CN104780559A - Method and device for quickly receiving and sending downlink data and uplink data - Google Patents

Abstract

The invention discloses a method for quickly receiving and sending downlink data and uplink data. The method comprises the following steps: UE processing downlink synchronization according to DiS, or DiS and a CRS after a cell X is opened; the UE measuring RSRP/RSRQ and/or CSI information of the cell X based on DiS, and reporting to a service cell currently in work; the UE receiving PDCCH and PDSCH on the cell X, detecting trigger information in a random access process on the cell X, and executing the random access process; the UE measuring and reporting the CSI information. Through the adoption of the method and device disclosed by the invention, the uplink synchronization process of the UE can be accelerated, the UE measurement process and the CSI feedback process are accelerated, required conversion time from the condition that the cell is opened to the condition that the cell is capable of really receiving and sending the uplink data and the downlink data is reduced, thereby effectively supporting the ON/OFF operation of the cell, and improving the system performance.

Description

Method and equipment for rapidly receiving and transmitting downlink data and uplink data

Technical Field

The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for rapidly opening a serving cell and transceiving downlink data and uplink data.

Background

In the 3GPP LTE system, each radio frame is 10ms in length, equally divided into 10 subframes. A downlink Transmission Time Interval (TTI) is defined in a subframe. Fig. 1 is a schematic diagram of a subframe structure. Each downlink subframe comprises two time slots, and each time slot comprises 7 OFDM symbols for the length of a general Cyclic Prefix (CP); for extended CP length, each slot contains 6 OFDM symbols. The resource allocation granularity within a subframe is the physical resource block PRB. One PRB includes 12 consecutive subcarriers in frequency, corresponding to one slot in time. Two PRBs in two slots on the same subcarrier within one subframe are referred to as one PRB pair. Within each PRB pair, each Resource Element (RE) is the smallest unit of time-frequency resources, i.e., one subcarrier in frequency and one OFDM symbol in time. The REs may be respectively used for different functions, e.g., a portion of the REs may be respectively used for transmitting a cell-specific reference signal (CRS), a user-specific demodulation reference signal (DMRS), a channel quality indication reference signal (CSI-RS), and the like.

The first n OFDM symbols of each downlink subframe may be used to transmit downlink control information, including a Physical Downlink Control Channel (PDCCH) and other control information, with n being equal to 0, 1, 2, 3, or 4; the remaining OFDM symbols may be used to transmit PDSCH or enhanced pdcch (epdcch). In the LTE system, the PDCCH carries Downlink Control Information (DCI) for allocating uplink channel resources or downlink channel resources, which are respectively referred to as downlink grant signaling and uplink grant signaling. The authorization signaling of different UEs is sent independently. The downlink authorization signaling and the uplink authorization signaling are respectively and independently sent.

In the LTE system, downlink data is transmitted based on a hybrid automatic repeat request (HARQ) mechanism. In order to support channel adaptation and optimize downlink transmission performance, the UE needs to feed back current Channel State Information (CSI) in the uplink direction. CSI can be further distinguished into channel Rank Indication (RI), coding matrix indication (PMI), Channel Quality Indication (CQI), and the like. According to the definition of a plurality of downlink transmission modes in the LTE system. For example, for the downlink direction, a closed loop Multiple Input Multiple Output (MIMO) transmission mode, an open loop MIMO mode, a transmit diversity transmission mode, etc. are included. The CSI feedback forms are different for different transmission modes.

To further increase the peak transmission rate, LTE systems support Carrier Aggregation (CA). Specifically, the network may configure multiple carriers for a UE, where one is a primary serving cell (Pcell) and the others are secondary serving cells (scells). The initial state of a configured Scell is inactive. The network may activate or deactivate an Scell with indication information in a Control Element (CE) of a Medium Access Control (MAC) when transmitting downlink data. Assuming that the UE activates a configured Scell at subframe n through the MAC CE, the UE can perform general uplink and downlink transmission on the Scell only from subframe n +8, including SRS transmission, CSI feedback, PDCCH detection on the Scell, and the like. In short, after the UE receives the MAC CE activating the Scell, it cannot actually operate on the Scell for at least 8 ms.

For aperiodic CSI (a-CSI) reporting, the fastest case is that the UE receives an uplink scheduling signaling (UL Grant) triggering the a-CSI in subframe n +8, then feeds back the a-CSI information in n +8+ k, where k is greater than or equal to 4, and further after a certain processing delay, the base station can really transmit downlink data by using the information reported by the a-CSI. For uplink transmission, if the Scell uplink is in an out-of-synchronization state, the UE may detect an indication (PDCCH order) triggering the Scell random access procedure at subframe n +8 earliest; then, the UE can send a random access Preamble (Preamble) only in subframe n +8+ k2, where k2 is greater than or equal to 6; then, the UE can obtain uplink synchronization after receiving random access response information (RAR), thereby performing uplink transmission.

In a further evolution version of the LTE system, an important technical point is further enhancement of small cells. Specifically, 3 scenes may be included. The first scenario is the case where macro cells and small cells are deployed on the same frequency, where the macro cells provide coverage and hot spot enhancement is accomplished by densely deploying small cells, where the small cells may be divided into one or more cell clusters. The second scenario is where the macro cell and the small cell are deployed at different frequencies, and similarly, the macro cell provides coverage and hot spot enhancement is accomplished by densely deploying the small cells, where the small cells may be divided into one or more cell clusters. Here, a cluster of small cells may be deployed in the same building. The third scenario is a case of only deploying small cells, the small cells may be divided into one or more cell clusters, the small cells are densely deployed in each cluster, and a cluster of small cells may be deployed in the same building. In the three scenarios, a common problem is that, because the small cells are deployed more densely and interfere with each other greatly, interference from the macro cell is also present in the first scenario, and therefore, how to handle the interference problem in the small cell scenario is to be solved.

From the discussion in the current RAN1, a promising technique is to turn on one small cell only when needed and turn off those small cells that are not needed, thereby reducing the overall network interference level and thus increasing the system user throughput. This technique is hereinafter referred to as small cell ON/OFF. This is because, in the existing LTE system, even if one small cell does not serve any UE, the small cell still needs to transmit the CRS, and the CRS needs to be transmitted with relatively high power, thereby causing interference to other small cells actually serving the UE. The small cells which do not serve the UE currently are closed, so that CRS is not transmitted, interference to the adjacent small cells which actually serve the UE is reduced, and system performance is improved. The unnecessary small cells are shut down, and the energy loss of the base station equipment is also reduced. However, the turning OFF and turning ON of small cells takes time, and if the processing time delay is too large, the small cell ON/OFF technology may not have any benefit, and even cause the system performance to be reduced.

In order to effectively support small cell ON/OFF operations and reduce the impact of the transition time for turning OFF and ON small cells, in the current RAN1 discussion, a Discovery reference Signal (ds) is introduced. As shown in fig. 2, on the premise of power saving, for the small cell in the OFF condition, its channel state, such as Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ), can still be measured, so that the network can select the optimal small cell according to the traffic distribution and channel state of the UE, and quickly utilize this small cell to serve uplink and downlink data transmission of the UE. Further, after the cell has switched to the ON state, it is still possible to continue transmitting DiS. To avoid a relatively large delay caused by cell handover, in the current discussion of RAN1, a CA technology or a Dual Connectivity (Dual Connectivity) technology may be utilized, that is, the UE maintains a connection established on one cell (generally, a macro cell), so as to avoid a handover procedure; meanwhile, the transmission enhancement uplink and downlink transmission is realized by using the CA or the dual-connection technology and using another cell, and the switching time required by the UE is shorter because the switching is not needed. As shown in fig. 3, taking CA as an example, when the small cell is in the OFF state, the UE may still perform Radio Resource Management (RRM) related measurement based ON DiS and report another cell (e.g., a macro cell) to which it is connected, and the macro cell may convert the small cell into the ON state and send a Scell activation indication to the UE (denoted as subframe n) according to actual traffic and channel status. In this way, the small cell transitions to the ON state, and the UE may detect the PDCCH of the small cell and report CSI information at subframe n + 8.

The problem to be solved by the invention is to further reduce the influence of the switching time of the small cell ON and OFF by reasonably applying the DiS technology and the CA or dual connection technology, thereby optimizing the ON/OFF performance of the small cell.

Disclosure of Invention

The application discloses a method and equipment for rapidly opening a service cell and receiving and transmitting downlink data and uplink data.

In order to achieve the purpose, the following technical scheme is adopted in the application:

a method for rapidly transceiving downlink data and uplink data comprises the following steps:

the UE processes downlink synchronization according to DiS or according to DiS and CRS after the cell X is opened;

the UE measures the RSRP/RSRQ and/or CSI information of the cell X based on DiS and reports the RSRP/RSRQ and/or CSI information to the currently working serving cell;

the UE receives the PDCCH and the PDSCH on the cell X, detects the trigger information of the random access process on the cell X and executes the random access process; the UE measures and reports CSI information to cell X.

Preferably, the sending timing of the PRACH preamble signal in the random access procedure is obtained based on the receiving timing of DiS of cell X.

Preferably, the receiving, by the UE, the trigger information of the PDCCH on the cell X to detect the random access procedure on the cell X includes: the UE receives a PDCCH on a cell X before an n + t0 subframe, and detects trigger information of a random access process on the cell X on the PDCCH; where n is the subframe number of the indication information that the UE detected the activated cell X, and t0 is a constant.

