WI-FI 표준 기술 및 동향 Wi-Fi 시장 가치 •Wi-Fi 트래픽 전담율이 셀룰러의 2배 이상이며, 70%에 달함 Android smartphone data traffic of major markets (Canada,

WI-FI 표준 기술 및 동향

2014.04.24 TTA Wi-Fi 표준기술 교육 LG 전자, 차세대 통신 연구소

이욱봉 ([email protected])

• Market

• Standards

• Wi-Fi 응용 기술: Use cases

• 차세대 Wi-Fi

Agenda

Market

Wi-Fi 시장 가치

• Wi-Fi 칩셋 출하량이 하루 500만개임

Wi-Fi 시장 가치

• Wi-Fi 트래픽 전담율이 셀룰러의 2배 이상이며, 70%에 달함

Android smartphone data traffic of major markets (Canada, Germany, Japan, South Korea, UK, US)

2012. 8 2013. 4

source: Mobidia, ’13

2018년에 Wi-Fi는 20~50% 정도의 추가 용량 증대를 가져올

것임

Wi-Fi 시장 가치

New mobile data capacity gained from various techniques

source: Maravedis-Rethink operator survey

Wi-Fi 시장 가치

• Wi-Fi is all about Connectivity!!

Mobile PC CE

Auto-

motive

• 스마트폰 Wi-Fi 장착율 100%

• 스마트 홈 핵심 Connectivity 기술 Wi-Fi

• In-car 엔터테인먼트용 Wi-Fi

Wi-Fi is core of connectivity

Standards

Wi-Fi 표준

무선접속기술 (PHY, MAC)

용용 기술 (상위 layer, Application)

IEEE 802.11 표준화

WFA (Wi-Fi Alliance) 표준화

• IEEE란? – Institute of Electrical and Electronics Engineers 의 약자

– 160여개국 40만명 이상의 멤버. 50% 이상이 미국외에 거주.

– Professional association headquartered in New York City that is dedicated to advancing technological innovation and excellence

– 대표적인 표준화 기구: IEEE Standards Association (IEEE-SA).

– 다양한 분야에 연관된 표준을 다룸: power and energy, biomedical and healthcare, Information Technology (IT), telecommunications, transportation, nanotechnology, information assurance 등.

– 2012년 기준, 1400개 이상의 표준과 과제가 진행 중.

– 대표적인 IEEE 표준은 IEEE 802 LAN/MAN group of standards이며, IEEE 802.3 Ethernet 표준과 IEEE 802.11 Wireless Networking 표준이 대표적임.

IEEE/ IEEE 802.11 소개 (1/4)

• IEEE 802.11이란?

– IEEE 802.11은 흔히 무선랜, 와이파이(Wi-Fi)라고 부르는 좁은 지역(Local Area)을 위한 컴퓨터 무선 네트워크에 사용되는 기술로,

IEEE의 LAN/MAN 표준 위원회 (IEEE 802)의 11번째 워킹 그룹에서 개발된 표준 기술을 의미한다.

IEEE/ IEEE 802.11 소개 (2/4)

• IEEE 802.11 Working Group 소개

IEEE/ IEEE 802.11 소개 (3/4)

• IEEE LAN/MAN 표준 위원회 (IEEE 802)의 11번째 워킹

그룹에서 개발된 표준 기술


Type Group Description

WG WG11 The IEEE 802.11 Working Group

TG MC Maintenance – Revision “mc”

TG AC Very High Throughput (<6 GHz bands)

TG AF Operation in TV Whitespace bands

TG AH Operation in 900 MHz bands

TG AI Fast Initial Link Setup (FILS)

TG AJ China 60 GHz (China millimeter wave; including 45GHz)

TG AQ Pre-association Discovery (PAD)

TG AK General Link (bridging using 802.1 mechanisms across an 802.11 link)

SG HEW High Efficiency WLAN

SC WNG Wireless Next Generation

SC ARC Architecture

SC JTC1 ISO/IEC/JTC1/SC6 shadow committee

SC REG Regulatory

• IEEE 802.11 Revisions


802.11k

RRM

802.11r

Fast Roam

a 54 Mbps

5GHz

b

11 Mbps

2.4GHz

d

Intl roaming

802.11v

Network

Management

802.11s

Mesh

802.11u

WIEN

802.11y

Contention

Based

Protocol

802.11n

High

Throughput

(>100 Mbps)

802.11w

Management

Frame

Security

802.11z

TDLS

802.11p

WAVE

802.11

-1999

PHY

MAC

802.11

-2012

802.11

-2007

802.11aa

Video Transport

802.11ae

QoS Mgt Frames

802.11ah

<1GHz

802.11ac

VHT

6Gbps @ 5GHz

802.11ai

FILS

802.11ad

VHT

6Gbps @ 60GHz

802.11af

TV Whitespace

802.11

-2003

g

54 Mbps

2.4GHz

e

QoS

i

Security

h

DFS & TPC

j

JP bands

f

Inter AP

802.11ak

GlobalLink

802.11aj

40 & 60 GHz

802.11aq

Service Discovery

• Infrastructure mode

– An access point (AP) and multiple stations (STAs)

– Infrastructure Basic Service Set (BSS)

• Ad hoc mode

– Multiple stations (STAs), no AP

– Independent Basic Service Set (IBSS)

Wi-Fi 기초: Network Architecture Mode

• Distributed Coordination Function (DCF)

– Contention-based channel access

– Mandatory

• Point Coordination Function (PCF)

