Search or add a thesis

Advanced Search (Beta)
Home > Analysis of Decoupled User Association in Multi-Tier 5G Heterogeneous Cellular Networks

Analysis of Decoupled User Association in Multi-Tier 5G Heterogeneous Cellular Networks

Thesis Info

Access Option

External Link

Author

Sial, Muhammad Nadeem

Supervisor

Junaid Ahmed

Program

PhD

Institute

COMSATS University Islamabad

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2018

Thesis Completion Status

Completed

Subject

Electrical Engineering

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/13612/1/PhDThesisNadeem-V8.0-03May2018-ScansIncluded-2.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727701660

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


High data rate demands of users have resulted into initiation of research on 5th Generation (5G) mobile networks. Up till now, Heterogeneous Networks (HetNets), Massive Multiple-Input Multiple Output (MIMO) and millimeter Wave (mmWave) technologies have been identified as key enabling technologies for emerging 5G networks. Out of these, HetNets along with efficient user association mechanisms are considered the most promising technology to achieve desired 5G objectives. At present, the cell association in existing HetNets is based on Downlink Reference Signal Received Power (DL RSRP) termed as coupled association which results into sub-optimal user performance, asymmetric load distributions and mobility management due to coverage areas asymmetries in HetNets. In order to improve existing HetNet user association, Downlink-Uplink Decoupling (DUDe) and biased cell association techniques have been proposed in literature. Out of these, the concept of DUDe has been recently introduced to address the shortcomings of coupled and biased cell user association. In DUDe, mobile may receive DL traffic from one BS based on DL RSRP and send UL traffic through another base-station (BS) based on the path loss. The DUDe can also be jointly used with dual connectivity to consume radio resources of at least two different network points for spectrum aggregation. Currently, some initial research on decoupled access has been undertaken but analysis in realistic scenarios is still an open research area. In the prior works, all network users are assumed to utilize decoupled access without considering its necessity and viability along with user location. Moreover, insights on the decoupling effects in terms of number of HetNet tiers and degree of HetNet densities has not been presented in the literature. The use of decoupled access with dual connectivity has also not been analyzed in multi-tier settings. In this research work, we propose a new and practical hybrid coupled / decoupled and Joint DUDe Dual Connectivity cell association schemes for K-tier HetNets which can be selected depending upon user location and by considering its benefits. Due to proposed scheme, one type of users can have UL-DL Coupled Association (CoA) with same BS despite the permissibility of decoupled association. Second type of users can follow UL-DL decoupled access called DUDe association policy. This type of user association in which users can have both coupled or decoupled access is called hybrid coupled / decoupled. In the thesis, analysis starts by examining the basic form of hybrid coupled / decoupled in two tier HetNets where UL and DL associations are based on path loss and DL received power respectively. Later on, the analysis is further extended for K-tier HetNets to generalize the analytical model. This analysis is followed by analytical modeling of Joint DUDe Dual Connectivity where user is allowed to aggregate channels based on Dual Connectivity along with Decoupled Access. With the use of stochastic geometry, we have developed closed form solutions for coverage, outage probabilities and average throughput by considering uplink power control, receiver noise and K-tiers of HetNets which is not available in the existing literature. The resultant performance metrics are also evaluated in terms of achieved gains over existing coupled access policies. Results show that cell association technique based on DUDe or Joint DUDe Dual Connectivity can significantly improve UL performance for forthcoming 5G HetNets in terms of coverage probability, outage probability and average throughput. Finally, the thesis is concluded by a summary of the findings and main outcomes from the conducted research along with suggested future directions.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

شیخ ظہور الحسن

شیخ ظہور الحسن
افسوس ہے کہ شیخ ظہورالحسن صاحب سابق ریوینیو سکریٹری حکومت اتر پردیش نے کراچی میں انتقال کیا، وہ اپنے محکمہ کے ماہر اور اس صوبے کے لائق ترین عہدہ داروں میں تھے، حکومت میں ان کا بڑا وقار تھا، عملاً بڑے مذہبی اور دیندار تھے، مذہبی مطالعہ وسیع تھا، دینی کاموں سے بڑی دلچسپی تھی، ترک وطن سے پہلے دارالمصنفین کی مجلس انتظامیہ کے رکن تھے، کئی سال ہوئے ریٹائرڈ ہوچکے تھے، ان کے لڑکے پاکستان میں بڑے عہدوں پر تھے، لیکن وہ خود ہندوستان ہی میں مقیم رہے، ۱۹۶۵؁ء کی جنگ سے کچھ پہلے لڑکوں سے ملنے کراچی گئے تھے، اسی دوران میں جنگ چھڑگئی، اس لیے لڑکوں کے اصرار سے وہاں مستقل قیام اختیار کرلیا، اور وہیں قلبی دورے میں وفات پائی، مسلمان عہدہ داروں میں ایسے لائق اور دیندار کم ہوتے ہیں، اﷲ تعالیٰ اس مرد مومن کی مغفرت فرمائے۔ (شاہ معین الدین ندوی، جنوری ۱۹۷۲ء)

