GB2501931A

GB2501931A - Wireless devices and apparatus and computer programs therefor

Info

Publication number: GB2501931A
Application number: GB1208281.4A
Authority: GB
Inventors: James Howard Tooley; Brian Alexander Martin
Original assignee: Renesas Mobile Corp
Current assignee: Renesas Electronics Corp
Priority date: 2012-05-11
Filing date: 2012-05-11
Publication date: 2013-11-13
Also published as: GB201208281D0

Abstract

A wireless device (10) determines that it would. like to transition from a non-idle state to an idle state. In one embodiment, the wireless device (10) determines whether it has received. an indication (15) from a base station (11) that the base station (11) enables transition of the wireless device (10) to the idle state. The wireless device (10) sends a transition request (17) to request an instruction to transition to the idle state only if the wireless device (10) has received an 'indication (15) that the base station (11) enables transition of the wireless device (10) to the idle state_ In another embodiment. the wireless device (10) sends a transit ion request to request an 'instruction to transition to the idle state unless the wireless device (10) has received an indication that the base station (11) does not enable transition of the wireless device (10) to the idle state. The transition request may be a fast dormancy request.

Description

WIRELESS DEVICES AND APPARATUS

AND COMPUTER PROGRAMS THEREFOR

Technical Field

S The present invention relates to a method of operating a wireless device, apparatus for a wireless device, a method of operating a base station, apparatus for a base station, and computer programs therefor.

Background

Thc following abbreviations arc uscd in the prcscnt specification: 3GPP Third Generation Partnership Project DRX discontinuous reception eNB evolved Node B FD Fast Dormancy LTE Long Term Evolution PS packet switched RF radio frequency RNC radio network controller RRC Radio Resource Control

SCRI SIGNALLING CONNECTION RELEASE INDICATION

SI system information UE user equipment IJMTS Universal Mobile Telecommunications System URA user registration area IJTRAN Universal Terrestrial Radio Access Network Wireless networks have in recent years experienced a considerable increase in the amount of data being transmitted to and from wirelessly connected devices or "user equipment" (UE). The traffic characteristics of this data traffic are very different from that of traditional mobile phones, and can be characterised by its use of a lot of background signalling and bursty traffic consisting of relatively small data packets. The introduction of machine-type communications to the networks can also be expected to follow this trend. As a result, wireless networks need to implement new mechanisms to cope with this new traffic and make efficient use of the available S resources while providing high capacity and throughputs and minimum delays. Of particular concern in improving the support of this low volume, bursty data is minimising the signalling load on the network and improving the power consumption of the user equipment.

In general, in many types of wireless systems, the user cquipmcnt is typically in one of a number of predefined activity states. These may be for example an idle state, a paging state in which the user equipment checks a paging channel for incoming paging messages at prcdcfined time intervals and has an RRC (Radio Resource Control) connection, and one or more data connection states in which the user equipment can actively transmit and receive data. In general, these states use increasingly more power at the user equipment and also more network signalling. In order to minimise power consumption, particularly to maximise battery life before recharging is required, the user equipment is often caused to operate in a state having a low or the lowest power consumption possible, depending on for example the operational demands of the user equipment and/or network requirements. A particular concern from the perspective of the wireless network operator is to keep down the amount of control signals that have to be passed to and from the user equipment in order to cause the user equipment to transition between states, and/or to allow the user equipment to send or receive data, and/or to locate the user equipment.

As a particular example, Fast Dormancy (FD) is a 3GPP (Third Generation Partnership Project) feature specified from Release 8 which allows the UE to request that the network reconfigure the UE into a more power efficient state by the UE indicating that packet data transfer has ended. This feature allows the UE to optimise the power consumption particularly during bursty packet data transfer, which is a typical characteristic of the data activity of smart phones. To initiate Fast Dormancy, the UE sends a SIGNALLING CONNECTION RELEASE INDICATION (SCM) message to the network. This message triggers the network to send a signal to the TIE to cause the UE to move into a more power efficient state, which effectively provides the network with control over this procedure. However, there are situations where the S network does not enable moving the user equipment to a (particular) low power state, and in such cases the sending of the requests by the UE to be moved to the low power state will be pointless and wasteful. The sending of such requests in itself consumes power, as well as adding to the control signals being sent across the network.

Summary

According to a first aspect of the present invention, there is provided a method of operating a wireless device, the method comprising: the wireless device being in a data transfer state in order to be capable of engaging in data transfer with a base station; and the wireless device transitioning from the data transfer state to a paging channel state on completion of data transfer with a said base station; the wireless device transitioning from the paging channel state to an idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.

In an cmbodimcnt, to transition to the idle state, the wireless device is required to send a transition request to a said base station and to receive an instruction in response thereto to instruct the wireless device to transition to the idle state, the wireless device being arranged to send a said transition request only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.

In an embodiment, the transition request is a Fast Dormancy request. This may be sent in the form of a signalling connection release indication (SCM) for example. As an alternative, this transition request may be sent in a "Cell Update" or a "UIRA (user registration area) Update" message.

In an embodiment, the method comprises: the wireless device receiving an indication from a said base station as to whether or not said base station enables transition of the wireless device to the idle S state; the wireless device determining that it would like to transition to an idle state; and, if the received indication from said base station indicates that said base station cnables transition of the wireless device to thc idle state, the wireless dcvice sending a said transition request to said base station.

In an embodiment, the indication from a said base station is received as at least one of a system information message, as part of a radio resource configuration message, and via a cell/user registration area update confirm message.