– Contention-free channel access

– Optional

• DCF only for most commercial 802.11 devices

– Contention-based channel access

Wi-Fi 기초: Coordination Functions

• Time-division-based packet-by-packet transmission

• Carrier Sense Multiple Access with Collision Avoidance

(CSMA/CA)

– Similar to IEEE 802.3 Ethernet CSMA/CD

• Binary Exponential Backoff

Wi-Fi 기초: MAC Architecture

• Hidden Terminal

• RTS/CTS exchange

Wi-Fi 기초: RTS/CTS

• OFDM – Orthogonal Frequency Division Multiplexing

• OFDM 장점 – High-speed 전송에 적합

– 무선 채널 (frequency-selective fading)에 강인함

– FFT/IFFT라는 모듈을 이용한 쉬운 구현

– 다중 직교 서브-캐리어 전송을 통한 주파수 효율 증가

Wi-Fi 기초: OFDM

• MIMO

– Multi Input Multi Output

– Multiple Antennas at both transmitter and receiver sides

– Each user’s signal suffers from interference other user’s signal if there is no

sig processing

• MIMO 장점

– 다중 스트림 전송을 통한 데이터 전송율 향상

– 다이버시티 전송을 통한 신호대 잡음비 향상

– 송/수신 전력 감소를 통한 배터리 효율 향상

– 네트워크 관점에서의 MIMO 전송을 통한 시스템 성능 향상

Wi-Fi 기초: MIMO

Sym 1 (+2)

Sym 1

Sym 2

Sym 2 (+1)Interference

• 802.11 standards operate in one of two frequency bands: – 2.4-GHz band (specifically, 2.4000 to 2.4835GHz)

– 5.0-GHz band (specifically, 5.150 to 5.825GHz)

• 2.4 GHz band: A total of 14 channels (11 channels - FCC in US) – 5MHz separation in center frequency of each channel

– Only three non-overlapping channels: Channels 1, 6, and 11

• 5-GHz band: 24 non-overlapping channels (in US)

Wi-Fi 기초: Channels

Wi-Fi 표준 진화 (1/2)

• 약 5년 마다 약 10배씩 전송 속도 증가

802.11g

802.11n

802.11ac

차세대 Wi-Fi

(High Efficiency WLAN)

‘00.09 ‘03.09

2008.09

2014.7

600Mbps

802.11ad

2008.12

2.4GHz

5GHz

60GHz

802.11a

‘97.09

54Mbps

1997 2003 2008 2014

6.9Gbps (11ac)

6.7Gbps (11ad)


• 비교

802.11a/g 802.11n 802.11ac 802.11ad

주파수 대역 5GHz (11a)

2.4GHz (11g) 2.4/5GHz 5GHz 60GHz

전송 방식 OFDM OFDM OFDM OFDM

안테나 기술 SISO MIMO

(Up to 4 streams)

MU-MIMO (Up to 8 streams)

Directional

antenna

채널 대역폭 20MHz 20/40MHz 20/40/80/160M

Hz 2.16GHz

최대 전송율 54Mbps 600Mbps 6.9Gbps 6.7Gbps


• 11ac vs. 11ad

802.11n 802.11ac 802.11ad

주파수 대역 2.4 GHz/5 GHz 5 GHz only 60 GHz only

채널 대역폭 20 MHZ/40 MHz 20 MHz/40 MHz/ 80 MHz/160 MHz

2.16 GHz

MIMO Up to 4 streams Up to 8 streams 1 stream

최대 전송율 600 Mbps 6.9 Gbps 6.7 Gbps

핵심 전송 기술 MIMO MU-MIMO Directional antenna


• 11af, 11ah, 11ai

802.11af 802.11ah 802.11ai

목적 TV 유휴 대역 (TV White

Space) 에서 무선랜 활용

900 MHz 비면허

대역에서의 무선랜 활용 빠른 무선랜 접속

주파수 대역

TV White Space 대역

(54~88MHz,

470~806MHz 등)

1GHz 이하에서 TVWS

대역을 제외한 대역

(902~928MHz 등)

MAC 표준 기술이므로,

대역에 무관함

채널 대역폭 5.5MHz와 그의 배수 1/2/4/8/16MHz 사용하는 PHY 표준

기술의 채널 대역폭

핵심 기술

지오 로케이션 데이터

베이스 기반 TV 유휴

대역 활용 기술

- 새로운 프리앰블

- 짧은 비콘 (beacon)

신호

- 계층적 TIM (Traffic

Indication MAP)

- 절전 모드

- 프루브 응답 (Probe

response) 필터링 기술

- 빠른 무선랜 접속을

위한 새로운 디스커버리

프레임

-보안 절차 간소화

Extended range

•Reach garage, backyard, basement, attic

•1MHz and 2MHz mandatory modes

Battery operated sensors

•No power amplifiers

Ultra-low power consumption

•Optimized for small packet sizes (few hundred bytes) •Multi-year battery

•Long sleep time

IP connectivity

Wi-Fi 무선 접속 응용 표준 – 11ah (1/3)

• Wi-Fi M2M (Machine-to-Machine) – 1 GHz 이하 주파수 밴드(e.g.,북미 902-928MHz)를 활용하여

1Km 이상의 커버리지 확대

• 응용 분야

– 스마트 홈 (1개의 AP로 집 전체를 커버)

– 다양한 M2M/IoT 기기를 위한 대용량, 저전력 통신 제공


• 특징 – Extended Range

– Low Power

– Rich data rates

– Scalable

– IP connectivity

– Outdoor support (larger delay/Doppler spreads)

• Data rates

• 11ah 스펙트럼 현황 (Sub 1GHz)


Wi-Fi 무선 접속 응용 표준 – 11ai (1/2)

