Joint power control and spreading gain optimisation for minimising the energy consumption in CDMA based ad hoc networks

This paper addresses the impact of the spreading gain on the efficiency of mobile Ad Hoc networks using Code Division Multiple Access (CDMA) as a mode of transmission. In particular, we concentrate on the trade off between the increase in transmission datarate, hence decrease of transmission time, and the necessary power needed to reach acceptable levels of interference in the system. We formulate this trade off as an optimisation problem with associated constraints, where the cost function is the overall energy consumed inthe network and the constraints are the acceptable signal to interference ratio for each node. The solution to this optimisation problem provide optimal values for both the transmission spreading gains and powers that need to be allocated to each node in order to minimise the total energy consumption of the network.