On increasing the spectral efficiency more than 100% by user-in-the-control-loop

OFDMA has become the key technology for future cellular wireless networks like the IMT-Advanced systems IEEE 802.16m and 3GPP LTE-A. The advantage of allowing different modulation&coding schemes (PhyModes) adaptively for each radio resource is at the same time a new disadvantage because the performance is now distance-dependent from the base station (BS) and the total spectral efficiency depends on how user terminals (UTs) are provided with service opportunities. Instead of increasing the effort to support cell-edge users with high data rates this paper investigates the chances of letting the user participate in the process such that his mobility becomes utility-driven, in a similar way the user behaves in 802.11 hotspot areas. The user's willingness to move to regions of higher SINR must be supported by a display of the current situation (and indications where to move) plus a utility model (lower cost or higher data rate) which motivates moving a distance monotonic in the utility value. By giving input to the user and utilizing the output of his behavior the user becomes a member of the control loop, in a system theoretic sense. The paper shows numeric results of common scenarios and compares the old and new paradigms.