WO2015105378A1

WO2015105378A1 - Method and device for fast receiving and transmitting ul data and dl data

Info

Publication number: WO2015105378A1
Application number: PCT/KR2015/000240
Authority: WO
Inventors: Yingyang Li; Chengjun Sun
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2014-01-09
Filing date: 2015-01-09
Publication date: 2015-07-16
Also published as: CN104780559A

Abstract

A method for fast receiving and transmitting Downlink (DL) and Uplink (UL) data includes: processing, by a User Equipment (UE), DL synchronization according to a Discovery Signal (DiS), or according to the DiS and a Cell-specific Reference Signal (CRS) after a cell X is opened; measuring, by the UE, Reference Signal Receiving Power (RSRP)/Reference Signal Receiving Quality (RSRQ) and/or Channel State Information (CSI) information of the cell X based on the DiS and reporting the RSRP/RSRQ and/or CSI information to a serving cell, which is currently working; receiving, by the UE, a Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) on the cell X, detecting trigger information of a random access process on the cell X, executing the random access process, measuring and reporting, by the UE, the CSI information to the cell X. With the method and terminal device in the present disclosure, a UL synchronization process of the UE and a process for the UE to measure and feed back the CSI may be speeded up, the transition from the opening of the cell to a moment that the UL and DL data of the UE may be actually received and transmitted may be reduced, the ON/OFF operation of the cell may be effectively supported and the performance of the system may be enhanced.

Description

METHOD AND DEVICE FOR FAST RECEIVING AND TRANSMITTING UL DATA AND DL DATA

The present disclosure relates to a wireless communication system, and more particularly, to a method and device for fast opening a serving cell, receiving and transmitting Downlink (DL) data and Uplink (UL) data.

In the Long Term Evolution (LTE) system of a 3rd Generation Partnership Project (3GPP) system, length of each radio frame is 10ms, which is equally divided into 10 sub-frames. Each DL Transmission Time Interval (TTI) is defined on one sub-frame. Figure 1 illustrates structure of a sub-frame. Each DL sub-frame includes two timeslots. As for length of a normal Cyclic Prefix (CP), each timeslot includes seven Orthogonal Frequency Division Multiplexing (OFDM) symbols. As for length of an extended CP, each timeslot includes six OFDM symbols. Resource allocation granularity in each sub-frame is a Physical Resource Block (PRB). One PRB includes 12 consecutive sub-carriers in frequency and corresponds to one timeslot in time. Two PRBs in two timeslots on a same sub-carrier of a sub-frame are called a PRB pair. In each PRB pair, each Resource Element (RE) is the minimum unit of a time-frequency resource. That is, each RE is a sub-carrier in frequency and is an OFDM symbol in time. The REs may be used for implementing different functions. For instance, partial REs may be used for transmitting a Cell-specific Reference Signal (CRS), a specific Demodulation Reference Signal (DMRS) of the user and a Channel State Indication-Reference Signal (CSI-RS), etc.

The first n OFDM symbols of each DL sub-frame may be used for transmitting DL control information. The control information includes: a Physical Downlink Control Channel (PDCCH) and other control information, n may equal to 0, 1, 2, 3 or 4. The rest of the OFDM symbols may be used for transmitting a Physical Downlink Shared Channel (PDSCH) or an Enhanced Physical Downlink Control Channel (EPDCCH). In the LTE system, The PDCCH bears Downlink Control Information (DCI), which allocates UL channel resources or DL channel resources. DCI for allocating the DL channel resources is called a DL grant signaling and DCI for allocating the UL channel resources is called a UL grant signaling. The authentication signaling of different UEs is independently transmitted. The DL grant signaling and UL grant signaling are independently transmitted.

In the LTE system, DL data is transmitted based on a Hybrid Automatic Repeat Request (HARQ) scheme. In order to support channel adaption to optimize a DL transmission performance, the UE needs to feed back the CSI of the UL. The CSI may further include: a Rank Indication (RI) of a channel, a Precoding Matrix Indicator (PMI) and a Channel Quality Indicator (CQI), etc. Multiple kinds of DL transmission modes are defined in the LTE system. For instance, as for the DL, a closed-loop Multiple Input Multiple Output (MIMO) transmission mode, an open-loop MIMO transmission mode and a transmit diversity transmission mode, etc., maybe included. As for different transmission modes, formats of CSI feedback are different.

In order to further enhance a peak transmission rate, the LTE system supports Carrier Aggregation (CA). The network may configure multiple carriers for one UE. One carrier is a Primary cell (Pcell) and the other are Secondary cells (Scell). An initial state of a configured Scell is inactive. The network may activate or deactivate one Scell with indication information in a Media Access Control (MAC) Control Element (CE). It may be assumed that the UE activates a configured Scell in a sub-frame n via the MAC CE. The UE performs ordinary UL and DL transmission in the Scell from a sub-frame (n+8). The UL and DL transmission includes: transmission of a Sounding Reference Signal (SRS), feedback of the CSI, detection PDCCH in the Scell and detection the PDCCH of the Scell in the Pcell, etc. Simply speaking, after the UE receives the MAC CE for activating the Scell, the UE cannot work in the Scell for at least 8ms.

As for Aperiodic CSI (A-CSI) reporting, the fastest mode may be that the UE receives a UL Grant for activating the A-CSI in a sub-frame (n+8) and then feeds back the A-CSI information in a sub-frame (n+8+k), k is larger than or equals to 4. After certain processing time delay, an eNB may perform DL data transmission with information of the A-CSI reporting. As for the UL transmission, if the Scell UL is in an out-of-step state, the UE may detect a PDCCH order for activating a random access process of the Scell as early as the sub-frame (n+8). Then, the UE only can send a preamble in a sub-frame (n+8+k2), k2 is larger than or equals to 6. Then, the UE only can obtain UL synchronization after receiving a Random Access Response (RAR) to perform UL transmission.

In an evolution version of the LTE system, an important technical point is enhancing a small cell. Specifically speaking, three scenarios are included. The first scenario is that a macro-cell and a small cell are deployed at a same frequency. The macro-cell provides coverage and hotspot enhancement of the small cells may be implemented via dense deployment. Here, the small cells may be divided into one or multiple cell-clusters. The second scenario may be that the marco-cell and the small cells are deployed at different frequencies. Similarly, the macro-cell provides the coverage and the hotspot enhancement of the small cells may be implemented via the dense deployment. Here, the small cells may be divided into one or multiple cell-clusters. Here, one cluster of small cells may be deployed in a same building. The third scenario may be that only the small cells are deployed. The small cells may be divided into one or multiple cell-clusters. In each cluster, the small cells are densely deployed. One cluster of small cells may be deployed in a same building. In the three scenarios, a common problem is that the deployment of the small cells is too dense and the small cells seriously interfere with each other. In the first scenario, there may be interference from the macro-cell. Therefore, how to process the interference problem in the above scenarios of the small cells is a problem to be solved.

According to the current Radio Access Network work group 1 (RAN1) discussion，a kind of promising technique is that one small cell is opened when needed and a small cell, which is not needed, may be closed, so that an interference level of the whole network may be reduced and throughput of the system may be enhanced. This kind of technique may be called a small cell ON/OFF hereinafter. Because, in the current LTE system, even the small cell does not serve any UE, the small cell still needs to transmit a Cell-specific Reference Signal (CRS) and the CRS is transmitted with relatively high power, resulting in interfering with other small cells serving the UEs. More immediately, the interference to the small cells serving the UEs may be reduced and the system performance may be enhanced by turning off the small cell, which does not serve the UE at the moment, since it does not transmit the CRS. Energy loss of the eNB is reduced by turning off the small cell, which is not needed. However, time is needed to turn on or turn off the small cell. If the processing time delay is too long, the small cell ON/OFF technique does not have any advantage and even makes the system performance reduce.

In order to effectively support the small cell ON/OFF operation and reduce the time used for turn on or turn off the small cell, in the current RAN1 discussion, a Discovery Signal (DiS) is introduced. As shown in figure 2, on the premise of power saving, as for a small cell in an OFF state, a channel state, such as Reference Signal Receiving Power (RSRP) and Reference Signal Receiving Quality (RSRQ) of the small cell still can be measured, so that the network may select the optimal small cell according to service distribution and channel state and utilize the small cell to serve the UL&DL data transmission of the UE as quickly as possible. Furthermore, after the state of the small is switched to ON, the DiS may still be sent out. In order to avoid long time delay resulting from the switching of the cell, in the current RAN1 discussion, the CA technology or Dual Connectivity technology may be used. That is, the UE may maintain the connection established in one cell (Generally, the cell may the macro-cell) to avoid the handover process. At the same time, with the CA or Dual Connectivity technology, another cell may be used to support enhanced UL and DL transmission. Since the handover is not needed, transition time needed by the UE is short. As shown in figure 3, taking the CA for example, when the small cell is in the OFF state, the UE may perform Radio Resource Management (RRM)-related measurement based on the DiS and report to another cell (such as the macro-cell) connected with the UE. According to actual service and channel state, the macro-cell may switch the state of the small cell to the ON state and send a Scell activation indication to the UE (recorded as the sub-frame n). Therefore, the state of the small cell is switched to the ON and the UE may detect the PDCCH of the small cell and report the CSI in sub-frame (n+8).

How to reasonably use the DiS technology and one of the CA technology and Dual Connectivity technology to reduce the impact of the transition time on closing and opening the small cell and optimize the performance of the small cell ON/OFF is a problem to be solved by the present disclosure.

Embodiments of the present disclosure disclose a method and device for fast opening a serving cell, receiving and transmitting UL data and DL data.

In order to implement the above objective, the present disclosure may adopt following technical schemes.

