Peak-to-average ratio reduction with Tone Reservation in multi-user and MIMO OFDM

We extend Tone Reservation for peak-to-average ratio reduction in MIMO-multiuser OFDM scenarios. First, we consider a multi-user BC (broadcast) situation where a precoding is applied at every carrier. This is considered to be a very demanding situation for peak-to-average ratio reduction. Tellado´s Tone Reservation, however, is especially suited for this situation, as well. It reserves all spatial dimensions of the reserved carriers and has hence not to take into account possible implications resulting from precoding. Secondly, for a point-to-point (pt2pt) MIMO-OFDM scenario, we assume that the last eigenchannel is too weak to be used for transmission, thus, reserving it will offer redundancy for peak-to-average ratio reduction. The algorithm in both cases completely operates in time domain and is shown to additionally profit from multiple spatial dimensions when iteratively only the highest peak spatial components are processed.