JP4772533B2 - Data retransmission control method, system, and data retransmission control device - Google Patents

Description

  The present invention relates to a technical field of a data retransmission control method for improving system throughput in a communication system (particularly, a mobile radio data communication system), and further, a system using the retransmission control method and an apparatus for performing retransmission control, The present invention relates to the technical field of base stations and mobile stations (mobile terminals) constituting the system.

  Specifically, the slot timing (retransmission interval or retransmission time) for data retransmission from the transmitting side (mainly base station) to the receiving side (mainly mobile station) is dynamically controlled to efficiently use the slots. In particular, in the TDMA (Time Division Multiple Access) system, there is an effect of improving the system throughput. Also in the CDMA (Code Division Multiple Access) system, by controlling the retransmission time interval, the quality of the radio channel is improved and the system throughput is improved. In general, in a wireless system, traffic is managed for each sector, so improving the sector throughput is synonymous with improving the system throughput.

  In the current wireless system, the error data retransmission method for transmission data is such that when an error is detected on the mobile station side or when an error is detected but the error cannot be corrected, the NAK signal (resend The control response signal is urged to be transmitted to the transmission side. Actually, the NAK signal arrives at the base station, that is, after the base station detects that there is an error in the received data of the mobile station, data retransmission is performed after a fixed time interval.

In the example of the CDMA2000 1xEV-DO system, data retransmission is performed after an interval of 4 slots. Hereinafter, data retransmission from the transmission side (base station) to the reception side (mobile station) will be described using CDMA2000 1xEV-DO (EvolutionData Only is hereinafter abbreviated as EV-DO) as an example. The specifications of the EV-DO modulation method are as follows. QPSK, 8PSK, 16QAM is adopted for the downlink radio channel (from the base station to the mobile station), and BPSK, QPSK, 8PSK is adopted for the uplink radio channel (from the mobile station to the base station). The modulation method corresponds to the data transfer rate, and the strength of error tolerance is determined by the combination with the redundancy. The connection method is TDM (time division multiplexing) for downlink and CDMA (code division multiple access) for uplink.

  In each layer of EV-DO, various processes are performed in each layer in order to improve the quality of the radio channel. Layer 1 (physical layer) performs hybrid ARQ, acknowledgment (ACK), negative acknowledgment (NAK), error rate processing (channel quality information processing), and layer 2 (data link layer) performs retransmission control and radio link control. Layer 3 (network layer) performs control related to data reliability and radio resource control (radio channel control).

  In the EV-DO system, the radio service area is generally divided into a plurality of sectors, and the maximum transfer rate in each sector is about 2.4 Mbps (megabits per second). When there is one mobile station and the radio wave environment is good, the maximum transfer rate can be achieved. However, the transfer rate per unit decreases as the number of mobile stations increases. It goes without saying that the transfer rate decreases as the radio wave environment deteriorates. The deterioration of the radio wave environment will be described later.

  In the current EV-DO, TDM (Time Division Multiplexing) is adopted as the transmission method of the downlink radio channel, and therefore, in a certain sector, radio resources at a certain moment are concentrated on one mobile station (receiving side). For this reason, in the ARQ (automatic retransmission request) system in which an error in transmission data is detected at the reception side (mobile station) and retransmission is requested from the reception side (mobile station) to the transmission side (base station), the number of retransmission requests is If it increases, that is, if data errors occur frequently and the frequency at which the mobile station transmitting the NAK signal occupies the radio resource increases, the high-speed communication (reception) of other users (other mobile stations) will be hindered. In general, ARQ (Automatic Repeat Request) technology refers to retransmission processing in which data that could not be recovered by error correction in layer 1 is automatically sent again.

  In EV-DO, in order to further improve the efficiency of ARQ, hybrid-ARQ (combined automatic repeat request method) is adopted. EV-DO employs a method in which ARQ is incorporated between the base station and the mobile station in the process of iterative decoding of the error correction code (turbo code).

  Hybrid ARQ is a transmission function in layer 1 (physical layer). When reception fails in all slots, retransmission control is performed in layer 2 (data link layer). Incidentally, the turbo code has a strong error correction capability for transmission data and is superior to the convolutional code.

  Further, an N-channel SAW (Stop and Wait) system is employed for speeding up data. SAW is a type of data ARQ that returns an ACK signal from the receiving side to the transmitting side when data from the transmitting side is correctly received at the receiving side, and returns a NAK signal when a data error occurs. Patent Document 2 relating to SAW discloses a method in which when a NAK signal is received on the transmitting side, priority is given to other receiving stations until an ACK signal is received on the transmitting side for a specific frame on the receiving side. ing.

  However, this method processes N processes in parallel and independently, and therefore the order of data between processes is not guaranteed. This is a method in which the base station transmits data with a serial number attached to the header, and the mobile station arranges the order of the data according to the serial number and increases the amount of transmission per unit time. Even if the above-described method is adopted, if DRC (data rate control) that requires a data transmission rate from the mobile station to the base station is adopted, a high throughput can be realized in a place where the reception environment is good. However, in a bad place, the throughput is significantly reduced.

  As described above, even if the hybrid ARQ or the N-channel SAW method is used, it is inevitable that radio resources are still concentrated on one mobile station (receiving side). Repeatedly allocating radio resources to mobile stations with poor reception environment reduces sector throughput. Further, if the data retransmission interval is not properly controlled, the waiting time of other mobile stations becomes long, and the sector throughput is further reduced.

  Below, a prior art is demonstrated based on the figure of patent document 1. FIG. 51 shows a block diagram on the data receiving side, and FIG. 52 shows a block diagram on the data transmitting side. 51, on the data receiving side, a line monitoring unit 116 that outputs either the SIR measurement result or the packet arrival rate, and a data storage unit 117 that stores data for comparing the measurement results (stores the correspondence table of FIG. 53). ) And the data read from the data storage unit 117 and the measurement result, the two inputs are compared and the control state is output as a comparison unit 115, and the control state storage unit 113 stores the control state. And a control data generation unit 114 that receives the output of the control state storage unit 113 as an input.

  52, the control state storage unit 125 that stores the control state, and the control data and the data read from the data storage unit 126 (the correspondence table of FIG. 54 are stored) are used as inputs and the two inputs are compared. In addition, a comparison unit 123 that outputs data of the retransmission control cycle and a retransmission control cycle control 124 that controls the window size of the retransmission control are provided.

  FIG. 49 shows a chart on the data receiving side, and FIG. 50 shows a chart on the data transmitting side. When the number of received packets is greater than or equal to the threshold k and S65 on the receiving side in FIG. The measured value is compared S67 with the packet arrival rate vs. packet retransmission control periodic table. The retransmission control periodic table is shown in FIG.

  If the number of received packets is not greater than or equal to the threshold value k in step S65, the SIR is measured S68, and the measured value is compared S69 with the SIR vs. packet retransmission control periodic table. After the processing of step S67 or step S69, the control state is updated S70. Next, the control data of the retransmission control cycle is transmitted S71.

  In FIG. 50, the period control data for retransmission control is received S72, and the control state is updated S73. The control data is compared S74 with the retransmission cycle pair control state table, and the retransmission control cycle is updated S75.