طبی میدان عمل میں ضرورت کی بنیاد پر رخصت کا اطلاق

This research article discusses optimal concessions (Al-Rukhsa) in light of the views of Jursists  in medical context. The study adopted an analytical method to analyze Quranic Verses, Ahadith and the principles of Fiqh and reliable classical juristic writings  related to this particular topic. The study came up with several results and one of the important results is the emphasis on the permissiblity of the idea of looking for the optimal concessions to be acceptable if certain conditions and criteria are duly fulfilled. It also conclude that the reforms of islamic laws as well as juristic thoughts in the modern era can not oppose the Islamic fundamentals related to the idea of religious information as long as that refarmation does not atter the fundamentals of Islam.

Frequency and Association of Cytokine Gene Polymorphisms in Tuberculosis Disease Susceptibility and Severity

One third of the world’s population is suspected to be infected with Mycobacterium tuberculosis with an estimation of 8-10 million new cases diagnosed annually. Despite low contribution from the human immunodeficiency virus, Pakistan is among the 22 high tuberculosis (TB) burden countries worldwide. Among the several factors that contribute towards the susceptibility to active tuberculosis, evolution of cytokine and chemokine responses are crucial for the disease progression and establishment. Cytokines modulate the activities of target cells and initiate immune response while chemokines are important in the recruitment of immune cells to the site of infection. Polymorphisms in genes encoding for cytokines and their receptors can have a broad effect on killing mycobacteria, which reside and multiply within the macrophages. The role of interferon gamma (IFN-γ) is to activate macrophages to kill intracellular organisms. Single nucleotide polymorphisms (SNPs) in key cytokine genes may affect the functionality of IFN-γ and may result in high and low producer phenotypes. A number of SNPs have been identified in the IFN-γ and IFN-γ modulating genes that may predispose to mycobacterial diseases. However, the relevance of polymorphisms within these genes to the common phenotype of TB remains unclear. The frequency distributions of cytokine SNPs in various populations have been shown to be highly variable and this may be due to evolutionary pressures in different populations. Therefore, the aim of the current study was to investigate the functional gene polymorphisms in IFN-γ (+874 T→A), IFN-γ receptor 1 (IFN-γR1) (-273 to -741) and in IFN-γ modulating cytokines and chemokines such as interleukin 10 (IL-10) (-1082 A→G), tumor necrosis factor alpha (TNF-α) (-308 G→A), interleukin 6 (IL-6) (-174 G→C) and C-C chemokine ligand 2 (CCL-2) (-2518 A→G) to establish the baseline frequencies and to investigate their influence on TB disease susceptibility and severity in indigenous population. Moreover, chemokine CCL-2 protein levels were also assessed on a subset of samples. When cytokine genotype frequencies were analysed in healthy individuals, Pakistani population seems to have a higher proportion of alleles which were associated with high IFN-γ (T), high IL-10 (A), low TNF-α (G), high IL-6 (G) and low CCL-2 (A) phenotypes as reported from other Asian populations compared to Caucasian and African populations. This underlines the importance of a ‘local’ reference population when evaluating the clinical relevance of cytokine gene polymorphisms. In relation to TB, the IFN-γ T allele was found to be higher in pulmonary TB (PTB) patients which was restricted to pulmonary minimal and moderate TB groups and increases the odds of developing pulmonary TB by 2-3 folds. The TT genotype was also found to be associated with the first intronic CA11 repeats in moderate pulmonary TB group while AA was found to be associated with CA13 repeats in extrapulmonary disseminated TB (DTB) disease. Two novel SNPs in IFN-γR1 promoter region at positions -255 (C→T) and -129 (G→A) were found in association with pulmonary advanced (PAD) and extrapulmonary disseminated TB patients respectively, which suggest the association of these SNPs with TB disease severity. The IFN-γ modulating cytokine SNPs were also found in association with differing susceptibility and severity of TB such as IL-10 SNP (-1082) Ahigh allele with protection in pulmonary advanced and extrapulmonary TB disease, TNF-α SNP (-308) Ahigh allele with susceptibility to extrapulmonary TB disease and IL-6 SNP (-174) Clow allele with protection in pulmonary TB disease. Investigation of CCL-2 genotype-phenotype relation showed that CCL-2 GG genotype and higher CCL-2 levels may play a role in TB disease localization. interactions, the combinations of IFN-γ TT high In terms of mutiloci or IFN-γ AAlow alleles with IL-6 GGhigh allele were the most significant in increasing the odds of developing TB disease severity which is in line with the reported function of IL-6 as a part of the Th2 network. Our results suggest that combinations of key cytokine genotypes provide more meaningful associations of polymorphisms with TB disease susceptibility and severity. This study also provides useful information with respect to genetic biomarkers associated with disease susceptibility and severity in TB. Such information in the future can help National TB control programs for the identification of high risk groups in TB.