KR20020031026A - Apparatus and method for determining data rate of packet data and modulation/demodulation parameter adaptively in mobile communications system supporting voice and packet data services - Google Patents

Abstract

PURPOSE: An apparatus and method for determining the transmission rate of adaptive packet data and modulation and demodulation parameters in a mobile communication system for voice and packet data services is provided to simultaneously perform a voice conversation and the transmission of forward packet data with a maximum transmission rate by suitably changing the demodulation parameters of a channel in a terminal according to the number of usable orthogonal(Walsh) code and changing the modulation parameters of the channel in a base station. CONSTITUTION: A CIR(Carrier to Interference Ratio)-Rm(maximum transmission rate) mapping table(1109) stores a certain maximum transmission rate corresponding to a certain CIR. A mobile station data rate controller(1105) obtains the maximum transmission rate stored in the CIR-Rm mapping table(1109) corresponding to CIR measured through a pilot channel and adjusts a symbol repetition rate according to the obtained maximum transmission rate and orthogonal code information assigned to a base station.

Description

Apparatus and method for determining transmission rate and modulation / demodulation parameter of adaptive packet data in mobile communication system for voice and packet data service SERVICES}

The present invention relates to a mobile communication system supporting a multimedia service including voice and packet data services, and more particularly, to an apparatus and method for determining an efficient packet data transmission rate and modulation and demodulation scheme.

A typical mobile communication system, for example, a code division multiple access (CDMA) mobile communication system such as IS-2000, only supports voice services. However, as technology advances along with user demands, mobile communication systems tend to develop in the form of supporting data services. Mobile communication systems such as so-called High Data Rate (HDR) are systems that support only high-speed data services.

As such, the existing mobile communication system is considered to support only a voice service or only a data service. That is, although the mobile communication system needs to simultaneously service a voice service and a data service, the existing mobile communication system supports each service separately. Therefore, there is a demand for the implementation of a mobile communication system capable of supporting data services while supporting existing voice services.

Accordingly, an object of the present invention is to provide an apparatus and method for controlling a packet data rate of a mobile communication system for voice and packet data services.

Another object of the present invention is to provide an apparatus and method for determining the maximum data rate and modulation / demodulation parameter of packet data in consideration of the orthogonal code and the physical channel characteristics of a transport channel usable in a mobile communication system in which a voice user and a packet data user coexist. .

The present invention for achieving these objects proposes an apparatus for adaptively adjusting a parameter for demodulation in a terminal of a mobile communication system for voice and packet data services. The apparatus obtains an estimated maximum data rate corresponding to the received signal-to-noise ratio measured through a pilot channel, and calculates a symbol repetition rate according to the maximum data rate and orthogonal code information assigned to the base station. If the calculated symbol repetition rate is greater than a preset repetition rate, the symbol repetition rate is determined as a symbol repetition rate for demodulation, and when the symbol repetition rate is smaller than the set repetition rate, the number of slots forming a packet is increased or the number of symbols in the packet is increased. Decreases.

Is a diagram illustrating a forward link data traffic channel structure for a packet data service according to an embodiment of the present invention.

1B is a diagram illustrating a forward link data traffic MAC channel structure for a packet data service according to an embodiment of the present invention.

2 shows a configuration of a forward link transmitter for a data traffic channel according to an embodiment of the present invention.

3 illustrates a configuration of a forward link transmitter for a data traffic MAC channel according to an embodiment of the present invention.

4 illustrates a configuration of a forward link transmitter for a common power control channel (CPCCH) according to an embodiment of the present invention.

5 illustrates a configuration for orthogonal spreading and high frequency (RF) band frequency transition for a forward link channel according to an embodiment of the invention.

6 is a diagram showing the configuration of frequency down-converting, quadrature despreading, and channel estimation according to an embodiment of the present invention.

7 illustrates a configuration of a forward link receiver for a data traffic channel according to an embodiment of the present invention.

8 illustrates a configuration of a forward link receiver for a data traffic MAC channel according to an embodiment of the present invention.

9 illustrates a configuration of a forward link receiver for a common power control channel (CPCCH) according to an embodiment of the present invention.

10 is a diagram showing a relationship between orthogonal code distribution between a voice user and a packet data user and a signal-to-noise ratio (CIR) of a packet channel in a mobile communication system to which the present invention is applied.

11 illustrates a configuration of a forward link transmitter for a data traffic channel having a transmission rate and modulation parameter determination function according to an embodiment of the present invention.

12 illustrates a slot structure when a forward link transmitter transmits a packet at a transmission rate of 614.4 kbps according to an embodiment of the present invention.

13 illustrates a slot structure when a forward link transmitter transmits a packet at a transmission rate of 307.2 kbps according to an embodiment of the present invention.

14 is a diagram showing the configuration of a forward link receiver for a data traffic channel having a rate and demodulation parameter determination function according to an embodiment of the present invention.

15 illustrates a channel structure in which a reverse link transmitter transmits rate control (DRC) information and sector indicator information according to an embodiment of the present invention.

16 is a diagram showing the configuration of an apparatus for determining a rate and modulation / demodulation parameter according to an embodiment of the present invention.

FIG. 17 illustrates operation timing between a forward Walsh indicator channel, a forward pilot channel, a forward packet data channel, and a reverse DRC channel during a transmission rate and modulation / demodulation parameter determination operation according to an embodiment of the present invention. FIG.

18 is a flowchart illustrating a processing flow of a transmission rate and demodulation parameter determination operation by a DRC controller included in a terminal according to an embodiment of the present invention.

19 is a flowchart showing a processing flow of a rate and modulation parameter determination operation by a DRC controller included in a base station according to an embodiment of the present invention.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First of all, the present invention relates to a forward link of a mobile communication system capable of supporting a multimedia service including voice service and data service using 1x bandwidth. The transmitter, channel, and receiver structure for supporting the voice service remains the same as the transmitter, channel, and receiver structure of the existing 1x system, respectively. Here, 1x bandwidth refers to a frequency bandwidth of 1.25MHz used in the existing IS-95 series North American synchronous system, and 1x system refers to a system supporting 1x bandwidth. The data service may be broadly classified into a circuit mode operation and a packet mode operation according to the type of circuit connection for the service. The data service may be various video services such as a video conference, an internet service, or the like. The dedicated line data service uses the structure of the transmitter, channel, and receiver of the existing 1x system. Therefore, in the following invention, a transmitter, channel, and receiver structure for a packet data service will be described.

First, a summary of channels required for packet data service in a forward link of a mobile communication system according to an embodiment of the present invention is shown in Table 1 below.

Channels for Forward Link Packet-Based Data Services channel Usage Remarks ForwardPilot Channel Spread to Walsh code 0 and code multiplexed with other forward channels, the pilot symbols provided through the pilot channel are used as phase and amplitude reference values for synchronous demodulation and can be used as a means of receiving CIR measurement for rate control. . Same as the IS-95 pilot channel. Data Traffic Channel Preamble Subchannel It is transmitted by being multiplexed with the data traffic subchannel and time, and used for the purpose of designating a corresponding terminal for a data packet transmitted by a base station. Data Traffic Channel Data Traffic Subchannel The channel is time-multiplexed with the preamble subchannel to actually transmit the data payload. Data Traffic Channel PowerFractionInformationChannel A channel that transmits the ratio of the channel power allocated to the data traffic channel to the channel power of the forward pilot channel in a decibel or linear scale, and is determined from the received channel power measured from the pilot channel to 16QAM. Information for converting the amplitude reference value and the received CIR is provided. Data TrafficMAC Channel Walsh Space Indication Subchannel A channel for transmitting Walsh spatial information of a base station that can be allocated to a data traffic subchannel through dynamic Walsh allocation. Data TrafficMAC Channel Reverse Activity Indication Subchannel Broadcast channel for controlling the traffic load of the reverse link. Data TrafficMAC Channel

Referring to Table 1, channels for a forward link packet data service according to an embodiment of the present invention are classified into a pilot channel, a data traffic channel, and a data traffic MAC. Control) Channel is divided. The data traffic channel includes a preamble subchannel and a packet data traffic subchannel. The data traffic MAC channel is composed of a data channel power fraction information subchannel, a Walsh Space Indication Subchannel, and a Reverse Activity Indication Subchannel. The pilot channel refers to a forward common pilot channel of the IS-95. The pilot channel is code multiplexed with all other forward channels, and a pilot symbol provided through the pilot channel is used as a phase and amplitude reference value for synchronous demodulation. Along with the channel power ratio information channel, it is used as the target of CIR measurement for data rate control and amplitude reference value for 16QAM demodulation. The preamble subchannel is multiplexed with the data traffic subchannel and transmitted, and is used for the purpose of designating a corresponding terminal for a data packet transmitted by a base station. The data traffic subchannel is a channel multiplexed with the preamble subchannel so that the payload is actually transmitted. The data channel power ratio information channel is a channel for transmitting the ratio of the channel power of the data traffic subchannel to the power amount of the pilot channel. The data channel power ratio information channel becomes an I-ch component of the data traffic MAC channel. The Walsh space indication subchannel is a channel for transmitting Walsh space information of a base station that can be allocated to a data traffic subchannel through dynamic Walsh allocation. The Walsh spatial indication subchannel is multiplexed with the backward active indication subchannel to become the Q-ch component of the data traffic MAC channel. The reverse active indication subchannel is a broadcast channel for controlling the traffic load of the reverse link, and is multiplexed with the Walsh space indication subchannel to become a Q-ch component of the data traffic MAC channel.

