WO2014121518A1

WO2014121518A1 - Enhanced paging operation for power saving mode

Info

Publication number: WO2014121518A1
Application number: PCT/CN2013/071570
Authority: WO
Inventors: Chunyan Gao; Pengfei Sun; Na WEI; Lili Zhang; Wei Hong; Wei Bai; Haiming Wang; Jing HAN
Original assignee: Broadcom Corporation
Priority date: 2013-02-08
Filing date: 2013-02-08
Publication date: 2014-08-14

Abstract

The present invention relates to methods, apparatuses and a computer program product for an enhanced paging operation for power saving mode. The present invention includes receiving, at a user equipment, a signaling message from a base station, detecting, at the user equipment, that the base station, which has sent the signaling message, is in a sleeping mode based on the received signaling message, and adopting, by the user equipment, a predetermined paging operation, when it is detected that the base station is in the sleeping mode.

Description

ENHANCED PAGING OPERATION FOR POWER SAVING MODE

Field of the invention The present invention refates to an enhanced paging operation for power saving mode, and more particularly, relates to methods, apparatuses and a computer program product for an enhanced paging operation for power saving mode.

Background

The power consumption has always been carefully handled for UE in LTE standardization due to the limited power supplies. However, the power consumption on the network side was somehow less mentioned. The network is deemed as power sufficient and the focus was more on the network capacity and coverage. However, the situation is changing due to the fast increasing concern on the carbon footprint and the operator cost. Although the Information and Communication Technology (ICT) industry only accounts for a relatively small portion of the overall energy consumption of human being's activity, as described for example in document [1], it is imperative to make it more power efficient given the fact that the mobile communication sector is about to triple by the year 2020.

Current LTE eNBs must keep on transmitting DL signals no matter if there is any UE to serve. These signals include broadcast signals such as PSS/SSS/MIB and CRS. This mandatory transmission wastes a great amount of energy as the network is under low load most of the time (cf. document [2]). Significant power saving is possible if the future wireless networks could intelligently avoids these wastes. Standalone new carrier type (SA-NCT) is considered to be one of the important topics for Re!-12 enhancement, where new features are taken into account. A more power efficient lean carrier is proposed in document [3] to increase the power efficiency. Another use case is the local area network, where the cell size is considerably smaller than a typical macro cell. In this case the local area cell may serve only a few of UEs, sometimes there are even no UE served and the load may undergo large variance from time to time. Thus power saving could be achieved by accommodating this variance. In document [3], an uitra-Iean booster carrier concept is proposed, which is used in local area to boost network capacity but with enhanced interference minimization and energy efficiency.

Among those power efficiency techniques, sleeping mode is a very effective way to reduce power consumption during low network load condition (cf. document [2]), for example in the rural area solar powered eNB or the dense deployed local area eNBs. The eNB transmits minimum broadcast signal or totally turns off in the sleeping mode when needed to save power. There may be many ways to realize such an eNB sleeping mode and there may be different levels of sleeping to achieve different levels of power efficiency. Some kind of sleeping could be achieved with current 3GPP standards via the MBSFN subframes. An eNB configures MBSFN subframes when load is low and then eNB could turn off the radio frequency (RF) during these subframes to save power. In document [2], the cell DTX could further save the power compared to the MBSFN technique due to the reduced CRS and minimum broadcast signals. However, this sleeping mode may impact the UE behavior depending on how much the DL signal is reduced, then it must be evaluated which signals can be reduced and which has to be kept.

In NCT, there is the proposal to reduce or avoid CRS transmission, which makes it possible to totally turn off the RF in some subframes. In document [4], there are proposals to reduce the density of PSS/SSS/BCH which are also cell-common signaling.

However, there are still other common control signals that can be reduced to further save eNB power. According to current specification, the UE will detect paging only in paging subframes (PFs) which are UE-specific and one PF may contain one or multiple Paging Occasion(s). When DRX is used, the UE needs only to monitor one PO per DRX cycle.

