Sharif Digital Repository

Heterogeneity is one of the challenges in the current NoC (Network-on-Chip) domain which oblige designers to consider less regular topologies to provide the best cost-performance trade-off while minimizing resource and power consumption and providing the maximum flexibility. Irregular mesh is a topology which combines the benefits of regularity and advantage of irregularity. Another important issue in any NoC is the selection of routing algorithm which provides the best performance. Routing algorithms especially those coupled with wormhole switching should deal with deadlock occurrences. Deadlock detection and recovery-based routing schemes for this type of switching gained attraction since... 

The increasing complexity of integrated circuits drives the research of new on chip interconnection architectures. Network On Chip (NoCs) are a candidate architecture to be used in future systems, due to its increased performance, reusability and scalability. A NoC is a set of interconnected switches, with IP cores connected to these switches. Different routing algorithms have been proposed for NoCs such as XY deterministic algorithm, and WF (West First), NL (North Last) and NF (Negative First) as partially adaptive algorithms. OE (Odd Even) is not based on adding virtual channels to network topologies. Unlike previous methods, which rely on prohibiting certain turns in order to achieve... 

A geometric network is a weighted undirected graph whose vertices are points in the plane and edge weights are equal to the Euclidean distance of its endpoints. Routing is one of the important problems in graph theory and if the underlying graph is a geometric network,it has applications in different fields including transportation, communication networks and robotics. In many applications the graph data is not accessible or finding the optimal path is costly. Therefore local routing is used. In local routing the goal is that at each vertex,the routing must be done only given the neighbours of the current vertex, the origin and the destination of the route. Geometric spanner is a subgraph of... 

Wireless Sensor Network (WSN) is a set of cheap wireless sensors that can collect, process and send environment’s data. WSN nodes are battery powered, therefore energy management is a key factor for long live network. One way to prolong lifetime of network is to utilize routing protocols to manage energy consumption. To have an energy efficient protocol, we can apply ZigBee protocols. ZiBgee standard is originated from IEEE802.15.4 standard that is defined for personal wireless networks with low bit rate. Now there are many different routing methods that are defined for ZigBee networks that have applications in different circumstances. These methods usually have been proposed in the network... 

In this thesis, we propose a QoS-aware routing algorithm for multimedia streaming that uses cross-layer information (application layer and physical layer) in Wireless Multimedia Sensor Networks (WMSN). Our goal is to use cross-layer information to route video packets efficiently and deliver a higher quality video in streaming applications. Our QoS-Aware Multi-Path Selection (QAMPS) method is based on multi-path multi-priority selection algorithm that uses Two-Phase geographic Greedy Forwarding (TPGF) as a routing algorithm. The proposed method guarantees QoS by splitting video streams into I-frames, P-frames and B-frames in the application layer and passes them to the network layer for... 

This project presents a routing algorithm to cope with the dynamic traffic pattern of network-on-chip (NoC) architectures aiming to distribute the on-chip traffic evenly across the network. In this algorithm, instead of relying solely on local congestion information, the routes are determined based on the global information about on-chip traffic. This is achieved by employing a light-weight and efficient control network which monitors the on-chip traffic and collects the required information for determining the appropriate path between any pairs of communicating nodes in such a way that the congestion is avoided and the NoC load is balanced. Our experiments show that the proposed method... 

Three-dimensional network-on-chip (3D NoC), the combination of NoC and die-stacking 3D IC technology, is motivated to achieve lower latency, lower power consumption, and higher network bandwidth. 3D NoCs reduce length of communication link and transmition delay by die stacking. However, the length of heat conduction path and power density per unit area increase as more dies are stacked vertically. High temperature results in longer propagation delay and increases the leakage power. If heat production in the chip is not managed, low cooling rate for these layers is a threat for the chip performance and reliability. To solve the thermal problems, thermal management schemes were proposed in the... 

