WO2013138995A1

WO2013138995A1 - Method and apparatus for dormant state determination

Info

Publication number: WO2013138995A1
Application number: PCT/CN2012/072626
Authority: WO
Inventors: Yi Zhang; Lei Du; Ioannis Maniatis
Original assignee: Nokia Siemens Networks Oy
Priority date: 2012-03-20
Filing date: 2012-03-20
Publication date: 2013-09-26

Abstract

A method and apparatus for dormant state determination are disclosed. The method comprises determining for at least one type of cell event, the number of occurrences of said cell event, and causing information on said number of occurrences to be sent to a base station. A method comprising receiving said information for at least one user equipment, and using said information to determined if said user equipment should be in a dormant state is also disclosed.

Description

METHOD AND APPARATUS FOR DORMANT STATE DETERMINATION

This disclosure relates to a method and apparatus and in particular but not exclusively to a method and apparatus which may be used for dormancy. A communication system can be seen as a facility that enables communication sessions between two or more nodes such as fixed or mobile devices, machine-type terminals, access nodes such as base stations, servers and so on. A communication system and compatible communi- eating entities typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. For example, the standards, specifications and related protocols can define the manner how devices shall communicate, how various aspects of communications shall be implemented and how devices for use in the system shall be configured.

A user can access the communication system by means of an appropriate communication device. A communication device of a user is often referred to as user equipment (UE) or terminal. A communication device is provided with an appropriate signal receiving and transmitting arrangement for enabling communications with other parties. Typically a device such as a user equipment is used for enabling receiving and transmission of communications such as speech and content data.

Communications can be carried on wireless carriers. Examples of wireless systems include public land mobile networks (PLMN) such as cellular networks, satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). In wireless systems a communication device provides a transceiver station that can communicate with another communication device such as e.g. a base station of an access network and/or another user equipment.

According to an aspect, there is provided a method comprising; determining for a least one type of cell event, the number of occurrences of said cell event; and causing information on said number of occurrences to be sent to a base station.

The at least one cell event may comprise one or more of: inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and cell reselection in an idle mode. The method may comprise causing said information to be sent in a measurement report procedure.

The method may comprise causing said information to be sent in response to a request from said base station.

The method may comprise causing said information to be sent in a handover procedure.

The method may comprise causing said information to be sent in a reestablishment procedure. This may be after connection failure.

The method may comprise causing said information to be sent at a beginning of a connection.

The method may comprise causing said information to be sent at a beginning of a connection if a user equipment enters a eel! in an idle state.

The method may comprise causing said information to be sent at a beginning of a connection if a user equipment enters said cell in an idle state and if said cell belongs to a different base station to that of a cell in which the user equipment went into the idle state.

The method may comprise determining the number of occurrences in a given period of time.

The method may comprise receiving information defining said time period.

The above discussed method(s) may be performed by a user equipment. According to another embodiment, there is provided a user equipment configured to perform one or more of the above method steps.

According to another aspect, there is provided a method comprising; receiving information on a number of occurrences of at least one type of celt event for at least one user equipment; and using said information to determine if said user equipment should be in a dormant state.

The dormant state may be an idle state.

The at least one cell event may comprise one or more of: inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and cell reselection in an idle mode. This method may be performed in a base station.

According to another aspect, there is provided a base station which is configured to perform the previous method (s). A computer program comprising program code means adapted to perform the method(s) may also be provided. The computer program may be stored and/or otherwise embodied by means of a carrier medium.

According to another aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: determine for a least one type of cell event, the number of occurrences of said cell event; and cause information on said number of occurrences to be sent to a base station. The at least one cell event may comprise one or more of: inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and cell reselection in an idle mode.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to cause said information to be sent in a measurement report procedure.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to cause said information to be sent in response to a request from said base station.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to cause said information to be sent in a handover procedure.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to cause said information to be sent in a re- establishment procedure. This may be after connection failure.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to cause said information to be sent at a beginning of a connection.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to cause said information to be sent at a be- ginning of a connection if a user equipment enters a cell in an idle state.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to cause said information to be sent at a beginning of a connection if a user equipment enters said cell in an idle state and if said cell belongs to a different base station to that of a cell in which the user equipment went into the idle state. The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to determine the number of occurrences in a given period of time.

