MIMO and Smart Antennas for Mobile Broadband ... - 4G Americas

Figure 40 – Distribution of the antenna beam width after the optimization. Case 1 is morning and case 2 is afternoon.Distribution of the antenna beam width shown in Figure 40 shows some clusters around 45° and at the upper end above 100°. Thedistribution depends on various input parameters, such as the scenario itself, the traffic distribution, as well as the desired focus onthe optimization objective, as indicated in the figure.It may be speculated that wide beam width pattern will cause higher sector-to-sector interference. Theresults in Figure 39A show a different picture: The actual sector-to-sector interference was notsignificantly reduced by the use of variable beam width. This can be attributed to the fact that it is not justthe beam width, but the combination of beam width and azimuth changes that provides substantialimprovements.3.7 RECONFIGURABLE BEAM ANTENNAS – CYCLICAL TRAFFIC PATTERNMANAGEMENTMeasurements in wireless networks show a clear daily cyclical behavior. An example for the trafficpattern of a single sector, over a 24-hour, 7-days a week period is shown in Figure 41. It can beobserved that the traffic pattern repeats over time.4G Americas MIMO and Smart Antennas for Mobile Systems – October 2012 – All Rights Reserved59