Energy-Efficient Power Control for Contention-Based Synchronization in\n OFDMA Systems with Discrete Powers and Limited Feedback

This work derives a distributed and iterative algorithm by which mobile\nterminals can selfishly control their transmit powers during the\nsynchronization procedure specified by the IEEE 802.16m and the 3GPP-LTE\nstandards for orthogonal frequency-division multiple-access technologies. The\nproposed solution aims at maximizing the energy efficiency of the network and\nis derived on the basis of a finite noncooperative game in which the players\nhave discrete action sets of transmit powers. The set of Nash equilibria of the\ngame is investigated, and a distributed power control algorithm is proposed to\nachieve synchronization in an energy-efficient manner under the assumption that\nthe feedback from the base station is limited. Numerical results show that the\nproposed solution improves the energy efficiency as well as the timing\nestimation accuracy of the network compared to existing alternatives, while\nrequiring a reasonable amount of information to be exchanged on the return\nchannel.\n