WO2006095387A1

WO2006095387A1 - Scheduling method, and base station device

Info

Publication number: WO2006095387A1
Application number: PCT/JP2005/003732
Authority: WO
Inventors: Satoshi Yamagiwa; Seiji Hamada
Original assignee: Fujitsu Limited
Priority date: 2005-03-04
Filing date: 2005-03-04
Publication date: 2006-09-14
Also published as: JPWO2006095387A1

Abstract

Provided is a wireless data transmission system for transmitting data from a net side to a predetermined mobile terminal through a wireless line shared by a plurality of mobile terminals. A scheduler calculates such an index value on the basis of the quality of the received signal at each mobile terminal as to select what mobile terminal is to be selected, corrects that index value with the quality fluctuation factor of the received signal, a fading frequency or an error factor for each CQI, and selects the mobile terminal, to which the data is to be sent out, on the basis of the corrected index value.

Description

Specification

Scheduling method and base station apparatus

Technical field

TECHNICAL FIELD [0001] The present invention relates to a scheduling method and a base station apparatus, and more particularly, to a scheduling method and a base in a wireless data transmission system for transmitting data from a network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals. It relates to station equipment.

Background art

[0002] There are several wireless communication systems in which a line is shared by multiple users. Here, a W-CDMA (UMTS) mobile communication system will be described as an example. Figure 17 shows a configuration example of a W-CDMA mobile communication system. In the figure, 1 is a core network, 2 and 3 are radio base station controllers (RNCs), 4 and 5 are demultiplexers, 6-6 are radio base stations (RodeB), 7 are mobile stations (UEs) : User equipment)

1 5

Show.

The core network 1 is a network for performing routing in the mobile communication system. For example, the core network can be configured by an ATM switching network, a packet switching network, a router network, or the like. The core network 1 is also connected to other public networks (PSTN) or the like, and the mobile station 7 can communicate with a fixed telephone or the like.

[0003] The radio base station control devices 2 and 3 are positioned as upper devices of the radio base stations 6-6,

1 5

Functions to control these radio base stations 6-6 (management of radio resources to be used, etc.)

1 5

It is. It also has a handover control function that receives signals from one mobile station 7 from a plurality of subordinate radio base stations, selects data with better quality, and sends it to the core network 1 side at the time of handover. The

The demultiplexers 4 and 5 are provided between the RNC and the radio base station, demultiplex signals received from the RNC 2 and 3 to the radio base stations, output the signals to the radio base stations, and Control is performed by multiplexing the signals from the line base station and passing the bow to each RNC.

Radio base stations 6-6 manage radio resources by RNC2, and radio base stations 6, 6 manage radio resources by RNC3

1 3 4 5

However, wireless communication with the mobile station 7 is performed. The mobile station 7 By being in the network, a wireless line is established with the wireless base station 6 and communication is performed with other communication devices via the core network 1.

The interface between the core network 1 and RNC2, 3 is the Iu interface, the interface between RNC2, 3 is the Iur interface, the interface between RNC2, 3 and each radio base station 6 is the Iub interface, and the radio base station 6 The interface with the mobile station 7 is called the Uu interface, and the network formed by 2-6 devices is called the radio access network (RAN). The line between the core network 1 and RNC2 and 3 is shared for the Iu and Iur interfaces, and the line between the RNC2 and 3 and the demultiplexer 4 and 5 is the Iub for multiple radio base stations. Shared by the interface.

The above is a description of a general mobile communication system. Furthermore, the HSDPA (High Speed Downlink Packet Access) system may be adopted as a technology that enables high-speed downlink data transmission (Non-patent Document 1). , 2). Here, we will briefly explain HSDPA.

• HSDPA

HSDPA employs Adaptive Code Modulation and Coding (AMC). For example, QPSK modulation scheme (QPSK modulation scheme) and 16-value QAM scheme (16 QAM scheme) It is characterized by adaptive switching according to the radio environment between stations.

HSDPA adopts the H-ARQ (Hybrid Automatic Repeat reQuest) method. In H-ARQ, when a mobile station detects an error in the received data of a radio base station, it makes a retransmission request (transmission of a NACK signal) to the radio base station. The radio base station that has received this retransmission request retransmits the data, so that the mobile station performs error correction decoding using both the already received data and the retransmitted received data. In this way, in H-ARQ, even if there is an error, the already received data is used effectively, increasing the gain of error correction decoding and consequently reducing the number of retransmissions. When the ACK signal is received by the mobile station, the data transmission is successful, so no retransmission is necessary, and the next data transmission is performed.

The main radio channels used in HSDPA are (1) HS-SCCH ( High Speed-Shared Control Channel (2), HS—PDSCH (High Speed-Physical Downlink Shared Channel), (3) HS—High Speed-Dedicated Physical Control Channel (DPCCH).

HS-SCCH and HS-PDSCH are both shared channels in the downlink direction (that is, the downlink from the radio base station to the mobile station), and HS-SCCH is defined in HS-PDSCH. This is a control channel that transmits various parameters related to the data to be transmitted. In other words, it is a channel that notifies that data is transmitted via HS-PDSCH. Various parameters include, for example, modulation scheme information indicating which modulation scheme is used to transmit data by HS-PDSCH, the number of assigned spreading codes (number of codes), and the rate for transmission data There is a blueprint for matching patterns.

On the other hand, the HS-DPCCH is a dedicated control channel in the uplink direction (that is, the uplink from the mobile station to the radio base station), and an error occurs in data received via the HS-PDSCH. This is used when the mobile station transmits a reception result (ACK signal, NACK signal) to the radio base station depending on whether or not there is. That is, it is a channel used to transmit the reception result of data received via H S-PDSCH. If the mobile station fails to receive data (such as when the received data is a CRC error), the NACK signal is transmitted from the mobile station, so the radio base station executes retransmission control.

In addition, HS-DPCCH is also used by mobile stations that measure the reception quality (for example, SIR) of received signals from radio base stations to transmit the reception quality to the radio base station as CQI (Channel Quality Indicator). It is done. In other words, CQI is information for the mobile station to report the reception environment to the base station. CQI takes a value of 1-30, and the block error rate BLER does not exceed 0.1 under the reception environment. Report the CQI value to the base station.

Based on the received CQI value, the radio base station determines whether the radio environment in the downlink direction is good or not. If it is good, the radio base station switches to a modulation method capable of transmitting data at a higher speed, and vice versa. Switch to a modulation scheme that transmits data (ie, perform adaptive modulation). Actually, the base station defines a format with different transmission rates according to CQI = 1-30. A table is held, and the parameters (transmission rate, modulation method, number of multiplexed codes, etc.) corresponding to the CQI value are obtained from the table and notified to the mobile station by HS-SCCH.