Preferably, t0 is equal to 8.

Preferably, the trigger information for detecting the random access procedure on the cell X on the PDCCH is: the UE starts to detect the PDCCH order at the subframe n + k3, wherein k3 is more than or equal to 0 and t 0.

Preferably, the trigger information for detecting the random access procedure on the cell X on the PDCCH is: the UE detects trigger information PDCCHorder of a random access process on a cell X before receiving indication information for activating the cell X.

Preferably, the UE sends the PRACH preamble signal in the random access procedure before receiving the subframe of the indication information of activating the cell X; or after receiving the activation indication information of the cell X, the UE sends the PRACH preamble signal on the cell X; or after receiving the activation indication information of the cell X and delaying for T ms, the UE sends the PRACH preamble signal on the cell X, where T is greater than or equal to 0 and less than T < T0.

Preferably, the triggering information for detecting the random access procedure on the cell X includes: and the UE extracts the triggering information of the random access process from the received indication information of the activated cell X.

Preferably, the first N uplink subframes after the cell X is turned on or a plurality of subframes before the cell X activation indication information is received are used to configure the PRACH resource of the random access channel used by the UE in the random access process, where N < t0, and t0 is a constant.

Preferably, the subframe used for PRACH is implicitly or explicitly configured.

Preferably, the explicit configuration mode is as follows: when a cell X is configured to serve as a Scell or a serving cell of dual connectivity, configuring which subframes contain configured PRACH channels when the cell X is just opened; or, which subframes contain configured PRACH channels are indicated in the trigger information.

Preferably, the UE measuring RSRP/RSRQ and CSI information of cell X based on DiS includes:

the UE measures the RSRP/RSRQ of the cell X based on DiS, measures the CSI information of the cell X at the same time, and reports the RSRP/RSRQ and the CSI information to a serving cell which is currently activated by the UE; or,

the UE reports a measurement quantity to the currently activated serving cell, and the measurement quantity is used for indicating the RSRQ characteristic and the CSI characteristic.

Preferably, when the UE measures CSI information of a cell based on DiS, the network sends the measured CSI information to cell X for PDSCH scheduling before n + t0 subframe by cell X; where t0 is a constant.

Preferably, the DiS-based measurement of RSRQ of cell X comprises: measuring RSRP based on DiS, measuring RSSI on a time-frequency resource which is configured by a high-level signaling and used for measuring RSSI, and determining RSRQ according to the measured RSRP and RSSI;

the time-frequency resource for measuring RSSI is as follows: one or more OFDM symbols of a periodic configuration, or one or more subframes of a periodic configuration; or, the RE is allocated on one or more OFDM symbols or one or more subframes in each period.

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

wherein, the time frequency resource for interference measurement is: configuring time-frequency resources for interference measurement by adopting a ZP CSI-RS configuration method; or, expanding in a subframe by adopting a CRS-RS multiplexing method to obtain ZP CSI-RS resources, and indicating the ZP CSI-RS resources for interference measurement of the UE in the expanded ZP CSI-RS resources by using a high-level signaling; or, a user-defined RE pattern configured periodically is adopted; or all REs of one OFDM symbol, or all REs of multiple OFDM symbols, or all REs of one subframe, or all REs of multiple subframes, which are periodically configured.

Preferably, when the CSI information is a-CSI information, the measuring and reporting CSI information to the cell X by the UE includes: the UE receives a PDCCH on a cell X before an n + t0 subframe, detects trigger information of A-CSI on the cell X on the PDCCH, measures the CSI and sends an A-CSI report; where n is the subframe number of the indication information that the UE detected the activated cell X, and t0 is a constant.

Preferably, the triggering information for detecting a-CSI on cell X on the PDCCH includes: the UE starts to detect the trigger information of the A-CSI at the subframe n + k1, wherein k1 is more than or equal to 0 and t 0.

Preferably, the triggering information for detecting a-CSI on cell X on the PDCCH includes: before receiving the indication information for activating the cell X, the UE detects A-CSI trigger information of the cell X.

Preferably, after receiving the activation indication information of the cell X, the UE sends an a-CSI report on the cell X; or after receiving the activation indication information of the cell X and delaying for T ms, the UE sends an A-CSI report on the cell X, wherein T is more than or equal to 0 and less than T0.

Preferably, the indication information of the activated cell X is used to trigger the reporting of the a-CSI report of the UE in the cell X.

Preferably, when the CSI information measurement of the UE is a CSI-RS based measurement mode, additional NZP CSI-RS and CSI-IM resources for CSI measurement are allocated in the first M subframes after cell X is turned on, except for the periodically allocated NZP CSI-RS and CSI-IM resources, where M < t0, t0 is a constant.

Preferably, when the UE configures two CSI subframe sets and respectively reports CSI information of the corresponding subframe sets, the two CSI subframe sets are respectively configured with the additional NZP CSI-RS and CSI-IM resources.

Preferably, for a TDD system, the first N1 uplink subframes just opened by cell X, where cell X operates in the enhanced interference coordination and service adaptation eIMTA mode or operates according to a downlink subframe; wherein N1< t 0.

Preferably, the additional NZP CSI-RS and CSI-IM resources are implicitly configured and RE resource configurations of periodic NZP CSI-RS and CSI-IM resources configured by higher layer signaling are multiplexed; alternatively, the additional NZP CSI-RS and CSI-IM resources are explicitly configured.

Preferably, the explicit configuration mode is as follows: configuring which subframes contain additionally configured NZP CSI-RS and CSI-IM resources when a cell X is just opened by using a high-level signaling; or adding additionally configured indication information of the NZP CSI-RS and CSI-IM resources in the DL Grant sent to the UE; alternatively, configuration information for additional CSI-RS and CSI-IM resources is indicated while cell X is activated.

Preferably, on the subframe where the additional NZP CSI-RS and CSI-IM resources are located, it is indicated which REs cannot be used for PDSCH transmission.

A terminal device for rapidly transceiving downlink data and uplink data, comprising: DiS receiving and descending synchronization unit, first channel state measurement and reporting unit, random access unit, second channel state measurement and reporting unit; wherein,

the DiS receiving and downlink synchronizing unit is used for receiving DiS and processing downlink synchronization according to DiS or according to DiS and CRS after cell X is turned on;

the first channel state measuring and reporting unit is used for measuring RSRP/RSRQ and/or CSI information of the cell X based on DiS and reporting to a currently working serving cell;

the downlink information receiving unit is used for receiving a PDCCH and a PDSCH on a cell X;

the random access unit is used for detecting the trigger information of the random access process on the cell X and executing the random access process;

and the second channel state measuring and reporting unit is used for measuring and reporting CSI information to the cell X.

The method and the equipment can accelerate the uplink synchronization process of the UE, accelerate the process of UE measurement and CSI feedback, and reduce the conversion time from opening the cell to really receiving and transmitting the uplink and downlink data of the UE, thereby effectively supporting the ON/OFF operation of the cell and improving the system performance.

Drawings

FIG. 1 is a schematic diagram of a subframe structure;

FIG. 2 is a transmission diagram of DiS;

fig. 3 is a flow chart of cell activation based on DiS;

FIG. 4 is a flow chart of the present invention;

fig. 5 is a flow chart of measurement reporting CSI based on DiS;

fig. 6 is a schematic diagram of a basic structure of a terminal device in the present application.

Detailed Description

For the purpose of making the objects, technical means and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings.

For clarity of description, a cell performing a cell ON/OFF operation will be referred to as a cell X hereinafter. ON the basis of the fact that the ON/OFF operation of the cell X is effectively supported, the conversion time from opening of the cell X to the real transceiving of the uplink and downlink data of the UE needs to be reduced, the base station is provided with DiS for measuring the cell X by the UE, the uplink synchronization process of the UE is accelerated, the processes of measuring and feeding back CSI by the UE are accelerated, and therefore the UE can start to transceive the uplink and downlink data at a higher speed after the cell X is opened.

Fig. 4 shows a basic flow chart of the method of the present invention.

Step 401: the UE may obtain downlink synchronization for cell X according to DiS of cell X; or, after the cell X is turned on, the UE may further enhance the downlink synchronization accuracy according to the CRS after the cell X is turned on.

Basically, the downlink synchronization of the cell X can be directly obtained according to DiS of the cell X, so that the UE can realize the downlink synchronization as soon as possible and accelerate the sending of the downlink control information. Further, after the cell X is turned on, the downlink synchronization accuracy may be further enhanced according to the CRS after the cell X is turned on.

Step 402: the UE measures RSRP/RSRQ and/or CSI information of cell X based on DiS of cell X and reports to the currently operating serving cell.

The UE can measure RSRP/RSRQ and/or CSI information according to DiS before the cell X is not activated, and reports the RSRP/RSRQ and/or CSI information, so that the network can determine whether the cell X needs to be opened or not according to the RSRP/RSRQ and/or CSI information and the like reported by each UE. Preferably, if the CSI information is measured and reported before the cell X is not activated, on the one hand, the reported CSI information may be used as a reference for the network to decide whether to open the cell X; on the other hand, compared with the current CSI information measurement based on the CRS, the status information of the downlink channel can be obtained earlier, so that the downlink data can be transmitted within a shorter time after the cell X is turned on.

