WO2015063591A2

WO2015063591A2 - Method and apparatus for setting a drx configuration in dual connectivity communication systems

Info

Publication number: WO2015063591A2
Application number: PCT/IB2014/002612
Authority: WO
Inventors: Yun DENG; Chandrika Worrall
Original assignee: Alcatel Lucent
Priority date: 2013-11-01
Filing date: 2014-10-27
Publication date: 2015-05-07
Also published as: CN104602259B; CN104602259A; WO2015063591A3

Abstract

The invention describes a method and apparatus for setting a DRX configuration in dual connectivity communication systems. A MeNB determines a DRX cycle length of a macro cell according to the measurement requirement and characteristics of the traffic data. A SeNB determines a DRX cycle length of a small cell according to characteristics of the traffic data. A user equipment may have the same or different cycle length in the macro cell and in the small cell. The MeNB and SeNB determine its own DRX cycle length via negotiation, and transmit the DRX cycle length information for determining measurement requirement to user equipment. The SeNB determines a serving small cell suitable to user equipment, or coordinates the interference between small cells according to the measurement report from the MeNB.

Description

Method and apparatus for setting a DRX configuration in dual connectivity communication systems

Field of the invention

The present application relates to LTE communications, and particularly to a Discontinuous Reception (DRX) configuration in LTE communications.

Background of the invention

Small cell as an important supplement to Long Term Evolution (LTE key infrastructure, mainly adopted for enhancing the capacity and coverage of a local area, especially due to its characteristics of low power consumption, has been attracted a lot of interest in the industry. In 3 GPP R12, one new study item "Small Cell Enhancements for E-UTRA and E-UTRAN Higher-Layer Aspects" has been approved. One important aspect of this study item is to support the user equipment's dual connectivity with a macro cell and a small cell. In RAN2#83bis meeting, the working assumption of supporting different DRX configuration (DRX configuration includes DRX cycle length, DRX starting time etc.) for Master eNB (MeNB) and Secondary eNB (SeNB) is achieved. According to TS36.133, measurement requirement depends on DRX configuration (e.g. DRX cycle length). For example, when a DRX is not configured, in RRC_CONNECTED state, intra-frequency measurement cycle is 200 milliseconds, a User Equipment (UE) should be able to perform Reference Signal Receiving Qualities (RSRQ) and Reference Signal Receiving Powers (RSRP) measurement for 8 intra-frequency cells, and meanwhile the user equipment must be able to report the measurement result from physical layer to high layer in a measurement period of 200ms; when a DRX is configured, the measurement requirement is associated with the DRX cycle length. When a DRX cycle length is configured independently in a MeNB and a SeNB, a UE may have two different DRX cycle lengths, thus the UE may have different understanding on which DRX cycle length should be adopted to perform frequency measurement. Therefore, how to determine an unambiguous DRX cycle length to meet the measurement requirement from a UE is essential.

Summary of the invention

The method disclosed in the present application mainly solves the problem of an ambiguous DRX cycle length, which is used to determine the measurement requirement, caused by the different DRX configurations in a MeNB and a SeNB.

According to a first aspect of the present application, there provides a method, in a MeNB, for performing a DRX configuration for a dual connectivity system, the method comprising: transmitting, to a SeNB, a DRX cycle length of a macro cell associated with the dual connectivity system ; obtaining, from the SeNB, DRX configuration information of a small cell associated with the dual connectivity system; transmitting, to a user equipment, a DRX configuration of the macro cell and a DRX configuration of a small cell; transmitting, to the SeNB, a measurement report associated with a frequency measurement of a small cell according to a measurement report from the user equipment.

According to a second aspect of the present application, there provides a method, in a SeNB, for performing a DRX configuration for a dual connectivity system, the method comprising: obtaining DRX cycle length information of a macro cell from a MeNB; transmitting, to a MeNB, a DRX configuration of a small cell that is determined according to the DRX cycle length information from the MeNB; receiving a measurement report associated with frequency of a small cell from the MeNB; determining a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report from the MeNB.

