GB2492584A

GB2492584A - Determining authorization to access neighbouring CSG cells or private cells, using PCI or PCI and CSG ID.

Info

Publication number: GB2492584A
Application number: GB201111627A
Authority: GB
Inventors: Tero Henttonen; Aschan Kennett
Original assignee: Renesas Mobile Corp
Current assignee: Renesas Electronics Corp
Priority date: 2011-07-07
Filing date: 2011-07-07
Publication date: 2013-01-09
Also published as: GB201111627D0

Abstract

A user equipment UE stores a first list of private cells to which the UE is authorized to access 202 (e.g. a closed subscriber group CSG whitelist). While under control of a serving first cell, the UE determines from a transmission received from a neighbour second cell a physical cell identity PCI of the neighbour cell, then compares the determined PCI to a stored second list to determine whether the UE is authorized to access the neighbour cell. In one embodiment the second list maps PCIs to CSG IDs 204; if the determined PCI matches one in the second list the CSG ID is selected and it that matches one in the first list the UE is authorized access. In another embodiment (figure 3) the second list is only the PCI of those CSG cells on the UE's first list that are within the area served by the serving cell (304), so if the determined PCI matches one in the second list the UE is authorized access.

Description

Improvements to Wireless Communication Systems and Methods

Technical Field

The present invention relates generally to wireless communication systems, methods, devices and computer programs, and more specifically relates to enabling a user equipment to determine whether or not the user equipment is authorized access to a neighbor/private cell.

Background

The following abbreviations used in the specification and/or the drawings are defined as follows: 3GPP third generation partnership project CSG closed subscriber group DL downlink (network towards UE) eNodeB base station ofaLTE/LTE-A system E-UTRAN evolved universal terrestrial radio access network ID identifier LTE long term evolution (of the E-UTRAN system) MAC medium access control MME mobility management entity PLMN public land mobile network S-OW serving gateway SCH shared channel RRC radio resource control IJE user equipment IJL uplink (UE towards network) In the E-IJTRAN system there are conventional network access nodes/cells termed eNodeBs which serve all users, and also subscriber group CSG cells such as home eNodeBs which are available for traffic (voice and/or data) to only those subscribers registered with the CSG and possibly also certain allowed guests. Any given CSG may include a group of cells (such as a corporate or university campus) or a single cell. CSGs may allow traffic access for non-subscribers for emergency calls but these teachings relate to routine, non-emergency access.

These different types of cells or access nodes may be termed more generally as public access nodes/public cells and private access nodes/private cells. Other wireless systems (GERAN, GSM, UTRAN, WCDMA) have either implemented or are considering implementing similar such private networks as more functionality is shifted from higher in the radio access network toward the base stations/access nodes.

In the LTE system the UE maintains a list, termed a CSG whitelist or CSG allowed list, which lists the identities of the CSG cells for which that particular UE has access rights. The wireless specifications at 3GPP TS 36.300 for LIE Release 9 stipulate that an E-UTRAN network may configure a UE to report that the TIE has detected that it has entered or left the proximity of a CSG cell to which the liE is allowed to connect. In the art these are termed proximity indications, and their purpose is to facilitate UE handovers from macro cells to CSG cells. Such handovers tend to improve the efficient use of network resources since after the handover that TiE's traffic is offloaded from the conventional cellular network macro cells to instead pass through the CSG cell(s).

More specifically, 3GPP TS 23.401 states that the UE is to keep this CSG whitclist, which can be either the "allowed CSG list" or the "operator CSG list" contained in the so-called IJE context which is provided by the TiE's home network to any other networks the UE is transiting. Each CSG list has the form of a list of CSG IDs and the associated PLMNs. Each CSG ID reliably identifies a CSG, which as above might include a single CSG cell or multiple CSG cells.

Figure 1 illustrates a relevant wireless environment; a TIE 20 is connected to a macro cell 22 and moving toward a CSG cell 24. While only one is shown, in practice there may be many CSG cells from different CSGs and the liE may be a subscriber to only one or a few of those CSGs. In order for the liE 20 to determine whether or not it has access rights to that CSG cell 24 it must acquire the CSG ID of that CSG in order to check it against the UE's own CSG whitelist.

The most accurate way to determine the CSG ID of a CSG cell 24 is for the liE 20 to read the system information of that cell 24. The liE 20 will read the CSG ID from the System Information Block Typel message which is part of the system information broadcast by the CSG cell 24 on the DL-SCH as set forth at 3GPP TS 36.331. However, reading system information of a neighbor (non-serving) cell means the TIE cannot at the same time remain in contact with the macro (serving) cell 22 to which it is connected (assuming as is typical that the IJE is using the same radio receiver to tune between the CSG cell's broadcast channel and the macro ccli's DL control channel over which resource allocations or pages arc sent). If there were only one CSG cell 24 as shown in Figure 1 the problem is minor, but where there are multiple CSG cells this can easily result in disrupting normal communications between the TIE 20 and its connected macro cell 22. The inventors consider that it is not desirable to require TiEs to read the system information of every neighbor cell whose broadcast channel they can hear, for this makes the TIE less available to its serving cell for regular data transmissions.

Summary

In a first exemplary embodiment of the invention there is provided an apparatus for use in controlling access by a user equipment to a cell in a communication network, the apparatus comprising a processing system, which, in one arrangement may be configured as at least one processor and at least one memory storing a computer program. In this embodiment the processing system is ananged to: store in the at least one memory a first list of private cells to which the apparatus is authorized to access; while under control of a serving first cell, determine from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; and compare the determined physical cell identity to a second list stored in the at least one memory to determine whether the apparatus is authorized to access the neighbor second cell.

