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Interference Alignment and the Degrees of Freedom of Wireless X Networks.
- Source :
-
IEEE Transactions on Information Theory . Sep2009, Vol. 55 Issue 9, p3893-3908. 16p. 6 Diagrams, 1 Graph. - Publication Year :
- 2009
-
Abstract
- We explore the degrees of freedom of M x N user wireless X networks, i.e., networks of M transmitters and N receivers where every transmitter has an independent message for every receiver. We derive a general outer bound on the degrees of freedom region of these networks. When all nodes have a single antenna and all channel coefficients vary in time or frequency, we show that the total number of degrees of freedom of the X network is equal to MN/M+N-1 per orthogonal time and frequency dimension. Achievability is proved by constructing interference alignment schemes for X networks that can come arbitrarily close to the outer bound on degrees of freedom. For the case where either M = 2 or N = 2 we find that the degrees of freedom characterization also provides a capacity approximation that is accurate to within O(1). For these cases the degrees of freedom outer bound is exactly achievable. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00189448
- Volume :
- 55
- Issue :
- 9
- Database :
- Academic Search Index
- Journal :
- IEEE Transactions on Information Theory
- Publication Type :
- Academic Journal
- Accession number :
- 44226633
- Full Text :
- https://doi.org/10.1109/TIT.2009.2025541