In an embodiment, the data transfer state is a Universal Mobile Telecommunications System (UMTS) CELL FACH state or CELL DCH state, the paging channel state is a IJMTS CELL PCH or URA PCH state, and the idle state is a UIMTS Idle Mode state.

According to a second aspect of the present invention, there is provided a method of operating a wireless device, the method comprising: the wireless device determining that it would like to transition from a non-idle state to an idle state; the wireless device determining whether it has received an indication from a said base station that said base station enables transition of the wireless device to the idle state; and the wireless device sending a transition request to a said base station to request an instruction to transition to the idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.

In an embodiment, the method comprises: the wireless device receiving an indication from a said base station that said base station enables transition of the wireless device to the idle state; and S the wireless device sending a said transition request to said base station.

In an embodiment, the indication from a said base station is received as at least one of a system information message, as part of a radio resource configuration mcssagc, and via a cclL'uscr rcgistration area updatc confirm messagc.

In an embodiment, the transition request is a Fast Dormancy request.

In an embodiment, the non-idle state is a UMTS CELL PCH or URAPCH state, and the idk state is a TJMTS Tdle Mode state.

According to a third aspect of the present invention, there is provided apparatus comprising a processing system for a wireless device that is operable in an idle state and at least one non-idle state, the processing system being constructed and arranged to: determine whether a said wireless device has received an indication from a base station that said base station enables transition of thc wireless device to the idle state; and cause the wireless device to send a transition request to a said base station to request an instruction to transition from a non-idle state to the idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.

There may be provided a wireless device comprising apparatus as described above.

According to a fourth aspect of the present invention, there is provided a computer program for a wireless device, the computer program comprising instructions such that when the computer program is executed on a processing system of the wireless device, the wireless device is arranged to: S determine that it would like to transition from a non-idle state to an idle state; determine whether it has received an indication from a said base station that said base station enables transition of the wireless device to the idle state; and send a transition request to a said basc station to request an instruction to transition to the idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.

According to a flflh aspect of the present invention, there is provided a method of operating a cellular network base station, the method comprising: if the base station enables transition of a wireless device serviced by the base station from a non-idle state to an idle state, the base station transmitting an indication that the base station enables transition of a wireless device serviced by the base station from the non-idle state to the idle state.

In an embodiment, the method comprises transmitting the indication as at least one of a system information message, as part of a radio resource configuration message, and via a cell!user registration area update confirm message.

According to a sixth aspect of the present invention, there is provided apparatus comprising a processing system for a cellular network base station, the processing system being constructed and arranged to: cause the base station to transmit an indication that the base station enables transition of a wireless device serviced by the base station from a non-idle state to an idle state if the base station enables transition of a wireless device serviced by the base station to the idle state from the non-idle state.

There may be provided a cellular network base station comprising apparatus as described above.

According to a seventh aspect of the present invention, there is provided a S computer program for a cellular network base station, the computer program comprising instructions such that when the computer program is executed on a processing system of the base station, the base station is arranged to: transmit an indication that the base station enables transition of a wireless dcvicc serviced by thc base station from a non-idlc statc to an idle statc if thc basc station enabics transition of a wirclcss dcvicc scrviccd by the base station to the idle state from the non-idle state.

According to an eighth aspect of the present invention, there is provided a method of operating a wireless device, the method comprising: the wireless device determining that ft would like to transition from a non-idle state to an idle state; and the wireless device sending a transition request to a said base station to request an instruction to transition to the idle state unless the wireless device has received an indication from a said base station that said base station does not enable transition of the wireless device to the idle state.

According to a ninth aspect of the present invention, there is provided apparatus comprising a processing system for a wireless device that is operable in an idle state and at least one non-idle state, the processing system being constructed and arranged to: determine that it would like the wireless device to transition from a non-idle state to an idle state; and cause the wireless device to send a transition request to a said base station to request an instruction to transition to the idle state unless the wireless device has received an indication from a said base station that said base station does not enable transition of the wireless device to the idle state.

S

According to a tenth aspect of the present invention, there is provided a computer program for a wireless device, the computer program comprising instructions such that when the computer program is executed on a processing system of the wireless device, the wireless device is arranged to: determine that it would like to transition from a non-idle state to an idle state; and send a transition request to a said base station to request an instruction to transition to the idle state unless the wireless device has received an indication from a said base station that said base station does not enable transition of the wireless device to the idle state.

According to an eleventh aspect of the present invention, there is provided a method of operating a cellular network base station, the method comprising: if the base station does not enable transition of a wireless device serviced by the base station from a non-idle state to an idle state, the base station transmitting an indication that the base station does not enable transition of a wireless device serviced by the base station from the non-idle state to the idle state.

According to a twelfth aspect of the present invention, there is provided apparatus comprising a processing system for a cellular network base station, the processing system being constructed and arranged to: cause the base station to transmit an indication that the base station does not enable transition of a wireless device serviced by the base station from the non-idle state to the idle state if the base station does not enable transition of a wireless device serviced by the base station from a non-idle state to an idle state.

According to a thirteenth aspect of the present invention, there is provided a computer program for a cellular network base station, the computer program comprising instructions such that when the computer program is executed on a processing system of the base station, the base station is arranged to: transmit an indication that the base station does not enable transition of a wireless device serviced by the base station from the non-idle state to the idle state if the base station does not enable transition of a wireless device serviced by the base station from a non-idle state to an idle state.

S

There may be provided a non-transitory computer-readable storage medium comprising a set of computer-readable instructions stored thereon, which, when executed by a processing system, cause the processing system to carry out a method as dcscribcd above.

