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Block Diagram of PLC G3 (from [6]). 

Block Diagram of PLC G3 (from [6]). 

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This paper gives an overview of Power Line Communications(PLC) and the different prevailing standards in PLC. The implementation of an OFDM transmitter - receiver system using MATLAB and Xilinx ZYNQ has been covered in detail in this paper. Additional links for tutorials on Hardware in loop testing and hardware software co-design can be found withi...

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... (EQ 4) is the IDFT of the transmit symbols; hence this can be achieved with the use of a IDFT block on the hardware. We can retrieve the original data by performing a serial to parallel conversion of the incoming data stream and performing an FFT on it. OFDM works well on an AWGN channel but when there is delayed dispersion in the medium, the orthogonality of the different subcarriers are affected and this might lead to Inter-Carrier Interference. Inter-Carrier Interference can be fought with the use of a Cyclic Prefix (CP). CP Insertion appends a part of the transmitted into the total signal. The Transmitted signal suffers real signal interference when echoes of the last part of a symbol interfere with the desired symbol; this is eliminated by calculating the T max for the channel and discarding the data received during that time interval. T is defined by The CP is especially useful when multipath signals are encountered [ 7]. OFDM gives Noise Immunity to signals in a very noisy environment, PLC puts forward similar problems and hence OFDM is commonly used in most PLC protocols. There are various protocols that are used in the industry for PLC, only time can tell which of these protocols can stand the test of time and can get widely accepted. This paper goes through two such protocols PRIME and G3. PRIME is the specification designed for narrow band PLC as shown in Figure 4; it is for low voltage lines with low noise levels and targets high data rates. PLC using PRIME take place in CENELEC (European Committee for Electro-technical Standardization) A band (41.9 to 88.8 kHz) using OFDM modulation with 97 sub carriers out of which 96 are for data. All the sub-carriers can be modulated with different modulation schemes like DQ-PSK (Dual-Polarization Phase Shift Keying), DB-PSK (Differential Binary Phase Shift Keying), D8-PSK (Differential – n Phase Shift Keying). The average transmission rate for the PHY layer is around 70 kbps and maximum is 128 kbps. PRIME convergence layer classifies traffic by associating it with proper MAC address. This helps in providing access to core MAC functionalities of system access, connection management and mesh topology resolution. The MAC layer provides function like system access, bandwidth allocation, connection establishment or maintenance and topology resolution. Physical layer transmits and receives data packets from neighbor nodes [3]. G3 is another prominent protocol for narrow band PLC communication as shown in Figure 5. G3 operates over CENELEC A band (3-95 kHz) in Europe and can be extended to full FCC band to provide a higher data rates in other countries. G3 was designed for medium voltage lines. G3 also uses an OFDM modulation technique; the sub-carriers can be modulated using DBPSK and DQPSK. It supports data rates up to 33.4 kbps under normal operation condition. G3 was designed to pass through transformers by enabling PLC signals [4]. Both these protocols are quite similar the following Table 1 shows a comparison between the two protocols and highlights the major differences among them. Although these results don’t prove that one protocol is better than the other, but it give a fair idea of the basic differences between these protocols [8]. The Smart Energy Communicator (SEC) is a subset of the research work done by the Smart Communication Research Group (SCRG) at RIT. Using power lines to send data over a long distance efficiently has been a dream since the time PLC technologies existed. In this project Matlab/Simulink are used to model a complete PLC system and a Xilinx Zynq 7000 SoC are used for hardware implementation. This system is designed to perform a simple OFDM modulation and demodulation; it uses Digilent Pmods for the Analog to Digital (A2D) and Digital to Analog (D2A) conversions while a Texas Instruments analog front end (AFE) could be used to inject and extract the analog signal into the power line. This project is not only a system for PLC but also a review on how we can use the power of Zynq SoC, in a hardware/software co-design to explore complex algorithm implementation using electronic system level (ESL) design with Matlab/Simulink. The efficiency on a software system with parallel hardware and to learn more about the Zynq based design as a growing tool for educators and designers. As disused earlier, OFDM modulation is prevalent in most PLC protocols standards and a basic OFDM transmitter/receiver was designed using Matlab Simulink toolbox. This made the design and implementation phase more ...