KR20050122664A - Apparatus and method for generating a preamble sequence for an adaptive antenna system in an orthogonal frequency division multiple access communication system - Google Patents

Abstract

In an orthogonal frequency division multiple access communication system having a plurality of cells, each of the plurality of cells having A segments, each of the cells having B subcarriers, for each of the cells: A downlink preamble sequences that are pre-allocated to each of the A segments are combined to generate A adaptive antenna system (AAS) sequences in the frequency domain, and A AAS preamble sequences in the frequency domain are generated. Inverse fast Fourier transform is performed to generate A AAS preamble sequences in the time domain.

Description

An apparatus and method for generating a preamble sequence for an adaptive antenna system in an orthogonal frequency division multiple access communication system {APPARATUS AND METHOD FOR GENERATING A PREAMBLE SEQUENCE FOR AN ADAPTIVE ANTENNA SYSTEM IN AN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS COMMUNICATION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to communication systems (hereinafter referred to as " OFDMA communication systems ") using orthogonal frequency division multiple access (OFDMA) schemes. An apparatus and method for generating a preamble sequence for applying an adaptive antenna system (AAS) scheme for minimizing intersector interference.

In the 4th Generation (hereinafter, referred to as '4G') communication system, users of services having various quality of service (hereinafter referred to as 'QoS') having a high transmission rate are used by users. Active research is underway to provide it. In particular, in 4G communication systems, broadband wireless such as a wireless local area network (hereinafter, referred to as a 'LAN') system and a wireless metropolitan area network (hereinafter, referred to as a 'MAN') system are used. Research is being actively conducted to support high-speed services in a form of guaranteeing mobility and quality of service (BoS) in a broadband wireless access (BWA) communication system. (Institute of Electrical and Electronics Engineers) 802.16a communication system and IEEE 802.16e communication system.

The IEEE 802.16a communication system and the IEEE 802.16e communication system are communication systems applying the OFDM / OFDMA scheme to support a broadband transmission network in a physical channel of the wireless MAN system. The IEEE 802.16a communication system is a system currently considering only a single cell structure and a state in which a subscriber station (SS) (hereinafter referred to as SS) is fixed, that is, no consideration of mobility of the SS is considered. . In contrast, the IEEE 802.16e communication system is a system considering the mobility of the SS in the IEEE 802.16a communication system, and the SS having the mobility is referred to as a mobile subscriber station (MSS). It will be called.

Meanwhile, in the IEEE 802.16e communication system, a multi-antenna is used to expand a cell service area, that is, increase overall capacity and provide space division multiple access (SDMA) for high-speed data transmission. SDMA 'method). In order to use the SDMA scheme, a preamble must be designed to accurately measure channel quality information (CQI) of each MSS. Meanwhile, the base station minimizes the interference between beams by using the correlation of the preambles, and accurately generates the beam with the channel state estimated for each MSS. It does not work so that the data can be decoded correctly.

That is, in order to allocate the same time and frequency resources to different MSSs, the base station generates a plurality of spatially separated beams, and in order to generate the beams for the downlink, an accurate uplink channel state is required. Information is needed. Accordingly, in a general IEEE 802.16e communication system, a downlink and uplink is transmitted to a downlink and uplink in order to support a preamble sequence (hereinafter, referred to as an 'AAS preamble sequence') in order to support the correct downlink and uplink. Link channel status information can be obtained. That is, the AAS preamble sequence is used to distinguish beams used in the IEEE 802.16e communication system when the AAS scheme is applied, and is used for channel estimation as necessary.

Next, a downlink frame structure in the case of using the AAS scheme in a general IEEE 802.16 communication system will be described with reference to FIG. 1.

FIG. 1 is a diagram schematically illustrating a downlink frame structure when the AAS scheme is used in a general IEEE 802.16e communication system.

Referring to FIG. 1, first, the downlink frame, that is, the DL sub-frame 100 is a non-AAS (hereinafter, referred to as a non-AAS) region. 110 and the AAS region 150. The non-AAS region 110 is a region targeting MSSs not supporting the AAS scheme, and the AAS region 150 is a region targeting MSSs supporting the AAS scheme. The AAS area 150 is an AAS Diversity Map Zone (hereinafter referred to as an AAS Diversity Map Zone) that includes information necessary to support the AAS scheme as well as a general burst. And 170.

The AAS diversity map region 170 includes a plurality of AAS preamble regions and a plurality of AAS downlink frame prefix (DLFP) regions (hereinafter referred to as 'AAS-DLFP'). do. The AAS preamble sequence is transmitted through the AAS preamble region, and control information associated with the corresponding AAS preamble sequence, that is, associated with the corresponding beam, is transmitted through the AAS-DLFP region. In this case, the control information transmitted through the AAS-DLFP region includes a downlink map (DL-MAP, hereinafter referred to as DL-MAP) region and an uplink map (UL-MAP, hereinafter 'UL'). Information compressed through the area).

As shown in FIG. 1, one AAS preamble region 151 occupies two OFDMA sub-channels in the frequency domain and one OFDMA symbol in the time-domain. Occupies a symbol duration. Here, the subchannel means a channel composed of at least one subcarrier, and the subcarriers constituting the subchannel may or may not be adjacent in the frequency domain. .

In addition, as shown in FIG. 1, one AAS-DLFP region 153 occupies two OFDMA subchannels in the frequency domain and occupies two OFDMA symbol intervals in the time domain. In the AAS-DLFP region 153, a quadrature phase shift keying (QPSK) scheme is applied as a modulation scheme, a 1/2 coding rate is applied as a coding rate, and transmitted twice by two repetitions. .

In FIG. 1, a downlink frame structure in the case of using the AAS scheme in a conventional IEEE 802.16e communication system has been described. Next, with reference to FIG. 2, a full usage of sub-channel is used in a typical IEEE 802.16 communication system (FUSC). -Channels, hereinafter referred to as 'FUSC' / Partial Usage of Sub-Channels (PUSC: hereinafter called 'PUSC') A permutation scheme is used, and the AAS scheme is used. The downlink frame structure in the case will be described.

FIG. 2 is a diagram schematically illustrating a downlink frame structure when a FUSC / PUSC exchange scheme is used in a general IEEE 802.16 communication system and an AAS scheme is used.

