KR100678150B1 - System for link adaptation and method thereof in code division multiple access system - Google Patents

Abstract

The present invention relates to a link adaptation system and method for a code division multiple access system. The present invention relates to a link adaptation system and a method for requesting the maximum data rate that a terminal can receive in the HDR scheme through data rate control information. Considering only the change in the maximum data rate transmitted, it is reported through the data rate change control information, and the CDMA 2000 method reports the pilot signal strength of the terminal through a pilot strength measurement message and then receives the received signal received by the terminal. The state change is reported through the received signal-to-interference ratio control information in consideration of only the change in the transmitted pilot signal strength.

Data rate control information, data rate change control information, pilot signal strength measurement message, received signal to interference ratio control information, power control information

Description

Link adaptation system and method of code division multiple access system {SYSTEM FOR LINK ADAPTATION AND METHOD THEREOF IN CODE DIVISION MULTIPLE ACCESS SYSTEM}             

1 is a data rate control information symbol transmission diagram of the HDR method according to the prior art

2 is a HDR reverse link transmission apparatus according to the prior art

3 is a diagram illustrating channel transmission according to the operation of the time division multiplexer of FIG.

4 is a diagram illustrating a CDMA 2000 type pilot signal strength measurement message transmission according to the prior art;

5 is a CDMA 2000 reverse link transmission apparatus according to the prior art

6 is a diagram illustrating channel transmission according to the operation of the multiplexer of FIG. 5.

7 is a diagram illustrating transmission of data rate control information symbols and data rate change control information symbols in an HDR scheme according to an embodiment of the present invention;

8 is a HDR reverse link transmission apparatus according to an embodiment of the present invention

9 is a diagram illustrating transmission of a data rate control information symbol and a data rate change control information symbol according to the switch operation of FIG. 8;

10 is a block diagram showing an internal configuration of a data rate change control information generating device according to an embodiment of the present invention.                 

11 is a block diagram showing an internal configuration of an apparatus for detecting data rate change control information according to an embodiment of the present invention.

12 is a flowchart illustrating an operation process of a terminal for link adaptation in the HDR scheme according to an embodiment of the present invention.

13 is a flowchart illustrating an operation process of a base station for link adaptation in the HDR scheme according to an embodiment of the present invention.

14 is a diagram illustrating transmission of a pilot signal strength measurement message and a received signal-to-interference ratio control information symbol in a CDMA 2000 scheme according to an embodiment of the present invention;

15 is a CDMA 2000 reverse link transmission apparatus according to an embodiment of the present invention.

FIG. 16 is a diagram illustrating transmission of pilot, power control information, and received signal-to-interference ratio control information according to the switch operation of FIG. 15.

17 is a block diagram showing an internal configuration of an apparatus for generating a reception signal to interference ratio control information according to an embodiment of the present invention.

18 is a block diagram showing an internal configuration of a reception signal to interference ratio control information detecting apparatus according to an embodiment of the present invention.

19 is a flowchart illustrating an operation process of a terminal for link adaptation using the CDMA 2000 scheme according to an embodiment of the present invention.

20 is a flowchart illustrating an operation process of a base station for link adaptation using the CDMA 2000 scheme according to an embodiment of the present invention.

TECHNICAL FIELD The present invention relates to code division multiple access systems, and more particularly, to a link adaptation system and method for increasing data processing capacity.

As the mobile communication service develops, there is a tendency to develop from the conventional voice service that provided only voice to data service for video communication and the Internet as well as voice service. However, since the data service has a greater amount of information sent from the base station to each terminal than the amount of information sent from the mobile station (MS) to the base station (BS), the forward data is higher than the reverse data throughput. Higher throughput is required. There are a plurality of methods for improving the forward data throughput, and a link adaptation method will be described.

In the link adaptation method, each terminal that receives a data service or wants to receive a data service estimates and predicts a signal state of a forward link received by the terminal, and then estimates and predicts the signal. When the information on the signal state of the forward link is reported to the base station, the base station has the information on the signal state of the forward link reported by the terminal to the terminal capable of data service and the received signal state of the data service capable terminal Means a method of transmitting data in the selected method by selecting an appropriate data transmission method. The selectable data transmission method includes a modulation / demodulation method, an error correction method, a frame length, a data rate, and the like, and through the link adaptation method, it is possible to provide an optimal data throughput according to a change in a reception channel of each terminal. will be.

There are two methods for providing data services in a synchronous code division multiple access (CDMA) system. The first method is a high data rate (HDR) method using a dedicated frequency channel (FA) for data service, and the second method is a CDMA2000 method using the same frequency channel to simultaneously perform not only data service but also voice service. to be. The HDR method will be described first of the respective data service providing methods.

The HDR method estimates and predicts a signal state of a forward link based on a signal received from a base station by a terminal, and transmits information about the estimated and predicted signal state of a forward link to data rate control information (DRC: data rate) of a reverse link. The data transmission rate control information symbol is transmitted through the control channel to report the state of the terminal itself to the base station. In the transmitting of the data rate control information symbol, first, a terminal predicts and estimates a carrier to interference ratio (C / I) of a forward link through a pilot channel of a forward link to interfere with the received signal to interference. A process of determining a maximum data rate that can be received in a non-circumstance, mapping the determined maximum data rate into a 4 bit data rate control information symbol, and then transmitting the data through the reverse data rate control information channel. That is, the terminal requests the base station to receive data service at the maximum data rate that the terminal itself can receive by transmitting the data rate control information symbol to the base station.

Table 1 below describes a data rate control information symbol determination rule for mapping the data rate to a 4 bit data rate control information symbol.

DRC symbol Rate (kbps) DRC symbol Rate (kbps) 0x0 38.4 0x8 1228.8 0x1 76.8 0x9 1843.2 0x2 102.4 0xA 2457.6 0x3 153.6 (short) 0xB invalid 0x4 204.8 0xC 153.6 (long) 0x5 307.2 (short) 0xD 307.2 (long) 0x6 614.4 0xE invalid 0x7 921.6 0xF null rate

When the terminal determines the data rate control information symbol, the determined data rate control information symbol is transmitted to a base station through a reverse data rate control information channel, and the data rate control information symbol determined through the reverse data rate control information channel. A process of transmitting will be described with reference to FIG. 1.

