A Markovian model for satellite integrated cognitive and D2D HetNets

Next-generation wireless systems are expected to provide bandwidth-hungry services in a cost-efficient and ubiquitous manner. D2D communications, spectrum sharing and heterogeneous network architectures (HetNets) are touted as crucial enablers to attain these goals. Moreover, the shifting characteristics of network traffic towards content consumption necessitate content-centric architectures and protocols. In this work, we propose a comprehensive analytical model for a content-oriented heterogeneous wireless network with cognitive capability. We model our HetNet architecture with a Continuous Time Markov Chain (CTMC) and characterize the trade-off between energy efficiency and system goodput. We elaborate on novel elements in our model, namely the integration of universal source concept (modeling the content retrieval operation from external networks), caching and overlaying in D2D mode. Besides, our investigation on network mode selection provides further insight on how resource allocation and performance are intertwined

Bandwidth Efficient Livestreaming in Mobile Wireless Networks: A Peer-to-Peer ACIDE Solution

In this paper, a media distribution model, Active Control in an Intelligent and Distributed Environment (ACIDE), and solutions are proposed for video and audio livestreaming in mobile wireless networks. A base station and a cluster formed by a number of users are the essential components. Inside a cluster, users can establish peer to peer communications. The users that are members of a cluster are considered peers. This paper addresses the problem of minimizing the bandwidth allocated to a cluster of n peers such that a continuous media play of all the peers is guaranteed. The basic idea is to send the livestream media in packages. A media package is divided into n blocks. The distribution of blocks to the peers of a cluster follows a two-phase, multi-step approach. In phase 1 each peer receives one block with the optimal size from the base station. In phase 2, peers exchange their media blocks simultaneously in a few steps. Then the media package can be reconstructed and a live media can be played continuously. Allocated bandwidth, the amount of bandwidth the base station has to allocate to this cluster in order to play live streaming media without interruptions, is a function of many parameters such as the block sizes, download and upload bandwidth values of peers. This problem is formulated as an optimization problem. A solution is proposed to find the optimal block sizes such that the allocated bandwidth is minimized. Both theoretical model and simulations show that when the number of peers is large, the optimal allocated bandwidth approaches the lower bound that is the bandwidth required for multicasting. In other words, the allocated bandwidth may be reduced n times.Comment: 8 pages, 6 figures, Conference Submissio

A Study of Effect of Architectural Design on Quality of Service of a Live Streaming Application with Multiple Endpoints over LTE Network

วิทยาศาสตรมหาบัณฑิต (วิทยาการคอมพิวเตอร์), 2565The number of streaming service providers has been increasing dramatically every year. Hence, users may prefer to publish their stream to multiple service endpoints simultaneously to increase visibility. However, most service providers prefer to monopolize their services. Hence, a study of a suitable architectural design of a streaming service that supports multiple streaming endpoints has not gained lots of attention. In this study, the effect of adopting different architectural design on developing a live streaming service over LTE network which can supports multiple streaming endpoints are investigated. Two major designs are selected which are a selective forwarding unit-based architecture, and a non-selective forwarding unit-based architecture. The results suggest that a selective forwarding unit architecture has an advantage over a non-selective forwarding unit-based architecture on keeping the overall average streaming end-to-end delay to be minimum., while a fluctuation in an end-to-end delay occurs in a non-selective forwarding unit based architecture in our experiment testbed. The results, discussions, and suggestions on future studies are given at the end of this study.จํานวนผู้ให้บริการสตรีมมิ่งเพิ่มขึ้นอย่างมากทุกปี ดังนั้นผู้ใช้บริการที่ต้องการเผยแพร่สตรีม ของตนไปยังผู้ให้บริการหลายแห่งเพื่อเพิ่มการมองเห็นจากผู้ชม อย่างไรก็ตาม ผู้ให้บริการส่วนใหญ่ ต้องการผูกขาดบริการของตน ทําให้การศึกษาการออกแบบสถาปัตยกรรมที่เหมาะสมของบริการ สตรีมมิ่งที่รองรับหลายปลายทางการสตรีมจึงไม่ได้รับความสนใจมากนัก ในการศึกษานี้จะตรวจสอบ ผลกระทบของการนําการออกแบบสถาปัตยกรรมที่แตกต่างกันมาใช้ในการพัฒนาบริการสตรีมมิ่งแบบ สดผ่านเครือข่าย Long Term Evolution(LTE) ซึ่งสามารถรองรับปลายทางการสตรีมหลายจุด การ ออกแบบที่สําคัญสองแบบซึ่งเป็นสถาปัตยกรรมแบบใช้หน่วยการส่งต่อแบบคัดเลือกและ สถาปัตยกรรมแบบไม่ใช้หน่วยการส่งต่อแบบคัดเลือก ผลลัพธ์ที่ได้แสดงให้เห็นว่าสถาปัตยกรรมแบบ ที่ใช้หน่วยการส่งต่อแบบคัดเลือกมีข้อได้เปรียบเหนือสถาปัตยกรรมที่ไม่ใช้หน่วยส่งต่อแบบคัดเลือก โดยรักษาการหน่วงเวลาการสตรีมจากต้นทางถึงปลายทางโดยเฉลี่ยน้อยกว่า ในขณะที่การหน่วงเวลา ของสถาปัตยกรรมแบบไม่ใช้หน่วยการส่งต่อแบบคัดเลือกจากต้นทางถึงปลายทางจะผันผวน ในแบบ การทดลองนี้ ผลลัพธ์ การอภิปราย และข้อเสนอแนะเกี่ยวกับการศึกษาในอนาคตท้ายการศึกษานี