Step 403: the UE receives the PDCCH and the PDSCH on the cell X, detects the trigger information of the random access process on the cell X and executes the random access process; the UE measures and reports accurate CSI information.

The mode of performing random access and CSI information reporting in this step may be performed by using an existing mode. However, in step 401, DiS based on cell X accelerates the speed of obtaining downlink synchronization by the UE, so preferably, in this step, the UE can receive the PDCCH and PDSCH on cell X earlier, trigger the random access process earlier, achieve uplink synchronization between the UE and cell X as soon as possible, and further perform measurement and reporting of CSI information in advance.

The flow shown in fig. 4 ends up so far. As can be seen from the flow of fig. 4, the ON/OFF operation of the cell X can be effectively supported by the following three processes: firstly, downlink synchronization is carried out in advance according to DiS, and the uplink synchronization process of the UE is accelerated; secondly, measuring CSI information of the cell X according to DiS before the cell X is not activated; and thirdly, performing downlink synchronization in advance according to DiS, and accelerating the process of UE measurement and accurate CSI information feedback. The following describes the specific implementation of the above three processing modes by three preferred embodiments.

Example one

This embodiment describes a preferred implementation manner for speeding up the UE uplink synchronization process.

In order to transmit uplink control signals and uplink data in cell X, the UE first needs to complete uplink synchronization with cell X. In the existing CA mechanism, assuming that an Scell and a Pcell belong to different Timing Advance Groups (TAGs), a random access procedure of a UE on the Scell needs to be triggered to acquire uplink synchronization. Assuming that the UE receives the indication information for activating the Scell in subframe n, the UE starts to detect the PDCCH order triggering the random access procedure of the Scell from subframe n + t 0; then, the UE can send a random access Preamble (Preamble) at least in the subframe n + t0+ k2, where k2 is greater than or equal to 6, and PRACH resources are allocated on the subframe n + t0+ k 2; then, the UE can obtain uplink synchronization after receiving random access response information (RAR). Where t0 is a constant. For example, in an LTE CA system, t0 is equal to 8. Assuming that the delay of RAR is 3ms, in the above mechanism, the UE cannot perform uplink transmission at least 17ms after the indication information activating the Scell is sent from the base station, including that the CSI information of the downlink channel cannot be fed back, which inevitably affects the performance of uplink and downlink transmission based ON the operation of the cell ON/OFF mechanism.

In fact, since DiS of cell X is periodically transmitted with a certain long period, based on this DiS, the UE can determine the receiving timing of the downlink signal of cell X, i.e. complete downlink synchronization. Based on this reception timing, the UE may derive the transmission timing of the PRACH preamble signal. For example, the reception timing of DiS is used as the transmission timing of the PRACH preamble signal. Depending on the design of DiS, the accuracy of downlink receiving timing obtained by UE according to DiS may be different correspondingly, but generally, PRACH preamble signal may be sent according to the downlink timing, because cell X may send TA command to adjust UE uplink transmission after receiving PRACH preamble signal, so that UE obtains accurate uplink transmission timing. The method of the present invention for handling the random access procedure of cell X is described below. Depending on the design, there may be different degrees of ways to improve the random access procedure, which are described separately below.

First, the method of the present invention for accelerating the triggering of the random access procedure will be described.

The first method is to assume that the UE still starts checking the trigger information PDCCH order of the random access procedure after receiving the indication information of activating cell X. Note that the UE detects indication information of the activated cell X in subframe n. According to the current assumption of CA, the UE may already transmit information such as SRS and CSI report at time n + t0, and such UE may also necessarily transmit PRACH preamble. Therefore, the present invention proposes that, since the UE has obtained downlink synchronization of cell X according to DiS through the process of step 401, the UE may not need to wait until n + t0 subframes, but may start detecting PDCCH order at n + k3 subframes, where k3 is less than t0 and greater than or equal to 0. Here, k3 is determined according to some other factors that actually limit UE activation of Scell, and k3 may provide some transition time for cell X to receive PRACH preamble of UE. In this way, the starting subframe number of the PRACH preamble signal that the UE may transmit is n + k3+ k2, and the subframe n + k3+ k2 includes the configured PRACH channel resources. Based on the timing relationship between the existing PDCCH order and the PRACH preamble signal, that is, k2 is greater than or equal to 6. In particular, k3 may be equal to 2, and the starting subframe number of the PRACH preamble signal that the UE may transmit is n + k3+ k2= n +8, thereby satisfying the limitation of uplink transmission on the Scell that is just activated by the UE in the existing CA system. Alternatively, because the UE will not have other uplink transmissions on cell X immediately before cell X is turned on and uplink synchronized, it may be considered to configure the UE to respond to the PDCCH order faster, i.e., the minimum value of k2 may be less than 6.

The second method is to assume that the UE can detect the PDCCH order triggering the random access procedure of cell X before receiving the indication information activating cell X. With this approach, the PDCCH order needs to be sent on another serving cell (e.g. Pcell) of the UE that has been activated, i.e. the transmission of the PRACH preamble signal on cell X is triggered by a cross-carrier scheduling method. This method is directly applicable to the case where uplink and downlink transmission based on cross-carrier scheduling cell X is configured. If the cell X is configured to adopt self-scheduling, the PDCCH order of the cell X needs to be specially processed. Specifically, all pdcchs for this cell X are transmitted on another activated serving cell (e.g., Pcell) of the UE; it is also possible that only while cell X is activated, PDCCH order is transmitted in another serving cell already in active state, while at other times the UE still detects PDCCH order on cell X.

Assuming that the subframe in which the UE detects the PDCCH order is subframe m, the UE transmits a PRACH preamble signal in subframe m + k4, where the subframe m + k4 is configured with a PRACH channel. If the timing relationship of transmitting the PRACH preamble from the PDCCH order to the UE in the existing LTE CA is still used, k4 is equal to or greater than 6.

Here, the sequence of the subframe in which the UE transmits the PRACH preamble signal and the subframe in which the UE receives the indication information of the activated cell X may not be limited. Thus, when the subframe m + k4 of the PRACH preamble signal sent by the UE is earlier than the subframe n of the indication information that the UE receives the activation cell X, the network needs to configure the cell X to enter such a state before sending the activation indication of the cell X to the UE: although cell X does not send any signal in the downlink direction, cell X has already started to detect the random access preamble signal. For RAR, it needs to be sent after cell X is activated.

Alternatively, another timing relationship is that the UE is restricted to send the PRACH preamble signal on cell X after receiving the activation indication information of cell X. Note that UE detects PDCCH order in subframe m, then subframe m + k4 where UE sends PRACH preamble signal must be after subframe n where indication information to activate cell X is received. Further, the subframe m + k4 for UE to transmit PRACH preamble signal must be superposed by a delay T after the subframe n receiving the indication information of activating cell X, where T is greater than 0ms but less than or equal to T0 ms. The delay T here may provide some preparation time for cell X to receive the PRACH preamble of the UE.

The third method is to trigger the random access procedure of the UE while activating cell X. Here, the parameters of the PRACH preamble signal of the UE may be configured by a high-level signaling, and after the UE receives the indication information for activating the cell X, the random access procedure may be initiated according to the configured parameters of the PRACH preamble signal. In the method, the trigger information of the random access process can be directly carried in the activation indication information of the cell X without adopting the PDCCH order. Specifically, the activation signaling may indicate that the UE needs to start a random access procedure of the cell X implicitly while indicating that the cell X is activated; alternatively, new indication information, for example, 1 bit, may be added in the activation signaling to explicitly indicate whether to trigger the UE random access procedure in cell X. Or, the signaling structure of the activated cell X may be modified, and necessary configuration parameters for the PRACH preamble signal are added, so that the UE may initiate the random access procedure after receiving the new signaling of the activated cell X. Keeping in mind that the UE detects the indication information of activating the cell X in the subframe n, the starting subframe number at which the UE can send the PRACH preamble signal is n + k2, and the subframe n + k2 includes the configured PRACH channel resources. Based on the timing relationship between the existing PDCCHorder and the PRACH preamble, that is, k2 is greater than or equal to 6. Alternatively, if there is a restriction on uplink transmission on the Scell just activated with the existing LTE system, it may be defined that k2 is greater than or equal to t 0.

In the above description of the random access procedure, the timing relationship from the reception of the trigger information of the random access procedure (for example, the activation instruction of the PDCCH order or the cell X) to the transmission of the PRACH preamble signal by the UE is defined, and the PRACH preamble signal is required to be transmitted in a subframe where the PRACH channel resource is configured. The subframe configured with PRACH channel resources may be configured to the UE through a higher layer signaling, for example, when the cell X is configured as Scell or a serving cell with dual connectivity is configured, the configuration information of the PRACH channel resources when the cell X is turned on is configured through the configuration signaling. According to the mechanism of the existing LTE CA system, the configured PRACH resources are allocated according to a certain period. Thus, on the premise of satisfying the timing relationship from the activation command of the PDCCHorder or the cell X to the transmission of the PRACH preamble, the UE must wait for the periodically allocated PRACH channel resources to transmit the random access preamble.

