COMMUNICATION SYSTEM

Technical Field:

The present invention relates to mobile telecommunication networks, particularly but not exclusively networks operating according to the 3rd Generation Partnership Project (3GPP) standards or equivalents or derivatives thereof. The invention has particular although not exclusive relevance to the use of carrier aggregation by base stations operating cells as open access mode, closed access mode, or hybrid access mode cells.

Background Art:

Under the 3 GPP standards, a NodeB (or an eNodeB/eNB in the case of the so called 'Long Term Evolution' or 'LTE') is a base station via which mobile devices connect to the core network. Historically, base stations comprised 'macro' base stations which provide

communication cells having a relatively large geographical coverage. More recently, however, base stations having a more limited geographical coverage have also been standardised to provide improved coverage in geographical areas where a macro base station's coverage is known to deteriorate and/or to provide additional services targeted at specific users or groups of users.

Specifically, for example, the 3GPP standards body has adopted a standard for so called 'home' or 'femto' base stations which provide so called 'femto' cells having a relatively limited geographical coverage. Where the home base station is operating in accordance with the LTE standards, it is sometimes referred to as a HeNB. The home base station is also sometimes referred to as a femto cell, especially in the case of the so called WiMAX network. Typically, a home base station provides a radio coverage (for example, 3 G/4G/WiMAX) within a limited geographical area, often within a building, for example in a home, a small or medium sized enterprise, a shopping mall etc., and connects to a core network via a suitable public network (for example via an ADSL link to the Internet) or operator network.

Optionally, the radio coverage provided by the home base stations may be supported via a 'home (e)NodeB gateway' (HNB-GW) which typically aggregates traffic from several home base stations and handles communication between the home base station(s) and at least one mobility management entity (MME) in the core network. The HNB-GW is, in effect, transparent

to the MME and the home base station with the HNB-GW appearing to be a mobility management entity (MME) from the perspective of the home base station, and to be a standard base station from the perspective of the mobility management entity (MME).

A home base station can generally be configured according to any of the following access modes:

a 'closed' access mode in which the home base station operates a closed subscriber group (CSG) cell to which only members of the CSG may be provided access;

a 'hybrid' access mode in which the home base station operates a CSG cell to which members of the CSG may be provided preferential access whilst non-members are allowed non-preferential (non-CSG) access (for example with a different charging structure, with a different level of service, and/or subject to CSG members being able to successfully access the cell during high load scenarios); and

an 'open' access mode in which the home base station operates as a normal (non-CSG) cell to which access is provided openly.

It has also been decided, as part of the 3 GPP standardisation process, that downlink operation for system bandwidths beyond 20MHz will be based on the aggregation of a plurality of component carriers at different frequencies (this is referred to as carrier aggregation). Such carrier aggregation can be used to support operation in a system both with and without a contiguous spectrum (for example, a non-contiguous system may comprise component carriers at 800MHz, 2GHz, and 3.5GHz).

Carrier aggregation can be particularly beneficial in a heterogeneous network (HetNet), even when the system bandwidth is contiguous, and does not exceed 20 MHz because multiple carriers enable interference management between different classes of cells (e.g. between a macro cell of a macro base station and femto cells operated by a home base station) and also between open access, hybrid and closed subscriber group (CSG) cells operating in the same geographical vicinity.

In accordance with carrier aggregation, therefore, a macro or home base station can operate a first 'primary' cell (PCell) using a first component carrier and at least one further 'secondary' cell (SCell) on a further component carrier. Further, in accordance with operation of home base stations, a home base station can operate a PCell using a first component carrier and having a first access mode (closed, hybrid or open) and an SCell using a second component carrier and having a second access mode (closed, hybrid or open), which second access mode may be different to the first access mode. A home base station can also operate a PCell having a hybrid or closed access mode with an associated first CSG comprising a first set of members and an SCell having a hybrid or closed access mode an associated second CSG comprising a second set of members, which second set of members may be different to said first set of members.