In a second exemplary embodiment of the invention there is provided a method of controlling access by a user equipment to a cell in a communication network, the method comprising: storing in a memory accessible by the user equipment a first list of private cells to which the user equipment is authorized to access; while under control of a serving first cell, determining from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; and comparing the determined physical cell identity to a second list stored in the memory to determine whether the user equipment is authorized to access the neighbor second cell.

In a third exemplary embodiment of the invention there is provided a computer readable memory comprising a set of instructions, which, when executed by a user equipment, causes the user equipment to perform the steps of storing in a memory accessible by the user equipment a first list of private cells to which the user equipment is authorized to access; while under control of a serving first cell, determining from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; and comparing the determined physical cell identity to a second list stored in the memory to determine whether the user equipment is authorized to access the neighbor second cell.

These and other embodiments and aspects are detailed below with particularity.

Brief Description of the Drawings:

Figure 1 is a schematic diagram illustrating an environment in which embodiments of the invention may be practiced to advantage.

Figure 2 is a signaling diagram illustrating signaling and actions taken in accordance with a first exemplary embodiment of the invention.

Figure 3 is a signaling diagram illustrating signaling and actions taken in accordance with a second exemplary embodiment of the invention.

Figure 4 is a logic flow diagram that illustrates the operation of a method, and a result of execution of computer program instructions embodied on a computer readable memory, in accordance with the exemplary embodiments of this invention.

Figure 5 is a simplified block diagram of various network devices and a UE similar to those shown at Figure 1, which are exemplary electronic devices suitable for use in practicing the exemplary embodiments of the invention.

Detailed Description:

While past practice has often assumed that the UE 20 would read the system information block of the neighbor cells, in fact a close reading of the LTE specifications reveal that they do not stipulate a specific mechanism by which the UE 20 is to determine the CSG ID of its neighbor CSG cells 24. The liE 20 may be requested by its sewing cell 22 to read the system information of neighbor cell 24, but this is a deliberate procedure initiated by serving cell 22 and disrupts communication between UE 20 and the serving cell 22 for the duration of the system information reading. In principle the UE manufhcturers might choose to base their proximity indications on some less accurate information, such as the ID of the macro ccli 22 or the PCI of the CSG cell. In LTE the PCI is not unique per cell and so the CSG II) is a more reliable cell identifier (though the global cell II) (JCW formed by combining the PCI, CSG II) and the PLMN ID is the truly unique identifier for a CSG cell). There are only 504 possible PCIs, and so in a given PLMN such as any moderately-sized city with included suburbs there is likely to be more than 504 distinct access nodes and so some PCIs will be it-used within the same PLMN. In practice the re-used PUs are assigned to cells which are physically distant from one another but any optimization in this regard tends to diminish as cells are added and re-positioned over time. In LTE the cell uses its PCI to transmit data, whereas it uses the CSG ID (or other type of Cell ID for non-CSG cells) to identifr the cell since it is far more reliable in identil54ng a specific CSG cell than is the PCI. This is different than (ISM which uses the unique cell ID for both purposes. One non-limiting manner by which a liE can obtain the PCI of an Lit neighbor private cell is by reading it from the synchronization signal which the private cell broadcasts. This reading process is a normal measurement operation supported by all Lit UEs.

Neither the macro cell's unique CELL ID nor the CSG cell's PCI are sufficiently accurate for proximity indications and so they cannot reasonably be used for facilitating handovers and cell re-selections. This is because the inherent inaccuracies in the identifiers would likely result in dropped connections during attempted handovers from a macro cell to a CSG cell. Typical UE manufacturers tend to avoid such flaws that are so manifest to the users, and network operators generally will not take proximity indications into usc if their inaccuracy routinely results in handover-related dropped connections.

The solution is for the UE to obtain the CSG ID but without having to decode system infbrmation from all the neighbor cells it sees. Such a solution is detailed below in the context of an Lit system, recognizing this is but one example and the broader teachings herein can be employed also with other types of radio access technologies.

RcfcrringagaintoFigurcl,considerthemacroceil22asafirstcellwhichis theservingcellfortheuE2O,andtheCSGcell24asasecondcellwhichisa neighbor cell which the UR will determine according to these teachings is or is not a CSG cell to which the TJE 20 is authorized to access (e.g., whether the TJE 20 is a subscriber or authorized guest for that CSG cell 24). There is a first list stored in the UE's local memory which is the IJE's CSG whitelist mentioned above, which lists the CSG IDs of the CSG cells which the UE 20 is authorized to access. There is also a second list stored in the IJE's local memory which may take different forms according to the first and second embodiments below. At minimum the second list has the physical cell IDs. While a more generic term for CSG ID is simply cell ID, the term physical cell identity is itself generic since a few different radio access technologies employ physical iDs for cells as well as various forms of a cell identifier. As used herein, cell identifier and physical cell identity refer to different types of IDs, with cell identifier representing the more reliable of the two for uniquely identifying a given cell. In some embodiments the cell identifier may be truly unique and in others, such as the CSG ID in the LTE system it is not quite unique but a better choice for reliably In accordance with an exemplary embodiment, the liE 20 stores in its local memory that first list, which is the private cells to which the liE 20 is authorized to access. While under control of the serving first cell 22 (e.g., in a connected state or idle state or various other states in different radio technologies), the UE 20 then determines from a transmission by the neighbor second cell 24 a physical cell identity of the neighbor second cell 24. By example such a transmission may be a synchronization signal which the neighbor second cell 24 broadcasts on its primary broadcast channel; it is far less power intensive and time consuming for the liE 20 to receive and decode the synchronization signal than it is to receive and decode an entire system information block.

