5 research outputs found
Resilient Wireless Sensor Networks Using Topology Control: A Review
Wireless sensor networks (WSNs) may be deployed in failure-prone environments, and WSNs nodes easily fail due to unreliable wireless connections, malicious attacks and resource-constrained features. Nevertheless, if WSNs can tolerate at most losing k â 1 nodes while the rest of nodes remain connected, the network is called k â connected. k is one of the most important indicators for WSNsâ self-healing capability. Following a WSN design flow, this paper surveys resilience issues from the topology control and multi-path routing point of view. This paper provides a discussion on transmission and failure models, which have an important impact on research results. Afterwards, this paper reviews theoretical results and representative topology control approaches to guarantee WSNs to be k â connected at three different network deployment stages: pre-deployment, post-deployment and re-deployment. Multi-path routing protocols are discussed, and many NP-complete or NP-hard problems regarding topology control are identified. The challenging open issues are discussed at the end. This paper can serve as a guideline to design resilient WSNs
Multipath routing and QoS provisioning in mobile ad hoc networks
PhDA Mobile Ad Hoc Networks (MANET) is a collection of mobile nodes that can
communicate with each other using multihop wireless links without utilizing any
fixed based-station infrastructure and centralized management. Each mobile node
in the network acts as both a host generating flows or being destination of flows
and a router forwarding flows directed to other nodes.
Future applications of MANETs are expected to be based on all-IP
architecture and be capable of carrying multitude real-time multimedia
applications such as voice and video as well as data. It is very necessary for
MANETs to have an efficient routing and quality of service (QoS) mechanism to
support diverse applications.
This thesis proposes an on-demand Node-Disjoint Multipath Routing protocol
(NDMR) with low broadcast redundancy. Multipath routing allows the
establishment of multiple paths between a single source and single destination
node. It is also beneficial to avoid traffic congestion and frequent link breaks in
communication because of the mobility of nodes. The important components of
the protocol, such as path accumulation, decreasing routing overhead and
selecting node-disjoint paths, are explained. Because the new protocol
significantly reduces the total number of Route Request packets, this results in an
increased delivery ratio, smaller end-to-end delays for data packets, lower control
overhead and fewer collisions of packets.
Although NDMR provides node-disjoint multipath routing with low route
overhead in MANETs, it is only a best-effort routing approach, which is not
enough to support QoS. DiffServ is a standard approach for a more scalable way
to achieve QoS in any IP network and could potentially be used to provide QoS
in MANETs because it minimises the need for signalling. However, one of the
biggest drawbacks of DiffServ is that the QoS provisioning is separate from the
routing process. This thesis presents a Multipath QoS Routing protocol for
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supporting DiffServ (MQRD), which combines the advantages of NDMR and
DiffServ. The protocol can classify network traffic into different priority levels
and apply priority scheduling and queuing management mechanisms to obtain
QoS guarantees
Content dissemination in participatory delay tolerant networks
As experience with the Web 2.0 has demonstrated, users have evolved from being only consumers
of digital content to producers. Powerful handheld devices have further pushed this
trend, enabling users to consume rich media (for example, through high resolution displays), as
well as create it on the go by means of peripherals such as built-in cameras.
As a result, there is an enormous amount of user-generated content, most of which is
relevant only within local communities. For example, students advertising events taking place
around campus. For such scenarios, where producers and consumers of content belong to the
same local community, networks spontaneously formed on top of colocated user devices can
offer a valid platform for sharing and disseminating content.
Recently, there has been much research in the field of content dissemination in mobile
networks, most of which exploits user mobility prediction in order to deliver messages from
the producer to the consumer, via spontaneously formed Delay Tolerant Networks (DTNs).
Common to most protocols is the assumption that users are willing to participate in the content
distribution network; however, because of the energy restrictions of handheld devices, usersâ
participation cannot be taken for granted.
In this thesis, we design content dissemination protocols that leverage information about
user mobility, as well as interest, in order to deliver content, while avoiding overwhelming noninterested
users. We explicitly reason about battery consumption of mobile devices to model
participation, and achieve fairness in terms of workload distribution. We introduce a dynamic
priority scheduling framework, which enables the network to allocate the scarce energy resources
available to support the delivery of the most desired messages. We evaluate this work
extensively by means of simulation on a variety of real mobility traces and social networks, and
draw a comparative evaluation with the major related works in the field