A Study on the Tone-Reservation Technique for Peak-to-Average Power Ratio Reduction in OFDM Systems

Abstract

Multicarrier Modulation (MCM) has significant features over Single Carrier Modulation (SCM). Orthogonal Frequency Division Multiplexing (OFDM) is a special form of Multicarrier Modulation with its key feature of Orthogonality. Along with the several advantages of MCM or specifically OFDM, it has some drawbacks, too, in which High Peak to Average Power ratio is the dominant one. There are different techniques available to lower that PAPR. Every technique has its own benefit as well as shortcoming, so each is suitable for different circumstances.

Tone Reservation is one technique in which a small set of subcarriers are reserved for Peak Cancellation Signal. This PCS helps to lower the PAPR of the whole signal. PAPR reduction by tone reservation depends heavily on the quantity, locations and the values of the PCS. Several people around the globe have proposed distinct ways to implement this TR technique. Every approach has its own benefit and is appropriate in different conditions. Some of them have good results but are very complex; on the other hand, some have much lower complexity but the results are also not as excellent. However, within each approach, the appropriate selection of different parameters can make a balance between the results and the complexity. PAPR can be observed by mapping CCDF plots. Results can vary with and without oversampling.

About the Author

Umer Ijaz Butt received his B.S. in Computer Engineering with a major in Telecommunications from the University of Management and Technology, Lahore, Pakistan in 2006. After that, he completed a Masters in Communication Engineering from University of Manchester, UK. The core courses studied included Digital Communications, Optical Communications, Microwave Circuit and Network Analysis and Design, Radar System, Digital Signal Processing, Antennas and Propagation, Personal and Mobile Communications, Semiconductor Materials and Devices, MMIC Components and Technology, Finite Mathematics, and Sequences-Codes and Cryptography. He is currently working with a Multinational Telecommunication company, Mobilink(Orascom) in Pakistan since July 2009.