  The retransmission control periodic table is shown in FIG. In the method of measuring the packet arrival rate and SIR as described above, and further changing the retransmission interval using a correspondence table of retransmission control periods prepared in advance, the presence of other mobile stations and the traffic that changes with time are taken into account. It was difficult to improve the sector throughput.

None of the prior art has proposed a method for dynamically changing the error rate and the retransmission interval.
JP 2002-271303 A Republished W02003 / 032566

  In order to improve the total throughput of a plurality of users in a sector of a radio system (especially a mobile radio system), the present invention efficiently performs retransmission control when a data error occurs due to the poor radio wave environment of the user (mobile station). It is to be implemented. In EV-DO, a TDM (Time Division Multiplexing) method is adopted for the downlink radio channel, and therefore radio resources for a certain period of time are concentrated on one mobile station (receiving side) in a certain sector. For this reason, errors in transmission data are frequently detected at the mobile station (reception side), the number of requests for data retransmission from the mobile station (reception side) to the base station (transmission side) increases, and other mobile stations ( Interfering with high-speed communication (reception) of other users) has been a problem. In addition, the constant use of the control notification channel (frequency channel) is contrary to the effective use of radio resources, which degrades the radio wave environment in the sector (increases the noise level) and decreases the throughput. It was.

  In the method using the correspondence table described in the technical background described in Patent Document 1 (shown in FIGS. 53 and 54), when the radio wave environment of the mobile station (reception side) is poor (SIR is low), the downlink data The retransmission time interval has been shortened, the number of retransmissions has increased, and the probability that a large number of mobile stations have been waiting has increased. SIR represents a desired wave received power to interference power ratio. In addition, when the correspondence table of Patent Document 1 is used, when the electric field strength varies greatly due to fading or the like and the radio wave environment is bad, it is necessary to frequently notify the change of the retransmission time interval using the notification channel. Wireless resource usage efficiency was impaired. As described above, it is difficult to improve the sector throughput when the conventional technique is used.

This invention is made | formed in view of said subject, and has the following means.
The data retransmission control method according to the present invention is a data retransmission control method in which an error in transmission data is detected on the reception side and retransmission is requested from the reception side to the transmission side. When the transmission side notifies the reception side of the interval and an error occurs on the reception side, the transmission side retransmits the transmission data after the notified retransmission interval in response to the reception of the NAK signal from the reception side. When the estimated error rate on the receiving side is below a predetermined level on the transmitting side, the retransmission control notification channel is released without notifying the retransmission interval using the retransmission control notification channel, A retransmission interval based on a predetermined condition is used, and when the estimated value of the error rate reaches a predetermined level or more, it responds to traffic using the notification channel for retransmission control. And notifying a retransmission interval.
The estimated value of the error rate is divided every time a predetermined number of transmission data is transmitted, with the predetermined number of data transmitted as a denominator and the number of retransmission data retransmitted based on a request method from the receiving side as a numerator. The calculation result is an estimated error rate on the receiving side.
A request method from the receiving side operates in a Stop and Wait ARQ method or a Selective Repeat ARQ method.
It further comprises transmission data number counting means, retransmission data number counting means, and error rate calculation means.
It further comprises transmission frame number counting means, retransmission frame number counting means, and error rate calculation means.
It further comprises transmission packet number counting means, retransmission packet number counting means, and error rate calculation means.
An error rate sampling means and an error rate change rate calculation means are further provided.
The retransmission interval is a slot interval or a time interval.
Different retransmission intervals are defined in advance according to the data rate of transmission data, and when a data error occurs, retransmission data is transmitted after the retransmission interval according to the transmission data rate at that time.
A data retransmission control system according to the present invention includes a base station and at least one mobile station, and is a retransmission control system that notifies a retransmission interval using a notification channel for retransmission control, the service area of the base station The data retransmission interval is calculated based on the traffic in the mobile station, the data retransmission interval is notified in advance to a second mobile station newly registered or handed over in the service area, and the estimated error rate in the mobile station is When a predetermined level or less is reached, the retransmission control notification channel is released, and a retransmission interval according to a predetermined condition is used. When the estimated error rate reaches a predetermined level or more, The retransmission interval is notified according to traffic using the notification channel for retransmission control.
A data retransmission control apparatus according to the present invention is provided in a base station, and performs retransmission control of data. The data retransmission control apparatus calculates a data retransmission interval based on traffic in a service area of the base station, and newly adds the service The data retransmission interval is notified in advance to the mobile station that has registered or handed over the location in the area, and the data retransmission interval is notified when the estimated error rate of the mobile station in the service area reaches a predetermined level or less. In this case, a retransmission interval based on a predetermined condition is used, and when the estimated value of the error rate reaches a predetermined level or more, the data retransmission interval is notified.

  The time interval dynamically changes, for example, a slot interval, a packet interval, a frame interval, a block interval, and the like. Also included are sub-slot intervals, sub-packet intervals, sub-frame intervals, sub-block intervals, and the like that further dynamically change the time interval in detail. Further, a fine time interval other than the above-described interval may be used. This is because the various time intervals are freely defined by the wireless system and may be selected according to the wireless system.

  Subsequently, in order to notify the retransmission interval in advance, it is necessary to manage traffic on the base station side. The traffic is defined by the data amount per second in the sector including not only data but also packet data by error retransmission control such as ARQ. The unit is bps (bits per second). As an example, when the existing A mobile station, B mobile station, and C mobile station are performing data communication of 1.2 Mbps, 0.6 Mbps, and 0.3 Mbps without any data error in the sector, the sum of 2 .1Mbps is traffic. By using the traffic as a variable and calculating using a calculation formula, the retransmission interval can be dynamically determined.

  In addition to the above, in order to determine the retransmission interval in advance, there is also a method of notifying the retransmission interval from the base station to the mobile station according to a predetermined condition (standard or negotiation at the start of communication).

  A specific data retransmission control method uses a notification channel for retransmission control in an ARQ (automatic retransmission request) method in which an error in transmission data is detected on the reception side and retransmission is requested from the reception side to the transmission side. Retransmission interval (slot interval or time interval) is notified from the transmission side to the mobile station that newly entered the sector with the retransmission interval calculated based on the traffic in the sector, and an error occurred on the reception side In this case, in response to receiving a NAK signal (control response signal for prompting retransmission) from the reception side, the transmission side retransmits the same data as the transmission data after the retransmission interval previously notified to the reception side by the transmission side. .

  In FIG. 1, the transmission side and the reception side can be either a base station or a mobile station. However, in a mobile data communication system, the base station is frequently used as a transmission side and the mobile station is a reception side. I will explain. The EV-DO base station has a maximum transfer rate of 2.4 Mbps per sector with three sectors as service areas. In EV-DO, PER (packet error rate, hereinafter referred to as error rate) is used as the error rate at the mobile station (reception side).

  As the error rate, BER (bit error rate), BLER (block error rate), FER (frame error rate), and the like are used as an index of error rate by various wireless communication systems. When the error rate is below a predetermined level, the notification channel is released without notifying the retransmission interval from the transmission side to the reception side using the notification channel for retransmission control. Thereby, radio resources can be used effectively.

