A study of channel hardening in a large-scale antenna system has been carried out by means of indoor channel measurements over four frequency bands, namely 1.472 GHz, 2.6 GHz, 3.82 GHz and 4.16 GHz. NTNU's Reconfigurable Radio Network Platform has been used to record the channel estimates for 40 single user non-line of sight radio links to a 64 element wide-band antenna array. By examining the rms delay spread and the ratio of the normalized subcarrier to average SISO link power of the radio channel received by a single user after combination, the hardening of this equivalent channel is analyzed for various numbers of nodes. The channel hardening merits show consistent behaviour throughout the frequency bands. By combining 16 antennas the rms delay spread of the equivalent channel is reduced from above 100 ns to below 35 ns with significantly reduced variation in the channel power.

翻译：通过对四个频率波段,即1.472千兆赫、2.6千兆赫、3.82千兆赫和4.16千兆赫的室内频道测量,对大型天线系统中的频道加固进行了一项研究。 NTNU的可配置无线电网络平台用于记录40个单一用户非视线无线电连接至64个宽宽度元素天线天线阵列的频道估计数。通过检查一个用户在组合后收到的无线电频道的Rms延迟扩展和正常子载波与平均SISO链接的比重,对等同频道的加固为多个节点进行了分析。频道加固的优点显示整个频率波段的一贯行为。通过将16个天线合并,等同频道的延迟扩展从100毫秒以上减少到35毫秒以下,频道的变异性显著缩小。