Patent ID: 7873004

Claim:
A method for a User Equipment (UE) to receive control information through a Physical Downlink Control Channel (PDCCH), the method comprising: receiving, at the UE, control information from a base station through the PDCCH in units of Control Channel Element (CCE) aggregations, each of the CCE aggregations including at least one CCE in a control region of a specific subframe; and decoding the received control information in units of search space including a start position in the specific subframe, wherein the start position is one of a number of possible start positions and is determined by using a specific index; wherein the specific index is determined by performing a first modulo operation on a first resultant value using a first variable value “C,” such that the first resultant value is a first dividend and the first variable value “C” is a first divisor in the first modulo operation, and wherein the first variable value “C” corresponds to the number of possible start positions; and wherein the first resultant value is determined by performing a second modulo operation on an input value using a first constant value “D,” such that the input value is a second dividend and the first constant value “D” is a second divisor in the second modulo operation.