A method of increasing allocated PRACH channel resources is described below. In fact, since cell X is just turned on, it is generally not able to transmit uplink data in its first several uplink subframes. For example, because uplink data transmission generally requires first detecting the UL Grant and then delaying for at least 4 ms to really transmit uplink data, at least the first 4 uplink subframes after cell X is turned on are idle. Or, if the UE can transmit the uplink signal only in the subframe n + t0 according to the limitation of the existing LTE CA system, the cell X is idle in the first t0 uplink subframes after being turned on. The invention provides that on the basis of periodically allocating PRACH resources to the UE, additional PRACH resources are allocated, so that the UE can more quickly send PRACH preamble signals. Here, the additional PRACH resources may be configured in the first several subframes after the UE receives the cell X activation indication information. For example, the additional PRACH resources may be allocated within the above-mentioned idle subframe after cell X is turned on; or, the configuration may be performed in more subframes including the idle subframe after the cell X is turned on; or, assuming that the cell X is already open and is serving uplink transmission of some other UEs when the UE receives the activation indication information of the cell X, additional PRACH resources may still be allocated near the subframe where the UE receives the activation indication information. Here, there may be other timing requirements, for example, the PRACH channel may be allocated only in a subframe after receiving the activation indication information of cell X and delaying for a period of time T, where T is greater than 0 and less than or equal to T0. Alternatively, if the cells X have activated the uplink reception operation before starting to transmit the downlink signal, the uplink resources of the uplink subframe before the cells X start to transmit the downlink signal may also be used to allocate PRACH channel resources, and accordingly, the cells X may detect the PRACH preamble signal before starting to transmit the downlink signal. Thus, on the premise of satisfying the timing relationship from the trigger information (e.g. PDCCHorder or activation instruction of cell X) in the random access process to the transmission of the PRACH preamble, the UE may transmit the PRACH preamble as fast as possible without waiting for the PRACH channel resources allocated periodically, thereby obtaining uplink synchronization quickly. Therefore, the UE can transmit uplink data and control information, where the transmission of the uplink CSI information is a necessary condition for allocating downlink channel resources that can be optimized by the cell X.

These newly added PRACH resources may be implicitly configured. For example, using a certain principle, the UE may determine that the UE may be additionally dedicated to allocating PRACH channel resources in p uplink subframes after receiving the subframe n of the activated cell X. For example, when the scheduling relationship of UL Grant is considered, p is equal to or greater than 4; if the UE can transmit uplink signals only in the subframe n + t0 according to the definition of the existing LTE CA system, p is greater than or equal to t 0.

Alternatively, these newly added PRACH resources may be explicitly configured. For example, when configuring the cell X as Scell or a serving cell with dual connectivity, and configuring PRACH resources allocated in a configuration period, it is configured that PRACH channels may be additionally configured in subframes of the cell X. Or, adding indication information indicating that the subframes contain the additionally configured PRACH channels in the PDCCH order sent to the UE. For example, assuming that the subframe in which the PDCCH order is located is m, and assuming that the UE transmits the PRACH preamble on the subframe m + k2, where k2 is greater than or equal to 6, it may be indicated in the PDCCH order which subframe or subframes from the subframe m +6 are allocated with the additional PRACH channel resources. Alternatively, if the signaling of the active cell X is used to trigger the random access procedure at the same time, the activation signaling may be added with indication information indicating that those subframes contain the additionally configured PRACH channels.

The above description focuses on the subframe location of the additionally allocated PRACH channel in time, and the frequency location of the additionally allocated PRACH channel may be configured independently by using a higher layer signaling, or may be also divided into multiple PRACH channels by default in units of 6 PRBs and may all be used for transmission of the PRACH preamble, or configure that at most 6 PRACH channels on the entire bandwidth may be used for transmission of the PRACH preamble, or configure that only one PRACH channel in one subframe is available for transmission of the PRACH preamble.

Here, when the UE receives the activation indication information of cell X, cell X may be either just turned on or may be turned on and serving uplink transmissions of some other UEs. The method of allocating additional PRACH resources proposed above in the present invention may be used only in the case where cell X has just been turned on, and not in the case where cell X is already serving other UEs. In this case, an indication message, for example, 1 bit, may be added to a message (PDCCH order or signaling activating cell X) triggering a random access procedure of the UE to indicate whether the UE may determine additional PRACH resources other than the periodically allocated PRACH resources according to the above method of the present invention. Alternatively, the method of allocating additional PRACH resources proposed above in the present invention may be used both in the case where cell X has just been turned on and in the case where cell X is already serving other UEs. At this time, collision between the additionally allocated PRACH resource and uplink transmission of other UEs can be avoided through uplink scheduling of cell X. By adopting the method, the random access process is accelerated, and the uplink and downlink transmission efficiency can be improved on the whole by allocating the additional PRACH resources although the uplink resource overhead is increased.

Example two

In this example a preferred implementation of measuring RSRP/RSRQ and CSI information according to DiS is given.

In order to effectively transmit downlink control signals and downlink data in cell X, CSI information of the downlink is a necessary condition. In the existing LTE CA mechanism, assuming that the UE receives indication information for activating one Scell in subframe n, the UE starts to feed back CSI information only from subframe n + t 0. For example, in an LTE CA system, t0 is equal to 8. Actually, the CSI information feedback depends on other factors, such as whether uplink synchronization is performed currently, whether available periodic CSI feedback channel resources exist, a time delay for triggering an aperiodic CSI report, a time delay from CSI report received from the cell X to downlink data that can schedule the UE using the CSI report, and the like. Thus, according to the existing LTE CA mechanism, generally, there is no CSI information of a downlink channel to support downlink transmission of the UE within more than ten ms after the indication information activating the Scell is transmitted from the base station, which inevitably affects the performance of downlink transmission based ON the cell ON/OFF mechanism.

In practice, DiS was introduced in order to support the ON/OFF operation of cell X. DiS has the function of downlink synchronization, and can also measure the RSRP and RSRQ of the cell X. The invention further proposes that DiS is designed to support UE DiS based CSI measurements. Fig. 5 shows a basic flow chart of measuring CSI information of cell X based on DiS in the present invention.

The invention proposes that when measuring the RSRP/RSRQ of the cell X based on DiS, the UE simultaneously measures the CSI information of the cell X and reports the RSRP/RSRQ and the CSI information together to a serving cell (e.g. Pcell, macro cell) which the UE has currently activated. The reported RSRP/RSRQ and CSI information can be used as a basis for a network to judge whether the UE served by the cell X needs to be opened or not, so that the ON/OFF of the cell X can be processed more optimally, and after all, the CSI information more accurately reflects whether the cell X is suitable for serving the UE than the RSRP/RSRQ. The invention does not limit how the network determines whether the cell X needs to be switched on and off by combining the RSRP/RSRQ and the CSI information. Here, generally, in order to achieve the power saving and interference reduction functions, in the case that the cell X is in the OFF state, DiS is transmitted in a long period, and time-frequency resources occupied by each period transmission are not too much, so CSI information measured based on DiS generally embodies long-term characteristics of the downlink, such as long-term Channel Quality (CQI) characteristics, and generally DiS is used for measuring wideband CQI characteristics. Here, the present invention is not limited, and only the long-term wideband CQI of the downlink can be measured based on DiS. Indeed, depending on the design and transmission period of DiS, the sub-band CQI for the downlink may be measured based on DiS; when one cell X sends DiS on multiple antenna ports, the UE can measure the precoding matrix for MIMO transmission even on the downlink based on DiS. As a special example, because RSRQ itself is also a characteristic that embodies useful signals and interference, it has a certain similarity with CSI, and by defining a measurement method of interference signals, it may also be that the UE reports a measurement quantity to a currently activated serving cell to indicate both RSRQ characteristics and CSI characteristics.

Next, when the network decides to open cell X, the network may send CSI information of the UE as a parameter to cell X, so that cell X obtains information about the channel state of the UE. The CSI here can be long-term and wideband CSI information, but it provides a reference for cell X to downlink scheduling of UE anyway, avoiding blind downlink data transmission. Alternatively, depending on the design at DiS, the CSI information may already be relatively accurate information, so that cell X may directly perform relatively accurate downlink scheduling for this UE. Because of this already available CSI information, cell X does not need to wait until subframe n + t0 to schedule the UE's downlink transmission more efficiently. Here, it may be defined that the UE starts to detect the PDCCH and PDSCH of the Scell from the subframe n where the activation indication information of the cell X is received; or, the UE may be defined to start detecting the PDCCH and PDSCH of the Scell from a subframe next to the subframe n where the activation indication information of the cell X is received, that is, the subframe n + 1; or, considering other timing requirements, it may be defined that the UE detects the PDCCH and PDSCH of the Scell from subframe n where the activation indication information of cell X is received and after delaying for T subframes, that is, subframe n + T, where T is greater than 0 and less than or equal to T0. The delay T here may provide some preparation time for transmitting PDCCH and PDSCH between cell X and UE.

Next, while receiving the PDCCH and PDSCH of the cell X, the UE may also measure accurate CSI information of the cell X and report the CSI information to the cell X, or report the CSI information to another serving cell (e.g., Pcell, macro cell), so as to indirectly report the CSI of the cell X; in this way, cell X may schedule the PDCCH and PDSCH of the UE with more accurate and timely CSI information.

