BRPI0517319B1 - APPARATUS AND METHOD FOR TRANSMITING / RECEIVING PACKAGE DATA SYMBOL IN A MOBILE COMMUNICATION SYSTEM - Google Patents

Abstract

apparatus and method for transmitting / receiving packet data symbol in a mobile communication system. an apparatus and method for transmitting a packet data symbol in a high speed mobile packet data (hrpd) communication system for broadcast service. A transmission processor generates a modulated symbol by encoding, interlacing, and modulating a physical layer packet to be transmitted, and arranging the modulated symbol in a data tone. the tone inserter inserts a guard tone and a pilot tone within the data tone. the tone energy allocator sets a different data pilot-to-tone energy ratio according to the position of a range, where the packet data symbol is included, and allocates energy according to the pilot energy ratio -to-tone data. The transmitter transmits the packet data symbol.

Description

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an apparatus and method for improving reception performance in an HRPD mobile communication system based on an OFDM transmission scheme.

It is another object of the present invention to provide an apparatus and method for adjusting the energy allocated to pilot tones according to the position of an OFDM symbol in an HRPD mobile communication system based on an OFDM transmission scheme.

According to an exemplary aspect of the present invention, an apparatus is provided for transmitting a packet data symbol in the high speed mobile packet data (HRPD) communication system to a broadcast service. The apparatus comprises a transmission processor for generating a modulated symbol by encoding, interlacing and modulating a physical layer packet to be transmitted, and arranging the modulated symbol in a data tone; a tone inserter to insert a guard tone and a pilot tone within the data tone; a tone energy allocator to fix a different proportion of pilot-to-data tone energy according to an interval position, in which the packet data symbol is included, and allocate energy according to the proportion of

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pilot-to-data tone energy; and a transmitter for transmitting the packet data symbol.

According to another exemplary aspect of the present invention, a method is provided for transmitting a packet data symbol in the high speed mobile packet data (HRPD) communication system to a broadcast service. The method comprises the steps of: generating a modulated symbol when encoding, interlacing and modulating a physical layer package to be transmitted, and arranging the modulated symbol in a data tone; insert a guard tone and a pilot tone within the data tone; set a different proportion of pilot-to-data energy according to the position of the interval, in which the packet data symbol is included, and allocate energy according to the proportion of pilot-to-data energy tone ; and transmitting the packet data symbol.

In accordance with yet another exemplary aspect of the present invention, a method is provided for receiving a packet data symbol in a high speed mobile packet data (HRPD) communication system for a broadcast service. The method comprises the steps of: when receiving information in a pilot-to-data energy ratio determined according to the position of the packet data symbol, storing the pilot-to-data energy proportion of according to the position of the symbol; if the package received in an orthogonal frequency division (OFDM) multiplexing package, extract a data symbol from an OFDM package and scatter the extracted data symbol, thus extracting a data tone and a pilot tone; estimate a channel using the ratio of

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pilot-to-data energy of the OFDM package; and restoring the data tone data using the channel estimation information.

In accordance with yet another exemplary aspect of the present invention, an apparatus is provided for receiving a packet data symbol in a high speed mobile packet data (HRPD) communication system for a broadcast service. The apparatus comprises a channel estimation unit for receiving a control message, extracting a pilot-to-data energy ratio according to the position of the packet data symbol, determining the channel estimation weight, and estimating the channel according to the pilot tone-to-data energy ratio; an orthogonal frequency division multiplexing (OFDM) processor to divide the received OFDM symbol into a pilot tone and a data tone, supply the pilot tone to the channel estimation unit, and output the data tone; and a data restoration unit for restoring information transmitted from the data tone using the channel estimation information provided from the channel estimation unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The above exemplary objectives and other exemplary objectives, resources and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which equal reference numbers will be understood as referring to parts, components and equal structures, where:

Figure 1 is a diagram that illustrates a format of

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05Α

downlink interval in a conventional HRPD mobile communication system.

Figure 2 is a diagram illustrating the interval format provided when inserting an OFDM symbol in a data transmission interval of an interval in the downlink HRPD for a BCMCS service.

Figure 3 is a diagram that illustrates a conventional tone arrangement method in an HRPD system.

Figure 4 is a block diagram that illustrates a conventional transmitter structure in a system

HRPD.

Figure 5A is a diagram illustrating the format for transmitting a BCMCS OFDM interval between CDM intervals.

Figure 5B is a diagram illustrating the format for transmitting a BCMCS OFDM interval between BCMCS intervals

OFDM.

Figure 6 is a block diagram illustrating the structure of a transmitter in an HRPD system for a broadcast service according to an exemplary version of the present invention.

Figure 7 is a flow chart illustrating the operation of a transmitter in an HRPD system for a broadcast service in accordance with an exemplary version of the present invention.

Figure 8 is a flow chart illustrating the operation of a receiver in an HRPD system for a broadcast service in accordance with an exemplary version of the present invention.

Figure 9 is a diagram illustrating an exemplary slot format for transmitting BCMCS OFDM slots consecutively between CDM slots.

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Figure 10 is a flow chart illustrating the operation of a transmitter in an HRPD system to radiate service in accordance with another exemplary version of the present invention.

Figure 11 is a flow chart illustrating the operation of a receiver in an HRPD system for a broadcast service in accordance with another exemplary version of the present invention.

Figure 12 is a block diagram illustrating the structure of a receiver for receiving an OFDM signal that the transmitter transmits after setting a different energy ratio depending on the position of an OFDM symbol, according to an exemplary version of the present invention. AND

Figure 13 is a flow chart illustrating the process of receiving an OFDM signal at a receiver in an HRPD system according to an exemplary version of the present invention. DETAILED DESCRIPTION OF EXAMPLE VERSIONS

Several exemplary versions of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, as noted above, the same or similar elements are denoted by the same reference numbers, although they are represented in different drawings. In the following description, a detailed description of functions and configurations known here incorporated has been omitted for clarity and conciseness.

In a system that uses an HRD-compliant OFDM transmission scheme, BCMCS intervals may not be transmitted continuously. Therefore, the performance of the channel estimation depends on whether the OFDM symbols are located at the boundaries of the range or at the center of the range. OFDM symbols located at the borders of the

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interval are lower than the OFDM symbols located in the center of the interval in terms of channel estimation performance. That is, since the same value is used for the R ratio of energy allocated to individual pilot tones to the energy allocated to the individual data tones regardless of the positions of the OFDM symbols, the probability of error for the OFDM symbols located at the boundary of the range increases.

Therefore, an exemplary version of the present invention provides a method for adjusting the energy allocated to the pilot tones according to the position of the gap, thereby improving reception capacity.

