WO2009001269A2

WO2009001269A2 - Apparatus, method and computer program product providing signaling between mobile terminal and network in presence of private cells/closed subscriber groups

Info

Publication number: WO2009001269A2
Application number: PCT/IB2008/052457
Authority: WO
Inventors: Jarkko T. Koskela; Lars Dalsgaard
Original assignee: Nokia Corporation; Nokia, Inc.
Priority date: 2007-06-22
Filing date: 2008-06-20
Publication date: 2008-12-31
Also published as: WO2009001269A4; WO2009001269A3

Abstract

A user equipment UE receives an indication that another cell apart from a serving network cell is a private network cell, determines that it is restricted from accessing the another cell, and excludes measurements of the another cell from uplink measurement reports that it sends to the serving network cell. The indication may be received in dedicated downlink signaling (handover command after a triggered measurement report), or broadcast from the serving cell or the private cell and the UE sees the private cell is not on its private cell whitelist. Depending on who sent the indication, the UE may signal the serving or a next eNB that it is restricted access to that private cell. The indication may be that an entire frequency layer is restricted access. The UE carries over its neighbor list from the most recent cell on which it was camped when transiting the restricted private cell.

Description

APPARATUS, METHOD AND COMPUTER PROGRAM PRODUCT PROVIDING

SIGNALING BETWEEN MOBILE TERMINAL AND NETWORK IN PRESENCE OF

PRIVATE CELLS/CLOSED SUBSCRIBER GROUPS

TECHNICAL FIELD:

[oooi] The exemplary and non-limiting embodiments of this invention relate generally to wireless communication systems, methods, devices and computer program products and, more specifically, relate to signaling between a mobile terminal and a wireless network where a private cell is present. The specific signaling is relevant to neighbor lists and access restrictions and configuring neighbor lists.

BACKGROUND:

[0002] Adjacent cell measurements are carried out in cell-based telecommunications systems for example as shown in Figures 1 and 2. As known to those skilled in the art, the adjacent cell measurements are the basis for handover and cell reselection decisions. The user equipment UE, also termed a mobile terminal MT, measures signal quality (such as signal strength, bit error rate BER, bit error probability BEP, or other signal quality parameters in use) from its serving cell and also from adjacent cells and reports these to the network in a measurement report. The measurement reports may be sent at regular intervals or in reply to a request/command from the network. The UE typically determines which cells are adjacent, and more narrowly which ones to measure, based on neighbor lists which in the prior art are delivered to the UEs on one or more control channels of the wireless system. The neighbor lists contain the necessary data about the adjacent cell so that the UE can find the neighbor cells easily and efficiently. Without the neighbor lists, the search for neighbor cells would consume excessive time and battery power of the UE.

[0003] In a large network with an extensive number of small cells, the process of determining the right or most appropriate neighbor to include in the neighbor lists that are used to configure the network is a substantial task. E-UTRAN (evolved universal mobile telecommunications system terrestrial radio access network, also known as 3.9G or long term evolution LTE) is developing to include more network cells than previous systems, including private networks (a single cell or group of cells) which E-UTRAN terms a closed subscriber group CSG network cell with home eNBs (evolved node B's, or more generally base stations or access nodes). Other wireless systems (GSM EDGE radio access network GERAN, global system for mobile communications GSM, UMTS terrestrial radio access network UTRAN, wideband code division multiple access WCDMA, orthogonal frequency division multiplexing OFDM) are also proceeding in this general direction incrementally as more functionality is shifted from the radio network controller RNC to the base stations BSs.

[0004] The presence of more densely packed eNBs/BSs, especially where some UEs do not have access rights, greatly increases signaling overhead in the area of maintaining the neighbor lists and the measurement reports underlying those lists. One currently proposed solution for configuring the network requires that the mobile terminals do the job of determining the neighbors to include in the neighbor list and the mobile terminals are signaled to measure all theoretically possible neighbors. One drawback with the mobile terminals determining the neighbors to include in the neighbor list is that a substantial measurement time period is required to guarantee that the entire serving cell area has been covered by the measurement data. Co-owned US Provisional Patent Application No. 60/850,108, filed on October 6, 2006 and hereby incorporated by reference (now US 11/973,030, filed on October 4, 2007 and entitled "Apparatus, Method and Computer Program Product Providing User Equipment Self-Terminating Reporting Technique"), describes that the UEs determine individually to limit their measurement reports based on certain criteria. Co-owned US Provisional Patent Application No. 60/881 ,287, filed on January 18, 2007 and hereby incorporated by reference (now US 12/009,399, filed January 18, 2008 and entitled "Network Oriented Control System for Self-Configuration and Self-Optimization Measurements"), describes the network making decisions concerning the UE-generated measurement reports, which enables restricted requests for the mobile terminal to measure and report.

[0005] As can be seen at document R2-071529; 3GPP TSG RAN WG2#57bis, St. Julian, Malta, 26-30 March 2007, by China Mobile, NTT DoCoMo, Orange, Telecom Italia, Vodafone Group (attached as Exhibit A to the priority document US Provisional Patent Application No. 60/936,883), E-UTRAN requirements include support for access restrictions, to efficiently support a large amount of e.g. Home-eNBs. Access restrictions include CSGs/private networks, where only subscribers of the closed group are allowed access. The term Home- eNB refers to a BS of the private network.