In addition to the channels described in Table 1, a channel for a forward link packet data service according to an embodiment of the present invention is common for power control of a physical channel for a data service that operates in a dedicated line over a reverse link. There is a common power control channel (hereinafter referred to as "CPCCH").

1A illustrates a structure of a forward link data traffic channel (DTSCH) for a packet data service according to an embodiment of the present invention, and FIG. 1B illustrates a forward link data traffic MAC channel for a packet data service according to an embodiment of the present invention. Figure showing the structure. 1A and 1B, a minimum transmission unit of a physical layer for packet data service is a slot configured of 1,536 chips, which has a duration of 1.25 msec. In the case of an idle slot in which no data payload exists, the DTSCH is gated off to reduce interference to a service connected to a dedicated line and adjacent base station signals.

Referring to FIG. 1B, a data traffic MAC channel (TMMACCH) includes a first channel (I-ch) and a second channel (Quadrature Phase Channel (Q-ch)). The first channel I-ch is used as a data channel power ratio information channel (PFICH). The second channel Q-ch is used as a Walsh Space Indication Subchannel (WSISCH) and a Reverse Activity Indication Subchannel (RAISCH). During one slot, the WSISCH and RAISCH occupy 1,280 chips and 256 chips, respectively, and these channels are multiplexed to form a second channel Q-ch of the DTMACCH.

Meanwhile, a preamble subchannel (PSCH) not shown in FIGS. 1A and 1B is time-multiplexed with the DTSCH and transmitted through the DTCH. Since the PSCH is used for the purpose of designating a corresponding terminal for a data packet transmitted by a base station, the PSCH must exist in the first slot of the DTCH for transmission of a physical layer packet. The preamble symbol may have only a value of '0'.

2 is a diagram illustrating a configuration of a forward link transmitter for a data traffic channel according to an embodiment of the present invention. The forward link transmitter for the data traffic channel is characterized by time division multiplexing (TDM) the preamble subchannel (PSCH) signal and the data traffic subchannel (DTSCH) signal.

Referring to FIG. 2, a preamble symbol having a value of '0' is input to a signal point mapper 201 and mapped to '+1'. The output symbol of the signal point mapper 201 is input to a Walsh spreader 202, and a specific 64-ary biorthogonal Walsh code (or index) corresponding to a user's unique MAC identifier (ID) (or index). Or sequence). The Walsh spreader 202 outputs a sequence of a first channel and a sequence of a second channel. The output sequence of the Walsh spreader 202 is input to a sequence repeater 203 and subjected to sequence repetition according to a transmission rate. The sequence repeater 203 allows the output sequence of the Walsh spreader 202 to repeat the sequence up to 16 times according to the transmission rate. Therefore, the PSCH included in one slot of the DTCH may last from 64 chips up to 1,024 chips depending on the transmission rate. The output (I, Q) sequence of the sequence repeater 203 is input to a time division multiplexer 230 and multiplexed with the DTSCH.

In the data traffic channel DTSCH of FIG. 2, a bit sequence to be transmitted is channel coded, input to a scrambler 211, and scrambling. The output sequence of the scrambler 211 is input to a channel interleaver 212 and interleaved. In this case, the size of the channel interleaver 212 is also applied differently according to the size of the physical layer packet. The output sequence of the channel interleaver 212 is input to an M-ary symbol modulator 213 and mapped to an M-ary symbol. The M-ary symbol modulator 213 operates as a quadrature phase shift keying (QPSK), a phase shift keying (8-PSK), or a quadrature amplitude modulation (16-QAM) modulator according to a transmission rate, and a physical layer packet unit whose transmission rate can be changed. The modulation method can also be changed. The (I, Q) sequence of M-ary symbols output from the M-ary symbol modulator 213 is input to a sequence repeater / symbol puncturer 214, and the sequence repetition / symbol puncture is performed according to a transmission rate. The (I, Q) sequence of M-ary symbols output from the sequence repetition / symbol puncturer 214 is input to a symbol demultiplexer 215. The (I, Q) sequences of the M-ary symbols input to the symbol demultiplexer 215 are demultiplexed into N Walsh code channels available for DTSCH and output. The number N of Walsh codes used for the DTSCH is variable, and information about this is broadcast through the WSISCH, and the terminal determines the transmission rate of the base station in consideration of this information and requests the base station. Accordingly, the UE can know the allocation status of the Walsh code used for the currently received DTSCH. Output (I, Q) symbols of the symbol demultiplexer 215, which are demultiplexed into N Walsh code channels and output, are input to the Walsh spreader 216 and are spread by a specific Walsh code for each channel. The output (I, Q) sequences of the Walsh spreader 216 are input to a Walsh Channel Gain Controller 217 and are output after gain control. The N output (I, Q) sequences output from the Walsh channel gain controller 217 are input to the Walsh Chip Level Summer 218, added in units of chips, and then output. The (I, Q) chip sequence output from the Walsh chip summer 218 is input to the time division multiplexer 230 and multiplexed with the PSCH.

The time division multiplexer 230 multiplexes the I-channel signal of the DTSCH and the I-channel signal of the PSCH and outputs the A-channel signal. The I channel signal of the DTSCH is an I sequence from the Walsh chip summer 218, and the I channel signal of the PSCH is an output signal of the gain controller 203. The time division multiplexer 230 multiplexes the Q-channel signal of the DTSCH and the Q-channel signal of the PSCH and outputs the B-channel signal. The Q channel signal of the DTSCH is a Q sequence from the Walsh chip summer 218. When the PSCH is transmitted on the I channel, 0 is input as the Q channel signal of the PSCH.

3 is a diagram illustrating a configuration of a forward link transmitter for a data traffic MAC channel according to an embodiment of the present invention.

In FIG. 3, a PFICH (data channel power ratio information channel) consisting of reference numerals 301 to 304 is a DTMACCH for transmitting a ratio of channel power of a data traffic subchannel to power of a pilot channel in a value of 7 bits per slot. Is the subchannel of. The 7-bit information is input to a channel encoder 301. The channel encoder 301 may use a block code or a convolution code for channel coding of the 7 bit information. As an example, a (24,7) block code may be used as the block code of the channel encoder 301. The output symbols of the channel encoder 301 are input to the signal point mapper 302. The output symbol '0' of the channel encoder 301 is mapped to '+1' by the signal point mapper 302, and the output symbol '1' of the channel encoder 301 is mapped to '-1' by the signal point mapper 302. And output. The output symbols of the signal point mapper 302 are input to the Walsh spreader 303 and spread by a particular 64-ary Walsh code assigned to the DTMACCH. The chip sequence output from the Walsh spreader 303 is input to the gain controller 304 and gain controlled after being output. The output of the gain controller 304 becomes a signal component of I-ch, which is the first channel of the DTMACCH.

RAISCH of reference numbers 311 to 314 is a broadcasting channel for adjusting the traffic load of the reverse link, and is a subchannel of the DTMACCH. Information for adjusting the traffic load of the reverse link is provided by 1 bit for each slot. The 1-bit reverse activity indication (RAI) information is input to a symbol repeater 311, and the symbol repeater 311 repeatedly outputs an input symbol four times. The output symbols of the symbol repeater 311 are input to a signal point mapper 312. The symbol '0' among the output symbols of the symbol repeater 311 is mapped to '+1' by the signal point mapper 312, and the symbol '1' is mapped to '-1' by the signal point mapper 312. Is output. The output symbols of the signal point mapper 312 are input to a Walsh spreader 313 and spread by a particular 64-ary Walsh code assigned to the DTMACCH. The chip sequence output from the Walsh spreader 313 is input to the gain controller 314 and gain controlled after being output. The output of the gain controller 314 is input to the time division multiplexer 330 and multiplexed with the WSISCH signal, which becomes a Q-ch signal component that is the second channel of the DTMACCH.

WSISCH, which is formed by reference numerals 321 to 324, is a channel for transmitting information about a base station Walsh space that can be allocated to a DTSCH through dynamic Walsh allocation, which is a subchannel of DTMACCH. For example, if a Walsh code other than the Walsh code assigned to the dedicated circuit physical channel is used in the DTSCH at a spreading factor of 32, up to 28 32-ary Walsh codes may be allowed in the DTSCH. have. As another example, when a Walsh code other than the Walsh code allocated to the dedicated circuit physical channel is used in the DTSCH at the spreading index level of 64, up to 56 64-ary Walsh codes may be used for the DTSCH. As another example, when a Walsh code other than the Walsh code allocated to the dedicated line physical channel is used in the DTSCH at the spreading index level, a maximum of 112 128-ary Walsh codes may be used for the DTSCH. Hereinafter, an example in which a maximum of 28 32-ary Walsh codes are used in the DTSCH using the Walsh codes other than the Walsh codes allocated to the dedicated line physical channel at the spreading index level 32 will be described. If the Walsh code used for the PICH is defined to be used in the DTSCH, information about the Walsh space may be transmitted as 27 bits by using flag bits for each of the remaining 27 32-ary Walsh codes. If the flag bits for 27 Walsh codes are specified to be transmitted by dividing 3 bits per slot over 9 slots, information about the Walsh space is provided by 3 bits per slot.