The tiE 20 then compares the determined physical cell identity to the second list which is also stored in its local memory, to determine whether the liE 20 is authorized to access the neighbor second cell. In a first embodiment detailed below this second list is a mapping of PCIs to CSG-lDs, and so once the TiE 20 matches the PCI obtained from the synchronization signal it can know from the second list the CSG-ID of the neighbor second cell 24. Then by checking this CSG-ID against the first list (CSG whitelist) which has the allowed CSG IDs the liE 20 can assume whether or not it is authorized to access that neighbor second cell 24. In the second embodiment detailed below the second list is a list of PCIs, tailored for the liE 20 by the network, and which contains the PCIs of only those CSG cells which are on the liE's first list and which are also in the coverage area of the UE's serving first cell 22.

In this second embodiment, matching the PCI obtained from the synchronization signal to a PCI in the second list is sufficient for the UE 20 to assume it can access that neighbor second cell 24. Common to both embodiments, the TilE 20 obtains the PCI information of its member CSG cells from the macro eNodeB 22 based on the UE's CSG whitelist.

The first embodiment is detailed further with respect to the signahng diagram of Figure 2. The liE 20 has stored in its local memory at block 202 the conventional CSG whitelist or the first list. The liE 20 is provisioned with this list from its home network, from the serving 1st cell 22, or from an update from the home network passed through its current serving cell 22 or some previous serving cell (not shown).

There is a second list which the serving first cell 22 transmits to the UE 20, and this second list has a mapping of CSG IDs to PCIs so that each CSG ID is associated in the second list with one and only one PCI.

By example the serving cell 22 can send this second list to the UE 20 in response to a specific request by the UE at uplink message 203a. Such a request may be via an RRC message, a MAC message, or a layer I Li control message for example. Alternatively the serving cell 22 may send it to the liE 20 automatically in response to the UE becoming connected to thc serving first cell 22 such as in response to the liE's RRC-CONNECTION COMPLETE message at 203b. In another alternative, since in this embodiment the CSG-ID to PCI map/second list is not specific to the particular UE 20 but rather maps the CSG IDs for all CSG cells in the macro cell's coverage area to their respective PCls, the macro cell 24 may simply transmit (e.g. broadcast or unicast) the second list at message 204 to all UEs in its coverage area. However it receives the list, the TiE 20 also stores this second list in its local memory at block 206.

The liE 20 subsequently detects a neighbor cell 24. Rather than read and decode its entire system information block the TilE 20 instead reads just a smaller transmission by that neighbor second cell 24, such as for example its synchronization signal 208 on the broadcast channel. From that transmission 208 the TiE can read the PCI of the transmitting cell 24, which the UE 20 stores in its memory at 210. The liE then uses the PCI obtained and stored at block 210 to see if there is a match to any

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PCI in the second list which was stored at block 206. If there is a match, the UE 20 obtains the CSG-ID for the neighbor second cell 24 by identifying the one CSG ID that is associatcd in that second list with the matched PCI, and then checks so see if that CSG ID is on the first list. If yes the TJE 20 assumes it has access rights to that neighbor second cell 24, and if not then the UE 20 assumes it does not.

In the event that the TJE 20 has access rights to the neighbor second cell, for example if the TIE 20 is in a RRC CONNECTED state with the serving first cell, the TIE 20 may send a proximity indication to the macro cell 22 (214a), and the macro cell will determine if and when a handover to the neighbor second cell 24 is appropriate and initiate such a handover (214b). If instead the TIE 20 is in a RRC-IDLE state with the macro cell 22, the liE 20 can initiate via message 214c a handover to the neighbor second cell 24 itself at an appropriate time. Specific handover procedures then follow conventional practice.

The second embodiment is now detailed with reference to the signaling diagram of Figure 3. Like the first embodiment, the liE 20 has stored in its local memory at block 302 the conventional CSG whitelist!first list which it obtains as noted above for Figure 2. In this second embodiment the second list is tailored to the specific TIE 20, and so at block 302b the serving first cell 22 obtains the UE's CSG whitelist. While it is possible for the serving first cell 22 to obtain this CSG whitelist from the liE 20 itself, to avoid additional wireless signaling overhead Figure 3 illustrates that the serving first cell 22 obtains it from the UE's home network, such as when the sewing first cell 22 obtains the liE's context via higher network nodes (not shown). The serving first cell 22 then creates the second list which is a list of PCIs for all the CSG cells which are both within the liE's CSG whitelist and also within the serving first cell's coverage area. It follows then that if the liE 20 can match a PCI to this second list, the UE 20 assumes it must have access rights to the cell which transmitted that PCI. The serving first cell 22 transmits this second list to the TIE 20 at message 304.

Similar to the steps described above with reference to Figure 2, the sewing cell 22 can send this second list to the liE 20 in response to a specific request by the TIE at uplink message 303a (e.g., an RRC message, a MAC message, or a layer 1 LI control message). Alternatively the serving cell 22 may send it to the liE 20 automatically in response to the TIE becoming connected to the serving first cell 22 such as in response to the UE's RRC-CONNECTION COMPLETE message at 303b.

Unlike the first embodiment, since the second list of PCIs is tailored to the particular UE 20 it is not efficient for the serving first cell 22 to broadcast the second list.

