Patent ID: 8498646

Claim:
A method for transmitting, by a femto base station (BS), an interworking signal (IWS) which informs user equipments (UEs) around the femto BS of its presence in a wireless communication system, the method comprising: generating a sequence of a preamble including information on a frequency band on which the femto BS operates; mapping the IWS including the sequence of the preamble to a plurality of subcarriers of a frequency domain; and transmitting the IWS to the UEs through the plurality of subcarriers, wherein the IWS is mapped to a plurality of subcarriers positioned on a same orthogonal frequency division multiplexing (OFDM) symbol on a time domain, wherein a length of the IWS on the frequency domain is fixed regardless of bandwidth, and wherein the plurality of subcarriers is subcarriers excluding the subcarriers to which pilots are mapped and subcarriers adjacent to the subcarriers to which pilots are mapped.