TECHNICAL FIELD

The disclosure relates to the field of wireless communications technologies, and in particular, to an uplink transmission method, a terminal, and a network side device.

BACKGROUND

In a wireless cellular network system such as a Long Term Evolution (LTE) system, before sending uplink data, a terminal needs to first establish a radio resource control (RRC) connection to a base station to enter a radio resource control connected mode, and then send a scheduling request (SR) to the base station. If the base station allows the terminal to send the uplink data, the base station sends a grant instruction to the terminal. The terminal can send the uplink data to the base station based on a requirement of the instruction only after receiving the grant instruction. Such an uplink data sending method is referred to as grant-based transmission.

Grant-based transmission has two disadvantages. One disadvantage is that a latency is relatively large. The latency herein is a latency from a moment at which the terminal determines that uplink data needs to be sent to a moment at which the terminal sends the data through an air interface. The other disadvantage is that when a very large quantity of terminals need to send uplink data in a specific period of time, a very large quantity of uplink and downlink control channel resources are consumed for sending a scheduling request and grant, thereby resulting in a relatively high proportion of control overheads to total network overheads (for example, power and air interface resources). This disadvantage of the grant-based transmission is particularly evident when all services of the terminal are small data packet services.

A basic idea of grant-free (GF) transmission is that data is received and sent without a grant. To be specific, when the terminal determines that uplink data needs to be sent, the terminal directly processes the data and then sends the processed data to the base station without a need to send an uplink scheduling request and wait to receive a grant from the base station. In comparison with a grant-based transmission solution in which a base station needs to perform scheduling, in the grant-free transmission, there is no need to send an uplink scheduling request and wait to receive a grant from the base station, so that a transmission latency can be shortened and a latency requirement can be met.

For use of GF transmission, using retransmission to improve transmission reliability needs to be considered.

A possible retransmission manner is based on an ACK/NACK feedback: After sending data information to the base station on a GF time-frequency resource, the terminal waits for a feedback from the base station on the data packet. If the terminal receives a NACK feedback or receives no ACK feedback, and the data packet does not expire, the terminal retransmits the data information, to increase a possibility of correctly receiving the data packet by the base station.

Another possible retransmission manner is not based on an ACK/NACK feedback: After sending data information to the base station on a GF time-frequency resource, the terminal retransmits the data packet on a next available GF time-frequency resource until an ACK from the base station is received or the data packet expires.

However, the inventor finds that for GF transmission, retransmitted data cannot be correctly received and processed by the base station. Consequently, reliability of grant-free transmission cannot be ensured.

SUMMARY

The disclosure describes an uplink transmission method, a terminal, and a network side device.

According to one aspect, an embodiment of the disclosure provides an uplink transmission method, including: pre-allocating, by a network side device, an uplink transmission time-frequency resource to a terminal, and storing, by the terminal, the uplink transmission resource allocated by the network side device to the terminal; and when the terminal needs to send a data packet, sending, by the terminal, the data packet to the network side device by using the uplink transmission resource, where the data packet includes indication information, the indication information is used to indicate whether the data packet is initially transmitted by the terminal or the data packet is retransmitted by the terminal, and the network side device can correctly receive and perform combining processing on the data packet based on the indication information, to improve reliability of uplink grant-free transmission.

Herein, that the terminal stores the uplink transmission time-frequency resource pre-allocated by the network side device to the terminal usually means that the network side device pre-allocates and notifies a plurality of transmission resources to the terminal device, so that when the terminal needs to send a data packet, the terminal directly uses the transmission resource without a need to request allocation from the network side device each time, to reduce a latency. A specific implementation scenario is, for example, grant-free transmission or semi-persistent scheduling.

The indication information herein is sent to the network side device by using control information, or is implicitly indicated by using a reference signal. The indication information includes several types of parameters. One type of parameter indicates whether currently transmitted data information is initially transmitted or retransmitted; another type of parameter indicates whether currently transmitted data information is synchronously retransmitted or asynchronously retransmitted; still another type of parameter indicates whether current retransmission is adaptive retransmission or non-adaptive retransmission; and yet another type of parameter indicates whether next time of retransmission of the terminal is grant-based transmission or grant-free transmission.

In a possible implementation, a quantity of slots of an interval between the initially transmitted data packet and the retransmitted data packet is any value. During such adaptive retransmission, a manner of indicating initially transmitted and retransmitted information by using indication information in the disclosure is also applicable.

In a possible implementation, the indication information includes one or more of the following parameters: a hybrid automatic repeat request (HARQ) process identity (ID), a new data indicator (NDI), a resource block assignment (RBA) indicator, a redundancy version (RV), and a buffer status report (BSR).

In the implementation that the indication information is carried in the control information, different values assigned to each parameter represent different transmission statuses.

Different values used for the HARQ process ID represent different HARQ processes. For example, a value 0 assigned to the HARQ process ID represents that the terminal transmits data in a process HARQ 0; and a value 1 assigned to the HARQ process ID represents that the terminal transmits data in a process HARQ 1.

Alternatively, different values used for the NDI represent an initially transmitted data packet or a retransmitted data packet. For example, a value 0 assigned to the NDI represents an initially transmitted data packet, and a value 1 assigned to the NDI represents a retransmitted data packet; or a value 1 assigned to the NDI represents an initially transmitted data packet, and a value 0 assigned to the NDI represents a retransmitted data packet. Alternatively, when a value of the NDI is not toggled or is the same as a previous value, the value of the NDI represents an initially transmitted data packet; or when a value of the NDI is toggled or is not the same as a previous value, the value of the NDI represents a retransmitted data packet.