• Fast Initial Link Set-up (FILS)

– 네트워크 & BSS 디스커버리

– 인증과 등록

– IP address configuration

– 기술 요구 조건

– 100ms 이내

– 1초 내에 100개 이상의 STA (station)에 대한 association 지원

– 기존 보안 성능 유지

Wi-Fi 무선 접속 응용 표준 – 11ai (2/2)

• 11ai는 사용자의 네트워크 연결 경험 향상 제공 – 빠른 무선랜 접속

– AP-to-AP handoff 성능 향상

– Probe storm 해결

– 제공 기술

– 프루브 응답 (Probe response) 필터링 기술

– 연결 시간 단축 위한 새로운 디스커버리 프레임

– 보안 절차 간소화

Wi-Fi 무선 접속 응용 표준 – 11af (1/2)

• TVWS (TV White Space) – TV 유휴 대역 (TV White Space) 에서 무선랜 활용

• 저 주파수 대역 이용으로 넓은 커버리지 서비스 가능

Traffic Offloading

Wi-Fi 무선 접속 응용 표준 – 11af (2/2)

• 지오 로케이션 데이터 베이스 기반 TV 유휴 대역 활용 기술

• 진행 상황

– 미국 : FCC NPRM 12-118 (600MHz 대역 repacking and auction) 진행

중 ( 2015년 완료예정)

– 국내 : 시범서비스 사업자 선정 및 시범서비스 실시 (2014.01)

Wi-Fi connectivity 진화

• Wi-Fi (2.4/5GHz)와 WiGig (60GHz) 기반 Tri-band connectivity

Wi-Fi 응용 기술: Use cases

• Wi-Fi Alliance

– Wi-Fi Alliance (WFA)는 WLAN의

국제화를 위해 1999년에 설립된

국제 비영리 민간단체 (NPO)임.

– 현재 550개 이상의 회원 사가 참여하고 있으며, 그 수는 계속 늘어나고 있음.

– 기본적으로 Wi-Fi라는 이름으로 나가는 device는 WFA를 통해서

certification받아야 함.

– Wi-Fi CERTIFIED n, Wi-Fi

CERTIFIED ac, Wi-Fi DirectTM,

MiracastTM 등은 certification

program 이름임.

– Web site: http://www.wi-fi.org/

Wi-Fi Alliance (WFA) 소개

Full

list

of

mem

ber

co

mp

an

ies

at

ww

w.w

i-fi

.org

http://www.wi-fi.org/




http://www.broadcom.com/

http://www.microsoft.com/

http://www.sony.com/

http://www.ti.com/sc/wirelessnetworking

http://www.juniper.net/

http://www.arubanetworks.com/index.php

http://www.lenovo.com/

Passpoint (Hotspot 2.0)

• 셀룰라 오프로딩을 위한 Wi-Fi 기술

• Hotspot 네트워크를 셀룰라 네트워크처럼 간단하게 접속하게 접속할 수 있게 해주고, Secure 하게 만들어줌

Miracast (Wi-Fi Display)

• Source 디바이스의 화면을 Sink 디바이스의 화면에 mirroring해주는 Wi-Fi 기술

• 쉬운 setup, configuration 방법과 시작, 조작, 멈춤 등의 기능을 제공

• AP없이 Wi-Fi 인증 디바이스 간에 연결하는 방법 (peer-to-peer 연결방식)을 제공하는 Wi-Fi 기술

Wi-Fi Direct (Wi-Fi P2P) Services (1/3)

• WFDS 지정 서비스: Send/Play/Display/Print/Enable

• Application Service Platform: (1) 타사 호환성 (2) 공통 플랫폼 (3) 3rd 파티 확장성

Wi-Fi Direct (Wi-Fi P2P) Services (1/3)

App

Send Play Print Display

Enable

Application Service Platform

Wi-Fi Direct

App App App App App

Service Service Service

WFDS Device

WFDS Device

Application level

interoperability

Standardized Common

Platform

…

…

Extensibility

for 3rd Party

Wi-Fi Direct (Wi-Fi P2P) Services(2/3)

SEND PLAY

DISPLAY PRINT

• Use cases

차세대 Wi-Fi

Motivation on Next Generation Wi-Fi

Mobile PC CE Auto-

motive

Mobile/CE vendors desires high quality Wi-Fi to satisfy user expectation2)

Operator desires cellular offload to lighten traffic explosion1)

Wi-Fi market is enlarging

by joining of mobile/CE vendors, operators, auto-motive

Motivation on Next Generation Wi-Fi

1990 1995 2000 2005 2010 2015 2020 202510

5

106

107

108

109

1010

1011

1012

1013

Data

Rate

Year

1Tbps@2020

802.11b

(11Mbps)

802.11

(2Mbps)

802.11n

(600Mbps)

802.11a/g

(54Mbps)

802.11ac

(6.9Gbps)

200Gbps@2017

Possible? 200Gbps will be target of next Wi-Fi?

