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Relay-Aided Communication Schemes for Wilreless Multiple Access and Multicast Channels

Thesis Info

Access Option

External Link

Author

Chattha, Jawwad Nasar

Program

PhD

Institute

Lahore University of Management Sciences

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Electrical Engineering

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/10644/1/Jawwad_Nasar_Chatta_Electrical_Engineering_2018_LUMS_24.05.2019.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727821651

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User cooperation through relaying is a powerful tool to combat fading and to increase robustness of wireless networks. This thesis explores cooperative schemes for wireless multiple access and multicast channels in the presence of a single dedicated relay. Novel cooperative schemes presented here are based upon relay performing decode-and-forward (DF), noisy network coding (NNC) or a combination of both DF and NNC. The first half of this thesis presents cooperative schemes for a multiple access channel. It considers an uplink non-orthogonal multiple access relay channel (NOMARC) in which multiple users wish to communicate to a single base-station (BS) with the help of a single dedicated relay. Firstly for a two- user setup, we derive the improved achievable rate region by employing NNC-only relaying as opposed to conventional compress-and-forward (CF) relaying. Next, for the multiple user setup, we propose a novel Joint NNC-DF (J-NNC-DF) scheme that utilizes DF cooperation when messages from all user are successfully decoded at the relay and NNC when the relay is unable to decode message of any one of the users. In the scenario when the relay is capable of successfully decoding messages from only a subset of users, J-NNC-DF performs joint DF and NNC encoding with DF applied to the set of messages that were decoded successfully, and NNC for the set of messages that were not decoded successfully. After presenting the achievable rate regions, we derive closed form expression for probability of outage for the proposed schemes. These outage expressions permit selection of optimal quantizer noise variance selection to minimize probability of outage. Both analysis and simulations confirm that the proposed J-NNC-DF scheme outperforms other existing benchmarks such as DF-only, NNC-only and NNC-or-DF. In the second part of this dissertation, we propose a cooperative scheme for a downlink multicast network in which a BS wishes to communicate the same message to multiple users with the help of a single dedicated relay. For this setup, we propose a layered multiplexed-coded decode-and-forward (LMDF) relaying scheme. This scheme comprises of two major components: layering at the BS and mulitplexed DF encoding at the relay. BS message is split into two layers, independentlyencoded and mapped to a quadrature amplitude modulated (QAM) constellation, thus achieving superposition. The benefit of superposition coding of the two layers is that it allows partial message recovery at the relay and the users. On the other hand, multiplexed coding at the relay enables each user to divert all channel resources towards decoding the layer(s) that remains unrecoverable from the BS’s transmission. After deriving achievable rate regions, performance comparison is carried out for the proposed schemes against superposition coded and unlayered BS transmissions. In short, the dissertation proposes, analyzes and simulates J-NNC-DF and LMDF as viable candidates for future generation wireless communication networks.
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۳-متی

۳-متی

"أَمْ حَسِبْتُمْ أَن تَدْخُلُواْ ٱلْجَنَّةَ وَلَمَّا يَأْتِكُم مَّثَلُ ٱلَّذِينَ خَلَوْاْ مِن قَبْلِكُم مَّسَّتْهُمُ ٱلْبَأْسَآءُ وَٱلضَّرَّآءُ وَزُلْزِلُواْ حَتَّىٰ يَقُولَ ٱلرَّسُولُ وَٱلَّذِينَ آمَنُواْ مَعَهُ مَتَىٰ نَصْرُ ٱللَّهِ أَلا إِنَّ نَصْرَ ٱللَّهِ قَرِيبٌ۔"[[1]]

"پھر کیا تم لوگوں نے یہ سمجھ رکھا ہے کہ یونہی جنت کا داخلہ تمہیں مل جائے گا، حالانکہ ابھی تم پر وہ سب کچھ نہیں گزرا ہے، جو تم سے پہلے ایمان لانے والوں پر گزر چکا ہے؟ اُن پر سختیاں گزریں، مصیبتیں آئیں، ہلا مارے گئے، حتیٰ کہ وقت کارسول اور اس کے ساتھی اہل ایمان چیخ اٹھے کہ اللہ کی مدد کب آئے گی اُس وقت انہیں تسلی دی گئی کہ ہاں اللہ کی مدد قریب ہے"۔



[[1]]     القرآن ،۲ : ۲۱۴۔

SINERGITAS PENGEMBANGAN KURIKULUM PAI DALAM PENDIDIKAN

Islamic education curriculum has central value for education process, as education vision direction. Islamic education mission is how to create religious people by leaning perfectly. Curriculum becomes one of success applications and quality in education institution most. Curriculum will develop based on global world and people life style existency. Therefore, education should view people life style increased as learning source that is becomed a value for curriculum step making. Beside that, islamic education curriculum development also becomes teacher’s choice to implement learning manner in class. In where, it’s implementation should be arranged and systematically to make maximal learning either in development vision, indicator, lesson teory, lesson model proccess, learning evaluation or teacher’s development skill. The process of islamic education curriculum development  must be done good and awesome also seeing several factors as supports and obstacles of it. In other to get an education result based on such the plan made before(education planning).