Referring to FIG. 2, first, the downlink frame, that is, the downlink subframe 200, includes a preamble region 210 and a frame control header (FCH) region (hereinafter, referred to as an 'FCH' region). 220, DL-MAP region 230, UL-MAP region 240, AAS Diversity Map Zone region 250, a plurality of AAS preamble regions 260-1, 270-1, 280-1, 290-1, Downlink burst regions corresponding to each of the plurality of AAS preamble regions 260-1, 270-1, 280-1, 290-1, that is, a first downlink burst region (DL Burst # 1) 260-2. ), A second downlink burst region (DL Burst # 2) 270-2, a third downlink burst region (DL Burst # 3) 280-2, and a fourth downlink burst region (DL Burst) # 4) 290-2.

As illustrated in FIG. 2, a PUSC exchange scheme is applied to the FCH region 220, the DL-MAP region 230, and the UL-MAP region 240. In addition, the FUSC / PUSC exchange scheme and the AAS scheme are applied to the remaining regions except for the preamble region 210, the FCH region 220, the DL-MAP region 230, and the UL-MAP region 240. do.

The preamble region 210 transmits a transmission / reception period, that is, a synchronization signal for synchronization acquisition between the base station and MSSs, that is, a preamble sequence. Hereinafter, for convenience of description, a preamble sequence that all MSSs of the IEEE 802.16 communication system must receive for synchronization with a base station will be referred to as a "downlink preamble sequence". In addition, basic information about a subchannel, ranging, a modulation scheme, etc. is transmitted through the FCH region 220. A DL_MAP message is transmitted through the DL_MAP region 230, and a UL_MAP message is transmitted through the UL_MAP region 230. Herein, the information elements included in the DL_MAP message and the UL_MAP message (IE) are not directly related, and thus detailed description thereof will be omitted.

In addition, as described with reference to FIG. 1, a plurality of AAS preambles and AAS-DLFPs corresponding to each of the AAS preambles are transmitted through the AAS Diversity Map Zone area 250. In this case, since the FUSC / PUSC exchange method is used, the AAS Diversity Map Zone area 250 occupies only 2 OFDMA subchannels as described with reference to FIG. 1. In particular, since the FUSC / PUSC exchange method is used, the AAS Diversity Map Zone area 250 is sequentially allocated from the subchannel having the maximum subchannel index.

Each of the AAS preamble sequences is transmitted through each of the AAS preamble regions 260-1, 270-1, 280-1, 290-1, and the first downlink burst region 260-2 to the fourth downlink burst region ( 290-2, bursts corresponding to each of the corresponding AAS preamble sequences are transmitted.

Meanwhile, the downlink frame structure illustrated in FIG. 2 has a structure in which the AAS Diversity Map Zone area 250 and the AAS preamble areas 260-1,270-1,280-1,290-1 are mixed, but the AAS Diversity Map Of course, it may have a structure that selectively exists only among the zone area 250 and the AAS preamble areas 260-1, 270-1, 280-1, 290-1.

In FIG. 2, the downlink frame structure when the FUSC / PUSC exchange method is used in the general IEEE 802.16 communication system and the AAS method has been described. Next, with reference to FIG. 3, the adaptive modulation in the general IEEE 802.16 communication system is described. And a downlink frame structure using an adaptive modulation and coding (AMC) switching scheme and an AAS scheme will be described.

FIG. 3 is a diagram schematically illustrating a downlink frame structure when the AMC switching scheme is used and the AAS scheme is used in a general IEEE 802.16 communication system.

Referring to FIG. 3, first, the downlink frame, that is, the downlink subframe 300 includes a preamble region 310, an FCH region 320, a DL-MAP region 330, and an UL-MAP region ( 340, the AAS Diversity Map Zone areas 350 and 355, the AAS preamble areas 360-1, 370-1, 380-1, 390-1, and the AAS preamble areas 360-1, 370-1, 380-1, 390- 1) Downlink burst regions corresponding to each, that is, the first downlink burst region 360-2, the second downlink burst region 370-2, and the third downlink burst region 380-2. And a fourth downlink burst region 390-2.

As illustrated in FIG. 3, a PUSC exchange scheme is applied to the FCH region 320, the DL-MAP region 330, and the UL-MAP region 340. In addition, the AMC exchange scheme and the AAS scheme are applied to the remaining regions except for the preamble region 310, the FCH region 320, the DL-MAP region 330, and the UL-MAP region 340.

Since the information transmitted through the areas shown in FIG. 3 is the same as the information transmitted through the areas described with reference to FIG. 2, a detailed description thereof will be omitted. However, in FIG. 3, since the AMC exchange method is used, two AAS Diversity Map Zone areas exist, that is, AAS Diversity Map Zone areas 350 and 355 exist. In particular, since the AMC switching scheme is used, the AAS Diversity Map Zone area 350 is allocated from subchannels spaced apart by a predetermined subchannel from a subchannel having a minimum subchannel index, and the AAS Diversity Map Zone area 355 ) Is allocated from subchannels spaced apart by preset subchannels from the subchannel having the maximum subchannel index.

In addition, the downlink frame structure illustrated in FIG. 3 has a structure in which the AAS Diversity Map Zone regions 350 and 355 and the AAS preamble regions 360-1, 370-1, 380-1, 390-1 are mixed, but the AAS Diversity It is of course possible to have a structure in which only Map Zone regions 350 and 355 and the AAS preamble regions 360-1, 370-1, 380-1, and 390-1 exist selectively.

3 illustrates the downlink frame structure when the AMC switching scheme is used in the conventional IEEE 802.16 communication system and the AAS scheme is described. Next, the IEEE 802.16 communication system is used with reference to FIGS. 4A through 4C. The downlink preamble sequence present will be described.

Before describing FIGS. 4A to 4C, it is assumed that the segment structure is the same as a general sector structure. The IEEE 802.16 communication system uses a total of 1702 subcarriers and uses one cell ( cell) is assumed to have a structure of a total of three segments, namely, segment 0, and a total of three segments of segment 1 and segment 2. In addition, it is assumed that the downlink preamble sequence has a length of 567. 4A to 4C have the same cell identifier (ID) (hereinafter, referred to as 'ID'), and only segment IDs are assumed to be different.

4A is a diagram schematically illustrating a downlink preamble sequence structure applied to segment 0 of a general IEEE 802.16 communication system.

Referring to FIG. 4A, each of elements of the downlink preamble sequence allocated to the segment 0 may have a result of calculating a corresponding subcarrier index of a total of 1702 subcarriers by% 3. Only subcarriers which are 0 are allocated one-to-one mapping. That is, the subcarrier 0, the subcarrier 3, the subcarrier 6, the subcarrier 9, ..., the subcarrier 1695, the subcarrier 1698, and the subcarrier 1701 are the 568 of the downlink preamble sequence of the segment 0 only. Elements are allocated. As a result, the sub-carrier set # 0 for the segment 0 is a set of subcarriers having a result of% 3 calculation is 0.

