SFBC MIMO energy efficiency improvements of common packet schedulers for the long term evolution downlink

It is desirable that energy performance improvement is not realized at the expense of other network performance parameters. This paper investigates the trade off between energy efficiency, spectral efficiency and user QoS performance for a multi-cell multi-user radio access network. Specifically, the energy consumption ratio (ECR) and the spectral efficiency of several common frequency domain packet schedulers in a cellular E-UTRAN downlink are compared for both the SISO transmission mode and the 2x2 Alamouti Space Frequency Block Code (SFBC) MIMO transmission mode. It is well known that the 2x2 SFBC MIMO transmission mode is more spectrally efficient compared to the SISO transmission mode, however, the relationship between energy efficiency and spectral efficiency is undecided. It is shown that, for the E-UTRAN downlink with fixed transmission power, spectral efficiency improvement results into energy efficiency improvement. The effect of SFBC MIMO versus SISO on the user QoS performance is also studied. © 2011 IEEE.

Retail restructuring and consumer choice 1:long term local changes in consumer behaviour : Portsmouth 1980-2002

Over the last two decades fundamental changes have taken place in the global supply and local structure of provision of British food retailing. Consumer lifestyles have also changed markedly. Despite some important studies of local interactions between new retail developments and consumers, we argue in this paper that there is a critical need to gauge the cumulative effects of these changes on consumer behaviour over longer periods. In this, the first of two papers, we present the main findings of a study of the effects of long-term retail change on consumers at the local level. We provide in this paper an overview of the changing geography of retail provision and patterns of consumption at the local level. We contextualise the Portsmouth study area as a locality that typifies national changes in retail provision and consumer lifestyles; outline the main findings of two large-scale surveys of food shopping behaviour carried out in 1980 and 2002; and reveal the impacts of retail restructuring on consumer behaviour. We focus in particular on choice between stores at the local level and end by problematising our understanding of how consumers experience choice, emphasising the need for qualitative research. This issue is then dealt with in our complementary second paper, which explores choice within stores and how this relates to the broader spatial context.

Long-term drivers of broadband traffic in next-generation networks

This paper is concerned with long-term (20+ years) forecasting of broadband traffic in next-generation networks. Such long-term approach requires going beyond extrapolations of past traffic data while facing high uncertainty in predicting the future developments and facing the fact that, in 20 years, the current network technologies and architectures will be obsolete. Thus, "order of magnitude" upper bounds of upstream and downstream traffic are deemed to be good enough to facilitate such long-term forecasting. These bounds can be obtained by evaluating the limits of human sighting and assuming that these limits will be achieved by future services or, alternatively, by considering the contents transferred by bandwidth-demanding applications such as those using embedded interactive 3D video streaming. The traffic upper bounds are a good indication of the peak values and, subsequently, also of the future network capacity demands. Furthermore, the main drivers of traffic growth including multimedia as well as non-multimedia applications are identified. New disruptive applications and services are explored that can make good use of the large bandwidth provided by next-generation networks. The results can be used to identify monetization opportunities of future services and to map potential revenues for network operators. © 2014 The Author(s).