KR101084133B1 - Coding Type Application Method in Broadband Wireless Access System - Google Patents

Abstract

Receiving, by the mobile station, at least one burst profile comprising information about a coding type and information about adaptive modulation and coding (AMC) corresponding to the information about the coding type; The present invention relates to a coding type application method comprising performing type negotiation and performing data transmission / reception using a burst profile according to the negotiation result, and efficiently applying AMC even when a plurality of coding schemes are supported. It can work.

Coding Type, Burst Profile, Downlink Channel Descriptor, Uplink Channel Descriptor

Description

In a broadband wireless access system, a method for applying coding types {Method for Applying Coding Types in Broadband Wireless Access System}

1 is an exemplary explanatory diagram showing a threshold for changing a burst profile.

2 is a diagram illustrating an embodiment of a method of mapping AMC to DIUC for each coding scheme.

3 is a diagram illustrating another embodiment of a method of mapping AMC to DIUC for each coding scheme.

4 is a flowchart illustrating an exemplary method of applying a burst profile according to the present invention;

5 is another exemplary flowchart illustrating a burst profile application method according to the present invention;

The present invention relates to a coding type application method applied to a broadband wireless access system. More specifically, when two or more mobile stations support different coding types, coding for efficiently performing AMC corresponding to the coding type. It is about how to apply type.

In a broadband wireless access system, when Orthogonal Frequency Division Multiple Access (OFDMA) is used, the downlink subframe starts with a preamble used for synchronization and equalization in the physical layer. Next, the structure of the entire frame is determined through a downlink map (DL-MAP) message and an uplink map (UL-MAP) message in a broadcast form that defines the location and use of bursts allocated to downlink and uplink. define.

The DL-MAP message defines the use allocated for each burst for the downlink period in the burst mode physical layer, and the UL-MAP message defines the use of the burst allocated for the uplink period. The information element constituting the DL-MAP is determined by the downlink interval usage code (DIUC), connection ID (CID), and location information (subchannel offset, symbol offset, subchannel number, symbol number) of the burst. Downlink traffic intervals are divided into.

On the other hand, the information element constituting the UL-MAP message is determined by the Uplink Interval Usage Code (UIUC) for each connection ID (CID), the location of the interval is defined by the duration. Here, the purpose of each section is determined according to the UIUC value used in the UL-MAP, and each section starts at a point separated by the duration defined in the UL-MAP IE from the previous IE start point.

Downlink Channel Descriptor (“DCD”) and Uplink Channel in order for the mobile terminal to enter the network (Network Entry) or for network re-entry due to handover or other reasons. Receive Uplink Channel Descriptor (UCD). The base station periodically informs the mobile station of downlink and uplink physical channel characteristics through the DCD and the UCD.

Table 1 shows an example of the DCD message.

Syntax Size Notes DCD_Message_Format () { Management Message Type = 1 8 bits Downlink channel ID 8 bits Configuration Change Count 8 bits TLV Encoded information for the overall channel variable TLV specific Begin PHY Specific Section { See applicable PHY section. for ( i = 1; i <= n ; i ++) { For each Downlink burst profile 1 to n . Downlink_Burst_Profile variable PHY specific } } }

Table 2 shows an example of a UCD message.

Syntax Size Notes UCD_Message_Format () { Management Message Type = 0 8 bits Configuration Change Count 8 bits Ranging Backoff Start 8 bits Ranging Backoff End 8 bits Request Backoff Start 8 bits Request Backoff End 8 bits TLV Encoded information for the overall channel variable TLV specific Begin PHY Specific Section { See applicable PHY section. for ( i = 1; i <= n ; i ++) { For each uplink burst profile 1 to n . Uplink_Burst_Profile variable PHY specific } } }

The DCD / UCD message includes physical layer related parameters to be applied to burst intervals allocated to downlink and uplink, respectively. Examples of the physical layer parameters include a modulation type and a forward error correction; Here is the code type 'FEC'. In addition, necessary parameters (eg, K, R values, etc. of the R-S code) are defined according to the FEC code type.

The parameters include an uplink interval usage code included in a downlink burst profile (Downlink_Burst_Profile) and an uplink burst profile (Uplink_Burst_Profile) in a UCD (hereinafter referred to as 'UIUC') or a downlink interval use code ( Downlink Interval Usage Code (hereinafter referred to as 'UIUC'). That is, downlink burst profile information included in the DCD defines the characteristics of the physical layer used for a specific burst using the corresponding DIUC.