The processing systems described above may comprise at least one processor and at least one memory including computer program instructions, the at least one memory and the computer program instructions being configured to, with the at least one processor, cause the apparatus at least to perform as described above.

In certain examples of embodiments of the present invention, a base station sends indications that it enables transitions by wireless devices serviced by the base station to an idle state, and can therefore send an instruction to cause a wireless device to transition to the idle state. In certain examples of embodiments of the present invention, a wireless device only sends a transition request to a base station to request an instruction to transition to the idle state if it "knows" that thc base station enables such transitions, i.e. the base station can respond with an instruction to the wireless device to transition to the idle state. This keeps down unnecessary sending of control signals or messages across the network, and can also contribute to conserving power at the wireless device, and therefore conserves battery life in the case of battery-powered wireless devices. This may be achieved in certain examples of embodiments of the present invention by the wireless device only sending such a transition request if it has received a positive indication that the base station enables such transitions, i.e. the wireless device will not send such a transition request if it has received an indication that the base station does not support such transitions (i.e. this feature is not enabled for the networklbase station) or indeed has not received any indication at all (whether positive or negative). In other embodiments of the present invention, the base station sends indications that it does not enaNe transitions by wireless devices serviced by the base station to an idle state. In embodiments of the present invention, wireless devices do not send a transition request to a base station to request an S instruction to transition to the idle state if it "knows" that the base station does not enable such requests. This again saves unnecessary sending of control signals or messages across the network, and can also conserve power at the wireless device, and therefore conserves battery life in the case of battery-powered wireless devices.

Further features and advantages of the invention will bccomc apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 shows schematically a wireless device operating in a cellular network serviced by a base station; Figure 2 shows a schematic message sequence diagram relating to an example of an embodiment of the present invention; and Figurc 3 shows a schematic message sequence diagram relating to anothcr example of an embodiment of the present invention.

Detailed Description

"Wireless devices" include in general any device capable of connecting wirelessly to a network, and includes in particular mobile devices including mobile or cell phones (including so-called "smart phones"), personal digital assistants, pagers, tablet and laptop computers, content-consumption or generation devices (for music and/or video for example), data cards, USB dongles, etc., as well as fixed or more static devices, such as personal computers, game consoles and other generally static entertathment devices, various other domestic and non-domestic machines and devices, etc. The term "user equipment" or UE is often used to refer to wireless devices in general, and particularly mobile wireless devices.

Figure 1 shows schematically a user equipment or wireless device, in this case S in the form of a mobile phone!smartphone 1. The user equipment 1 contains the necessary radio module 2, processor(s) and memory/memories 3, antenna 4, etc. to enable wireless communication with the network. The user equipment 1 rn use is in communication with a radio mast 5. As a particular example in the context of UMTS (Universal Mobile Telecommunications System), there may be a network control apparatus 6 (which may be constituted by for example a so-called Radio Network Controller) operating in conjunction with one or more Node Bs (which, in many respects, can be regarded as "base stations"). As another example, LTE (Long Term Evolution) makes use of a so-called evolved Node B (eNB) where the RF transceiver and resource management/control functions are combined into a single entity. The term "base station" is used in this specification to include a "traditional" base station, a Node B, an evolved Node B (eN B), or any other access point to a network, unless the context requires otherwise. The network control apparatus 6 (of whatever type) may have ifs own processor(s) 7 and memory/memories 8, etc. Moreover for convenience and by convention, the terms "network", "network control apparatus" and "base station" will often be used interchangeably, depending on the context.

The following specific examples of embodiments of the present invention are given particularly in the context of 3GPP (Third Generation Partnership Project) UMTS (Universal Mobile Telecommunications System) systems. However, the principles of the present invention are applicable to other wireless systems, operating according to different standards and protocols.

The system currently in use in 3GPP provides for a number of defined activity states for the user equipment, including an Idle state, a CELL PCHIURA PCH (paging channel) state, a CELL_FACH (forward access channel) state, and a CELL_DCH (dedicated channel) state. In the Idle state, the user equipment does not have an RRC (Radio Resource Control) connection and this is the state having the lowest power consumption. In the CELL PCH/TJRA PCH state, the user equipment is again in a low power consumption state as it only periodically looks for incoming paging messages, and in this state does have a RRC connection. However, the user S equipment needs to be in the CELL FACH or CELL_DCH state in order to be able to perform both transmission and reception of data (including in particular "user" data, as opposed to data relating to control or management of the device and its network connection, etc. for example). In the CELL_DCH state, a dedicated physical channel is allocated to the user equipment. In the CELL FACH state, the user equipment shares the physical channel with other user equipment, though nevertheless may have a dedicated logical channel. As is well understood, a logical channel in this context is an information stream dedicated to the transfer of a specific type of information over the radio interface and corresponds to an individual signal which can be separated or isolated from an aggregate of signals which occupy the same physical bandwidth or channel. CELL FACH can be regarded as a transition state between the CELL_PCH/IJRA_PCH and CELL_DCH states. Keeping the user equipment in CELL FACH state improves power consumption for the user equipment compared to the CELL DCH state (because the transmitter and/or receiver may be switched off for longer periods of time while no uplink data is available and during discontinuous reception or "DRX") and also reduces the network signalling load (by avoiding radio resource control or "RRC" signalling to perform a state transition from the PCH or Idle states to the CELL_FACH state when both data transmission and reception are required). Nevertheless, the CELL_FACH state still has a higher power consumption for the user equipment than the PCH or Idle states.

