  Centralized radio access network architectures consolidate the baseband
operation towards a cloud-based platform, thereby allowing for efficient
utilization of computing assets, effective inter-cell coordination, and
exploitation of global channel state information. This paper considers the
interplay between computational efficiency and data throughput that is
fundamental to centralized RAN. It introduces the concept of computational
outage in mobile networks, and applies it to the analysis of complexity
constrained dense centralized RAN networks. The framework is applied to
single-cell and multi-cell scenarios using parameters drawn from the LTE
standard. It is found that in computationally limited networks, the effective
throughput can be improved by using a computationally aware policy for
selecting the modulation and coding scheme, which sacrifices spectral
efficiency in order to reduce the computational outage probability. When
signals of multiple base stations are processed centrally, a computational
diversity benefit emerges, and the benefit grows with increasing user density.
