IEEE 802 Meeting會議報告

Transcription

會議報告（會議類別：其他）
IEEE 802 Wireless Session #148 Meeting 會議報告
出席人員：方士豪
派赴地區：美國/聖安東尼(San Antonio)
會議期間：103 年 11 月 3 日至 103 年 11 月 7 日
報告日期：103 年 12 月 30 日
摘要
IEEE 802 Wireless Session #148 標準制定會議於美國德州的聖安
東尼舉行。由於本會期是 Plenary Session，因此會議與其他 IEEE 802
的 Working Group (802.1、802.3、802.15、802.16、802.18、802.19、
802.21、802.22)及 Study Group (SG ECSG)同時舉行；本次會議舉行
的地點為 Grand Hyatt San Antonio 飯店，時間由 2014 年 11 月 3 日至
11 月 7 日共計 5 天，而 IEEE 802.11 TGax 會議主要集中在前四天
11/3-11/6 舉行，最後一天 11/7 則舉行會議 Closing Plenary。本次到美
國德州聖安東尼市的主要目的是掌握最新一代無線通訊網路標準
IEEE 802.11 TGax High Efficiency Wireless (HEW) 在 Physical Layer
之技術發展近況。
本會期的 IEEE 802.11 TGax 會議，所討論的範圍主要還是在
Physical Layer 與 Media Access Control (MAC) Layer 兩大部分，而議
題還是圍繞在原先成立 Study Group 的目標，即如何提升 802.11
Physical Layer 與 MAC Layer 在 2.4GHz 與 5GHz 之頻譜效益(Spectrum
Efficiency)與 Area Throughput，除此之外也著重在如何提升室內與室
外之效能。細部的議題主要包含 Evaluation Methodology、Simulation
Scenarios 與 Calibration、Specification Framework 與一些 MU-MIMO
和 OFDMA 相關技術，而初版的 IEEE 802.11ax Specification
Framework 也在本會期中投票通過，之後標準規格文件將會根據此版
本修訂。會議中除了 Physical Layer 的相關議題，MAC Layer 的議題
也在會議中提出討論。除了標準制定會議之外，大會也準備兩個
Tutorial 讓參與的成員參加，了解目前相關技術發展的近況。
2
技術貢獻
本次會議的主要目標是追蹤 802.11 工作群組之發展情形，即時
掌握目前 802.11 標準會議中，各家科技公司最新技術之近況，並沒
有提案產出。
會議解說
本次 IEEE 802 Wireless Session #148 會議於美國聖安東尼舉行，
會議內容主要可以分成上述幾種標準制定會議，本次主要是選擇參與
最多人的 IEEE 802.11 TGax 會議。由於 TGax 會議人數較多，因此也
包含了許多廠商或公司人員來進行提案討論。每次相關人員提案後，
其他公司人員皆會進行相關技術的詢問與挑戰，由此可見各家廠商或
公司對於此次標準制定會議之重視。
3
與會成員工作分配
與會成員
任務
追蹤 802.11 TGax(HEW, High Efficiency Wireless)
方士豪
之 Physical Layer 技術進展
4
目
錄
摘要...........................................................................................................2
技術貢獻.....................................................................................................3
會議解說.....................................................................................................3
與會成員工作分配 ....................................................................................4
一、會議名稱 ............................................................................................6
二、參加會議目的及效益 ........................................................................6
三、會議時間 ............................................................................................6
四、會議地點 ............................................................................................6
五、會議議程 ............................................................................................7
六、會議紀要 ..........................................................................................18
七、心得與建議 ......................................................................................34
5
一、會議名稱

IEEE 802 Wireless Session #148 Meeting
二、參加會議目的及效益

參與 802.11 工作群組會議，針對最新提案議題進行討論與蒐集。

參加 Tutorial 了解最新市場應用趨勢
三、會議時間

November 3, 2014 ~ November 7, 2014
四、會議地點

美國/聖安東尼(Grand Hyatt San Antonio, San Antonio, USA )
五、會議議程
表一列出了 IEEE 802.11 之議程表，且詳細的議程列於表二。
表一：IEEE 802.11 Wireless 議程表
表二：IEEE 802.11 TGax議程表
日期
時間
詳細描述







