WO2015058807A1

WO2015058807A1 - Method and apparatus for access selection policy in cellular/non-cellular access system

Info

Publication number: WO2015058807A1
Application number: PCT/EP2013/072351
Authority: WO
Inventors: Istvan Zsolt Kovacs; Per Henrik MICHAELSEN; Daniela Laselva; Lucas GIMENEZ
Original assignee: Nokia Solutions And Networks Oy
Priority date: 2013-10-25
Filing date: 2013-10-25
Publication date: 2015-04-30

Abstract

A method comprises receiving first information, and determining if a user equipment attached to an access node of a cellular network is to initiate traffic to an access point of a wireless local network, said determining comprising using said first information to determine which of a plurality of different rules is to be used and applying said determined rule to a power of a reference signal received from said access node to determine if said user equipment is to be initiate traffic on said access point.

Description

Description Title

METHOD AND APPARATUS FOR ACCESS SELECTION POLICY IN CELLULAR/NON-CELLULAR ACCESS SYSTEM

This disclosure relates to a method and apparatus and in particular but not exclusively to method and apparatus for use in the interworking between a cellular wireless network and wireless local area network.

A communication system can be seen as a facility that enables communication sessions between two or more nodes such as fixed or mobile communication devices, access points such as nodes, base stations, servers, hosts, machine type servers, routers, and so on. A communication system and compatible communicating devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. For example, the standards, specifications and related protocols can define the manner how communication devices shall communicate with the access points, how various aspects of the communications shall be implemented and how the devices and functionalities thereof shall be configured.

A user can access the communication system by means of an appropriate communication device. A communication device of a user is often referred to as user equipment (UE), user device or terminal.

Signals can be carried on wired or wireless carriers. Examples of wireless systems include public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Wireless systems can be divided into coverage areas referred to as cells, such systems being often referred to as cellular systems. A cell can be provided by a wireless access node such as a base station, there being various different types of base stations. Different types of cells can provide different features. For example, cells can have different shapes, sizes, functionalities and other characteristics. A cell is typically controlled by a control node.

A communication device is provided with an appropriate signal receiving and transmitting arrangement for enabling communications with other parties. In wireless systems a communication device typically provides a transceiver station that can communicate with another communication device such as e.g. a base station and/or another user equipment. A communication device such as a user equipment (UE) may access a carrier provided by a base station, and transmit and/or receive on the carrier. An example of cellular communication systems is an architecture that is being standardized by the 3rd Generation Partnership Project (3GPP). A recent development in this field is often referred to as the long-term evolution (LTE) or long-term evolution advanced (LTE advanced) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. In LTE base stations providing the cells are commonly referred to as enhanced NodeBs (eNB). An eNB can provide coverage for an entire cell or similar radio service area.

WLAN networks are becoming an integrated part of mobile broadband. WLAN is a standard feature on some phones such as smart phones, tablets and laptops.

According to an aspect, there is provided a method comprising: receiving first information; and determining if a user equipment attached to an access node of a cellular network is to initiate traffic to an access point of a wireless local network, said determining comprising using said first information to determine which of a plurality of different rules is to be used and applying said determined rule to a power of a reference signal received from said access node to determine if said user equipment is to initiate traffic on said access point.

Each of said plurality of rules may be associated with a given range of values, said determining may comprise determining which of said ranges said first information is in to determine which of said plurality of different rules is to be applied.

The said ranges may be non-overlapping.

Each of said rules may define how said power of said reference value is to be compared to a value defined by said first information.

The first information may comprise a threshold reference signal power value.

At least one rule may comprise determining if said power of said reference value exceeds value defined by said first information.

The at least one rule may comprise determining if said power of said reference value is less than a value defined by said first information.

The cellular network may comprise a 3GPP LTE network and the wireless local network may be an IEEE network.

The method may comprise receiving said first information from one of said cellular network and wireless local network.

A user equipment may be configured to perform any of the above methods.

