A 802.11 MAC protocol adaptation for Quantum communications C. M. Arizmendi † 1 J. P. Barrang´ u †2 O. G. Zabaleta †3 †University of Mar del Plata, Faculty of Engineering, Mar del Plata, Argentina 1 arizmend@fi.mdp.edu.ar, 2 jpbarrangu@fi.mdp.edu.ar, 3 gzabaleta@fi.mdp.edu.ar Abstract— In this work, a novel medium ac- cess control method for classical and quantum communications purposes is proposed. Near fu- ture quantum communications promise secure ways to send valuable information, therefore quantum-device network and quantum medium access control methods which avoids informa- tion loss will be necessary. On the other hand, future classical wireless communication systems aim at very high data rates, neverthe- less excessive colliding transmissions, especially in congested situation is still a problem, so de- signing a suitable MAC protocol is critical to fully take advantage of the benefit of high speed transmission. Quantum parallelism and quan- tum multipartite entanglement are exploited to design a MAC sublayer which provides the de- vices a fair and efficient access to the channel. Keywords— Quantum communications, MAC 1. Introduction Quantum computation and information processing are rapidly evolving fields of physical science. Their prac- tical importance arise from the exponential speedup in computation of certain algorithmic tasks over classical computation [5]. In a world of security-conscious infor- mation transmission, the possibility of sending hidden information in quantum states of electrons or photons would be highly desirable. A quantum communica- tion network can be set to many uses: it can transmit classical information, private classical information, or quantum information. Independently of the technol- ogy used to built quantum transmission networking, quantum channel access protocols will be necessary. The main quantum computing drawback is quantum decoherence. The coherence state, fundamental to a quantum computers operation, it is destroyed when it is affected by the environment. As a consequence, the physical requirements of manipulating a system on quantum scale are considerable, touching on the realms of superconductor, nanotechnology, and quan- tum electronics, as well as others. Despite consider- able advances in quantum technology [6, 9, 18] make us think that quantum computing horizons are not so far. Generally, wireless systems do not have a common goal and do not cooperate with each other, with every device seeking its own “benefit”. Telecommunication systems designed to provide services for more than one subscriber has to cope with the problem of medium ac- cess control (MAC), which regulates how to share the common medium (channel) among users. The most widely used standard is 802.11 produced by the In- stitute of Electrical and Electronic Engineers (IEEE). This is a standard defining all aspects of Radio Fre- quency Wireless networking. The main goal is to avoid having stations transmitting at the same time, which results in collisions and corresponding retransmissions. Because of hidden and exposed station problems, it does not use CSMA/CD (Carrier Sense Multiple Access with Collision Detection) protocol as ether- net communications does. Instead, Wireless LANs (WLANs), as standardized in IEEE 802.11, employ CSMA/CA (CSMA with Collision Avoidance) offer- ing the advantage of improved access control, which serves to reduce collisions and, thereby, improve the overall performance of the network. In order to en- sure that only one radio device is transmitting on half- duplex medium, the standard supports two operating methods, DCF (Distributed Coordination Function) and PCF (Point Coordination Function). DCF is the fundamental access method of 802.11 communications and is widely used in most simula- tions for ad hoc network research. Ad hoc networks are defined by the manner in which the network nodes are organized to provide pathways for data to be routed from the user to and from the desired destination. In other words, nodes sense the medium and transmit when the medium is idle. Flexibility, independence from central network administration, scalability, low cost, among others advantages, have made this type of networks be extensively studied in recent years. On the other hand, for base station (BS) oriented network- ing, where access is centralized by a coordinator de- vice or Access Point (AP) which enables other devices to use the medium, PCF is used. BS-oriented net- works are more reliable and have better performance than Ad hoc ones [20]. Both, the BS-oriented net- works (also called infrastructure networks) and ad hoc networks have some drawbacks. An infrastructure net- work takes a bit more work than setting up an ad-hoc network. Infrastructure networks cut the data transfer