Monday
November 3
Call meeting to order
Patent policy, etc.
Call for submissions
Set and approve agenda for Ad Hoc meeting
Presentations
 11-14-1380-00-00ax-efficiency-measurement-for-r
8:00-10:00




ts-cts
11-14-1381-01-00ax-novel-rts-cts
11-14-1382-00-00ax-responses-to-the-comments-o
n-doc1169
11-14-1403-00-00ax-performance-analysis-of-bsscolor-and-dsc
11-14-1404-00-00ax-11aa-gcr-ba-performance-inobss
11-14-1441-00-00ax-simulation-setting-of-box5-ca
libration
Adjourn
802.11 Working Group Opening Report
1. Opening formalities
 Meeting called to order
 Front table introductions. Introduce IEEE-SA staff
representative
 Courtesy Notice
 Review and approve 802.11 session agenda
 Review and approve WG minutes - Beijing
 Straw poll of new attendees
2. Announcements
 Policies and procedures
 Review Patent Policy slides
 Inform participants of the following P&Ps
 IEEE Code of Ethics





Monday
November 3
IEEE Standards Association (IEEE-SA) Affiliation
FAQ
IEEE-SA Antitrust and Competition Policy
IEEE-SA Letter of Assurance (LoA) form
11:00-12:30

IEEE-SA Patent Committee (PatCom) information
IEEE 802 LAN/MAN Standards Committee
(LMSC) P&Ps, Chairs Guidelines, Operations
Manual
 IEEE 802 LMSC WG P&P
 IEEE 802 LMSC rules changes
 IEEE 802.11 Operations Manual - review changes
 Reflectors
Incoming Liaisons
 Summary of new and pending liaisons and

processing this weekITU-R WP5a request for
information
Other Anouncements
3. Logistics and Key events/activities
 Working group session documents
 Joint meetings & Reciprocal Credit
 Other WG meeting plans
 Meeting room locations
 Next meeting reminder

Meeting registration
8





Recording attendance
File server
Breakfast, breaks, BoF logistics
Wednesday Topics
Report on 802 EC or IEEE-SA Standards Board
decisions
4. Opening reports, objectives & plans
 WG reports
 802.11 groups







802.11 PARS
Officers
Standards pipeline and 802.11 revisions
Summary of Ballots / Comment collections
WG membership summary




WG ANA report
WG Treasurer's report
WG timeline report / planning
WG technical editor
Standing committee reports
 Architecture (ARC) (including 802 Architecture
status)
 PAR
 Publicity (PUB)
 Regulatory (REG)
 Wireless Next Generation (WNG)
 JTC1 802 SC
Task Group reports
 TGmc - Revision mc (REVmc)







TGah - Sub 1 GHz (S1G)
TGai - Fast Initial Link Setup (FILS)
TGaj - China Millimeter-Wave (CMMW)
TGak - General Link (GLK)
TGaq - Pre-Association Discovery (PAD)
TGax - High Efficiency Wireless LAN (HEW)
Study Group reports
5. Recess
9





Monday
November 3
16:00-18:00

Call meeting to order
Patent policy, etc.
Set and approve agenda
Summary from September 2014 meeting
 Elected TG vice chairs as scheduled.
 Approved the first revision of the functional
Requirements document
 Generated new revision of the TG documents
based on motions passed during the meeting.
 Technical presentations
SG motions
 Approve TG meeting and Telecon minutes since
September meeting.
Presentations


11-14-1388-01-00ax-consideration-on-per-predicti
on-for-phy-abstruction
11-14-1392-01-00ax-simulation-results-for-box-5calibration


11-14-1418-01-00ax-further-study-of-time-varying
-interference-and-phy-abstraction
 11-14-1419-00-00ax-sls-box5-calibration-results-a
nd-discussions
 11-14-1420-01-00ax-the-impact-of-preamble-error
-on-mac-system-performance
Recess

Tutorial 1: Gigabit Ethernet Over Plastic Optical
Fiber (GEPOF)
 Overview of proposed p802.3bv project
 Technical / Economic Feasibility
 Home networking market
 Automotive market
 Industrial market
 Support
Monday
November 3
18:00-20:00

Tutorial 2: Introduction to P802.3bn EPON Protocol
over Coax (EPoC)
 Introduction

Motivation for EPoC
10


 P802.3bn overview
 EPoC Application
 Overview of Challenges
Cable Network Requirements
 Terms
 EPoC Topologies
 RF Spectrum availability and flexibility
 Common component architecture elements
PHY Link Channel






Call Meeting to order

IEEE 802 and 802.11 IPR Policy and procedure.

