KR20000011799A - Method and system form processing packet data in mobile communication system - Google Patents

Abstract

PURPOSE: A packet data processing device for mobile communication system and the method thereof are provided to maximize the data throughput in the packet service by transmitting data in prior order according to the channel status and service quality in hand-off. CONSTITUTION: The packet data processing device for mobile communication system comprises: a channel status information receiver(203) receiving channel status information related to forward channels from plural mobile stations; a supplemental channel transmission controller(205) deciding the data transmission ratio of said respective mobile station by said channel status information; and a supplemental channel transmitter(209) transmitting the data to be transmitted to said mobile station in said decided data transmission ratio.

Description

Packet data processing system and method of mobile communication system {METHOD AND SYSTEM FORM PROCESSING PACKET DATA IN MOBILE COMMUNICATION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data processing method of a mobile communication system, and more particularly, to a method of processing data by differently allocating power and data rates according to a channel state and a quality of service state between a base station and a mobile station.

In general, IS-95 services voice data requiring real time. The voice data service is called a circuit service. The circuit service continuously transmits incoming circuit data. A mobile communication system such as IMT-2000 supports a high data rate and provides a packet data service through an additional channel of data having a large amount of data such as video and video. While the circuit service provides continuous voice data, in the case of packet data, the data is discontinuously bursty. In addition, in the case of a voice service, the same service without delay should be provided to all users regardless of channel conditions, whereas in the case of a data service, the purpose of maximizing the overall throughput is to satisfy different data transmission requirements for each user. To meet these requirements, voice services require more power for mobile stations with poor channel conditions, while data services do not maximize data throughput in the same way.

When the data processing method of the circuit service that processes and transmits data continuously as described above is applied to the packet service that serves the data discontinuously, the data processing efficiency decreases and the channel efficiency decreases because the transmission rate of packet data is not maximized. There was this.

The same problem also occurs at handoff. In other words, in the existing mobile communication system providing a circuit service, a handoff method uses a method of combining or selecting the same data transmitted simultaneously from two or more base stations involved in the handoff. If this is to be applied to a packet service, there is a problem that packet throughput is lowered because the data rate cannot be maximized adaptively depending on the channel condition. Therefore, in order to provide packet data service, the data transmission and handoff method must be redesigned to meet the packet data transmission characteristics. In particular, there is a need for a method for forward power allocation to mobile stations at a base station and for data path establishment via the base station.

Accordingly, an object of the present invention is to estimate the state of a corresponding channel from a base station signal transmitted from a base station during packet data communication of a mobile communication system, and transmit channel state information to a base station, and the base station receives the channel state information to receive a channel state. The present invention provides a data processing method for packet data communication in which data is transmitted by allocating high power to a good mobile station.

It is still another object of the present invention to transmit channel state information to a base station by estimating a state of a corresponding channel from a base station signal transmitted from a base station in packet data communication of a mobile communication system, and the base station receives the channel state information to receive a channel The present invention provides a data processing method for packet data communication that transmits data at a high data rate to a mobile station in good condition.

It is still another object of the present invention to transmit a channel state information to a base station, and in response to the packet data communication from the base station to receive data including a data rate indicator indicating the data rate information to respond quickly to the variable data rate It provides a data processing method.

It is still another object of the present invention to provide a data processing method for packet data communication in which the packet data is transmitted by determining the data rate and power based on a weight according to the type of data being serviced by the mobile station in packet data communication of the mobile communication system. Is in.

It is another object of the present invention to transmit different data to a base station associated with a handoff to maximize the throughput of packet data during handoff of a mobile communication system, and the base station receives channel state information and receives channel state information. The present invention provides a data processing method for packet data communication in which packet data is transmitted to a mobile station only when good is.

Another object of the present invention is to transmit the same data to the base station associated with the handoff in order to maximize the throughput of the packet data during handoff of the mobile communication system, the base station receives the channel state information to receive the channel state information The present invention provides a data processing method for packet data communication in which packet data is transmitted to a mobile station only in a good case.

In order to achieve the above object, the present invention provides a method of maximizing data throughput in a packet service of a mobile communication system, comprising a network, a base station controller, a base station, and a mobile station, wherein the base station controller when data is provided to the mobile station occurs. Receiving the data through the network and transmitting the data to at least two base stations related to the handoff of the mobile station during handoff; and each base station receiving data from the base station controller Determining a data rate to the mobile station according to the channel state information periodically reported by the mobile station, and when the data rate is determined, transmitting the data to the mobile station; and the mobile station transmits the base station through the forward channel from the base station. Receive and cycle the signal In a report from the signal to each of the base station the channel state for the forward channel, and then, characterized by a third constituted by any method comprising the steps of: receiving data from the respective base stations.

1 is a diagram showing a system configuration applied at the time of handoff according to an embodiment of the present invention.

2 is a diagram illustrating a packet data receiving process according to a channel state report of a mobile station according to an exemplary embodiment of the present invention.

3 is a diagram showing a structure of a base station channel card according to the present invention;

4 is a diagram illustrating a handoff method for sending different data to two base stations according to the first embodiment of the present invention.

5 illustrates a finger structure of a mobile station for receiving two different data according to an embodiment of the present invention.

6 is a diagram illustrating a channel state report during handoff according to an embodiment of the present invention.

7 is a flowchart illustrating a handoff method according to different data transmissions to two or more base stations according to an embodiment of the present invention.

8 is a diagram illustrating a data buffer of two base stations when different data is transmitted to two base stations according to an embodiment of the present invention.

9 is a diagram illustrating data relay to one base station when one base station is congested according to an exemplary embodiment of the present invention.

10 is a diagram illustrating preliminary data transmission between base stations in preparation for congestion of one base station according to an exemplary embodiment of the present invention.

11 is a diagram illustrating a system in which the base station controller transmits the same data to two base stations and performs handoff according to an embodiment of the present invention.

12 illustrates a structure of a reverse channel power control frame for forward channel reporting according to an embodiment of the present invention.

13 is a diagram illustrating a base station buffer when sending the same data to two base stations according to an embodiment of the present invention.

14 is a view illustrating a data transmission position check according to an embodiment of the present invention.

15 is a flowchart of a handoff method for sending identical data to two or more base stations according to an embodiment of the present invention.

FIG. 16 is a flowchart illustrating a first method for transmitting unsuccessful data when data transmission of one of two base stations fails in an embodiment of the present invention. FIG.

FIG. 17 is a flowchart illustrating a second method for transmitting unsuccessful data when data transmission of one of two base stations fails in an embodiment of the present invention. FIG.

18A, 18B, and 18C are flowcharts illustrating operations of the base station controller, the base station, and the mobile station with respect to FIG.

19A illustrates a data frame including a rate indication on an additional channel for transmitting user data according to an embodiment of the present invention.

19B illustrates inserting and transmitting a rate indication through a separate channel according to an embodiment of the present invention.

20 illustrates the structure of a base station and a mobile station for performing efficient forward packet transmission in accordance with the present invention.

21 is a flowchart illustrating an operation of a base station for transmitting by inserting a rate indicator in the data according to the present invention.

22 is a flowchart of the operation of a mobile station according to the present invention;

23 is a diagram showing a channel state reporting process of a mobile station.

24 is a diagram illustrating a rate determining process of a base station.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on 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.

In order to maximize the throughput of packet data, the present invention receives a base station signal received from a base station, detects a channel state with the base station from the base station signal, and transmits channel state information about the same to the base station. The base station receives the channel state information from a plurality of mobile stations, respectively, and transmits packet data with a difference in data rate according to the channel state. This will be described in detail with reference to FIG. 2.

