In this letter, a constant-amplitude biorthogonal multicode (CABM) modulation is proposed. The proposed modulation is a biorthogonal modulation scheme that employs a constant-amplitude transmission of multicode signals by introducing a simple constant-amplitude coding scheme with redundant bits. The proposed CABM modulation can provide bandwidth efficiency up to the level (i.e., 9/16) of constant-amplitude orthogonal multicode (CAOM) modulation. We prove that our encoding scheme proposed in this letter provides this constant amplitude property. The bit-error rate (BER) performance expressions and the union bounds of the proposed CABM modulation and demodulation pairs are derived analytically. The results of the computer simulation and theoretical analysis performed show that the BER performance and the hardware complexity of the proposed CABM modulation are significantly better than those of a CAOM modulation

In this paper, a multi-coded variable spreading gain (MC-VSG) CDMA system employing a binary transmission of MC signals by introducing a level clipper, termed MC-VSG BNet system, is proposed for a possible candidate of wireless personal area network (WPAN) and 3G cellular applications. With an emphasis on the MC-VSG BNet physical layer and the system performance, we address the concise specification of the MC-VSG BNet system. From the receiver performance based on simulation results, in addition to simple receiver structure, an acceptable performance degradation of the MC-VSG BNet system over the existing DS/CDMA system is observed, while guaranteeing an high bit rate transmission.

A multi-coded CDMA system employing a variable spreading gain (VSG) approach is proposed for high-rate applications, which is based on two algorithms for selecting the multi-code set. From the simulation results, in addition to a simple receiver structure thanks to level clipping, the multi-coded VSG CDMA system provides a high bit rate transmission, while maintaining an acceptable performance degradation of the multi-coded VSG CDMA system over the existing DS-CDMA system.

This paper considers a channel estimation technique in a wireless personal area network (WPAN) system with complementary code keying (CCK) signaling over multipath fading channels. The performance of the proposed coherent detector is compared with that of a noncoherent detector, and a significant improvement of performance is observed in terms of the bit error probability.

We present a coarse frequency-offset synchronization technique for an OFDM-based transmission system with an emphasis on the Eureka-147 DAB receiver. The proposed frequency-offset synchronization algorithm using two defined correlation functions is shown to have high robustness against a large range of symbol timing offset with a moderate implementational complexity.

This paper describes an adaptive timing synchronization scheme and DC-offset compensation technique for a short-ranged Bluetooth system. The synchronization scheme estimates the variance of the partial-band interference, which is utilized for the trigger threshold value of the inquiry scan and page scan states, while DC-offset compensation scheme is designed using the access codes which are known to each Bluetooth device. Numerical results show the proposed synchronization algorithm is robust to the partial-band noise interference and of low complexity. Also, the new DC-offset compensation method shows more reliable estimation ability of DC-offset than the existing method without extra hardware burdens.