Information about the 3-bit Walsh space is input to the channel encoder 321. The channel encoder 321 may use a block code or a convolution code for channel encoding of 3-bit information about a Walsh space. For example, a (20,3) block code or a (180,27) block code may be used as a block code of the channel encoder 321 for channel encoding of 3-bit information about Walsh space. The output symbols of the channel encoder 321 are input to the signal point mapper 322. The symbol '0' among the output symbols of the channel encoder 321 is mapped to '+1' by the signal point mapper 322, and the symbol '1' among the output symbols of the channel encoder 321 is the signal point mapper 322. Is mapped to '-1' and output. The output symbols of the signal point mapper 322 are input to a Walsh spreader 323 and spread by a particular 64-ary Walsh code assigned to the DTMACCH. The chip sequence output from the Walsh spreader 323 is input to the gain controller 324 and gain controlled after being output. The output of the gain controller 324 is input to the time division multiplexer 330 and multiplexed with the RAICH, and this multiplexed signal becomes a component of the Q-ch signal, which is the second channel of the DTMACCH.

4 is a diagram illustrating a configuration of a forward link transmitter for a common power control channel (CPCCH) according to an embodiment of the present invention. This transmitter is the transmitter of the forward link to the CPCCH for power control of the physical channel for data services operating in a dedicated circuit on the reverse link.

Through the CPCCH configured as shown in FIG. 4, power for the reverse physical channel may be controlled in units of slots. In this case, the CPCCH is divided into a first channel I-ch and a second channel Q-ch, and transmits power control commands for eight reverse physical channels through the first channel I-ch and the second channel Q-ch. Can be. Power control command bits for eight reverse physical channels are multiplexed on the first channel I-ch of the CPCCH, and power control command bits for eight reverse physical channels are multiplexed on the second channel I-ch. Different initial offsets are given for each of the eight reverse physical channels for multiplexing. Initial offsets 0-7 are given for the first channel I-ch, and initial offsets 8-15 are given for the second channel Q-ch.

The long code generator 401 inputs a long code mask for the CPCCH and generates a long code at a clock of 1.2288 MHz. The output of the long code generator 401 is input to a decimator 402, and the decimator 402 decimates an input symbol and outputs the decimator 402. For example, the decimator 402 may output one symbol for every 192 input symbols. At this time, the output signal of the decimator 402 is driven with a clock 192 times lower than the input signal. The output symbol of the decimator 402 is input to a relative offset calculator 403. The relative offset calculator 403 calculates and outputs a relative offset from the symbol output from the decimator 402.

The multiplexer 411 multiplexes the power control command bits for the eight reverse physical channels using the initial offsets 0-7 for the eight reverse physical channels and the output of the relative offset calculator 403. The multiplexer 411 may output a signal having a data rate of 6400bps. The output symbols of the multiplexer 411 are input to a symbol repeater 412, and the symbol repeater 412 repeats an input symbol three times. The output symbols from the symbol repeater 412 may have 19200 bps. The output symbols of the symbol repeater 412 are input to a signal point mapper 413. The signal point mapper 413 maps and outputs a symbol '0' to '+1' and a symbol '1' to '-1' among the input symbols. In this case, when there is no input symbol, the signal point mapper 413 outputs '0'. The output symbols of the signal point mapper 413 are input to a gain controller 414 and gain controlled. The output symbols of the gain controller 414 are input to a Walsh spreader 415 and spread by a particular 64-ary Walsh code assigned to the CPCCH. The signal output from the Walsh spreader 415 is an I-ch signal, which is the first channel of the CPCCH, and is power control command bits for eight reverse physical channels.

The multiplexer 421 multiplexes the power control command bits for the eight reverse physical channels using the initial offsets 8-15 for the eight reverse physical channels and the output of the relative offset calculator 403. The multiplexer 421 may output a signal having a data rate of 6400bps. The output symbols of the multiplexer 421 are input to a symbol repeater 422, and the symbol repeater 422 repeats the input symbol three times. Output symbols from the symbol repeater 422 may have 19200 bps. The output symbols of the symbol repeater 422 are input to a signal point mapper 423. The signal point mapper 423 maps the symbol '0' to '+1' and the symbol '1' to '-1' among the input symbols. In this case, when there is no input symbol, the signal point mapper 423 outputs '0'. The output symbols of the signal point mapper 423 are input to a gain controller 424 for gain control. The output symbols of the gain controller 424 are input to a Walsh spreader 425 and spread by a particular 64-ary Walsh code assigned to the CPCCH. The signal output from the Walsh spreader 425 is a Q-ch signal, which is a second channel of the CPCCH, and power control command bits for eight reverse physical channels and eight reverse physical channels that are power controlled through the I-ch.

5 is a diagram illustrating a configuration for orthogonal spreading and radio frequency (RF) band frequency transition for a forward link channel according to an embodiment of the present invention. This figure shows an operation of orthogonally spreading various channel signals of the forward link as shown in FIGS. 2 to 4 and transmitting them as a signal suitable for transmission to a terminal by frequency shifting to a signal of an RF band.

Referring to FIG. 5, the first summer 501 is a signal component of I-ch which is a first channel of DTCH, a signal component of I-ch which is a first channel of DTMACCH, and I-ch which is a first channel of CPCCH. The signal components are summed and output. The forward pilot channel (F-PICH) required by the IS-95 standard is spread to Walsh code '0' and added to the input of the summer 501 in a state in which a constant channel power is multiplied. The signal component of I-ch, which is the first channel of the DTCH, is the A output of the multiplexer 230 of FIG. 2, and the signal component of I-ch, which is the first channel of the DTMACCH, is the C output of the gain controller 304 of FIG. The signal component of I-ch, the first channel of the CPCCH, is the E output of Walsh spreader 415 in FIG. The first summer 501 adds and outputs the input signals of the first channel in units of chips. The second summer 502 sums the signal component of Q-ch, which is the second channel of the DTCH, the signal component of Q-ch, which is the second channel of the DTMACCH, and outputs the signal component of Q-ch, which is the second channel of the CPCCH. do. The signal component of the Q-ch which is the second channel of the DTCH is the B output of the multiplexer 230 of FIG. 2, and the signal component of the Q-ch which is the second channel of the DTMACCH is the D output of the multiplexer 330 of FIG. 3, and the CPCCH The signal component of Q-ch, which is the second channel of, is the F output of Walsh spreader 425 of FIG. The second summer 502 adds and outputs the input signals of the second channel in units of chips.

Quadrature spreader 510 uses a spreading sequence consisting of a first channel (I-ch) spreading sequence and a second channel (Q-ch) spreading sequence to a first summer 501 and a second summer 502. After complex spreading (or complex multiplying) the input signal, the first channel I-ch signal and the second channel Q-ch signal are output. The first channel I-ch signal from the quadrature spreader 510 is inputted to the low pass filter 521 to be low pass filtered. The second channel Q-ch signal from the quadrature spreader 510 is inputted to the low pass filter 522 to be low pass filtered. The output of the low pass filter 521 is input to a frequency shifter 531 to receive a first frequency. Transition to the RF band by the product of and the output of the low pass filter 522 is input to the frequency shifter 532 to the second frequency Transition to RF band by multiplication with Summer 540 sums the output signal of frequency shifter 531 and the output signal of frequency shifter 532. The sum signal by the summer 540 is radiated through an antenna (not shown).

6 is a diagram illustrating the configuration of frequency down-converting, quadrature despreading, and channel estimation according to an embodiment of the present invention. First, an RF forward signal transmitted from a forward link transmitter, i.e., a base station, is input to a receiver of a forward link receiver, and the received signals are input to mixers 601 and 602, respectively. The mixer 601 inputs the received signal to a carrier wave And down-convert the received frequency to convert the received frequency into a baseband signal and output it to a baseband filter 603. The baseband filter 603 receives the signal output from the mixer 601 and filters the baseband filter, and outputs the filtered signal to a quadrature despreader 605. The despreader 605 inputs the signal output from the baseband filter 603 and despreads the quadrature to separate the signals of other base stations and signals of other paths, and outputs them as I-channel components.

