Future Evolution of CSMA Protocols for the IEEE 802.11 Standard

In this paper a candidate protocol to replace the prevalent CSMA/CA medium access control in Wireless Local Area Networks is presented. The proposed protocol can achieve higher throughput than CSMA/CA, while maintaining fairness, and without additional implementation complexity. Under certain circumstances, it is able to reach and maintain collision-free operation, even when the number of contenders is variable and potentially large. It is backward compatible, allowing for new and legacy stations to coexist without degrading one another's performance, a property that can make the adoption process by future versions of the standard smooth and inexpensive.Comment: This paper has been accepted in the Second IEEE ICC Workshop 2013 on Telecommunication Standards: From Research to Standard

Implementation and Experimental Evaluation of a Collision-Free MAC Protocol for WLANs

Collisions are a main cause of throughput degradation in Wireless LANs. The current contention mechanism for these networks is based on a random backoff strategy to avoid collisions with other transmitters. Even though it can reduce the probability of collisions, the random backoff prevents users from achieving Collision-Free schedules, where the channel would be used more efficiently. Modifying the contention mechanism by waiting for a deterministic timer after successful transmissions, users would be able to construct a Collision-Free schedule among successful contenders. This work shows the experimental results of a Collision-Free MAC (CF-MAC) protocol for WLANs using commercial hardware and open firmware for wireless network cards which is able to support many users. Testbed results show that the proposed CF-MAC protocol leads to a better distribution of the available bandwidth among users, higher throughput and lower losses than the unmodified WLANs clients using a legacy firmware.Comment: This paper was submitted to the IEEE International Conference on Communications 2015 and it is waiting for approva

Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

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Collision-free WLANs: from concepts to working protocols

Using a deterministic backoff after successful transmissions as a distributed contention mechanism for access to the channel can draw benefits from scheduled operation, like the elimination of simultaneous transmissions, and Quality of Service (QoS). Carrier Sense Multiple Access with Enhanced Collision Avoidance (CSMA/ECA) is a compatible protocol that implements such technique, outperforming the current Medium Access Control (MAC) protocol in WiFi. This work describes several extensions to CSMA/ECA that allows it to support many more contenders in a collision-free schedule in very diverse scenarios, while evenly distributing the available throughput among users. Further, it introduces CSMA/ECA with multiple queues for providing traffic differentiation. Lastly, it presents progressive evolutions of an off-the-shelf hardware implementation of CSMA/ECA using open source tools.L'ús d'un backoff determinista després de transmissions exitoses com a mecanisme de contenció distribuït per l'accés al canal pot extreure beneficis de l'operació planificada, com l'eliminació de les transmissions simultànies, i Qualitat de Servei (QoS). Carrier Sense Multiple Access with Enhanced Collision Avoidance (CSMA/ECA) és un protocol compatible que implementa aquesta tècnica, superant l'actual protocol Medium Access Control (MAC) en Wi-Fi. Aquest treball descriu diverses extensions de CSMA/CA que li permet suportar molts més contendents sense col·lisions en molt diversos escenaris, mentre distribueix equitativament el throughput entre els usuaris. A més, s'introdueix CSMA / ECA amb múltiples cues per proporcionar diferenciació de trànsit. Finalment, es presenten evolucions progressives d'una implementació de maquinari off-the-shelf de CSMA / ECA utilitzant eines de codi obert