QPSK-OFDM Transmitter and QPSK transmitter

[kavitha_bonthu]

Regarding OFDM

hello every body
I would like to know the difference in transmitted power for QPSK-OFDM Transmitter and QPSK transmitter in same conditions
Does QPSK-OFDM system requires more power tha n QPSK system???


Regards

 

[alqasim]

Re: Regarding OFDM

explain more my friend

 

[g.s.javed]

Re: Regarding OFDM

Friend. The QPSK- OFDM system takes lesser power than the QPSK system. The reason is the no. of bits to be transmitted are grouped in a dense manner in the channel. More information is given out with less power being sent.

The QPSK system handles less no of bits. Hence lesser signal changes. Effectively, for the same no of bits transferred, power used by the QPSK system is greater.

 

[gayathri123]

Re: Regarding OFDM

i need to know OFDM and to send the input modulaion signal.

 

[bingdao89]

Regarding OFDM

i agree with g.s.javed！

 

[gayathri123]

Re: Regarding OFDM

i need to know OFDM tutorial in detail

 

[gayathri123]

Re: Regarding OFDM

ineed to know how to reduce PAPR in OFDM through linear constellation precoding techniques.

 

[Aya2002]

Re: Regarding OFDM

if you need to know what is OFDM please see this tutorial

 

[Aya2002]

Re: Regarding OFDM

also see this one

 

[Aya2002]

Re: Regarding OFDM

Implementation Issues
in OFDM Systems

 

[bbatif]

Re: Regarding OFDM

Some books:

Theory and Applications of OFDM and CDMA : Wideband Wireless Communications
By Henrik Schulze
*http://mihd.net/fc73is


Adaptive Wireless Transceivers: Turbo-Coded, Turbo-Equalized and Space-Time Coded TDMA, CDMA, and OFDM Systems
By Lajos Hanzo, C. H. Wong, M. S. Yee,
**broken link removed**

Wireless OFDM Systems : How to make them work? (The International Series in Engineering and Computer Science) By Marc Engels
***broken link removed**

Orthogonal Frequency Division Multiplexing for Wireless Communications (Signals and Communication Technology)
By Ye (Geoffrey) Li (Editor), Gordon L. Stuber (Editor)
*http://mihd.net/ir3dqs
***broken link removed**

 

[Communications_Engineer]

Re: Regarding OFDM

Friend. The QPSK- OFDM system takes lesser power than the QPSK system. The reason is the no. of bits to be transmitted are grouped in a dense manner in the channel. More information is given out with less power being sent.

The QPSK system handles less no of bits. Hence lesser signal changes. Effectively, for the same no of bits transferred, power used by the QPSK system is greater.

bingdao89 Posted: 07 Jan 2009 11:24 Post subject: Regarding OFDM

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i agree with g.s.javed！

I dont agree. QPSK-OFDM takes the same amount of power as a single carrier QPSK. I'm sure you're forgetting that the performance of OFDM is like the performance of the underlying modulation scheme.

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https://groups.yahoo.com/group/telecom_research/

 

[pavan_85]

Re: Regarding OFDM

Undoubtedly n-qpsk will take more power than ofdm.
In ofdm, the bandwidth used is less in comparision with QPSK, this implies that the power used to transmit the data in OFDM will be less than what it takes for QPSK.

 

[Communications_Engineer]

Re: Regarding OFDM

Undoubtedly n-qpsk will take more power than ofdm.

Why? If OFDM will use the same modulation scheme then for the same BER constraints the Eb/No would be the same.

In ofdm, the bandwidth used is less in comparision with QPSK, this implies that the power used to transmit the data in OFDM will be less than what it takes for QPSK.

Actually the bandwidth used by single carrier is divided among multiple carriers. So like I said, for same bandwidth, same BER both QPSK-OFDM and QPSK-Single carrier would consume the same power. If you use an equalizer with OFDM, then use one with Single-carrier as well.

If you do not agree, please provide reasoning


:idea: Ooops! I wrote the message while busy on something else, OFDM would actually require more power. Why? because in may happen that the peaks coincide and the power requirement increases.Remember the peak-to-average problem with OFDM

 

[gayathri123]

Re: Regarding OFDM

i need know how to reduce PAPR in ofdm. i have done basic coding for OFDM structure. i want concept ofPAPR reduction in OFDM.