The 3GPP standards allow the UE to trigger so-called Fast Dormancy by sending the SIGNALLING CONNECTION RELEASE INDICATION (SCRI) in all connected states, including CELL_PCFI, URA PCI-I, CELL FACI-1 and CELL DCH.

In particular, if there is no more packet switched data that needs to be sent by the UE and after a timer ("Timer T323") has expired, the UE in one of the connected states can send the SCRI message with an information element (IE) "Signaling Connection Release Indication Cause" (SCRI with Cause) to the network/base station. As an alternative, this transition request may be sent in a "Cefl Update" or a "URA Update" message. In any event, after the transition request message is received, the network may initiate a state transition, i.e. exchange control signals with the UE, to move the S UE to Idle Mode, CELL PCH, URA PCH or CELL FACH state to achieve lower power usage at the UE and reduced network signalling.

The UE may trigger Fast Dormancy when in one of the paging channel states, i.c. the CELL PCH state or the URA PCH state, as it wants the network to move it to the Idle Mode state to achieve maximum power savings and therefore typically longer battery life in the case of a mobile device. In the case that the DRX cycle length in CELL_PCH or URA_PCH as the case may be is equal to or longer than the DRX cycle length in Idle Mode, then the UE is limited to sending the SCRI only once.

However if the DRX cycle in CELL_PCH or URA PCH as the case may be is shorter than the DRX cycle length in Idle Mode, then the UE can send the SCRI as many times as it wants. The same issue may apply for other transition requests sent by the UE, including for example if the transition request is sent in a "Cell Update" or a "TIRA Update" message.

A problem with this behaviour is that certain network implementations do not enable transitioning the UE to Idle Mode for Fast Dormancy. This means that the UE will potentially send the transition request message unnecessarily, and indeed may send the transition request messages multiple times unnecessarily, as the network will not move the UE to Idle Mode state regardless. This problem is exacerbated by the fact that in order to be able to send the transition request message when in the CELL PCH or URA PCH state, the UE must first move to the FACH or DCFI state and so must perform a Cell Update procedure. This itself requires muhiple signals to be exchanged between the UE and the network, with the UE moving into a high power consumption state but with no benefit as the UE will only be returned back to the CELL_PCH or URA PCH state and not Idle Mode as it desires.

In examples of embodiments of the present invention, the network signals to the UE whether the network enables Fast Dormancy transitions to the Idle Mode state (i.e. the feature of Fast Dormancy transitions to the Idle Mode state is enabled for the network), which is not an RRC connected state. By receiving signalling from the S network that indicates whether the network will transition the UE to the Idle Mode state in response to receipt of a transition request message (i.e. a request by the tilE to be moved to the Idle Mode state), the UE can decide whether or not to send the a transition request message when in the CELL_PCH or URA_PCH state in the first place. If the network signals that it does not support Fast Dormancy transition to Idle Mode, then the UE is arranged not to send a transition request message when in the CELL PCH or URA PCH state as it know that the network will not move the UE to a more power efficient state. This can save the UE unnecessarily sending transition request messages and transitioning to connected states that have a higher power consumption, which saves power and keeps down the network traffic of control signals passing back and forth. On the other hand, if the network signals that it does support Fast Dormancy transition to Idle Mode, then the UF can send the transition request message when in the CELL PCH or URA PCH state to trigger the network to move it to the Idle Mode state as desired and determined by the UE. A number of different arrangements for the network to signal to the UE whether the network supports Fast Dormancy transitions to the Idle Mode state are discussed in detail below.

Figure 2 shows a schematic message sequence diagram relating to an example of an embodiment of the present invention. A UE 10 and the network 11 (i.e. the base station, Node B, evolved Node B (eNB), network control apparatus, etc., including as a particular example a UTRAN (Universal Terrestrial Radio Access Network)) exchange data and messages. In sequence moving down the diagram shown in Figure 2, the UF 10 and network H transfer packet data 12, for example if the user of the UE is browsing the World Wide Web using the Internet, receiving or sending emails, etc., or if applications running in the background on the UE 10 are sending or receiving data, such as occasionally checking with a central mail server whether an email for the user has been received, etc. When sending or receiving data, the UE has to be in a connected state that permits data transfer, such as the CELL FACH state or CELL DCH state in the case of a 3GPP UMTS network. Once the current packet data transfer 12 has ended, the UE 10 can request the network 11 to move the tiE 10 S to a lower power consumption state, such as the CELL PCH or URA PCH state in the case of a 3GPP UMTS network. As is known in the case of a 3GPP UMTS network, this can be achieved by the UE 10 sending a RRC SIGNALLING CONNECTION RELEASE INDICATION (SCRI) 13 that includes the cause value lIE Requested PS Data session end". As an alternative, this transition request may be sent in a "Cell Update" or a "URA (user registration area) Update" message. In any event, as a result of receipt by the network 11 of this transition request message 13, the network 11 and tiE 10 exchange control messages 14 that result in the tiE 10 being moved from the CELL_FACH state or CELL_DCH state to one of the paging states CELL_PCH or URA_PCH as known per se.