FIG. 4B schematically illustrates a downlink preamble sequence structure applied to segment 1 of a general IEEE 802.16 communication system.

Referring to FIG. 4B, each of the elements of the downlink preamble sequence allocated to the segment 1 as shown in FIG. 4B has a sub result of calculating a corresponding subcarrier index of a total of 1702 subcarriers by% 3. Only one-to-one mapped and assigned to carriers. That is, each of the 567 elements of the downlink preamble sequence of the segment 1 in subcarrier 1, subcarrier 4, subcarrier 7, subcarrier 10, ..., subcarrier 1696, and subcarrier 1699 are each Is assigned. As a result, subcarrier set # 1 for segment 1 becomes a set of subcarriers having a result of% 3.

4C schematically illustrates a downlink preamble sequence structure applied to segment 2 of a general IEEE 802.16 communication system.

Referring to FIG. 4C, each of the elements of the downlink preamble sequence allocated to the segment 2, as shown in FIG. 4C, has a sub result of calculating a corresponding subcarrier index of a total of 1702 subcarriers by% 3. Only one-to-one mapped and assigned to carriers. That is, each of the 567 elements of the downlink preamble sequence of the segment 2, each of subcarrier 2, subcarrier 5, subcarrier 8, subcarrier 11, ..., subcarrier 1697, and subcarrier 1700, respectively. Is assigned. As a result, subcarrier set # 2 for segment 2 is a set of subcarriers having a result of% 3.

Currently, the IEEE 802.16 communication system proposes a method of applying a downlink preamble sequence as an AAS preamble sequence. However, as described with reference to FIGS. 4A to 4C, when the downlink preamble sequence of the general IEEE 802.16 communication system considers all subcarriers in consideration of a segment structure, there are subcarriers to which elements of the downlink preamble sequence are not mapped. Done.

However, the number of subcarriers occupied in the AAS preamble region to which the AAS preamble sequence is transmitted is significantly smaller than that of the preamble region to which the downlink preamble sequence is transmitted. If each of the elements is mapped one-to-one, there is a problem that the detection probability of the AAS preamble sequence is significantly lowered.

For example, when the downlink preamble sequence as described with reference to FIGS. 4A and 4C is used as the AAS preamble sequence with a length as it is, the AAS is applied to subcarriers corresponding to 2/3 of the subcarriers of the entire AAS preamble region. The elements of the preamble sequence are not mapped at all. When the cross-correlation value is detected for the detection of the AAS preamble sequence, the maximum value of the cross-correlation value is correlated when elements of the AAS preamble sequence are mapped to all subcarriers of the AAS preamble region. Since it is limited to 1/3 of the correlation value, the detection probability of the AAS preamble sequence is significantly lowered.

Accordingly, there is a need for a method of generating and transmitting / receiving an AAS preamble sequence that can be accurately classified for each beam while maximizing detection probability in an IEEE 802.16 communication system.

Accordingly, an object of the present invention is to provide an apparatus and method for generating an AAS preamble sequence in an OFDMA communication system.

Another object of the present invention is to provide an apparatus and method for generating an AAS preamble sequence for maximizing detection probability in an OFDMA communication system.

Another object of the present invention is to provide an apparatus and method for generating an AAS preamble sequence using a downlink preamble sequence in an OFDMA communication system.

The apparatus of the present invention for achieving the above objects; An adaptive antenna system (AAS) in an orthogonal frequency division multiple access communication system having a plurality of cells, each of the plurality of cells having A segments, and each of the cells having B subcarriers. An apparatus for generating a sequence, the apparatus comprising: an AAS preamble sequence generator for generating A AAS preamble sequences in a frequency domain by combining A downlink preamble sequences previously allocated to each of the A segments for each of the cells; And an inverse fast Fourier transformer for inverse fast Fourier transforming the A AAS preamble sequences in the frequency domain into A AAS preamble sequences in the time domain.

The method of the present invention for achieving the above objects; An adaptive antenna system (AAS) in an orthogonal frequency division multiple access communication system having a plurality of cells, each of the plurality of cells having A segments, and each of the cells having B subcarriers. A method of generating a sequence, the method comprising: generating, for each of the cells, A downlink preamble sequences previously allocated to each of the A segments to generate A AAS preamble sequences in a frequency domain; And generating the A AAS preamble sequences in the time domain by performing inverse fast Fourier transform on the A AAS preamble sequences in the domain.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

The present invention relates to a communication system using an Orthogonal Frequency Division Multiple Access (OFDMA) scheme (hereinafter referred to as an "OFDMA communication system"), for example IEEE (Institute) preamble sequence (hereinafter referred to as "AAS") to support an adaptive antenna system (AAS) that maximizes detection probability in an 802.16e communication system (hereinafter, referred to as "AAS"). An apparatus and a method for generating the same are provided.

In addition, in the present invention, for convenience of description, only the downlink AAS preamble sequence is described as an example, but the AAS preamble sequence proposed in the present invention may be used not only as the downlink but also as an uplink AAS preamble sequence. Of course. In addition, the present invention proposes a first to sixth embodiment for generating an AAS preamble sequence.

First Embodiment

The first embodiment of the present invention is an element of downlink preamble sequences of all segments within the same cell, having the same cell identifier (ID), hereinafter referred to as 'ID'. Each element is mapped to subcarriers one-to-one to generate a new sequence, and then elements of the new sequence are segmented to generate an AAS preamble sequence. A first embodiment of the present invention will be described with reference to FIG. 5.

5 is a diagram schematically illustrating a process of generating an AAS preamble sequence in an IEEE 802.16e communication system according to a first embodiment of the present invention.

Before describing FIG. 5, it is assumed that the segment structure is the same structure as a general sector structure, and the IEEE 802.16 communication system uses a total of 1702 subcarriers, and one cell has three segments in total. For example, it is assumed that the structure has a structure of a total of three segments, that is, segment 0, segment 1, and segment 2, and it is also assumed that the downlink preamble sequence has a length of 568 or 567. Here, the downlink preamble sequence is a preamble sequence transmitted and received through the preamble region as described with reference to FIGS. 2 and 3 of the prior art, that is, a transceiver (base station (BS) and a mobile subscriber station (MSS)). In the following description, a preamble sequence for synchronizing acquisition) is referred to as 'MSS'.