[0006] One requirement is that access restrictions must be capable of being handled on the cell level (e.g. Home-eNB) efficiently and without need for an excessive amount of signaling. Additionally it is also required that access restrictions are taken into account in the UE's Idle mode (as opposed to the UE's Active mode) in the sense that UEs with access restrictions will not even camp on a cell on which access is restricted.

[0007] Specifically, that requirement for cell reselection can be seen at document R2- 072139; 3GPP TSG RAN WG#58, Kobe, Japan, 7-11 May 2007, by Vodafone Group (attached as Exhibit B to the priority document US Provisional Patent Application No. 60/936,883) as: "A UE should not camp on or access a CSG Cell if it is not part of the User Group which is allowed to access that CSG Cell."

[0008] Several proposals have been made on how this can be achieved based on UE stored information combined with access restriction information read by the UE during mobility (handover or cell re-selection) procedures. For example, access restrictions could be read by the UE from the target cell's broadcast channel. But reading the neighbor cell's broadcast channel might not always be a straightforward procedure for a UE having an active data transmission or being in RRC-CONNECTED mode. If a neighbor cell is placed on a frequency other than that of the serving cell (inter-frequency measurements), the UE may need to perform gap-assisted measurements and this procedure would then also need to be able to support gaps for the purpose of reading the neighbor cells' broadcast channel BCH (or BCCH broadcast control channel). Additionally, it could also put further requirements on the BCH/BCCH of the system in the sense that the BCH/BCCH coverage would have to be assured well enough to provide reception probability for mobility procedures.

[0009] From that same document R2-072139: "The system shall support handover between CSG Cells and any eNodeB (E-UTRAN) or RNC (UTRAN) or BSS (GERAN) or with another CSG Cell of the same or different CSG". This requirement basically means that mobility and therefore measurements carried out while being camped in a Home-eNB needs to be supported on the same level as when the UE is camped on macro layer cells (e.g., the regular non-private network cells). The requirement also indicates that system information broadcast in a Home-eNB needs to support information indicating a more or less detailed neighbor cell list for support of inter-frequency and/or inter-RAT (radio access technology) measurements and mobility.

[ooio] Such functionality would require that someone or some sort of configuration of the Home-eNB needs to be done. This could either be done by person (on site, in operations and maintenance of network equipment, etc), but it cannot be expected that the operator of the Home-eNB has the knowledge needed concerning the macro layer layout. Add to this that to enable a wide range of private networks the Home-eNBs should be inexpensive and require a minimum of setup effort. Configuration of Home-eNB's should therefore be kept at a minimum.

[ooii] One alternative is of course to use auto/self-configuration algorithms in the Home- eNB, but this means additional features to be supported and tested leading to an increase in complexity of the Home-eNB.

[0012] If mobility is supported to the same level by the Home-eNBs as on the macro layer as above, then the cell identification and measurement ruies needs to be similar on Home-eNB cells and on the macro layer. In order to simplify the configuration of the Home-eNB's (e.g. consider the Home eNB to be similar to a WLAN type device), one might suggest that the Home-eNB might not distribute any neighbor lists at all. This would mean that the Home-eNB would not distribute intra-frequency or any inter-frequency or any inter-RAT neighbor lists.

[0013] These considerations would basically either disable these measurements or make them very inefficient from a UE point of view in the sense that they would always be active - which would be costly in theoretical throughput and UE power consumption.

[ooi4] Current agreements and working assumption on neighbor list distribution and neighbor cell system information reading afterthe May 2007 meeting referenced at document R2-072139 is summarized as follows:

• The network does not have to deliver an intra-frequency neighbor cell list. Identification of intra-frequency neighbour cells relies on the UE autonomously performing cell identification.

• The network will provide a neighbor list for inter-frequency and inter-RAT cases. Details on what is delivered is not yet decided but for inter- frequency it could just be a center frequency and for inter-RAT it could be as already provided in legacy systems.

• The UE may have to read system information from intra-frequency cells for mobility purposes.

• The UE need not read system information from inter-frequency or inter- RAT cells. [0015] As above, the current E-UTRAN agreement is that the eNB does not need to distribute an intra-frequency neighbor cell list but the eNB may rely on the UE to autonomously search and identify intra-frequency cells. This means that the UE will perform intra-frequency cell searches according to some performance requirements -which results in continuous intra-frequency cell searches with certain time intervals. However it might make sense sometimes to disable the UE's intra-frequency cell searches.

[0016] Not distributing any inter-frequency or inter-RAT neighbor lists at all would at least raise the following issues:

« When should the UE actually perform measurements?

• What should the UE measure [inter-frequency/inter-RAT (GSM, UMTS) etc.]

[0017] Document R2-072139 also states: "It shall be possible to minimise the quantity of measurements which UEs perform on CSG Cells, if the UE does not belong to the User Group of a specific CSG Cell". This additionally indicates that there are some requirements from network operators that the UE should be able to minimize or even eliminate reporting of neighbor cells on which the UE has restricted access (meaning no access). And if it is not required for the UE to somehow identify possible private cells, then the UE would be reporting all possible ceiis in the measurement reports aithough it may not have any access rights to some or all of those cells.

[0018] Basic agreements on system information broadcast and distribution tends to indicate that not all access restriction information can or will be located in the primary broadcast channel P-BCH (alternatively termed the master information block MIB). This basically means that the UE needs to read, from the neighbor cell itself, any access restriction information prior to moving to that or another neighbor cell (either required by the specification or for optimized functionality). This means that the UE would need to read the dynamic broadcast channel D-BCH.