According to a third aspect of the present application, there provides a method, in a MeNB, for performing a DRX configuration for a dual connectivity system , the method comprising: transmitting, to a user equipment, a DRX cycle length for determining a measurement requirement; obtaining, from a SeNB, DRX configuration information of a small cell associated with the dual connectivity system; transmitting, to the user equipment, DRX configuration information of a macro cell and DRX configuration of a small cell associated with the dual connectivity system; transmitting a measurement report associated with frequency measurement of a small cell to the SeNB according to the measurement report from the user equipment.

According to a fourth aspect of the present application, there provides a method, in a SeNB, for performing a DRX configuration for a dual connectivity system, the method comprising: transmitting DRX configuration information of a small cell to a MeNB ; receiving a measurement report associated with frequency of a small cell from a MeNB; determining a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report from the MeNB.

According to a fifth aspect of the present application, there provides a method, in a MeNB, for performing a DRX configuration for a dual connectivity system, the method comprising: obtaining, from a SeNB, DRX configuration information of a small cell associated with a dual connectivity system; transmitting, to a user equipment, a DRX configuration of a small cell and a DRX configuration of a macro cell associated with the dual connectivity system; transmitting a measurement report associated with frequency measurement of a small cell to the SeNB according to a measurement report from the user equipment.

According to a sixth aspect of the present application, there provides a method, in a SeNB, for performing a DRX configuration for a dual connectivity system, the method comprising: determining that DRX configuration information of a macro cell is not received from a MeNB for a period of time; transmitting, to a MeNB, DRX configuration information of a small cell determined according to characteristics of traffic data of a SeNB; receiving a measurement report associated with frequency of a small cell from a MeNB; determining a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report from the MeNB.

According to a seventh aspect of the present application, there provides a method, in a user equipment, for performing a DRX configuration for a dual connectivity system, the method comprising: obtaining DRX configuration information associated with a dual connectivity system from a MeNB; transmitting a measurement report, measured according to frequency measurement requirement corresponding to the determined DRX cycle length, to the MeNB.

According to a eighth aspect of the present application, there provides a method, in a user equipment, for performing a DRX configuration for a dual connectivity system, the method comprising: obtaining, from a MeNB, DRX configuration information associated with a dual connectivity system; obtaining, from a MeNB, DRX cycle length information for determining a measurement requirement; transmitting, to the MeNB, a measurement report measured according to frequency measurement requirement corresponding to the determined DRX cycle length.

According to a ninth aspect of the present application, there provides an apparatus, in a MeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a transmitting unit configured to transmit, to a SeNB, DRX cycle length information of a macro cell associated with a dual connectivity system, to transmit, to the user equipment, a DRX configuration of the macro cell and a DRX configuration of a small cell associated with the dual connectivity system, and to transmit a measurement report associated with frequency measurement of a small to the SeNB based on the measurement report from the equipment; a receiving unit configured to obtain, from the SeNB, a DRX configuration information of the small cell associated with a dual connectivity system.

According to a tenth aspect of the present application, there provides an apparatus, in a SeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a transmitting unit configured to transmit a DRX configuration of a small cell, determined according to DRX cycle length information from a MeNB, to the MeNB; a receiving unit configured to obtain a measurement report associated with frequency of a small cell from the MeNB and to obtain DRX cycle length information of a macro cell from the MeNB; a determining unit configured to determine a serving small cell suitable to a user equipment or coordinate interference between small cells according to the measurement report from the MeNB.

According to a eleventh aspect of the present application, there provides an apparatus, in a MeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a transmitting unit configured to transmit, to a user equipment, a DRX cycle length for determining a measurement requirement, to transmit, to the user equipment, DRX configuration information of a macro cell and DRX configuration information of a small cell associated with the dual connectivity system, and to transmit a measurement report associated with frequency measurement of a small cell to the SeNB based on a measurement report from the user equipment; a receiving unit configured to obtain, from the SeNB, DRX configuration information of the small cell associated with the dual connectivity system.

According to a twelfth aspect of the present application, there provides an apparatus, in a SeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a transmitting unit configured to transmit, to a MeNB, DRX configuration information of a small cell determined according to characteristics of traffic data of a SeNB; a receiving unit configured to receive a measurement report associated with frequency of a small cell from a MeNB; a determining unit configured to determine a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report from the MeNB, and to determine that DRX configuration information of a macro cell is not received from a MeNB for a period of time.