• IEEE 802.11 스터디 그룹 (2013.5~)

• IEEE 802.11 태스크 그룹 (2014.5~)

• 목적 – 실제 간섭이 심한 환경에서의 성능 개선

– 실내, 실외 다양한 시나리오

– ‘Carrier Wi-Fi’ 요구 사항 반영

– 2.4 GHz and 5GHz bands

802.11 High Efficiency WLAN (HEW)

802.11a/g

(OFDM, 54Mbps)

802.11n

(MIMO, 600Mbps)

802.11ac

(MU-MIMO, 6.9Gbps) 차세대 Wi-Fi (High Efficiency WLAN)

’00.09 ’03.09 ’08.09 ’14.5 ~ (Study Group은 ‘13.5 시작)

• Usage Scenarios


• sd

Slide 45

Usage Model AP density STA density Management Propagation Traffic

[tentative]

1

high density of APs

and high density of

STAs per AP

a Stadium 12-20m ~50/AP Managed Outdoor/Indoor Mobile

b airport/train stations 15-20m <120/AP Managed Outdoor? Mobile

c exhibition hall 5-10m 100/AP Managed Indoor Mobile/Enterprise

d shopping malls ~High ~High Managed Indoor Mobile

e E-Education ~1/class? ~40-60/AP Managed Indoor Enterprise

f Multi-media Mesh backhaul 50-200m? 1-10/AP Managed Indoor/Outdoor? Enterprise

2 high density of STAs

– Indoor

a dense wireless office <50m 20-30/AP Managed Indoor Enterprise

b public transportation ? High Managed Indoor Mobile

c lecture hall < 200m High Managed Indoor Enterprise?

d Manufacturing Floor Automation 50m 250/AP Managed Indoor ?

3

high density of APs

(low/medium density

of STAs per AP) –

Indoor

a dense apartment building 10m 5/AP Unmanaged Indoor Home

b Community Wi-Fi

(20/channel) Low Unmanaged Indoor/outdoor Home + Mobile

4

high density of APs

and high density of

STAs per AP –

Outdoor

a Super dense urban Street 10-20m 100-200/AP Managed Outdoor Mobile

b Pico-cell street deployment 150-200m High Managed Outdoor Mobile

c Macro-cell street deploymen (High) (High) Managed Outdoor/Indoor

5

Throughput-

demanding

applications

a surgery/health care (similar to 2e

from 11ac)

low Low Managed Indoor

b production in stadium (similar to

1d-1e from 11ac)

Low 3/AP Managed Outdoor

c smart car 1 AP? 5/AP Managed Indoor ?

• 핵심 Scenarios


Slide 46

Public transportation

e-Education

Outdoor (Street)

Station

1. 체감 전송 속도 향상

• 기가급 체감속도

• 접속지연, 간섭 문제 해결

2. 실외 환경 지원

• 실외 신호 감쇄 극복

3. 사용자 이동성 지원

• Seamless 인증 및 연결

• AP간 핸드오버

Residential A

B

C

D

E

핵심 Scenarios Vision

• HEW will consider MAC and PHY technologies

– To make more efficient use of spectrum resources in scenarios with a

high density of STAs per BSS.

– To significantly increase spectral frequency reuse and manage

interference between neighboring overlapping BSS (OBSS) in scenarios

with a high density of both STAs and BSSs.

– To increase robustness in outdoor propagation environments and uplink

transmissions.

– To improve power efficiency per station

Technologies - Direction

• Spatial domain techniques, CCA control

• Fully utilize resources in frequency domain

Technologies – Discussed in HEW SG

Freq.

802.11a

802.11n

(40 MHz)

802.11ac

(80 MHz)

802.11ac

(160 MHz)

Freq.

802.11a

802.11n

(40 MHz)

802.11ac

(80 MHz)

OFDMA

Capable

STA

OFDMA

Capable

STA

OFDMA

Capable

STA

OFDMA

Capable

STA,

or

802.11ac

STA

(160 MHz)

Ch.1

Ch.2

Ch.3

Ch.4

Ch.5

Ch.6

Ch.7

Ch.8

Guard Band

Guard Band

Guard Band

UL MU-MIMO Interference

management

Dynamic Sensitivity Cont

rol (DSC)

DL MU-MIMO

(802.11ac)

Technologies – Discussed in HEW SG

Edge Throughput Enhancement

MAC Enhancements

MIMO/Beamforming

Multiplexing Schemes

Simultaneous Transmit and Receive

Overlapping BSS Handling

• HARQ

• Larger CP

• Basic Access Mechanism enhancements

• Dynamic Sensitivity Control

• Traffic Prioritization, QoE

• Multicast transmissions

• Massive MIMO, MIMO Precoding

• DL/UL MU-MIMO

• Beamforming for OBSS

• Beamforming for Interference Handling

• OFDMA, SDMA, OFDM-IDMA, FFR

• TD-uCSMA

• Channel Bonding

• Interference management, Antenna pattern

nulling

• Efficient resource utilization

• Control frame transmission reduction

• MAC/PHY mechanisms for enabling In-Band STR

• Enhancements for enabling out-Band STR

Technologies – Exemplary performance gain (1/2)

• OFDMA

– New approach I: Supporting additional contiguous bandwidth option

– New approach II: Supporting non-contiguous bandwidth

Channel (red color means busy) Resource utilization

CH1 CH2 CH3 CH4 probability Legacy Approach I. Approach II.

Case 1 p(1-p)2

Case 2 p(1-p)2

Case 3 p(1-p)2

Case 4 p2 (1-p)

Case 5 p2 (1-p)

CH 1 CH 2 CH 3 CH 4


• OFDMA

– Available bandwidth: Amount of resource that can be utilized in average sense

– Example in 160MHz,

99%

105%

83%

53%

54%

42%


• CCA control – improving spatial reuse more than 2 times

– Scenario 1, AWGN, 1 channel, 100% DL

• 일정

• May 2013

– Initial meeting

• July 2013

– Presentations

– SG Extension

• Sept 2013

– Presentations

• Nov 2013

– Presentations

– Initial PAR and 5C

– SG Extension


Slide 53

• Jan 2014

– Presentations

– Final version of PAR and 5C

– WG Approval

• March 2014

– Presentations

– EC Approval

• April 2014

– Nescom approval

• May 2014

– TG starts: 802.11ax

Slide 54

감사합니다.

