  We investigate coordinated regularized zero-forcing precoding for limited
feedback multicell multiuser multiple-input single-output systems. We begin by
deriving an approximation to the expected signal-to-interference-plus-noise
ratio for the proposed scheme with perfect channel direction information (CDI)
at the base station (BS). We also derive an expected SINR approximation for
limited feedback systems with random vector quantization (RVQ) based codebook
CDI at the BS. Using the expected interference result for the RVQ based limited
feedback CDI, we propose an adaptive feedback bit allocation strategy to
minimize the expected interference by partitioning the total number of bits
between the serving and out-of-cell interfering channels. Numerical results
show that the proposed adaptive feedback bit allocation method offers a
spectral efficiency gain over the existing coordinated zero-forcing scheme.
