378 research outputs found
Topology design and scheduling in STDMA based wireless ad hoc networks
Cataloged from PDF version of article.With current advances in technology, wireless networks are increasing in
popularity. Wireless networks allow users the freedom to travel from one
location to another without interruption of their communication activities. Ad
hoc networks, a subset of wireless networks, allow the formation of a wireless
network without the need for a base station. Since no fixed infrastructure is
involved in the communication, the nodes of ad hoc networks can communicate
with each other or can relay data to other nodes. With this flexibility, wireless ad
hoc networks have the ability to form a network anywhere, at any time, as long
as two or more wireless users are willing to communicate.
Managing ad hoc networks is a significantly more difficult task than
managing wireline networks. The network requirements should be met by
combined efforts of all the mobile nodes themselves. The nodes of ad hoc
networks often operate under severe constraints, such as limited battery power,
variable link quality and limited shared bandwidth. In this study, the topology
design issue in ad hoc wireless networks is investigated. We employ hierarchical routing where the network topology is composed of clusters interconnected via a
root node. Cluster-based topologies are suitable for military services, an
important application area for ad hoc networks. The common power control
technique (COMPOW) is used in this thesis where all nodes transmit at the same
power level. Nodes employ the spatial TDMA (STDMA) scheme in order to
access the channel. An important task is how to produce a minimum STDMA
frame length, and this problem is known to be NP complete. We develop a
heuristic algorithm for generating the minimum STDMA frame length. A new
interference model for ad hoc networks is proposed which utilizes a hypergraph
model. The relationship between the frame length, number of clusters and the
transmit power level are investigated through numerical examples using a 15-
node network.Ergin, Sadettin AlpM.S
Recent Advances in Cellular D2D Communications
Device-to-device (D2D) communications have attracted a great deal of attention from researchers in recent years. It is a promising technique for offloading local traffic from cellular base stations by allowing local devices, in physical proximity, to communicate directly with each other. Furthermore, through relaying, D2D is also a promising approach to enhancing service coverage at cell edges or in black spots. However, there are many challenges to realizing the full benefits of D2D. For one, minimizing the interference between legacy cellular and D2D users operating in underlay mode is still an active research issue. With the 5th generation (5G) communication systems expected to be the main data carrier for the Internet-of-Things (IoT) paradigm, the potential role of D2D and its scalability to support massive IoT devices and their machine-centric (as opposed to human-centric) communications need to be investigated. New challenges have also arisen from new enabling technologies for D2D communications, such as non-orthogonal multiple access (NOMA) and blockchain technologies, which call for new solutions to be proposed. This edited book presents a collection of ten chapters, including one review and nine original research works on addressing many of the aforementioned challenges and beyond
Performance and energy efficiency in wireless self-organized networks
fi=vertaisarvioitu|en=peerReviewed
Applications of Repeated Games in Wireless Networks: A Survey
A repeated game is an effective tool to model interactions and conflicts for
players aiming to achieve their objectives in a long-term basis. Contrary to
static noncooperative games that model an interaction among players in only one
period, in repeated games, interactions of players repeat for multiple periods;
and thus the players become aware of other players' past behaviors and their
future benefits, and will adapt their behavior accordingly. In wireless
networks, conflicts among wireless nodes can lead to selfish behaviors,
resulting in poor network performances and detrimental individual payoffs. In
this paper, we survey the applications of repeated games in different wireless
networks. The main goal is to demonstrate the use of repeated games to
encourage wireless nodes to cooperate, thereby improving network performances
and avoiding network disruption due to selfish behaviors. Furthermore, various
problems in wireless networks and variations of repeated game models together
with the corresponding solutions are discussed in this survey. Finally, we
outline some open issues and future research directions.Comment: 32 pages, 15 figures, 5 tables, 168 reference
- …