이욱봉 ([email protected] )

mailto:[email protected]

LG전자

차세대통신연구소

최진수 선임연구원 ([email protected])

IEEE 802.11ah 표준기술 동향

mailto:[email protected]

IEEE 802.11ah – Goal and Usage Scenarios

- Scope and Target

- 11ah Use Cases

- Projected IEEE 802.11ah Timeline

IEEE 802.11ah – PHY

– Key PHY Features

– Functionalities

IEEE 802.11ah – MAC

– Key MAC Features

– Functionalities

2

Agenda

3

IEEE 802.11ah – Goal and Usage Scenarios

Scope and Target Scope and purpose

- This amendment defines enhancements to the IEEE 802.11 Medium Access Control (MAC) to support an Orthogonal Frequency Division Multiplexing (OFDM) Physical layer (PHY) operating in the license-exempt bands below 1 GHz, e.g., 868-868.6 MHz (Europe), 950 MHz -958 MHz (Japan), 314-316 MHz, 430-434 MHz, 470-510 MHz, and 779-787 MHz (China), 917 – 923.5 MHz (Korea) and 902-928 MHz (USA), and enhancements to the IEEE 802.11 Medium Access Control (MAC) to support this PHY

- Coexisting with the 802 PHYs currently operating in the respective band and provides mechanisms that enable coexistence with other systems in the bands including IEEE 802.15.4 and IEEE P802.15.4g

Companies involved in 802.11ah standard

- Broadcom, Intel, Qualcomm, Marvell, LGE, Huawei, ETRI, ZTE, Nokia, I2R, Samsung, etc

4

Scope and Target Target of the project

- The data rates defined in this amendment “optimize the rate vs. range performance” of the specific channelization in a given band

- This amendment also provides adds support for:

• transmission range up to 1 km

• data rates > 100 kbit/s

• fixed, outdoor, point to multi point applications

• while maintaining the 802.11 WLAN user experience for fixed, outdoor, point to multi point applications.

5

11ah Use Cases Use case category 1: Sensors and meters

- Environmental, industrial, healthcare & home/building sensors (indoor & outdoor)

• Extended range

• Battery operated sensors

6

11ah Use Cases Use case category 2: Backhaul sensor and meter data

- Backhaul aggregation of smart grid meter data

- Backhaul aggregation of industrial sensor data

7

11ah Use Cases Use case category 3: Extended range Wi-Fi

- Extended range Wi-Fi hotspots

- Extended range for cellular traffic offloading

8

Projected IEEE 802.11ah Timeline

9

1 3 5 7 9 11 1 3 5 7 9 11 1 3 5 7 9 11

‘13 ‘14 ‘15

TGB LB R-LB SB R-SB

SFD

D 0.1

D 1.0

SFD (Spec Framework Document)TGB (Task Group Ballot): Draft texting and review internally in TGLB (Letter ballot), R-LB (Recirculation LB)SB (Sponsor ballot), R-SB (Recirculation SB)

Letter ballot stage- Letter ballot for Draft 1.2 (Mar meeting)

- Going forward to generate Draft 2.0 in May meeting

CurrentEC&RevcomApproval

WiFi alliance proceeded formation meeting of 802.11ah extended range MTG (starting stage)

10

IEEE 802.11ah – PHY

Key PHY Feathers

Interoperable 1,2,4,8,16MHz bandwidth modes to support flexible deployment in global market– Each bandwidth mode (except 1MHz mode) has down-clocked structure by a

factor of 10 from 20,40,80,160MHz used in IEEE 802.11ac

– Bandwidth modes of ≥2MHz are implemented by fully-scalable structure

– 1MHz mode is a little bit differentiated from ≥2MHz modes but it can coexists with ≥2MHz bandwidth modes by the auto-detection rule

Fruitful data rate set for different link budget environments– 150Kbps to 340Mbps data rates

– Special MCS 1MHz mode with 2x repetition for extended range

11

Basically, 11ah PHY inherits the baseline design from 11ac/11n- Optimized for robust link and extended coverage in sub-1GHz band

Key PHY Feathers (cont’d)

BCC encoding (optional LDPC)– Most companies have implemented both encoding shcemes

Multiple antenna support– Support for SU/MU MIMO, Beamforming

– Unify preamble structures to support MIMO schemes

Travelling pilot for high Doppler environment - Support for 11ah outdoor scenario

- Travelling pilot position than using midamble

12

Basically, 11ah PHY inherits the baseline design from 11ac/11n- Optimized for robust link and extended coverage in sub-1GHz band

Channelization – Sub 1GHz Global Spectrum

13

CountryFrequency

(MHz)BW

# of available 1MHz Ch



US 902 – 928 26MHz 26 13 6

EU 863 – 868.6 5.6MHz 5 2 1

Japan915.9 -928.1

12.2MHz 11 0 0

Korea 917 – 923.5 6.5MHz 6 3 1

China 755 - 787 32MHz 32 4 2

Among all available channels, the new BSS should select an idle channel which can help keep maximum number of idle (available) wider bandwidth channels after it is selected