· Channel structure

FIG. 19 is an explanatory diagram of the channel configuration in HSDPA. In W-CDMA, since the code division multiplexing system is adopted, each channel is separated by a code. CPICH (Common Pilot Channel) and SCH (Synchronization Channel) are common channels in the downlink direction. CPICH is a channel used for channel estimation, cell search, etc. in a mobile station, and is a channel for transmitting a so-called pilot signal. Strictly speaking, there are P-SCH (Primary SCH) and S-SCH (Secondary SCH), and the SCH is a channel transmitted in bursts by the first 256 chips of each slot. This SCH is received by a mobile station that performs a three-stage cell search, and slot synchronization and frame synchronization are established.

Used to identify the base station code (scramble code). SCH is the length of 1Z10 in 1 slot, but is shown wider in the figure. The remaining 9Z10 is P-CCPCH.

Next, channel timing relationships will be described. Each channel is composed of 15 slots to form one frame (10 ms), and each frame has a length equivalent to 2560 chips. As described above, since CPICH is used as a reference for other channels, the frame head of SCH + P-CCPCH and HS-SCCH coincides with the head of the CPICH frame. On the other hand, the head of the HS-PDSCH frame is delayed by 2 slots with respect to the HS-SCCH, etc. This is because the mobile station receives the modulation method information via the HS-SCCH and then receives the modulation received. This is because HS-PDSCH can be demodulated using a demodulation method corresponding to this method. HS-SCCH and HS-PDSCH consist of 3 slots and 1 subframe.

HS—DPCCH is an uplink channel, and the first slot of the HS—DPCCH sends an ACKZNACK signal indicating the HS—PDSCH reception result to the radio base station after about 7.5 slots have elapsed since the HS—PDSCH was received. Used to do. In the second and third slots, CQI information for adaptive modulation control is periodically sent back to the base station. Used for Here, the CQI information to be transmitted is calculated based on the reception environment (for example, SIR measurement result of CPICH) measured during the period from 4 slots before 1 slot before CQI transmission.

'Scheduler

The scheduler determines the transmission target (mobile station) and the transmission speed, modulation method, and the like based on the index value calculated based on the channel quality and the transmission data rate. The scheduler is a power used in various communication systems Here, a scheduler that is applied to a mobile communication system adopting the HSDPA method will be described as an example. In HSDPA, the physical downlink data channel HS-PDSCH described above is shared by multiple mobile stations, so it is necessary to select a mobile station to be transmitted, and the scheduler is involved in mobile station selection control. Fig. 20 shows a configuration example in the HSDPA system. Two radio base station devices 6-6 are connected to one radio base station control device 2, and the radio base station device

1 2

6 is communicating with subordinate mobile stations 7-7, and radio base station device 6 is under control

1 1 m 2

Communicating with stations 7 and 7.

(m + l) n

Based on the CQI and HARQ information (ACKZN ACK information) received from the mobile station, the scheduler SJL of each base station selects the mobile station to transmit data (mobile station selection control) and receives the CQI information from the mobile station. The transmission data volume, modulation method, power, etc. are determined based on the above, and the channel coding unit CCD is instructed. Further, the scheduler SJL requests the data addressed to each mobile station from the radio base station controller 2 based on the scheduling result (flow control). The radio base station controller 2 is addressed to each mobile station 7-7 received via the core network.

1 n Data is held, and the data addressed to the requested mobile station is sent in response to a request from the scheduler SJL. Buffer section BUF of base station 6-6 is sent from radio base station controller 2

1 2

The data addressed to each mobile station is stored, and the data addressed to the mobile station specified by the instruction from the scheduler SJL is input to the channel coding unit CCD in the requested block size. Channel coding unit CCD adds CRC code for each block to the data destined for the mobile station, encodes it for every predetermined number of blocks, and modulates each mobile by modulating with the modulation method specified by the scheduler Send to the station.

As a user selection algorithm in the scheduler, the Maximum CIR method and Proportional fairness methods have been proposed (see Non-Patent Document 3). Maximum CIR method is a method to select users with good line quality. It is not assigned to users with poor line quality and there is no fairness. In contrast, the Proportional Fairness method is

[Number 1]

R _n (do) ZAve R _n (i- (1) is used to calculate the index value C and select the one with a high index value C.

n (PF) n (PF)

This is a method for improving the throughput while maintaining the above. In Eq. (1), R is the instantaneous channel quality, Ave R is the average channel quality, and l-α and 1-j8 are the respective weighting factors. Rn and Ave Rn may be replaced with the amount of data that can be transmitted according to the line quality, not the line quality.

· Problems to be solved by the invention

In a wireless communication system in which a line is shared by multiple users, the scheduler selects a mobile station to be transmitted by multiple users based on the scheduling method, and performs adaptive modulation control according to the downlink line quality. carry out. For this reason, scheduling schemes have a significant impact on overall cell throughput. The Proportional Fairness method described above in the background art is superior in terms of improving throughput while maintaining fairness. The following issues still remain.

(1) The Proportional Fairness method makes it easy to select users whose line quality varies greatly. The Proportional Fairness method is a method that takes into account both fairness and throughput by using the ratio of the instantaneous value to the average line quality as an index, but the line quality that seems to be in a poor environment is intense, Easy to choose! / ,.

(2) The Proportional Fairness method is not a method that takes into account the data type. Even if the amount of data is the same, the transmission interval may be long for those that do not have real-time properties, such as e-mail, but the transmission interval needs to be shortened if real-time properties such as voice are required. . If the characteristics of such data types are not taken into account at all, it will be assigned frequently to those that do not require real-time characteristics so much, or conversely, they will not be assigned to those that have high real-time characteristics. Wireless resources cannot be used efficiently. (3) The Proportional Fairness method is not a method that takes into account the error rate for each CQI. In HSDPA, the amount of data to be transmitted is determined according to the line quality (CQI) so that the target error rate (block error rate = 0.1) is achieved. However, if the propagation environment varies depending on the location and time, the error rate at the mobile station varies depending on the terminal performance. In such a case, it is difficult for all users to make the error rate for each CQI uniform, that is, 0.1, and it is necessary to take this variation into consideration.

