On Random and Multidimensional Channel Effects in Cluttered Environments

Machine-to-machine devices have the potential to be placed in environments that are less than ideal for wireless propagation, such as factory floors or within metallic enclosures. In this letter, we illustrate that such environments not only produce the expected multipath, but can also depolarize the signal across all three spatial dimensions. Furthermore, we show that these effects are multidimensional in which they are highly sensitive to extremely small changes in user placement and frequency of operation. That is, these channels exhibit randomness based on a user's action. These effects motivate new channel characterization approaches and metrics along with the development of tripolar antenna designs. This letter concludes by presenting the efficacy of such a prototype antenna.