Table 3 shows an example of a downlink burst profile.

Syntax Size Notes Downlink_Burst_Profile {  Type = 1 8 bits  Length 8 bits  Reserved 4 bits Shall be set zero  DIUC 4 bits  TLV encoded information Variable }

As in the example of Table 3, the downlink burst profile (Downlink_Burst_Profile) includes a 4-bit long DIUC. Since the DIUC has 4 bits of information, 16 different information can be mapped, and the FEC code type can be mapped to the DIUC having a value of 0 to 12, respectively.

Meanwhile, downlink burst profile information included in the UCD defines characteristics of a physical layer used for a specific burst using a corresponding UIUC.

Table 4 shows an example of an uplink burst profile.

Syntax Size Notes Uplink_Burst_Profile {  Type = 1 8 bits  Length 8 bits  Reserved 4 bits Shall be set to zero  UIUC 4 bits  TLV encoded information variable }

As in the example of Table 4, the downlink burst profile includes a 4-bit UIUC. Since the UIUC has 4 bits of information, 16 different information can be mapped, and the FEC code type can be mapped to the DIUC having a value of 0 to 10, respectively.

Table 5 and Table 6 show an example of the TLV configuration of the downlink burst profile.

Table 7 shows an example of a TLV configuration of an uplink burst profile.

The base station configures a downlink burst profile by mapping the FEC coding methods shown in Table 4 to 13 DIUCs. The mapping method is determined by negotiating a coding method supported by the mobile terminal through the SBC-REQ / RSP process and using the result.

Table 8 and Table 9 are examples of modulation and demodulation schemes that the mobile terminal can support.

In the FEC coding type, since the base station uses CC and the DIUC can be mapped to 16 pieces of information, up to six of the DIUCs (DIUC values 0 to 5) are mapped to the CC type. Block Turbo Coding (BTC), Convolutional Turbo Code (CTC), Zero Tail Convolution Code (ZTCC) and low density Selectively map among parity codes (LDPC). Even in the case of UIUC, up to six (UIUC values 0 to 5) are mapped to CC types, and the rest are selectively mapped among BTC, CTC, ZT CC, and LDPC.

The base station configures a downlink burst profile based on the received signal quality of each mobile station. That is, by using channel quality information (CQI) transmitted from each mobile station, an appropriate downlink burst profile (or adaptive modulation and coding) according to the channel state of each mobile station; Hereinafter, 'AMC') is configured. Meanwhile, as a supplementary means, the downlink burst profile may be changed through the DBPC-REQ / RSP & RNG-REQ / RSP process.

1 is an exemplary diagram illustrating a threshold for changing a burst profile. The mobile terminal measures the signal-to-noise ratio (e.g. C / (N + I)) and compares it with the average value for the allowed operating range. The operating range is limited by threshold levels. That is, if the received signal-to-noise ratio is outside of the allowed operating range, the mobile station requests a change to a new burst profile using a downlink burst profile change (DBPC) method. Depending on whether the mobile terminal requests a more robust profile (e.g. QPSK) or a less robust profile (e.g. 64QAM), the base station may actually Performs message transmission and reception for the change of the modulation scheme.

According to the existing technology, when there are several types of coding that a mobile station can support within a service support range of a base station, a downlink burst profile fixed at 13 DIUC values and an uplink fixed at 10 UIUC values are currently fixed. In the case of supporting various types of coding using the link burst profile, a signal-to-noise ratio (SNR) interval corresponding to each AMC is increased, so that a modulation scheme that can be provided for one coding scheme is provided. This decreases.

For example, the base station supports all of the coding schemes of CC, CTC, BTC, ZT CC, and LDPC mentioned above, and when the mobile stations request CC, CTC, LDPC, etc. coding schemes within the service support range, Thirteen DIUCs and ten UIUCs are divided into four groups and assigned to each coding scheme. Therefore, the modulation scheme that can be provided within each coding scheme is reduced. That is, the interval of the threshold for changing the AMC is increased for each coding scheme, there is a problem that the AMC can not be applied properly according to the channel situation.

An object of the present invention is to efficiently apply AMC even when a plurality of coding schemes are supported in a broadband wireless access system.