At this point, the tiE 10 may determine that ideal ly it would like to move from the paging channel CELL PCH or URA PCH state to the Idle Mode state in order to achieve maximum power savings and therefore typically longer battery life in the case of the UE 10 being a mobile device. As noted above, in the case of a 3GPP system, this can be achieved by so-called Fast Dormancy, with the tiE 10 sending a transition request message to the network 11 for this purpose. As noted above, however, not all networks support and/or enable transitioning liEs to the Idle Mode state as part of the Fast Dormancy procedure. In this example of an embodiment of the present invention, therefore, the network 11 sends a system information (SI) message 15 to the liE 10 that indicates whether or not the network 11 enables Fast Dormancy transition to Idle Mode. This SI message 15 may effectively be broadcast to all tiEs serviced by the network 11, and may for example be sent repeatedly by the network 11 at a predetermined repetition rate. The SI message 15 may in practice be received by the UE 10 on one or more of a number of different occasions. For example, in the example shown in Figure 2, the SI message 15 is received after the above-discussed reconfiguration of the UB 10 from the data transfer CELL_EACH or CELL_DCH state to the paging channel CELL_PCH or URA_PCH state has been completed. However, to be effective, this SI message 15 may be received at any time prior to this. For example, this SI message 15 may be received when the UE 10 fir st connects to the cell serviced by the network 11, as part of the registration procedure S for example. As another example, this SI message 15 may be received by the UE 10 at or around the time that the UE 10 transitioned to the data transfer CELL FACH or CELL_DCH state, for example as part of the reconfiguration process that caused the UF 10 to move to that data transfer state or shortly thereafter. As yet another cxamplc, this SI message 15 may be received by thc UE 10 after sending the SCM 13 that includes the cause value "UE Rcqucstcd PS Data session end" discussed abovc.

On receipt of this SI message 15 indicating whether or not the network 11 enables Fast Dormancy transition to Idle Mode, the UE 10 can then determine whether or not to send a request to the network 11 to be moved to the Idle Mode state.

As indicated at A in Figure 2, if the SI message 15 indicates that the network 11 does support a Fast Dormancy transition to Idle Mode, the UE 10 determines to send a request to the network 11 to be moved to the Idle Mode state. To achieve this, the UE first exchanges control messages 16 with the network 11 to move to the CELL_FACH or CELL_DCH state. Then the UE 10 sends a request 17 to the network 11 to be moved to the Idle Mode state. As is known per se, this request 17 may bc sent by the UE 10 after a timer (iimcr T323") has expired, the UE 10 sending an SCM message 17 with an information element (IE) "Signaling Connection Release Indication Cause" (SCM with Cause) to the network 11. As mentioned, as an alternative, this transition request may be sent in a "Cell Update" or a "URA (user registration arca) Update" message. In any event, thc UE 10 and network 11 then exchange control messages 18 to release the RRC Connection and move the UE 10 to the Idle Mode state. On the other hand, as indicated at B in Figure 2, if the SI message 15 indicates that the network 11 does not support a Fast Dormancy transition to Idle Mode, the UE 10 determines not to send any request to the network 11 to be moved to the Idle Mode state.

Thus, by virtue of the network 11 indicating in advance whether or not it is capable of acting on a request from a UE 10 to transition the TIE 10 to Idle Mode from a paging channel state (including for example CELL PCH or URA PCH), or indeed any other state, the UE 10 only moves up to the data transfer state (such as S CELL FACH or CELL DCH in this example) as required to send a corresponding transition request message when the UE 10 knows that the network 11 has that feature enabled. If not, then the UE 10 does not move up to the data transfer state, with its associated higher rate of power consumption, and does not send unnecessary control signals. This saves wasting power and sending control signals needlessly. This represents a particular saving in the case that the TIE 10 would normally send repeated requests to be moved to the Idle Mode state as discussed further above. Moreover, in this example, where the indication is sent as a system information (SI) message 15, this can be achieved by a single bit being used for or added to the SI message and therefore requires minimal complexity and overhead.

Alternatively or additionally, the IJE 10 may be configured such that if it does not receive or has not received any message from the network 11 indicating whether or not the network 11 has Fast Dormancy transition to Idle Mode enabled, then the TIE 10 does not send any request to be moved to the Idle Mode state. In other words, in the absence of receipt of a message from the network 11 indicating whether or not the network 11 has Fast Dormancy transition to Idle Mode enabled, the TIE 10 effectively assumes that the network 11 does not support such a transition, similar to option B discussed above. This option may be particularly useful for implementation in IJEs immediately as it does not rely on changes being made to operation of the network 10 (in particular to send messages indicating whether or not the network 11 has Fast Dormancy transition to Idle Mode enabled as discussed above). This option may be used in combination with the example discussed above, as a "failsafe" such that the default is that the LIE 10 does not request a Fast Dormancy transition to Idle Mode unless the UE 10 has received a positive indication that the network 11 has such a transition enabled. It should be noted that the TIE 10 may not receive a message from the network indicating whether or not the network has Fast Dormancy transition to Idle Mode enabled because the network is not configured to send such messages (as is the ease in current, "legacy" networks) or because of some failure in the message being transmitted by the network and/or received at the UE, perhaps due to poor radio conditions or other loss of coverage.

S

Indeed, in a variation of this, in another example, the network 11 may be arranged to indicate only that Fast Dormancy transition to Idle Mode is enabled (for networks for which this is the ease, of course) and not to send any "negative" indication that the transitions are not supported. In this example, the UE 10 is arranged again only to send a request to the network 11 for a Fast Dormancy transition to Idle Mode as desired by the liE 10 if the liE 10 has received an indication from the network 11 that this feature is enabled for the network 11 Otherwise, if no such indication from the network 11 has been received, the UE 10 does not send any requests for a Fast Dormancy transition to Idle Mode. This again saves unnecessary exchanges of control signals between the UE 10 and the network II and also saves power at the liE 10.

