In this paper, we introduce the slow frequency hopping (SFH) technique to the multicarrier (MC) code-division multiple-access (CDMA) systems for overlay situations. Using lower chip rate, which results in a narrower spectrum for each carrier and hopping the signal in frequency, the MC direct sequence (DS)/SFH system achieves better performance than the MC DS CDMA system in most cases, especiall...

In this paper we present an interference analysis which reveals capacity reserves for a hierarchical GSM radio network. In the investigated concept a low-power Cordless Telephony System reuses the frequencies of a cellular GSM system based on Total Frequency Hopping (T-FH) multiple access. Based on a novel simulation method, which considers the dynamics of a T-FH cellular network, we present re...

We consider a distributed power control scheme in a Spread Spectrum (SS) wireless ad hoc network, in which each user announces a price that reflects his current interference level. Given these prices, we present an asynchronous distributed algorithm for updating power levels, and provide conditions under which this algorithm converges to an optimal power allocation. We relate this algorithm to ...

This paper develops an analytical model for characterizing the coexistence interference in the unlicensed industrial, scientific and medical (ISM) bands, based on radio frequency measurement results in the 2.4 GHz ISM band. The modeling approach presented here offers a simple methodology for profiling the interference from devices occupying a common spectrum. Outage performance using the interf...

In this paper, we present a graph-based model for analyzing interference between two frequency hopping systems for wireless communication. Informally, frequency hopping means that successive packets are transmitted on different frequencies from a pseudo-random sequence. The frequency band occupied by a packet may be narrow or wide. Our model is based on the concept of probabilistic graphs, wher...

This paper presents a beamforming technique for the reception of frequency hopping (FH) modulated signals, which takes advantage of their inherent frequency diversity. This technique, based on a code reference beamformer, requires neither temporal nor spatial a priori reference and allows continuous self-calibration of the array. The proposed framework is composed of two di!erent stages. The "r...

A Generalized Frequency Hopping (GFH) OFDMA system is developed in this paper as a structured long code DS-CDMA system in order to bridge frequency hopped multi-carrier transmissions with long code DS-CDMA. Through judicious code design, multiuser interference is eliminated deterministically in the presence of unknown frequency-selective multipath channels. Thanks to frequency hopping, no singl...

A filter-bank-based narrowband interference detection and suppression method is developed and its performance is studied in a spread spectrum system. The use of an efficient, complex, critically decimated perfect reconstruction filter bank with a highly selective subband filter prototype, in combination with a newly developed excision algorithm, offers a solution with efficient implementation a...

Jamming attacks have been studied as wireless security threats disrupting reliable RF communication in a wireless network. Existing countermeasures often make use of spread-spectrum techniques such as Frequency Hopping Spread Spectrum and Direct Sequence Spread Spectrum [3]. Communication parties rely on a pre-shared common key (hopping sequence or spread code) which is unknown to the jammer, t...

Convolutionally encoded M-ary quadrature amplitude modulation (M-QAM) systems operated over multidimensional channels, for example dual-polarized radio systems, are considered in this paper. We have derived upper bounds on the average bit-error probability for 4QAM (QPSK) with conventional convolutional coding by means of a truncated union bound technique and averaging over the cross-polarizati...