A method for fast receiving and transmitting Downlink (DL) and Uplink (UL) data includes:

processing, by a User Equipment (UE), DL synchronization according to a Discovery Signal (DiS) or according to the DiS and a Cell-specific Reference Signal (CRS) after a cell X is opened;

measuring, by the UE, Reference Signal Receiving Power (RSRP)/Reference Signal Receiving Quality (RSRQ) and/or Channel State Information (CSI) information of the cell X based on the DiS and reporting the RSRP/RSRQ and/or CSI information to a serving cell, which is currently working;

receiving, by the UE, a Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) on the cell X, detecting trigger information of a random access process on the cell X, executing the random access process, measuring and reporting, by the UE, the CSI information to the cell X.

Preferably, the method further includes:

obtaining transmission timing of a Physical Random Access Channel (PRACH) Preamble in the random access process based on reception timing of the DiS of the cell X.

Preferably, the method for receiving, by the UE, the PDCCH on the cell X and detecting the trigger information of the random access process on the cell X includes: receiving, by the UE, the PDCCH on the cell X before a sub-frame (n+t0) and detecting the trigger information of the random access process on the cell X on the PDCCH; n is a number of a sub-frame, in which the UE detects indication information for activating the cell X and t0 is a constant.

Preferably, t0 equals to 8.

Preferably, the method for detecting the trigger information of the random access process on the cell X on the PDCCH includes: starting detecting, by the UE, a PDCCH order from a sub-frame (n+k3), 0≤k3< t0.

The method for detecting the trigger information of the random access process on the cell X on the PDCCH includes: detecting, by the UE, trigger information PDCCH order of the random access process on the cell X before the UE receives the indication information for activating the cell X.

Preferably, the method further includes:

transmitting, by the UE, a PRACH Preamble in the random access process before the UE receives the indication information for activating the cell X; or

transmitting, by the UE, the PRACH Preamble after the UE receives the indication information for activating the cell X; or

transmitting, by the UE, the PRACH Preamble on the cell X after T ms time delay from a sub-frame, in which the indication information for activating the cell X is received, 0≤T<t0.

Preferably, the method for detecting the trigger information of the random access process on the cell X includes: extracting, by the UE, the trigger information of the random access process from the received indication information for activating the cell X.

Preferably, the method further includes:

configuring PRACH resources used by the UE in the random access process in first N UL sub-frames after the cell X is opened or several sub-frames before the indication information for activating the cell X, N<t0 and t0 is a constant.

Preferably, a sub-frame used for the PRACH is configured in an implicit mode or explicit mode.

Preferably, the explicit mode includes: configuring that which sub-frames comprise a configured PRACH channel when the cell X is just opened or indicating that which sub-frames comprise the configured PRACH channel in the trigger when the cell X is configured as a Scell or a Dual Connectivity (DC) serving cell.

Preferably, the method for measuring, by the UE, the RSRP/RSRQ and CSI information based on the DiS includes:

measuring, by the UE, the RSRP/RSRQ of the cell X and the CSI information of the cell X based on the DiS, reporting the RSRP/RSRQ and CSI information to a servicing cell, which has been activated, of the UE; or

reporting, by the UE, a measurement value to the serving cell, which has been activated, to indicate a RSRQ characteristic and CSI characteristic.

Preferably, the method further includes:

sending, by a network, the measured CSI information to the cell X when the UE detects the CSI information of the cell based on the DiS, so that the cell X schedules the PDSCH before a sub-frame (n+t0), t0 is a constant.

Preferably, the method for measuring the RSRQ of the cell X based on the DiS includes: measuring the RSRP based on the DiS, measuring a Received Signal Strength Indication (RSSI) on a time-frequency resource configured with a high-layer signaling for measuring the RSSI and determining the RSRQ according to the measured RSRP and RSSI;

the time-frequency resource for measuring the RSSI includes: one or multiple periodically-configured Orthogonal Frequency Division Multiplexing (OFDM) symbols, one or more periodically-configured sub-frames, time-frequency resources periodically configured taking a Resource Element (RE) as a granularity; wherein REs in each period are allocated to one or multiple OFDM symbols or one or multiple sub-frames.

Preferably, the method for measuring the CSI information of the cell X based on the DiS includes: configuring a time-frequency resource of the UE for measuring interference with a high-layer signaling and measuring the CSI information on the configured time-frequency resource;

the time-frequency resource for measuring the interference includes: a time-frequency resource for measuring the interference configured with a configuration method of Zero Power (ZP) ZP CSI-RS; a ZP CSI-RS resource obtained via extension with a CRS-RS multiplexing method in one sub-frame, a periodically-configured self-defined RE pattern, all REs of one periodically-configured OFDM symbol, all REs of multiple OFDM symbols, all REs of a sub-frame or all REs of multiple sub-frames; wherein the high-layer signaling indicates ZP CSI-RS resources of the UE for measuring the interference in the ZP CSI-RS resources obtained by the extension.

Preferably, when the CSI information is Aperiodic CSI (A-CSI) information, the method for measuring and reporting, by the UE, the CSI information to the cell X includes: receiving, by the UE, the PDCCH on the cell X before a sub-frame (n+t0), detecting trigger information of the A-CSI on the cell X on the PDCCH, measuring the CSI and transmitting an A-CSI report, n is a number of a sub-frame, in which the UE detects indication information for activating the cell X, t0 is a constant.

Preferably, the method for detecting the trigger information of the A-CSI on the cell X on the PDCCH includes: starting detecting, by the UE, the trigger information of the A-CSI from a sub-frame (n+k1), 0≤k1<t0.

Preferably, the method for detecting the trigger information of the A-CSI on the cell X on the PDCCH includes: detecting, by the UE, the trigger information of the A-CSI on the cell X before the indication information for activating the cell X is received.

Preferably, the method for transmitting the A-CSI report includes:

transmitting the A-CSI report on the cell X after the UE receives the indication information for activating the cell X; or

transmitting the A-CSI report on the cell X after T ms time delay from a sub-frame, in which the indication information for activating the cell X is received, 0≤T<t0.

Preferably, the method further includes:

triggering the UE to transmit the A-CSI report on the cell X with the indication information for activating the cell X.

Preferably, the method further includes:

allocating extra Non-Zero Power (NZP) Channel State Indication-Reference Signal (CSI-RS) and Channel State Indication-Interference Measurement (CSI-IM) resources except for periodically-allocated NZP CSI-RS and CSI-IM resources in first M sub-frames after the cell X is opened when the CSI information of the UE is measured based on a measurement mode of the CSI-RS, M<t0 and t0 is a constant.

Preferably, the method further includes: respectively configuring the extra NZP CSI-RS and CSI-IM resources for two CSI sub-frame sets when the UE is configured with the two CSI sub-frame sets and respectively reports the CSI information of a corresponding sub-frame set.

Preferably, as for a Time Division Duplexing (TDD) system, the cell works in an Enhanced Interference Mitigation and Traffic Adaptation (eIMTA) mode or works according to DL sub-frames in first N₁ UL sub-frames after the cell X is just opened, N₁<t0.

Preferably, the extra NZP CSI-RS and CSI-IM resources are configured in an implicit mode and RE resource configuration used for configuring NZP CSI-RS and CSI-IM resources with a high-layer signaling is multiplexed; or the extra NZP CSI-RS and CSI-IM resources are configured in an explicit mode.

Preferably, the explicit mode includes: configuring that which sub-frames comprise the extra NZP CSI-RS and CSI-IM resources with a high-layer signaling when the cell X is just opened or adding indication information of the extra NZP CSI-RS and CSI-IM resources to a DL Grant transmitted to the UE; or indicating configuration information of extra NZP CSI-RS and CSI-IM resources when the cell X is activated.

Preferably, REs, which cannot be used for transmitting the PDSCH, are indicated in a sub-frame, at which the extra NZP CSI-RS and CSI-IM resources are located.

A terminal device for fast receiving and transmitting Downlink (DL) data and Uplink (UL) data, includes: a Discovery Signal (DiS) reception and DL synchronization unit, a first channel state measurement and reporting unit, a DL information reception unit, a random access unit and a second channel state measurement and reporting unit.

The DiS reception and DL synchronization unit is to receive a DiS, process DL synchronization according to the DiS or according to the DiS and a Cell-specific Reference Signal (CRS) after a cell X is opened;

the first channel state measurement and reporting unit is to measure Reference Signal Receiving Power (RSRP)/Reference Signal Receiving Quality (RSRQ) and/or Channel State Information (CSI) information of the cell X based on the DiS and report the RSRP/RSRQ and/or CSI information to a serving cell, which is currently working;

the DL information reception unit is to receive a Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) on the cell X;

the random access unit is to detect trigger information of a random access process on the cell X and execute the random access process; and

the second channel state measurement and reporting unit is to measure and report the CSI information to the cell X.

With the method and device of the present disclosure, the UL synchronization process of the UE may be speeded up, a process for the UE to measure and fed back the CSI may be speeded up. The transition time from a moment that the cell is opened to a moment that the UE may receive and transmit the UL and DL data of the UE may be reduced. Therefore, the ON/OFF operation of the cell may be effectively supported and the performance of the system may be enhanced.

Figure 1 illustrates structure of a sub-frame;

Figure 2 illustrates DiS transmission;

Figure 3 is a flow chart illustrating a process for opening a cell based on the DiS;

Figure 4 is a flow chart of the present disclosure;

Figure 5 is a flow chart illustrating a process for measuring and reporting CSI based on DiS in accordance with various embodiments of the present disclosure; and

Figure 6 is a diagram illustrating basic structure of a terminal device in accordance with various embodiments of the present disclosure.

To make the objective and technical solution of the examples of the present disclosure more apparent, the present disclosure may be described in detail with reference to accompanying figures.

For the clarity of description, a small cell, for which a cell ON/OFF operation is performed, is denoted as a cell X. In order to effectively support the ON/OFF operation of the cell X, transition time from a moment that the cell X is opened to a moment that the cell X may really receive and send UL data from/to the UE may need to be reduced. Based on this, the present disclosure provides that an eNB may configure a UE to measure a DiS of the cell X to speed up a UL synchronization process of the UE and speed up the UE measurement and CSI feedback process, so that the UE may start receiving or transmitting the DL&UL data at a faster speed after the cell X is opened.