(4) The Proportional Fairness method is not a method that takes into account the error rate for each retransmission. In HSDPA, H-ARQ is implemented, and even if there is an error, the gain of error correction decoding is increased by effectively using the received data. If the number of retransmissions increases, the error rate Becomes smaller. Therefore, it is necessary to consider the error rate for each retransmission. By the way, the relationship between the number of retransmissions and the error rate (the relationship between the number of retransmissions and the gain) varies depending on the propagation environment. Therefore, it is necessary to take into account the relationship between the number of retransmissions and the error rate according to the propagation environment.

(5) The Proportional Fairness method is not a method that takes into account the uplink radio synchronization state. The selection candidate user is assumed to have established uplink synchronization, but it is possible to select a mobile station for which uplink synchronization is stable. That is, it is possible to select a mobile station that is in the forward and rearward protection state rather than in the fully synchronized state. The full synchronization state always indicates that the pilot synchronization has been established, and the forward protection state indicates that the pilot synchronization has been established at least once from the out-of-synchronization state, and then the state where the pilot synchronization has not increased by the number of forward protection stages. The protection state refers to a state in which pilot synchronization has not increased by the number of backward protection stages after pilot synchronization has been removed one or more times from the complete synchronization state. In the forward and backward protection state, the synchronization state is often unstable. In this case, the reception probability of HS-DPCCH data decreases and retransmission processing increases, so the cell throughput is low.

I will give you. Therefore, it is necessary to take the uplink synchronization state into consideration.

As described above, an object of the present invention is to provide a scheduling method and a base station apparatus that can solve the problems (1), (1) and (5) above and can achieve higher throughput based on the Proportional Fairness technique. is there.

Non-Patent Document 1: 3G TS 25.212 (3rd Generation Partnership Project: Technical Non-Patent Document 2: 3G TS 25.214 (3rd Generation Partnership Project: Technical Specification roup Radio Access Network; Physical layer procedures (FDD)) Non-Patent Document 3 RCS2001-291, pp.51-58, Mar.2002. Comparison of characteristics of scheduling methods focusing on the throughput of each user in high-speed downlink packets

In the first aspect of the present invention, the scheduler reflects the variance value of the channel quality or the fading frequency estimation result in the Proportional Fairness method. As a result, a mobile station with a severe change in channel quality or a high fading frequency is selected.

Further, in the second invention, the scheduler reflects the required transmission interval according to the data type in the Proportional Fairness method, so that the mobile station transmitting data with a short required transmission interval (data such as voice with high real-time property) is transmitted. Select with priority.

In the third invention, the scheduler reflects the error rate for each CQI in the Proportional Fairness method and preferentially selects a mobile station that has received a CQI with a low error rate.

In addition, in the fourth invention, the scheduler reflects the error rate for each number of retransmissions in the Proportional Fairness method, and preferentially selects a mobile station with the number of retransmissions with a low error rate.

In the fifth invention, the scheduler reflects in the Proportional Fairness method whether or not the mobile station is in a completely synchronized state, and preferentially selects a completely synchronized mobile station. According to the first invention, when the channel quality fluctuates drastically or the forging frequency is high, the uplink Z downlink reception characteristics tend to deteriorate. By selecting such a mobile station, the cell is selected. The overall error rate is lowered and the throughput is improved.

According to the second aspect of the present invention, an optimal line allocation according to the data type is performed by preferentially selecting a mobile station that transmits and receives data with a short required transmission interval and not allocating a line to a mobile station with a long required transmission interval. Is possible.

According to the third aspect, by preferentially selecting a mobile station that has received a CQI having a low error rate, the error rate of the entire cell is lowered and the throughput is improved.

According to the fourth invention, by preferentially selecting a mobile station having a low number of retransmissions with a low error rate, the error rate of the entire cell is lowered and the throughput is improved. According to the fifth aspect of the invention, the ACK / NACK reception probability is improved by preferentially selecting mobile stations that are reliably synchronized, and the number of retransmissions associated with DTX reception (no transmission) is reduced. Can improve throughput. Also, since the possibility of data transmission based on CQI with low reliability is reduced, the error rate increases when the amount of data is large compared to the line quality, and the transmission rate decreases and the throughput decreases when the amount of data is small The factor of decline can be eliminated.

Brief Description of Drawings

圆 1] It is a block diagram of the base station apparatus of the first embodiment.

[Figure 2] This is a scheduling process flow that takes into account the line quality fluctuation (VAR).

CQ

圆 3] It is a block diagram of the base station apparatus of the second embodiment.

[Fig. 4] This is a scheduling process flow that reflects the fading frequency fd.

[5] It is a block diagram of the base station apparatus of the third embodiment.

[Fig. 6] This is a scheduling process flow that takes into account the required transmission interval according to the data type.

7] It is a block diagram of the base station apparatus of the fourth embodiment.

[Fig. 8] This is the processing flow for calculating the error rate for each CQI by the error rate calculator.

9] An explanatory diagram of memory storage data of the error rate calculation unit.

[Figure 10] This is a scheduling process flow that takes into account the error rate for each CQI.

[11] FIG. 11 is a block diagram of a base station apparatus in a fifth embodiment.

12) This is a processing flow for calculating the error rate for each number of retransmissions by the error rate calculation unit.

[Fig. 13] This is a scheduling process flow that takes into account the error rate for each CQI.

14] It is a block diagram of the base station apparatus of the sixth embodiment.

FIG. 15 is a flowchart of scheduling processing according to the sixth embodiment in consideration of the wireless synchronization state. [16] It is a transition diagram between each synchronization state.

FIG. 17 is a configuration example of a W—CDMA mobile communication system.

FIG. 18 is an explanatory diagram of radio channels used for HSDPA.

FIG. 19 is an explanatory diagram of channel timing in HSDPA.

[Fig.20] This is a configuration example of the HSDPA system.

BEST MODE FOR CARRYING OUT THE INVENTION (A) First embodiment

FIG. 1 is a block diagram of the base station apparatus of the first embodiment. In the first embodiment, the scheduler 15 reflects the dispersion value of the line quality in the Proportional Fairness method.

The receiving unit 11 of the base station apparatus 10 performs amplification, band limitation, frequency conversion, orthogonal demodulation, AD conversion, and the like of the radio signal received by the antenna and inputs the result to the despreading unit 12.

The despreading unit 12 demodulates the DPCCH (dedicated physical control channel) and HS—DPCCH transmitted from the mobile station by despreading using the spreading code assigned to the mobile station (mobile terminal), and demodulates the DPCCH (dedicated The pilot signal obtained by demodulating the (physical control channel) is input to the channel estimation unit 13, and the HS-DPCCH demodulation signal is input to the ACKZCQI decoding unit 14. The channel estimation unit 13 estimates the channel using the pilot signal, and the ACKZCQI decoding unit 14 synchronously detects ACKZNACK and CQI based on the channel estimation value, performs error detection and correction processing, and sends ACKZNACK sent by HS-DPCCH , Decode and output CQI. Similarly, ACKZNACK and CQI sent from all mobile stations are decoded and input to scheduler 15.