  When the error rate reaches a predetermined level or higher, transmission is performed at a lower transmission rate than the previous time. Next, when the error rate reaches a predetermined level or higher, the frequency channel is changed from the previous one. Changing the frequency channel corresponds to changing the distance between the base station and the mobile station, can improve fading due to multipath, and is effective in improving the error rate. Finally, power control is performed. Increasing transmission power improves the error rate and improves the throughput for a desired mobile station. However, since leakage radio wave energy to adjacent sectors and adjacent service areas is increased, it is necessary to increase power to a minimum.

  Further, in order to improve the radio wave environment in the sector, when the error rate is below a predetermined value, the notification channel is released without notifying the retransmission interval from the transmission side to the reception side. When the error rate reaches a predetermined level or more, the retransmission interval is notified using the notification channel.

  Next, depending on the data rate requested from the receiving side to the transmitting side, different retransmission intervals are defined in advance using a calculation formula, and when a data error occurs, the DRC (data rate control) signal at that time is defined. The retransmission data is transmitted after the corresponding retransmission interval.

  Next, when the mobile station (reception side) is BUSY (busy: for example, when using Internet browsing, games, etc.), the data transmission side, after the BUSY state ends, the mobile station NACK signal is transmitted from the base station to the base station.

  Next, when an error is detected on the data receiving side and the data is retransmitted from the transmitting side, it is retransmitted at a lower data rate than the previous transmission, or retransmitted with a modulation scheme that is stronger in error tolerance than the previous transmission. Or is retransmitted on a frequency channel different from the previous time, or transmitted with higher power than the previous time. In EV-DO, the data rate substantially corresponds to the modulation method, and is 16QAM, 8PSK, and QPSK in order from the highest efficiency.

  Further, the present invention estimates the error rate on the receiving side from the number of retransmitted data with respect to the number of transmitted data in a transmitting side apparatus (base station apparatus) of a wireless data communication system using an ARQ (automatic retransmission control) method during data transmission. .

  Next, at the time of data transmission, the error rate estimation can also be realized by measuring the error rate of the reception data on the transmission side and estimating the error rate as the error rate on the reception side.

  The error rate uses BER (bit error rate), PER (packet error rate), or FER (frame error rate) as an index.

  In the data transmission, the means for checking the error of the received data on the transmission side uses a parity check or CRC (Cyclic Redundancy Code) check. If the error can be detected and corrected, the parity check or CRC The error rate after correcting the error by the check is used as the estimated error rate.

Next, the base station includes transmission packet number counting means, retransmission packet number counting means, and PER (packet error rate) estimation calculation means.
Further, the base station includes transmission frame number counting means, retransmission frame number counting means, and FER (frame error rate) estimation calculation means.

  In addition, an error rate change rate calculating unit that samples an error rate estimated value and predicts a change in which the error rate change rate is calculated using at least one of the sampling values is provided.

  There are various error rates depending on the radio communication system. In the present invention, BER (bit error rate), FER (frame error rate), and PER (packet error rate) are used for error rate estimation, but the block error rate is a similar concept. It is obvious to those skilled in the art that the present invention can also be applied.

  According to the data retransmission control method of the present invention configured as described above, the following effects can be obtained.

  First, the number of steps during retransmission control can be reduced by notifying the mobile station of the retransmission interval (retransmission timing, retransmission cycle) in advance.

  That is, when a retransmission request is notified to the base station, data can be retransmitted promptly. It is possible to reduce the waiting time until the specified retransmission interval timing, and it is possible to eliminate the waiting time when the traffic is low or when there is no other user (mobile station). Furthermore, since the retransmission timing is known, processing other than data communication can be performed on the mobile station side.

  Further, when the error rate is low, the radio resource can be used effectively by releasing the notification channel or omitting the notification of the retransmission interval. In addition, since the retransmission interval is managed by the base station, the probability that it overlaps with the data retransmission request of another user (mobile station) can be reduced, the radio wave environment can be kept good, and the throughput is further improved.

  The reason why the radio wave environment can be improved by opening the notification channel is as follows. The notification channel belongs to a frequency channel, and the frequency channel has a band. Similarly, the communication channel has a bandwidth. A notification channel and a communication channel are arbitrarily assigned from the base station to the mobile station. When the channel is used, electromagnetic wave energy at both ends of the channel leaks to adjacent frequency channels.

  Opening the notification channel temporarily increases the number of vacant channels, can reduce radio waves leaking to the communication channel, and improve the radio wave environment.

  Further, in the wireless data communication system, it is easy to quickly control various parameters related to data communication by estimating the error rate on the reception side on the transmission side. For example, when an error is detected in the CRC check on the data receiving side and the data is retransmitted from the transmitting side, the data is retransmitted at a lower transmission rate than the previous transmission, or the modulation method is stronger in error tolerance than the previous time. Throughput can be improved by resending or resending on a frequency channel different from the previous one.

  First, a channel configuration common to all the embodiments will be described. The configuration of the notification channel for retransmission control will be described with reference to FIGS. 15 to 17 as common items in the best mode and each embodiment.

  In FIG. 15, the frequency channel 80 is divided into a common channel 81 and an individual channel 82. The frequency channel 80 corresponds to each frequency in the TDMA system, and corresponds to a spread spectrum frequency in the CDMA. The common channel 81 is a channel used in common for all mobile stations in the sector.

  The dedicated channel 82 is a channel used for control or communication after the mobile station establishes call setting, and is generally a channel that is continuously used until the call is terminated.

  The common channel 81 is further divided into a common control channel 83 and a common communication channel 84. The common control channel 83 can notify control information to mobile stations in a sector all at once.

  The common communication channel is a channel that can be used for information transmission by all mobile stations and base stations in the sector.

  The dedicated channel 82 is further divided into a dedicated control channel 85 and a dedicated communication channel 86. The dedicated control channel 85 controls only one mobile station in the sector. The dedicated communication channel 86 is used when communicating with a mobile station in a sector. The individual channel 82 can be used efficiently by multiplexing even the same frequency channel 80 by time division processing or encoding processing.

  The notification channel 87 in FIG. 16 is a generic term for the common control channel 83 and the individual control channel 85, and is a channel for notifying the mobile station of the retransmission interval, data rate, modulation method, transmission power, and the like. The notification channel 87 to be released during communication is mainly the individual control channel 85. By releasing the channel according to the error rate, it is possible to effectively use radio resources.

  If the error rate reaches a predetermined level or more while using the dedicated communication channel 86, the common control channel 86 or the dedicated control channel is set to control the retransmission interval. The data channel 90 is a general term for communication channels, and includes a common communication channel 84 and an individual communication channel 86. Each application is the same as that described for the frequency channel 80. This completes the description of the channel.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. 1 includes a data transmission device 5, a retransmission control device 6, and a data reception device 7. The data transmission device 5 transmits data at a variable data rate, a variable modulation scheme, and a variable transmission power. The data receiving device 7 receives data from the mobile station 2 and performs demodulation / decoding. The retransmission control device 6 classifies the data from the data receiving device 7 and performs traffic calculation, retransmission method determination, retransmission interval calculation, and the like. Details will be described later as the retransmission control device 6 in FIG.