However the UE 20 receives it, it also stores this second list in its local memory at block 306.

As for the first embodiment, the TilE 20 at Figure 3 then detects a neighbor cell 24 and reads the neighbor second cell's synchronization signal 308 on the broadcast channel or other smaller transmission. From that transmission 308 the UE reads the PCI of the transmitting cell 24, and this PCI the tiE 20 also stores in its memory at 310. The TilE 20 then uses the PCI obtained and stored at block 310 to see if there is a match to any PCI in the second list which was stored at block 306. If yes the tiE 20 assumes it has access rights to that the neighbor second cell 24, and if no the TiE 20 assumes it does not.

In the event that the TiE 20 has access rights to the neighbor second cell, for example if the tiE 20 is in a RRC CONNECTED state with the serving first cell, the tiE 20 may send at message 314a a proximity indication to the macro cell 22, and the macro cell will determine if and when a handover to the neighbor second cell 24 is appropriate and initiate such a handover using message 3 14b. In this case, the TiE 20 can report the proximity information and identify the neighbor second cell by its PCI, for which the serving first cell 22 will know the matching CSG ID. While the serving cell can order the RRC-CONNECTED liE 20 to read the system information of its neighbor cell 24 prior to a handover thereto, typically the tiE 20 will only read that system information after the handover so as not to disrupt communications with the serving cell 22. Where the neighbor cell 24 is a CSG cell it might be helpful in conventional practice that the tiE 20 reads that neighbor's system information prior to the handover to obtain the CSG ID and thereby avoid re-selecting to a neighbor CSG cell for which the TiE 20 has no access rights. However, in practice this may not be required, since the exemplary embodiments of these teachings allow the TiE 20 in the RRC-CONNECTED state to assume with a high degree of accuracy the CSG ID of that neighbor cell without having to read its system information.

If instead the TiE 20 is in a RRC-IDLE state with the macro cell 22, the TiE 20 can initiate via message 3 l4c a handover to the neighbor second cell 24 itself at an appropriate time. In this latter case the TilE 20 can read the entire system information block of the neighbor second cell 24 if it deems handover to it appropriate, but note this still avoids the liE 20 having to read and decode system information for all its neighbor cells including those CSG cells for which it has no access rights; the TIE's decoding burden for neighbor cell system information will be restricted to only a few for which the liE 20 has access rights. Specific handover procedures then follow conventional practice.

In the LTE system there is a mobility management entity MME, which often also functions as the serving gateway S-GW, which is a control/management node higher in the network than the eNodeBs. Embodiments of the invention as detailed above may be facilitated by the following processes higher in the macro network. For each macro cell, the MME will maintain a list of all the CSG cells in the coverage area of the macro cell. This list has an entry for each CSG cell, and each entry in the list is a set of numbers including the canier frequency, the PCI and the CSG ID. To implcmcnt this aspect there will need to be new signaling arranged between the MME and the macro cell 22 so that the macro cell 22 can obtain from the MME the appropriate CSG list for all the affected DEs in the macro cell's service area. As noted above the macro cell 22 can in different embodiments broadcast the list to all UEs or transmits the list to every TIE 20 that connects to the macro cell 22.

It is conventional that the UE 20 will at regular intervals search for the cells listed in the aforementioned list of CSG cells, in addition to performing normal neighbor cell measurements. Embodiments of these teachings may be initiated in conjunction with such searches; when the UE detects a CSG cell nearby during its routine search it reads the PCI of the neighbor second cell 24 from the synchronization signal which that cell 24 broadcasts. If the UE 20 then finds the PCI in the second list which has the PCI numbers, then as detailed above for the first and second embodiments the UE 20 is able to determine the corresponding CSG ID -either from the second list if the first embodiment or from decoding system information if the second embodiment. For the first embodiment, if the liE 20 finds the CSG ID in its first list (the CSG whitelist which has the CSG numbers), then the liE 20 is able to infer that it is allowed to connect to the CSG cell 24. For the second embodiment if the UE 20 finds the PCI it read from the neighbor second cell's transmission in its second list (the PCI list tailored to the particular UE 20), then the TIE 20 is able to infer that it is allowed to connect to the CSG cell 24 because the network created the second list such that it includes only PCIs for CSG cells in that specific UE's CSG whitelist.

Embodiments of the invention as described by example above, and particularly the manner by which the tJE 20 can obtain the CSG ID of a neighbor second cell 24 without having to read and decode system information from all its neighbor cells, provide the technical effect of improving accuracy for the UE's proximity indication. Since the UE only indicates proximity when the cell is measurable, the UE's proximity indications received by the eNodeB are much more accurate than competing approaches detailed in the background section above. For example, the measurement value of the eNodeB can be provided in the proximity report. Mother technical effect is that embodiments of these teachings enable the UE to detect whether it is in the proximity of CSG cells 24 that it is allowed to connect to without reading the system information of all those neighbor cells 24.

The above teachings can be readily expanded beyond only CSG cells. For example, implementations in which the network sends to the tiE 20 the second list upon the UE 20 becoming established in the macro cell 22 can be adapted so that there are additional types of cells, apart from or in addition to CSG cel1s including within that network-provided list. The tJE 20 can for example send to the macro cell 24 a proximity indication for a WLAN cell or other type of special' cell which under certain conditions (for example, a static Ut or limited UE mobility for the case of WLAN) the macro cell 22 may choose to offload some of the UE's traffic to that special cell. Such indication could also contain additional information regarding the WLAN cell similar to measurement information that can be provided for an LTE cell.