According to an aspect, there is provided an apparatus comprising: means for receiving first information; and means for determining if a user equipment attached to an access node of a cellular network is to initiate traffic to an access point of a wireless local network, said determining means using said first information to determine which of a plurality of different rules is to be used and applying said determined rule to a power of a reference signal received from said access node to determine if said user equipment is to initiate traffic on said access point.

Each of said plurality of rules may be associated with a given range of values, said determining means may be for determining which of said ranges said first information is in to determine which of said plurality of different rules is to be applied.

The said ranges may be non-overlapping.

The first information may comprise a threshold reference signal power value.

At least one rule may comprise determining if said power of said reference value exceeds a value defined by said first information.

At least one rule may comprise determining if said power of said reference value is less than a value defined by said first information.

The receiving means may be for receiving said first information from one of said cellular network and wireless local network.

The apparatus may be provided in a user equipment.

According to another aspect, there is provided apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: receive first information; and

determine if a user equipment attached to an access node of a cellular network is to initiate traffic to an access point of a wireless local network, said determining comprising using said first information to determine which of a plurality of different rules is to be used and applying said determined rule to a power of a reference signal received from said access node to determine if said user equipment is to initiate traffic on said access point.

Each of said plurality of rules may be associated with a given range of values, and the at least one memory and the computer code may be configured, with the at least one processor, to determine which of said ranges said first information is in to determine which of said plurality of different rules is to be applied.

The ranges may be are non-overlapping.

The first information may comprise a threshold reference signal power value.

At least one rule may comprises determining if said power of said reference value exceeds value defined by said first information. At least one rule may comprise determining if said power of said reference value is less than a value defined by said first information.

The cellular network may be a 3GPP LTE network and the wireless local network is an IEEE network.

The at least one memory and the computer code may be configured, with the at least one processor, to receive said first information from one of said cellular network and wireless local network.

The apparatus may be provided in a user equipment.

According to an aspect, there is provided a method comprising: causing first information to be transmitted to a user equipment attached to an access node of a cellular network, said first information being used by said user equipment to determine which of a plurality of different rules is to be applied to a received power of a reference signal to determine if said user equipment is to initiate traffic on an access point of a wireless local network.

The method may be performed in said access node or said access point.

According to an aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: cause first information to be transmitted to a user equipment attached to an access node of a cellular network, said first information being used by said user equipment to determine which of a plurality of different rules is to be applied to a received power of a reference signal to determine if said user equipment is to initiate traffic on an access point of a wireless local network.

The apparatus may be provided in the access point or the access node.

According to an aspect, there is provided an apparatus comprising: means for causing first information to be transmitted to a user equipment attached to an access node of a cellular network, said first information being used by said user equipment to determine which of a plurality of different rules is to be applied to a received power of a reference signal to determine if said user equipment is to initiate traffic on an access point of a wireless local network.

The apparatus may be provided in said access node or said access point.

A computer program comprising program code means adapted to perform the method(s) may also be provided. The computer program may be stored and/or otherwise embodied by means of a carrier medium.

In the above, many different embodiments have been described. It should be appreciated that further embodiments may be provided by the combination of any two or more of the embodiments described above. Various other aspects and further embodiments are also described in the following detailed description and in the attached claims.

Embodiments may combine one or more features from one or more aspects. Various other aspects and further embodiments are also described in the following detailed description and in the attached claims.

Embodiments will now be described in further detail, by way of example only, with reference to the following examples and accompanying drawings, in which:

Figure 1 shows an architecture with a WLAN and a wireless cellular network;

Figure 2 shows a user equipment;

Figure 3 shows a control apparatus;

Figure 4 shows a non-collocated deployment of a base station and WLAN node;

Figure 5 shows a collocated deployment of a base station and WLAN node;

Figure 6 schematically shows a collocated deployment of a base station and WLAN node according to some embodiments;

Figure 7 schematically shows base station/WLAN selection rules of some embodiments; and

Figure 8 shows a method of some embodiments.

Reference numerals refer to the same element throughout the description and figures.