Presentations
 11-14/1434, “SLS Box4 Calibration Results”,


Tuesday
November 4

10:30-12:30




Tuesday
November 4
13:30-15:30
What it is, why we need it
DS PHY Link
US PHY Link
CNU bring up
PHY Link Tasks
Russell Huang (MediaTek Inc.)
11-14/1444, “Energy Efficiency Evaluation and
Simulation Model”, Chinghwa Yu (MediaTek)
11-14/1402, “Box1 and Box3 calibration results”,
Masahito Mori (Sony)
11-14/1342, “MAC Calibration Results”, Igor Kim
(ETRI)
11-14/1343, “Multicast Scenarios for MAC
Calibration”, Igor Kim (ETRI)
11-14/1449, “MAC Calibration Results”,
Newracom
11-14/1450,” box 0 calibration results”, Hongsup
Lee (Newracom)
11-14/1451, “box 1 and box 2 calibration results”,
Jaehyun Ahn (Newracom)

Recess



Presentations
11






Recess



Presentations
 11-14/1397, “Discussion on Frame Structure for
Future WLAN Systems with OFDMA”,

16:00-18:00




Wednesday
November 5
10:30-12:30
11-14/1428, “Clear Channel Assessment for
OFDMA PHY”, K. C. Chen (NTU) and D. J. Deng
(NCUE)

Tuesday
November 4
11-14/1426, “DSC and legacy coexistence”,
Gustav Wikstrom et al. (Ericsson)
11-14/1427, “DSC Performance”, Gustav
Wikstrom et al. (Ericsson)
11-14/1443, “Adapting CCA and Receiver
Sensitivity”, Esa Tuomaala (Nokia)
11-14/1448, “Considerations for Adaptive CCA”,
Reza Hedayat (Newracom)
11-14/1446
Myeong-Jin Kim (Korea University)
11-14/1431, “Issues on UL-OFDMA”, Young
Hoon Kwon (Newracom)
11-14/1433, “Protocol and signaling framework
for OFDMA”, Sigurd Schelstraete (Quantenna)
11-14//1442, “Considerations on DL OFDMA
control mechanism”, Woojin Ahn (Yonsei Univ.)
11-14/1452, “Frequency selective scheduling in
OFDMA”, Leif Wilhelmsson (Ericsson)
Recess
802.11 Working Group Mid-Week Plenary
 Front Table introductions
 Modify and approve modifications to agenda
2. Announcements
 Policies and Procedures (P&P) reminder
 Call for essential patents

Reminder of Thursday night CAC meeting
12


EC workshop description
Any other announcements
3. Old business
 Any WG reports carried forward
4. Reports by 802.11 liaisons officers
 External (non-802) liaisons
 WiFi Alliance (WFA)
 Internet Engineering Task Force (IETF)
 Internal (802) liaisons

Briefing on Coexistence Lessons Learned (802.19)
activity
5. New business
 Room change requests & Graphic update
 Briefing on attempts to improve relationship with the




WFA
Study Group formation for Next Generation Positioning
Request for Guidance on rules for allocation of last
Element IDs
IEEE 802.3 Next Generation Enterprise Access
BASE-T PHY call for interest
Discuss 802.11 response to 802c PAR
6. Recess



Presentations
 11-14/1417, “HEW PPDU Transmission
Discussion” Yongho Seok (NEWRACOM)

Wednesday
November 5
13:30-15:30



11-14/1436, “Overhead Analysis for Simultaneous
Downlink Transmissions”, Pengfei Xia
(interdigita)
11-14/1437, “Efficient Wider Bandwidth
Operation in IEEE 802.11a”, Jinsoo Ahn (Yonsei
Univ)
11-14/1439, “Preamble Considerations in Large
Channel Delay Spread Scenarios”, Daewon Lee
(Newracom)
11-14/1228, “Issues on 256-FFT per 20MHz”,
Heejung Yu (NEWRACOM/YU)
13



