OFDM PON

[Ranjeet Kumar]

How could i get Max.Q-factor and Min. BER in OFDM PON. If Possible please upload osd file of the same. I am unable to get values in BER analyser.

[alistu]

Hi Ranjeet,

Could you please upload the corresponding file so that I would be able to make the necessary changes to it in order to improve the design? If the file you are referring to is the file you have uploaded in the other forum, please verify that. (Making changes take some time, so please upload the file with latest changes)

Regards

[Aabid Baba]

Hello Ranjeet,
There are numerous ways to do it. You can vary different parameters of your design. As alistu said , if possible upload the .osd file of your simulation and we may help accordingly.
For now one thing you can do to increase the Quality factor is increasing the symbol rate in the layout parameter tab or increase the power for transmission if permitted to do so. These are basic tricks to increase quality factor however it would be appropriate if you upload your osd file.

regards

[FAYIQA NAQSHBANDI]

Hi Ranjeet

Did you check the sample files for access systems in optiwave 14.I think you might find a few samples for OFDM PONs.
And regarding the BER and quality factor improvement..is it that you are not getting any result..or you want to optimize your results ?

Regards

[alistu]

Hi Fayiqa,

So as to be more accurate, none of the the examples available in OptiSystem regarding OFDM or passive optical networks is an implementation of PON OFDM. However, as you have suggested they contain valuable information regarding design and implementation of such networks.

Regards

[Karan Ahuja]

Also DWDM PON architectures are of high interest and are on the way to becoming commercially realized, the bandwidth can be substantially scaled up compared to common PON networks concepts. AWG based structures for MUX/DEMUX applications in WDM-PON networks are ideal, adapting perfectly to PON architectures, allowing cyclic character and are leveraging the state of the art PLC processing techniques. The recent progress of AWG design concepts for DWDM PON architectures and their athermal packaging techniques, now suitable for mass production in low cost manufacturing countries, are discussed. The state of the art reliability performance for industrial and in particular DWDM PON applications are demonstrated. AWG based DWDM PON network architectures are elaborated comparing other existing PON network concepts.And as fas as theoretical aspect of the implementation is concerned i agree with karan ahuja that OFDM has the ability to transmit information with high data rates which has made it popular. OFDM has been used in many different applications in the RF domain
such as digital audio broadcasting (DAB), digital video broadcasting (DVB), and Wireless Local Area Networking (WLAN). OFDM was introduced to
optical domain in 2005, and has since been studied and investigated in two main techniques classified according to the detection scheme. The first technique is the direct detection optical OFDM (DDOFDM) and the second technique is the coherent optical OFDM (CO-OFDM). A direct detection optical OFDM aims for simpler transmitter or receiver than CO-OFDM for lower costs. DD-OFDM has an advantage that it is more immune to impulse clipping noise.

You may refer to this paper in this regard
http://ieeexplore.ieee.org/xpl/login.jsptp=&arnumber=4054038&url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumb

[Karan Ahuja]

I want to add that the integrated semiconductor optical amplifier (SOA) with a reflective electro-absorption modulator (REAM) is a promising candidate for the colorless optical network unit in a wavelength-division-multiplexed passive optical network (WDM-PON), due to its low chirp and wide bandwidth. However, 40 Gb/s operation of REAMs (bandwidth <; 20 GHz) still encounters severe intersymbol interference. Furthermore, Rayleigh backscattering (RB) and discrete reflections cause strong beat noise in WDM-PONs with single-fiber loopback configuration. In this paper, we present two novel techniques based on electrical equalization for a 40-Gb/s single-feeder WDM-PON based on SOA-REAM. The first method is to employ partial-response (PR) signaling and a noise predictive maximum likelihood (NPML) equalizer at the upstream receiver. The other one combines correlative level (CL) pre-coding with partial-response maximum likelihood (PRML) equalization. We experimentally demonstrate a 40-Gb/s uplink of 20 km using a 20-GHz SOA-REAM in a WDM-PON by both PR-NPML and CL-PRML. The results also verify the superiority of PR-NPML over the previously reported equalizers. Moreover, compared with PR-NPML, CL-PRML further improves the system performance. Experiments prove that the tolerance to beat noise and the receiver sensitivity are enhanced by 4 dB and 0.8 dB, respectively, at a bit error ratio of 2 × 10-4.

Here is the link of this paper
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6360172&url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D6360172

[FAYIQA NAQSHBANDI]

Hi ranjeet.

Yes any sample file you will find for PONs in optiwave will just give you an idea about how u need to implement your system.
Otherwise you will of course have to design your system on your own based on the requirements your system demands.

Regards

[Ranjeet Kumar]

Thanking you all for considering my problems.
Here i am uploading osd file OFDM PON of 4 users using unidirectional fiber. If it is someone suggest or upload osd file using bidirectional fiber and transreceivers.

Attachments:

1. OFDM-PON.osd

[alistu]

Hi Ranjeet,

Since you are using OS12 OFDM component for a coding of more than 2 bits per symbol, I suggest you make necessary changes to the receiver to make it like the screen shot attached in the comment addressed below:

some help please

Then please upload the modified file.

Regards

[Karan Ahuja]

Hi Ranjeet.
I would like to mention that the wavelength-division-multiplexed passive optical network (WDM-PON) has been generally regarded as a promising solution to the next-generation access network that will be required to deliver services over 40 Gb/s. However, fiber dispersion often limits the capacity and reach of WDM-PONs. Compared with dispersion compensation fiber, which is bulky and expensive with significant power loss, digital signal processing is a more suitable way to mitigate chromatic dispersion in PONs. Furthermore, expense is a critical concern in the WDM-PON, due to its need for a large number of lasers and a complex wavelength control mechanism. One practical solution is to reuse the downstream (DS) signal as the carrier for the upstream (US) modulation. In this case, the residual DS signal after remodulation can seriously degrade US transmission. In addition, system performance can be deteriorated by the unwanted reflection as uplinks and downlinks share one wavelength. In this paper, we propose using modified duobinary (MD) coding in the DS to improve its dispersion tolerance and reduce the crosstalk between DS and US induced by remodulation and reflection. MD is a correlative level code that can reduce signal bandwidth and achieve DC balance. We demonstrate a 15 km WDM-PON delivering a 40 Gb/s MD-coded signal in the downlink and a 10 Gb/s on-off keying signal in the uplink. Compared with no coding, the maximal allowable extinction ratio of the DS signal (ERd) is improved by 4 dB. Moreover, the reflection tolerance of the uplink and downlink is enhanced by 5 and 4 dB, respectively. In addition, investigations on the use of different equalizers in the DS to further suppress fiber dispersion confirm that the superior performance of nonlinear equalization in MD-coded transmission and that the network reach can be extended to 25 km by a nonlinear decision feedback equalizer.
Hope this will give you an idea.
http://ieeexplore.ieee.org/xpl/login.jsptp=&arnumber=6645106&url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D6645106

Thanks

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