WLAN networks are in some places becoming an integral part of mobile broadband. WLAN is a standard feature on some smart phones, tablets and laptops. Some operators are using or planning to use WLAN alongside mobile radio access networks. As WLAN becomes just another cell alongside mobile radio access networks, some operators need to control how the user device or user equipment moves between the mobile and WLAN networks.

Mobile network operators are thus using cellular offloading to (carrier/third parties) WLAN networks for capacity and coverage purposes. The use of WLAN networks may be inexpensive in terms of licensing for spectrum and/or for cost of deployment). WLAN networks may offer good network performance in high-traffic urban environments.

Furthermore, even without any operator control, today's subscribers simply disappear from cellular networks to connect to the user's preferred access points whenever these are available, e.g. at home or in the work place. That is because WLAN network discovery, selection and access is terminal implementation specific and may further be user-controlled via a connection manager utility installed at the client side. This may provide ad-hoc connectivity.

Reference is made to Figure 1 which shows a high level network architecture example with an ANDSF server. The system shown in Figure 1 comprises user equipment 14. The user equipment is arranged to be able to connect to a first access point or a second access point 6 or 8. As an example, the access points 6 and 8 are connected to a router 4 which permits connection to the Internet 2. The access points 6 and 8 along with the router 4 can be considered to provide the WLAN function. The access points may be part of a WLAN. In some embodiments, the access points may belong to different WLANs. In practice, there are multiple deployment possibilities for WLAN. In operator cases, there may be a WLAN Controller to which access are connected. The WLAN Controller is then attached to operator backbone, in practice at least to a router providing access to the Internet.

The user equipment 14 is also arranged to be able to connect to an access node

15 of a radio access network. The access node 15 may be a base station, node B or the like. Also provided is a RAN controller 16, in some embodiments. The RAN is made up of the base station or node B and the controller. In some embodiments, the controller and the access node may be provided by a common entity such as an eNodeB.

Also shown is an ANDSF server 12 which is connected using either a 3GPP or non

3GPP IP access to the UE. The ANDSF server is an approach to providing overall and fixed network selection policies to a user device. These policies may include for example the roaming partner WLAN networks the user device should utilize when available, overall network selection policies for operator hotspots, and default network discovery and selection rules for the UE.

In other embodiments, alternatively or additionally ANDSF related functionality may be placed elsewhere in the network, such as the packet core and P-GW/DPI (Packet gateway/Deep Packet Inspection or PCRF (Policy and Charging Rules Function, like PCRF-ANDSF).

A possible mobile communication device suitable for implementing some embodiments will now be described in more detail in reference to Figure 2 showing a schematic, partially sectioned view of a communication device 200. Such a communication device is often referred to as user equipment (UE) or terminal. An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) such as a mobile phone or what is known as a 'smart phone', a computer provided with a wireless interface card, USB stick or 'dongle' with radio, or other wireless interface facility, personal data assistant (PDA) provided with wireless communication capabilities, or any combinations of these or the like. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non-limiting examples of the content include downloads, television and radio programs, videos, advertisements, various alerts and other information.

The mobile device 200 may receive signals over an air interface 207 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 2 transceiver apparatus is designated schematically by block 206. The transceiver apparatus 206 may be provided for example by means of a radio part and associated antenna arrangement. The radio part may be arranged to communicate simultaneously with different stations. The radio part may also be arranged to communicate via different radio technologies. For example, the radio part can provide a plurality of different radios. The antenna arrangement may be arranged internally or externally to the mobile device.

A mobile device is also typically provided with at least one data processing entity

201 such as a processor, at least one memory 202 and other possible components 203 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 204. The at least one memory may be implemented as at least one memory unit within the processor or externally to the processor. In the latter case it may be communicatively coupled to the processor via various means, as is known in the art. The mobile communication device may also use cloud services.

