On a characterisation of Large-Scale channel parameters for distributed (multi-link) MIMO — The impact of power level differences

In configurations with spatially distributed communication sources a receiving terminal simultaneously receives multiple signals. Due to the receiver's limited dynamic range, a receiver's perception of any particular radio-link will depend on the total power received from all links. In this respect, the problem at hand has parallels with the well-known near-far problem in the uplink of CDMA systems. In this contribution, a strategy of joint representation of distributed/cooperative wideband MIMO channels with common sink is proposed. The approach is based on the observation that perception of Large-Scale model parameters, like spreads, depends on the effective dynamic range. Due to the differences in the peak power levels of the cooperative links, the effective dynamic range for the weaker links will be lower and, therefore, values of Large-Scale channel parameters should be adjusted accordingly. The proposed solution requires that the distribution of the peak power level differences is statistically characterised for particular multi-link configurations. This is then used to modify the distributions of the Large-Scale parameters to account for the limited dynamic range of the receiver. The relevant dependences between Large-Scale parameters are illustrated for a multi-cell configuration, using measurements conducted in Ilmenau during 2008.