[0019] In the basic GSM system the UE will read neighbor cell system information priorto cell reselection (handover). The information read from neighbor cells includes basic access restriction information like cell barring and location area LA. Improved procedures for GSM/GPRS have been implemented that allow for delivering the part of this neighbor cell information from the serving cell broadcast information.

[0020] Further, requiring the UE to read the BCH from all neighbors may also have a negative impact on basic mobility in the form of delayed handover in the RRC-CONNECTED state plus increased UE power consumption in both Idle and Active state.

[0021] And when considering private networks (e.g., a corporate or university campus network which is accessible by many users and covers a larger area such as cells that should be prioritized by specific subscribers) there is not currently a method where the UE would know from the source cell if there is this kind of private network in the vicinity, thus indicating that the UE needs to start searching for and measuring such cells. As certain private networks may cover quite a large area it could be challenging for the UE memory consumption to try to memorize where such cells may be located. Alternatively, if the UE does not memorize location information then the UE is required to read system information from all possible identified cells on a specific frequency (the private network frequency), because the UE is supposed to identify cells in order to know whether it should prioritize camping on those.

[0022] What is needed is an approach to address these interrelated issues that arise from both more densely packed eNBs and the existence of cells to which certain UEs will not have access. Such a solution should be efficient in signaling since this is control signaling and repeated among all UEs in all cells, and should also not be wasteful of UE power or memory resources, which are limited.

SUMMARY:

[0023] In accordance with an exemplary embodiment of the invention is a method that includes receiving at a user equipment an indication that another cell apart from a serving network cell is a private network cell, and determining that the user equipment is restricted from accessing the another ceil, and the user equipment excluding measurements of the another cell from an uplink measurement report that it sends to the serving network cell based on the determining.

[0024] In accordance with another exemplary embodiment of the invention is an apparatus that includes a receiver, a processor and a transmitter. The receiver is configured to receive an indication that another cell apart from a serving network ceil is a private network cell. The processor is configured to determine that the apparatusis restricted from accessing the another cell, and based on the determining the processor is configured to exclude the another cell from measurements of adjacent cells. The transmitter is configured to send to the serving network cell an uplink measurement report of the adjacent cells, the uplink measurement report excluding any measurement information of the another cell. In various embodiments such an apparatus may be a portable user equipment, or an integrated circuit/chipset that is adapted for use within a user equipment.

[0025] In accordance with still another exemplary embodiment of the invention is a memory storing a program of computer readable instructions that, when executed by a processor, cause actions that are directed toward determining cells for measurement reports. In this embodiment the actions include receiving at a portable apparatus an indication that another cell apart from a serving network cell is a private network cell, and determining that the portable apparatus is restricted from accessing the another cell, and then based on the determining, excluding measurements of the another cell from an uplink measurement report that the portable apparatus sends to the serving network cell.

[0026] In accordance with yet another exemplary embodiment of the invention is an apparatus that includes receiver means such as for example a wireless receiver, processing means such as for example a digital signal processor, and sending means such as for example a wireless transmitter. The receive means and the sending means may be embodied for example in a single transceiver. The receive means is for receiving an indication that another cell apart from a serving network cell is a private network cell. The processing means is for determining that the apparatusis restricted from accessing the another cell, and based on the determining the processing means is further for excluding the another cell from measurements of adjacent cells. The sending means is for sending to the serving network cell an uplink measurement report of the adjacent cells, the uplink measurement report excluding any measurement information of the another cell. In various embodiments such an apparatus may be a user equipment, or an integrated circuit/chipset that is adapted for use within a user equipment.

[0027] In accordance with another exemplary embodiment of the invention is a method that includes determining that a user equipment is restricted access from another network cell that is a private network cell, signaling from a serving network cell an indication that another cell is a private network cell, and receiving from the user equipment an uplink measurement report of adjacent cells, wherein the uplink measurement report excludes measurements of the another cell.

[0028] In accordance with still another exemplary embodiment of the invention is an apparatus that includes a processor, a transmitter and a receiver. The processor is configured to determine that a user equipment is restricted access from another network cell that is a private network cell. The transmitter is configured to signal an indication that another cell is a private network cell. The receiver is configured to receive from the user equipment an uplink measurement report of adjacent cells, wherein the uplink measurement report excludes measurements of the another cell. In various embodiments such an apparatus may be a network node such as a base station/eNodeB, or an integrated circuit/chipset that is adapted for use within such a network node.

[0029] These and other aspects of the invention are detailed with more particularity below.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0030] Figure 1 is a schematic representation of a cellular telecommunications system showing a cluster of adjacent cells with mobile terminals MT in each, where any of the cells ffidy restrict ciccess to some of the deμicted MTs.

[0031] Figure 2 is a schematic representation similar to Figure 1 where a MT maintains in a !oca! memory a neighbor list of information for other adjacent/neighbor cells.

[0032] Figure 3 is a high level block diagram of various devices used in carrying out various aspects of the invention.

[0033] Figure 4 is a signaling diagram between a serving network cell and one user equipment/mobile terminal showing alternative ways for access restriction information to be given to the UE according to embodiments of the invention.

