WO2010063499A1

WO2010063499A1 - Method and apparatus for paging with carrier aggregation

Info

Publication number: WO2010063499A1
Application number: PCT/EP2009/061694
Authority: WO
Inventors: Lei Du; Min Huang; Yong Teng
Original assignee: Nokia Siemens Networks Oy
Priority date: 2008-12-05
Filing date: 2009-09-09
Publication date: 2010-06-10
Also published as: GB0822280D0

Abstract

A method comprising sending on each of a plurality of carriers, said plurality of carriers being aggregated together, a respective paging message.

Description

DESCRIPTION

TITLE: METHOD AND APPARATUS FOR PAGING WITH CARRIER AGGREGATION

BACKGROUND

Field of the Invention:

The present invention relates to a method and apparatus for paging messages.

Description of related art:

A communication device can be understood as a device provided with appropriate communication and control capabilities for enabling use thereof for communication with others parties. The communication may comprise, for example, communication of voice, electronic mail (email) , text messages, data, multimedia and so on. A communication device typically enables a user thereof to receive and transmit communication via a communication system. A communication device can thus be used for accessing various service applications.

A communication system is a facility which facilitates communication between two or more entities such as communication devices, network entities and other nodes. A communication system may be provided by one or more interconnect networks . One or more gateway nodes may be provided for interconnecting various networks of the system. For example, a gateway node is typically provided between an access network and other communication networks, for example a core network and/or a data network . An appropriate access system allows the communication device to access to the wider communication system. An access to the communication system may be provided by means of a fixed line or wireless communication interface, or a combination of these. Communication systems providing wireless access typically enable at least some mobility for the users thereof, hence the name mobile systems. Examples of mobile systems include wireless communications systems where the access is provided by means of an arrangement of cellular access networks. Other examples of wireless access technologies enabling at least a degree of mobility include different wireless local area networks (WLANs), ad-hoc wireless networks and satellite based communication systems .

A wireless access system typically operates in accordance with a wireless standard and/or with a set of specifications which set out what the various elements of the system are permitted to do and how that should be achieved. For example, the standard or specification may define if a user, or more precisely user equipment, is provided with a circuit switched bearer or a packet switched bearer, or both. Communication protocols and/or parameters which should be used for the connection are also typically defined. For example, the manner in which communication should be implemented between the user equipment or another communication device and the elements of the networks and their functions and responsibilities are typically defined by a predefined communication protocol.

In the cellular systems a network entity in the form of a base station provides a node for communication with mobile devices in one or more cells or sectors. It is noted that in certain systems a base station is called ^xNode B' . Typically the operation of a base station apparatus and other apparatus of an access system required for the communication is controlled by a particular control entity. The control entity is typically interconnected with other control entities of the particular communication network. Examples of cellular access systems include Universal Terrestrial Radio Access Networks (UTRAN) and GSM (Global System for Mobile) EDGE (Enhanced Data for GSM Evolution) Radio Access Networks (GERAN) .

A non-limiting example of another type of access architectures is a concept known as the Evolved Universal Terrestrial Radio Access (E-UTRA) . An Evolved Universal Terrestrial Radio Access Network (E-UTRAN) consists of E-UTRAN Node Bs (eNBs) which are configured to provide base station and control functionalities of the radio access network. The eNBs may provide E-UTRA 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 mobile devices.

Paging is a mechanism for distributing information to multiple user equipment. There may be a problem with some systems in how and where to schedule paging messages so that use equipment can identify their respective paging messages.

SUMMARY OF INVENTION

According to a first aspect of the present invention, there is provided a method comprising sending on each of a plurality of carriers, said plurality of carriers being aggregated together, a respective paging message.

According to a second aspect of the present invention, there is provided a method comprising monitoring one of a plurality of aggregated carriers for a paging message. According to a third aspect of the present invention, there is provided an apparatus comprising means for providing a respective paging message for sending on each of a plurality of carriers, said plurality of carriers being aggregated together, a respective paging message.

According to a fourth aspect of the present invention, there is provided an apparatus comprising means for monitoring one of a plurality of aggregated carriers for a paging message.

