• Effects of Synchronization Error on Space Time Block Codes Equipped with FSK Waveforms

      Potter, Chris; Kosbar, Kurt; Panagos, Adam; Dynetics, Inc.; Missouri University of Science and Technology (International Foundation for Telemetering, 2009-10)
      Space-time Coding (STC) for Multiple-Input Multiple-Output (MIMO) wireless communication systems is an effective technique for providing robust wireless link performance in telemetry systems. This paper investigates the degradation in system performance when synchronization errors between the transmitter and receiver are present. Specifically, expressions that quantify the increase in symbol-error-rate as a function of symbol synchronization error are derived for a two-transmit and single receive antenna MISO system using binary frequency shift keying waveforms. These results are then extended to the MIMO case. The analytic results are verified with simulation results that show close agreement between the theoretical expressions and Monte Carlo simulation runs.
    • A Method for Tracking the Accuracy of Channel Estimates in MIMO Receivers

      Kosbar, Kurt; Gupte, Abhishek; Missouri University of Science and Technology (International Foundation for Telemetering, 2009-10)
      Multiple input multiple output communication systems offer significant advantages, but only if the receiver has an accurate estimate of the channel state information (CSI). To obtain a CSI estimate, the transmitter must stop sending data, and instead send a training sequence. To maximize throughput, the time spent sending training data should be minimized. This paper describes a method which allows the receiver to track the accuracy of its CSI estimate, so that it can request new training data only when necessary.
    • A Programmable Dual Modulator Testbed for MIMO Applications

      Kosbar, Kurt; Seaber, John; Barkley, Jacob; Ngo, Tony; Poettgen, Adam; Missouri University of Science and Technology (International Foundation for Telemetering, 2009-10)
      Multiple-input multiple-output (MIMO) systems use multiple transmitters and receivers to increase the capacity and reliability of radio frequency communication links used in multipath and disruptive environments. This paper describes a recently designed hardware testbed that can be used as a modulator and transmitter for MIMO systems which use two transmitters. The testbed consists of a field programmable gate array (FPGA) that generates the I/Q baseband signals for the two transmitters. A wide variety of modulation and coding formats, up to data rates of 10 Mbps, can be implemented by reprogramming the FPGA. The dual I/Q outputs from the FPGA are then fed to a pair of quadrature modulators, which have programmable carrier frequencies from 1,025 to 2,450 MHz. The system is implemented on a single printed circuit board, and has dual RF outputs with programmable power levels up to 0 dBm.
    • Symbol Synchronization of GFSK Modulated Signals in a Multipath Environment

      Kosbar, Kurt; Gupte, Abhishek; Missouri University of Science and Technology (International Foundation for Telemetering, 2009-10)
      This paper investigates the performance of a symbol synchronization technique when used for bandlimited modulation formats in multipath environments. The performance was analyzed using Gaussian Frequency Shift Keying as the modulation format, and assume the receiver has no channel state information The symbol synchronization algorithm calculates the minimum sample variance of eye diagrams over varying symbol rate estimates. The system performance was measured through simulations run at various signal-to-noise ratios and over a range of single-reflection multipath channels.