In this paper, the application of space-time codes (STCs) to orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems with under-sampled receivers is investigated. In this system, the total available bandwidth is divided into Mt smaller sub-bands. OFDM modulation is adopted in each sub-band, and data are transmitted in all the sub-bands simultaneously. The transmitter properly encodes the data in sub-bands to gain the rich frequency diversity, enabling a low-cost receiver with reduced sampling rate, only one Mt-th of the Nyquist rate. We first show that this system can be analogized to a multiple-input single-output (MISO) system with Mt transmit antennas, by which the application of STC becomes a natural consequence. We then consider employing low-rate space-time trellis codes (STTCs), which can jointly attain the maximal diversity gain and coding gain based on the two design criteria from the MISO analogy. Simulation results with proposed STTCs have verified the superior performance to the previously proposed coding scheme.
|Number of pages||5|
|Journal||IEEE Vehicular Technology Conference|
|State||Published - 17 Oct 2005|
|Event||2005 IEEE 61st Vehicular Technology Conference -VTC 2005 - Spring Stockholm: Paving the Path for a Wireless Future - Stockholm, Sweden|
Duration: 30 May 2005 → 1 Jun 2005