JP2006013843A - System, apparatus, and method for radio communication, and computer program - Google Patents

System, apparatus, and method for radio communication, and computer program Download PDF

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JP2006013843A
JP2006013843A JP2004187407A JP2004187407A JP2006013843A JP 2006013843 A JP2006013843 A JP 2006013843A JP 2004187407 A JP2004187407 A JP 2004187407A JP 2004187407 A JP2004187407 A JP 2004187407A JP 2006013843 A JP2006013843 A JP 2006013843A
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transmission
wireless communication
frame
reflected wave
retransmission
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Hirotaka Muramatsu
Takayuki Ogiso
貴之 小木曽
広隆 村松
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Sony Corp
ソニー株式会社
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Abstract

<P>PROBLEM TO BE SOLVED: To appropriately transmit data by a time division multiplex system in an asymmetrical transmission line where a transmission speed differs by each direction between reflectors or reflected wave readers. <P>SOLUTION: A TDD system with a frame length fixed therein is adopted during data communication. A frame constitution by which a plurality of frames are connected and transmitted as a packet including one transmission burst is used in an up-link for mainly performing data transmission. In the case of a plurality of re-transmission frames, the frames are closed so as to be distributed in order without continuously re-transmitting the same frame. Accordingly, throughput is improved in the case of the occurrence of an error in terms of the burst which easily occurs in the transmission line. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless communication system, a wireless communication apparatus, a wireless communication method, and a computer program that realize a communication operation with low power consumption between devices at relatively short distances. Back-scatter wireless communication system, wireless communication apparatus, wireless communication method, and computer for performing data communication using modulation carrier transmission and reflected wave modulation based on antenna load impedance switching operation on reflector side, etc.・ Regarding the program.

  More specifically, the present invention relates to a wireless communication system that performs data transmission by a time division multiplex (TDD) method on an asymmetric transmission line having different transmission speeds in each direction between reflectors or reflected wave readers. TECHNICAL FIELD The present invention relates to a communication apparatus, a wireless communication method, and a computer program. In particular, a high-speed uplink from a reflector to a reflected wave reader is used in an asymmetric transmission line having different transmission speeds between reflectors or reflected wave readers. The present invention relates to a wireless communication system, a wireless communication apparatus, a wireless communication method, and a computer program that efficiently transmit data.

  By connecting a plurality of devices to the network, it is possible to achieve efficient command and data transmission, sharing information resources, and sharing hardware resources. More recently, wireless networks have attracted attention as systems that release users from wired wiring.

  Examples of standard specifications relating to wireless networks include IEEE (The Institute of Electrical and Engineering Engineers) 802.11, HiperLAN / 2, IEEE 802.15.3, Bluetooth communication, and the like. In recent years, wireless LAN systems have become popular, coupled with the fact that wireless LAN systems have become cheaper and have been built into PCs as standard.

  A relatively small wireless communication system is used for data transmission between a host device and a terminal device in a home or the like. Examples of the host device mentioned here include stationary home appliances such as a television, a monitor, a printer, a PC, a VTR, and a DVD player. Examples of terminal devices include mobile devices such as digital cameras, video cameras, mobile phones, personal digital assistants, and portable music players that want to minimize power consumption. An application of this type of system is uploading image data taken with a mobile phone with a camera or a digital camera to a PC via a wireless LAN.

  However, the wireless LAN is originally designed and developed on the assumption that it is used in a computer, and its power consumption becomes a problem when mounted on a mobile device. Many of the IEEE802.11b wireless LAN cards currently on the market have a power consumption of 800 mW or more when transmitting and 600 mW or more when receiving. This power consumption is a heavy burden for battery-powered portable devices.

  Even if the wireless LAN function is operated in a limited range and the transmission power is reduced, the power consumption can be reduced by only about 80%. In particular, since transmission from an image input device such as a digital camera to the image display device is in a communication form in which the transmission ratio occupies the entire communication, wireless transmission means with low power consumption is still required.

  In addition, the Bluetooth communication has a low transmission speed of 720 kbps at the maximum, which is inconvenient because it takes a long time to transmit an image having a high image quality and a large file size.

  On the other hand, wireless transmission using reflected waves based on the back scatter method used in RFID realizes low power consumption in a communication mode in which the transmission ratio occupies most of the communication between devices, for example. be able to.

  A back-scatter wireless communication system includes a reflector that transmits data using a modulated reflected wave, and a reflected wave reader that reads data from the reflected wave from the reflector. During data transmission, the reflected wave reader transmits an unmodulated carrier. On the other hand, the reflector transmits data by performing a modulation process corresponding to the transmission data on the unmodulated carrier by using a load impedance operation such as on / off of the end of the antenna, for example. The reflected wave reader side can receive the reflected wave, demodulate and decode it, and acquire transmission data.