According to a fifth aspect of the present invention, there is provided a method comprising formulating respective paging messages; sending via a transmission arrangement on each of a plurality of carriers, said plurality of carriers being aggregated together, said respective paging messages.

BRIEF DESCRIPTIONS OF THE DRAWINGS

For a better understanding of various examples of the present invention and how the same may be carried into effect, reference will now be made by way of example only to the accompanying drawings in which:

Figure 1 shows schematically a know example of paging occasions;

Figure 2 shows carrier aggregation as proposed for LTE-A (long term evolution- advanced);

Figure 3 shows an embodiment where the paging occasions are synchronised and repeated over the aggregated carriers;

Figure 4 shows an embodiment where the paging occasions are repeated but offset over the component carriers; Figure 5 shows an embodiment where the paging occasions are synchronised but not repeated over the aggregated carriers;

Figure 6 shows an embodiment where the paging occasions are offset and not repeated over the aggregated carriers;

Figure 7 shows a schematic presentation of a communication architecture wherein the inventions may be embodied; and

Figure 8 shows a schematic view of a base station in which embodiments of the invention may be embodied.

DESCRIPTION OF EXEMPLIFYING EMBODIMENTS

Embodiments of the invention may be used in the context of long term evolution advanced (LTE-A) system of 3GPP (third generation partnership project) . However it should be appreciated that embodiments of the present invention may be used in other LTE systems as well as non LTE standards.

In some embodiments of the invention, a paging procedure for a wide bandwidth consisting of multiple component carriers is provided. These carriers may be aggregated together. The purpose of paging procedure is to transmit paging information to a UE (user equipment) and/or to inform UEs about a system information change or provide information to a UE. For example the paging mechanism can provide an Earthquake and Tsunami Warning System primary notification such as described in 3GPP specification TR 36.331 v8.3.0

For example if the UE receives a paging message including the etws-PrimaryNotificationlndication, the UE knows that the ETWS primary notification is present.

The Paging message may be used to inform UEs about a system information change. If the UE receives a Paging message including the systemlnfoModification, it knows that the system information changes at the next modification period boundary.

The paging message may include one or more of the following elements : - pagingRecordList : a sequence of set {ue-Identity, en-Domain, pagingCause } systemlnfoModification: if present, it shows an indication of a BCCH (Broadcast control channel) modification etws-PrimaryNotificationlndication: if present, it shows an indication of an ETWS primary notification.

The paging message is initiated by E-UTRAN at the UE' s paging occasions (PO) . Upon receiving the Paging message, the UE shall: 1> If in RRC_(radio resource control) IDLE mode, for each of the Paging records included in the Paging message:

2>If the ue-identity included in the pagingRecordList matches one of the UE identities allocated by upper layers:

3> forward the ue-Identity, the en-Domain and the pagingCause to the upper layers. 1> If the systemlnfoModification is included:

2> re-acquire the required system information using the system information acquisition procedure

1> If the etws-PrimaryNotificationlndication is included and the UE is ETWS capable:

2>re-acquire SystemlnformationBlockTypel immediately, i.e., without waiting until the next system information modification boundary;

2>acquire SystemlnformationBlockTypelO; 2> if the schedulinglnformation indicates that SystemlnformationBlockTypell is present: 3> acquire SystemlnformationBlockTypell ;

It should be appreciated that this is by way of example and the paging message may include only one or some of the fields discussed above. In alternative embodiments of the invention additional or alternative fields may be required.

Currently, when the public land mobile network (PLMN) receives a call for a registered UE, the PLMN shall send a "paging" message for the UE on control channels of all the cells in the set of tracking areas where the UE is camped. The UE will then receive the paging message over the control channel it is tuned to and can respond on that control channel.

