Network Coding Retransmission Design with Common Feedback Channel IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-09/0437 Date Submitted: 2009-02-27 Source: Hung-Yu Wei, Ching-Chun Chou Voice: [Telephone Number (optional)] Department of Electrical Engineering, E-mail: hywei@cc.ee.ntu.edu.tw National Taiwan University f95921098@ntu.edu.tw Venue: In response to Call for SDD comments Base Contribution: Purpose: To be discussed and adopted by TGm for use in the IEEE 802.16m Notice: This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.16. Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: <http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>. Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.

Basic Idea Observation Basic idea Given an MBS group and a set of packets for transmission Transmission error could occur on any packets/nodes If there is only 1 or no packet loss, 1 XOR-coded retransmission could recover the transmission error. This holds for every MSj in the MBS group Basic idea 1 XOR-coded retransmission packet for an MBS group with only 1 or no packet loss. Feedback design Use E-MBS common feedback channel to transmit NACK NACK feedback when 2 packet loss occurs

E-MBS with Common Feedback Channel Network-Coding based retransmission Common feedback channel to transmit NACK X: Erroneous reception The XOR-coded retransmission packet could repair packet losses from P1 to P5. P1+P2+P3+P4+P5 Next batch starts from P6. P1 P2 P3 P4 P5 P6 x BS MS1 MS2 MS3 Uplink feedback More than 1 packet loss for MS1 & MS3

NACK Common Feedback and XOR retransmission BS transmits MBS packets P1, P2, … If there is exactly 1 packet loss among previous transmitted packet P1~P(k-1) for MSj . When packet Pk is lost, MSj sends NACK through common feedback channel After receiving NACK, BS retransmits network coded packet R=(P1…  P(k-1)) The next batch starts BS transmits Pk, P(k+1), ….

Proposed Text 14.3.3 E-MBS Operation with Retransmission Details on E-MBS Operation with HARQ retransmission is FFS. An ABS may use a network-coding based retransmission scheme that does not require a feedback channel. Modify the text marked in red as An ABS may use a network-coding based retransmission scheme with or without E-MBS common feedback channel.