Transmission Rank Selection for Opportunistic Beamforming with Quality of Service Constraints

In this paper, we consider a multi-cell multi-user MISO broadcast channel. The system operates according to the opportunistic beamforming framework in a multi-cell environment with variable number of transmit beams (may alternatively be referred as the transmission rank) at each base station. The maximum number of co-scheduled users in a cell is equal to its transmission rank, thus increasing it will have the effect of increasing the multiplexing gain. However, this will simultaneously increase the amount of interference in the network, which will decrease the rate of communication. This paper focuses on optimally setting the transmission rank at each base station such that a set of Quality of Service (QoS) constraints, that will ensure a guaranteed minimum rate per beam at each base station, is not violated. Expressions representing the achievable region of transmission ranks are obtained considering different network settings. The achievable transmission rank region consists of all achievable transmission rank tuples that satisfy the QoS constraints. Numerical results are also presented to provide further insights on the feasibility problem.Comment: To appear in IEEE ICC 2014, Sydney, Australi

Outage Capacity of Opportunistic Beamforming with Random User Locations

This paper studies the outage capacity of a network consisting of a multitude of heterogenous mobile users, and operating according to the classical opportunistic beamforming framework. The base station is located at the center of the cell, which is modeled as a disk of finite radius. The random user locations are modeled using a homogenous spatial Poisson point process. The received signals are impaired by both fading and location dependent path loss. For this system, we first derive an expression for the beam outage probability. This expression holds for all path loss models that satisfy some mild conditions. Then, we focus on two specific path loss models (i.e., an unbounded model and a more realistic bounded one) to illustrate the applications of our results. In the large system limit where the cell radius tends to infinity, the beam outage capacity and its scaling behavior are derived for the selected specific path loss models. It is shown that the beam outage capacity scales logarithmically for the unbounded model. On the other hand, this scaling behavior becomes double logarithmic for the bounded model. Intuitive explanations are provided as to why we observe different scaling behavior for different path loss models. Numerical evaluations are performed to give further insights, and to illustrate the applicability of the outage capacity results even to a cell having a small finite radius.Comment: To appear in Globecom 2013, Atlanta, US

The Distribution of ESBL-Producing Enterobacteriaceae: Leicestershire UK Compared to Worldwide

open access articl

Preliminary Analysis of the Anti-biofilm Efficacy of Manuka Honey on Extended Spectrum Β-lactamase Producing Escherichia Coli Tem-3 and Klebsiella Pneumoniae Shv18, Associated with Urinary Tract Infections

open access articleUrinary Tract Infections (UTIs) are one of the most common infections in the UK and many other parts of the world. The prevalence of the Extended Spectrum β-Lactamases (ESBLs) producing UTIs, combined with their ability to form a bio film, has significantly risen and is limiting therapeutic options. This study investigated the anti-bio film activity of Manuka honey on two ESBL producing pathogens, Escherichia coli TEM-3 and Klebsiella pneumonia SHV18, commonly found in UTIs. The ESBL production was confirmed by the double disk synergy method used to confirm the ESBL production. The antibacterial activity of Manuka honey was determined using the agar well diffusion method. The Minimum Inhibitory Concentration (MIC) was established using serially diluted honey ranging from 50% to 1.56%. The effect of Manuka honey on the pathogen bio films was analysed using the Tissue Culture Plate method, with an established MIC and under 24h incubation with the honey. The results indicated that K. pneumonia SHV18 is a stronger bio film producer than E. coli TEM 3. 50% (w/v) MIC Manuka honey appears to fully prevent the plank tonic growth of both strains. A significant reduction of 81% of the E. coli TEM3 (p < 0.001) and 52% of the K. pneumonia SHV18 (p = 0.001) bio film biomass was observed. The E. coli bio films were found to be more sensitive to the 50% (w/v) honey dilution than those produced by K. pneumonia. The study indicated the anti-bio film potency of Manuka honey and its potential to become an alternative treatment for the ESBL producing pathogens associated with UTIs

Flood prone risk and amenity values: a spatial hedonic analysis

This study examines the impact of flood hazard zone location on residential property values. The study utilises data from over 2,000 private residential property sales occurred during 2006 in North Shore City, New Zealand. A spatial autoregressive hedonic model is developed to provide efficient estimates of the marginal effect of flood prone risks on property values. Our results suggest that a property located within a flood hazard zone sells for 4.3% less than an equivalent property located outside the flood hazard zone. Given the median house price, estimated discount associated with flood risks is approximately NZ$22,000.Flood hazard, Spatial hedonic, Amenity value, Land Economics/Use, Q15, Q51,

Poster Abstract: Network Coding with Limited Overhearing

CONETGINSEN