homeplug av technical overview isplc 2006 – orlando, fl march 28, 2006 larry yonge homeplug av twg...

HomePlug AV Technical Overview

ISPLC 2006 – Orlando, FLMarch 28, 2006

Larry Yonge

HomePlug AV TWG Chair

Copyright © 2005, HomePlug Inc

HomePlug AV Marketing Requirements

Focus segment – In-home connectivity– Consumer Electronics (STB, HDTV, DVD, Audio)

Focus applications – Video and Audio distribution– Voice and Data

Performance Requirements– >100 Mbps class, whole home coverage for high quality streaming media

• Reliable, secure delivery with low latency and jitter– Efficient use of available system capacity, with graceful degradation– Acceptable for encrypted, copy protected content with DRM

Coexistence– HP 1.0– Easy bridging to other networking technologies

Coverage– At least 98% of outlet pairs must support a single 24Mbps HDTV stream– At least 90% of outlet pairs must support two simultaneous 24Mbps HDTV

streams Competitive cost


System Architecture

Convergence (CL)

Media Access Control (MAC)

Physical (PHY)

Connection Manager

(CM)

Higher Layer Entity (HLE)

CentralCoordinator

(CCo)

H1Interface

M1Interface

PHYInterface

P1Interface

Powerline

HomePlugAV Modem

Control SAP Data SAP

Coupler


PHY Highlights

Windowed OFDM– Spectral notching for preamble, frame control and payload

– 917 carriers (excluding Amateur bands)

Bit-loaded modulation: BPSK to 1024QAM– Optimum adaptation for each connection

Turbo FEC for frame control, beacon, payload– 16, 136 and 520 byte block sizes respectively

– Near capacity performance (1/2 dB from Shannon Capacity)

Channel interleaver for impulse noise and other PL impairments Diversity coding for reliable frame control, beacon and ROBO HP1.0 coexistence mode uses 1.0 frame control

– AV preamble can be detected by 1.0 devices

200 Mbps PHY channel rate – 150 Mbps PHY information rate


PHY Spectrum - 917 channels from 2-28 MHz Tone Mask defined for North America Amplitude Map enables additional nulls while maintaining

interoperability

0.5 1 1.5 2 2.5 3

x 107

-95

-90

-85

-80

-75

-70

-65

-60

-55

-50

Frequency [MHz]

Norm

aliz

ed P

ow

er

Power Spectral Density Vs Frequency

Nulls created simply through configuration. Spectral nulls

required to avoid interference with amateur bands. Different rules in

different countries


PHY Channel

Frequency selective channel is unique for each connection

Time varying noise and impulse response is common

SNR Vs Freq.

0

10

20

30

40

3 8 13 18 23 28

Frequency (MHz)

SNR

(dB

)

Frequency Selective Channel Time

Selective Channel


PHY Encoding

PBm

PBm+1

PBm+2

PBm+3

PBm+4

PBm+5

PBm+6

FrameControlMPDU

Preamble FC

51.2

GI

4218.3

D1GI

427.6

D2GI

427.6

D3GI

42var

Turbo FEC Encoding

Channel Interleaving

Mapper

IFFTCyclic

ExtensionWindow & Overlap

Scrambler

PPDU

MPDU Data In

PPDU Signal Out

QAM Symbols Out

PAYLOADSOF

...


PHY Performance Test – 10 Homes

Typical PHY data rates– 70-100Mbps

80% of outlet pairs– 55 Mbps or better



~90% MAC efficiency for HDTV


MAC Highlights

Network managed by a Central Coordinator (CCo) Three access methods within a network:

– Beacon: Non-contention, CCo transmits Beacon in dedicated slot – CSMA: Contention-based, exchange of priority-based user data

and management messages, shared with HP 1.0– Contention-free: Only designated station transmits. QoS guarantee

Beacon Period is divided into “Regions”– Schedules specified in Beacons– Different allocations are further specified in some Regions

Beacon Period synchronous with AC line cycle Allocations: persistent, or non-persistent (valid for

current Beacon Period only) Neighbor network coordination

– Sharing channel with other AV networks (MDUs)


MAC Encapsulation

Payload

MSDUMAC Frame

Header

SA

MAC FRAME n+2

MAC FRAME n+1

CRC

SEGm

SEGm+1

SEGm+2

Length/Type

DAMDSU(from Host)

MAC Frame(+6 bytes)

MAC FrameQueue

Segments(512 bytes)

MAC FRAME n+1

PBm

PBm+1

PBm+2

ENCSEG

PBHDR

CRC

SEGm+3

SEGm+4

SEGm+5

SEGm+6

PBm+3

PBm+4

PBm+5

PBm+6

AES Encryption

SOFFC

MPDU(to PHY)

PHY Block(+8 bytes)

......