As specified in the 3GPP specification, TS 36.304, a paging message is originated at a MME (mobility management entity) and scheduled by an eNB at UE-specific paging occasions (PO) . The UE may use discontinuous reception (DRX) in idle mode to monitor only one PO per DRX cycle in order to reduce power consumption. For each UE, its paging frame (PF) and PO is determined by the following formulae using the DRX parameters provided in system information : - PF is given by following equation: SFN mod T = (T div N) * (UE_ID mod N)

- Index i_s pointing to PO from subframe pattern defined in table 1 will be derived from following equation: i_s = floor (UE_ID/N) mod Ns wherein

SFN - system frame number

T: the default paging cycle, also referred to as DRX cycle, in which a UE wakes up once to monitor the paging occasion. The range of values is currently 32, 64, 128, 256 radio frames where one radio frame is 10ms nB : a parameter to derive the number of paging groups with value [4T, 2T, T, 1/2T, 1/4T, 1/8T, 1/16T, 1/32T] .

N: number of paging groups within one paging cycle, min (T, nB) ;

- Ns: max (1, nB/T)

UE_ID: IMSI (international mobile subscriber identity) mod 1024, IMSI is interpreted as a decimal integer number.

The following table gives the subframe pattern in a FDD (frequency duplex division) system and a TDD (time duplex division) system respectively. These tables show subframe patterns for i_s by which the PO can be decided. FDD:

Ns PO when PO when PO when PO when i_s=0 i_s=l i_s=2 i_s=3

1 9 N/A N/A N/A

2 4 9 N/A N/A

4 0 4 5 9

TDD (all UL/DL (uplink/downlink patterns) :

Ns PO when PO when PO when PO when i s=0 i s=l i s=2 i s=3

Reference is made to Figure 1 which shows an example of paging occasions for the UEs with UE_ID = 12 and UE_ID = 13 respectively. By way of example T = 32 radio frames, nB = T/8, N = 4, Ns = max ( 1 , nB/T) . Each paging cycle comprises 32 radio frames. Figure 1 represents the transmission from a particular base station. It should be appreciated that different parts of the transmission may be provided by different base stations in alternative embodiments or situations. It is possible in alternative embodiments or situations that more than one base station may be providing the transmission shown in Figure 1.

One paging cycle comprises 32 radio frames. The first line of figure 1 represents some of the 32 radio frames of the paging cycle. MIB (master information block) is most frequently transmitted parameters that are needed to acquire other information from the cell, e.g. the downlink system bandwidth, physical HARQ (hybrid automatic repeat request) indication channel (PHICH) configuration and system frame number. The MIB uses a fixed schedule with, for example, a periodicity of 40 ms and repetitions made within 40 ms . The first transmission of the

MIB is scheduled in subframe #0 of radio frames for which the

SFN mod 4 = 0, and repetitions are scheduled in subframe #0 of all other radio frames.

As can be seen from the first line of Figure 1, the MIB is scheduled at 40ms intervals. As can be shown in the second line of Figure 1, the MIB is repeated at 10ms interval, i.e. one radio frame. As can be seen from the second line of Figure 1, the paging frame 24 and 26 occurs at regular intervals, every 8 frames. This is because N has been set to 4. Two of the paging frames are shown. Each paging frame comprises a respective paging occasion 27 and 29. The bottom line of Figure 1 shows just the POs 27 and 29. Two POs are shown, one for UE_ID12 and one for UE_ID 13. Each UE will decide its paging frame and paging occasion based on its ID. So when UE_ID = 12, its PF will occur in the radio frames where SFN mod T = O, i.e. there is only one PF for one UE during a paging cycle. That is to say, the PO for UE with UE_ID = 12 is 27 inside paging frame 24. There is no PO for this UE in paging frame 26.

It has been proposed that 3GPP technical specification TS 36.913 that LTE-A should operate in spectrum allocations of different sizes including wider spectrum allocations than those of Release 8 LTE, e.g. up to 100MHz, to achieve the peak data rate of 100Mbit/s for high mobility and 1 Gbit/s for low mobility.

Optionally LTE-A may be compatible with Release 8 LTE in the sense that a Release 8 LTE terminal can work in LTE-A system and that a LTE-A terminal can work in an Release 8 LTE system. Release 8 is an earlier version of LTE as compared to LTE- advanced.

