In this paper, a new iterative grid selection strategy for the Time-Mapped Harmonic Balance (TMHB) method is presented. This strategy is referred to the adaptive grid methods, which tracks the rapid transitions and constructs a smooth time-map function. The theoretical analysis and simulation results of this grid selection strategy are presented. The results demonstrate that this new strategy improves the numerical stability of the TMHB method and achieves accurate results based on the improved TMHB method.

The current reversible data embedding techniques can be divided into 2 categories: those developed by the untreated original images and those developed by the images treated via the lossy compression as the reversible target. So far, there has not been any literature discussing the issue of the reversible data embedding action finished during the lossless still image compression. Our method employs Chuang and Lin's simplified lossless image compression method to develop a reversible data embedding technique. Our method successfully embeds the secret data in the lossless image compression codes and have the secret data reversed to the original image as the secret data are retrieved wherefrom. According to the experimental results, the proposed method performs well on the embedding capacity and compression effects.

A 10-bit TFT-LCD column driver with hybrid DACs is proposed. The data conversion is implemented by an R-DAC and a C-DAC, which are used for the MSB and LSB data conversions, respectively. The simulated results show that the DAC exhibits the maximum DNL and INL of 0.28 LSB and 0.35 LSB, respectively. The settling time is within 4,us. The areas for one R-DAC and one C-DAC are 0.438 x 1.063 mm(2) and 0.207 x 0.11 mm(2). respectively.

We propose an adaptive rank-estimation method for the additive white or colored Gaussian noise model. The main contribution of this paper has three parts. (1) We investigate the rank mismatch problem in the group-blind multiuser detector of Wang and Host-Madsen (see IEEE J. Select. Areas Commun., vol.17, p.1971-1984, Nov. 1999), and find that underestimating the rank causes significant performance degradation, whereas, rank overestimation can achieve performance gain in the low signal-to-noise-ratio (SNR) region. However, rank overestimation can lead to inaccurate channel estimation, which degrades the detector performance significantly in the high SNR region. (2) We propose a heuristic criterion for initial rank estimation which is robust for nonwhite noise cases. (3) In order to mitigate the rank mismatch problem, we introduce a hypothesis testing criterion for rank and signal subspace decisions, which selects the most probable rank for the group-blind detectors. Simulation results show that the performance of the group-blind detector using this adaptive rank estimation algorithm is comparable to the group-blind with perfect knowledge of the rank, and even better in the low-to-medium SNR region.

We develop a novel multistage group-blind multiuser detection technique for reverse link in multi-cell direct sequence (DS) code-division multiple access (CDMA) systems. This approach fully utilizes all known users' information, performs interference cancellation (IC) to suppress the interferers within the cell, and exploits blind adaptive decision-directed (DD) MMSE detector to suppress the inter-cell interference. This process can be made iterative and in the multistage process, the tentative decision bits from DD-MMSE detectors can be fed back to the IC part to make interference regeneration more accurate. A simplified RLS (SRLS) algorithm is derived particularly for DD-MMSE detectors and steady-state SIR performance of the SRLS algorithm is analyzed. It is shown that the proposed detector with SRLS algorithm is sufficient to perform accurate multiuser detection and has significant performance gain over that of the pure blind detectors and the non-blind detectors for the given scenario. Moreover, compared with the conventional RLS algorithm, the SRLS algorithm has lower computational complexity and the convergence speed is faster. We also develop two group-blind channel estimation methods to estimate the effective signature waveforms in multipath fading channel. It is seen that the group-blind channel estimation methods using updated received signal correlation matrix can effectively combat the mismatch problem faced by pure blind detectors.

The blind multiuser detection techniques in DS-CDMA systems mainly deal with the demodulation of a desired user's data with the prior knowledge of only the signature sequence of that user. However, in the CDMA reverse link, the base station knows the signature sequences of users in its cell, but has no knowledge of interfering users from other cells. In this paper, we develop a class of novel semi-blind technique for multiuser detection in such a scenario. This approach fully utilizes all known users' information, performs multistage parallel or serial interference cancellation to suppress the interferers within the cell, and exploits a blind adaptive decision-feedback MMSE detector to suppress the inter-cell interference. The performance of the proposed detector is found to have significantly better performance than that of the purely blind detectors and the non-blind detectors.