In current arrangements, in effect the liE 10 assumes that Fast Dormancy transition to Idle Mode is enabled by the network 11, particularly if the Timer T323 is signalled. As another example of an embodiment of the present invention, the network 11 may be arranged to indicate only that Fast Dormancy transition to Idle Mode is not enabled (for networks for which this is the case, of course) and not to send any "positive" indication that the transitions are supported. In this example, the liE 10 may be arranged to send a request to the network 11 for a Fast Dormancy transition to Idle Mode as desired by the liE 10 unless the liE 10 has received an indication from the network II that this feature is not enabled for the network 11.

This again saves unnecessary exchanges of control signals between the liE 10 and the network II and also saves power at the tiE 10.

Figure 3 shows a schematic message sequence diagram relating to another example of an embodiment of the present invention. In this example, again a UE 10 and the network 11 (i.e. the base station, Node B, evolved Node B (eNB), network control apparatus, etc., including as a particular example a UTRAN (Universal Terrestrial Radio Access Network)) exchange data and messages. In sequence moving down the diagram shown in Figure 3, the UE 10 and network 11 transfer packet data 22. Once the current packet data transfer 22 has ended, the UE 10 can request the network 11 to move the UE 10 to a lower power consumption state, such as the CELL PCH or URA PCH state in the case of a 3GPP UMTS network. In this example of a 3GPP UMTS network, this is achieved by the UF 10 sending a RRC SIGNALLING CONNECTION RELEASE INDICATION (SCRI) 23 that includes the cause value "UE Requested PS Data session end". Again, as an alternative, this transition request may be sent in a "Cell Update" or a "URA (user registration area) Update" message. In any event, in response, the network 11 sends a message 24 that reconfigures the UE 10 to the CELL_PCH or URA_PCH state. As conventional, this message includes Radio Bearer Reconfiguration, Transport Channel Reconfiguration or Physical Channel Reconfiguration components. Furthermore, in this example, this RRC reconfiguration message 24 also contains an indication as to whether or not the network 11 has Fast Dormancy transition to Idle Mode enabled. This is in contrast to the example discussed above in which a specific SI message 15 is used to provide this indication.

The UE 10 responds with a RRC reconfiguration complete message 25, which includes Radio Bearer Reconfiguration Complete, Transport Channel Reconfiguration Complete or Physical Channel Reconfiguration Complete components. The UE 10 then transitions to the CELL PCFI or URA PCH state 26.

In an option X shown schematically in Figure 3, the UE 10 may reselect 27 to a new cell or URA (user registration area) at this point. In this ease, the UE 10 sends a Cell Update Request or a URA Update Request 28 to the network 11, which responds with a Cell Update Confirm or a URA Update Confirm 29. In this example, the Confirm message 29 includes contains an indication as to whether or not the Fast Dormancy transition to Idle Mode is enabled by the network 11 on the new cell. The TIE 10 then transitions to the CELL PCH or URA PCH state 30.

In either case, whether the UE 10 has remained with the original cell or URA S or moved to a new cell, the procedure is then similar to the example described above.

As indicated at Y in Figure 3, if the network 11 has indicated in one or other of the RRC messages 24,29 that the network 11 does support a Fast Dormancy transition to Idle Mode, the UF 10 determines to send a request to the network 11 to be moved to the Idle Mode state. To achieve this, the UE 10 first exchanges control messages 31 with the network 11 to move to the CELL FACH or CELL DCH state. Then the UE sends a request 32 to the network 11 to be moved to the Idle Mode state. Again as is known per se, this request 32 may be sent by the UE 10 after a timer ("Timer T323") has expired, the UE 10 sending an SCRI message 32 with an information element (IE) "Signaling Connection Release Indication Cause" (SCRI with Cause) to the network 11. Or, as an alternative, this transition request may be sent in a "Cell Update" or a "URA (user registration area) Update" message. The UE 10 and network 11 then exchange control messages 33 to release the RRC Connection and move the UE 10 to the Idle Mode state. On the other hand, as indicated at Z in Figure 3, if the network 11 has indicated in one or other of the RRC messages 24,29 that the network 11 does not support a Fast Dormancy transition to Idle Mode, the UE 10 determines not to send any request to the network 11 to be moved to the Idle Mode state. As discussed above, alternatively or additionally, the UE 10 may be configured such that if it does not receive or has not received any indication from the network 11 indicating whether or not the network 11 has Fast Dormancy transition to Idle Mode enabled, then the UE 10 does not send any request to be moved to the Idle Mode state.

In addition, similar to the further examples described above, the network 11 may be arranged to indicate only that Fast Dormancy transition to Idle Mode is enabled (for networks for which this is the case, of course) and not to send any "negative" indication that the transitions are not supported, or the network 11 may be arranged to indicate only that Fast Dormancy transition to Idle Mode is not enabled (for networks for which this is the case, of course) and not to send any "positive" indication that the transitions arc supportcd, with thc TiE 10 bcing arrangcd to act accordingly as dcscribcd abovc.

This second example therefore operates similarly to the first example, except S that the indication from the network 11 as to whether or not it has Fast Dormancy transition to Idle Mode enabled is sent as part of RRC reconfiguration messages, and/or via a celL/user registration area update confirm message, rather than as a dedicated SI mcssagc. This may bc preferred in some implementations as some dcdicatcd channels, which arc uscd for transmitting SI messages, already havc a limited capacity in practicc.