2 is a diagram illustrating that a mobile station reports a forward channel state to a base station in packet service. The forward channel may be a pilot channel or a traffic channel. The pilot channel is a common channel through which a base station transmits a pilot signal to a mobile station, and enables the mobile station to continuously monitor the channel state. The mobile station measures the power of the pilot channel or traffic channel to generate channel state information.

The channel state information may take various forms according to a measurement target channel, a channel measurement method, a measurement method encoding method, the number of information bits, and the like. In addition, the method of transmitting channel state information from the mobile station to the base station may take various forms. The present invention presents some specific embodiments thereof.

For example, the channel state information may be channel state information bits generated by detecting power of the pilot channel or a change in the pilot channel. A method of generating the channel state information bit will be described later in detail.

As another example, the channel state information may be a power control bit. The mobile station can generate a power control bit by measuring the power or pilot channel power of the traffic channel. For a method for generating a power control bit in a mobile station based on pilot power measurement, refer to the previously applied application No. 98-22219. The mobile station may send a power control bit for channel status reporting on the reverse pilot channel.

For fast adaptation to channel conditions, the frame length uses frames shorter than frames for general circuit services (20ms or 5ms) (e.g. 1.25ms or 2.5ms). In particular, an additional channel for transmitting high data rate packet data may use a 1.25ms long frame. In addition, information transmission for channel status reporting sends or equivalently sends several bits representing multiple levels for 1.25 ms to send more information than one (800 Hz) bit (power control bit) per 1.25 ms. You can use a method that sends individual bits at a faster rate. In other words, the channel status information is transmitted through the reverse channel at a transmission rate of 9.6 Kbps, 4.8 Kbps, 2.4 Kbps, or 1.2 Kbps apart from the existing 800 Hz power control bit. The reverse channel for sending the channel status information may be a reverse dedicated control channel or a separate channel status report channel. The separate channel status report channel may be a separate Walsh code channel. The channel state report channel is preferably sent without channel encoding for quick application of channel state information. For example, when sending bits representing multiple levels at 4.8 Kbps, six bits of information can be sent per 1.25 ms, so that the channel status can be reported at 64 levels more accurate than the existing 2 levels. In addition, when sending individual bits representing ± 1 at 4.8Kbps, the channel status can be updated every 0.208ms, which is less than 1.25ms, to update the value indicating the channel status. Various coding schemes may be applied to efficiently use bits representing channel state information in sending channel state information at a high data rate for channel state reporting.

As a method of generating the channel state information, a method of expressing the measured strength of the forward common pilot as a cumulative value of a predetermined number N of channel state information bits and a weighted value in the sum of? Can be. That is, if T (i) is the difference between the pilot measurement value and the measurement reference value at present (time I), T (i) may be expressed as Equation 1 below. ② The measurement reference value is a value of channel state information (CSB) to be determined at the present time.

Where CSB (j) is a channel state information bit at time j and a represents a constant greater than or equal to zero. Therefore, to generate a new channel state information bit CSB (i), the sum T (i + 1) of the previous N channel state information bits, including the new channel state information bit CSB (i), is added to the measured value of the common pilot strength. Determine the new channel state information bit CSB (i) to be close to +1 or -1, where ea (ij) is the term representing the weight in the sum of the past channel information bits. Are added with attenuated weights. If a is zero, all channel information bits are added with the same weight. As described above, when the mobile station generates the channel information bits and transmits the channel information bits to the base station as a channel state report, the base station accumulates the received channel state information bits as shown in Equation 1 to determine the channel state. Such a method of displaying channel state information has an advantage in that even if an error occurs in the channel state information bit, the error is not accumulated continuously and is restored to a normal state when a predetermined number of channel information bits pass.

Another method of displaying channel state information may be an adaptive differential pulse code modulation (ADPCM) technique. Since this method is disclosed as a method of encoding a difference between a sample value and an actual sample value adaptively predicted from previous samples, a detailed description thereof will be omitted.

In addition, the DM (Delta Modulation) technique can be used as a simpler method of displaying channel state information. This method encodes the difference between the sample value predicted from the previous samples and the actual sample value in one bit. Since this method is also a publicly disclosed technique, detailed description thereof will be omitted.

For fast adaptation to the channel condition, the frame length uses 1.25 ms as described above. However, the length of the frame can be taken differently according to the data rate. For example, you can use 20 ms frames for relatively low data rates (eg 9.6 Kbps), 5 ms frames for intermediate data rates (eg 38.4 Kbps), and 1.25 ms frames for relatively high data rates (eg 307.2 Kbps). have. Table 1 shows the number of bits per frame according to the data rate (units of Kbps) and the frame length (units of ms). The underlined items in Table 1 show an example of the combinations of supported data rates and frame lengths.

Kbps 20 ms 5 ms 1.25 ms 9.6 192 48 12 19.2 384 96 24 38.4 768 192 48 76.8 1536 384 96 153.6 3072 768 192 307.2 6144 1536 384

Hereinafter, a method of operating each base station will be described with reference to FIG. 2 prior to the description of the handoff method involving two or more base stations. Since each base station performs the same operation, only base station 105 of FIG. 1 will be described.

In order to maximize the throughput of packet data in transmitting data to the serving mobile stations 109 and 111, the base station 105 checks the status of the corresponding forward channel from the mobile stations 109 and 111 as shown in FIG. See and receive The base station must determine the power allocation and data rate according to the channel status to the mobile station forming the link with itself. The following describes a method for a base station to determine power allocation and data rate for each mobile station. There may be three methods for determining the power allocation and data rate.

In the first method, the base station 105 receiving the status report of the corresponding forward channel (Fwd Ch) transmits the transmission power of the base station 105 to the mobile station which can obtain the highest data rate with the best channel state, that is, the smallest power, during the next frame. Focus. For example, in FIG. 2, if the channel state of the mobile station 109 is good, the base station 105 concentrates the transmission power on the data transmitted to the mobile station 109 and transmits it to the supplemental channel.

Referring again to the first method, the base station 105 reports the channel status from the mobile stations 109 and 111 and calculates a power value for transmitting data at 1 Kbps for each mobile station 109 and 111 therefrom. The power value for sending data at 1 Kbps may be obtained by accumulating power control bits from the mobile station reporting the channel state. Here, the total transmit power of the base station 105 is equal to the sum of the data rates for each mobile station 109, 111 and the power value for sending data to each mobile station 109, 111 at 1 Kbps for all mobile stations 109, 111. Under these conditions, base station 105 allocates power to maximize the sum of data rates to each mobile station 109, 111. In this way, allocating the transmit power of the base station 105 to the mobile stations 109 and 111 results in allocating all the power to the mobile station 109 having the best channel condition, i.e., the power value for sending data at 1 Kbps is the minimum. This power allocation is made new every frame. In other words, the total transmit power of the base station is PT = P1 + P2 +. + PN (where P, P2, .., PN are the power to mobile station 1, mobile station 2, ..., mobile station N, respectively). When the target is the sum of the bit rates for each mobile station BR (1) + BR (2) +. We find the vector P = {P1, P2,., PN} that maximizes + BR (N). PbR (i), the power (or Eb / No) required to send data at 1 Kbps, is the value known to the base station for each link. At this time, maximizing throughput from the viewpoint of each base station can be obtained by Equation 2 below.

