Wireless sensor network always use unlicensed ISM band frequencies. Cognitive radio technique has advantages when license and unlicensed band are both deployed in network. So is using cognitive radio suitable for WSN?
Cognitive wireless sensor networks is a a type of sensor networks where the sensors have cognitive abilities. they can change and adapt their communication parameters in accordance to the change to the surrounding environment and this is major difference with the conventional wireless sensor networks. They key enabling for this technology is the spectrum sensing they can use the vacant frequencies to their transmissions in underlay or overlay methods.
Cognitive wireless sensor networks is a a type of sensor networks where the sensors have cognitive abilities. they can change and adapt their communication parameters in accordance to the change to the surrounding environment and this is major difference with the conventional wireless sensor networks. They key enabling for this technology is the spectrum sensing they can use the vacant frequencies to their transmissions in underlay or overlay methods.
i think cognitive radio is useful on WSN in some case
suppose our sensing phenomenon events randomly in time domain and our sensing method is event triger
event happen in some places of sensing field which have different value of importance. we can set the important location and its sensors as primary and other location's sensors and secondary.
in the procedure of sensing and transmission of data , secondary nodes which have less valuable data distinguish spectrum occupation and if it is not occupied by primaries they send their data on channel
the major difference between traditional WSN and CWSN is in the communication channels among the nodes. As my colleages said the communication channels of CWSN are not fixed, instead the nodes may utilize the vacant channels (Interweave or Overlay) and/or the occupied channels that may be able to transmit in low power power (Underlay). The strategy depends upon: 1) Spectrum bands availability, e.g. the transmission on 600 MHz is not like transmitting on 6 GHz; and 2) The distance among the nodes.
Cognitive wireless sensors Network (CWSN) in wireless communication is the technology which provide efficient spectrum utilization which enables opportunistic access to the spectrum. The main potential advantages introduced by cognitive radio are improving spectrum utilization and increasing communication quality.
These appealing features match the unique requirements and challenges of resource-constrained multi-hop wireless sensor networks (WSN). Furthermore, dynamic spectrum access stands as very promising and spectrum-efficient communication paradigm for WSN due to its event-driven communication nature, which generally yields bursty traffic depending on the event characteristics. In addition, opportunistic spectrum access may also help eliminate collision and excessive contention delay incurred by dense deployment of sensor nodes.
There are many advantages. However, all of them comes at the higher cost of sensors. They should be equipped with spectrum sensing capabilities. In other case spectrum pooling mechanism can be used. For readings:
1.
A Survey on Radio Resource Allocation in Cognitive Radio Sensor Networks, 2015
2. Cognitive Radio Sensor Networks, IEEE Networks, 2009
It may a little late to answer this. However, you need to understand that several of the advantages of a Cognitive Radio based Wireless Sensor Network, depends on the "Operating Spectrum" used for the cognitive radio based sensor nodes. For example, if TV spectrum is used as the operating spectrum by sensor network nodes, such nodes would have a higher transmission range because the UHF and VHF like bands allow transmission to penetrate through walls. This is known as Wide band Sensing. Now since it has a higher transmission range, you need very few hops to reach the gateway node. Few required hops would mean, lesser synchronization errors and the required density of nodes would be less. Penetration through walls make such a sensor network very reliable in indoor settings to outdoor gateways. These advantages are not there if you used iSM bands. As you see the entire advantage is that you could switch to certain operating spectrum whose characteristics are suited to your GOAL of the network. However, enough operating spectrum may not be available in large cities. In such cases, GSM or Radar Whitespaces could be used.