Thus, the use of open, hybrid, and closed access mode cells, in combination with carrier aggregation, has the potential to provide an operator of a home base station with great flexibility to operate different cells for different groups of subscribers - potentially with different charging policies for each cell. For example, a home base station operator could, theoretically, set up their home base station to provide a PCell to a relatively large CSG having a relatively large number of members, and an SCell to a smaller CSG, comprising a subset of the relatively large CSG (e.g. whose members are willing to pay a premium to have access to the additional resources of the SCell). Several other similar scenarios are, of course, possible with different cells (primary or secondary) serving distinct or overlapping subscriber groups or with one cell serving any user (i.e. open access mode), another serving only members of a particular CSG (i.e. closed access mode), and/or another serving members of the CSG preferentially (i.e. hybrid access mode) but allowing other users in when sufficient resources/quality of service are available.

However, there are still a number of technical issues with the use of open, hybrid, and closed access mode cells, in combination with carrier aggregation, which need to be addressed if the above flexibility is to be fully realised. Firstly, for example, the aggregation of one component carrier with one or more others to provide a PCell and one or more SCells is based on radio conditions. Hence, a home base station that operates a PCell and an SCell may make a decision to initiate the configuration of user equipment that is connected via the PCell for use of the SCell (referred to as SCell addition) based on radio condition alone (e.g. responsive to a measurement report from the user equipment. Thus the user equipment of a subscriber to a CSG of a closed/hybrid access mode PCell may be configured to use a closed access mode SCell having a CSG to which the user is not a subscriber.

Another potential issue arises when the different cells (PCell / SCell(s)) via which the user equipment is connected (or is about to be configured to use) have different respective CSGs for which different respective charging structures apply. In this situation, there is currently no efficient way to determine which charging structure should take precedence over another, and a user is unaware of how conflicts of charging structure will be dealt with (e.g. will they be charged the maximum or minimum charge that applies across all the cells of the aggregated component carriers).

Yet another potential issue may arise, for example, when a home base station operates a closed/hybrid access mode PCell having a first CSG, and a closed/hybrid access mode SCell having a second CSG, and the user equipment of a subscriber to both the first CSG and the

second CSG is connected in the PCell and the SCell. In this situation, if the subscriber's subscription to one of the CSGs expires, whilst the other remains valid, the component carrier (cell) configuration in the subscriber's user equipment no longer complies with a valid CSG list and the user equipment may continue to use resources of a CSG of which the subscriber is no longer a member (a similar issue arises when user equipment is connected to a plurality of SCells and a CSG subscription expires in respect of one of those SCells).

Moreover, when a handover is required from a source home base station operating primary and secondary cells having a first set of CSGs, to a target home base station operating primary and secondary cells having a different set of CSGs, there are potential issues in how such a handover can be accomplished efficiently whilst maintaining appropriate access controls and membership checks.

Summary:

Accordingly, exemplary embodiments of the present invention aim to provide methods and apparatus which at least partially address one or more of the above issues.

According to one aspect of the present invention, there is provided communication apparatus for a cellular communication system, the communication apparatus comprising: means for operating a first cell using a first component carrier and at least one further cell using a further component carrier; means for communicating with a mobile communication device operating in said first cell; means for determining that an attempt should be made to configure said mobile communication device to communicate using the at least one further cell; and means for transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using the at least one further cell should be allowed; means for receiving, from the communication entity, a message indicating, for each further cell, whether configuration of said mobile communication device to communicate using that further cell should be allowed; and means for communicating with said mobile communication device to configure said mobile communication device to communicate using each further cell for which a respective indication that such configuration should be allowed has been received such that said mobile

communication device is configured to communicate using each further cell for which a respective indication that such configuration should be allowed has been received, and said mobile communication device is not configured to communicate using each further cell for which a respective indication that such configuration should be allowed has not been received.

According to one aspect of the present invention, there is provided a communication

entity of a cellular communication system in which communication apparatus operates each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined, the communication entity comprising: means for receiving a message to initiate a procedure for checking whether configuration of a mobile communication device to communicate using any of said cells should be allowed, said message comprising information identifying the CSG for each of the plurality of cells for which a closed subscriber group (CSG) has been defined; means for determining, for each of said cells, whether configuration of a mobile communication device to communicate using said cell should be allowed; and means for generating and transmitting a message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed.