Given

The general solution of Equation (2) is to assign Pk = PT for k, i, the value of PbR (i), and to Pi (≠ k) = 0 for the remaining i values. If the data rate BR (k) satisfying the given condition BR (k) · PbR (k) = PT exceeds the maximum allowable data rate BRmax, then the power Pk to the mobile station where the value of PbR (i) is minimum is BRmax. PbR (k), i.e., the data rate is BRmax, and the remaining power PT-Pk is allocated to the mobile station with the next smaller PbR (i) value.

However, when the power of the base station is allocated only by the channel state, the data rate to the mobile station 109 having a good channel state will be improved, but the mobile station 111 having a poor channel state will have a poor data rate.

In the second method for solving this problem, the base station allocates power such that the transmission rate obtained by multiplying the transmission rate according to the channel state by the weighting factor w (i) according to the service characteristics of the mobile station is maximized. The weight is determined according to the quality of service (QoS) required by each mobile station in order to make a difference according to the service characteristics of the mobile station. This can be optimized by Equation 3 below.

Given

The base station allocates power according to this maximization equation and then transmits data at a corresponding rate BR (i) (BR (i) = Pi / PbR (i)) that can be sent using the power allocated for mobile station i.

In the third method, the base station 105 allocates a fixed power to each mobile station and sets the data rate variably according to the channel state monitored in real time. The base station 105 receiving the status report of the forward channel (Fwd Ch) transmits data through the additional channel at a low data rate to the mobile station having a good channel condition at a high data rate for the next mobile station during the next frame. For example, in FIG. 2, if the channel state of the mobile station 109 is good, the base station 105 transmits data to the mobile station 109 at a higher data rate, and transmits data to the mobile station 111 having a lower channel state than the mobile station 109 at a lower data rate.

Again, in the power allocation and data rate determination method according to the third method, the base station allocates fixed power to each mobile station. For example, allocating the same power to each mobile station. The base station 105 reports the channel status from the mobile stations 109 and 111 and calculates a data rate to be sent for each mobile station 109 and 111 therefrom. For example, the data rate may be determined based on a cumulative value of the power control bits from the mobile station reporting the channel state and a fixed power allocated to the mobile station. That is, as a specific example, the data rate may be determined to be proportional to the allocated fixed power and inversely proportional to the power control bit accumulation value. Since the power control bit accumulation value is updated every frame according to the channel state, the data rate is also updated according to the channel state every frame.

In the base station specifically determining the transmission rate, the fixed power allocated to the target mobile station and channel state information obtained from the target mobile station are used. The channel state information may be common pilot strength. If the transmission rate is a liquid level transmission rate, it may be expressed as Equation 4 below.

Face Rate = K · Power · Common Pilot Strength

(Where K is a constant)

(The common pilot strength is inversely proportional to the cumulative power control bit value.)

As described above, when transmitting data for one frame to the mobile station according to the power allocated by the base station, the data rate is adaptively determined according to the channel environment.

If the data rate is adaptively determined as described above, the mobile station should detect the variable data rate and receive the data. The following two methods can be used as the data rate detection method of such a mobile station.

First, the mobile station may perform blind detection to receive data of variable rate. One way for the mobile station to perform blind detection is to perform data detection for all possible data rates and then select the data of the rate that fits the Cyclic Redundancy Code (CRC).

Second, the base station may use a method of sending information on the data rate to the mobile station on the forward channel. The base station may send a rate indication on a supplemental channel for transmitting user data as shown in FIG. 19A to inform the mobile station of the rate information. The rate indication may be several rate indication bits inserted at a given position in the data frame. In this case, the rate indication bits may be transmitted at a fixed size interval (rate) and may be distributedly distributed within a frame to obtain a time diversity effect. In more detail, the base station inserts and indicates bits representing a data rate into data in a frame unit transmitted through an additional channel. It is necessary to have a means for generating a rate indicator and a means for inserting the generated rate indicator to insert the rate indicator in units of frames.

As an example, the means for generating the rate indicator may generate the rate indicator by the following method.

The base station may include Walsh code information corresponding to the transmission rate in the transmission rate indication transmitted to the mobile station. The Walsh code is a code for distinguishing a forward channel, and a primitive Walsh code having a shortest length is used at the highest data rate. At a data rate 1 / N lower than the maximum data rate, a Walsh code obtained by repeating the basic Walsh code or the inverted code of the basic Walsh code N times according to a specific pattern is used. Therefore, the base station may pre-assign the basic Walsh code to the mobile station at the start of service, and transmit repeating pattern information of the basic Walsh code according to the data rate in the frame rate indication in each frame. In this case, the mobile station combines the basic symbol values obtained by multiplying the basic Walsh code by the received signal according to the repetition pattern to obtain symbol values suitable for the transmission rate. For example, a mobile station assigned a basic Walsh code (+1 +1 -1 -1) sequentially multiplies and integrates (+1 +1 -1 -1) the received signal of 4 chips to integrate the basic symbol S1. Repeat the process of multiplying and integrating (+1 +1 -1 -1) the received signal of the next four chips sequentially to obtain the basic symbol S2. At the same time, the mobile station detects and confirms the rate information. If the rate is 1/2 of the highest rate and the repetition pattern is (+1 +1), the mobile station obtains the symbol value of the rate as S1 + S2. In addition, when the repetition pattern is (+1 -1), the symbol value of the corresponding data rate is obtained as S1-S2. In another Walsh code allocation method, a base station assigns each mobile station the longest Walsh code corresponding to a low data rate at the start of a service, and an upper Walsh code that becomes a component of the longest Walsh code at a data rate higher than the lowest data rate. May be designated by the base station for use by one of the mobile stations using the lower Walsh code, which is a combination of the upper Walsh codes. Here, the mobile station can uniquely find out the corresponding Walsh code from the rate information.

When various frame lengths are used, the base station can inform the mobile station of the desired frame length through a dedicated control channel message. When the frame length is uniquely determined according to the data rate, the frame length can be distinguished only by displaying the data rate without displaying a separate frame length.

In addition, the MUX may be implemented as a means for inserting the rate indicator into the frame data through the additional channel.

20 is a diagram showing the structure of a base station and a mobile station for performing efficient forward packet data transmission according to the present invention.

Reference numeral 200 is a base station, and 300 is a mobile station. The base station 200 includes an additional channel transmission controller 205, a common pilot transmitter 201, a channel state information receiver 203, a rate indicating transmitter 207, and an additional channel transmitter 209. The common pilot transmitter 201 continuously transmits a common pilot signal which is a base station signal through a forward pilot channel. The channel state information receiver 203 receives a channel state report from any mobile station in response to the common pilot signal and transmits channel state information to the additional channel transmission controller 205. The additional channel transmission controller 205 receives the channel state information input from the channel state information receiver 203 and determines the power, frame length, and data rate of data to be transmitted to the mobile station which has reported the channel state. The additional channel transmission controller 205 controls the additional channel transmitter 209 to transmit data at the determined power, frame length, and data rate. The additional channel transmitter 209 transmits data under the control of the additional channel transmission controller 205. At this time, the base station may insert a rate indicator into the data and transmit the data as shown in FIG. 19A. The base station may also have a rate indicator transmitter 207 to transmit the rate indicator on a separate channel. The rate indicator transmitter 207 generates a rate indicator under the control of the additional channel transmission controller 205 and transmits the rate indicator to the mobile station through a channel spread with a separate Walsh code. The rate indicator may include data rate and Walsh code and length information of Walsh code to be used.