Referring to FIG. 5, the first embodiment of the present invention first combines downlink preamble sequences 500, 510, and 520 allocated to each of segments in the same cell, that is, each of three segments of segment 0 to segment 2. We propose a method for generating the AAS preamble sequence. First, the downlink preamble sequences 500, 510, and 520 allocated to each of the three segments of the segment 0 to the segment 2 will be described below.

First, each of the elements of the downlink preamble sequence 500 allocated to segment 0 is a subcarrier having a value of 0 as a result of calculating a corresponding subcarrier index among the total of 1702 subcarriers by% 3. Only one-to-one mapping is assigned. That is, only the subcarrier 0, the subcarrier 3, the subcarrier 6, the subcarrier 9, ..., the subcarrier 1695, the subcarrier 1698, and the subcarrier 1701 have the downlink preamble sequence 500 of the segment 0. Each of the 568 elements of) is allocated. As a result, the sub-carrier set # 0 for the segment 0 is a set of subcarriers having a result of calculating the subcarrier index by% 3.

Secondly, each of elements of the downlink preamble sequence 510 allocated to segment 1 may be mapped one-to-one only to subcarriers having a result of calculating a corresponding subcarrier index of a total of 1702 subcarriers by% 3. Is assigned. That is, 567 elements of the downlink preamble sequence 510 of the segment 1 in subcarrier 1, subcarrier 4, subcarrier 7, subcarrier 10, ..., subcarrier 1696, and subcarrier 1699 only. Each of these is assigned. As a result, the subcarrier set # 1 for segment 1 is a set of subcarriers having a result of calculating the subcarrier index by% 3.

Third, each of the elements of the downlink preamble sequence 520 allocated to the segment 2 is mapped one-to-one only to subcarriers having a result of calculating a corresponding subcarrier index of a total of 1702 subcarriers by% 3. Is assigned. That is, 567 elements of the downlink preamble sequence 520 of the segment 2 in subcarrier 2, subcarrier 5, subcarrier 8, subcarrier 11, ..., subcarrier 1697, and subcarrier 1700 only. Each of these is assigned. As a result, the subcarrier set # 2 for the segment 2 is a set of subcarriers having a result of calculating the subcarrier index by% 3.

Elements of a downlink preamble sequence 500 assigned to segment 0, elements of a downlink preamble sequence 510 assigned to segment 1, and a downlink preamble sequence 520 assigned to segment 2 Each of the elements is combined to be mapped to the result of calculating the subcarrier index by% 3 to be mapped one-to-one to the 1702 subcarriers, thereby generating a new sequence 530. The new sequence 530 is segmented into a length set to the length of the AAS preamble sequence to generate the AAS preamble sequence.

In this case, what part of the new sequence 530 is segmented into the AAS preamble sequence may be different according to a method determined by the IEEE 802.16e communication system. As in the first embodiment of the present invention, each element of the downlink preamble sequences of segments having the same cell ID is mapped to subcarriers one-to-one to generate a new sequence, and then elements of the corresponding length in the new sequence. If the AAS preamble sequence is generated, each element of the AAS preamble sequence is mapped one-to-one to all subcarriers of the AAS preamble region, thereby maximizing the probability of detecting the AAS preamble sequence on the receiver side.

However, in the first embodiment of the present invention, since the AAS preamble sequence is generated by combining elements of the downlink preamble sequences of all the segments having the same cell ID, the AAS preamble sequence distinguishes each of the segments. It becomes impossible. Accordingly, the first embodiment of the present invention proposes a method for dividing the segments, which will be described below.

First, in the IEEE 802.16e communication system, up to 16 beams are used for each segment in the same cell. Therefore, in order to distinguish each of the 16 beams, the AAS preamble sequence has a frequency-domain side. A cyclic shift in Equation generates a required number of AAS preambles.

However, in a general IEEE 802.16e communication system, a variable K for the cyclic shift is defined for each segment in the same cell to distinguish the 16 beams, and the variable K is any one of integer values from 0 to 15. It has an integer value. However, in the first embodiment of the present invention, since the variable K is not defined for each segment but only within the same cell, the variable K must have an integer value from 0 to 47. Therefore, in the first embodiment of the present invention, the number of bits representing the variable K is increased (4 bits-> 6 bits) so that the value of the variable K can be supported. Herein, the variable K is included in the DL-MAP Physical Modifier IE, and the DL-MAP Physical Modifier IE is included in the DL-MAP message.

Second Embodiment

The second embodiment of the present invention segments the downlink preamble sequence currently used in the IEEE 802.16 communication system as it is, generates an AAS preamble sequence, and boosts and generates the generated AAS preamble sequence.

As described with reference to FIGS. 4A to 4C of the prior art part, a downlink preamble sequence of a general IEEE 802.16 communication system has a subcarrier in which elements of the downlink preamble sequence are not mapped when all subcarriers are considered in consideration of a segment structure. Will exist. However, the number of subcarriers occupied in the AAS preamble region to which the AAS preamble sequence is transmitted is significantly smaller than that of the preamble region to which the downlink preamble sequence is transmitted. If each of the elements is mapped one-to-one, there is a problem that the detection probability of the AAS preamble sequence is significantly lowered.

Therefore, in the second embodiment of the present invention, the AAS preamble sequence generated by segmenting the downlink preamble sequence is boosted and transmitted to maximize the probability of detecting the AAS preamble sequence on the receiving side. In the second embodiment of the present invention, since the downlink preamble sequence is generated as it is segmented, segmentation is possible. The boosting method may be applied in a manner as shown in Equation 1 below.

In Equation 1, C_AAS (k) represents the k-th element value of the AAS preamble sequence, and C_AAS_Boosting (k) is a method in which C_AAS (k) is preset, for example, a BPSK (Binary Phase Shift Keying) method. It represents the value after boosting. In Equation 1, Is a value that is multiplied to increase the transmission power of the AAS preamble sequence by three times. Where The reason for multiplying is that when the downlink preamble sequence is used as the AAS preamble sequence by adjusting the length as it is, as described in FIGS. 4A to 4C of the prior art, two-thirds of the subcarriers of the entire AAS preamble region are used. This is because the elements of the AAS preamble sequence are not mapped to carriers at all.

Third Embodiment

The third embodiment of the present invention generates an AAS preamble sequence as a completely new sequence without using the downlink preamble sequence currently used in the IEEE 802.16 communication system, and boosts and generates the generated AAS preamble sequence.