The scheduler 15 calculates for each mobile station an index value based on the Proportional Fairness method and a variance value of the channel quality, corrects the index value based on the variance value of the channel quality, and stores data based on the corrected index value. Select the mobile station to send. Further, the scheduler 15 determines a transmission data amount, a spreading code, a modulation scheme, power, etc. based on the CQI information, and inputs it to the channel coding unit 16, spreading unit 18, and transmission unit 19. Further, the scheduler 15 requests the data destined for each mobile station from the radio base station controller RNC based on the data retention amount of the noffer unit (flow control).

The radio base station controller RNC holds data addressed to each mobile station received via the core network, and sends the data addressed to the requested mobile station to the base station 10 in response to a request from the scheduler 15. The buffer unit 17 of the base station stores the data addressed to each mobile station, which is also transmitted by the radio base station controller RNC, and the data addressed to the mobile station instructed by the instruction from the scheduler 15 is channeled in the requested block size. Input to coding section 16. The channel coding unit 16 adds a CRC code for each block to the input data addressed to the mobile station, and encodes it for each predetermined number of blocks, and the spreading unit 18 is instructed. The data is spread with the spreading code, and the transmitter 19 modulates the scheduler power with the instructed modulation method, and converts the frequency to a radio frequency and transmits it to the antenna power mobile station.

Figure 2 shows the scheduling process flow that takes into account the line quality fluctuation (VAR). First

CQ

Then, the channel estimation unit 13 estimates the phase rotation amount and amplitude variation amount in the radio space based on the DPCCH pilot signal (channel estimation) and inputs it to the ACKZCQI decoding unit 14 (step 101). The ACKZCQI decoding unit 14 detects ACKZNACK and CQI synchronously based on the channel estimation value, performs error detection and correction processing, decodes the HARQ reception result (ACK or NAC :) and CQI sent by HS—DPCCH, and scheduler Enter in 15. Similarly, HARQ reception results (ACK or NACK) sent from all mobile stations are decoded and input to scheduler 15 (step 102).

The scheduler 15 determines the transmission target data (new or retransmission) based on the HARQ reception result (ACK or NACK), and uses the following formula to determine the average line quality MEAN and the line quality fluctuation.

CQ

Calculate the quantity VAR (step 103).

CQ

MEAN = (1- T) X CQI + τ Χ ΜΕΑΝ (2)

CQ CQ

VAR = (1- τ) X (CQI-MEAN † + τ X VAR (3)

CQ CQ CQ

The line quality fluctuation amount VAR is a forgetting factor for the previous line quality and the CQI received this time.

CQ

The mean value MEAN is calculated using τ, and this CQI variance of this mean value MEAN force

CQ CQ

Is calculated using the forgetting factor τ.

Next, scheduler 15 uses this CQI, calculated MEAN, and VAR to calculate

CQ CQ

[Equation 2]

Cn (VASCQ) = Cn (PF) / VARcQ ⁽ ^{1.0 l} (5) is used to calculate the scheduling index value C taking into account the line quality variation (VAR).

Perform CQ n (VARCQ) (step 104). The index value in Eq. (4) is equivalent to the index value obtained by the Proportional Fairness method in Eq. (1). Scheduling index value: C is the value of Proportional Fairness n (VARCQ)

This is a value obtained by correcting the index value by the law with the line quality fluctuation (VAR). Also, in equation (5)

CQ

1-1 indicates the weighting of the line quality fluctuation amount for C. Optimize with consideration of the Kuta propagation environment and sector throughput.

Next, the scheduler 15 selects the mobile station with the highest correction index value C, and n (VARCQ)

Data is transmitted to the mobile station (step 105).

According to the first embodiment, by selecting a mobile station whose fluctuation in channel quality is significant, the error rate of the entire cell is lowered and the throughput is improved.

(B) Second embodiment

FIG. 3 is a block diagram of the base station apparatus of the second embodiment, and the same parts as in the first embodiment of FIG.

The code | symbol is attached | subjected. The different points are that a fusing frequency estimation unit 21 is provided, and that the scheduler corrects the index value based on the fading frequency and schedules based on the corrected index value. That is, in the second embodiment, the scheduler 15 reflects the fading frequency in the Proportional Fairness method.

Figure 4 shows the scheduling process flow with the fading frequency fd taken into account. First, channel estimation section 13 estimates the amount of phase rotation and amplitude fluctuation in the radio space (channel estimation) based on the DPCCH pilot signal, and inputs it to ACKZCQI decoding section 14 and fading frequency estimation section 21 (step 201). ). The fading frequency estimation unit 21 estimates the fading frequency fd from the time correlation of the channel estimation result and notifies the scheduler 15 (step 202). Various fading frequency estimation methods have been proposed. For example, there is a method (see Japanese Patent Application No. 2000-179609) that estimates the fading frequency using the time correlation of the pie signal.

Also, the ACKZCQI decoding unit 14 detects ACKZNACK and CQI synchronously based on the channel estimation value, performs error detection and correction processing, decodes the HARQ reception result (ACK or NAC :) and CQI sent on the HS-DPCCH. To scheduler 15 (step 203). Similarly, the HARQ reception result (ACK or NACK) sent from all mobile stations is decoded and input to the scheduler 15.

The scheduler 15 determines the data to be transmitted (new or retransmission) based on the HARQ reception result (ACK or NACK).

MEAN = (1- T) X CQI + τ Χ ΜΕΑΝ (6) The average line quality MEAN is calculated by (Step 204).

CQ

Next, scheduler 15 uses this CQI, calculated MEAN, and fading frequency.

CQ

Using fd,

[Equation 3]

To calculate the scheduling index value C with the fading frequency fd taken into account (step n (fd)

Pp 205). The index value in Eq. (7) corresponds to the index value by the Proportional Fairness method in Eq. (1), and the scheduling index value C is the index n (fd) by the Proportional Fairness method.

The value is corrected by fading frequency fd. In addition, in equation (8), 1− | 8 2 indicates the fading frequency weighting for the first n (PF), and is optimized in consideration of the propagation environment and sector throughput of the target sector.

Data is transmitted to the mobile station (step 206).