The mobile station 300 includes a channel state meter 301, a channel state report transmitter 303, a rate indication receiver 305, and an additional channel receiver 307. [0098] The channel state meter 301 receives a pilot signal through a forward common pilot channel. The strength of the pilot signal is measured to output channel state information to the channel state report transmitter 303. The channel state report transmitter 303 receives the channel state information and transmits a channel state report to the base station. The additional channel receiver 307 detects a data rate indicator from the received signal and receives data at the frame length and data rate detected by the rate indicator.

21 is a flowchart illustrating an operation of a base station for transmitting a data rate indicator by inserting a data rate indicator in accordance with the present invention.

Referring to FIG. 21, the base station first generates a common pilot signal from the common pilot transmitter 201 in step 400 and continuously transmits the data through the forward pilot channel. The base station receives a channel state report from the mobile station in response to the common pilot signal through the channel state information receiver 203 in step 402. In this case, when the channel status report is received from the mobile station, the base station proceeds to step 404 and searches the channel card buffer 113 of FIG. 3 to determine whether there is data to be transmitted to the mobile station. If there is data to be transmitted to the mobile station, the base station determines power, frame length, and transmission rate according to the channel state report in step 406. When the power, frame length, and transmission rate are determined, the base station proceeds to step 408 to transmit data through the additional channel transmitter 209. At this time, the base station may insert a rate indicator into the data and transmit.

22 is a diagram showing the operation of a mobile station according to the present invention. A description with reference to FIG. 22 is as follows.

First, the mobile station measures the strength of the common pilot signal received through the common pilot channel through the channel state meter 301 in step 502. If the strength of the common pilot signal is measured in step 502, the mobile station controls the channel state meter 301 to generate channel state information in step 504. The generated channel state information is input to the channel state report transmitter 303 and transmitted to the base station in step 506. When the channel state information is transmitted to the base station, the base station monitors the additional channel in step 508 to check whether data is received from the base station. At this time, when data is received through the additional channel, the mobile station detects a data rate indicator from the data to demodulate and decode the data.

Alternatively, the base station may send a rate indication through a separate channel as shown in Figure 19b. In this case, the base station should include a rate indication transmitter 207 for transmitting the data rate indicator through a separate channel under the control of the additional channel transmission controller 205 to the base station 300 of FIG. 20 to transmit the rate indicator through a separate channel. . The separate channel may be a data rate indicating channel using a separate code.

The mobile station should also have a rate indication receiver 305 corresponding to the rate indication transmitter 207. The rate indication receiver 305 receives a rate indicator from a base station through a separate channel, and analyzes the rate indicator to detect power, frame length, and data rate of data to be received. The rate indication receiver 305 outputs information on the detected power, frame length, and data rate to the additional channel receiver 307. The additional channel receiver 307 then receives data according to the frame length and data rate and performs demodulation and decoding.

23 is a diagram illustrating a channel state reporting process of a mobile station. Here, a case where the channel state information is represented in the above-described channel state information bit form will be described as an example. The mobile station receives and measures the common pilot channel in step 520a. In step 520b, the mobile station calculates the previous N channel state information bit accumulated values T as shown in Equation (1). In operation 520c, the difference value obtained by subtracting a specific reference value from the common pilot measurement value is compared with the T value obtained in operation 520b. If the difference is greater than T, the controller proceeds to step 520d and sets the channel status information bit to +1. On the contrary, if the difference is not greater than T, the process proceeds to step 520e and sets the channel status information bit to -1. Thereafter, in step 520f, the mobile station transmits channel state information in the form of channel state information bits to the base station.

24 is a diagram illustrating a transmission rate determination process of a base station. In FIG. 24, for convenience of description, it is assumed that three transmission rates (RATE 3> RATE 2> RATE 1) exist, but it should be noted that a higher number of transmission rates may exist than this. In this case, the channel state information is described in the form of the above-described channel state information bit as an example. The base station may accumulate the previous N channel state information bits received as the channel state report in step 410a to obtain common pilot strength information. In step 410b, the base station that has obtained the channel state information determines the transmission rate using the channel state information. The base station first calculates the face rate as proportional to the transmit power and proportional to the common pilot strength representing the channel condition. That is, it is determined by the face rate = K, the power, and the common pilot strength (K is a constant). In step 410c, it is checked whether the calculated face rate is greater than or equal to the largest allowable rate RATE 3. In step 410c, if the face rate is not greater than or equal to the largest allowable rate RATE 3, that is, in step 410g, it is checked whether the face rate is greater than or equal to the second allowable rate RATE 2. In step 410g, if the face rate is not greater than or equal to the second largest allowable rate RATE 2, that is, in step 410j, it is checked whether the face rate is greater than or equal to the third largest allowable rate RATE 1. In step 410j, if the face rate is not greater than or equal to the third largest allowable rate RATE 1, that is, if it is small, the process proceeds to step 410m to determine that the data rate is 0, that is, no data is transmitted.

On the other hand, when the face rate is compared with the allowable rates RATE 3, RATE 2, and RATE 1 in steps 410c, 410g, and 410j, respectively, the face rate is greater than or equal to the allowable rate R of one of RATE 3, RATE 2, and RATE 1, respectively. If it is determined that the step 410c or step 410g or step 410j to step 410d, step 410h, step 410k, respectively. In addition, if the process proceeds to step 410d, 410h, or 410k, it is determined whether Walsh code allocation is possible at the allowable transmission rate R. If it is determined that R is not possible, and Walsh code assignment is not possible, the Walsh code assignment check is repeated at the next allowable transmission rate lower than the allowable transmission rate R. Assign.

The channel card structure of the base station for allocating the data rate and the transmission power will be described with reference to FIG.

The base station channel card buffer 113 stores data to be sent to each mobile station in service. In FIG. 3, the number of mobile stations served by the base station channel card is represented by N. In FIG. The buffer controller 115 controls read / write of buffer data according to a command of a higher layer. Buffer control is described in more detail later. The switch array unit 117 has one switch corresponding to the buffer data for each mobile station to form a switch array having N elements. The switch controller 119 controls the connection / opening operation of the switches constituting the switch array unit 117 so that only data to a specific mobile station can be output during a specific time interval. The switch array unit 117 blocks an output when data transmission is impossible due to a poor channel environment. The gain multiplier 121 multiplies the data corresponding to each mobile station switched by the switch array unit 117 with a gain Pi1 / 2 + Gi (i = 1, 2, ..., N). Pi1 / 2 multiplied by the unit power signal is the ⑨ gain value for Pi to output power corresponding to each mobile station. The mobile station specific power Pi may be a variable value or a fixed value. Incidentally, the base station may perform power control to more adapt the transmission power allocated to the mobile station to the channel. Gi is a gain value obtained by the power control to be zero or smaller than zero. Since the allocated power has a maximum value, Gi must have a value less than 0 to reduce the value of the power having the maximum value. Thus the i th gain is between 0 and Pi1 / 2. In particular, when the frame length is short and Pi is updated every frame, power control is not performed. That is, it is preferable to set Gi to zero and to set the gain to Pi 1/2. The signal multiplied by the gain is input to the spreader 123. The spreader 123 multiplies the signal multiplied by different spreading codes for CDMA transmission and outputs the multiplier to the summer 125. The summer 125 adds the signals output from the respective spreaders 123 and outputs a signal to be transmitted.

Up to now, the process of receiving a channel state report from a mobile station and determining and transmitting power and data rate of packet data to be transmitted to the mobile station according to the channel state report has been described. Hereinafter, a description will be given of a packet data processing process at the time of handoff at a base station and a mobile station using the above method.

