An Upper Bound on the Sum Capacity of the Downlink Multicell Processing with Finite Backhaul Capacity

摘要

In this paper, we study upper bounds on the sum capacity of the downlinkmulticell processing model with finite backhaul capacity for the simple case of2 base stations and 2 mobile users. It is modelled as a two-user multipleaccess diamond channel. It consists of a first hop from the central processorto the base stations via orthogonal links of finite capacity, and the secondhop from the base stations to the mobile users via a Gaussian interferencechannel. The converse is derived using the converse tools of the multipleaccess diamond channel and that of the Gaussian MIMO broadcast channel. Throughnumerical results, it is shown that our upper bound improves upon the existingupper bound greatly in the medium backhaul capacity range, and as a result, thegap between the upper bounds and the sum rate of the time-sharing of the knownachievable schemes is significantly reduced.