According to a thirteenth aspect of the present application, there provides an apparatus, in a MeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a receiving unit configured to obtain, from a SeNB, DRX configuration information of a small cell associated with a dual connectivity system; a transmitting unit configured to transmit, to the user equipment, a DRX configuration of a small cell and a DRX configuration of the macro cell associated with a dual connectivity system, and to transmit a measurement report associated with frequency measurement of a small cell to the SeNB according to a measurement report from the user equipment.

According to a fourteenth aspect of the present application, there provides an apparatus, in a SeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a transmitting unit configured to transmit DRX configuration information of a small cell to a MeNB; a receiving unit configured to receive a measurement report associated with frequency of a small cell from a MeNB; a determining unit configured to determine a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report for the MeNB, and to determine that DRX configuration information of a macro cell is not received from a MeNB for a period of time.

According to a fifteen aspect of the present application, there provides an apparatus, in a user equipment, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a transmitting unit configured to transmit, to the MeNB, a measurement report measured according to frequency measurement requirement corresponding to the determined DRX cycle length; a receiving unit configured to obtain the DRX configuration information associated with a dual connectivity system from a MeNB.

According to a sixteenth aspect of the present application, there provides an apparatus, in a user equipment, for performing a DRX configuration for a dual connectivity system, the apparatus comprising: a transmitting unit configured to transmit, to the MeNB, a measurement report measured according to frequency measurement requirement corresponding to the determined DRX cycle length; a receiving unit configured to obtain, from a MeNB, DRX cycle length information for determining measurement requirement, and to obtain DRX configuration information associated with a dual connectivity system from a MeNB.

The solution in the present application not only enables a UE to have an unambiguous DRX cycle to meet the measurement requirement, but also enables a SeNB to determine a serving small cell suitable to a UE or coordinate the interference between small cells.

Brief description of drawings

Through the following detailed descriptions of embodiments of the present application given by below drawings, the invention will be understood better, and the objects, details, features and advantageous of the present invention will become more apparent.

Figure 1 illustrates a schematic view of a UE having a dual-connectivity with a macro cell and a small cell.

Figure 2 illustrates a flow chart of setting the same DRX cycle length in a macro cell and in a small cell.

Figure 3 illustrate another flow chart of setting the same DRX cycle length in a macro cell and in a small cell.

Figure 4 illustrates a flow chart of setting different DRX cycle length in a macro cell and in a small cell.

Throughout the above drawings, same or similar reference numerals will be understood to refer to same or similar step features/apparatus (module).

Detailed description of embodiments

In detailed description of the preferred embodiment hereafter, appended figures, as part of the present application, will be referred. The appended drawings illustrate the specific embodiments to carry out the present application through exemplary manner. Exemplary embodiments are not intended to exhaust all embodiments of the present application. It needs to clarify that, although steps associated with corresponding method in the present application is described in a specific order in accompanying drawings, it does not requires or suggests that those operations must be performed accordance with the specific order, or all the illustrated operations must be performed in order to achieve the desired results, in contrast, the order described in the present application can be changed. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and/or one step may be decomposed into several steps.

Figure 1 illustrates an embodiment of a dual-connectivity communication system. As illustrated in Figure 1 , a UE accesses a macro cell and establishes Radio Resource Controller (RRC) connection with the macro cell. When a MeNB finds that there is a small cell to offload traffic data for a UE, the macro cell can configure a dual connectivity for the UE, i.e., the UE may connect to the macro cell and the small cell simultaneously. The MeNB and SeNB perform independent resource scheduling in respective own cells. An appropriate DRX configuration depends on the mobility of the UE, types of traffic data etc. As the UE may have different data radio bearers in a macro cell and in a small cell, DRX configurations constructed by the MeNB and the SeNB may not be the same. Thus, the MeNB and the SeNB need to configure a common DRX cycle length in order to meet the requirement of the frequency measurement.

The DRX cycle length of a UE in a macro cell and in a small cell may be the same, may also be different. Hereafter the description is based on whether the DRX cycle length is the same in the macro cell and in the small cell.

