JP2008124613A - Radio communication system, mobile terminal device, and base station device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication system, a mobile terminal device, and a base station device that can reduce packet loss by increasing correcting capability according to the state of a transmission band and the change state of a communication band of the radio communication system. <P>SOLUTION: In a transmission signal processing unit 8, a controller 16 normally gives commands to connect switches 14 and 15 to sides A, but gives commands to connect the switches 14 and 15 to sides B based upon information on a phenomenon of transmission packet loss, such as blocking information, information on reception signal deterioration, and band change information. Once the switches 14 and 15 are connected to the sides B, loss correction encoding processing for a transmission packet is performed. An identification code adding circuit 18 adds an identification code indicating that the loss correction encoding processing has been performed to the transmission packet after the loss correction encoding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention reduces the loss of packets being transmitted and received when there is a momentary interruption of the wireless communication line that occurs when the transmission path is degraded, such as blocking, shadowing, fading, or when the transmission speed is switched. The present invention relates to a wireless communication system, a mobile terminal apparatus, and a base station apparatus that perform wireless communication.

  In wireless communication, when blocking, shadowing, fading, etc. occur in the wireless transmission path and the transmission path is degraded, or when changing the transmission band to match the traffic volume, An instantaneous interruption may occur, and a packet transmitted on the wireless communication line may be lost due to the instantaneous interruption. This packet loss occurs in a transmission path between the mobile terminal device and the base station device in the terrestrial wireless communication system, and between the mobile terminal device and the communication satellite or between the communication satellite and the base station device in the satellite communication system. Occurs in each transmission line between. However, since the transmission path between the base station apparatus and the communication satellite in the satellite communication system is one in which the base station apparatus is arranged at a position where the communication satellite has a good line of sight, it is difficult to be shielded by a building, There may be a momentary disconnection of the wireless communication line due to the deterioration of the transmission path due to the weather conditions or due to the change of the transmission band. For example, Japanese Patent Laid-Open No. Hei 8-298688 discloses a method for reducing packet loss in a mobile terminal apparatus that can communicate with a base station using both a communication satellite line and a terrestrial radio line. . According to this publication, a mobile terminal device uses a block code that prioritizes error correction capability when a terrestrial radio channel is selected, and a block that prioritizes erasure correction capability when a satellite communication channel is selected. The code is used.

JP-A-8-298688

  The method described in Patent Document 1 uses both an erasure correction code and an error correction code in wireless communication using a terrestrial communication line and a satellite communication line, and gives priority to their correction capability to the terrestrial wireless system. However, in this system, both the erasure correction code and the error correction code are always performed, so that the number of parity packets generated by these encoding increases, and the information packet to be transmitted is transmitted. There was a problem that the transmission speed was lowered.

  The present invention has been made to solve the above-described problems, and can improve the correction capability and reduce packet loss in accordance with the state of the transmission path and the change of the communication band in the wireless communication system. An object of the present invention is to obtain a wireless communication system, a mobile terminal device, and a base station device.

  The radio communication system according to the invention of claim 1 is a radio communication system that performs radio communication between a mobile terminal apparatus and a base station apparatus, wherein the mobile terminal apparatus adds an error detection code to a packet. Erasure correction encoding means for performing erasure correction encoding on the packet, identification code adding means for adding an identification code to the packet that has been erasure correction encoded by the erasure correction encoding means, and information on events that cause transmission packet loss Switching means for switching from a state in which a transmission packet is input to the error detection adding means to a state in which the transmission packet is input to the error detection adding means via the erasure correction encoding means and the identification code adding means. The base station apparatus includes an error detection means for detecting an error in a received packet transmitted from the mobile terminal apparatus, and the identification code. Received packet are assigned is obtained by and a erasure correction decoding means for erasure correction decoding of.

  According to a second aspect of the present invention, there is provided a mobile terminal apparatus comprising: an error detection adding unit that adds an error detection code to a packet; an erasure correction encoding unit that performs erasure correction encoding on the packet; and an erasure correction code using the erasure correction encoding unit. Identification code adding means for adding an identification code to the converted packet, and based on information on an event that causes transmission packet loss, the erasure correction coding means, Switching means for switching to a state of inputting to the error detection adding means via the identification code adding means.

