Modelling and Characterization of Wireless Channels in Harsh Environments
2011 (English) Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Student thesis
Abstract [en]
The increased interest of industry in wireless networking technology has led tomany recent advances in wireless LANs and PANs, and has also increased researchin new domains. Since it is vital to enable highly reliable delivery in industrial area,error control is used. It can be realized in different ways: automatic repeat request(ARQ), forward error correction (FEC) and hybrid automatic repeat-request (HARQ).In order to predict radio channel quality and improve it by the use of suitable error cor-rection technique we need to know channel characteristics. Since we experimentallyinvestigated performances of received signal strength indicator (RSSI) and packet er-ror rate (PER) of real components for 2.4 GHz radio environment, with particularattention to IEEE 802.15.4 and WirelessHART, the resulting findings can serve as thebasis of required characterization. Average RSSI and PER for each link measurementwere calculated over more than 10000 transmitted packets. In wireless communi-cations, the relative strength of the direct and scattered components of the receivedsignal, as expressed by the Rician factor K, provides an indication of link quality. Forthis reason K-factor is estimated for the best-fitted Rician model. We illustrate de-tected phenomena and correlations and provide a coarse view on channels behaviour.There is a clear evidence of unisotropic nature of our metrics. Specifically, nodeswith the same line-of-sight distance did not necessarily have similar average RSSIor PER, or, more precisely, a relationship between the attenuation of a signal and thedistance was not linear. The available evidence clearly leads to the conclusion that theattenuation is not only a function of path distance alone but also indicates complexdependency on multipath effects caused by the surrounding obstacles.
Place, publisher, year, edition, pages 2011.
Keywords [en]
RSSI, PER, Wireless communication, industry, RF power measurement, channel characteristics, IEEE 802.15.4, WirelessHART
Identifiers URN: urn:nbn:se:mdh:diva-12677 OAI: oai:DiVA.org:mdh-12677 DiVA, id: diva2:427097
Presentation
2011-06-17, 14:01 (English)
Uppsok Technology
Supervisors
Examiners
2011-08-012011-06-272011-08-01 Bibliographically approved