A Study Of Transmission Impairments and its purposed Solution in Power

Line Communication

Presented By:

Asim Shahzad (MCS02121005)

Tahir Zeb (MCS01111004)

PLCFeatures of PLC Technical of PLCApplications of PLCTransmission Impairments in PLCProposed Solution:

Agenda

• Power line Communication is the technology that enables the transmission of data over power line that carries and supplies electric power.

• PLC is a kind of communication technology, which uses Medium Voltage(MV) & Low Voltage(LV) distribution network as the communication media to implement transmission of data, voice and real time image

What is PLC?

•No new infrastructure installed . •Easy to interconnect devices through power grid. •Easy to install “plug and play” . •Using radio frequencies (RF) for data transmission . •Data rate 600bps to 45Mbps

Features of PLC

Technical of PLC

A block diagram model of data communication system

The Channel

Channel is designed to transfer the electricity .

Channel capable for data communication. Channel has limitation, regarding of noises

and interferences caused by electrical signals

Technical of PLC (Cont..)

Modulator and demodulator

• Frequency Shift Keying (FSK), using variety Frequency of carrier signal to present 1 and 0. • 4 possible baud rate (600Hz, 1.2kHz, 2.4kHz and 4.8kHz) . • Used for low data rate transfer 600bps-4.8kbps • Suitable to run in medium-voltage (10KV).

Technical of PLC (Cont..)

Modulator and demodulator(cont’d)

• Orthogonal Frequency Division Multiplexing (OFDM), using narrowband sub-carrier and multiplexed based on FDM

• Using HF (3-30MHz) .• Can achieve high data rate transfer (14- 45Mbps) . • Suitable works in low-voltages (110-240V) .

Technical of PLC (Cont..)

Channel encoder and decoder Used to reduce bit error, for instance, the convolution code technique.

Source encoder and decoder Used to compress and extract data, to avoid data redundancy.

Source and Destination Part of data communication, where the data start to transfer and end to receive.

Technical of PLC (Cont..)

Power line Modem(PLM) The communication device used for the communication over the power lines is a MODEM .

By using modulation techniques, binary data stream is keyed on to a carrier signal and then coupled on to the power lines by PLM. At the receiver end another PLM detects the signal and extracts the corresponding bit stream.

Technical of PLC (Cont..)

A diagram of PLM

Technical of PLC (Cont..)

A power line modem (PLM)

Technical of PLC (Cont..)

Applications of PLC

Meter Reading.

Automatic Meter Reading using PLCC technology ,saves a lot of human efforts and also makes the whole system more efficient. The automatic meter reading system consists of three components, namely, Multifunction Node (MFN), Concentrator & Communication Node (CCN) and Operation & Management System (OMS) .

Home Automation.Home automation or also known as Smart Home technology is a collection of systems and devices in a home that have an ability to interact with each other or function individually in order to be optimized in best way.

Applications of PLC (Cont..)

Home networking (LAN).Power line communications can also be used in a home to interconnect home computers and peripherals, and home entertainment devices that have an Ethernet port. Power line adapter sets plug into power outlets and establish an Ethernet connection using the existing electrical wiring in the home.

Applications of PLC (Cont..)

While transmitting data, voice and electricity simultaneously; there is big hurdle in data transmission which is transmission impairments.

Problem in PLC

1) Excessive Noise Level

• Noise and disturbance includes over-voltages, under voltages, frequency variation and so on.

• Household appliances like halogen tubes, washing machines, televisions, etc. can become prone to an unpredictable noise and interference in the transmission.

Transmission Impairments in PLC

2) Cable Attenuation

• As devices connected and disconnected from power network characteristics changes drastically

• This makes coupling a signal to power network difficult.

Transmission Impairments in PLC(Cont..)

Although there is no 100 % solution of any network impairments but the following device/technique are used to minimize the noise problem and cable attenuation in the PLC.

Proposed Solution:

Type M-1877 Noise SuppressionMTE Corporation type M-1877 Noise Suppression Network offers an economical solution to many facility interference problems caused by the high frequency emissions of adjustable speed drives and inverters Type M-1877 Noise Suppression Typical applications include:• AC Motor Drives• DC Motor Drives• Uninterruptible Power Supplies• Battery Chargers• Electronic Welders

Proposed Solution(cont..)

2nd Solution.Impulsive noise is the enemy of wideband spread spectrum it can knock out the data signals and as a results produce low data rates, even under normal condition and also produce no connectivity.

Adaptive network solution.Packets should be "small” and provide rapid synchronization so that a single error can be corrected by retransmitting one small packet rather than one large packet and as a result there will be less chance that it will get hit by noise.

Proposed Solution(cont..)

For this purpose we have to use the combination of two algorithms “Low density Parity-check(LDPC)” and “Signal to Noise ratio (SNR)” for our adoptive network solution.

Proposed Solution(cont..)