This paper considers the problem of power allocation between the two senders in the multiple access
channel. Two power allocation criteria are developed. In particular, in the first criterion, the total
available power is allocated between the two users such that the two users have the same achievable rate.
In addition, the second criterion allocates the total available power such that the sum rate is maximized. In
addition, many numerical examples are shown to show the value of power allocation and also to compare
between the proposed criteria.