In addition, the mixer 602 carriers the received received signal. And convert the received frequency to down-convert the received frequency to convert it to a baseband signal and output it to the baseband filter 604. The baseband filter 604 inputs the signal output from the mixer 602 to filter the baseband and outputs the filtered signal to the quadrature despreader 605. The despreader 605 inputs the signal output from the baseband filter 604 and despreads the quadrature to separate the signals of other base stations and signals of other paths and outputs the Q-channel components. The I-channel component and the Q-channel component output from the despreader 605 are input to a channel estimator 606 to perform channel estimation. As a result, since the input signal of the channel estimator 606 is a signal multiplied by a '0' Walsh code, it is a channel estimation using a forward common pilot channel.

FIG. 7 illustrates a configuration of a forward link receiver for a data traffic channel according to an embodiment of the present invention. As illustrated in FIG. 6, a data traffic subchannel in a quadrature despreading signal, A receiver configuration for demodulating a preamble subchannel is shown.

As illustrated in FIG. 7, the signal input to the demultiplexer 701 is an I-channel component and a Q-channel component which are output signals of the quadrature despreader 605 described with reference to FIG. 6. 6 and 7 represent I-channel components and Q-channel components, which are output signals of the despreader 605, respectively. The demultiplexer 701 demultiplexes a signal of a data traffic subchannel and a signal of a preamble subchannel, which are multiplexed in time. In this case, the structure between the data traffic subchannel and the preamble subchannel is a structure in which the preamble subchannel is transmitted first and then the data traffic subchannel.

First, a demodulation process for the preamble subchannel will be described. First, the preamble subchannel separated by the demultiplexer 701 has a length different according to a data rate of a corresponding forward signal and is a specific 64-ary bidirectional corresponding to a user's unique MAC ID to receive the forward signal. Spread by a biorthogonal Walsh code and transmitted to I Ch or Q Ch according to a user's unique MAC ID to be received. In order to recover the preamble subchannel signal, the preamble subchannel signal separated by the demultiplexer 701 is output to a Walsh despreader 702. The Walsh despreader 702 inputs the preamble subchannel signal output from the demultiplexer 701 and despreads it into a 64-ary biorthogonal Walsh code determined according to a user's unique MAC ID to compensate for the channel compensation. Output to 703 The channel compensator 703 inputs the signal output from the Walsh despreader 702, performs channel compensation using the channel information estimated in FIG. 6, and then outputs the signal to the symbol combiner 704. Here, the estimated channel information denotes an output signal of the channel estimator 606, that is, an I-channel component and a Q-channel component, as described with reference to FIG. 6, and the I of the channel estimator 606 in FIGS. 6 and 7. The channel component is shown by ⓤ and the Q-channel component by ⓥ. In this way, the channel compensator 703 combines only the I channel component or Q channel component of the input signal according to the MAC index according to the user's MAC ID in the symbol combiner 704 to the user detector 705. Output The user separator 705 inputs a signal output from the symbol combiner 704 to determine whether the received forward signal is for a corresponding user.

Second, a demodulation process for the data traffic subchannel will be described. The remaining section except for the preamble subchannel in the demultiplexer 701 is a section including a data traffic subchannel, and the demultiplexer 701 separates the data traffic subchannel signal signal in the section. Output to Walsh despreader 706. The Walsh despreader 706 inputs the data traffic subchannel signal output from the demultiplexer 701, performs despreading with a plurality of Walsh codes assigned to the data traffic subchannel signal, and outputs the despreader to the channel compensator 707. Here, the signal output from the Walsh despreader 706 is output as a parallel signal corresponding to the number of Walsh codes allocated to the data traffic subchannel. The signal output from the despreader 706 is input to a channel compensator 707, and the channel compensator 707 performs channel compensation using the channel information estimated from the despreader 706 by using the channel information estimated from FIG. Output to converter 708. Here, the estimated channel information denotes an output signal of the channel estimator 606, that is, an I-channel component and a Q-channel component, as described with reference to FIG. 6, and the I of the channel estimator 606 in FIGS. 6 and 7. The channel component is shown by ⓤ and the Q-channel component by ⓥ. The parallel / serial converter 708 inputs the signal output from the channel compensator 707 to serially convert parallel signals and outputs the serial signal to a symbol combining / insertion 709. The symbol combiner / insertor 709 inputs a serial signal output from the parallel / serial converter 708 to perform combination or insertion of symbols according to repetition and puncturing of the transmitter, that is, the base station, thereby performing QPSK / 8PSK. / 16QAM demodulator 710 to output. The QPSK / 8PSK / 16QAM demodulator 710 inputs the signal output from the symbol combiner / insertor 709 to perform QPSK / 8PSK / 16QAM demodulation and then outputs the deinterleaver 711. The deinterleaver 711 performs deinterleaving, which is an inverse process to an interleaving process performed by an interleaver of the transmitter, and then outputs the deinterleaved signal to a turbo decoder 712. The turbo decoder 712 inputs the signal output from the deinterleaver 711, turbo decodes the channel, and extracts information bits.

8 is a diagram illustrating a configuration of a forward link receiver for a data traffic MAC channel according to an embodiment of the present invention. First, the I channel of the data traffic medium access control (MAC) channel is used as a Pilot Fraction Information Channel (PFICH), and the Q channel is a Walsh Space Indication Subchannel and a backward activity. Used as Reverse Activity Indication Subchannel. During one slot, the Walsh Space Indication Subchannel and the Reverse Activity Indication Subchannel occupy 1,280 and 256 chip intervals, respectively, and are time-division multiplexed to provide data traffic MAC (Medium Access Control). ) Share channels.

A signal demodulation process for a data traffic MAC (Medium Access Control) channel received by the receiver will be described with reference to FIG. 8. Here, the I channel input of the data traffic MAC channel, ie, PFICH, is the I-output channel of the Quadrature Despreader 605 of FIG. 6, and the Q channel input, that is, the Walsh space indicating subchannel and the reverse activity indicating channel, is the quadrature despreader of FIG. 6. 605 Q-outputs. The received data traffic MAC channel is input to a Walsh despreader 801, and the Walsh despreader 801 despreads the input data traffic MAC channel with a Walsh code assigned to the PFICH. Output to compensator 802. The channel compensator 802 inputs the signal output from the Walsh despreader 801 to perform channel compensation using the channel information estimated in FIG. 6, and then demodulates the I channel component and the Q channel component of the channel compensated signal, respectively. Output to 803 and 804. Here, the estimated channel information indicates an output signal of the channel estimator 606, i.e., an I-channel component and a Q-channel component, as described in FIG. 6, and the channel estimator in FIGS. 6, 7, and 8. The I-channel component of 606 is shown as ⓤ and the Q-channel component is shown as ⓥ. The demodulator 803 BPSK demodulates the I channel component output from the channel compensator 802 and outputs the demodulated signal to the block decoder 806. Here, the I channel signal demodulated by the demodulator 803 is a signal of PFICH. The block decoder 806 receives the I channel signal output from the demodulator 803 to block decode and restore the PFICH information.

Meanwhile, the Q channel signal among the channel compensated signals in the channel compensator 802 is output to the demodulator 804. The demodulator 804 inputs the Q channel signal output from the channel compensator 802, BPSK demodulates it, and outputs the demodulated signal to the demultiplexer 805. The demultiplexer 805 inputs and demultiplexes the signal output from the demodulator 804 to separate the reverse activity indicating subchannel signal and the Walsh space indicating subchannel signal. The backward activity indicating subchannel signal among the signals separated by the demultiplexer 805 is output to the block decoder 807, and the Walsh space indicating subchannel signal is output to the block decoder 808. The block decoder 807 recovers the backward activity indication channel information by inputting and block decoding the reverse activity indication subchannel signal input from the demultiplexer 805. The block decoder 808 recovers the Walsh spatial indication subchannel information by inputting and decoding the Walsh spatial indication subchannel output from the demultiplexer 805.

FIG. 9 is a diagram illustrating a configuration of a forward link receiver for a common power control channel (CPCCH) according to an embodiment of the present invention. In particular, FIG. 9 illustrates a physical channel for a data service operating in a dedicated circuit in a reverse link. FIG. Is a diagram illustrating a structure of a receiver for restoring Common Power Control Channel (CPCCH) information for power control.

First, the received signal is converted into a baseband signal, and the I-channel signal of the baseband signal is expressed as y, and the Q-channel signal is represented by ⓨ (see I & Q output signal 605 in FIG. 6). The baseband signal is input to a Walsh despreader 901, and the Walsh despreader 901 despreads the input baseband signal into a Walsh code assigned to the common pilot channel (CPCCH) to channel compensator 902. Output The channel compensator 902 inputs the signal output from the Walsh despreader 901 to perform channel compensation using the channel information estimated in FIG. 6, and then outputs the channel compensated signal to the RPCB extractor 903. Here, the estimated channel information indicates an output signal of the channel estimator 606, that is, an I-channel component and a Q-channel component, as described with reference to FIG. 6, and the I of the channel estimator 606 shown in FIGS. The channel component is shown by ⓤ and the Q-channel component by ⓥ.