Recess



Presentations
 11-14/1429, “Proposed 802.11ax specification
framework document”, Minho Cheong
(Newracom)
 11-14/1432, “Proposed 802.11ax specification
Thursday
November 6
11-14/1531, “Empirical open-air VHT client
scaling results for use in validating MAC
simulators” Chuck Lukaszewski (Aruba Networks)
11-14/1496, “Power-Save-Calibration-Scenario”,
Jarkko Kneckt (Nokia)
08:00-10:00


framework – background”, Minho Cheong
(Newracom)
11-14/1453, “Spec Framework Proposal” Robert
Stacey (Intel)
11-14/1447, “Proposed Spec Framework
Document for 11ax considering potential tech
features”, John Son (WILUS Institute), Young Doo
Kim (SK Telecom)

Recess



Ad Hoc Chairs Election
 Election will be on Tuesday during January
meeting
Thursday
November 6

Start time for the Ad Hoc groups
 Ad hoc group meetings to start on March 2015

Editor appointment (Robert Stacey)
 11-14/1523, “Offline Discussion Minutes of SLS
Calibration” Jiyong Pang (Huawei)

TG Motions

Goals for January 2015

Telecon Schedule
13:30-15:30
14

Adjourn
802.11 Working Group Closing Plenary
 Front Table introductions
 Modify and approve modifications to agenda
2. Announcements
 Policies and Procedures (P&P) reminder
 Call for essential patents
Friday
November 7
8:00-10:00
 Reminder to get minutes to WG secretary
 Reminder to get objectives & agendas for next
session to WG Chair by 1st CAC telecon
 Letters of Assurance (LoAs) received
 Drafts for Sale in IEEE Shop
 Drafts to liaise with ISO/JTC1/SC6
 Treasurer's Report
3. Closing Report
 Working Group
 Attendance report
 Straw Poll of membership regarding this meeting
location
 Future venues insight
 PAR review SC report
 Timeline
 WG Editor

 Architecture (ARC)






PAR
Publicity (PUB)
Regulatory (REG)
Wireless Next Generation (WNG)
JTC1 802 TAG
Task Group reports
 TGah - Sub 1 GHz (S1G)
 TGai - Fast Initial Link Setup (FILS)


TGaj - China Millimeter-Wave (CMMW)
15



Study Group
 NG60 - Next Generation 60 GHz

Liaison
 802.15 liaison report
 802.18 RR TAG liaison report


802.24 liaison report
802.1CF (OmniRAN) Status Update
4. Opening reports, objectives & plans
 WG reports
 802.11 groups






802.11 PARS
Officers
Standards pipeline and 802.11 revisions
Summary of Ballots / Comment collections
 WG membership summary
 WG ANA report
 WG Treasurer's report
 WG timeline report / planning
 WG technical editor
 Architecture (ARC) (including 802 Architecture
status)
 PAR
 Publicity (PUB)
 Regulatory (REG)
 Wireless Next Generation (WNG)
 JTC1 802 SC
Task Group reports
 TGah - Sub 1 GHz (S1G)
 TGaj - China Millimeter-Wave (CMMW)
 TGak - General Link (GLK)

16


Study Group reports
5. Motions (old business)
 Working Group motions
 Telecon schedule
 Operations Manual approval

Standing committee motions
 Architecture (ARC)
 PAR





Task Group motions
 TGah - Sub 1 GHz (S1G
 TGaj - China Millimeter-Wave (CMMW)




Publicity (PUB)
Regulatory (REG)
Wireless Next Generation (WNG)
JTC1 802 TAG
Study Group motions
 NG60 - Next Generation 60 GHz
6. New business
 Discussion and decision on use of remaining
"short" Element IDs
 Proposal to use EPD for 5.9 GHz
 Possible request for legacy Element IDs
7. Closing formalities
 Reminder about wireless chairs meeting
 Next meeting reminder
 Adjourn
8. Recess
17
六、會議紀要
6.1 Evaluation Methodology 議題討論
1
11-14/1388, “Consideration on PER prediction for PHY abstruction”, Bo
Sun (ZTE Corp)
 總覽

在 PHY Abatraction 的方法中，目前 RBIR-based 的方法已經放入 Evaluation

Methodology 文件中。
目前有兩個議題需要解決
 議題 1: When an A-MPDU consists of multiple sub-frames, packet error rate
for each sub-frame should be estimated separately to allow the block ACK
for each sub-frame.
 議題 2: The preamble error model and mapping rules should be defined for
PHY abstraction simulation calibration.
 摘要

提出針對 Issue 1 之解法步驟：
 步驟 1: Predict PER(i, *) with the interference event i based on the
block-wised PHY abstraction
 步驟 2: Generate PER(*, j) of sub-frame j from the set of PER(i, *) with the
interference events happened within the duration of the sub-frame j.
 前提與假設：



