the following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the present invention as defined by the claims and their equivalents . it includes various specific details to assist in that understanding but these are to be regarded as merely exemplary . accordingly , those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein may be made without departing from the scope and spirit of the invention . also , descriptions of well - known functions and constructions are omitted for clarity and conciseness . the terms and words used in the following description and claims are not limited to the bibliographical meanings , but , are merely used by the inventor to enable a clear and consistent understanding of the invention . accordingly , it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents . it is to be understood that the singular forms “ a ,” “ an ,” and “ the ” include plural referents unless the context clearly dictates otherwise . thus , for example , reference to “ a component surface ” includes reference to one or more of such surfaces . by the term “ substantially ” it is meant that the recited characteristic , parameter , or value need not be achieved exactly , but that deviations or variations , including for example , tolerances , measurement error , measurement accuracy limitations and other factors known to those of skill in the art , may occur in amounts that do not preclude the effect the characteristic was intended to provide . a way to generate and transmit / receive an s - sch for distinguishing a cell identification ( id ) in an institute of electrical and electronics engineers ( ieee ) 802 . 16m wireless communication system using an orthogonal frequency division multiple access ( ofdma ) scheme according to an exemplary embodiment of the present invention is proposed below . an exemplary structure of the ieee 802 . 16 in wireless communication system and a function of the s - sch are described below . fig3 is a diagram illustrating a base station ( bs ) and a mobile station ( ms ) of an ieee 802 . 16m wireless communication system according to an exemplary embodiment of the present invention referring to fig3 , in order for the ieee 802 . 16m ms 300 and the ieee 802 . 16m bs 310 to perform communication , the ieee 802 . 16m ms 300 has to acquire a cell id of the ieee 802 . 16m bs 310 through an s - sch signal transmitted by the ieee 802 . 16m bs 310 . here , the cell id includes a segment id . fig4 is a diagram illustrating positions of a primary sch ( p - sch ) and a secondary sch ( s - sch ) in an ieee 802 . 16m frame structure according to an exemplary embodiment of the present invention . referring to fig4 , in the ieee 802 . 16m frame structure , a super - frame has a time interval of 20 msec , and includes four frames each having a time interval of 5 msec . in an exemplary implementation , one p - sch symbol and three s - sch symbols may be positioned at intervals of 5 msec within one super - frame . the p - sch symbol is positioned within a super - frame header ( sfh ). here , although the p - sch symbol and the s - sch symbols are changed in number and position , it is undoubted that the proposal of the exemplary embodiment of the present invention is substantially identically applicable . a method for determining a subcarrier set corresponding to each segment id according to an exemplary embodiment of the present invention is described below . in an exemplary embodiment of the present invention , a length ( n ssch ) of a sequence for an s - sch is varied depending on a size of fft . the length ( n ssch ) of the sequence for the s - sch is equal to ‘ 144 ’ at a 512 - fft size , ‘ 288 ’ at a 1024 - fft size , and ‘ 576 ’ at a 2048 - fft size , respectively . the subcarrier set corresponding to each segment id is determined in equation 1 below : in equation 1 , ‘ sschcarrierset n ’ denotes an n - th subcarrier set , and ‘ n ’ denotes an index of a subcarrier set corresponding to a segment id and has a value of ‘ 0 ’, ‘ 1 ’, or ‘ 2 ’. assuming that there exist all three segments and each of the segments is expressed as ‘ segment 0 ’, ‘ segment 1 ’, or ‘ segment 2 ’, ‘ segment 0 ’ uses a subcarrier set ( sschcarrierset 0 ), ‘ segment 1 ’ uses a subcarrier set ( sschcarrierset 1 ), and ‘ segment 2 ’ uses a subcarrier set ( sschcarrierset 2 ). ‘ k ’ denotes a miming index having a value of ‘ 0 ’ to ‘ n ssch − 1 ’ depending on an fft size . a position of a direct current ( dc ) subcarrier in the subcarrier set is equal to ‘ 256 ’ at a 512 - fft