Learn More
This paper examines a novel digital modulation/multiple access technique called Multi-Carrier Code Division Multiple Access (MC-CDMA) where each data symbol is transmitted at multiple narrowband subcarriers. Each subcarrier is encoded with a phase offset of 0 or π based on a spreading code. Analytical results are presented on the performance of this(More)
—IEEE 802.15.4 was developed to meet the needs for low-rate wireless communication. However, due to its low power, IEEE 802.15.4 is potentially vulnerable to interference by other wireless technologies having much higher power and working in the same Industrial, Scientific, and Medical (ISM) band such as IEEE 802.11b/g. The paper therefore focuses on the(More)
1 Abstract If C is a q-ary code of length n and a and b are two codewords, then c is called a descendant of a and b if c i 2 fa i ; b i g for i = 1; : : : ; n. We are interested in codes C with the property that, given any descendant c, one can always identify at least one of thèparent' codewords in C. We study bounds on F (n; q), the maximal cardinality of(More)
IEEE 802.15.4 Wireless Sensor Networks (WSNs) share the 2.4 GHz Industrial, Scientific, and Medical (ISM) license-free band with many other wireless technologies such as IEEE 802.11b/g Wireless Local Area Networks (WLANs). Because of the low-power, however, IEEE 802.15.4 WSNs are potentially vulnerable to the interference introduced(More)
In biometrics, a human being needs to be identified based on some characteristic physiological parameters. Often this recognition is part of some security system. Secure storage of reference data (i.e., user templates) of individuals is a key concern. It is undesirable that a dishonest verifier can misuse parameters that he obtains before or during a(More)
—In mobile reception, the reliability of orthogonal frequency division multiplexing (OFDM) is limited because of the time-varying nature of the channel. This causes intercarrier interference (ICI) and increases inaccuracies in channel tracking. In this paper, we model the ICI using derivatives of the channel amplitude. This allows us to design a relatively(More)
—In orthogonal frequency-division multiplexing, time variations of a multipath channel lead to a loss of orthogo-nality between the subcarriers, and thereby limit the achievable throughput. This paper proposes a general framework for a controlled removal of intercarrier interference (ICI) and channel acquisition. The core idea behind our method is to use a(More)