The present invention for achieving the above object is at least one burst profile including information on the coding type and information on the adaptive modulation and coding (AMC) corresponding to the information on the coding type And receiving data, performing a coding type negotiation that can be supported by the base station, and performing data transmission / reception using a burst profile according to the negotiation result.

The above-mentioned objects, features and advantages will become more apparent from the following detailed description in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Regarding each term described in the embodiment of the present invention, reference may be made to an IEEE 802 document.

A first embodiment of the method for generating a burst profile is as follows. As many as the number of DIUCs / UIUCs to be set are mapped to each DIUC / UIUC value as a TLV value, one FEC code type and a threshold value as a reference for a burst profile change request. In this case, the burst profile includes information on a coding type for indicating whether the burst profile is a burst profile.

Table 10 shows an example of a downlink burst profile according to the present invention.

Syntax Size Notes Type = 1 8bits Length 8bits Reserved 1bits Shall be set to zero Coding type 3bits 000: reserved
001: CC
010: BTC
011: CTC
100: ZT CC
101: LDPC A
110: LDPC B
111: reserved DIUC 4bits TLV encoded information Variable

Table 11 shows an example of an uplink burst profile according to the present invention.

Syntax Size Notes Type = 1 8bits Length 8bits Reserved 1bits Shall be set to zero Coding type 3bits 000: reserved
001: CC
010: BTC
011: CTC
100: ZT CC
101: LDPC A
110: LDPC B
111: reserved UIUC 4bits TLV encoded information Variable

2 is a diagram illustrating an embodiment of a method of mapping AMC to DIUC for each coding scheme. The base station basically supports the CC scheme among various coding types. Accordingly, as illustrated in FIG. 2, DIUC values 0 to 5 and UIUC values 1 to 6 may be allocated to the CC scheme (21). That is, in Table 10, the Coding Type field is set to 001, and AMC is mapped to six DIUC / UIUC values, respectively.

Meanwhile, the base station allocates DIUCs 6 to 12 to other coding schemes in addition to DIUCs 0 to 5 allocated to CCs to support other coding types. For example, when BTC is supported in addition to the CC, in Table 10, the Coding Type field is set to 010 and DIUC 6 to 12 are mapped to AMC (22). In addition, if CTC or LDPC is also supported, the Coding Type fields are set to 011 and 101, respectively, and the respective DIUCs 6 to 12 are mapped to AMC (23 and 24).

Table 12 shows another example of a downlink burst profile according to the present invention.

Syntax Size Notes Type = 1 8bits Length 8bits Reserved 1bits Shall be set to zero Code type set 3bits 000: reserved
001: CC + BTC
010: CC + CTC
011: CC + ZT CC
100: CC + LDPC A
101: CC + LDPC B
110-111: reserved DIUC 4bits TLV encoded information Variable

Table 13 shows another example of an uplink burst profile according to the present invention.

Syntax Size Notes Type = 1 8bits Length 8bits Reserved 1bits Shall be set to zero Code type set 3bits 000: reserved
001: CC + BTC
010: CC + CTC
011: CC + ZT CC
100: CC + LDPC A
101: CC + LDPC B
110-111: reserved UIUC 4bits TLV encoded information Variable

FIG. 3 is a diagram for explaining another embodiment of a method of mapping AMC to DIUC for each coding scheme. FIG. As shown in FIG. 3, a burst profile may be configured using a combination of each coding type. Since the base station basically supports the CC scheme among various coding types, the base station sets the Code Type Set field according to an additionally supported coding type. For example, when supporting CC and BTC, set the Code Type Set field to 001. Then, DIUC values 0 to 5 and UIUC values 1 to 6 are allocated to the CC method, and DIUC 6 to 12 are allocated to the BTC method (31).

As shown in FIG. 3, when the CC and the CTC are supported, the Code Type Set field is set to 010. Then, the DIUC values 0 to 5 and the UIUC values 1 to 6 are allocated to the CC scheme, and the DIUC 6 to 12 are allocated to the CTC scheme (32). On the other hand, when supporting CC and LDPC, set the Code Type Set field to 100. Then, DIUC values 0 to 5 and UIUC values 1 to 6 are allocated to the CC scheme, and DIUC 6 to 12 are allocated to the LDPC scheme (33).