According to document [5], the PF and PO is determined by following formulae using the DRX parameters provided in System Information :

• PF is given by following equation:

o SFN mod T= (T div N)*(UE_ID mod N)

• Index i_s pointing to PO from subframe pattern defined in section 7.2 in document [5] will be derived from following calculation :

o i_s = floor(UE_ID/N) mod Ns

According to document [5], the following Parameters are used for the calculation of the PF and Ls:

- T: DRX cycle of the UE; T is determined by the shortest of the UE specific DRX value, if allocated by upper layers, and a default DRX value broadcast in system information ; If UE specific DRX is not configured by upper layers, the default value is applied ;

- nB: 4T, 2T, T, T/2, T/4, T/8, T/16, T/32.

- N : min(T,nB)

- Ns: max(l,nB/T)

- UE_ID: IMSI mod 1024.

Due to the UEs-specific paging configuration which is determined by UE-ID and DRX configuration, paging for UEs can distribute in all DL subframes, though paging for one UE is only restricted to certain subframes. For a macro cell with large number of UEs, such design helps to balance the load in each subframe. However, in some scenarios, e.g., small cell with less number of UEs, this potentially reduces the chance for eNB power saving since it may need to send paging in any subframe.

Another example can be the eNB in sleeping mode. For this eNB, it may decide to wake up and exit the sleep mode only in case of data arrival for multiple UEs, rather than triggered by a need to send paging to a single UE. However, with current specification, the eNB has to wake up and send paging in all the UEs' Paging subframe, otherwise the UE cannot detect it. Then, obviously, this puts restriction to eNB operation and reduces the chance for power saving.

According to the present invention, there is proposed one solution to solve the problem and further improve eNB power saving without introducing more complexity at UE side.

Further, according to the present invention, it is proposed to introduce a new feature to sleeping mode network to further improve the power saving.

The proposals according to the present invention can work together with other solutions to get more gain.

References :

[1] Ericsson, "Carbon footprint of mobile communications and ICT"

[2] Ericsson, "Reducing Energy Consumption in LTE with Cell DTX"

[3] Ericsson, "Views on TD-LTE for Rel-12", presentation on CMCC TD-LTE workshop, Apr. 2012.

[4] Patent application No. PCT/CN 2012/080981

[5] 3GPP TS 36.304

Summary of the invention

According to exemplary aspects of the present invention, there are provided methods, apparatuses and a computer program product for an enhanced paging operation for power saving mode.

Various aspects of exemplary embodiments of the present invention are set out in the appended claims.

According to an exemplary aspect of the present invention, there is provided a method for use in a user equipment, comprising :

receiving, at a user equipment, a signaling message from a base station, detecting, at the user equipment, that the base station, which has sent the signaling message, is in a sleeping mode based on the received signaling message, and

adopting, by the user equipment, a predetermined paging operation, when it is detected that the base station is in the sleeping mode.

According to another exemplary aspect of the preent invention, there is provided a method for use in a base station, comprising :

transmitting, by a base station, a signaling message to one or more user equipments,

wherein the signaling message includes an indication for the user equipment to adopt a predetermined paging operation.

According to another exemplary aspect of the present invention, there is provided an apparatus, comprising :

at least one processor,

and at least one memory including computer program code,

the at least one memory and the computer program code arranged to, with the at least one processor, cause the apparatus at least to perform :

receiving a signaling message from a base station,

detecting that the base station, which has sent the signaling message, is in a sleeping mode based on the received signaling message, and

adopting a predetermined paging operation, when it is detected that the base station is in the sleeping mode.

at least one processor,

and at least one memory including computer program code,

transmitting a signaling message to one or more user equipments, wherein the signaling message includes an indication for the user equipment to adopt a predetermined paging operation. According to an exemplary aspect of the present invention, there is provided a computer program product comprising computer-executable computer program code which, when the program is run on a computer (e.g. a computer of an apparatus according to any one of the aforementioned apparatus-reiated exemplary aspects of the present invention), is arranged to cause the computer to carry out the method according to any one of the aforementioned method- related exemplary aspects of the present invention. Such computer program product may comprise or be embodied as a (tangible) computer-readable (storage) medium or the like on which the computer- executable computer program code is stored, and/or the program may be directly loadable into an internal memory of the computer or a processor thereof. Advantageous further developments or modifications of the aforementioned exemplary aspects of the present invention are set out in the dependent claims.

