controlled by the neighbor nodes (for example Wi-Fi access point (AP)/access control (AC).

Sharing of existing congestion information between neighbor nodes (for example Wi-Fi access point (AP)/access control (AC) and an operation and maintenance (O&M) node 6 will be subscription based, initiated by the operation and maintenance (O&M) node 6 and controlled by the neighbor nodes 6 (for example Wi-Fi access point (AP)/access control (AC)).

Sharing of existing congestion internally in neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) will be subscription based, initiated by self organizing network (SON) features and controlled by the existing

Congestion Control function.

Neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) support following re-configurable parameters:

a. Enable [Manual, Automatic]/Disable subscription of load function. This can be a time controlled subscription (e.g. off-peak, peak or specific time period).

b. Load threshold setting below which notifications are enabled

c. Load threshold setting above which notifications are disabled d. Periodicity of sending notifications

Neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) may be preconfigured with appropriate settings so as to support a 'plug & play' rollout solution.

Neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) will implement self organizing network (SON) algorithm which based on configured parameters specified above will make available load information to

communication nodes (macro cell/pico cell nodes) and an operation and maintenance (O&M) node which have successfully subscribed for the load information.

Neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) will make available existing congestion information to an operation and maintenance (O&M) node 6 which have successfully subscribed for congestion information.

10. Communication nodes (for example macrocell or picocell nodes) will

notifications as input to the transfer and handover functions.

11. An operation and maintenance (O&M) node 6 will use the notifications as an input to reconfiguring the load threshold settings in an associated neighbor node 8, 10, for example Wi-Fi access point (AP)/access control (AC). If the self organizing network (SON) feature mode parameter is set to Enable: Automatic, this implies that reconfiguration of threshold settings in the associated Wi-Fi access point is performed locally. The operation and maintenance (O&M) node 6 must first set the mode parameter to Enable: Manual before subscribing for notifications.

In summary, in the exemplary embodiment of the invention the management feature will be deployed by default in;

1. An operation and maintenance (O&M) node of the communication network. 2. Communication nodes (macrocell/picocell nodes) of the communication network.

3. Neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) whether integrated with a communication node or whether a stand-alone node.

Once automated, the power management feature will be deployed by default in;

4. Communication nodes (macrocell/picocell nodes) of the communication network. 5. Neighbor nodes (for example Wi-Fi access point (AP)/access control (AC)) whether integrated with a communication node or whether a stand-alone node.

Thus it can be seen that embodiments of the invention described herein provide methods and apparatus enabling the transfer of traffic load in a communication network, such as a LTE network, to a lower power per user node, such as a wireless local area (WLAN) or Wi-Fi node, based on the availability of capacity at the node having a lower power per user. Handover or cell re-selection algorithms are able preemptively to trigger a handover or a cell re-selection based on the availability of capacity at the lower power node so as to reduce overall power consumption for the operators' network.

Implementation of embodiments of the invention may reduce overall power

consumption in communication networks for a given number of users. In addition, implementation of embodiments of the invention may result in smoothing of the network load across available access technologies. It is expected that implementation of embodiments of the invention will reduce the operational expenditure (OPEX) of the network operator and support a growth in network capacity in a cost efficient manner.

Claims

CLAI MS

A method in a node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology, comprising the steps of:

subscribing to load notifications indicating available load capacity at a neighbour node that is adapted to provide, in use, communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology, and

receiving load notifications from the neighbour node.

The method as claimed in claim 1 in which the receipt of a load notification indicates that the neighbour node is able to accept a user device transfer from a communication network node.

The method as claimed in one of claims 1 or 2 further comprising the step of determining a transfer of one or more user devices attached to the network node of the communication network to the neighbour node in response to the load notification.

The method of claim 3 in which the determination to transfer user devices to the neighbour node is made in response to the receipt of one or more load notifications.