VLANTag


MPDU Bursting

Many PHY Blocks (or segments) are typically sent in a single MPDU

– PHY blocks are individually Turbo FEC encoded– PHY Blocks are selectively acknowledged (SACK)– Provides efficient retry transmission over the noisy powerline medium

More than one MSDUs may be sent in a burst for efficiency

SOF SACKPayload SOF Payload

Bit Map ofBad Segments

SOF Payload

MPDUCnt = 2 MPDUCnt = 1 MPDUCnt = 0FailedSegments

FailedSegments


Beacon Period

Beacon period synchronized to AC line cycle– Provides timing for synchronized channel adaptation

• different bit loading for different phases on the AC line cycle– Provides stable QoS for TDMA allocations

BeaconRegion

CSMARegion

Contention Free(TDMA) Region

Beacon Period(33.3 / 40 msec.)

BeaconRegion

CSMARegion

Contention Free(TDMA) Region


AC Line Cycle50/60 Hz

Line CyclePhase Sync


Channel Adaptation

Receiver responsible for determining Tone Map intervals and up to 6 Tone Maps per transmitter

– Stations exchange SOUND PPDUs so the receiver can determine optimal tone maps (e.g., modulation per tone, code rate and cyclic prefix length)

– Stations continuously monitor data PPDUs (SNR estimate per carrier, PB error rate, etc.) to update tone maps

– Different tone maps may be used in different intervals of the AC line cycle


AC Line Cycle50/60 Hz

T1 T1T1T2 T2T3 T3T1 T1T2 T3 T2 T3


Central Coordinator

Beacons transmission – AC line cycle sync, network clock, & schedule

Association, authentication & security– Admit new stations into network

Admission control and bandwidth management– Determine schedules that meets QoS requirements

– Persistent allocation provides coarse-scale allocation

– Real-time adjustment made based on stations’ queue depth

Neighboring network coordination– Coordinate sharing of BW between neighbor CCos


Quality of Service (QoS)

Connections– Parameter Based QoS (TDMA) – Priority Based QoS (CSMA)

Higher Layer Entities (HLEs)– Connection Specification (CSPEC) and Control– QoS Management and Control

Connection Manager (CM)– Stations exchange QoS requirements (CSPEC) and set up a connection– CSPEC contains min./avg./max. data rate, delay bound, etc.– If contention-free allocation is needed, stations then send BW request to

CCo CCo

– Admission Control, Bandwidth Management and Scheduling Convergence Layer (CL)

– Packet classification based on CSPEC– Automatic connection service – create CSPEC– QoS Monitoring– Smoothing & Jitter Control


Neighbor Networks

One Physical Network & Many Logical Networks

CCo maintains an Interfering Network List (INL): contains networks that it interferes– A network coordinates with networks in its INL (i.e., no

chaining effect) to share the channel– CSMA Region is shared

– TDMA Regions are reserved for each network in the ILN• Reserved Regions may be reused by networks not in the ILN

Synchronization– CCo using the first Beacon Slot synchronizes to the AC

line cycle; all other CCos synchronizes to it


Security

Encryption is based on 128-bit AES in Cipher Block Chaining (CBC) mode

Data Protection (Privacy)– NEK: Payload encrypted with a rotating Network Encryption

Key– Tone Maps

Authentication: Gaining Network Access– NMK: Network Membership Key defines a logical network

and is used to distribute the NEK Authorizing a New Station

– Direct entry of NMK, requires a user interface– DAK: Encryption with Device Access Key– “Easy Connect” push button mechanism (less secure)

Supports HLE protocols such as 802.1x


Summary

HomePlug AV meets the market requirements for in-home networking– Physical Layer designed for robust, near capacity operation for the

powerline channel– MAC layer provides near optimum use of the PHY– QoS guarantees are provided for video, audio and voice– AV Specification provides implementation flexibility for innovation– Experience and product maturity will bring further performance

improvements Additional information about HomePlug technologies is

available on the HomePlug web site:– www.homeplug.org

homeplug av technical overview isplc 2006 – orlando, fl march 28, 2006 larry yonge homeplug av twg...

Documents

hdtv slide

mbps phy channel rate

mbps class

mac encapsulation slide

outlet pairs

system architecture

phy spectrum

av networks mdus slide