In general, the downlink preamble sequence has a structure that is repeated in the time-domain for time synchronization acquisition. The structure that is repeated in the time domain is generated by mapping each element of the downlink preamble sequence to subcarriers one by one in the frequency domain, spaced apart by a predetermined number of subcarriers. For example, a time-domain downlink preamble sequence having a structure that is repeated twice may include elements of the downlink preamble sequence of the frequency domain only on even or odd subcarriers in the frequency domain. Is mapped.

However, as described above, when there are subcarriers in which no value is transmitted in the frequency domain, the detection probability may be reduced in the case of the AAS preamble sequence.

Accordingly, in the third embodiment of the present invention, AAS preamble sequences mapped to even-numbered subcarriers and AAS preamble sequences mapped to odd-numbered subcarriers are generated as new sequences. Then, for example, after converting a value of each element of the AAS preamble sequence mapped to the even subcarriers into a complement value, each of the elements converted to the complementary value and the odd subcarriers An AAS preamble sequence may be generated by mapping elements of the AAS preamble sequence mapped to to one-to-one mapping to subcarriers of the AAS preamble region. In addition, the AAS preamble sequence detection probability may be maximized by boosting and transmitting the sequence of the AAS preamble mapped to the even-numbered subcarriers and the AAS preamble sequence mapped to the odd-numbered subcarriers. Here, the boosting is described in Equation 1 of You can change it to apply.

Fourth Embodiment

The fourth embodiment of the present invention converts the values of each of the elements of the downlink preamble sequence allocated to segment 0 of the preamble sequences of the segments in the same cell into complementary values as in the first embodiment of the present invention. Then, each of the elements of the downlink preamble sequence converted to the complementary value and the values of the elements of each of the downlink preamble sequences assigned to each of segment 1 and segment 2 are mapped one-to-one to subcarriers. After generating C, the elements of the new sequence are segmented to generate an AAS preamble sequence. A fourth embodiment of the present invention will be described with reference to FIGS. 6 and 7.

6 is a diagram schematically illustrating a process of generating an AAS preamble sequence in an IEEE 802.16e communication system according to a fourth embodiment of the present invention. In particular, values of elements of the downlink preamble sequence corresponding to segment 0 are complementary. A diagram schematically illustrating a process of generating an AAS preamble sequence corresponding to segment 0 by converting the value into a value.

Before describing FIG. 6, the IEEE 802.16 communication system uses a total of 1702 subcarriers, and one cell includes three segments in total, that is, segment 0 and three segments of segment 1 and segment 2. It is assumed that the structure has a downlink preamble sequence. Also, it is assumed that the downlink preamble sequence has a length of 568 or 567.

Referring to FIG. 6, first, in a fourth embodiment of the present invention, a new sequence 610 in which values of elements of a downlink preamble sequence allocated to segment 0 among segments in the same cell are converted into complementary values; A method of generating the AAS preamble sequence by simply combining downlink preamble sequences 620 and 630 allocated to each of segments of segment 1 and segment 2 is proposed. First, the new sequence 610 and the downlink preamble sequences 620 and 630 will be described.

First, each element of the new sequence 610 is allocated one-to-one mapping to only subcarriers having a result of calculating a corresponding subcarrier index by% 3 of the total 1702 subcarriers by 0. That is, 568 elements of the new sequence 610 only in subcarrier 0, subcarrier 3, subcarrier 6, subcarrier 9, ..., subcarrier 1695, subcarrier 1698, and subcarrier 1701. Each of these is assigned. As a result, the subcarrier set # 0 for segment 0 is a set of subcarriers having a result of calculating the subcarrier index by% 3.

Secondly, each of elements of the downlink preamble sequence 620 allocated to segment 1 may be mapped one-to-one only to subcarriers having a result of calculating a corresponding subcarrier index of a total of 1702 subcarriers by% 3. Is assigned. That is, 567 elements of the downlink preamble sequence 620 of the segment 1 on only subcarrier 1, subcarrier 4, subcarrier 7, subcarrier 10, ..., subcarrier 1696, and subcarrier 1699. Each of these is assigned. As a result, the subcarrier set # 1 for segment 1 is a set of subcarriers having a result of calculating the subcarrier index by% 3.

Third, each of the elements of the downlink preamble sequence 630 allocated to the segment 2 is mapped one-to-one only to subcarriers having a result of calculating a corresponding subcarrier index of a total of 1702 subcarriers by% 3. Is assigned. That is, 567 elements of the downlink preamble sequence 630 of the segment 2 on the subcarrier 2, the subcarrier 5, the subcarrier 8, the subcarrier 11, ..., the subcarrier 1697, and the subcarrier 1700 only. Each of these is assigned. As a result, the subcarrier set # 2 for the segment 2 is a set of subcarriers having a result of calculating the subcarrier index by% 3.

Each of the elements of the new sequence 610, the elements of the downlink preamble sequence 620 assigned to segment 1, and the elements of the downlink preamble sequence 630 assigned to segment 2, the subcarrier. Another new sequence 640 is generated by combining the indices to be mapped to the result of the% 3 operation to map one-to-one to the 1702 subcarriers. The new sequence 640 is segmented into a length set to the length of the AAS preamble sequence to generate the AAS preamble sequence. In this case, what part of the new sequence 640 is segmented into the AAS preamble sequence may be different according to a method determined by the IEEE 802.16e communication system. In FIG. 6, it is assumed that the AAS preamble sequence is generated by converting values of elements of the downlink preamble sequence corresponding to segment 0 to complementary values, but downlink preamble corresponding to segment 1 and segment 2. Of course, the AAS preamble sequence may be generated by converting values of elements of a sequence into complementary values.

FIG. 7 is a diagram schematically illustrating a process of generating an AAS preamble sequence in an IEEE 802.16e communication system according to a fourth embodiment of the present invention. In particular, each of downlink preamble sequences corresponding to segment 1 and segment 2 is respectively illustrated. A diagram schematically illustrating a process of generating an AAS preamble sequence corresponding to segment 0 by converting values of each element into complementary values.

Before describing FIG. 7, the IEEE 802.16 communication system uses 1702 subcarriers in total, and one cell has three segments in total, that is, segment 0, segment 1 and It is assumed that the structure has a total of three segments of segment 2, and it is also assumed that the downlink preamble sequence has a length of 568 or 567. In FIG. 7, the AAS preamble sequence corresponding to segment 0 is generated by converting values of elements of the downlink preamble sequences corresponding to segment 1 and segment 2 into complementary values. Since the operation is similar to that of generating the AAS preamble sequence corresponding to segment 0, the operation is almost similar to that of detailed description thereof.