The RPCB extractor 903 inputs a signal output from the channel compensator 902, extracts a reverse power control bit (RPCB), and outputs the reverse power control bit (RPCB) to the demodulator 904. In detail, first, a reverse power control bit (RPCB) to be used in a specific terminal is in a unique position among the signals that have been despread and subjected to channel compensation. This position is determined by an initial offset allocated to a specific terminal and a relative offset determined by a long code for CPCCH every 1.25 msec. Then, the RPCB extractor 903 extracts the RPCB distributed in the I channel or Q channel of the received signal by using the long code generated by the long code generator and the initial offset value assigned to the terminal every 1.25 msec. The signal extracted by the RPCB extractor 903 is BPSK demodulated by the demodulator 904 and then output to the block decoder 905. The block decoder 905 inputs the signal output from the demodulator 904 to perform block decoding, and as a result, restores the reverse power control bit information.

On the other hand, the forward data traffic channel (packet data channel) as described above does not continue the transmission time on the wireless channel in time, it can be shared by multiple packet data users at the same time. On the other hand, when circuit data (voice and data) users (hereinafter referred to as " voice users ") coexist, channel assignment of the voice user is performed independently of the channel occupancy time of the packet user. Although the transmission rate of the packet data on the radio link is physically limited by the carrier channel to noise ratio (CIR) of the packet channel, the orthogonal code assigned to the packet user due to the nature of the orthogonal code is assigned to the currently connected voice user. It must be different from the code. Therefore, the available transmission rate can only be limited again according to the amount of orthogonal codes available for packet transmission. Therefore, the maximum transmission rate of packet data should be determined by considering the orthogonal codes available in the mobile communication system where the voice user and the packet user coexist and the physical channel characteristics of the transport channel. For reference, in the current CDMA mobile communication system, all users access the system by code division multiplexing, and the orthogonal code allocation period for the packet channel and the orthogonal code allocation period for the voice channel are used the same. have. The principle of the present invention for determining efficiency by determining the maximum transmission rate of packet data in consideration of both the available orthogonal code and the physical channel characteristics of the transport channel will be described with reference to FIG.

FIG. 10 is a diagram illustrating a relationship between an orthogonal code distribution between a voice user and a packet data user and a receive-to-interference ratio (CIR) of a packet channel in a mobile communication system to which the present invention is applied. That is, FIG. 10 is a diagram illustrating a relationship between an orthogonal code assigned to a packet user accessing the forward direction simultaneously in time division and a voice user accessing the forward connection in the code division method, and a received CIR of the packet channel measured by the terminal. Since the Walsh code may be used as the orthogonal code, the Walsh code is used instead of the orthogonal code.

Referring to FIG. 10, packet data is transmitted in a short time period due to its characteristics, and several packet users access the base station by time division. Unlike this, a voice user accesses a base station independently of a packet user at a frame boundary point having a certain period and receives an orthogonal code to make a call. As the number of orthogonal codes assigned to a voice user varies, the number of orthogonal codes usable for packet data transmission varies. The hatched portion in FIG. 10 indicates that the number of orthogonal codes usable for packet data transmission changes as the number of orthogonal codes assigned to the voice user varies. Regardless of the number of orthogonal codes available in the forward direction, the terminal measures the CIR of the packet data channel in smaller (or independent) time units than one frame, and based on this measured CIR, the maximum possible packet rate Can be determined. Orthogonal codes required to transmit data are inherently proportional to the data rate. In the period of frame A, it is shown that the number of orthogonal codes that can be allocated for a packet is almost equal to the number of orthogonal codes required to send an average maximum data rate determined based on the CIR. In the period of frame B, since the required number of orthogonal codes is smaller than the number of currently available orthogonal codes, it shows that there is no problem in transmitting at the maximum data rate determined based on the CIR. The frame A section and the B section are sections in which orthogonal codes allocated for packets are sufficient. However, although the CIR is sufficient in the frame C section and the D section, the packet data cannot be transmitted at the maximum physical rate based on the CIR because the orthogonal codes allocated for the packets are not sufficient. That is, it can be seen that the forward packet data rate should be determined under the condition that satisfies both the CIR value and the required number of orthogonal codes.

As shown in FIG. 2, in the physical link for data transmission of a mobile communication system, forward error correction coding and symbol repetition for packet data bits sent from an upper layer are performed. ), Modulation processes such as QPSK / QAM modulation / mapping, demultiplexing, and spreading by orthogonal codes are performed. Such various parameters during the modulation process-coding rate, repetition rate, symbol mapping method, output number of demultiplexing, etc.-and the number of available orthogonal codes It depends on the transmission rate of packet data determined accordingly. According to the present invention, in the situation where the number of orthogonal codes available for packet data transmission varies continuously according to the number of voice users, the packet data transmission rate is determined at the terminal in consideration of the number of available orthogonal codes and the CIR measured at the terminal simultaneously. It is to be noted that the present invention relates to determining the modulation and demodulation parameters accordingly.

Before describing the rate control operation according to an embodiment of the present invention in detail, the terms to be described below are defined as shown in Table 2 below.

Rm: Maximum possible transmission rate determined based on the measured CIR Nw: Number of available orthogonal codes excluding voice users Nm: Maximum available orthogonal codes without voice users r: Sequence repetition number in Ns slots per packet.Ns: Number of slots per packet.p: Packet symbol size after I / Q demultiplexing (for I-arm or Q-arm each) c: Total number of chips per Packet (for I-arm or Q arm each) b: Total number of bits per packet before QPSK / QAM mapping (before I / Q branching)

In Table 2, the maximum possible data rate Rm is determined based on the use of all Walsh codes, and is represented by a data rate table (DR) of Table 3 to be described later.

11 illustrates a configuration of a forward link transmitter for a data traffic channel having a rate control function according to an embodiment of the present invention. The structure of such a transmitter is based on the configuration shown in FIG. 2 described above. Hereinafter, only the components related to the rate control will be described.

Referring to FIG. 11, packet data of a predetermined length transmitted from a medium access control (MAC) layer is subjected to turbo coding and channel interleaving for forward error correction. After that, a symbol mapping (or modulation) process of QPSK / 8PSK / 16QAM is performed for each data rate. The data that has undergone the symbol mapping process is divided into a first channel I-ch symbol and a second channel Q-ch symbol through a 1-to-2 demultiplexer 215. The I-ch symbol and the Q-ch symbol are spread to 32 Walsh codes by the Walsh spreader 216, which can be implemented as a 1-to-Nw demultiplexer, respectively. This process is repeated after one cycle of a symbol that constitutes a packet is transmitted for a time corresponding to a fixed number of slots. The repetition rate at this time has a value greater than or equal to '1' when the data transmission rate is low, but has a value near '1' when the data transmission rate is high. The parameters in each of these modulation processes (the number of output stages, the repetition rate, and the number of slots required to transmit one packet) of the demultiplexer 215 immediately before Walsh spreading depend on the number of Walsh codes available. The DRC controller 240 receives Walsh Code Allocation Information assigned to the base station itself, receives DRC information and sector indicator (SI) information from the terminal, and receives the above parameters. Adjust according to the rate control operation suggested in. DRC control operation according to an embodiment of the present invention by the forward link transmitter will be apparent from the following description.

Referring again to FIG. 1A, one slot of a packet data channel includes a preamble and a packet data whose length is determined according to a data rate. One packet data is transmitted over one or more slots. The preamble is located at a position just before one packet data is transmitted, and its length depends on the transmission rate.

Table 3 below shows numerical values representing modulation parameters and packet structure for each data rate of a packet data channel when all 28 orthogonal codes available for a packet are available. For example, if the data rate (DR) index is 6, one packet (©) is composed of 768 bits, which includes 1/3 coding, QPSK / 8PSK / 16QAM symbol mapping, and demultiplexing. After coarse, the total number of symbols (ⓕ) to be transmitted per packet is 1152. The 1152 symbols are transmitted for one slot time. Since only 28 of the 32 space Walsh codes are available, the maximum number of transmittable symbols is 1288. Therefore, after 1152 symbols, the total number of symbols per packet, are transmitted once, an additional 1288-1152 = 136 symbols are transmitted. The last column of (Table 3) below shows how many repetitive transmissions can occur during a given number of slots (ⓑ).

12 illustrates a slot structure when a forward link transmitter transmits a packet at a transmission rate of 614.4 kbps according to an embodiment of the present invention. This slot structure is a case where a packet is transmitted at a transmission rate (614.4kbps / 768 / 1slot) corresponding to DR Index 6 of Table 3. The preamble subchannel is 64 chips long, time division multiplexed at the beginning of one slot, and data symbols are transmitted to the rest of the slot. Since the total number of symbols to be transmitted is 1152, it is transmitted while sequence repetition 1.19 occurs over a portion except for preamble of one slot.

13 is a diagram illustrating a slot structure when a forward link transmitter transmits a packet at a transmission rate of 307.2 kbps according to an embodiment of the present invention. This slot structure is a case in which packets are transmitted at a transmission rate (307.2 kbps / 768/2 slots) corresponding to DR Index 5 of Table 3, and symbols constituting one packet are transmitted over two slots. Since the number of last columns in the Table 3 is 1.19, one or more symbol sequence repetitions occur for two slots immediately after the 128-chip length preamble transmission located at the very beginning of the first slot.