Brief Description of the Drawings For a more complete understanding of exemplary embodiments of the present invention, reference is now made to the following description taken in connection with the accompanying drawings in which :

Fig. 1(a) is a diagram illustrating current paging occasions;

Fig. 1(b) is a diagram illustrating paging occasions according to certain embodiments of the present invention;

Figs. 2(a) and (b) show diagrams illustrating an example of determining a RACH resource according certain embodiments of the present invention;

Fig. 3 shows a principle flowchart of an example for a method according to certain embodiments of the present invention; Fig. 4 shows a principle configuration of an example for an apparatus according to certain embodiments of the present invention;

Fig. 5 shows a principle flowchart of another example for a method according to certain embodiments of the present invention;

Fig. 6 shows a principle configuration of another example for an apparatus according to certain embodiments of the present invention. Description of exemplary embodiments

Exemplary aspects of the present invention will be described herein below. More specifically, exemplary aspects of the present are described hereinafter with reference to particular non-limiting examples and to what are presently considered to be conceivable embodiments of the present invention. A person skilled in the art will appreciate that the invention is by no means limited to these examples, and may be more broadly applied.

It is to be noted that the following description of the present invention and its embodiments mainly refers to specifications being used as non-limiting examples for certain exemplary network configurations and deployments. Namely, the present invention and its embodiments are mainly described in relation to 3GPP specifications being used as non-limiting examples for certain exemplary network configurations and deployments. In particular, a LTE/LTE-Advanced communication system is used as a non-limiting example for the applicability of thus described exemplary embodiments. As such, the description of exemplary embodiments given herein specifically refers to terminology which is directly related thereto. Such terminology is only used in the context of the presented non-limiting examples, and does naturally not limit the invention in any way, Rather, any other network configuration or system deployment, etc. may also be utilized as long as compliant with the features described herein. According to the present invention, there is proposed one solution to solve the above mentioned problems and to further improve eNB power saving without introducing more complexity at UE side. Further, according to the present invention, it is proposed to introduce a new feature to sleeping mode network to further improve the power saving.

It is noted that the proposals according to the present invention can work together with other solutions to get more gain.

In order to enable maximum eIMB power saving, according to certain embodiments of the present invention, the following is proposed :

According to a first embodiment, the UEs can be configured to adopt a special paging operation via explicit or implicit signaling, for example:

o eNB configures it via a common signaling, like MIB/SIBs;

o UEs assume such a special paging operation based on detection that eNB is now in sleeping mode, e.g,

■ When get sieep mode indication signaling from eNB, or ■ When detected special RS or other signal pattern specific for sleeping mode;

The special paging operation defines same paging occasions for UEs, where the paging subframe and paging occasions are independent of UE-ID (T SI), or both UE-ID and DRX configurations;

o As one example, PF and PO can be given by following equations:

■ SFN mod T = 0, where T is determined by the default paging cycle and UE-ID, and

■ Ns=4; i_s=0; Then it points to subframe 0;

o In another example, the eNB can configure the cell-specific paging subframe to align with PDCH (or PSS/SSS transmission) to reduce power for eNB; According to a second embodiment, once the above described specially configured paging signal is detected, an UE that is a target UEs of this paging, will consider it as normal paging (indication of data arrival or system information change), and at the same time consider it as one indication showing that eNB exits sleep mode. Then, the UEs will perform the following:

In case there is need to switch to connected mode (data arrival), the UEs derive the resource/time to send RACH based on the PagingRecord-ID in the paging message to avoid/reduce collision. Further, the UE adjust some of its operation based on the mode switch.

For a UE which is not target UE of this paging, it will only consider it as one indication showing that eNB exits sleep mode, then it may adjust its operation based on the mode change.