The user may control the operation of the mobile device by means of a suitable user interface such as key pad 205, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 208, a speaker and a microphone can be also provided. Furthermore, a mobile communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

The communication devices can access the communication system based on various access techniques, such as 3GPP standardized Long Term Evolution (LTE), Code Division Multiple Access (CDMA), or Wideband CDMA (WCDMA). Other examples include Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA) and various schemes thereof such as the Interleaved Frequency Division Multiple Access (I FDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA) and Orthogonal Frequency Division Multiple Access (OFDMA), Space Division Multiple Access (SDMA) and so on. Some communication devices can in addition also access local area or wide area communications systems based on various non-3GPP standardized access techniques such as Wireless Local Area Network (WLAN) and/or WiMax (Worldwide Interoperability for Microwave Access) and/or HRPD (High Rate Packet Data, commonly known as 1xEV-DO).

Further development of the LTE is referred to as LTE-Advanced. Non-limiting examples of appropriate LTE access nodes are a base station of a cellular system, for example what is known as evolved NodeB (eNB) in the vocabulary of the 3GPP specifications.

One or more entities of the RAN may be provided with a control apparatus. Figure

3 shows an example of a control apparatus. The control apparatus 300 can be configured to provide control functions. For this purpose the control apparatus 300 comprises at least one memory 301 , at least one data processing unit 302, 303 and an input/output interface 304. Via the interface the control apparatus can be coupled to receive information and/or commands and/or provide as output information and/or commands. The control apparatus 300 can be configured to execute an appropriate software code to provide the control functions. The components/facilities may be software, hardware or combinations thereof. It will be understood that within the apparatus 300 the data processing unit and memory may be implemented in one or more physical or logical entities.

In some situations, operator of a cellular network may have limited control over the offload to WLAN and this may lead to degraded user experience (quality of service/quality of experience QoS/QoE) when for example the WLAN experiences high load and/or poor coverage conditions. In some situations, operators of cellular networks may benefit from increased network control over the mechanisms to steer user equipment between the cellular network and the WLAN and/or from more dynamic mechanisms based on, for example, one or more of current network loading, an application's QoS requirements, and RF conditions of the user equipment.

Some offloading mechanisms are being proposed in the context of standards bodies, including 3GPP and WLAN Alliance. HotSpot 2.0, for example, enables the automatic discovery of WLAN networks but addresses mainly WLAN players

It has been suggested a have a connection mode access selection solution for WLAN/3GPP radio interworking utilizing 3GPP RSRP (reference signal received power), WLAN RSSI (received signal strength indicator) and WLAN BSS (base station system) load threshold parameters.

It has been suggested to have an idle mode access selection for WLAN/3GPP radio interworking and utilise broadcast information about the network status as network assistance for a UE to perform access selection decision in line with the existing 3GPP principles for idle mode cell reselection.

It has been suggested to have the same solution for UEs in an idle mode and a connected mode, i.e. for offloading to and from the WLAN based on the UE estimates of the maximum achievable rate for all the networks to which the UE can connect. The estimate maybe based on the measurements the UE performs and the assistance information broadcast by the network.

It has been suggested to have an offloading procedure for an idle mode UE. Offloading for an RRC idle mode UE may use a method that makes a UE prepared for connecting to a WiFi cell instead of a cellular cell when data or signalling is ready to be transmitted in the idle mode.

Generally the above suggestions use, in one way or other, the WLAN RSSI measurement as an underlying information source for performing the network selection. These suggestions make the assumption that the WLAN RSSI estimation is as reliable as LTE RSRP. However, this is flawed. In the current WLAN implementations the RSSI measurement and estimation is not specified by the standards nor is part of the WLAN Alliance certification. WLAN RSS measures in WLAN devices may be inconsistent across different UE devices.

Reference is now made to Figure 4 which shows a non-collocated LTE and WLAN deployment scenario. A base station 103 is provided in a different location to the WLAN access node 102. A cell is schematically represented by reference 100. The RSRP-based mechanism determines the area/locations where UEs are targeted for offloading to WLAN. The UE will be served by the WLAN access node when in region 105. This is where RSRP < Th_rsrp and RSSI > Th_rssi. There is an uncertainty area 106 due to inaccurate RSS estimation in the UEs around region 105. When the threshold condition is not met the UEs are assumed to be served by the non-collocated LTE cell. The area border for RSRP < Th_rsrp is schematically shown by reference 108. The use of the RSRP-based mechanism or rule is shown to provide most of the gain when the targeted offloading is from a LTE cell to a non-collocated WLAN AP.