Referring back to FIG. 3, which shows a structure of a forward MAC channel including a forward Walsh indicator channel indicating an orthogonal code allocation information of a base station, the information of an orthogonal code allocated for a packet user is at least two slots before packet data transmission starts. The terminal should be informed. In the example of the present invention, since packet data symbols are spread by a 32 chip Walsh code, the presence or absence of each Walsh code W0 to W31 is notified based on the Walsh code having 32 chip lengths. In this case, it is assumed that the voice or packet user can use the remaining Walsh codes W4 to W31 except the Walsh codes W0 to W3 allocated for the joint signaling of the entire mobile communication system.

14 illustrates a configuration of a forward link receiver for a data traffic channel having a rate control function according to an embodiment of the present invention. This forward link receiver (terminal receiver) corresponds to the forward link transmitter (base station transmitter) having the rate control function shown in FIG. 11 described above, and is based on the configuration shown in FIG. 7 described above. Only the components related to the description will be described.

Referring to FIG. 14, the reverse link of the modulation process in the forward link transmitter is performed in the forward link receiver. In the forward link receiver, processes such as Walsh despreading, parallel to serial multiplexing, symbol combining as much as repetition rate, demapping, and decoding are performed. . The parameters in each process of demodulation-the number of multiplexer outputs after Walsh despreading, the number of symbol combinations, the number of slots required to transmit a packet, etc.-depend on the number of Walsh codes available.

The forward link receiver includes a DRC controller 740 for a DRC control operation according to an embodiment of the present invention. The DRC controller 740 determines the parameters to be used in the Walsh despreader 706, the channel compensator 707, the parallel-to-serial converter 708, and the symbol combiner 709 constituting the demodulator. At this time, unlike the forward link transmitter 240 of FIG. 11, the DRC controller 740 uses the reception CIR of the data channel obtained from the power ratio of the data channel obtained from the packet channel measured from the F-PFI channel receiver and the reception CIR measured using the common pilot channel. Determine the parameters. To this end, the forward link receiver includes a data channel reception C / I meter 720. The forward link receiver also includes a CIR-Rm mapping table 730. The C / I measurer 720 measures the C / I of the data channel using the channel estimate estimated by the channel estimator 717. The channel estimator 717 inputs the Walsh despreaders 715,716 to output an estimate of the data channel. The Walsh despreader 715 inputs the I-channel signal of the common pilot channel and multiplies the pilot Walsh code to output it. The Walsh despreader 716 inputs the Q channel signal of the common pilot channel and multiplies the pilot Walsh code to output it. It will be apparent from the following description of the DRC control operation according to the embodiment of the present invention by the forward link receiver.

FIG. 15 illustrates a channel structure in which a reverse link transmitter transmits DRC information and sector indicator information according to an embodiment of the present invention.

In FIG. 15, a reverse DRC channel is a channel for informing a base station of a transmission rate determined from a terminal. The Reverse Sector Indicator Channel is a channel used by the terminal to select a base station capable of the highest data rate at the time of handoff. The bit repeater 1001 bit repeats the sector indicator channel information a predetermined number of times. Diffuser 1002 Walsh diffuses the output of the bit iterator 1001 by the Walsh code WS. The bit repeater 1003 bit repeats the DRC information by a preset number of times. Diffuser 1004 Walsh diffuses the output of the bit repeater 1003 by the Walsh code WD. Summer 1005 sums the output of spreader 1002 and the output of spreader 1004. For example, the sector indicator channel information may be 3 bits per slot, the DRC channel information may be 4 bits per slot, and the output of the summer 1005 may be 384 binary symbols per slot.

Referring back to <Table 3>, the basic DR table is created based on allocating all 28 (= Nm) except the four already allocated to the common channel for voice user among 32 Walsh codes. However, when the number of available Walsh codes (= Nw) is less than Nm, the number of output terminals of the symbol demultiplexer 215 of FIG. 11 is limited to less than Nm. Therefore, the total symbols of a predetermined packet within a predetermined Ns slot interval are limited. It becomes impossible to transmit. In the DR Index 6 of Table 3, when 768 bits of 614.4kbps are to be transmitted, when the number of orthogonal codes allocated to packet data to the base station is 14 instead of 28, the number of symbols that can be transmitted in one slot is Reduced to 1064 / (14/28) = 532 symbols. Therefore, it is necessary to change the modulation / demodulation value such as increasing the total number of slots for transmitting one packet or reducing the number of symbols in the packet. As a result, when Nw <Nm, the modulation / demodulation parameter of [r, p, Ns, code rate, coded symbol mapping method] may be changed in order to transmit the total symbol of one packet at least once. However, since the code rate and the coded symbol mapping method are determined according to the maximum possible transmission rate that directly reflects the CIR characteristics of the wireless transmission channel, it is not desirable to change according to Nw.

As shown in FIG. 14, the present invention down-regulates the modulation / demodulation parameter (r, Ns, p) determined at the maximum possible transmission rate (Rm) determined based on the CIR in consideration of the number of available orthogonal codes (Nw). The terminal is equipped with a DRC controller 740 having a function to. In this case, a DRC controller 240 as shown in FIG. 11 having a structure similar to that of the DRC controller 740 provided in the terminal is provided to operate a modulator, or a demodulation parameter value determined by the terminal is transmitted through a reverse channel to be modulated. Note that it can be used as a parameter.

16 is a diagram showing the configuration of an apparatus for a rate control operation according to an embodiment of the present invention.

Referring to FIG. 16, a terminal receiver 1101 receives an RF signal from a base station and converts the RF signal into an IF signal. This receiver 1101 corresponds to the components shown in FIG. The packet data channel demodulator 1102 is for demodulating packet data transmitted from a base station. The packet data channel demodulator 1102 corresponds to components 706 to 712 of FIG. Pilot Channel Demodulator & CIR Meter 1104 receives a forward pilot channel signal and measures a received CIR from the received forward pilot channel signal. The CIR meter 1104 is a component corresponding to 720 of FIG. 14. The CIR measured from the forward pilot channel is converted to the received CIR of the data channel by the power ratio of the data channel demodulated by the F-PFI channel demodulator 1110 and sent to the DRC controller 1105. The Walsh indicator channel demodulator 1107 receives and demodulates a forward Walsh indicator channel signal indicating base station Walsh code assignment information of a previous frame (eg, 20 ms frame). The Walsh indicator channel demodulator 1107 is a component corresponding to 801, 802, 804, 805, and 808 of FIG. The CIR-Rm mapping table 1109 maps the CIR measured by the CIR meter 1104 and the possible data rates when using the largest Walsh code (eg, 28). The CIR-Rm mapping table 1109 is illustrated as a CIR-Rm mapping table 730 in FIG. 14, and may be configured in the form of a lookup table as shown in Table 3 above. The data rate controller 1105 selects a base station that can be transmitted at the maximum transmission rate using previously transmitted Walsh information of the base station belonging to the received active set. The rate controller 1105 is shown as a DRC controller 740 in FIG. 14. In addition, the rate controller 1105 transmits the DRC information, which is the rate information, and the base station selection information sector indicator, to the base station through the reverse DRC channel modulator 1106 and the reverse sector indicator channel modulator 1108, respectively. The reverse DRC channel modulator 1106 and sector indicator channel modulator 1108 are configured as shown in FIG. 15. The terminal transmitter 1103 converts the DRC information from the reverse DRC channel modulator 1106 and the sector indicator from the reverse sector indicator channel modulator 1108 into an RF signal suitable for transmission, and transmits it to the base station. In addition, the DRC controller 1105 calculates a demodulation parameter of the packet channel in consideration of the Walsh code information and the transmission rate determined by the CIR at the same time, and sets the demodulation parameter specified in the packet channel demodulator 1102 at the time of demodulation. The operation of demodulation parameter calculation by the DRC controller 1105 will become apparent from the description associated with FIG. 18 to be described later.

FIG. 17 is a view illustrating operation timing between a forward Walsh indicator channel, a forward pilot channel, a forward packet data channel, a reverse DRC channel, and a reverse sector indicator (SI) channel during a rate control operation according to an embodiment of the present invention.

