OFDM

[Ankita Sharma]

Hi all,

Can someone please specify the parameters which are needed to maximise Q-factor in OFDM ?

Regards
Ankita

[Gokul Boro .]

Hi Ankita,
If you are working on DD-OOFDM then here I got some ideas for you to maximize Q factor. The Q factor is dependent on Launch Power and Guard Band. You can try changing these parameters. But since minimum GB required is equal to bandwidth of OFDM channel, you can better ignore changing GB and just change the Launch power.
Regards

[Rajguru M. Mohan]

Hi Ankita,
Please specify tha application where you want to apply OFDM
Modulation. In recent we have different architecture and concepts where we could enhance
OFDM according to its applications as:
You can use the specifications of TDS-OFDM or TFT-OFDM
The time domain synchronous OFDM
(TDS-OFDM) has higher spectral efficiency than the standard
cyclic prefix OFDM (CP-OFDM), but suffers from severe
performance loss over high speed mobile channels since the
required iterative interference cancellation between the training
sequence (TS) and the OFDM data block. In this paper, a
fundamentally distinct OFDM-based transmission scheme called
time-frequency training OFDM (TFT-OFDM).

Hope this will help you.

[Rajguru M. Mohan]

Hi Ankita,
In case of High Speed Environments with High Spectral Efficiency and Reliable Performance .
Time-Frequency Training OFDM (TFT-OFDM) is better and compared with TDS-OFDM.
It is summerised as:
Firstly, the iterative channel estimation and IBI cancellation
in TDS-OFDM require that the channel is static
within each TDS-OFDM symbol. However, TFT-OFDM receiver algorithm deals with the fast fading
channel varying within every TFT-OFDM symbol.
TDS-OFDM can only obtain the channel information
at the position of time-domain TS.
Thirdly, TDS-OFDM requires that the IBIs between the
TS and OFDM block should be removed completely,
leading to the mutually conditional relationship between
channel estimation and channel equalization.
Finally, TFT-OFDM adopts the soft decision based ICI
cancellation for symbol detection, which has better performance
than the simple one-tap equalizer in TDSOFDM.
These all difference between different types of OFDM architecture
wiil led you to choose between them as per applications.
Thanks,
Rajguru

[Author]

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