Sidelobe Suppression for Non-systematic Coded UW-OFDM in Cognitive Radio Networks

In this paper, a novel non-contiguous non-systematic coded unique word (UW)-OFDM system is proposed to opportunistically transmit data on the spectrum holes available in a cognitive radio network. In such a system, the spectral sidelobes of the active subcarriers interfere with the adjacent spectral band used by the primary system. In the proposed scheme, the code generator matrix of the UW-OFDM is designed to suppress the sidelobes. So, there is no need to add any extra processing to the transmitter for suppressing sidelobes. The derived code generator matrix is optimum in the sense of being matched to the best linear unbiased estimator and to the linear minimum mean square error data estimators. The achieved sidelobe suppression is a function of the number of transmitted data symbols. Simulation results show that by a slight decrease in the number of transmitted data symbols, the sidelobes power can be suppressed to zero.

[1]  Tao Jiang,et al.  Extended Active Interference Cancellation for Sidelobe Suppression in Cognitive Radio OFDM Systems With Cyclic Prefix , 2010, IEEE Transactions on Vehicular Technology.

[2]  Wei-Chang Chen,et al.  Spectrally Precoded OFDM and OFDMA with Cyclic Prefix and Unconstrained Guard Ratios , 2011, IEEE Transactions on Wireless Communications.

[3]  Mario Huemer,et al.  Non-Systematic Complex Number RS Coded OFDM by Unique Word Prefix , 2012, IEEE Transactions on Signal Processing.

[4]  Alexander M. Wyglinski,et al.  Sidelobe Suppression for OFDM-Based Cognitive Radios Using Constellation Expansion , 2008, 2008 IEEE Wireless Communications and Networking Conference.

[5]  Michael Schnell,et al.  Reduction of out-of-band radiation in OFDM systems by insertion of cancellation carriers , 2006, IEEE Communications Letters.

[6]  Heidi Steendam.  On the Selection of the Redundant Carrier Positions in UW-OFDM , 2013, IEEE Transactions on Signal Processing.

[7]  Jaap van de Beek.  Sculpting the multicarrier spectrum: a novel projection precoder , 2009, IEEE Communications Letters.

[8]  Heidi Steendam,et al.  Power Spectrum Characterization of Systematic Coded UW-OFDM Systems , 2013, 2013 IEEE 78th Vehicular Technology Conference (VTC Fall).

[9]  Mario Huemer,et al.  Direct vs. Two-Step Approach for Unique Word Generation in UW-OFDM , 2010, ArXiv.

[10]  Behrouz Farhang-Boroujeny,et al.  Multicarrier communication techniques for spectrum sensing and communication in cognitive radios , 2008, IEEE Communications Magazine.

[11]  Hüseyin Arslan,et al.  Mask Compliant Precoder for OFDM Spectrum Shaping , 2013, IEEE Communications Letters.

[12]  Tao Jiang,et al.  Active point modification for sidelobe suppression with PAPR constraint in OFDM systems , 2013, Wirel. Networks.

[13]  Mario Huemer,et al.  Classical and Bayesian Linear Data Estimators for Unique Word OFDM , 2011, IEEE Transactions on Signal Processing.

[14]  Mario Huemer,et al.  On the impact of redundant subcarrier energy optimization in UW-OFDM , 2010, 2010 4th International Conference on Signal Processing and Communication Systems.

[15]  Hüseyin Arslan,et al.  Sidelobe suppression in OFDM-based spectrum sharing systems using adaptive symbol transition , 2008, IEEE Communications Letters.

[16]  Geoffrey Ye Li,et al.  Low-Complexity Spectrum Shaping for OFDM-Based Cognitive Radio Systems , 2012, IEEE Signal Processing Letters.

[17]  B. Parlett.  The Symmetric Eigenvalue Problem , 1981 .

[18]  Hüseyin Arslan,et al.  OFDM for cognitive radio: merits and challenges , 2009, IEEE Wireless Communications.

[19]  Mario Huemer,et al.  A study of data rate equivalent UW-OFDM and CP-OFDM concepts , 2012, 2012 Conference Record of the Forty Sixth Asilomar Conference on Signals, Systems and Computers (ASILOMAR).

[20]  Simon Haykin,et al.  Cognitive radio: brain-empowered wireless communications , 2005, IEEE Journal on Selected Areas in Communications.