Exemplary communication apparatus comprising a MAC-layer processor configured to receive data for a downlink transmission to a first device; transmit a grant comprising resource allocations for the device to receive the data and to transmit a reception status for the data; and transmit the first grant and at least part of the data in a symbol. The grant can also be frequency-multiplexed with another grant to another device in the symbol, which can also be spatially multiplexed in streams directed to the respective devices. Other embodiments include determining a resource allocation for a device that encompasses resources previously allocated to at least one other device but comprises an indicator that such resource is unavailable to the device. Exemplary methods and computer-readable media can also be provided embodying one or more procedures the apparatus is configured to perform.