  According to a third aspect of the present invention, there is provided a base station apparatus comprising: an error detection means for detecting an error of a received packet transmitted from a mobile terminal apparatus; and a received packet that has been erasure corrected by an identification code included in the received packet. Packet identifying means for identifying, and erasure correction decoding means for erasure correcting decoding the received packet that has been subjected to erasure correction coding identified by the packet identifying means.

  A base station apparatus according to a fourth aspect of the present invention is the base station apparatus according to the third aspect of the present invention, further comprising: a transmission unit that transmits a transmission packet to the mobile terminal apparatus; and an error detection code added to the transmission packet. Error detection addition means, erasure correction coding means for erasure correction coding the transmission packet, identification code addition means for adding an identification code to the transmission packet erasure correction coded by the erasure correction coding means, Based on the information of the event that causes the transmission packet loss, the error detection adding means passes from the state where the transmission packet is input to the error detection adding means to the error detection adding means via the erasure correction coding means and the identification code adding means. Switching means for switching to an input state.

  A base station apparatus according to a fifth aspect of the present invention is the base station apparatus according to the fourth aspect of the present invention, wherein the information of the event that causes the transmission packet loss is identified by the received packet that has been subjected to the erasure correction coding by the packet identification means. That is what has been done.

  According to the first to fifth aspects of the present invention, the erasure correction coding means and the identification code are added from the state in which the transmission packet is input to the error detection / addition means based on the information of the event that causes the transmission packet loss. By switching to the state of inputting to the error detection / addition means via the means, the correction capability can be increased and the packet loss can be reduced in accordance with the state of the transmission path and the change state of the communication band.

Embodiment 1

  A radio communication system according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of a radio communication system according to Embodiment 1 of the present invention. FIG. 1A shows a case of a satellite communication system that performs communication between a mobile terminal device and a base station device via a communication satellite, and FIG. 1B shows a case of a terrestrial cellular system. In FIG. 1, 1 is a mobile terminal device, 2 is a base station device, 3 is a communication satellite, and 4 is a terminal device connected to the base station device 2. Reference numeral 5 denotes an uplink communication line from the mobile terminal apparatus 1 to the base station apparatus 2, and 6 denotes a downlink communication line from the base station apparatus 2 to the mobile terminal apparatus 1. In FIG. 1A, the mobile terminal device 1 can communicate with the base station device 2 via the communication satellite 3, and further via the base station device 2, the terminal device 4 and other mobile terminal devices 1. Both communicate with each other. On the other hand, in FIG.1 (b), the mobile terminal device 1 can communicate with the base station apparatus 2, and communicates with the other mobile terminal apparatus 1 from the base station apparatus 2 via a network. In the present invention, communication between the mobile terminal device 1 and the base station device 2 includes indirect communication via the communication satellite 3 shown in FIG. 1 (a) and direct communication shown in FIG. 1 (b). It includes both communications.

