Antenna systems with reduced order based on stationary eigen-value optimization (OASE)

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Due to the large number of new and future wireless services and the ever increasing demand for higher data rates with simultaneously increasing transmission quality, the existing wireless channel must be used as efficiently as possible for the transmission of information by utilizing all the available degrees of freedom of a wireless communication system optimally. In order to meet these increasing challenges, a balance between the size of the channel matrix (the system cost) and the hereby achievable channel capacity (max. data rate) must be found while avoiding wireless dead spots (availability respectively reliability of the communication).In this research project, innovative capacity optimized antenna design strategies are developed and verified with the use of time-variant MIMO channel measurements and simulations. By involving information obtained by dynamic channel measurement in the antenna design strategy, the number of antennas (the order of the communication system / its channel matrix) and the hardware complexity of the mobile communication system can be reduced. It is due to the fact that a system with fewer but more optimized antennas can achieve the same channel capacity as a heuristically designed multi-antenna system [Taz12]. To achieve this goal we apply few transmit / receive chains with pattern reconfigurable antennas that may switch between fix radiation patterns. That requires less space and less complexity of the overall system and therefore reduces the hardware and development costs compared to a phase controlled antenna array with adaptive beam-forming. At the same time concerning the achievable mutual information rate and availability of the system only few or no losses should appear, because the described antenna system utilizes the significant eigenvalue trends and eigenvalue groups of the transmission channel, which possess the favorable transmission characteristics. The so-called antenna synthesis will be applied on ray-tracing channel simulations and on channel measurements. Afterwards there will be a comparison and a verification of the results. Predominant directions in automobile channels that are stationary within some limits are a requirement for this. The waveguide effect in street canyons as described in [RMSZ13] is one example for that. These stationary characteristics enable an antenna based optimization already in the design phase of the antenna system that does not need any adaptive channel estimation with dynamic adaption during ongoing communication. Based on these design strategies pattern reconfigurable SISO and MIMO antenna systems can be designed for vehicles.