When a DRX cycle length of a UE in the macro cell is the same as a DRX cycle length in the small cell, the SeNB performs resource scheduling with the DRX cycle length for the UE in the small cell, and the scheduling needs to meet the characteristics of the data traffic. Because MeNB performs DRX configurations according to e.g. the measurement requirement and characteristics of the data traffic while SeNB performs DRX configuration only according to e.g. characteristics of the data traffic, the DRX cycle length for a UE in the macro cell might be different from its DRX cycle length in the small cell, therefore, MeNB and SeNB needs to determine a consistent DRX cycle length through a negotiation which can be carried out via X2 interface, and the information exchange via X2 may be based on, for example, 3GPP TS36.423, may also be based on any other feasible manner for information exchange. The characteristics of traffic data may be video streaming, VoIP, FTP downloading, etc. in respect to different Quality of Services (QoS).

In Step S I 00, MeNB 10 determines a DRX configuration of a macro cell for UE30 according to the measurement requirement and characteristics of the traffic data of UE30 in the macro cell, the DRX configuration of the macro cell includes DRX cycle length, DRX starting time etc. For simplicity, a DRX configuration of a UE in a macro cell refers to DRX configuration of a macro cell hereafter.

In Step S200, SeNB20 determines a DRX configuration of UE30 in a small cell according to the characteristics of the traffic data of UE30 in the small cell. For simplicity, DRX configuration of a UE in a small cell refers to DRX configuration of a small cell hereafter.

In Step S300, MeNB lO transmits the DRX cycle length of MeNB lO to SeNB20.

In Step S400, if SeNB20 accepts the DRX cycle length of MeNB lO transmitted by MeNB lO, SeNB20 transmits the DRX configuration of the small cell, configured according to DRX cycle length configured by MeNB lO and traffic characteristics of UE, to MeNB lO.

In Step S400B, if SeNB20 does not accept the DRX cycle length of MeNB lO transmitted by MeNB lO, SeNB20 transmits, to MeNB lO, a DRX configuration (including DRX cycle length) of a small cell configured according to traffic characteristics of UE. MeNB lO selects one from the DRX cycle length of the macro cell and the DRX cycle length of the small cell and transmits it to SeNB20. If the DRX cycle length of the small cell is selected, it is not necessary for SeNB20 to re-transmit the DRX configuration of the small cell to MeNB lO; if the DRX cycle length of the macro cell is selected, it is necessary for SeNB20 to transmit the DRX configuration of the small cell, which is configured according to the DRX length of the macro cell, to MeNB lO.

In Step S500, MeNB lO transmits the DRX configuration of the macro cell and the DRX configuration of the small cell to UE. In such a situation, the DRX configuration of the macro cell and small cell is the same. MeNB lO may transmit the DRX configuration to UE via RRC signaling or any other feasible manner.

In Step S600, UE30 performs measurement and transmits measurement report to MeNB lO. Because the DRX cycle length is the same, UE30 performs the measurement according to the frequency measurement requirement corresponding to the DRX cycle length, and reports the measurement report to MeNB lO when the reporting conditions are met.

In Step S700, MeNB lO transmits the measurement report associated with the frequency measurement of the small cell to SeNB20, i.e., transmits the measurement report of the frequency of the small cell to SeNB20.

In Step S800, SeNB20 determines whether the small cell is suitable to act as serving cell for UE30, or coordinates the interference between small cells according to the measurement report from MeNB lO.

Figure 3 illustrate another flow chart of setting a same DRX cycle length in a macro cell and in a small cell.

In Step B 100, SeNB20 does not receive a DRX configuration of a macro cell transmitted by MeNB lO for a period of time, this implies that MeNB lO has not configured a DRX configuration of macro cell yet. The period of time may be pre-configured via network.

In Step B200, SeNB20 determines the DRX configuration of the small cell according to characteristics of the traffic data of the small cell.

In Step B300, SeNB20 transmits the DRX configuration of the small cell (including DRX cycle length) to MeNB lO.

