Transcript G3 PLC Overview

G3 PLC Overview
SPEAKER : SHIH-CHI HUANG
ADVISOR : DR. KAI-WEI KE
2014/04/07
Outline

PLC Background

G3 PLC Aims

G3 PLC Communication Profile


Physical Layer

MAC Layer

Network and Transport Layer

Application Layer
Conclusion
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PLC Background

電力線通訊是透過一般的電源插座當作網路連接阜，使
用電力線當作訊號傳輸的媒介，電力線通訊一般簡稱為
PLC(Power Line Communication)。
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PLC Technology

傳送端利用正交分頻多工(OFDM)技術將用戶資料加以
編碼與調變，然後在電力線上進行資料傳輸，

在接收端首先經過電力線耦合器及高頻濾波將調變信號
濾出，並經解碼與解調變之後，就可得到原來通訊信號。
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PLC Networks System
主要可分為兩大部分

Access BPL
(Access PLC)

In-House BPL
(In-House PLC )
PLC Category
根據頻寬的不同又可分為

超窄頻電力線通訊(Ultra Narrowband PLC)，超窄頻的頻
率範圍為 0.3 kHz 至 3 kHz

窄頻電力線通訊(Narrowband PLC)，窄頻的頻率範圍為
3 kHz 至 500 kHz

寬頻電力線通訊(Broadband PLC)，寬頻的頻率範圍為
1.8 MHz 至 250 MHz
窄頻電力線通訊的傳輸速度小於1Mbps，是用於長距離的
傳輸
寬頻電力線通訊的傳輸速度大於1Mbps，是用於短距離的
高速傳輸。
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Compare PRIME with G3
PRIME 推出
G3-PLC 漸漸成為
PLC 標準
一群企業紛紛使
全球窄頻電力線通
只支援 IPv4
用 G3-PLC 標準
訊的主流技術標準
G3 推出
PRIME 開始
PLC 標準
支援 IPv6
支援 IPv4
and IPv6
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G3 PLC PROFILE SPECIFICATION
G3 PLC Aims

Robustness : 通訊功能適合在極其嘈雜的環境下工作，如
低壓電力線、中壓電力線的長距離通訊，尤其支援 MVLV 變壓器間的通訊。

Performance : 雙向數位通訊，傳輸速率最高為300Kbps。

Simplicity : 易於執行、安裝(即插即用)、操作和維修。

Flexibility : 相容不同的應用和網路拓撲結構。

Security : AES-128 密碼引擎確保環境安全。

Compatibility : 相容於已經存在的系統。

Scalability : 支援 IPv6，可用於新的網際網路能源管理系
統和應用。
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G3 PLC Communication Profile
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Physical Layer
Two functional blocks :

The Physical processing block (PHY)
in charge of emission and reception
over the PLC medium

The PHY Management Entity (PLME)
responsible for managing the PHY
layer. It relies in particular on the PHY
Information Base (PHY PIB).
Physical Layer (Cont.)
The Physical Layer Management Entity (PLME) comprises the
following functions :

Carrier detection : This is one of the important elements of
the CSMA/CA procedure.

Phase detection : It allows identification of the phase on
which the meter transmits.

Management of the PHY PIB Information Base
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MAC Layer
Two functional blocks :

The MAC Common Part Sublayer
(MCPS) responsible for communication
with the neighbouring nodes

The MAC Layer Management Entity
(MLME) responsible for management of
the MAC sublayer. It relies in particular
on the MAC PAN Information Base
(MAC PIB) whose main element is the
Neighbour Table.
This table contains all the information that
the MAC and PHY levels need for
bidirectional communication with the
neighbours.
MAC Layer (Cont.)
The MAC Sublayer Management Entity (MLME) features the
following functions :

Active discovery (active scan) of neighbouring nodes.

Management of the MAC level parameters. These
parameters constitute the MAC Information Base (MAC
PIB).

Initialization/Reinitialization of the MAC and PHY layers.
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6LoWPAN Adaptation sublayer

In order not to compromise the speed of the OFDM PLC
links, the IPv6 and UDP headers are compressed.[rfc4944]
Reduces the IPv6 and UDP headers from 48 bytes to 5 bytes.

Calculation of the optimum route between two nodes A and
B of the PLC LAN using the LOAD protocol
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Network And Transport Layer

Network layer is based on the IPv6 protocol to ensure the
long-term continuity of the model.

Transport layer is UDP which provides unreliable transport to
datagrams in non-connected mode. Reliability of exchanges
within the PLC network is brought by the subjacent layers.