In RANl#53bis and #54, it was agreed that carrier aggregation is considered for LTE-Advanced in order to support bandwidths larger than 20 MHz, which is specified in the 3GPP document Rl- 084015, draft 36.814 vθ.1.0, "further Advancements for E-UTRA physical layer aspects":

Carrier aggregation is where two or more component carriers are aggregated. This has been is considered for LTE-Advanced in order to support downlink transmission bandwidths larger than 20 MHz. A terminal may simultaneously receive one or multiple component carriers depending on its capabilities:

• An LTE-Advanced terminal with reception capability beyond 20 MHz can simultaneously receive transmissions on multiple component carriers .

• An LTE Rel-8 terminal can receive transmissions on a single component carrier only, provided that the structure of the component carrier following the Release 8 specifications.

Reference is made to Figure 2 which shows an example of the carrier aggregation. M Rel8 bandwidth "chunks", or component carriers, are combined together to form MxRelδ BW (bandwidth) , e.g. 5 x 20MHz = IOOMH given M = 5. In Figure 2, five 20Mhz bandwidth elements 30a-30e are shown. These are aggregated together to give one LTE advanced maximum bandwidth 32 of 100MHz. The Release 8 terminals receive/transmit on one component carrier, whereas LTE-Advanced terminals may receive/transmit on multiple component carriers simultaneously to reach the higher bandwidths .

When the multiple component carriers are aggregated together, the control signalling to address the extended bandwidth is addressed by some embodiments of the invention. As regards the paging procedure, how and where to schedule the paging messages so that UEs can identify their respective paging occasions is addressed by some embodiments of the invention.

In some embodiments of the present invention, the basic paging method can be described as below: - eNB schedules the paging message for UE on specific paging occasions .

The UE monitors the specific paging occasions and checks whether there is paging message addressing to its identity and makes a response. In some embodiments a UE randomly selects one component carrier or multiple component carriers to monitor for the PCH (paging channel) . In another embodiment the UE decides one specific component carrier to monitor for the PCH.

Referring first to one embodiment where the UE randomly selects one or multiple component carrier to monitor for the PCH. Since it is unknown on which component carrier a UE would monitor the PCH, the paging messages are replicated on all the component carriers. That is, a paging message addressing to an LTE-A terminal would be visible on all the component carriers.

Reference is made to Figure 3 which illustrates this embodiment. - Paging messages are replicated on all the component carriers in the same paging occasions as is decided in LTE system. A UE randomly accesses to one component carrier or multiple component carriers, and calculates the paging frames and occasions as defined in above Generally a UE would not access all the component carriers but this may occur in some embodiments of the invention.

Figure 3 shows three of the aggregated carriers 30a-c. For clarity, two of the aggregated carriers are not shown. Each carrier has the structure illustrated in Figure 1. It should be appreciated that there is synchronisation between the carriers with the MIBs 36 occurring at the same time for each carrier component. Likewise the Paging Frames 34 occur at the same time in each carrier component .

Reference is made to Figure 4 which shows a further embodiment of the invention. In this arrangement the paging frames do not occur at the same time in each of the different carrier bandwidths . The positions of MIBs are the same for all the component carriers .

Paging frame 40 are provided on each component carrier by offsetting by alpha radio frames over the neighboring component carrier. alpha is an integer in some embodiments of the invention .

A PO is the index of a subframe within one radio frame, which is always the same for all the component carrier. The offset is thus for the PF.

For example in Figure 4, the PF 40 in the first carrier occurs at the beginning of the first line. In the next carrier bandwidth, the PF occurs alpha radio frames after that. In the next carrier bandwidth the PF occurs alpha radio frames after the preceding carrier bandwidth and two times alpha after the first carrier bandwidth and so on. The eNB includes alpha in system information and advertises to UEs explicitly, or alpha is implicitly agreed between eNB and UEs. E.g. alpha = 1 radio frame. alpha can of course be any other suitable value. UEs could calculate the offset on each component carrier by multiplying the received alpha with the index of its component carrier .

In an alternative embodiment or situation, where there are n carrier, there will be an offset of 0, alpha, two times alpha n times alpha. The offsets can be arranged in any order.

