Intrinsic measure of diversity gains in generalised distributed antenna systems with cooperative users

The diversity gains achievable in the generalised distributed antenna system with cooperative users (GDAS-CU) are considered. A GDAS-CU is comprised of M largely separated access points (APs) at one side of the link, and N geographically closed user terminals (UTs) at the other side. The UTs are collaborating together to enhance the system performance, where an idealised message sharing among the UTs is assumed. First, geometry-based network models are proposed to describe the topology of a GDAS-CU. The mean cross-correlation coefficients of signals received from non-collocated APs and UTs are calculated based on the network topology and the correlation models derived from the empirical data. The analysis is also extendable to more general scenarios where the APs are placed in a clustered form due to the constraints of street layout or building structure. Subsequently, a generalised signal attenuation model derived from several stochastic ray-tracing-based pathloss models is applied to describe the power-decaying pattern in urban built-up areas, where the GDAS-CU may be deployed. Armed with the cross-correlation and pathloss model preliminaries, an intrinsic measure of cooperative diversity obtainable from a GDAS-CU is then derived, which is the number of independent fading channels that can be averaged over to detect symbols. The proposed analytical framework would provide critical insight into the degree of possible performance improvement when combining multiple copies of the received signal in such systems.

Drawing the net: internet identification, internet use, and the image of internet users

Theory and research suggest that Internet identification may account for some of the gender divide in Internet use. Internet identification is a type of domain identification, and is inherently bound with images of those who use the Internet, a domain traditionally conceived as masculine. Combining the “draw an Internet user” test with an Internet identification scale, this study tests two hypotheses: participants drawing gender-concordant images will (i) identify with and (ii) use the Internet more than those drawing gender-discordant images. Participants were 371 students (121 males, 250 females) from three universities in the United Kingdom and Australia. The need to challenge masculinized images of the Internet is discussed.

Ethnic variations in the experiences of mental health service users in England: results of a national patient survey programme

Background: Minority ethnic groups in the UK are reported to have a poor experience of mental health services, but comparative information is scarce. Aims: To examine ethnic differences in patients’ experience of community mental health services. Method: Trusts providing mental health services in England conducted surveys in 2004 and 2005 of users of community mental health services. Multiple regression was used to examine ethnic differences in responses. Results: About 27 000 patients responded to each of the surveys, of whom 10% were of minority ethnic origin. In the 2004 survey, age, living alone, the 2004 survey, age, living alone, detention and hospital admissions were stronger predictors of patient experience than ethnicity. Self-reported mental health status had the strongest explanatory effect. In the 2005 survey, the main negative differences relative to the White British were for Asians. Conclusions: Ethnicity had a smaller effect on patient experience than other variables. Relative to the White British, the Black group did not report negative experiences whereas the Asian group were most likely to respond negatively. However, there is a need for improvements in services for minority ethnic groups, including access to talking therapies and better recording of ethnicity.