ofdm pilot signals, zero carrier

[venkateshkumar]

ofdm pilot

hai

for 64 ifft size 48 subcarriers + 4 pilot signal + 12 zero carrier is this constant value?

if then for 1024 ifft size how many pilot signals and zero carriers needed

another issue is one frame contains how many symbols ??

how to fix FRAME SIZE?

HELP ME PLEASE...........

I AM confused with concepts

regards

venkatesh.

 

[amihomo]

pilot signals in dvb-t

the number of subcarriers vary from system to system, e.g. in DVB-T mode 2K there are 1705 subcarriers and the fft sise is 1024 .

the number of pilots used in an ofdm system depends on the charactristics of the channel through which the signal is sent.

in DVB-T each frame consists of 68 ofdm symbols

regards

 

[tarakapraveen]

ofdm pilots

Hi,

For 64 subcarriers case in 802.11a the 4 pilots positions is -21,-7,7,21

I think for 1024 subcarriers case the number of pilots increases .There is no need to place at particular place since we are using pilots for the purpose of channel estimation ,more the pilots channel estimation becomes perfect means channel capacity increases,but we hav to conisder the overhead also.

My suggestion is for 1024 subcarriers case place the pilots with period of 14 like above i.e place 14 data carrires in between two pilots.

Regards,
Goud

 

[servicemann]

location of pilot carrier ofdm

See the picture from Mobile WiMAX – Part I: A Technical Overview and Performance Evaluation, August 2006

 

[rmreddy]

pilot carrier ofdm

actuallly the number of pilot carriers, zero carriers depends on the modulation scheme u r using for a particular stream of data and channel conditions ...
for example if u r sending a data stream using QPSk it is to say that the info is more important and hence u try to send few more pilots to ake sure that the data is reached properly...

 

[venkateshkumar]

hai

thanks for ur valuable guidance

thank you guys

regards

venkatesh