In general, an increase in pilot tone energy improves channel estimation performance. However, as the total transmission energy used as pilot tone energy and data tone energy is limited, an increase in energy for pilot tones causes a decrease in energy for data tones. The decrease in energy for data tones leads to an increase in the probability of error in a data decoding process. Therefore, for the total transmission energy given, there is a need for a balance between the energy to be allocated to the pilot tones and the energy to be allocated to the data tones.

In operation, a proportion of R_Side energy to be used in OFDM symbols located at the boundaries of the range and the proportion of R_Center energy to be used in OFDM symbols located at the center of the range must be predefined in a transmit / receive interval. For the proportions of energy R_Side and R__Center, the terminal

18/46 can use either its initial values or the values notified from a base station before receiving a BCMCS interval. That is, as the optimum values R_Side and R_Center differ according to the channel conditions, these values are predefined in the transmission / reception period. In a fast fading environment, it is preferable to set R_Side and R_Center to higher possible values because the channel estimation performed using pilot tones on another symbol may show low reliability.

Figure 6 is a block diagram illustrating the structure of a transmitter in an HRPD system for a broadcast service according to an exemplary version of the present invention.

The transmitter includes a channel encoder 301 for channel encoding the received packet data, a channel interleaver 302 for interlacing the encoded packet data, a modulator 303 for modulating the interlaced packet data, a guard tone inserter 304 for insert guard tones into the signal output of the modulator 303, and a pilot tone insert 305 to insert pilot tones into the signal emitted from the guard tone insert 304. In addition, the transmitter includes a 606 tone power allocator, a QPSK spreader 3 07, an IFFT 3.08 unit, a CP 309 inserter, and an HRPD 310 compatible processor.

The operation of the transmitter will now be described in detail with reference to Figure 6.

The physical layer packet data generated in an upper layer is entered in channel encoder 301, channel encoder 301 encodes channel data by channel

19/46 packet in a channel-encoded bit stream, and output the channel-encoded bit stream to channel interleaver 302. Channel interleaver 302 interlaces (or exchanges columns) in the channel-encoded bit stream to achieve diversity gain, and output the interlaced bit stream to modulator 3 03. Modulator 3 03 modulates the interlaced bit stream in a modulation signal. The modulation signal is arranged in data tones

203.

guard tone inserter 304 arranges the signal emitted from modulator 303 in guard tones 201 located on the edges of a band, and pilot tone inserter 305 arranges pilot tones 202 in the signal emitted from guard tone inserter 304 at regular intervals.

Thereafter, the tone energy allocator 606 adjusts the energy allocated to the pilot tones depending on the position of the corresponding symbols, that is, whether the corresponding OFDM symbols are located at the boundary of the range or in the center of the range. This will be described in more detail with reference to Figure 5A. For OFDM symbols 121 and 124 located at the boundary of the range, the energy for the pilot tones and the data tones are allocated using the R_Side energy ratio. For the OFDM 122 and 123 symbols located in the center of the range, the energy for the pilot tones and the data tones are allocated using the R_Center energy ratio. As described above, in an exemplary implementation, the values for R_Side and R__Center are predefined.

The transmission signal, after being allocated to all

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tones, is subjected to QPSK spreading on the QPSK 307 spreader. The IFFT 308 unit arranges the modulation signals spread across the QPSK at desired frequency tone positions through an IFFT process. Thereafter, the CP 309 inserter inserts a CP into the signal emitted from the IFFT 3 0 8 unit, completing the generation of an OFDM transmission signal.

An exemplary version of the present invention establishes a variable pilot tone-to-data energy ratio (i.e., a variable pilot tone energy to data tone energy ratio) according to the position of the OFDM symbols. Alternatively, however, it is also possible to establish a fixed energy ratio for a particular position of an OFDM symbol. According to an exemplary implementation of the present invention, the HRPD system uses the variable energy ratio and not the fixed energy ratio because OFDM symbols may not be transmitted at all intervals.

To use the variable energy ratio and not the fixed energy ratio, the base station transmits information about the energy proportion based on the position of an OFDM symbol to a terminal using a signaling message (for example, the BroadcastOverhead message) used to support the BCMCS service in the HRPD system, to inform the terminal of the current pilot-to-data tone energy ratio.

To variably establish the pilot-to-data tone energy ratio, the following two exemplary versions can be taken into account.

In a first version, the base station provides the

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terminal information indicating a proportion of pilot-to-data tone energy, commonly applied in the range where OFDM symbols are transmitted. The format of the signaling message used by the base station to inform the terminal of the common energy proportion in the first version is shown in Table 1.

Table 1

Field Length (bits) [. . .] . .] Dua1PDREnabled 1 EBCMCSTransmissionFormat 0 or N PCPilotToDataGain 0 or N DualPDREnabledForThisLogicalChannel 1 ACPilotToDataGainRecord Ο, Ν, 2N, or 4N [. . .] [. . .]

Table 1 illustrates only those fields used in an exemplary version of the present invention, and omits other fields used to support the BCMCS service. The signaling message shown in Table 1 is configured to indicate a pilot-paradigm energy ratio for two types of symbols. The HRPD system, on the assumption that four OFDM symbols are transmitted over an interval, can indicate the proportion of pilot-to-data tone energy for each of the OFDM symbols. However, as the two symbols located in the center of the range are similar in character to the two symbols located at the boundaries of the range, the pilot-to-data tone energy ratio is indicated such that the signal message load can be reduced. Each signaling message field shown in Table 1 will be described

22/46 now below.

The 'DualPDREnabled' field indicates whether a ratio of energy tone energy to pilot tone data (Dual pilot-to-data energy ratio (Dual PDR)) for both types of symbols is used or not. If this field value is set to '1', it means that the Dual PDR is used. However, if this field value is fixed at Ό ', it means that only the pilot-to-data tone energy ratio for a type of symbols is used.

The 'EBCMCSTransmissionFormat' field indicates the formation of the transmission. If the most significant bit (MSB) in this field is set to Ό ', it means that a transmission format is used that does not support the variable format. However, if the MSB of this field is set to Ί ', it means that the transmission format that supports the variable format is used. The variable format, when transmitting multiple intervals, allows each individual interval to transmit OFDM symbols in other formats. According to an exemplary implementation of the present invention, the format of the OFDM symbols for the variable format is defined with the size of a CP, the number of pilot tones, and the number of guard tones. That is, by supporting the variable format, it is possible to transmit ODM symbols to which a CP, pilot tones and guard tones are applied, all having different sizes (or lengths), for each individual interval. Therefore, the individual ranges may differ by the appropriate PDR value. When supporting variable format for this reason, it is necessary to establish a different PDR value

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• ** · »* · * • * · · * * ·· ·· tone ratio of data before and after format change.