1 is a data rate control information symbol transmission diagram of the HDR method according to the prior art, and is a transmission diagram illustrating a method of transmitting the determined data rate control information symbol according to a slot flow. The slot 111 has a length of 1.67 ms, and the data rate control information symbol is transmitted in units of (1.67 ms slots) XN (N = 1, 2, 4), and FIG. 1 shows the data rate control information symbol. The case of transmission in the unit of 1.67ms slot is shown. All data rate control information symbols described below are assumed to be transmitted in units of 1.67 ms slots. Since the data rate control information symbol starts to be transmitted 1/2 slot after the start point 112 of the slot 111, the start point 113 of the data rate control information symbol is the start point of the slot 111 ( When the slot is 1/2 slot and the transmission unit of the data rate control information symbol is a 1.67ms slot, the terminal transmits the data rate control information symbol every slot.

A reverse link transmission apparatus of a terminal for transmitting the data rate control information symbol will be described with reference to FIG. 2. The channel configuring the reverse link includes a pilot channel, a medium access channel (MAC) channel for transmitting a reverse rate indicator (RRI) symbol and a data rate control information symbol, a traffic packet and control information ( There is a traffic channel for transmitting a control packet. Each of the channels is modulated into a transmission signal through a respective transmitter, and a pilot channel transmitter 511 transmits the pilot channel, an RRI channel transmitter 512 transmits the RRI symbol, and transmits the data rate control information channel. The device 513 modulates the data rate control information symbol, and the traffic / control channel transmitter 515 modulates the traffic and control information into a transmission signal. The signals output from the pilot channel transmitter 511, the RRI channel transmitter 512, and the data rate control information channel transmitter 513 are respectively output to a time division multiplexer (MUX) 514, and the traffic / The signal output from the control channel transmitter 515 is output to the complex spreader 516. The time division multiplexer 514 may include a pilot transmission signal, an RRI symbol transmission signal, output from each of the pilot channel transmitter 511, the RRI channel transmitter 512, and the data rate control information channel transmitter 513. The data rate control information symbol transmission signal is time-division multiplexed and output to the complex spreader 516. The complex spreader 516 complexly spreads the time division multiplexed signal by the time division multiplexer 514 and the output signal of the traffic / control channel transmitter 515 and then transmits the complex spreader.

Herein, an operation of the time division multiplexer 514 will be described with reference to FIG. 3. As shown in FIG. 3, the time division multiplexer 514 punctures a pilot channel in units of 64 chips to insert a data rate control information channel, and punctures a second 64 chip of the punctured pilot channel to RRI. Insert a channel. Thus, the time division multiplexer 514 time division multiplexes the pilot channel transmission signal, the RRI symbol signal, and the data rate control information symbol signal to output the complex spreader 516 to the complex spreader 516.

Second, the CDMA 2000 method among the data service providing methods will be described.

In the CDMA 2000 scheme, the terminal estimates and predicts a signal state of a forward link, and transmits the estimated and predicted signal state of a forward link in a message format through a traffic channel of a reverse link to the base station. It means how to report. In this case, the terminal reports its received signal state, the terminal first predicts and estimates the pilot signal reception ratio through a forward link pilot channel, and the pilot has a pilot signal to interference ratio value with the estimated value. Generate a Pilot Strength Measurement Message (PSMM). The pilot signal strength measurement message (PSMM) may be obtained as a sum of Ec / Io. Ec denotes pilot energy per chip, and Io denotes total received energy (including signal and signal noise). The terminal generates the pilot signal strength measurement message and transmits the pilot signal strength measurement message to a base station through a reverse traffic channel. The period in which the terminal reports the pilot signal strength measurement message to the base station is 80 msXN (N: integer).

When the terminal generates a pilot signal strength measurement message, the generated pilot signal strength measurement message is transmitted to a base station through a reverse traffic channel, and the pilot signal strength measurement message is transmitted through the reverse traffic channel. This will be described with reference to 4.

4 is a diagram illustrating a CDMA 2000 type pilot signal strength measurement message transmission according to the prior art, and in particular, illustrates a method of transmitting a pilot signal strength measurement message generated by a terminal over time. In the CDMA 2000 system, each traffic is transmitted in units of 20ms frame, and each 20ms frame is composed of 16 power control groups. FIG. 4 illustrates a case in which the terminal inserts the generated pilot signal strength measurement message to transmit a traffic frame 212 and subsequently transmits a traffic frame 215 that does not include a pilot signal strength measurement message. In the reverse link, a traffic channel and a pilot channel are transmitted together. The pilot channel of the reverse link includes a pilot signal 213 and a power control bit (PCB) 214 for each power control group on a power control group 211 basis. 4 shows that two power control groups at the end of traffic 212 including the pilot signal strength measurement message are transmitted, and the first five power control groups of traffic 215 without the pilot signal strength measurement message are transmitted. It shows the case that it is.

Here, the reverse link transmission apparatus of the terminal for transmitting the pilot signal strength measurement message symbol will be described with reference to FIG. 5. First, power control information generated for power control is input to an iterator 611, and the iterator 611 repeatedly outputs the input power control information to a multiplexer (MUX) 612. The repeater 611 repeats the power control information by 384 chips corresponding to a quarter power control group. The multiplexer 612 multiplexes the power control information signal repeatedly output from the iterator 611 and the pilot channel and outputs the multiplexer 614 to the spreader 614. The pilot signal strength measurement message / traffic channel transmitter 613 modulates the generated pilot signal strength measurement message and traffic into a transmission signal and outputs the modulated signal to the spreader 614. The spreader 614 spreads and transmits the signal output from the pilot signal strength measurement message / traffic channel transmitter 613 and the signal output from the multiplexer 612. Here, the operation of the multiplexer 612 will be described with reference to FIG. 6.

As shown in FIG. 6, one power control group (PCG) is divided into four sections, and the first three sections are transmitted by inserting pilot signals and the last one sections by inserting power control information. Multiplex it to send.