For example carrier 0 could have an offset of two alpha, carrier 1 an offset of 0, carrier 2 and offset of 3 times alpha and carrier four an offset of alpha. In other words adjacent carriers do not necessarily have a respective offset of alpha. The eNB includes alpha, the times of alpha on each component carrier and/or the value of offset on each component carrier in system information and advertises to UEs explicitly, or alpha is implicitly agreed between eNB and UEs. E.g. alpha = 1 radio frame. alpha can of course be any other suitable value. UEs could calculate the offset on each component carrier by multiplying the received alpha with the times or directly applying the received offset.

- In an alternate embodiment or situation, there may be more than one carrier which has the same offset with respect to a common reference The eNB includes alpha in system information and advertises to UEs explicitly, or alpha is implicitly agreed between eNB and UEs. E.g. alpha = 1 radio frame. alpha can of course be any other suitable value. The offsets on each component carrier may be advertised by the eNB, i.e. n offsets are advertised by system information. - In some embodiments, the position of the PO is not change, i.e. the subframe is not changed. The PF is however offset. In this embodiment, Alpha is an integer times of radio frame, i.e. 10ms. If alpha is defined in terms of subframe, it would change the PO. This can be done alternative embodiments of the invention.

A UE randomly accesses to one component carrier or multiple component carriers, and monitors the PCHs over all the selected component carriers. Assuming the component carrier index k (k = 0,1,...M-I, M is the total number of component carriers), the PFs (Paging frames) over component carrier #k may be decided as below:, Alternatively or additionally, that the eNode B advertises the index of the component carriers k to UEs on respective component carrier, so that UEs could decide their offset on their own. -

* PF is given by either of the following equations: (SFN - alpha x k ) mod T = (T div N) * (UE_ID mod N)

Or SFN mod T = (T div N) * (UE_ID mod N) + (alpha x k) mod (T div N) SFN is the system frame number.

Some of these embodiments may have one or more of the following advantages.

1) Gives more flexibility to UEs on their access because whichever component carrier a UE accesses, the UE can receive the paging message correctly.

2) A UE can select one component carrier to monitor the PCH which can help save power and/or reducing processing requirements.

3) The embodiment described in relation to Figure 4 may provide more scheduling flexibility by distributing the paging messages over time which can provide better gain and even resource utilization in different radio frames. 4) If a UE accesses multiple component carriers, the offset paging occasions in the arrangement shown in Figure 4 helps a UE quickly recognize the paging messages after only alpha radio frames, without having to defer to the whole paging cycle as in the arrangement shown in Figure 3.

In the arrangements shown in Figures 3 and 4, there is more flexibility on UEs' access, i.e. to any of the component carrier, however, paging messages are N times repeated within the whole bandwidth.

In the arrangements described in relation to Figure 5 and 6, the UEs access only one specific component carrier for the paging information. The paging message can be sent on this component carrier only so as to achieve the signalling efficiency. In some embodiments or alternative situations, that paging message for a specific UE can be sent on more than one of the carriers but not all of the carriers. The same references are used as compared to Figures 3 and 4, although the content of the paging channel may differ. Reference is made to Figure 5. In this embodiment:

Paging message is only sent on one specific component carrier without repetition over other component carriers. - UE decides the component carrier based on its UE_ID derived from the IMSI, and monitors the PCH over this component carrier whose index matches the calculated result. (eNB could indicate the index of component carrier to UE as well.) * The index of selected component carrier is: UE_ID mod M - UE calculates the paging frames and occasions over the selected component carrier as discussed previously in relation to Figure 1. The relative timing of the paging frames is generally as described in relation to Figure 3, the difference being that the paging frames occurring at the same time on the different component carriers are intended for different UEs.

Reference is now made to Figure 6 which describes an embodiment similar to that described in relation to Figure 4 but a paging message is only sent on specific component carrier without repetition over other component carriers. In other words, the paging information which is sent on the different carriers with the offsets intended for different UEs and/or contain different paging information.

Thus as with the embodiment shown in Figure 4, eNB includes alpha in system information and advertise to UEs explicitly, or alpha is implicitly agreed between the eNB and UEs. The UE decides the component carrier based on its UE_ID deriving from IMSI .

