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Article
LDPC Coded Multiuser MC-CDMA Performance Overmultipath Rayleigh Fading Channel
منظومة (LDPC-MCCDMA) متعدد المستخدمين

Author: Aqiel N. Almaamory
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2011 Volume: 17 Issue: 4 Pages: 1039-1046
Publisher: Baghdad University جامعة بغداد

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Abstract

This work presents the simulation of a Low density Parity Check (LDPC) coding scheme with multiuserMulti-Carrier Code Division Multiple Access (MC-CDMA) system over Additive White Gaussian Noise (AWGN) channel and multipath fading channels. The decoding technique used in the simulation was iterative decoding since it gives maximum efficiency with ten iterations. Modulation schemes that used are Phase Shift Keying (BPSK, QPSK and 16 PSK), along with the Orthogonal Frequency Division Multiplexing (OFDM). A 12 pilot carrier were used in the estimator to compensate channel effect. The channel model used is Long Term Evolution (LTE) channel with Technical Specification TS 25.101v2.10 and 5 MHz bandwidth including the channels of indoor to outdoor/ pedestrian channel and Vehicular channel.

يقدم هذا العمل محاكاة (LDPC ) مع (MC-CDMA)متعدد المستخدمين خلال قناة (AWGN) وقناة الخفوت متعدد المسارات . تقنية فتح الشفرات المستخدمة في البحث هي فك الشفرات التكراري لأنه يعطي الكفاءة القصوى مع عشرة تكرارات . نوعيات التضمين المتبعة هي (BPSK,QPSK,16PSK) مع (OFDM) . القناة المستخدمة في النموذج هي قناة الجيل الثالث ( LTE( ذات المواصفات التقنية TS 25.101v2.10مع عرض قناة مقداره 5MHzوتشمل القنوات داخل وخارج ألابنيه والقنوات المتحركة.


Article
Joint Hybrid Compression Techniques and Convolutional Coding for Wireless Lossy Image Transmissions

Authors: Salah Al-iesawi1 --- Maha Abd Rajab2 --- Ahmed I. A.3
Journal: IRAQI JOURNAL OF COMPUTERS,COMMUNICATION AND CONTROL & SYSTEMS ENGINEERING المجلة العراقية لهندسة الحاسبات والاتصالات والسيطرة والنظم ISSN: 18119212 Year: 2015 Volume: 15 Issue: 1 Pages: 80-99
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Abstract – This paper demonstrates the effect of color image transmission through AWGN channel using binary phase shift key modulation (BPSK) system and transmission of compressed color image through AWGN. On the other hand, the transmission consumes a large amount of channel and needs the processing, therefore utilizes compression techniques to reduce the size of the original color image to facilitate the transmission compressed color image through AWGN and to obtain the channel optimization. In this paper, a simple hybrid lossy color image compression transmission through AWGN using convolutional coding with Viterbi decoding system is proposed. It is based on combining effective techniques, started by wavelet transform that decompose the image signal followed by polynomial approximation model of linear based to compress approximation image band. The error caused by applying polynomial approximation is coded using bit plane slice coding, whereas the absolute moment block truncation coding exploited to coded the detail sub bands. Then, the compressed information encoded using LZW, run length coding and Huffman coding techniques, the compressed information is entered to the channel coding to coded the information using convolutional coding and modulation using BPSK to transmit through channel and added AWGN, the received signal is demodulated and decoded using Viterbi decoding, the result compressed data passed to source decoding to reconstruct the compressed image. The test results indicated that the proposed system can produce a balance between the compression performance and preserving the image quality, and also simulations results observed that with increase in signal to noise ratio (SNR) values the bit error rate (BER) values decrease.


Article
Performance Evaluation and Comparison Between LDPC and Turbo Coded MC-CDMA
تقييم و مقارنة كفاءة LDPC and Turbo Coded MC-CDMA

Authors: Husam Abduldaem. Mohammed حسام عبد الدائم محمد --- Aqiel N. Almaamory عقيل نعمه المعموري
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2012 Volume: 18 Issue: 4 Pages: 433-442
Publisher: Baghdad University جامعة بغداد

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Abstract

This work presents a comparison between the Convolutional Encoding CE, Parallel Turbo code and Low density Parity Check (LDPC) coding schemes with a MultiUser Single Output MUSO Multi-Carrier Code Division Multiple Access (MC-CDMA) system over multipath fading channels. The decoding technique used in the simulation was iterative decoding since it gives maximum efficiency at higher iterations. Modulation schemes used is Quadrature Amplitude Modulation QAM. An 8 pilot carrier were used to compensate channel effect with Least Square Estimation method. The channel model used is Long Term Evolution (LTE) channel with Technical Specification TS 25.101v2.10 and 5 MHz bandwidth bandwidth including the channels of indoor to outdoor/ pedestrian channel and Vehicular channel. The results showed that the performance of the proposed system was better when the LDPC was used as a coding technique.

