The present invention relates to a technology for a sensor network, machine to machine (M2M) communication, machine type communication (MTC), and the Internet of things (IoT). The present invention can be used for intelligent services (smart home, smart building, smart city, smart car or connected car, health care, digital education, retailing, security and safety related services, and the like) based on the technology. The present invention provides a method by which a node transmits a signal in a mesh network, the method comprising the steps of: transmitting a packet; receiving at least one packet transmitted from at least one peripheral node except for the node, after transmitting the packet; determining whether the at least one peripheral node has normally received the packet on the basis of the at least one packet; and retransmitting the packet if it is determined that it is necessary to retransmit the packet, on the basis of the determination result.

The present invention relates to a technology for a sensor network, machine to machine (M2M) communication, machine type communication (MTC), and the Internet of things (IoT). The present invention can be used for intelligent services (smart home, smart building, smart city, smart car or connected car, health care, digital education, retailing, security and safety related services, and the like) based on the technology. The present invention provides a method by which a node transmits a signal in a mesh network, the method comprising the steps of: transmitting a packet; receiving at least one packet transmitted from at least one peripheral node except for the node, after transmitting the packet; determining whether the at least one peripheral node has normally received the packet on the basis of the at least one packet; and retransmitting the packet if it is determined that it is necessary to retransmit the packet, on the basis of the determination result.

Aspects of the present disclosure provide various hybrid automatic repeat request (HARQ) retransmission indication schemes used in a HARQ retransmission process. The HARQ retransmission indication can implicitly or explicitly indicate which part of a transport block (TB), code block group(s), or code block(s) is/are being retransmitted so that the receiver can associate the retransmitted TB, code block group(s), code block(s) with the correct prior reception, for example, for HARQ combining purposes.

Aspects of the present disclosure provide various hybrid automatic repeat request (HARQ) retransmission indication schemes used in a HARQ retransmission process. The HARQ retransmission indication can implicitly or explicitly indicate which part of a transport block (TB), code block group(s), or code block(s) is/are being retransmitted so that the receiver can associate the retransmitted TB, code block group(s), code block(s) with the correct prior reception, for example, for HARQ combining purposes.

In an embodiment, a UE determines QCL information that indicates an association between a spatial parameter and a current transmission configuration, and conveys the determined QCL information to a BS. In another embodiment, a BS transmits a DCI that triggers transmission of a reference signal that includes QCL information that indicates an association between a spatial parameter and a current transmission configuration, whereby any DCI triggering any reference signal that includes any QCL information is configured to trigger a UE to send an express acknowledgment or an implied acknowledgment to that DCI.

A method is provided in a receiving node for handling status information of data units transmitted from a sending node to the receiving node over a radio link. The receiving node establishes that a number of data units that has been transmitted by the sending node are missing. The receiving node sends a reduced status message to the sending node over the radio link, which message is reduced such that it comprises the negative acknowledgement for a first part of missing data units and omits negative acknowledgements for the rest of the missing data units. The omitted negative acknowledgement for the rest of the missing data units will not erroneously be interpreted as correctly received data units by the sending node.

A method is provided in a receiving node for handling status information of data units transmitted from a sending node to the receiving node over a radio link. The receiving node establishes that a number of data units that has been transmitted by the sending node are missing. The receiving node sends a reduced status message to the sending node over the radio link, which message is reduced such that it comprises the negative acknowledgement for a first part of missing data units and omits negative acknowledgements for the rest of the missing data units. The omitted negative acknowledgement for the rest of the missing data units will not erroneously be interpreted as correctly received data units by the sending node.

A terminal apparatus for performing radio communication with another terminal apparatus via a base station apparatus, the terminal apparatus including: a transmitter configured to transmit, to the base station apparatus, a signal of data addressed to the other terminal apparatus; a receiver configured to receive a signal from the base station apparatus to the other terminal apparatus; and a controller configured to determine whether the base station apparatus has successfully received the signal of the data transmitted from the transmitter to the other terminal apparatus, by using the signal from the base station apparatus to the other terminal apparatus received by the receiver.

A terminal apparatus for performing radio communication with another terminal apparatus via a base station apparatus, the terminal apparatus including: a transmitter configured to transmit, to the base station apparatus, a signal of data addressed to the other terminal apparatus; a receiver configured to receive a signal from the base station apparatus to the other terminal apparatus; and a controller configured to determine whether the base station apparatus has successfully received the signal of the data transmitted from the transmitter to the other terminal apparatus, by using the signal from the base station apparatus to the other terminal apparatus received by the receiver.

An embodiment of the invention relates to a method of operating a communication system (10) that comprises at least four communication nodes (A, B, C, D). The communication system is operated in a time-division multiplexing technique wherein the communication is carried out in consecutive time frames which are divided into slots. At least one slot is allocated to each of the communication nodes. Each of the slots comprises, or preferably consists of, at least two consecutive sub-slots, hereinafter referred to as transmission sub-slot (TSS1-TSS4) and echo sub-slot (ESS1-ESS4). Echo signals (E (DS1)-E (DS4)) are transmitted during echo sub-slots (ESS1-ESS4).