  The mobile station in FIG. 1 includes a data receiving device 8, a retransmission control device 9, and a data transmitting device 10, and the data receiving unit 8 receives data from the base station, demodulates and decodes, and detects data errors. , Correct errors. The retransmission control device 9 calculates the error rate and notifies the base station 1 of the result. Also, a retransmission method is determined, and a data rate request is made to the base station 1. The data transmitter 10 transmits data at the variable data rate, modulation scheme, and variable power finally determined by the base station 1.

  From here, the retransmission control device 6 will be described with reference to FIG. The retransmission control device 6 includes a mobile station management unit 143, an error rate management unit 146, a data rate management unit 147, a transmission buffer 142, a traffic management unit 144, and a retransmission interval management unit 145. The mobile station management unit 143 counts the mobile stations registered in the sector and the number of mobile stations flowing into and out of the sector, and always knows the current number of mobile stations. Further, the mobile station grasps and manages whether or not the mobile station is BUSY. The error rate management unit 146 sequentially holds the latest error rate for each mobile station based on the notification from the mobile station. The data rate management unit 147 manages the data rate for each mobile station and the amount of data to be transmitted, which are determined by a request from the mobile station or the judgment of the base station. The transmission buffer 142 holds data to be transmitted to each mobile station according to an instruction from the data rate management unit 147.

  As described above, there are various error rates depending on various wireless communication systems, but since EV-DO performs data communication in units of packets, the relationship between the packet error rate and the retransmission interval in FIG. Will be described as an example. The traffic managed by the traffic management unit 144 includes not only data but also a packet by data retransmission control such as hybrid AQR.

  In the present invention, referring to the correspondence table of FIG. 53 of the prior art and the correspondence table of FIG. 54, the retransmission interval is dynamically determined using a calculation formula without performing steps such as changing the control state. Basically, the calculation formula may be such that the retransmission interval does not become zero.

  This is because it takes a finite time from when the mobile station transmits the NAK until the signal reaches the base station and the retransmission data reaches the mobile station. In the traffic and retransmission interval of FIG. 22, the calculation formula y = [7 / x] -1 is exemplified. [] Is a Gaussian symbol and represents the largest integer. The constants 7 and 1 in the calculation formula can be appropriately changed so that the calculation result becomes a value larger than 0. FIG. 6 shows a chart of a method for determining a retransmission interval.

  First, the intra-sector traffic is calculated S29, and then the retransmission interval corresponding to the traffic is calculated. The mobile station is notified of the calculated retransmission interval. The notified mobile station stays in the sector with the mobile station that newly entered the sector, and is notified to the mobile station that is not performing data communication using the notification channel 87.

  FIG. 23 shows a calculation formula y = [2.5x] +1 of the packet error rate and the retransmission interval.

  The calculation formula can also be appropriately changed so that the calculation result becomes a value larger than 0, similarly to the calculation formula of FIG.

  Although the packet error rate is shown in FIG. 23, other error rates may be used as appropriate. In each of the above two expressions, a constant is selected so that the retransmission interval is about 1 to several tens.

  The retransmission intervals in FIGS. 22, 23, and 24 are in units of slots. However, since one EV-DO slot is 1.666 ms (milliseconds), the number of slots is multiplied by 1.666 ms to be converted into time. It ’s fine.

  FIG. 2 is a chart for notifying the retransmission interval from the base station 1 to the mobile station A3 and the mobile station B4 using the notification channel. For simplicity, it is assumed that the amount of data to be transmitted from the base station has changed (traffic has changed) without considering the inflow mobile station and the outflow mobile station. The base station 1 notifies the retransmission interval T to the mobile station A3 and the mobile station B4.

  In FIG. 2, the horizontal axis is the time axis, and the common control channel 83 is used as the notification channel 87. (Thick arrow) The timing at which packet data (thin arrow) is sent from the base station 1 to each mobile station is shown. The NAK signal and the corresponding packet data are indicated by dotted lines.

  Data (1), (3), (5), (6), and (8) are packet data transmitted from the base station 1 to the mobile station A3, and data (5) of these data failed to receive data. Thus, it is received again at the retransmission interval S. Data (2), (4), and (7) are packet data transmitted from the base station 1 to the base station B4. The data (2) fails to receive data and is received again at the retransmission interval T. .

  In the example of FIG. 2, using the common control channel 83 as the notification channel 87, the same retransmission interval is notified to the two mobile stations at the same timing. However, if the dedicated control channel 85 is not released, Different retransmission intervals may be notified using the dedicated control channel. Different retransmission intervals may be notified from the base station 1 to the mobile station A3 and the mobile station B4 in advance.

  4 and 5 show detailed operations of the mobile station 2 and the base station 1. FIG. First, the base station 1 transmits a retransmission interval notification to the mobile station 2 in advance S19, and the mobile station 2 receives a retransmission interval notification S12. The mobile station 2 transmits a data request S13 to the base station 1, and the base station receives S20 the data request. The base station 1 transmits data S21 to the mobile station 2. The data causes an error due to propagation failure, and the mobile station receives the error data S14. Therefore, the mobile station transmits a NAK signal to the base station S15. The base station that receives the NAK signal S22 transmits S23 at the retransmission interval in which the request data is notified in advance. At this time, the mobile station waits for a retransmission interval S16. The mobile station that correctly receives the request data S17 transmits an ACK signal to the base station S18. The base station receives the ACK signal S24, and the series of data retransmission ends. The best mode for carrying out the present invention has been described above with reference to FIGS. 1 to 6, 22, and 23.

<First embodiment>
A method for changing various parameters will be described as a first embodiment. 7 to 11 are all effective methods for improving the throughput.

  7 is a notification channel releasing method, FIG. 8 is a transmission rate changing method, FIG. 9 is a modulation method changing method, FIG. 10 is a frequency channel changing method, and FIG. 11 is a power control method.

  First, a method for releasing the notification channel 87 will be described with reference to FIG. First, the error rate is measured S32 at the mobile station and notified to the base station 1. When the error rate is not below the predetermined level S33, the base station 1 notifies the mobile station of the retransmission interval via the notification channel S35. When the error rate is below a predetermined level S33, the notification channel is released S34 without notifying the retransmission interval. Thereby, the radio channel is released and the radio wave environment in the sector is improved.

  Next, a method for changing the transmission rate will be described with reference to FIG. An error rate is notified from the mobile station to the base station S40. When the error rate is not lower than the predetermined level S41, the transmission rate is lowered from the previous time, and the transmission S42 is performed. When the error rate is lower than the predetermined level S41, the same as the previous time. Transmission S43 is performed at the transmission rate.

  Next, a modulation method changing method will be described with reference to FIG. The error rate is notified from the mobile station to the base station S44, and when the error rate is not lower than the predetermined level S45, transmission S46 is performed with a modulation method having a stronger error resistance than the previous time. When the error rate is below a predetermined level, transmission S47 is performed using the same modulation method as the previous time.