The at least one memory and the computer code may be configured, with the at least one processor, to cause the apparatus to receive information defining said time period.

According to another embodiment, there is provided a user equipment comprising the above apparatus.

According to another aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: receive information on a number of occurrences of at least one type of cell event for at least one user equipment; and use said information to determine if said user equipment should be in a dormant state. The dormant state may be an idle mode.

The at least one cell event may comprise one or more of: inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and cell reselection in an idle mode.

This apparatus may be provided in a base station.

According to another aspect, there is provided a base station comprising the above apparatus.

According to another aspect, there is provided an apparatus comprising; means for determining for a least one type of cell event, the number of occurrences of said cell event; and means for causing information on said number of occurrences to be sent to a base station.

The causing means may be for causing said information to be sent in a measure- ment report procedure.

The causing means may be for causing said information to be sent in response to a request from said base station.

The causing means may be for causing said information to be sent in a handover procedure. The causing means may be for causing said information to be sent in a reestab- lishment procedure. This may be after connection failure.

The causing means may be for causing said information to be sent at a beginning of a connection.

The causing means may be for causing said information to be sent at a beginning of a connection if a user equipment enters a cell in an idle state.

The causing means may be for causing said information to be sent at a beginning of a connection if a user equipment enters said cell in an idle state and if said cell belongs to a different base station to that of a cell in which the user equipment went into the idle state.

The determining means may be for determining the number of occurrences in a given period of time.

The apparatus may comprise means for receiving information defining said time period.

According to another aspect, there is provided a user equipment comprising the previous apparatus.

According to another aspect, there is provided an apparatus comprising; receiving information on a number of occurrences of at least one type of cell event for at least one user equipment; and using said information to determine if said user equipment should be in a dormant state.

The dormant state may be an idle mode.

The at least one cell event may comprise one or more of: inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and cell reselection in an idle mode. According to another aspect, there is provided a base station comprising the previous apparatus.

It should be appreciated that any feature of any aspect may be combined with any other feature of any other aspect.

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

Figure 1 shows a schematic diagram of a communication system comprising a base station and a plurality of communication devices;

Figure 2 shows a schematic diagram of a mobile communication device;

Figure 3 shows a schematic diagram of a control entity; Figure 4 shows scenarios where user equipment history information is used to evaluate the mobility status of the user equipment;

Figure 5 shows a flow of a method of an embodiment; and

Figure 6 shows schematically part of a user equipment. In the following certain exemplifying embodiments are explained with reference to a wireless or mobile communication system serving mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of a wireless communication system, access systems thereof, and mobile communication devices are briefly explained with reference to Figures 1 to 3 to assist in understanding the technology underlying the described examples.

An example of wireless communication systems are architectures standardized by the 3rd Generation Partnership Project (3GPP). A latest 3GPP based development is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The various development stages of the 3GPP LTE specifications are referred to as releases. More recent developments of the LTE are often referred to as LTE Advanced (LTE-A). The LTE employs a mobile architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Base stations of such systems are known as evolved or enhanced Node Bs (eNBs) and may provide E-UTRAN features such as user plane Radio Link Control/Medium Access Control/Physical layer protocol (RLC/MAC/PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other examples of radio access system include those provided by base stations of systems that are based on technologies such as wireless local area network (WLAN) and/or WiMax (Worldwide Interoperability for Microwave Access). A device capable of wireless communications can communicate via at least one base station or similar wireless transmitter and/or receiver node. In figure 1 a base station 10 is shown to be serving various mobile devices 20 and a machine-like terminal 22. Base stations are typically controlled by at least one appropriate controller apparatus so as to enable operation thereof and management of mobile communication devices in commu- nication with the base stations. The base station can be connected further to a broader communications system 12. It shall be understood that a number of neighbouring and/or overlapping access systems or radio service areas provided by a number of base stations may exist. A base station site can provide one or more cells or sectors, each sector providing a cell or a subarea of a cell. A possible mobile communication device for transmitting in uplink and receiving in downlink will now be described in more detail with reference to Figure 2 showing a schematic, partially sectioned view of a communication device 20. Such a communication device is often referred to as user equipment (UE) or terminal. An appropriate communica- tion device may be provided by any device capable of sending radio signals to and/or receiving radio signals. Non-limiting examples include a mobile station (MS) such as a mobile phone or what is known as a 'smart phone', a portable computer provided with a wireless interface card or other wireless interface facility, personal data assistant (PDA) provided with wireless communication capabilities, or any combinations of these or the like. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, and multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communication or multimedia services or simply an access to a data commu- nications network system, such as the Internet. Non-limiting examples of content data include downloads, television and radio programs, videos, advertisements, various alerts and other information.