The index of the selected component carrier is: UE_ID mod M. The UE monitors the PCH over this component carrier, wherein PF is given by either of the following equations: (SFN - alpha x k ) mod T = (T div N) * (UE_ID mod N) Or SFN mod T = (T div N) * (UE_ID mod N) + (alpha x k) mod (T div N)

The proposal gives the solutions of deciding the paging frames and occasions in carrier aggregation systems. It provides efficient access for LTE-A terminals while guaranteeing the backward compatibility.

With the embodiments discussed in relation to Figure 5 and 6, there may be the following advantages:

1) The overhead is decreased by only sending the paging message on one component carrier.

2) A UE by selecting only one component carriers to monitor for PCH helps save power. 3) The paging occasion may be scheduled over different component carriers over the time scale, so as to provide more flexibility on scheduling.

It should be appreciated that in some embodiments of the invention, different ones of the above described embodiments may be used in different circumstance depending for example on one or more of the radio environment, quantity of traffic in the system, nature of the paging message or the like.

Considering the backward compatibility to Release 8 terminals, the paging frames and occasions addressed to Release 8 terminals or terminals operating in a Release 8 mode, this will be as described in relation to Figure 1.

The paging frames on each carrier are transmitted by an eNode B. For the aggregated carriers, the paging frames may be transmitted by a single eNode B. However in alternative embodiments or alternative situations, the paging frames for each of the aggregated carriers may be transmitted by two or more eNode Bs .

The carriers which are aggregated have adjacent frequencies. However it should be appreciated that non-adjacent carriers may also be aggregated.

Embodiments of the invention have been described in the context of aggregated carriers. However it should be appreciated that some embodiments of the invention may be applied in the context of a single carrier where paging messages are sent on sub- carriers of the single carrier.

Embodiments of the invention have been described in relation to the LTE-A system. However it should be appreciated that embodiments of the invention can be used in any appropriate alternative standard.

Reference will now be made to Figure 7 which shows a system in which embodiments of the present invention may be incorporated. Additionally, with reference to Figure 7, a brief explanation of the general principals of wireless communications in a system comprising a base station and a communication device such a mobile station will be provided.

In the exemplary embodiment of Figure 7, the system shown is a LTE radio system. As such, the term eNB is used for the base station function. A communication device or UE, for example a user device can be used for accessing various services and/or applications provided by a communication system. In wireless or mobile systems, the access is provided via an access interface between a user device 101 and an appropriate wireless access system. The user device can typically access wirelessly the communication system via at least one base station (eNB) 110 and 115. In the example shown, two eNBs are shown. In practice, many more will be provided.

The eNBs 110 and 115 can be connected to another system, for example a data network 112. A gateway function between an eNB and the other network can be provided by means of any appropriate gateway node 114, for example a packet data gateway and/or an access gateway. The eNB is typically controlled by at least one appropriate controller entity 116. The controller entity can be provided for managing of the overall operation of the eNB and communications via the eNB. The controller entity 116 is typically with memory capacity and at least one data processor. Functional entities may be provided in the controller by means of a data processing capability thereof.

In the embodiment shown in Figure 7, a single controller is provided. However, in practice more than one controller may be provided in a system and accordingly different eNBs will be connected to different controllers.

As discussed, embodiments of the present invention can be used in the long term evolution (LTE) radio system. The system provides an evolved radio access system that is connected to a packet data system. Such an access system may be provided, for example, based on architecture that is known from the E-UTRA

(evolved UMTS terrestrial radio access) and based on the use of

EUTRAN node Bs (eNBs) . An E-UTRAN comprises of E-UTRAN node Bs which are configured to provide base station and control functionalities .

It should be appreciated that Figure 7 shows example architectures only to give examples of possible communication systems where the embodiments described may be provided. It should be appreciated that other arrangements and architectures are also possible.

The user device 101 can be used for various tasks such as making and receiving phone calls, for receiving and sending data from and to a data network and for experiencing, for example multimedia or other content. For example, a user device may access data applications provided by a data network. The various applications may be offered in a data network based on the internet protocol (IP) or any other appropriate protocol.

An appropriate user device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile telephone, a mobile station, a portable computer provided with a wireless interface card or other wireless interface facility, a personal data assistant provided with wireless communication capabilities or any combination of these or the like.

