Base station and a plurality of member nodes for transmitting and receiving network coding based multicast traffic

Patent metadata

Field	Value
Publication number	US-9961509-B2
Application number	US-201314079934-A
Country	US
Kind code	B2
Filing date	Nov 14, 2013
Priority date	Nov 14, 2012
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

Provided are a base station and a plurality of member nodes for transmitting and receiving network coding based multicast traffic. The base station may transmit multicast traffic, and the member node may transmit an acknowledgement (ACK) signal based on received multicast traffic. A determination made be made as to whether the multicast traffic is to be retransmitted, based on a number of member nodes transmitting ACK signals.

First claim

What is claimed is:

1. An apparatus for transmitting a multicast packet, the apparatus comprising: a processor configured to:
control a transceiver of the apparatus to transmit a first multicast packet to a plurality of member nodes belonging to a multicast group, the first multicast packet comprising a plurality of network coded packets generated by network coding a plurality of data packets;
control the transceiver to receive at least one ACK signal transmitted from at least one of the plurality of member nodes;
determine whether to retransmit at least one of the plurality of network coded packets using a second multicast packet based on the at least one ACK signal;
determine a number of network coded packets to be included in the second multicast packet based on a number of the at least one ACK signal and a number of previous retransmissions for the plurality of network coded packets in response to determining that at least one of the plurality of network coded packets are to be retransmitted;
determine a subset of the plurality of network coded packets to be included in the second multicast packet for retransmission;
generate the second multicast packet comprising the subset of the plurality of network coded packets; and
control the transceiver to transmit the second multicast packet to the plurality of member nodes, wherein the processor is further configured to determine whether the second multicast packet is to be transmitted based on the at least one ACK signal and an operating mode corresponding to a type of the at least one ACK signal.

2. The apparatus of claim 1 , further comprising:
a memory configured to store a codebook shared with the plurality of member nodes, wherein the processor is further configured to:
network code the plurality of data packets using a plurality of code words included in the codebook to generate the plurality of network coded packets; and
generate the first multicast packet comprising the plurality of network coded packets and a codebook index corresponding to the plurality of code words.

3. The apparatus of claim 1 , wherein the processor is further configured to:
count the number of the at least one ACK signal; and
compare the number of the at least one ACK signal with a number of the plurality of member nodes in response to a type of the at least one ACK signal corresponding to a complete ACK type, and decide the second multicast packet is to be transmitted in response to a result of the comparing, wherein the result of the comparing shows the number of the at least one ACK signal being less than the number of the plurality of member nodes.

4. The apparatus of claim 1 , wherein the processor is further configured to:
count the number of the at least one ACK signal; and
decide the second multicast packet is to be transmitted in response to at least one of the number of the at least one ACK signal being a type of ACK signal that corresponds to a complete negative acknowledgement (NACK) type.

5. The apparatus of claim 1 , wherein the processor is further configured to: determine whether the at least one ACK signal is present; and
decide the second multicast packet is to be transmitted in response to a determination that the at least one ACK signal is present and a type of the at least one ACK signal corresponds to a complete NACK type.

6. The apparatus of claim 1 , wherein the processor is further configured to:
count the number of the previous retransmissions for the plurality of network coded packets; and
decide that none of the plurality of network coded packets is to be retransmitted, when the number of the previous retransmissions reaches a predetermined maximum number of retransmissions.

7. The apparatus of claim 1 , wherein the processor is configured to be in a receptive state for the at least one ACK signal for a predetermined time period after the first multicast packet is transmitted, and
wherein the predetermined time period is known by the apparatus and the plurality of member nodes.

8. A member node for receiving multicast traffic from an apparatus, the member node comprising:
a processor configured to:
control a transceiver of the member node to receive a multicast packet from the apparatus;
determine whether the multicast packet is successfully received; and
control the transceiver to transmit an ACK signal to the apparatus, based on a result of the determining and an operating mode corresponding to a type of the ACK signal,
wherein the processor is further configured to:
overhear ACK signals transmitted to the apparatus from a plurality of member nodes included in a multicast group, when a type of the ACK signals corresponds to a complete negative acknowledgement (NACK) type; and
generate an ACK signal of the complete NACK type, in response to a determination that an overheard ACK signal is absent and a determination that the multicast packet is not successfully received.

9. The member node of claim 8 , wherein the processor is further configured to generate the ACK signal of a complete ACK type, in response to a determination that the multicast packet is successfully received, when a type of the ACK signal corresponds to the complete ACK type.

10. The member node of claim 8 , wherein the processor is further configured to receive a packet retransmitted from the apparatus,
wherein the multicast packet comprises a plurality of network coded packets generated by network coding a plurality of data packets, and
wherein the processor is further configured to determine whether the plurality of data packets are successfully received, based on the retransmitted packet and network coded packets being successfully received from among those originally included in the multicast packet comprising the plurality of network coded packets.

11. The member node of claim 8 , further comprising:
a memory configured to store a codebook shared with the apparatus and a plurality of member nodes included in the multicast group,
wherein the processor is further configured to:
extract a codebook index from the multicast packet; and
decode a plurality of network coded packets included in the multicast packet, using code words corresponding to the extracted codebook index, among a plurality of code words included in the codebook.

12. A method for transmitting a multicast packet, comprising:
transmitting a first multicast packet to a plurality of member nodes belonging to a multicast group, the first multicast packet comprising a plurality of network coded packets generated by network coding a plurality of data packets;
receiving at least one ACK signal transmitted from at least one of the plurality of member nodes;
determining whether to retransmit at least one the plurality of network coded packets using a second multicast packet based on the at least one ACK signal;
determining a number of network coded packets to be included in the second multicast packet based on a number of the at least one ACK signal and a number of previous retransmissions for the plurality of network coded packets in response to determining that at least one of the plurality of network coded packets are to be retransmitted;
determining a subset of the plurality of network coded packets to be included in the second multicast packet for retransmission;
generating the second multicast packet comprising the subset of the plurality of network coded packets; and
transmitting the second multicast packet to the plurality of member nodes,
wherein the determining whether to retransmit at least one of the plurality of network coded packets comprises determining whether the second multicast packet is to be transmitted based on the at l

Assignees

• Samsung Electronics Co Ltd

Inventors

• Shin Won Jae
• Lim Jong Bu
• Jang Kyung Hun

Classifications

• H04W4/06 Primary

  Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services · CPC title

• H04L1/188

  Time-out mechanisms · CPC title

• H04L1/1692

  Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts · CPC title

• H04L2001/0093

  Point-to-multipoint · CPC title

• H04L1/0076

  Distributed coding, e.g. network coding, involving channel coding (coding in both space and time H04L1/0618; cooperative diversity H04B7/022) · CPC title