According to one aspect of the present invention, there is provided communication apparatus for a cellular communication system, the communication apparatus comprising: means for communicating with a mobile communication device; means for determining that an attempt should be made to handover communication with said communication device from said communication apparatus to target communication apparatus; means for receiving an indication that said target communication apparatus operates a plurality of target cells each using a different respective component carrier, wherein said plurality of said target cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined; means for obtaining an indication for each CSG as to whether or not said mobile communication device is a member of said CSG; means for transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using any of said target cells should be allowed, said message comprising information identifying each CSG for which a respective indication that said mobile

communication device is a member has been obtained; and means for communicating with said mobile communication device to complete said handover procedure for each said target cell for which configuration of said mobile communication device to communicate using that target cell is allowable.

According to one aspect of the present invention, there is provided communication apparatus for a cellular communication system, the communication apparatus comprising: means for operating each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises at least one cell for which a closed subscriber group (CSG) has been defined; means for communicating with a mobile communication device operating in at least one said cell for which a CSG has been defined of which the mobile communication device

is a member; means for obtaining an indication that CSG membership of at least one cell in which the mobile communication device is operating has expired for said mobile communication device; and means for ceasing CSG based communication with said mobile communication device in each said cell for which said CSG membership has expired.

According to one aspect of the present invention, there is provided communication apparatus for a cellular communication system, the communication apparatus comprising: means for operating each of a plurality of cells using a respective component carrier; means for communicating with a mobile communication device; means for transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using at least one of said cells should be allowed; means for receiving, from the communication entity, a message indicating, for each cell represented by the message to initiate a procedure for checking whether configuration of said mobile communication device to communicate using at least one of said cells should be allowed; and means for communicating with said mobile communication device to configure said mobile communication device to communicate using at least one cell for which a respective indication that such configuration should be allowed has been received.

According to one aspect of the present invention, there is provided a mobile

communication device of a cellular communication system in which communication apparatus operates each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined, the mobile communication device comprising: means for receiving from said

communication apparatus information identifying the CSG (CSG ID) for each of said plurality of cells for which a CSG has been defined; means for determining from said received information identifying the CSG for each said cell whether or not said mobile communication device is a member of said CSG; and means for generating and transmitting a message comprising, for each CSG, information identifying the CSG and information indicating the membership of said mobile communication device in said CSG.

According to one aspect of the present invention, there is provided a method performed by communication apparatus for a cellular communication system, the method comprising:

operating a first cell using a first component carrier and at least one further cell using a further component carrier; communicating with a mobile communication device operating in said first cell; determining that an attempt should be made to configure said mobile communication device to communicate using the at least one further cell; and transmitting a message to a

communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using the at least one further cell should be allowed; receiving, from the communication entity, a message indicating, for each further cell, whether configuration of said mobile communication device to communicate using that further cell should be allowed; and communicating with said mobile communication device to configure said mobile communication device to communicate using each further cell for which a respective indication that such configuration should be allowed has been received such that said mobile communication device is configured to communicate using each further cell for which a respective indication that such configuration should be allowed has been received, and said mobile communication device is not configured to communicate using each further cell for which a respective indication that such configuration should be allowed has not been received.

According to one aspect of the present invention, there is provided method performed by a communication entity of a cellular communication system in which communication apparatus operates each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined, the method comprising: receiving a message to initiate a procedure for checking whether configuration of a mobile communication device to communicate using any of said cells should be allowed, said message comprising information identifying the CSG for each of the plurality of cells for which a closed subscriber group (CSG) has been defined; determining, for each of said cells, whether configuration of a mobile communication device to communicate using said cell should be allowed; and generating and transmitting a message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed.

