Datenbestand vom 15. Oktober 2021
Tel: 089 / 66060798
Mo - Fr, 9 - 12 Uhr
Fax: 089 / 66060799
aktualisiert am 15. Oktober 2021
978-3-8439-3234-9, Reihe Informationstechnik
Adaptive MAC-Layer Protocol Switching for PLC
145 Seiten, Dissertation Technische Universität Dresden (2017), Softcover, A5
The ongoing change from conventional electrical grids towards smart grids brings new use cases to communication technologies. These influence the selection of appropriate communication systems according to the requirements of smart grid applications. Power Line Communications (PLC) is the most native communication technology for the smart grid as it uses the same medium for energy and data transmission. In order to meet the requirements of smart grid application perfectly the corresponding PLC system should be adapted dynamically. In this thesis adaptation mechanisms at the Medium Access Control (MAC) layer are studied on the example of a G.hn PLC system.
At first, the Physical (PHY) layer of G.hn is studied. Its model is implemented in the network simulator 3 (ns-3) according to the standard. At the MAC layer two channel access schemes can be used: Time Division Multiple Access (TDMA) or Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). The CSMA/CA access scheme has numerous variations. In this thesis an adaptive version of CSMA/CA from another PLC system is analyzed in detail and improved. For the TDMA scheme the equal slot assignment is selected. It is used for symmetric traffic in uplink. The assignment of slots for scenarios with downlink traffic and for special cases with repeaters are studied as well.
It is known that two MAC access schemes under consideration have their advantages and disadvantages depending on the traffic load. Therefore, in this thesis the Adaptive Layer Switching (ALS) mechanism is proposed, which switches the MAC layer from CSMA/CA to TDMA or vice versa. The switching occurs for the whole network.
The novel ALS algorithm is described and implemented in the discrete event simulator ns-3. The operation of the networks with and without repeaters under variation of offered traffic is investigated. Three realistic network topologies are used: a small size one without repeaters, a medium size with one repeater and a large size one with three repeaters. Those are studied with User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) traffic in uplink and downlink directions. The influence of the impulsive noise is studied as well. Finally, the performance of CSMA/CA, TDMA, and ALS in terms of delay and throughput is evaluated.