In orthogonal frequency division multiplexing  overlapping of spectrum would not affect but the synchronization of frequency should be maintained.

In that case, how can the synchronization be maintained, lets say, if the connection requests to be provisioned are dynamic in nature. 

Orthogonal Frequency Division Multiplexing (OFDM)

has recently been proposed as a modulation technique for optical

networks, because of its good spectral efficiency, flexibility, and

tolerance to impairments. We consider the planning problem of an

OFDM optical network, where we are given a traffic matrix that

includes the requested transmission rates of the connections to be

served. Connections are provisioned for their requested rate by

elastically allocating spectrum using a variable number of OFDM

subcarriers and choosing an appropriate modulation level, taking

into account the transmission distance. We introduce the Routing,

Modulation Level and Spectrum Allocation (RMLSA) problem, as

opposed to the typical Routing and Wavelength Assignment

(RWA) problem of traditional WDM networks, prove that is also

NP-complete and present various algorithms to solve it. 

By presenting an optimal ILP RMLSA algorithm that minimizes

the spectrum used to serve the traffic matrix, and also a

decomposition method that breaks RMLSA into its two

substituent subproblems, namely, (i) routing and modulation level,

and (ii) spectrum allocation (RML+SA), and solves them

sequentially. We also propose a heuristic algorithm that serves

connections one-by-one and use it to solve the planning problem

by sequentially serving all the connections in the traffic matrix. In

the sequential algorithm, we investigate two policies for defining

the order in which connections are considered. We also use a

simulated annealing meta-heuristic to obtain even better

orderings. We examine the performance of the proposed

algorithms through simulation experiments and evaluate the

spectrum utilization benefits that can be obtained by utilizing

OFDM elastic bandwidth allocation, when compared to a

traditional WDM network.

Take a look at this publication: https://www.ceid.upatras.gr/webpages/faculty/manos/files/papers/ofdm_jlt_revision_2.pdf

Thanks Gerson. That text answers the questions.

Not sure you still need to simulate Coherent Optical OFDM Systems in Matlab. There are commercial matlab modules for simulation of linear fiber optic coherent OFDM systems that are available with CodeSScientific. The link is:

http://codesscientific.com/fiber-optic-communication-systems-simulations/10/

Also there are commercial matlab modules for compensating laser phase noise in a QPSK system and compensating  fiber chromatic dispersion in a x- span QPSK system. The Link is:

http://codesscientific.com/fiber-optic-communication-systems-simulations/12/

You can go through them. May be they will be helpful for you.

Best Regards,

Kalpana Tewari, PhD

Research Scientist

Thanks a lot Kalpana.