In a relay system, a relay node (RN) may communicate with a donor base station (BS) via a backhaul link. For example, the RN may receive control information from the donor BS over the backhaul link. The control information may be transmitted by the donor BS using a specific aggregation level. The RN may decode the control information by monitoring search spaces associated with various aggregation levels. When two or more search spaces are overlapped, decoding candidates of different aggregation levels of the same starting control channel element (CCE) index may result in a successful control information decoding, when actual control information transmission may use only one of the aggregation levels. Such a possibility may result in ambiguous decoding of the control information. Certain aspects of the present disclosure generally relate to handling the ambiguous decoding.