There are I interference events overlapping with the target PSDU
transmission. The i-th interference event starts from Ti and lasts for
LIF (i) OFDM symbols.
There are J A-MPDU sub-frames included in the PSDU and the
j-th sub-frame lasts for LSF (j) OFDM symbols.
定義：
18

L(i, j) as the number of OFDM symbols in the j-th A-MPDU
sub-frame that overlaps with the i-th interference event, then
 步驟 3: Determine whether a sub-frame j is received correctly
 步驟 4: Determine whether the PPDU is valid

提出針對 Issue 2 之多種解法
 選項 1: Preamble decoding modeled as a sub-frame decoding

Take the whole preamble as a standalone sub-frame with a special MCS
 The PHY abstraction in [1] can be used for preamble PER prediction
 選項 2: The impact of preamble decoding error modeled as additional
AWGN factor
 選項 3: Preamble decoding error modeled based on SINR threshold


Set a preamble error SINR threshold T
If SINR < T, preamble decoding fails and the PPDU receiving fails;
otherwise, the PPDU receiving error is calculated as defined in current
PHY abstraction
 選項 4: Mixed error model



Directly use RBIR PHY abstraction for signaling field PER prediction
with specific MCS and symbol length.
The channel estimation error by LTFs is modeled as additional AWGN
factor
The impact of STF receiving process is ignored.
 結論


本 Contribution 提出了 A-MPDE PER 的 Prediciton 方法
另外也提出了多種 Preamble Decoding Error 模型的方法
19
11-14/1418, “Further Study of Time Varying Interference and PHY
Abstraction” Yakun Sun (Marvell)
 總覽


一些基本的如何 Model Time-Varying Interference 的 PHY Abstraction 程序已經
在之前的文件中討論
本 Contribution 提出了關於 Time-varying intereference 更進一步的探討
 摘要

以下提供了多種必須要 modeling 時變 interference 的因素

 How often a MPDU sees time-varying interference?
 How large the interference level changes?
本 Contribution 蒐集了一些藉由 intergrated 的系統模擬所得到的 interference
的統計資訊
模擬結果分析

 Time varying interference experienced by a subframe is not negligible.
 The issue becomes more significant if spatial reuse is under consideration.
 It is important to handle the time-varying interference accurately.
Residential, 4STA/apartment
1
0.9
0.8
0.7
0.6
CDF
2
0.5
0.4
0.3
Inter-BSS CCA=-82dBm
Inter-BBS CCA=-62dBm
0.2
0.1
0
0
5
10
15
20
25
30
35
40
45
Ratio of the Strongest/Weakest Interference per Subframe(dB)
20
50
Residential, 4STA/apartment
1
0.9
0.8
0.7
CDF
0.6
0.5
0.4
0.3
Inter-BBS CCA=-62dBm
0.2
0.1
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Relative Duration of the Strongest Interference in a Subframe
1
 結論


從系統模擬層級的模擬可看出，在 subframe 之內的 interference change 是不
可以忽略的。
一個更精準的 PHY Abstraction 方法必須要提出並可以處理 Time-varying
interference。
21
6.2 Simulation Scenarios Calibration 議題討論
1
11-14/1441, “Simulation Setting of Box5 Calibration”, Jiyong Pang
(Huawei)
 總覽

本 Contribution 提供了 Box-5 Calication 的模擬結果
 摘要

Box-5 Calibration 概要說明
 Box 0, 1, and 2 calibration are almost done
 Box 3 calibration is now in progress
 Box 5 calibration was initially discussed in September meeting
 Box 5: Integrated system simulator calibration


The objective is to align a combination of all PHY and MAC features
Box-5 MAC 細部參數資訊
22

Box-5 PHY 細部參數資訊

11ac Scenario 6 – OBSS Enterprise
30
BSS A STA locations
BSS B STA locations assuming (xb,yb)=(40,20)
BSS C STA locations assuming (xb,yb)=(-40,-20)
20
27
15
21
10
8
11 2
23
5
29
9
3
26
4 10
0
14
20
1319 22
728
25
16
17
1
-10
12
6
24
30
18
-20
-30
-50
-40
-30
-20
-10
0
23
10
20
30
40
50

