Subcarrier Power Adjustment Technique for Peak-to-Average Power Reduction of OFDM Systems
Rajbanshi,Rakesh
ITTC, University of Kansas
Wyglinski,Alexander
ITTC, University of Kansas
Minden,Gary
ITTC, University of Kansas
In this paper, we propose a novel peak-to-average power ratio (PAPR) reduction algorithm for OFDM systems that employs a two-step approach for adjusting the subcarrier power levels. The first step redistributes the power level across all subcarriers, which slightly reduces the error robustness of the system, while the second step ensures the subcarrier power distribution obeys a subband power constraint.
The resulting power levels satisfy regulatory requirements across the transmission spectrum while simultaneously reducing the PAPR and attempting to maintain a degree of error robustness. Since no overhead information is required, the proposed algorithm does not incur a throughput penalty. Simulation results for a 256-subcarrier OFDM system employing QPSK symbols and the proposed algorithm show a PAPR reduction of 1.5 dB for a complementary cumulative distribution of 0.1%.
Rakesh Rajbanshi is currently pursuing a Ph.D. degree in electrical engineering at the University of Kansas. He received his M.S. degree in electrical engineering from University of Southern California in 2003 and his B.E. in electrical engineering from Tribhuvan University, Nepal in 2000. As a graduate research assistant at the Information and Telecommunication Technology Center (ITTC), Rakesh is involved in the NSF National Radio Networking Research Testbed (NRNRT) project, which focuses on the use of cognitive radios for dynamic spectrum access. His current research interests are in the areas of wireless communications, cognitive radios, high speed data modulation techniques (e.g., OFDM), and dynamic spectrum access networks. He can be reached at rajbansh@ittc.ku.edu.