The 'DCPilotToDataGain' field indicates the DC pilot tone energy to the energy of (ie the ratio of pilot tone energy to DC data). In the first exemplary version of the present invention, as a Dual PDR is supposed to be applied only to alternating current (AC) pilot tones, a single value

DCPilotToDataGain is defined.

The 'DualPDREnabledForThisLogicalChannel' field indicates whether a corresponding logical channel includes a Dual PDR. If this field value is set to '1', the corresponding logical channel uses a Dual PDR, indicating that the field related to the Dual PDR will be defined through this field. However, if this field value is set to '0', it means that the corresponding logical channel does not use Dual PDR.

The 'ACPilotToDataGainRecord' field indicates the ratio of AC pilot tone energy to data tone energy (that is, a ratio of pilot tone energy to AC data). If the 'DualPDREnabledForThisLogicalChannel' field is set to '0', indicating that Dual PDR is not used, the 'ACPilotToDataGainRecord ⁷ field is expressed in the format shown in Table 2A or Table 2B

Table 2A

Field Length (bits). ACPilotToDataGain N

Table 2B

Field Length (bits) ACPilotToDataGainl N ACPilotToDataGain2 N

24/46 tone energy the variable shape • · • · ·· ** • · ·· »

*

Table 2A illustrates the pilot-to-CA data ratio for the case where it is not used and Table 2B illustrates a pilot-to-data AC power ratio for the case where the variable format is used.

Table 2A illustrates how to express the 'ACPilotToDataGainRecord' field when the 'DualPDREnabledForThisLogicalChannel' field is set to '0' and a _z

MSB in the 'EBCMCSTransmissionFormat' field is set to '0', i

that is, Dual PDR and variable format are not used.

The 'ACPilotToDataGain' field indicates a ratio of pilot tone energy to AC data, and is set to the same value regardless of the position of the corresponding symbol.

Table 2B illustrates how to express the 'ACPilotToDataGainRecord' field when the 'DualPDREnabledForThisLogicalChannel' field is set to Ό 'and the MSB in the' EGBCMCSTransmissionFormat 'field is set to Ί', that is, Dual PDR is not used and the variable format is used. The 'ACPilotToDataGainl' field indicates the proportion of AC pilot-to-data energy before a change in the transmission format, and the 'ACPilotToDataGain2' field indicates a proportion of AC pilot-to-data energy after the change in transmission. transmission format, and is set to the same value regardless of the position of the corresponding symbol.

If the field 'DualPDREnabledForThisLogicalChannel' is set to '1', indicating that Dual PDR is used, the field 'ACPilotToDataGainRecord' is expressed in the format shown in Table 2C or Table 2D.

Table 2C

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Field Length (in bits) ACInternalPilotToDataGain N ACBoundaryPilotToDataGain N

2D Table

Field Length (in bits) ACInternalPilotToDataGainl N ACBoundaryPilotToDataGainl N ACInternalPilotToDataGain N ACBoundaryPilotToDataGain N

Table 2C illustrates the proportion of pilot tone energy for AC data for the case in which the variable format is not used, and Table 2D illustrates the proportion of pilot tone energy for AC data for the case in which the variable format is used.

Table 2C illustrates how to express the 'ACPilotToDataGainRecord' field when the 'DualPDREnabledForThisLogicalChannel' field is set to '1' and the MSB in the 'EBCMCSTransmissionFormat' field is set to '0', that is, Dual PDR is used and the variable format is not used. The 'ACInternalPilotToDataGain' field includes a pilot-to-data energy ratio value used for the transmission of center symbols between the OFDM symbols transmitted by an interval, and the 'ACBoundaryPilotToDataGain' field includes a power proportion value of pilot-to-data tone used for the transmission of boundary symbols between OFDM symbols transmitted by an interval.

Table 2D illustrates how to express the 'ACPilotToDataGainRecord' field when the 'DualPDREnabledForThisLogicalChannel' field is set to Ί 'and the

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4ο

MSB in the 'EBCMCSTransmissionFormat' field is set to Ί ', that is, both the Dual PDR and the variable format are used. The 'ACInternalPilotToDataGain' field and the 'ACBoundaryPilotToDataGainl' field include a pilot-to-data energy ratio value used for the transmission of the center symbols between the OFDM symbols transmitted over an interval, and the energy proportion ratio of pilot-to-data tone used for the transmission of boundary symbols between the OFDM symbols transmitted by an interval, respectively, and are used before a change in the transmission format.

the 'ACInternalPilotToDataGain2' field and the 'ACBoundaryPilotToDataGain2' field include a pilot-to-data tone energy ratio value used for the transmission of the center symbols between the OFDM symbols transmitted by an interval, and the tone energy ratio value pilot-to-data used for the transmission of boundary symbols between the OFDM symbols transmitted by an interval, respectively, and are used after changing the transmission format.

The 'ACInternalPilotToDataGain2 ^/ field and the' ACBoundaryPilotToDataGain2 'field include a pilot-to-data energy ratio value used for the transmission of the center symbols between the OFDM symbols transmitted by an interval, and the energy proportion value of pilot-to-data tone used for the transmission of the boundary symbols between the OFDM symbols transmitted by an interval, respectively, and are used after changing the transmission format.

In a second exemplary version, the base station

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provides the terminal with information indicating the proportion of pilot-to-data tone energy applied to an interval in which OFDM symbols are transmitted, for each individual interlacing. The HRPD system, which operates on a 4-interval interleaving scheme, can use only one or more interleavings for the transmission of the OFDM symbol. Therefore, during the transmission of the OFDM symbol, the HRPD system can establish a different pilot-to-10 data power ratio value for each individual interlacing.

The signaling message format used by the base station to inform the terminal of the variable pilot-to-data tone energy ratio for each individual interlacing during symbol transmission

OFDM in the second version is shown in Table 3.

Table 3

Field Length (in bits) [-. -] [. . .] PilotToneToDataTonePowerRatiolncluded 1 [...] [. . .] InterlaceOIncluded 1 CenterSymbolsPDTTPRO 0 or N SideSymbolsPDTTPRO 0 or N [. . .3 [. . .] Interlacellncluded 1 CenterSymbolsPDTTPRl 0 or N SideSymbolsPTDTPRl 0 or N [. . .] [. ..] Interlace2Included 1

28/46

CenterSymbolsPDTTPR2 0 or N SideSymbolsPTDTPR2 0 or N [. . .] [. . .] Interlace3Included 1 CenterSymbolsPDTTPR3 0 or N SideSymbolsPTDTPR3 0 or N [. . .]

