1. C80216m-08_216 ProjectIEEE 802.16 Broadband Wireless Access Working Group http://ieee802.org/16 TitleDownlink Physical Resource Allocation Unit Date Submitted 2008-03-10 Source(s)Sean McBeath, JueJun Liu, Jianmin Lu Huawei E-mail: smcbeath@huawei.com Re:IEEE 802.16m-08/005: Call for Contributions on Project 802.16m System Description Document (SDD). Target topic: “ Downlink Physical Resource Allocation Unit ”. AbstractProposal for downlink physical resource allocation unit PurposeFor discussion and approval by TGm 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. C80216m-08_216 2 Introduction The basic resource allocation block is a fundamental design consideration for OFDMA systems The size of the basic resource allocation block impacts the following: –Capacity If the resource block is too large, the capacity for applications such as VoIP will be limited –Assignment Message Overhead If the resource block is too small, there will be unnecessary overhead in the assignment messages –Control Signal Overhead Depending on the design, the number of resource blocks may be related to the number of resources needed for the acknowledgment channel

3. C80216m-08_216 3 VoIP Consideration For VoIP, it is desirable for an integer number of resource blocks for QPSK to have an approximate effective coding rate of 1/2 –A spectral efficiency of 1 is the most common in system simulations While the evaluation methodology uses the AMR vocoder, we should design the system to effectively support EVRC as well AMR We should consider a reduced MAC header when analyzing the basic resource allocation block size

4. C80216m-08_216 4 QPSK Effective Coding Rate

5. C80216m-08_216 5 QPSK Effective Coding Rate

6. C80216m-08_216 6 Conclusion For VoIP, the number of traffic symbols times subcarriers in an integer number of resource blocks should be between 220 and 348 –For 6 OFDM symbol mini-frames, assuming 20% overhead for pilot and control, the following table represents the number of traffic symbols times subcarriers for various number of resource blocks.

7. C80216m-08_216 7 Conclusion –Recommendation: 12x6 or 18x6 –The tables below show the effective coding rate for the first HARQ transmission assuming 20% of the resource block is used for pilot and control (QPSK) AMR EVRC

8. C80216m-08_216 8 Proposed Text Insert the following text into Physical Layer sub-clause (IEEE C802.16m-08/003): ------------------------------- Text Start --------------------------------------------------- 11.1 Downlink Physical Resource Allocation Unit The downlink physical resource allocation unit shall be 12 subcarriers by 6 OFDM symbols or 18 subcarriers by 6 OFDM symbols. ------------------------------- Text End ---------------------------------------------------