KR20060037101A - Apparatus and method for generating dl/ul map messages in broadband wireless system - Google Patents

Abstract

The present invention relates to a method for generating a MAP message in a broadband wireless communication system using a plurality of spatial channels, comprising: configuring a data burst allocation region in the same pattern for the plurality of spatial channels; Allocating at least one data burst for each of the plurality of spatial channels, generating a MAP information element (IE) including information of a plurality of data bursts allocated to the same region; And generating a MAP message including the generated plurality of MAP information elements. This invention has the advantage of significantly reducing the overhead (overhead) of the downlink / uplink MAP message.

AAS, OFDMA, SDMA, MAP, DL-MAP_IE, UL-MAP_IE

Description

Apparatus and method for generating downlink / uplink map message in broadband wireless communication system {APPARATUS AND METHOD FOR GENERATING DL / UL MAP MESSAGES IN Broadband Wireless SYSTEM}             

1 illustrates a cellular system that supports a conventional Space Division Multiple Access (SDMA) scheme.

2 illustrates a downlink and uplink frame structure of an 802.16 OFDMA system.

3 is a diagram illustrating a downlink frame structure in an OFDMA communication system supporting a space division multiple access scheme according to the prior art.

4 is a diagram illustrating the structure of a downlink MAP message and an uplink MAP message in a conventional OFDMA communication system.

FIG. 5 is a diagram illustrating a structure of a downlink MAP message and an uplink MAP message when using a SDMA scheme in an OFDMA communication system according to the prior art. FIG.

6 is a diagram illustrating a configuration of DL-MAP_IE according to an embodiment of the present invention.

7 is a diagram illustrating a configuration of UL-MAP_IE according to an embodiment of the present invention.                 

8 is a diagram illustrating the structure of a downlink MAP message and an uplink MAP message when using a SDMA scheme in an OFDMA communication system according to an embodiment of the present invention.

9 is a diagram illustrating a configuration of a base station for transmitting a MAP message in an OFDM communication system using a space division multiple access (SDMA) scheme according to an embodiment of the present invention.

10 is a diagram illustrating a procedure for configuring downlink MAP_IE in a base station of an OFDM communication system according to an embodiment of the present invention.

11 is a diagram illustrating a procedure for configuring uplink leakage MAP_IE in an OFDM communication system according to an embodiment of the present invention.

12 is a graph illustrating an overhead ratio of a DL-MAP message according to the present invention with respect to a DL_MAP message according to the prior art.

The present invention relates to an apparatus and a method for generating an uplink / downlink MAP message in a broadband wireless communication system, and in particular, an Orthogonal Frequency Division Multiple Access (OFDMA) supporting a Space Division Multiple Access (SDMA) scheme. The present invention relates to an apparatus and a method for reducing overhead of an uplink / downlink MAP message in a communication system.

In general, in the 4th Generation communication system, which is the next generation communication system, active research is being conducted to provide users with services having various Quality of Service (QoS) having a transmission rate of about 100 Mbps. Currently, the 3rd Generation communication system generally supports a transmission rate of about 384 Kbps in the outdoor having a relatively poor channel environment, and a maximum transmission rate of about 2 Mbps in a room having a relatively good channel environment.

Meanwhile, wireless local area network (LAN) systems and wireless metropolitan area network (MAN) systems generally support transmission rates of 20 Mbps to 50 Mbps. Such a wireless MAN system is suitable for supporting high-speed communication services because of its wide coverage and high speed transmission, but does not consider the mobility of a subscriber station at all. Therefore, in the 4th generation communication system, research is being actively conducted in the form of ensuring mobility and QoS in a wireless LAN system and a wireless MAN system that guarantee a relatively high transmission speed.

The orthogonal frequency division multiple access (OFDM) scheme and the orthogonal frequency division multiple access (OFDMA) scheme are applied to the physical channel of the wireless MAN system. Electronics Engineers) 802.16 system. That is, the IEEE 802.16 system realizes high-speed data transmission by transmitting a physical channel signal using a plurality of subcarriers.

Meanwhile, in the IEEE 802.16 system, standards for supporting an adaptive antenna system (AAS) mode and a non-AAS mode are provided in one frame. There are two main reasons for applying the AAS mode to the system. The first is an increase in cell capacity, and the second is an increase in cell coverage.

The adaptive antenna system (AAS) is a system that continuously detects a cell coverage area using an array antenna and adaptively forms a beam pattern in a variable wireless channel environment. For example, if there is only one terminal and there is no interference, the adaptive antenna system adaptively responds to the movement of the terminal by generating an effective antenna pattern that follows the movement of the terminal. At this time, the antenna pattern becomes a pattern which always shows the best gain in the terminal direction. Such an adaptive antenna system may be used to implement a Space Division Multiple Access (SDMA) system. That is, if there are N terminals, N beams may be generated in each terminal direction.