CLAIMS

Communication apparatus for a cellular communication system, the communication apparatus comprising:

means for operating a first cell using a first component carrier and at least one further cell using a further component carrier;

means for communicating with a mobile communication device operating in said first cell;

means for determining that an attempt should be made to configure said mobile communication device to communicate using the at least one further cell; and

means for transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using the at least one further cell should be allowed;

means for receiving, from the communication entity, a message indicating, for each further cell, whether configuration of said mobile communication device to communicate using that further cell should be allowed; and

means for communicating with said mobile communication device to configure said mobile communication device to communicate using each further cell for which a respective indication that such configuration should be allowed has been received such that said mobile communication device is configured to communicate using each further cell for which a respective indication that such configuration should be allowed has been received, and said mobile communication device is not configured to communicate using each further cell for which a respective indication that such configuration should be allowed has not been received.

Communication apparatus according to claim 1 wherein said at least one further cell comprises at least one cell for which a closed subscriber group (CSG) has been defined, and wherein said message to initiate a procedure for checking whether configuration of said mobile communication device to communicate using the at least one further cell should be allowed comprises information identifying the CSG (CSG ID) of at least one said cell for which a closed subscriber group (CSG) has been defined.

Communication apparatus according to claim 2 wherein said at least one cell for which a CSG has been defined comprises at least one closed access mode cell.

Communication apparatus according to claim 2 or 3 wherein said at least one cell for which a CSG has been defined comprises at least one hybrid access mode cell.

Communication apparatus according to claim 4 wherein said message to initiate a procedure for checking whether configuration of said mobile communication device to communicate using the at least one further cell should be allowed comprises information identifying the CSG of each said hybrid access mode cell.

Communication apparatus according to any of claims claim 2 to 5 further comprising means for receiving, from said mobile communication device, a message indicating for each said CSG, whether or not said mobile communication device is a member of said CSG.

Communication apparatus according to claim 6 wherein said message to initiate a procedure for checking whether configuration of said mobile communication device to communicate using the at least one further cell should be allowed comprises information identifying each CSG that said message received from the mobile communication device indicates said mobile communication device is a member of.

Communication apparatus according to any preceding claim wherein said at least on further cell comprises at least one open access mode cell.

Communication apparatus according to any preceding claim wherein said communication entity comprises a mobility management entity (MME).

Communication apparatus according to any preceding claim wherein said communication apparatus comprises a base station.

A communication entity of a cellular communication system in which communication apparatus operates each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined, the communication entity comprising:

means for receiving a message to initiate a procedure for checking whether configuration of a mobile communication device to communicate using any of said cells should be allowed, said message comprising information identifying the CSG for each of the plurality of cells for which a closed subscriber group (CSG) has been defined;

means for determining, for each of said cells, whether configuration of a mobile communication device to communicate using said cell should be allowed;

and means for generating and transmitting a message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed.

A communication entity according to claim 11 wherein said plurality of cells comprises at least one closed access mode cell.

A communication entity according to claim 12 wherein said determining means comprises means for performing an access control procedure for each said closed access mode cell and for determining whether configuration of a mobile communication device to communicate using that cell should be allowed based on said access control procedure. A communication entity according to any of claims 1 1 to 13 wherein said plurality of cells comprises at least one hybrid access mode cell.

A communication entity according to claim 14 wherein said determining means comprises means for performing a membership verification procedure for each hybrid access mode cell (and/or each closed access mode cell) and for determining whether configuration of a mobile communication device to communicate using that cell should be allowed based on said membership verification.

A communication entity according to any of claims 11 to 15 wherein said plurality of cells comprises at least one open access mode cell.

A communication entity according to any of claims 11 to 16 wherein said determining means comprises means for performing an assessment of an operating charging policy for each of said cells and for determining whether configuration of a mobile communication device to communicate using that cell should be allowed based on said charging assessment.

A communication entity according to any of claims 11 to 17 wherein said message to initiate a procedure for checking whether configuration of a mobile communication device to communicate using any of said cells should be allowed comprises an access control request.

A communication entity according to claim 18 wherein said message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed comprises an access control response message.

A communication entity according to any of claims 1 1 to 17 wherein said message to initiate a procedure for checking whether configuration of a mobile communication device to communicate using any of said cells should be allowed comprises a handover message.

