Blind Symbol-Rate Estimation and Test Bed Implementation of Linearly Modulated Signals

• Published in: IEEE transactions on vehicular technology Vol. 64; no. 3; pp. 954 - 963
• Main Authors: Majhi, Sudhan, Ting See Ho
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Approximation; Bandwidth; Baseband; Blinds; Correlation; Estimation; Frequency estimation; Frequency modulation; Modulation; Offsets; Phase (cyclic); Quadratures; Symbols; Timing; Wideband communications; blind symbol-rate estimation; offset quadrature phase-shift keying (OQPSK); cyclic correlation (CC); Baud rate estimation; test-bed implementation; test statistics; measurement
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2014.2327985

Although several blind symbol-rate estimation methods have been proposed for linearly modulated signals, none of these methods are applicable to offset quadrature phase-shift keying (OQPSK)-modulated signals. The frequently used cyclic correlation (CC) methods are unable to estimate the symbol rate for OQPSK signals as the cyclic peak at the symbol-rate frequency disappears due to the presence of an offset between the in-phase (I) and quadrature (Q) components of OQPSK signals. In this paper, a blind symbol-rate estimation for linearly modulated signals has been proposed. The symbol rate of OQPSK signals has also been estimated with no knowledge of modulation schemes. The offset between I and Q components of the received signals is compensated for by using a set of approximate offsets in obtaining the cyclic peak at the symbol-rate frequency. The proposed estimation has a robust performance in the presence of unknown frequency offset, timing offset, and carrier phase. The algorithm is implemented on a test bed to provide experimental results.