Table 3 illustrates only the fields used for a version of the present invention, and omits other fields used to support the BCMCS service. The signaling message shown in Table 3 is configured to include a field indicating the ratio of pilot-to-data energy to two types of symbols.

The signaling message can include a field to indicate the pilot-to-data tone energy ratio for each symbol. However, the signaling message includes a field to indicate the ratio of pilot-to-data tone energy to two types of symbols as shown in Table 3, to reduce the burden of the signaling message.

Each signaling message field shown in the

Table 3 will now be described in detail below.

The 'PilotToneToDataTonePowerRationlncluded' field indicates whether or not the pilot tone energy proportion value for data is included. If this field value is set to '0', it means that the pilot-to-data tone energy ratio is not included and a default value is used. However, if this field value is set at Ί ', it means that the proportion of pilot-to-data tone energy used during data transmission

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all OFDM symbols, is included.

The 'InterlaceXIncluded' field indicates whether or not the information to be transmitted using 'Interlaced =' X 'intervals is included. Here, X denotes 0, 1, 2, or 3. If this field value is set to '0', it means that the transmission information is not included and, if this field value is set to '1', this means that the transmission information is included.

The 'CenterSymbolsPTDTPRX (Pilot Tone to Pilot Tone Energy Ratio for Center Symbols transmitted at X interlaced intervals, for X = 0, 1, 2, or 3) field includes a pilot-to- data used for the transmission of center symbols between OFDM symbols transmitted by an interval included in an interlaced X. The 'CenterSymbolsPTDTPRX' field is only included when the 'PilotToneToDataTonePowerRatioIncluded' field is set to '1' and the 'InterlaceXIncluded' field is set to '1'.

field 'SideSimbolsPTDTPRX (Data Tone to Pilot Tone Energy Ratio for Side Symbols transmitted in X interlaced intervals, for X = 0, l, 2, or 3)' indicates a pilot tone energy ratio value for data used for the transmission of boundary symbols between OFDM symbols transmitted by an interval included in an interlaced X. The 'SideSymbolsPTDTPRX' field is included only when the 'PilotToneToDataTonePowerRationlncluded' field is set to '1' and the 'InterlaceXIncluded' field is set to '1'.

N shown in Table 1 to Table 3 is used to indicate a pilot-tone energy ratio value

30/46 for data. This value can be expressed in dB or can be encoded before being transmitted, and its resolution may depend on the size of N.

Referring to Figure 7, a detailed description of a transmitter operation will now be made to establish a different pilot-to-data energy proportion value for the transmission interval according to the position of the OFDM symbols so that the value of Fixed energy ratio can always be used in the position of a particular OFDM symbol, according to an exemplary version of the present invention.

Figure 7 is a flow chart illustrating the operation of a transmitter in an HRPD system for a broadcast service in accordance with an exemplary version of the present invention. In an exemplary version of the present invention, the transmitter in an HRPD system for a broadcast service refers to a base station.

In step 701, the transmitter generates data tones from broadcast data to be transmitted, using a channel encoder 301, a channel interleaver 302 and a modulator 303. The transmitter inserts guard tones within the data tones in step 7 02 , and inserts pilot tones into the data tones with guard tones entered in step 703. The transmitter determines, in step 704, whether a corresponding OFDM symbol is located in the center of an interval or at the interval boundary. If it is determined that the OFDM symbol is located at the boundary of the range, the transmitter allocates energy for pilot tones and data tones according to an R_Side energy ratio in step 705. However, if it is determined that

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·· the OFDM symbol is located in the center of the range, the transmitter allocates energy for pilot tones and data tones according to an energy ratio R_Center in step 706.

Thereafter, in step 707, the transmitter performs different QPSK spreading according to a BCMCS content identifier, using a QPSK 307 spreader. In step 708, the transmitter performs an IFFT process using the IFFT 308 unit, and inserts a CP into of the symbol processed at the IFFT using a CP 309 inserter, completing the OFDM signal. Thereafter, the transmitter performs an HRPD-compatible process using an HRPD 310-compatible processor in step 709, and transmits the completed OFDM signal in step 710.

With reference to Figure 8, a description will now be made of an exemplary process of restoring the broadcast signal at the receiver upon receipt of the OFDM signal generated through the operation of Figure 7.

Figure 8 is a flow chart illustrating the operation of the receiver in an HRPD system for a broadcast service according to an exemplary version of the present invention. In one version of the present invention, the receiver in an HRPD system for a broadcast service refers to a terminal.

In step 801, the receiver receives R_Side and R_Center values from a base station, or from a transmitter. When the R_Side and R_Center values fail to be received, the receiver uses initial values R_Side and R_Center. Upon receipt of a BCMCS interval, the receiver extracts an OFDM symbol from the BCMCS interval received in step 802, and performs QPSK de-spreading on the OFDM symbol extracted at / 0

32/46 ··· • · step 803.

Thereafter, in step 804, the receiver performs the channel estimation and determines whether the OFDM symbol is located at an interval boundary. If the received OFDM symbol is located at the interval boundary, the receiver proceeds to step 805 where it performs the channel estimation according to the pilot tone-to-data energy ratio R_Side.

However, if the received OFDM symbol is located in the center of the range, the receiver proceeds to step 806, where it performs the channel estimation according to a pilot-paradigmed R_Center energy ratio. In the channel estimation processes of steps 805 and 806, the receiver uses pilot tones located in adjacent OFDM symbols. In step 807, the receiver extracts data tones from the estimated channel and demodulates the extracted data tones. In step 808, the receiver finally decodes the demodulated data tones into a broadcast signal transmitted from the transmitter.

In Figures 7 and 8 it was assumed that there were four OFDM symbols in an interval. However, the previous methods can be applied in the same way even though the number of OFDM symbols is modified. In this case, the ratio of pilot-to-data energy to the OFDM symbols located at the boundaries of a range can be fixed to R_Side, and the ratio of pilot-to-data energy to the remaining OFDM symbols located in the center. the interval can be set to R_Center.

Another exemplary version of the present invention will be

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briefly described below. In the exemplary versions described with reference to Figures 5 to 8, it is assumed that a BCMCS OFDM interval has at least one CDM interval adjacent to it. However, when the OFDM range has a CDM range being adjacent to it, the pilot-to-data tone energy ratio only for the OFDM symbols located in the OFDM range being immediately adjacent to the CDM range can be set to R_Side.