[0034] Figure 5 is a signaling diagram similar to Figure 4 showing how access restriction information can be signaled to the target network cell according to an embodiment of the invention. DETAILED DESCRIPTION:

[0035] Further to the background presented above, Figure 1 shows a cluster of cells each with a BS/eNB/access point and a plurality of MTs/UEs. Any particular one of the MTs/UEs may be in or moving toward or moving adjacent to a private network/Home-eNB for which it does not have access rights and will not be granted access. At Figure 2 is a neighbor list that the MT/UE maintains in order to avoid excessive measuring and searching for inter-frequency and inter-RAT cells. A private network/CSG may span one or more cells.

[0036] Embodiments of the invention address some of the above-mentioned challenges in several aspects summarized here. To provide information as to which celis restrict access to the UE, the serving cell/eNB sends to the UE access restriction information prior to the UE being handed over to a target cell/eNB. [Note that while the description of handovers below is in the context of network commanded handovers (forward handovers or FHO), E-UTRAN also provides for handovers executed by the UE itself (backward handovers BHO) and these teachings are not restricted to only one of those types of handovers or only to E-UTRAN.] The UE sends to the target cell/eNB the access restriction information after the handover.

[0037] In another aspect the serving cell/eNB identifies by location area LA or tracking area TA (or similar area-specific iists) in a neighbor ceii iist that it sends to a UE any private networks/eNBs that are in that neighbor list. The eNB may also or alternatively indicate in the neighbor cell list if the whole frequency layer is usage-restricted. The UE receives that/those indicators, and knows from them whether it is required to measure that layer or the individually indicated cells. For the case where a particular UE is registered and has access rights, the UE 10 may still be required to measure and report, but potentially not for cells that restrict that UE.

[0038] In another aspect, in order to facilitate handovers without signaling neighbor lists in each cell, the UE retains in a local memory a neighbor list derived in a previous cell when entering a Home-eNB/CSG cell for which it does have access rights. The CSG cell can broadcast an indicator in its system information SI that the UE 10 is to use a neighbor cell list from a previous cell. For the case where the immediately previous cell is also restricted or also indicated by its SI that the UE is to carry over its previous neighbor cell list, that same neighbor cell list is again carried through the second previous cell, and so on until the UE encounters a new cell for which it has access and can get a new neighbor list. The UE carries its neighbor cell list from the latest camped cell. The UE receives SI in the new cell, which may distribute its own neighbor cell list. If the new cell does not distribute its own neighbor cell list it may indicate to the UE through its SI that the UE shall use its previous neighbor cell list. There may also be an additional indicator to tell the UE whether or not to perform intra-frequency cell searches while the UE 10 is in the cell which is sending the indicator.

[0039] Before delving into more particular details, reference is made first to Figure 3 for illustrating a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention. In Figure 3 a wireless network 9 is adapted for communication with a UE 10 via a node B 12 (e.g., base station or eNB). The network 9 may include a higher controlling node genericaliy shown as a gateway GW 14, which may be referred to variously as a radio network controller RNC, a user plane entity UPE, a mobility management entity MME, or a system architecture evolution gateway SAE- GW. The GW 14 represents a network node higher in the network than the eNB 12.

[0040] The UE 10 includes a data processor (DP) 10A, a memory (MEM) 10B that stores a program (PROG) 10C, and a suitable radio frequency (RF) transceiver 10D for bidirectional wireless communications with the eNB 12, which also includes a DP 12A, a MEM 12B that stores a PROG 12C, and a suitable RF transceiver 12D. The eNB 12 may be coupled via a data path 16 (e.g., lub or S1 ) to the serving or other GW 14. The eNB 12 and the UE 10 communicate over a wireless link 15, each using one or more antennas 12E, 10E. At least one of the PROGs 10C and 12C is assumed to include program instructions that, when executed by the associated DP, enable the electronic device to operate in accordance with the exemplary embodiments of this invention, as will be discussed below in greater detail.

[0041] In general, the exemplary embodiments of this invention may be implemented by computer software executable by the DP 10A of the UE 10 and the other DPs, or by hardware, or by a combination of software and/or firmware and hardware. The interactions between the major logical elements should be obvious to those skilled in the art for the level of detail needed to gain an understanding of the concept of the invention. It should be noted that the invention may be implemented with an appropriate signal processor such as shown in Figure 3, a digital signal processor or other suitable processor to carry out the intended function of the invention, including a central processor, a random access memory RAM, read only memory ROM, and input/output ports for coupling to other components in the network element/e-NB or UE in which this processor is disposed.

[0042] In general, the various embodiments of the MT/UE 10 can include, but are not limited to, cellular telephones, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions.

[0043] The MEMs 10B and 12B may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The DPs 10A and 12A may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples.

[0044] At least one of the memories is assumed to include program instructions that, when executed by the associated processor/CPU, enable the electronic device to operate in accordance with the exemplary embodiments of this invention, as summarized above and detailed further below. As such, the exemplary embodiments of this invention may be implemented at least in part by computer software executable by the controller/CPU of the network element 12 or UE 10, or by hardware, or by a combination of software and hardware.

[0045] It is anticipated that at least some aspects of this invention are appropriate to be written into a wireless network protocol or standard. Embodiments of the invention can reside wholly in software.

[0046] First consider the aspects of the invention concerning access restriction information. In the basic GSM system the UE 10 will read neighbor cell system information prior to cell reselection/handover. The information read from neighbor cells includes basic access restriction information like cell barring and LA. Improved procedures for GSM/GPRS have been implemented and allow for delivering the part of this neighbor cell information from the serving cell's broadcast information.

