In some implementations, a method of wireless communications between a wireless communications network and wireless user equipment includes receiving, using a primary Time Division Duplex (TDD) configuration, data on a primary component carrier in a first frequency band. Using a secondary TDD configuration, data on a secondary component carrier is received in a second frequency band different from the first frequency band. A Hybrid Automatic Repeat Request (HARQ) for data received on the secondary component carrier is transmitted using a supplemental TDD configuration. A transmission or retransmission on the secondary component carrier uses a supplemental TDD configuration as well. The supplemental TDD configuration is different from the secondary TDD configuration. Furthermore, an uplink supplemental configuration may be different from a downlink supplemental configuration.