  Next, configurations of the mobile terminal apparatus 1 and the base station apparatus 2 will be described. 2 is a functional block diagram showing the configuration of mobile terminal apparatus 1 according to Embodiment 1 of the present invention, and FIG. 3 is a functional block diagram showing the configuration of base station apparatus 2 according to Embodiment 1 of the present invention. is there. In FIG. 2, 7 is an input terminal for inputting a transmission packet transmitted by the mobile terminal apparatus 1, and the transmission packet is a packet in which video, audio, data and the like are stored. A transmission signal processing unit 8 performs error detection processing and erasure correction processing by switching. Reference numeral 9 denotes a transmission unit, 10 denotes an antenna that performs communication with the base station apparatus 2, 11 denotes a reception unit, and 12 denotes a reception signal processing unit. Reference numeral 13 denotes an output terminal for outputting the received packet. In the transmission signal processing unit 8, 14 and 15 are switches that operate as a pair, and switch whether to perform erasure correction processing on the transmission packet or to bypass the processing. A control unit 16 controls the switch. Reference numeral 17 denotes an erasure correction encoding circuit that performs erasure correction encoding on the transmission packet. Reference numeral 18 denotes an identification code addition that adds an identification code indicating that the erasure correction encoding processing is performed on the transmission packet that has been subjected to the erasure correction encoding processing. Circuit. An error detection addition circuit 19 adds an error detection code. Reference numeral 20 denotes an error detection circuit for detecting an error in the received packet. Reference numeral 21 denotes a packet identification circuit for identifying whether or not erasure correction coding processing has been performed on the received packet detected to have been normally received by this error detection. It is. Reference numeral 22 denotes an erasure correction decoding circuit that performs erasure correction decoding of a received packet that has been identified by the packet identification circuit 21 as being subjected to erasure code correction processing. Reference numeral 23 denotes a packet multiplexer that multiplexes the received packet identified as not being subjected to the erasure correction coding process by the packet identification circuit 21 and the received packet decoded by the erasure correction decoding circuit 22.

  In the transmission unit 9, 24 is an error correction encoder that performs error correction encoding on the transmission packet from the transmission signal processing unit 8, 25 is a modulator that modulates the transmission signal after error correction encoding, and 26 Is a high-frequency converter that performs high-frequency conversion on the modulated transmission signal, and 27 is a high-output amplifier that amplifies the transmission signal after high-frequency conversion and outputs it to the antenna 10. In the receiving unit 11, 28 is a low noise amplifier that amplifies the received signal received by the antenna with low noise, 29 is a low frequency converter that converts the received signal after low noise amplification to low frequency, and 30 is a received signal after low frequency conversion. The demodulator 31 demodulates the received signal and performs error correction on the received signal and outputs it to the received signal processing unit 12.

  Next, the configuration of the base station apparatus 2 will be described. In FIG. 3, 32 is a transmission packet input terminal, 33 is a plurality of transmission signal processing units corresponding to a plurality of communication channels handled by the base station apparatus 2, 34 is a transmission unit corresponding to each transmission signal processing unit 33, 35 is A synthesizer 36 that synthesizes transmission signals of a plurality of channels, 36 is a high-power amplifier that amplifies the high-frequency transmission signal after synthesis, and 37 is an antenna that communicates with the mobile terminal device 1. 38 is a low noise amplifier for amplifying the received signal with low noise, 39 is a distributor for distributing the received signal to a plurality of communication channels, 40 is a receiving unit corresponding to each communication channel, and 41 is a received signal processing corresponding to each communication channel. Part. In addition, in the circuit block in the base station apparatus 2 of FIG. 3, the same name is attached | subjected to the block equivalent to the circuit block in the mobile terminal apparatus 1 of FIG. 2, and the circuit block in the mobile terminal apparatus 1 of FIG. It has a corresponding function.

  Next, operations of the mobile terminal device 1 and the base station device 2 will be described. In a state where the transmission path is not deteriorated or the communication band is not changed, the mobile terminal apparatus 1 bypasses the erasure correction coding by connecting the switches 14 and 15 to the A side in FIG. On the other hand, when it is detected that the transmission path is deteriorated or the communication band is changed, the switches 14 and 15 are in the period shown in FIG. It is connected to the B side and performs erasure correction coding processing on the transmission packet. As a state in which the mobile terminal device 2 detects the deterioration of the transmission path, the channel quality of the received signal received by the mobile terminal apparatus 1 through the downlink communication line 6 is deteriorated, and the similar transmission path deterioration is caused in the uplink communication line 5. May also occur. The channel quality of the received signal can be detected by the bit error rate (BER), the reception level, etc. in the demodulator 30. In addition, a place where the outlook of the communication satellite 3 or the base station apparatus 2 is bad is mapped as a specific area such as a surrounding area of a high-rise building in an urban area or a mountain area, and the position of the mobile terminal device 1 is the specific area on the map. Is determined from the map coordinate position and is input to the terminal as an information signal such as blocking. The position of the mobile terminal device 1 can be measured by a GPS receiver. In FIG. 2, a GPS receiver, map data, and a determination circuit based on coordinate positions are not shown.