The method as claimed in claim 3 or 4 in which in the step of determining transfer of a user device, the receipt of a load notification indicating a high load capacity at the neighbour node increases the likelihood that transfer of one or more user devices from the network node to the neighbour node is determined. 6. The method as claimed in one of claims 3-5 further including the step of

instructing a user device to transfer to the neighbour node.

7. The method as claimed in one of claims 1 or 2 in an operation and maintenance node of the communication network, the method further comprising the steps of:

determining at least one load notification threshold for the neighbour node using received load notifications; and

configuring the at least one load threshold at the neighbour node.

The method as claimed in claim 7 in an operation and maintenance node further comprising the step of:

subscribing to a congestion notification indicating congestion at the neighbour node; and

receiving congestion notifications from the neighbour node at the operation and maintenance node of the communication network.

The method as claimed in one of claims 7or 8 in which in a manual operation mode of the operation and maintenance node, the step of determining at least one load notification threshold uses information from at least one congestion notification.

10. The method as claimed in one of claims 7-9 further comprising the steps in a manual operation mode of:

determining whether the neighbour node is congested by monitoring neighbour node congestion notifications received at the operation and maintenance, O&M, node; and

configuring the neighbour node in an automatic operation mode in which the neighbour node determines at least one load notification threshold when the neighbour node is not congested.

11. The method as claimed in one of claims 7-10, further comprising the steps, in automatic operation mode, of:

determining whether the neighbour node is congested by monitoring neighbour node congestion notifications received at the operation and maintenance, O&M, node; and configuring the neighbour node in manual operation mode in response to the receipt of congestion notifications from the neighbour node.

12. A method in a neighbour node adapted to provide, in use, a communication service to a user device using a first communication technology, the method comprising the step of:

receiving a request for subscription of a network node to load notifications indicating available load capacity at the neighbour node, the network node belonging to a communication network using a second communication technology to provide a communication service to a user device that has a higher average power per user device than the first communication technology; and

sending load notifications to network nodes for which a subscription request has been received.

13. The method as claimed in claim 12 further comprising the steps of:

comparing a current load with at least one load notification threshold to determine whether load notifications are to be sent; and

sending load notification to network nodes for which a subscription request has been received when the current load is less than the load notification threshold.

14. The method as claimed in claim 13 in which the load notification threshold is set at a level at which load notifications are sent to network nodes for which a subscription request has been received when the results of the step of comparing indicate that the neighbour node is able to accept a user device transfer from a communication network node.

15. The method as clamed in one of claims 12-14 in which a set of subscribed

network nodes is maintained, further comprising the steps of

updating the set of subscribed network nodes to include a network node in response to the step of receiving a subscription request for load notification to that network node; and

sending a load notification to subscribed network nodes.

16. The method as claimed in one of claims 12-15 further comprising the step of obtaining a current traffic load. 17. The method as claimed in one of claims 12-16 further comprising the step of waiting for an interval defined by a periodicity parameter before repeating the step of comparing current traffic load with a load notification threshold.

18. The method as claimed in one of claims 12-17 further comprising in a manual mode the step of receiving at least one load threshold from a network node of the communication network; and the step of configuring at least one load threshold parameter.

19. The method as claimed in one of claims 12-18, further comprising the steps in an automatic mode of:

subscribing to internal congestion notifications

subscribing to internal load notifications;

determining at least one load notification threshold using traffic load notifications and congestion notifications; and

configuring at least one load threshold parameter.

20. The method as claimed in one of claims 12-19 further comprising the steps of:

determining whether a mode configuration update has been received from the network node of the communication network; and

in response to a positive determination, reconfiguring a neighbour node mode parameter in accordance with the received mode configuration update.

21. The method as claimed in any preceding claim wherein the communication technology used by the neighbour node to provide communication services to user devices is a shorter range communication technology compared with the communication technology used in the communication network to provide communication services to user devices.

22. The method as claimed in any preceding claim wherein the neighbour node operates a wireless local area network, WLAN.

23. The method as claimed in any preceding claim where the communication

network is a cellular communication network.