A communication entity according to claim 20 wherein said message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed comprises a handover request message.

A communication entity according to any of claims 11 to 21 wherein said generating and transmitting means is operable to transmit said message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed to communication apparatus (e.g. a base station).

A communication entity according to claim 22 wherein said generating and transmitting means is operable to transmit said message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed to a source communication apparatus (e.g. a base station) as part of a handover procedure.

A communication entity according to claim 22 wherein said generating and transmitting means is operable to transmit said message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed to a target communication apparatus (e.g. a base station) as part of a handover procedure.

A communication entity according to claim 22 wherein said generating and transmitting means is operable to transmit said message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed to a communication apparatus (e.g. a base station) as part of a carrier aggregation procedure.

Communication apparatus for a cellular communication system, the communication apparatus comprising:

means for communicating with a mobile communication device;

means for determining that an attempt should be made to handover communication with said communication device from said communication apparatus to target communication apparatus;

means for receiving an indication that said target communication apparatus operates a plurality of target cells each using a different respective component carrier, wherein said plurality of said target cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined;

means for obtaining an indication for each CSG as to whether or not said mobile communication device is a member of said CSG;

means for transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using any of said target cells should be allowed, said message comprising information identifying each CSG for which a respective indication that said mobile communication device is a member has been obtained; and

means for communicating with said mobile communication device to complete said handover procedure for each said target cell for which configuration of said mobile communication device to communicate using that target cell is allowable.

27. Communication apparatus according to claim 26 wherein said receiving means is

operable to receive said indication that said target communication apparatus operates a plurality of target cells each using a different respective component carrier is received from the mobile communication device.

28. Communication apparatus for a cellular communication system, the communication apparatus comprising:

means for operating each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises at least one cell for which a closed subscriber group (CSG) has been defined;

means for communicating with a mobile communication device operating in at least one said cell for which a CSG has been defined of which the mobile communication device is a member;

means for obtaining an indication that CSG membership of at least one cell in which the mobile communication device is operating has expired for said mobile communication device; and

means for ceasing CSG based communication with said mobile communication device in each said cell for which said CSG membership has expired.

29. Communication apparatus according to claim 28 wherein said at least one cell for which said CSG membership has expired comprises a closed access mode cell.

30. Communication apparatus according to claim 28 or 29 wherein said at least one cell for which a CSG has been defined comprises at least one hybrid access mode cell and wherein said means for ceasing CSG based communication is operable to allow said mobile communication device to continue communicating in said at least one hybrid access mode cell as a non-CSG member.

31. Communication apparatus according to any of claims 28 to 30 further comprising means for generating a notification that said CSG based communication with said mobile communication device has ceased in each said cell for which said CSG membership has expired, and for transmitting said notification to a communication entity (e.g. a mobility management entity (MME)) of said communication system.

32. Communication apparatus according to any of claims 28 to 31 wherein said obtaining means is operable to receive said indication that CSG membership of at least one cell in which the mobile communication device is operating has expired for said mobile communication device from a (or the) communication entity (e.g. a mobility management entity (MME)) of said communication system.

Communication apparatus according to any of claims 28 to 30 wherein said means for ceasing CSG based communication is operable to transfer communication with said mobile communication device from said at least one cell for which CSG membership has expired to at least one further of said plurality of cells, responsive to said membership expiry.

Communication apparatus for a cellular communication system, the communication apparatus comprising:

means for operating each of a plurality of cells using a respective component carrier; means for communicating with a mobile communication device;

means for transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using at least one of said cells should be allowed; means for receiving, from the communication entity, a message indicating, for each cell represented by the message to initiate a procedure for checking whether configuration of said mobile communication device to communicate using at least one of said cells should be allowed; and

means for communicating with said mobile communication device to configure said mobile communication device to communicate using at least one cell for which a respective indication that such configuration should be allowed has been received.