Figure 4 is a basic flow chart of a method in accordance with various embodiments of the present disclosure.

In block 401, a UE may obtain DL synchronization of a cell X according to a DiS of the cell X. In another example, after the cell X is opened, the UE may enhance DL synchronization accuracy according to a CRS after the cell X is opened.

Basically, the UE may obtain the DL synchronization of the cell X according to the DiS of the cell X, so that the UE may implement DL synchronization as quickly as possible and the transmission of the DL control information may be speeded up. Furthermore, after the cell X is opened, the DL synchronization accuracy may be enhanced according to the CRS after the cell X is opened.

In block 402, the UE may measure the RSRP/RSRQ and/or CSI information of the cell X according to the DiS of the cell X and report the RSRP/RSRQ and CSI information to a serving cell, which may be currently working.

The UE may measure the RSRP/RSRQ and/or CSI information according to the DiS before the cell X is activated and report the RSRP/RSRQ and/or CSI information, so that the network may determine whether to open the cell X according to the information reported by each UE, such as the RSRP/RSRQ and/or CSI information. Preferably, if the CSI information is measured and reported before the cell X is activated, on the one hand, the reported CSI information may be used as a reference for determining whether to open the cell X by the network. On the other hand, compared with the current measurement of the CSI information based on the CRS, state information of a DL channel may be obtained as early as possible. Therefore, the DL data may be transmitted in a shorter period of time after the cell X is opened.

In block 403, the UE may receive a PDCCH and PDSCH of the cell X and detect trigger information of a random access process of the cell X, execute the random access process, measure and report the accurate CSI information.

In this block, the random access process and a mode for reporting the CSI information may be implemented with an existing mode. However, since in block 401, the DiS of the cell X speeds up the speed for the UE to obtain the DL synchronization, preferably, the UE may receive the PDCCH and PDSCH of the cell X as early as possible, trigger the random access process as early as possible, so that the UL synchronization between the UE and the cell X may be implemented as quickly as possible and the measurement and report of the CSI information may be ahead of schedule.

Till then, the flow in figure 4 ends. It can be seen from the flow of figure 4 that in the present disclosure, the ON/OFF operation of the cell X may be effectively supported via following three processing modes. The first one is that the DL synchronization may be performed in advance according to the DiS and the UL synchronization process of the UE may be speeded up. The second one is that the CSI information of the cell X may be measured according to the DiS before the cell X is activated. The third one is that the DL synchronization may be performed in advanced according to the DiS to speed up the process for measuring the UE and feeding back the accurate CSI information. The specific implementation of the above three processing modes may be described hereinafter via three preferred embodiments.

Embodiment one

This embodiment may introduce the preferred implementation mode for speeding up the UL synchronization process.

In order to transmit a UL control signal and UL data in the cell X, first of all, the UE may need to finish UL synchronization between the UE and the cell X. In the existing CA scheme, it may be assumed that the Scell and Pcell may belong to different Time Advance Groups (TAG)s. The UL synchronization may be obtained by triggering the random access process of the UE on the Scell. It may be assumed that if the UE receives indication information for activating the Scell in a sub-frame n, the UE may just start detecting a PDCCH order triggering the random access process of the Scell from a sub-frame (n+t0). Then, the UE only may send a preamble at least in a sub-frame (n+t0+k2), k2 may be larger than or equal to 6. A Physical Random Access Channel (PRACH) resource may be allocated to the sub-frame (n+t0+k2). Then, the UE may obtain the UL synchronization after the UE receives a Random Access Response (RAR), t0 may be a constant. For instance, in the LTE CA system, t0 may equal to 8. It may be assumed that time delay of the RAR is 3ms. In the above scheme, the UE cannot perform the UL transmission, such as cannot feed back DL channel CSI information, in at least 17ms from a moment that the eNB transmits the indication information for activating the Scell. Therefore, the performance of the UL and DL transmission based on the ON/OFF scheme of the cell may be affected.

In practice, since the DiS of the cell X is periodically transmitted in a period of fixed length, the UE may determine reception timing of the DL signal of the cell X, i.e. finish the DL synchronization based on the DiS. Based on the reception timing, the UE may obtain transmission timing of a PRACH preamble. For instance, the reception timing of the DiS may be taken as the transmission timing the PRACH preamble. Depending on the design of the DiS, the accuracy of the DL reception timing obtained by the UE according to the DiS may be different. Generally, the PRACH preamble may be transmitted according to the DL timing. Since the cell X may transmit a command of Timing Advance (TA) to adjust the UL transmission of the UE after the cell X receives the PRACH preamble, so that the UE may obtain accurate UL transmission timing. A method for processing the random access process of the cell X in the present disclosure may be described hereinafter. According to different design, there may be different methods for changing the random access process, which may be respectively described hereinafter.

First of all, the method for speeding up the trigger of the random access process in the present disclosure may be described.

In the first method, it may be assumed that the UE just may start detecting the trigger information PDCCH order of the random access process after the UE receives the indication information for activating the cell X. It may be defined that the UE may detect the indication information for activating the cell X in the sub-frame n. According to the assumption of the current CA, if the UE may transmit information, such as the SRS and CSI report at a moment (n+t0), the UE may also transmit the PRACH preamble. Therefore, in the present disclosure, since the UE has obtained the DL synchronization of the cell X according to the DiS via the processing of the block 401, the UE may start detecting the PDCCH order in a sub-frame (n+k3) and may not need to wait until the sub-frame (n+t0), k3 may be less than t0 and larger than or equal to 0. Here, k3 may be determined according to some factors, which actually limit the activation of the Scell by the UE and k3 may provide some transition time for the cell X to receive the PRACH preamble. Therefore, the number of a sub-frame, in which the UE may transmit the PRACH preamble, may be (n+k3+k2). The sub-frame (n+k3+k2) may include configured PRACH channel resources. Based on the timing relationship between the conventional PDCCH order and PRACH preamble, k2 may be larger than or equal to 6. Especially, k3 may equal to 2 and the number of the starting sub-frame, in which the UE may transmit the PRACH preamble, may be (n+k3+k2=n+8), by which in the conventional CA system, the limitation of the UL transmission on the Scell, which is just activated, performed by the UE may be satisfied. In another example, since the UE cannot perform other UL transmission of the cell X when the cell is just opened and before the UL synchronization is obtained. Therefore, it may be considered that the UE may be configured to make a response to the PDCCH order at a faster speed. That is, the minimum value of k2 may be less than 6.

In a second method, it may be assumed that before the UE receives the indication information for activating the cell X, the PDCCH order for triggering the random access process of the cell X may be detected. With this method, the PDCCH order may need to be transmitted in another serving cell (such as the Pcell), which may have been activated, of the UE. That is, the transmission of the PRACH preamble in the cell X may be triggered by a cross-carrier scheduling method. This method may apply to a situation that the cross-carrier scheduling of the UL and DL transmission of the cell X is configured. If it is configured that the cell X is self-scheduled, the PDCCH order of the cell X may be specially processed. Specially speaking, all PDCCH orders of the cell X may be transmitted in another activated serving cell (such as Pcell) of the UE. In another example, the PDCCH orders may be transmitted in another activated serving cell when the cell X is being activated, while the UE may still detect the PDCCH order in the cell X in other moments.

It may be assumed that a sub-frame of the PDCCH order may be a sub-frame m. The UE may transmit the PRACH preamble in a sub-frame (m+k4). Here, a PRACH channel may be configured for the sub-frame (m+k4). If the timing relationship from the PDCCH order to the transmission of the PRACH preamble by UE in the conventional LTE CA is still used, k4 may be larger than or equal to 6.

Here, the order of a sub-frame, in which the UE may transmit the PRACH preamble, and a sub-frame, in which the UE may receive the indication information for activating the cell X may not be limited. Therefore, when the sub-frame (m+k4), in which the UE may transmit the PRACH preamble is earlier than the sub-frame n, in which the UE may receive the indication information for activating cell X, the network may need to configure the cell in a state before the network needs to send the indication information for activating the cell X. The state is that although the cell X does not transmit any signal in DL, the cell X already may have started detecting the preamble. The RAR may be transmitted after the cell X is activated.

In another example, another timing relationship may be that it may be limited that after the UE receives the indication information for activating the cell X, the UE may transmit the PRACH preamble in the cell X. It may be defined that if the UE detects the PDCCH order in the sub-frame m, the sub-frame (m+k4), in which the UE may transmit the PRACH Preamble, may be in front of the sub-frame n, in which the UE may receive the indication information for activating the cell X. Furthermore, it may be limited that the sub-frame (m+k4), in which the UE may transmit the PRACH preamble, may be T time delay after the sub-frame n, in which the UE may receive the indication information for activating the cell X. T may be larger than 0ms and less than or equal to t0 ms. The time delay T may provide some preparation time for the cell X to receive the PRACH preamble of the UE.

The third method may be that the random access process of the UE may be triggered when the cell X is activated. Here, a parameter of the PRACH preamble of the UE may be configured with the high-layer signaling. The random access process may be initiated according to the parameter of the configured PRACH preamble after the UE receives the indication information of the activated cell X. In this method, the trigger information of the random access process may not adopt the PDCCH order, but may be directly carried in the indication information for activating the cell X. Specifically, the activation signaling may implicitly indicate that the UE may need to initiate the random access process of the cell X while the activation signaling indicates the activation of the cell X. In another example, new indication information, such as one bit, may be added to the activation signaling to explicitly indicate whether to trigger the random access process of the UE in the cell X. In another example, signaling structure of the cell X may be modified and a necessary configuration parameter of the PRACH preamble may be added, so that after the UE receives new signaling for activating the cell X, the random access process may be initiated. It may be defined that the UE detects the indication information for activating the cell X in the sub-frame n, the sub-frame, in which the UE may transmit the PRACH preamble, is the sub-frame (n+k2). The sub-frame (n+k2) may include configured PRACH channel resources. Based on the conventional timing relationship between the PDCCH order and the PRACH preamble, k2 may be larger than or equal to 6. In order to satisfy the limitation put forwarded by the conventional LTE system on the UL transmission of the Scell, which is just activated, k2 may be defined as larger than or equal to t0.

