560 research outputs found
A Dynamic Clustering and Resource Allocation Algorithm for Downlink CoMP Systems with Multiple Antenna UEs
Coordinated multi-point (CoMP) schemes have been widely studied in the recent
years to tackle the inter-cell interference. In practice, latency and
throughput constraints on the backhaul allow the organization of only small
clusters of base stations (BSs) where joint processing (JP) can be implemented.
In this work we focus on downlink CoMP-JP with multiple antenna user equipments
(UEs) and propose a novel dynamic clustering algorithm. The additional degrees
of freedom at the UE can be used to suppress the residual interference by using
an interference rejection combiner (IRC) and allow a multistream transmission.
In our proposal we first define a set of candidate clusters depending on
long-term channel conditions. Then, in each time block, we develop a resource
allocation scheme by jointly optimizing transmitter and receiver where: a)
within each candidate cluster a weighted sum rate is estimated and then b) a
set of clusters is scheduled in order to maximize the system weighted sum rate.
Numerical results show that much higher rates are achieved when UEs are
equipped with multiple antennas. Moreover, as this performance improvement is
mainly due to the IRC, the gain achieved by the proposed approach with respect
to the non-cooperative scheme decreases by increasing the number of UE
antennas.Comment: 27 pages, 8 figure
Scientific Developments Connected with the Second Industrial Revolution: A. Baracca, S. Ruffo, and A. Russo, Scienza e Industria 1848–1915, 41 years later
The pioneering work, Scienza e Industria 1848–1915: Gli sviluppi scientifici connessi alla seconda rivoluzione industriale (Science and Industry 1848–1915: Scientific developments related to the second industrial revolution) by Angelo Baracca, Stefano Ruffo, and Arturo Russo is reproduced in this preprint. Published in Italian by Laterza in 1979, it is an unjustly forgotten treasure of a highly fertile and innovative period of the history of science. The introduction to the preprint describes the historical circumstances in which this book and the approach it proposes emerged. It covers a wide range of subjects, from the different ways in which the Second Industrial Revolution unfolded in Great Britain and in continental Europe to the upheaval in modern science, in particular in chemistry in the latter half of the nineteenth century and in physics at the beginning of the twentieth century. Although each of these themes has meanwhile become the subject of detailed historical investigations, the survey and overall picture that Scienza e Industria provides is still intriguing: it connects the new knowledge economy of the Second Industrial Revolution with the conceptual revolutions in modern physics by pointing to the mediatory role of chemistry
Indoor Massive MIMO Deployments for Uniformly High Wireless Capacity
Providing consistently high wireless capacity is becoming increasingly
important to support the applications required by future digital enterprises.
In this paper, we propose Eigen-direction-aware ZF (EDA-ZF) with partial
coordination among base stations (BSs) and distributed interference suppression
as a practical approach to achieve this objective. We compare our solution with
Zero Forcing (ZF), entailing neither BS coordination or inter-cell interference
mitigation, and Network MIMO (NeMIMO), where full BS coordination enables
centralized inter-cell interference management. We also evaluate the
performance of said schemes for three sub-6 GHz deployments with varying BS
densities -- sparse, intermediate, and dense -- all with fixed total number of
antennas and radiated power. Extensive simulations show that: (i) indoor
massive MIMO implementing the proposed EDA-ZF provides uniformly good rates for
all users; (ii) indoor network densification is detrimental unless full
coordination is implemented; (iii) deploying NeMIMO pays off under strong
outdoor interference, especially for cell-edge users
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