This disclosure relates to aligning semi-persistent scheduling (SPS) uplink and downlink communications. In one embodiment, a cellular base station may select SPS parameters for a wireless device. The SPS parameters may include a subframe offset, a downlink SPS interval, and an uplink SPS interval. The subframe offset may indicate a subframe at which both an initial downlink subframe and an initial uplink subframe are scheduled. An indication of the SPS parameters may be transmitted to the UE. The wireless device and the cellular base station may perform uplink and downlink communication according to the SPS parameters.