Informatics Publishing Limited

Jaspal Singh ¹, Divya Dhawan ², Lalit Kumar ²

Affiliations
1 CDAC, Phase 7, Mohali, IN
2 PEC University of Technology, Sector 12-A, Chandigarh, IN

Abstract

Agriculture, the backbone of human sustenance on earth needs continuous innovations of new technologies and betterments in the already existing methods. Apart from providing the nourishment to the world’s population, it also holds the badge of being the source of income for millions of people around the globe. Greenhouses came into inception so as to enable cultivation of crops in areas where environmental conditions are not so friendly and also during off-season in main agricultural areas. Humidity and temperature control allows greenhouses to turn an inarable (infertile) piece of land into arable (fertile) land, thereby improving food production in terms of quality and quantity. Therefore, monitoring of the crucial factors like humidity and temperature of a greenhouse environment is must, to make it reliable and efficient agricultural practice. The proposed system “Greenhouse Environment Monitoring System using ZigBee based Ad-Hoc network” is an endeavour to monitor humidity and temperature inside a Greenhouse. This versatile system can be used inside a single greenhouse or to gather data from several greenhouses in a field to precisely control the humiture in respective greenhouses.

Keywords

Greenhouses, Wireless Personal Area Networks (WPANs), ZigBee.

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Neena Gupta ¹, Divya Dhawan ¹, Kadam Bhambri ¹, Gagandeep Kaur Jayjee ¹

Affiliations
1 PEC University of Technology, Sector 12-A, Chandigarh, IN

Abstract

The authors have developed, simulated and analyzed the performance of SOA-based all-optical OR and NOT gates at 10 Gbps. Furthermore, the all-optical NOR gate has been designed and its implementation has been done successfully by cascading OR with NOT gate. The proposed design is simpler in structure and offers flexibility in wavelength selection. Also, it allows scope for photonic integration which is imperative to realize higher level components like half-adder, full-adder etc. In comparison to previously postulated works, SOA based gates offer wide bandwidth and simplicity in structure. Also, majority of the designs in literature work upto 10 Gbps. However, the proposed design of OR, NOT and NOR gates can be operated upto 30 Gbps.

Keywords

All-Optical Gates (OR, NOT, NOR), Cross Gain Modulation (XGM), Cross Phase Modulation (XPM), Semiconductor Optical Amplifiers (SOAs).

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Prabhmandeep Kaur ¹, Divya Dhawan ¹

Affiliations
1 PEC University of Technology, Sector-12, Chandigarh, IN

Abstract

This paper presents a design approach for low-density parity-check (LDPC) encoder and decoder for applications in optical communication systems at 40 Gb/s. In order to get the best performance, the system is further optimized for the powers of the EDFA (Erbium Doped Fiber Amplifier) amplifiers used with the SMF (Single Mode Fiber) and DCF (Dispersion Compensating Fiber) fibers to achieve the highest Q factor. The designed LDPC coded system (using LDPC codes of r=0.8 for coding and sum-product algorithm (SPA) for decoding) is compared with the uncoded system at bit rate of 40 Gb/s and seen to provide significant performance improvement in terms of the BER. LDPC codes also provide near-capacity performance and significant system enhancement with respect to the state-of-the-art FEC (Forward Error Correction) schemes. High coding gains and their inherent low complexity of both the encoder and decoder have made them an attractive and viable choice for high-speed optical communication.

Keywords

Forward Error Correction (FEC), Low Density Parity Check (LDPC) Codes, Sum Product Algorithm (SPA).

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Divya Dhawan ¹, Neena Gupta ², Raj Bala ³

Affiliations
1 Department of Electronics and Electrical Communication Engineering, PEC University of Technology, Chandigarh, IN
2 Department of Electronics and Electrical Communication Engineering, PEC University of Technology, Chandigarh, IN
3 Punjab Engineering College, Chandigarh, IN

Abstract

Next generation services of triple play (data/voice/video) require far more bandwidth than prevailing technologies like dial-up, Integrated Services for Digital Network (ISDN), cable, Digital Subscriber Line (DSL) could offer. The bay between the access and metro networks is broadening due to bandwidth difference. This problem is termed as “access bottleneck”. The challenge is to distribute triple play services efficiently and cost effectively. Passive optical network has addressed these challenges in a most auspicious manner. This paper presents an architecture supporting triple play services. It employs Broadband Passive Optical Network (BPON) within last mile to address the access bottleneck issue. It uses orthogonal frequency division multiplexing (OFDM) for transmission of voice, video and data service. Performance analysis of our proposed architecture using simulation technique shows that the signal power received at the farthest Optical Network Unit (ONU) after passing through a distance of 25km is -25dBm with a satisfactory bit error rate (BER) of 10-3 and a Signal to Noise Ratio for video service, indicating good and clear picture quality. Proposed method not only accomplishes the desired requirement for availing services of data/voice/video (triple play) but also achieves its objective cost effectively.

