A New Family of Time-Limited Nyquist Pulses for OFDM Systems

• Published in: IEEE communications letters 2016-10, Vol.20 (10), p.1943-1946
• Main Authors: Sharique, Mohd, Chaturvedi, A. K.
• Format: Article
• Language: English
• Subjects: Frequency response; Frequency-domain analysis; inter-carrier interference; OFDM; out-of-band power; pulse shaping; Receivers; Signal to noise ratio; Time-domain analysis; Transmitters
• ISSN: 1089-7798; 1558-2558
• DOI: 10.1109/LCOMM.2016.2597841

We first provide the motivation for a new family of time-limited Nyquist pulses for Orthogonal Frequency Division Multiplexing (OFDM) systems by multiplying existing Nyquist pulses in the frequency domain. The condition required for the resultant pulses to have a roll-off factor less than or equal to unity is then established. The roll-off factor is found to be a function of two design parameters. Thus, once the roll-off factor is fixed, there is an opportunity to optimize the two design parameters, such that the signal-to-interference ratio (SIR) in the presence of carrier frequency offset is maximized. As an illustration, a new pulse is designed by multiplying the time-limited Better Than Raised Cosine and RC pulses in the frequency domain, followed by optimization for SIR maximization. The obtained pulse is compared with a pulse, which is known to provide the best out-of-band (OOB) power performance among the known pulses for OFDM systems. From the comparison, it is clear that the obtained pulse provides better SIR performance while maintaining the same OOB power performance.