A COMMUNICATIONS SYSTEM FOR MOBILE WIRELESS NETWORKS BASED ON CONCATENATION OF CODE NRZ, IRREGULAR LDPC CODE AND EQUALIZER OF TWO BITS IS STUDIED. THE TRANSMITTER IS COMPOSED OF A NRZ LINE CODER AND IRREGULAR LDPC CODER WITH A LOW ERROR THRESHOLD. THE RECEIVER IS COMPOSED OF THE SUM-PRODUCT DECODER AND LOW COMPLEXITY EQUALIZER WITH A MAXIMUM PROBABILITY ESTIMATION SEQUENCE ALGORITHM. THE COMMUNICATION SYSTEM IS SIMULATED ON AN AWGN CHANNEL AND FAST FADING WITH RAYLEIGH DISTRIBUTION, FOR DIFFERENT WORD SIZES. A MOBILE SPEED OF 150 KM/H IS CONSIDERED. SYSTEM PERFORMANCE IN TERMS OF THE BIT ERROR PROBABILITY (BER) AND SIGNAL-TO-NOISE (SNR) IS CALCULATED FOR NRZ-LDPC CODES, ACHIEVING TO BER OF 10-5 A SNR OF 9 DB WITHOUT EQUALIZER AND A SNR OF 4.5 DB WITH EQUALIZER. THE RESULTS OF THE PERFORMANCE STUDY INDICATE THAT SYSTEM WITH NRZ-LDPC CODES AND EQUALIZER ACHIEVES A CONSIDERABLE REDUCTION OF THE SNR