Editing Wireless sensor network (section)

==Characteristics==
The main characteristics of a WSN include

* Power consumption constraints for nodes using batteries or [[energy harvesting]]. Examples of suppliers are ReVibe Energy<ref>{{cite web|url=https://revibeenergy.com|title=ReVibe Energy – Powering The Industrial IoT|website=revibeenergy.com|access-date=3 May 2018|url-status=live|archive-url=https://web.archive.org/web/20170922150745/http://revibeenergy.com/|archive-date=22 September 2017}}</ref> and Perpetuum<ref>{{cite web|url=https://perpetuum.com/|title=THE WORLD LEADER IN VIBRATION HARVESTER POWERED WIRELESS SENSING SYSTEMS|website=THE WORLD LEADER IN VIBRATION HARVESTER POWERED WIRELESS SENSING SYSTEMS|access-date=3 May 2018|url-status=live|archive-url=https://web.archive.org/web/20180413082857/https://perpetuum.com/|archive-date=13 April 2018}}</ref>
* Ability to cope with node failures ([[resilience (network)|resilience]])
* Some mobility of nodes (for highly mobile nodes see [[MWSN]]s)
* Heterogeneity of nodes
* Homogeneity of nodes
* [[Scalability]] to large scale of deployment
* Ability to withstand harsh environmental conditions
* Ease of use
*[[Cross-layer optimization]]<ref>{{Cite book |pages=1–6 |doi=10.1109/TENCON.2009.5395945 |year=2009 |last1=Saleem |first1=Kashif |last2=Fisal |first2=Norsheila |last3=Hafizah |first3=Sharifah |last4=Kamilah |first4=Sharifah |last5=Rashid |first5=Rozeha |last6=Baguda |first6=Yakubu |title=TENCON 2009 - 2009 IEEE Region 10 Conference |chapter=Cross layer based biological inspired self-organized routing protocol for wireless sensor network |isbn=978-1-4244-4546-2 |s2cid=30236796 }}</ref><ref name=Zander>{{cite book|author1=Guowang Miao|author2=Jens Zander|author3=Ki Won Sung|author4=Ben Slimane|title=Fundamentals of Mobile Data Networks|publisher=[[Cambridge University Press]]|isbn=978-1-107-14321-0|year=2016|author1-link=Guowang Miao}}</ref><ref>{{cite journal|author1=Aghdam, Shahin Mahdizadeh|author2=Khansari, Mohammad|author3=Rabiee, Hamid R|author4=Salehi, Mostafa|title=WCCP: A congestion control protocol for wireless multimedia communication in sensor networks|journal=Ad Hoc Networks|year=2014|pages=516–534|doi=10.1016/j.adhoc.2013.10.006|volume=13}}</ref>

Cross-layer is becoming an important studying area for wireless communications.<ref name=Zander/> In addition, the traditional layered approach presents three main problems:
#Traditional layered approach cannot share different information among different layers, which leads to each layer not having complete information. The traditional layered approach cannot guarantee the optimization of the entire network.
#The traditional layered approach does not have the ability to adapt to the environmental change.
#Because of the interference between the different users, access conflicts, fading, and the change of environment in the wireless sensor networks, traditional layered approach for wired networks is not applicable to wireless networks.

So the cross-layer can be used to make the optimal modulation to improve the transmission performance, such as [[Bit rate|data rate]], [[Efficient energy use|energy efficiency]], [[quality of service]] (QoS), etc.<ref name=Zander/> Sensor nodes can be imagined as small computers which are extremely basic in terms of their interfaces and their components. They usually consist of a ''processing unit'' with limited computational power and limited memory, ''sensors'' or [[Microelectromechanical systems|MEMS]] (including specific conditioning circuitry), a ''communication device'' (usually radio transceivers or alternatively [[smart dust|optical]]), and a power source usually in the form of a battery. Other possible inclusions are [[energy harvesting]] modules,<ref>{{Cite journal | last1 = Magno | first1 = M. | last2 = Boyle | first2 = D. | last3 = Brunelli | first3 = D. | last4 = O'Flynn | first4 = B. | last5 = Popovici | first5 = E. | last6 = Benini | first6 = L. | doi = 10.1109/TIE.2013.2267694 | title = Extended Wireless Monitoring Through Intelligent Hybrid Energy Supply | journal = IEEE Transactions on Industrial Electronics | volume = 61 | issue = 4 | page = 1871 | year = 2014 | s2cid = 23562384 }}</ref> secondary [[Application-specific integrated circuit|ASICs]], and possibly secondary communication interface (e.g. [[RS-232]] or [[Universal Serial Bus|USB]]).

The base stations are one or more components of the WSN with much more computational, energy and communication resources. They act as a gateway between sensor nodes and the end user as they typically forward data from the WSN on to a server. Other special components in [[routing]] based networks are routers, designed to compute, calculate and distribute the routing tables.<ref>{{cite journal|first1=A.|last1=Xenakis|first2=F.|last2=Foukalas|first3=G.|last3=Stamoulis|url=https://www.sciencedirect.com/science/article/abs/pii/S0045790616300313|title=Cross-layer energy-aware topology control through Simulated Annealing for WSNs|journal=Computers & Electrical Engineering|year=2016|volume=56|pages=576–590|doi=10.1016/j.compeleceng.2016.02.015}}</ref>