FIG. 1 illustrates a cellular system supporting a conventional SDMA scheme.

As illustrated, the base station 101 forms a spatial channel 1 transmitted to the beam 102 and a spatial channel 2 transmitted to the beam 103. At this time, the first spatial channel and the second spatial channel uses the same frequency and time resources. As such, uplink channel information is required to form a plurality of beams using the same resource in downlink. Accordingly, the existing IEEE 802.16 OFDMA system adds a preamble symbol to downlink and uplink for measuring a channel state of a corresponding beam.

2 illustrates a downlink and uplink frame structure of an 802.16 OFDMA system.

As shown, it can be seen that the AAS preamble is transmitted in front of each downlink burst and the uplink burst. The base station estimates a channel through an uplink AAS preamble and forms a beam using the estimated channel information for downlink beamforming. In this case, since the spatial channels formed by the beams are spatially separated from each other as shown in FIG. 1, even if they share the same frequency and time resources, the interference is not large. Therefore, every spatial channel can utilize all the frequency and time resources allowed by the system.

3 illustrates a downlink frame structure in an OFDMA communication system supporting a space division multiple access scheme according to the prior art. It is assumed that two spatial channels are formed using two beams as shown in FIG. 1.

First, looking at the structure of the frame 301 for the first beam 102, it can be seen that the downlink burst # 1 ~ burst # 4 is assigned to the first spatial channel. Looking at the structure of the frame 302 for the second beam 103, it can be seen that the downlink burst # 5 ~ burst # 9 is assigned to the spatial channel 2. Here, each of the downlink bursts # 1 to # 9 uses different frequency-time resources as shown. Meanwhile, an area corresponding to a wide beam in each frame is a portion that is radiated across a cell (or sector), and includes a preamble, a frame control header (FCH), and a downlink MAP (DL). -MAP) and UL MAP (UL-MAP) information is transmitted. The UE knows the spatial channel information (AAS preamble information) and the uplink / downlink burst region allocated thereto through the downlink MAP and the uplink MAP information on the wide beam.

As described above, two-dimensional region information (information on the frequency and time domain occupied by the corresponding burst in the frame) for each of the downlink and uplink bursts allocated to each spatial channel must be included in the DL-MAP and UL-MAP. The area occupied by the DL-MAP and the UL-MAP becomes large. This phenomenon worsens as the number of beams (or spatial channels) increases. Therefore, there is a need for a method for reducing the size (or overhead) of DL-MAP and UL-MAP.

4 shows the structure of a downlink MAP message and an uplink MAP message in a conventional OFDMA communication system. In particular, FIG. 4 shows a DL-MAP_IE format and a UL-MAP_IE format defined in the current 802.16 standard (IEEE P802.16-REVd / D5). The DL (UL) -MAP_IE corresponds one-to-one to each downlink (uplink) data burst, and includes information on a modulation scheme, a coding rate, and a frequency-time domain occupied by the burst.

Hereinafter, the information included in the MAP message will be described with reference to FIG. 4. Downlink Interval Usage Code (4 bits) and Uplink Interval Usage Code (4 bits) represent information about the data burst, and the receiver can know the modulation scheme and coding rate of the burst. N_CID (8 bits) represents the number of CIDs (Connection IDs) allocated to the data burst, and CID (16 bits) represents connection information for the corresponding data burst. According to the CID, the corresponding data burst may be broadcast, multicast, or unicast.

OFDM Symbol Offset (8 bits) indicates the OFDMA symbol position where the data burst begins. Subchannel Offset (6 bits) indicates the index of the subchannel where the data burst begins. Boosting (3 bits) represents the amount of amplification (or attenuation) of the subcarrier's power. The number of OFDM symbols (7 bits) represents the number of OFDMA symbols allocated to a data burst. The number of subchannels (No. of subchannels, 6 bits) represents the number of subchannels allocated to the data burst. Repetition coding indicator (2 bits) indicates a repetition coding scheme used for a data burst.

Duration (10 bits) represents the length of the data burst in OFDMA slot units. The ranging method (2 bits) represents a ranging method used for the purpose of system initial access, synchronization tracking, and offset correction in the uplink. For example, 0b00 represents initial ranging using two symbols and 0b11 represents bandwidth demand and periodic ranging using three symbols.

FIG. 5 illustrates the structure of a downlink MAP message and an uplink MAP message when a SDMA method is used in an OFDMA communication system according to the prior art. Here, it is assumed that the downlink frame structure is the same as FIG.

As mentioned above, since the DL (UL) -MAP is transmitted in a wide beam, all terminals present in the cell (sector) can receive it. A portion transmitted in a narrow beam allows the terminal to distinguish the spatial channels by differently assigning the AAS preambles, and uses PHYMOD_DL (UL) _IE as shown for the preamble allocation according to the spatial channel.