When the fuzzing frequency is high, the uplink Z downlink reception characteristics tend to deteriorate. However, according to the second embodiment, by selecting such a mobile station, the error rate of the entire cell is lowered, and the throughput is reduced. Will improve.

(C) Third embodiment

FIG. 5 is a block diagram of the base station apparatus according to the third embodiment. Components identical with those of the first embodiment shown in FIG. The difference is

(1) The transmission interval measurement unit 31 of each mobile station is provided,

(2) Host device power Receives the required transmission interval Txjnt and target minimum time difference Txjnt according to the type of transmission data for each mobile station,

min

(3) The scheduler corrects the index value based on the required transmission interval according to the data type, and schedules based on the corrected index value,

It is. That is, in the third embodiment, the scheduler 15 reflects the required transmission interval according to the data type in the Proportional Fairness method, and transmits data with a short required transmission interval (data such as voice with high real-time characteristics). Select a mobile station with priority. Figure 6 shows the scheduling process flow that takes into account the required transmission interval according to the data type. First, the channel estimation unit 13 estimates the phase rotation amount and amplitude fluctuation amount in the radio space based on the DPCCH pilot signal (channel estimation), and inputs it to the ACKZCQI decoding unit 14 (step 301). The ACKZCQI decoding unit 14 detects the ACKZN ACK and CQI synchronously based on the channel estimation value, performs error detection and correction processing, and receives the HARQ reception result (ACK or NACK) and CQI sent on the HS-DPCCH. Decrypt and input to scheduler 15 (step 302). Similarly, the HARQ reception result (ACK or NACK) sent by all mobile stations is decoded and input to the scheduler 15. The scheduler 15 determines transmission target data (new or retransmission) based on the HARQ reception result (ACK or NACK) and instructs the transmission interval measurement unit 31 to calculate the time difference of the transmission interval.

The transmission interval measurement unit 31 stores the previous transmission time for each mobile station in the built-in memory MEM and the required transmission interval Txjnt corresponding to the type of transmission data for each mobile station including the host device.

target

ing. When a time difference calculation is requested for a given mobile station from the scheduler, the transmission interval measuring unit 31 calculates a time interval Txjnt from the previous transmission time of the mobile station to the current time (step 303), and then the necessary transmission interval. Difference between Txjnt and calculated time interval Txjnt

target

Tx_Int_diff is the following formula

Tx— Int— diff = Txjnt -Txjnt (9)

target

Is calculated and input to the scheduler 15 (step 304).

Next, scheduler 15 is

MEAN = (1- T) X CQI + τ Χ ΜΕΑΝ (10)

CQ CQ

To calculate the average line quality MEAN (step 305)

CQ

C = CQI / MEAN (11)

n (PF) CQ

Thus, the index value C in the Proportional Fairness method is calculated (step 306). Finger

n (PF)

Once the standard value C is obtained, the time difference Tx_Int_diff is compared with the minimum time difference Txjnt (step n (PF) min

307), Tx_Int_diff ^ If the minimum time difference is greater than Txjnt,

min

[Equation 4]

Cn (TxInt) = Cn (PF) / (Tx lilt target Tx— Int) "— ⁰³ ) (12) Then, the index value C is corrected (step 308) .T _x Jnt_diff¾S If the minimum time difference _Tx j _nt is smaller than n (PF) min,

[Equation 5] Cn (PF) ΖΤχ— Int _min (丄.) The index value C is corrected by (13) (step 309).

n (PF)

Equations (12) and (13) are values obtained by correcting the index value obtained by the Proportional Fairness method at the required transmission interval according to the data type. 1- β 3 is the weight of Tx Int diff to C

n (PF)

It is assumed that the optimization will be performed in consideration of the propagation environment and sector throughput of the target sector. Also, Txjnt takes Tx_Int_diff ^

min

This is for defining the minimum value of the mother, and is a positive value as small as possible.

Thereafter, the scheduler 15 calculates the correction index value C for all mobile stations, and

n (TxInt)

Select the mobile station with the largest characteristic value C and transmit data to that mobile station (step n (TxInt)

Up 310).

According to the third embodiment, an optimum line allocation according to the data type is selected by preferentially selecting a mobile station that transmits and receives data with a short required transmission interval and not allocating a line to a mobile station with a long required transmission interval. Is possible.

(D) Fourth embodiment

FIG. 7 is a block diagram of the base station apparatus according to the fourth embodiment. Components identical with those of the first embodiment shown in FIG. 1 are designated by like reference characters. The difference is

(1) An error rate calculation unit 41 for calculating the error rate of each value of CQI = 1-30 is provided,

(2) The upper device also receives the minimum block error rate BLER_CQI,

min

(3) The scheduler corrects the index value based on the error rate for each CQI, and schedules V based on the corrected index value,

It is. That is, in the fourth embodiment, the scheduler 15 reflects the error rate for each CQI in the Proportional Fairness method and preferentially selects a mobile station with a low error rate. FIG. 8 is a processing flow of error rate calculation for each CQI by the error rate calculation unit 41. Upon receiving notification from the ACK / CQI decoding unit 14 that the mobile station UE # n has been detected within the target cell range (step 401), the error rate calculation unit 41 uses the built-in memory MM1 (see FIG. 9 (A)). Block number TBnum (k = 1-30) and error for mobile station UE # n stored in

η, κ

The number ERRnum (k = 1-30) is initialized to 0 and the block error rate BLER_CQI

n, k

(k = 1 to 30) is initialized to the minimum block error rate BLER_CQI (Step 402 n, k min

405).

After that, it is confirmed that the mobile station UE # n exists in the cell area (step 406) .If it exists in the cell area, the first block among the multiple blocks transmitted in TTI (2mse at subframe interval) is transmitted. In response to this, it is determined whether or not ACK is received, NACK is received, or nothing is received (steps 407 to 408). The base station determines a TF (Transport Format) for each TTI based on the CQ I value received from the mobile station, and based on the TF! / Determine the number of bits per block.

If an ACK is received, the number of blocks TBnum corresponding to the CQI that is the basis of the TF decision in the TTI is counted up (step 409), and if a NACK is received, the TTI is added.

n, k

When the number of blocks TBnum corresponding to the CQI that is the basis of the TF decision is counted up,

n, k

In addition, the error number ERRnum is counted up (step 410). Nothing is received

n, k

In this case (DTX reception), the number of blocks TBnum and the number of errors ERRnum are not changed.

n, k n, k

Next, wait until TTI elapses (step 411), and if TTI elapses, execute the processing from step 406 onward, and the number of blocks TBnum and error of CQI = 1-30 in mobile station UE # n

Obtain n, k number ERRnum and save in memory MM1.

n, k

Figure 10 shows the scheduling process flow that takes into account the error rate for each CQI.

