In this paper, new classes of binary generalized cyclotomic sequences of period 2pm+1qn+1 are constructed. These sequences are balanced. We calculate the linear complexity of the constructed sequences with a simple method. The results show that the linear complexity of such sequences attains the maximum.

OFDM/offset-QAM (OFDM/OQAM) has been proven to be a promising multi-carrier transmission technique. However, carrier frequency offset (CFO) can lead to severe inter-carrier interference (ICI) and performance degradation. Meanwhile, channel estimation is also an important issue because of the intrinsic characteristics of OFDM/OQAM. In this paper, a novel pilot structure and a frequency-domain cross-correlation algorithm are proposed for the joint CFO and channel estimation. Analysis and simulation results validate the effectiveness of the proposed pilot structure and estimation algorithm.

In this paper, we propose a low-complexity, high-efficiency two-dimensional look-up table (2D LUT) for carrying out the sum-product algorithm in the decoding of low-density parity-check (LDPC) codes. Instead of employing adders for the core operation when updating check node messages, in the proposed scheme, the main term and correction factor of the core operation are successfully merged into a compact 2D LUT. Simulation results indicate that the proposed 2D LUT not only attains close-to-optimal bit error rate performance but also enjoys a low complexity advantage that is suitable for hardware implementation.

Recently the word-based stream ciphers have been the subject of a considerable amount of research. The theory of such stream ciphers requires the study of the complexity of a multisequence. Let S1, S2, . . . , Sm be m N-ary sequences of period T, i.e., a multisequence. The relationship between the joint N-adic complexity and the number of the nonzero columns of the generalized Fourier transform for the N-ary multisequence is determined which generalizes the well-known result about the joint linear complexity and the generalized Fourier transform for a multisequence to the case of the joint N-adic complexity.

The stability theory of stream ciphers plays an important role in designing good stream cipher systems. Two algorithms are presented, to determine the optimal shift and the minimum linear complexity of the sequence, that differs from a given sequence over Fq with period qn-1 by one digit. We also describe how the linear complexity changes with respect to one digit differing from a given sequence.

For battery-powered electronic products, one way to extend battery life is to use a versatile step-up/step-down DC-DC converter. A new versatile step-up/step-down switched-capacitor-based converter structure is proposed, and its efficiency is analyzed. In the step-down case, the efficiency is the same as, or even better than the efficiency of linear regulators.