Editing Wireless network (section)

=== Capacity ===

==== Channel ====
{{Main article|Channel capacity#Channel capacity in wireless communications|l1=Channel capacity in wireless communications}}
[[File:MIMO SIMO MISO SISO explanation without confusion.svg|thumb|upright=0.9|Understanding of SISO, SIMO, MISO and [[MIMO]]. Using multiple antennas and transmitting in different frequency channels can reduce fading, and can greatly increase the system capacity.]]

[[Shannon's theorem]] can describe the maximum data rate of any single wireless link, which relates to the bandwidth in hertz and to the noise on the channel.

One can greatly increase channel capacity by using [[MIMO]] techniques, where multiple aerials or multiple frequencies can exploit multiple paths to the receiver to achieve much higher throughput – by a factor of the product of the frequency and aerial diversity at each end.

Under Linux, the Central Regulatory Domain Agent (CRDA) controls the setting of channels.<ref>{{cite conference
| url = https://books.google.com/books?id=yLOWkHIhr6UC
| title = Towards Maximising Wireless Testbed Utilization Using Spectrum Slicing
| author = Anadiotis, Angelos-Christos| year = 2010
| conference = 6th International ICST Conference, TridentCom 2010, Berlin, Germany, May 18–20, 2010
|editor1=Thomas Magedanz |editor2=Athanasius Gavras |editor3=Huu Thanh Nguyen |editor4=Jeffrey S. Chase | volume = 46
| book-title = Testbeds and Research Infrastructures, Development of Networks and Communities: 6th International ICST Conference, TridentCom 2010, Berlin, Germany, May 18–20, 2010, Revised Selected Papers
| publisher = Springer Science & Business Media
| access-date = 2015-07-19
| quote = […] Central Regulatory Domain Agent (CRDA) […] controls the channels to be set on the system, based on the regulations of each country.
| page = 302
| isbn = 9783642178504
|display-authors=etal}}</ref>

==== Network ====
The total network bandwidth depends on how dispersive the medium is (more dispersive medium generally has better total bandwidth because it minimises interference), how many frequencies are available, how noisy those frequencies are, how many aerials are used and whether a directional antenna is in use, whether nodes employ power control and so on.

Cellular wireless networks generally have good capacity, due to their use of directional aerials, and their ability to reuse radio channels in non-adjacent cells. Additionally, cells can be made very small using low power transmitters this is used in cities to give network capacity that scales linearly with population density.<ref name="Zander" />