size , ‘ 512 ’ at a 1024 - fft size , and ‘ 1024 ’ at a 2048 - fft size , respectively . fig5 , 6 , and 7 each are diagrams illustrating subcarrier sets each corresponding to segment ids at a 512 - fft size , a 1024 - fft size , and a 2048 - fft size according to an exemplary embodiment of the present invention . as illustrated in fig5 , 6 , and 7 , in the left and right regions centering on a dc subcarrier , subcarrier sets each corresponding to segments are comprised of subcarriers each having three intervals . near the dc subcarrier , a subcarrier set is comprised of subcarriers each having four intervals . a description is made below in detail by way of an example with respect to fig5 . at a 512 - fft size , a subcarrier set ( sschcarrierset 0 ) used in a ‘ segment 0 ’ has subcarrier indexes of ‘ 40 ’, ‘ 43 ’, ‘ 46 ’, ‘ 49 ’, . . . , ‘ 247 ’, ‘ 250 ’, ‘ 253 ’, ‘ 257 ’, ‘ 260 ’, ‘ 263 ’, . . . , ‘ 464 ’, ‘ 467 ’, and ‘ 470 ’. that is , in each of the left and right regions centering on a dc subcarrier index of ‘ 256 ’, the subcarrier set ( sschcarrierset o ) is comprised of subcarriers whose indexes increase by ‘ 3 ’. an interval between the subcarrier indexes of ‘ 253 ’ and ‘ 257 ’ near the dc subcarrier is equal to ‘ 4 ’. if a subcarrier set is determined as above , a three - time repetition pattern of the ieee 802 . 16e sch of the related art does not appear in a time domain . this feature is advantageous in that , in a coexistence mode in which an ieee 802 . 16m bs supports all of an ieee 802 . 16e ms and an ieee 802 . 16m ms , there exists only one type of symbol in which a three - time repetition pattern appears in a time domain and thus , each ms easily acquires timing synchronization . a method for determining a sequence corresponding to a cell id according to an exemplary embodiment of the present invention is described below . an exemplary embodiment of the present invention proposes to use all of 768 cell ids ( idcell ). a value of the cell id has a range of ‘ 0 ’ to ‘ 767 ’, and is determined by a segment id ( n ) and a running index ( idx ) as in equation 2 below . here , the segment id ( n ) has a value of ‘ 0 ’, ‘ 1 ’, or ‘ 2 ’, and the limning index ( idx ) has a value of ‘ 0 ’ to ‘ 255 ’. an s - sch sequence corresponding to the cell id determined through equation 2 above is configured using eight sequence blocks ( s 0 , s 1 , . . . , s 7 ). lengths of sequences included in each sequence block ( s 0 , s 1 , . . . , s 7 ) are equal to ‘ 72 ’. fig8 is a diagram illustrating an arrangement of each sequence block in a frequency domain depending on an fft size according to an exemplary embodiment of the present invention . referring to fig8 , in the case of a 512 - fft size , a sequence corresponding to a running index ( idx ) is sequentially selected from sequence blocks s 0 and s 1 , and the sequentially selected sequence is modulated into a power - boosted bpsk signal and is sequentially mapped to a subcarrier set corresponding to a segment id ( n ). in the case of a 1024 - fft size , a sequence corresponding to a running index ( idx ) is sequentially selected from sequence blocks ( s 2 , s 0 , s 1 , and s 3 ), and the sequentially selected sequence is modulated into a power - boosted bpsk signal and is sequentially mapped to a subcarrier set corresponding to a segment id ( n ). in the case of a 2048 - fft size , a sequence corresponding to a running index ( idx ) is sequentially selected in sequence blocks ( s 4 , s 5 , s 2 , s 0 , s 1 , s 3 , s 6 , and s 7 ), and the sequentially selected sequence is modulated into a power - boosted bpsk signal and is sequentially mapped to a subcarrier set corresponding to a segment id ( n ). a structure of fig8 in which s - sch signals are overlapped depending on a frequency bandwidth is referred to as a scalable structure . as such , an s - sch signal is comprised of sequences having a feature of scalability for a variety of fft sizes and thus , there is an advantage that an s - sch may support a variety of mss each supporting different bandwidths . table 1 below is a hexadecimal expression of an example of a sequence corresponding to a running index ( idx ) by sequence block . a length of each sequence is equal to ‘ 72 ’. in an exemplary implementation , the number of cell ids used may be equal to ‘ 768 ’. however , in case that the number of cell ids used is less than or is greater than ‘ 768 ’, a part or the whole of sequences of table 1 may be used . fig9 is a graph illustrating a papr of an s - sch signal corresponding to a cell id at each fft size according to an exemplary embodiment of the present invention . in fig9 , a horizontal axis denotes a running index ( idx ) constituting a cell id , and a vertical axis denotes a papr of an s - sch signal corresponding to the running index ( idx ). s - sch signals corresponding to three different cell ids having the same ‘ idx ’ but having different segment ids ( n ) have the same papr . in the case of a 512 - fft size , the maximum papr is equal to 6 . 