A novel approach is introduced for the design of a unique word (UW) for frame synchronization in time division multiplexing/time division multiple access (TDM/TDMA) systems. In particular, the UW symbols are distributed in each frame in a specific pattern in order to optimize the UW autocorrelation properties. The distribution patterns are scalable, since they preserve their autocorrelation properties under truncation. The resulting frame structure enables the use of several types of UWs, including the silent-UW (SUW) and the unit-UW (UUW), that are novel approaches for which the optimal Bayes detector is derived. An analytical performance characterization is presented along with comparisons with state-of-the-art alternatives. We show that SUW can significantly outperform the classic UW in the presence of frequency offsets or whenever data interference is the main impairment to cope with, i.e. at moderate to high signal to noise ratios. Interestingly, this performance improvement comes with the further advantage of a considerable complexity reduction. Hence UUW is shown to provide both performance improvement and complexity reduction.

A novel approach is introduced here for the design of the unique word (UW) to be inserted into TDM/TDMA systems for frame synchronization purposes. In particular, the UW is a very simple sequence of ones that are distributed along the frame in order to improve autocorrelation properties. The resulting UW is identified as unit-UW (U-UW). We show in this paper that U-UW leads to an optimum detector with very limited complexity, which does not require any multiplication. A fully analytical performance characterization is also presented and validated through numerical simulations

Frame synchronization and frequency estimation have historically been completely separate problems in digital receiver design. Here, a common avenue is discovered and transformed into practical algorithms. The proposed approach is based on the adoption of a differential post detection integration (DPDI) scheme for the acquisition of the unique word marking the beginning of the frame. The DPDI decision variable can indeed be used also for frequency estimation purposes, with very limited complexity. The adoption of a modular preamble structure with a two stage detector is also proposed to improve performance and optimize the detector structure. Performance is studied through simulations and analysis, providing closed form expressions for the estimation error variance. Both simulations and analysis show that the proposed joint approach is able to provide estimation performance close to the Cramer-Rao bound, as well as practically error-free frame synchronization, with very limited complexity

A novel approach is introduced for the design of the unique word (UW) to be inserted into TDM/TDMA systems for frame synchronization purposes. In particular, the UW is composed by all zero symbols that are distributed along the frame in order to improve the autocorrelation properties. The resulting UW is identified as silent-UW (S-UW). We show in this paper that S-UW leads to an optimum detector with very limited complexity, and with performance that can be significantly better than the classic UW in the presence of frequency offsets or at moderate to high signal-to-noise ratios. A fully analytical performance characterization is presented reporting also comparisons with state-of-the-art alternatives.