It is noted that the first embodiment can work alone or can work together with the second embodiment. In the following, there are some examples to show how certain embodiments of the present invention are implemented. Fig. 1(a) shows one example of paging occasions for a plurality of UEs 1, 2, 3, 4 respectively, which are determined by their DRX configuration and UE-ID. In the present example, 4 UEs are illustrated. However, it should be evident that the number of UEs is of course not limited to any specific number. In the example shown in Fig. 1(a), the UE has to detect the paging in a defined subframe, even if it is in DRX, then it is not good from power saving point of view.

And from eNB side, it has to send multiple paging in multiple subframes to inform the system information change. In Fig. 1(b), it is assumed that UEs are configured to adopt cell-specific paging occasion. The paging occasion is aligned with PSS/SSS transmission, thus, UEs only need to detect in one subframe for SCH detection and paging detection purpose, and it allows more subframes to DRX. From eNB side, it helps to avoid multiple transmissions and then to save power. In case, one UE being paged needs to switch to connected mode, then it will send RACH first. Since there can be multiple UEs being paged in same subframe, it is proposed to determine the UE RACH resource based on the position of its PagingRecord in the Paging record list to avoid RACH collision. Such an example is illustrated in Figs. 2(a) and (b).

Figs. 2(a) and (b) show an example of determining the RACH resource on the basis of the PagingRecord. As shown in Fig. 2(a), based on the PagingRecord, a preamble ID is allocated. For example, for the first PagingRecord#l in the paging record list, the preamble ID #1 is allocated. Further, as shown in Fig. 2(b), based on the PagingRecord, a back off time is allocated. That is, for example, for the first PagingRecord#l in the paging record list, a back off time = T is allocated. As a further example, for the second first PagingRecord#2 in the paging record list, the preamble ID #2 and a back off time = 2T is allocated, and so on.

In another example, it is assumed that the UEs adopt the special paging operation when eNB enters the sleeping mode. The mode of the eNB can be known based on detection of indication signaling or detection of specific RS/signaling pattern. Once such special paging operation is adopted, the eNB can decide whether to wake up and exit the sleep mode based on traffic. For example, when there is data for multiple UEs, it decides to wake up. In such case, it only needs to send one paging message in the configured position and all UEs will detect it.

For UEs whose IDs are indicated in paging record, they will see it as a normal paging and send RACH to transfer to connected mode, and the RACH resource can be derived based on the method mentioned above, and at the same time it can see it as one indication that eNB now is back to normal mode, then in the following it will assume normal PSS/SSS and RS pattern for detection and measurement.

For UEs whose IDs are not indicated in paging record, they will see it as one indication that eNB now is back to normal mode, then they will adjust their measurement accordingly in case there is different measurement defined for each eNB operation mode.

Thus, the proposed special paging operation can be applied to both normal and sleep mode of the network. In case it is used in sleep mode, it serves both as a paging and a signaling for eNB wake up.

In view of the above, the present invention according to certain embodiments can improve power efficiency of user equipments and base stations, like, e.g. eNBs in LTE.

Fig. 3 shows a principle flowchart of an example for a method according to certain embodiments of the present invention. That is, as shown in Fig. 3, this method comprises receiving, at a user equipment, a signaling message from a base station in a step S31, and detecting, at the user equipment, that the base station, which has sent the signaling message, is in a sleeping mode based on the received signaling message, in a step S32. Then, in a step S33, the user equipment adopts a predetermined paging operation, when it is detected that the base station is in the sleeping mode.

According to exemplary embodiments of the present invention, the signaling message includes a sleep mode indication that indicates the sleep mode of the base station, or the signaling message includes a predetermined reference signal or signal pattern indicating the sleep mode of the base station.

According to further exemplary embodiments of the present invention, the predetermined paging operation defines a paging subframe and a paging occasion for the user equipment that are independent from the identification of the user equipment and the discontinuous reception configuration of the user equipment, and the predetermined paging operation may define a paging subframe and a paging occasion that align with a synchronization channel and/or a discovery channel. According to exemplary embodiments of the present invention, the method further comprises receiving, at the user equipment, a paging signal according to the predetermined paging operation, determining, at the user equipment, whether the user equipment is a target of the paging signal, and if it is determined that the user equipment is a target of the paging signal, considering the paging signal as indication of data arrival or system information change and as an indication that the base station exits a sleeping mode.