Reference is now made to Figure 5 which shows a collocated LTE and WLAN deployment scenario. The LTE base station 103 and WLAN access point 102 are located at more or less the same place. The effect of applying the same RSRP-based rule as described in relation to Figure 4 will now be considered. UEs are served by WLAN in locations with RSRP < Th_rsrp AND RSSI > Th_rssi. This area is referenced 105. The uncertainty area 106 due to inaccurate RSSI estimation in the UEs surrounds area 105. The area border 108 for RSRP < Th_rsrp provides the inner border for area 105. When the RSRP and RSSI threshold conditions are not met the UEs are assumed to be served by the collocated LTE cell. Poor utilisation of both WLAN and LTE cell capacities may be achieved in this scenario.

The RSSI-based mechanism may be beneficial when the targeted offloading is from a cell, which may be a micro cell or any other suitable cell, to a collocated WLAN AP (access point). However, in a LTE and WLAN collocated deployment scenario applying the same RSRP-based rule as in the non-collocated deployment may lead to a poor utilisation of both WLAN and LTE cell capacities. This may lead to a sub-optimal system performance.

Some embodiments may provide a mechanism which makes the RSRP-based mechanism beneficial in any deployment scenario i.e. both collocated and non-collocated. Some embodiments may remove the need to use any explicit RSSI -based rules for offloading UEs to the WLAN. In some embodiments, for a collocated cell the LTE RSRP measurements can also be used to achieve approximately the same effect as when using the RSS-based mechanism. Thus in some embodiments a "RSRP > Th_rsrp" rule is used. By using this RSRP rule the drawbacks of the suggested offloading rules shown in Figure 5, may be reduced or avoided in some embodiments.

The 3GPP defined RSRP measurement is a physical layer measurement made by a UE. It is a linear average of the downlink reference signals (RS) across a channel bandwidth. The RS are provided for one symbol. The measurement is made on those resource elements RE that contain cell-specific RS. The RSRP may provide the UE with information about the strength of cells from which path loss can be calculated and used to determine power. This may be consistently applied across UEs as the mechanism for providing RSRP measurements may be defined in a standard or the like.

Reference is made to Figure 6 which schematically shows embodiment. In this Figure, a collocated LTE and WLAN deployment scenario is shown. The base station 103 and WLAN access point 102 are collocated. As compared to the arrangement of Figure 5, the RRSI threshold parameter has been replaced by an equivalent RSRP threshold parameter to control and/or select the WLAN offloading area. UEs are served by WiFi in locations 1 10 with RSRP > Th_rsrp. In both cases, when the threshold conditions are not met the UEs are assumed to be served by the collocated LTE cell. Significantly better utilisation of both WLAN and LTE cell capacities may be achieved compared to the arrangement of Figure 5.

Some embodiments fit into, but are not limited to, the overall flow-chart proposed for 3GPP-WLAN interworking.

Reference will be made to Figure 7 which schematically illustrates an embodiment and Figure 8 which shows a method. Figure 7 shows an example of two rules selection options based on two different Th_rsrp parameters signalled to the UE. Two offloading rules options are mapped to the corresponding two Th_rsrp parameters. A first range of values is associated with Th_rsrp1 and a second range of values is associated with Th_rsrp2. When the RSRP threshold value signalled to the UE, Th_rsrp is within the range associated with Th_rsrp1, then UE applies the rule "RSRP < Th_rsrp" to decide whether to connect to WLAN or 3GPP cell. When the RSRP threshold value signalled to the UE, Th_rsrp is within the range associated with Th_rsrp2, then UE applies the rule "RSRP > Th_rsrp" to decide whether to connect to WLAN or 3GPP cell. Thus the Th_rsrp is signalled to the UE and the UE decides which rule to apply according to the detected value range of the Th_rsrp.