A mobile communication device of a cellular communication system in which

communication apparatus operates each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined, the mobile communication device comprising:

means for receiving from said communication apparatus information identifying the CSG (CSG ID) for each of said plurality of cells for which a CSG has been defined;

means for determining from said received information identifying the CSG for each said cell whether or not said mobile communication device is a member of said CSG; and means for generating and transmitting a message comprising, for each CSG, information identifying the CSG and information indicating the membership of said mobile communication device in said CSG.

A method performed by communication apparatus for a cellular communication system, the method comprising:

operating a first cell using a first component carrier and at least one further cell using a further component carrier;

communicating with a mobile communication device operating in said first cell;

determining that an attempt should be made to configure said mobile communication device to communicate using the at least one further cell; and

transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using the at least one further cell should be allowed;

receiving, from the communication entity, a message indicating, for each further cell, whether configuration of said mobile communication device to communicate using that further cell should be allowed; and

communicating with said mobile communication device to configure said mobile communication device to communicate using each further cell for which a respective indication that such configuration should be allowed has been received such that said mobile communication device is configured to communicate using each further cell for which a respective indication that such configuration should be allowed has been received, and said mobile communication device is not configured to communicate using each further cell for which a respective indication that such configuration should be allowed has not been received.

A method performed by a communication entity of a cellular communication system in which communication apparatus operates each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined, the method comprising:

receiving a message to initiate a procedure for checking whether configuration of a mobile communication device to communicate using any of said cells should be allowed, said message comprising information identifying the CSG for each of the plurality of cells for which a closed subscriber group (CSG) has been defined;

determining, for each of said cells, whether configuration of a mobile communication device to communicate using said cell should be allowed; and

generating and transmitting a message indicating for each of said cells whether configuration of said mobile communication device to communicate using that cell should be allowed.

A method performed by communication apparatus for a cellular communication system, the method comprising:

communicating with a mobile communication device;

determining that an attempt should be made to handover communication with said communication device from said communication apparatus to target communication apparatus;

receiving an indication that said target communication apparatus operates a plurality of target cells each using a different respective component carrier, wherein said plurality of said target cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined;

obtaining an indication for each CSG as to whether or not said mobile communication device is a member of said CSG;

transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using any of said target cells should be allowed, said message comprising information identifying each CSG for which a respective indication that said mobile communication device is a member has been obtained; and

communicating with said mobile communication device to complete said handover procedure for each said target cell for which configuration of said mobile communication device to communicate using that target cell is allowable.

A method performed by communication apparatus for a cellular communication system, the method comprising:

operating each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises at least one cell for which a closed subscriber group (CSG) has been defined;

communicating with a mobile communication device operating in at least one said cell for which a CSG has been defined of which the mobile communication device is a member;

obtaining an indication that CSG membership of at least one cell in which the mobile communication device is operating has expired for said mobile communication device; and

ceasing CSG based communication with said mobile communication device in each said cell for which said CSG membership has expired.

A method performed by communication apparatus for a cellular communication system,

the method comprising:

operating each of a plurality of cells using a respective component carrier;

communicating with a mobile communication device;

transmitting a message to a communication entity of said communication system to initiate a procedure for checking whether configuration of said mobile communication device to communicate using at least one of said cells should be allowed;

receiving, from the communication entity, a message indicating, for each cell represented by the message to initiate a procedure for checking whether configuration of said mobile communication device to communicate using at least one of said cells should be allowed; and

communicating with said mobile communication device to configure said mobile communication device to communicate using at least one cell for which a respective indication that such configuration should be allowed has been received.

A method performed by a mobile communication device of a cellular communication system in which communication apparatus operates each of a plurality of cells using a respective component carrier, wherein said plurality of said cells comprises a plurality of cells for which a closed subscriber group (CSG) has been defined, the method

comprising:

receiving from said communication apparatus information identifying the CSG (CSG ID) for each of said plurality of cells for which a CSG has been defined;

determining from said received information identifying the CSG for each said cell whether or not said mobile communication device is a member of said CSG; and generating and transmitting a message comprising, for each CSG, information identifying the CSG and information indicating the membership of said mobile communication device in said CSG.