1. Proposal for advanced interleaving in IEEE 802.16m Document Number: IEEE C802.16m-11/317 Date Submitted: 2007-11-11 Source: Venue: IEEE 802.16 Session #52 Atlanta, United States Base Contribution: None Purpose: Response to SDD Call for Proposal of 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 IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs 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: and.http://standards.ieee.org/guides/bylaws/sect6-7.html#6http://standards.ieee.org/guides/opman/sect6.html#6.3 Further information is located at and.http://standards.ieee.org/board/pat/pat-material.htmlhttp://standards.ieee.org/board/pat

2. Abstract After the Channel encoding and the IFFT transformation, it is necessary to scramble (interleave) the data that will be placed on the sub-carriers of the OFDM symbol. This interleaving operation is split into two phases: –A bit interleaving is applied on a FEC block. –A frequency interleaving is applied on the data symbols before they are mapped on the sub-carriers. This document presents a rationale for these two types of interleaving and the gain they bring to the system.

3. Modulator Block Diagram Encoder Puncturer Bit Interleaver QAM Mapper iFFT Window & GI RF Pilots & null Frequency Interleaver

4. 802.16 PUSC Permutation Distribution of data symbols of a sub- channel not uniform!

5. Block interleaving proposal [1][2][3] Structure A unique mathematical algorithm – Generate block interleaving with a size K Permutation based on: –2 integer parameters {p,q} –Iterative structure with j iterations Procedure Divide block into sub-blocks of length p, K=pm x 0 x 1 x 2.. …x p-1 x p x p+1 … x 2p-1 x p(m-1) x 1+p(m-1) x 2+p(m-1) … x pm-1

6. Block interleaving proposal (2) Conservation of a sample interleaving pattern p p is a parameter of the interleaver (submultiple of K) Maximize interleaving spreading I(s) -Between adjacent sub-carriers and sub-channels x 0 x 1 x 2.. …x p-1 x p x p+1 … x 2p-1 x p(m-1) x 1+p(m-1) … x pm-1 x' 0 x' 1 x' 2 x' 3 …x' p-1 x' p x' p+1 ….x' 2p-1 x' p(m-1) x' 1+p(m-1) … x' pm-1 S=1 S=p

7. Frequency permutation proposal Interleaving spreading maximisation between sub-channels (s=24) and between sub-carriers close {p,q,j} values Optimized permutation rule :K=720 p=12,q=2, j=1 Distance (s) FTR&D proposal I(s) 802.16e PUSC I(s) 1 311 46 2 98 46 4 213 47 24 264 210

8. Bit interleaving Same algorithm as frequency interleaver Optimum values: {p,q,j}={36,2,1} for coded size = 576 Provides high interleaving spreading: 217 Distance (s) FTR&D proposal I(s) 802.16e I(s) 1217 37 2142 72 275 109 3284 144

9. Simulation results

10. Simulation environment Downlink FFT size : 1024 Guard sub-carriers: 93 on the left side, 82 on the right side DC sub-carrier: 1 Pilots: 120 Data sub-carriers: 720 Sub-channel size: 24 data symbols Block size: 576 Channel coding: CTC Channel model: 3GPP Macro Urban

14. Conclusions An unique mathematical algorithm for both binary and frequency interleaving for OFDM/OFDMA schemes Increases the distance between adjacent bits and adjacent carriers to enhance performance There is no additional complexity to system – Only the interleaving matrix required Interleaving in 802.16 can be improved need to define a selection process for advanced interleavers

15. References [1] Siaud.I, Ulmer-Moll A.M, "A Novel Adaptive sub-carrier Interleaving : application to millimeter- wave WPAN OFDM Systems (IST MAGNET project)", IEEE portable 2007 conf, 25-29 March 2007, Orlando (USA). [2] Siaud.I, Ulmer-Moll, "Advanced Interleaving algorithms for OFDM based millimeter wave WPAN transmissions", SCEE Seminar, 8 February 2007, France. [3] Siaud.I, Ulmer-Moll A.M, P. Desmoulin, "A novel HiperMAN OFDM/OFDMA PHY dynamic sub- carrier mapping algorithm based on a dynamic turbo-structure interleaving (Version V.2) ", ETSI BRAN #44, document d032, February 2006. [4] I. Siaud, J. Benko, full band diversity interleaving, IEEE 802.22 0242-00-0000 [5] P. Pagani, M. Piz, I. Siaud, E. Grass, et al., "France Telecom - IHP Joint Physical Layer Proposal for IEEE 802.15 Task Group 3c", IEEE 802.15 Working Group for WPAN, no. IEEE 802.15- 07/689r0, May 2007. [6] 3GPP TR 25-996 v6.1.0 Spatial channel model for Multiple Input Multiple Output (MIMO) simulations