Optimization of Energy Efficiency for Uplink Wireless Information and Downlink Power Transfer System with Imperfect CSI

Table 1

Variables and their corresponding meanings.

Variable	Meaning
	Number of antennas
	Number of users
	The th user
	Length of one period time
	Channel estimation time portion
	Energy transfer time portion
	Information transmission time portion
	Channel matrix
	Source beamforming vector
	Pathloss factor
	Source transmitting power
	Harvested power at the th user
	Receiving storage conversion ratio
	Reserving energy portion for user
	The th user information transmitting power
	The th user information transmission time
	The th order identity matrix
diag{}	Diagonal matrix with elements
	Transpose of matrix
	Mathematical expectation