Uplink HARQ Feedback Channel Design for IEEE802.16m Document Number: IEEE C802.16m-08/968 Date Submitted: 2008-09-05 Source: Dengkui Zhu E-mail: zhu.dengkui@zte.com,cn Yanfeng Guan Ying Liu zhaohua Lu Xiangyu Liu ZTE Corporation Venue PHY: Text; in response to the TGm Call for Contributions and Comments 802.16m-08/033 for Session 57 Base Contribution Purpose To be discussed and adopted by TGm for use in the IEEE 802.16m SDD 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/sect 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 >.

Overview ACK Channel resource structure ACK channel design Simulation results Proposal Text

ACK Channel Structure(1) The SDD Text of IEEE C80216m-08/003r4 has described ACK Channel is FDM with data and other control channel. We suggest the basic resource unit in UL HARQ feedback channel should be consistent with data and other control channel for the convenient of resource permutation and mapping,so the structure of 18*6(Freq*Time) of LRU is also for the ACK channel. In the ACK channel, Distributed LRU(DLRU) should be employed for the reason that frequency diversity gain would be captured . As in figure 1,all the UL HARQ feedback channel in one UL subframe make up of UL HARQ feedback region in which DLRU is the resource unit. Figure1 UL HARQ feedback region

ACK Channel Structure(2) When the DLRU contains 2 tiles, the structure of tile is 6 by 6 as in figure2. Tile 2 &3 is the repeat of tile1 in order to capture the freq diversity gain. Figure2: the structure of DLRU in HARQ feedback region

ACK Channel Design(1) Each tile of a DLRU is composed of a data zone which contain all the subcarrier of symbol 1,3,4,6,and a pilot zone which contain all the subcarrier of symbol 2,4 as in figure . CDM is used to multiplexing ACK channels in each DLRU, where is the freq spreading nums and is the time spreading nums. Each ACK channel transmits one ACK/NAK message. Each ACK channel corresponds to a freq domain spreading sequence and a time domain spreading sequence Figure3 Tile structure in HARQ feedback resource unit

ACK Channel Design(2) Each ACK channel corresponds a freq domain pilot sequence and a time domain pilots spreading sequence . is chosen from orthogonal sequence set , and is chose from orthogonal sequence set , is chosen from orthogonal sequence set , and is chosen from orthogonal sequence set . Each feedback message is modulated with BPSK/QPSK signal . when BPSK is used, each HARQ feedback channel transmits one ACK/NAK messages. when QPSK is used, each HARQ feedback channel transmits two ACK/NAK messages as MCW is used in MIMO.

ACK Channel Design(3) -data spread sequence select() The sequence in is chosen from the column of DFT matrix or ZC sequence. E.g. is chosen from as follows: is generate as follows: is chosen from as follows (1) (2) (3) (4)

ACK Channel Design(4) -pilot sequence select is chosen from the ZC sequence, and they must satisfy the condition that any one of the sequence of is circular of the other one. E.g. is chosen from as follows: is generate as follows: (5) (6) (7) (8)

Simulation parameter Parameter value Carrier Frequency 2.5GHz Antenna configuration 1Tx,2Rx Channel Model ITU(PB,VA),TU Mobile speed 3km/h,120km/h UL symbol 18(one frame) HARQ feedback transmission unit num 30(one frame) 6*2 Detect method Semi-Coherent Pilot boosting 2.5dB ACK/NACK format BPSK/QPSK

Simulation results From the simulation results, the SNR for per =1% is about -10dB for ITU PB3km/h channel, and about -7dB for ITU PB120km/h.

Proposal text 11.9.2.2UL HARQ Feedback Control Channel Text proposed for IEEE C802.16m-08/003r4 -------------start of proposed SDD text ---------------- 11.9.2.2UL HARQ Feedback Control Channel 11.9.2.2.2 PHY Structure All the UL HARQ feedback channel In the UL subframe make up of a HARQ feedback region in which, Distributed LRU (DLRU) is the basic resource allocation unit. The structure DLRU is 6 continue OFDM in time by 18 sub-carriers in frequency. The DLRU is composed of two non-adjacent tiles(tile1 and tile2). Tile2 is the repeat of tile1 so as to capture frequency diversity gain. The structure of the tile is 6 continue OFDM symbol by 6 adjacent subcarrier in frequency. A HARQ feedback channel transmission unit is compose of two tiles from the same DLRU. Each tile in the HARQ feedback channel transmission unit is divided into two parts as in figure4, one is for effective data transmission which contain all the subcarrier of the 1,3,4,6th symbols while the rest of tile is for pilots.

Proposal text (cont) 11.9.2.2.2.1 mapping between HARQ feedback channel and sequence 12 HARQ feedback channel is CDM multiplexed in each UL HARQ feedback region, that is to say,6 times spread in frequency domain and 2 times spread in time domain. Each HARQ feedback channel corresponding one data spread sequence in frequency domain with the length of 6 and one data spread sequence in time domain with the length of 4. Each HARQ feedback channel corresponding one pilot sequence in frequency domain with the length of 6 and one pilot sequence in time domain with the length of 4. is chosen one of the 6 orthogonal sequence in , is chosen as one of the 2 orthogonal sequence in , is chosen as one of the 6 orthogonal sequence in , is chosen as one of the orthogonal sequence in

Proposed text (cont) Figure 4 Tile structure in DLRU Figure 5 structure of a tile Figure 6 data and pilot sequence mapping

Proposed Text (cont) 11.9.2.2.2.2 Data spread sequence The generate of is TBD. The choice of from is TBD. The choice of from is TBD. 11.x.2.2.2.3 pilot sequence The choice of from is TBD. The choice of from is TBD.

Proposed Text (cont) 11.9.2.2.2.4 data modulation and sequence mapping The feedback message on th UL HARQ feedback channel of a HARQ feedback region is modulated with BPSK/QPSK signals. Then is spread in the frequency domain firstly as ,and the this sequence is multiplied by before mapping into all subcarrier of the th symbol in the data zone of a tile, so the data modulated in the th subcarrier of the th symbol in the data zone is The pilot frequency sequence is multiplied by before mapping into all the subcarrier of the th symbol in the pilot zone of a tile, so the signal modulated In the th subcarrier of the th symbol in the pilot zone is -------------end of proposed text ---------------- (11.x.2.2.2.9) (11.x.2.2.2.10)