  In a reflected wave transmission system, an antenna switch for performing back scattering is generally composed of an IC of gallium arsenide, and its power consumption is several tens of μW or less. As an average power when data transmission is performed, In the case of the delivery confirmation method, data transmission is possible at 10 mW or less, and in the unidirectional transmission, data transmission is several tens of μW. This is an overwhelming performance difference compared to the average power consumption of a general wireless LAN (for example, see Non-Patent Document 1).

  FIG. 8 schematically shows a system configuration example using reflected wave transmission. For example, a reflector is incorporated in a mobile terminal device such as a digital camera, a video camera, a mobile phone, a personal digital assistant, a portable music player, etc. to minimize power consumption, and a TV, monitor, printer, PC, A reflected wave reader is incorporated in a host device such as a VTR, DVD player, or other stationary home appliances. For example, image data taken with a camera-equipped mobile phone or digital camera can be uploaded to a PC via a reflected wave transmission path, and image data can be stored, displayed, and printed out.

  The reflected wave transmission system is used, for example, to connect a reflector and a digital camera, connect a reflected wave reader and a PC, and transmit image data of the digital camera to the PC. As a transmission method (protocol) used at this time, a TDD (Time Division Duplex) method in which radio waves of the same frequency are shared by time division between upstream and downstream is used. FIG. 9 shows an operation example of the reflected wave transmission system employing the TDD method. In this system, since reflection is used, the reflected wave reader side repeats a state of transmitting a non-modulated carrier and receiving the reflected wave, and a state of transmitting data by itself using a modulated wave. On the reflector side, data is returned on the non-modulated carrier and returned as a reflected wave, and then the state of receiving the modulated wave from the reflected wave reader side is repeated.

  Here, the above-described reflected wave transmission system is an asymmetric transmission system in which the transmission rate of the uplink from the reflector to the reflected wave reader is different from that of the downlink from the reflected wave reader to the reflector. For this reason, when a retransmission control method is used in which transmission confirmation is exchanged by Ack or Nack for each frame in a single frame transmission in the TDD scheme, the downlink time ratio increases, so uplink transmission The speed will be insufficient.

  10 and 11 illustrate an example of a frame configuration in the reflected wave transmission system and an image of the time relationship between the uplink and the downlink in that case.

  FIG. 10 shows an example of a transmission frame configuration in the reflected wave transmission system. When an unmodulated carrier is transmitted from the reflected wave reader side 3-a, an uplink packet is transmitted from the reflector side 3-b as a reflected wave for the unmodulated carrier. The reflected wave reader returns a confirmation of Ack or Nack delivery in the frame 3-a in response to the reception of the information received in response to the received information.

  FIG. 11 shows an example of a TDD communication operation using this frame. The reflected wave transmission system has, for example, an asymmetric TDD transmission line with an uplink transmission rate of 10 Mbps and a downlink transmission rate of 1 Mbps. In such a case, there is a problem in that the time required for uplink in communication is short and time cannot be used for data transmission, which is the main subject, that is, the effective speed becomes extremely low with respect to the transmission speed. .

Japanese Patent Application No. 2003-291809 Specification

  An object of the present invention is to suitably perform data communication using transmission of an unmodulated carrier from the reflected wave reader side and modulation of the reflected wave based on an antenna load impedance switching operation on the reflector side. Another object of the present invention is to provide a wireless communication system, a wireless communication apparatus, a wireless communication method, and a computer program that are excellent in backscattering.

  A further object of the present invention is to provide an excellent radio communication system and radio communication apparatus capable of suitably performing data transmission by the TDD method on an asymmetric transmission path having different transmission speeds in each direction between reflectors or reflected wave readers. And a wireless communication method, and a computer program.

  A further object of the present invention is due to the effect of the slow downlink using a fast uplink from the reflector to the reflected wave reader in an asymmetric transmission line with different transmission rates between the reflectors or reflected wave readers. An object of the present invention is to provide an excellent wireless communication system, wireless communication apparatus and wireless communication method, and computer program capable of efficiently performing data transmission while suppressing a decrease in effective transmission rate.

  Another object of the present invention is to perform retransmission control with high transmission efficiency by using a frame configuration in which a plurality of frames are concatenated and transmitted as one transmission burst in an asymmetric transmission line having different transmission speeds between reflectors or reflected wave readers. It is an object to provide an excellent wireless communication system, wireless communication apparatus, wireless communication method, and computer program capable of performing the above.

  The present invention has been made in consideration of the above-mentioned problems, and is a radio that performs reflected wave transmission by transmitting an unmodulated carrier from the reflected wave reader side and modulating the reflected wave according to transmission data on the reflector side. A communication system, which employs a time division multiplexing system in which a frame length is fixed during data communication, and transmits a plurality of frames in one transmission packet in an uplink transmission burst from the reflector to the reflected wave reader. A wireless communication system characterized by being configured to be connected.

