Editing Carrier-sense multiple access (section)

==Protocol modifications==
When broadcasting over vehicular ad hoc networks, the original 1-persistence and p-persistence strategies often cause the [[broadcast storm]] problem.{{citation needed|date=November 2018}} To improve performance, engineers developed three modified techniques: weighted p-persistence, slotted 1-persistence, and slotted p-persistence.<ref>
Najafzadeh; Ithnin; Karimi.
"An Analytical Model for Sparse and Dense Vehicular Ad hoc Networks".
[https://books.google.com/books?id=d8AaeYeLVK8C "Advances in Computer Science and Information Technology"]:
First International Conference on Computer Science and Information Technology, CCSIT 2011.
p. 211.
</ref><ref>
Choi et al.:
[https://www.researchgate.net/publication/269591370_Robust_broadcast_scheme_regardless_of_vehicle_distribution_in_vehicular_ad_hoc_networks "Robust broadcast scheme regardless of vehicle distribution in vehicular ad hoc networks"].
EURASIP Journal on Wireless Communications and Networking 2014 2014:133.
{{doi|10.1186/1687-1499-2014-133}}
[accessed Sep 2, 2017].
</ref>

===Carrier-sense multiple access with collision detection===
{{Main|CSMA/CD}}
[[CSMA/CD]] is used to improve CSMA performance by terminating transmission as soon as a collision is detected, thus shortening the time required before a retry can be attempted. CSMA/CD is used by [[Ethernet]].

=== Carrier-sense multiple access with collision avoidance ===
{{Main|CSMA/CA}}
In [[CSMA/CA]] collision avoidance is used to improve the performance of CSMA. If the transmission medium is sensed busy before transmission, then the transmission is deferred for a random interval. This random interval reduces the likelihood that two or more nodes waiting to transmit will simultaneously begin transmission upon termination of the detected transmission, thus reducing the incidence of collision. CSMA/CA is used by [[Wi-Fi]].

===CSMA with Collision Resolution===
CSMA/CR uses priorities in the frame header to avoid collisions. It is used in the [[Controller Area Network]].

===Virtual time CSMA===
VTCSMA is designed to avoid collision generated by nodes transmitting signals simultaneously, used mostly in hard [[Real-time computing|real-time systems]]. It uses two clocks to prioritize messages based on their deadline.<ref>{{cite book |last1=Krishna |first1=C. M. |last2=Shin |first2=K. G. |date=1997 |title=Real-Time Systems |publisher=McGraw-Hill Higher Education |page=240 |isbn=978-0-07-070115-1 }}</ref>