Blind channel estimation for multi-rate multicarrier DS/CDMA communications

Multi-rate multicarrier DS/CDMA is a potentially attractive multiple access method for future wireless communications networks that must support multimedia, and thus multi-rate, traffic. Several receiver structures exist for single-rate multicarrier systems, but little has been reported on multi-rate multicarrier systems. Considering that high-performance detection such as coherent demodulation needs the explicit knowledge of the channel, based on the finite-length chip waveform truncation, this paper proposes a subspace-based scheme for timing and channel estimation in multi-rate multicarrier DS/CDMA systems, which is applicable to both multicode and variable spreading factor systems. The performance of the proposed scheme for these two multi-rate systems is validated via numerical simulations. The effects of the finite-length chip waveform truncation on the performance of the proposed scheme is also analyzed theoretically.

Blind adaptive channel estimation for dual-rate DS/CDMA signals

This letter proposes the subspace-based blind adaptive channel estimation algorithm for dual-rate quasi-synchronous DS/CDMA systems, which can operate at the low-rate (LR) or high-rate (HR) mode. Simulation results show that the proposed blind adaptive algorithm at the LR mode has a better performance than that at the HR mode, with the cost of an increasing computational complexity.

Blind channel estimation in multi-rate multicarrier DS-CDMA systems

Multi-rate multicarrier DS-CDMA is a potentially attractive multiple access method for future broadband wireless multimedia networks that must support integrated voice/data traffic. This paper proposes a subspace based channel estimation scheme for multi-rate multicarrier DS-CDMA, which is applicable to both multicode and variable spreading factor systems. The performance of the proposed scheme for these two multi-rate systems is compared via numerical simulations.

Blind channel estimation for dual-rate DS/CDMA

This paper proposes a subspace based blind adaptive channel estimation algorithm for dual-rate DS-CDMA systems, which can operate at the low-rate (LR) or high-rate (HR) mode. Simulation results show that the proposed blind adaptive algorithm at the LR mode has a better performance than that at the HR mode, with the cost of an increased computational complexity.

Blind channel acquisition and channel estimation for multi-rate multicarrier DS-CDMA communications

Multi-rate multicarrier DS-CDMA is a potentially attractive multiple access method for future wireless networks that must support multimedia, and thus multi-rate, traffic. Considering that high performance detection such as coherent demodulation needs the explicit knowledge of the channel, this paper proposes a subspace-based blind adaptive algorithm for timing acquisition and channel estimation in asynchronous multirate multicarrier DS-CDMA systems, which is applicable to both multicode and variable spreading factor systems.

Preliminary results on the non-thermal effects of 200-350 GHz radiation on the growth rate of S. cerevisiae cells in microcolonies

We report preliminary results from studies of biological effects induced by non-thermal levels of non-ionizing electromagnetic radiation. Exponentially growing Saccharomyces cerevisiae yeast cells grown on dry media were exposed to electromagnetic fields in the 200–350 GHz frequency range at low power density to observe possible non-thermal effects on the microcolony growth. Exposure to the electromagnetic field was conducted over 2.5 h. The data from exposure and control experiments were grouped into either large-, medium- or small-sized microcolonies to assist in the accurate assessment of growth. The three groups showed significant differences in growth between exposed and control microcolonies. A statistically significant enhanced growth rate was observed at 341 GHz. Growth rate was assessed every 30 min via time-lapse photography. Possible interaction mechanisms are discussed, taking into account Frohlich's hypothesis.

Measurement of apolipoprotein B-48 in the Svedberg flotation rate (Sf) > 400, Sf 60 – 400 and Sf 20 – 60 lipoprotein fractions reveals novel findings with respect to the effects of dietary fatty acids on triacylglycerol-rich lipoproteins in postmenopausal women

The present study was designed to examine whether the type of fat ingested in an initial test meal influences the response and density distribution of dietary-derived lipoproteins in the Svedberg flotation rate (Sf)>400, Sf 60 - 400 and Sf 20 - 60 lipoprotein fractions. A single-blind randomized within-subject crossover design was used to study the effects of palm oil, safflower oil, a mixture of fish and safflower oil, and olive oil on postprandial apolipoprotein (apo) B-48, retinyl ester and triacylglycerol responses in each lipoprotein fraction following an initial test meal containing one of the oils and a second standardized test meal. For all dietary oils, late postprandial (300min) concentrations of triacylglycerol and apo B-48 were significantly higher in the Sf 60 - 400 fraction than in the Sf>400 fraction (P<0.02). Significantly greater apo B-48 incremental areas under the curve (IAUCs) were also observed in the Sf 60 - 400 fraction than in the Sf>400 fraction following palm oil, safflower oil and olive oil (P<0.04), with a similar non-significant trend for fish/safflower oil. Olive oil resulted in a significantly greater apo B-48 IAUC in the Sf>400 fraction (P<0.02) than did any of the other dietary oils, as well as a tendency for a higher IAUC in the Sf 60 - 400 fraction compared with the palm, safflower and fish/safflower oils. In conclusion, we have found that the majority of intestinally derived lipoproteins present in the circulation following meals enriched with saturated, polyunsaturated or monounsaturated fatty acids are of the density and size of small chylomicrons and chylomicron remnants. Olive oil resulted in a greater apo B-48 response compared with the other dietary oils following sequential test meals, suggesting the formation of a greater number of small (Sf 60 - 400) and large (Sf>400) apo B-48-containing lipoproteins in response to this dietary oil.

Soil pH governs production rate of calcium carbonate secreted by the earthworm Lumbricus terrestris

Lumbricus terrestris earthworms exposed to 11 soils of contrasting properties produced, on average, 0.8 ± 0.1 mgCaCO3 earthworm−1 day−1 in the form of granules up to 2 mm in diameter. Production rate increased with soil pH (r2 = 0.68, p < 0.01). Earthworms could be a significant source of calcite in soils.