As described above, in the link adaptation method for improving the data throughput of the forward link in the HDR method, even when there is no traffic of the forward link for a specific terminal, the specific terminal reports its maximum data rate. In order to do so, the data rate control information symbol must be continuously transmitted to the base station. That is, all terminals connected to the base station and data service should always transmit data rate control information symbols to the base station through the pilot channel of the reverse link. As such, when all terminals in the base station always transmit data rate control information symbols to the base station through the reverse link pilot channel, the data rate control transmitted by all the terminals when the base station receives the reverse link signal of a specific terminal Information symbols act as interference. Therefore, as the number of terminals connected to the base station to receive the data service increases, the effect of interference on the base station received signal is further increased, and for any more interference effect, the base station receives the reverse link signal at all. Sometimes it can't be done. Therefore, in such a situation, the number of terminals that can be connected to the base station for data service can no longer increase, and more than a certain number of terminals can not be connected to the base station for data service. Therefore, the data rate control information symbol transmission method in the conventional HDR method has a problem that limits the number of terminals that can be connected for data service.

In addition, in the link adaptation method for improving the data throughput of the forward link in the CDMA 2000 scheme, the terminal generates a pilot signal strength measurement message according to the state of the received signal and reports its received signal state to the base station. The transmission period of the pilot signal strength measurement message reported by the terminal is fixed in multiples of 80 ms. That is, as in the CDMA 2000 scheme, a multiple of the 80 ms transmission period of the pilot signal strength measurement message is larger than the transmission period necessary for correctly reporting the changed reception signal state of each terminal, making it difficult to properly adapt the link. For proper link adaptation, the terminal must report its own signal status to the base station corresponding to the rate at which its signal status changes. As in the conventional CDMA 2000 system, when the terminal receives its own signal state to the base station in multiple transmission periods of 80ms, the link adaptation becomes difficult when the state of the received signal of each terminal changes faster. There is a problem that it becomes difficult to improve the throughput.

It is therefore an object of the present invention to provide a link adaptation system and method for increasing the data processing capacity of a code division multiple access system.

Another object of the present invention is to provide a link adaptation system and method for increasing the number of terminals that can be connected to receive a data service in a code division multiple access system.

It is still another object of the present invention to provide a link adaptation system and a method for adaptively reporting a state change of a terminal reception signal for receiving a data service in a code division multiple access system.

It is another object of the present invention to provide a link adaptation system and method for minimizing received signal interference.

The terminal of the HDR system of the present invention for achieving the above objects is the signal-to-interference of the received signal after obtaining the data rate control information transmission period specifying the slot for transmitting the data rate control information symbol and the data rate change control information symbol from the base station Determine the maximum data rate by estimating the ratio, determine the maximum data rate, and transmit data rate control information including the maximum data rate information in the data rate control information symbol transmission slot to a base station, and transmit the data rate control information. After transmission, the data rate change control information is generated by calculating a difference between the maximum detected data rate and the currently detected maximum data rate to control the maximum change of the data rate. Characterized in that the transmission to the station.

The base station of the HDR system of the present invention for achieving the above object is to receive a signal after determining the data transmission rate control information transmission period to be transmitted to the terminal, when the time point of receiving the signal is a data rate control information transmission slot Detects a data rate control information symbol to detect a maximum receivable data rate of the terminal, and detects a data rate change control information symbol when the time point at which the signal is received is a data rate change control information transmission slot; And detecting the beam, and updating the maximum receivable data rate of the terminal according to the detected data rate change control information and transmitting the same to the terminal.

CDMA 2000 terminal of the present invention for achieving the above objects is obtained from the base station after receiving the received signal-to-interference ratio transmission period designating the slot for transmitting the pilot signal strength measurement message and the received signal-to-interference ratio control information symbol After generating a pilot signal strength measurement message by estimating a pilot received signal-to-interference ratio, and transmitting the generated pilot signal strength measurement message to the base station in the pilot signal strength measurement message transmission interval, the previous pilot received signal-to-interference ratio and the The received signal-to-interference ratio is mapped to the received signal-to-interference ratio control information and transmitted to the base station.

The CDMA 2000 base station of the present invention for achieving the above objects is a signal received after receiving the signal-to-interference ratio control information transmission period and transmits to the terminal, the time point at which the signal is received is a pilot signal strength measurement message In the transmission period, the pilot signal strength measurement message is detected from the received signal and mapped to a pilot reception signal-to-interference ratio, and when the signal reception time is a reception signal-to-interference ratio control information transmission period, the reception signal-to-interference ratio is received from the received signal. The control information symbol is detected and mapped to a pilot reception signal-to-interference ratio, and the received signal-to-interference ratio of the detected pilot signal strength measurement message and the received signal-to-interference ratio of the control signal symbol are added to the pilot reception signal-to-interference of the terminal. Characterized by determining the ratio.

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

First, a system and method for link adaptation in an HDR scheme according to an embodiment of the present invention will be described.

7 is a diagram illustrating a data rate control information symbol and a data rate change control information symbol transmission diagram in an HDR scheme according to an embodiment of the present invention. As illustrated in FIG. 7, terminals connected to a base station to receive a data service are classified into a plurality of groups according to when data transmission rate control information (Data Rate Control) symbols are transmitted from each terminal. do. In an embodiment of the present invention, the terminals are classified into three groups, for example, A, B, and C groups. In addition, each terminal transmits a data rate control information symbol at a predetermined period through a reverse link pilot channel to request the base station the maximum data rate that can be received by the terminal. Accordingly, the terminal transmits only the change of the data rate to the base station to inform the base station of the maximum receivable data rate corresponding to the changed reception signal state even when the data rate control information symbol is not transmitted. In order for the terminal to transmit the change of the data rate to the base station, the terminal requests a command to increase the data rate, a command to lower the data rate, and a command to maintain the data rate through a Rate Up Down (RUD) symbol. Since the data rate change control information symbol is composed of 2 bits, the influence of interference can be reduced more than 4 bits of the data rate control information symbol.

RUD symbol action 00 Bitrate rise 01 Maintain bitrate 11 Rate drop 10 Do not use

Table 2 shows a method of generating a data rate change control information symbol for the terminal to transmit a change in data rate to the base station. The data rate change control information symbol is generated as the data rate shown in Table 1 changes. The base station receives a data rate change control information symbol having less influence of interference than the data rate control information symbol. Thus, when the base station detects a reception signal of terminals connected to receive data service, the influence of interference is minimized, and as the influence of the interference is reduced, the number of terminals that can be connected to the base station for data service increases. It is done.

