Systems and methods for packet payload mapping for robust transmission of data are described. For example, methods may include receiving, using a network interface, packets that each respectively include a primary frame and one or more preceding frames from the sequence of frames of data that are separated from the primary frame in the sequence of frames by a respective multiple of a stride parameter; storing the frames of the packets in a buffer with entries that each hold the primary frame and the one or more preceding frames of a packet; reading a first frame from the buffer as the primary frame from one of the entries; determining that a packet with a primary frame that is a next frame in the sequence has been lost; and, responsive to the determination, reading the next frame from the buffer as a preceding frame from one of the entries.

A timer for processing data blocks is proposed for a receiver of a mobile communications system. If the timer is not running, the timer is started based a data block. The data block has a sequence number higher than a sequence number of another data block that was first expected to be received. If the timer is stopped or expires, the timer is based on a highest sequence number of a data block among data blocks that cannot be delivered to a higher entity. The timer can be used to prevent a stall condition in mobile communications.

Techniques for sending packets and maintaining synchronization during handover is described. A user equipment (UE) may be handed over from a source base station to a target base station. The source base station may forward packets for the UE to the target base station, which may receive the packets out of order. In one design, the target base station may determine whether each packet can be sent in order to the UE, send the packet if it can be sent in order, and discard the packet otherwise. In another design, the target base station may re-order packets received within a re-ordering window and may send the re-ordered packets to the UE. In yet another design, the target base station may process each packet received out of order as if the packet is in order, e.g., by incrementing a hyper-frame number (HFN) or re-assigning the packet with a later sequence number.

The present invention provides a network-based real-time video transmission method, comprising: 1) caching, by a transmitting terminal, an already transmitted original data packet, and recording the transmission moment of the original data packet; 2) counting, by a receiving terminal, lost data packets and current real-time network condition information and feeding back these information to the transmitting terminal; 3) constructing, by the transmitting terminal, a retransmission data packet according to the cached lost data packet using a variable-code forward error correction technology, and transmitting the retransmission data packet to the receiving terminal, wherein the error correction rate of the retransmission data packet is determined according to the remaining lifetime of the lost data packet and the real-time network condition information; and, 4) receiving, by the receiving terminal, the retransmission data packet and recovering the lost data packet.

Systems and methods for packet payload mapping for robust transmission of data are described. For example, methods may include receiving, using a network interface, packets that each respectively include a primary frame and one or more preceding frames from the sequence of frames of data that are separated from the primary frame in the sequence of frames by a respective multiple of a stride parameter; storing the frames of the packets in a buffer with entries that each hold the primary frame and the one or more preceding frames of a packet; reading a first frame from the buffer as the primary frame from one of the entries; determining that a packet with a primary frame that is a next frame in the sequence has been lost; and, responsive to the determination, reading the next frame from the buffer as a preceding frame from one of the entries.

Systems and methods for packet payload mapping for robust transmission of data are described. For example, methods may include receiving, using a network interface, packets that each respectively include a primary frame and one or more preceding frames from the sequence of frames of data that are separated from the primary frame in the sequence of frames by a respective multiple of a stride parameter; storing the frames of the packets in a buffer with entries that each hold the primary frame and the one or more preceding frames of a packet; reading a first frame from the buffer as the primary frame from one of the entries; determining that a packet with a primary frame that is a next frame in the sequence has been lost; and, responsive to the determination, reading the next frame from the buffer as a preceding frame from one of the entries.

The disclosure relates to a pre-5.sup.th-Generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4.sup.th-generation (4G) communication system such as long term evolution (LTE). A method of operating a user equipment (UE) and an apparatus therefor are provided. The method includes detecting an occurrence of a first state related to a state of a buffer for a packet data convergence protocol (PDCP) entity, transmitting a request message indicating the occurrence of the first state to a base station (BS), and receiving one or more packets from the BS based on transmission control performed based on the request message.

Methods, systems, and devices for wireless communications are described. A receiving device may receive, at a first operational layer of the receiving device, one or more protocol data units (PDUs) within a set of PDUs. The receiving device may identify, at a second operational layer of the receiving device, a sequence gap associated with a missing PDU from the set of PDUs, the first operational layer being a lower operational layer of the receiving device than the second operational layer. The receiving device may determine, at the second operational layer, that a triggering condition associated with the missing PDU has occurred. The receiving device may provide, by the second operational layer and based at least in part on the triggering condition occurring, an indication to update a reception buffer of the first operational layer to a last received protocol data unit of the set of PDUs.

An electronic device that communicates frames is described. During operation, the electronic device may transmit the frames addressed to a recipient electronic device and associated with multiple links between the electronic device and the recipient electronic device. Then, the electronic device may receive block acknowledgments for at least a subset of the frames, where a given block acknowledgment is associated with the recipient electronic device and indicates received frames on a given link in the links. Moreover, the electronic device may control an amount of traffic conveyed on the links based at least in part on the block acknowledgments. Next, the electronic device may store a remainder of the frames based at least in part on the block acknowledgments, where the frames include the subset of the frames and the remainder of the frames. Note that the frames may have a common traffic identifier.

A receiving method, a sending method and communications device are provided. The receiving method includes: obtaining a duplication detection parameter; and performing duplication detection on a received sidelink packet data convergence protocol PDCP protocol data unit PDU by using the duplication detection parameter.