[0047] Now, in one aspect of the invention the network/eNB 12 updates or otherwise instructs the UE 10 about possible access restrictions in dedicated DL signaling. This dedicated signaling can be sent in response to a UE measurement report, for example. Based on the UE measurement report the network/eNB 12 may reply either in a separate message or include in a HO command message, information concerning neighboring cell(s) access restriction. Access restriction information in this sense could e.g. be location area LA of neighboring cell(s), barring information, 'private' ceil indication or simply some indication that a certain cell is access restricted.

[0048] The network/eNB 12 can indicate any identity (e.g. tracking area TA identity) of private networks/cells in the neighbor cell list it distributes to the UE 10. The information could be in the part of the neighbor list where properties of the private network/cell frequency are indicated. In a simple form, this aspect of the invention can be implemented in E- UTRAN/LTE if the private network/cell is deployed on another (center) frequency (or separate frequency layer) than the public non-restricted network. In this case the serving cell inter- frequency neighbor cell list would simply list the (center) frequency of the private network/cell and the identity (LA/TA) associated with the private network/ceii. This information can then be utilized by the UE 10 in both idle and active modes to avoid measurement/identification of inter-frequency cells in cases when UE 10 would not have access rights for those cells.

[0049] A current assumption in E-UTRAN is that all private networks have been allocated a tracking area id (TAJD), which would by the above example be indicated in the neighbor cell list. As the UE 10 would know whether it has access to the private network indicated in the neighbor cell list- either because it has been registered to such a private network earlier or the UE 10 has received and stored some whitelist (allowed list) of identities of private networks to compare against - the UE 10 will use the identity in the neighbor cell list to know when or if it should start to measure/identify a restricted cell on that frequency. Any unique identifier for the cell may be used, such as TA, LA, Cell-ID and the like, or even a newly defined identifier for the cell. [0050] It is noted that the private network indicated above can also be indicated by the regular Home-eNB; the network would organize Home-eNBs so that a cell in a geographically same area would have the same TA and indicate TA_ID(s) of nearby Home-eNBs in the neighbor cell list (or any information on the broadcast channels). Thus the UE 10 could use this information similarly to private network cases to avoid measuring/looking for Home-eNBs all the time when it hears a frequency related to the Home-eNBs.

[0051] In this way the UE 10 would not be reporting (sending a measurement report) for those cells for which UE does not have access rights. The UE 10 receives the dedicated access restriction information in the dedicated downlink signaling, determines whether it is restricted from the ce!l(s) that is/are indicated as restricted, and only if the determination is that the UE 10 has access does the UE perform measurements of that/those celi(s) and sends measurement reports of that measurement data.

[0052] Similarly, the UE 10 can also or alternatively inform the eNB 12 of its access restrictions. For example, during UE mobility (e.g. in the RRC_CONNECTED state) the UE 10 includes possible access restrictions to be applied by the UE. This may be sent for example in the handover (HO) signaling, such as in the HANDOVER_CONFIRM message that the UE sends to the new serving cell/eNB 12 after a cell change.

[0053] There is not always the need to transfer the access restrictions in the regular air interface 15 because the source eNB 12 can transfer the UE's access restriction in the HO context.

[0054] Figure 4 illustrates these aspects of the invention in an exemplary signaling protocol. The UE 10 and serving eNB 12 are depicted, and the UE 10 is in the RRC_CONNECTED state 402 in which mobility/handovers are performed using UE assisted (measurement reporting) and network controlled (FHO) handover procedures. The eNB 12 broadcasts system information 404, which includes general measurement rules to be applied by all UEs camped on the eNB's cell. At some trigger event 406 (many are known in the art: periodic, signal strength below a threshold, etc.) the eNB 12 instructs the UE 10 that it is to send a measurement report to the network, the UE 10 generates at 408 the measurement report according to the rules at 404 and the UE 10 sends at 410 the measurement report in the uplink to the eNB 12. In this instance the measurement report includes a mix of intra- frequency, inter-frequency and possibly inter-RAT neighbor cells. Based on this information the network evaluates 412 possible access restriction settings for the included cells (and possibly also other non-reported cells for which it received information from other UEs). After evaluating the information 412 the network/eNB 12 may send new/updated access restriction information to the UE 10. A UE 10 receiving such information stores and applies this information according to the given rules for applying access restrictions in the network. At option A of Figure 4, that update to access restriction information is given in a separate message apart from a HO related message, such as in a measurement command message 414. The network/eNB 12 can alternatively provide those access restrictions already in the HO procedures before the UE 10 reports any cells to the network/eNB 12. Shown at option B by example is for the network/eNB 12 to include those access restriction updates in the handover command 416, where the updated access restriction requirements are for the target cell to which the handover command relates (includes the target cell information),

[0055] When the network/eNB 12 informs those access restrictions forthe UE 10, it can deny or restrict access to a whole frequency layer/RAT if the network determines or knows that there are no cells where the UE has access rights on those frequencies. A single bit in the neighbor cell list can be used to inform the UE 10 that the whole RAT/frequency layer is access restricted. The network/eNB 12 can inform each access-restricted cell separately if the restriction is not RAT-wide, or it may just inform/signal the UE 10 to report only those cells where the UE 10 is subscribed i.e. has access rights. Also, this information is available forthe UE 10 in both the idle and the active mode, so it can be utilized by the UE in both states.