Figure 9 is a diagram illustrating an exemplary slot format for transmitting BCMCS OFDM slots consecutively. Reference numbers 412 and 413 represent BCMCS OFDM intervals for transmitting the same broadcast information, and a receiver receives both BCMCS OFDM intervals 412 and 413. However, the BCMCS receiver does not receive CDM intervals 411 and 414. In this situation, the BCMCS receiver can use OFDM symbols of the BCMCS OFDM 413 range in a channel estimation process to demodulate the OFDM 124 symbol. In the exemplary implementation of the present invention, the OFDM symbols 121 and 124, although they are both located at the boundary of the range, energy must be allocated according to different proportions of pilot-to-data energy.

To address a possible problem in this situation, an exemplary version of the present invention can provide an extended method for fixing different proportions of pilot-to-data energy to the individual positions of the OFDM symbols in the range.

format of the signaling message used to indicate the energy proportion is illustrated in Table 4. Table 4 (3

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* * • ♦ ♦ • * · : · ♦ * * · ♦ * · · * * * • * · • * · • »» • * ♦ ♦ * « * • φ • • * * ί · • • « * * ♦ · « * • • «φ * · · <

Field Length (in bits) [. . .] -.] PilotToneToDataTonePowerRatioIncluded 1 [-. .] InterlaceOIncluded 1 FirstSymbolsPTDTPRO 0 or N SecondSymbolsPTDTPRO 0 or N ThirdSymbolsPTDTPRO 0 or N FourthSymbols PTDTPRO 0 or N [...] . J Interlacellncluded 1 FirstSymbolsPTDTPRl 0 or N SecondSymbolsPTDTPRl 0 or N ThirdSymbolsPTDTPRl 0 or N FourthSymbolsPTDTPRl 0 or N [. . .] [. . .] Interlace2Included 1 Fi rst Symbols PTDTPR2 0 or N SecondSymbolsPTDTPR2 0 or N Thi rdSymbols PTDTPR2 0 or N FourthSymbolsPTDTPR2 0 or N [. . .] [. . .] Interlace3Included 1 FirstSymbolsPTDTPR3 0 or N SecondSymbolsPTDTPR3 0 or N ThirdSymbolsPTDTPR3 0 or N FourthSymbolsPTDTPR3 0 or N [. . .3 [. - J

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Table 4 illustrates only the fields used for an exemplary version of the present invention, and omits other fields used to support the BCMCS service. Each field of the signaling message shown in Table 4 will now be described in detail below.

The 'PilotToneToDataTomePowerRatioIncluded' field indicates whether or not a pilot tone energy proportion value for data is included. If this field value is set to '0', it means that the pilot-to-data tone energy ratio is not included and an initially set default value is used. However, if this field value is set to '1', it means that a pilot-to-data tone energy ratio used during the transmission of all OFDM symbols is included.

The 'TnterlaceXIncluded' field indicates whether or not the information to be transmitted using interlaced intervals 'X' is included. Here, X denotes 0, 1, 2, or 3. If this field value is set to '0', it means that the transmission information is not included, and if this field value is set to '1', this means that the transmission information is included.

The field 'FirstSymbolsTPDTPRX {Data Tone Energy Ratio for Pilot Tone for First Symbols transmitted in X interlacing intervals, for X = 0, 1, 2, or 3) includes a pilot-to-tone energy ratio value -data used for the transmission of the first symbols in a corresponding interval, such as the OFDM 121 symbol in Figure 9, between the OFDM symbols transmitted by an interval. The field

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· <'FirstSymbolsPTDTPRX ⁷ is included only when the' PilotToneToDataTonePowerRatioIncluded ⁷ field is set to '1' and the 'InterlaceXIncluded' field is set to '1'.

field 'SecondSymbolsPTDTPRX (Data Tone to Pilot Tone Energy Ratio for Seconds Symbols Transmitted in interlaced intervals X to X = 0, 1, 2, or 3)' includes the value of the pilot-to-data tone energy ratio used for the transmission of the second symbols in a corresponding interval, such as the OFDM 122 symbol in Figure 9, between the OFDM symbols transmitted by an interval. The 'SecondSymbolsPTDTPRX ⁷ field is included only when the' PilotToneToDataTonePowerRatioIncluded field for Third Symbols transmitted in interlaced intervals X, for X = 0, 1, 2, or 3) ⁷ includes the value of the pilot-to-data tone energy ratio used to transmit the third symbols in a corresponding interval, such as the OFDM 123 symbol in Figure 9, between the OFDM symbols transmitted by an interval. The 'ThirdSymbolsPTDTPRX ⁷ field is only included when the' PilotToneToDataTonePowerRatioIncluded ⁷ field is set to Ί ⁷ and the 'InterlaceXIncluded ⁷ field is set to Ί ⁷ .

field 'FourthSymbolsPTDTPRX (Proportion of data tone energy to pilot tone for the four symbols transmitted in interlaced intervals X, for X = 0, 1, 2, or 3) ⁷ includes the value of the pilot-to-tone energy ratio data used for the transmission of the fourth symbols in a corresponding interval, such as the OFDM 124 symbol in Figure 9, between the OFDM symbols transmitted by an interval. The 'FourthSymbolsPTDTPRX ⁷ field is included

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only when the 'PilotToneToDataTonePowerRatioIncluded' field is set to '1' and the 'InterlaceXIncluded' field is set to '1'.

Figure 10 is a flowchart illustrating the operation of a transmitter in an HRPD system for a broadcast service according to another exemplary version of the present invention in which the transmitter uses different proportions of pilot-to-data energy for individual positions OFDM symbols. In an exemplary version of the present invention, the transmitter in an HRPD system for a broadcast service refers to a base station.

In step 10, the transmitter generates data tones from broadcast data to be transmitted, using a channel encoder 301, a channel interleaver 302 and a modulator 303. The transmitter inserts guard tones within the data tones in step 11, and inserts pilot tones within the data tones inserted in the guard tones.

The transmitter determines in step 13 whether a corresponding OFDM symbol is located at the first position in the range. If the OFDM symbol is the first OFDM symbol in the range, the transmitter allocates energy for pilot tones and data tones according to the energy ratio R_1 in step 14. Otherwise, the transmitter determines in step 15 whether the OFDM symbols are located in the second position of the range. If the OFDM symbol is the second OFDM symbol in the range, the transmitter allocates energy to pilot tones and data tones according to an energy ratio R_2 in step 16. Otherwise, the transmitter determines, in step 17, whether the symbols OFDM are located in the third position of the range. If the symbol

38/46 • ··· · ······ · · • · ··· ··· · · ···· * · «· · · • · · · · · · · ···· ·· · · · · · ··· · · ·····

OFDM is the third OFDM symbol of the range, the transmitter allocates energy to the pilot tones and data tones according to an energy ratio R_3 in step 18. Otherwise, as this indicates that the OFDM symbol is located in the last position of the range , the transmitter allocates energy to the pilot tones and data tones according to the energy ratio R_4 in step 19.