First, the channel estimation unit 13 estimates the amount of phase rotation and amplitude fluctuation in the radio space based on the DPCCH noise signal (channel estimation), and inputs it to the ACKZCQI decoding unit 14 (step 451). The ACKZCQI decoding unit 14 is based on the channel estimation value! /, Synchronously detects ACKZNACK and CQI, performs error detection and correction processing, and decodes the HARQ reception result (ACK or NACK) and CQI sent on the HS—DPCCH And input to the error rate calculation unit 41 (step 452).

The error rate calculation unit 41 stores the number of blocks TBnum and the number of errors ERRnum according to CQI. Read from MM1

BLER— CQI = ERRnum / TBnum (14)

n, k n, k n, k

To calculate the block error rate BLER CQI according to the current CQI and

n, k

ACK / NACK and CQI are input to scheduler 15 (step 453).

MEAN = (1- T) X CQI + τ Χ ΜΕΑΝ (15)

CQ CQ

To calculate the average line quality MEAN (step 454). Next, the following formula

CQ

C = CQI / MEAN (16)

n (PF) CQ

Based on the above, the index value C in the Proportional Fairness method is calculated (step 455). Finger

n (PF)

If the standard value C is obtained, the block error rate BLER CQI and the minimum error rate BLER CQI n (PF) n, k

(Step 456) and if BLER.CQI is greater than min error rate BLER_CQI by min n, k min

[Equation 6]

_{Cn (PF) XBLER_CQI n, k} (1. 4) by (17), corrects the index value C (step 457), the minimum error rate BLER CQI is

n (PF) n, k

If it is smaller than BLER.CQI,

min

[Equation 7]

^{4) The} index value C is corrected according to (18) (step 458).

n (PF)

Eqs. (17) and 18) are the values obtained by correcting the index value by the Proportional Fairness method with the error rate for each CQI! / 1- β 4 is the weight of BLER CQI for C

n (PF) n, k

The optimization is performed in consideration of the propagation environment of the target sector and the sector throughput. BLER.CQI specifies the minimum value of the denominator considering the case of BLER_CQI force.

min n, k

A positive value that is as small as possible.

Thereafter, the scheduler 15 calculates the correction index value C for all mobile stations, and corrects it.

n (BLER CQl) Select the mobile station with the largest index value C and send data to that mobile station n (BLER_CQI)

(Step 459).

According to the fourth embodiment, by preferentially selecting a mobile station that has transmitted a CQI with a low error rate, the error rate of the entire cell is reduced and the throughput is improved.

(E) Fifth embodiment

FIG. 11 is a block diagram of the base station apparatus in the fifth embodiment, and the same parts as those in the first embodiment of FIG. The difference is

(1) Number of retransmissions = 1-1 There is an error rate calculation unit 51 for calculating the error rate of each value of 15,

(2) The minimum block error rate BLER_transmit is received from the host device.

min

(3) The scheduler corrects the index value based on the error rate for each retransmission, and schedules based on the corrected index value,

It is. That is, in the fifth embodiment, the scheduler 15 reflects the error rate for each number of retransmissions in the Proportional Fairness method and preferentially selects a mobile station with a low error rate. It is a processing flow of rate calculation. When the ACK / CQI decoding unit 14 receives a notification that the mobile station UE # n has been detected within the target cell range (step 501), the error rate calculation unit 51 uses the built-in memory MM2 (see FIG. 9B). ACKnum (k = 1-15) and NACK for error rate calculation of mobile station UE # n stored in

η, κ

Number NACKnum

(k = l 1 15) is initialized to 0, and the block error rate BLER_transmit (k = l n, k n, k 1 15) is initialized to the minimum block error rate BLER_transmit (step 502-50).

min

Five).

After that, it is confirmed that the mobile station UE # n exists in the cell area (step 506) .If it exists in the cell area, the first block of the multiple blocks transmitted in TTI (2mse at subframe interval) is transmitted. It is determined whether the power of receiving ACK, the power of receiving NACK, or nothing is received (steps 507 to 508).

If ACK is received, ACKnum is counted up according to the number of retransmissions (step 509 ), If NACK is received, NACKnum is counted up according to the number of retransmissions

n, k

510). If nothing is received (DTX reception), ACKnum, NACKnum

Do not change n, k n, k.

Next, wait until TTI elapses (step 511), and when TTI elapses, execute the processing from step 506 onward, and the number of retransmissions of mobile station UE # n = 1 1 15 ACKnum,

n, k

Find NACKnum and store it in memory MM2.

n, k

Figure 13 shows the scheduling process flow that takes into account the error rate for each CQI.

First, the channel estimation unit 13 estimates the phase rotation amount and amplitude fluctuation amount in the radio space based on the DPCCH noise signal (channel estimation), and inputs it to the ACKZCQI decoding unit 14 (step 551). The ACKZCQI decoding unit 14 is based on the channel estimation value! /, Synchronously detects ACKZNACK and CQI, performs error detection and correction processing, and decodes the HARQ reception result (ACK or NACK) and CQI sent on the HS—DPCCH And input to the error rate calculation unit 41 (step 552).

The error rate calculation unit 51 sends ACKnum and NACKnum according to the number of retransmissions from the memory MM2.

n, k n, k

Read, following formula

BLER—transmit = NACKnum / (ACKnum + NACKnum) (19)

n, k n, k n, k n, k

The block error rate BLER transmit corresponding to the current number of retransmissions is calculated by

n, k

The error rate, ACK / NACK, and CQI are input to the scheduler 15 (step 553).

MEAN = (1- T) X CQI + τ Χ ΜΕΑΝ (20)

CQ CQ

To calculate the average line quality MEAN (step 554). Next, scheduler 15

CQ

Next formula

C = CQI / MEAN (21)

n (PF) CQ

Based on the above, the index value C in the Proportional Fairness method is calculated (step 555).

n (PF)

Once index value C is obtained, scheduler 15 determines block error rate BLER transmit and

n (PF) n, k Compared with the minimum error rate BLER_transmit (step 556), BLER.transmit Is greater than the minimum error rate BLER_transmit,

[Equation 8]

^{5) The} index value C is corrected according to (22) (step 557), and BLER transmit is the minimum error rate.

n (PF) n, k

If it is smaller than BLER.transmit, then

[Equation 9]

C _n (BLER_transmit) = C _n (PF) / BLER_transmitmin ^(l "^{& 5) The} index value C is corrected by (23) (step 558).

n (PF)

Equation (22) [23] is the value obtained by correcting the index value by the Proportional Fairness method with the error rate for each retransmission. 1- β 5 is the weight of BLER transmit for C

n (PF) Indicates n, k addition, and is assumed to be optimized in consideration of the propagation environment and sector throughput of the target sector. Also consider the case where BLER_transmit becomes BLER_transmit power.

min n, k

In order to define the minimum value of the denominator, the positive value is as small as possible.