Here, the reverse link transmission apparatus of the terminal for transmitting the data rate control information symbol will be described with reference to FIG.

8 is a diagram illustrating an apparatus for transmitting a data rate control information symbol and a data rate change control information symbol according to an embodiment of the present invention. The channel configuring the reverse link includes a pilot channel, a medium rate channel (MAC) channel for transmitting a reverse rate indicator (RRI) symbol, a data rate control information symbol, and a data rate change control information symbol, and a traffic ( There is a traffic channel for transmitting a traffic packet and a control packet. Each of the channels is modulated into a transmission signal through a respective transmission device. The pilot channel transmitter 711 transmits the pilot channel, the RRI channel transmitter 712 transmits the RRI symbol, and transmits the data rate control information channel. Device 713 is the data rate control information symbol, traffic / control (Traffic / Control) channel transmitter 715 is the traffic and control information, data rate change control information channel transmitter 717 is the data rate The change control information symbol is modulated into a transmission signal.

The signal output from the pilot channel transmitter 711 and the RRI channel transmitter 712 is output to a time division multiplexer (MUX) 714, and the data rate control information channel transmitter 713 is changed. The signal output from the control information channel transmitter 717 is output to the switch 718. The signal output from the traffic / control channel transmitter 715 is output to the complex spreader 716. The switch 718 switches the transmission time points of the data rate control information symbol and the data rate change control information symbol to the time division multiplexer 714. The time division multiplexer 714 time division multiplexes the signals output from the pilot channel transmitter 711, the RRI channel transmitter 712, and the switch 718 and outputs them to the complex spreader 716. The complex spreader 716 complexly spreads the time division multiplexed signal by the time division multiplexer 714 and the output signal of the traffic / control channel transmitter 715 and transmits the complex spreader.

A transmission time of the data rate control information symbol and the data rate change control information symbol according to the operation of the switch 718 will be described with reference to FIG. 9. The switch 718 determines the input signal of the time division multiplexer 714 by switching ON the output of the data rate control information channel transmitter 713 at the time of transmission of the previously determined data rate control information symbol. At the time of transmission of the data rate change control information symbol that has already been determined, switching off the output of the data rate control information channel transmitter 713 and switching to the output of the data rate change control information channel transmitter 717. The signal is turned on to determine the input signal of the time division multiplexer 714.

Meanwhile, an apparatus for generating the transmitted data rate change control information symbol will be described with reference to FIG. 10. When the received signal-to-interference ratio of the forward link estimated by the terminal through the forward link pilot channel is input to the data rate mapping apparatus 1311, the data rate mapping apparatus 1311 may determine the received forward link. The received signal-to-interference ratio is mapped to the data rate and output to the data rate control information mapping device 1312. The data rate control information symbol mapping apparatus 1312 maps the data rate output from the data rate mapping apparatus 1311 to data rate control information symbols and outputs the data rate control information symbol mapping apparatus 1312. The data rate control information symbol is outputted to the data rate control information channel transmitter 713 of FIG. The buffer Z- ¹ 1313 stores the data rate output from the data rate mapping device 1311 and outputs the data rate at a previous point in time of the input data rate. The subtractor 1314 calculates the difference between the data rate at the present time, that is, the data rate at the present time and the data rate at the previous time, which is the output of the buffer 1313. To the data rate change control information symbol mapping apparatus 1315. The data rate change control information symbol mapping apparatus 1315 maps the difference between the data rate of the previous time point outputted by the subtractor 1314 and the data rate of the current time point to the data rate change control information symbol. The data rate change control information symbol output from the data rate change control information symbol mapping apparatus 1315 is output to the data rate change control information channel transmitter 717 of FIG. 8.

As described with reference to FIG. 10, when the terminal transmits the data rate control information symbol and the data rate change control information symbol through a reverse link pilot channel, the base station transmits the data rate control information symbol and the data rate change control information symbol transmitted from the terminal. This is received and detected. The apparatus for detecting a base station data rate change control information symbol will be described with reference to FIG. 11. First, as described with reference to FIG. 9, when the terminal transmits a data rate control information symbol, the base station receives a signal, and the received signal is input to a data rate control information detector 1511. The data rate control information detector 1511 detects the data rate control information symbol by inputting the received signal and outputs the detected data rate control information symbol to the data rate mapping device 1512. The data rate mapping apparatus 1512 inputs a data rate control information symbol output from the data rate control information detector 1511, maps the data rate control information symbol to a data rate, and outputs it to the switch 1514. The switch 1514 operates in the same manner as the switch 718 described with reference to FIG. 8. That is, when the data rate control information symbol is transmitted, the switch 1514 determines the data rate, which is the output of the data rate mapping apparatus 1512, as an input signal of the buffer 1515, and the data rate change control information symbol is determined. At the time of transmission, the previously determined data rate is determined as an input signal of the buffer 1515. The switch 718 determines the input signal of the time division multiplexer 714 by switching ON the output of the data rate control information channel transmitter 713 at the time of transmission of the previously determined data rate control information symbol. At the time of transmission of the data rate change control information symbol that has already been determined, switching off the output of the data rate control information channel transmitter 713 and switching to the output of the data rate change control information channel transmitter 717. The signal is turned on to determine the input signal of the time division multiplexer 714.

Meanwhile, as described with reference to FIG. 9, when the terminal transmits a data rate change control information symbol, the base station receives a signal, and the received signal is input to a data rate change control information detector (RUD Detector) 1513. The data rate change control information detector 1513 receives the received signal, detects a data rate change control information symbol, and outputs the same to a data rate updater 1516. The data rate updater 1516 inputs a signal output from the buffer 1515, that is, a previous data rate and a signal output from the data rate change control information detector 1513, that is, a data rate change control information symbol. The terminal generates and outputs the maximum data rate that can be received.

