MIMO-OFDMA Measurements; Reception, Testing, and Evaluation of WiMAX MIMO Signals With a Single Channel Receiver

The number of multiple-input-multiple-output (MIMO) orthogonal frequency-division multiple-access (OFDMA) systems is expected to sharply increase in the near future. Engineers who need to test these systems face two difficulties: 1) the lack of descriptive instructions to conduct reliable measurements and 2) the increased hardware cost due to the need for multiple transmitters and receivers. This paper first introduces all the measurable parameters of MIMO-OFDMA systems and provides a clear guide in performing the measurements specific to various parts of the system. Then, it proposes the implementation of the reception of MIMO-OFDMA signals using a single receiver rather than multiple receivers. For this purpose, impairments related to each of the radio frequency front-end components are investigated. The challenges of MIMO-OFDMA measurements are addressed in comparison with single-input single-output measurements. A complete procedure is provided to receive and perform impairment estimation for Worldwide Interoperability for Microwave Access (WiMAX) MIMO signals using a single receiver according to the IEEE 802.16 Standards.