According to exemplary embodiments of the present invention, if the paging signal is considered as data arrival, the user equipment derives the resource/time to send a random access channel, RACH, based on a paging record identification included in the paging signal, and switches to a connected mode.

According to exemplary embodiments of the present invention, if it is determined that the user equipment is not a target of the paging signal, the user equipment considers the paging signal as an indication that the base station exits a sleeping mode and adjusting its operation, wherein adjusting its operation includes stopping using the predetermined paging configuration, and switching to a user equipment specific paging operation, which is being configured.

Fig. 4 shows a principle configuration of an example for a user equipment according to certain embodiments of the present invention. One option for implementing this example for a user equipment according to certain embodiments of the present invention would be a component in a handset such as user equipment UE according to LTE/LTE-A. For example, the user equipment may be a mobile phone, a personal digital assistant (PDA), a laptop computer, a tablet computer, or the like.

Specifically, as shown in Fig. 4, the example for a user equipment 40 comprises at least one processor 41, at least one memory 42 including computer program code and an interface 43 which are connected by a bus 44 or the like. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the user equipment at least to perform receiving a signaling message from a base station, detecting that the base station, which has sent the signaling message, is in a sleeping mode based on the received signaling message, and adopting a predetermined paging operation, when it is detected that the base station is in the sleeping mode. For further functions of the user equipment according to further exemplary embodiments of the present invention, reference is made to the above description of a method according to certain embodiments of the present invention, as described in connection with Fig . 3. Fig. 5 shows a principle flowchart of another example for a method according to certain embodiments of the present invention. That is, as shown in Fig. 5, this method comprises transmitting, by a base station, a signaling message to one or more user equipments in a step S51, wherein the signaling message includes an indication for the user equipment to adopt a predetermined paging operation.

According to exemplary embodiments of the present invention the signaling message includes a predetermined reference signal or signal pattern indicating the sleep mode of the base station, or the signaling message includes a sleep mode indication that indicates the base station is in sleep mode, and the predetermined paging operation defines a paging subframe and a paging occasion for the user equipment that are independent from the identification of the user equipment and the discontinuous reception configuration of the user equipment. Further, the predetermined paging operation may define a paging subframe and a paging occasion that align with a synchronization channel and/or a discovery channel.

Fig. 6 shows a principle configuration of another example for an apparatus according to certain embodiments of the present invention. One option for implementing this example for an apparatus according to certain embodiments of the present invention would be a base station like an eNB according to LTE/LTE-A. Specifically, as shown in Fig. 6, the example for an apparatus 60, e.g. a base station or an eNB, comprises at least one processor 61, at least one memory 62 including computer program code, and an interface 63 which are connected by a bus 64 or the like. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus at least to perform transmitting a signaling message to one or more user equipments wherein the signaling message includes an indication for the user equipment to adopt a predetermined paging operation. For further functions of the base station / eNB according to further exemplary embodiments of the present invention, reference is made to the above description of a method according to certain embodiments of the present invention, as described in connection with Fig . 5. In the foregoing exemplary description of the apparatus, i.e. the user equipment and base station, only the units that are relevant for understanding the principles of the invention have been described using functional blocks. The apparatus may comprise further units that are necessary for its respective operation as user equipment and base station, respectively. However, a description of these units is omitted in this specification. The arrangement of the functional blocks of the apparatuses is not construed to limit the invention, and the functions may be performed by one block or further split into sub-blocks. Further, the apparatus, i.e. the user equipment or the base station, may be connected via a link 45/65. The link 45/65 may be a physical and/or logical coupling, which is implementation-independent (e.g. wired or wireless).

According to exemplarily embodiments of the present invention, a system may comprise any conceivable combination of the thus depicted devices/apparatuses and other network elements, which are arranged to cooperate as described above.