يقدم هذا العمل مقارنة ل Convolutional Encoding CE, Parallel Turbo code and Low density Parity Check (LDPC) coding schemes مع نظام (MC-CDMA) متعدد المستخدمين ذو الخرج المفرد خلال قناة الخفوت متعدد المسارات. تقنية فتح الشفرات المستخدمة في البحث هي فك الشفرات التكراري لأنه يعطي الكفاءة القصوى مع عشرة تكرارات . نوعيات التضمين المتبعة هي .Quadrature Amplitude Modulation QAM تم استخدام 8 pilot carriers لمعادلة تأثيرالقناة مع .Least Square Estimation methodالقناة المستخدمة في النموذج هي قناة الجيل الثالث (LTE) ذات المواصفات التقنية TS25.101v2.10 مع عرض قناة مقداره 5MHz وتشمل القنوات داخل وخارج ألابنيه والقنوات المتحركة. بينت النتائج ان كفاءة النظام المقترح افضل مع تقنية تشفير ال LDPC.


Article
Evaluating the Efficiency of Video Transmission Using a New Circular Search Algorithm Based on the Motion Estimation for a Single User

Authors: Shaymaa T. Ahmed --- bSeba A.Sahy
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2018 Volume: 26 Issue: 7 Pages: 219-230
Publisher: Babylon University جامعة بابل

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Abstract

The successful transmission of video over wireless networks faces many challenges and problems that contribute to the weakening of efficient transmission systems because of the limited resources and the environment surrounding the wireless signal. Therefore, In order to deal with these challenges we need not only to compress the video in efficient ways but also to use a good transmission system that overcome the errors of the channel and correct potential errors during the transmission process. In this paper, the transmission system depends on the transmission of the video to a single user, a proposed system to simulate the transmission in the mobile networks and to measure the efficiency of the transmission system is added to the percentage of noise (i.e. additive white Gaussian Noise (AWGN) channels). In many such practical systems, jointly source and channel coding the efficiency and performance of the transmission system can be greatly improved to obtain a transmission system without channel errors. The source coding decreases the redundancy in the signal sent to provide bandwidth and the channel/convolutional coding (CC) adds useful redundancy to combat channel errors. The circular search algorithm for motion estimation (ME) is used as a source coding method. The results show that the suggested system can produce a balance among the compression performance and maintain video quality. The methods used in the transmission process showed a great advantage in the performance of the channel encoding compared to that of another transmission system without channel coding.

ويواجه البث الناجح للفيديو عبر الشبكات اللاسلكية العديد من التحديات والمشاكل التي تسهم في إضعاف أنظمة الإرسال الفعالة بسبب محدودية الموارد والبيئة المحيطة بالإشارة اللاسلكية. لذلك، من أجل التعامل مع هذه التحديات نحن بحاجة ليس فقط لضغط الفيديو بطرق فعالة ولكن أيضا لاستخدام نظام نقل جيد التغلب على أخطاء القناة وتصحيح الأخطاء المحتملة أثناء عملية الإرسال. وفي هذه الورقة، يعتمد نظام الإرسال على إرسال الفيديو إلى مستعمل واحد، ويضاف نظام مقترح لمحاكاة الإرسال في الشبكات المتنقلة وقياس كفاءة نظام الإرسال إلى نسبة الضوضاء (أي أبيض مضاف قنوات الضوضاء. وفي كثير من هذه الأنظمة العملية، يمكن أن يحسن المصدر المشترك والقناة التي تشفر كفاءة وأداء نظام الإرسال تحسنا كبيرا للحصول على نظام إرسال دون أخطاء في القناة. ويؤدي تشفير المصدر إلى تقليل التكرار في الإشارة المرسلة لتوفير عرض النطاق ويضيف التشفير القناة / التلافي تكرارا مفيدا لمكافحة أخطاء القناة. وتستخدم خوارزمية البحث الدائرية لتقدير الحركة كطريقة ترميز المصدر. وتظهر النتائج أن النظام المقترح يمكن أن يحقق التوازن بين أداء الضغط والحفاظ على جودة الفيديو. وأظهرت الأساليب المستخدمة في عملية الإرسال ميزة كبيرة في أداء تشفير القناة مقارنة بأداء نظام إرسال آخر دون تشفير القناة


Article
BER, Throughput, Energy Efficiency Performance Analysis of Proposed Different Systems in Wireless Sensor Network

Authors: Wa'il A. H. Hadi --- Safa A. A. Abass
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 11 Part (A) Engineering Pages: 1970-1978
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

One of the major weakness of Wireless Sensor Networks is the energy consumption because of limited battery resource and battery replacement or recharging difficulty. The research presented in this paper aims to reduce the energy consumption in the physical layer because most the energy consumption occurred in this layer. This reduction will be achieved via the use of ZigBee transceiver standard at the physical layer under 2.4GHz frequency band with the reduced complexity and lower power consumption than other techniques used in Wireless Sensor Network. Furthermore, such use will also enhance energy efficiency, bit error rate, and throughput of the wireless sensor network. In this paper, three different systems have been proposed according to the type of transceiver technique used in wireless sensor network. System1 uses ZigBee transceiver standard over the wireless sensor network without any additional technique whereas system2 uses ZigBee transceiver with Convolutional Coding over the WSNs model. On the other hand, system3 uses the ZigBee transceiver with both diversity techniquesVirtual Multi-Input Multi-Output and with Convolutional Coding over the wireless sensor network model. The simulation of matlab results show that system3 achieves the best energy efficiency performance compared with the other two systems at lower quality of channel. System2 achieves the best energy efficiency performance at medium quality of channel, and system1 achieves better energy efficiency at high quality of channel.

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