1. Hybrid Multiple Access for IEEE 802.16m and Its Frame Structure Document Number: IEEE C802.16m-08/027r3 Date Submitted: 2008-1-18 Source: Bang Chul Jung, Junsu Kim, Min Suk Kang, Seonghwan Kim, and Dan Keun Sung E-mail: bcjung@kaist.ac.kr, jskim@cnr.kaist.ac.kr, minsuk.kang@kaist.ac.kr, shkim@cnr.kaist.ac.kr, dksung@ee.kaist.ac.krbcjung@kaist.ac.krjskim@cnr.kaist.ac.krminsuk.kang@kaist.ac.krshkim@cnr.kaist.ac.krdksung@ee.kaist.ac.kr KAIST Re: TGm Call for comments on SDD, IEEE 802.16m-07/047, in the area of “Multiple access and multi antenna techniques, specifically as related to frame structure” Abstract: Discussion on the 16m multiple access (Uplink) scheme and its frame structure Purpose: To discuss the multiple access scheme for uplink of IEEE 802.16m and its frame structure in the 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: 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. 2 Background Dedicated Resource Allocation Scheme Virtual Dedicated Resource Allocation Scheme Scheduling-based Resource Allocation Scheme 2G CDMA/GSM *ORHM/ORHMA Orthogonal Resource Hopping Multiplexing/Multiple Access 3G HSDPA, 1xEV-DO, WiMax Bursty data applications - FTP, HTTP, etc Low latency service for real-time traffic Low latency Small signaling overhead Efficient for medium/low rate traffic SMG (Statistical Multiplexing Gain) High throughput for bursty data traffic MUD (Multi-User Diversity) gain Flexible resource allocation Real-time applications - VoIP, Gaming, Video, etc Inefficient for high rate bursty data traffic No SMG Inefficient for low/medium rate traffic Inefficient for real-time traffic Large signaling overhead Inefficient for high rate traffic Real-time applications Low/medium rate applications - VoIP, Gaming, Video, etc * S. Park, and D. K. Sung, “Orhtogonal code hopping multiplexing,“ IEEE Communications Letters, vol.6, no.12, pp.529-531, Mar. 2002.

3. 3 Hybrid Resource Allocation Scheme Dedicated Resource Allocation Scheme Virtual Dedicated Resource Allocation Scheme Scheduling-based Resource Allocation Scheme Conventional Hybrid Scheme Dedicated + Scheduling-based Resource allocation scheme Simple Combination 3GPP2-UMB System (CDMA + OFDMA) 3GPP-DL (WCDMA:voice + HSDPA:data) 3GPP-UL (WCDMA:voice + HSUPA:data) Proposed Hybrid Scheme Virtual Dedicated + Scheduling-based Resource Allocation Scheme Dynamic Harmonization High throughput for bursty data applications Low latency for real-time applications It is possible to provide a service-oriented resource allocation

4. Multiple Access Scheme –Basically, a scheduling-based OFDMA scheme is being considered for 16m air interface for the legacy support requirements. Scheduling-Based Multiple Access in Legacy 802.16e System

5. Uplink Hybrid Multiple Access (HMA): [Scheduling-Based & Virtual Dedicated Channel-Based Transmission] Scheduling-Based Multiple Access Scheduling-Based Multiple Access Virtual Dedicated Channel-Based Multiple Access Virtual Dedicated Channel-Based Multiple Access Efficient resource management  Accurate MCS level decision  Better spectral efficiency  No inner-cell interference Scheduling procedure is burdensome  High latency Target applications  Bursty data traffic (FTP, HTTP, etc)  High rate traffic No scheduling procedure  Short latency, Low complexity  Small signaling overhead Collisions may occur.  FER degradation  Collisions can be resolved at BS Target applications  Real-time traffic (VoIP)  Low/medium rate traffic Hybrid Multiple Access

6. Case I : Burst-based assignment –UL-bursts are assigned for the virtual dedicated channel based transmission. –The amount of assigned UL-bursts is configurable according to the amount of real-time or low/medium rate application users. –16m legacy support is possible by configuring the amount of the assigned resource. Uplink HMA Frame Structure 6

7. Case II : Zone-based assignment –A new zone can be assigned to virtual dedicated channel based transmission. –The amount of the assigned resource can be configured according to the number of users supported by virtual dedicated channel based multiplse access. Uplink HMA Frame Structure (cont’d) 7

8. We proposed uplink hybrid multiple access (HMA) scheme. –Proposed hybrid multiple access scheme combines virtual dedicated channel based multiple access and scheduling based multiple access schemes. –It is possible to achieve high throughput and low latency using the proposed hybrid scheme. –The proposed hybrid scheme is possible to support various applications having different traffic characteristics. We proposed frame structure for the proposed uplink hybrid multiple access (HMA) scheme. –Dynamic resource assignment to each multiple access scheme is possible according to the amount of the generated traffic. –The proposed frame structure can achieve the16m legacy support requirement. Conclusions 8

9. Persistent Scheduling –Resource inefficiency problem Resource can be wasted when a user is deallocated or reallocated according to the silence period or change in MCS. –Complexity/Overhead problem Deallocation/reallocation procedure should be performed at start of every silence period and talk period. Virtual Dedicated Allocation –Efficient resource allocation Hopping pattern allocation increases the resource efficiency due to the channel activity of each user. –Reduced control overhead and complexity Users transmit their data according to the pre-allocated hopping pattern. Comparison of Persistent-Scheduling and Virtual Dedicated Allocation [Appendix-A] Comparison of Persistent-Scheduling and Virtual Dedicated Allocation 9

10. Resource Hopping Example of ORHMA [Appendix-B] Resource Hopping Example of ORHMA 10 SC#3SC#1SC#5SC#4SC#6SC#8SC#3 SC#2SC#1 SC#3 SC#8SC#6SC#3SC#4 SC#7SC#2 SC#5SC#4SC#3 SC#4SC#5SC#9SC#8SC#2 SC#3SC#7SC#6SC#5SC#6SC#9SC#1 : ON data symbol : OFF symbol duration Random frequency (subcarrier) hopping is assumed. Resource hopping increases resource efficiency and statistical multiplexing gain (green blocks). Link performance degradation occurs due to resource collision (red blocks). User #a User #b User #c User #d