Note that in the above embodiments there is still a possibility that the UE 20 can confuse different CSG cells which use the same PCI, but this lack of absolute certainty is not seen as an impediment since in practice such cell confusion is a remote possibility given that when the network is built and evolving the same PCI is assigned only to cells that are distant from one another.

Figure 4 above is a logic flow diagram which describes the above exemplary embodiments of the invention fixm the perspective of the UE 20. Figure 4 represents results fixm executing a computer program or an implementing algorithm stored in the local memory of the UE 20, as well as illustrating the operation of a method and a specific manner in which the processor and memory with computer programialgorithm are configured to cause that TJE 20 (or one or more components thereof) to operate. The various blocks shown in Figure 4 may also be considered as a plurality of coupled logic circuit elements constructed to carry out the associated function(s), or specific result or function of strings of computer program code stored in a computer readable memory.

Such blocks and the functions they represent are non-limiting examples, and may be practiced in various components such as integrated circuit chips and modules, and that the exemplary embodiments of this invention may be realized in an apparatus that is embodied as an integrated circuit. The integrated circuit, or circuits, may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or data processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this invention.

Blocks 402 and 404 and 406 arc generic to the first and second embodiments, and further process blocks of Figure 4 are optional for various different embodiments and implementations. At block 402 the apparatus stores in its local memory a first list of private cells to which the apparatus is authorized to access. At block 404, while under control of a serving first cell, the apparatus determines from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell. And at block 406 then is compared the determined physical cell identity to a second list stored in the memory to determine whether the apparatus is authorized to access the neighbor second cell.

The first embodiment detailed also at Figure 2 is summarized at block 408: the first list is detailed as comprising a cell identifier (e.g., CSG ID) for each of the private cells to which the apparatus is authorized to access; the second list comprises a one-to-one mapping of physical cell identities to cell identifiers for at least some of the private cells to which the apparatus is authorized to access (the CSG ID to PCI mapping); the determination at block 406 involves checking the second list for a physical cell identity which matches the determined physical cell identity; if there is a match, the cell identifier which maps to the matched physical cell identity is selected, and it is concluded that the apparatus is authorized to access the neighbor second cell if the cell identifier selected from the second list matches a cell identifier within the first list. As noted above with respect to Figure 2 in one implementation the second list is received from the serving first cell on a broadcast channel. The cell identifiers arc diffcrcnt in type from the physical cell identities; that is any given ccli (the neighbor sccond cdl) may be assigned onc of each.

The second embodimcnt detailed also at Figure 3 is summarized at block 410: the first list is detailed as comprising a cell identifier (e.g., CSG ID), different from the physical cell identity, for each of the private cells to which the apparatus is authorized to access; the second list comprises a list of physical cell identities for at least some of the private cells to which the apparatus is authorized to access (e.g., the UE-specific PCI listing for only the CSGs within the liE's CSG whitelist which are also located in the area of the serving cell); the determination at block 406 involves checking the second list for a physical cell identity which matches the determined physical cell identity; if a match is found it is concluded that the apparatus is authorized to access the neighbor second cell. In this embodiment also the cell identifiers are different in type from the physical cell identities.

Blocks 412 and 414 and 416 are each generic to either embodiment of blocks 408 and 410. At block 412 the second list is wirelessly received from the serving first cell when the TJE first establishes a radio connection with the serving fir st cell. Such a radio connection may in an LTE system be a RRC-CONNECTED state. At block 414 the second list is wirelessly received from the serving first cell in response to a request by the UE 20 for the second list. And at block 416, in response to determining at block 406 there is the ifirther process step of either or both of sending to the serving first cell a proximity indication for the neighbor second cell; and!or initiating a handover to the neighbor second cell.

As described above, Figure 4 represents the case in which the UE is in the RRC-CONNECTED state (assuming an LTE implementation). For the case in which the liE is in the RRC-IDLE state for an LTE implementation, such a liE would be camped under the serving cell instead of under control thereof that being the case, it would initiate a handover to the neighbor second cell based on the priority indication status at block 416, and block 414 would not apply. In various embodiments the apparatus executing the process described at Figure 4 may be the liE 20 as described, or one or more components thereof such as for example a wireless modern configured for use in a UE 20.

Reference is now made to Figure 5 for illustrating a simplified block diagram of various electronic devices and apparatus that are suitable for use in practicing the exemplary embodiments of this invention. In Figure 5 a serving first cell/macro cell 22 is adapted for communication over a wireless link with a mobile apparatus, such as a mobile terminal or lIE 20. The macro cell 22 may be a macro cNodcB, a remote radio head or relay station, or other type of base station/cellular network access node.

The UE 20 includes processing means such as at least one data processor (DF) 20A, storing means such as at least one computer-readable memory (MEM) 20B storing at least one computer program (PROG) 20C, and also communicating means such as a transmitter TX 20D and a receiver RX 20E for bidirectional wireless communications with the serving fir st cell/macro cell 22 via one or more antennas 20F. Also shown for the IJE 20 at block 200 is the first list implemented as the CSG whitelist and the second list implemented as either the PCI to CSG ID mapping or the PCI list which is specific to that UE 20.

The serving first cellimacro cell 22 similarly includes processing means such as at least one data processor (DP) 22A, storing means such as at least one computer-readable memory (MEM) 22B storing at least one computer program (FROG) 22C, and communicating means such as a transmitter TX 22D and a receiver RX 22E for bidirectional wireless communications with the UE 20 via one or more antennas 22F.