27 db . in the case of a 1024 - fft size , the maximum papr is equal to 6 . 74 db . in the case of a 2048 - fft size , the maximum papr is equal to 7 . 06 db . as such , an s - sch symbol corresponding to a cell id has a very low papr and thus , an exemplary embodiment of the present invention may efficiently boost a transmit power when transmitting the s - sch symbol . an operation of an exemplary embodiment of the present invention based on the aforementioned description is described below in detail . fig1 is a block diagram illustrating a construction of a transmitter for transmitting an s - sch in an ieee 802 . 16m wireless communication system according to an exemplary embodiment of the present invention . as illustrated in fig1 , the transmitter includes a sequence generator 1000 ; a modulator 1002 , a subcarrier mapper 1004 , an ifft operator 1006 , a cyclic prefix ( cp ) adder 1008 , a digital to analog converter ( dac ) 1010 , and a radio frequency ( rf ) transmitter 1012 . referring to fig1 , the sequence generator 1000 generates a sequence dependent on a cell id from an upper controller ( not shown ). for example , the sequence generator 1000 includes a memory table such as table 1 above , and may acquire a sequence dependent on an input cell id , from the memory table . for another example , the sequence generator 1000 stores only a sequence dependent on a cell id corresponding to a bs , and may generate the stored sequence under control of the upper controller ( not shown ). the modulator 1002 modulates the sequence from the sequence generator 1000 according to a determined modulation scheme . for example , the modulator 1002 modulates the sequence into a power - boosted bpsk signal . the subcarrier mapper 1004 maps the modulated sequence from the modulator 1002 to subcarriers of a subcarrier set corresponding to a segment id . for example , the subcarrier set may be configured as in fig5 , 6 , or 7 described above depending on an fft size and a segment id . the ifft operator 1006 ifft - operates a signal mapped to subcarriers by the subcarrier mapper 1004 and outputs time domain sample data . the cp adder 1008 adds a guard interval ( e . g ., a cp ) to the sample data from the ifft operator 1006 and generates an s - sch signal ( or an s - sch symbol ). here , the ifft operator 1006 and the cp adder 1008 may be constructed as one ofdm modulator . the dac 1010 converts the s - sch symbol from the cp adder 1008 into an analog signal . the rf transmitter 1012 converts the baseband analog signal from the dac 1010 into an rf signal and transmits the rf signal through an antenna . on the other hand , an ms acquires a cell id using an s - sch signal received from a bs . at this time , the ms may acquire the segment id by measuring a receive power on a per - segment basis , and may acquire a running index ( idx ) through sequence detection in a frequency domain from a receive signal of a subcarrier set corresponding to the acquired segment id . fig1 is a block diagram illustrating a construction of a receiver for receiving an s - sch in an ieee 802 . 16 in wireless communication system according to an exemplary embodiment of the present invention . as illustrated in fig1 , the receiver includes an rf receiver 1100 , an analog to digital converter ( adc ) 1102 , a cp eliminator 1104 , an fft operator 1106 , a subcarrier extractor 1108 , a demodulator 1110 , and a sequence demodulator 1112 . referring to fig1 , the rf receiver 1100 converts an rf signal received from an antenna into a baseband analog signal . the adc 1102 samples the baseband analog signal from the rf receiver 1100 and converts the sampled analog signal into a digital signal the cp eliminator 1104 eliminates a guard interval that is inserted into the signal from the adc 1102 . the fft operator 1106 performs an fft operation for the signal from which the guard interval is eliminated by the cp eliminator 1104 , thereby outputting a frequency domain signal from a time domain signal . here , the cp eliminator 1104 and the