Reduced complexity closest point decoding algorithms for random lattices

Abstract—Closest point algorithms find wide applications in decoding block transmissions encountered with single- or multiuser communication links relying on a single or multiple antennas. Capitalizing on the random channel and noise models typically encountered in wireless communications, the sphere decoding algorithm (SDA) and related complexity-reducing techniques are approached in this paper from a probabilistic perspective. With both theoretical analysis and simulations, combining SDA with detection ordering is justified. A novel probabilistic search algorithm examining potential candidates in a descending probability order is derived and analyzed. Based on probabilistic search and an error-performance-oriented fast stopping criterion, a computationally efficient layered search is developed. Having comparable decoding complexity to the nulling–canceling (NC) algorithm with detection ordering, simulations confirm that the novel layered search achieves considerable error-performance enhancement. Index Terms—Closest point algorithm, Lenstra, Lenstra, and Lovasz (LLL) lattice reduction, multiuser detection, random lattice decoding, space–time, sphere decoding. I

Giannakis, “Orthogonal design of unitary constellations for uncoded and trellis coded non-coherent space-time systems

Abstract—We construct unitary noncoherent space–time constellations, which can be considered as a concatenation of a training blockwith an orthogonal design. With a simple construction, our constellations are easy to design, enjoy full antenna diversity, allow for a simplified maximum-likelihood (ML) detector, and achieve error performance comparable to existing designs that rely on computer search. To exploit the constellation structures and improve coding gains, we further pursue a trellis-coded modulation (TCM) approach. Based on the sequence pairwise error analysis, we identify two simple parameters to quantify the asymptotic error performance, which enables us to compare among different TCM schemes or uncoded alternatives. Index Terms—Fading channel, noncoherent, performance analysis, space–time (ST), trellis-coded modulation (TCM). I

Evaluation of the chemical composition and bioactivity of essential oils from Cinnamomum camphora (L.) J.Presl. (Lauraceae), Piper nigrum L. (Piperaceae) and Stemona japonica (Miq.) (Stemonaceae) against Oryzaephilus surinamensis (Linnaeus, 1758) (Coleoptera: Silvanidae)

Oryzaephilus surinamensis is a serious insect pest of many stored products. Repellency and fumigation tests were performed to manage it. Essential oils (EO) from three plants – Cinnamomum camphora, Piper nigrum and Stemona japonica – were tested on Oryzaephilus surinamensis in the laboratory. Repellency was tested on filter paper in Petri dishes at a concentration of 31.4 μg/cm2, and 20 adults (10 days old) were observed for repellency behaviour 12, 24, 48 and 96 hours after the bioassay without any food. Cinnamomum camphora EO was the strongest repellent (83.75 ± 1.83%), followed by the Piper nigrum and Stemona japonica EOs. The eggs were obtained by maintaining 20 individuals (males and females) for 24 h in a 100 mL glass jar containing 5 g of diet feed. To evaluate the effect of EO on the development of larvae and adults, a filter paper disc impregnated with 0.1 mL of EO was placed on the inner side of the lid of the jar containing the eggs and diet feed. After 40 days, the number of adults and larvae in the jar was counted. All three EOs exhibited bioactivity against the development of larvae and adults. A relatively low number of larvae and adults was recorded in Cinnamomum camphora, followed by Stemona japonica and Piper nigrum. Gas chromatography/mass spectrometry was used to identify the major compounds in the EOs. Further studies are recommended to evaluate their bioactivity against different insect pests in stored seeds