Efficient Algorithms for Cache-Throughput Analysis in Cellular-D2D 5G Networks

In this paper, we propose a two-tiered segment-based Device-to-Device (S-D2D) caching approach to decrease the start up and playback delay experienced by Video-on-Demand (VoD) users in a cellular network. In the S-D2D caching approach cache space of each mobile device is divided into two cache-blocks. The first cache-block reserve for caching and delivering the beginning portion of the most popular video les and the second cache-block caches the latter portion of the requested video les ‘fully or partially’ depending on the users’ video watching behaviour and popularity of videos. In this approach before caching, video is divided and grouped in a sequence of fixed-sized fragments called segments. To control the admission to both cache-blocks and improve the system throughput, we further propose and evaluate three cache admission control algorithms. We also propose a video segment access protocol to elaborate on how to cache and share the video segments in a segmentation based D2D caching architecture. We formulate an optimisation problem and the optimal cache probability and beginning-segment size that maximise the cache-throughput probability of beginning-segments. To solve the non-convex cache-throughout maximisation problem, we derive an iterative algorithm, where the optimal solution is derived in each step. We used extensive simulations to evaluate the performance of our proposed S-D2D caching system

Efficient algorithms for cache-throughput analysis in cellular-D2D 5G networks

In this paper, we propose a two-Tiered segment-based Device-To-Device (S-D2D) caching approach to decrease the startup and playback delay experienced by Video-on-Demand (VoD) users in a cellular network. In the S-D2D caching approach cache space of each mobile device is divided into two cache-blocks. The first cache-block reserve for caching and delivering the beginning portion of the most popular video files and the second cacheblock caches the latter portion of the requested video files fully or partially depending on the users video watching behaviour and popularity of videos. In this approach before caching, video is divided and grouped in a sequence of fixed-sized fragments called segments. To control the admission to both cacheblocks and improve the system throughput, we further propose and evaluate three cache admission control algorithms. We also propose a video segment access protocol to elaborate on how to cache and share the video segments in a segmentation based D2D caching architecture.We formulate an optimisation problem and find the optimal cache probability and beginning-segment size that maximise the cache-Throughput probability of beginning-segments. To solve the non-convex cache-Throughout maximisation problem, we derive an iterative algorithm, where the optimal solution is derived in each step.We used extensive simulations to evaluate the performance of our proposed S-D2D caching system

Adaptive Resource Allocation for Statistical QoS Provisioning in Mobile Wireless Communications and Networks

Due to the highly-varying wireless channels over time, frequency, and space domains, statistical QoS provisioning, instead of deterministic QoS guarantees, has become a recognized feature in the next-generation wireless networks. In this dissertation, we study the adaptive wireless resource allocation problems for statistical QoS provisioning, such as guaranteeing the specified delay-bound violation probability, upper-bounding the average loss-rate, optimizing the average goodput/throughput, etc., in several typical types of mobile wireless networks. In the first part of this dissertation, we study the statistical QoS provisioning for mobile multicast through the adaptive resource allocations, where different multicast receivers attempt to receive the common messages from a single base-station sender over broadcast fading channels. Because of the heterogeneous fading across different multicast receivers, both instantaneously and statistically, how to design the efficient adaptive rate control and resource allocation for wireless multicast is a widely cited open problem. We first study the time-sharing based goodput-optimization problem for non-realtime multicast services. Then, to more comprehensively characterize the QoS provisioning problems for mobile multicast with diverse QoS requirements, we further integrate the statistical delay-QoS control techniques — effective capacity theory, statistical loss-rate control, and information theory to propose a QoS-driven optimization framework. Applying this framework and solving for the corresponding optimization problem, we identify the optimal tradeoff among statistical delay-QoS requirements, sustainable traffic load, and the average loss rate through the adaptive resource allocations and queue management. Furthermore, we study the adaptive resource allocation problems for multi-layer video multicast to satisfy diverse statistical delay and loss QoS requirements over different video layers. In addition, we derive the efficient adaptive erasure-correction coding scheme for the packet-level multicast, where the erasure-correction code is dynamically constructed based on multicast receivers’ packet-loss statuses, to achieve high error-control efficiency in mobile multicast networks. In the second part of this dissertation, we design the adaptive resource allocation schemes for QoS provisioning in unicast based wireless networks, with emphasis on statistical delay-QoS guarantees. First, we develop the QoS-driven time-slot and power allocation schemes for multi-user downlink transmissions (with independent messages) in cellular networks to maximize the delay-QoS-constrained sum system throughput. Second, we propose the delay-QoS-aware base-station selection schemes in distributed multiple-input-multiple-output systems. Third, we study the queueaware spectrum sensing in cognitive radio networks for statistical delay-QoS provisioning. Analyses and simulations are presented to show the advantages of our proposed schemes and the impact of delay-QoS requirements on adaptive resource allocations in various environments