Orthogonal frequency division multiplexing (OFDM) has been widely adopted formodern wireless standards and become a key enabling technology for cognitiveradios. However, one of its main drawbacks is significant spectral leakage dueto the accumulation of multiple sinc-shaped subcarriers. In this paper, wepresent a novel pulse shaping scheme for efficient spectral leakage suppressionin OFDM based physical layer of IEEE 802.11af standard. With conventional pulseshaping filters such as a raised-cosine filter, vestigial symmetry can be usedto reduce spectral leakage very effectively. However, these pulse shapingfilters require long guard interval, i.e., cyclic prefix in an OFDM system, toavoid inter-symbol interference (ISI), resulting in a loss of spectralefficiency. The proposed pulse shaping method based on asymmetric pulse shapingachieves better spectral leakage suppression and decreases ISI caused byfiltering as compared to conventional pulse shaping filters.
展开▼
