  This paper studies the performance of a wireless data network using
energy-efficient power control techniques when different multiple access
schemes, namely direct-sequence code division multiple access (DS-CDMA) and
impulse-radio ultrawideband (IR-UWB), are considered. Due to the large
bandwidth of the system, the multipath channel is assumed to be
frequency-selective. By making use of noncooperative game-theoretic models and
large-system analysis tools, explicit expressions for the achieved utilities at
the Nash equilibrium are derived in terms of the network parameters. A measure
of the loss of DS-CDMA with respect to IR-UWB is proposed, which proves
substantial equivalence between the two schemes. Simulation results are
provided to validate the analysis.
