==Difference between FDM and OFDMA==
[[Image:Diff_wave_form.jpg|center|800px600px|thumb| [http://images.google.co.in/imgres?imgurl=http://www.mprg.org/research/OFDM/images/fig1.gif&imgrefurl=http://www.mprg.org/research/OFDM/index.html&h=208&w=383&sz=5&hl=en&start=9&um=1&tbnid=_EbqcjAiE_s27M:&tbnh=67&tbnw=123&prev=/images%3Fq%3DOFDM%2B%252B%2BFDm%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG <font size = "2">'''Difference between FDM and OFDMA'''</font>]]]
[[Image:OFDMA Multi User Access.jpg|center|800px|thumb|<font size = "3">'''OFDMA Multi User Access'''</font>]]
*Orthogonal Frequency Division Multiplexing (OFDM) is a method that allows to transmit high data rates over extremely hostile channels at a comparable low complexity. OFDM has been chosen as the transmission method for the European radio (DAB) and TV (DVB-T) standard. Due to its numerous advantages it is under Discussion for future broadband application such as wireless ATM as well.
[[Image:guard_band.jpg|center|800px600px|thumb| [http://en.wikipedia.org/wiki/OFDMA <font size = "3">'''Subcarrier allocation'''</font>]]]
==Definition of slot==