  Furthermore, the transmission path may be momentarily interrupted when the communication band is changed. The change of the communication band is intended to effectively use the frequency by increasing or decreasing the bandwidth when the amount of transmission information transmitted by the mobile terminal apparatus 1 increases or decreases. An information amount measurement circuit for measuring the amount of transmission information is provided to determine whether or not a band change is necessary. This information amount measurement circuit measures the amount of transmission information by monitoring, for example, the window size added to the TCP / IP packet and the increase / decrease in the amount of data actually buffered in the mobile terminal device. Such increase / decrease in the amount of transmission information may occur in response to an application request, or may occur when a plurality of information terminals or telephone devices are connected to the mobile terminal device 1. When it is necessary to change the band, the mobile terminal apparatus 1 superimposes the band change request signal on the transmission signal and transmits it to the base station apparatus 2. This band change request signal may be a signal in which a specific necessary transmission amount is stored in a packet, or may be a signal simply requesting an increase or decrease in the band. The base station apparatus 2 reads the band change request signal from the transmission signal from the mobile terminal apparatus 1 and allocates a new communication band to the mobile terminal apparatus 1 if the requested bandwidth can be increased. When a signal that simply requests increase or decrease in bandwidth is used, the base station apparatus 2 performs line change assignment so that the bandwidth is increased or decreased by a step width set in advance in the communication system. The base station apparatus 2 transmits a band allocation signal including a new communication band (center frequency and bandwidth) to the mobile terminal apparatus 1 that has requested the band change, and the mobile terminal apparatus 1 determines a communication band based on the band allocation signal. To change. The change of the communication band is performed by the modulator 25 and the high frequency converter 26 in the transmission unit 9 of the mobile terminal device 1.

  Information on events that cause loss of these transmission / reception packets (that is, information such as blocking, BER information, reception level information, band change information, etc.) is input to the control unit 16, and the control unit 16 performs erasure correction encoding processing. A period (start and end) to be performed is set, and erasure correction coding processing is performed on the transmission packet. Specifically, the control unit 16 determines a period during which degradation or blocking of a received signal occurs or a predetermined period including a band change point based on input information such as blocking, BER information, reception level information, and band change information. In this period, the switch 14 and 15 are instructed to be connected to the B side in order to perform erasure correction encoding of the transmission packet. For example, for information such as blocking, reception level information, and BER information, the deterioration is determined by comparison with a predetermined threshold value. While it is determined that the transmission packet is deteriorated, the transmission packet is transmitted within the transmission path or circuit. Erasure correction coding is performed for a period in which there is a possibility of erasure. Further, the time of band change is known, and erasure correction coding is performed for a predetermined period including at the time of the band change (at least a period corresponding to the number of packets used for erasure correction coding processing).

  The erasure correction encoding circuit 17 performs erasure correction encoding on the input transmission packet. Packet loss correction will be described with reference to FIG. In the erasure correction of FIG. 4A, the transmission side generates parity packets (P6 to P9) based on the encoding rule from the information packets (P1 to P5), and transmits these packets (P1 to P9). For some reason, the receiving side loses and receives the P2, P5, and P7 packets, but reproduces the P2, P5, and P7 packets from the correctly received packets. Further, in the erasure correction of FIG. 4B, on the transmission side, encoded packets (P6 to P14) are generated from the information packets (P1 to P5) based on the encoding rule, and the encoded packets (P6 to P14) are generated. Send. For some reason, the receiving side loses and receives the packets P7, P10, and P12, but reproduces the information packets (P1 to P5) from the correctly received packets. Various research and development are currently underway for coding rules. For example, rules using Reed-Solomon (RS) codes and LDPC (Low Density Parity Check) codes are known.