. An example is given as follows with two UE1 and UE2 served by two different LTE cells BS1 and BS2 respectively. For simplicity the RSRP values in dBm units are used but the same functionality can be achieved by employing corresponding RSRP indices as for example defined in the 3GPP specifications. The Th_rsrp1 and Th_rsrp2 ranges are defined as -90dBm to -70dBm and -70dBm to -40dBm, respectively. The serving cell BS1 provides via e.g., signalling or broadcasting, the RSRP threshold Th_rsrp = -75dBm to the UE1 . The serving cell BS2 provides via e.g., signalling or broadcasting, the RSRP threshold Th_rsrp = -65dBm to the UE2. If for example the first UE, UE1 , estimates an RSRP towards its serving cell BS1 of RSRP_UE1=-76dBm. The UE1 determines that the signalled Th_rsrp values is in the Th_rsrp1 range, therefore it applies the rule "RSRP_UE1 < -75dBm (This is described later with respect to step S5 of Figure 8) and determines that it can initiate the offload to the WLAN according to one or more other potential offloading rules provided (This is describe later with respect to step S6 of Figure 8). If for example the second UE, UE2, estimates an RSRP towards its serving cell BS2 of RSRP_UE2 =- 69dBm. The UE2 determines that the signalled Th_rsrp values is in the Th_rsrp2 range, therefore it applies the rule "RSRP_UE2 > -65dBm" (This is described later with respect to step S7 of Figure 8) and determines that it cannot initiate offload to WLAN and should initiate or maintain connection to the LTE network (This is described later with respect to step S8 of Figure 8).

A second example is given as follows with two UE1 and UE2 served by the same LTE cell, where two threshold values are provided to the served UEs. For simplicity the RSRP values in dBm units are used but the same functionality can be achieved by employing corresponding RSRP indices as for example defined in the 3GPP specifications. The Th_rsrp1 and Th_rsrp2 ranges are defined as -90dBm to -70dBm and - 70dBm to -40dBm, respectively. The serving LTE cell provides via e.g., signalling or broadcasting, the RSRP thresholds Th_rsrp_1 = -85dBm and Th_rsrp_2 = -65dBm. Foror example the first UE, UE1 , estimates an RSRP towards its serving cell of RSRP_UE1=- 86dBm. The UE1 determines that the signalled Th_rsrp_1 value is in the Th_rsrp1 range, and therefore the UE applies the rule "RSRP_UE1 < -85dBm" and determines that it can initiate the offload to the WLAN according to one or more other potential offloading rules provided. For example the second UE, UE2, estimates an RSRP towards its serving cell of RSRP_UE2=-60dBm. The UE2 determines that the signalled Th_rsrp_2 value is in the Th_rsrp2 range, and therefore the UE applies the rule "RSRP_UE2 > -65dBm" and determines that the UE can initiate the offload to the WLAN according to one or more other potential offloading rules provided.

In some embodiment an RSRP-based threshold or corresponding index in a mapping table, Th_rsrp, is selected by one or more of a control apparatus such as shown in Figure 3 of a RAN, ANDSF and/or or other provisioning mechanisms for a given cellular network. The threshold value may depend on one or more cellular network KPIs (key performance indicators), such as but not limited to cell load, number of UEs served, type of traffic served. This threshold value may in addition depend on any one or more WLAN measurements and/or WLAN system KPIs when/if available, such as but not limited to BSS load, WLAN throughput, number of UEs connected to WLAN.

With reference to Figure 8, in some embodiments, a UE is provided in step S1 with one threshold value, Th_rsrp. The signalled threshold is used in the corresponding RSRP rule. The UE may be provided with the thresholds via one of RAN SIB (signal indicator bit), RAN RRC (radio resource control) dedicated signalling, ANDSF or any other provisioning mechanism.

In some embodiments, the UEs are default/pre-configured with the rules and thresholds. In this case step S1 may be omitted.

