LTE-A is becoming the standard of 4G with its perfect performance.However

LTE-A demands that the transition band should be very narrow and the ripples in pass band should be very low in the front digital filter.To meet the demands

this paper proposes a design method for the digital filter

using a frequency-response masking technology with optimization of the inserting gene M

the length of the filter and the range of the ripples.Simulation results show the complexity are 68

79

87

87

87

and 87

when the bandwidth are 1.4MHz

3MHz

5MHz

10 MHz

15MHz and 20 MHz with the standard of LTE-A.This indicates that the design in this paper meets the demands

and has lowered 50% of the complexity and achieved better performance compared with traditional FIR filters.