  The identification code adding circuit 18 adds an identification code indicating that the erasure correction coding process is performed to the transmission packet subjected to the erasure correction coding process, and further adds an error detection code by the error detection adding circuit 19. While the erasure correction encoding by the erasure correction encoding circuit 17 encodes a plurality of transmission packets as one packet block, the error detection addition by the error detection addition circuit 19 is performed for each transmission packet. This is a process of adding a parity bit for error detection. In this error detection addition, a parity bit for error detection is generated by, for example, a CRC (Cyclic Redundancy Check) cyclic code or the like and added to the packet. The error correction encoder 24 performs an error correction encoding process on the transmission packet after the error detection is added. This error correction encoding process is an error correction encoding process using, for example, a convolutional code or a turbo code. The error correction encoded transmission packet is modulated by the modulator 25, converted to high frequency by the high frequency converter 26, amplified by the high output amplifier 27, and transmitted from the antenna 10. This transmission signal is received by the base station apparatus 2.

  Next, the operation of the receiving side circuit of the mobile terminal apparatus 1 will be described. The transmission signal transmitted from the base station apparatus 2 is received by the antenna 10, the received signal is subjected to low noise amplification and low frequency conversion, and demodulated by the demodulator 30. The error correction circuit 31 performs error correction by performing Viterbi decoding processing and turbo decoding processing on the received packet after demodulation. The error detection circuit 20 performs a parity check of each received packet and determines whether or not the packet is correctly received. The error detection circuit 20 discards a received packet in which a parity error has occurred. For example, packets that are not correctly received, such as P2, P5, and P7 in FIG. 4A, are lost due to a parity error generated by the error detection circuit 20, and are discarded. The received packet determined to have been correctly received in the error detection process is input to the packet identification circuit 21 and is identified by the identification code whether or not erasure correction coding has been performed. Note that whether or not to perform erasure correction coding processing on a transmission signal from the base station apparatus 2 to the mobile terminal apparatus 1 is similar to that of the mobile terminal apparatus 1, but this will be described later. Even when the erasure correction coding process is performed on the transmission signal from the base station apparatus 2 to the mobile terminal apparatus 1, the identification code is attached in the same manner as the identification code adding circuit 18 in the mobile terminal apparatus 1. A received packet identified as being erasure correction encoded by this identification code is input to the erasure correction decoding circuit 22, and a received packet identified as not being erasure corrected encoded is input to the packet multiplexer 23. Is done. The erasure correction decoding circuit 22 performs packet reproduction processing based on the decoding rule, and outputs the reproduced received packet to the packet multiplexer 23. The packet multiplexer 23 multiplexes the input received packet and outputs it.

  Next, the operation of the base station apparatus 2 will be described. In the circuit on the transmission side of the base station device 2, the operation of the transmission signal processing unit 33 constituting each communication channel is the same as that of the transmission signal processing unit 8 of the mobile terminal device 1, but the control unit 45 uses the switch 43 and the switch The control for switching 44 may be different. That is, in the satellite communication system, since the base station apparatus 2 is fixedly installed in a place where the communication satellite 3 has a good line of sight, transmission line deterioration due to blocking caused by movement like the mobile terminal apparatus 1 is not a problem. Don't be. Also in the case of a terrestrial communication system, the base station device 2 determines whether or not the mobile terminal device 1 is located in an area where procking occurs based on position information of the plurality of mobile terminal devices 1. Is too complicated to be feasible. On the other hand, depending on the weather conditions, the transmission path of the transmission line (downlink communication line 6) from the base station apparatus 2 to the mobile terminal apparatus 1 may deteriorate, and the mobile terminal apparatus 1 requires a band change, When the transmission line (downlink communication line 6) of the base station apparatus 2 is switched after assigning a new communication band, an instantaneous interruption may occur during the switching. In these cases, there is a possibility that packet loss may occur in transmission from the base station apparatus 2 to the mobile terminal apparatus 1, and the control unit 45 of the base station apparatus 2 performs the erasure correction coding process on the transmission packet with the switch 43. It operates to connect the switch 44 to the B side. Also, the received signal from the mobile terminal apparatus 2 is processed by the received signal processing unit 41, and the packet identification circuit 56 in the received signal processing unit 41 is subjected to erasure correction coding processing on the received packet. When the identification code is detected, it can be seen that the mobile terminal apparatus 1 side determines that there is a cause of packet loss on the transmission path, so that the base station apparatus 2 determines that the identification code in the received packet is detected. The control unit 45 may instruct the switches 43 and 44 to connect to the B side so that the transmitted packet is processed via the erasure correction coding circuit 46. In the receiving side circuit of the base station apparatus 2, the transmission signal transmitted from the mobile terminal apparatus 1 is received by the antenna 37, the received signal is amplified with low noise, distributed to each communication channel by the distributor 39, and subjected to low frequency conversion. Demodulate. The signal processing in the error correction circuit 54 for processing the received packet after demodulation and each received signal processing unit 41 is the same as the operation of the receiving side circuit of the mobile terminal device 1, and the description is omitted.

