MIMO OCDM with reduced PAPR

Abstract

Chirp also known as linear frequency modulated waves are signals, having frequency and phase vary with time in a certain manner and is found in many applications. Its ability of pulse compression and spread spectrum finds its application in the area of radar systems and communication systems. This paper presents a Multiple Input Multiple Output Orthogonal Chirp Division Multiplexing (MIMO OCDM) system. The system is able to orthogonally multiplex a group of chirp wave form and it is best for high speed communication. Fresnel transform which is originating from classical optics is the kernel of MIMO OCDM system; it achieves better spectral efficiency for chirp spread spectrum just as OFDM done for FDM system. The proposed system can be digitally implemented by using discrete Fresnel transform. The results and discussions reveal that MIMO OCDM system can be easily integrated into MIMO OFDM system. One of the main drawbacks of OFDM system is the presence of high peaks at the IFFT output. The methods to reduce PAPR in OFDM system can be easily applicable to OCDM system. In MIMO OCDM system, the PAPR is reduced by using Modified Tone Reservation method. The simulations are done by using MATLAB. The chirp signal has a wideband of spectrum so that, it is immune to multipath fading, channel noise and Doppler Effect within the channel. So MIMO OCDM system is also immune these adverse effects and also effectively use multipath diversity. From the analysis it is clear that the proposed system MIMO OCDM system outperforms conventional MIMO OFDM system.