Reiner Hoppe

Database correlation for positioning of mobile terminals in cellular networks using wave propagation models

Many new services for mobile radio networks rely on a precise location of the mobile terminal. Especially in urban environments, multipath propagation leads to very complex scenarios without line-of-sight between the mobile and the different base stations. In these situations, a location technique based on simple delay evaluations and/or GPS is not accurate enough or not applicable. In this paper, a database correlation method for the positioning of mobile terminals is presented which yields precise results in urban environments. The approach is based on propagation models utilized for the planning of mobile radio networks. The results of the propagation models during the planning process define a look-up-table. By evaluating the measured path losses and available propagation times between the mobile terminal and several base stations, the positions of mobile terminals in urban environments can reliably be predicted.

Small subfamily of olfactory receptor genes: structural features, expression pattern and genomic organization.

Olfactory receptors of the OR37 subfamily are characterized by distinct sequence features and are expressed in neurons segregated in a restricted area of the olfactory epithelium. In the present study, we have characterized the complement of OR37-like genes in the mouse. Five OR37-like genes were identified. They reside within only 60kb of DNA on chromosome 4. About 70kb distant from this cluster, two additional olfactory receptor genes are located, which are members of distinct receptor subfamilies. Phylogenetic analysis demonstrated that the two physically linked receptors are closely related to the OR37 subfamily. Studies of gene expression showed that both genes are also expressed in clustered neuron populations located in the typical OR37 region of the epithelium. These data suggest the involvement of locus-dependent mechanisms for the spatial control of OR gene expression.

Measurement of building penetration loss and propagation models for radio transmission into buildings

The investigation of radio transmission into buildings is getting more and more important. Models for the propagation into buildings enable the calculation of the indoor field strength coverage based on the given outdoor coverage. In order to develop and to calibrate such propagation models several measurements of the building penetration loss with different transmitter locations were undertaken and evaluated. Additionally, the empirical, semi-empirical and deterministic models we developed are presented in this paper.

Verifying path loss and delay spread predictions of a 3D ray tracing propagation model in urban environment

In this paper path loss and delay spread predictions of a 3D ray tracing software are compared to wideband radio channel measurements made in Helsinki city center. Measurements were carried out in the 2 GHz band by using a wideband radio channel sounder, which gives out complex channel impulse responses. Reference delay spreads were obtained from power delay profiles, and path losses were available after appropriate cable calibration measurements. Comparisons between measurement and propagation predictions were made in cases where a realistic directional BS antenna was placed (a) slightly below the rooftop level and (b) slightly above the rooftop level. For propagation modeling a fully 3D ray optical model was used.

Automatic optimization algorithms for the planning of wireless local area networks

The planning of WLAN infrastructures that supply large buildings or areas requires the consideration of many aspects and therefore is a difficult task if done manually. In this paper, a method is presented that allows one to optimize such networks automatically. The approach is based on predictions of the received power to account for the propagation conditions that have a major impact on the performance of WLANs. The optimization is applied to a set of possible locations where access points can be installed. Out of this set, a minimum selection of locations is made to meet the given requirements. These consist of the determination of areas with different priorities and the definition of further parameters. It not only takes into account the required coverage and capacity but also the interference situation. The arising co-channel interference is minimized by an appropriate assignment of the available carrier frequencies. The discussed approach may not find the global optimum in all cases, but it yields a suggestive result based on the locations defined by the network planner. Due to the very short computation time, different configurations can be analyzed very quickly.

Advanced ray‐optical wave propagation modelling for urban and indoor scenarios including wideband properties

Ray-optical propagation models are often utilized for the prediction of the field strength (and delay spread) in mobile radio networks. However, the practical usage of these deterministic models is limited by their high computational demands. A new method for the acceleration of ray-optical models is presented in this paper. It is based on a single preprocessing of the database in which the mutual visibility relations between the walls and the edges of the buildings are determined. The propagation model is implemented for urban and indoor scenarios, and comparisons with measurements show the gain in computation efficiency as well as in achieved prediction accuracy.

Measurements and 3D Ray Tracing Propagation Predictions of Channel Characteristics in Indoor Environments

In this paper path loss, delay and angular spread predictions of a 3D ray tracing propagation tool are compared to spatially resolved wideband radio channel measurements performed in a modern office building. Measurements were carried out in the 5 GHz band by using a wideband radio channel sounder, which gives out complex channel impulse responses. Reference rms delay spread and angular spreads at transmitter and receiver were obtained from SAGE processed super-resolution data, and path losses were available from sounder matched filter outputs after appropriate calibrations. Comparisons between propagation predictions and measurements were made in different indoor scenarios including office, lobby and cafeteria environments. For propagation modelling a full 3D ray optical model was used.

Evolution of the “OR37” Subfamily of Olfactory Receptors: A Cross-Species Comparison

Genes encoding the olfactory receptors of the “OR37” subfamily of the mouse are characterized by special features including a clustered expression pattern, assembly in two distinct gene clusters, and highly conserved putative promoter motifs. Mining the rat and dog databases revealed that these two species possess highly conserved clusters of OR37 genes at two syntenic genomic loci. In a prototherian mammal, the platypus (Ornithorhynchus anatinus), none of the characteristic OR37 genes were found. Examination of a metatherian mammal, the gray short-tailed opossum (Monodelphis domestica) revealed seven canonical OR37 genes, all phylogenetically related to cluster II genes and also organized similar to cluster II of eutherian species. In addition, their 5′ upstream regions comprised sequence motifs related to the putative regulatory sequences of cluster II genes. Typical cluster I OR37 genes were identified only in the eutherian mammals examined, including the evolutionary ancient anteater, wherein OR37 genes related to both clusters were present. Together, these results reveal novel information concerning the phylogenetic origin and important evolutionary steps of the mammalian-specific OR37 olfactory receptor family.

Organization and evolutionary relatedness of OR37 olfactory receptor genes in mouse and human.

We report a comprehensive comparative analysis of human and mouse olfactory receptor (OR) genes encoding OR37 subtypes to determine the repertoire, chromosomal organization, and relatedness of these genes. Two OR37 clusters were found in both mouse (chromosome 4) and human (chromosome 9); with five genes in cluster I and three (mouse) and seven genes (human) in cluster II. The pronounced diversity of noncoding sequence regions in both genomic loci indicates a long-term coexistence of the two clusters and the genes within the clusters. In contrast, the coding regions, particularly of genes in cluster I, showed remarkably high sequence identity, a feature quite unique for OR genes. The conservation of only the coding sequences indicates that OR37 may be under negative selection pressure and suggests that the OR37 receptor family may be tuned to recognize distinct sets of signaling molecules. A comparison of mouse and human OR37 gene clusters revealed that genes in cluster I are highly related within each species whereas genes in cluster II are highly related across species. These data reflect a unique and complex evolutionary history of the OR37 family.

Dynamic simulator for studying WCDMA radio network performance

With the introduction of 3/sup rd/ generation cellular networks and their high bit rate services, new techniques in the field of radio network planning and dimensioning are required. This paper presents a simulation tool to support the planning process by analysing the performance of a given network constellation. Additionally, an example for a coverage and capacity analysis is given and simulation results gained with the dynamic simulator are discussed.