  In the base station apparatus 2, when the packet identification circuit 56 detects an identification code that the erasure correction coding processing is performed on the received packet, the control unit 45 instructs the switch 43 and 44 to connect to the B side. In the above description, a case where the transmission packet from the base station apparatus 2 is subjected to the erasure correction encoding process via the erasure correction encoding circuit 46 is described. Similarly, in the mobile terminal apparatus 1, the packet identification circuit 21 receives the received packet. When the identification code indicating that the erasure correction coding process is performed is detected, the controller 16 instructs the switches 14 and 15 to connect to the B side, and the transmission packet from the mobile terminal apparatus 1 is lost. It is also possible to perform erasure correction encoding processing via the correction encoding circuit 17. When such a process is performed, it becomes a problem which of the mobile terminal apparatus 1 and the base station apparatus 2 is more actively performing the erasure correction coding process. However, the following control is possible. it can.

  Now, the base station apparatus 2 detects the identification code indicating that the received packet has been subjected to the erasure correction encoding process by the packet identification circuit 56, and the communication terminal apparatus 1 A state in which a transmission packet is subjected to erasure correction encoding based on detection of an identification code indicating that the received packet has been subjected to erasure correction encoding processing by the packet identification circuit 21 is set as a subordinate state. On the other hand, in communication terminal apparatus 1 and base station apparatus 2, erasure correction coding processing is performed on transmission packets based on information on events that cause loss of transmission packets based on information such as blocking, BER information, reception level information, and band change information. Let the state in which it is performing an independent state. In the identification code adding circuit 18 in the communication terminal apparatus 1 and the identification code adding circuit 47 in the base station apparatus 2, a state code (referred to as a subordinate code or an independent code) for identifying the above-described dependent state or independent state in a transmission packet, For example, 1 or 0 bit information) is added.

  For example, an event in which transmission packet loss occurs in the mobile terminal device 1 from a state in which neither the mobile terminal device 1 nor the base station device 2 performs erasure correction coding processing on the transmission packet (hereinafter referred to as a normal state). When the state is changed to the state in which the erasure correction encoding process is performed on the transmission packet based on the information, that is, the state shifts to the independent state, the base station apparatus 2 enters the subordinate state and performs the erasure correction encoding process on the transmission packet. At this time, an independent code is attached to the transmission packet from the mobile terminal apparatus 1, and a dependent code is attached to the transmission packet from the base station apparatus 2. From this state, when the base station device 2 shifts to the independent state, the transmission packet from the base station device 2 is also given an independent code. From this state, when there is no event that the transmission packet disappears in any one device, for example, the mobile terminal device 1, the received packet received by the mobile terminal device 1 has an independent code. The transmission of 1 shifts from the independent state to the dependent state, and the transmission packet is given a dependent code. From this state, if there is no event in the base station apparatus 2 that causes the loss of the transmission packet, the received packet received by the base station apparatus 2 has a subordinate code, so that the transmission of the base station apparatus 2 is in an independent state. , The transmission packet transmitted from the base station apparatus 2 is not subjected to the erasure correction coding process, and the mobile terminal apparatus 1 that has received the packet shifts from the subordinate state to the normal state, and the mobile terminal apparatus 1 transmits the transmission packet. The transmission packet is also not subjected to the erasure correction coding process.