1 is a diagram showing the configuration of a mobile communication system to which the present invention is applied. FIG. 1 shows that when the mobile station 109 is located in two base stations 105 and 107, the mobile station 109 communicates with the two base stations 105 and 107 to perform a handoff. The mobile communication system for handoff includes a network 101, a base station controller 103, base stations 105 and 107 connected to the base station controller 103, and a mobile station 109. When trying to send data from network 101 to mobile station 109, network 101 sends this data to base station controller 103. The base station controller 103 transmits the data received from the network 101 to a base station capable of serving the mobile station 109. In this case, the number of base stations may be one or more. FIG. 1 illustrates a case where there are two base stations 105 and 107 capable of servicing a mobile station 109, i.e., at least a certain level of radio waves can reach the mobile station 109. The mobile stations 105 and 107 transmit data received from the base station controller 103 to the mobile station 109 via a radio channel.

Hereinafter, a method of performing a handoff when two or more base stations operate as described above and the mobile station receives service from the two or more base stations will be described.

In the method for performing handoff according to the present invention, a method of dividing and transmitting different data to two base stations may be used first, and second, a method of transmitting same data to two base stations.

The first method for performing the handoff is that the base station controller 103, which has received data to be sent to the mobile station from the network 101, divides the original data into different data 1 and data 2, and divides the data 1 to the base station 105 as shown in FIG. The data 2 is then transmitted to the base station 107. Base stations 105 and 107 receive data 1 and data 2 and transmit them to the target mobile station. The mobile station adds the data received from each base station to obtain the data sent by network 101.

5 is a diagram illustrating a receiving end structure of a mobile station for receiving the data. Hereinafter, a receiving end structure of a mobile station for performing handoff will be described with reference to FIG.

The mobile station includes a plurality of receiving fingers to simultaneously receive signals from two or more base stations. Since the finger structure is a known technique, detailed description thereof will be omitted.

In FIG. 5, the data 1 transmitted from the base station 105 is received by the finger 1 135 and the finger 2 136 through the delay 1 131 and the delay 2 132 set by the searcher (not shown), and the finger 1 135 and the finger. 2 136 receives the corresponding despread code and despreads the data 1 and outputs the despread code. The data 2 transmitted from the base station 107 is received by the finger 3 137 and the finger 138 through the delay 3 133 and the delay 4 134 set by the corresponding searcher, and the fingers 3 137 and the finger 4 138 receive the corresponding despreading code. Despread the data 2 and output it. The data 1 despread and output from the fingers 1 135 and 2 136 is summed and output by the adder 139 and outputs data 1 which is original data through the symbol determiner 141 and the decoder 1 143. Data 2 which is despread and output from the fingers 3 137 and 4 138 is summed and output by the summer 140 and outputs data 2 which is original data through the symbol determiner 1142 and the decoder 144.

In a handoff situation, the mobile station carries the channel state information on the reverse channel to report the channel state to the base station. In this case, an asymmetric power control scheme in which the mobile station transmits different channel state information for a plurality of base stations using a plurality of power control bits may be used for channel state reporting. Within the power control group of the reverse channel, separate power control bits are included for each base station. Asymmetric power control is described in detail in the previously filed application No. PCT KR 98-00186, and the description thereof is omitted. 6 is a diagram illustrating a channel state report in a handoff state, in which a mobile station 109 receives a signal through forward channel 1 from base station 105, reports a state of forward channel 1, receives a signal through forward channel 2 from base station 107, and It shows how to report the status of channel 2. The mobile station 109 carries both channel state information 1 indicating the state of the forward channel 1 and channel state information 2 indicating the state of the forward channel 2 on the reverse channel.

FIG. 7 is a flowchart illustrating a handoff method according to the first method according to an embodiment of the present invention. Referring to this, the first method will be described in detail with reference to the configuration of FIG. 4.

FIG. 7A is a flowchart illustrating an operation of the base station controller 103 for executing the first method. The base station controller 103 receives data from the network 101 in step 501. When the data is received, the base station controller 103 receives channel state information from base stations belonging to the base station set in which the mobile station 109 to which the data is to be transmitted is currently located. Then, the base station controller 103 identifies the base stations capable of servicing the mobile station 109 to receive data from the channel state information received in step 505. When the base station capable of serving the mobile station 109 is identified, the base station controller 103 divides the data into the base stations and transmits the data to each base station in step 507. In the following description, it is assumed that a handoff base station capable of serving a mobile station 109 is identified as a base station 105 and a base station 107. In this case, different data 1 and data 2 are stored in the buffers of the base station 105 and the base station 107 as shown in FIG. 8. Also, the base station controller 103 may transmit other data sequentially divided after the divided data as shown in FIG. 10 in case the base station 105 or 107 cannot transmit the divided data to the mobile station 109.

In FIG. 4, data 1 and data 2 transmitted to the base stations 105 and 107 are transmitted to the mobile station 109 by performing the operation of FIG. 7B. Base station 105 always transmits a base station signal over a forward channel to mobile station 109. The base station signal may be a pilot signal. Referring to FIG. 7B, in operation 511, the base station 105 receives channel state information for channel state reporting from the mobile station 109 in response to the base station signal. When the channel state information for the channel state report is received, the base station 105 may transmit the channel state information to the base station controller 103 in step 513. The channel state information sent by the base station to the base station controller may be different from the channel state information sent by the mobile station to the base station. For example, the message may be generated according to a channel state.

Here, the process of the base station is divided into two embodiments.

In the case of the first embodiment, the base station 105 may additionally adjust the traffic channel power gain according to the channel state information (which may also be a power control bit) in step 515. The base station 105 then checks in step 517 whether the target mobile station 109 has the best channel state (with QoS weights). As a result of the check, if the mobile station 109 has the best channel state, the base station 105 proceeds to step 519 to allocate transmission power according to the channel state. When the transmission power is allocated, the base station 105 proceeds to step 520 to determine the data rate and transmits data to the mobile station 109 in step 521. On the other hand, the mobile station 109 does not transmit data unless the channel state is the best state. The base station 107 performs the same operation as above to determine whether data is transmitted to the mobile station 109.

In the case of the second embodiment, the base station 105 performs steps 551 and 553 performing the same operations as steps 511 and 513 as shown in FIG. 7D, and then checks the channel state of the target mobile station 109 and then moves the channel to the mobile station 109 in step 555. The transmission data rate is determined according to the state, and the data is transmitted to the mobile station 109 in step 557.

7C is a flowchart illustrating a data processing method in handoff of a mobile station according to the present invention. Referring to FIG. 7C, the mobile station 109 first identifies handoff base stations capable of serving itself in step 531. Then, in step 533, the mobile station 109 receives the respective signals from the base stations 105 and 107 through the corresponding forward channel, and measures the received power (Ec / Io) for the base stations 105 and 107 in step 535. When the received power is measured, the mobile station 109 reports the information on the state of the forward channel from the base stations 105 and 107 to the base stations 105 and 107 in step 537. Here, the channel state report may include individual channel state information for each base station. The mobile station 109 then checks whether different data are received for each base station from the identified handoff base stations 105 and 107. As a result of the check, when different data transmitted from the base stations 105 and 107 as shown in FIG. 8 are received, the process proceeds to step 541 and the data 1 received from the base station 105 and the data 2 received from the base station 107 are respectively as shown in FIG. 5. Demodulating the data, and in step 543, combines the demodulated data 1 and data 2 to restore the original data transmitted from the base station controller 103. In this case, the mobile station may receive data rate information from the base station or detect itself in order to perform demodulation. On the other hand, if different data is not received for each base station, it is checked whether data from one base station is received in step 545. If data is received even from one base station, the data is demodulated and the demodulated data is combined with previously received data. On the other hand, if no data is received from any base station, the process ends without data demodulation.

