On the EMC of the propagation of 2.4 GHz ISM signals in environments with complex metallic structures - A cost-effective measurement setup

The 2.4 GHz ISM band is a commonly used frequency band all over the world. Despite microwave ovens many communication systems operate in this part of the wireless spectrum. Usually these systems are used for data communication at low distances with medium to high data rates. Well-known examples for these systems are Bluetooth (IEEE 802.15.1) and Wi-Fi (IEEE 802.11b/g/n). With the today's available high sensitive receivers the systems can also be used for data transmissions in the several 100 m range. A new operation field can be the ship-to-shore communication in harbor areas. Here the highly reflective environment (containers, cranes and other metal structures) may interact with the signal in an unwanted manner. As the propagation scenario is complex due to the permanently changing multipath propagation the EMC environment is also under permanent change. In order to guarantee the EMC i.e. a reliable transmission of data the influence of multipath propagation on the transmission quality has to be known. In this paper a low-cost system is described to measure the multiple reflections in such a propagation environment. The effects on the transmission are discussed and first ideas on how to deal with it are presented. These investigations and measurements are necessary in order to realize a reliable ship-to-harbor communication in a complex metallic structure environment. The results are assignable on comparable environments.