In the above description of the random access process, the timing relationship from the reception of the trigger information (such as the PDCCH order or activation signaling of the cell X) of the random access process of the UE to the transmission of the PRACH preamble may be defined and it may be demanded that the PRACH preamble may be transmitted in a sub-frame configured with the PRACH channel resources. The sub-frame configured with the PRACH channel resources may be configured for the UE via the high-layer signaling. For instance, when the cell X is configured as the Scell or a Dual Connectivity (DC) serving cell, the configuration information of the PRACH channel resources may be configured with the configuration signaling when the cell X is opened. According to the scheme of the conventional LTE CA system, the configured PRACH resources may be allocated according to a certain period. Therefore, under a premise that the UE may satisfy the timing relationship between the PDCCH order or the activation signaling of the cell X and the transmission of the PRACH preamble, the preamble only may be transmitted with the periodically-allocated PRACH channel resources.

A method for increasing the allocated PRACH channel resources may be described hereinafter. In practice, since when the cell X is just opened, UL data cannot be transmitted in the first several UL sub-frames. For instance, generally, in the UL data transmission, the UL Grant first may need to be detected first. Then, the UL data may be transmitted after the time delay of 4ms. Therefore, at least the first four UL sub-frames are idle after the cell X is opened. In another example, according to the limitation of the conventional LTE CA system, if the UE may transmit the UL signal in sub-frame (n+t0), the first t0 UL sub-frames may be idle after the cell X is opened. The present disclosure may put forward that based on the periodically-allocated PRACH resources configured for the UE, extra PRACH resources may be configured, so that the UE may transmit the PRACH preamble at a faster speed. Here, the extra PRACH resources may be configured in the first several sub-frames after the UE receives the indication information for activating the cell X. For instance, the extra PRACH resources may be allocated in the above idle sub-frames after the cell X is opened. In another example, the extra PRACH resources may be configured in more sub-frames in the above idle sub-frames after the cell X is opened. In another example, it may be assumed that when the UE receives the indication information for activating the cell X and the cell X may have been opened and been serving the UL transmission of other UEs, the extra PRACH resources may still be allocated to adjacent sub-frames of the sub-frame, in which the UE may receive the indication information for activating the cell X. Here, other timing requirements may be put forwarded. For instance, the PRACH channel only may be allocated in a sub-frame after a period of time delay T from a moment that the indication information for activating the cell X is received. T may be larger than 0 and less than or equal to t0. In another example, if the cell X has already activated the UL reception operation before the cell X starts transmitting the DL signal, the UL resources of the UL sub-frame may be used for allocating the PRACH channel resources before the cell X start transmitting the DL signal. Accordingly, the cell X may start detecting the PRACH preamble before the cell X starts transmitting the DL signal. Therefore, on the premise that the timing relationship between the trigger information of the random access process (such as the PDCCH order or the activation signaling of the cell X) and the transmission of the PRACH preamble is satisfied, the UE may not need to wait for the periodically-allocated PRACH channel resources and may transmit the PRACH preamble as quickly as possible. Therefore, the UL synchronization may be rapidly obtained. Therefore, the UE may transmit the UL data and control information. The transmission of the UL CSI information is a necessitate condition that the cell X may optimally allocate the DL channel resources.

The newly-added PRACH resources may be configured in implicit mode. For instance, with a certain principle, the UE may determine that extra PRACH channel resources may be dedicatedly allocated in p UL sub-frames after the sub-frame n, in which the indication for activating the cell X is received. For instance, when the scheduling relationship of the UL Grant is taken into consideration, p may be larger than 4. If the UE only can transmit the UL signal in the sub-frame (n+t0) according to the definition of the conventional LTE CA system, p may be larger than or equal to t0.

In another example, the newly-added PRACH resources may be configured in an explicit mode. For instance, when the cell X is configured as the Scell or the DC serving cell and the periodically-allocated PRACH resources are configured, it may be configured that the extra PRACH channel may be configured in which sub-frame of the cell X. In another example, the indication information indicating that which sub-frame may include the configured extra PRACH channel may be added to the PDCCH order sent to the UE. For instance, it may be assumed that the sub-frame, at which the PDCCH order may be located, is the sub-frame m and the UE may transmit the PRACH preamble in the sub-frame (m+k2), k2 may be larger than or equal to 6. It may be indicated in the PDCCH order that the extra PRACH channel resources are allocated to which sub-frame or sub-frames from the sub-frame (m+6). In another example, it may be assumed that the random access process may be simultaneously triggered with the signaling for activating the cell X. Therefore, the indication information indicating that which sub-frame includes the configured extra PRACH channel may be added to the activation signaling.

The sub-frame position of the allocated extra PRACH channel in time may be described above. The frequency position may be independently configured with the high-layer signaling. In another example, the whole bandwidth may be divided into multiple PRACH channels taking 6 PRBs as a unit by default and may be used for transmitting the PRACH preamble. In another example, it may be configured that at most 6 PRACH channels on the whole bandwidth may be used for transmitting the PRACH preamble. In another example, it may be configured the only one PRACH channel may be used for transmitting the PRACH preamble.

Here, when the UE receives the indication information for activating the cell X, it may be possible that the cell X may be just opened or may have been opened and serving the UL transmission of some other UEs. The above mentioned method for allocating the extra PRACH resources may be applied to a situation that the cell is just opened, but may not be applied to a situation that the cell X may have been serving other UEs. Then, a piece of indication information, such as one bit, may be added to a message (PDCCH order or signaling for activating the cell X) for triggering the random access process of the UE to indicate whether the UE may determine the extra RRACH resources except for the periodically-allocated PRACH resources according to the above method of the present disclosure. In another example, the method for allocating the extra PRACH resources mentioned in above embodiments of the present disclosure not only may be apply to the situation that the cell X is just opened and but also be applied to the situation that the cell X may have been serving other UEs. Then, it may be avoided that the allocated extra PRACH resources and UL transmission of other UEs conflict with each via the UL scheduling of the cell X. With this method, the random access process may be speeded up. Although the allocation of the extra PRACH resources may increase the overhead of the UL resources, the UL and DL transmission efficiency may be enhanced.

Embodiment two

This embodiment may provide a preferred method for measuring the RSRP/RSRQ and CSI information according to the DiS.

In order to effectively transmit the DL control signal and DL data in the cell X, the CSI information of the DL link is necessary. In the conventional LTE CA scheme, it may be assumed that if the UE receives indication information for activating a Scell in the sub-frame n, the UE only may start feeding back the CSI information from the sub-frame (n+t0). For instance, in the LTE CA system, t0 may equal to 8. In practice, the feedback of the CSI information may rely on some other factors, such as whether the UL synchronization is implemented, whether there are available period CSI feedback channel resources, time delay for triggering an aperiodic CSI report and time delay from a moment that the cell X receives the CSI report of the UE to a moment that the DL data of the UE may be scheduled with the CSI report, etc. Therefore, according to the conventional LTE CA scheme, generally speaking, there may be no CSI information of the DL channel for supporting the DL transmission of the UE in more than ten ms after the eNB transmits the indication information for activating the Scell, which may affect the performance of the DL transmission based on the cell ON/OFF scheme.

In practice, in order to support the ON/OFF operation of the cell X, the DiS may be introduced. The DiS may have the function of the DL synchronization and the RSRP and RSRQ of the cell X may be measured. The present disclosure further discloses designing the DiS to make the UE support the CSI measurement based on the DiS. Figure 5 is a flow chart illustrating a method for measuring the CSI information of the cell X based on the DiS in accordance with various embodiments of the present disclosure.

The present disclosure discloses that when the UE measures the RSRP/RSRQ of the cell X based on the DiS, the CSI information of the cell X may be simultaneously measured and both the RSRP/RSRQ and the CSI information may be reported to the activated serving cell (such as the Pcell, marco-cell) of the UE. The RSRP/RSRQ and the CSI information of the report may be used as a basis for the network to determine whether to open the cell X to serve the UE. Since compared with the RSRP/RSRQ, the CSI information may more accurately reflect whether the cell X is suitable for serving the UE, so that the ON/OFF of the cell X may be optimally processed. The present disclosure may not make any limitation on how to determine whether the cell X needs to be opened or closed by the network according to the RSRP/RSRQ and the CSI information. Here, generally speaking, in order to save power and reduce the interference, in a situation that the cell X is in the OFF state, the DiS may be transmitted in a long period. The transmission of each period may not occupy too many time-frequency resources. Therefore, the CSI information measured based on the DiS generally may reflect a long-term characteristic, such as a long-term Channel Quality Indicator (CQI) characteristic of the DL link. Furthermore, in general, the DiS may be used for measuring the CQI characteristic of the bandwidth. Here, the present disclosure may not limit that the DiS only may be used for measuring the long-term bandwidth CQI of the DL link. In practice, the sub-band CQI of the DL link may be measured based on the DiS depending on the design of the DiS and the transmission period. When the cell X transmits the DiS on multiple antenna ports, the UE even may measure a precoding matrix for MIMO transmission based on the DiS. As an exceptional case, since the RSRQ may reflect useful signals and interference characteristic. The RSRQ may have some similarities with the CSI. The UE may report a measurement to a serving cell, which may have been activated, to indicate the RSRQ characteristic and CSI characteristic by defining a measurement method of an interference signal.