[0056] Where the network/eNB 12 indicates in the neighbor cell list that a whole frequency layer is reserved for Home-eNB/CSG usage, the UE 10 then knows whether it is required to measure that layer at all or if it needs to use any special handling when measuring/evaluating/ranking cells on that layers. The UE 10 is not required to measure and report if the UE 10 is not registered to any of the CSG cells in that frequency layer/RAT. Now, for a restricted access single-cell network, the eNB 12 can inform the UE 10 in a message that single-cell network is access restricted and, so long as the UE 10 knows/determines that it is not a subscriber to that restricted cell, the UE 10 knows that it does not need to perform intra-frequency cell searches.

[0057] The aspect of the invention where the UE 10 informs the network of its possible access restrictions may be implemented as follows and as shown by example at Figure 5. As with Figure 4, the context is the UE 10 being in the RRC_CONNECTED state 402, and other like reference numbers indicate like signaling/actions as detailed with respect to Figure 4. At Figure 5 is option C: after the UE 10 has received the handover command 518 from the network/eNB 12 and changed 520 to the target cell/eNB 12 as indicated in the Handover command message, the UE 10 will send a handover_confirm message 522 back to the network (but this time to the target eNB 12 since changeover 520 has occurred) in order to confirm its presence and the success of the cell change. The handover_confirm message 522 is in this embodiment enlarged (as compared to the similar prior art message) to include possible access restrictions to be applied by the UE 10. The target eNB 12 is thereby informed as to which private networks/RATs the UE 10 recently handed over is restricted or authorized access.

[0058] Several advantages are seen with the embodiments illustrated by Figures 4-5.

• For intra-frequency cells when no neighbor cell list is available this approach can be used for restricting access for certain users.

• Flexible and UE specific information can be given.

• Easy update of access restriction information from network to UE.

• UE would not always need to read access restrictions from neighbors (this is useful in some heavy load scenarios).

[0059] While this represents more control signaling, the additional signaling is seen to be much less than would be necessary if one simply extended the wholesale downloading of neighbor lists to the private network aspects of E-UTRAN.

[0060] Now the above implementations rely on neighbor lists, which as noted in the background section become difficult in E-UTRAN and other systems having private networks as compared to an all-public network. Merely extending the way that legacy all-public systems handled neighbor lists would also add greatly to signaling overhead, often with little benefit as to the private network aspects. To minimize the configuration effort of Home- eNB's, according to an aspect of this invention the UE 10 is required to remember (to keep stored locally in its MEM 10C) the macro layer cell information when entering the Home-eNB. In a first embodiment this is the last received neighbor list or a combination of neighbor cells and identified cells. In a second embodiment it is the list of last identified and/synchronized cells prior to entering the Home-eNB/CSG cell. In a third embodiment it includes channel information, e.g. frequency band or carrier, of intra- and inter-systems supported by the UE 10. [0061] This aspect is seen to be particularly advantageous for limited size CSG/Home-eNB networks (e.g., 1 or 2 Home-eNB cells). A bit more extensive and tailored list may need to be constructed for retaining in local storage for the case of larger private networks, but the concept can be readily combined with other proposed self/auto-configuration and self- optimization algorithms and schemes.

[0062] It is noted that while both the Active/RRC-CONNECTED state and idle state are mentioned above, it will be understood that the HO messages are relevant only for the RRC_CONNECTED/active state.

[0063] Above it is described that the Home-eNB 12 has the option of not transmitting any inter-frequency or inter-RAT neighbor ceil iists to the UE 10, and also an option of notifying the UE 10 to stop intra-frequency measurement if the CSG/Home-eNB contains only one ceii. At first blush this might seem a bit counterintuitive, but they are meant for different purposes and most advantageously used at different times and under different circumstances. By the UE 10 importing the neighbor cell list it would know what to measure. When to measure will depend on triggers and possible timers, as seen in Figures 4-5. Using a bit indicating to the UE 10 that it is not to measure intra-frequency cells is most beneficially used in a single restricted cell environment, which allows the UE 10 to skip the intra-frequency cell searches in a simple way. This may improve UE power consumption and ensure that the UE 10 doesn't unnecessarily identify cells which are not accessible to it. This also aids in reducing event triggers and possible unnecessary measurement reporting.

[0064] Where the one-bit indication to the UE 10 allows forthe eNB 12 to indicate to the UE 10 to use the imported neighbor list or not, the eNB will distribute a neighbor cell list else the UE 10 will have no neighbor list at all. For a UE 10 in the RRC-CONNECTED state the UE 10 would preferably need a neighbor cell list for ensuring mobility to a satisfactory level. But if mobility isn't really wanted unless service from current eNB is lost (WLAN style) then the option forthe UE 10 not having any neighbor list is possible (e.g., a one-bit indication that the UE 10 is not to use the imported neighbor list and no neighbor list distributed by the eNB 12). This would be advantageous for the UEs in the idle mode.

