Transcript HomePlug Introduction

HomePlug AV Technical Overview
ISPLC 2006 – Orlando, FL
March 28, 2006
Larry Yonge
HomePlug AV TWG Chair
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
Copyright © 2005, HomePlug Inc
System Architecture
Higher Layer Entity (HLE)
Control SAP
Data SAP
HomePlug
AV Modem
H1
Interface
Convergence (CL)
Central
Coordinator
(CCo)
Connection
Manager
(CM)
M1
Interface
Media Access Control (MAC)
PHY
Interface
Physical (PHY)
Coupler
P1
Interface
Powerline
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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
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PHY Spectrum - 917 channels from 2-28 MHz


Tone Mask defined for North America
Amplitude Map enables additional nulls while maintaining
interoperability
Power Spectral Density Vs
Frequency
-50
-55
-60
Normalized Power
-65
-70
Nulls created simply through
configuration. Spectral nulls
required to avoid interference
with amateur bands. Different
rules in different countries
-75
-80
-85
-90
-95
0.5
1
1.5
Frequency [MHz]
2
2.5
3
7
x 10
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PHY Channel
Frequency
Selective
Channel
SNR Vs Freq.
Time Selective
Channel
40
SNR (dB)
30
20
10
0
3
8
13
18
23
28
Frequency (MHz)
 Frequency selective channel is unique for each
connection
 Time varying noise and impulse response is common
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PHY Encoding
MPDU
MPDU
Data In
PPDU
Frame
Control
PB
m
PB
m+1
PB
m+2
PB
m+3
PB
m+4
PB
m+5
PB
m+6
Scrambler
Turbo FEC
Encoding
Channel
Interleaving
IFFT
Cyclic
Extension
Window &
Overlap
Preamble
GI
51.2
18.3
SOF
FC
42
GI
7.6
D1
Mapper
PPDU
Signal Out
GI
42
QAM
Symbols
Out
7.6
D2
42
GI
var
D3
...
42
PAYLOAD
Copyright © 2005, HomePlug Inc
PHY Performance Test – 10 Homes
 Typical PHY data rates
– 70-100Mbps
 80% of outlet pairs
– 55 Mbps or better
 95% of outlet pairs
– 35 Mbps or better
 98% of outlet pairs
– 27 Mbps or better
 ~90% MAC efficiency for HDTV
Copyright © 2005, HomePlug Inc
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)
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MAC Encapsulation
MDSU
(from Host)
MAC Frame
(+6 bytes)
MAC Frame
Queue
DA SA
VLAN Length
Tag /Type
MAC Frame
Header
...
Segments
(512 bytes)
Payload
CRC
MSDU
MAC FRAME
n+1
MAC FRAME
n+1
MAC FRAME
n+2
...
SEG SEG SEG SEG SEG SEG SEG
m+1 m+2 m+3 m+4 m+5 m+6
m
AES Encryption
PHY Block
(+8 bytes)
MPDU
(to PHY)
PB ENC
CRC
HDR SEG
SOF
FC
PB
m
PB
m+1
PB
m+2
PB
m+3
PB
m+4
PB
m+5
PB
m+6
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MPDU Bursting
MPDUCnt = 2
MPDUCnt = 1
MPDUCnt = 0
Failed
Segments
Failed
Segments
SOF
Payload
SOF
Payload
SOF
Payload
SACK
Bit Map of
Bad Segments

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
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Beacon Period
AC Line Cycle
50/60 Hz
Line Cycle
Phase Sync
Beacon Period
(33.3 / 40 msec.)
Beacon
Region
CSMA
Region
Contention Free
(TDMA) Region
Beacon Period
(33.3 / 40 msec.)
Beacon
Region
CSMA
Region
Contention Free
(TDMA) Region
 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
Copyright © 2005, HomePlug Inc
Channel Adaptation
AC Line Cycle
50/60 Hz
T1
T2
T3
T1
T2
T3 T1
T2
T3
T1
T2
T3 T1
Beacon Period
(33.3 / 40 msec.)

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
Copyright © 2005, HomePlug Inc
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
Copyright © 2005, HomePlug Inc
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
Copyright © 2005, HomePlug Inc
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
Copyright © 2005, HomePlug Inc
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
Copyright © 2005, HomePlug Inc
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
Copyright © 2005, HomePlug Inc