Fifth Embodiment

The fifth embodiment of the present invention generates an AAS preamble sequence by mapping each of the elements of the downlink preamble sequences corresponding to all segments in the same cell to subcarriers one-to-one as in the first embodiment of the present invention. Rather than using the downlink preamble sequences, the AAS preamble sequence is generated. That is, the fifth embodiment of the present invention generates new sequences by assigning new element values to subcarriers except subcarriers to which elements of downlink preamble sequences corresponding to each of the segments are mapped. That is, three new sequences corresponding to each of three segments in the same cell are generated. Here, element values allocated to subcarriers except subcarriers to which elements of the downlink preamble sequences corresponding to each of the segments are mapped should be set to values such that the elements are not repeated with a specific pattern in the time domain. If the specific pattern is repeated, the detection probability of the AAS preamble sequence is reduced.

Therefore, in order to avoid the case where the specific pattern is repeated, the following equation (2) or (3) is applied.

In Equation 2 and Equation 3, C_AAS (k) represents the value of the k-th element on the ASS preamble sequence, Denotes an exclusive OR. That is, assuming that any downlink preamble sequence is '1XX0XX1XX1XX0XX0' (where X is a visual representation of no value being mapped in the frequency domain and no value is mapped to the subcarrier corresponding to X). The ASS preamble sequence is generated as '100011101100010' by Equation 2.

Sixth Embodiment

A sixth embodiment of the present invention generates downlink preamble sequences as the AAS preamble sequence by combining elements of the downlink preamble sequences corresponding to the AAS preamble sequence length without correlating to a subcarrier index. For example, assuming that any downlink preamble sequence is '1XX0XX1XX1XX0XX0', an AAS preamble sequence of '101100' is generated by combining elements of the arbitrary downlink preamble sequence regardless of the subcarrier index. In the sixth embodiment of the present invention, since the AAS preamble sequence is mapped to all subcarriers in the frequency domain, the probability of detecting the AAS preamble sequence on the receiver side is also maximized.

However, since the AAS preamble sequence may be transmitted not only through the AAS Diversity Map Zone region but also through the data burst region, a case in which an AAS preamble sequence having a required length cannot be generated using only elements of the existing downlink preamble sequence may occur. Therefore, the sixth embodiment of the present invention can be applied more efficiently in the IEEE 8021.16e communication system having a relatively long downlink preamble sequence.

Next, a structure of a transmitter, that is, a base station, of the IEEE 8021.16e communication system for performing a function in the embodiments of the present invention will be described with reference to FIG. 8.

8 is a block diagram illustrating a transmitter structure of an IEEE 8021.16e communication system for performing functions in embodiments of the present invention.

Referring to FIG. 8, the transmitter includes an AAS preamble sequence generator 811, a modulator 813, a multiplexer 815, and an encoder 817. ), A modulator 819, a serial to parallel converter 821, an Inverse Fast Fourier Transform (IFFT) device 823, Parallel to serial converter 825, guard interval inserter 827, digital to analog converter 829, and radio frequency (RF): Radio Frequency, hereinafter referred to as 'RF') processor 831.

First, the AAS preamble sequence generator 811 generates an AAS preamble sequence according to one of the first to sixth embodiments of the present invention and outputs the AAS preamble sequence to the modulator 813. The modulator 813 modulates the AAS preamble sequence output from the AAS preamble sequence generator 811 using a preset modulation scheme, for example, a BPSK scheme, and then outputs the modulated sequence to the multiplexer 815.

In addition, when information data to be transmitted is generated, the information data is input to the encoder 817. The encoder 817 codes the input information data with a preset encoding scheme and outputs the encoded information data to the modulator 819. The modulator 819 modulates the signal output from the encoder 817 using a preset modulation scheme and then outputs the modulated signal to the multiplexer 815. Here, the modulator 819 may use a quadrature phase shift keying (QPSK) method or a quadrature amplitude modulation (16QAM) method as the modulation method.

The multiplexer 815 receives a signal output from the modulator 813 and a signal output from the modulator 819 and outputs a signal output from the modulator 813 at that time, that is, an AAS preamble sequence or the modulator ( The signal output from 819, that is, the information data, is output to the serial / parallel converter 821. The serial / parallel converter 821 converts the signal output from the multiplexer 815 in parallel and outputs the same to the IFFT unit 823.

The IFFT unit 823 inputs the signal output from the serial / parallel converter 821 to perform IFFT and then outputs it to the parallel / serial converter 825. The parallel / serial converter 825 inputs the signal output from the IFFT unit 823, converts it in series, and outputs the converted signal to the guard interval inserter 827. The guard interval inserter 827 inputs the signal output from the parallel / serial converter 825 to insert a guard interval signal and outputs the guard interval signal to the digital / analog converter 829. Here, the guard interval is inserted to remove interference between the OFDMA symbol transmitted at the previous OFDMA symbol time and the current OFDMA symbol transmitted at the current OFDMA symbol time when transmitting the OFDMA symbol in the OFDMA communication system. . In addition, the guard interval is a "Cyclic Prefix" scheme in which the last constant samples of the OFDMA symbol in the time domain are copied and inserted into the effective OFDMA symbol, or the first constant samples of the OFDM symbol in the time domain are copied to the effective OFDMA. It is inserted in the "Cyclic Postfix" method which inserts into a symbol.

The digital-to-analog converter 829 inputs the signal output from the guard interval inserter 827, converts the analog signal, and outputs the analog signal to the RF processor 831. Here, the RF processor 831 includes components such as a filter and a front end unit, and transmits the signal output from the digital-to-analog converter 829 on actual air. After the RF process, the transmission is performed on the air through a Tx antenna.

In FIG. 8, a transmitter structure of an IEEE 8021.16e communication system for performing a function in embodiments of the present invention has been described. Next, a receiver structure corresponding to FIG. 8 will be described with reference to FIG. 9. .

9 is a block diagram illustrating a receiver structure corresponding to FIG. 8.

9, the receiver includes an RF processor 911, an analog / digital converter 913, a guard interval remover 915, and a serial / parallel converter. 917, Fast Fourier Transform (FFT) 919, de-multiplexer 921, and demodulators 923, 925. ) And a decoder 927.

First, a signal transmitted from a transmitter as described with reference to FIG. 8 is received through a receiver antenna of the receiver in a form of adding noise and experiencing a multipath channel. The signal received through the receive antenna is input to the RF processor 911, and the RF processor 911 down converts the signal received through the receive antenna to an intermediate frequency (IF) band. And then output to the analog-to-digital converter 913.