Then, when the network decides to open the cell X, the network may take the CSI information of the UE as a parameter and send the CSI information of the UE to the cell X. Therefore, the cell X may obtain information about the UE channel state. The CSI may be the long-term andwideband CSI information. However, the cell X may refer to the CSI to perform DL scheduling for the UE, which may avoid blind DL data transmission. In another example, relying on the design of the DiS, the CSI information may be relatively accurate information. Therefore, the cell X may perform accurate DL scheduling for the UE. Because of the useful CSI information, the cell X may effectively schedule the DL transmission of the UE without waiting until the sub-frame (n+t0). Here, it may be defined that the UE may start detecting the PDCCH and PDSCH of the Scell from the sub-frame n, in which the indication information for activating the cell X may be received. In another example, it may be defined that the UE may start detecting the PDCCH and PDSCH of the Scell from the next sub-frame of the sub-frame n, in which the indication information for activating the cell X may be received, i.e. the sub-frame (n+1). In another example, taking other timing requirements into consideration, it may be defined that the UE may start detecting the PDCCH and PDSCH of the Scell from the sub-frame (n+T), which is T sub-frames time delay from the sub-frame n, in which the indication information for activating the cell X may be received. T may be larger than 0 and less than or equal to t0. The time delay T may provide some preparation time for the PDCCH and PDSCH transmitted between the cell X and UE.

Then, the UE may accurately measure CSI information of the cell X while the UE receives the PDCCH and PDSCH of the cell X and report the CSI information to the cell X or another serving cell (such as the Pcell, macro-cell) to indirectly report the CSI of the cell X. Therefore, the cell X may accurately and timely schedule the PDCCH and PDSCH of the UE with the CSI information.

The method for measuring the RSRQ and CSI of the present disclosure may be described hereinafter.

In the conventional LTE system, the RSRQ may be defined as a value obtained by RSRP divided by a Received Signal Strength Indication (RSSI). The RSRP may be average energy of Resource Elements (RE)s occupied by the CRS on an OFDM symbol. The RSSI may be defined as total average energy on the OFDM symbol, at which the CRS may be located. That is, in the definition of the RSSI, as for this cell, the RSSI may include the total average energy of the CRS REs on the OFDM symbol, at which the CRS may be located and the data REs in the signal of the cell. As for a neighbor cell, the RSSI may include the total average energy of the CRS REs on the OFDM symbol, at which the CRS may be located and the data REs in the signal of the neighbor cell. However, taking requirements of reliability of the detection of the DiS into consideration, a relative large frequency multiplexing coefficient may need to be configured for the DiS. That is, as for the REs of the DiS transmitted in a cell, generally, the neighbor cell may not transmit any signal on these REs. The advantages of such processing may be that the reliability of the detection of the DiS of the cell may be enhanced. However, such processing may result in that the characteristics of the RSRQ measured based on the DiS may be different from the RSRQ measurement based on the CRS in the conventional LTE system. Therefore, the characteristics of the interference signal cannot be accurately reflected. Different from the DiS, the neighbor cell may transmit data signals on the REs of the CRS transmitted in a cell.

First of all, an embodiment of the present disclosure may provide a method for measuring the RSRQ based on the DiS. According to the above analysis, the OFDM symbol, at which the DiS may be located, may be not suitable for measuring the RSSI. Therefore, an embodiment of the present disclosure may put forward configuring time-frequency resources of the UE for measuring the RSSI with the high-layer signaling. The high-layer signaling may be broadcast or respectively configured for each UE. The time-frequency resources may be configured taking the OFDM symbol as the granularity or may be configured taking the RE as the granularity. For instance, the time-frequency resources for measuring the RSSI may be a periodically-configured OFDM symbol, multiple OFDM symbols, one sub-frame or multiple sub-frames. Here, as for the UE, the OFDM symbols configured with the high-layer signaling for measuring the RSSI only may be other OFDM symbols except for the OFDM symbol allocating the DiS of the UE. In another example, all OFDM symbols in a subframe may be configured, while it is up to eNB implementation to decide whether to configure the OFDM symbol including the DiS for measuring the RSSI. As for one UE, in a sub-frame configured by the high-layer signaling for measuring the RSSI, if the sub-frame includes the DiS, other OFDM symbols except for the OFDM symbol, which may be occupied for allocating the DiS of the UE, may be allocated for measuring the RSSI. In another example, another high-layer signaling may configure that which OFDM symbols cannot be used for measuring the RSSI. For instance, a super set of OFDM symbols occupied by the DiSs of multiple users may be configured and the super set may be recorded as R. It may be configured that other OFDM symbols except for the super set R in the sub-frames for measuring the RSSI may be used for measuring the RSSI. In another example, the UE also may measure the RSSI on all OFDM symbols configured by the high-layer signaling for measuring the RSSI. In another example, the REs for measuring the RSSI only may be allocated to one OFDM symbol, multiple OFDM symbols, one sub-frame or multiple sub-frames in one period. Generally, the period of the time-frequency resources for measuring the RSSI may be the same as a transmission period of the DiS. The time position of the time-frequency resources for measuring the RSSI may be close to that of the DiS. Specifically, the OFDM symbol for measuring the RSSI and the DiS may be located at a same sub-frame. In another example, the OFDM symbol for measuring the RSSI may be located at other sub-frames near the sub-frame, at which the DiS may be located. The sub-frame for measuring the RSSI may be the sub-frame, at which the DiS may be located, or may be another sub-frame near the sub-frame, at which the DiS may be located. Here, when the UE needs to measure the RSRQ of the cell X, a signal may need to be received on the frequency of the cell X. The length of the window of the cell X measured by the UE may include multiple sub-frames. Therefore, the UE may measure the RSRP in a sub-frame in the window based on the DiS and simultaneously measure the RSSI in another sub-frame in the window. Therefore, the UE may measure the RSRP of the cell X based on the DiS and measure the RSSI of the cell X with the time-frequency resources for measuring the RSSI. Therefore, the UE may simultaneously measure the RSRP and the RSSI in a short period of time for receiving the DiS and determine the RSRQ according to the RSRP and RSSI.

In the conventional LTE system, the power of the CRS of the cell and other DL signals may be included in the RSSI measurement value. However, with the above method, when the OFDM symbol, at which the DiS may be located, is not used for measuring the RSSI, i.e. the RSSI measured with the above method does not include any signal of the cell, the result may be that the measurement value of the RSSI obtained with the above method may be different from the RSSI measurement value of the conventional LTE system. The above RSSI measurement value may be corrected according to the DiS-based measurement value RSSI_NODiS of the RSRP, the DiS-based measurement value of the RSSI, the number of the CRS REs and the power of the CRS REs, which are actually measured in the RSSI measurement of the conventional LTE system, so that the RSSI measurement value may be closer to the RSSI measurement value in the conventional LTE system.

Since the power of the CRS RE and the power of the DiS RE may be different, the power difference between the CRS RE and DiS RE may be eliminated via a power ratio p. That is, RSRP_DiS= p·RSRP. The parameter p may be configured with a high-layer signaling or may be obtained by calculation with other parameters. If the power difference is not eliminated, RSRP_DiS= p·RSRP.

The RSSI of the conventional LTE system may be defined as average receiving power of each PRB on the OFDM symbol including the CRS. As for a cell, for which only a CRS port 0 may be configured, there may be two CRS REs on one OFDM symbol of one PRB. Therefore, two times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 2·RSRP_DiS+ RSSI_NODiS. As for the cell configured with the CRS ports 0 and 1 or the cell configured with the CRS ports 0, 1, 2 and 3, there may be four CRS REs on one OFDM symbol of one PRB. Therefore, four times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 4·RSRP_DiS+ RSSI_NODiS.

Another RSSI in the conventional LTE system may be that average reception power of all OFDM symbols in one sub-frame on one PRB may be measured. As for the cell only configured with the CRS port 0, there may be 8 CRS REs on one PRB of a sub-frame. Therefore, 8/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system, Nsym may equal to 14 or 12. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 8·RSRP_DiS/Nsym+ RSSI_NODiS. As for the cell configured with the CRS ports 0 and 1, there may be 16 CRS REs on one PRB of a sub-frame. Therefore, 16/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 16·RSRP_DiS/Nsym+ RSSI_NODiS. As for the cell configured with the CRS ports 0, 1, 2 and 3, there may be 24 CRS REs on one PRB of a sub-frame. Therefore, 24/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 24·RSRP_DiS/Nsym+ RSSI_NODiS.

The above calculation of the RSSI in the conventional LTE system may be performed on the assumption that a general CRS pattern may be configured in the sub-frame. That is, the CRS port 0 may occupy 4 OFDM symbols. If it may be configured that the sub-frame for measuring the RSSI is a Multicast Broadcast Single Frequency Network (MBSFN) sub-frame, since the MBSFN occupies relatively less CRS resources, a correction factor of the RSSI may be different. As for the cell only configured with the CRS port 0, there may be 2 CRS REs on one PRB of a sub-frame. Therefore, 2/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 2·RSRP_DiS/Nsym+ RSSI_NODiS. As for the cell configured with the CRS ports 0 and 1, there may be 4 CRS REs on one PRB of a sub-frame. Therefore, 4/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 4·RSRP_DiS/Nsym+ RSSI_NODiS. As for the cell configured with the CRS ports 0, 1, 2 and 3, there may be 8 CRS REs on one PRB of a sub-frame. Therefore, 8/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 8·RSRP_DiS/Nsym+ RSSI_NODiS.