Referring to FIG. 17, a frame (eg, 20 ms) of voice data has a length in time equal to 16 packet transmission slots (1.25 ms each). When determining the data rate for the packet slot overlapping the current frame time (i + 1), the (i + 1) th frame includes Walsh code information transmitted through the forward Walsh indicator channel (F-WICH) in the previous frame (i). Receive and use until started. As already described in FIG. 14, the received CIR measurement is obtained by calculating pilot symbol power from the forward pilot channel and converting it to the power ratio of the data channel, and pilot symbol (s) immediately before the start of reverse DRC transmission. Use The mapping of the measured reception CIR value and the maximum possible transmission rate (Rm) may be separately calculated or determined by a field test and stored in the CIR-Rm mapping table 1109 of FIG. 16. The reception CIR measurement of the data channel and the operation of obtaining the maximum possible transmission rate Rm are completed in T1 time (1/2 slot time). The reverse DRC according to the maximum possible transmission rate Rm is transmitted as an index value in the second half of each slot. The index value of the DRC may be applied from the second forward slot after the slot in which the DRC transmission is made in consideration of the transmission time in the radio channel and the processing delay time in the base station. If the terminal is able to receive packet data from the best base station at the same time because the terminal is in the handoff region, the terminal measures the CIR from each base station and then transmits the data rate in consideration of all Walsh information of each base station. The maximum index of the base station is transmitted to the reverse sector indicator channel in synchronization with the DRC transmission time. After transmission of the reverse DRC (R-DRC) channel and the reverse sector indicator (R-SI) channel, the Walsh code information of the base station is used for T2 time (second half of one slot and next slot). Determine the demodulation parameters for the actual rate and allow the operation to be performed accordingly.

The processing flow according to the algorithm for determining the demodulation parameter and causing the operation to be performed is shown in FIG. This process flow is based on the assumption that the current slot already knows the base station orthogonal code information received in the frame of the previous voice data before determining the data rate. The base station performs the same operation as the DRC algorithm of the terminal during the T3 time (second half of the next slot) according to the sector indicator (R-SI) and the reverse rate (R-DRC) information received in the reverse direction, and performs modulation parameters. Calculate In this way, the modulation / demodulation parameters (repetition rate, slot number, packet symbol number) calculated by the terminal and the base station are set at the base station packet channel transmitter and the terminal packet channel receiver at the end of T3 time and operate simultaneously.

18 is a flowchart illustrating a processing flow of a rate control operation by a DRC controller included in a terminal according to an embodiment of the present invention. This flowchart can be described consisting of the following seven steps.

<Step 1: Step 1201, 1202> The Walsh indicator channel demodulator 1107 of FIG. 16 receives Walsh code assignment information every preset frame 20ms. The CIR measurer 1104 measures the CIR of the received packet channel from the forward pilot within the time T1 of FIG. 17 and converts the received CIR of the data channel using the power ratio information of the data channel obtained from the F-PFI.

<Step 2: Steps 1203 and 1204> When the UE is not currently in a handoff situation, the DRC controller 1105 uses the CIR-Rm mapping table 1109, which is a look-up table that calculates the maximum data rate according to the CIR measured by the CIR meter 1104. And select and transmit the selected maximum data rate to the base station through the reverse DRC channel 1106. The CIR-Rm mapping table 1109 may be configured as shown in Table 3 as an example.

On the other hand, when the terminal is in a handoff situation, the DRC controller 1105 inputs all the CIRs from the pilot signals of each base station measured by the CIR measuring instrument 1104, and maps the maximum data rates according to the input CIRs to the CIR-Rm mapping. Select from Table 1109. The DRC controller 1105 then multiplies each selected maximum data rate DR by the ratio Nw / Nm of the available orthogonal code number Nw to the maximum orthogonal code number Nm. The DRC controller 1105 selects a base station having a maximum value among the multiplication results, and transmits a sector indicator (SI) and DRC information to the selected base station. The operation of this step can be summarized as Equation 1 below.

SI = [Max i | DRi * Nw / Nm, i = 0 ~ sector_no], sector_no is the number of active SET base stations

Step 3: Step 1205 The DRC controller 1105 determines whether (Nw <Nm). If (Nw <Nm), the following <Step 4> is performed. In contrast, when (Nw = Nm), an operation of selecting a modulation / demodulation parameter (r, Ns, p) from the CIR-Rm mapping table 1109 is performed.

<Step 4: Step 1206> The DRC controller 1105 calculates a repetition number 'r_new' by Equation 2 below.

r_new = c * (Nw / No) / p

<Step 5: step 1207> The DRC controller 1105 determines whether (r_new> 1 * prune_rate). Here, prune_rate is a real number close to 1, and if the r value calculated in <Step 4> is less than 1 but close to 1, for example, if prune_rate = 0.9, more than 90% of one packet is transmitted once in Ns. It means. If (r_new> 1 * prune_rate), the DRC controller 1105 performs <Step 6-1> below. If (r> 1 * prune_rate), the DRC controller 1105 performs <Step 6-2> below.

<Step 6-1: Step 1208> The DRC controller 1105 selects the sequence combining repetition number as r_new (> 1 * prune_rate) obtained in <step 4>. The number of input branches of the symbol multiplexer 708 of FIG. 14 is Nw. The number of symbols p of the packet and the number Ns of slots for one packet transmission are maintained. That is, in step 1208, the DRC controller 1105 changes the value of r to the value of r_new, and maintains the values of Ns and p from the CIR-Rm mapping table 1109 without changing the values of Ns and p.

<Step 6-2: Steps 1209 and 1210> When the sequence combining repetition number r_new is smaller than 1 * prune_rate, the DRC controller 1105 may perform any one of two options (Option A and B).

Option A (step 1209) : The first selection method is a method of increasing the slot length. That is, the DRC controller 1105 increases Ns, which is the number of slots required for one packet transmission, so that the p symbol, which is the total number of symbols of at least one packet, can be transmitted once. At this time, since Ns is increased, since the transmission continues during the increased slot, the actual value of r has a range of 1 <r <2. At this time, p, the number of symbols constituting a packet, does not change. If the number of orthogonal codes is not Nw, the number of data chips required to transmit the p symbol is as shown in Equation 3 below. (1536 chips in the example of the present invention), Ns_new, which is the number of slots required to transmit one packet, is calculated as in Equation 4 below. The value of p does not change and remains at the value of p from the CIR-Rm mapping table 1109.

In Equation 4, a means a minimum integer greater than a.

Option B (step 1210) : The second selection method is a method of reducing the total number of symbols p of a packet to be transmitted, and by this method, only some symbols are transmitted. That is, as the number of orthogonal codes, only the number of symbols that can be transmitted in the basic Ns slots is transmitted. In this case, the number of transmittable symbols is calculated as in Equation 5 below, and is transmitted only once as r = 1, and the value of Ns is maintained as the value of Ns from the CIR-Rm mapping table 1109 as it is.

p_new = c * Nw / No

The DRC controller 1105 repeats the above-described operations from <Step 1> to <Step 6-1 / 6-2> for all base stations included in the current active set, and then selects a base station capable of maximum transmission rate. The sector indicator is transmitted to the corresponding base station.

<Step 7: Step 1211> The DRC controller 1105 sets the determined parameters r, Ns, and p to the packet data channel demodulator 1102 of FIG. At this time, the components of the channel demodulator 1102 correspond to the Walsh despreader 706, the channel compensator 707, the parallel-serial converter 708, and the sequence combiner 709.

On the other hand, the parameters calculated by the DRC controller 1105 may be transmitted to the base station and used in signal modulation at the base station transmitter. Instead, the DRC controller 240 of the base station illustrated in FIG. 11 may extract a modulation parameter after receiving the DRC from the terminal and performing the same process as in <Step 3> to <Step 6-1 / 6-2>. .

19 is a flowchart illustrating a processing flow of a transmission rate and modulation parameter determination operation by a DRC controller included in a base station according to an embodiment of the present invention.

Referring to FIG. 19, the base station transmits orthogonal code information to the terminal every 20ms frame. In addition, it is determined whether there is a transmission request from the terminal by monitoring the reverse DRC and the sector indicator received from the terminal in every slot. If the reverse sector indicator points to this base station, the maximum transmittance can be known from the DR INDEX value received at the same time. Unlike the terminal, the base station knows the currently available orthogonal code. Therefore, the DRC controller 240 of the base station shown in FIG. 11 calculates a modulation parameter through the same process as in <STEP 3> to <STEP 7> of FIG. 18 by using orthogonal code information usable with DR INDEX. Set to.

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

As described above, according to the present invention, the demodulation parameter of the channel is appropriately changed in the terminal according to the number of orthogonal (walsh) codes available in the mobile communication system for voice and packet data services, and the modulation parameter of the channel is appropriately changed in the base station. There is an advantage that enables forward packet data transmission at the maximum rate at the same time as voice (CIRCUIT) calls.