In Step B400, MeNB lO receives the DRX configuration of the small cell, which may act as the DRX configuration of the macro cell, and transmits the DRX configuration of the macro cell and the DRX configuration of the small cell to UE30. MeNB lO may transmit the DRX configuration to UE 30 via RRC signaling or any other feasible manner.

In Step B500, UE30 performs measurement and transmits measurement report to MeNB lO. Because the DRX cycle length is the same, UE30 performs measurement according to frequency measurement requirement corresponding to the DRX cycle length, and reports the measurement report to MeNB lO when the reporting conditions are met.

In Step B600, MeNB lO transmits the measurement report associated with the frequency measurement of the small cell to SeNB20, i.e., transmits the measurement report of the frequency of the small cell to SeNB20.

In Step B700, SeNB20 determines whether the small cell is suitable to act as serving cell for UE30, or coordinates the interference between small cells according to the measurement report from MeNB lO.

As the information for determining DRX in a macro cell and in a small cell is different, the DRX cycle length of the macro cell and the DRX cycle length of the small cell for UE30 may also be different. When the DRX cycle length of the macro cell and the DRX cycle length of the small cell for UE30 are different, it is necessary for MeNB lO to indicate UE30 to determine the measurement requirement according to the DRX cycle length of the macro cell or according to the DRX cycle length of the small cell; or adopt a predefined manner to perform the measurement, e.g., adopting the measurement requirement corresponding to the DRX cycle length of the macro cell, if MeNB lO does not have a DRX cycle length configured for the UE, UE30 performs the measurement according to the measurement requirement corresponding to no DRX configuration. The signaling exchange associated with the dual connectivity between MeNB lO and SeNB lO may be carried out via X2 interface, the signaling exchange via X2 interface may be based on 3GPP TS36.413, may be based on any other feasible signaling exchange manner.

Figure 4 illustrates a flow chart of configuring different DRX cycle lengths in a macro cell and in a small cell.

In Step Ml 00, MeNB lO determines a DRX configuration of the macro cell according to measurement requirement and characteristics of traffic data of UE30 in the macro cell.

In Step M200, SeNB20 determines a DRX configuration of the small cell according to characteristics of traffic data of UE30 in the small cell.

In Step M300, SeNB20 transmits the DRX configuration of the small cell to MeNB lO.

In Step M400, MeNB lO transmits the DRX configuration of the macro cell and the DRX configuration of the small cell to UE30. MeNB lO may transmit the DRX configuration to UE 30 via RRC signaling or any other feasible manner.

In Step M500, MeNB lO transmits the DRX cycle length indication information corresponding to measurement requirement to UE30.

In Step M600, UE30 performs the measurement according to the measurement requirement corresponding to the DRX cycle length indicated in Step M500, and transmits the measurement report to MeNB lO when the reporting conditions are met.

In Step M700, MeNB lO transmits the measurement report associated with the frequency measurement of the small cell to SeNB20, i.e., transmits the measurement report to SeNB20.

In Step M800, SeNB20 determines whether the small cell is suitable to continuously act as serving cell of UE30, or coordinates the interference between small cells according to the measurement report from the MeNB.

Step M500 in the procedure may be combined with Step M400 for transmission. MeNB lO may adopt a protocol pre-defined manner to determine the DRX cycle length corresponding to the measurement requirement. For example, it is pre-defined to adopt measurement requirement corresponding to DRX cycle length of macro cell for performing measurement, or it is predefined to adopt measurement requirement corresponding to DRX cycle length of small cell for performing measurement. As such, it is necessary for MeNB lO to transmit the predefined DRX cycle length information corresponding to measurement requirement to UE30. MeNB lO may transmit DRX cycle length information to UE30 via RRC signaling or any other feasible manner.

The DRX configuration as described above includes multiple parameters, for example, DRX cycle length, the starting time of DRX and duration period of DRX etc.

In addition, according to the current specification, RRC connection is available only between MeNBO and UE30, thus the measurement report regarding on frequency is transmitted from UE30 to MeNB lO. But SeNB20 also needs to obtain the measurement report to determine a serving cell suitable to UE30, or to perform interference co-ordination between serving cells, or to select other carrier with the same coverage area for UE30 and the other carrier is a small cell controlled by SeNB20. Therefore, MeNB lO transmits a part of the measurement report to SeNB20 via X2 interface. The part of the measurement report includes cell identification and corresponding RSRP and RSRQ, it may include other relevant measurement information.