The method of the present invention for measuring RSRQ and CSI is described below.

In existing LTE systems, RSRQ is defined as RSRP divided by RSSI. Wherein, RSRP is the average energy of REs occupied by CRS on OFDM symbol where CRS is located, and RSSI is defined as the total average energy on OFDM symbol where CRS is located. That is, in the definition of RSSI, for the local cell, it contains the total average energy of CRS RE and data RE on the OFDM symbol where CRS is located in the signal of the local cell; for the adjacent cell, the total average energy of the CRS RE and the data RE on the OFDM symbol where the CRS is located in the adjacent cell signal is contained. However, in consideration of the detection reliability requirement of DiS, DiS generally requires a relatively large frequency reuse factor. That is, on REs that one cell transmits DiS, its neighboring cells typically do not transmit any signals on these REs. This has the advantage of increasing the detection reliability of DiS of the cell, but it also results in that the characteristics of the RSRQ based on DiS measurements are different from those of the CRS based RSRQ measurements in the existing LTE system, and thus cannot actually embody the characteristics of the interfering signal. Unlike DiS, neighboring cells may transmit data signals on REs where one cell transmits CRS.

The invention firstly provides an DiS-based RSRQ measuring method. Since, according to the above analysis, the OFDM symbol where DiS is located is not suitable for measuring RSSI, the present invention proposes to configure the time-frequency resources of the UE for measuring RSSI with higher layer signaling. This higher layer signaling may be broadcast or may be configured for each UE. The time-frequency resource may be configured with OFDM symbols as granularity, or with RE as granularity. For example, the time-frequency resource for measuring RSSI may be one OFDM symbol, or a plurality of OFDM symbols, or one subframe, or a plurality of subframes configured periodically. Here, for a UE, the OFDM symbol configured by the higher layer signaling for RSSI measurement may only be other OFDM symbols except the OFDM symbol where DiS is allocated to the UE; alternatively, all OFDM symbols in a subframe may be available, but depending on the base station implementation whether the OFDM symbol containing DiS is configured for RSSI measurement. For one UE, in the subframe configured by the higher layer signaling for RSSI measurement, if DiS is contained in the subframe, it may be that other OFDM symbols besides the OFDM symbol occupied by DiS that allocates the UE may be used for RSSI; or configuring which OFDM symbols in the subframe cannot be used for measuring RSSI by using another higher layer signaling, for example, configuring a superset of OFDM symbols occupied by DiS of multiple users, denoted as R, and then other OFDM symbols in the subframe configured for RSSI measurement except for the set R may be used for RSSI measurement; alternatively, the UE may measure RSSI on all OFDM symbols of the subframe configured for RSSI measurement by higher layer signaling. Alternatively, the REs for measuring the RSSI may be allocated only on one OFDM symbol, or on a plurality of OFDM symbols, or on one subframe, or on a plurality of subframes in one period. The period of the time-frequency resource for measuring RSSI may be generally the same as the transmission period of DiS, which is located close to DiS. Specifically, the OFDM symbol for RSSI measurement may be located in the same subframe as DiS, or located in another subframe near the subframe in which DiS is located; the subframe for RSSI measurement may be DiS or other subframes near DiS. Here, when the UE needs to measure RSRQ of cell X, which needs to receive signals on the frequency of cell X, the length of the window in which the UE measures cell X may include a plurality of subframes, so that the UE may measure RSRP on the basis of DiS on one subframe within the window while measuring RSSI on another subframe within the window. In this way, the UE measures RSRP of the cell X based on DiS, and measures RSSI of the cell X using time-frequency resources for measuring RSSI, so that the UE can simultaneously complete measurement of RSRP and RSSI in a short time of receiving DiS, and then determine RSRQ according to the RSRP and RSSI.

In the conventional LTE system, the power of CRS and other downlink signals of the cell is also included in the RSSI measurement value, but with the above method, when the OFDM symbol where DiS is located is not used for measuring RSSI, that is, the RSSI measured by the above method does not include the RSSI measurement valueIncluding any signal of the own cell, which results in a deviation of the RSSI measured by the above method from the RSSI measurement value of the existing LTE system. According to DiS-based RSRP measurement value RSRP and RSSI measurement value RSSI_NODiSThe RSSI measurement value may be corrected to be closer to the RSSI measurement value of the existing LTE system according to the number of CRS REs and the power of CRS REs actually measured in the RSSI measurement of the existing LTE system.

Since the power of CRS RE and the power of DiS RE may be different, they may be corrected by the power ratio p of CRS RE and DiS RE, i.e., RSRP_DiS＝_pRSRP. The parameter p may be configured using higher layer signaling or may be calculated using other parameters. If this power difference is not corrected, then RSRP_DiS＝RSRP。

RSSI of one existing LTE system is defined as the average received power per PRB over OFDM symbols containing CRS. For a cell only configured with CRS port 0, there are two CRS REs on one OFDM symbol of one PRB, so that twice the value of RSRP is superimposed on the RSSI measurement value of the existing LTE system. Accordingly, based on DiS measurements, RSSI may be corrected to 2 RSRP_DiS+RSSI_NODiS. For cells configured with CRS ports 0 and 1, or cells configured with CRS ports 0, 1, 2, and 3, there are four CRS REs on one OFDM symbol of one PRB, so that the RSSI measurement value of the existing LTE system is superimposed with 4 times of the RSRP value. Accordingly, based on the DiS measurement, RSSI may be corrected to 4 RSRP_DiS+RSSI_NODiS。

The RSSI of another existing LTE system is to measure the average received power of all OFDM symbols of one subframe over one PRB. For a cell only configured with a CRS port 0, 8 CRS REs are located on one PRB of a subframe, so that an RSRP value 8/Nsym times is superimposed on an RSSI measurement value of the existing LTE system, and Nsym is equal to 14 or 12. Accordingly, based on the DiS measurement, RSSI may be corrected to 8 RSRP_DiS/Ns_ym+RSSI_NODiS. For the cell configured with CRS port 0 and CRS port 1, there are 16 CRS REs on one PRB of the subframe, so the RSSI of the existing LTE systemThe measurement values are superimposed with values of RSRP 16/Nsym times. Accordingly, based on the DiS measurement, the RSSI may be corrected to 16 RSRP_DiS/Ns_ym+RSSI_NODiS. For cells configured with CRS ports 0, 1, 2 and 3, 24 CRS REs are available on one PRB of a subframe, so that a RSRP value 24/Nsym times is superimposed on an RSSI measurement value of the existing LTE system. Accordingly, based on the DiS measurement, the RSSI can be corrected to 24 RSRP_DiS/Nsym+RSSI_NODiS。

The above calculation of RSSI of the existing LTE system assumes that a general CRS pattern is configured in a subframe, i.e., CRS port 0 occupies 4 OFDM symbols. If the subframe configured to measure the RSSI is an MBSFN subframe, the CRS resource occupation of the MBSFN is less, and the correction factor of the RSSI is different. For a cell only configured with a CRS port 0, 2 CRS REs are available on one PRB of a subframe, so that a 2/Nsym RSRP value is superimposed on an RSSI measurement value of the existing LTE system. Accordingly, based on DiS measurements, RSSI may be corrected to 2 RSRP_DiS/Nsym+RSSI_NODiS. For the cell configured with CRS port 0 and CRS port 1, there are 4 CRS REs on one PRB of the subframe, so the RSSI measurement value of the existing LTE system is superimposed with the RSRP value of 4/Nsym times. Accordingly, based on the DiS measurement, RSSI may be corrected to 4 RSRP_DiS/N_sym+RSSI_NODiS. For cells configured with CRS ports 0, 1, 2 and 3, there are 8 CRS REs on one PRB of a subframe, so the RSSI measurement value of the existing LTE system is superimposed with 8/Nsym times RSRP value. Accordingly, based on the DiS measurement, RSSI may be corrected to 8 RSRP_DiS/Nsym+RSSI_NODiS。

In addition, assuming that a general CRS pattern is configured in the subframe, if the UE is implemented to measure the RSSI in the data region of the subframe, for example, in OFDM symbols other than the first n OFDM symbols, the RSSI may be corrected according to the number of CRS REs actually present. For example, assume that the first 2 OFDM symbols of a subframe are not used for measuring RSSI. For a cell only configured with CRS port 0, there are 6 CRS REs on one PRB of a subframe, so that a RSRP value 6Nsym times is superimposed on an RSSI measurement value of the existing LTE system, and Nsym is equal to 14 or 12.Accordingly, based on the DiS measurement, RSSI may be corrected to 6 RSRP_DiS/N_sym+RSSI_NODiS. For the cell configured with CRS port 0 and CRS port 1, there are 12 CRS REs on one PRB of the subframe, so the RSSI measurement value of the existing LTE system is superimposed with the RSRP value of 12/Nsym times. Accordingly, based on the DiS measurement, RSSI may be corrected to 12 RSRP_DiS/Nsym+RSSI_NODiS. For cells configured with CRS ports 0, 1, 2 and 3, there are 16 CRS REs on one PRB of a subframe, so that an RSRP value 16Nsym times is superimposed on an RSSI measurement value of the existing LTE system. Accordingly, based on the DiS measurement, the RSSI may be corrected to 16 RSRP_DiS/Nsym+RSSI_NODiS。

For MBSFN subframes, if the UE implements that RSSI is measured on the data region of the subframe, e.g., OFDM symbols other than the first n OFDM symbols removed, because CRS REs are not present in the data region, RSSI, which is the value of RSSI measured in the above method_NODiSConsistent with existing LTE systems, so no correction is required.

