  In this paper, we consider the problem of power control for sum rate
maximization on multiple interfering links (TX-RX pairs)under sum power
constraint. We consider a single frequency network, where all pairs are
operating in same frequency band,thereby creating interference for each other.
We study the power allocation problem for sum rate maximization with and
without QoS requirements on individual links. When the objective is only sum
rate maximization without QoS guarantees, we develop an analytic solution to
decide optimal power allocation for two TX-RX pair problem. We also develop a
low complexity iterative algorithm for three TX-RX pair problem. For a generic
N>3 TX-RX pair problem, we develop two low-complexity sub-optimal power
allocation algorithms. The first algorithm is based on the idea of making
clusters of two or three TX-RX pairs and then leverage the power allocation
results obtained for two and three TX-RX pair problems. The second algorithm is
developed by using a high SINR approximation and this algorithm can also be
implemented in a distributed manner by individual TXs. We then consider the
same problem but with additional QoS guarantees for individual links. We again
develop an analytic solution for two TX-RX pair problem, and a distributed
algorithm for N>2 TX-RX pairs.