11ah OFDM Parameters

14

Same with 11ac

1/10 spacingcompared to 11ac

10 times durationcompared to 11ac

Down-clocked from 20,40,80,160MHzby a factor of 10

Interoperable Bandwidth Modes - Preambles

Short preamble structure for ≥2MHz

– Can be used for SU transmission

Long preamble structure for ≥2MHz

– Can be used for MU and SUBF

15


Preamble structure for 1MHz

– Can be used for 1MHz SU transmission

16


Auto-detection between 1MHz and 2MHz and between >=2MHz short and long preambles

17

Data Rate Set

18

BW in MHzRange of data rates supported for 1ss

Range of data rates supported for 2ss

1 150 kbps to 4Mbps 600 kbps to 8 Mbps

2 650 kbps to 7.8 Mbps * 1.3 Mbps to 15.6 Mbps *

4 1.35 Mbps to 18 Mbps 2.7 Mbps to 36 Mbps



*: MCS9 not allowed due to non-integer number of N dbps required to fill OFDM symbol

MCS Table

19

MCS Index Mode Code Rate

Data Rates for 1MHz BW(kbps)

Data Rates for 2MHz BW(kbps)

8us GI 4us GI 8us GI 4us GI

0 BPSK 1/2 300 333.3 650 722.2

1 QPSK 1/2 600 666.7 1300 1444.4

2 QPSK 3/4 900 1000 1950 2166.7

3 16-QAM 1/2 1200 1333.3 2600 2888.9

4 16-QAM 3/4 1800 2000 3900 4333.3

5 64-QAM 2/3 2400 2666.7 5200 5777.8

6 64-QAM 3/4 2700 3000 5850 6500.0

7 64-QAM 5/6 3000 3333.3 6500 7222.2

8 256-QAM 3/4 3600 4000 7800 8666.7

9 256-QAM 5/6 4000 4444 8666.7 9629.6

10 (1MHz BW only)

BPSK 1/4 150 166.7 N/A(Not supported)

N/A(Not supported)

To support extended range in 1MHz mode (specific in 11ah)

Physical Processing for Regular MCSs

20

In case of MCS10 (MCS0-rep2), no encoder/stream parser, STBC, CSD

Traveling Pilot

Travelling pilot is an optional feature used to improve channel estimation under high Doppler scenarios

– Compared to fixed pilot pattern in existing 802.11, it shifts pilot position across symbols

– Need capability negotiation (not used for all devices)

21

14 OFDM symbols have different pilot position in frequency

Travelling pilot positions for NSTS=1, 2MHz S1G PPDU

2MHz mode has 4 pilot subcarriers per OFDM symbol

22

IEEE 802.11ah – MAC

Key MAC Feathers

Short frames to reduce active Tx/Rx time – Short Control/management frames: use an NDP type with MAC info in SIG field

- Short MAC header: reduce unnecessary information field

- Short beacon frame (and compressed TIM): reduce beacon decoding time

- Short probe request/response

Support for larger number of associations from devices – New hierarchical TIM structure and encoding: minimize TIM overhead

– Multiple TIM and page segments: minimize power consumption and channel contending from many devices

23

With baseline design from 11ac/11n, 11ah MAC further optimizes the power saving and contention resolution features

Key MAC Feathers (cont’d)

Pseudo-scheduling and grouping traffics to support large number of devices in network and reduce contention time – Target wakeup times (TWT) for STAs agreed with AP

– Periods of time where contention is restricted to group of STAs (RAW)

– Speed frame exchange for quick UL/DL transaction

Increase standby time – Improved polling operation: Non-TIM STA operation, rescheduling of doze/wake

time

– Extend listen and MAX BSS idle periods to allow STAs sleep for hours/days

24

With baseline design from 11ac/11n, 11ah MAC further optimizes the power saving and contention resolution features

Short frames Short control/management frames

– Totally 8 NDP type MAC frames

• Control frames: NDP CTS, NDP PS-Poll, NDP ACK, NDP Modified ACK, NDP Block ACK, NDP Beamforming Report Poll, NDP Paging

• Management frame: NDP probe request

– SIG field contains specific information for each NDP frame

Short MAC header

– The concept of storing constant MAC header information

25

AID BSSID

BSSID/RA AID

Different information from normal frames

Short frames Short beacon frame

– Some fields have compressed values to minimize beacon size

Short probe request/response

– Very similar form from short beacon frame (basically similar purpose)

– Some optional fields which are conveyed eventually

26

Hierarchical TIM Structure

27

Compared to existing 802.11 TIM bitmap which addresses the paged AIDs sequentially, the TIM overhead in 11ah is significantly reduced by the hierarchical TIM approach

TIM->Pages->Blocks->Subblocks->STAs

TIM and Page Segmentation

28

In a BSS with large amount of associated STA, it is not viable to indicate downlink buffered data for all STAs in a Page in the TIM element

– An AP can fragment the TIM element into equal size of TIM segments containing Page Segment with a subset of STA AIDs

STAs’ AIDs are included incertain page segment based on its traffic/service pattern, battery life, and so on

Target Wake Time (TWT)

29

Target Wake Time (TWT) allows an AP to manage the activity in the BSS to minimize contention and to reduce the required amount of time that a STA utilizing a power management mode needs to be awake to exchange frames with other STAs

– Assignment of specific times for a participating STA (TWT STA) to wake to access the medium

– TWT STAs need to communicate their wake requirements to APs and APs need to devise a schedule and deliver TWT values to STAs

– This mechanism can be effective specifically in 11ah that many devices are operated in battery limited environment

Restricted Access Window (RAW) Operation

The restricted channel access control mechanism manages access to the WM to avoid simultaneous transmissions from a large number of STAs hidden from each other and enables fair channel access among the STAs

– An AP may allocate a medium access interval called RAW (restricted access window) for a group of STAs within a beacon interval

– Only the STAs in the group are allowed to access the WM in the RAW

– Assigning restricted uplink channel access windows to different groups of STA increases fairness

30

To avoid hidden node problem,slot duration covers PS-Poll+Data+ACK transmission time

