Minimum Energy Transmission Over a Wireless Channel With Deadline and Power Constraints

• Published in: IEEE transactions on automatic control 2009-12, Vol.54 (12), p.2841-2852
• Main Authors: Zafer, M., Modiano, E.
• Format: Article
• Language: English
• Subjects: Applied sciences; Channels; Computer science; control theory; systems; Computer systems and distributed systems. User interface; Costs; Deadline; energy; Energy conservation; Energy consumption; Energy efficiency; Exact sciences and technology; Expenditures; Fading; Lagrangian functions; Optimal control; Optimization; packet delay; Policies; Power consumption; Quality of service; quality of service (QoS); rate control; Simulation; Software; Stochastic processes; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Time-varying channels; Transmission and modulation (techniques and equipments); Transmitters; wireless
• ISSN: 0018-9286; 1558-2523
• DOI: 10.1109/TAC.2009.2034202

We consider optimal rate-control for energy-efficient transmission of data, over a time-varying channel, with packet-deadline constraints. Specifically, the problem scenario consists of a wireless transmitter with B units of data that must be transmitted by deadline T over a fading channel. The transmitter can control the transmission rate over time and the required instantaneous power depends on the chosen rate and the present channel condition, with limits on short-term average power consumption. The objective is to obtain the optimal rate-control policy that minimizes the total energy expenditure while ensuring that the deadline constraint is met. Using a continuous-time stochastic control formulation and a Lagrangian duality approach, we explicitly obtain the optimal policy and show that it possesses a very simple and intuitive form. Finally, we present an illustrative simulation example comparing the energy costs of the optimal policy with the full power policy.