In some embodiments, the UE may have the rules already (due to a default or prior configuration) and in step S1 only information defining the thresholds need to be signalled.

In some embodiments, the information defining the thresholds and information defining the rules may be signalled to the UE either at the same time or at different times.

In or explicitly configured (e.g. via ANDSF) with at least one offloading rules set which utilises the two (or more) signalled Th_rsrp values and takes into consideration the rule selection options as exemplified in Figure 4.

In some embodiments, the UE is provided with the thresholds themselves. In other embodiments, the UE is provided with information which allows the thresholds to be determined. For example the information may be to a particular entry in a look up table or may be information which is used in an algorithm to determine the thresholds or any other suitable information.

In step S2, the UE determines if a WLAN is on.

If so, the next step is step S3 in which the UE will build a BSSID list of available and allowed WLAN access points. It should be appreciated that in alternative embodiments, the UE may receive a list of one or more access points from the base station.

In step S4, the WTSI (WLAN Traffic Steering Indicator traffic steering indicator) is signalled to the UE from the RAN.

In step S5, it is determined if a Th_rsrp value in the Th_rsrp1 range is signalled and if RSRP <Th_rsrp.

If so, the next step is step S6 in which offload to the WLAN AP is initiated. This may be to the WLAN AP with the current BSSID. This may optionally take into account ANDSF and/or other WLAN settings, such as WLAN priorities, WLAN BSS load.

If not, the next step is S7 in which it is determined if a Th_rsrp value in the

Th_rsrp2 range is signalled and if RSRP >Th_rsrp.

If so, the next step is step S6 as discussed previously.

In not, the next step is step S8 where there may be cellular traffic steering or the status quo is maintained.

In some embodiments, steps S5 and S7 may be combined or carried out in any order.

In some embodiments two thresholds are signalled/provided to the UE.

In some embodiments, the ranges are non-overlapping. In other embodiments, the ranges may be overlapping, but there may be a need for another measure and/or parameter/information to decide which rule to apply

Some embodiments may have one or more of the following advantages:

Use of standardised RSRP measurements only.

Ensures consistent behaviour, regardless of the UE WLAN RSSI estimation procedures;

LTE cell specific settings can be provided, thus the offloading effect may be be easily controlled (for example via a self-organising network SON ) in different geographical and coverage areas, including various WLAN AP deployment cases (located or non-collocated, or mixture of); and

The mechanism can be accommodated without difficult in current 3GPP-WLAn inter-working proposals.

Some examples have a 3GPP cellular network and an IEEE standard WLAN.

In some embodiments the threshold information is provided for (but not necessarily by) the system on which the target UE can do the most reliable and consistent signal power measurement (of a reference signals) and apply the selected rule(s).

Embodiments have been described in relation to WLAN and RAN networks. It should be appreciated that these two networks are by way of example only. In some embodiments, other cellular communication networks may be used instead of RAN networks. In particular some embodiments may be used with networks other than 3GPP LTE networks. Other suitable wireless local networks can be used instead of the WLAN network. Some embodiments may be used with any two or more suitable networks.

As the embodiments have been described with reference to a LTE or similar network, reference has been made to RSRP measurements. It should be appreciated that any other suitable measurement may be used where a reference signal or symbol is transmitted with a known power by an access node to a user equipment and the user equipment is able to measure the power at which the reference signal is received. In some embodiments the user equipment is able to consistently and with a required absolute accuracy measure the power at which the reference signal is received.

In the above embodiments, a comparison is described as being made with the RSRP or the like. It should be appreciated that in some embodiments, the comparison may be with information which is derived or dependent on the RSRP.

The required data processing apparatus and functions of an apparatus in a network element and/or a mobile device for the causing configuration, signalling, determinations, and/or control of measurement and reporting and so forth may be provided by means of one or more data processor. The described functions may be provided by separate processors or by an integrated processor. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non-limiting examples or suitable circuitry. The data processing may be distributed across several data processing modules. A data processor may be provided by means of, for example, at least one chip. Appropriate memory capacity can also be provided in the relevant devices. The memory or memories may be of any circuitry type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory.

