How do you evaluate the performance and reliability of MIMO systems in real-world settings?

1 Channel modeling

The first step to evaluate the performance and reliability of MIMO systems is to model the wireless channel accurately. The channel model captures the characteristics of the propagation environment, such as the path loss, the delay spread, the angular spread, and the correlation among the antennas. The channel model can be based on theoretical models, such as the Rayleigh fading model, the Rician fading model, or the Kronecker model, or on empirical models, such as the COST 2100 model, the 3GPP model, or the WINNER model. The choice of the channel model depends on the frequency band, the antenna configuration, and the scenario of interest.

2 Performance metrics

When evaluating the performance and reliability of MIMO systems, it is important to define metrics that reflect the objectives and requirements of the system. Common performance metrics include capacity, which is the maximum achievable data rate under a given SNR and CSI; diversity gain, which is the improvement in reliability compared to a single-antenna system; multiplexing gain, which is the improvement in data rate; spectral efficiency, which is the ratio of data rate to bandwidth; and energy efficiency, which is the ratio of data rate to power consumption.

3 Simulation tools

The third step to evaluate the performance and reliability of MIMO systems is to use simulation tools that can implement the channel model and the performance metrics. Simulation tools can help you compare different MIMO schemes, such as spatial multiplexing, spatial diversity, beamforming, or precoding, and optimize the parameters, such as the number of antennas, the modulation scheme, the coding scheme, or the feedback strategy. Simulation tools can also help you analyze the effects of various channel impairments, such as channel estimation errors, feedback delays, or quantization errors. Some of the popular simulation tools for MIMO systems are MATLAB, Simulink, NS-3, or OMNeT++.

4 Testbeds and field trials

The final step to evaluate the performance and reliability of MIMO systems is to conduct testbeds and field trials that can validate the simulation results and measure the real-world performance. Testbeds and field trials are essential for assessing the feasibility, scalability, and robustness of MIMO systems in different environments, such as urban, rural, indoor, or outdoor. Additionally, these tests can help identify and solve practical challenges and limitations of MIMO systems, such as hardware imperfections, synchronization errors, or interference management. Examples of testbeds and field trials for MIMO systems include the Eurecom MIMO Open Air Testbed (MIMOA), the Bristol Is Open project, and the MAMMOET project. The former is a platform for testing MIMO techniques in real-time using software-defined radios; the latter is a city-scale testbed for testing MIMO techniques in a dense urban environment using massive MIMO antennas; finally, the MAMMOET project is a European project for testing MIMO techniques in a mobile environment using moving vehicles and drones.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?