eived power from transmit (Tx) antenna 1 (blue color), the scheduler starts to favor this antenna on all RBs for certain UE positions. This can be seen where the sum throughput for the "red" Tx antenna drops to zero. The measured average sum gross throughput for the single UE using the full bandwidth and spatial multiplexing when possible was above 120 Mb/s in the high-SNR indoor scenario, with a maximum rate of 157 Mb/s when all RBs on the two Tx antennas used 64 QAM. Depending on the chosen code rate (e.g., 3/4), a net throughput above 100 Mb/s could be real- ized, as targeted by 3GPP. The bottom plot shows the uncoded BER when exploiting fast link adaptation. The target BER was set to 10-3 to ensure error-free transmission after forward error correction. reconfigurable hardware test bed. First experiments with a single user showed net peak rates above 100 Mb/s in very good channels and robust transmis- sion when combined with basic link adaptation functionalities in the downlink. The sample points were taken every 300 ms with an average BER measurement over this time and a slow movement through the room. Therefore, the located bit-loading pattern does not vary much over the 300 ms. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology Time (s) Figure 11.15 Measured sum throughput along the office with various Tx and Rx antenna combinations. Sum rate measured at UE. 11.2.4.4 Measured Rates with Different Antenna Configurations In Figure 11.15, the measured data rates for the various Tx and Rx antenna con- figurations are plotted versus the position on the track through the office. For SISO (bottom plot), robustness seems to be the issue. The sum rate shows fluctuations because no spatial diversity can be exploited. Frequency diversity is also limited in the indoor scenario, with a coherence bandwidth of 5-10 MHz. For such indoor scenarios, the case for CDD of 10- to 20-tap delay to be applied is ideal. The CDD technique introduces additional frequency diversity into t