Comments on SFH IE to Support Network Entry for Multi-Carrier MS Document Number: IEEE C802.16m-09/0563 Date Submitted: 2009/03/02 Source: I-Kang Fu, Yih-Shen Chen, Kelvin Chou, Pei-Kai Liao, Paul Cheng MediaTek Inc. Email: IK.Fu@mediatek.com Venue: IEEE 802.16 Session#58 at Vancouver, Canada. Base Contributions: This is base contribution Re: IEEE 802.16m-09/0012, “Call for Contributions on Project 802.16m Amendment Working Document (AWD) Content,” - Comments on P802.16m AWD Purpose: For TGm member discussion and adoption 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. 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General Network Entry Procedure for Multi-Carrier MS • General network entry / initialization procedure for multi-carrier MS based on SDD 19.4.3 General ideas: 1. 2. 3. 4. 5. Common Procedure for Single-/Multi-Carrier MSs Scan for DL available carriers Multi-Carrier MS follow a common network entry procedure as the single-carrier MS Multi-Carrier BS broadcast the cell bar bit in each carrier the same as single carrier mode Multi-Carrier MS select the candidate primary carrier based on cell bar bit MS and BS exchange their multicarrier capabilities during network entry Perform DL Sync. & Ranging again right after completing the common network entry procedure Extended Procedure for Multi-Carrier MSs DL Sync. with a candidate carrier established No Allow Network Entry in candidate carrier? Establish provisioned connections BS assigned carrier > 1? No Yes Yes Obtain the UL parameters of the primary carrier Ranging in the primary carrier BS inform PHY parameters of assigned carriers DL Sync. & Ranging Negotiate basic and multi-carrier capabilities Operational An example to explain general idea (for information) Discussion Issue#1 • When initialization, multi-carrier MS may randomly select one of the fully configured carriers as its candidate primary carrier. It can save much overhead if BS can broadcast which carrier is allowed for network entry. – – – – The basic motivation is for load balancing and prevent unnecessary carrier change This can largely speed up MS scanning and network access Current IEEE 802.16 Rev2 standard already broadcasts 8 bits load information Suggest 802.16m AWD include single bit indication in SFH for the same purpose BS does not broadcast carrier load information Carrier #4 Network entry... Carrier #3 Carrier #2 Carrier #1 BS broadcasts the carrier load information Carrier #4 Multi-Carrier BS MS3 Carrier #3 Carrier #2 Carrier #1 MS4 MS5 MS2 Multi-Carrier BS Multi-Carrier MS MS1 MS1 MS2 MS3 MS4 MS5 Multi-Carrier MS Discussion Issue#2 After common network entry procedure completed through primary carrier, multi-carrier MS has to performance DL sync & Ranging again before enabling multi-carrier transmission. 1. Consider the example as shown in following, where the multi-carrier MS can support 2 carriers and multi-carrier BS can support 4 carriers. – When initial scanning, MS need to scan for the DL A-Preamble transmitted from BS by adjusting the center frequency of its receiver. Multi-Carrier BS Hardware Controller Multi-Carrier MS PHY1 Multiplexer RF1 RF1 PHY3 PHY2 PHY3 Multi-Carrier BS Multi-Carrier BS support 4 carriers across 40MHz radio BW Common MAC PHY2 Hardware Controller Multiplexer Common MAC • 40MHz (4096FFT) PHY4 Frequency Carrier#1 20MHz (2048FFT) Multi-Carrier MS Carrier#2 Carrier#3 Carrier#4 Multi-Carrier MS support up to 2 carriers across 20MHz radio BW. But it only use 10MHz (or less) for initial scanning on A-Preamble. Frequency Discussion Issue#2 2. After the symbol detection and fully configured carrier confirmation, the multicarrier MS may then perform network entry through that carrier. – The center frequency of multi-carrier MS receiver will be the same as the primary carrier because of the time domain symbol detection operation Multi-Carrier BS 40MHz (4096FFT) Frequency Primary Carrier Carrier#1 20MHz (2048FFT) Multi-Carrier MS Carrier#2 Carrier#3 Carrier#4 Multi-Carrier MS will adjust its center frequency be the same as the one of primary carrier when the A-Preamble is detected. Then multi-carrier Frequency MS will complete the common network entry procedure by signaling and messaging through this carrier. Discussion Issue#2 3. After completing the common network entry procedure, the multi-carrier MS have to perform DL sync. & Ranging again before activating secondary carrier. – Because the center frequency of multi-carrier MS transceiver need to be adjusted again so that its BW can cover the radio signals transmitted through both carrier#1 and #2. – After completing the common entry procedure, the MS transceiver BS only cover part of the carrier#2. – It is recommended to do this DL sync. & Ranging right after the common network entry procedure (e.g. after determining the assigned carrier). – Otherwise the MS will need to do this adjustment before activating the assigned carrier and will then disturb the ongoing data transmission in primary carrier. This is really unnecessary. Multi-Carrier BS Frequency 40MHz (4096FFT) Frequency Primary Carrier Carrier#1 Carrier#2 Before activating secondary carrier transmission Carrier#3 Carrier#4 Secondary Carrier Multi-Carrier MS Right after completing common network entry procedure Center Frequency Frequency Summary 1. P802.16m AWD needs to define a common network entry procedure for all MS and an extended procedure only for multi-carrier MS – 2. P802.16m AWD needs to keep single bit indication in SFH of each carrier to help network entry – – – 3. Based on current idea agreed in SDD (19.4.3) Align with the idea in current Rev2 standard design Single bit will be enough Multi-Carrier should select its primary carrier based on this indication Network entry procedure in P802.16m AWD needs to allow DL sync. & Ranging after assigning secondary carriers to MS – – – Align with SDD (r7) description in line#18, page#150. Negotiate some time for multi-carrier MS configure its hardware according to the secondary carriers assigned by BS This action shall be performed before the end of network entry stage rather than right before activating secondary carrier • Time reservation for hardware reconfiguration will still be necessary. If not, it will disturb data transmission in primary carrier. Text Proposal • [Add the following text into P802.16m AWD] 15.3.6.5.1.2.2 S-SFH SP1 IE Table xxx. S-SFH SP1 IE format Syntax Size (bit) Notes S-SFH SP1 IE format () { MSBs of superframe number TBD Part of superframe number S-SFH SP scheduling information TBD SP scheduling bitmap S-SFH SP change bitmap TBD 1 or multiple bits per SP Additional broadcast information indicator TBD HO information (Open BS/Close BS, UL load indicator, cell type) TBD Cell bar access bit Reserved } 1 For uncontrolled HO scenario 0: Allow network entry/reentry 1: MS shall not perform network entry/reentry through this carrier