Thereafter, in step 20, the transmitter performs a different QPSK spread according to the BCMCS content identifier, using a QPSK 3 07 spreader. In step 21, the transmitter performs an IFFT process using the IFFT 3 08 unit, and inserts a CP inside the symbol processed by the IFFT using a CP 3 09 inserter, completing the OFDM signal. Thereafter, the transmitter performs an HRPD-compatible process using an HRPD 310-compatible processor in step 22, and transmits the completed OFDM signal in step 23.

With reference to Figure 11, a description will now be made of a process of restoring a broadcast signal at the receiver upon receipt of the OFDM signal generated through the operation of Figure 10.

Figure 11 is a flowchart illustrating the operation of a receiver in an HRPD system for a broadcast service according to another exemplary version of the present invention in which the receiver uses different proportions of pilot-to-data energy for individual positions OFDM symbols. In an exemplary version of the present invention, the receiver in an HRPD system for a broadcast service refers to a terminal.

In step 30, the receiver receives R_l, R_2, R_3 and R_4

39/46 from a base station or transmitter. When the failure to receive R_l, R_2, R_3 and R_4 fails, the receiver uses the initial values for R_1, R_2, R_3 and R_4. Upon receipt of a BCMCS interval, the receiver extracts the OFDM symbol from the BCMCS interval received in step 31, and performs the QPSK de-spreading on the OFDM symbol extracted in step 32, receiver determines, in step 33, whether the OFDM symbol is located in the first interval position. If the OFDM symbol is the first OFDM symbol of the interval, the receiver performs the channel estimation according to a pilot-to-data tone energy ratio R_1 in step 34. Otherwise, the receiver determines, in step 35, whether the OFDM symbol is located in the second position of the range. If the OFDM symbol is the second OFDM symbol in the range, the receiver estimates the channel according to a pilot-to-data tone energy ratio R_2 in step 36. Otherwise, the receiver determines, in step 37, whether the OFDM symbol is located in the third position of the range. If the OFDM symbol is the third OFDM symbol of the range, the receiver performs the channel estimation according to a pilot-paradigm energy ratio R_3 in step 38. Otherwise, this means that the OFDM symbol is located in the the interval position, the receiver performs the channel estimation according to a pilot-to-data tone energy ratio R_4 in step 39. In the channel estimation processes of steps 34, 36, 38 and 39, the receiver uses tones pilots located on adjacent OFDM symbols.

In step 40, the receiver extracts data tones from the

40/46 • * * · · ·· »···

estimated channel and demodulates the extracted data tones. In step 41, the receiver finally decodes the demodulated data tones within the broadcast signal transmitted from the transmitter.

As described above, the transmitter sets a different energy ratio according to the position of the OFDM symbols in an interval in the transmission of an OFDM signal. Upon receipt of the OFDM signal, the receiver can perform channel estimation on the OFDM signal according to the energy ratio, thus improving the channel estimation performance of the OFDM symbols.

Figure 12 is a block diagram illustrating the structure of a receiver to receive an OFDM signal that the transmitter transmitted after setting a different energy ratio depending on the position of the OFDM symbol, according to a version of the present invention. With reference to Figure 12, a description will now be made of a structure and operation of a receiver to receive an OFDM signal that the transmitter transmitted after setting a different energy ratio depending on the position of the OFDM symbol, according to a version of the present invention. .

receiver is compatible with HRPD technology. Therefore, an HRPD 71 compliant receiving processor receives the HRPD signal, extracts a partial signal mapped to data from the received HRPD signal, and determines whether the received data is OFDM data or CDM data. In the case of a broadcast service, the HRPD 71 compliant receiving processor can determine a transmission scheme for the received data by checking whether the MSB has a value of '1', which indicates the broadcast service.

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As described above, in the HRPD system, the receiver can receive a broadcast signal that the transmitter transmitted by OFDM in each interval, or receive a single signal or control signal that the transmitter transmitted by CDM in each interval. A description of a method for receiving the control signal transmitted by CDM in a receiver to detect the pilot-to-data energy ratio will first be described. Upon receipt of a control signal or an energy proportion signal from the HRPD system, the HRPD 71 compliant receiving processor outputs the received signal to an energy proportion message receiver 72. The energy proportion message receiver 72 extracts an energy proportion message from a CDM control signal, and outputs an energy proportion value selected from the extracted energy proportion message to a channel 73 estimation weight decision maker. Here, the term energy proportion refers to up to a pilot-designed energy proportion of tone.

The channel estimation weighting decision 73 determines a weighting for each individual channel, necessary for the channel estimation, using the energy proportion value, and issues the channel estimation weight determined for the channel estimator 78.

Next, a description of a method for receiving a transmitted OFDM signal at the receiver will be made. The transmitted OFDM signal is output to an OFDM 1200 processor. A data management process on the OFDM 1200 processor will now be described.

The OFDM 1200 processor provides the OFDM signal

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• · · · * · · • ··· · ····· received to a CP 74 remover to remove the CP from the received OFDM signal. The CP 74 remover removes the contaminated CP by the propagation delay and multivia delay of the received signal, and emits the signal with CP removed to a Fast Fourier Transform (FFT) processor 75. The FFT 75 processor converts the signal from entry into the time domain in a signal in the frequency domain, and output the signal in the frequency domain to the QPSK 7.6 spreader.

76 QPSK spreads the signal in the frequency domain and outputs the scattered signal by QPSK to a pilot tone extractor 77. The reason why the QPSK spreader 76 scatters the signal in the frequency domain by QPSK is because the transmitter has spread the PPSSK signal. transmission before transmission. The QPSK 76 scatter emits guard tones, pilot tones and data tones on a mixed basis as shown in Figure 3. The pilot tone extractor 77 extracts pilot tones from the scattered signal by QPSK, emits the extracted pilot tones to the channel estimator 78, and output the remaining tones to a data tone extractor 79. The data tone extractor 7 9 extracts only the tones mapped to data between the tones emitted from the pilot tone extractor 77, and outputs the extracted data tones to a demodulator 80.

The pilot tones extracted by the pilot tone extractor 77 are entered in the channel estimator 78. The channel estimator 78 estimates the channel using the channel estimation weight determined by the channel estimation weighting decision 73.

After channel estimation, the channel estimator 78

6?

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output an estimated channel value to demodulator 80. Demodulator 80 demodulates data tones using the estimated channel value, and outputs a demodulated signal to deinterleaver 81. Deinterleaver 81 deinterlaces the demodulated signal, and outputs the deinterlaced signal to decoder 82. Decoder 82 decodes the deinterlaced signal thereby restoring a transmitted signal, for example, the transmitted broadcast signal.

