New Algorithms for Blind Block Synchronization in Zero-Padding Systems

Blind channel identification using linear redundant filterbank precoders (LRP) has been studied extensively in the literature. Most methods are proposed based on the assumption that block synchronization is perfect. In practice, a blind block synchronization algorithm must be used to justify this assumption. This paper studies the blind block synchronization problem in systems using a zero-padding (ZP) precoder. A previously reported method is reviewed and a new approach for the problem is proposed. Generalized versions of both approaches are then developed using a parameter called repetition index. Simulation results show that when the repetition index is chosen to be greater than unity, the block synchronization error rate performance of the proposed algorithm has a significant improvement over the previously reported method

Blind block synchronization algorithms in cyclic prefix systems

In orthogonal frequency division multiplexing (OFDM) systems, symbol synchronization is a critical step for successful data transmission. While this task is done in most current systems by using training symbols, a few studies have been dedicated to solving the problem blindly, that is, where training symbols are not available. Blind symbol synchronization problem is especially important in many blind channel estimation algorithms in the literature which assume that OFDM symbol synchronization is perfect. In this paper, a broader version of the blind symbol synchronization problem is studied, namely, blind block synchronization in cyclic-prefix (CP) systems. The proposed algorithm for this broader problem covers the blind symbol synchronization problem in OFDM systems. Unlike previously reported algorithms which are based on obtaining sufficient statistics of received samples, the proposed algorithm is capable of identifying the correct block boundaries using much less received data in absence of noise. Simulation results of the proposed algorithm not only verify the declared property but also demonstrate improvement in accuracy of symbol synchronization over previously reported algorithms in presence of noise

New Blind Block Synchronization for Transceivers Using Redundant Precoders

This paper studies the blind block synchronization problem in block transmission systems using linear redundant precoders (LRP). Two commonly used LRP systems, namely, zero padding (ZP) and cyclic prefix (CP) systems, are considered in this paper. In particular, the block synchronization problem in CP systems is a broader version of timing synchronization problem in the popular orthogonal frequency division multiplexing (OFDM) systems. The proposed algorithms exploit the rank deficiency property of the matrix composed of received blocks when the block synchronization is perfect and use a parameter called repetition index which can be chosen as any positive integer. Theoretical results suggest advantages in blind block synchronization performances when using a large repetition index. Furthermore, unlike previously reported algorithms, which require a large amount of received data, the proposed methods, with properly chosen repetition indices, guarantee correct block synchronization in absence of noise using only two received blocks in ZP systems and three in CP systems. Computer simulations are conducted to evaluate the performances of the proposed algorithms and compare them with previously reported algorithms. Simulation results not only verify the capability of the proposed algorithms to work with limited received data but also show significant improvements in the block synchronization error rate performance of the proposed algorithms over previously reported algorithms

New Algorithms for Blind Block Synchronization in Zero-Padding Systems

Abstract-Blind channel identification using linear redundant filterbank precoders (LRP) has been studied extensively in the literature. Most methods are proposed based on the assumption that block synchronization is perfect. In practice, a blind block synchronization algorithm must be used to justify this assumption. This paper studies the blind block synchronization problem in systems using a zero-padding (ZP) precoder. A previously reported method is reviewed and anew approach for the problem is proposed. Generalized versions of both approaches are then developed using a parameter called repetition index. Simulation results show that when the repetition index is chosen to be greater than unity, the block synchronization error rate performance of the proposed algorithm has a significant improvement over the previously reported method.&apos