There is a data and/or control path, termed at Figure 5 as a control link which in the LTE system may be implemented as an SI interface, coupling the serving first cell/macro cell 22 with the S-GW/MME 28 and over which the serving first cell/macro cell 22 may receive the liE's CSG whitelist in various embodiments above. The serving first cell/macro cell 22 creates and stores at block 22G the PCI to CSG ID mapping or the liE specific PCI lists of the various embodiments as detailed above.

Similarly, the S-GW/MME 28 includes processing means such as at least one data processor (DP) 28A, storing means such as at least one computer-readable memory (MEM) 28B storing at least one computer program (PROG) 28C, and communicating means such as a modem 28H for bidirectional communication with the serving first cell/macro cell 22 via the control link and also with the neighbor second cell 24 over the other control link. While not particularly illustrated for the UE 20 or serving first cell/macro cell 22 or neighbor second cell 24, those devices are also assumed to include as part of their wireless communicating means a modem which may be inbuilt on a radiofrequency RF front end chip within those devices 20, 22, 24 and which chip also carries the TX 20D/22D/24D and the RX 20E/22E/24E.

The S-GW/MME 28 also has stored in its local memory at 280 the database which has the CSG-PCI mapping for all the eNodeBs under its control, and br the CSG whitelists for all the liEs under those various eNodeBs as the case may be for the various embodiments detailed above.

The neighbor second cell 24 includes its own processing means such as at least one data processor (DP) 24A, storing means such as at least one computer-readable memory (MEM) 24B storing at least one computer program (PROG) 24C, and communicating means such as a transmitter TX 24D and a receiver RX 24E for bidirectional wireless communications with other liEs under its control via one or more antennas 24F. In certain implementations the neighbor second cell 24 may be embodied as a home eNodeB, referred to in LTE sometimes as a HeNB.

At least one of the PROGs 20C in the UE 20 is assumed to include program instructions that, when executed by the associated DP 20A, enable the device to operate in accordance with the exemplary embodiments of this invention, as detailed above. The serving first cell 22 and the S-GW/MME 28 also have software stored in their respective MEMs to implement certain aspects of these teachings. In these regards the exemplary embodiments of this invention may be implemented at least in part by computer software stored on the MEM 20B, 22B, 28B which is executable by the DP 20A of the UE 20 and/or by the DP 224'28A of the respective serving first cell 22 and the S-GW/MME 28, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware). Electronic devices implementing these aspects of the invention need not be the entire devices as depicted at Figure 5, but exemplary embodiments may be implemented by one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, or a system on a chip SOC or an application specific integrated circuit ASIC.

Various embodiments of the computer readable MEMs 20B, 22B, 24B and 28B include any data storage technology type which is suitable to the local technical environment, including but not limited to semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and the like. Various embodiments of the DPs 20A, 22A, 24A and 28A include but are not limited to general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors.

Further, some of the various fcatures of the above non-limiting cmbodiments may be used to advantage without the corresponding use of other described features.

The foregoing description should therefore be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof

