640 research outputs found
On the Degrees of freedom of the K-user MISO Interference Channel with imperfect delayed CSIT
This work investigates the degrees of freedom (DoF) of the K-user
multiple-input single-output (MISO) interference channel (IC) with imperfect
delayed channel state information at the transmitters (dCSIT). For this
setting, new DoF inner bonds are provided, and benchmarked with
cooperation-based outer bounds. The achievability result is based on a
precoding scheme that aligns the interfering received signals through time,
exploiting the concept of Retrospective Interference Alignment (RIA). The
proposed approach outperforms all previous known schemes. Furthermore, we study
the proposed scheme under channel estimation errors (CEE) on the reported
dCSIT, and derive a closed-form expression for the achievable DoF with
imperfect dCSIT.Comment: Draft version of the accepted manuscript at IEEE ICASSP 1
Retrospective Interference Alignment for the MIMO Interference Broadcast Channel
The degrees of freedom (DoF) of the multiple-input multiple-output (MIMO)
Interference Broadcast Channel (IBC) with 2 cells and 2 users per cell are
investigated when only delayed channel state information is available at the
transmitter side (delayed CSIT). Retrospective Interference Alignment has shown
the benefits in terms of DoF of exploiting delayed CSIT for interference,
broadcast and also for the IBC. However, previous works studying the IBC with
delayed CSIT do not exploit the fact that the users of each cell are served by
a common transmitter. This work presents a four-phase precoding strategy taking
this into consideration. Assuming that transmitters and receivers are equipped
with antennas, respectively, new DoF inner bounds are proposed,
outperforming the existing ones for .Comment: 1 copyright page + 5 paper pages + 3 appendix pages, Submitted to
IEEE ISIT 201
Achievable DoF-delay trade-offs for the K-user MIMO interference channel with delayed CSIT
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works.The degrees of freedom (DoFs) of the K-user multiple-input multiple-output (MIMO) interference channel are studied when perfect, but delayed channel state information is available at the transmitter side (delayed CSIT). Recent works have proposed schemes improving the DoF knowledge of the interference channel, but at the cost of developing transmission involving many channel uses (long delay), thus increasing the complexity at both transmitter and receiver side. This paper proposes three linear precoding strategies, limited to at most three phases, based on the concept of interference alignment, and built upon three main ingredients: delayed CSIT precoding, user scheduling, and redundancy transmission. In this respect, the interference alignment is realized by exploiting delayed CSIT to align the interference at the non-intended receivers along the space-time domain. Moreover, a new framework is proposed where the number of transmitted symbols and duration of the phases is obtained as the solution of a maximization problem, and enabling the introduction of complexity constraints, which allows deriving the achievable DoF as a function of the transmission delay, i.e., the achievable DoF-delay trade-off. Finally, the latter part of this paper settles that the assumption of time-varying channels common along all the literature on delayed CSIT is indeed unnecessary.Peer ReviewedPostprint (author's final draft
Del Misal Rico de Cisneros y de la Biblia Políglota Complutense o bien del manuscrito al impreso
Aunque de distinto signo y filiación, el Misal Rico (1504-1517) y la Biblia Políglota (1514-1517) se asocian al cardenal Cisneros. Son probablemente las más ambiciosas empresas librarias del siglo -el misal sin duda es la obra cumbre de la miniatura hispánica del XVI-. Esta excepcional secuencia de libros se presenta como una cadena de pausas y avances, tejiendo una imbricada trama en la que se cruzan estrategias religiosas, artísticas, políticas e ideológicas.The Misal Rico (1504-1517) and the Biblia Políglota (1514-1517), although of different sind and authorship, are both associated to Cardinal Cisneros. These works are probably the most ambicious book projects of the sixteenth century -the missal is without doubt the master piece of the Renaissance Hispanic Miniature-. The exceptional sequence of these two books weave an imbricated net in which religious, artistic, political and ideological strategies cross, shaping a complex chane of pauses and advancements
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