A novel technique for peak to average power ratio reduction in OFDM systems

Occasional very high peak to average power ratio (PAPR) is a serious matter of concern in orthogonal frequency division multiplexing (OFDM) systems. One of the best methods to combat this problem is that of partial transmit sequences (PTS) proposed by S.H. Muller and J.B. Huber (see IEE Electron. Lett., vol.33, no.5, p.368-9, 1997). This method has the drawback that it requires an exhaustive search to find the optimum combination of rotation factors giving minimum PAPR. Later, L.J. Cimini, Jr and N.R. Sollenberger (see IEEE Commun. Lett., vol.4, no.3, p.86-7, 2000) proposed a suboptimum technique to reduce the number of searches. We introduce a new criterion to decide a suboptimum algorithm. Also, a parallel branch selection (PBS) method is proposed. It has the advantage over PTS that, at the receiver, there is no need to derotate all the subcarrier phases, which means a considerable saving in computation in the receiver. Results also show that PBS can produce the same complementary cumulative distribution function (CCDF) as exhaustive PTS with 50% reduction in number of trials.