Keywords

Broadband Passive Optical Network (BPON), Fiber to the Home (FTTH), Orthogonal Frequency Division Multiplexing (OFDM), PON (Passive Optical Network), Triple Play.

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Neena Gupta ¹, Divya Dhawan ¹, Preety Singla ²

Affiliations
1 Electronics and Electrical Communication (E&EC) Department, PEC University of Technology, Chandigarh, IN
2 Electronics and Electrical Communication (E&EC) Department, PEC University of Technology, Chandigarh, IN

Abstract

Free Space Optics (FSO) takes a line-of-sight approach in telecommunications, in which modulated infrared laser light is transmitted through the air. A need was felt to design FSO system having more powerful source, for longer transmission system as well as to tab the full potential of available optical bandwidth. In the previous work, authors used various OCDMA techniques for multiplexing to achieved a permissible BER > 10^-5and a speed less than 5 Gbps. This paper demonstrates the Optical Code Division Multiple Access Pseudo-orthogonal ―Flattened matrix codes in Free Space Optical Communication. In the present work authors design a system in which high speed information at 10 Gbps bit rate is successfully broadcasted from transmitter station to the receiver station at the link range of 500m through the Free Space channel at wavelength of 1550nm using an OCDMA pseudo-orthogonal encoder and decoder. The results are discussed in terms of bit error rate and quality factor with maximum number of users that can withstand by this communication system. This system can support sixteen simultaneous users and at an acceptable bit error rate e^-9 less.

Keywords

Bit Error Rate (BER), Free Space Optics (FSO), Optical Code Division Multiple Access (OCDMA), Pseudo-Orthogonal Codes.

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Vandana Kumari ¹, Divya Dhawan ¹

Affiliations
1 University of Technology, Chandigarh, IN

Abstract

The explosive increase in the number of Internet users boost the demand for high speed data capacity in Access networks, Metro networks and especially in Core networks. The systems with 10 Gbit/s and 40 Gbit/s have already seen much of the research and now the focus has shifted to even higher datarates of 100 Gbit/s and 160 Gbit/s per wavelength. Since optical data transmission with conventional modulation formats based on on-off-keying (OOK) at such high datarates is adversely affected by linear and non-linear effects, it’s important to look at other modulation formats offering resistance to these effects. Polarization Multiplexing Quadrature Phase Shift Keying PM-QPSK is one such modulation format which must be studied at ultra-high data rate of 160 Gbit/s. In this paper the performance of a single channel PM-QPSK having datarate of 160 Gbit/s has been investigated with coherent detection of the optical signal along with the digital signal processing for dispersion compensation in a scenario of rapid increase in demand for datarate. Here the study has been carried out on 900kms of uncompensated SSMF and NZDSF with the different launch powers and also OSNR requirement for the system in back to back configuration has been derived. Also an increase in optical reach has been achieved through two methods first being Distributed Raman Amplification (DRA) and pump power has been optimized for the same and second by using shorter fiber spans with EDFA amplification only.

Keywords

Coherent Detection, DSP, Optical Fibre Communication, PM-QPSK.

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Jasjot Kaur Sahota ¹, Divya Dhawan ¹

Affiliations
1 Electronics and Communication Engineering Department, PEC University of Technology, Chandigarh, IN

Abstract

Nowadays, Free Space Optics (FSO) is gaining a lot of popularity, as it offers more advantages than other communication systems like licence-free operation, high data transmission rates etc. The major drawback of this system is the atmospheric turbulence since the medium that is used in this system is air. Orthogonal frequency-division multiplexing (OFDM) is a method of digital signal modulation in which a single data stream is divided into several separate narrowband channels at different frequencies. One of the main advantages of OFDM is that it is more resistant to frequency selective fading because it divides the overall channel into multiple narrowband signals that are affected individually as flat fading sub-channels. Using FSO system in combination with Orthogonal Frequency Division Multiplexing (OFDM) scheme, the bad influence of atmosphere can be overcome. There are different methods to mitigate the bad influence of turbulence in OFDM-FSO system which is discussed in this paper.

Keywords

Atmospheric Turbulence, Free Space Optics (FSO), Orthogonal Frequency Division Multiplexing (OFDM), Radio Over Free Space Optics (ROFSO).

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