CROSS-REFERENCE TO RELATED APPLICATION

This application is a 35 U.S.C. § 371 U.S. national stage of International Application No. PCT/CN2018/095965 filed on Jul. 17, 2018, which claims priority of Chinese Patent Application No. 201710631718.4 filed on Jul. 28, 2017, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of communication technologies, and in particular, to a downlink control information detecting method, a downlink control information transmitting method, a terminal and a network device.

BACKGROUND

In the Long Term Evolution (LTE) system, and the future fifth generation (5-Generation, hereinafter referred to as 5G) communication system which may be also referred to as New Radio (hereinafter referred to as NR) system, in order to achieve more flexible channel design, terminal blind detection is introduced. Specifically, under the premise of information such as location of physical transmission resource where a location control signaling is located and size of the resource occupied by the location control signaling, the terminal performs tentative detection through various assumptions, until control signaling is correctly decoded.

In the LTE system, before the network device transmits a physical downlink control channel (hereinafter referred to as PDCCH), only some system information is transmitted. When the terminal receives the PDCCH transmitted by the base station, the terminal does not learn information such as number, size, positions of control channel elements (hereinafter referred to as CCE) occupied by the PDCCH and downlink control information (DCI) format transmitted by the PDCCH, and thus the terminal is required to perform blind detection on the PDCCH.

In the LTE system, the terminal blind detection refers to that the terminal finds a starting position of the CCE, and intercepts a guessed DCI length at the starting position of the CCE for decoding; if CRC of decoded information bits is the same as CRC carried in the PDCCH, determines that the information bits carried by the current PDCCH is downlink control information currently transmitted. Specifically, the terminal needs to determine which DCI format the PDCCH carries, and the terminal expects to obtain a certain DCI according to its current state. For example, when the terminal is in an idle state, the terminal expects to receive paging system information (hereinafter referred to as SI); when the terminal needs to transmit uplink data, the terminal expects to receive an uplink grant (hereinafter referred to as UL Grant); after the terminal initiates a random access procedure, the terminal expects to receive a random access channel response (hereinafter referred to as RACH Response) and so on. For different information, the terminal needs to use the corresponding Radio Network Temporary Identity (hereinafter referred to as RNTI) to perform Cyclic Redundancy Check (hereinafter referred to as CRC) with CCE information. If the check succeeds, the terminal learns that the information is required by itself, and then further parses content of corresponding DCI according to the modulation and coding manner.

If the terminal traverses all CCEs, it requires a lot of calculation. Therefore, available CCEs in the LTE system are divided into two search spaces, namely a common search space and a specific search space. Data transmitted in the common search space mainly includes system information (SI), Random Access Response (RAR), paging, and the like, and each terminal searches the common search space. The location of the common search space is fixed, on CCE0-CCE16, and the Aggregation Level (AL) for the common search space is only 4 and 8, so when the terminal searches the common search space, starting from CCE0, the terminal searches for 4 times as AL=4 and then searches for 2 times as AL=8. For the specific search space, search starting points of various terminals are different, and the AL of the search space is divided into four types, namely 1, 2, 4, and 8. Then, the terminal searches for 6 times as AL=1, searches for 6 times as AL=2, searches for 2 times as A=4, and searches for 2 times as AL=8. The number of blind detections performed by the terminal include searching for 6 times in the common search space and searching for 16 times in the specific search space. In the terminal-specific search space, the DCI format for the terminal at the same time has only two payload sizes, so the terminal needs to search twice, that is, 32 times.

In the NR system, due to the introduction of new DCI format, the DCI formats are more than that in the LTE system. The payload sizes of different DCI formats are quite different, and it is difficult to align payload sizes of different DCI formats to one or two types of payload sized by padding, which leads to high complexity of blind detection and an increase in the number of blind detections.

SUMMARY

In a first aspect, an embodiment of the present disclosure provides a downlink control information detecting method, applied to a terminal, and including:

obtaining indication information for indicating a candidate downlink control information (DCI) payload size;

according to the candidate DCI payload size indicated by the indication information, performing blind detection on a physical downlink control channel (PDCCH) and determining DCI transmitted in the PDCCH.

In a second aspect, an embodiment of the present disclosure provides a terminal including:

a first obtaining module used to obtain indication information for indicating candidate downlink control information (DCI) payload size;

a processing module used to perform blind detection on a physical downlink control channel (PDCCH) according to the candidate DCI payload size indicated by the indication information, and determine DCI transmitted on the PDCCH.

In a third aspect, an embodiment of the present disclosure provides a terminal including: a processor, a memory and a computer program stored on the memory and executable on the processor. The computer program is executed by the processor to implement steps of the above downlink control information detecting method.

In a fourth aspect, an embodiment of the present disclosure provides a computer readable storage medium including a computer program stored thereon. The computer program is executed by a processor to implement steps of the above downlink control information detecting method.

In a fifth aspect, an embodiment of the present disclosure provides a downlink control information transmitting method, applied to a network device, including:

transmitting indication information for indicating candidate downlink control information (DCI) payload size to a terminal;

transmitting a DCI corresponding to the indication information to the terminal by a physical downlink control channel (PDCCH).

In a sixth aspect, an embodiment of the present disclosure provides a network device including:

a first transmission module used to transmit indication information for indicating candidate downlink control information (DCI) payload size to a terminal;

a second transmission module used to transmit a DCI corresponding to the indication information to the terminal by a physical downlink control channel (PDCCH).

In a seventh aspect, an embodiment of the present disclosure provides a network device including: a processor, a memory and a computer program stored on the memory and executable on the processor. The computer program is executed by the processor to implement steps of the downlink control information transmitting method.

In an eight seventh aspect, an embodiment of the present disclosure provides a computer readable storage medium including a computer program stored thereon. The computer program is executed by a processor to implement steps of the downlink control information transmitting method.