[0065] The different aspects of the invention detailed above may be summarized as the following steps. i) The network instructs the UE to perform measurement ii) The UE reports the measurement including a mix of intra-frequency, inter-frequency and possibly inter-RAT neighbor cells. iii) Based on the UE reports, the network updates and sends to UE the access restriction information in the neighboring cell list. This list can be conveyed in a HO message or in a new separate message. Note that the access restriction information does not have to be in the neighbor list; that is simply a convenient place to put the information. Other information elements, even newly defined ones, may be used. As an alternative, the network can also provide the access restriction information before the UE 10 reports any cells to the network (by skipping the first two steps). So if the network/eNB 12 knows the UE 10 is entering a cell/eNB/base station which covers an area with cells which includes some access restrictions for the UE 10, the eNB 12 now has the option to send this information to the UE 10 at the point of entering the ceii. The Home-eNBs of a private network may transmit neighbor celi lists. Inclusion of access restriction information into the neighbor ceil list is advantageously used in the macro layer (non-restricted network) for aiding the UE 10 cell search and possibility to skip cell searches. On the other hand, the option for home-eNBs not transmitting the neighbor cell list at all in order to simplify the configuration of home-eNB as well the UE's behavior necessarily relates to Home-eNB usage rather than the macro layer. iv) The UE is allowed to inform its possible access restriction information to the eNB, which eases the burden of the X2 (eNB to eNB) interface during a handover.

[0066] i he network uses the UE measurement report not primarily to indicate access restrictions in the broadcast information, but to limit the measurement reporting and measuring of cells to which the UE 10 does not have access. If the UE 10 just reports cells the network may then, based on the cell identification in the measurement report, inform the UE 10 about possible access restrictions. So the report is most advantageously used for informing network about which cells the UE is monitoring, and the network then can stop the UE 10 from submitting measurement reports for cells to which it might be measuring butfrom which it is restricted having access.

[0067] The UE can do the measurement before the network sends it the access information (e.g., the frequency of the neighboring cells). The UE 10 will know which frequencies to search neighbor cells based on broadcast information received in the current serving cell. The UE 10 can perform cell search and identification and signal level measurements without reading the neighboring cell's common broadcast information, where the information concerning possible access restriction is currently understood to be broadcast. [0068] The invention involves cooperation between elements of a communication system. Examples of a wireless communication system include implementations of GSM (Global System for Mobile Communication) and implementations of UMTS (Universal Mobile Telecommunication System). These elements of the communication systems are exemplary only and does not bind, limit or restrict the invention in any way to only these elements of the communication systems since the invention is likely to be used for B3G systems. Each such wireless communication system includes a radio access network (RAN). In UMTS, the RAN is called UTRAN (UMTS Terrestrial RAN). A UTRAN (or Evolved UTRAN) includes one or more Radio Network Controllers (RNCs, or generically a controller of a radio network), each having control of one or more Node Bs (e-Node Bs), which are wireless terminals configured to communicatively couple to one or more UE terminals. The combination of an RNC and the Node Bs it controls (or their equivalents in other systems) is called a Radio Network System (RNS). A GSM RAN includes one or more base station controllers (BSCs), each controlling one or more base transceiver stations (BTSs). The combination of a BSC and the BTSs it controls is called a base station system (BSS). These teachings are applicable to those communication systems where there exist private networks/cells that are not open to non- subscribers/non-members

[0069] Based on the foregoing it should be apparent that the exemplary embodiments of this invention provide a method, apparatus and computer program ρroduct(s) for a network to execute the signaling as shown in Figures 4-5 and respond as described with reference to those figures, though not necessarily limited to the exemplary messages noted there.

[0070] The exemplary embodiments of this invention further provide a method, apparatus and computer program product(s) for a UE to execute the signaling as shown in Figures 4-5 and respond as described with reference to those figures, though not necessarily limited to the exemplary messages noted there. Further, the UE will store locally a neighbor list from a previous cell while in a new cell and use that previously stored neighbor list for determining measurement reports and neighboring cell information.

[0071] In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the exemplary embodiments of this invention may be illustrated and described as block and signaling diagrams, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0Q72] As such, it should be appreciated that at least some aspects of the exemplary embodiments of the inventions may be practiced in various components such as integrated circuit chips and modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be fabricated on a semiconductor substrate. Such software toois can automatically route conductors and locate components on a semiconductor substrate using well established rules of design, as well as libraries of pre-stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, orthe like) may be transmitted to a semiconductor fabrication facility for fabrication as one or more integrated circuit devices.

[0073] Various modifications and adaptations to the foregoing exemplary embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this invention.

[0074] Furthermore, some of the features of the various non-limiting and exemplary embodiments of this invention may be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.

Claims

CLAIMS: We claim:

1. A method comprising: receiving at a user equipment an indication that another cell apart from a serving network cell is a private network cell; determining that the user equipment is restricted from accessing the another cell; and the user equipment excluding measurements of the another cell from an uplink measurement report that it sends to the serving network cell based on the determining,

2. The method of claim 1 , wherein the indication is received at the user equipment in dedicated downlink signaling from the serving network ceil.

3. The method of claim 2, wherein the dedicated downlink signaling comprises a handover command and is in response to a previous uplink measurement report that the user equipment sends to the serving network cell in response to satisfying a measurement trigger received from the serving network cell for a measurement report.

4. The method of claim 1 , wherein determining that the user equipment is restricted comprises determining in the user equipment that the another cell is not within a list that is stored within a local memory of the user equipment, said list comprising at least private cells for which the user equipment is allowed access.

5. The method of claim 1 , wherein the indication is received in system information that is broadcast from the another cell.

6. The method of claim 1 , further comprising reporting to the serving network cell that the user equipment is restricted from accessing the another cell.

7. The method of claim 6, wherein reporting to the serving network cell that the user equipment is restricted from accessing the another cell is sent with a handover confirm message.

