Provision of Maximum Delay Guarantee at Low Energy in a Multi-User Environment

In this work a simple scheduling scheme is proposed for wireless sensor networks in presence of a maximum tolerable delay constraint. The scheduler performs the dual task of scheduling the users experiencing high channel gains to minimize the energy consumption while at the same time, it takes into account the maximum allowed buffer length of each user to provide an upper bound on the maximum tolerable delay. The idea of a threshold depending on the buffer occupancy is proposed to schedule the users opportunistically unless the deadline for transmission is reached. A maximum delay guarantee is provided in the proposed scheme in addition to average delay guarantee at almost no additional energy cost. The results show that multilevel recursive optimization can minimize energy subject to maximum bounded delay for schedulers that empty the buffer.