24. A machine-readable medium comprising instructions which cause a processor to perform a method in a node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology, comprising the steps of:

subscribing to load notifications indicating available load capacity at a neighbour node that is adapted to provide, in use, communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology,

receiving load notifications from the neighbour node; and

determining a transfer of one or more user devices attached to the network node of the communication network to the neighbour node in response to the load notification. 25. A machine-readable medium comprising instructions which cause a processor to perform a method in a node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology, comprising the steps of:

subscribing to load notifications indicating available load capacity at a neighbour node that is adapted to provide, in use, communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology;

receiving load notifications from the neighbour node;

configuring the at least one load threshold at the neighbour node.

26. A machine-readable medium comprising instructions which cause a processor to perform a method in a neighbour node adapted to provide, in use, a communication service to a user device using a first communication technology, the method comprising the step of:

receiving a request for subscription of a network node to load notifications indicating available load capacity at the neighbour node, the network node belonging to a communication network using a second

communication technology to provide a communication service to a user device that has a higher average power per user device than the first communication technology; and

27. Apparatus for a network node of a communication network, the communication network being adapted to provide, in use, communication services to a user device using a first communication technology, comprising:

a first management element, adapted to communicate with a second management element in a neighbour node providing communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology, the first management element being adapted to subscribe to load notifications indicating available load capacity at the neighbour node and to receive load notifications from the second management element, and

a transfer element, coupled to the first management element to receive load notification data from the load notifications, and adapted to determine a transfer of one or more user devices attached to the network node to the neighbour node in response to the load notification data.

28. Apparatus for an operations and maintenance node of a communication

network, the communication network being adapted to provide, in use, communication services to a user device using a first communication

technology, comprising:

a third management element, adapted to communicate with a second management element in a neighbour node providing communication services to a user device using a second communication technology having a lower average power per user device than the first communication technology; the third management element being adapted to subscribe to load notifications from the second management element indicating available load capacity at the neighbour node and to receive load notifications from the second management element; to determine at least one load notification threshold for the neighbour node using the received load notifications; and to configure the at least one load threshold at the neighbour node.

29. Apparatus as claimed in claim 28 further comprising a load notification store, coupled to the third management element for storing load notification data from the load notifications for use by the third management element in determining at least one notification threshold for the neighbor node.

30. Apparatus as claimed in claim 28 or 29 further comprising a congestion

notification store coupled to the third management element for storing neighbor node congestion data, for use by the third management element in determining at least one notification threshold for the neighbor node.

31. Apparatus as claimed in one of claims 28-30 comprising a parameter record containing a load threshold parameter record for the neighbor node, wherein the second management element is coupled to the parameter record to update the load threshold parameter record for the neighbor node.

32. Apparatus as claimed in one of claims 28-31 comprising a parameter record containing a mode parameter defining a mode of operation of the neighbor node.

33. Apparatus for a neighbour node adapted to provide, in use, a communication service to a user device using a second communication technology, comprising a subscription list for storing a set of subscribed network nodes for which a subscription request has been received;

a load information element operable to determine a current load experienced by the neighbor node;

a parameter set containing a load threshold parameter; and a second management element, adapted to communicate with a first management element in a network node belonging to a communication network using a first communication technology to provide a communication service to a user device that has a higher average power per user device than the second communication technology,

wherein the second management element is coupled to the subscription list to update the set of subscribed network nodes in response to a request for subscription of a network node to load notifications indicating available load capacity at the neighbour node; and

the second management element is coupled to the load information element and to the parameter set and is arranged to compare the current load experienced by the neighbour node and a load threshold parameter and to send load notifications to network nodes in the subscription list when the current load is less than the load notification threshold.

34. Apparatus as claimed in claim 33, wherein the parameter set also contains a mode parameter determining a mode of operation of the neighbor node, the second management element being arranged to update the mode parameter in response to a message from a third management element in a operation and maintenance network node.