Reducing LTE Uplink Transmission Energy by Allocating Resources

The effect of physical resource block (PRB) allocation on an LTE modem´s transmit power and total modem energy consumption is examined. In this paper the uplink resource blocks are scheduled in either a Frequency Division Multiple Access (FDMA) or Time Division Multiple Access (TDMA) manner, to determine if low transmission power & long transmission time or high transmission power & short transmission time is most energy efficient. It is important to minimize the LTE modem´s energy consumption caused by uplink transmission because it affects phone battery time, and because researchers rarely focus on energy consumption when they optimize network controlled uplink transmission power parameters. Simulations based on a simple traffic model and a power consumption model show the TDMA scheme, where one user is allocated all 48 PRBs in a 10 MHz channel, is at least 24 % more energy efficient than the FDMA like approach with 8 PRBs per user. Furthermore the TDMA scheme decreases the average transmission time with minimum 24 %.