First, referring to the DL-MAP 504, the AAS preamble for the spatial channel 1 is allocated through the PHYMOD_DL_IE (1), and for each of the downlink bursts # 1 to burst # 4 allocated to the spatial channel 1 below. Allocate DL-MAP_IE. Similarly, the AAS preamble for the second spatial channel is allocated through PHYMOD_DL_IE (2), and DL-MAP_IE for each of downlink bursts # 5 to burst # 9 allocated to the second spatial channel is allocated. The UL-MAP 503 is also configured in the same way. That is, since the area allocation information for each of all data bursts allocated to each spatial channel must be included, the size of the MAP message is very large. As the number of constituent antennas of the array antenna configured in the base station increases, the number of spatial channels that can be distinguished through beamforming also increases, resulting in too much overhead of the MAP message. Therefore, when using the SDMA scheme, there is a need for a scheme for configuring a downlink / uplink MAP message more efficiently.

Accordingly, an object of the present invention is to provide an apparatus and method for efficiently constructing a downlink / uplink MAP message when using a SDNA scheme in a broadband wireless communication system.

Another object of the present invention is to provide an apparatus and method for reducing overhead of downlink / uplink MAP message when using a SDMA scheme in a broadband wireless communication system.

According to a first aspect of the present invention for achieving the above objects, a method for generating a MAP message in a broadband wireless communication system using a plurality of spatial channels, the data burst for the plurality of spatial channels MAP information element (IE) including a process of configuring an allocation area in the same pattern, allocating at least one data burst for each of the plurality of spatial channels, and information on a plurality of data bursts allocated to the same area. And generating a MAP message including the generated plurality of MAP information elements.

According to a second aspect of the present invention, an apparatus for transmitting a MAP message in a broadband wireless communication system using a plurality of spatial channels, the data burst allocation area for the plurality of spatial channels in the same pattern A scheduler configured to generate a MAP information element (IE) including information of a plurality of data bursts allocated to the same region, and to create and output a MAP message including the generated plurality of MAP information elements. And a transmission modem for processing and outputting a MAP message from the scheduler according to a predetermined transmission standard, a duplexer for transmitting a signal from the transmission modem to an array antenna, and a signal from the duplexer for a predetermined beam pattern. The error of radiating the entire cell is characterized by including an antenna.

According to a third aspect of the present invention, a method for transmitting a MAP message in a broadband wireless communication system using a plurality of spatial channels, the data burst allocation area in the same pattern for the plurality of spatial channels Configuring, allocating at least one data burst for each of the plurality of spatial channels, and at least one MAP information element (IE) including information of a plurality of data bursts allocated to the same region. Generating as many data burst allocation regions as are allocated to a spatial channel, creating a MAP message including the generated MAP information elements, and processing the created MAP message according to a predetermined transmission standard; And radiating the processed MAP message through the array antenna to the entire cell in a wide beam. The key is characterized by including the process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, a method for reducing overhead of downlink / uplink MAP message in case of using Space Division Multiple Access (SDMA) in an OFDMA communication system will be described. To this end, the present invention configures a data burst allocation area for a plurality of spatial channels in the same manner. In this case, the MCS (Modulation and Coding Scheme) level of the allocated data burst can be adaptively responded to the channel state by allocating using DIUC (UIUC in the case of uplink). That is, assuming a system having N _burst data bursts in each spatial channel and an array antenna capable of generating N _beam spatial channels, the conventional scheme requires N _burst * N _beam MAP_IEs. The present invention requires N _burst MAP_IEs.

Next, a detailed MAP_IE configuration method will be described.

6 shows a configuration of a DL-MAP_IE according to an embodiment of the present invention. Since the present invention unifies a data burst allocation region for a plurality of spatial channels, one MAP_IE includes information about a plurality of data bursts allocated to the same region in a plurality of spatial channels.

As shown, in the case of the SDMA mode, a downlink interval usage code (DIUC), a connection ID (N_CID), a plurality of CIDs, an OFDM symbol offset (OFDM symbol offset), and a sub-mode are used. Create DL-MAP_IE including Sun offset, Boosting, Number of OFDM symbols (No.OFDM symbols), Number of subchannels (No.Subchannels), and Repetition Coding Indicator do.

In the SDMA mode according to the present invention, a presence bit, a downlink interval usage code (DIUC), a connection ID (N_CID), a plurality of CIDs, an OFDM symbol offset, a subchannel offset A DL-MAP_IE including a boosting, a number of OFDM symbols (No. OFDM symbols), a number of subchannels (no. Subchannels), and a repetition coding indicator (repetition coding indicator) is prepared. Here, {present bit, DIUC, N_CID, a plurality of CIDs} may be created as many as the maximum number of spatial channels Max_Num_Spatial_Ch.