The invention is herein described, with the reference to the accompanying drawing(s). However, it is appreciated that that the order of steps shown in accompanying drawings and described in specification is provided for illustration only, these methods, steps and/or actions may be performed in a different order and not be limited to the specific order shown in accompanying drawing(s) and described in specification without departing from the scope of the claims.

The foregoing description of the present application enables those ordinary skilled in the art to perform or utilize the present application. For those ordinary skilled in the art, various modifications of the disclosure are obvious; the general principle defined in the present application may be applied to other alternations without departing from the spirit and scope of the present application. Accordingly, the present application is not limited to the embodiments and designs described in the disclosure, but consistent with the widest scope of the principle and novelty disclosed in the present application.

Claims

1. A method, in a MeNB, for performing a DRX configuration for a dual connectivity system, the method comprising:

transmitting, to a SeNB, a DRX cycle length of a macro cell associated with the dual connectivity system ;

obtaining, from the SeNB, DRX configuration information of a small cell associated with the dual connectivity system;

transmitting, to a user equipment, a DRX configuration of the macro cell and a DRX configuration of a small cell;

transmitting, to the SeNB, a measurement report associated with a frequency measurement of a small cell according to a measurement report from the user equipment.

2. The method according to claim 1 , wherein the step of transmitting a DRX cycle length of a macro cell associated with the dual connectivity system to a SeNB further comprising:

transmitting, to the SeNB, DRX cycle length information of the macro cell determined according to measurement requirement and characteristics of traffic data of the user equipment;

if a DRX cycle length from a SeNB is accepted, transmitting, to the

SeNB, a DRX cycle length of a macro cell configured according to a DRX cycle length of a small cell.

3. A method, in a SeNB, for performing a DRX configuration for a dual connectivity system, the method comprising:

obtaining DRX cycle length information of a macro cell from a MeNB ; transmitting, to a MeNB, a DRX configuration of a small cell that is determined according to the DRX cycle length information from the MeNB ; receiving a measurement report associated with frequency of a small cell from the MeNB;

determining a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report from the MeNB .

4. The method according to claim 3, wherein the step of transmitting, to a MeNB, a DRX configuration of a small cell that is determined according to the DRX cycle length information from the MeNB further comprising:

transmitting, to a MeNB, a DRX configuration of a small cell determined according to DRX cycle length information of a macro cell and characteristics of traffic data of a user equipment if a DRX cycle length of a macro cell is accepted;

transmitting, to a MeNB, a DRX configuration of a small cell determined according to characteristics of traffic data for user equipment if a DRX cycle length of a macro cell is not accepted;

transmitting, to a MeNB, a DRX configuration of a small cell determined according to a DRX cycle length of the MeNB if the DRX cycle length of a small cell is not accepted by the MeNB.

5. A method, in a MeNB, for performing a DRX configuration for a dual connectivity system, the method comprising:

transmitting, to a user equipment, a DRX cycle length for determining a measurement requirement;

obtaining, from a SeNB, DRX configuration information of a small cell associated with the dual connectivity system;

transmitting, to the user equipment, DRX configuration information of a macro cell and DRX configuration of a small cell associated with the dual connectivity system;

transmitting a measurement report associated with frequency measurement of a small cell to the SeNB according to the measurement report from the user equipment.

6. A method, in a SeNB, for performing a DRX configuration for a dual connectivity system, the method comprising:

transmitting DRX configuration information of a small cell to a MeNB; receiving a measurement report associated with frequency of a small cell from a MeNB; determining a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report from the MeNB .

7. A method, in a MeNB, for performing a DRX configuration for a dual connectivity system, the method comprising:

obtaining, from a SeNB, DRX configuration information of a small cell associated with a dual connectivity system;

transmitting, to a user equipment, a DRX configuration of a small cell and a DRX configuration of a macro cell associated with the dual connectivity system;

transmitting a measurement report associated with frequency measurement of a small cell to the SeNB according to a measurement report from the user equipment.