Claims

<claim-text>Claims: 1. An apparatus for use in controlling acccss by a user equipment to a ccli in a communication network, thc apparatus comprising a processing systcm arranged to: store in the at least one memory a first list of private cells to which the apparatus is authorized to access; while under control of a serving first cell, determine from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; and compare the determined physical cell identity to a second list stored in the at least one memory to determine whether the apparatus is authorized to access the neighbor second cell.</claim-text> <claim-text>2. Thc apparatus according to claim 1, wherein the first list comprises a cell identifier for each of the private cells to which the apparatus is authorized to access, the second list comprises a one-to-one mapping of physical cell identities to cell identifiers!br at least some of the private cells to which the apparatus is authorized to access, and the processing system is arranged to: check the second list for a physical cell identity which matches the determined physical cell identity; select from the second list the cell identifier which maps to the matched physical cell identity; and determine that the apparatus is authorized to access the neighbor second cell if the cell identifier selected from the second list matches a cell identifier within the first list.</claim-text> <claim-text>3. Thc apparatus according to claim 2, wherein the proccssing system is arranged to receive the second list from the serving first cell on a broadcast channel.</claim-text> <claim-text>4. The apparatus according to claim I or claim 2, wherein the processing system is arranged to receive the second list from the serving first cell when the user equipment first establishes a radio connection with the serving first cell.</claim-text> <claim-text>5. The apparatus according to claim 1 or claim 2, wherein the processing system is arranged to receive the second list from the serving first cell in response to a request by the user equipmcnt for the second list.</claim-text> <claim-text>6. The apparatus according to claim 1, wherein the first list comprises a cell identifier for each of the private cells to which the apparatus is authorized to access, the second list comprises a list of physical ccli identities for at least some of the private cells to which the apparatus is authorized to access, and the processing system is arranged to check the second list for a physical cell identity which matches the determined physical cell identity and if a match is found, determine that the apparatus is authorized to access the neighbor second cell.</claim-text> <claim-text>7. The apparatus according to claim 6, wherein the processing system is arranged to receive the second list from the serving first cell, the second list comprising the physical cell identities of only those cells which are within the first list and within a service area of the serving first cell.</claim-text> <claim-text>8. The apparatus according to claim 6 or claim 7, wherein the processing system is arranged to receive the second list from the serving first cell when the user equipment first establishes a radio connection with the serving first cell.</claim-text> <claim-text>9. The apparatus according to claim 6 or claim 7, wherein the processing system is arranged to receive the second list from the serving first cell in response to a request by the user equipment for the second list.</claim-text> <claim-text>10. The apparatus according to any one of the prcceding claims, wherein said transmission received from the neighbor second cell comprises a synchronization signal, and the processing system is arranged to decode the synchronization signal whereby to determine said physical cell identity of the neighbor second cell.</claim-text> <claim-text>11. The apparatus according to any one of the preceding claims, wherein, in response to determining whether the apparatus is authorized to access the neighbor second cell, the processing system is further arranged to: send to the serving first cell a proximity indication for the neighbor second cell; or initiatc a handover to the neighbor second cell.</claim-text> <claim-text>12. The apparatus according to any one of the preceding claims, wherein the apparatus comprises a modem.</claim-text> <claim-text>13. A method of controlling access by a user equipment to a cell in a communication network, the method comprising: storing in a memory accessible by the user equipment a first list of private cells to which the user equipment is authorized to access; while under control of a serving first cell, determining from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; and comparing the determined physical cell identity to a second list stored in the memory to determine whether the user equ[pment is authorized to access the neighbor second cell.</claim-text> <claim-text>14. The method according to claim 13, in which: the first list comprises a cell identifier for each of the private cells to which the user equipment is authorized to access; the second list comprises a one-to-one mapping of physical cell identities to cell identifiers for at least some of the private cells to which the user equipment is authorized to access; and said determination as to whether the user equipment is authorized to access the neighbor second cell comprises: checking the second list for a physical cell identity which matches the determined physical cell identity; selecting from the second list the cell identifier which maps to the matched physical cell identity; and determining that the user equipment is authorized to access the neighbor second cell if the cell identifier selected from the second list matches a cell identifier within the first list.</claim-text> <claim-text>15. The method according to claim 13, in which: the first list comprises a cell identifier for each of the private cells to which thc user equipment is authorized to access; the second list is wirelessly received from the serving first cell, and comprises the physical cell identities of only those cells which are within the first list and within a service area of the serving first cell; and said determination as to whether the user equipment is authorized to access the neighbor second cell comprises checking the second list fbr a physical cell identity which matches the determined physical cell identity and if a match is found determining that the user equipment is authorized to access the neighbor second cell.</claim-text> <claim-text>16. The method according to any one of claim 13 to claim 15, in which the second list is wirelessly received from the serving first cell when the user cquipment first establishes a radio connection with the serving first cell.</claim-text> <claim-text>17. The method according to any one of claim 13 to claim 15, in which the second list is wirelessly received flx,m the serving first cell in response to a request by the user equipment for the second list.</claim-text> <claim-text>18. The method according to any one of claim 13 to claim 15, in which, in response to determining whether the user equipment is authorized to access the neighbor second cell, the method further comprises: sending to the serving first cell a proximity indication for the neighbor second cell; or initiating a handover to the neighbor second cell.</claim-text> <claim-text>19. A computer readable memory comprising a set of instructions, which, when executed by a user equipment, causes the user equipment to perform the steps of storing in a memoty accessible by the user equipment a first list of private cells to which the user equipment is authorized to access; while under control of a serving first cell, determining from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; and comparing the determined physical ccli identity to a second list stored in the memory to dctcrminc whether the user equipment is authorized to access the neighbor second cell.</claim-text> <claim-text>20. A computer readable memory according to claim 19, in which the first list comprises a cell identifier for each of the private cells to which the user equipment is authorized to access, the second list comprises a one-to-one mapping of physical cell identities to cell identifiers for at least some of the private cells to which the user equipment is authorized to access; and said set of instructions flirther causes the user equipment to perform the steps of checking the second list for a physical cell identity which matches the detcrmined physical cell identity; selecting flm the second list the cell identifier which maps to the matched physical cell identity and determining that the user equipment is authorized to access the neighbor second cell if the cell identifier selected from the second list matches a cell identifier within the first list, whereby to execute said determination as to whether the user equipment is authorized to access the neighbor second cell.</claim-text> <claim-text>21. A computer readable medium according to claim 19, in which the first list comprises a ccli identifier for each of the private cells to which the user equipment is authorized to access, the second list is wirelessly received from the serving first cell and comprises the physical cell identities of only those cells which are within the first list and within a service area of the serving first cell; and said set of instructions further causes the user equipment to perform the step of checking the second list for a physical cell identity which matches the determined physical cell identity and if a match is found determining that the user equipment is authorized to access the neighbor second cell, whereby to execute said determination as to whether the user equipment is authorized to access the neighbor second cell.Amendments to the Claims have been filed as follows Claims: I. An apparatus for use in controlling access by a user equipment to a cell in a communication network, the apparatus comprising a processing system arranged to: store in the at least one memory a first list of private cells to which the apparatus is authorized to access; while under control of a serving first cell, determine from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; compare the determined physical cell identity to a second list stored in the at least one memory to determine whether the apparatus is authorized to access the neighbor second cell; and in response to determining whether the apparatus is authorized to access the neighbor second cell, send to the serving first cell a proximity indication for the (\J 15 neighbor second cell, wherein the proximity indication includes a measurement value of the neighbor second cell.
