he channel. One would expect fewer rate variations after applying CDD. Figure 11.15 (MISO plot) shows improvement in throughput and fewer rate fluctuations toward low values. Here, any spatial diversity between the antennas can be exploited. Moreover, if one of the antennas shows frequency selectivity, this additional gain is also realized. The blue and red lines represent the throughput contributions from Tx1 and Tx2. The third plot from the top depicts the rate in SIMO mode by applying an MRC diversity detector. The diversity gain in both MISO and SIMO is on the order of two. The SIMO mode has an additional 3-dB power gain over MISO mode. The top plot in Figure 11.15 shows the achieved rate with MIMO antenna configuration. First, we point out the difference between MIMO configuration and MIMO mode transmission. MIMO mode transmission C 2009 by Taylor & Francis Group, LLC Early Real-Time Experiments and Field Trial Measurements Throughput [Mbps] Figure 11.16 CDF of the measured throughput in the office scenario with single (SISO, MISO, SIMO) and dual (MIMO) streams. is a subset of MIMO antenna configuration. In spirit, the advantage of MIMO antenna configuration is that it includes SIMO and MISO transmission modes by link adaptation. Therefore, the RBs are loaded in single- or dual-stream mode based on actual channel realization. Further, flexible mode selection is applied inde- pendently to each RB in a broadband OFDMA system. It is not straightforward whether fixed MIMO mode transmission alone would improve the performance in a cellular system because a random user could be experiencing a low SINR, in which case single-stream mode is capacity optimal. The maximum achieved rate is 157 Mb/s. Figure 11.16 characterizes the throughput performance gains with cumulative distribution function (CDF) plots. We see clear diversity gains from antenna selec- tion of MISO and the receive diversity of SIMO. Adaptive MIMO transmission outperforms the single-stream modes. 11.2.5 Outdoor Results The antenna configuration measu