As described above, the weighting factors required for RSRP are different in different situations, so a weighting factor f may be configured by higher layer signaling, so that the UE may modify the RSSI according to the configured weighting factor f, i.e. the RSSI may be modified to f · RSRP when the UE is measured based on DiS_DiS+RSSI_NODiS。

The above method of correcting RSSI may be used only when cell X is currently in the OFF state and thus transmits only DiS, or may be used when cell X is both OFF and ON.

Thus, the UE measures the RSRP of the cell X based on DiS, and measures the correction value of the RSSI of the cell X by using the time-frequency resource for measuring the RSSI, so that the UE can simultaneously complete the measurement of the correction value of the RSRP and the RSSI within a short time of receiving DiS, and then determines the RSRQ according to the RSRP and the RSSI. In addition, when the current cell is in the ON state, the RSRP of the cell X is measured based ON DiS, and when the RSSI is measured, the average received power per PRB ON the OFDM symbol containing the CRS is still measured, so that the RSSI measurement is consistent with that of the existing LTE system, and thus no correction is needed. Or when the current cell is in the ON state, based ON DiS to measure the RSRP of the cell X, when measuring the RSSI, the average received power of all OFDM symbols of a subframe ON one PRB is still measured, and at this time, the power of the CRS is already included in the RSSI measurement, so that the RSSI measurement is consistent with that of the existing LTE system, and no correction is needed. In this way, the UE measures RSRP of the cell X based on DiS, and measures RSSI by a method consistent with the existing LTE system, so that the UE can simultaneously complete measurement of the modified values of RSRP and RSSI within a short time of receiving DiS, and then determine RSRQ according to the RSRP and the RSSI.

The invention also provides a CSI measuring method based on DiS. Here, the channel part of the downlink characteristics of the UE may be based on DiS measurements. For the measurement of the interference part of the downlink characteristics, the invention proposes to configure the time-frequency resources of the UE for interference measurement with higher layer signaling. This higher layer signaling may be broadcast or configured separately for each UE. In fact, when cell X is in the OFF state, all other REs except the REs occupied by DiS of cell X can be used as interference measurement resources. Here, the present invention proposes that the existing configuration method of ZP CSI-RS can still be multiplexed, i.e. CSI-IM is configured with 4 REs as granularity. Or, the invention proposes that more ZP CSI-RS resources can be extended in one subframe according to the existing CRS-RS multiplexing method, i.e., Walsh codes with length 2 are used in time, and ZP CSI-RS resources for interference measurement of the UE are configured by using higher layer signaling. Here, there is no need to limit the relationship between the ZP CSI-RS resource and the ZP CSI-RS resource when the UE performs normal downlink data transmission, for example, there is no need to limit that all ZP CSI-RSs must be included in the same virtual ZP CSI-RS resource with a shorter period. Or, the present invention proposes that the time-frequency resource for interference measurement of the UE may adopt a new RE pattern configured periodically, and in one period, the REs are configured on one OFDM symbol, or on multiple OFDM symbols, or on one subframe, or on multiple subframes. For example, in one subframe, the REs occupied by the interference measurement resources are scattered into the whole subframe. Here, all REs in the subframe in which DiS is located may be used to configure the interference measurement resource, which may be used in the case of configuring the interference measurement resource in other subframes than the subframe in which DiS is located; alternatively, the interference measurement resource may be configured only on other REs except for the REs available for DiS in the subframe where DiS is located, for example, in the case where the interference measurement resource is configured on the subframe where DiS is located. Or, the time-frequency resource for interference measurement of the UE may be all REs of one OFDM symbol, or all REs of multiple OFDM symbols, or all REs of one subframe, or all REs of multiple subframes, which are periodically configured. The time-frequency resource period for interference measurement may be generally the same as the transmission period of DiS, and its time position is close to DiS, so that the UE can complete the measurement of the channel part and the interference part of CSI at the same time in a short time of receiving DiS, thereby obtaining complete CSI information.

EXAMPLE III

This embodiment provides a preferred implementation manner for speeding up measurement and reporting accurate CSI information to cell X.

In order to effectively transmit downlink control signals and downlink data in cell X, CSI information of the downlink is a necessary condition. In the existing LTE CA mechanism, assuming that the UE receives indication information for activating one Scell in subframe n, the UE starts to feed back CSI information only from subframe n + t 0. For example, in an LTE CA system, t0 is equal to 8. Actually, the CSI information feedback depends on other factors, such as whether uplink synchronization is currently performed, whether available periodic CQI feedback channel resources exist, a time delay for triggering an aperiodic CSI report, a time delay from CSI report received from the cell X to downlink data that can schedule the UE using the CSI report, and the like. Thus, according to the existing LTE CA mechanism, generally, there is no CSI information of a downlink channel to support downlink transmission of the UE within more than ten ms after the indication information activating the Scell is transmitted from the base station, which inevitably affects the performance of downlink transmission based ON the cell ON/OFF mechanism.

In practice, to support the ON/OFF operation of cell X, an DiS signal is introduced. DiS signals have the function of downlink synchronization, so that the process of CSI measurement and reporting can be accelerated after the UE performs downlink synchronization according to DiS signals. The following describes a method of the present invention for handling CSI measurement and feedback of a UE. There may be different degrees of CSI measurement and feedback improvement depending on the design, described separately below.

First, the method for accelerating accurate CSI information feedback from a UE to a cell X according to the present invention will be described.

The first method is to assume that the UE starts to measure the CRS or NZP CSI-RS and CSI-IM of the cell X to obtain accurate CSI feedback information and report the accurate CSI feedback information to the cell X after receiving the indication information for activating the cell X. According to the current assumption of LTE CA, if it is remembered that the UE receives the indication information for activating Scell in subframe n, the UE can report CSI information only at the earliest time n + t 0. The invention proposes that, because the UE has already obtained the downlink synchronization of cell X according to DiS, the UE may not need to wait until n + t0, but may start detecting the trigger information of a-CSI at n + k 1. k1 is less than t0 and equal to or greater than 0. Here, when k1 is greater than 0, some preparation time may be provided for transmitting PDCCH between cell X and UE. The a-CSI may be triggered by using UL Grant or DL Grant, and accordingly, bits for triggering the a-CSI need to be added to the DL Grant. In this way, the UE may feed back an a-CSI report at subframe n + k1+ k. Here, subframe n + k1+ k is an uplink subframe, and the timing relationship between the UL Grant and the uplink subframe for transmitting a-CSI may be consistent with that of the existing LTE system, i.e., for an FDD system, k is equal to 4; for a TDD system, k is determined according to the timing relation of TDD uplink and downlink configuration, and k is more than or equal to 4. Particularly, taking FDD as an example, where k1 may be equal to 4, the subframe where the UE transmits the aperiodic a-CSI is n + k1+ k = n +8, so that the restriction of uplink transmission on the Scell that is just activated by the UE in the existing CA system is satisfied. Alternatively, it may be defined that the UE feeds back the a-CSI report in the subframe max (n + k1+ k, n + t 0), so as to satisfy the limitation of the existing CA system on uplink transmission of the UE on the Scell just activated.

The second method is to assume that the UE can detect the a-CSI trigger information triggering cell X before receiving the indication information activating cell X. The a-CSI may use UL Grant trigger and may also use DL Grant trigger. With this approach, a-CSI trigger information needs to be sent on another serving cell (e.g., Pcell) of the UE that has been activated, i.e., a cross-carrier scheduling approach is used to trigger transmission of a-CSI on cell X. This method is directly applicable to the case of configuring cross-carrier based scheduling of uplink and downlink transmissions for cell X. If cell X is configured to employ self-scheduling, its a-CSI trigger needs to be specially processed. Specifically, all a-CSI triggers for this cell X may be sent on another already activated serving cell (e.g., Pcell) of the UE; it is also possible that only when cell X is activated, the a-CSI trigger information is sent in another serving cell already in the activated state, and at other times the UE still detects the a-CSI trigger information on cell X.

Assuming that the subframe in which the UE detects the A-CSI trigger information is a subframe m, the UE sends an A-CSI report in a subframe m + k5, where the subframe m + k5 is an uplink subframe. Here, although the a-CSI trigger information may be sent before the UE receives the indication information for activating cell X, the UE may be restricted from sending the a-CSI report on cell X after receiving the indication information for activating cell X. I.e. keeping in mind that the UE detects a-CSI trigger information in subframe m, subframe m + k5 where the UE sends an a-CSI report must be after subframe n where indication information of activated cell X is received. Further, the subframe m + k5 for UE to send a-CSI report must be superposed by a delay T after the subframe n of the indication information for activating Scell is received, where T is greater than 0ms but less than or equal to T0 ms. The delay T here may provide some switching time for cell X to receive the UE a-CSI report.