Figure 13 is a flow chart illustrating the process of receiving an OFDM signal at a receiver in an HRPD system according to a version of the present invention. With reference to Figure 13, a detailed description of a process of receiving an OFDM signal at a receiver in an HRPD system according to a version of the present invention will now be made.

Referring to Figure 13, the receiver receives an energy proportion message in step 51. The receiver receives the energy proportion message in different ways according to the method of transmission. Upon receipt of the energy proportion message, the receiver determines an estimated channel value using the energy proportion message receiver 72, a channel weight estimator for channel 73 and a channel estimator 78. In step 52, the receiver reads the DCPilotToDataRatio field from the received energy proportion message, and stores pilot-to-DC energy tone proportions. In this case, the receiver stores energy information for the pilot tones located on the outside of a range that transmits OFDM symbols and energy information for the pilot tones and data tones located on one side

44/46 • · · ··· · · * · ··· · · ♦ * · · ··· · ····· • · · · ·· · · ··· ··· ··· · · ·· ·· »« ·· «··· · • * · ···· * ····« inside the interval. Thereafter, the receiver determines in step 53 whether the MSB of an EBCMCSTransmissionFormat field in the received message is set to '1'. If the MSB is set to '1', the receiver proceeds to step 54. Otherwise, the receiver proceeds to step 55.

In step 55, the receiver determines whether the DualPDREnableForThisLogicalCh field value is set to Ί '.

If the DualPDREnableForThisLogicalCh field value is determined to be set to Ί ', the receiver proceeds to step 62. Otherwise, the receiver proceeds to step 61. In step 62, the receiver reads an ACPilotToDataRatioOuterSymbols field and an ACPilotToDataRatioInnerSymbols field regardless of order of intervals, and stores proportions of pilot tone energy to AC data in the inner OFDM symbols and the outer OFDM symbols. In step 61, the receiver reads an ACPilotToDataRatio field regardless of the order and position of the intervals, and stores the pilot-to-data AC energy proportions,

In step 54, the receiver determines whether a value in a DualPDREnabledForThisLogicalCh field is set to Ί '.

If it is determined that the DualPDREnabledForThisLogicalCh field value is set to Ί ', the receiver proceeds to step 64. Otherwise, the receiver proceeds to step 63.

In step 64, the receiver reads the ACPilotToDataRatioOuterSymbols1 field and the ACPilotToData RatioInnerSymbolsl field for the interval before a change in transmission format, and stores pilot-to-data AC energy proportions in the internal OFDM symbols and in the

45/46 • · · · ···· · ····· external OFDM symbols. In addition, the receiver reads the ACPilotToDataRatioOuterSymbols2 field and the ACPilotToData RatioInnerSymbols2 field for the interval after a change in the transmission format, and stores pilot-to-data AC energy proportions in the internal OFDM symbols and the external OFDM symbols.

In step 63, the receiver reads the ACPilotToDataRatiol field and the ACPilotToDataRatio2 field regardless of the positions of the OFDM symbols in the intervals, and stores pilot-tone energy proportions for AC data separately for the interval before a change in transmission format and in the interval after a change in the transmission format.

After step 61, 62, 63 or 64, the receiver stores pilot tone reception symbols in step 65. Thereafter, in step 66, the receiver determines the channel estimation weight depending on the pilot-tone energy proportions. for DC data and in the pilot tone-to-AC power ratio. In step 67, the receiver estimates the channel experienced by the data tones by combining and interpolating the pilot tone reception symbols using the channel estimation weight, and stores the estimated channel value. In step 68, the receiver restores the broadcast signal by demodulating and decoding the data tones using the estimated channel value.

As can be seen from the previous description, the BCMCS transmission device based on OFDM being compatible with HRPD technology fixes a different proportion of pilot-to-data tone energy according to the position of the OFDM symbols, thereby improving the

46/46 • · · · · · * ···· · · ***** ·· · ····· • · · · · · ♦ · · * ·· ··· · · * · «· · · ·· »···· · · · · • · · · · · · · «··· channel estimation performance for OFDM symbols located at the boundary of the interval, improving performance in channel estimation contributes to improving reception performance.

Although the invention has been shown and described with reference to a certain exemplary version of it, it will be understood by those skilled in the technology that various changes in form and details can be made in it without deviating from the spirit and scope of the invention as defined by the appended claims. For example, while exemplary versions of the present invention have been applied to a system where BCMCS technology supports the OFDM transmission scheme in compatibility with HRPD technology, the versions can also be applied to another broadcast system based on

OFDM.

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Claims (22)

