ISIT 2015, IEEE International Symposium on Information Theory, June 14-19, 2015, Hong Kong, Hong-Kong
In the setting of the two-user single-input singleoutput X channel, recent works have explored the degrees-offreedom (DoF) limits in the presence of perfect channel state
information at the transmitter (CSIT), as well as in the presence of perfect-quality delayed CSIT. Our work shows that the same DoF-optimal performance -- previously associated to perfectquality current CSIT -- can in fact be achieved with current CSIT that is of imperfect quality. The work also shows that the DoF performance previously associated to perfect-quality delayed CSIT, can in fact be achieved in the presence of imperfect-quality delayed CSIT. These follow from the presented sum-DoF lower bound that bridges the gap -- as a function of the quality of delayed CSIT -- between the cases of having no feedback and having delayed feedback, and then another bound that bridges the DoF gap -- as a function of the quality of current CSIT -- between delayed and perfect current CSIT. The bounds are based on novel precoding schemes that are presented
here and which employ imperfect-quality current and/or delayed feedback to align interference in space and in time.
Type:
Conférence
City:
Hong Kong
Date:
2015-06-14
Department:
Systèmes de Communication
Eurecom Ref:
4588
Copyright:
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