Enhanced OFDM techniques for fragmented spectrum use

OFDM has been selected as the basic technology for most of the recent and emerging broadband wireless systems. It is under consideration also for co-existence scenarios where unused frequency slots between narrowband radio channels are aggregated for broadband data transmission purposes. In such scenarios, the limited spectral containment, i.e., the high level of spectral side lobes, becomes a serious issue, along with the general issue of high peak to average power ratio (PAPR) of OFDM. These two issues have received considerable attention from the research community. In this paper, it shown how two successful methods, edge windowing for spectral shaping and partial transmit sequences (PTS) for PAPR reduction, can be combined in a computationally efficient way to handle both issues together. The proposed scheme is elaborated for an LTE-based non-contiguous OFDM scheme and the resulting spectral leakage and PAPR characteristics are evaluated.