Traffic Flow 模型
 DL/UL traffic assigned for each STA

One BSS 測試結果
 BSS B (STAs 3, 9, 15, 21, 27)
24

觀察結果描述




DL throughput shows uniform distribution
AP power is enough for fully supporting MCS 7
UL throughput is determined by distance from AP
UL total throughput shows 13.8% of performance degradation over DL total
throughput because of collisions and lower TX power
 結論

本 Submission 提供了一些 Box 5 的 Calibration 結果供各公司參考
25
2
11-14/1434, “SLS Box4 Calibration Results”, Russell Huang (MediaTek
Inc.)
 總覽

Box 4 測試回顧
 Box 2 test 3 + Box 0 (PHY abstraction) + MCS selection
 PHY abstraction includes
 Effective SINR via RBIR
 PER from effective SINR
 Output
 Per-STA throughput
 Per-STA selected MCS
 Per-STA airtime
 SINR (effective SINR via RBIR)
 摘要

Box 4 測試 Overview
 RBIR -> Effective SINR -> PER (only payload included with PSDU size




1500 bytes)
LDPC and BCC included
MCS selection (max throughput)
Box 2 Transmission selection algorithm, CCA threshold -70
輸出結果

 SINR CDF (effective SINR via RBIR after MCS selection)
 Per-STA throughput CDF(only for UL)
SS1 之 CDF 曲線

SS2 之 CDF 曲線
26

SS3 之 CDF 曲線

SS4 之 CDF 曲線

注意事項
 Per-STA throughput CDF curves are relatively smooth because
 Throughput is defined as (1-PER)*R
 Time averaged
 0-thoughput STAs exist due to not enough transmissions
 Curves do not converge when transmissions are not enough
 SINR curves being odd might be caused by MCS selection, table look-up, or
not enough drops. To be investigated.
 結論


Throughput 的曲線可提供一個基本的 Calibration 結果
MCS 選擇使得 SINR 看起來與 Box 2 的結果不盡相同
27
6.3 OFDMA 議題討論
1-14/1397, “Analysis of frequency and
UL-OFDMA”, Leif Wilhelmsson (Ericsson)
power requirements
for
 總覽


頻率錯誤與 Near-far 影響會使 UL-OFDMA 系統有嚴重的效能損失
本 Contribution 提供了一些 UL-OFDMA 之模擬分析結果，可提供各公司參考
 摘要

單一使用者情況之 ICI
 For relatively small CFO errors, the SNR degradation due to ICI is
well-approximated by the commonly used expression as follows

The total ICI on the N2 subcarriers of u2 may then be expressed as
14
12
64-QAM
16-QAM
QPSK
10
SNR Degradation (dB)
1
8
6
4
2
0
0
0.5
1
1.5
2
2.5
3
3.5
Relative Frequency Error (% of carrier spacing)
28
4
4.5
5

在 AP 端，Degradation 與 frequency offset 之比較
5
Dc , PR = 10dB
4.5
Dc , PR = 5dB
Dc , PR = 0dB
4
Dc , PR = -5dB
SNR Degradation (dB)
3.5
Dc , PR = -10dB
Ds
3
2.5
2
1.5
1
0.5
0
-2

-1.5
-1
-0.5
0
0.5
1
1.5
Relative Frequency Error (% of carrier spacing)
2
2.5
3
Power 與 Frequency 之 Joint 需求
10
9
Frequency Error (% of carrier spacing)
8
7
6
5
4
3
2
1
0
-10
0.5dB, 64-QAM
1dB, 64-QAM
2dB, 64-QAM
3dB, 64-QAM
0.5dB, 16-QAM
1dB, 16-QAM
2dB, 16-QAM
3dB, 16-QAM
0.5dB, QPSK
1dB, QPSK
2dB, QPSK
3dB, QPSK
-5
0
5
Power Ratio (dB)
10
15
20
 結論

若使用單一使用者之 OFDM 系統，並不能在 OFDMA UL 情況下直接計算
MUI，因為所有的子載波皆假設含有相同的 Frequency Error，且 Power 也假
設相同。

一般化 OFDMA 系統是一種很直接的方法，而且可以使得計算效能損失變得
比較容易。
29
2
11-14/1397, “Discussion on Frame Structure for Future WLAN Systems
with OFDMA”, Myeong-Jin Kim (Korea University)
 總覽