Furthermore, it may be assumed that a general CRS pattern may be configured in the sub-frame. If the implementation of the UE is that RSSI may be measured in the data area of the sub-frame, for instance, on other OFDM symbols except for the first n OFDM symbols, the RSSI may be corrected according to the actual number of the CRS REs. For instance, it may be assumed that the first two OFDM symbols of the sub-frame may not be used for measuring the RSSI. As for the cell only configured with the CRS port 0, there may be 6 CRS REs on one PRB of a sub-frame. Therefore, 6/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system, Nsym may equal to 14 or 12. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 6·RSRP_DiS/Nsym+ RSSI_NODiS. As for the cell configured with the CRS ports 0 and 1, there may be 12 CRS REs on one PRB of a sub-frame. Therefore, 12/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 12·RSRP_DiS/Nsym+ RSSI_NODiS. As for the cell configured with the CRS ports 0, 1, 2 and 3, there may be 16 CRS REs on one PRB of a sub-frame. Therefore, 16/Nsym times the value of the RSRP may be added to the measurement value of the RSSI in the conventional LTE system. Accordingly, when the measurement is performed based on the DiS, the RSSI may be corrected as 16·RSRP_DiS/Nsym+ RSSI_NODiS.

As for the MBSFN sub-frames, if the UE is implemented in the data area of the sub-frame, for instance, the RSSI may be measured on other OFDM symbols except for the first n OFDM symbols. Since there is no CRS RE in the data area, the value RSSI_NODiS of the RSSI obtained from the above measurement method may be the same as that in the conventional LTE system. Therefore, the value RSSI_NODiS of the RSSI may not need to be corrected.

As mentioned above, weighting factors of the RSRP needed in different situations may be different. Therefore, a weighting factor f may be configured with the high-layer signaling, so that the UE may correct the RSSI according to the configured weighting factor. That is, when the UE performs the measurement based on the DiS, the RSSI may be corrected as f·RSRP_DiS+ RSSI_NODiS.

The above method for correcting the RSSI only may be applied to a situation that the cell X may be in the OFF state and only the DiS may be transmitted. In another example, the cell X may simultaneously in the OFF state and ON state.

Therefore, the UE may measure the RSRP of the cell X based on the DiS and may measure the correction value of the RSSI of the cell X with the time-frequency resources for measuring the RSSI, so that the UE may finish the measurement of correction values of the RSRP and RSSI in a short period of time for receiving the DiS and determine the RSRQ according to the correction values of the RSRP and RSSI. Furthermore, when the current cell is in the ON state, the RSRP of the cell X may be measured based on the DiS. When the RSSI is measured, the average receiving power of the OFDM symbol including the CRS on each PRB may be measured. Therefore, the RSSI measurement may be the same as that in the conventional LTE system and may not need to be corrected. In another example, when the current cell is in the ON state, the RSRP of the cell X may be measured based on the DiS. When the RSSI is measured, the average receiving power of all OFDM symbols including the CRS on each PRB may be measured. Then, since the power of the CRS may have been included in the RSSI measurement, the RSSI measurement may be the same as that in the conventional LTE system and may not need to be corrected. Therefore, the UE may measure the RSRP of the cell X based on the DiS and may measure the RSSI with a method, which may be the same as that in the LTE system, so that the UE may finish the measurement of correction values of the RSRP and RSSI in a short period of time for receiving the DiS and determine the RSRQ according to the correction values of the RSRP and RSSI.

An embodiment of the preset disclosure may further provide a method for measuring the CSI based on the DiS. Here, channel characteristics of DL link characteristics of the UE may be obtained according to DiS-based measurement. As for the measurement of interference characteristics of the DL link characteristics, an embodiment of the present disclosure may provide time-frequency resources of the UE configured with the High-layer signaling for measuring the interference. The high-layer signaling may be broadcast or respectively configured for each UE. In practice, when the cell X is in the OFF state, except for the REs occupied by the DiS of the cell X, all other REs may be used as interference measurement resources. Here, it may be put forward by the present disclosure that the conventional configuration method of the ZP CSI-RS may be reused. That is, the CSI-IM may be configured taking 4 REs as the granularity. In another example, the present disclosure may disclose that in one sub-frame, according to the conventional CRS-RS multiplexing method, more ZP CSI-RS resources may be extended with a Walsh code with the length of 2 in time and the ZP CSI-RS resources of the UE for measuring the interference may be configured with the high-layer signaling. Here, the relationship between the ZP CSI-RS resources and the ZP CSI-RS resources used by the UE for normal DL data transmission may not need to be limited. For instance, it may not need to limit that all ZP CSI-RS must include a virtual ZP CSI-RS with a shorter period. In another example, the present disclosure may disclose that the time-frequency resources of the UE for measuring the interference may adopt a new and periodically-configured RE pattern. In one period, these REs may be configured on one OFDM symbol, multiple OFDM symbols, one sub-frame or multiple sub-frames. For instance, in one sub-frame, the REs occupied by the interference measurement resources may be distributed to the whole sub-frame. Here, all REs in a sub-frame, at which the DiS may be located, may be used for configuring the interference measurement resources or may be used for configuring the interference measurement resources in other sub-frames except for the sub-frame, at which the DiS may be located. In another example, the interference measurement resources only may be configured on other REs except for the REs used for the DiS in the sub-frame, in which the DiS may be located. For instance, it may be applied to that the interference measurement resources may be configured on the sub-frame, at which the DiS may be located. In another example, the present disclosure may disclose that the time-frequency resources of the UE for measuring the interference may be all REs of a periodically-configured OFDM symbol, all REs of multiple OFDM symbols, all REs of a sub-frame, or all REs of all sub-frames. Generally, a period of time-frequency resources for measuring the interference may be the same as a transmission period of the DiS and the time position of the time-frequency resources may be close to that of the DiS, so that the UE may simultaneously finish the measurement of the channel and interference of the CSI in a short period of time for receiving the DiS to obtain complete CSI information.

Embodiment three

This embodiment may provide a preferred implementation mode for speeding up the measurement and reporting the accurate CSI information to the cell X.

In order to effectively transmit the DL control signal and DL data in the cell X, the CSI information of the DL link is necessary. In the conventional LTE CA scheme, it may be assumed that if the UE receives indication information for activating a Scell in the sub-frame n, the UE only may feed back the CSI information from the sub-frame (n+t0). For instance, in the LTE CA system, t0 may equal to 8. In practice, the feedback of the CSI information may rely on some other factors, such as whether the UL synchronization is implemented, whether there are available period CSI feedback channel resources, time delay for triggering an aperiodic CSI report and time delay from a moment that the CSI report of the UE may be received from the cell X to a moment that the DL data of the UE may be scheduled with the CSI report, etc. Therefore, according to the conventional LTE CA scheme, generally speaking, there may be no CSI information of the DL channel for supporting the DL transmission of the UE in more than ten ms after the eNB transmits the indication information for activating the Scell, which may affect the performance of the DL transmission based on the cell ON/OFF scheme.

In practice, in order to support the ON/OFF operation of the cell X, the DiS may be introduced. The DiS may have the function of the DL synchronization. Therefore, after the UE performs the DL synchronization based on the DiS signal, the CSI measurement and report process may be speeded up. A method for processing the CSI measurement and feedback of the UE of the present disclosure may be described hereinafter. According to different design, there may be different modified methods of the CSI measurement and feedback, which may be respectively described hereinafter.

First of all, a method for speeding up the accurate CSI information feedback to the cell X from the UE in the present disclosure may be described hereinafter.

In the first method, it may be assumed that the UE may just start detecting the CRS or Non-Zero Power (NZP) CSI-RS and CSI- Interference Measurement (IM) of the cell X to obtain the accurate CSI feedback information after the UE receives the indication information for activating the cell X and report the accurate CSI feedback information to the cell X. According to the assumption of the current CA, if the UE may receive the indication information for activating the Scell in the sub-frame n, the UE only may report the CSI information as early as in sub-frame (n+t0).The present disclosure may disclose that since the UE has obtained the DL synchronization of the cell X according to the DiS, the UE may start detecting the trigger information of the A-CSI in a sub-frame (n+k1) and may not need to wait until the sub-frame (n+t0), k1 may be less than t0 and larger than or equal to 0. Here, when the k1 is larger than 0, some preparation time for transmitting the PDCCH between the cell X and the UE may be provided. The A-CSI may be triggered with the UL Grant or may be triggered with the DL Grant. Accordingly, a bit for triggering the A-CSI may need to be added to the DL Grant. Therefore, the UE may feed back the A-CSI report in a sub-frame (n+k1+k). Here, the sub-frame (n+k1+k) may be a UL sub-frame. The timing relationship between the UL Grant of the sub-frame (n+k1+k) and the UL sub-frame for transmitting the A-CSI may be the same as that in the conventional LTE system. That is, as for the FDD system, k may equal to 4. As for the TDD system, k may be determined according to a timing relationship of a TDD UL and DL configuration and k may be larger than or equal to 4. Specifically, taking the TDD for example, k1 may equal to 4. A sub-frame for the UE to transmit the A-CSI may be a sub-frame (n+k1+k), i.e. sub-frame (n+8), so that the limitation on UL transmission of the UE in the Scell, which may be just activated, in the conventional CA system may be satisfied. In another example, it may be defined that the UE may feedback the A-CSI report in a sub-frame (max(n+k1+k，n+ t0)), so that the limitation on UL transmission of the UE in the Scell, which may be just activated, in the conventional CA system may be satisfied.

In the second method, it may be assumed that before the UE receives the indication information for activating the cell X, trigger information of the A-CSI for triggering the cell X may be detected. The A-CSI may be triggered with the UL Grant or may be triggered with the DL Grant. With this method, the trigger information of the A-CSI may need to be transmitted in another cell (such as the Pcell), which may have been just activated, of the UE. That is, the transmission of the A-CSI in the cell X may be triggered by a cross-carrier scheduling method. This method may apply to a situation that the cross-carrier scheduling of the UL and DL transmission of the cell X is configured. If it is configured that the cell X is self-scheduled, the A-CSI trigger of the cell X may be specially processed. Specially speaking, all A-CSIs of the cell X may be triggered and transmitted in another activated serving cell (such as Pcell) of the UE. In another example, the trigger information of the A-CSI may be transmitted in another serving cell (such as the Pcell), which may have been activated when the cell X is being activated, while the UE may still detect the trigger information of the A-CSI in the cell X in other moments.