2. The apparatus according to claim 1, wherein the first list comprises a cell C') identifier for each of the private cells to which the apparatus is authorized to access, the second list comprises a one-to-one mapping of physical cell identities to cell identifiers for at least some of the private cells to which the apparatus is authorized to access, and the processing system is arranged to: check the second list for a physical cell identity which matches the determined physical cell identity; select from the second list the cell identifier which maps to the matched physical cell identity; and determine that the apparatus is authorized to access the neighbor second cell if the cell identifier selected from the second list matches a cell identifier within the first list.
3. The apparatus according to claim 2, wherein the processing system is arranged to receive the second list from the serving first cell on a broadcast channel.
4. The apparatus according to claim or claim 2, wherein the processing system is arranged to receive the second list from the serving first cell when the user equipment first establishes a radio connection with the sewing first cell.
5. The apparatus according to claim 1 or claim 2, wherein the processing system is arranged to receive the second list from the serving first cell in response to a request by the user equipment for the second list.
6. The apparatus aecordiag to claim I, wherein the first list comprises a cell identifier for each of the private cells to which the apparatus is authorized to access, the second list comprises a list of physical cell identities for at least some of the private cells to which the apparatus is authorized to access, and the processing system is arranged to check the second list for a physical cell identity which matches the determined physical cell identity and if a match is found, determine that the apparatus (%J 15 is authorized to access the neighbor second cell.0
7. The apparatus according to claim 6, wherein the processing system is arranged to receive the second list from the serving first cell, the second list comprising the C1) physical eel] identities of only those cells which are within the first list and within a service area of the serving first cell.
8. The apparatus according to claim 6 or claim 7, wherein the processing system is arranged to receive the second list from the serving first cell when the user equipment first establishes a radio connection with the serving first cell.
9. The apparatus according to claim 6 or claim 7, wherein the processing system is arranged to receive the second list from the serving first cell in response to a request by the user equipment for the second list.
10. The apparatus according to any one of the preceding claims, wherein said transmission received from the neighbor second cell comprises a synchronization signal, and the processing system is arranged to decode the synchronization signal whereby to determine said physical cell identity of the neighbor second cell.
II. Thc apparatus according to any one of the preceding claims, wherein the apparatus comprises a modem.
12. A method of controlling access by a user equipment to a cell in a communication network, the method comprising: storing in a memory accessible by the user equipment a first list of private cells to which the user equipment is authorized to access; while tinder control of a serving first cell, determining from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; comparing the determined physical cell identity to a second list stored in the memory to determine whether the user equipment is authorized to access the neighbor (%J 15 second cell; and in response to determining whether the user equipment is authorized to access 0 the neighbor second cell, sending to the serving first cell a proximity indication for the neighbor second cell, wherein the proximity indication includes a measurement 0') value of the neighbor second cell.
13. The method according to claim 12, in which: the first list comprises a cell identifier for each of the private cells to which the user equipment is authorized to access; the second list comprises a one-to-one mapping of physical cell identities to cell identifiers for at least some of the private cells to which the user equipment is authorized to access; and said determination as to whether the user equipment is authorized to access the neighbor second ccli comprises: checking the second list for a physical cell identity which matches the determined physical cell identity; selecting from the second list the cell identifier which maps to the matched physical cell identity; and determining that the user equipment is authorized to access the neighbor second cell if the cell identifier selected from the second list matches a cell identifier within the first list.
14. The method according to claim 12, in which: the first list comprises a cell identifier for each of the private cells to which the user equipment is authorized to access; the second list is wirelessly received from the serving first cell, and comprises the physical cell identities of only those cells which are within the first list and within a service area of the serving first cell; and said determination as to whether the user equipment is authorized to access the neighbor second cell comprises checking the second list for a physical cell identity which matches the determined physical cell identity and if a match is found determining that the uscr equipment is authorized to access the neighbor second cell.("s.J 15
15. The method according to any one of claim 12 to claim 14, in which the second list is wirelessly rcccivcd from the serving first cdl when the user cquipmcnt first 0 establishes a radio connection with the serving first ccli.C1)
16. The method according to any one of claim 12 to claim 14, in which the second list is wirelessly received from the serving first cell in response to a request by the user equipment for the second list.
17. A computer readable memory comprising a set of instructions, which, when executed by a user equipment, causes the user equipment to perform the steps of: storing in a memory accessible by the user equipment a first list of private cells to which the user equipment is authorized to access; while under control of a serving first cell, determining from a transmission received from a neighbor second cell a physical cell identity of the neighbor second cell; comparing the determined physical cell identity to a second list stored in the memory to determine whether the user equipment is authorized to access the neighbor second cell; and in response to determining whether the user equipment is authorized to access the neighbor second cell, sending to the serving first cell a proximity indication for the neighbor second cell, wherein the proximity indication includes a measurement value of the neighbor second cell.
18. A computer readable memory according to claim 17, in which the first list comprises a cell identifier for each of the private cells to which the user equipment is authorized to access, the second list comprises a one-to-one mapping of physical eeH identities to cell identifiers for at least some of the private cells to which the user equipment is authorized to access; and said set of instructions further causes the user equipment to perform the steps of: checking the second list for a physical cell identity which matches the determined physical cell identity; selecting from the second list the cell identifier which maps to the (\J 15 matched physical cell identity; and determining that the user equipment is authorized to access the 0 neighbor second cell if the cell identifier selected from the second list matches a cell identifier within the first list, C') whereby to execute said determination as to whether the user equipment is authorized to access the neighbor second cell.
19. A computer readable medium according to claim 17, in which the first list comprises a cell identifier for each of the private cells to which the user equipment is authonzed to access, the second list is wirelessly received from the serving first cell and comprises the physical cell identities of only those cells which are within the first list and within a service area of the serving first cell; and said set of instructions frirther causes the user equipment to perform the step of checking the second list for a physical cell identity which matches the determined physical cell identity and if a match is found determining that the user equipment is authorized to access the neighbor second cell, whereby to execute said determination as to whether the user equipment is authorized to access the neighbor second cell.</claim-text>