Design and Implementation of Error Correcting Codes for Transmission in Binary Symmetric Channel

Error Correcting codes are normally used for protecting transmitted information bits in a noisy channel. The information bits are encoded into error correcting codes which will be transmitted into the channel and on the receiver side, the received codes will be decoded back into the transmitted information bits. In this paper, a technique of generating binary error correcting codes that meet the Gilbert-bound and a simple encoding-decoding mechanism will be presented. To show the performance of the error correcting codes, a Binary Symmetric Channel is considered for transmission

Investigation of Disturbances in Power Line Communications

In this thesis we investigate disturbances in Power Line Communications that influence data throughput of an orthogonal frequency-division multiplexing (OFDM) based transmissions. We found that data throughput is degraded not only because of low layer problems such as noise or interferences, but also because of high layer problems such as data packet size and the usage of a repeater in between a transmitter and a receiver. The first low layer problem considered in this thesis is Narrow-band Interference (NBI). We proposed an NBI model that is based on statistical properties. We proposed a QPSKOFDM coded modulation that performs well to combat the NBI. We also designed a new simple block code, called permutation code plus (PC+), to be concatenated with a Reed-Solomon (RS) code. Our proposed concatenated error-control code has a lower decoding complexity than the concatenation between RS and Convolutional Code (CC), used in the G3-PLC technology - one of the current OFDM based PLC technologies, while providing comparable error rate level (or performance), for hard decision decoding, in combating the NBI. The second low layer problem of interest in this thesis is impulsive noise (IN). We proposed a way to turn a parametric threshold based IN mitigation scheme into a nonparametric one. We proposed a new simple IN mitigation scheme, called replacement scheme, which delivers a better performance than the known clipping scheme. We also showed that our proposed joint clipping-replacement-nulling scheme delivers the best performance among all simple IN mitigation schemes. Furthermore, we introduced a new idea of combining existing simple IN mitigation schemes. This new combined scheme has a property that cannot be found in the traditional joint IN mitigation scheme, such as the clipping-nulling scheme. It guarantees to deliver the best performance of its individual combined schemes. Beside non-iterative IN mitigation schemes mentioned before, we proposed modifications on the Mengi-Häring iterative IN mitigation scheme that improve significantly the error rate level. We investigated G3-PLC technology performance based on a field trial test conducted in Hamburg (Germany), and identified the high layer problems mentioned before, that inuence its data throughput. We found that in order to have a good data throughput, big size packet transmission must be used instead of small packet size transmission. We also found that the location of a repeater in between a transmitter and a receiver plays an important role. The lack of knowledge to find a good location for a repeater results in data throughput degradation

Narrow-band interference model for OFDM systems for powerline communications

A narrow-band interference (NBI) noise model for the powerline communications channel is presented. We give details and analysis of the NBI noise model specifically for OFDM systems; it can easily be adapted to model NBI noise for other communications systems. We also show that by making the same assumptions as in the Middleton class A model, our NBI noise model becomes the Middleton Class A noise model

Penerapan Kamera Web Sebagai Pendeteksi Gerakan Dengan Antarmuka Directshow

Implementation of Web Cam as Motion Detector with DirectShow Interfacing. One of many ways to take control aweb cam is by using DirectShow which is integrated in DirectX. DirectShow acts like an API therefore it is easier touse. Afterwards, web cam will be implemented to detect object’s motion as well as camera surveillance. The method isby comparing a reference image with other image which is taken lately. If there are differences between those image itmeans motion has been detected

PENERAPAN KAMERA WEB SEBAGAI PENDETEKSI GERAKAN DENGAN ANTARMUKA DIRECTSHOW

Implementation of Web Cam as Motion Detector with DirectShow Interfacing. One of many ways to take control aweb cam is by using DirectShow which is integrated in DirectX. DirectShow acts like an API therefore it is easier touse. Afterwards, web cam will be implemented to detect object’s motion as well as camera surveillance. The method isby comparing a reference image with other image which is taken lately. If there are differences between those image itmeans motion has been detected.Keywords: motion detection, surveillance camer

Selected subcarriers QPSK-OFDM transmission schemes to combat frequency disturbances

To combat the impairments caused by frequency disturbances in the power line communications (PLC), a modified conventional QPSK-OFDM transmission scheme is presented. The idea of this scheme is to first group the N OFDM subcarriers into groups of M and then transmit data by selecting a subset of the subcarriers in the group. Real and imaginary parts of QPSK symbols are independently assigned to the selected subcarriers in a group, such that the minimum squared Euclidean distance is maximised. With this kind of symbol assignment to subcarriers our scheme has no net loss in terms of SNR requirements, in AWGN, in comparison to the conventional QPSK-OFDM, even though it has half the data rate of the conventional QPSK-OFDM. We refer to the conventional QPSK-OFDM as Scheme A. Our scheme displays a superior performance over Scheme A and another scheme (Scheme B), in the presence of frequency disturbances and also frequency selective fading noise. We further modify Scheme B and come up with additional two new QPSK-OFDM schemes that have better performance than Scheme B in AWGN and impulse noise. To encode, we apply a (n, k) RS code and a simple permutation code on the conventional QPSK-OFDM scheme, which significantly improves the decoder's performance in the presence of frequency disturbances. A simple narrow band noise model is developed and presented

Design And Implementation Of Error Correcting Codes For Transmission in Binary Symmetric Channel

Error Correcting codes are normally used for protecting transmitted information bits in a noisy channel. The information bits are encoded into error correcting codes which will be transmitted into the channel and on the receiver side, the received codes will be decoded back into the transmitted information bits. In this paper, a technique of generating binary error correcting codes that meet the Gilbert-bound and a simple encoding-decoding mechanism will be presented. To show the performance of the error correcting codes, a Binary Symmetric Channel is considered for transmission

Membangun Labs Tool Application Berbasis XML

Labs Tool Application is software, which is designed to help lecturers and teacher assistants having a multiple choice and simple answers model test. The software is able to randomly generate questions so that it can minimize students chance of cheating. Besides, it will also he able to check the answer automatically. In this case, the software will generate the questions in XML format