An appropriately adapted computer program code product or products may be used for implementing the embodiments, when loaded or otherwise provided on an appropriate data processing apparatus. The program code product for providing the operation may be stored on, provided and embodied by means of an appropriate carrier medium. An appropriate computer program can be embodied on a computer readable record medium. A possibility is to download the program code product via a data network. In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Embodiments may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large an automated process. Complex and powerful tools are available for converting a logic level design into a semiconductor circuit design ready to be formed on a semiconductor substrate.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of some embodiments. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. For example, a combination of one or more of any of the other embodiments previously discussed can be provided.

All such and similar modifications will still fall within the scope of this invention as defined in the appended claims.

Various modifications to the embodiments described above will readily occur to the skilled person. The invention is not limited to theses specific examples.

Claims

Claims:

1. A method comprising:

receiving first information; and

determining if a user equipment attached to an access node of a cellular network is to initiate traffic to an access point of a wireless local network, said determining comprising using said first information to determine which of a plurality of different rules is to be used and applying said determined rule to a power of a reference signal received from said access node to determine if said user equipment is to initiate traffic on said access point.

2. A method as claimed in claim 1 , wherein each of said plurality of rules is associated with a given range of values, said determining comprising determining which of said ranges said first information is in to determine which of said plurality of different rules is to be applied.

3. A method as claimed in claim 1 or 2, wherein said ranges are non-overlapping.

4. A method as claimed in any preceding claim, wherein each of said rules defines how said power of said reference value is to be compared to a value defined by said first information.

5. A method as claimed in any preceding claim, wherein said first information comprises a threshold reference signal power value.

6. A method as claimed in any preceding claim, wherein at least one rule comprises determining if said power of said reference value exceeds value defined by said first information.

7. A method as claimed in any preceding claim, wherein at least one rule comprises determining if said power of said reference value is less than a value defined by said first information.

8. A method as claimed in any preceding claim, wherein said cellular network is a 3GPP LTE network and the wireless local network is an IEEE network.

9. A method as claimed in any preceding claim, comprising receiving said first information from one of said cellular network and wireless local network.

10. A method comprising:

causing first information to be transmitted to a user equipment attached to an access node of a cellular network, said first information being used by said user equipment to determine which of a plurality of different rules is to be applied to a power of a reference signal to determine if said user equipment is to initiate traffic on an access point of a wireless local network.

1 1. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to:

receive first information; and

12. An apparatus as claimed in claim 1 1 , wherein each of said plurality of rules is associated with a given range of values, and the at least one memory and the computer code are configured, with the at least one processor, to determine which of said ranges said first information is in to determine which of said plurality of different rules is to be applied.

13. An apparatus as claimed in claim 1 1 or 12, wherein said ranges are non- overlapping.

14. An apparatus as claimed in any of claims 1 1 to 13, wherein each of said rules defines how said power of said reference value is to be compared to a value defined by said first information.

15. An apparatus as claimed in any of claims 1 1 to 14, wherein said first information comprises a threshold reference signal power value.

16. An apparatus as claimed in any of claims 1 1 to 15, wherein at least one rule comprises determining if said power of said reference value exceeds value defined by said first information.

17. An apparatus as claimed in any of claims 1 1 to 16, wherein at least one rule comprise determining if said power of said reference value is less than a value defined by said first information.

18. An apparatus as claimed in any of claims 1 1 to 17, wherein said cellular network is a 3GPP LTE network and the wireless local network is an IEEE network.

19. An apparatus as claimed in any of claims 1 1 to 18, wherein the at least one memory and the computer code are configured, with the at least one processor, to receive said first information from one of said cellular network and wireless local network.

20. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to:

cause first information to be transmitted to a user equipment attached to an access node of a cellular network, said first information being used by said user equipment to determine which of a plurality of different rules is to be applied to a received power of a reference signal to determine if said user equipment is to initiate traffic on an access point of a wireless local network.

21. A computer program comprising program code means adapted to perform the method of any of claims 1 to 10.