The user device may communicate via an appropriate radio interface arrangement of the mobile device. The interface arrangement may be provided for example by means of a radio part 107 and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device. The antenna arrangement is arranged to receive the transmissions from the respective eNode B such as the paging channel and optionally the value of alpha, the index of component carrier. The mobile device is typically provided with at least data processing entity 103 and at least one memory 104 for use in the tasks that it is designed to perform. The antenna and/or the data processing processor can be tuned to the required carrier bandwidth or bandwidths for receiving the respective paging channel. For those embodiments where the paging channel is not provided on all the component carriers, the data processing entity may determine the carrier component (s) to monitor based on information received from the eNode B via the antenna and/or on the calculation performed by the data processing entity.

The function or functions provided by the data processing entity may be provided by a single entity or may be provided by plurality of entities.

The data processing and storage entities can be provided on an appropriate circuit board, in an integrated circuit or in chip set. This is denoted diagrammatically by reference 106.

Reference numeral 109 diagrammatically represents the measurement and reporting functionality. The user device makes some measurements for example relating to the channel quality and this is then reported back to the relevant eNB . It should be appreciated that the functionality indicated diagrammatically 109 may be formed at least partially by the data processing entity .

The user can control operation of the mobile device by means of a suitable user interface such as a keypad 102, voice command, touch-sensitive screen or pad, combination thereof or the like. A display 105, a speaker and a microphone are also typically provided. Furthermore, the mobile device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories such as hand- free equipment .

In Figure 8, the node B comprises an antenna 61 for receiving radio communication. The antenna 61 is connected to a receiver 60 which is in turn connected to a processor 68. The processor 68 is able to transmit to the user equipment by sending messages to the transmitter 58. The transmitter 58 passes the message for transmission to the antenna 61 for transmission. The processor 68 is also connected to an interface 66 which connected to controller 116. The eNB also comprises a memory 70 which can store various information as discussed in more detail hereinbefore. The processor is able to make the various determinations concerning the paging channel message content, the intended recipient (s) , and/or the index of component carrier and alpha, as appropriate. Alternatively, additionally or in combination the paging channel information, intended recipient and/or alpha maybe received from a further entity such as the controller or a mobility management entity either directly or indirectly .

It is noted that whilst embodiments have been described in relation to mobile communication devices such as mobile user equipment / terminals, embodiments of the present invention are applicable to any other suitable type of apparatus suitable for communication via access systems. A mobile device may be configured to enable use of different access technologies, for example, based on an appropriate multi-radio implementation.

It is also noted that although certain embodiments were described above by way of example with reference to the exemplifying architectures of certain mobile networks and a wireless local area network, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein. It is also noted that the term access system is understood to refer to any access system configured for enabling wireless communication for user accessing applications.

In general, the various embodiments of the invention may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto.

While various aspects of the invention 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 exemplary embodiments of this invention may be implemented by computer software executable by a data processor of the apparatus, such as in the processor entity, or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that the method are represented by the Figure and or description may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. 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 memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The 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) and processors based on multi-core processor architecture, as non-limiting examples. The processor or processors in some embodiments of the invention may be application specific integrated circuits (ASIC) or any form of data processing arrangement. For example the processors may be implemented using custom integrated circuit implementations, or using field programmable gate arrays (FPGA) or any technology using sea-of-gates configurations.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications 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 fall within the scope of this invention as defined in the appended claims .

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

CLAIMS :

1. A method comprising: sending on each of a plurality of carriers, said plurality of carriers being aggregated together, a respective paging message .

2. A method as claimed in claim 1, comprising sending substantially the same respective paging message on each of said plurality of carriers.

3. A method as claimed in claim 1 or 2, wherein said respective paging messages are intended for a specific one or more recipients.

4. A method as claimed in claim 1, wherein said different paging messages are intended for different recipients.

5. A method as claimed in claim 1 or 4, wherein said respective paging messages are each intended for different recipients .

6. A method as claimed in any preceding claim, comprising sending said respective paging messages on said different carriers at substantially the same time.

7. A method as claimed in any of claims 1 to 5, comprising sending said respective paging messages on said different carriers at different times.