It may be assumed that a sub-frame, in which the UE may detect the trigger information of the A-CSI, may be a sub-frame m. The UE may transmit the A-CSI report in a sub-frame (m+k5). Here, the sub-frame (m+k5) may be a UL sub-frame. Here, although the trigger information of the A-CSI may be transmitted before the UE receives the indication information for activating the cell X, it may be limited that the A-CSI report may be transmitted in the cell X after the UE receives the indication information for activating the cell X. That is, it may be defined that the UE may detect the trigger information of the A-CSI in the sub-frame m. Therefore, the sub-frame (m+k5), in which the UE may transmit the A-CSI report, may be behind the sub-frame n, in which the indication information for activating the cell X may be received. Furthermore, it may be limited that the sub-frame (m+k5), in which the UE may transmit the A-CSI report, may be behind a sub-frame (n+T), i.e. T time delay from the sub-frame n, in which the indication information for activating the Scell may be received. T may be larger than 0ms and less than or equal to t0ms. Here, the time delay T may provide some transition time for the cell X to receive the A-CSI report of the UE.

The third method may be that the A-CSI report of the UE in the cell X may be triggered when the cell X is activated. Here, the indication information of the A-CSI, which is to be fed back by the UE, and time-frequency resources, which are to be occupied by the UE, may be configured with the high-layer signaling. After the UE receives the indication information for activating the cell X, the A-CSI report may be fed back on the configured time-frequency resources. Here, the activation signaling may implicitly indicate that the UE may need to report the A-CSI while the activation signaling indicates the activation of the cell X. In another example, new indication information, such as one bit, may be added to the activation signaling to explicitly indicate whether to trigger the A-CSI report of the UE. In another example, signaling structure of the activated cell X may be modified and the indication information of the to-be-fed back A-CSI and the to-be-occupied time-frequency resources may be added, so that after the UE receives a new signaling for activating the cell X, the UE may measure and report the A-CSI. It may be defined that the UE detects the indication information for activating the cell X in the sub-frame n, the sub-frame, in which the UE may start transmitting the A-CSI, is the sub-frame (n+k6). The sub-frame (n+k6) may be the UL sub-frame. According to the timing relationship of the conventional LTE system, k6 may be larger than or equal to 4. In another example, according to the limitation of the conventional LTE system on the UL transmission of the Scell, which may be just activated, k6 may be defined as larger than or equal to t0.

According to differences of DL transmission modes of the UE, methods for measuring the CSI of the UE may be different. As for a CRS based measurement mode, after the cell X is opened and the CRS is transmitted, the CSI measurement may begin. As for a CSI-RS based measurement mode, only after the cell is opened and both the NZP CSI-RS and CSI-IM configured for the UE emerge, the CSI measurement may be performed. Here, when the configured cell X is a Scell or a DC serving cell, the NZP CSI-RS and CSI-IM allocated to the UE when the cell X is opened may be configured with the high-layer signaling. The NZP CSI-RS and CSI-IM may be allocated according to a certain period. In the conventional LTE system, the minimum period may be 5ms. That is, a process for the UE to measure and report the CSI based on the NZP CSI-RS and CSI-IM is slower than that for measuring the CSI based on the CRS. The method of the present disclosure described hereinafter may put forward how to speed up the process for the UE to measure and report the CSI based on the NZP CSI-RS and CSI-IM.

Since when the cell X is just opened, there may not be accurate CSI information, with which the cell X may transmit DL data in the first several sub-frames, and the efficiency of the DL transmission may not be high. Therefore, although allocated extra NZP CSI-RS and CSI-IM may increase the resource overhead, the DL transmission efficiency may be enhanced as a whole. In order to speed up the measurement performed by the UE based on the NZP CSI-RS and CSI-IM, the present disclosure may disclose that after the cell X is opened, on the basis of configuring the periodically-allocated NZP CSI-RS and CSI-IM resources of the UE, extra NZP CSI-RS and CSI-IM resources may be allocated in the first several sub-frames after the cell X is just opened. Therefore, the measure of the CSI performed by the UE with the extra resources may be speeded up. Therefore, the accurate CSI information may be fed back as quickly as possible. If the DL data is not transmitted in the first several sub-frames after the cell X is just opened, the allocation of extra NZP CSI-RS and CSI-IM resources cannot cause any throughput loss.

Here, if there are other timing requirements, the NZP CSI-RS and CSI-IM resources only may be allocated in a sub-frame after a period of time delay T from a moment that the indication information for activating the cell X is received. T may be larger than 0 and less than or equal to t0. The newly-allocated NZP CSI-RS resources may be allocated in one or multiple sub-frames after the UE receives the indication information for activating the cell X. As for the CSI-IM, the CSI-IM may be allocated in one or multiple sub-frames after the UE receives the indication information for activating the cell X, which may be the same as that of the NZP CSI-RS. In another example, resources of sub-frames before the UE receives the indication information for activating the cell X may be taken as the CSI-IM, which may increase the processing operations of the UE. That is, the UE may need to process the CSI-IM before the indication information for activating the cell X is received, which may cause extra complexity and energy loss. Here, if the UE performs normal DL data transmission on the cell X, two sub-frame sets may be configured and respectively used for reporting the CSI information. Extra NZP CSI-RS and CSI-IM resources may be configured corresponding to the two CSI sub-frame sets.

As for the TDD system, it may be assumed that the first M UL sub-frames after the cell X is just opened may not be available (M< t0). In another method, the cell X may work in the first several sub-frames after the cell X is just opened according to a TDD UL and Dl configuration, in which the proportion of DL sub-frames is greater and work in a normal TDD UL and DL configuration after the accurate CSI information of the UE is obtained. That is, the cell X may work in an Enhanced Interference Mitigation and Traffic Adaptation (eIMTA) mode. Furthermore, in the first several sub-frames of the cell X, the cell X may work according to an all-DL sub-frames mode. The newly-added DL sub-frames only may be used for allocating the NZP CSI-RS and CSI-IM resources. In another example, the newly-added DL sub-frames may be used for simultaneously transmitting the CRS, NZP CSI-RS and CSI-IM resources. In another example, the DL data and DL control signal may be transmitted in these newly-added DL sub-frames according to a normal sub-frame method. With this method, as for the TDD system, the obtaining of accurate DL synchronization of the UE, the feedback of accurate CSI information of the UE and transmission of the DL data may be speeded up.

The newly-added NZP CSI-RS and CSI-IM resources may be configured in an implicit mode. For instance, with a certain principle, the UE may determine a sub-frame, in which the NZP CSI-RS and CSI-IM resources may be located. Extra NZP CSI-RS and CSI-IM resources may be allocated in one sub-frame. For instance, extra NZP CSI-RS and CSI-IM resources may be allocated on a sub-frame, in which the UE may receive the indication information for activating the cell X. In another example, the NZP CSI-RS and CSI-IM resources may be allocated in a next sub-frame of the sub-frame n, in which the UE may receive the indication for activating the cell X, i.e. the sub-frame (n+1). In another example, taking other timing requirements into consideration, the NZP CSI-RS and CSI-IM resources may be allocated in a sub-frame (n+T), which is T sub-frames time delay from the sub-frame n, in which the indication information for activating the cell X may be received. T may be larger than 0 and less than or equal to t0. In another example, extra NZP CSI-RS and CSI-IM resources may be allocated in multiple sub-frames. Here, in one sub-frame, the newly-added resources may be configured according to the RE resource of high layer configured periodically configured NZP CSI-RS and CSI-IM resources.

In another example, the newly-added NZP CSI-RS and CSI-IM resources may be configured in an explicit mode. For instance, when the cell X is configured as the Scell or the DC serving cell and the periodically-allocated NZP CSI-RS and CSI-IM resources are configured, sub-frames, in which extra NZP CSI-RS and CSI-IM resources may be configured when the cell X is just opened, may be configured. In another example, the indication information indicating the configured extra NZP CSI-RS and CSI-IM resources may be added to the DL Grant of the UE. Here, in order to reduce the signaling overhead, the RE resource of the NZP CSI-RS and CSI-IM resources may be configured by high layer signaling, or the RE resource of the periodically configured the NZP CSI-RS and CSI-IM resources by high layer signaling may be reused, so that it only needs to indicate whether there may be extra NZP CSI-RS and CSI-IM resources in the current sub-frame. Therefore, when the cell X is activated, extra NZP CSI-RS and CSI-IM resources may need to be indicated.

The sub-frame position of the extra NZP CSI-RS and CSI-IM resources in time may be described above. The RE position occupied in one sub-frame may be independently configured with the signaling. In another example, same RE resources used as configure the NZP CSI-RS and CSI-IM resources by the high-layer signaling may be reused by default.

Here, when the UE receives the indication information for activating the cell X, it may be possible that the cell X may be just opened or may have been opened and serving the DL transmission of some other UEs. The above mentioned method for allocating extra NZP CSI-RS and CSI-IM resources may be applied to a situation that the cell is just opened, but may not be applied to a situation that the cell X may have been serving other UEs. Then, a piece of indication information, such as one bit, may be added to a message (UL Grant, DL Grant or signaling for activating the cell X) for triggering the A-CSI report of the UE to indicate whether the UE may determine the extra NZP CSI-RS and CSI-IM resources except for the periodically-allocated NZP CSI-RS and CSI-IM resources according to the above method of the present disclosure. In another example, the method for allocating the extra NZP CSI-RS and CSI-IM resources mentioned in above embodiments of the present disclosure not only may be apply to the situation that the cell X is just opened and but also may be applied to the situation that the cell X may have been serving other UEs. The impact of the extra NZP CSI-RS and CSI-IM resources on the UE, which is performing the DL transmission, may need to be taken into consideration.