  Next, a frequency channel changing method will be described with reference to FIG. An error rate is notified from the mobile station to the base station S48, and when the error rate is not less than a predetermined value S49, the error rate is transmitted on a frequency channel different from the previous one. When the error rate is below a predetermined level, transmission S51 is performed at the same frequency as the previous time.

  Finally, a power control method will be described with reference to FIG. An error rate is notified from the mobile station to the base station S52. When the error rate is not lower than a predetermined level S53, transmission is performed at a transmission power higher than the previous time S54. When the error rate is lower than a predetermined level S53, the same power as the previous time is transmitted. Then, transmission S55 is performed.

  As described above, it is possible to improve the radio wave environment and improve the throughput by controlling various parameters with the threshold of the error rate.

<Second embodiment>
As a second embodiment, a retransmission method at a retransmission interval corresponding to a data request rate and a retransmission method at the timing of a NAK signal will be described based on FIG.

  First, in FIG. 12, the base station receives the data request rate from the mobile station S56, and transmits data S57 from the base station to the mobile station. When the base station receives the NAK signal S58, it retransmits data S59 to the mobile station at a predefined retransmission interval. The retransmission interval notification from the base station to the mobile station is omitted. FIG. 24 is a calculation formula showing the data rate and the retransmission interval. Formula y = [2.4 / x] The above formula does not become 0 because the denominator is the data rate.

  Whether or not the base station responds to the data request rate from the mobile station considers the error rate of the mobile station and the requested data amount. If the error rate is low, the request from the mobile station is accepted, but if the error rate is extremely high, the request is rejected.

  Next, the NAK signal transmission timing change will be described with reference to FIG. When data is transmitted from the base station to the mobile station but an error occurs in the mobile station S60, if the mobile station is not BUSY, the mobile station immediately transmits a NAK signal S62. When the mobile station is BUSYS 61, the mobile station holds the NAK signal S63. When the BUSY state ends, the mobile station transmits a NAK signal S64. As a result, the mobile station can receive data while it is ready for reception, without the base station transmitting data unnecessarily. Therefore, waste of radio resources can be prevented and the radio wave environment can be kept good.

<Third embodiment>
As a third embodiment, a case where various parameters are comprehensively used will be described with reference to FIG. In EV-DO, the data rate substantially corresponds to the modulation method, and therefore, description will be made using the data rate. When considering the modulation method, the data rate is associated with the modulation method.

  In step S105, transmission is performed at a data rate lower than the previous time with a modulation method having a stronger error resistance than the previous time. First, an error rate is notified from the mobile station to the base station S100, and when the error rate is not equal to or lower than a predetermined level, S101 is transmitted on a frequency channel different from the previous one. When the error rate is equal to or lower than S101, transmission S103 is performed using the same frequency channel as the previous time. If the error rate does not become equal to or lower than the predetermined S104 even if the frequency channel is changed in step S102, transmission is performed at a data rate S105 lower than the previous time. When the error rate is equal to or lower than a predetermined value S104, transmission is performed at the same data rate S106 as the previous time. If the error rate does not become equal to or lower than S107 even if the data rate is lowered in step S105, transmission S108 is performed with higher power than the previous time, and if the error rate is lower than the predetermined level, S107 is transmitted with the same power as the previous time. To do. This embodiment is an example in which parameters are managed strictly in detail.

<Fourth embodiment>
18 to 21 are diagrams for explaining a wireless system according to the present invention. FIG. 18 shows a state where the second mobile station 136 has flown into the first sector 133 in the service area due to location registration or handover. Since the number of mobile stations in the sector has increased, the retransmission control apparatus provided in the base station 131 calculates traffic and notifies the second mobile station and the mobile station 132 originally located in the first sector of the retransmission interval.

  FIG. 19 is a diagram showing a state in which the mobile station 132 in data communication in the first sector 133 moves, enters the shadow of the obstacle 137, and the error rate increases. In this case, the data rate of the mobile station may be managed by the method described in the first and third embodiments.

  FIG. 20 shows a mobile station that is being browsed, and shows a state in which a NAK signal is transmitted to the base station 131 and desired data is immediately received upon completion of the BUSY state.

  FIG. 21 is a diagram in which the mobile station 132 notifies the base station 131 of the error rate, and the mobile station 132 receives data corresponding to the error rate.

  Next, in the data retransmission control system described above, in order to efficiently perform data retransmission using the ARQ scheme that detects an error in transmission data and requests retransmission, the error rate on the reception side is estimated on the transmission side. An embodiment for efficiently performing data retransmission control will be described. In this data retransmission control, as described above, the receiving side obtains the error rate of the signal received at its own station, and does not acquire the error rate by notifying the transmitting side to the receiving side. The error rate of the device is estimated by the transmission side device (base station device), and retransmission control is performed quickly without waiting for notification of the communication status from the mobile station, thereby improving the throughput.

  First, a common data structure will be described with reference to the drawings. FIG. 46 shows a basic data structure. The header 60 includes an address part 30 and a control part 31. The data 61 includes an information part 32 and an FCS (frame check sequence) 33. The information part 32 consists of fixed length data, and the FCS 33 shows an example using parity (even / odd) check. FIG. 43 shows a horizontal parity check, which is a type of parity check. 0 and 1 in the solid line frame represent data, and 0 and 1 in the dotted line frame represent horizontal parity. Since the top row is 0, 1, 1, 0, the parity is 0 (even).

  FIG. 47 shows an example in which the information part 36 and the FCS 37 are defined as a frame 63 and a CRC (cyclic redundancy code) check is used for the FCS 37. For the CRC check, a generator polynomial F (x) = x ^ 16 + x ^ 12 + x ^ 5 + 1 is generally used.

  FIG. 48 shows details of the packet structure. The packet is divided into a header 64 and a payload 65. The header 64 includes a reception side address 38, a transmission side address 39, a sequence number 40, an information length 41, an ACK 42 (or NAK), and an FCS 43. The sequence number 40 is added in order to correctly grasp the arrival order of the packets when the packets do not reach due to an error or loss. The information length 41 indicates the length of the information 44 of the payload 65. The length of the information 44 is an arbitrary length. The ACK 42 is a signal transmitted from the receiving side to the transmitting side when the information 44 of the payload 65 is correctly received by the FCS 45. NAK is not shown, but is a signal sent from the receiving side to the transmitting side when it cannot be received correctly.

  The FCS is generally added to both the header and payload. Frame structures and data structures are often covered by a single FCS.

  The Stop and Wait ARQ method used in the present invention is a method of waiting for confirmation from the other party each time one packet is sent. Each time an error occurs in the transmission path, the receiving side device sends a NAK signal to the transmitting side device.

  The Selective Repeat ARQ method is a method in which several packets are forwarded from the transmission side device to the reception side device without confirmation. Each packet is numbered, and the transmission side device has an error according to the NAK signal from the reception side device. This is a method of retransmitting only the packets that become.

  It is obvious to those skilled in the art that various structures such as a frame structure, a data structure, a packet structure, and the like exist depending on the use of the communication system.

<Fifth embodiment>
FIG. 25 is a functional block diagram showing signal flow and signal transmission / reception on the transmission side (base station) 21 in the fifth embodiment. For simplicity, only the main part of error rate estimation is shown in the transmission system of the base station. The base station 21 includes transmission data 22, a transmission buffer 23, a transmitter 24, transmission control means 28, and error rate estimation means 20. Further, the error rate estimating means 20 comprises a retransmission data number counting means 201, a transmission data number counting means 202, and an error rate calculating means 203.