8. A method, in a SeNB, for performing a DRX configuration for a dual connectivity system, the method comprising:

determining that DRX configuration information of a macro cell is not received from a MeNB for a period of time;

transmitting, to a MeNB, DRX configuration information of a small cell determined according to characteristics of traffic data of a SeNB;

receiving a measurement report associated with frequency of a small cell from a MeNB;

9. A method, in a user equipment, for performing a DRX configuration for a dual connectivity system, the method comprising:

obtaining DRX configuration information associated with a dual connectivity system from a MeNB;

transmitting a measurement report, measured according to frequency measurement requirement corresponding to the determined DRX cycle length, to the MeNB.

10. A method, in a user equipment, for performing a DRX configuration for a dual connectivity system, the method comprising:

obtaining, from a MeNB, DRX configuration information associated with a dual connectivity system;

obtaining, from the MeNB, DRX cycle length information for determining a measurement requirement;

transmitting, to the MeNB, a measurement report measured according to frequency measurement requirement corresponding to the determined DRX cycle length.

11. An apparatus, in a MeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a transmitting unit configured to transmit, to a SeNB, DRX cycle length information of a macro cell associated with a dual connectivity system, to transmit, to the user equipment, a DRX configuration of the macro cell and a DRX configuration of a small cell associated with the dual connectivity system, and to transmit a measurement report associated with frequency measurement of a small to the SeNB based on the measurement report from the equipment;

a receiving unit configured to obtain, from the SeNB, a DRX configuration information of the small cell associated with a dual connectivity system.

12. An apparatus, in a SeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a transmitting unit configured to transmit a DRX configuration of a small cell, determined according to DRX cycle length information from a MeNB, to the MeNB;

a receiving unit configured to obtain a measurement report associated with frequency of a small cell from the MeNB and to obtain DRX cycle length information of a macro cell from the MeNB ;

a determining unit configured to determine a serving small cell suitable to a user equipment or coordinate interference between small cells according to the measurement report from the MeNB .

13. An apparatus, in a MeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a transmitting unit configured to transmit, to a user equipment, a DRX cycle length for determining a measurement requirement, to transmit, to the user equipment, DRX configuration information of a macro cell and DRX configuration information of a small cell associated with the dual connectivity system, and to transmit a measurement report associated with frequency measurement of a small cell to the SeNB based on a measurement report from the user equipment;

a receiving unit configured to obtain, from the SeNB, DRX configuration information of the small cell associated with the dual connectivity system.

14. An apparatus, in a SeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a transmitting unit configured to transmit, to a MeNB, DRX configuration information of a small cell determined according to characteristics of traffic data of a SeNB;

a receiving unit configured to receive a measurement report associated with frequency of a small cell from a MeNB ;

a determining unit configured to determine a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report from the MeNB, and to determine that DRX configuration information of a macro cell is not received from a MeNB for a period of time.

15. An apparatus, in a MeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a receiving unit configured to obtain, from a SeNB, DRX configuration information of a small cell associated with a dual connectivity system;

a transmitting unit configured to transmit, to the user equipment, a

DRX configuration of a small cell and a DRX configuration of the macro cell associated with a dual connectivity system, and to transmit a measurement report associated with frequency measurement of a small cell to the SeNB according to a measurement report from the user equipment.

16. An apparatus, in a SeNB, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a transmitting unit configured to transmit DRX configuration information of a small cell to a MeNB;

a determining unit configured to determine a serving small cell suitable to a user equipment or coordinating interference between small cells according to the measurement report for the MeNB, and to determine that DRX configuration information of a macro cell is not received from a MeNB for a period of time.

17. An apparatus, in a user equipment, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a transmitting unit configured to transmit, to the MeNB, a measurement report measured according to frequency measurement requirement corresponding to the determined DRX cycle length;

a receiving unit configured to obtain the DRX configuration information associated with a dual connectivity system from a MeNB.

18. An apparatus, in a user equipment, for performing a DRX configuration for a dual connectivity system, the apparatus comprising:

a receiving unit configured to obtain, from a MeNB, DRX cycle length information for determining measurement requirement, and to obtain DRX configuration information associated with a dual connectivity system from a MeNB.