Energy-based task load balancing in wireless sensor networks

Abstract

We investigate how to maximize network lifetime by devising a task assignment protocol that balances task load on sensors based on their remaining energy. First, we show that energy-unaware protocols can excessively assign tasks to a set of sensors more than others. Consequently, the energy of those heavily loaded sensors will be depleted much faster than lightly loaded ones. This results in reducing network density around heavily loaded sensors and eventually creates energy holes that isolate the network into separated islands. This kind of behavior has its negative impacts on network durability and reliability. To avoid these problems, we propose a management protocol that assigns tasks to sensors based on their remaining energy so that energy consumption is almost even among network sensors.

On prolonging network lifetime by adjusting sleep/awake cycles in wireless sensor networks

“…We also proposed energy aware task management protocol that assigns tasks to sensors based on their energy. This paper is in fact an extension of our previous work published in [1]. Particularly, we look into how we can achieve longer network lifetime by adjusting sensor sleep/awake cycles without affecting the network density.…”

“…After that, a fully distributed workforce selection mechanism is used to recruit required workforce. Since some of the ideas presented in [1] is very relevant to what is presented here, we thought it would be appropriate to summarize these ideas here, however the reader is highly encouraged to review our paper for more details. …”

“…To verify the performance of the proposed protocol, we built a simulator of the task management protocol described in [1]. We integrated task assignment with sleep/awake cycle adjustment as described in section V. The integration required adding another round to the basic workforce selection protocol to allow the evaluation of the minimum energy among awake sensors in addition to the original round needed by the basic protocol to evaluate the maximum energy among sensors.…”

“…The first protocol is "Energy-Neutral" and does not consider differences in sensors energy when assigning tasks to sensors. The second protocol is an integrated version of the task management protocol published in [1] with sleep/awake cycle adjustments. This protocol assigns tasks to sensors based on differences between sensors energy.…”

“…In a previous work [1], we showed how improper task assignment can result in severely uneven consumption of sensors energy due to excessively tasking a set of sensors more than others. Not only this can reduce network density in the spots near the locations of heavily loaded sensors, but also it can eventually create energy holes that isolate the network into disconnected islands.…”