Interference Analysis and Optimal Window Design for Windowed UFMC Systems

In a universal filtered multi-carrier (UFMC) system, the windowing operation improves the intersubband interference. However, the window function destroys the subcarrier orthogonality in the subband to some extent and is also more susceptible to carrier frequency offset (CFO). Therefore, in this paper, the signal and interference analysis of a windowed UFMC system in the presence of CFO is first investigated theoretically, and then the system signal to interference plus noise ratio (SINR) expression is derived. Second, a window function optimisation model aiming at maximizing the geometric mean of subcarrier SINR is constructed and solved by the successive convex approximation (SCA) algorithm. Finally, the SINR as well as the symbol error rate (SER) with different window functions are compared by simulation. Results show that the window function can effectively reduce the UFMC system interference. Moreover, compared with the traditional window function, the proposed optimal window function shows a better signal to noise ratio (SNR) performances and can significantly improve the SER.