The analog / digital converter 913 digitally converts an analog signal output from the RF processor 911 and outputs the digital signal to the guard interval remover 915. The guard interval remover 915 removes the guard interval signal by inputting the signal output from the analog / digital converter 913 and outputs the signal to the serial / parallel converter 917. The serial / parallel converter 917 inputs a serial signal output from the guard interval eliminator 915 to perform parallel conversion and outputs the serial signal to the FFT unit 919.

The FFT unit 919 inputs the signal output from the serial / parallel converter 917, performs an FFT, and outputs the FFT to the demultiplexer 921. The demultiplexer 921 outputs a signal output from the FFT 919 to the demodulator 923 or to the demodulator 925 at that time. That is, the demultiplexer 921 outputs a signal output from the FFT 919 to the demodulator 923 when the transmitter transmits the AAS preamble sequence, and at the time when the transmitter transmits the information data. The signal output from the FFT 919 is output to the demodulator 925.

The demodulator 923 demodulates the signal output from the demultiplexer 921 into a demodulation scheme corresponding to the modulation scheme used by the transmitter, and restores the signal to the AAS preamble sequence. In addition, the demodulator 925 demodulates the signal output from the demultiplexer 921 into a demodulation scheme corresponding to the modulation scheme used by the transmitter and outputs the demodulation scheme to the decoder 927. The decoder 927 inputs a signal output from the demodulator 925, decodes the decoding signal by a decoding method corresponding to the encoding method used by the transmitter, and restores the information data.

In FIG. 9, a receiver structure corresponding to FIG. 8 has been described. Next, a process of generating an AAS preamble sequence according to embodiments of the present invention will be described with reference to FIG.

10 is a flowchart illustrating a preamble sequence generation process according to embodiments of the present invention.

Referring to FIG. 10, the AAS preamble sequence generator 811 as described in FIG. 9 first checks whether an AAS preamble sequence to be transmitted through the AAS Diversity Map Zone area is required in step 1011. If the test result requires the AAS preamble sequence to be transmitted through the AAS Diversity Map Zone area, the AAS preamble sequence generator 811 proceeds to step 1013. In step 1013, the AAS preamble sequence generator 811 divides the downlink preamble sequence into a size occupied by the AAS Diversity Map Zone in the frequency domain, that is, 2 OFDMA sub-channel size, that is, proceeds to step 1019. .

If the AAS preamble sequence to be transmitted through the AAS Diversity Map Zone area is not required in step 1011, the AAS preamble sequence generator 811 proceeds to step 1015. In step 1015, the AAS preamble sequence generator 811 checks whether the AAS preamble sequence to be transmitted through the data burst region is required. If the test result requires the AAS preamble sequence to be transmitted through the data burst region, the AAS preamble sequence generator 811 proceeds to step 1017. In step 1017, the AAS preamble sequence generator 811 divides the downlink preamble sequence by the size of an OFDMA subchannel in which a data burst to which the AAS preamble sequence is to be transmitted occupies in a frequency domain. In step 1019, the AAS preamble sequence generator 811 generates an AAS preamble sequence according to any one of the first to sixth embodiments of the present invention and ends.

In the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

The present invention as described above has the advantage of providing an AAS preamble sequence that maximizes the detection probability in an OFDMA communication system. In particular, the present invention has the advantage of using an downlink preamble sequence to provide an AAS preamble sequence that maximizes the detection probability while having a relatively low complexity.

1 is a view schematically showing a downlink frame structure when using the AAS method in a typical IEEE 802.16e communication system

2 is a diagram schematically illustrating a downlink frame structure when a FUSC / PUSC exchange scheme is used in a general IEEE 802.16 communication system and an AAS scheme is used.

3 schematically illustrates a downlink frame structure when an AMC switching scheme is used and a AAS scheme is used in a general IEEE 802.16 communication system.

4a schematically illustrates a downlink preamble sequence structure applied to segment 0 of a general IEEE 802.16 communication system;

4b schematically illustrates a downlink preamble sequence structure applied to segment 1 of a general IEEE 802.16 communication system;

4c schematically illustrates a downlink preamble sequence structure applied to segment 2 of a general IEEE 802.16 communication system;

5 is a diagram schematically illustrating a process of generating an AAS preamble sequence in an IEEE 802.16e communication system according to a first embodiment of the present invention.

FIG. 6 is a diagram schematically illustrating a process of generating an AAS preamble sequence in an IEEE 802.16e communication system according to a fourth embodiment of the present invention. In particular, values of elements of the downlink preamble sequence corresponding to segment 0 are complementary values. Is a diagram schematically illustrating a process of generating an AAS preamble sequence corresponding to segment 0 by converting to SLR

FIG. 7 is a diagram schematically illustrating a process of generating an AAS preamble sequence in an IEEE 802.16e communication system according to a fourth embodiment of the present invention. In particular, each element of each of the downlink preamble sequences corresponding to segment 1 and segment 2, respectively. Schematically illustrating a process of generating an AAS preamble sequence corresponding to segment 0 by converting values of? To complementary values

8 is a block diagram illustrating a transmitter structure of an IEEE 8021.16e communication system for performing a function in embodiments of the present invention.

9 is a block diagram illustrating a receiver structure corresponding to FIG. 8.

10 is a flowchart illustrating a preamble sequence generation process according to embodiments of the present invention.

Claims (22)

