  In this work, we investigate the problem of mitigating interference between
so called antenna domains of a cloud radio access network (C-RAN). In contrast
to previous work, we turn to an approach utilizing primarily the optimal
assignment of users to central processors in a C-RAN deployment. We formulate
this user assignment problem as an integer optimization problem, and propose an
iterative algorithm for obtaining a solution. Motivated by the lack of
optimality guarantees on such solutions, we opt to find lower bounds on the
problem, and the resulting interference leakage in the network. We thus derive
the corresponding Dantzig-Wolfe decomposition, formulate the dual problem, and
show that the former offers a tighter bound than the latter. We highlight the
fact that the bounds in question consist of linear problems with an exponential
number of variables, and adapt the column generation method for solving them.
In addition to shedding light on the tightness of the bounds in question, our
numerical results show significant sum-rate gains over several comparison
schemes. Moreover, the proposed scheme delivers similar performance as W-MMSE
with a significantly lower complexity (around 10 times less).
