A method for varying pilot sub-carrier density in OFDMA communications is described. The method comprises calculating channel quality from sub-carriers; determining whether the channel quality is outside a threshold range; selecting a different pilot sub-carrier density for a sub-zone based on the value of the channel quality when the channel quality is outside the threshold range; and setting the sub-zone to the different pilot sub-carrier density. A system for using sub-zones with different pilot sub-carrier densities in OFDMA communications is also described.