An adaptive antenna system (AAS) in an orthogonal frequency division multiple access communication system having a plurality of cells, each of the plurality of cells having A segments, and each of the cells having B subcarriers. In the method for generating a sequence, Generating, for each of the cells, A downlink preamble sequences previously allocated to each of the A segments to generate A AAS preamble sequences in a frequency domain; And generating inverse fast Fourier transforms of the A AAS preamble sequences in the frequency domain into A AAS preamble sequences in the time domain. The method of claim 1, The downlink preamble sequence is a preamble sequence used for synchronization acquisition of a transmission / reception period of the orthogonal frequency division multiple access communication system, and each element constituting the downlink preamble sequence is one-to-one mapping to B / A subcarriers. Said method characterized by the above-mentioned. The method of claim 2, The AAS preamble sequence is a preamble sequence used to use the AAS scheme, and the elements constituting the AAS preamble sequence are mapped one to one on C subcarriers smaller than the B / A. . The method of claim 3, Generating the AAS preamble sequence; Generating a first sequence by one-to-one mapping each of the elements of each of the A downlink preamble sequences allocated to the A segments in the same cell to corresponding ones of the B subcarriers; , Segmenting the C elements among the elements constituting the first sequence to generate the AAS sequence in the frequency domain. The method of claim 3, Generating the AAS preamble sequence; Segmenting C / A elements of each of the elements of the A downlink preamble sequences allocated to the A segments in the same cell to generate the AAS preamble sequences of the A frequency domain The method. The method of claim 5, And boosting each of the A AAS preamble sequences in the frequency domain by a preset transmission power to control the inverse fast Fourier transform. The method of claim 3, Generating the AAS preamble sequence; Generating a first sequence by converting values of each of elements of a downlink preamble sequence allocated to a specific one of the A segments in the same cell into complementary values; Each of the elements of the first sequence and the elements of the downlink preamble sequence allocated to the remaining segments except for the one specific segment are mapped one-to-one to corresponding subcarriers of the B subcarriers. Creating two sequences, And segmenting the C elements of the elements constituting the second sequence into an AAS sequence in the frequency domain. The method of claim 3, Generating the AAS preamble sequence; Generating A-1 sequences by converting values of elements of each of the elements of the downlink preamble sequences assigned to segments except one particular segment of the A segments in the same cell into complementary values; , Each of the elements of each of the A-1 sequences and each of the elements of the downlink preamble sequence allocated to the specific one segment are mapped to corresponding ones of the B subcarriers by one-to-one mapping. Creating a sequence, Segmenting the C elements among the elements constituting the first sequence to generate the AAS sequence in the frequency domain. The method of claim 3, Generating the AAS preamble sequence; For each of the A downlink preamble sequences assigned to the A segments in the same cell, each of the elements of the downlink preamble sequence is one-to-one to corresponding subcarriers of the B / A subcarriers. Mapping process, Generating a first sequence by one-to-one mapping of predetermined element values to each of the subcarriers except the B / A subcarriers in which each of the elements of the downlink preamble sequence among the B subcarriers is mapped one-to-one; and, Segmenting the C elements among the elements constituting the first sequence to generate the AAS sequence in the frequency domain. The method of claim 3, Generating the AAS preamble sequence; For each of the A downlink preamble sequences allocated to the A segments in the same cell, C elements of the elements of the downlink preamble sequence are segmented to generate an AAS sequence in the frequency domain. Said method. The method of claim 10, The downlink preamble sequence is a preamble sequence used for synchronous acquisition of a transmission / reception period of the orthogonal frequency division multiple access communication system, and each of the elements constituting a specific downlink preamble sequence of the A downlink preamble sequences. Is one-to-one mapped to B / A + one subcarriers, and each of the elements constituting each of the downlink preamble sequences except for the specific one downlink preamble sequence is mapped one-to-one to B / A subcarriers. Characterized in that the method. An adaptive antenna system (AAS) in an orthogonal frequency division multiple access communication system having a plurality of cells, each of the plurality of cells having A segments, and each of the cells having B subcarriers. An apparatus for generating a sequence, An AAS preamble sequence generator for generating A AAS preamble sequences in a frequency domain by combining A downlink preamble sequences previously allocated to each of the A segments for each of the cells; And an inverse fast Fourier transformer for inverse fast Fourier transforming the A AAS preamble sequences in the frequency domain into A AAS preamble sequences in the time domain. The method of claim 12, The downlink preamble sequence is a preamble sequence used for synchronization acquisition of a transmission / reception period of the orthogonal frequency division multiple access communication system, and each element constituting the downlink preamble sequence is one-to-one mapping to B / A subcarriers. Said device. The method of claim 13, The AAS preamble sequence is a preamble sequence used for using the AAS scheme, and the elements constituting the AAS preamble sequence are mapped one to one on C subcarriers smaller than the B / A. . The method of claim 14, The AAS preamble sequence generator; Generating a first sequence by one-to-one mapping each of the elements of each of the A downlink preamble sequences allocated to the A segments in the same cell to corresponding ones of the B subcarriers; The C element of the elements constituting the first sequence is segmented to generate the AAS sequence of the frequency domain. The method of claim 14, The AAS preamble sequence generator; Segment C / A elements of the elements of each of the A downlink preamble sequences allocated to the A segments in the same cell to generate AAS preamble sequences of the A frequency domain. The device. The method of claim 16, The apparatus; And a modulator configured to boost the inverse fast Fourier transform by boosting each of the A AAS preamble sequences in the frequency domain by a predetermined transmission power. The method of claim 14, The AAS preamble sequence generator; Generating a first sequence by converting values of elements of a downlink preamble sequence allocated to a specific one of the A segments in the same cell into complementary values, and generating a first sequence, and each of the elements of the first sequence And generating a second sequence by one-to-one mapping each of elements of the downlink preamble sequence allocated to the remaining segments except for the one specific segment to the corresponding subcarriers of the B subcarriers. Wherein the C elements of the two sequences are segmented to generate an AAS sequence in the frequency domain. The method of claim 14, The AAS preamble sequence generator; Generating A-1 sequences by converting the values of the elements of each of the elements of the downlink preamble sequences assigned to the segments except for a specific one of the A segments in the same cell into complementary values, and Each of the elements of each of the A-1 sequences and each of the elements of the downlink preamble sequence allocated to the specific one segment are mapped one-to-one to corresponding subcarriers of the B subcarriers and thus the first sequence. And generating C and segmenting the C elements of the elements constituting the first sequence into an AAS sequence of the frequency domain. The method of claim 14, The AAS preamble sequence generator; For each of the A downlink preamble sequences assigned to the A segments in the same cell, each of the elements of the downlink preamble sequence is one-to-one to corresponding subcarriers of the B / A subcarriers. The first sequence is mapped by one-to-one mapping of element values preset to each of the subcarriers except the B / A subcarriers to which each of the elements of the downlink preamble sequence of the B subcarriers are mapped one-to-one. After generating, the C element of the elements constituting the first sequence is segmented to generate the AAS sequence of the frequency domain. The method of claim 14, The AAS preamble sequence generator; For each of the A downlink preamble sequences allocated to the A segments in the same cell, C elements of the elements of the downlink preamble sequence are segmented to generate an AAS sequence in the frequency domain. The apparatus described above. The method of claim 21, The downlink preamble sequence is a preamble sequence used for synchronous acquisition of a transmission / reception period of the orthogonal frequency division multiple access communication system, and each of the elements constituting a specific downlink preamble sequence of the A downlink preamble sequences. Is one-to-one mapped to B / A + one subcarriers, and each of the elements constituting each of the downlink preamble sequences except for the specific one downlink preamble sequence is mapped one-to-one to B / A subcarriers. Characterized in that the method.