8 is a diagram illustrating a data buffer state of the base station 105 and the base station 107 in the handoff state in the handoff method of sending different data to the two base stations. In FIG. 8, when the channel conditions of the mobile station and each of the two base stations are all good, the two base stations 105 and 107 transmit respective data stored in the data buffer of the mobile station.

When data transmission is delayed due to poor channel condition between one of the two base stations and the mobile station, the base station controller 103 relays the entire data from the base station having the data transmission delay to the base station where the data transmission is performed first. Can give

9 is a diagram illustrating a data transmission method for improving data throughput during handoff according to an embodiment of the present invention. 9, the base station 105 or 107 allocates power according to the channel state every frame and determines the data rate (first embodiment), or fixedly allocates power every channel The data rate is determined according to the state (second embodiment) to transmit data to the mobile station. Therefore, the data to be transmitted to the specific mobile station 109 is outputted from the buffer only when the channel state between the base station 105 or 107 and the mobile station 109 is good, that is, when zero or more power is allocated and the data rate is determined to be zero or more. If the channel conditions are good at both base stations, different data of the two base stations may be simultaneously transmitted to the mobile station. When data to be transmitted to the mobile station is transmitted to the base station 105 and the base station 107 as data 1 and data 2, respectively, data 1 may be smoothly transmitted, whereas data 2 may have a poor channel state, resulting in a delay in data transmission. . In this case, as illustrated in FIG. 9, the base station controller 103 may use a method of relaying data 2 to the base station 105 having a good channel state through a wired transmission path.

A method of relaying data to be transmitted from a base station having a poor channel state to a base station having a good channel state will be described with reference to the procedure diagram of FIG. 16, and operations of the base station controller 103, base station 105, 107, and mobile station 109 according to the procedure diagram. This will be described with reference to FIG. 18. 16 and 18, the channel states of the mobile station 109 and the base station 105 are good, and the channel states of the mobile station 109 and the base station 107 are not good. An example is demonstrated.

First, referring to FIG. 16, when data transmitted to the mobile station 109 is generated from the outside, the base station controller 103 divides the data into data 1 and data 2 in step 201, divides the data 1 into the base station 105, and the base station 107. Send data 2. The base station 105 receives data 1 from the base station controller 103. When the data 1 is received, the base station 105 transmits the data 1 to the mobile station 109 in step 202 because the channel state of the base station 105 is good. The mobile station 109 receives the data 1 transmitted by the base station 105 and transmits a data 1 reception response signal to the base station 105 to inform the base station 105 that the data 1 has been received in step 203. The base station 105, which has received the data 1 reception response signal from the mobile station 109, transmits the data 1 reception response signal to the base station controller 103 in step 204.

However, the data 2 transmitted to the base station 107 has a poor channel state between the base station 107 and the mobile station 109, resulting in a data transmission delay as shown in FIG. The base station 107 counts the data transmission delay time in step 205, and if the data transmission delay time exceeds a predetermined time, transmits a data 2 transmission failure signal to the base station controller 103 in step 206.

Upon receiving the data 2 transmission failure signal from the base station 107, the base station controller 103 transmits the data 2 to the base station 105 having a good channel state in step 207. The base station 105 which has received the data 2 transmits the data 2 to the mobile station 109 in step 209. The mobile station 109 having received the data 2 from the base station 105 transmits a data 2 reception response signal to the base station 105 in step 211, and the base station 105 receives the data 2 reception response signal, and in step 213 the data 2 reception response signal. Is transmitted to the base station controller 103.

The operation of the base station controller 103 according to the procedure of FIG. 16 will be described with reference to FIG. 18A. First, when the data transmitted from the outside to the mobile station 109 is generated, the base station controller 103 divides the data. The base station controller 103 transmits the divided data to the corresponding base station in step 301. After the data transmission, the base station controller 103 checks whether a response signal is received from the base station which has transmitted the data. In this case, when the response signal is received, the base station controller 103 proceeds to step 305 and determines whether the response signal is a data reception response signal. If the response signal is a data reception response signal, the base station controller 103 ends the data transmission process. If the response signal is not the data reception response signal, the base station controller 103 proceeds to step 307 to retransmit the failed transmission data to another base station having a good channel condition.

Referring to FIG. 18B, the operation of the base station receiving the data transmitted from the base station controller 103 is described. In step 301, the base station determines whether data is received from the base station controller 103. When data is received from the base station controller 103 in step 301, the base station determines whether data transmission is possible to the mobile station 109. This is determined according to the channel state and the QoS as described with reference to FIGS. 1 and 2. As a result of the determination, if data can be transmitted to the mobile station 109, the base station proceeds to step 315 to transmit data to the mobile station 109. However, if data transmission is not possible to the mobile station 109, the base station checks in step 317 whether the transmission delay time of the data exceeds the data transmission time (Data Timeout-data is transmitted to the corresponding mobile station). If the data transmission delay time exceeds the data transmission time, the base station transmits a data transmission failure signal to the base station controller 103 in step 319.

After transmitting data to the mobile station 109 in step 315, the base station proceeds to step 321 to check whether a data reception response signal is received from the mobile station 109. In this case, when the data reception response signal is received from the mobile station 109, the base station proceeds to step 323 and transmits a data reception response signal to the base station controller 103. If the data reception response signal is not received, the base station proceeds to step 325 and the data reception response. Check for signal timeouts. If the data reception response signal timeout occurs, the base station proceeds to step 327 and transmits a data transmission failure signal to the base station controller 103.

The mobile station 109 receiving the divided data from the base station performs the process of Fig. 18C. The mobile station 109 checks in step 331 whether data is received from the base station. In this case, when data is received from the base station, a data reception response signal is transmitted to the base station in step 333.

As another method, the base station controller 103 may transmit the duplicated data to two or more base stations and transmit the data transmission order of each base station with the base station having a good channel status as the priority. That is, in the case of the above example, as shown in FIG. 10, the base station 105 sends data 2 after data 1 as a spare and the other base station 107 sends data 1 after data 2 as a spare and the channel state of the base station 1 is higher than that of the base station 2. If good, the transmission of data 1 is completed first, base station 105 continues to send out data 2. If the channel state of base station 2 is better than the channel state of base station 2, if transmission of data 2 is completed first, base station 107 continues to send data 1. You can export it. Therefore, the buffers of the base stations 105 and 107 store both data 1 and data 2 as shown in FIG. 10 in case the base station transmitting data to the mobile station 109 fails to transmit data. If the base station 107 fails to transmit the data 2 to the mobile station 109, the base station 105 continues to transmit the data 2 after the transmission of the data 1 is completed as described above, and the base station 107 discards the data 2 remaining in the buffer.

This will be described in detail with reference to the procedure diagram of FIG. 17 will be described under the same assumption as FIG. 16.

