Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Thanks. But why this OFDM technique is good for high speed data communication system? Is it just because it is good in frequency selective channel and ISI......and this is the envirolment when high data speed communication employed....correct me if I am wrong....Thanks
High speed transmission is determined from channel bandwidth and S/N, because these two factors limit data rate, you can acheive data rate as high as channel capacity by using any scheme. The point is that in mobile envoirment because of multipath effect high data rate schemes produce ISI which in turns produce lot of errors and hence data rate is decreased, so OFDM technique is said to be efficient for high data rates because it can remove the effect of multipath and delay spread, so high data rates are possible without any ISI at the receiver.
The other way to look at this problem is to consider niquist theorm.
According to the theorm, If bandwidth is W and used channel time is T, you can transmit maximum of 2*W*T independent symbols.
Hnce for single carrier we can tranmite 2WT independent symbols.
In OFDM case, symbol duration is T hence BW per sub channel is 1/T. Total number of subchannels is W/(1/T)=WT, and each carrier can TX 1 complex symbol ( that is 2 real symbols).
Hence total independent symbols during T--> 2*WT
wich is the same as the single carrier case....
The advantage of OFDM is channel estimtimation is very simple. whereas in single carrier case, complexity may be 5-10 fold
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