Herein, an operation of a terminal for link adaptation in the HDR scheme will be described with reference to FIG. 12. 12 is a flowchart illustrating a link adaptation process of a terminal using an HDR scheme according to an embodiment of the present invention. When a call is initiated (step 1711), the terminal detects a data rate control information symbol received through a forward link pilot channel. After acquiring the transmission period of the data rate control information symbol determined and transmitted by the base station (step 1713), the switch 718 of the reverse link transmitter for transmitting the data rate control information symbol described with reference to FIG. 8 is set accordingly. (Step 1715). Then, the terminal receives a signal according to the operation of the switch 718 (step 1717) and estimates a pilot reception signal-to-interference ratio from the received signal (step 1719) to determine a data rate control information symbol (step 1721). ). After determining the data rate control information symbol, it is checked whether the current time corresponds to the period of transmitting the data rate control information symbol (step 1723). If the current time corresponds to the transmission period of the data rate control information symbol, the reverse link is checked. The data rate control information symbol is transmitted through the transmitter (step 1729). If the current time point is not the transmission period of the data rate control information symbol, a data rate change control information symbol is generated (step 1725). The data rate change control information symbol is transmitted to the base station (step 1725).

The operation of the base station for link adaptation in the HDR scheme will be described with reference to FIG. 13. FIG. 13 is a flowchart illustrating an operation process of a base station for link adaptation in an HDR scheme according to an embodiment of the present invention. First, when a call is started (step 1810), the base station determines a data rate control information symbol of a terminal corresponding to the call. In step 1811, an operation method of the switch 1514 of the base station data rate change control information symbol detection apparatus shown in FIG. 11 is set (step 1813). On the other hand, when a period for transmitting the data rate control information symbol is determined as shown in Figure 7 according to when the data rate control information is transmitted to a plurality of terminals connected to receive the data service to the base station Groups can be classified. Therefore, determining the transmission period of the data rate control information symbol of a specific terminal is the same as determining which group among a plurality of groups classifying terminals connected to the base station. The transmission period of the information symbol includes the transmission start time of the data rate control information symbol, and the terminals connected to the base station are divided into a plurality of groups according to the transmission time of the data rate control information symbol. When the data rate control information symbol is transmitted once every 16 slots, the terminals connected to the base station may be classified into 16 groups. When the data rate control information symbol is transmitted once every 8 slots, the base station may be transmitted to the base station. The connected terminals can be classified into eight groups. In the embodiment of the present invention, since the HDR scheme is implemented in a structure in which 16 slots constitute one frame, it is assumed that data transmission rate control information symbols are transmitted at least once every 16 slots. The base station transmits the transmission period of the determined data rate control information symbol to the terminal (step 1815). Then, when the base station receives a signal (step 1817), the base station transmits the transmission period of the data rate control information symbol. Check if the time corresponds to (step 1819). If the time point at which the signal is received is a time corresponding to the transmission period of the data rate control information symbol, the base station detects the data rate control information symbol (step 1821) and determines a data rate requested by the terminal (step 1821). Step 1825). If the time point at which the base station receives the signal is not a time corresponding to the transmission period of the data rate control information symbol, the base station detects the data rate change control information symbol (step 1823) to determine the data rate requested by the terminal. (Step 1825).

Second, a system and method for link adaptation in a CDMA 2000 scheme according to another embodiment of the present invention will be described. In the present invention, in the CDMA 2000 method, the base station transmits the pilot signal strength measurement message in a link adaptation method that can adapt to the change of the received signal state of the terminal, and transmits the pilot signal strength measurement message through the pilot signal strength measurement message so that the base station correctly follows the changed signal status. A system and method are proposed in which a base station correctly follows a changed reception signal state by transmitting control information for increasing or decreasing a pilot received signal to interference ratio by a predetermined step. That is, in the CDMA 2000 method, the terminal transmits a pilot reception signal-to-interference ratio, which is a reception signal state of the terminal, to a base station through a pilot signal strength measurement message at a predetermined time interval, and in a time interval in which the pilot signal strength measurement message is not transmitted. The terminal transmits received signal-to-interference ratio control information (CCB: C / I Control Bit) to the base station so that the base station increases or decreases the received pilot received signal-to-interference ratio by a predetermined step according to its received signal state. Accordingly, the base station can improve the data throughput of the forward link by adapting the received signal state of the forward link of the terminal according to the changing channel even in a time interval in which the pilot signal strength measurement message is not transmitted. have.

14 is a diagram illustrating transmission of a pilot signal strength measurement message and received signal-to-interference ratio control information in a CDMA 2000 scheme according to an embodiment of the present invention.

FIG. 14 transmits a pilot signal strength measurement message 412, a pilot 413, and power control information 414, and then transmits traffic 415 during the next frame, and transmits the pilot signal strength measurement message 412. Then, while transmitting the traffic 415, the pilot and received signal-to-interference ratio control information is transmitted for each power control group 411. The number of transmissions of the power control information and the number of transmissions of the reception signal-to-interference ratio control information are already determined in a time interval after transmitting the pilot signal strength measurement message 412 and before transmitting the next pilot signal strength measurement message. Must be present FIG. 14 illustrates a case in which reception signal-to-interference ratio control information is transmitted for every power control group without transmitting power control information. The base station measures the pilot signal strength by transmitting a transmission ratio control information between terminals. The pilot received signal-to-interference ratio of the terminal received from the message 412 can be continuously updated according to the receiving channel of the terminal.

Here, a reverse link transmitter of a terminal for transmitting the pilot signal strength measurement message, power control information, and received signal-to-interference ratio control information will be described with reference to FIG. 15.

15 is a diagram illustrating an apparatus for transmitting a pilot signal strength measurement message, power control information, and received signal-to-interference ratio control information according to an embodiment of the present invention.