fft operator 1106 may be constructed as one ofdm demodulator . the subcarrier extractor 1108 acquires a segment id by measuring a receive power on a per - segment basis , and extracts only signals of a subcarrier set corresponding to the acquired segment id , from the frequency domain signal from the fft operator 1106 . the demodulator 1110 demodulates the signals of the subcarrier set extracted by the subcarrier extractor 1108 , in a method corresponding to a modulation method used in the modulator 1002 . the sequence demodulator 1112 includes the same memory table as table 1 above , determines a correlation value between a sequence detected by the demodulation of the demodulator 1110 and all sequences of the memory table , and determines a running index ( idx ) corresponding to a sequence having the maximum correlation value . also , the sequence demodulator 1112 outputs a cell id that , in equation 2 , is determined from the segment id already acquired and the running index ( idx ) determined through the correlation value determination . fig1 is a flow diagram illustrating a procedure for transmitting an s - sch in an ieee 802 . 16m wireless communication system according to an exemplary embodiment of the present invention . referring to fig1 , a transmitter ( i . e ., a bs ) generates a sequence dependent on its own cell id in step 1201 . at this time , the transmitter generates a sequence based on an fft size and table 1 above . in step 1203 , the transmitter modulates the sequence . for example , the transmitter may modulate the sequence into a power - boosted bpsk signal . in step 1205 , the transmitter maps the modulated sequence to subcarriers of a subcarrier set corresponding to a segment id of the cell id . at this time , the subcarrier set may be configured as shown in fig5 , 6 , or 7 depending on an fft size and a segment id . in step 1207 , the transmitter ofdm - modulates the subcarrier - mapped sequence and generates an s - sch signal ( i . e ., an s - sch symbol ). here , the ofdm modulation includes an ifft operation , a cp addition , etc . in step 1209 , the transmitter rf - processes and transmits the generated s - sch signal to an ms . at this time , the s - sch signal may be transmitted at the front sub - frame within a frame , and may be transmitted at determined time intervals . fig1 is a flow diagram illustrating a procedure for receiving an s - sch in an ieee 802 . 16m wireless communication system according to an exemplary embodiment of the present invention referring to fig1 , a receiver ( i . e ., an ms ) receives an s - sch signal from a bs in step 1301 . at this time , the s - sch signal may be received at the front sub - frame within a frame , and may be received at determined time intervals . in step 1303 , the receiver ofdm - demodulates the received s - sch signal . here , the ofdm demodulation includes a cp elimination , an fft operation , etc . in step 1305 , the receiver acquires a segment id by measuring a receive power on a per - segment basis , and extracts only signals of a subcarrier set corresponding to the acquired segment id , from the ofdm - demodulated signal . in step 1307 , the receiver demodulates the extracted signals of the subcarrier set in a method corresponding to a modulation method used in a bs , and detects a sequence . in step 1309 , the receiver determines correlation values between the sequence detected by the demodulation and all sequences of a memory table , and determines a running index ( idx ) corresponding to a sequence having the maximum correlation value . in step 1311 , the receiver determines a cell id through equation 2 above using the segment id already acquired and the running index ( idx ) determined through the correlation value determination . as described above , exemplary embodiments of the present invention proposes an s - sch for making cell id distinguishment possible in an ieee 802 . 16m wireless communication system . the exemplary embodiments of the present invention may advantageously support a variety of mss each supporting different bandwidths because the s - sch of the exemplary embodiments of the present invention includes sequences having a feature of scalability for a variety of fft sizes . also , the exemplary embodiments of the present invention may advantageously support a femto cell by supporting many cell ids . while the invention has been shown and described with reference to certain exemplary embodiments thereof , it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents .