Embodiments of the present disclosure describe methods, computer-readable media and system configurations for wireless communications. A method may include receiving a transmission of a series of symbols, including an index, and determining a plurality of configurations of a physical downlink channel based on the index. In various embodiments, the plurality of configurations of the physical downlink channel may include one or more antenna ports that are reserved for a reference signal. A relay node (RN) may include a processor and a memory storing a plurality of potential combinations of a plurality of configurations of a physical downlink channel. The processor may be configured to receive a transmission of a series of symbols, including an index, and match the index to one of the plurality of potential combinations. A donor evolved NodeB (DeNB) may be configured to encode such an index into a transmission. Other embodiments may be described and/or claimed.