As described above, the DL-MAP_IE according to the present invention distinguishes between using and not using SDMA according to the presence or absence of a presence bit. The case where the presence bit precedes the downlink interval usage code (DIUC) is a case of using SDMA. The presence bit indicates whether the predetermined number Max_Num_Spatial_Ch is utilized for each of the spatial channels. When the presence bit is assigned to '1', the utilization of the corresponding spatial channel is indicated, and then a downlink interval usage code (DIUC) for the corresponding data burst of the spatial channel is allocated. Through the DIUC allocation, a modulation scheme and a coding rate of a corresponding data burst can be set. On the other hand, since the data burst allocation region is unified for a plurality of spatial channels, resource allocation information (OFDMA Symbol offset, Subchannel offset, No. OFDMA Symbols, No. Subchannels, etc.) in the frequency-time domain is only once in DL-MAP_IE. Set it. In this way, since the allocation information for a plurality of data bursts using the same resource for one DL-MAP_IE can be loaded, the overhead of the DL-MAP message can be significantly reduced. In particular, the number of resource allocation information (OFDMA Symbol offset, Subchannel offset, No. OFDMA Symbols, No. Subchannels, etc.) created in the DL-MAP message can be significantly reduced.

7 illustrates a configuration of UL-MAP_IE according to an embodiment of the present invention.

Like the above-described DL-MAP_IE, the case of using SDMA according to the presence or absence of presence bits is distinguished from the case of not using the SDMA. The presence bit precedes the CID (Connection ID) when SDMA is used. The presence bit indicates whether the predetermined number Max_Num_Spatial_Ch is utilized for each of the spatial channels. Accordingly, {presence bit, CID, duration, repetition coding indicator} may be created as many as the maximum number of spatial channels.

When the presence bit is assigned with '1', the utilization of the corresponding spatial channel is indicated, and then an Uplink Interval Usage Code (UIUC) for the corresponding data burst of the spatial channel is allocated. Through the UIUC allocation, a modulation scheme and a coding rate of a corresponding data burst can be set. As such, since allocation information for a plurality of data bursts using the same resource may be loaded for one UL-MAP_IE, the overhead of the UL-MAP message may be significantly reduced.

FIG. 8 illustrates structures of a downlink MAP message and an uplink MAP message when using a SDMA scheme in an OFDMA communication system according to an embodiment of the present invention. In the drawing, only the downlink frame structure is shown as an example.

As shown in the drawing, when two spatial channels are used, the data burst allocation region for the frame of the spatial channel 1 and the data burst allocation region (time-frequency region) for the frame of the spatial channel 2 are in the same pattern. You can see that it is configured. Specifically, the allocation areas (frequency and time domains) of burst # 1 and burst # 5 are the same, burst # 2 and burst # 6 are the same, burst # 3 and burst # 7 are the same, burst # 4 and burst # 8 is the same.

Referring to FIG. 8, since a DL (UL) -MAP is transmitted in a wide beam, all terminals existing in a cell (sector) can receive it. A portion transmitted in a narrow beam allows the UE to distinguish spatial channels by differently assigning the AAS preambles as described in FIG. 5, and uses the existing PHYMOD_DL (UL) _IE for preamble allocation according to the spatial channel. Extend it. According to the prior art, as described in FIG. 5, one AAS preamble is allocated to one PHYMOD_DL (UL) _IE, but the present invention allocates all preambles to be used for each spatial channel. Therefore, the size of the PHYMOD_DL (UL) _IE is increased by the number of times of the spatial channels. However, since the number of AAS preambles allocated to the MAP message is the same as before, the overhead is the same as the conventional method.

First, referring to the DL-MAP 804, all of the AAS preambles for the first and second spatial channels are allocated through the PHYMOD_DL_IE (1,2). Thereafter, DL-MAP_IE is allocated to each of downlink burst sets {1,5}, {2,6}, {3,7}, and {4,8}. For example, DL-MAP_IE (1,5) includes information on DL burst # 1 and DL burst # 5 allocated to the same frequency-time domain in each spatial channel. Here, the DL burst # 1 and the DL burst # 5 occupy the same area in each frame, but may have different levels of modulation and coding scheme (MCS).

Meanwhile, the UL-MAP 803 is also configured in the same manner. In this embodiment, it is assumed that five bursts are allocated to each spatial channel UL frame. All AAS preambles are allocated to spatial channels 1 and 2 through PHYMOD_UL_IE (1, 2). Thereafter, UL-MAP_IE is allocated to each of downlink burst sets {1,5}, {2,6}, {3,7}, and {4,8}. For example, UL-MAP_IE (1,6) includes information about data UL burst # 1 and UL burst # 6 allocated to the same frequency-time domain in each spatial channel. Here, the UL burst # 1 and the UL burst # 6 occupy the same area in each frame, but may have different levels of modulation and coding scheme (MCS).

9 illustrates a configuration of a base station for transmitting a MAP message in an OFDM communication system using a SDMA scheme according to an embodiment of the present invention.                     

As shown, the base station according to the present invention includes a scheduler 901, a MAC block 903 connected to a higher layer, a transmission modem 905, a reception modem 905, a duplexer 907, and a plurality of base stations. And an antenna array 911 for forming a beam (spatial channel).

