Joint beamforming, power control and scheduling for multihop wireless networks

In this paper, we propose a joint beamforming, power control and link scheduling algorithm for multihop wireless networks. We consider a multihop wireless network of nodes where each node is equipped with a transmit antenna array and a receive antenna array. A prespecified average data rate requirement is given for each link, as well as the channel matrix between each transmit array and receive array. The objective is to meet the required data rates while minimizing the average transmission power expended, subject to a peak transmission power constraint per node. While beamforming, power control and link scheduling need to be jointly optimized to achieve this goal, our proposed duality approach enables us to decouple these mechanisms. A simple, link-optimal, multiple-input and multiple-output (MIMO) beamforming algorithm is derived. Also, it is demonstrated that a simple 2 level (On-Off) power control suffices for the most energy efficient networking. Numerical examples suggests that while a TDMA scheduling is optimal for a low traffic demand, we need to schedule more simultaneous transmissions as the traffic load increases.