8. The method of claim 1 , wherein the indication that another cell apart from the serving network cell is a private network cell is received from the serving network cell in a neighbor list, and wherein the user equipment excluding measurements of the another cell from the uplink measurement report comprises sending to the serving network cell at least one measurement report of at least one further cell of the neighbor list for which it has been determined that the user equipment is not restricted access.

9. The method of claim 8, wherein the indication is that an entire frequency layer in which the another cell operates is restricted access, and wherein excluding measurements of the another cell comprises excluding measurements of all cells operating within the frequency layer.

10. The method of claim 8, further comprising the user equipment storing in a local memory the received neighbor list and retaining the stored neighbor list as valid while transiting the another cell.

11. The method of claim 1 , further comprising sending to a new serving network cell a handover confirm message that comprises an indication that the user equipment is restricted access to the another cell.

12. A apparatus comprising: a receiver coniigureu io receive an inuicsuon mSi anomer ceu span irom a serving network cell is a private network cell; a processor configured to determine that the apparatus is restricted from accessing the another cell, and based on the determining to exclude the another cell from measurements of adjacent cells; and a transmitter configured to send to the serving network cell an uplink measurement report of the adjacent cells, the uplink measurement report excluding any measurement information of the another cell.

13. The apparatus of claim 12, wherein the receiver is configured to receive the indication in dedicated downlink signaling from the serving network cell.

14. The apparatus of claim 13, wherein the dedicated downlink signaling comprises a handover command and is in response to a previous uplink measurement report that the transmitter sends to the serving network cell in response to satisfying a measurement trigger for a measurement report that the receiver received from the serving network cell.

15. The apparatus of claim 12, further comprising a memory storing a list comprising at least private cells for which the apparatus is allowed access; wherein the processor is configured to determine that the apparatus is restricted by determining that the another cell is not within the list.

16. The apparatus of claim 12, wherein the receiver is configured to receive the indication in system information that is broadcast from the another cell.

17. The apparatus of claim 12, wherein the transmitter is further configured to send an indication to the serving network ceil that the apparatus is restricted from accessing the another cell.

18. The apparatus of claim 17, wherein the transmitter is configured to send with a handover confirm message the indication that the apparatus is restricted from accessing the another cell.

19. The apparatus of claim 12, wherein the receiver is configured to receive, from the serving network cell in a neighbor cell list, the indication that another cell apart from the sen/ing network cell is a private network cell, and wherein the uplink measurement report comprises at least one measurement report of at least one further cell of the neighbor list for which it has been determined that the apparatus is not restricted access.

20. The apparatus of claim 19, wherein the indication is that an entire frequency layer in which the another cell operates is restricted access, and wherein the processor is configured to exclude measurements of the another cell by excluding measurements of all cells operating within the frequency layer.

21. The apparatus of claim 20, further comprising a memory; wherein the processor is configured to store in the memory the received neighbor list and to retain the stored neighbor list as valid while the apparatus transits the another cell.

22. The apparatus of claim 12, wherein the transmitter is further configured to send to a new serving network cell a handover confirm message that comprises an indication that the apparatus is restricted access to the another cell

23. A memory storing a program of instructions that when executed by a processor cause actions directed toward determining cells for measurement reports, the actions comprising: receiving at a portable apparatus an indication that another cell apart from a serving network cell is a private network cell; determining that the portable apparatus is restricted from accessing the another cell; and based on the determining, excluding measurements of the another cell from an uplink measurement report that the portable apparatus sends to the serving network cell.

24. A apparatus comprising: receive means for receiving an indication that another cell apart from a serving network cell is a private network cell; processing means for determining that the apparatus is restricted from accessing the another cell, and based on the determining for excluding the another cell from measurements of adjacent cells; and sending means for sending to the serving network cell an uplink measurement report of the adjacent cells, the uplink measurement report excluding any measurement information

25. A method comprising: determining that a user equipment is restricted access from another network cell that is a private network cell; signaling from a serving network cell an indication that another cell is a private network cell; and receiving from the user equipment an uplink measurement report of adjacent cells, wherein the uplink measurement report excludes measurements of the another cell.

26. The method of claim 25, wherein the signaling is dedicated downlink signaling to the user equipment and comprises a handover command that is sent in response to a previous uplink measurement report received from the user equipment in response to satisfying a measurement trigger that the serving network cell specifies.

27. The method of claim 26, wherein the indication in the dedicated downlink signaling is a restriction indication that is specific to the user equipment.

28. The method of claim 25, wherein the signaling comprises dedicated downlink signaling to the user equipment and comprises a neighbor list.

29. The method of claim 29, wherein the indication is that an entire frequency layer in which the another cell operates is restricted access.

30. A apparatus comprising: a processor configured to determine that a user equipment is restricted access from another network ceil that is a private network cell, a transmitter configured to signal an indication that another cell is a private network cell; and a receiver configured to receive from the user equipment an uplink measurement report of adjacent cells, wherein the uplink measurement report excludes measurements of the another cell.

31. The apparatus of claim 30, wherein the signaling comprises dedicated downlink signaling to the user equipment and comprises a handover command that the transmitter is configured to send in response to the receiver receiving from the user equipment a previous uplink measurement report.

32. The apparatus of claim 31 , wherein the indication in the dedicated downlink signaling is a restriction indication that is specific to the user equipment.

33. The apparatus of claim 30, wherein the signaling comprises dedicated signaling to the user equipment and comprises a neighbor list.

34. The apparatus of claim 33, wherein the indication is that an entire frequency layer in which the another cell operates is restricted access.