Referring to FIG. 9, first, the MAC block 903 performs a process of appropriately processing transmission data received from an upper layer according to a connection method with the transmission modem 905 and delivers the transmission data to the transmission modem 905. . The MAC block 903 processes the received data received from the reception modem 907 according to a connection method with a higher layer and transfers the received data to the upper layer.

The transmission modem 905 includes a channel code block, a modulation block, an RF transmission block, and the like. The transmission modem 905 converts data from the MAC block 903 into a form suitable for radio section transmission and transfers the data to the duplexer 909. . The channel code block includes a channel encoder, an interleaver, a modulator, and the like, and the modulation block is an IFFT (Inverse Fast Fourier Transform) for loading transmission data on a plurality of orthogonal subcarriers. The RF transmission block may include a filter and an RF front end unit.

On the other hand, the reception modem 907 is configured to include an RF reception block, a demodulation block, a channel decoding block, etc., and recovers data from the radio section signal from the duplexer 909 and transfers the data to the MAC block 903. . Here, the RF reception block includes a filter, an RF front end unit, and the like, and the demodulation block includes a fast fourier transform (FFT) operator corresponding to the inverse fast fourier transform (IFFT) operator. The channel decoding block may include a demodulator, a deinterleaver, a channel decoder, and the like.

The duplexer 909 transmits a reception signal (downlink signal) from the array antenna 911 to the reception modem 907 in a TDD manner, and transmits a transmission signal (uplink signal) from the transmission modem 905. Transfer to the array antenna (911).

The scheduler 901 is responsible for planning and indicating data transmission of uplink and downlink in consideration of cell loading, channel status of individual terminals, and the like. For example, in the IEEE 802.16 communication system, the scheduler 901 prepares UL / DL MAP information, which is configuration information of an uplink / downlink frame, and delivers it to the MAC block 903, and the MAC block 903 is the scheduler. The downlink frame is transmitted and the uplink frame is received based on the UL / DL MAP information from 901.

An operation for transmitting a MAP message based on the configuration of FIG. 9 will now be described.

First, as described above, the scheduler 901 prepares UL-MAP information, which is configuration information of an uplink frame, and DL-MAP information, which is configuration information of a downlink frame, and transmits the information to the MAC block 903. Herein, DL (UL) -MAP information includes one information element (IE) including information of AAS preambles allocated to a plurality of spatial channels as shown in FIG. 8 and a plurality of information using the same resource. It comprises a plurality of information elements including information in the data bursts.

The MAC block 903 creates a physical channel message with the DL / UL MAP information from the scheduler 901 and delivers the physical channel message to the transmission modem 905. Then, the transmission modem 905 converts the message from the MAC block 903 into a form that can be actually transmitted through channel code, baseband modulation, and RF modulation, and delivers the message to the duplexer 909. The duplexer 909 radiates the signal from the transmission modem 905 to the entire area of the cell (or sector) through the array antenna 911.

10 illustrates a procedure for configuring downlink MAP_IE in a base station of an OFDM communication system according to an embodiment of the present invention. The following algorithm is for explaining a procedure of configuring MAP_IE for a plurality of DL data bursts allocated to the same region of a plurality of spatial channels.

Referring to FIG. 10, the scheduler 901 of the base station first checks whether the current system operates in space division multiple access (SDMA) in step 1001. In operation SDMA, the scheduler 901 checks whether the variable m indicating the number of spatial channels is greater than the number of spatial channels Max_Num_Spatial_Ch in step 1003. The initial value of the variable m is '1'. If the variable m is greater than the number of spatial channels, the scheduler 901 proceeds to step 1029.

If the variable m is less than or equal to the number of the spatial channels, the scheduler 901 proceeds to step 1005 to set presence bits in the DL-MAP_IE. In this case, when the specific data burst is used in the m frame channel frame, the existence bit is set to '1', and if the corresponding data burst is not used, the existence bit is set to '0'.

In operation 1007, the scheduler 901 checks whether the set existence bit is '1'. That is, it is checked whether the specific data burst is used in the m frame channel frame. If the particular data burst is not used, the scheduler 901 proceeds to step 1018 to increase the variable m by '1' and then returns to step 1003 to perform the following steps again. If the specific data burst is used, the scheduler 901 proceeds to step 1009 to set a downlink interval usage code (DIUC) in the DL-MAP_IE. As described above, the DIUC is information for designating a modulation scheme and a coding rate for a corresponding data burst.

After setting the DIUC, the scheduler 901 proceeds to step 1011 and checks whether the value set in the DIUC is 15 (= 1111). If the DIUC value is '15', the scheduler 901 proceeds to step 1013, sets an extended DIUC dependent IE (DIUC) in the DL-MAP_IE, and then proceeds to step 1018. Here, since the extended DIUC is variable in length, unlike the DIUC fixed to 4 bits, more information can be set for the corresponding data burst.