First, power control information and received signal-to-interference ratio control information generated in each power control group (PCG) by the terminal for power control are input to the switch 813, and according to the switching operation of the switch 813. The output is switched to the repeater 811. The switch 813 determines to switch the power control information as an input signal of the repeater 811 according to the number of times of transmission of the power control information and the received signal-to-interference ratio control information, and switches or switches the received signal-to-interference ratio. Control information is determined as an input signal of the repeater 811 and is switched. The repeater 811 repeats the signal output from the switch 810 and outputs the same to the multiplexer (MUX) 812. The multiplexer 812 multiplexes the signal repeatedly output from the iterator 811 and the pilot channel, and outputs the multiplexer 814 to the spreader 814. The pilot signal strength measurement message / traffic channel transmitter 813 modulates the generated pilot signal strength measurement message and traffic into a transmission signal and outputs the modulated signal to the spreader 814. The spreader 814 spreads and transmits a signal output from the pilot signal strength measurement message / traffic channel transmitter 813 and a signal output from the multiplexer 812.

Here, the transmission time of the pilot, the power control information, and the received signal-to-interference ratio control information according to the operation of the switch 810 will be described with reference to FIG. 16. The switch 810 should transmit the power control information corresponding to the transmission frequency of the power control information and the transmission frequency of the received signal-to-interference ratio control information which are already determined in a time period during which the pilot signal strength measurement message is not transmitted. In the power control group, the power control information is switched on to be the input signal of the repeater 811, and the power control information is switched off in a section in which the reception signal-to-interference ratio control information is transmitted. The received signal-to-interference ratio control information is switched on to be input to the repeater 811.

Meanwhile, an apparatus for generating the transmitted signal to interference ratio control information will be described with reference to FIG. 17. The pilot received signal-to-interference ratio of the forward link estimated by the terminal through the forward link pilot channel is input to the subtractor 1411, the switch 1416, and the pilot signal strength measurement message mapping device 1417. Then, the pilot signal strength measurement message mapping apparatus 1417 maps and transmits the input pilot received signal-to-interference ratio to a pilot signal strength measurement message. The subtractor 1411 inputs a pilot reception signal-to-interference ratio inputted at the current time point, and a pilot reception signal-to-interference ratio of the previous time point which is an output signal of the summer 1414, thereby piloting signal-to-interference ratio and the previous time point. The difference between the pilot received signal and the interference ratio of the calculated and outputted to the received signal to interference ratio control information mapping apparatus 1412. When the signal output from the subtractor 1411 has a positive value, the received signal-to-interference ratio control information mapping apparatus 1412 is higher than the pilot received signal-to-interference ratio at the present time. In the present invention, the received signal-to-interference ratio control information corresponding to a command for increasing the pilot received signal-to-interference ratio of the base station is mapped and outputted, and has a negative value of the signal output from the subtractor 1411, that is, When the pilot reception signal-to-interference ratio is lower than the pilot reception signal-to-interference ratio at the previous time, the reception signal-to-interference ratio control information corresponding to the command to lower the pilot reception signal-to-interference ratio of the base station is mapped and output. The switch 1416 inputs a pilot reception signal-to-interference ratio of the current time and a pilot reception signal-to-interference ratio of a previous time, which is an output signal of the summer 1414, and the pilot signal strength measurement message is transmitted when the current signal is transmitted. The pilot reception signal-to-interference ratio of the time point is output to the buffer 1415, and when the pilot signal strength measurement message is not transmitted, the reception signal-to-interference ratio of the previous time point, which is an output signal of the summer 1414, is buffered. Will output The buffer 1415 stores a signal output from the switch 1416, and the reception signal-to-interference ratio mapping apparatus 1413 controls the reception signal-to-interference ratio output from the reception signal-to-interference ratio control information mapping apparatus (! 412). Information is mapped to a received signal-to-interference ratio and output to the summer 1414, and a received signal-to-interference ratio is generated by a predetermined step according to the received signal-to-interference ratio control information transmitted from the terminal. The summer 1414 calculates a pilot reception signal-to-interference ratio at a previous time by summing the signal output from the reception signal-to-interference ratio mapping apparatus 1413 and the signal output from the buffer 1415.

Here, a base station apparatus for detecting received signal-to-interference ratio control information transmitted by the terminal will be described with reference to FIG. 18. 18 is a block diagram illustrating an apparatus for detecting received signal-to-interference ratio control information according to an embodiment of the present invention. At the time when the terminal transmits a pilot signal strength measurement message, the signal received by the base station is a pilot signal strength measurement message. It is input to a detector 1611. The pilot signal strength measurement message detector 1611 receives the pilot signal strength measurement message by inputting the received signal and outputs the pilot signal strength measurement message to the received signal-to-interference ratio mapping apparatus 1612. The received signal-to-interference ratio mapping apparatus 1612 maps the signal output from the pilot signal strength measurement message detector 1611 to the received signal-to-interference ratio and outputs it to the switch 1615. The switch 1615 switches on the received signal-to-interference ratio, which is an output signal of the received signal-to-interference ratio mapping device 1612, to the buffer 1616 at the time when the terminal transmits a pilot signal strength measurement message. When the terminal does not transmit the pilot signal strength measurement message, the terminal switches on the received signal-to-interference ratio calculated at the previous time point to become an input signal of the buffer 1616. On the other hand, in a time interval in which the terminal does not transmit the pilot signal strength measurement message, the signal received by the base station is input to the received signal-to-interference ratio control information detector 1613. The received signal-to-interference ratio control information detector 1613 detects the received signal-to-interference ratio control information by inputting the received signal and outputs the received signal-to-interference ratio control information to the received signal-to-interference ratio mapping apparatus 1614. . The received signal-to-interference ratio mapping apparatus 1614 maps the received signal-to-interference ratio control information output from the received signal-to-interference ratio control information detector 1613 to a received signal-to-interference ratio and outputs it to the summer 1615. The adder 1617 adds the received signal-to-interference ratio stored in the buffer 1616 and the received signal-to-interference ratio, which is an output signal of the received signal-to-interference ratio mapping apparatus 1614, to experience the pilot at the present time. Calculate and output the received signal-to-interference ratio.