Wireless Sensor Networks (WSNs) consist of sensor nodes that are connected to each other and are widely used in many applications to acquire and process information. WSN nodes are battery powered, therefore energy management is a key factor for long live network. Node radio transceiver unit uses the most part of energy resource of the node and as a result limits the network lifetime. One way to prolong lifetime of network is to utilize routing protocols to manage energy consumption. To have an energy efficient protocol, we can apply cluster organization on the network, where sensor nodes are partitioned into groups called cluster. Then, the whole cluster data is sent through Cluster Head... 

Cross layer resource allocation is necessary for efficient use of resource sina data communication network.In such a design, in addition tomaximizing the throughput of the network, Quality of Service constraints shouldbe considered for each session. End-to-end delayis one of the most important QoS parameters, which should be considered especially for multimedia applications.In this dissertation, we develop a jointly optimal service scheduling, routing & flow control algorithm for a wired multi-hop network which provides intended upper bounds on sessions' maximum delay. In order to incorporate worst-case delay constraint in cross layer formulation, we first attain an upper bound for the end... 

Delay Tolerant Networks (DTNs) are sparse networks in which intermittent connectivity happens due to energy shortage or high mobility and long latency is unavoidable.These networks have a wide range of applications in our daily life such as internet of moving things. In delay tolerant networks, finding an end to end path between source and destination is almost impossible. Therefore, routing can’t be done based on finding an end to end path but it has to be done based on hop by hop sessions. In this thesis, we aim to represent an efficient routing algorithm for delay tolerant networks that can improve delivery probability, delivery cost and delivery latency.Our proposed routing algorithm is... 

High-definition video streaming, multimedia file sharing, cloud computing, mobile networks and online gaming, all together, will increase the network traffic enormously every year.Long-haul optical fiber networks form the backbone of the Internet and scaling to higher throughput and lower cost per bit is essential to ensure continued growth of information technologies. For four decades, optical networks have exploited significant progress in physical technologies, including low-loss single-mode fibers (SMFs), high-performance lasers and modulators, and low-noise optical amplifiers. In parallel, communication methods have evolved to multiplex information in various physical dimensions in... 

Opportunistic delay tolerance networks are widely used networks that do not require infrastructure. Many routing algorithms have been proposed for these networks in which nodes need to compare their metrics (such as visit frequency, node geographical location, etc.)Therefore, routing in these networks has a high security risk and the possibility of violating privacy. There are many ways to protect privacy, but these methods have limitations: some are limited to vehicles and some are limited to social networks and node communities. Also, more general methods require a lot of complexity, including processing time, storage resources, and key management.In this study, we propose a method with... 

UAV routing algorithms, correct modeling of battery life is very important, which can be done by dynamically integrating the UAV with routing. A drone must visit a set of targets, although after reaching a predetermined distance from the target, the drone must adjust its flight mode for loading (delivery) and after delivery must complete the escape maneuver. And prepare for the next delivery. Routing and optimization factors should be combined to ensure the safety of the vehicle and the feasibility (route feasibility). Research and studies that have been done in this field, have solved the problems by considering the exact time and also less attention to the energy limitations of these... 

Network-on-Chip (NoC) as a promising design approach for on-chip interconnect fabrics could overcome the energy as well as synchronization challenges of the conventional interconnects in the gigascale System-on-Chips (SoC). The advantage of communication performance of traditional wired NoC will no longer be continued by the future technology scaling. Packets that travel between distant nodes of a large scale wired on-chip network significantly suffer from energy dissipation and latency due to the routing overhead at each hop. According to the ITRS annual report, the RFCMOS characteristics will be steadily improved by technology scaling. As the operating frequency of RF devices increases,... 

Combining the concept of Network-on-Chip (NoC) with three dimensional integrated circuits technology on 3D NoC enables reduction of propagation delay, interconnect power consumption, and die area, as well as increase in system operational bandwidth. Nevertheless, reducing the feature size of semiconductor technologies has raised certain aging mechanisms, like Negative Bias Temperature Instability (NBTI) and Electromigration, as the main reasons for reduction in reliability and lifetime of NoCs. Reduction in die area results in an increase in power density of the chip, which exacerbates temperature-related concerns of 3D NoCs compared to 2D NoCs. Thus, the aging mechanisms that are directly...