Spectral Precoding for Out-of-Band Power Reduction Under Condition Number Constraint in OFDM-Based Systems

Abstract

Due to the flexibility in spectrum shaping, orthogonal frequency division multiplexing (OFDM) is a promising technique for dynamic spectrum access. However, the out-of-band (OOB) power radiation of OFDM introduces significant interference to the adjacent users. This problem is serious in cognitive radio (CR) networks, which enables the secondary system to access the instantaneous spectrum hole.Existing methods either do not effectively reduce the OOB power leakage or introduce significant biterror-rate (BER) performance deterioration in the receiver. In this paper, a joint spectral precoding (JSP) scheme is developed for OOB power reduction by the matrix operations of orthogonal projection and singular value decomposition (SVD). We also propose an algorithm to design the precoding matrix under receive performance constraint, which is converted to matrix condition number constraint in practice. This method well achieves the desirable spectrum envelope and receive performance by selecting zero-forcing frequencies. Simulation results show that the OOB power decreases significantly by the proposed scheme under condition number constraint.

An efficient technique for out-of-band power reduction for the eliminated CP-STC-shaped system for 5G requirements

“…In the matlab simulation a multipath Rayleigh fading channel under the COST 207 typical urban six-path (TU6) channel model is applied whose power delay profile is shown in Table 5. To illustrate the OOB power reduction, the PSD is obtaining from the power of DFT coefficients of time-domain OFDM signal [20]. The following subsections include demonstration of sidelobes suppression, PAPR and ISI reduction.…”

An Efficient Performance of OFDM-Shaped Symbol for 5G Green Communication Compared to FBMC

“…www.astesj.com Figure 10: PSD of (a) traditional OFDM scheme [22], (b)proposed modified STC-Shaped system scheme and (c) FBMC scheme [23,24].…”