If the DIUC value is not '15', the scheduler 901 checks whether the INC_CID value set in the CID_SWITCH_IE is '1' in step 1015. If the INC_CID value is not '1', the scheduler 901 proceeds to step 1018 and increases the variable m by '1' and returns to step 1003. If the INC_CID value is '1', the scheduler 901 proceeds to step 1017 to set the number of connection identifiers (N_CID) allocated to the DL-MAP_IE, and as many as the IDs (CIDs) of the N_CID. Are set in the DL-MAP_IE, and then the process proceeds to step 1018.

On the other hand, if the system does not operate in SDMA, the scheduler 901 proceeds to step 1019 to set a Downlink Interval Usage Code (DIUC) in the DL-MAP_IE. As described above, the DIUC is information for designating a modulation scheme and a coding rate for a corresponding data burst. In operation 1021, the scheduler 901 checks whether the value set in the DIUC is 15 (= 1111). If the DIUC value is '15', the scheduler 901 proceeds to step 1023, sets an extended DIUC (DIUC) in the DL-MAP_IE, and ends the present algorithm. Here, since the extended DIUC is variable in length, unlike the DIUC fixed to 4 bits, more information can be set for the corresponding data burst.

If the DIUC value is not '15', the scheduler 901 checks whether the INC_CID value set in the CID_SWITCH_IE is '1' in step 1025. If the INC_CID value is not '1', the scheduler 901 proceeds to step 1029. If the INC_CID value is '1', the scheduler 901 proceeds to step 1027 to set the number of connection identifiers (N_CIDs) allocated to the DL-MAP_IE, and sets the connection identifiers (CIDs) corresponding to the N_CIDs. After setting in the DL-MAP_IE, the process proceeds to step 1029.

Finally, in step 1029, the scheduler 901 performs OFDM symbol offset, subchannel offset, boosting, number of OFDM symbols (No. OFDMA Symbols), and number of subchannels. (No. Subchannels) and Repetition Coding Indicator are set in the DL-MAP_IE, and then the algorithm is terminated.

As described above, when operating in SDMA, presence bits and DIUCs are described as many as the number of spatial channels, and Extended DIUC dependent IE (DIUC) or N_CID and CID are described according to the value of the DIUC. The DL-MAP_IE for SDMA is formed by describing resource allocation information (OFDMA Symbol offset, Subchannel offset, No. OFDMA Symbols, etc.) of data burst, which is information shared regardless of the spatial channel.

11 illustrates a procedure for configuring uplink leakage MAP_IE in an OFDM communication system according to an embodiment of the present invention. The following algorithm is for explaining a procedure of configuring MAP_IE for a plurality of UL data bursts allocated to the same region of a plurality of spatial channels.

Referring to FIG. 11, the scheduler 901 of the base station first checks whether the current system operates in space division multiple access (SDMA) in step 1101. In operation SDMA, the scheduler 901 checks whether the variable m representing the number of spatial channels is greater than the number of spatial channels Max_Num_Spatial_Ch in step 1103. The initial value of the variable m is '1'. If the variable m is greater than the number of spatial channels, the scheduler 901 ends the present algorithm.

If the variable m is less than or equal to the number of the spatial channels, the scheduler 901 sets a presence bit in the UL-MAP_IE in step 1105. In this case, when the specific data burst is used in the m frame channel frame, the existence bit is set to '1', and when the specific data burst is not used, the existence bit is set to '0'.

In operation 1107, the scheduler 901 checks whether the set existence bit is '1'. That is, it is checked whether the specific data burst is used in the m frame channel frame. If the specific data burst is not used, the scheduler 901 proceeds to step 1116, increases the variable m by '1', and returns to step 1103 to perform the following steps again. If the specific data burst is used, the scheduler 901 sets a link identifier (CID) and an uplink interval usage code (UIUC) in the UL-MAP_IE in step 1109. As described above, the UIUC is information for designating a modulation scheme and a coding rate for a corresponding data burst.

After setting the UIUC, the scheduler 901 proceeds to step 1111 and checks whether the value set in the UIUC is 15 (= 1111). If the UIUC value is '15', the scheduler 901 proceeds to step 1113, sets an extended UIUC dependent IE (UIUC) in the UL-MAP_IE, and then proceeds to step 1116. Here, since the extended UIUC has a variable length, unlike the UIUC field fixed to 4 bits, more information can be set for the corresponding data burst.

If the UIUC value is not '15', the scheduler 901 proceeds to step 1115, sets a duration and a repetition coding indicator to the UL-MAP_IE, and then proceeds to step 1116. do. The scheduler 901 increases the variable m by '1' in step 1116 and returns to step 1103 to perform the following steps again.