In general, it is to be noted that respective functional blocks or elements according to above-described aspects can be implemented by any known means, either in hardware and/or software, respectively, if it is only adapted to perform the described functions of the respective parts. The mentioned method steps can be realized in individual functional blocks or by individual devices, or one or more of the method steps can be realized in a single functional block or by a single device.

Generally, any procedural step or functionality is suitable to be implemented as software or by hardware without changing the idea of the present invention. Such software may be software code independent and can be specified using any known or future developed programming language, such as e.g. Java, C++, C, and Assembler, as long as the functionality defined by the method steps is preserved. Such hardware may be hardware type independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-Transistor Logic), etc., using for example ASIC (Application Specific IC (Integrated Circuit)) components, FPGA (Field-programmable Gate Arrays) components, CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components. A device/apparatus may be represented by a semiconductor chip, a chipset, system in package (SIP), or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device/apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code portions for execution/being run on a processor. A device may be regarded as a device/apparatus or as an assembly of more than one device/apparatus, whether functionally in cooperation with each other or functionally independently of each other but in a same device housing, for example. Apparatuses and/or means or parts thereof can be implemented as individual devices, but this does not exclude that they may be implemented in a distributed fashion throughout the system, as long as the functionality of the device is preserved. Such and similar principles are to be considered as known to a skilled person. Software in the sense of the present description comprises software code as such comprising code means or portions or a computer program or a computer program product for performing the respective functions, as well as software (or a computer program or a computer program product) embodied on a tangible medium such as a computer-readable (storage) medium having stored thereon a respective data structure or code means/portions or embodied in a signal or in a chip, potentially during processing thereof. The present invention also covers any conceivable combination of method steps and operations described above, and any conceivable combination of nodes, apparatuses, modules or elements described above, as long as the above- described concepts of methodology and structural arrangement are applicable. That is, for example, it is possible to perform the above mentioned timing advance procedure and the connectivity adjustment procedure either individually or in combination.

Even though the present invention and/or exemplary embodiments are described above with reference to the examples according to the accompanying drawings, it is to be understood that they are not restricted thereto. Rather, it is apparent to those skilled in the art that the present invention can be modified in many ways without departing from the scope of the inventive idea as disclosed herein.

Abbreviations:

ACK Acknowledgement

BCH Broadcast Channel

CE control element

CRS Cell-specfic Reference Signal

CSI Channel State Information

DL Downlink

DRX Discontinuous Reception

DTX Discontinuous transmission

eNB Enhanced Node B HARQ Hybrid Automatic Repeat reQuest

ICT Information Communications Technology

LTE Long Term Evolution

LTE-A Long Term Evolution Advanced

MAC Medium Access Control

MBSFN Multimedia Broadcast Single Frequency Network

MIB Master Information Block

NCT New Carrier Type

PDCCH Physical Downlink Control Channel

PF Paging Frame

PO Paging Occasion

PUCCH Physical Uplink Control Channel

PSS Primary Synchronization Signal

RA Random Access

RACH Random Access Channel

RRC Radio Resource Control

SCH Synchronization Channel

SFN SubFrame Number

SPS Semi-Persistent Scheduling

SR Scheduling Request

SRS Sounding Reference Signal

SSS Secondary Synchronization Signal

TA Timing Advance

TAT TA Timer

TMSI Temporary Mobile Subscriber Identification

UE User Equipment

UL Uplink

Claims

WHAT IS CLAIMED IS:

1. A method for use in a user equipment, comprising :

2. The method according to claim 1, wherein

the signaling message includes a sleep mode indication that indicates the sleep mode of the base station.

3. The method according to claim 1, wherein

the signaling message includes a predetermined reference signal or signal pattern indicating the sleep mode of the base station.

4. The method according to any one of claims 1 to 3, wherein

the predetermined paging operation defines a paging subframe and a paging occasion for the user equipment that are independent from the identification of the user equipment and the discontinuous reception configuration of the user equipment.

5. The method according to claim 4, wherein the predetermined paging operation defines a paging subframe and a paging occasion that align with a synchronization channel and/or a discovery channel.

