Investigation of RF characteristics of PropSim C2 channel emulator for the wireless LAN standard IEEE 802.11p

Abstract

A successful development of wireless systems demands requirements on product development methods and testing. The real-time measurements and performance evaluation of a wireless communication system in different development stages, enable detection of system design errors at the earliest and less expensive stage of the development. The radio channel, as the medium, linking the transmitter to the receiver has an great impact on the wireless system performance. Thus the understanding of the radio channel behavior, is a key factor in developing wireless products. The radio channel characterizations are determined through a measurement campaign and mathematically formulated as a radio channel model. A real-world performance measurement is costly, and because of the unpredictable variations in the interference and stochastic behavior of the wireless propagation channel, specifically in a time-varying system, not reproducible. This motivates the need for a radio frequency platform which reproduces real-world conditions for the wireless system performance evaluation in the laboratory environment. The channel emulator, which replaces the real-world radio channel, is a major component of this testing platform. In this thesis the channel emulator Elektrobit Propsim C2, and the methodology of channel model implementation on it is investigated. Furthermore the vehicular channel models, such as the Six Time- and Frequency-Selective Empirical Channel Models for Vehicular Wireless LANs and the ETSI ITS channel models, which were developed in 2013 [10], are studied. The ETSI ITS channel models contains five Vehicle-to-Vehicle (V2V) scenarios, whereby two of them are without availability of a LOS path. The aim of this study is to understand the channel model parameters, presented in these models, for the further implementation on the EB Propsim C2. There are two options for the implementation of the channel models on the Propsim C2, namely through the Edit sceen in the Graphical User Interface (GUI), or through generating the Impulse Responses (IRs) on the computer, storing the IR-file on the Propsim C2 and run the emulation through this IR-file. Both methods are presented and the restrictions and advantages of each method are described. As mentioned above, the real-world performance evaluation of a wireless communication system is extremely important. The major part of this thesis, is about computing the Packet Error Ratio (PER) of the Kapsch transceiver MTX-9450, which is based on standard IEEE 802.11p in Physical layer (PHY), for the ETSI ITS channel models. For this purpose a measurement plan is developed. The PER graphs are plotted in logarithmic scale over the average received power. The PER measurement is performed for three LOS scenarios and two NLOS scenarios of the ETSI ITS channel models in data rates 3 Mbps, 6 Mbps, and 12 Mbps, which utilize the BPSK and QPSK baseband modulation scheme. The PER measurement in channel models without availability of a LOS path is carried out with the reduced relative speed of the vehicle to about 40 km/h, in order to be able to receive packets through the Propsim C2.