The third method is to trigger the UE a-CSI report in cell X while activating cell X. Here, the indication information of the a-CSI to be fed back by the UE and the time-frequency resource to be occupied may be configured by using a higher layer signaling, and after the UE receives the indication information of the activated cell X, the a-CSI report may be fed back on the configured time-frequency resource. Here, the activation signaling may indicate that the UE needs to report a-CSI implicitly while indicating cell X activation; alternatively, new indication information, for example, 1 bit, may be added in the activation signaling to explicitly indicate whether to trigger the a-CSI report of the UE. Or, the signaling structure of the activated cell X may be modified, and the indication information of the a-CSI to be fed back and the time-frequency resources to be occupied are added, so that the UE may measure and report the a-CSI after receiving the new signaling of the activated cell X. Keeping in mind that the UE detects the indication information of the activated cell X in the subframe n, the starting subframe number at which the UE can send the a-CSI is n + k6, the subframe n + k6 is an uplink subframe, and k6 is greater than or equal to 4 according to the timing relationship of the existing LTE system. Alternatively, if there is a restriction on uplink transmission on the Scell just activated with the existing LTE system, it may be defined that k6 is greater than or equal to t 0.

According to the difference of the downlink transmission mode of the UE, the CSI measuring method of the UE is different. For the measurement mode based on the CRS, after a cell X is opened and transmits the CRS, CSI measurement can be started; for the CSI-RS based measurement mode, CSI measurement is possible only when the cell is opened and the NZP CSI-RS and CSI-IM configured for the UE are both present. Here, when the cell X is configured as Scell or one serving cell of dual connectivity, the NZP CSI-RS and CSI-IM allocated to the UE when the cell X is opened are configured through a high layer configuration signaling. The NZP CSI-RS and the CSI-IM are distributed according to a certain period, and in the existing LTE system, the minimum period is 5 ms. That is, the process of UE measuring and reporting CSI based on NZP CSI-RS and CSI-IM is generally slower than CRS based CSI measurement. The method described below of the present invention proposes how to speed up UE measurements and reporting based on NZP CSI-RS and CSI-IM.

Since the CSI information does not accurately support downlink data transmission in the first several downlink subframes of the cell X when the cell X is just turned on, downlink transmission efficiency is not high. Therefore, allocating additional NZP CSI-RS and CSI-IM may increase downlink transmission efficiency as a whole, although increasing resource overhead. In order to accelerate the measurement of the UE based on the NZP CSI-RS and the CSI-IM, the invention provides that after a cell X is opened, additional NZP CSI-RS and CSI-IM resources are distributed in the first subframes after the cell X is opened on the basis of the configuration of the NZP CSI-RS and CSI-IM resources periodically distributed by the UE. The UE can thus speed up the CSI measurement using these additional resources, thereby feeding back accurate CSI information as quickly as possible. If downlink data is not sent in the first few downlink subframes just opened by the cell X, allocating additional NZP CSI-RS and CSI-IM does not bring any downlink throughput loss.

Here, if there are other timing requirements, the NZP CSI-RS and CSI-IM resources may be allocated only on the subframe after receiving the activation indication information of the cell X and delaying for a period of time T. Here, T is greater than 0 and equal to or less than T0. Here, the newly allocated NZP CSI-RS is allocated on one or more subframes after the UE receives the activation indication information of cell X. For CSI-IM, the CSI-IM can be consistent with NZP CSI-RS and is distributed in one or more subframes after the UE receives the activation indication information of the cell X; alternatively, the resource of the subframe before the UE receives the activation indication information of cell X may be used as CSI-IM, but this increases the processing of the UE, i.e. CSI-IM must be processed before the activation indication information of cell X is received, which causes additional complexity and energy loss. Here, if two subframe sets are configured and CSI information is reported respectively when the UE transmits normal downlink data on the cell X, additional NZP CSI-RS and CSI-IM resources may be configured respectively corresponding to the two CSI subframe sets.

For TDD system, assuming that M uplink subframes just before cell X is turned on are unavailable (M < t 0), one method is to make the first several subframes just before cell X is turned on work according to a TDD uplink and downlink configuration with a larger downlink subframe ratio, and after obtaining accurate CSI information of UE, switch back to normal TDD uplink and downlink configuration, that is, cell X works in enhanced interference coordination and service adaptation (eIMTA) mode. Further, the first several subframes of the cell X may operate in a mode of full downlink subframes. The newly added downlink subframes can be only used for allocating NZP CSI-RS and CSI-IM resources; or, the CRS, NZP CSI-RS and CSI-IM resources can be transmitted simultaneously in the newly added downlink subframes; or, the downlink data and the downlink control signal may also be sent in these newly added downlink subframes according to the method of the normal subframe. By adopting the method, the UE can be accelerated to obtain accurate downlink synchronization, the UE can be accelerated to feed back accurate CSI information and the transmission of downlink data can be accelerated for a TDD system.

These newly added NZP CSI-RS and CSI-IM resources may be implicitly configured. For example, the UE may determine subframes where NZP CSI-RS and CSI-IM resources are located, using a certain principle. The resource allocation method may be additionally allocated to NZP CSI-RS and CSI-IM resources in only one subframe, for example, the additional NZP CSI-RS and CSI-IM resources may be allocated to a subframe n where the UE receives the activation indication information of the cell X; or, additional NZP CSI-RS and CSI-IM resources may be allocated to a subframe next to the subframe n where the UE receives the activation indication information of the cell X, that is, the subframe n + 1; or, considering other timing requirements, the additional NZP CSI-RS and CSI-IM resources may be allocated on subframe n + T after the UE receives subframe n where the activation indication information of cell X is located and delays by T subframes, where T is greater than 0 and less than or equal to T0. Or, the number of the NZP CSI-RS and CSI-IM resources additionally allocated in a plurality of subframes may be the same. Here, in one subframe, the newly added resource may be an RE resource configuration multiplexing periodic NZP CSI-RS and CSI-IM resources of a higher layer signaling configuration.

Alternatively, these newly added NZP CSI-RS and CSI-IM resources may be explicitly configured. For example, when the cell X is configured as a Scell, or one serving cell with dual connectivity is configured with the NZP CSI-RS and CSI-IM resources allocated periodically, the NZP CSI-RS and CSI-IM resources may be additionally configured in subframes when the cell X is just opened. Or adding indication information indicating the additionally configured NZP CSI-RS and CSI-IM resources in the DL Grant sent to the UE. Here, in order to reduce signaling overhead, the RE resource configuration of the NZP CSI-RS and CSI-IM resources may be configured by using higher layer signaling, or the RE resource configuration of the periodic NZP CSI-RS and CSI-IM resources configured by multiplexing the higher layer signaling, so that it is only necessary to indicate whether the additionally allocated NZP CSI-RS and CSI-IM resources exist in the current subframe. Alternatively, the mechanism for activating one cell is changed so that the configuration information of additional CSI-RS and CSI-IM resources is indicated while cell X is activated.

The above description focuses on the subframe positions of the additionally allocated NZP CSI-RS and CSI-IM resources in time, and the RE positions occupied by the additionally allocated NZP CSI-RS and CSI-IM resources in one subframe may be configured independently by signaling, or may be the default RE resources that are the same as those adopted by the NZP CSI-RS and CSI-IM resources configured by higher layer signaling.

Here, when the UE receives the activation indication information of cell X, cell X may be either just turned on or may be turned on and serving downlink transmission of some other UEs. The method of allocating additional NZP CSI-RS and CSI-IM resources proposed above in the present invention may be used only in the case where cell X has just been turned on, and not in the case where cell X is already serving other UEs. At this time, an indication information, for example, 1 bit, may be added to a message (UL Grant, DL Grant, or signaling of activated cell X) triggering an a-CSI report of the UE to indicate whether the UE may determine additional NZP CSI-RS and CSI-IM resources in addition to the periodically allocated NZP CSI-RS and CSI-IM resources according to the above method of the present invention. Alternatively, the method of allocating additional NZP CSI-RS and CSI-IM resources proposed above in the present invention can be used both in the case where cell X has just been opened and in the case where cell X is already serving other UEs. At this time, the influence of these additionally allocated NZP CSI-RS and CSI-IM resources on other downlink-transmitting UEs needs to be considered.

By adopting the method, on the basis of the periodical NZP CSI-RS and CSI-IM resources, additional NZP CSI-RS and CSI-IM resources are allocated. To avoid the impact of these additional resources on the RE mapping of PDSCH, on these subframes where NZP CSI-RS and CSI-IM resources are additionally allocated, it is necessary to indicate which REs cannot be used for PDSCH transmission. This may be implicitly obtained, for example, which REs cannot be used for PDSCH transmission are obtained according to the configuration of ZP CSI-RS in normal downlink transmission, i.e. additionally configured ZP CSI-RS occupy the same RE resource in one subframe. This may also be achieved using explicit configuration signaling, e.g. higher layer signaling configuring which REs are not used for PDSCH transmission on those subframes transmitting additional NZP CSI-RS and CSI-IM resources. This signaling may be broadcast or configured separately for each UE.

As described above, this is a specific implementation of the method for rapidly transceiving downlink data and uplink data in the present application. The application also provides a terminal device which can be used for implementing the method. Fig. 6 is a schematic diagram of the basic structure of the apparatus. As shown in fig. 6, the apparatus includes: DiS receiving and descending synchronous unit, the first channel state measuring and reporting unit, the random access unit, the second channel state measuring and reporting unit.

