Article

Temporal Synchronization of MIMO Wireless Communication in the Presence of Interference

MIT Lincoln Lab., Lexington, MA, USA
IEEE Transactions on Signal Processing (Impact Factor: 2.81). 04/2010; DOI: 10.1109/TSP.2009.2037067
Source: IEEE Xplore

ABSTRACT In wireless communications systems that potentially operate in interference, acquisition and temporal alignment of a transmitted signal by a receiver can be the most fragile component of the link. In this paper, synchronization detection in the presence of interference for multiple-input multiple-output (MIMO) communication is discussed. Here, synchronization indicates signal acquisition and timing estimation at the receiver, and is formulated as a binary statistical hypothesis test. Transmit sequences from multiple antennas are received by multiple antennas in noisy environments with spatially correlated noise (interference). Flat-fading and frequency-selective channel models for both the interference and signal of interest are considered. By applying well-known multiple antenna approaches to the MIMO synchronization problem, a number of new synchronization test statistics are introduced. These test statistics are motivated by minimum-mean-square-error (MMSE) beamformers, generalized-likelihood ratio test (GLRT), least-squared (LS) channel estimation, and spatial invariance. Test statistics appropriate for orthogonal-frequency-division-multiplexing (OFDM) systems are considered, including test statistics that take advantage of cyclic prefixes and of pilot sequences within an OFDM symbol. Performances of various test statistics in terms of probability of missing detection for some probability of a false detection are shown to vary by multiple orders of magnitude in the presence of interference.

0 Bookmarks
 · 
47 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cyclic-delay diversity (CDD) schemes require only one inverse discrete Fourier transform (IDFT) operation at the transmitter. As a result, they provide a low-complexity means of increasing the transmission diversity in multiple-input multiple- output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. In this paper, we develop a novel timing synchronization method for CDD-OFDM systems. In our proposed method, the channel correlation between transmit antennas is exploited to enhance timing synchronization accuracy. The simulation results are performed to verify the superiority of the proposed timing synchronization method.
    Proceedings of the 74th IEEE Vehicular Technology Conference, VTC Fall 2011, 5-8 September 2011, San Francisco, CA, USA; 01/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: Distributed space-time transmit beamforming approaches potentially improve the throughput and robustness of wireless communications links. In this paper, we propose a distributed, space-time, transmit beamformer formulation that performs simultaneous data transmission and channel probing in the presence of interference. The difficulty is that the data signal corrupts the whitened channel estimate and leads to a loss in signal-to-interference and noise ratio. We examine this loss relative to the optimal solution and propose a diagonal loading technique to reduce the loss.
    Statistical Signal Processing Workshop (SSP), 2012 IEEE; 01/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: Maximal invariants for adaptive detection of a signal in unknown interference from multiple observations is derived. Given coherent samples from P sets of observations, it is shown that a maximal invariant statistic for the detection problem is a 2P × 1-dimensional vector comprising the eigenvalues of two Hermitian positive definite matrices obtained from the data set. Two invariant detectors, well known for P=1, are generalized for the case of multiple observations and closed form expressions for the probability of detection and probability of false alarm are derived along with the distributions of the signal-to-interference-plus-noise loss factors. Several novel invariant detectors are constructed from the maximal invariants and the receiver operating characteristics of the detectors compared.
    IEEE Transactions on Signal Processing 01/2013; 61(14):3607-3619. · 2.81 Impact Factor