With the above method, on the basis of the periodically-allocated NZP CSI-RS and CSI-IM resources, extra NZP CSI-RS and CSI-IM resources may be allocated. In order to avoid the impact of these extra NZP CSI-RS and CSI-IM resources on the RE mapping of the PDSCH, in the sub-frame, in which these extra NZP CSI-RS and CSI-IM resources may be allocated, REs that cannot be used for transmitting the PDSCH may be indicated. It may be implicitly obtained that for instance, REs which cannot be used for transmitting the PDSCH may be obtained according to a configuration of ZP CSI-RS in the normal DL transmission. That is, extra ZP CSI-RS may occupy the same RE resources in one sub-frame. This may be implemented with an explicit configuration signaling. For instance, in the sub-frame, in which the extra NZP CSI-RS and CSI-IM resources may be transmitted, REs that cannot be used for transmitting the PDSCH may be configured with the high-layer signaling. The signaling may be broadcast or may be respectively configured for each UE.

The above embodiments describe the methods for fast receiving and transmitting DL data and UL data in the present disclosure. The present disclosure may further provide a terminal device for implementing the methods in the above embodiments. Figure 6 is a diagram illustrating basic structure of the terminal device. As shown in figure 6, the terminal device may include: a DiS reception and DL synchronization unit, a first channel state measurement and reporting unit, a random access unit and a second channel state measurement and reporting unit.

In the terminal device, the DiS reception and DL synchronization unit may be configured to receive a DiS, process DL synchronization according to the DiS or according to the DiS and a Cell-specific Reference Signal (CRS) after a cell X is opened.

The first channel state measurement and reporting unit may be configured to measure Reference Signal Receiving Power (RSRP)/Reference Signal Receiving Quality (RSRQ) and/or Channel State Information (CSI) information of the cell X based on the DiS and report the RSRP/RSRQ and/or CSI information to a serving cell, which is currently working. This unit may measure the RSRP/RSRQ and/or CSI information with the method in embodiment two.

The DL information reception unit may be configured to receive a Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) on the cell X.

The random access unit may be configured to detect trigger information of a random access process on the cell X and execute the random access process. This unit may speed up the random access process with the mode in embodiment one.

The second channel state measurement and reporting unit may be configured to measure and report the CSI information to the cell X. This unit may measure report accurate CSI information with the mode in embodiment three.

It may be seen from the above embodiments of the present disclosure, in the present disclosure, the transition time from the opening of the cell X to the receiving or transmitting of the UL and DL data may be effectively reduced and the ON/OFF operation of the cell may be effectively supported.

The foregoing only describes examples of the present disclosure. The protection scope of the present disclosure, however, is not limited to the above description. Any change or substitution, easily occurring to those skilled in the art, should be covered by the protection scope of the present disclosure.

Claims

A method for receiving and transmitting downlink (DL) and uplink (UL) data of a user equipment (UE), comprising:

processing DL synchronization based on a discovery signal (DiS) or based on the DiS and a cell-specific reference signal (CRS);

measuring at least one of reference signal receiving power (RSRP)/reference signal receiving quality (RSRQ) and channel state information (CSI) of a cell based on the DiS and reporting information related to the at least one of RSRP/RSRQ and CSI to a serving cell, which is currently working;

receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) on the cell, detecting trigger information of a random access process on the cell, executing the random access process, measuring and reporting information related to the CSI to the cell.
The method according to claim 1, further comprising:

obtaining transmitting timing of a physical random access channel (PRACH) preamble in the random access process based on reception timing of the DiS of the cell.
The method according to claim 1, wherein receiving the PDCCH on the cell and detecting the trigger information of the random access process on the cell comprises: receiving the PDCCH on the cell before a sub-frame (n+t0) and detecting the trigger information of the random access process on the cell on the PDCCH,

wherein n is a number of a sub-frame in which the UE detects indication information for activating the cell and t0 is a constant, and wherein t0 equals to 8.
The method according to claim 3, wherein detecting the trigger information of the random access process on the cell on the PDCCH comprises: detecting a PDCCH order from a sub-frame (n+k3), where 0≤k3< t0;

detecting PDCCH order triggerring of the random access process on the cell;

receiving the indication information for activating the cell; and

extracting the trigger information of the random access process from the received indication information for activating the cell.
The method according to claim 4, further comprising

transmitting a PRACH Preamble in the random access process before the UE receives the indication information for activating the cell; or

transmitting the PRACH Preamble after the UE receives the indication information for activating the cell; or

transmitting the PRACH Preamble on the cell after T ms time delay from a sub-frame, in which the indication information for activating the cell is received, where 0≤T<t0.
The method according to claim 1, further comprising:

configuring a physical random access channel (PRACH) resources in the random access process in first N UL sub-frames after the cell is opened or several sub-frames before a sub-frame in which the UE detects indication information for activating the cell, where N<t0 and t0 is a constant, wherein a sub-frame used for the PRACH is configured in an implicit mode or explicit mode.
The method according to claim 6, the explicit mode comprises: configuring that which sub-frames comprise a configured PRACH channel if the cell is opened or indicating that which sub-frames comprise the configured PRACH channel in the trigger if the cell is configured as a Scell or a dual connectivity (DC) serving cell.
The method according to claim 1, wherein measuring the at least one of RSRP/RSRQ and CSI based on the DiS comprises:

measuring the RSRP/RSRQ of the cell and the CSI of the cell based on the DiS, reporting the RSRP/RSRQ and CSI information to the servicing cell; or

reporting a measurement value to the serving cell, to indicate a RSRP/RSRQ characteristic and a CSI characteristic.
The method according to claim 8, wherein measuring the RSRQ of the cell based on the DiS comprises: measuring the RSRP based on the DiS, measuring a received signal strength indication (RSSI) on a time-frequency resource configured with a high-layer signaling for measuring the RSSI and determining the RSRQ based on the measured RSRP and RSSI,

wherein the time-frequency resource for measuring the RSSI comprises one or multiple periodically-configured orthogonal frequency division multiplexing (OFDM) symbols, one or more periodically-configured sub-frames, time-frequency resources periodically configured taking a resource element (RE) as a granularity, and

wherein REs in each period are allocated to one or multiple OFDM symbols or one or multiple sub-frames.
The method according to claim 8, wherein measuring the CSI of the cell based on the DiS comprises: configuring a time-frequency resource of the UE for measuring interference with a high-layer signaling and measuring the CSI on the configured time-frequency resource,

wherein the time-frequency resource for measuring the interference comprises a time-frequency resource for measuring the interference configured with a configuration method of zero power (ZP) ZP CSI-RS, a ZP CSI-RS resource obtained via extension with a CRS-RS multiplexing method in one sub-frame, a periodically-configured self-defined RE pattern, all REs of one periodically-configured OFDM symbol, all REs of multiple OFDM symbols, all REs of a sub-frame or all REs of multiple sub-frames, and

wherein the high-layer signaling indicates ZP CSI-RS resources of the UE for measuring the interference in the ZP CSI-RS resources obtained by the extension.
The method according to claim 1, wherein if the CSI is Aperiodic CSI (A-CSI), measuring and reporting the CSI to the cell comprises: receiving the PDCCH on the cell before a sub-frame (n+t0); detecting trigger information of the A-CSI on the cell on the PDCCH, measuring the CSI; and transmitting an A-CSI report,

wherein the UE is triggered to transmit the A-CSI report on the cell with indication information for activating the cell,

wherein n is a number of a sub-frame in which the UE detects the indication information for activating the cell, and

wherein t0 is a constant.
The method according to claim 11, wherein detecting the trigger information of the A-CSI on the cell on the PDCCH comprises: detecting the trigger information of the A-CSI from a sub-frame (n+k1), where 0≤k1<t0;

detecting the trigger information of the A-CSI on the cell before the indication information for activating the cell is received.
The method according to claim 12, wherein transmitting the A-CSI report comprises:

transmitting the A-CSI report on the cell after the UE receives the indication information for activating the cell; or

transmitting the A-CSI report on the cell after T ms time delay from a sub-frame, in which the indication information for activating the cell is received, where 0≤T<t0.
The method according to claim 1, further comprising:

allocating extra non-zero power (NZP) channel state indication-reference signal (CSI-RS) and channel state indication-interference measurement (CSI-IM) resources except for periodically-allocated NZP CSI-RS and CSI-IM resources in first M sub-frames after the cell is opened if the CSI information of the UE is measured based on a measurement mode of the CSI-RS, where M<t0 and t0 is a constant;

respectively configuring the extra NZP CSI-RS and CSI-IM resources for two CSI sub-frame sets if the UE is configured with the two CSI sub-frame sets and respectively reports the CSI information of a corresponding sub-frame set.
The method according to claim 14, wherein as for a time division duplexing (TDD) system, the cell works in an enhanced interference mitigation and traffic adaptation (eIMTA) mode or works based on DL sub-frames in first N1 UL sub-frames after the cell is opened, where N1<t0,

wherein the extra NZP CSI-RS and CSI-IM resources are configured in an implicit mode and RE resource configuration used for configuring NZP CSI-RS and CSI-IM resources with a high-layer signaling is multiplexed, or the extra NZP CSI-RS and CSI-IM resources are configured in an explicit mode,

wherein the explicit mode comprises: configuring that which sub-frames comprise the extra NZP CSI-RS and CSI-IM resources with a high-layer signaling if the cell is opened or adding indication information of the extra NZP CSI-RS and CSI-IM resources to a DL Grant transmitted to the UE, or indicating configuration information of extra NZP CSI-RS and CSI-IM resources if the cell is activated, or

wherein REs, which cannot be used for transmitting the PDSCH are indicated in a sub-frame, at which the extra NZP CSI-RS and CSI-IM resources are located.
A method for receiving and transmitting downlink (DL) and uplink (UL) data of a network, comprising:

sending a measured channel state information (CSI) to a cell if a user equipment (UE) detects the CSI of the cell based on a discovery signal (DiS), so that the cell schedules a physical downlink shared channel (PDSCH) before a sub-frame (n+t0), where t0 is a constant.
An apparatus adapted to perform the method of one of claims 1-16.