Rapid MIMO-OFDM

Rapid MIMO-OFDM Prototyping
Rapid MIMO-OFDM Prototyping

MIMO-OFDM uses multiple transmit and receive antennas to provide simple equalization and high capacity. As the research and the standardization efforts on MIMO-OFDM technology continues to progress, it becomes increasingly important to test the real world performance of MIMO-OFDM systems. To this effect we constructed a MIMO-OFDM prototype with support from National Instruments, the National Science Foundation, and Intel. We used our prototype for two purposes: to implement a full physical layer MIMO-OFDM link as in IEEE 802.11N and to use perform MIMO propagation channel measurements. This page describes the results of our prototyping effort from 2004. It is provided for archival purposes.

Prototype Specifications

We used National Instrumentsâ Radio Frequency (RF) hardware and LabVIEW for our prototype. The National Instruments platform gives the flexibility to change many system parameters easily through a software interface. The system described here implements a two-transmit two-receive antenna MIMO communication system with a bandwidth of 16MHz and an adjustable carrier frequency.

System Implementation

Using the hardware platform, we created a full MIMO-OFDM physical layer link. The link is configurable so that it is possible to implement a number of different MIMO schemes (i.e. spatial multiplexing, transmit diversity, Alamouti coding, linear dispersion codes) to test and compare their real world performance. The difference among these various schemes is that some provide greater data rates while others provide greater signal robustness.

Channel Measurements

We used the system to prototype to test and measure realistic MIMO propagation channels. This information can be used to create realistic channel models for system simulations as well as to research various characteristics of the channel that we can exploit to increase capacity and signal strength.

Download LabVIEW VIs (these are several years old, provided for historical purposes)

Documentation

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