Real-time concepts for MIMO-OFDM

We present a concept for implementing a real-time MIMO-OFDM system on a hybrid FPGA/DSP software-radio platform. The basic system parameters are chosen similar to the HiperLAN/2 standard using a fixed frame structure. A new C preamble is defined, in order to identify the individual transmit antennas at the receiver. We propose a code-multiplex approach in order minimize the channel estimation error. With the new preamble, the correlation circuits at the receiver can be reused for all carriers and no multipliers must be used. Three methods to increase the channel tracking rate at the receiver are discussed and we argue that a combination of them may be suitable for a wide range of mobility scenarios.