Herein, an operation of a terminal for link adaptation in the CDMA 2000 scheme will be described with reference to FIG. 19. 19 is a flowchart illustrating a link adaptation process of a terminal using a CDMA 2000 method according to an embodiment of the present invention. When a call is initiated (step 1910), the terminal receives received signal-to-interference ratio control information received through a forward link pilot channel. After the symbol is detected and the transmission period of the received signal-to-interference ratio control information symbol determined and transmitted by the base station is acquired (step 1911), the reverse link transmitter for transmitting the received signal-to-interference ratio control information symbol described with reference to FIG. Set the switch 813 (step 1913). Then, the terminal receives a signal according to the operation of the switch 813 (step 1915) and estimates a pilot received signal-to-interference ratio from the received signal (step 1917). Generate a pilot signal strength measurement message. After generating the pilot signal strength measurement message, it is checked whether the current time corresponds to the period of transmitting the pilot signal strength measurement message (step 1919). If the current time corresponds to the transmission period of the pilot signal strength measurement message, the reverse direction is performed. The pilot signal strength measurement message is transmitted through the link transmission apparatus (step 1921). If the current time point is not the transmission period of the pilot signal strength measurement message symbol, the received signal-to-interference ratio control information symbol is generated (step 1923). In step 1925, the received signal-to-interference ratio control information symbol is transmitted to a base station.

The operation of the base station for link adaptation in the CDMA 2000 scheme will be described with reference to FIG. 20. 20 is a flowchart illustrating an operation of a base station for link adaptation in an HDR scheme according to an embodiment of the present invention. When a call is started (step 2111), the base station determines a transmission period of a reception signal to interference ratio control information symbol to be transmitted by a terminal. Determine (step 2113). In order to determine the transmission period of the received signal-to-interference ratio control information symbol, it is necessary to find a transmission period that satisfies both the forward power control through the power control information and the link adaptation through the received signal-to-interference ratio control information. If the transmission period of the interference ratio control information symbol is short, the link adaptation performance is improved, but the forward power control performance is decreased. If the transmission period of the received signal to interference ratio control information symbol is longer, the forward power control performance is maintained, but the link adaptation performance is improved. Will fall. Therefore, the base station determines the transmission period of the received signal-to-interference ratio control information symbol in consideration of both link adaptation performance and forward power control performance. When the transmission period of the received signal-to-interference ratio control information symbol is determined (step 2115) after setting the operation of the switch 1615 shown in FIG. 18, the base station transmits the determined pilot signal strength measurement message transmission period to the terminal. If the signal is received (step 2117), the base station determines whether it is a time corresponding to the transmission period of the pilot signal strength measurement message when receiving the signal (step 2119). If the time point at which the signal is received is a time corresponding to the transmission period of the pilot signal strength measurement message, the base station detects a pilot signal strength measurement message (step 2223) and determines a pilot reception signal-to-interference ratio of the terminal. (Step 2227). If the time point at which the base station receives the signal is not the time corresponding to the transmission period of the pilot signal strength measurement message, the base station detects the received signal-to-interference ratio control information symbol (step 2225) and adjusts the pilot received signal-to-interference ratio of the terminal. It is determined (step 2227).

As described above, the present invention transmits a data rate control information symbol in the HDR method, and requests a maximum data rate that can be received by the terminal itself, and then changes the state of a received signal received by the terminal through the data rate control information symbol. Only the change in the maximum data rate transmitted is reported via the data rate change control information symbol, thereby minimizing the interference effect of the base station received signal, thereby increasing the number of terminals that the base station can provide data service and at the same time, the base station data service It has the advantage of improving capacity.

In addition, in the CDMA 2000 method, the pilot signal strength measurement message is transmitted to report the pilot signal strength of the terminal, and the state of the received signal received by the terminal is changed to the pilot signal strength transmitted through the pilot signal strength measurement message. By transmitting control information that increases or decreases by a certain step, the base station continuously monitors the changing reception signal state of the terminal to enable the link adaptation to the rapidly changing terminal reception signal state, thereby improving the data throughput of the forward link. It has the advantage of improving the data service providing environment.

Claims (28)