4 is a flowchart illustrating a method of applying a burst profile according to the present invention. The mobile station receives a burst profile generated based on each coding type through UCD / DCD (S41). The mobile terminal negotiates a coding type that can be supported through the SBC-REQ / RSP process with the base station (S42, S43), and as a result of the negotiation, the DIUC value corresponding to 'Coding Type' or 'Code Type Set' that the mobile terminal can support is determined. Recognize (S44). The mobile station receives all of the burst profiles generated based on each coding type through UCD / DCD, but if it is determined, for example, by LDPC, as a result of negotiating supportable coding type with the base station, the mobile station allocates the burst profile to the mobile station. The AMC is applied to the burst based on the CC and the LDPC, and receives a signal from the base station according to the applied AMC (S45).

In addition to the above-described embodiments, the IE of DL-MAP / UL-MAP can be used to inform the mobile terminal using a specific coding type of the new coding type. Meanwhile, whenever a new coding scheme is added through the extended DIUC / UIUC, the new FEC code type may be notified through the extended DIUC to all mobile terminals.

5 is another exemplary flowchart illustrating a burst profile applying method according to the present invention. This embodiment is an example of the case where the mobile terminal supports one basic coding scheme and two newly added enhanced coding schemes. The mobile station reports its supportable coding scheme to the base station through the SBC-REQ message (S51), and the base station informs the mobile terminal of the coding scheme to support either of them through the SBC-RSP (S52). In order to apply the DIUC / UIUC, the mobile station interprets the value of the DIUC / UIUC of the burst profile included in the DCD received from the base station into a coding type designated by the base station.

That is, as shown in FIG. 5, when the mobile terminal uses CC as a base and supports CTC and LDPC, two coding schemes are reported through SBC-REQ, and the base station reports one of the LDPC schemes. You will be notified via SBC-RSP. And, the mobile terminal interprets the value of DIUC / UIUC according to LDPC.

The 'type' field included in DCD / UCD enables the identification of the type of information required by the mobile terminal. For example, in the burst profile format shown in Tables 3 and 4, the type field is fixed to '1'. In the case of a conventional mobile terminal, it is determined that it is a burst profile through the type field. In the case of a burst profile including a conventional basic coding method, a burst profile that uses a value of '1' in the type field and applies a new type to indicate the inclusion of a new coding type is constructed. use.

Table 14 shows an example of a downlink burst profile.

Syntax Size Notes Downlink burst profile { Type = 153 8 bits Length 8 bits Reserved 2 bits Shall be set to zero Coding type 2 bits 00: BTC
01: CTC
10: ZT CC
11: LDPC DIUC 4 bits TLV encoded information Variable }

Similar to when the type field has a value of '1', the type field configures a downlink burst profile having a value of '153'. The mobile terminal can know the AMC level mapping of the underlying CC through a burst profile having a type field of '1'. On the other hand, when the type field receives a burst profile having a value of '153', only the coding scheme of the mobile station can be selected.

Table 15 shows an example of an uplink burst profile.

Syntax Size Notes Uplink burst profile { Type = 13 8 bits Length 8 bits Reserved 2 bits Shall be set to zero Coding type 2 bits 00: BTC
01: CTC
10: ZT CC
11: LDPC UIUC 4 bits TLV encoded information Variable }

Table 16 is an example which shows the value contained in UCD.

Name Type
(1 byte) Length
(1 byte) Value
(variable-length) PHY scope Bandwidth_request_backoffb_start 11 One Initial backoff window size for contention
BW requests, expressed as a power of 2.
Values of n range 0-15 (the highest order
bits shall be unused and set to 0). OFDMA Bandwidth_request_backoff_end 12 One Final backoff window size for contention
BW requests, expressed as a power of 2.
Values of n range 0-15 (the highest order
bits shall be unused and set to 0). OFDMA Uplink_burst_profile 13 One May appear more than once (see 6.3.2.3.3 and 8.4.5.5). The length is the number of bytes in the overall object, including embedded TLV items. OFDMA

Table 17 is an example which shows the value contained in DCD.

Name Type
(1 byte) Length
(1 byte) Value
(variable-length) PHY scope Time-to-Trigger duration
52 One Time-to-Trigger duration is the time duration for MS decides to select a neighbor BS as a possible target BS. It is the unit of ms and applicable only for HHO. ALL MAC version 148 One See 11.1.3 ALL Downlink_burst_profile 153 One May appear more than once (see 6.3.2.3.1 and 8.4.5.5). The length is the number of bytes in the overall object, including embedded TLV items. OFDMA

As in the examples of Tables 16 and 17, the value of the type field included in the DCD or the UCD can be analyzed. As described above, when the value of the type field is defined, the existence of a new burst profile can be known using DCD or UCD, in addition to the burst profile indicated by the type value as 1.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention has the effect of efficiently applying AMC even when supporting a plurality of coding schemes.

