Both long term evolution (LTE) and IEEE 802.16m technologies have the advantages of a high transmission rate and wide transmission bandwidth, and they play essential roles in modern mobile wireless communication systems. The information transmission processes between mobile users and base stations inevitably involve some propagation losses. The losses include shadow fading loss due to blocking by buildings and obstacles and the Doppler effect caused by the relative motion of base stations and mobile users, and these effects result in signal fading at the receiver terminals. To maintain good system performance and service quality, the selection of a suitable modulation format is necessary when wireless signals are transmitted. Different traffic services have their own requirements of service quality. On the basis of the specifications of the IEEE 802.16m and LTE systems, we study their performance when the system parameters are varied. The system parameters include the system bandwidth, the transmitting powers of the base station and mobile, the antenna heights, the orthogonal frequency division multiplexing (OFDM) parameters, and the system load. We also analyze the system performances of the system bit error rate and block error rate (BER) due to the effects of path loss and noise.