  According to the flowchart of FIG. 26, after the transmission data number counting step S111, the presence / absence of the number of retransmission data is determined in step S112, the number of retransmission data is counted in step S113, and the error rate is calculated in step S114. As described above, the error rate on the receiving side (mobile station) can be estimated on the base station side.

  Next, an actual error rate change will be described with reference to FIGS. 31 and 34 using calculation examples. This description is a method based on the Stop and Wait ARQ (automatic retransmission control) method. First, FIG. 31 shows a state in which data is sent from the transmission side to the reception side, data 1 is sent correctly, and data 2 is retransmitted because an error is detected and cannot be corrected on the reception side. As the transmission path, any one of a wired transmission path, a wireless transmission path, and a combination of a wired transmission path and a wireless transmission path is used according to the communication system.

  For the fifth embodiment, the number of data at that time is shown in FIG. 34 and calculated under the three conditions of A, B, and C. BER (bit error rate) of condition A. The unit of the number of data is bits. Condition A is when the length of the information part is fixed.

  Conditions B and C are not normally used, but are described in comparison with the packet communication in FIG.

  In condition A of FIG. 34, data 1 is 100 bits, data 2 is 100 bits, retransmission of data 2 is 100 bits, and data 3 is 100 bits. At this time, the total number of transmission data is 400 bits, the number of retransmission data is 100 bits, and BER = (100/400) × 100 = 25%.

  34, data 1 is 100 bits, data 2 is 50 bits, retransmission of data 2 is 50 bits, and data 3 is 100 bits. At this time, the total number of transmission data is 300 bits, the number of retransmission data is 50 bits, and BER = (50/300) × 100 = 16.7%.

  34, data 1 is 100 bits, data 2 is 50 bits, retransmission of data 2 is 50 bits, and data 3 is 50 bits. At this time, the total number of transmission data is 250 bits, the number of retransmission data is 50 bits, and BER = (50/250) × 100 = 20%.

<Sixth embodiment>
FIG. 27 is a functional block diagram showing signal flow and signal transmission / reception on the transmission side (base station) 21 in the sixth embodiment. For simplicity, only the main part of error rate estimation is shown in the transmission system of the base station. The base station includes transmission data 22, a transmission buffer 23, a transmitter 24, transmission control means 28, and error rate estimation means 20. Further, the error rate estimating means 20 comprises a retransmission frame number counting means 204, a transmission frame number counting means 205, and an error rate calculating means 203.

  According to the flowchart of FIG. 28, after the transmission frame number counting step S115, the presence / absence of the number of retransmission frames is determined in step S116, the number of retransmission frames is counted in step S117, and the error rate is calculated in step S118. As described above, the error rate on the receiving side (mobile station) can be estimated on the base station side.

  Next, the actual error rate change will be described with reference to FIGS. 32 and 35 using calculation examples. This description is a method based on the Stop and Wait ARQ (automatic retransmission control) method. FIG. 32 shows a state in which a frame is transmitted from the transmission side to the reception side, frame 1 is correctly transmitted, frame 2 is retransmitted because an error is detected and correction cannot be performed on the reception side.

  The number of data at that time is shown in FIG. 35 and is calculated under the three conditions of A, B, and C. FER (frame error rate) of condition A. The unit of the number of data is bits. Condition A is when the length of the information part is fixed. Condition B and condition C are not normally used, but are described for comparison with the packet of FIG.

  In condition A of FIG. 35, frame 1 is 256 bits, frame 2 is 256 bits, retransmission of frame 2 is 256 bits, and frame 3 is 256 bits. At this time, the total number of transmission data is 1024 bits and the number of retransmission data is 256 bits. FER = (1/4) × 100 = 25%.

  In condition B in FIG. 35, frame 1 is 256 bits, frame 2 is 128 bits, retransmission of frame 2 is 128 bits, and frame 3 is 256 bits. At this time, the total number of transmission data is 768 bits and the number of retransmission data is 128 bits. FER = (1/4) × 100 = 25%.

  In FIG. 35, condition C is 256 bits for frame 1, 128 bits for frame 2, 128 bits for retransmission of frame 2, and 128 bits for frame 3. At this time, the total number of transmission data is 640 bits and the number of retransmission data is 128 bits. FER = (1/4) × 100 = 25%.

<Seventh embodiment>
FIG. 29 is a functional block diagram showing signal flow and signal transmission / reception on the transmission side (base station) 21 in the seventh embodiment. For simplicity, only the main part of error rate estimation is shown in the transmission system of the base station. The base station includes transmission data 22, a transmission buffer 23, a transmitter 24, transmission control means 28, and error rate estimation means 20. Further, the error rate estimating means 20 comprises a retransmission packet number counting means 206, a transmission packet number counting means 207, and an error rate calculating means 203.

  According to the flowchart of FIG. 30, after the transmission packet number counting step S119, the presence / absence of the number of retransmission packets is determined at step S120, the number of retransmission packets is counted at step S121, and the error rate is calculated at step S122. As described above, the error rate on the receiving side (mobile station) can be estimated on the base station side.

  Next, an actual error rate change will be described with reference to FIGS. 33 and 36 using calculation examples. This description is a method based on the Stop and Wait ARQ (automatic retransmission control) method. FIG. 33 shows a state in which a packet is sent from the transmitting side to the receiving side, packet 1 is sent correctly, packet 2 is detected as an error, and packet 2 is retransmitted because it cannot be corrected on the receiving side.

  The number of data at that time is shown in FIG. 36 and is calculated under the three conditions of A, B, and C. This is the PER (packet error rate) of condition A. The unit of the number of data is bits. Condition A is when the length of the information part is fixed.

  36, packet 1 is 64 bits, packet 2 is 64 bits, retransmission of packet 2 is 64 bits, and packet 3 is 64 bits. At this time, the total number of transmission data is 256 bits and the number of retransmission data is 64 bits. PER = (1/4) × 100 = 25%.

  36, packet 1 is 64 bits, packet 2 is 32 bits, retransmission of packet 2 is 32 bits, and packet 3 is 64 bits. At this time, the total number of transmission data is 192 bits and the number of retransmission data is 32 bits. PER = (1/4) × 100 = 25%.

  In condition C of FIG. 36, packet 1 is 64 bits, packet 2 is 32 bits, packet 2 is retransmitted 32 bits, and packet 3 is 32 bits. At this time, the total number of transmission data is 160 bits, the number of retransmission data is 32 bits, and PER = (1/4) × 100 = 25%.

  When calculated based on the number of data, the error rate changes to 25%, 16.7%, and 20%, but when calculated based on the number of frames and packets, the number of transmitted data and the number of retransmitted data differ. However, the error rates may all be the same (25% in this calculation example).

  Next, an actual error rate change will be described with reference to FIGS. 37 to 42 using calculation examples. This description is based on a method of Selective Repeat ARQ (automatic retransmission control), and FIGS. 37 and 38, FIGS. 39 and 40, and FIGS. 41 and 42 correspond to each other.