1. Apparatus for transmitting a packet data symbol in a high speed mobile packet data (HRPD) communication system for a broadcast service, the apparatus comprising: a transmission processor for generating a modulated symbol by encoding, interlacing and modulating a physical layer packet to be transmitted, and arranging the modulated symbol in a data tone; a tone inserter to insert a guard tone and a pilot tone within the data tone; a tone energy allocator to establish a different pilot-to-data energy ratio for the interval position, in which the packet data symbol is included, and allocate energy according to the pilot tone energy proportion -for data; and a transmitter for transmitting the packet data symbol. 2. Apparatus according to claim 1, characterized in that the tone energy allocator allocates energy to the pilot tone and the data tone according to a first energy ratio if the packet data symbol is located on the outside the interval, and allocates energy to the pilot tone and data tone according to a second energy ratio if the packet data symbol is located on the inner side of the interval. 3, Apparatus, according to claim 1, characterized by the fact that the tone energy allocator establishes a different proportion of pilot-paraded tone energy according to the position of the interval, in 2/8 • · ♦ · · ♦ that the packet data symbol is included, and transmits the pilot-to-data tone energy ratio through a signal message. 4. Apparatus according to claim 3, characterized by the fact that the signaling message includes information on a pilot tone energy ratio for DC data. 5. Apparatus according to claim 3, characterized in that the signaling message comprises at least one of a field that indicates whether the pilot-to-data tone energy ratio is included, a field that includes the energy ratio pilot-to-data tone used for transmitting internal symbols between symbols transmitted in an interval, and the field that includes the proportion of pilot-to-data tone energy used for transmitting external symbols between symbols transmitted in a symbol . 6. Apparatus according to claim 3, characterized in that the signaling message comprises information in a pilot-to-data tone energy ratio to apply a different pilot-to-data tone energy ratio for each individual interlace during transmission of the packet data symbol. 7. Apparatus according to claim 3, characterized in that the signaling message comprises at least one of a field that indicates whether the proportion of pilot-to-data tone energy is included, fields each indicating whether the information to be be transmitted using each of the interlaced intervals 3/8 • * · ** »» · * · · · »« '· * · »* *» ·· »» ···· * «·« *> «*> • · * · * «· * ·» «*» »·« * · «· · • # *« · * * »·« · is included, fields each including a pilot-to-tone energy ratio data used for the transmission of interior symbols between symbols transmitted in an interval included in each interlace, and fields each including a pilot-to-data tone energy ratio used for the transmission of external symbols between the OFDM symbols transmitted in a range included in each interlace. 8. Apparatus according to claim 1, characterized in that the tone energy allocator applies a different pilot-to-data tone energy ratio for each individual interlacing during the transmission of the packet data symbol. 9. Method for transmitting a packet data symbol in a high speed mobile packet data (HRPD) communication system to a broadcast service, the method characterized by comprising the steps of: generate a modulated symbol when encoding, interlacing and modulating a physical layer packet to be transmitted, and arranging the modulated symbol in a data tone; insert a guard tone and a pilot tone within the data tone; establishing a different pilot-to-data energy proportion according to the position of the interval, in which the packet data symbol is included, and allocating energy according to the pilot-to-data energy proportion; and transmitting the packet data symbol. 10. Method according to claim 9, 4/8 • '* «Ο * · ··» ·· * · · »· * · · · ··· · · •••• laughs« 4 «« ·· »· · ··· tf ·· ······· ··· «» * · ···· «··« ·· characterized by the fact that the tone energy allocation step comprises the step of allocating energy to the pilot tone and the data tone of according to a first energy proportion if the packet data symbol is located outside the range, and allocate energy to the pilot tone and data tone according to a second energy proportion if the packet data symbol is located on the inner side of the range. 11. Method according to claim 9, characterized in that it further comprises the step of establishing a different pilot-to-data energy ratio according to the position of the interval, in which the packet data symbol is included, and transmitting the pilot tone-to-data energy ratio via a signaling message. 12. Method, according to claim 11, characterized by the fact that the signaling message includes information in a proportion of DC-pilot tone energy. 13. Method according to claim 11, characterized in that the signaling message comprises at least one of a field that indicates whether the pilot-to-data tone energy ratio is included, a field that includes an energy proportion pilot tone = for data used for the transmission of internal symbols between the symbols transmitted in an interval, and the field that includes a proportion of pilot tone energy for data used for the transmission of external symbols between the symbols transmitted in a symbol. 5/8 * · • «•« »* * ·· • • H· ··· • ··· • • ·· • • · ·· • · · ·· • • • «• · * «« « «• • ♦ · « • · · • · • • • · • • • · • ··· « • ··· ·· 14. Method according to claim 11, characterized in that the signaling message comprises information on the pilot-to-data tone energy ratio to apply a different pilot-to-data tone energy ratio for each individual interlace during transmission of the packet data symbol. 15. Method, according to claim 11, characterized by the fact that the signaling message comprises at least one of a field that indicates whether the proportion of pilot-to-data tone energy is included, fields each indicating whether the information to be be transmitted using each of the interlaced ranges is included, fields each including a pilot-to-data tone energy ratio used for the transmission of the interior symbols between the symbols transmitted in a range included in each interlaced, and fields each including a proportion of pilot-to-data tone energy used for the transmission of external symbols between the OFDM symbols transmitted in an interval included in each interlace. 16. Method according to claim 9, characterized in that a different pilot-to-data tone energy ratio is applied to each individual interlacing during the transmission of the packet data symbol. 17. Method for receiving a packet data symbol in a high-speed packet data (HRPD) communication system for a broadcast service, the method characterized by understanding the steps 6/8 of: when receiving information about the proportion of pilot-to-data energy determined according to the position of the packet data symbol, store the proportion of pilot-to-data energy according to the position of the symbol; if the received packet is an orthogonal frequency division (OFDM) multiplexing packet, extract a data symbol from the OFDM packet and scatter the extracted data symbol, thus extracting a data tone and a pilot tone; estimate the channel using a pilot-to-data energy ratio of the OFDM package; and restoring data from the data tone using the channel estimation information. 18. Method according to claim 17, characterized in that the channel estimation step comprises the step of estimating the channel according to a first energy proportion if the packet data symbol is located on the outside of the interval, and estimating the channel according to a second energy ratio if the packet data symbol is located on the inner side of the range. 19. Method, according to claim 17, characterized by the fact that the data restoration step comprises the steps of: demodulate the data tone using the estimated channel information; deinterlace the demodulated signal; and decode the deinterlaced signal. 7/8 20. Apparatus for receiving a packet data symbol in a mobile high-speed packet data (HRPD) communication system for a broadcast service, the apparatus comprising: a channel estimation unit to receive a control message, extract the pilot tone-to-data energy ratio according to the position of the packet data symbol, determine the channel estimation weight, and estimate the channel according to the proportion of pilot-to-data tone energy; an orthogonal frequency division multiplexing (OFDM) processor to divide the received OFDM symbol into a pilot tone and a data tone, supply the pilot tone to the channel estimation unit, and output the data tone; and a data restoration unit for restoring information transmitted from the data tone using the channel estimation information provided from the channel estimation unit. 21. Apparatus according to claim 20, characterized by the fact that the channel estimation unit comprises: an energy proportion message receiver for receiving the control message; a channel estimation weight decision maker to determine a channel estimation weight of the energy proportion message receiver output; and a channel estimator to receive the channel estimation weight and the pilot tone, and determine the estimated value of the channel according to the position and energy of the Ο 8/8 pilot tone. 22. Apparatus according to claim 20, characterized in that the data restoration unit comprises: a demodulator for demodulating the data tone using the estimated channel value provided from the channel estimation unit; a deinterleaver to deinterlace the demodulated signal; and a decoder to decode the deinterlaced signal. 1/14 σ> ο co ο Τ'ο CO ο> Ou ο Μ Ο CO ο Ο <C θ S _2 zc s ι Σ2 α 2: ο -2 α ~ CÜ q I <u; ε 2Ζ (Ο _ro 2 α τ-Η fe 2/14 C \] ô AND 3/14 4/14 * »· * ♦ - · ♦ ♦> · · * · • <ι *« - · · · · • * · * • * * * · ♦ • ♦ * «·« 5/14 # · - * * · • ν · »« · · • J · • · • · • · • 4 121 .1 ..... 122 t .. 123 l. 124 ....... í Symbol OFDM Pilot & MAC Symbol OFDM Symbol OFDM Pilot & MAC Symbol OFDM CDM interval BCMCS OFDM range CDM Interval ~ 1 -! - r 401 402 403