In a link adaptation system of a code division multiple access system, An apparatus for transmitting a data rate control information channel for determining data rate according to a signal state received through a forward link pilot channel of a terminal and generating and transmitting data rate control information to a base station; And a data rate change control information channel transmitter configured to generate data rate change control information and transmit the data rate change control information to the base station after the data rate control information is transmitted, having a difference between the data rate of the current slot and the data rate of the previous slot. A link adaptation system of a code division multiple access system. The method of claim 1, The data rate change control information indicates information for controlling to increase, decrease, or maintain the receivable data rate of the terminal itself transmitted from the terminal. The method of claim 1, The terminal belongs to one of a plurality of groups that classify terminals providing data services in the base station, and the start time for transmitting data rate control information is different according to the group to which the terminal belongs. Link adaptation system of a split multiple access system. The method of claim 3, In a slot in which a terminal belonging to a specific group of the plurality of groups transmits the data rate control information, a terminal belonging to groups except for the specific group transmits the data rate change control information. Link adaptation system. In a link adaptation system of a code division multiple access system, A data rate control information receiver for detecting data rate control information in a specific slot of a received signal and detecting the detected data rate control information as a data rate; A data rate change control information receiver configured to detect data rate change control information by detecting data rate change control information in a slot after the specific slot after detecting the data rate; And a data rate updater configured to control the detected data rate according to the data rate change control information and determine a data rate of the terminal. The method of claim 5, The data rate change control information indicates information for controlling to increase, decrease, or maintain the receivable data rate of the terminal itself transmitted from the terminal. The method of claim 5, And the system divides terminals providing data services into a plurality of groups so as to be different from each other according to a time point at which the data rate control information is transmitted. The method of claim 7, wherein Terminals belonging to each of the plurality of groups transmit a data rate change control information to terminals belonging to groups except the specific group in a slot in which a terminal belonging to a specific group of the plurality of groups transmits the data rate control information. Link adaptation system of a code division multiple access system, characterized in that the control to control. In the link adaptation method of a code division multiple access system, Determining a transmission rate using a signal received from a base station; Generating rate control information corresponding to the transmission rate and transmitting the same to the base station; A link adaptation method of a code division multiple access system, comprising: calculating a difference between a data rate of a current slot and a data rate of a previous slot, generating data rate change information corresponding to the difference value, and transmitting the same to the base station; The method of claim 9, The rate control information is a link adaptation method of a code division multiple access system, characterized in that the information to control to increase, decrease or maintain the receivable data rate of the terminal itself transmitted from the terminal. The method of claim 9, The terminal belongs to one of a plurality of groups that classify terminals providing data services in the base station, and code division is characterized in that start points for transmitting rate control information are different according to the group to which the terminal belongs. Link adaptation method of multiple access system. The method of claim 11, In a slot in which a terminal belonging to a specific group of the plurality of groups transmits the rate control information, the terminals belonging to groups except for the specific group transmit the data rate change information. Adaptation method. In the link adaptation method of a code division multiple access system, Determining the data transmission rate control information transmission period and receiving the signal after transmitting to the terminal, and when the time point of receiving the signal is a data transmission rate control information transmission slot, the data rate control information is detected to determine the receivable data rate of the terminal. Detecting process, Detecting data rate change control information by detecting data rate change control information when the time point at which the signal is received is a data rate change control information transmission slot; And updating the receivable data rate of the terminal and transmitting the received data rate to the terminal according to the detected data rate change control information. The method of claim 13, The data rate change control information indicates information for controlling to increase, decrease or maintain the receivable data rate of the terminal itself. The method of claim 13, Determining the data transmission rate control information transmission period; Code division, characterized in that the terminal is divided into a plurality of groups to receive a data service, and then to be different from the start time for transmitting data rate control information of the terminals belonging to the plurality of groups Link adaptation method of multiple access system. The method of claim 15, Terminals belonging to each of the plurality of groups transmit a data rate change control information to terminals belonging to groups except the specific group in a slot in which a terminal belonging to a specific group of the plurality of groups transmits the data rate control information. Link adaptation method of a code division multiple access system, characterized in that the control. In a link adaptation system of a code division multiple access system, After acquiring the received signal-to-interference ratio transmission period designating the slot for transmitting the pilot signal strength measurement message and the received signal-to-interference ratio control information symbol from the base station, the received signal-to-interference ratio of the received pilot signal is detected and modulated into a pilot signal strength measurement message. A pilot signal strength measurement message channel transmitter for transmitting; Received signal-to-interference ratio for transmitting the received signal-to-interference ratio control information by mapping the difference between the pilot received signal-to-interference ratio and the detected pilot received signal-to-interference ratio before the received signal in the slot after transmitting the pilot signal strength measurement message A link adaptation system of a code division multiple access system, characterized by comprising a control information channel transmitter. The method of claim 17, If the detected pilot received signal-to-interference ratio is higher than the previous pilot received signal-to-interference ratio, the received signal-to-interference ratio control information is mapped to increase the pilot received signal-to-interference ratio to the base station. Link adaptation system. The method of claim 17, In the code division multiple access system, the received signal-to-interference ratio control information is mapped to reduce the pilot signal-to-interference ratio to the base station when the detected pilot signal-to-interference ratio is lower than a previous pilot signal-to-interference ratio. Link adaptation system. The method of claim 17, And when the detected pilot received signal to interference ratio is equal to the previous pilot received signal to interference ratio, the base station maps the received signal to interference ratio control information to maintain the pilot received signal to interference ratio. Adaptive system. In a link adaptation system of a code division multiple access system, A pilot signal strength measurement message receiver which detects a pilot signal strength measurement message in a specific slot of a signal received from a terminal and maps the detected pilot signal strength measurement message to a reception signal to interference ratio; A received signal-to-interference ratio control information receiver which detects the received signal-to-interference ratio control information in the next slot of the specific slot and maps the received signal-to-interference ratio to output; Code division multiplexing, comprising: an adder for determining the pilot received signal-to-interference ratio experienced by the terminal by adding the received signal-to-interference ratio of the pilot signal strength measurement message and the received signal-to-interference ratio of the received signal-to-interference ratio control information Link adaptation system of connection system. The method of claim 21, The received signal-to-interference ratio control information indicates information for controlling to increase, decrease or maintain the received signal-to-interference ratio according to the signal reception state of the terminal. In the link adaptation method of a code division multiple access system, Generating a pilot signal strength measurement message by estimating a pilot signal strength ratio of a received signal after acquiring a received signal-to-interference ratio transmission period specifying a slot for transmitting a pilot signal strength measurement message and a received signal-to-interference ratio control information symbol from a base station; Process, Transmitting the generated pilot signal strength measurement message to the base station in a pilot signal strength measurement message transmission interval; And transmitting the pilot signal strength measurement message to a base station by mapping the received signal-to-interference ratio control information with a difference between the previous pilot received signal-to-interference ratio and the detected received signal-to-interference ratio and transmitting the signal to the base station. Link adaptation method for split multiple access system. The method of claim 23, wherein If the detected pilot received signal-to-interference ratio is higher than the previous pilot received signal-to-interference ratio, the received signal-to-interference ratio control information is mapped to increase the pilot received signal-to-interference ratio to the base station. Link adaptation method. The method of claim 24, In the code division multiple access system, the received signal-to-interference ratio control information is mapped to reduce the pilot signal-to-interference ratio to the base station when the detected pilot signal-to-interference ratio is lower than a previous pilot signal-to-interference ratio. Link adaptation method. The method of claim 24, And when the detected pilot received signal to interference ratio is equal to the previous pilot received signal to interference ratio, the base station maps the received signal to interference ratio control information to maintain the pilot received signal to interference ratio. Adaptation method. In the link adaptation method of a code division multiple access system, Receives a signal after transmitting the signal to interference ratio control information transmission period and transmits it to the terminal, and detects the pilot signal strength measurement message from the received signal when the signal reception time is a pilot signal strength measurement message transmission interval. Mapping to a pilot received signal-to-interference ratio; Detecting a received signal-to-interference ratio control information symbol from the received signal and mapping the received signal-to-interference ratio control information symbol to the pilot received signal-to-interference ratio when the time point at which the signal is received is a reception signal-to-interference ratio control information transmission interval; Code division multiple access, comprising: determining a pilot received signal to interference ratio of the terminal by adding the received signal to interference ratio of the detected pilot signal strength measurement message and the received signal to interference ratio of the received signal to interference ratio control information; Link adaptation method of system. The method of claim 27, The received signal-to-interference ratio control information indicates information for controlling to increase, decrease, or maintain the received signal-to-interference ratio according to the signal reception state of the terminal.

Images