A medium access control (MAC) entity first computes an achievable rate region based on a total transmit power limit and a channel gain of each of a plurality of WTRUs. Next, the MAC entity selects an order of DPC among the WTRUs. A rate set for use in transmitting to the WTRUs is then selected, said rate set being within the computed achievable rate region. Then, based on the selected DPC order and rate set, a DPC entity performs DPC on a plurality of data streams intended for the plurality of WTRUs. If nested lattice-based DPC is utilized, rate compatibility is achieved by selecting proper nesting ratios corresponding to a desired data rate set. Otherwise, if binary-code based DPC is utilized, rate compatibility is achieved via selecting appropriate message input sizes for input to point-to-point coding units prior to performing DPC.