<Eighth embodiment>
First, an eighth embodiment will be described with reference to FIGS. Data is continuously transmitted from the transmission side to the reception side, and the first four sets (up to the dotted line in FIG. 37) are transmitted together. An error that cannot be corrected in data 2 occurs on the transmission path, and the NAK is transmitted from the reception side. Only 2 are requested for retransmission. In this example, data 2 is retransmitted after the dotted line, and data 5 and data 6 are subsequently transmitted.

  FIG. 38 shows the bit error rate calculated under the three conditions A, B, and C. Condition A is an example in which the first four sets of data are all 100 bits. Since a 100-bit error has occurred in data 2, BER = (100/700) × 100 = 14.3%.

  Condition B is an example in which the first four sets of data are all 50 bits, a 50-bit error occurs in data 2, 50 bits are retransmitted, and 100 bits are transmitted as data 5 and data 6, respectively. BER = (50/450) × 100 = 11.1%.

  Condition C is that data 1 and data 2 are transmitted 100 bits each, and data 3 and data 4 are transmitted 50 bits each. The error in the transmission path is 50 bits in data 2.

  BER = (100/600) × 100 = 16.7%.

<Ninth embodiment>
A ninth embodiment will be described with reference to FIGS. 39 and 40. FIG. Frames are continuously transmitted from the transmission side to the reception side, and the first four sets (up to the dotted line in FIG. 39) are transmitted together. An error that cannot be corrected in frame 2 occurs on the transmission path, and a NAK is transmitted from the reception side. Only 2 are requested for retransmission. In this example, frame 2 is retransmitted after the dotted line, and frames 5 and 6 are subsequently transmitted.

  FIG. 40 shows the frame error rate calculated under the three conditions A, B, and C. Condition A is an example in which the first four sets of frames are all 256 bits. Since a 256-bit error has occurred in frame 2, FER = (1/7) × 100 = 14.3%.

  Condition B is an example in which the first four sets of frames are all 128 bits, a 128-bit error occurs in frame 2, 128 bits are retransmitted, and 256 bits are transmitted in frame 5 and frame 6, respectively. FER = (1/7) × 100 = 14.3%.

  Condition C is that 256 bits are transmitted in frames 1 and 2 and 128 bits are transmitted in frames 3 and 4. The error in the transmission path is 256 bits in frame 2. FER = (1/7) × 100 = 14.3%.

<Tenth embodiment>
A tenth embodiment will be described with reference to FIGS. 41 and 42. FIG. Packets are continuously transmitted from the transmission side to the reception side, and the first four sets (up to the dotted line in FIG. 41) are transmitted together. An error that cannot be corrected in the packet 2 occurs on the transmission path, and a NAK is transmitted from the reception side Only 2 are requested for retransmission. In this example, packet 2 is retransmitted after the dotted line, and packets 5 and 6 are subsequently transmitted.

  FIG. 42 shows the packet error rate calculated under the three conditions A, B, and C. Condition A is an example in which the first four sets of packets are all 64 bits. Since a 64-bit error has occurred in packet 2, PER = (1/7) × 100 = 14.3%.

  Condition B is an example in which the first four sets of packets are all 32 bits, a 32-bit error occurs in packet 2, 32 bits are retransmitted, and 64 bits are transmitted in packet 5 and packet 6, respectively. PER = (1/7) × 100 = 14.3%.

  Condition C is that packet 1 and packet 2 are transmitted 64 bits each, and packet 3 and packet 4 are transmitted 32 bits each. The error in the transmission path is 64 bits in packet 2.

  PER = (1/7) × 100 = 14.3%.

<Eleventh embodiment>
Next, an eleventh embodiment will be described. 44 is obtained by adding a sampling unit 209 and an error rate estimated value change rate calculating unit 208 to the error rate estimating unit 20 of FIG. The change rate calculation means 208 makes it possible to predict a change in error rate, and appropriate transmission parameters (data rate, modulation scheme, information length, transmission from the transmission side (base station) 21 to the reception side (mobile station), Transmission power etc.) can be selected.

  Hereinafter, the calculation in the error rate estimation means 20 will be described. When the estimated error rate at time T1 is E1, and the estimated error rate at time T2 is E2, the estimated error rate E at time T can be expressed by the following equation. The equation of the straight line passing through the two points is E = ((E2-E1) / (T2-T1)) T + (E1T2-E2T1). If the combinations of (T1, E1) and (T2, E2) are estimated one after another, the combinations of (T, E) can also be calculated one after another. The actual value of T2-T1 is suitably about 0.5 to 5 seconds.

  Since data transmission by packet is discontinuous, it is difficult for the transmitting side (base station) to quickly grasp the mobile environment / radio wave environment where the receiving side (mobile station) is located. By providing the base station 21 with the change rate calculation means 208, the base station 21 becomes more effective.

  FIG. 45 is a flowchart showing the flow of processing. According to the flowchart of FIG. 45, after the transmission data number counting step S123, the presence / absence of the number of retransmission data is determined at step S124, the number of retransmission data is counted at step S125, and the error rate is calculated at step S126. In step S127, the error rate is sampled, and in step S128, the error rate change rate is calculated. By calculating the rate of change of the error rate, it is possible to estimate a change in the radio wave environment on the receiving side, and it is possible to quickly perform retransmission control and improve throughput.

  The mobile terminal of the present invention includes a mobile phone using mobile communication, a personal digital assistant (PDA) having a mobile communication function, a mobile terminal, a car navigation device, and the like.

  The present invention is mainly aimed at improving the system throughput in a mobile radio communication system, but can also be applied to a satellite mobile radio communication system, a mobile optical communication system, and the like.