Other compression schemes shall be usable if necessary, such
as adaptive ROHCv2 compression [rfc4995] with its specific
profiles for TCP/IP [rfc4996] and UDP/IP [rfc5225]. In most
cases ROHCv2 manages to reduce header size to 2 bytes.
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Application Layer
The Applications stratum covers layers 5 to 7 in the OSI model.
The model proposed for metering is somewhat simplified and
comprises two broad classes of Applications :

Metering Application

Meter Management Application
It will be noted that all these applications rely natively on UDP.
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Metering Application
In the OFDM PLC profile the COSEM (能源計量配表規範)
Application strictly complies with the existing standards,
namely :

"COSEM Application Part" such as it is defined in [IEC
62056-61] and [IEC 62056-62]

"COSEM Application Layer" such as it is defined in [IEC
62056-53]

Security at Application level is ensured by the process
defined in [Blue Book].
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Metering Application (Cont.)
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Transport of the COSEM Application
protocol by UDP requires the
interpositioning of a "Wrapper" in
accordance with [IEC 62056-47]
Meter Management Applications
The Meter Management Applications feature three large
functional blocks:

A Management Agent

A Software Downloading system

An Initialization and Supervision system
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Management Agent
The Management Agent operates under the supervision of a
Manager function. they must address the different functional
domains :

Configuration Management, which allows the loading and
reading (GET/SET) of the parameters that control the
functioning of the Meter.

Fault and Alarm Management which ensures the supervision
of functioning of the meter, the detection, recording and
signalling of faults which are presented as Alarms

Statistics Management, which counts and logs all the
marking events
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Management Agent (Cont.)
The protocol used for exchanges between Management Agent
and Manager is SNMP (Simple Network Management Protocol)
in its latest version [rfc3416].
The security functions of SNMPv3 [rfc3414] turn out to be
relatively difficult to use. To maintain simplicity of deployment,
it is preferable not to activate them and to rely on the security
functions offered by the OFDM PLC MAC level.
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Software Downloading system

The firmware memory images are stored in a File Server.

The recommended downloading protocol is TFTP (Trivial
File Transfer Protocol) [rfc1350]. It is usually used for
unicast downloading, but a multicast version [rfc2090] is
also specified.
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Compare FTP with TFTP
Protocol
FTP
TFTP
傳輸協定
TCP，屬於連線導向，並
提供可靠的控制項。
UDP，需要較少的額外
負荷，並提供幾乎沒有
任何控制項。
執行方式
互動方式執行
單向傳輸的檔案
安全性
使用者驗證
沒有
Port
[20資料] [21連線]
[69 檔案傳輸活動]
速度
慢
快
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Software Downloading system (Cont.)
The downloading mechanism proper is that defined by the
BroadBand Forum. It provides for two methods:

Unmanaged downloading : The file server contacts the
equipment directly by sending it a TFTP Write-Request
(WRQ) message. In this case the transfer can only be unicast.

Managed downloading : the Managers sets the necessary
parameters in the equipment (URL of file to download,
timeout, etc.) then gives the equipment the order to start the
downloading. The equipment then contacts the file server by
sending it a TFTP RRQ (Read-Request) message. Transfer
can then take place in unicast or multicast mode after
negotiation. The server can accept it by returning a TFTP
OACK (Option-Acknowledge) message.
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Software Downloading system (Cont.)
The Memory Image files thus transferred must have the
following characteristics:

They must be natively in S format [rfc4194].

They must be compressed to GZIP format [rfc1952].

Each packet comprises:
•
A header including a preamble, the type of packet (version)
and the lengths of the list of commands and of the payload.
•
description, version, role of the file, actions on the file system,
timeouts, bootstrap, etc.
•
A block of signatures
•
The payload which contains one or more files.
Initialization and Supervision system
This system is responsible for sequencing the actions when
bootstrapping the meter, such as "active scan", launching of the
LBP/EAP/EAP-PSK protocol suite for authentication, distributing
the keys and the initial configuration.
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Conclusion
Benefits brought by the OFDM PLC profile :
 Data rates : 30kb/s for DQPSK modulation，15kb/s for
DBPSK modulation
 MAC level Security : they are simple，since they based on a
unique proof of identity (a 128-bit shared secret) and a single
cryptographic algorithm (AES-128)
 Architecture diversity and openness (IP) : can use IPv6
 Open Equipment Management (SNMP) : which reduces the
acquisition and operating costs, as is witnessed by its
widespread adoption by Network operators.
 Software (Firmware) management (TFTP) : Another example
of the benefits brought by the introduction of Internet
technologies is the use of standard protocols and tools for the
downloading and management of firmware.
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Thanks for Listening