Thereafter, the scheduler 15 calculates the correction index value C for all mobile stations and compensates for it.

n (BLER_transmit)

Select the mobile station with the largest positive index value C and send data to that mobile station.

n (BLER_transmit)

(Step 559)

According to the fifth embodiment, by preferentially selecting a mobile station having a low number of retransmissions with a low error rate, the error rate of the entire cell is lowered and the throughput is improved.

(F) Sixth embodiment

FIG. 14 is a block diagram of the base station apparatus according to the sixth embodiment. Components identical with those of the first embodiment shown in FIG. The difference is

(1) A synchronization state monitoring unit 61 that monitors the uplink radio synchronization state of the mobile station and inputs the monitoring result to the scheduler 15 is provided.

(2) A synchronization state storage unit 62 for storing the synchronization state of each mobile station is provided,

(3) The scheduler performs scheduling in consideration of the radio synchronization state of the mobile station. The synchronization status monitoring unit 61 is a dedicated physical control channel DPC sent from the mobile station. Use the pilots included in the CH to monitor the power established and out of sync. That is, since the pilot is a known pattern, the received pilot and the known pilot are compared, and it is determined that the differential force is established, the synchronization is established, and if the difference is large, the synchronization is lost. Since this difference corresponds to the channel estimation value, the synchronization state monitoring unit 61 monitors the synchronization state based on the channel estimation value.

In the sixth embodiment, the scheduler 15 preferentially selects a mobile station in a completely synchronized state, and selects a UE in a forward and backward protected state only when there is no mobile station in a completely synchronized state. FIG. 15 shows a scheduling process flow of the sixth embodiment that takes into account the wireless synchronization state. MAX_UE_SEL is the number of selectable mobile stations. The number of mobile stations that can be selected is generally determined by the remaining power and code resources. Since the algorithm is not mainly described here, the number of mobile stations that can be selected is determined by some method. It is assumed that a mobile station is selected using this scheduling method.

Synchronization state monitoring 61 monitors whether all mobile stations UE # n (n = l-N) existing in the target cell are in full synchronization or forward / backward protection.

UE_SYNC [kl] = UE # n

And if it is in the front 'rear protection state'

UE.NOSYNC [k2] = UE # n

(Steps 601 to 608). FIG. 16 is a synchronization state transition diagram, and the synchronization state storage unit 62 stores whether the mobile station is in an out-of-synchronization state, a forward protection state, a complete synchronization state, or a backward protection state.

• Out-of-synchronization state: A state in which the mobile station belongs first, and communication with this mobile station is not possible. When synchronization is established even once, it shifts to the forward protection state.

• Forward protection state: Communication with the mobile station is possible before the transition to the fully synchronized state. When synchronization is established N1 times continuously, it shifts to the complete synchronization state, and once synchronization is lost, it shifts to the synchronization loss state. N1 is set to the optimum value according to the external environment such as the propagation environment and the characteristics of the equipment.

• Completely synchronized state: A state where communication with a mobile station is possible stably. If synchronization is lost even once, it will shift to the backward protection state. • Backward protection state: Communication with the mobile station is possible at the stage where there is a possibility of going out of synchronization. N2 times (determined by the system) If synchronization is lost continuously, it will be out of synchronization, and once synchronization is established, it will transition to full synchronization. N2 is set to an optimum value according to the external environment such as the propagation environment and the characteristics of the equipment.

[0020] In a state in which the synchronization state of each mobile station is stored in the synchronization state storage unit 62, the channel estimation unit 13 calculates the phase rotation amount and amplitude fluctuation amount in the radio space based on the DPCCH pilot signal. Estimate (channel estimation), and notify the ACKZCQI decoding unit 14 of the estimation result

The ACKZCQI decoding unit 14 decodes ACKZNACK and CQI, and transmits them to the scheduler 15. The scheduler 15 determines transmission target data (new or retransmission) based on the HARQ reception result (ACKZNACK).

Next, scheduler 15 uses the decrypted CQI to

MEAN = (1- T) X CQI + τ Χ ΜΕΑΝ (24)

CQ CQ

To calculate the average line quality MEAN and

CQ

C = CQI / MEAN (25)

n (PF) CQ

Calculate the index value C in the Proportional Fairness method. After that, do the same

n (PF)

Calculate index value C for all target mobile stations.

n (PF)

At this time, the mobile station that is subject to the calculation of C is determined by comparing the total number of UEs K1 stored in UE_SYNC [kl] with the MAX_UE_SEL. That is,

n (PF)

If Kl ≥ MAX_UE_SEL, only the mobile stations stored in UE_SYNC [kl], that is, the mobile stations in the fully synchronized state are targeted. On the other hand, if K1 <MAX_UE_SEL, all mobile stations are targeted (mobile stations stored in UE_SYNC and UE_NOSYNC, respectively).

[0021] When the calculation of index values of all target mobile stations is completed, the scheduler 15 selects a mobile station according to the lower processing flow (steps 701 to 704) in FIG. In other words, until k reaches the mobile station selectable number (MAX_UE_SEL) or until the total number of mobile stations stored in UE_SYNC is reached, select from the mobile stations in the synchronized state UE_SYNC in descending order of C.

n (PF)

To do. At this point, if the number of mobile stations selected has reached MAX_UE_SEL (YES in step 704) Then, the mobile station selection at that TTI is completed. Otherwise, go to step 801 and select the mobile station from the forward / backward protection state UE_NOSYNC.

That is, the scheduler 15 follows the processing flow in the lower part of FIG. 15 (steps 801 to 804) until k reaches the mobile station selectable number (MAX_UE_SEL), or all the movements where k exists in the target cell. Forward and backward protection until the number of stations (kl + k2) is reached

Select UE NOSYNC mobile stations in order from C high. At this point, the UE selection number

n (PF)

When MAX_UE_SEL is reached, or when all mobile stations belonging to the target cell are selected, UE selection at that TTI is terminated.