Claims (10)

A method of supporting multiple coding types in a wireless mobile communication system, The mobile station receiving a downlink channel descriptor (DCD) from a base station, the DCD including at least one downlink burst profile, the downlink burst profile being a type field of the downlink burst profile, a downlink A link interval use code (DIUC) field and a TLV Encoded Information field, wherein a value of the type field of the at least one downlink burst profile is a coding type field; Determining whether the DCD is included in the at least one downlink burst profile; And The mobile station recognizing the coding type field when the coding type field is included in the at least one downlink burst profile, wherein the coding type field is a downlink associated with the at least one downlink burst profile by the base station. The coding type field recognition step, which indicates a coding scheme to use for coding a link burst, The coding scheme is at least one of block turbo coding (BTC), convolutional turbo code (CTC), zero tail convolutional code (ZTCC) and low density parity code (LDPC), If the value of the type field of the at least one downlink burst profile is 1, the at least one downlink burst profile does not include the coding type field, and the downlink associated with the at least one downlink burst profile The link burst is coded by the coding scheme of the convolutional code (CC), When the value of the type field of the at least one downlink burst profile is 153, the at least one downlink burst profile includes the coding type field indicating the coding scheme, and the downlink burst is the coding Coded by a coding scheme indicated by a type field, And the DIUC field for the CC is associated with the at least one downlink burst profile in which a value of a type field is set to one. The method of claim 1, The TLV encoded information includes a forward error correction (FEC) code type, a DIUC mandatory exit threshold, and a DIUC minimum entry threshold. The method of claim 1, If the value of the type field of the at least one downlink burst profile is 153, the coding type field of the at least one downlink burst profile supports multiple coding types for multiple coding schemes. Way. The method of claim 1, And if the value of the type field of the at least one downlink burst profile is 153, the at least one downlink burst profile is included in the DCD for a specific downlink burst of the mobile station. The method of claim 1, And if the value of the type field of the at least one downlink burst profile is 153, only the coding scheme possessed by the mobile station is selected by the mobile station. A mobile station supporting multiple coding types in a wireless mobile communication system, A receiver for receiving a downlink channel descriptor (DCD) from a base station, wherein the DCD includes at least one downlink burst profile, wherein the downlink burst profile is a type field of the downlink burst profile, a downlink period A usage code (DIUC) field and a TLV Encoded Information field, wherein a value of the type field of the at least one downlink burst profile is a coding type field; Determining whether the receiver is included in at least one downlink burst profile; And A processor for recognizing the coding type field when the coding type field is included in the at least one downlink burst profile, wherein the coding type field is determined by the base station of a downlink burst associated with the at least one downlink burst profile. Including the processor for indicating a coding scheme to use for coding, The coding scheme is at least one of block turbo coding (BTC), convolutional turbo code (CTC), zero tail convolutional code (ZTCC) and low density parity code (LDPC), If the value of the type field of the at least one downlink burst profile is 1, the at least one downlink burst profile does not include the coding type field, and the downlink associated with the at least one downlink burst profile The link burst is coded by the coding scheme of the convolutional code (CC), When the value of the type field of the at least one downlink burst profile is 153, the at least one downlink burst profile includes the coding type field indicating the coding scheme, and the downlink burst is the coding Coded by a coding scheme indicated by a type field, And the DIUC field for the CC is associated with the at least one downlink burst profile in which the value of the type field is set to one. The method of claim 6, The TLV encoded information includes a forward error correction (FEC) code type, a DIUC mandatory exit threshold, and a DIUC minimum entry threshold. The method of claim 6, If the value of the type field of the at least one downlink burst profile is 153, the coding type field of the at least one downlink burst profile supports a plurality of coding types for multiple coding schemes. Lee Dong-guk. The method of claim 6, And if the value of the type field of the at least one downlink burst profile is 153, the at least one downlink burst profile is used in the DCD for the mobile station only. The method of claim 6, And if the value of the type field of the at least one downlink burst profile is 153, only the coding scheme possessed by the mobile station is selected by the mobile station.

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