d ITU-PedB channel model at 3 km/h or a modified ITU-VehA channel model at 120 km/h, [8] a CTC channel coder with a code rate of R = 0.30392, QPSK modulation, uniform distribution of AoD, and SIR = 8 dB. Furthermore, the packet error rate and spectral efficiency are simulated based on a different number of transmit and receive antennas in the downlink when antennas are either correlated, i.e., when inter-antenna distance d = 0.5 A, or when antennas are uncorrelated, i.e., when d = 4 A. Figures 12-11 through 12-14 show the PER and SE as a function of SNR for different antenna configurations and mobile speeds using adaptive beamforming based on a long-term covariance matrix. The channel state information in terms of a long-term covariance matrix is calculated and sent to the BS every four frames. The effect of transmit diversity on the PER and SE in the low SNR region can be seen in the figures. Furthermore, it can be observed that the performance is better for correlated antennas compared with uncorrelated antennas, particularly in the low SNR region. The effect of low and high mobile speeds on the PER and SE have also been investigated and are illustrated in the figures. It is shown that at a given SNR, the increase in mobile speed would increase PER and decrease SE, as would theoretically be expected. In order to investigate the effect of various feedback schemes on the link-level PER and SE, adaptive beamforming with wideband PMI was simulated and the results are shown in Figures 12-15 through 12-18. TABLE 12-17 IEEE 802.16m Link Budget in Various Test Environments for the TDD Duplex Scheme [2] Parameter Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink System Configuration Carrier Frequency (GHz) BS Antenna Heights (m) MS Antenna Heights (m) Cell Area Reliability Transmission Bit Rate for Control Channel (kbps) Transmission Bit Rate for Data 20.23 Channel (Mbps) Target Packet Error Rate for Control Channels Target Packet Error Rate for Data Channels Spectral Efficiency (bits/s/Hz) 0.856 0.830 0.6