The device 20 is configured to receive signals in the downlink 29 over an air interface via appropriate apparatus for receiving and to transmit signals in the uplink 28 via appropriate apparatus for transmitting radio signals. In Figure 2 the transceiver apparatus is designated schematically by block 26. The transceiver apparatus 26 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

The device is also provided with at least one data processing entity 21 , at least one memory 22 and other possible components 23 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with base stations and/or other communication devices. The data processing, storage and other relevant apparatus can be provided on an appropriate circuit board and/or in chipsets. This apparatus is denoted by reference 24. The user may control the operation of the device by means of a suitable user interface such as key pad 25, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 27, a speaker and a microphone can be also provided. Furthermore, a communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto. Figure 3 shows an example of a control apparatus 30 for a communication system. The control apparatus may be part of, coupled to and/or for controlling a base station. In some embodiments a base station may comprise an integrated control apparatus and some other embodiments the control apparatus can be provided by a separate network element. The control apparatus can be interconnected with other control entities. The control apparatus and functions may be distributed between a plurality of control units. In some embodiments each base station can comprise a control apparatus, in alternative embodiments, two or more base stations may share a control apparatus. The arrangement of the control depends on the standard, and for example in accordance with the cur- rent LTE specifications no separate radio network controller is provided. Regardless of the location, the control apparatus 30 can be understood as providing control on communications in the service area of at least one base station.

The control apparatus 30 can comprise at least one memory 31 , at least one data processing unit 32, 33 and an input/output interface 34. Via the interface the control ap- paratus can be coupled to a base station to cause operation of the base station in accordance with the below described embodiments. The control apparatus can be configured to execute an appropriate software code to provide the control functions.

It has been proposed to look for LTE RAN (radio access network) enhancements for diverse data applications. In order to provide always on connectivity, mechanisms are identified and specified at the RAN level to enhance the ability of LTE to handle diverse traffic profiles. With such traffic loads, the identified mechanisms may permit better trade-offs to be achieved when balancing the needs of network efficiency, UE battery life, signalling overheads, user experience and/or system performance.

In some embodiments user equipment applications are known where traffic traces, i.e. data traffic or packets captured from live systems or apparatus running one or more applications of interest, are captured from networks and analysed. It should be appreciated that the user equipment applications may have very different characteristics. Background and instant messaging IM traffic scenarios require a relatively high signalling overhead to keep the applications always on. Background traffic refers to the traffic from an unattended phone with applications not in an "active phase" (i.e. not including email retrieval, no IM sending etc .). A large number of applications may generate such background traffic e.g. Skype, Facebook, Gtalk etc. IM traffic includes IM background traffic, for example by Mobile QQ, MSN etc.

Background data may be characterised by long periods, perhaps several minutes, of inactivity followed by relatively short bursts, for example a few seconds, of activity. Signalling load has been proposed as a metric for diverse data. Signalling load has been compared and four schemes have been proposed for handling inactive periods during background traffic. One mode is a fully connected-DRX (discontinuous reception) mode, a second mode is a network-based dormancy timer, a third mode is UE initiated dormancy and the fourth mode is mobility based network initiated dormancy.

In mobility-based network initiated dormancy, the mobility status of user equipment may be taken into consideration. There is an information element IE called the 'UE history information'. This information element is propagated via the X2AP handover request message and the S1AP handover request message. This information element is used by the base station to evaluate the mobility of the user equipment.

This information element contains information of up to N cells that a user equipment has been served by in the active state prior to the target cell. N may be 16. This information element can include cell type information and time the user equipment stayed in the cell. The cell type may be very small, small, medium, large or the like. Other cell types may be used. In some proposals, the maximum time maybe 4095 seconds. However, in other embodiments this may be different.

This information may be used in subsequent handover preparations by means of the handover preparation procedures over the S1 and X2 interfaces. The X2 interface is the interface between two base stations. The S1-U interface is between the base station and a serving gateway for the per bearer user plane tunneling and inter base station path switching during handover. The S1-MME interface is the reference point for the control plane protocol between E-UTRAN and MME (mobility management entity).