本 Contribution 討論了 OFDMA 系統中之 Frame Structure，可以使得 WLAN
系統的效能得到提升。
 摘要

為了使 Serve 使用者具有不同的 Link Quality，以下的 TXVECTOR 的特定參
數將會被使用者使用：





MCS: indicates the modulation and coding scheme
NUM_STS: indicates the number of space-time streams
STBC: indicates whether STBC is used
FEC_CODING: indicates which FEC encoding is used
以下提供了一種 Frame Structure 的例子
 To assign control channel which is separated from data subchannels
 結論

本 Contribution 討論了 OFDMA 系統的 Frame Structure

提出了一個 OFDMA 系統中的 Frame Stucture 例子
30
11-14/1452, “Frequency
Wilhelmsson (Ericsson)
3
selective
scheduling
in
OFDMA”,
Leif
 總覽



從之前的 Work 可得到，Frequency Selective Scheduling 可以提升 Throughput
為了得到 Scheduling 的 Gain，我們必須要在 AP 端得到精確的通道資訊
本 Contribution 呈現了對於 Frequency Selective Scheduling 的 initial 的一些模
擬結果
 摘要

單一使用者之 Potential gain
 “Channel model D*” and ideal channel knowledge at AP assumed
2.2
120
freq. select. scheduling
random scheduling
fixed subband
2
random scheduling
100
1.6
Throughput gain(%)
Average rate(bps/Hz)
1.8
1.4
1.2
1
0.8
80
60
40
0.6
20
0.4
0.2
0
5
10
15
20
0
25
0
5
10
SNR(dB)
15
20
25
SNR(dB)
 Figures show potential gain vs. delay spread for SNR = 10 dB and ideal
channel knowledge
70
1.1
1.05
60
1
Throughput gain(%)
50
0.95
random scheduling
fixed subband
0.9
0.85
0.8
random scheduling
40
30
20
0.75
10
0.7
0
0.65
0
20
40
60
80
100
Delay spread(ns)
120
140
-10
160
31
0
20
40
60
80
100
Delay spread(ns)
120
140
160

4 個使用者之 Potential gain

“Channel model D*” and ideal channel knowledge at AP assumed
8
35
random scheduling
fixed subband
7
random scheduling
30
25
Throughput gain(%)
6
5
4
3
15
10
2
5
1
0
20
0
5
10
15
20
0
25
0
5
10
SNR(dB)
15
20
25
SNR(dB)
 Figures show potential gain vs. delay spread for SNR = 10 dB and ideal
channel knowledge
3.3
25
random scheduling
fixed subband
3.2
20
Throughput gain(%)
3.1
3
2.9
2.8
15
10
5
2.7
0
2.6
2.5
random scheduling
0
20
40
60
80
100
Delay spread(ns)
120
140
-5
160
32
0
20
40
60
80
100
Delay spread(ns)
120
140
160

具有通道變化之 Initial 模擬結果
22
20
Throughput gain(%)
18
16
14
12
10
ideal
1ms delay
2.5ms delay
5ms delay
8
6
0
10
20
30
Doppler spread(Hz)
40
50
 結論


Frequency-selective scheduling 可以提供單一使用者或多個使用者額外的增益
不精準的通道資訊會導致 Scheduling 的效能損失，但是日後 802.11ax 應該還
是會採取此方法，因為會得到額外的好處
33
七、心得與建議
本次會議主要是參加IEEE 802.11 Working Group中Task Group ax相關議
題之討論，此Task Group主要討論的議題還是圍繞在當初Study Group的目標，
即如何提升802.11 Physical Layer與MAC Layer在2.4GHz與5GHz之Spectrum
Efficiency與Area Throughput，除此之外也著重在如何提升室內與室外之效
能。從會議中可看出，目前世界各大科技公司(Intel、MediaTek、Nokia、
Qualcomm、Broadcom、Marvell、LG、Samsung、Huawei等)正積極的朝向此
新世代無線通訊IEEE 802.11標準來布局，若台灣在此領域有相關人員的支
持，在標準制定會議上可預期會有一席之地。除此之外，從會議中可看出，
若要使本身公司提出之技術被接受，除了技術本身要夠前瞻外，如何得到其
他公司的支持也是另外一個重點，因為能得到其他公司的支持才能將本身技
術打入標準規格內，提升公司之能見度。
34

IEEE 802 Meeting會議報告

Transcription

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