On PAPR and OOB Interference Issues in IEEE 802.11a Physical Layer Signals

摘要

Orthogonal frequency division multiplexing (OFDM) is a profound variant of multi-carrier technology. It plays a vital role in the implementation of the Institute of Electrical and Electronics Engineers (IEEE) 802.11a wireless local-area network (WLAN) standard. The technology is blessed with the attributes of efficient spectral utilization and high-speed transmissions. It has immense scope of meeting the stringent requirements for the fourth generation (4G) systems as well. However, a few limitations are associated with it. This paper addresses high peak-to-average power ratio (PAPR) and out-of-band (OOB) interference as the major challenging issues. In this, it is proved that PAPR is a function of the number of sub-carriers and the modulation-order of sub-carrier modulation scheme used. Further, OOB interference is proved to arise as a consequence of high PAPR. Hence it is heuristically justified that OOB interference is also governed by the same factors as PAPR. In the present work, the concept of over-sampling has also been used for the generation of OFDM signals. Finally, an insight into the existing solutions for PAPR reduction is given.