The base station controller 103 divides the data into data 1 and data 2 when data transmitted from the outside to the mobile station 109 is received. When the data received from the outside is divided, the base station controller transmits data 1 to the base station 105 in step 221, and then transmits data 2 subsequent to the data 1. The base station controller 103 transmits data 2 to the base station 107 in step 223, and then transmits data 1 subsequent to the data 2. This is for the case in which either of the base stations 105 and 107 cannot transmit data to the mobile station 109. The base station 105 sequentially stores the data 1 and data 2 buffers transmitted in step 221. Since the base station 105 has a good channel state formed with the mobile station 109, the first base station 105 transmits the first received data 1 of the data 1 and the data 2 to the mobile station 109. The mobile station 109 receives the data 1 from the base station 105 and then transmits a data 1 reception response signal to the base station 105 in step 227. The base station 105 receives the data 1 reception response signal from the mobile station 109, and transmits the data 1 reception response signal to the base station controller 103 in step 229. The base station controller 103 which has received the data 1 reception response signal transmits a command to discard the data 1 to the base station 107 since the data 1 has been transmitted to the mobile station 109. Base station 107 then deletes data 1 from the buffers storing data 2 and data 1. However, the base station 107, which is in a bad channel state, cannot transmit data 2 and will be delayed in the buffer. If the data transmission delay time in the buffer exceeds the timeout time in step 233, the base station 107 transmits the data 2 transmission failure signal to the base station controller 103 in step 235.

Even if the data 2 fails to be transmitted from the base station 107, since the data 2 is stored in the buffer of the base station 105, the data 1 is transmitted in step 225, and then the data 2 is transmitted to the mobile station 109 in step 237. The mobile station 109 having received the data 2 transmits a data 2 reception response signal to the base station 105 in step 239. The base station 105 which has received the data 2 reception response signal transmits the data 2 reception response signal to the base station controller 103 in step 241. When the data 2 reception response signal is received from the base station 105, the base station controller 103 transmits a command to discard the data 2 to the base station 107 in step 243. The received base station 107 deletes the data 2 from the buffer and terminates the data transmission.

In the second method of performing the handoff, as shown in FIG. 11, the base station controller 103, which has received data to be transmitted from the network 101 to the mobile station 109, duplicates and transmits the same data to two or more base stations. The mobile station 109 may transmit and transmit a best link indicator to the base station for selecting a base station with a channel status report every frame. 12 illustrates a structure of a frame that a mobile station sends to a base station through a reverse channel for channel state reporting. Each frame includes channel state information and may include a best link indicator. The best link indicator indicates information for indicating a base station having the highest reception level in the mobile station of the forward channel signal. The base station selected by the best link indicator may transmit data to the corresponding mobile station for one frame. Any other unselected base station does not transmit data during that frame.

FIG. 13 is a diagram illustrating a data buffer state of the base station 105 and the base station 107 in the handoff state in the handoff method of sending the same data to the two base stations. Here, the base station 105 is selected by the best link indicator from the mobile station 109 to send out data, and the unselected base station 109 does not transmit data. At this time, the base station 109 which does not transmit data updates information on the current data progress status (see FIG. 14), that is, where the transmitted data is and where the next data is to be transmitted in preparation for sending data selected in the next frame. do. This information may be provided to each base station by the mobile station 109 or exchanged between base stations via a wired path (e.g., base station 105 ↔ base station controller 103 ↔ base station 107).

When the mobile station 109 reports the channel status to two or more base stations, the mobile station 109 may report the channel status for each base station ⑩ ⑦, or may combine channel state information for the two or more base stations and transmit them on the same channel. The channel status report according to the latter method is to transmit channel state information of different base stations on one channel, and spread the respective channel state information into codes for distinguishing the corresponding base stations and then to the same channel discrimination code. Can be produced by diffusion.

15 is a flowchart of a handoff method for sending the same data to two or more base stations according to system components. In the above-described FIG. 15, the structure of FIG. 11 will be described.

15A is a flowchart illustrating a second handoff method in the base station controller 103. FIG. Referring to FIG. 15A, the base station controller 103 receives data from the network 101 in step 601. When data is received from the network in step 601, the base station controller 103 receives channel information from the base stations (eg, base stations 105 and 107) managing in step 603. The base station controller 103 then proceeds to step 605 to identify the base stations 105 and 107 capable of servicing the mobile station 109 to receive data from the channel state information received from the base stations. When the base stations 105 and 107 to be serviced to the mobile station 109 are identified, the base station controller 103 transmits data to the base stations 105 and 107 which can be serviced in step 607. At this time, the data transmitted to the base station 105 and 107 is the same data copied.

Data transmitted to the base stations 105 and 107 is transmitted to the mobile station 109 by performing the operation of Fig. 15B. Hereinafter, a method in which the base station 105 or 107 processes data transmitted from the base station controller 103 will be described with reference to FIG. 15B. Since the base stations 105 and 107 perform the same operation, the base stations 105 and 107 are described in the same manner.

The base station reports the channel status from the mobile station 109 in step 611. The base station may transmit channel state information to the base station controller 103 in step 613 if necessary. In addition, the base station may additionally adjust the power gain of the traffic channel according to the channel state information (which may also be a power control bit) received in step 615. The base station then proceeds to step 617 to determine whether the target mobile station 109 has the best mobile station with the base station. If the mobile station 109 is the mobile station having the best channel state, the base station checks whether it is the base station selected by the best link indicator in step 619. As a result of the check, if the base station is selected, the base station allocates transmission power to data transmission to the mobile station 109 in step 621 and transmits data to the mobile station 109 in step 623. On the other hand, if the mobile station 109 is not the best mobile station in the channel state or if it is not the base station selected by the best link indicator, the base station does not transmit data to the mobile station 109.

Fig. 15C is a flowchart showing a handoff method in a mobile station according to the present invention, with reference to this illustrating the operation of the mobile station.

First, the mobile station 109 identifies handoff base stations that can serve it in step 631. When the handoff base station is identified, the mobile station 109 receives a signal from the identified base stations in step 633 and measures the received power for each base station in step 635. The mobile station 109 then transmits a channel status report to each base station based on the measurement result in step 637. The mobile station then transmits, with the channel status report, the best link indicator to the base stations for selecting the base station having the best channel status. The mobile station 109 receives and demodulates data from the base station in step 639.

For example, in FIG. 11, the mobile station 109 identifies base stations 105 and 107 capable of providing a packet service to itself in step 631, and through the forward channel from both or both of base stations 105 and 107 in step 633. Receive base station signals. When the signal is received, the mobile station measures the received power of the signals transmitted from the base stations 105 and 107 in step 635 and reports the channel status to the base station in step 637 based on the measured results. At this time, the mobile station 109 sets the best link indicator to the base station 105 having the best channel state and transmits the same to the channel state report. When the channel state report ends, the mobile station 109 demodulates data received from the base station previously selected in step 639.

As described above, the present invention has an advantage of providing efficient packet service by maximizing data throughput in packet service by transmitting data with priority according to channel state and quality of service during handoff.

Another advantage of the present invention is that the base station inserts and transmits a data rate indicator indicating the data rate to the data currently being serviced, so that the mobile station can cope with the variable data rate to demodulate the received data. .