Biodegradation of Azo Dyes by Bacterial Cells and Azoreductase

Azo dyes are widely used by different industries including the textile industry. In Pakistan, dye-containing industrial wastewater is commonly used to irrigate crops, which leads to the contamination of agricultural soils. These azo dyes may influence soil microbes adversely. Hence, a study was conducted to assess the persistence of azo dyes in soil and their impact on soil microbial community structural changes. Furthermore, biodegradation of these azo dyes by bacterial cells and enzyme azoreductase was examined in the liquid medium. Three azo dyes such as Direct Red 81, Reactive Black 5 and Acid Yellow 19 were added into 10 g soil at concentration of 160 mg kg-1 soil. Azo dyes were found to be quite stable and degraded slowly in the soil. A substantial amount of Direct Red 81 (63.5%), Reactive Black 5 (17.3%) and Acid Yellow 19 (24.6%) was recovered from soil upon treatment with a mixture of four solvents (water, methanol, acetone, chloroform, 1:1:1:1 v/v) after 14 days of spiking. Phospholipid fatty acid (PLFA) analysis showed significant changes in the soil microbial community structure after treatment of the soil with azo dyes compared to untreated soil. To prevent contamination of soil, dye-contaminated wastewater discharged by dyeing units requires treatment prior to its release into water streams and soil. For this purpose, thirty bacterial strains capable of degrading azo dyes were isolated from wastewater of textile industry. Isolate IFN4 was identified by 16S rRNA gene sequencing. It belonged to genus Shewanella and was named as Shewanella sp. strain IFN4. This bacterium was highly efficient in decolorizing four, structurally different azo dyes (200 mg L-1) individually as well as in mixture, and 72-99% decolorization was achieved just in 4 h under static incubation. Optimum pH and temperature for the decolorization of dye mixtures were 8.5 and 35 °C, respectively. Decolorization of the dyes was dependent on the presence of co-substrate in medium, and yeast extract was used preferably by the strain IFN4 as a co-substrate for the decolorization of dye mixtures compared to other co-substrates. Maximum decolorization occurred when the dye solution was supplemented with 6 g L-1 yeast extract. Moreover, azoreductase activity of strain IFN4 was significantly higher in the dye solution containing 2 g L-1 yeast extract (4.19 U/mg proteins) than that observed without yeast extract (1.32 U/mg proteins). Michaelis-Menten kinetics was employed to calculate Km and Vmax values for crude proteins of strain IFN4, and were 0.062 g L-1 yeast extract and 4.44 U/mg proteins, respectively. Among the components (riboflavin, pyridoxine and thiamine) of yeast extract, only riboflavin enhanced the decolorization of azo dyes by bacterial cells and azoreductase. Textile wastewater contains toxic heavy metals and salts, thus decolorizing activity of strain IFN4 and its azoreductase was evaluated in the presence of various metals and salts. The decolorization efficiency of Shewanella sp. strain IFN4 was not affected by the addition of Ni2+, Cr2+, Pb2+, Fe3+ and Mn2+ in liquid medium containing 200 mg L-1 Reactive Black 5. However, addition of Cu2+, Zn2+, Co2+ and Cd2+ substantially reduced the decolorization rate. Cd2+ was highly toxic as no decolorization was observed at concentration of 10 mg L-1. In contrast, strain IFN4 was able to decolorize Reactive Black 5 dye efficiently in the presence of metal ion mixture with concentration up to 15 mg L-1 dye solution. The results also revealed that Zn2+, Co2+, Cd2+ and Cu2+ inhibited bacterial growth while Fe3+ and Mn2+ enhanced it. The metal ions did not cause a significant inhibition in the azoreductase activity except Cu2+. Furthermore, strain IFN4 was able to decolorize Reactive Black 5 at salt concentration of 50 g NaCl L-1 and 60 g Na2SO4 L-1. However, this strain was unable to decolorize Reactive Black 5 in the presence of even 2 g NaNO3 L-1 medium. Azoreductase activity of strain IFN4 was not significantly decreased at salt concentration of 30 and 60 g L-1 Na2SO4 and NaCl, respectively. However, a significant inhibition in the enzyme activity was observed above these concentrations. Moreover, azoreductase of strain IFN4 showed broad substrate specificity and maximum decolorization of azo dyes was observed at pH 8.0 and 45 °C. Azoreductase activity was dependent on coenzymes (NADH or NADPH), flavin and quinone compounds as enzyme activity increased by their presence in the assay. The azoreductase of Shewanella sp. strain IFN4 had a molecular mass of 33±0.5 kDa and was identified as Na (+)-translocating NADH-quinone reductase subunit F. This study suggested that Shewanella sp. strain IFN4 and its azoreductase are the potential tools to treat textile wastewater.