  In this paper, we consider the problem of minimizing the total transmission
cost for exchanging channel state information. We proposed a network coded
cooperative data exchange scheme, such that the total transmission cost is
minimized while each client can decode all the channel information held by all
other clients. In this paper, we first derive a necessary and sufficient
condition for a feasible transmission. Based on the derived condition, there
exists a feasible code design to guarantee that each client can decode the
complete information. We further formulate the problem of minimizing the total
transmission cost as an integer linear programming. Finally, we discuss the
probability that each client can decode the complete information with
distributed random linear network coding.
