US Patent 8724636 Methods of reliably sending control signal

Downlink PDCCH is communicated in a manner that mitigates a UE from decoding the PDCCH on multiple aggregation levels. Ambiguous payload sizes are identified and modified through zero padding with one or more bits based on the payload size. Aggregation level scrambling sequences can be generated such that a receiving UE can accurately identify the aggregation level on which to decode the PDCCH. Indicator bits that signal the aggregation level to a UE can also be included in the PDCCH.