According to the sixth embodiment, by preferentially selecting mobile stations that are reliably synchronized, the reception probability of ACK / NACK is improved, and the number of retransmissions associated with DTX reception (no transmission) can be reduced. Throughput. In addition, since the possibility of data transmission based on CQI with low reliability is reduced, the error rate increases when the amount of data is large for the line quality! ], The transmission rate drop when the data volume is small! / ヽ and! /! Throughput reduction factor can be eliminated.

The power described above when applied to HDDPA The present invention is not limited to HDDPA that is powerful. Wireless data that transmits data from a network side to a predetermined mobile station via a wireless line shared by a plurality of mobile stations. It can be applied to a transmission system. In addition, in the above, the forces described for the individual embodiments can be combined as appropriate.

Claims

The scope of the claims

[1] In a scheduling method in a wireless data transmission system in which data is transmitted from a network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals, which mobile terminal is based on the received signal quality at each mobile terminal Calculate the index value for selecting a device,

Obtaining a variation rate of the quality, correcting the index value by the quality variation rate, and selecting a mobile terminal to send data based on the correction index value;

A scheduling method characterized by the above.

[2] In a scheduling method in a wireless data transmission system for transmitting data from a network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals, which mobile terminal is based on the quality of a received signal at the mobile terminal Calculate the index value of whether to select

Find the fading frequency at the mobile terminal,

The index value is corrected by the fading frequency,

Selecting a mobile terminal to send data based on the correction index value;

A scheduling method characterized by the above.

[3] In a scheduling method in a wireless data transmission system for transmitting data from a network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals, which mobile terminal is based on the quality of a received signal at the mobile terminal Calculate the index value of whether to select

Obtain the required transmission interval of data to be transmitted to the mobile terminal,

Correcting the index value by the required transmission interval;

Selecting a mobile terminal to send data based on the correction index value;

A scheduling method characterized by the above.

[4] Wireless data that transmits data from a network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals, and performs retransmission control when an error is detected in the data received by the mobile terminal In a scheduling method in a transmission system,

An indication of which mobile terminal to select based on the quality of the received signal at the mobile terminal. Calculate the standard value,

Calculating an error rate in the mobile terminal with the received signal quality;

The index value is corrected by the error rate,

Selecting a mobile terminal to send data based on the correction index value;

A scheduling method characterized by the above.

[5] The error rate is calculated based on signals indicating normal reception and abnormal reception transmitted from the mobile terminal.

The scheduling method according to claim 4, wherein:

[6] Radio data that transmits data from a network side to a predetermined mobile terminal via a radio line shared by a plurality of mobile terminals, and performs retransmission control when an error is detected in the data received by the mobile terminal In a scheduling method in a transmission system,

Based on the quality of the received signal at the mobile terminal, calculate the index value of which mobile terminal to select,

Calculate the error rate at the mobile terminal for each retransmission,

The index value is corrected by the error rate,

Selecting a mobile terminal to send data based on the correction index value;

A scheduling method characterized by the above.

[7] The error rate is calculated based on signals indicating normal reception and abnormal reception transmitted from the mobile terminal.

The scheduling method according to claim 6, wherein:

[8] In a scheduling method in a wireless data transmission system for transmitting data from a network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals, which mobile terminal is based on the quality of a received signal in the mobile terminal Calculate the index value of whether to select

Detect the uplink radio synchronization status of the mobile terminal,

A mobile terminal that transmits data is preferentially selected based on the index value from among the mobile terminals in synchronization.

A scheduling method characterized by the above.

[9] In a base station apparatus in a wireless data transmission system that transmits data to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals,

A receiver that receives data indicating the quality of the received signal at each mobile terminal from the mobile terminal;

Based on the received signal quality, an index value indicating which mobile terminal is to be selected for each mobile terminal is calculated, a variation rate of the received signal quality is obtained, and the index value is calculated based on the variation rate of the received signal quality. A scheduler that selects a mobile terminal that corrects and transmits data based on the correction index value;

A base station apparatus comprising:

[10] In a base station apparatus in a wireless data transmission system for transmitting data to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals,

Based on the received signal quality, an index value indicating which mobile terminal is selected for each mobile terminal is calculated based on the received frequency of the mobile terminal. A base station apparatus comprising: a scheduler that corrects the index value and selects a mobile terminal that transmits data based on the corrected index value.

[11] In a base station apparatus in a wireless data transmission system that transmits data to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals,

A transmission interval acquisition unit that acquires a necessary transmission interval of data to be transmitted to the mobile terminal; calculates an index value for selecting which mobile terminal for each mobile terminal based on the received signal quality; The index value is corrected and based on the corrected index value

V, a scheduler that selects the mobile terminal that sends data,

A base station apparatus comprising:

[12] Data is transmitted from the network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals. In a base station apparatus in a radio data transmission system that performs retransmission control when an error is detected in data received by a mobile terminal and transmitted,

An error rate calculation unit for calculating an error rate in the mobile terminal at the received signal quality; calculating an index value for selecting a mobile terminal based on the received signal quality; correcting the index value based on the error rate; A scheduler for selecting a mobile terminal to send data based on the correction index value;

A base station apparatus comprising:

[13] The error rate calculation unit calculates the error rate based on signals indicating normal reception and abnormal reception transmitted from a mobile terminal.

13. The base station apparatus according to claim 12, wherein

[14] From a network side to a predetermined mobile terminal via a wireless line shared by multiple mobile terminals

In a base station apparatus in a wireless data transmission system that transmits data and performs retransmission control when an error is detected in data received by a mobile terminal,

A receiving unit that receives data indicating the quality of a received signal at each mobile terminal and the number of retransmissions from the mobile terminal;

An error rate calculation unit for calculating an error rate in the mobile terminal for each retransmission,

An index value for selecting a mobile terminal is calculated based on the received signal quality of the mobile terminal, the index value is corrected based on the error rate, and a mobile terminal that transmits data is selected based on the correction index value! Scheduler to

A base station apparatus comprising:

[15] The error rate calculation unit calculates the error rate based on signals indicating normal reception and abnormal reception transmitted from a mobile terminal.

15. The base station apparatus according to claim 14, wherein

[16] In a base station apparatus in a wireless data transmission system that transmits data from a network side to a predetermined mobile terminal via a wireless line shared by a plurality of mobile terminals,

The data indicating the quality of the received signal at each mobile terminal is received from the mobile terminal. Nobube,

A synchronization detector for detecting the uplink radio synchronization state of the mobile terminal;

An index value for selecting a mobile terminal is calculated based on the received signal quality of the mobile terminal, and a mobile terminal that transmits data is preferentially selected from among the synchronized mobile terminals based on the index value. Scheduler,

A base station apparatus comprising: