Measuring the Impact of Multiple Terminal Antennas on the Bit Rate of Mobile Broadband Systems Using Reverberation Chambers

The bit rate of new mobile broadband services will be directly affected by the configuration and efficiency of the terminal antennas. Each dB not lost through fading, mismatch and ohmic loss can be used by new (HSDPA and WiMAX) and future (LTE) mobile broadband services for higher user bit rate or use of less spectrum by increasing the modulation rate and/or reducing the coding rate. Fading can be combated using diversity antennas or utilized for higher capacity using partially uncorrelated communication channels created through the use of multiple antennas at both the radio base station and the terminal (MIMO). Low mismatch and low ohmic loss in the antenna and its environment are crucial for high bit rates with terminals using either diversity or MIMO. The only measurement instrument to directly measure the SNR increase of diversity antennas or the increase in capacity of using MIMO antennas is the reverberation chamber. The reverberation chamber simulates a fading environment similar to the one encountered in urban or indoor environments. Measurements in the reverberation chamber are fast and repeatable. The alternative is complex and often unreliable drive tests. Measurements of diversity gain and MIMO capacity in a reverberation chamber are explained and results are presented.