Speed Frame (SF) Exchange Operation

31

Speed frame (SF) exchange allows an AP and non-AP STA to exchange a sequence of uplink and downlink PPDUs separated by SIFS - This operation combines both uplink and downlink channel access into a continuous

frame exchange sequence between a pair of STAs

- The objective of this operation is to minimize the number of contention-based channel accesses, improve channel efficiency by reducing the number of frame exchanges, and reduce STA power consumption by shortening Awake times

Without PS-Poll/ACK response, DL & UL data can be exchanged based on MD and ACK indication field

SIFS

Improved Polling Operation

Non-TIM STA operation

– Non-TIM STA is a STA who don’t have to listen TIM beacon and keep sleep status before polling (very low power operated device)

– To mitigate burden in AP buffer management, this STA shall transmit at least one PS-Poll or trigger frame during its own listen interval

Resource protection for Non-TIM STA

– AP may indicate to TIM STAs a Restricted Access Window (RAW) information during which no TIM STA is allowed to contend

Rescheduling of wake/doze cycle

– Upon receiving the PS-Poll/trigger frame, an AP may respond with a control frame that includes a timer to indicate the wakeup timer value

– The STA may re-synchronize to the beacon with the help of the wakeup timer value

32

Improved Polling Operation (cont’d)

Active polling

– Upon waking up and without listening for a beacon, an active polling STA may solicit BSS change sequence and/or current timestamp information from an AP by sending a polling message (PS-Poll)

TIM operation mode change and listen interval update

– When a STA changes TIM operation mode from TIM mode to Non-TIM mode and updates the listen interval that is different from the value established in the association request frame, the STA can request the listen interval change to an AP

– As the response to the corresponding request, the AP may responds to the STA

33

Extension of Power Saving Intervals

Unified Scaling Factor (SF) can extend the power saving intervals

– BSS Max idle period, Listen interval, WNM-Sleep interval

– To support sleep duration during more than hours/days in 11ah power limited sensor devices

34

Two MSBsScaling factor

(SF)

00 1

01 10

10 1000

11 10000

All BSS MAX idle period, listen interval, WNM-Sleep interval have this scaling parameter with 2 bit and extend intervals by unified scaling manner

• E.g. SF=01, interval increase by a factor of 10

Indicates actual duration with 14 bits

802.11ah standard defines both PHY and MAC functionalities– PHY features

• Support interoperable bandwidth modes and additional 1MHz bandwidth mode to support extended Wi-Fi range

• Various data rate support which is good at different link budget conditions

• BCC encoding with optional LDPC implementation

• Maintain multiple antenna support

• Support travelling pilot for 11ah outdoor scenario

– MAC features• Support short frames to reduce power consumption and medium overhead

• Hierarchical TIM structure and TIM/paging segmentation to support large number of devices

• Pseudo-scheduling and grouping to reduce contention time

• Non-TIM STA operation and enhanced polling operation support

802.11ah will be a candidate and attractive system for vendors and operators in sensor oriented network and outdoor environment with enhanced coverage

Summary

35

Thank you!

TTA 표준기술 세미나, 2014.04.25

New Things New Power

발표 순서

• Why WiFi?

– Free

– Forecasting

– Small Cell

– WBA

– Interference

• WiFi Device

– GiGa WiFi

– TVWS WiFi

• WiFi Application

– HOME

– IOT

Why WiFi ?

Why WiFi ?

• 표준기술

• 충분히 발달된 제품

• 광대역 수용

• 유선비용 절감

• 전송량 대비 경제성

• 비면허 대역 이용

• 2015년 약 22억 개 WiFi 단말이 사용 될 것으로 예측

• 무선 멀티미디어, 오피스, M2M 등 급격한 무선 트패픽의 증가

Why WiFi? – Free !

주민센터, 복지시설, 전통시장 등 국민들이

자주 이용하는 공공장소

2014.3 ~ 4

Why WiFi? – Free !

뉴욕

샌프란시스코

LA

Why WiFi ? – Free !

Why WiFi ? – Forecasting

• WiFi 연결 가능한 스마프폰 증가(14억 개, 2013년, ABI)

• 3년간 Mobile Internet Traffic 50배 증가 (AT&T)

Why WiFi ? – Forecasting

Market Prediction of WLAN Enterprise Networks

Why WiFi ? - Forecasting

WLAN AP Shipments- Worldwide 2009-2016

Why WiFi – Easy & Quick

IEEE 802.11 표준화 현황

Why WiFi ? – Small Cell

출처 : Wi-Fi and Heterogeneous networks, Fabio Rodriguez, Erisson

• Mobile Data Traffic 증가

• Mobile Broadband 사용자 증가

• 도심의 밀집도 증가

• 스마트 기기 증가에 따른 WiFi 사용기기 증가

지역 별 불 균일 한 Data Rate ?