The interfaces provide the target base station with a list of previously visited cells and associated (on a per cell basis) information elements. The handover preparation procedures may also trigger the target base station to start collecting and storing user equipment history information and thus to propagate the collected information.

The information element relating to the user equipment history information may be used to evaluate user equipment mobility status by the base station. Reference is made by way of example to figure 4 which shows some issues which may arise when the user equipment history information IE is used to evaluate user equipment mobility status.

The parameter of time that the user equipment stayed in the cell may only record the time when the user equipment is an active state. However, the user equipment may switch between the active and idle states many times when it stays in one cell. Accordingly, the parameter of time that a user equipment stays in the cell may not reflect the total time that a user equipment stays in one cell. In figure 4, the time that a UE in a cell is in the active state is referenced in the solid line marked A and the time that the user equipment is in the idle state is shown in dotted lines and referenced I.

The user equipment history information IE may be propagated by the handover preparation procedure. If the user equipment bypasses one or several cells in the idle state and sets up a radio resource control RRC connection to a new base station, the information element may not be delivered to the new cell and may therefore be lost. As shown in figure 4, when the user equipment passes from the first cell, cell 1 , to the second cell, cell 2, the user equipment history information IE will be propagated to the target cell, that is cell 2. This is because the UE is an active mode as it is handed over from cell 1 to cell 2. However, when the user equipment passes from ceil 2 to cell 3, the user equipment is in the idle mode and the new equipment history information IE will be lost when the user equipment returns back to the active state when in cell 3.

The user equipment history information may only record at maximum 16 cells that a user equipment has been served by in an active state prior to the target cell. This means that the base station may only have the information about at most 15 consecutive previous handovers. This may only be of relatively limited use in order to get a suitable estimation of the user equipment mobility.

If mobility-based network initiated dormancy is used, the inter base station hand over frequency may be of more value to the base station to determine when the user equipment needs to go into the dormancy state, considering its relatively higher cost compared to intra base station handover. However, as discussed previously, a deviation may occur if only the time that user equipment stays in a cell, the number of last visited cells and the cell type used to evaluate the handover frequency by the base station. User equipment may classify itself into one of three mobility classes, normal, medium and high. The UE may classify itself by counting the number of cell reselections in the idle mode and the number of handovers in the connected mode during one predefined time duration.

If the base station uses the IE and the user equipment uses the count values, it is clear that the base station and the UE are using two different sets of information to evaluate the handover frequency and/or the user equipment mobility status.

The UE may count all cell changes (including both reselections and handovers) for the mobility state estimation procedure and the UE may provide its current mobility state and the cell change count to the base stations. The messages may be RRCConnection- SetupComplete and RRCConnectionReconfigurationComplete.

UEMobiIityStatelnformation::= SEQUENCE {

5 ueMobilityState NUMERATED {normal, medium, high, sparel}, cellChangeCount INTEGER (0..255),

}

UEMobilityStatelnformation field descriptions ueMobilityState indicates the current UE mobility state (normal, medium, or high). CellChangeCount

Indicates the amount of cell changes (cell reselections and handovers

bined) that have taken place within the t-Evaluation time period

The base station can perform finer mobile state estimation based on the reported

UE's mobility state and counters of cell changes. If mobility based network initiated dormancy is used, the inter-base station HO frequency costs more to base station to determine when to send the UEs to dormancy. Currently no differentiation is made between the inter base station handover from intra base station HO. In case of RRC Connection (Re-) establishment after Radio Link Failure (RLF) or

Handover Failure (HOF) to a non-source cell (i.e. a source cell is a cell on which the UE is camping immediately before connection failure), the UE will perform the cell selection procedure, which currently is not counted towards either the number of handover or the number of cell reselections. In some embodiments, the user equipment is configured to report the available counters to a base station to help the base station to evaluate the mobility status and/or handover frequency of the user equipment. Some embodiments may use one or more of the following information: Number of successful inter base station cell selection. Inter base station cell selection is the successful (re-)establishment of a connection to a non-source inter-eNB ceil after connection failure has occurred. Connection failure may be one or more of RLF (radio link failure) and HOF (hand over failure). This may or may not involve a cell change. The number of intra base station cell selections after connection failure may be reported. Intra base station cell selection is the successful (re-) establishment of a connection to a non-source intra-eNB cell after connection failure has occurred. Some embodiments may use inter base station cell selections only. Some embodiments may use inter and intra base station cell selections. Number of inter base station handovers may be reported.