In the best mode for carrying out the present invention, it is a system configuration diagram of a base station and a mobile station. In the best mode for carrying out the present invention, it is a chart for reporting a retransmission interval from a base station to a plurality of mobile stations using a notification channel. In the best mode for carrying out the present invention, a retransmission control apparatus provided in a base station. In the best mode for carrying out the present invention, the receiving side receives data at the notified retransmission interval. It is the best form which implements this invention, and is a chart which transmits data by the retransmission interval notified from the transmission side. 5 is a chart showing a method for determining a retransmission interval in the best mode for carrying out the present invention. 3 is a chart showing a notification channel releasing method according to the first embodiment of the present invention. It is a chart which shows the transmission rate change method in 1st Example of this invention. It is a chart which shows the modulation system change method in 1st Example of this invention. It is a chart which shows the method of changing and transmitting the frequency channel in 1st Example of this invention. It is a chart which shows the electric power control method in 1st Example of this invention. It is a chart of the retransmission interval according to the data request rate in 2nd Example of this invention. It is a chart which shows the change method of the NAK signal transmission timing in 2nd Example of this invention. It is a chart which shows the frequency channel, data rate, and transmission power change method in 3rd Example of this invention. It is a figure which shows the structure of the frequency channel common to the best form and each implementation item. It is a figure which shows the structure of the notification channel common to the best form and each implementation item. It is a figure which shows the structure of the data channel common to the best form and each implementation item. It is the figure of the mobile station which carried out location registration or the hand-over in the service area in 3rd Example of this invention. It is a figure of the mobile station when the error rate exceeds a predetermined level in the service area in the third embodiment of the present invention. It is a figure in the 3rd Example of this invention that a BUSY state is complete | finished within a service area, and a mobile station performs resending operation | movement. It is a figure in a 3rd Example of this invention that a mobile station notifies an error rate to a base station, and a mobile station receives the data according to an error rate. It is a figure which shows the traffic and retransmission interval in the best embodiment of this invention. It is a figure which shows the error rate and retransmission interval in the best embodiment of this invention. It is a figure which shows the data rate and retransmission interval in 1st Example of this invention. The functional block diagram of the error rate estimation apparatus using the base station and the number of data in 5th Example of this invention. It is a flowchart of the estimation error rate calculation using the number of data in 5th Example of this invention. The functional block diagram of the error rate estimation apparatus using the base station and frame number in 6th Example of this invention. It is a flowchart of the estimation error rate calculation using the frame number in 6th Example of this invention. The functional block diagram of the error rate estimation apparatus using the base station and packet number in 7th Example of this invention. It is a flowchart of the estimation error rate calculation using the packet number in 7th Example of this invention. It is a data transition diagram for demonstrating 5th Example of this invention. It is a frame transition diagram for demonstrating 6th Example of this invention. It is a packet transition diagram for demonstrating 7th Example of this invention. It is a figure regarding BER for demonstrating 5th Example of this invention. It is a figure regarding FER for demonstrating 6th Example of this invention. It is a figure regarding PER for demonstrating 7th Example of this invention. It is a data transition diagram for demonstrating the 8th Example of this invention. It is a figure regarding BER for explaining the 8th example of the present invention. It is a frame transition diagram for demonstrating 9th Example of this invention. It is a figure regarding FER for demonstrating the 9th Example of this invention. It is a packet transition diagram for demonstrating 10th Example of this invention. It is a figure regarding PER for demonstrating 10th Example of this invention. It is explanatory drawing of the parity check common to the whole of this invention. It is a figure of the base station which comprised the error rate change rate calculating means of 11th Example of this invention. It is a flowchart of the base station which comprised the error rate change rate calculating means of 11th Example of this invention. It is explanatory drawing of the data structure common to the whole of this invention. It is explanatory drawing of the frame structure common to the whole of this invention. It is a detailed explanatory view of a packet structure common to all of the present invention. It is a figure which shows the chart by the side of a data transmission in a prior art. It is a figure which shows the chart by the side of a data reception in a prior art. It is a block diagram on the data receiving side in the prior art. It is a block diagram by the side of a data transmission in a prior art. It is a figure of the correspondence table which the data storage part 117 of the transmission side of a prior art memorize | stores. It is a figure of the correspondence table which the data storage part 126 of the receiving side of a prior art memorize | stores.

Explanation of symbols

1: Base station (transmitting side)
2: Mobile station (receiving side)
3: Mobile station A
4: Mobile station B
5: base station data transmission device 6: base station retransmission control device 7: base station data reception device 8: mobile station data reception device 9: mobile station data retransmission control device 10: mobile station data transmission device 87 : Notification channel 131: base station 132: mobile station 136: second mobile station 133: first sector 134: second sector 135: third sector 136: second mobile station 137: obstacle 142: transmission Buffer 143: Mobile station manager 144: Traffic manager 145: Retransmission interval manager 146: Error rate manager 147: Data rate manager 21: Transmission side (base station)
22: Transmission data 23: Transmission buffer 24: Transmitter 201: Retransmission data number counting means 202: Transmission data number counting means 203: Error rate calculation means 28: Transmission control means 29: Antenna 20: Error rate estimation means 204: Transmission data Number counting means 205: Retransmission data number counting means 206: Retransmission packet number counting means 207: Transmission packet number counting means 208: Change rate calculating means 209: Sampling means 30, 34: Address part 31, 35: Control part 32, 36: Information part 33, 37, 43, 45: FCS (frame check sequence)
44: Information section

Claims (11)

In a data retransmission control method in which an error in transmission data is detected on the reception side and retransmission is requested from the reception side to the transmission side, the retransmission interval is notified from the transmission side to the reception side in advance using a notification channel for retransmission control. When an error occurs on the reception side, the transmission side retransmits the transmission data after the notified retransmission interval in response to reception of the NAK signal from the reception side,
If the estimate of the error rate at the receiving side of the predetermined level or less at the transmitting side, the retransmission interval without notifying using a notification channel for the retransmission control to open the notification channel for the retransmission control, in advance A retransmission interval according to a predetermined condition is used. When the estimated value of the error rate reaches a predetermined level or more, a retransmission interval corresponding to traffic is notified using the notification channel for retransmission control. A characteristic data retransmission control method.   The estimated value of the error rate is divided every time a predetermined number of transmission data is transmitted, with the predetermined number of data transmitted as a denominator and the number of retransmission data retransmitted based on a request method from the receiving side as a numerator. The data retransmission control method according to claim 1, wherein the calculation result is an estimated error rate on the receiving side.   2. The data retransmission control method according to claim 1, wherein a request method from the receiving side operates in a Stop and Wait ARQ method or a Selective Repeat ARQ method.   2. The data retransmission control method according to claim 1, further comprising transmission data number counting means, retransmission data number counting means, and error rate calculation means.   2. The data retransmission control method according to claim 1, further comprising: a transmission frame number counting unit, a retransmission frame number counting unit, and an error rate calculation unit.   2. The data retransmission control method according to claim 1, further comprising: a transmission packet number counting unit, a retransmission packet number counting unit, and an error rate calculation unit.   2. The data retransmission control method according to claim 1, further comprising an error rate sampling unit and an error rate change rate calculation unit.   The data retransmission control method according to claim 1, wherein the retransmission interval is a slot interval or a time interval.   A different retransmission interval is defined in advance according to a data rate of transmission data, and when a data error occurs, retransmission data is transmitted after the retransmission interval according to the transmission data rate at that time. 2. The data retransmission control method according to 1. A retransmission control system comprising a base station and at least one mobile station and notifying a retransmission interval using a notification channel for retransmission control, wherein a data retransmission interval is set based on traffic in the service area of the base station. Calculating and notifying the data retransmission interval in advance to a second mobile station newly registered or handed over within the service area,
When the estimated error rate at the mobile station reaches a predetermined level or less, the retransmission control notification channel is released, and a retransmission interval according to a predetermined condition is used, and the estimated error rate is A data retransmission control system, wherein when a predetermined level or more is reached, a retransmission interval corresponding to traffic is notified using the notification channel for retransmission control. In a retransmission control apparatus provided in a base station for performing retransmission control of data, a data retransmission interval is calculated based on traffic in the service area of the base station, and a location registration or handover is newly performed in the service area Informing the station in advance of the data retransmission interval,
When the estimated value of the error rate at the mobile station in the service area reaches a predetermined level or less, the retransmission interval according to a predetermined condition is used without notifying the data retransmission interval, and the error rate estimation The data retransmission control device, wherein when the value reaches a predetermined level or more, the data retransmission interval is notified.

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