기지국 성능개선? 고밀집화? 기지국 추가 설치? One Network

Heterogeneous Network




• 안전한 자동 Seamless 접속을 통

한 사용자 편리

• 네트워크 지식 기반의 Always

Best Connect와 최적 리소스 제

공

• 기존 시스템과 Plug & Play 사용

Why WiFi ? – WBA(Wireless Broadband Alliance)

MNO가 기대하는 새로운 Mobile data 수용기술

Public WiFi에 대한 태도의 변화

2013년 10월 WBA에서 Maravedis-Rethink을 통해 Survey 수행

*출처 : Wireless Broadband Alliance Industry Report 2013: Global Trends in Public Wi-Fi

Why WiFi ? – WBA(Wireless Broadband Alliance)

• Public Wi-Fi ecosystem 개발

– The device ecosystem

• Passpoint™ 지원 단말

• 2.4GHz 및 5GHz 대역 지원 단말(IEEE 802.11n & 11ac)

• 멀티 모드 디바이스 플랫폼(퀄컴 등)

– Seamless interoperability

• NGH (Next Generation Hotspot – WBA)

• Hotspot 2.0/Passpoint™ (WFA)

• ANDSF (3GPP)

– Roaming progress

• WBA ICP (Interoperability Compliance Program)

– Standards를 통한 ecosystem 활성화

• Purple Wi-Fi 및 Wavespot 과 같은 Social media 서비스 개발

Why WiFi ? WBA(Wireless Broadband Alliance)

• 스펙트럼 간섭문제

– 장소 독점 방식 활용

• 쇼핑몰, 공항, 경기장 등 특정 독점계약을 통한 공공 WiFi 서비스 제공

– 중립 호스트로 공용 WiFi 활용

• 공용 WiFi 공유를 통한 다양한 사용자 서비스 수용

– 간섭완화 기술

• Dynamic re-planning radio

• Beam Forming


• 광대역 5GHz대역 및 새로운 스펙트럼 활용

– 5GHz대역의 New 대역 활용 연구

– 11ac의 60GHz, 11ah 900MHz, 11af TVWS 등


Carrier grade WiFi Hotspot 수 예상 WiFi Hotspot 유형 별 예상


사업자의 hotspot 소유 방식 예측 12개월후 트랙픽 요구가 가장 크게 요구될 사이트

Why WiFi ?

But, WiFi ? – Interference

ISM 대역 전파간섭

• 무선랜과 무선랜간 간섭은 동일채널을 사용할 경우 무선랜간 30m 이내에 서는 정상속도 대비 50~80%

정도의 속도가 저하

• 동일채널보다는 인접한 채널에서 더 심각한 속도저하(60~80%)가 발생 되므로 무선랜이 전파간섭

없이 사용하려면 최소 40m 이상 이격하고 5채널 이상 이격하여야 전파간섭에 의한 속도저하 없이

사용

출처 : KCA, 동향과 전망 : 방송·통신·전파 통권 제67호



• KTX 서울역

– AP 351개 , STA 1101개 ( 주로 사업자 AP가 많음)


• 대부분 AP는 1,5,9,13ch 사용 권고를 따르고 있음


• COEX WiFi 간섭 현황 (Wi-Fi Interference Measurement in Korea , doc.: IEEE11-13/0556r1)

– AP 227개, STA 917개 ( KT, SKT, LGU+ 및 120개 개인용 AP)


• 사업자 AP의 경우 1,5,9,13ch 권고에 의한 사용을 하나 개인 AP는 그렇

지 못함


• COEX의 경우 기존 WiFi(11b/g) 및 개인 AP가 많어 전 채널에 WiFi 간

섭이 존재하나, KTX 서울역은 비교적 1,5,9,13ch 사용을 통해 비교적 안

정적 Throughput을 제공 함

But, WiFi ? – 11ac

출처 : The Wi-Fi Evolution An integral part of the wireless landscape, Qualcomm

But, WiFi ? – 11ac

But, WiFi ? – 11ac MU-MIMO

But WiFi ? –Best access

WiFi Device

GiGA WiFi

GiGa WiFi - GST

GiGa WiFi

GiGa WiFi Benchmark

802.11ac Routers Compared: Apple, Belkin, Netgear , Linksys http://www.tekrevue.com/802-11ac-routers-compared-apple-belkin-netgear-linksys/

품명 제조사 가격대(Amazon)

AirPort Extreme Apple $184

R6300 Netgear $141

EA650 Linksys $145

AC1200 Belikin $100

GiGa WiFi Benchmark

TVWS WiFi Device – 영국 Neul

• End to end latency : 100ms 이하

• 가입자 장치 수용 능력 : 광대역 서비스 32개,

일반 M2M 서비스 256개, 협대역 M2M : 10만개

• 채널 대역폭 : 6MHz/8MHz 지원

∘ 총 전송용량 : 16Mbps

∘ 전송 출력 : 30dBm 이하

• 4W EIRP 지원(안테나 이득 포함)

∘ 수신 감도 : -85dBm ~ -128dBm

∘ 통신 인터페이스 : 10/100 Base Ethernet

TVWS WiFi Device – 미국 Carlson Wireless

TVWS WiFi Device – 미국 KTS Wireless

TVWS WiFi Device – 일본 NICT

TVWS WiFi - WSA(White Space Alliance)

WSA(White Space Alliance)는 White Space대역을 통한 광대역 기능을 제공하기 위해 표준 기

반의 제품 및 서비스의 개발, 배포 및 사용을 촉진과, WSA 회원사들은 상호 간 필요한 정보 및

협력을 통해 성공을 얻을 수 있도록 상호 운용성, 적합성 및 적합성 테스트을 수행하여 시장을 활

성화 목적을 두고 있으며,IEEE, 3GPP 및 IETF 표준의 사용을 촉진

WiFi – Multi Radio MIMO AP

Multi-array

MIMO 안테나

Multi-port Beam Former

+ Wi-Fi Core & RF Tranceiver

Network

Processor

WiFi Application

WiFi Application - Home


출처 : The Home of the Future: Intelligent and Connected, QUALCOMM




WiFi Application - IoT




WiFi Demand

Documents

WI-FI 표준 기술 및 동향 Wi-Fi 시장 가치 •Wi-Fi 트래픽 전담율이 셀룰러의 2배 이상이며, 70%에 달함 Android smartphone data traffic of major markets (Canada,