On the other hand, if the system does not operate in SDMA, the scheduler 901 proceeds to step 1117 to set the link identifier (CID) and the UIUC (Uplink Interval Usage Code) in the UL-MAP_IE. As described above, the UIUC is information for designating a modulation scheme and a coding rate for a corresponding data burst. In operation 1119, the scheduler 901 checks whether the value set in the UIUC is 12 (= 1100). If the UIUC value is '12', the scheduler 901 proceeds to step 1121 and the OFDM symbol offset, subchannel offset, boosting, and number of OFDM symbols (No). After the OFDMA symbols, the number of subchannels and the ranging method are set in the UL-MAP_IE, the algorithm is terminated.

If the UIUC value is not '12', the scheduler 901 proceeds to step 1123 and checks whether the UIUC value is 14 (= 1110). If the UIUC value is '14', the scheduler 901 proceeds to step 1125 and sets CDMA_Allocation_IE in the UL-MAP_IE and ends the present algorithm.

If the UIUC value is not '14', the scheduler 901 proceeds to step 1127 and checks whether the UIUC value is 15 (= 1111). If the UIUC value is '15', the scheduler 901 proceeds to step 1129 and sets the Extended UIUC dependent IE (UIUC) in the UL-MAP_IE and ends the present algorithm. Here, since the extended DIUC is variable in length, unlike the DIUC fixed to 4 bits, more information can be set for the corresponding data burst. If the DIUC value is not '15', the scheduler 901 proceeds to step 1131, sets a duration and a repetition coding indicator to the UL-MAP_IE and ends the present algorithm. .

12 is a graph illustrating an overhead ratio of a DL-MAP message according to the present invention with respect to a DL-MAP message according to the prior art. The DL-MAP message according to the prior art is written as shown in FIG. 4, and the DL-MAP message according to the present invention is written as shown in FIG. 6.

As shown, when the number of spatial channels is 1, that is, when SDMA is not applied, the same overhead as the existing DL-MAP is shown, but the overhead decreases as the number of spatial channels increases. It can be seen. For example, if there are 8 spatial channels and 10 data bursts per spatial channel, the DL-MAP overhead ratio is 43%. This means that the present invention can reduce the overhead by 57% compared to the prior art.

As described above, the present invention reduces the overhead of downlink / uplink MAP messages when using a Space Division Multiple Access (SDMA) scheme in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system. There is an advantage to reduce.

Claims (21)

