A chirp-based wideband spread spectrum modulation technique for WLAN applications

Abstract

A bstract-A high data-rate wideband chirp spread spectrum system for indoor communications is presented. We propose the use of chirp signals with the well known pulse compression technique to make the system extremely robust and therefore suitable for applications in industrial environment. By using rI4-DQPSK modulation of the chirp signals, overlapping &irp signals, and optimized chirp signal design we achieve data rates up to 70 Mbps. There is no need for sophis-chirp-based wideband (> 50 MHz) spread spectrum system which will be shown to be insensitive against nonidealities in the implementation (e.g. frequency offset, production tolerances, nonlinearities). As a consequence a very cheap realisation is possible. In our w ork theprocessing and generation of the needed chirp signals is done by means of surface acoustic mve (SAW) devices. They are well established in toda y's wireless communication products [4] due to their high performance and low cost. THEORYticated digital signal processing due to the use of surface acoustic wave (SAW) filters for the generation and filtering of the chirp signals. system imperfections like production tolerances, temperature drift, nonlinearities, and others are shown to be either negligible or can be easily handeled. Simulation results reveal that the limiting faccaused by multipath propagation.The presented spread spectrum communication system is based on the well known principle of pulse compression with linear chirp signals [5]. The representation of a linear chirp waveform is giwn as (1) tor for the data rate is in tersydol interference in the time f < < $ 7 where T > a (')> fo = 2, and p are the chirp duration, the envelope,the center frequency, and the chirp rate, respectively. The chirp

Chirp-based LPD/LPI underwater acoustic communications with code-time-frequency multidimensional spreading

“…Chirp modulation or linear frequency modulation (LFM) was first used in [13]. Since then, chirp signals have been used as a communication technology that can enable low data rate, robust, low-power (LPD/LPI) wireless communications on simple-design, lowcost transceivers in different applications including indoor wireless communications [14], multiuser applications [15,16], and WLAN [17] and WPAN [18] applications. Chirp signals also have been proposed in the UWA communications literature as highly reliable but low data rate alternatives [10,19,20].…”

Design and Simulation of a Chirp Pulse Compression Ultra-Wideband Communication System

“…The IEEE 802.15.4a Task Group has taken the CSS physical layer techniques as the criteria of standard physical layer, which can be used in either indoor environment within 60m or outdoor environment within 900m [5]. We simulated the variation of the designed CSS system's transmitting distances with the data rate, as shown Fig.…”

“…Moreover, the width of chirp signal can be compressed after having passed though the matched filter and the multipath effect can also be weakened. In recent years, many scholars have studied the UWB system based on chirp signals [1]- [5]. In this paper, on these bases, a further study on the chirp compressing technology has been made and the corresponding UWB radio communication system has been designed too.…”

Implementation of a high reliable chirp underwater acoustic modem

“…The use of chirp modulation (CM) for binary data communication was first proposed by Winkler [7].Then, it was used in digital communication. Recently, chirp signals have been widely considered for different purposes, such as multiuser applications [8]- [11], indoor wireless communication [12], WLAN applications [13]. Also, chirp signals have been widely used in underwater acoustic (UWA) communications [14]- [16].…”