CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 U.S. National Stage of International Application No. PCT/CN2018/078232, filed on Mar. 7, 2018, which claims priority to Chinese Application No. 201710308732.0, filed on May 4, 2017. The entire disclosures of the above applications are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a field of communication, and in particular to a Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback method at a base station side, a HARQ-ACK extraction method at a user equipment side, a base station, and a user equipment.

BACKGROUND

With development of the mobile communication industry and ever-growing demand for mobile data services, requirements on speed and Quality of Service (QoS) of mobile communications are getting higher. Currently, standards for the network diversified, wideband, integrated and intelligent 5th generation (5G) mobile communication technology are being developed and applied. In an application scenario of an Internet of Things, it is expected to implement massive connections between people and objects, as well as between objects, to improve network coverage rate and resource efficiency and save power consumption of a user equipment. In Rel-13, it is proposed to apply uplink data retransmission to improve network coverage rate. For example, a set of numbers of times of uplink data retransmission may be defined as: {1, 4, 8, 16, 32 . . . 2048}. With respect to the maximum number of times of retransmissions 16 as indicated by Radio Resource Control (RRC), the number of times of retransmissions for a specific user equipment (UE) may be set to {1, 4, 8, 16}. Since a granularity gap of uplink transmission is too large and measurement is inaccurate, uplink data in the IoT application scenario should support early acknowledgement from a base station, that is, the base station needs to transmit a HARQ-ACK to the user.

When the HARQ-ACK fed back to the user equipment by the base station is ACK, it indicates that the base station has correctly received and decoded data transmitted by the user equipment. That is, the user equipment no longer needs to transmit the data to the base station.

In order to implement early acknowledgement for reception of uplink data in the IoT application scenario, a group-based HARQ-ACK feedback mechanism has been proposed. Specifically, the base station may indicate HARQ-ACK information for a plurality of user equipments in Downlink Control Information (DCI). With respect to the DCI for HARQ-ACK feedback, the base station may scramble, by employing a Hybrid Automatic Repeat reQuest Radio Network Temporary Identifier (HARQ-RNTI), a Cyclic Redundancy Check (CRC) calculated based on the HARQ-ACK information for the plurality of user equipments. Accordingly, the user equipment checks the received DCI according to the HARQ-RNTI, so as to identify whether the received DCI is the DCI for HARQ-ACK feedback, and further determine a HARQ-ACK value belonging to itself.

In this case, the DCI for HARQ-ACK feedback carries HARQ-ACKs for each user equipment (shown inFIG. 1). In order that each user equipment can identify HARQ-ACK information belonging to the user equipment, the base station notifies, through Radio Resource Control (RRC) signaling, each user equipment of a bit position of HARQ-ACK information corresponding thereto. However, a problem with this method is that overhead of DownLink (DL) signaling is enormous in a scenario of massive connections with many user equipments.

SUMMARY

In view of the above circumstances, it is expected to provide a HARQ-ACK feedback method, a HARQ-ACK extraction method, a base station, and a user equipment that can effectively reduce downlink signaling overhead.

According to a first aspect of the present invention, there is provided a Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback method performed by a base station, and used to feed back corresponding HARQ-ACKs to a plurality of user equipments, the method comprising: generating, by employing a plurality of HARQ-ACKs corresponding to the plurality of user equipments, at least one piece of downlink control information, wherein for each user equipment, an implicit mapping relationship exists between the user equipment and one or more information bits of the downlink control information; and transmitting to the plurality of user equipments the downlink control information.

According to a second aspect of the present invention, there is provided a Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) extraction method performed by a user equipment, comprising: receiving at least one piece of downlink control information for feeding back corresponding HARQ-ACKs to a plurality of user equipments transmitted by a base station, wherein the plurality of user equipments include the user equipment and other user equipments; and determining a HARQ-ACK corresponding to the user equipment, based on an implicit mapping relationship between the user equipment and one or more information bits of the downlink control information.

According to a third aspect of the present invention, there is provided a base station, configured to perform Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback to a plurality of user equipments, comprising: a generating unit, configured to generate, by employing a plurality of HARQ-ACKs corresponding to the plurality of user equipments, at least one piece of downlink control information, wherein for each user equipment, an implicit mapping relationship exists between the user equipment and one or more information bits of the downlink control information; and a transmitting unit, configured to transmit to the plurality of user equipments the downlink control information.

According to a fourth aspect of the present invention, there is provided a user equipment, configured to perform extraction of Hybrid Automatic Repeat reQuest ACKnowledgements (HARQ-ACKs) from a base station, comprising: a receiving unit, configured to receive at least one piece of downlink control information for feeding back corresponding HARQ-ACKs to a plurality of user equipments transmitted by a base station, wherein the plurality of user equipments include the user equipment and other user equipments; and a determining unit, configured to determine a HARQ-ACK corresponding to the user equipment, based on an implicit mapping relationship between the user equipment and one or more information bits of the downlink control information.

By employing the HARQ-ACK feedback method, the HARQ-ACK extraction method, the base station, and the user equipment according to the present invention, an implicit mapping relationship is established between the plurality of user equipments and information bits of the downlink control information, so that each of the user equipments can autonomously determine corresponding HARQ-ACK in the downlink control information, without DL signaling to notify the user equipments one by one of the information bits of the HARQ-ACKs corresponding to the respective user equipments in the downlink control information. Therefore, DL signaling overhead is significantly reduced as compared with the prior art.

