We consider the differential sum rule for the effective scattering rate 1/t(v) and optical conductivity s1(v) in a dirty BCS superconductor, for arbitrary ratio of the superconducting gap D and the normal state constant damping rate 1/t . We show that if t is independent of T, the area under 1/t(v) does not change between the normal and the superconducting states, i.e., there exists an exact di...

Recently, researchers showed that dirty paper coding (DPC) is the optimal transmission strategy for multiple-input multiple-output broadcast channels (MIMO-BC). In this paper, we study how to determine the maximum weighted sum of DPC rates through solving the maximum weighted sum rate problem of the dual MIMO multiple access channel (MIMO-MAC) with a sum power constraint. We first simplify the ...

This letter considers the weighted sum-rate maximization (WSRMax) problem in downlink multicell multiuser orthogonal frequency-division multiplexing system. The WSRMax problem under per base station transmit power constraint is known to be NP-hard, and the optimal solution is computationally very expensive. We propose two lesscomplex suboptimal convex approximated solutions which are based on s...

Joint processing of multiple communication flows in wireless systems has given rise to a number of novel transmission techniques, notably the two-way relaying based on wireless network coding. Recently, a related set of techniques has emerged, termed coordinated direct and relay (CDR) transmissions, where the constellation of traffic flows is more general than the two-way. Regardless of the act...