Thus, in some examples of embodiments of the present invention, in the abscncc of rcccipt of a flag or some othcr indication in a systcm information (SI) mcssagc or an RRC rcconfiguration mcssagc or via a ccH/uscr rcgistration arca updatc confirm message that indicates that a network has Fast Dormancy transition to Idle Modc cnabled, a IJE can avoid scnding multiplc Fast Dormancy rcqucsts to bc movcd to Idle Mode, which saves power at the TIE and keeps down the number of control signals that are sent. In certain embodiments, this can be achieved without making any changes to operation of current networks, though in other embodiments the opcration of thc network is such as to provide a spccific indication as to whcthcr or not thc nctwork has Fast Dormancy transition to IdIc Modc cnabled, with thc UE acting accordingly as described in more detail above.

Although at least some aspects of the embodiments described herein with rcfcrcncc to thc drawings comprisc computer processes performcd in processing systems or processors, the invention also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice.

Thc program may bc in thc form of non-transitory sourcc codc, object codc, a codc intermediate source and object code such as in partially compiled form, or in any other non-transitory form suitable for use in the implementation of processes according to the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a solid-state drive (SSD) or other semiconductor-based RAM; a ROM, for example a CD ROM or a semiconductor ROM; a magnetic recording medium, for example a floppy disk or hard disk; optical memory devices in general; etc.

S

It will be understood that the processor or processing system or circuitry referred to herein may in practice be provided by a single chip or integrated circuit or plural chips or integrated circuits, optionally provided as a chipset, an applieat ion-specific integrated circuit (ASIC), field-programmable gate array (FPGA), digital signal processor (DSP), etc. The chip or chips may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry, which are configurable so as to operate in accordance with the exemplary embodiments. Tn this regard, the exemplary embodiments may be implemented at least in part by computer software stored in (non-transitory) memory and executable by the processor, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware).

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. For example, the various indications that may be sent by the network 11 mentioned above may be sent in another form, or on other occasions, such as in a UTRAN Mobility Information message, or as some new, separate and dedicated message entirely. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defmed in the accompanying claims.