  As described above, the mobile terminal apparatus 1 is more susceptible to transmission path blocking, shadowing, fading, and the like than the base station apparatus 2, and the period during which the transmission path is deteriorated or when the communication band is changed. During the period including the erasure, the transmission packet from the mobile terminal apparatus 1 is subjected to erasure correction coding, and the base station apparatus 2 reproduces the packet that is received and lost by erasure correction decoding, thereby improving the correction capability and reducing the packet loss. be able to. Similarly, on the base station device 2 side, means for performing erasure correction coding processing on the transmission packet is provided, and the erasure correction coding processing is switched based on information on an event that causes packet loss, so that the base station device 2 As for transmission packets from, the correction capability can be increased and packet loss can be reduced. Also, by switching the presence / absence of erasure correction encoding processing based on information on events that cause packet loss such as information such as fading, BER information, reception level information, and band change information, parity packets generated by encoding The increase can be suppressed, and the deterioration of the transmission speed and efficiency of the information packet to be transmitted can be suppressed.

It is a block diagram showing the structure of the radio | wireless communications system which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the mobile terminal device 1 which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the base station apparatus 2 which concerns on Embodiment 1 of this invention. It is a schematic diagram explaining the packet loss correction method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile terminal apparatus 2 Base station apparatus 14, 15 switch 16 Control part 17 Erasure correction encoding circuit 18 Identification code addition circuit 19 Error detection addition circuit 20 Error detection circuit 21 Packet identification circuit 22 Erasure correction decoding circuit

Claims (5)

In a wireless communication system that performs wireless communication between a mobile terminal device and a base station device, the mobile terminal device includes an error detection adding unit that adds an error detection code to a packet, and an erasure correction code that performs erasure correction coding on the packet. Based on the information of the event that causes the transmission packet loss based on the information of the event that causes the transmission packet loss, the identification code adding means for adding the identification code to the packet that has been erasure correction encoded by the erasure correction encoding means Switching means for switching from an input state to a state of inputting to the error detection adding means via the erasure correction encoding means and the identification code adding means, and the base station apparatus includes the mobile terminal Error detection means for detecting an error in a received packet transmitted from the apparatus, and erasure correction decoding of the received packet with the above identification code Wireless communication system, characterized by comprising a erasure correction decoding section that. Error detection adding means for adding an error detection code to a packet, erasure correction encoding means for erasing correction encoding a packet, and an identification code for adding an identification code to a packet erasure correction encoded by the erasure correction encoding means Based on the information on the event that causes transmission packet loss, the error detection is performed via the erasure correction coding unit and the identification code addition unit from the state where the transmission packet is input to the error detection addition unit. A mobile terminal apparatus comprising switching means for switching to a state of input to the adding means. An error detection means for detecting an error of a received packet transmitted from a mobile terminal device, a packet identification means for identifying a received packet that has been erasure-corrected by an identification code included in the received packet, and a packet identification means A base station apparatus comprising: a erasure correction decoding unit configured to perform erasure correction decoding on an identified received packet subjected to erasure correction coding. 4. The base station apparatus according to claim 3, further comprising: a transmission unit that transmits a transmission packet to the mobile terminal apparatus; an error detection addition unit that adds an error detection code to the transmission packet; and an erasure correction code for the transmission packet. Erasure correction coding means to be converted, identification code adding means for adding an identification code to the transmission packet that has been erasure correction coded by the erasure correction coding means, and the transmission based on the information of the event that causes the transmission packet loss Switching means for switching from a state where the packet is input to the error detection adding means to a state where the packet is input to the error detection adding means via the erasure correction coding means and the identification code adding means. A characteristic base station apparatus. 5. The base station apparatus according to claim 4, wherein the information on the event that causes the transmission packet loss is that the received packet that has been subjected to the loss correction coding is identified by the packet identification unit.

Images