A method for generating a MAP message in a broadband wireless communication system using a plurality of spatial channels, Configuring a data burst allocation area in the same pattern for the plurality of spatial channels; Allocating at least one data burst for each of the plurality of spatial channels; Generating a MAP information element (IE) including information of a plurality of data bursts allocated to the same region; And generating a MAP message including the generated plurality of MAP information elements. The method of claim 1, wherein the MAP information element, Codes for designating a Modulation and Coding Scheme (MCS) level for each of a plurality of data bursts assigned to the same region; The device comprises common resource allocation information for the plurality of data bursts. The method of claim 2, The code for designating the MCS level is a Downlink Interval Usage Code (DIUC). The method of claim 1, wherein the MAP information element, m is a presence bit indicating whether or not the corresponding data burst allocation area is used in spatial channel m when the variable increases from 1 to the number of spatial channels; A downlink interval usage code (DIUC) recorded when the existence bit is '1', Extended DIUC dependent IE (DIUC) recorded when the recorded DIUC value is a predetermined value, The number of connection identifiers N_CID and a plurality of connection identifiers that are recorded when the recorded DIUC value is not the predetermined value; And common resource allocation information for a plurality of data bursts assigned to the same frequency-time resource. The method of claim 2 or 4, wherein the resource allocation information, OFDM symbol offset for specifying the position of the OFDM symbol where the data burst starts, subchannel offset for specifying the index of the subchannel where the data burst starts, and amplification for the power of the subcarrier. Boosting for specifying the degree, No. OFDMA symbols for specifying the number of OFDM symbols allocated to the data burst, and subchannels for specifying the number of subchannels assigned to the data burst. Device comprising a number (No. Subchannels). The method of claim 1, wherein the MAP information element, m is a presence bit indicating whether or not the corresponding data burst allocation area is used in spatial channel m when the variable increases from 1 to the number of spatial channels; A link identifier (CID) and a UIUC (Uplink Interval Usage Code) recorded when the existence bit is '1', Extended UIUC dependent IE (UIUC) recorded when the recorded UIUC value is a predetermined value, And a repetition coding indication and a duration of a corresponding data burst to be recorded when the recorded UIUC value is not the predetermined value. The method of claim 1, The MAP message further comprises an information element (IE) in which information of AAS (Adaptive Antenna System) preambles allocated to each of the plurality of spatial channels is recorded. An apparatus for transmitting a MAP message in a broadband wireless communication system using a plurality of spatial channels, The data burst allocation region is configured in the same pattern for the plurality of spatial channels, and a MAP information element (IE) including information of a plurality of data bursts allocated to the same region is generated, and the generated plurality A scheduler for creating and outputting a MAP message including MAP information elements of A transmission modem for processing and outputting a MAP message from the scheduler according to a predetermined transmission standard; A duplexer for transmitting a signal from the transmission modem to an array antenna; And wherein the error of radiating a signal from the duplexer to the entire cell in a predetermined beam pattern comprises an antenna. The method of claim 8, wherein the MAP information element, Codes for designating a Modulation and Coding Scheme (MCS) level for each of a plurality of data bursts assigned to the same region; The device comprises common resource allocation information for the plurality of data bursts. The method of claim 9, The code for designating the MCS level is a Downlink Interval Usage Code (DIUC). The method of claim 8, wherein the MAP information element, m is a presence bit indicating whether or not the corresponding data burst allocation area is used in spatial channel m when the variable increases from 1 to the number of spatial channels; A downlink interval usage code (DIUC) recorded when the existence bit is '1', Extended DIUC dependent IE (DIUC) recorded when the recorded DIUC value is a predetermined value, A number of connection identifiers N_CID and a plurality of connection identifiers that are recorded when the recorded DIUC value is not the predetermined value; And common resource allocation information for a plurality of data bursts assigned to the same frequency-time resource. The method of claim 9 or 11, wherein the resource allocation information, OFDM symbol offset for specifying the position of the OFDM symbol where the data burst starts, subchannel offset for specifying the index of the subchannel where the data burst starts, and amplification for the power of the subcarrier. Boosting for specifying the degree, No. OFDMA symbols for specifying the number of OFDM symbols allocated to the data burst, and subchannels for specifying the number of subchannels assigned to the data burst. Device comprising a number (No. Subchannels). The method of claim 8, wherein the MAP information element, m is a presence bit indicating whether or not the corresponding data burst allocation area is used in spatial channel m when the variable increases from 1 to the number of spatial channels; A link identifier (CID) and a UIUC (Uplink Interval Usage Code) recorded when the existence bit is '1', Extended UIUC dependent IE (UIUC) recorded when the recorded UIUC value is a predetermined value, And a repetition coding indication and a duration of a corresponding data burst to be recorded when the recorded UIUC value is not the predetermined value. The method of claim 8, The MAP message further comprises an information element (IE) in which information of AAS (Adaptive Antenna System) preambles allocated to each of the plurality of spatial channels is recorded. A method for transmitting a MAP message in a broadband wireless communication system using a plurality of spatial channels, Configuring a data burst allocation region in the same pattern for the plurality of spatial channels, and allocating at least one data burst for each of the plurality of spatial channels; Generating a MAP information element (IE) including information of a plurality of data bursts allocated to the same area as the number of data burst allocation areas allocated to at least one spatial channel; Creating a MAP message including the generated plurality of MAP information elements; Processing the created MAP message according to a predetermined transmission standard; And radiating the processed MAP message to the cell as a wide beam through an array antenna. The method of claim 15, wherein the MAP information element, Codes for designating a Modulation and Coding Scheme (MCS) level for each of a plurality of data bursts assigned to the same region; And common resource allocation information for the plurality of data bursts. The method of claim 16, The code for designating the MCS level is a downlink interval usage code (DIUC). The method of claim 15, wherein the MAP information element, m is a presence bit indicating whether or not the corresponding data burst allocation area is used in spatial channel m when the variable increases from 1 to the number of spatial channels; A downlink interval usage code (DIUC) recorded when the existence bit is '1', Extended DIUC dependent IE (DIUC) recorded when the recorded DIUC value is a predetermined value, The number of connection identifiers N_CID and a plurality of connection identifiers that are recorded when the recorded DIUC value is not the predetermined value; And common resource allocation information for a plurality of data bursts assigned to the same frequency-time resource. The method of claim 16 or 18, wherein the resource allocation information, OFDM symbol offset for specifying the position of the OFDM symbol where the data burst starts, subchannel offset for specifying the index of the subchannel where the data burst starts, and amplification for the power of the subcarrier. Boosting for specifying the degree, No. OFDMA symbols for specifying the number of OFDM symbols allocated to the data burst, and subchannels for specifying the number of subchannels assigned to the data burst. Method comprising a number (No. Subchannels). The method of claim 15, wherein the MAP information element, m is a presence bit indicating whether or not the corresponding data burst allocation area is used in spatial channel m when the variable increases from 1 to the number of spatial channels; A link identifier (CID) and a UIUC (Uplink Interval Usage Code) recorded when the existence bit is '1', Extended UIUC dependent IE (UIUC) recorded when the recorded UIUC value is a predetermined value, And a repetition coding indication and a duration of a corresponding data burst to be recorded when the recorded UIUC value is not the predetermined value. The method of claim 15, The MAP message further comprises an information element in which information of adaptive antenna system (AAS) preambles allocated to each of the plurality of spatial channels is recorded.

Images