Claims

CLAIMS1. A method of operating a wireless device, the method comprising: the wireless device being in a data transfer state in order to be capable of S engaging in data transfer with a base station; and the wireless device transitioning from the data transfer state to a paging channel state on completion of data transfer with a said base station; the wireless device transitioning from the paging channel state to an idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.
2. A method according to claim 1, wherein to transition to the idle state, the wireless device is required to send a transition request to a said base station and to receive an instruction in response thereto to instruct the wireless device to transition to the idle state, the wireless device being arranged to send a said transition request only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.
3. A method according to claim 2, wherein the transition request is a Fast Dormancy request.
4. A method according to claim 2 or claim 3, comprising: the wireless device receiving an indication from a said base station as to whether or not said base station enables transition of the wireless device to the idle state; the wireless device determining that it would like to transition to an idle state; and, if the received indication from said base station indicates that said base station enables transition of the wireless device to the idle state, the wireless device sending a said transition request to said base station.
5. A method according to any of claims Ito 4, wherein the indication from a said base station is received as at east one of a system information message, as part of a radio resource configuration message, and via a cell!user registration area update confirm message.
6. A method according to any of claims 1 to 5, wherein the data transfer state is a Universal Mobile Telecommunications System (UMTS) CELL FACH state or CELL DCII state, the paging channel state is a UMTS CELL PCI-I or LJRAPCH state, and the idle state is a UMTS Idle Mode state.
7. A method of operating a wireless device, the method comprising: the wireless device determining that it would like to transition from a non-idle state to an idle state; the wireless device determining whether it has received an indication from a said base station that said base station enables transition of the wireless device to the idk state; and the wireless device sending a transition request to a said base station to request an instruction to transition to the idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.
S. A method according to claim 7, comprising: the wireless device receiving an indication from a said base station that said base station enables transition of the wireless device to the idle state; and the wireless device sending a said transition request to said base station.
9. A method according to claim 7 or claim 8, wherein the indication from a said base station is received as at least one of a system information message, as part of a radio resource configuration message, and via a cell!user registration area update confirm message.
10. A method according to any of claims 7 to 9, wherein the transition request is a Fast Dormancy request.
11. Amethodaccordingto anyofclaims 7to 10, whereinthenon-idle stateisa UMTS CELL_PCH or URA_PCH state, and the idle state is a UMTS Idle Mode state.
12. Apparatus comprising a processing system fbr a wireless device that is operable in an idle state and at least one non-idle state, the processing system being constructcd and arranged to: determine whether a said wireless device has received an indication from a base station that said base station enables transition of the wireless device to the idle state; and cause the wireless device to send a transition request to a said base station to request an instruction to transition from a non-idle state to the idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.
13. Apparatus according to claim 12, wherein the transition request is a Fast Dormancy request.
14. Apparatus according to claim 12 or claim 13, wherein the processing system is arranged to process an indication from a base station that said base station enables transition of the wireless device to the idle state that is received as at least one of a system infbrmation message, as part of a radio resource configuration message, and via a cell/user registration area update confirm message.
15. A wireless device comprising apparatus according to any of claims 12 to 14.
16. A computer program thr a wireless device, the computer program comprising instructions such that when the computer program is executed on a processing system of the wireless device, the wireless device is arranged to: detcrminc that it would likc to transition from a non-idlc statc to an idic state; determine whether it has rcccivcd an indication from a said base station that said base station enables transition of the wireless device to the idle state; and send a transition request to a said base station to request an instruction to S transition to the idle state only if the wireless device has received an indication from a said base station that said base station enables transition of the wireless device to the idle state.
17. A computer program according to claim 16, wherein the transition rcqucst is a Fast Dormancy rcqucst.
18. A method of operating a cellular network base station, the method comprising: if thc basc station enables transition of a wirciess dcvicc scrviced by thc basc station from a non-idle statc to an idle statc, the base station transmitting an indication that the base station enables transition of a wireless device serviced by the base station from the non-idle state to the idle state.
19. A method according to claim 18, comprising transmitting the indication as at least one of a system information message, as part of a radio resource configuration message, and via a cell/user registration area update confirm message.
20. Apparatus comprising a processing system for a cellular network base station, the processing system being constructed and arranged to: cause the base station to transmit an indication that the base station enables transition of a wireless device serviced by the base station from a non-idle state to an idle state if the base station enables transition of a wireless device serviced by the base station to the idle state from the non-idle state.
21. Apparatus according to claim 20, arranged such that the indication is transmitted as at least one of a system information message, as part of a radio resource configuration message, and via a celliuser registration area update confirm message.
22. A cellular network base station comprising apparatus according to claim 20 or claim2l.
23. A computer program for a cellular network base station, the computer program comprising instructions such that when the computer program is executed on a processing system of the base station, the base station is arranged to: transmit an indication that the base station enables transition of a wireless device serviced by the base station from a non-idle state to an idle state if the base station enables transition of a wireless device serviced by the base station to the idle state from the non-idle state.
24. A computer program according to claim 23, comprising instructions such that the indication is transmitted as at least one of a system information message, as part of a radio resource configuration message, and via a cell/user registration area update confirm message.
25. A method of operating a wireless device, the method comprising: the wireless device determining that it would like to transition from a non-idle state to an idle state; and the wireless device sending a transition request to a said base station to request an instruction to transition to the idle state unless the wireless device has received an indication from a said base station that said base station does not enable transition of the wireless device to the idle state.
26. A method according to claim 25, wherein the indication from a said base station is received as at least one of a system information message, as part of a radio resource configuration message, and via a cell/user registration area update confirm message.
27. A method according to claim 25 or claim 26, wherein the transition request is a Fast Dormancy request.
28. A method according to any of claims 25 to 27, wherein the non-idle state is a UMTS CELL PCH or URA PCH state, and the idle state is a TiNTS Idle Mode state.
29. Apparatus comprising a processing system for a wireless device that is operable in an idle state and at least one non-idle state, the processing system being constructed and arranged to: detcrminc that it would like the wireless dcvicc to transition from a non-idle state to an idle state; and cause the wireless device to send a transition request to a said base station to request an instruction to transition to the idle state unless the wireless device has received an indication from a said base station that said base station does not enable transition of the wireless device to the idle state.
30. Apparatus according to claim 29, wherein the transition request is a Fast Dormancy request.
31. Apparatus according to claim 29 or claim 30, wherein the processing system is arranged to process an indication from a base station that said base station does not enable transition of the wireless device to the idle state that is received as at least one of a system information message, as part of a radio resource configuration message, and via a cell/user registration area update confirm message.
32. A wireless device comprising apparatus according to any of claims 29 to 31.
33. A computer program for a wireless device, the computer program comprising instructions such that when the computer program is executed on a processing system of the wireless device, the wireless device is arranged to: determine that it would like to transition from a non-idle state to an idle state; and send a transition request to a said base station to request an instruction to transition to the idle state unless the wireless device has received an indication from a S said base station that said base station does not enable transition of the wireless device to the idle state.
34. A computer program according to claim 33, wherein the transition request is a Fast Dormancy request.
35. A method of operating a cellular network base station, the method comprising: if the base station does not enable transition of a wireless device serviced by the base station from a non-idle state to an idle state, the base station transmitting an indication that the base station does not enaNe transition of a wirdess device serviced by the base station from the non-idle state to the idle state.
36. A method according to claim 35, comprising transmitting the indication as at least one of a system information message, a radio resource configuration message, and as part of a cell update confirm message or a user registration area update confirm message.
37. Apparatus comprising a processing system for a cellular network base station, the processing system being constructed and arranged to: cause the base station to transmit an indication that the base station does not enable transition of a wireless device serviced by the base station from the non-idle state to the idle state if the base station does not enable transition of a wireless device serviced by the base station from a non-idle state to an idle state.
38. Apparatus according to claim 37, arranged such that the indication is transmitted as at least one of a system information message, a radio resource configuration message, and as part of a cell update confirm message or a user registration area update confirm message.
39. A cellular network base station cowpiising apparatus according to claim 37 or claim38.
40. A computer program fbr a cellular network base station, the computer program coiiipiising instructions such that when the computer program is executed on a pmccssing system of thc base station, thc base station is arranged to: transmit an indication that thc base station does not enable transition of a wireless device serviced by the base station from the non-idle state to the idle state if the base station does not enable transition of a wireless device serviced by the base station from a non-idle state to an idle state.
41. A computer program according to claim 40, comprising instructions such that the indication is transmitted as at least one of a system inlbrmation message, a radio resource configuration message, and as part of a cell update confirm message or a user registration area update confirm message.
42. A method of operating a wireless device, substantially in accordance with any of the examples as described herein with reference to and illustrated by the accompanying drawings.
43. A wireless device, substantially in accordance with any of the examples as described herein with reibrence to and illustrated by the accompanying drawings.
44. A method of operating a cellular network base station, substantially in accordance with any of the examples as described herein with reibrence to and illustrated by the accompanying drawings.
45. A cellular network base station, substantially in accordance with any of the examples as described herein with reference to and illustrated by the accompanying drawings.