Science China Information Sciences

, Volume 53, Issue 5, pp 1034–1043 | Cite as

On degrees of freedom of the cellular network

Research Papers

Abstract

In this paper, we consider the capacity limits of the cellular network by modeling it as consisting of two mutually interfering multiple access channels with multiple antennas at each receiver (e.g., base station). By developing a tight outerbound as well as an achievable scheme which exploits the idea of interference alignment, we are able to exactly characterize the sum degrees of freedom (DoF) of the network when the channel coefficients are time- or frequency-varying, which equals \( \frac{{KM}} {{K + \min (M,K)}} \) (where M and K denote the number of receiver antennas and number of users in per cell, respectively) per cell. From the DoF result, it can be observed that in addition to the multi-user gain which has been reported for the network with single-antenna BSs, there also exists the multi-antenna gain in the cellular network. In particular, when the number of users is large, we can nearly achieve the interference-free DoF of a cellular network with multiple-antenna BSs, which is a somewhat surprising result.

Keywords

capacity degrees of freedom cellular network interference alignment interference channel MIMO 

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Copyright information

© Science China Press and Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  1. 1.Department of Electronics and Information EngineeringHuazhong University of Science and TechnologyWuhanChina
  2. 2.Division of Optical Network and Intelligent CommunicationWuhan National Laboratory for OptoelectronicsWuhanChina

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