Graduate School and Research Center in Digital Sciences

Network MIMO: Transmitters with no CSI can still be very useful

de Kerret, Paul; Gesbert, David

ISIT 2016, IEEE International Symposium on Information Theory July 10-15, 2016, Barcelona, Spain

In this paper we consider the Network MIMO channel under the so-called Distributed Channel State Information at the Transmitters (D-CSIT) configuration. In this setting, the precoder is designed in a distributed manner at each Transmitter (TX) on the basis of local versions of Channel State information (CSI) of various quality. Although the use of simple Zero-Forcing (ZF) was recently shown to reach the optimal DoF for a Broadcast Channel (BC) under noisy, yet centralized, CSI at the TX (CSIT), it can turn very inefficient when faced with D-CSIT: The number of Degrees-of-Freedom (DoF) achieved is then limited by the worst CSI accuracy across TXs. To circumvent this effect, we develop a new robust transmission scheme improving the DoF. A surprising result is uncovered by which, in the regime of so-called weak CSIT, the proposed scheme is shown to be DoF-optimal and to achieve a centralized outerbound consisting in the DoF of a genie-aided centralized setting in which the CSIT versions of all TXs are available everywhere. Building upon the insight obtained in the weak CSIT regime, we develop a general D-CSIT robust scheme for the 3-user case which improves over the DoF obtained by conventional robust approaches for any arbitrary CSIT configuration.

Document Doi Bibtex

Title:Network MIMO: Transmitters with no CSI can still be very useful
Department:Communication systems
Eurecom ref:4971
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Bibtex: @inproceedings{EURECOM+4971, doi = {}, year = {2016}, title = {{N}etwork {MIMO}: {T}ransmitters with no {CSI} can still be very useful}, author = {de {K}erret, {P}aul and {G}esbert, {D}avid}, booktitle = {{ISIT} 2016, {IEEE} {I}nternational {S}ymposium on {I}nformation {T}heory {J}uly 10-15, 2016, {B}arcelona, {S}pain}, address = {{B}arcelona, {SPAIN}}, month = {07}, url = {} }
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