Number of intra-base station handovers may be reported. Some embodiments may use inter base station handovers only. Some embodiments may use inter and intra base station handovers.

Number of cell reselections in the idle mode in one predefined time duration. The parameters may be measured by counters or the like.

The counters may be accumulated within a predetermined time duration. The predefined time duration may be configured by the base station via the broadcast channel. In some embodiments an existing time duration may be reused. For example, T_CR ax iTiay be used. This currently specifies the duration for evaluating allowed amount of cell rese- lections

The information may be reported to the base station in one or more of the following cases.

At the beginning of a connection, if the user equipment enters the cell in an idle state, for example with the RRC connection setup complete. The information may only be reported at the beginning of the connection if the idle user equipment enters a cell be^¬ longing to a different base station from the cell in which the user equipment goes into the idle state last time. For example if the user equipment goes into the idle state in cell 1 and then goes active in cell 2 of the same base station, then the user equipment does not report anything to the first base station. However, if the user equipment goes active in cell 2 of a second base station, then the user equipment will report the counters to the second base station. During the handover procedure, the information may be reported if the user equipment is handed over to the cell, that is if the RRC connection reconfiguration is complete.

The information may be reported if the user equipment successfully (re-)establish to a non-source cell, that is if the RRC connection reestablishment procedure is complete. The information may be provided on request from the base station by example detecting an indication from the base station asking for this information. An existing user equipment information request/response procedure may be used in this context or a new procedure may alternatively or additionally be used.

The information may be provided during the measurement report procedure, for example during the RRC measurement report procedure.

In some embodiments, the counters reported by the user equipment are propagated to the target base station on the S1/X2 to interface in for example handover request messages or the like.

The user equipment history information IE may be modified to record the handover type, for example if the handover is via the X2 interface or via the S1 interface.

Reference is now made to figure 6 which schematically shows part of the user equipment. The user equipment has a first counter 100 which counts the number of successful inter base station cell selections in a given time. A second count of 02 counts the number of successful intra base station cell selections in the given time. A third counter 104 counts the number of cell re-selections in the time. A fourth counter 1 0 counts the number of inter base station handovers in the time. The fifth counter 112 counts the number of intra base station handovers in a time. A timer control 106 is provided which controls each of the counters. This will ensure that the values which are in the current period are retained and earlier values which fall outside the given period are discarded or no longer counted. A message generator 108 is configured to report information from one or more of these counters to the base station. The message generator 108 may be configured to generate a message in the situations previously discussed.

It should be appreciated that the part of the user equipment shown in figure 6 may be implemented in hardware and/or software. It should be appreciated that one or more of the counters shown in figure 6 may be omitted.

Reference is made to figure 5 which shows a method. In step S1 , the inter base station cell selections are counted. In step S2, the intra base station cell selections are counted.

In step S3, the number of cell reselections in the idle mode are counted.

In step S4, the number of inter base station handovers are counted.

In step S5, the number of intra base station handovers are counted. It should be appreciated that steps S1 to S5 will run generally in parallel. Whenever there is an event which is being counted, that event will be counted.

A message generation event occurs in step S6. The message generation event may be one or more of the following: at the beginning of a connection; the user equipment enters the cell in the idle state; during a handover procedure; successfully re-establishment to a non-source cell; in response to a request from a base station; and/or during a measurement report procedure. These are as discussed in more detail previously.

In response to the message generation event, a message is sent with the count information to the base station instep S7. That message may include the count information with one or more of the five count values.

In step S8, the count information is used at the base station to determine if network initiated dormancy should be used. This dormancy may be mobility based network initiated dormancy.

It should be appreciated that in some embodiments, one or more of the count steps may be omitted.

The message was sent to the base station may include other information. Alternatively, user equipment may send, from time to time, other information which is used at the base station in order to determine the mobility-based network initiated dormancy.

When a session is established and a data call is active, the radio link can be released after a set period of inactivity, but the state of the session will be preserved. When data is sent to or from the device, the radio link will be re-established and the session will resume. This is an example of dormancy.

