With the continued exponential growth of mobile traffic and the rise of diverse applications, the current LTE radio access network (RAN) architecture of cellular operators face mounting challenges. Current RAN suffers from insufficient radio resource coordination, inefficient infrastructure utilization, and inflexible data paths. We present the high level design of PRAN, which centralizes base stations' L1/L2 processing into a cluster of commodity servers. PRAN uses a flexible data path model to support new protocols; multiple base stations' L1/L2 processing tasks are scheduled on servers with performance guarantees; and a RAN scheduler coordinates the allocation of shared radio resources between operators and base stations. Our evaluation shows the feasibility of fast data path control and efficiency of resource pooling (a potential for a 30× reduction on resources).