A Low-Complexity Joint Time Synchronization and Channel Estimation Scheme for Orthogonal Frequency Division Multiplexing Systems

On joint fine time adjustment and channel estimation for OFDM systems

“…The special periodic autocorrelation matrix of the MOS, which is an identity matrix, also makes the mathematical form of the CIR estimate in [6] become equivalent to the crosscorrelation function between the received training sequence and the MOS. Note that the thresholds used for the first channel tap selection in [6]- [8] are not optimized, and they must be determined via time-consuming simulations. Recently, an optimized threshold for the first channel tap selection was derived in [9].…”

“…In [7], a more theoretical joint approach using the maximum-likelihood (ML) principle was derived, where the same threshold factor was utilized for the first channel tap selection. Recently, Wang and Wang [8] presented a training sequence that is composed of a modulatable orthogonal sequence (MOS) [10] attached by both cyclic prefix and postfix. It can be viewed as a special case of the training sequence described in [6] with only two repetitive parts and an all positive sign pattern.…”

Optimized joint timing synchronization and channel estimation for communications systems with multiple transmit antennas

“…This paper develops a joint timing synchronization and channel estimation algorithm suitable for downlink MIMO networks based on a time-domain training sequence arrangement in the short-range wireless transmission environment. Unlike the previous works [9][10][11][12][13]17,18], this paper not only introduces the use of sliding observation vector in timing synchronization phase but also applies the minimum mean squared error (MMSE) criterion to perform fine time adjustment. In this paper, we first obtain a coarse timing offset using the cross-correlation function outputs based on the proposed training sequences at each receive antenna and then apply the generalized maximum-likelihood (ML) algorithm to find the advanced timing, relative timing indices, and the corresponding CIR estimates.…”

“…However, compared with the single carrier systems, OFDM systems are much more sensitive to synchronization errors [5]. Several approaches have been proposed to address this problem [6][7][8][9][10][11][12][13][14]. In addition, the performance of multiple-input signal processing depends on the amount of channel information.…”

“…Various techniques based on training sequences have been proposed to obtain accurate synchronization and channel estimation [9][10][11][12][13][14][15][16][17][18][19]. In [15], a training sequence arrangement based on modulated orthogonal sequences (MOS) for MIMO-OFDM systems was proposed to synchronize different transmit antennas.…”