  In this paper, we propose a pricing mechanism for the uplink communication
cooperation to save the energy of mobile terminals (MTs) in wireless cellular
network. Under the uncertainties of the other MTs' channel and battery
conditions, a source MT in low battery level or bad channel condition is
allowed to select and pay another MT in proximity to help forward its data
package to the base station (BS). We formulate the source MT's pricing and load
sharing problem as an optimization problem to minimize its expected energy
cost. When the source MT cannot split its data package for a certain multimedia
application, we motivate the selected relay MT to forward the whole data
package by obtaining the optimal pricing through a dichotomous search
algorithm. When the source MT can split the data package, we jointly optimize
the pricing and load sharing with the relay MT and propose an alternating
optimization algorithm that achieves near-optimal solution. Extensive numerical
results are provided to show that our proposed pricing mechanism can
significantly decrease the source MT's expected energy cost, and load sharing
is more cost-efficient when the size of the data package is large and the
average number of helping MTs is small.
