Dual-Mode Chirp Spread Spectrum Modulation

A Novel Chirp Modulation Spread Spectrum Technique for Multiple Access

This paper proposes a new approach in chirp modulation spread spectrum (CMSS). A good selection of the parameters of the linear chirps, which are used in chirp modulation, combined with antipodal signaling significantly reduces the multiple access interference (MAI) even for small time-bandwidth products. This makes such systems attractive for efficient spread spectrum multiple access. Equal en...

Precise Location Technology Based on Chirp Spread Spectrum

This article introduces chirp spread spectrum technology (CSS for short) and optimized location algorithm. Symmetric double-sided two way ranging technique (SDS– TWR for short) is applied to improve accuracy and range of measurement. Linear frequency modulation ranging technology utilizes protocols combining CSMA / CA and TDMA, and adjusts dynamically transmission rate and frame length accordin...

Spread-Spectrum Multi-h Modulation

Direct sequence spread spectrum Walsh-QPSK modulation

In this paper we present Walsh-quadrature phase-shift keying (Walsh-QPSK) pseudonoise (PN) modulation schemes for both coherent and noncoherent direct-sequence code-division multiple-access (DS-CDMA) systems, wherein the PN spreading sequences for in-phase and quadrature data in a conventional QPSK PN modulation scheme are coded by Walsh sequences indexed by a special rule to reduce the envelop...

Spatial image watermarking using spread spectrum modulation

The paper presents low cost spatial image watermarking scheme where inherent anti jamming and interference rejection property of spread spectrum modulation is utilized to provide robustness against image distortions and malicious attempts to remove or tamper with the watermark. The use of error correction code allows a trade-off between degree of robustness and embedding rate for a given attack...