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| Techniques | Approaches | Advantages | Disadvantages | General |
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Centralized | Hierarchical Networks | (i) A device is responsible for the total control.
(ii) Only specific nodes send information.
(iii) Nodes perform tasks according to their location in the network.
(iv) There are a simple access and control of the network. | (i) Energy consumption is highly consumed.
(ii) Some nodes do not have any assigned task.
(iii) The complete connectivity of nodes is not ensured.
(iv) The network can be flooding of the messages.
(v) Scalability is not considered. |
(i) Advantages
(a) A device controls the entire environment.
(b) Only some nodes forward their information until sink nodes.
(c) Nodes are deployed on strategic places.
(d) The exact position where an event has been detected is known.
(e) Loss of messages is not important.
(f) Usually, a GPS or triangulation technique is used for every node position.
(ii) Drawbacks
(a) Energy consumption is highly consumed.
(b) The connectivity in all nodes is not ensured.
(c) There is flooding of messages.
(d) Reconfiguration affects the entire network.
(e) Scalability is difficult.
(f) All nodes need to know the network.
(g) Memory can be insufficient.
(h) Usually, the nodes are considered with unlimited capabilities. |
| Static Networks | (i) The nodes position and the entire environment is known since the beginning.
(ii) All nodes have assigned tasks.
(iii) These networks can be used with mobile nodes in an easy way.
(iv) Nodes are deployed on strategic places.
| (i) Energy is consumed in all nodes.
(ii) Energy consumption is highly consumed.
(iii) Usually, reconfiguration is not considered.
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| Defined Operational Networks | (i) Only nodes with a defined operation spent their energy.
(ii) Always are directed by a target.
(iii) Nodes usually have predefined movements. | (i) Frequently, the connectivity cannot be entirely ensured.
(ii) If a node inside the detected event zone dies, the information is lost. |
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| Distributed | Hierarchical | (i) The information is local (neighbors nodes).
(ii) The broadcast messages are forwarded into a transmission range.
(iii) A multihop strategy is used, which allows a better performance.
(iv) Reconfiguration is usually made only in the affected part.
| (i) Only nodes with a defined operation spent their energy; it means that the lifetime of those nodes can be shorter than others’.
(ii) Always are directed by a target.
(iii) Nodes usually have predefined movements.
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(i) Advantages
(a) The information is local.
(b) Nodes are autonomous.
(c) Self-organization can be implemented.
(d) Scalability is considered.
(e) Different paths can be found for the transmission of a message.
(f) The lifetime is extended.
(g) Reconfiguration is done only in the affected part.
(h) Adding/eliminating nodes is easy.
(i) Multihop and nature behavior strategies are an efficient tool to solve some problems.
(ii) Drawbacks
(a) Messages need to have a TTL or a defined number of hops for their transmissions.
(b) These networks are more likely to break.
(c) Loss of messages can affect the behavior of the network.
(d) The network cannot ensure the connectivity of all nodes.
(e) The bottleneck problems can be formed.
(f) The base station, sinks, or leader nodes deplete their energy faster than the rest of the nodes. |
Application
(i) Routing | (i) The information is local (neighbors nodes).
(ii) The broadcast messages are forwarded into a transmission range.
(iii) The best routes can be chosen using probability or nature behavior strategies (ants, birds, etc.).
| (i) The chosen routes cannot be the best at least; they use proper metrics.
(ii) Energy can be wasted finding available paths.
(iii) Execution times are not considered.
(iv) Bottleneck problem can occur.
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| (ii) Event detection | (i) It is used for saving energy in the network.
(ii) Nodes can change their role with neighbor nodes.
(iii) The path to get the sink node is built taking into account metrics (link quality, weight, distance, hops, etc.).
| (i) Frequently, losses of messages are not taken into account.
(ii) Sometimes, a lot of sink nodes are used to collect data.
(iii) Nodes cannot have assigned tasks.
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Topology
(i) Tree | (i) Transmission stage energy wear is lower (end-to-end).
(ii) Reconnection is simple.
(iii) There are no significance losses of messages.
(iv) There is easy implementation.
| (i) If a parent node dies, reconfiguration needs to be done, or the communication is broken.
(ii) The transmission is unidirectional.
(iii) Energy consumption is high during backbone formation.
(iv) A Bottleneck problem can be formed.
(v) The branches can be unbalanced. |
| (ii) Cluster | (i) A leader controls a determined number of nodes and the activities inside a group.
(ii) Energy consumption is distributed more uniformly.
(iii) Reconfiguration is simple.
(iv) Nodes know their neighborhood.
(v) Nodes activities are defined by roles or their position in the cluster.
(vi) A node can join an existent cluster or create a new one.
| (i) Leader nodes can deploy their energy faster.
(ii) Redundant links can affect the performance of the network.
(iii) Cycles waste energy.
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| (iii) Cluster tree | (i) Redundant links on the clusters can be deleted.
(ii) Transmission is one-hop.
(iii) Activities are determinate by the role of the node.
(iv) Communication is through leader nodes.
(v) Cycles are eliminated.
(vi) Reconfiguration is simple.
(vii) Information can be forwarded by more than one path. | (i) A bottleneck problem can arise without a good configuration.
(ii) No information redundancy is a drawback by itself but can be treated with a good heuristic.
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