Alternatively, different values used for the redundancy version (RV) represent a quantity of retransmission times and an initially transmitted data packet or a retransmitted data packet. For example, a value 0 assigned to the RV represents an initially transmitted data packet, a value 1 assigned to the RV represents a data packet retransmitted for a first time, and a value 2 assigned to the RV represents a data packet retransmitted for a second time. Alternatively, when a value of the RV is not toggled or is the same as a previous value, the value of the RV represents an initially transmitted data packet, or when a value of the RV is toggled or is not the same as a previous value, the value of the RV represents a retransmitted data packet.

Alternatively, different values used for the RBA represent different time-frequency resources used by initially transmitted data and retransmitted data. For example, a value 0 assigned to the RBA represents an initially transmitted data packet, and a value 1 assigned to the RBA represents a retransmitted data packet; or a value 1 assigned to the RBA represents an initially transmitted data packet, and a value 2 assigned to the RBA represents a retransmitted data packet.

Alternatively, different values used for the buffer status report (BSR) represent that a data packet to be sent next time by the terminal is transmitted by using the stored uplink transmission resource, namely, grant-free transmission, or that a data packet to be sent next time by the terminal is transmitted by using an uplink transmission resource allocated by the network side device as re-requested, namely, grant-based transmission. For example, a value 0 assigned to the BSR represents that the data packet to be sent next time is transmitted by using the stored uplink transmission resource, namely, grant-free transmission, and a value 1 assigned to the BSR represents that the data packet to be sent next time is transmitted by using the uplink transmission resource allocated by the network side device as re-requested, namely, grant-based transmission; or a value 1 assigned to the BSR represents that the data packet to be sent next time is transmitted by using the stored uplink transmission resource, namely, grant-free transmission, and a value 0 assigned to the BSR represents that the data packet to be sent next time is transmitted by using the uplink transmission resource allocated by the network side device as re-requested, namely, grant-based transmission. Alternatively, when a value of the BSR is not toggled or is the same as a previous value, the value of the BSR represents that the data packet to be sent next time is transmitted by using the stored uplink transmission resource, namely, grant-free transmission; or when a value of the BSR is toggled or is not the same as a previous value, the value of the BSR represents that the data packet to be sent next time is transmitted by using the uplink transmission resource allocated by the network side device as re-requested, namely, grant-based transmission.

According to the uplink transmission method provided in the disclosure, when the terminal sends the data packet to the network side device, the terminal notifies, by using the indication information, the network side device that the currently transmitted data packet is a retransmitted data packet or an initially transmitted data packet, so that the network side device can correctly receive and effectively combine the initially transmitted data packet and the retransmitted data packet, to improve reliability of grant-free transmission.

According to another aspect, an embodiment of the disclosure provides a terminal. The terminal has a function of implementing behavior of the terminal in the foregoing method design. The function of the terminal may be implemented by hardware including a transceiver and a processor, or may be implemented by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the foregoing function. The module may be software and/or hardware.

According to still another aspect, the disclosure provides a terminal, including:

a memory, configured to store an uplink transmission resource allocated by a network side device to the terminal; and

a transceiver, configured to: when the terminal needs to send a data packet, send the data packet to the network side device by using the uplink transmission resource stored in the memory, where the data packet includes indication information, and the indication information is used to indicate whether the data packet is initially transmitted by the terminal or the data packet is retransmitted by the terminal.

According to yet another aspect, the disclosure provides a network side device, including:

a transceiver, configured to receive a data packet sent by a terminal to the network side device by using a pre-allocated uplink transmission resource, where the data packet includes indication information, and the indication information is used to indicate whether the data packet is initially transmitted by the terminal or the data packet is retransmitted by the terminal; and

a processor, configured to perform combining processing on the data packet based on the indication information.

According to still yet another aspect, an embodiment of the disclosure provides a base station. The base station has a function of implementing behavior of the base station in the foregoing method design. The function may be implemented by hardware, or may be implemented by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the foregoing function.

In a possible design, a structure of the base station includes a processor and a transceiver. The processor is configured to support the base station in performing corresponding functions in the foregoing method. The transceiver is configured to support communication between the base station and a terminal, send information or signaling in the foregoing method to the terminal, and receive information or an instruction sent by the base station. The base station may further include a memory, and the memory is configured to: be coupled to the processor, and store a program instruction and data that are necessary for the base station.

According to a further aspect, an embodiment of the disclosure provides a control node. The control node may include a controller/processor, a memory, and a communications unit. The controller/processor may be configured to coordinate resource management and configuration between a plurality of base stations, and may be configured to perform the method of combining data information in the foregoing embodiment. The memory may be configured to store program code and data of the control node. The communications unit is configured to support the control node in communicating with a base station, for example, sending information about a configured resource to the base station.

According to a still further aspect, an embodiment of the disclosure provides a communications system. The system includes the base station and the terminal in the foregoing aspects. In an implementation, the system may further include the control node in the foregoing embodiment.

According to a yet further aspect, an embodiment of the disclosure provides a computer storage medium. The computer storage medium is configured to store a computer software instruction used by the foregoing base station, and the computer software instruction includes a program designed to perform the foregoing aspects.

According to a still yet further aspect, an embodiment of the disclosure provides a computer storage medium. The computer storage medium is configured to store a computer software instruction used by the foregoing terminal, and the computer software instruction includes a program designed to perform the foregoing aspects.

According to the terminal and the network side device provided in the disclosure, when the terminal sends the data packet to the network side device, the terminal notifies, by using the indication information, the network side device that the currently transmitted data packet is a retransmitted data packet or an initially transmitted data packet, so that the network side device can correctly receive and effectively combine the initially transmitted data packet and the retransmitted data packet, to improve reliability of grant-free transmission.