6. The method according to any one of claims 1 to 4, further comprising

receiving, at the user equipment, a paging signal according to the predetermined paging operation,

determining, at the user equipment, whether the user equipment is a target of the paging signal, and if it is determined that the user equipment is a target of the paging signal, considering the paging signal as indication of data arrival or system information change and as an indication that the base station exits a sleeping mode.

7. The method according to claim 6, wherein

if the paging signal is considered as data arrival,

deriving the resource/time to send a random access channel, RACH, based on a paging record identification included in the paging signal, and

switching to a connected mode.

8. The method according to claim 6, wherein

if it is determined that the user equipment is not a target of the paging signal, considering the paging signal as an indication that the base station exits a sleeping mode and adjusting its operation.

9. The method according to claim 8, wherein

adjusting its operation includes stopping using the predetermined paging configuration, and switching to a user equipment specific paging operation, which is being configured.

10. The method according to any one of claims 1 to 9, wherein the method is implemented in a user equipment located in a Long Term Evolution or Long Term Evolution Advanced based cellular communication network.

11. A method for use in a base station, comprising :

12. The method according to claim 11, wherein

13. The method according to claim 11, wherein

the signaling message includes a sleep mode indication that indicates the base station is in sleep mode.

14. The method according to claim 11, wherein

15. The method according to claim 11, wherein

the predetermined paging operation defines a paging subframe and a paging occasion that align with a synchronization channel and/or a discovery channel.

16. The method according to any one of claims 11 to 15, wherein the method is implemented in a base station located in a Long Term Evolution or Long Term Evolution Advanced based cellular communication network.

17. An apparatus for use in a user equipment, comprising :

at least one processor,

and at least one memory including computer program code,

receiving a signaling message from a base station,

18. The apparatus according to claim 17, wherein

19. The apparatus according to claim 17, wherein

20. The apparatus according to any one of claims 17 to 19, wherein

21. The apparatus according to claim 20, wherein the predetermined paging operation defines a paging subframe and a paging occasion that align with a synchronization channel and/or a discovery channel.

22. The apparatus according to any one of claims 17 to 20, further comprising receiving a paging signal according to the predetermined paging operation, determining whether the user equipment is a target of the paging signal, and

if it is determined that the user equipment is a target of the paging signal, considering the paging signal as indication of data arrival or system information change and as an indication that the base station exits a sleeping mode.

23. The apparatus according to claim 22, wherein

if the paging signal is considered as data arrival,

switching to a connected mode.

24. The apparatus according to claim 22, wherein

25. The apparatus according to claim 24, wherein adjusting its operation includes stopping using the predetermined paging configuration, and switching to a user equipment specific paging operation, which is being configured.

26. The apparatus according to any one of claims 17 to 25, wherein the apparatus is implemented in a user equipment located in a Long Term Evolution or Long Term Evolution Advanced based cellular communication network.

27. An apparatus for use in a base station, comprising :

at least one processor,

and at least one memory including computer program code,

transmitting a signaling message to one or more user equipments, wherein the signaling message includes an indication for the user equipment to adopt a predetermined paging operation.

28. The apparatus according to claim 27, wherein

29. The method according to claim 27, wherein

30. The apparatus according to claim 27, wherein

31. The apparatus according to claim 27, wherein the predetermined paging operation defines a paging subframe and a paging occasion that align with a synchronization channel and/or a discovery channel.

32. The apparatus according to any one of claims 27 to 31, wherein the apparatus is implemented in a base station located in a Long Term Evolution or Long Term Evolution Advanced based cellular communication network.

33. An apparatus, comprising :

means for receiving a signaling message from a base station,

means for detecting that the base station, which has sent the signaling message, is in a sleeping mode based on the received signaling message, and means for adopting a predetermined paging operation, when it is detected that the base station is in the sleeping mode.

34. An apparatus, comprising :

means for transmitting a signaling message to one or more user equipments,

35. A computer program product comprising computer-executable computer program code which, when the program is run on a computer, is arranged to cause the computer to carry out the method according to any one of claims 1 to 16.

36. The computer program product according to claim 35, embodied as a computer-readable storage medium.