8. A method as claimed in claim 7, comprising sending said respective paging messages such that each of said paging messages is offset by a predetermined time from a different one of said paging messages.

9. A method as claimed in claim 8, wherein said predetermined time comprises an integer number of radio frames.

10 A method as claimed in claim 8, wherein said predetermined time comprises a non integer number of radio frames.

11. A method as claimed in claim 8, 9 or 10, comprising sending information indicating the respective predetermined time to respective recipients.

12. A method as claimed in claim 11, comprising sending by a base station said information indicating said predetermined time .

13. A method as claimed in claim 11 or 12, comprising sending information indicating said respective predetermined times on respective, different carriers.

14. A method as claimed in claim 8, 9 or 10, comprising agreeing said predetermined time between a base station and respective recipients.

15. A method as claimed in any preceding claim, comprising sending information indicating a respective carrier for a respective recipient.

16. A method as claimed in any of claims 7 to 15, wherein a paging frame for said respective paging message is defined by: (SFN - alpha x k ) mod T = (T div N) * (UE_ID mod N) where SFN is the system frame number, alpha is a constant, k is a carrier index, T is the paging cycle,

N is the number of paging groups in paging cycle UE_ID is a IMSI of a user equipment.

17. A method as claimed in any of claims 7 to 15, wherein a paging frame for said respective paging message is defined by:

SFN mod T = (T div N) * (UE_ID mod N) + (alpha x k) mod (T div N) where SFN is the system frame number, alpha is a constant, k is a carrier index,

T is the paging cycle,

N is the number of paging groups in the paging cycle and UE_ID is a IMSI of a user equipment.

18. A method as claimed in any preceding claim, comprising sending on all of a plurality of carriers which are aggregated together said respective paging messages.

19. A method as claimed in any preceding claim, wherein said paging message is sent in a paging frame.

20. A method as claimed in any preceding claim, comprising sending, by a base station said respective paging messages.

21. A method as claimed in any preceding claim comprising sending a respective paging message to a respective recipient on a carrier, said carrier being selected in dependence on an index based on an identity of said recipient.

22. A method as claimed in claim 21, wherein said index is calculated by a user identity modulus number of radio frames in a paging cycle.

23. A method comprising monitoring one of a plurality of aggregated carriers for a paging message.

24. A method as claimed in claim 23, comprising monitoring said carrier with an index based on an identity of a monitoring entity for said paging message.

25. A computer program comprising program code means adapted to perform any of the steps of any of claims 1 to 24, when the program is run on a processor.

26. Apparatus comprising means for providing a respective paging message for sending on each of a plurality of carriers, said plurality of carriers being aggregated together, a respective paging message.

27. Apparatus as claimed in claim 26, wherein said means for providing provides substantially the same respective paging message for each of said plurality of carriers.

28. Apparatus as claimed in claim 26, wherein said means for providing respective paging messages, each intended for different recipients.

29. Apparatus as claimed in any of claims 26 to 28, wherein said providing means provides said respective paging messages for sending on the different carriers at substantially the same time .

30. Apparatus as claimed in any of claims 26 to 29, wherein said providing means provides said respective paging messages for sending on the different carriers at substantially different times .

31. Apparatus as claimed in claim 30, comprising providing a predetermined time, said predetermined time being such that said respective paging messages are offset by said predetermined time from a different one of said paging messages.

32. Apparatus as claimed in claim 31, wherein said predetermined time comprises an integer number of radio frames.

33. A base station comprising apparatus as claimed in any of claims 26 to 32.

34. Apparatus comprising means for monitoring one of a plurality of aggregated carriers for a paging message.

35. Apparatus as claimed in claim 34, wherein said means for monitoring is configured to monitor said carrier with an index based on an identity of a monitoring entity for said paging message .

36. A user equipment comprising apparatus as claimed in claim 34 or 35.

37. An integrated circuit or chip set comprising apparatus as claimed in any of claims 26 to 32, 34 or 35

38. A method comprising: formulating respective paging messages; sending via a transmission arrangement on each of a plurality of carriers, said plurality of carriers being aggregated together, said respective paging messages.