A base station may provide configuration to a user equipment. This configuration may comprise one or more of time period for the user equipment counters, one or more events to trigger reporting and one or more messages to trigger reporting. It is noted that whilst embodiments have been described in relation to LTE, similar principles can be applied to any other communication system or to further developments with LTE. Therefore, although certain embodiments were described above by way of example with reference to certain exemplifying architectures for wireless networks, tech- nologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

The required data processing apparatus and functions of a base station apparatus, a communication device and any other appropriate apparatus may be provided by means of one or more data processors. The described functions at each end may be provided by separate processors or by an integrated processor. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non limiting examples. The data processing may be distributed across several data processing modules. A data processor may be provided by means of, for example, at least one chip. Appropriate memory capacity can also be provided in the relevant devices. The memory or memories may be of any 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.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some embodiments may be implemented in hardware, while other aspects may be implemented in firmware or soft- ware which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, 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. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of some embodiments. However, various modifica- tions and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fail within the scope of this invention as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more of any of the other embodiments previously discussed.

Claims

What is claimed is:

1. A method comprising;

determining for a least one type of cell event, the number of occurrences of said cell event; and

causing information on said number of occurrences to be sent to a base station.

2. A method as claimed in claim 1 , wherein said at least one cell event comprises one or more of:

inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and cell reselection in an idle mode.

3. A method as claimed in any preceding claim, comprising causing said information to be sent in at least one of a measurement report procedure and a handover procedure.

4. A method as claimed in any preceding claim, comprising causing said information to be sent in response to a request from said base station. 5. A method as claimed in any preceding claim, comprising causing said information to be sent in an establishment or re-establishment procedure.

6. A method as claimed in any preceding claim, comprising causing said information to be sent at a beginning of a connection.

7. A method as claimed in claim 6, comprising causing said information to be sent at a beginning of a connection if a user equipment enters a cell in an idle state.

8. A method as claimed in any preceding claim, comprising determining the number of occurrences in a given period of time.

9. A method as claimed in any preceding claim, comprising receiving information defining said time period.

10. A method comprising; receiving information on a number of occurrences of at least one type of cell event for at least one user equipment; and using said information to determine if said user equipment should be in a dormant state.

11. A method as claimed in claim 10, wherein said dormant state comprises an idle state. 2. A method as claimed in claim 10 or 1 1 , wherein said at least one cell event comprises one or more of: inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and cell reselection in an idle mode.

13. A computer program comprising computer executable instructions which when run cause the method of any one of the preceding claims to be performed.

14. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: determine for a least one type of cell event, the number of occurrences of said cell event; and cause information on said number of occurrences to be sent to a base station.

15. An apparatus as claimed in claim 14, wherein the at least one cell event comprises one or more of: inter base station cell selection; intra base station cell selection; inter base station handover; intra base station handover; and eel! reselection in an idle mode.

16. An apparatus as claimed in claim 14 or 15, wherein the at least one memory and the computer code are configured, with the at least one processor, to cause the apparatus to cause at least one of:

said information to be sent in a measurement report procedure; said information to be sent in response to a request from said base station;

said information to be sent in a handover procedure;

said information to be sent in a reestablishment procedure; and

said information to be sent at a beginning of a connection.

17. An apparatus as claimed in claim 6, wherein the at Ieast one memory and the computer code are configured, with the at Ieast one processor, to cause the apparatus to cause said information to be sent at a beginning of a connection if a user equipment enters a cell in an idle state. 8. An apparatus as claimed in any of claims 14 to 7, wherein the at least one memory and the computer code are configured, with the at least one processor, to cause the apparatus to determine the number of occurrences in a given period of time. 19. An apparatus as claimed in claim 18, comprising a receiver configured to receive information defining said time period.

20. A user equipment comprising an apparatus as claimed in any of claims 14 to 19. 21. An apparatus comprising at Ieast one processor and at Ieast one memory including computer code for one or more programs, the at Ieast one memory and the computer code configured, with the at ieast one processor, to cause the apparatus at Ieast to: receive information on a number of occurrences of at Ieast one type of cell event for at Ieast one user equipment; and use said information to determine if said user equipment should be in a dormant state.

22. An apparatus as claimed in claim 21 , wherein said dormant state com- prises an idle mode.

23. A base station comprising an apparatus as claimed in claims 21 or 22.