Claims (47)

A base station for maximizing throughput of packet data in a code division multiple access mobile communication system, A channel state information receiver for receiving channel state information for a forward channel from a plurality of mobile stations; An additional channel transmission controller for determining a data rate of each mobile station based on the channel state information; And an additional channel transmitter for transmitting data to be transmitted to the mobile station at the determined data rate. The apparatus of claim 1, further comprising: a rate indicator transmitter for generating a rate indicator having information on the determined data rate and transmitting the rate indicator to the mobile station. The base station of claim 1, wherein the additional channel transmitter generates a rate indicator having information on the determined data rate, inserts the rate indicator into frame to be transmitted and transmits the data in frame unit. Packet data processing device. The method of claim 1, wherein the transmission rate determination, And analyzing the plurality of channel state information to determine transmission rate by concentrating transmission power to the mobile station having the best channel state. The method of claim 1, wherein the rate determination is And analyzing the plurality of channel state information to obtain a transmission rate and multiplying the transmission rate by a weight to determine a final transmission rate. The method of claim 1, wherein the rate determination is Packet data processing apparatus in a base station of a mobile communication system, characterized in that it is determined in proportion to the fixed power in inverse proportion to the channel state information indicating the common pilot strength received from a plurality of mobile stations. The apparatus of claim 1, further comprising: a rate indicator transmitter for transmitting the determined data rate to a mobile station through a separate channel. A mobile station of a code division multiple access mobile communication system, A channel state meter for detecting channel power by detecting power of a signal received through a pilot channel; A channel state report transmitter for generating and reporting channel state information according to the channel state measurement; And an additional channel receiver which detects a data rate transmitted from the base station at a variable data rate and receives data at the data rate. 10. The method of claim 8, wherein the additional channel receiver detects a transmission rate of the received data by detecting a transmission rate indicator inserted in units of frames in the data transmitted from the base station. Device. The apparatus of claim 8, wherein the additional channel receiver detects a data rate of the received data by performing a blind detection on the data transmitted from the base station. A mobile station of a code division multiple access mobile communication system for transmitting data at a variable data rate when transmitting data through an additional channel, A channel state meter for detecting channel power by detecting power of a signal received through a pilot channel; A channel state report transmitter for generating and reporting channel state information according to the channel state measurement; A rate indicating receiver for detecting a rate of data transmitted from the base station; Packet data processing apparatus of a mobile station in a mobile communication system, characterized in that the additional channel receiver for receiving data in accordance with the transmission rate of the detected data. 12. The apparatus of claim 11, wherein the rate indicator receiver detects rate information of the data transmitted through a separate channel at a base station. A data processing method for packet service of a base station in a code division multiple access mobile communication system, Transmitting a signal having a predetermined power through a predetermined forward channel; Receiving predetermined channel state information on the forward channel from a plurality of mobile stations through a predetermined reverse channel, and determining a transmission rate of data to be transmitted to the mobile station according to the channel state information; And transmitting data to the mobile station at the determined data rate. 14. The method of claim 13, wherein the forward channel is a common pilot channel. 14. The method of claim 13, wherein the forward channel is a traffic channel. 14. The method of claim 13, wherein the reverse channel is a reverse pilot channel. The method of claim 13, wherein the reverse channel is a channel state reporting channel. 18. The method of claim 17, wherein the channel status reporting channel is a Walsh code channel. The method of claim 14, wherein the rate determination process, And analyzing the channel state information received from the plurality of mobile stations to determine a transmission rate by concentrating transmit power to the mobile station having the best channel state. 20. The method of claim 19, wherein the transmission rate is determined by Equation 5 below. Given The method of claim 14, wherein the rate determination process, And analyzing the channel state information received from the plurality of mobile stations to obtain a transmission rate, and multiplying the transmission rate by a weight to determine a final transmission rate. The method of claim 21, wherein the transmission rate is determined by Equation 6. Given The method of claim 14, wherein the rate determination, And in proportion to a fixed power and inversely proportional to channel state information indicating a common pilot strength received from a plurality of mobile stations. 24. The method of claim 23, wherein the rate determination is determined by Equation 7 below. Face rate = K, fixed power, common pilot strength Where K is a constant The method according to any one of claims 20 or 22 or 24, Generating a rate indicator for the determined data rate and transmitting it to the mobile station over a forward channel. The method of claim 25, wherein the data rate generation process, A basic Walsh code is allocated when the determined data rate is maximum, and 1 / N when the determined data rate is maximum, and the base Walsh code is repeatedly generated N times. A data processing method for packet service of a mobile station in a code division multiple access mobile communication system, Receiving a signal received through a forward channel from a base station and generating channel state information for the forward channel; Reporting the channel state information to the base station through a predetermined reverse channel; And detecting a data rate of data received at a variable data rate in response to the channel state information to process the data. 28. The method of claim 27, wherein the forward channel is a common pilot channel. 29. The method of claim 27 wherein the forward channel is a traffic channel. The method of claim 28, wherein the channel state information generation process, Detecting power and change trends of pilot signals received through the pilot channel; And generating channel state information bits according to power and change trends of the detected pilot signals. The method of claim 30, wherein the channel state information bit generation process, Calculating a cumulative value of a previous channel state information bit; Determining whether a value obtained by subtracting a predetermined reference value from a common pilot measurement value measured through the common pilot channel is greater than an accumulated value of the channel state information bits; And setting the channel state information bit to +1 if the value obtained by subtracting a predetermined reference value from the common pilot measurement value is greater than the accumulated value, and to -1 if the value is smaller than the accumulated value. The method of claim 31, wherein The cumulative value of the channel state information bit is calculated by Equation 8. The method of claim 29, wherein the channel state information generation process, Detecting power of a traffic signal received through the traffic channel; And generating a power control bit according to the power of the detected traffic signal. 28. The method of claim 27, wherein the data rate received at the variable data rate is detected by a blind scheme. 35. The method of claim 34, wherein the blind method performs data detection on a possible data rate and selects a data rate at which a circuit check code (CRC) is matched. A method of maximizing data throughput in a packet service of a mobile communication system comprising a network, a base station controller, a base station, and a mobile station, A first process of receiving, by the base station controller, the data through the network and transmitting the data to at least one base station when data provided to the mobile station is generated; Determining a data rate to the mobile station according to channel state information periodically reported by the mobile station by the base station receiving data from the base station controller, and then transmitting the data to the mobile station at the determined data rate; A third step of the mobile station receiving a base station signal from the base station through a forward channel, periodically reporting a channel state of the forward channel from the signal to the respective base stations as channel state information, and receiving data from the base station; Method characterized in that consisting of. The method of claim 36, wherein the first process, A first step of receiving data through a network when data is generated to the mobile station; A second step of receiving channel state information from base stations belonging to a base station set currently located by the mobile station when the data is received; Determining a base station capable of serving data to the mobile station from the channel state information; And a fourth step of transmitting data to each of the determined base stations when the base station is determined. 38. The method of claim 37, wherein the data transmitted to each base station is identical data. The method of claim 37, wherein the data transmitted to each base station is different data obtained by dividing data received through the network into a predetermined size. The method of claim 36, wherein the second process, A first step of periodically receiving a channel status report from the mobile station; And a second step of allocating transmit power for the mobile station, determining a data rate and transmitting data. 41. The method of claim 40, wherein the transmission power allocation, Wherein the channel states included in the channel state information reported by the plurality of mobile stations are prioritized in good order, and power is allocated in the determined priorities. 41. The method of claim 40, wherein the transmission power allocation, Assigning a fixed power to a plurality of mobile stations. The method of claim 40, wherein the data rate determination, And determining a new data rate for each frame based on channel status reports received from a plurality of mobile stations. 44. The method of claim 43, wherein the data rate is determined to be higher as the channel state is better. 37. The method of claim 36, wherein the base station informs the mobile station of the determined data rate through a separate data rate indication channel having a fixed rate. 37. The method of claim 36, wherein the base station inserts a rate indication indicating the determined data rate into an additional channel for data transmission and transmits it to the mobile station. The method of claim 36, wherein the additional channel frame length for data transmission in the second process of transmitting the data to the mobile station by the base station is 1.25 ms or 2.5 ms.