Claims (18)

A method for adaptively adjusting a parameter for demodulation in a terminal of a mobile communication system for voice and packet data services, Obtaining a maximum data rate estimated in response to the received signal-to-noise ratio measured through the pilot channel; And adjusting a symbol repetition rate according to the maximum data rate and orthogonal code information allocated to a base station. A method for adaptively adjusting a parameter for demodulation in a terminal of a mobile communication system for voice and packet data services, Obtaining a maximum data rate estimated in response to the received signal-to-noise ratio measured through the pilot channel; Calculating a symbol repetition rate according to the maximum data rate and orthogonal code information allocated to the base station; Determining the symbol repetition rate as a symbol repetition rate for demodulation when the symbol repetition rate is greater than a preset repetition rate; And if the symbol repetition rate is less than the set repetition rate, increasing the number of slots forming a packet. A method for adaptively adjusting a parameter for demodulation in a terminal of a mobile communication system for voice and packet data services, Obtaining a maximum data rate estimated in response to the received signal-to-noise ratio measured through the pilot channel; Calculating a symbol repetition rate according to the maximum data rate and orthogonal code information allocated to the base station; Determining the symbol repetition rate as a symbol repetition rate for demodulation when the symbol repetition rate is greater than a preset repetition rate; And if the symbol repetition rate is smaller than the set repetition rate, reducing the number of symbols in the packet. A method for adaptively adjusting a parameter for demodulation at handoff in a terminal of a mobile communication system for voice and packet data services, the method comprising: Receiving information on an orthogonal code from active set base stations; Obtaining maximum data rates estimated in response to a signal-to-noise ratio of a packet transmission channel from each base station through a pilot channel; Selecting a base station having a maximum data rate by multiplying the obtained maximum data rates by a usage rate of an orthogonal code; And adjusting a symbol repetition rate for demodulation according to the orthogonal code information allocated to the selected base station and the maximum data rate corresponding to the selected base station. A method for adaptively adjusting a parameter for demodulation at handoff in a terminal of a mobile communication system for voice and packet data services, the method comprising: Receiving information on an orthogonal code from active set base stations; Obtaining maximum data rates estimated in response to a signal-to-noise ratio of a packet transmission channel from each base station through a pilot channel; Selecting a base station having a maximum transmission rate by multiplying the obtained maximum transmission rates by a usage rate of an orthogonal code; Calculating a symbol repetition rate according to orthogonal code information allocated to the selected base station and a maximum data rate corresponding to the selected base station; Determining the symbol repetition rate as a symbol repetition rate for demodulation when the symbol repetition rate is greater than a preset repetition rate; And if the symbol repetition rate is less than the set repetition rate, increasing the number of slots forming a packet. A method for adaptively adjusting a parameter for demodulation at handoff in a terminal of a mobile communication system for voice and packet data services, the method comprising: Receiving information on an orthogonal code from active set base stations; Obtaining maximum data rates estimated in response to a signal-to-noise ratio of a packet transmission channel from each base station through a pilot channel; Selecting a base station having a maximum transmission rate by multiplying the obtained maximum transmission rates by a usage rate of an orthogonal code; Calculating a symbol repetition rate according to orthogonal code information allocated to the selected base station and a maximum data rate corresponding to the selected base station; Determining the symbol repetition rate as a symbol repetition rate for demodulation when the symbol repetition rate is greater than a preset repetition rate; And if the symbol repetition rate is smaller than the set repetition rate, reducing the number of symbols in the packet. An apparatus for adaptively adjusting a parameter for demodulation in a terminal of a mobile communication system for voice and packet data services, the apparatus comprising: A lookup table storing a series of maximum data rates corresponding to a series of received signal-to-noise ratios; And a controller for obtaining a maximum data rate stored in the lookup table corresponding to the received signal-to-noise ratio measured through a pilot channel, and adjusting a symbol repetition rate according to the obtained maximum data rate and orthogonal code information allocated to the base station. Device. An apparatus for adaptively adjusting a parameter for demodulation in a terminal of a mobile communication system for voice and packet data services, the apparatus comprising: A lookup table storing a series of maximum data rates corresponding to a series of received signal-to-noise ratios; Obtaining a maximum data rate stored in the lookup table corresponding to a received signal-to-noise ratio measured through a pilot channel, and if the symbol repetition rate calculated according to the obtained maximum data rate and orthogonal code information allocated to a base station is greater than a preset repetition rate And a controller for determining a symbol repetition rate for demodulation and increasing the number of slots forming a packet when the symbol repetition rate is smaller than the set repetition rate. An apparatus for adaptively adjusting a parameter for demodulation in a terminal of a mobile communication system for voice and packet data services, the apparatus comprising: A lookup table storing a series of maximum data rates corresponding to a series of received signal-to-noise ratios; Obtaining a maximum data rate stored in the lookup table corresponding to a received signal-to-noise ratio measured through a pilot channel, and if the symbol repetition rate calculated according to the obtained maximum data rate and orthogonal code information allocated to a base station is greater than a preset repetition rate And a controller for determining a symbol repetition rate for demodulation and reducing the number of symbols in the packet when the symbol repetition rate is less than the set repetition rate. An apparatus for adaptively adjusting a parameter for demodulation at handoff in a terminal of a mobile communication system for voice and packet data services, the apparatus comprising: A receiver for receiving information on an orthogonal code from active set base stations, A lookup table storing a series of maximum data rates corresponding to a series of received signal-to-noise ratios; Obtain the maximum transmission rates stored in the lookup table corresponding to the signal-to-noise ratio of the packet transmission channel from each base station through the pilot channel, and select the base station having the maximum transmission rate by multiplying the obtained maximum transmission rates and the usage rate of the orthogonal code. And a controller for adjusting a symbol repetition rate for demodulation according to orthogonal code information assigned to the selected base station and a maximum data rate corresponding to the selected base station. An apparatus for adaptively adjusting a parameter for demodulation at handoff in a terminal of a mobile communication system for voice and packet data services, the apparatus comprising: A receiver for receiving information on an orthogonal code from active set base stations, A lookup table storing a series of maximum data rates corresponding to a series of received signal-to-noise ratios; Obtain the maximum transmission rates stored in the lookup table corresponding to the signal-to-noise ratio of the packet transmission channel from each base station through the pilot channel, and select the base station having the maximum transmission rate by multiplying the obtained maximum transmission rates and the usage rate of the orthogonal code. The symbol repetition rate is determined as a symbol repetition rate for demodulation when the symbol repetition rate calculated according to the orthogonal code information allocated to the selected base station and the maximum data rate corresponding to the selected base station is greater than a preset repetition rate. And a controller for increasing the number of slots forming one packet when less than the set repetition rate. An apparatus for adaptively adjusting a parameter for demodulation at handoff in a terminal of a mobile communication system for voice and packet data services, the apparatus comprising: A receiver for receiving information on an orthogonal code from active set base stations, A lookup table storing a series of maximum data rates corresponding to a series of received signal-to-noise ratios; Obtain the maximum transmission rates stored in the lookup table corresponding to the signal-to-noise ratio of the packet transmission channel from each base station through the pilot channel, and select the base station having the maximum transmission rate by multiplying the obtained maximum transmission rates and the usage rate of the orthogonal code. The symbol repetition rate is determined as a symbol repetition rate for demodulation when the symbol repetition rate calculated according to the orthogonal code information allocated to the selected base station and the maximum data rate corresponding to the selected base station is greater than a preset repetition rate. And a controller for reducing the number of symbols in the packet when less than the set repetition rate. A method for adaptively adjusting parameters for modulation in a base station of a mobile communication system for voice and packet data services, the method comprising: Receiving rate information from a terminal; And adjusting a symbol repetition rate according to the rate information and the orthogonal code assignment information. A method for adaptively adjusting a parameter for demodulation in a base station of a mobile communication system for voice and packet data services, Receiving rate information from a terminal; Calculating a symbol repetition rate according to the rate information and the orthogonal code assignment information; Determining the symbol repetition rate as a symbol repetition rate for demodulation when the symbol repetition rate is greater than a preset repetition rate; And if the symbol repetition rate is less than the set repetition rate, increasing the number of slots forming a packet. A method for adaptively adjusting a parameter for demodulation in a base station of a mobile communication system for voice and packet data services, Receiving rate information from a terminal; Calculating a symbol repetition rate according to the rate information and the orthogonal code assignment information; Determining the symbol repetition rate as a symbol repetition rate for demodulation when the symbol repetition rate is greater than a preset repetition rate; And if the symbol repetition rate is smaller than the set repetition rate, reducing the number of symbols in the packet. An apparatus for adaptively adjusting parameters for modulation in a base station of a mobile communication system for voice and packet data services, the apparatus comprising: A receiver for receiving rate information from a terminal; And a controller for adjusting a symbol repetition rate according to the rate information and the orthogonal code assignment information. An apparatus for adaptively adjusting a parameter for demodulation in a base station of a mobile communication system for voice and packet data services, the apparatus comprising: A receiver for receiving rate information from a terminal; If the symbol repetition rate calculated according to the transmission rate information and the orthogonal code allocation information is greater than the preset repetition rate, the symbol repetition rate is determined as a symbol repetition rate for demodulation, and one packet when the symbol repetition rate is smaller than the set repetition rate. And a controller for increasing the number of slots forming the slot. An apparatus for adaptively adjusting a parameter for demodulation in a base station of a mobile communication system for voice and packet data services, the apparatus comprising: A receiver for receiving rate information from a terminal; If the symbol repetition rate calculated according to the rate information and the orthogonal code allocation information is greater than a preset repetition rate, the symbol repetition rate is determined as a symbol repetition rate for demodulation, and when the symbol repetition rate is smaller than the set repetition rate, the number of symbols in the packet is reduced. Said controller comprising a controller.