In the above device, the DiS receiving and downlink synchronizing unit is configured to receive DiS, and implement downlink synchronization according to DiS, or process downlink synchronization according to DiS and CRS after cell X is turned on;

and the first channel state measuring and reporting unit is used for measuring the RSRP/RSRQ and/or CSI information of the cell X based on DiS and reporting to the currently working serving cell. The unit may measure RSRP/RSRQ and/or CSI information in the manner of the second embodiment.

And a downlink information receiving unit, configured to receive the PDCCH and the PDSCH on the cell X.

And the random access unit is used for detecting the trigger information of the random access process on the cell X and executing the random access process. The unit may specifically accelerate the random access procedure by using the method in the first embodiment.

And the second channel state measuring and reporting unit is used for measuring and reporting the CSI information to the cell X. The unit can perform measurement and report of accurate CSI information in the manner described in the third embodiment.

As can be seen from the specific implementation of the present application, in the present application, the switching time required for the cell X to transmit and receive uplink and downlink data from the open state is effectively reduced, and the ON/OFF operation of the cell X is more effectively supported.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (27)

1. A method for rapidly transceiving downlink data and uplink data comprises the following steps:

the UE processes downlink synchronization according to DiS or according to DiS and CRS after the cell X is opened;

the UE measures the RSRP/RSRQ and/or CSI information of the cell X based on DiS and reports the RSRP/RSRQ and/or CSI information to the currently working serving cell;

the UE receives the PDCCH and the PDSCH on the cell X, detects the trigger information of the random access process on the cell X and executes the random access process; the UE measures and reports CSI information to cell X.

2. The method of claim 1, wherein a sending timing of the PRACH preamble signal in the random access procedure is obtained based on a receiving timing of DiS of a cell X.

3. The method of claim 1, wherein the receiving, by the UE, the trigger information for the PDCCH on cell X to detect the random access procedure on cell X comprises: the UE receives a PDCCH on a cell X before an n + t0 subframe, and detects trigger information of a random access process on the cell X on the PDCCH; where n is the subframe number of the indication information that the UE detected the activated cell X, and t0 is a constant.

4. A method according to claim 3, characterized in that t0 is equal to 8.

5. The method of claim 4, wherein the trigger information for detecting the random access procedure on cell X on the PDCCH is as follows: the UE starts to detect the PDCCH order at the subframe n + k3, wherein k3 is more than or equal to 0 and t 0.

6. The method of claim 4, wherein the trigger information for detecting the random access procedure on cell X on the PDCCH is as follows: before receiving the indication information for activating the cell X, the UE detects the trigger information PDCCH order of the random access process on the cell X.

7. The method of claim 6, wherein the UE sends the PRACH preamble signal in the random access procedure before receiving the subframe of the indication information of activating cell X; or after receiving the activation indication information of the cell X, the UE sends the PRACH preamble signal on the cell X; or after receiving the activation indication information of the cell X and delaying for T ms, the UE sends the PRACH preamble signal on the cell X, where T is greater than or equal to 0 and less than T < T0.

8. The method of claim 1, wherein the detecting triggering information of the random access procedure on cell X comprises: and the UE extracts the triggering information of the random access process from the received indication information of the activated cell X.

9. The method of claim 1, wherein the first N uplink subframes after cell X is turned on or a number of subframes before cell X activation indication information is received are used for configuring a PRACH resource used by the UE in the random access procedure, where N < t0 and t0 are constants.

10. The method of claim 9, wherein a subframe used for PRACH is implicitly or explicitly configured.

11. The method of claim 10, wherein the explicit configuration is performed by: when a cell X is configured to serve as a Scell or a serving cell of dual connectivity, configuring which subframes contain configured PRACH channels when the cell X is just opened; or, which subframes contain configured PRACH channels are indicated in the trigger information.

12. The method of claim 1, wherein measuring, by the UE, RSRP/RSRQ and CSI information of cell X based on DiS comprises:

the UE measures the RSRP/RSRQ of the cell X based on DiS, measures the CSI information of the cell X at the same time, and reports the RSRP/RSRQ and the CSI information to a serving cell which is currently activated by the UE; or,

the UE reports a measurement quantity to the currently activated serving cell, and the measurement quantity is used for indicating the RSRQ characteristic and the CSI characteristic.

13. The method of claim 1, wherein when the UE measures CSI of a cell based on DiS, the network sends the measured CSI to cell X for PDSCH scheduling of cell X before n + t0 subframe; where t0 is a constant.

14. The method of claim 12, wherein the DiS-based measurement of cell X RSRQ comprises: measuring RSRP based on DiS, measuring RSSI on a time-frequency resource which is configured by a high-level signaling and used for measuring RSSI, and determining RSRQ according to the measured RSRP and RSSI;

the time-frequency resource for measuring RSSI is as follows: one or more OFDM symbols of a periodic configuration, or one or more subframes of a periodic configuration; or, the RE is allocated on one or more OFDM symbols or one or more subframes in each period.

15. The method of claim 12, wherein the DiS-based measurement of CSI information for cell X comprises: configuring a time-frequency resource for interference measurement of the UE by using a high-level signaling, and measuring CSI information on the configured time-frequency resource;

wherein, the time frequency resource for interference measurement is: configuring time-frequency resources for interference measurement by adopting a ZP CSI-RS configuration method; or, expanding in a subframe by adopting a CRS-RS multiplexing method to obtain ZP CSI-RS resources, and indicating the ZP CSI-RS resources for interference measurement of the UE in the expanded ZP CSI-RS resources by using a high-level signaling; or, a user-defined RE pattern configured periodically is adopted; or all REs of one OFDM symbol, or all REs of multiple OFDM symbols, or all REs of one subframe, or all REs of multiple subframes, which are periodically configured.

16. The method of claim 1, wherein when the CSI information is a-CSI information, the UE measuring and reporting CSI information to cell X comprises: the UE receives a PDCCH on a cell X before an n + t0 subframe, detects trigger information of A-CSI on the cell X on the PDCCH, measures the CSI and sends an A-CSI report; where n is the subframe number of the indication information that the UE detected the activated cell X, and t0 is a constant.

17. The method of claim 16, wherein triggering information for detecting a-CSI on cell X on the PDCCH comprises: the UE starts to detect the trigger information of the A-CSI at the subframe n + k1, wherein k1 is more than or equal to 0 and t 0.

18. The method of claim 16, wherein triggering information for detecting a-CSI on cell X on the PDCCH comprises: before receiving the indication information for activating the cell X, the UE detects A-CSI trigger information of the cell X.

19. The method of claim 18, wherein the UE sends an a-CSI report on cell X after receiving the activation indication information of cell X; or after receiving the activation indication information of the cell X and delaying for T ms, the UE sends an A-CSI report on the cell X, wherein T is more than or equal to 0 and less than T0.

20. The method of claim 16, wherein the indication information of activating cell X is used to trigger UE reporting a-CSI report in cell X.

21. The method of claim 1, wherein additional NZP CSI-RS and CSI-IM resources for CSI measurement are allocated in the first M subframes after cell X is turned on, except for periodically allocated NZP CSI-RS and CSI-IM resources, when CSI information measurement of the UE is a CSI-RS based measurement mode, wherein M < t0, t0 is a constant.

22. The method of claim 21, wherein when the UE configures two CSI subframe sets and reports CSI information of the respective subframe sets, the additional NZP CSI-RS and CSI-IM resources are configured for the two CSI subframe sets, respectively.

23. The method of claim 21, wherein for a TDD system, cell X is the first N immediately before being turned on₁A cell X works in an enhanced interference coordination and service self-adaption eIMTA mode or works according to a downlink subframe; wherein N is₁<t0。

24. The method of claim 21, wherein the additional NZP CSI-RS and CSI-IM resources are implicitly configured and RE resource configurations of periodic NZP CSI-RS and CSI-IM resources of a higher layer signaling configuration are multiplexed; alternatively, the additional NZP CSI-RS and CSI-IM resources are explicitly configured.

25. The method of claim 21, wherein the explicit configuration is performed by: configuring which subframes contain additionally configured NZP CSI-RS and CSI-IM resources when a cell X is just opened by using a high-level signaling; or adding additionally configured indication information of the NZP CSI-RS and CSI-IM resources in the DL Grant sent to the UE; alternatively, configuration information for additional CSI-RS and CSI-IM resources is indicated while cell X is activated.

26. The method of claim 21, wherein subframes in which the additional NZP CSI-RS and CSI-IM resources are located indicate which REs are not available for PDSCH transmission.

27. A terminal device for rapidly transceiving downlink data and uplink data, the device comprising: DiS receiving and descending synchronization unit, first channel state measurement and reporting unit, random access unit, second channel state measurement and reporting unit; wherein,

the DiS receiving and downlink synchronizing unit is used for receiving DiS and processing downlink synchronization according to DiS or according to DiS and CRS after cell X is turned on;

the first channel state measuring and reporting unit is used for measuring RSRP/RSRQ and/or CSI information of the cell X based on DiS and reporting to a currently working serving cell;

the downlink information receiving unit is used for receiving a PDCCH and a PDSCH on a cell X;

the random access unit is used for detecting the trigger information of the random access process on the cell X and executing the random access process;

and the second channel state measuring and reporting unit is used for measuring and reporting CSI information to the cell X.