  However, “system” here refers to a logical collection of a plurality of devices (or functional modules that realize specific functions), and each device or functional module is in a single housing. It does not matter whether or not.

  The wireless transmission system according to the present invention is intended to realize low power consumption in a communication mode in which a transmission ratio occupies most of communication between devices that are relatively limited to a short distance, Wireless transmission is performed using modulation of reflected waves based on the back scatter method used in RFID. The RFID system itself is widely known in the art as an example of a wireless communication means that can be applied only at an extremely short distance.

  The reflected wave transmission system is an asymmetric transmission system in which the transmission rate of the uplink from the reflector to the reflected wave reader is different from that of the downlink from the reflected wave reader to the reflector. For this reason, in a retransmission control method in which transmission confirmation is exchanged for each frame in a single frame in TDD transmission, the downlink time ratio becomes high and the uplink transmission rate becomes insufficient. There is.

  Therefore, in the wireless communication system according to the present invention, a TDD scheme with a fixed frame length is adopted during data communication, and in the uplink mainly performing data transmission, a plurality of frames are connected to form one transmission burst. A frame configuration to be transmitted as a packet is used. By transmitting a packet by concatenating a plurality of frames, it is possible to improve the effective transmission rate (throughput) of the uplink.

  On the other hand, in the retransmission control, a stop & wait retransmission control system that performs partial retransmission in erroneous frames is adopted.

  Here, when sending the same number of erroneous frames as the fixed number of connections, if the same frame is sent several times at a time, it may cause an error again even though the frame is resent several times. ineffective. In particular, transmission path errors in a reflected wave transmission system are more susceptible to burst errors because they are dominant.

  Therefore, in the present invention, when a plurality of frames are retransmitted by the stop and wait retransmission control method, the retransmitted frames are repeatedly transmitted alternately. In other words, when there are multiple retransmitted frames, the same frame is not retransmitted continuously, but the frames are packed so that they are distributed in order. Throughput can be improved.

  In addition, when the reflector connects multiple frames in the uplink direction and transmits or retransmits one transmission burst, the reflected wave is read by placing a preamble and frame synchronization bit (unique word) in each frame. On the receiver side, reception from the middle of the packet can be handled.

  In addition, the reflector can further maintain the frame synchronization on the reflected wave reader side by arranging the in-frame position number in each frame, thereby reducing the possibility of causing frame synchronization loss. Become.

  According to the present invention, an excellent wireless communication system, a wireless communication apparatus, and a wireless communication system capable of suitably performing data transmission by the TDD method in an asymmetric transmission path having different transmission speeds in each direction between reflectors or reflected wave readers, and A wireless communication method and a computer program can be provided.

  Further, according to the present invention, in the asymmetric transmission path in which the transmission speed between the reflectors or the reflected wave readers is different, the influence of the low speed downlink is used by using the high speed uplink from the reflector to the reflected wave reader. Therefore, it is possible to provide an excellent wireless communication system, wireless communication apparatus, wireless communication method, and computer program capable of efficiently performing data transmission while suppressing a decrease in effective transmission speed due to the above.

  In addition, according to the present invention, retransmission is efficiently performed using a frame configuration in which a plurality of frames are concatenated and transmitted as one transmission burst in an asymmetric transmission path having different transmission speeds between reflectors or reflected wave readers. An excellent wireless communication system, wireless communication apparatus, wireless communication method, and computer program capable of performing control can be provided.

  According to the present invention, in the reflected wave transmission system having an asymmetric transmission rate, in the uplink that mainly performs data transmission, the effective transmission rate (throughput) of the uplink is reduced by connecting a plurality of frames and transmitting packets. It becomes possible to improve.

  Also, according to the present invention, when a plurality of frames are retransmitted by the stop-and-wait retransmission control method, when there are a plurality of retransmission frames, the same frames are not sequentially retransmitted but distributed in order. By filling the frames, the throughput can be improved when a burst-like error that easily occurs in the transmission path occurs.

  According to the present invention, since the communication time can be shortened by improving the throughput in the reflected wave transmission system, an effect of reducing power consumption can be obtained for battery-powered devices such as mobile devices.

  The present invention can be applied to other wireless communication systems that use a medium other than the reflected wave transmission path and use a fixed-length TDD system having an asymmetric transmission rate in each direction, and similarly improve throughput. Can be expected.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The present invention is a communication mode in which the transmission ratio occupies most of the communication between devices that are relatively limited to a short distance. The purpose is to realize transmission and mutual communication, and wireless transmission is performed using a reflected wave based on the back scatter method used in RFID.

  The RFID system itself is widely known in the art as an example of wireless communication means that can be applied only locally. Examples of the communication method between the tag and the reader / writer include an electromagnetic coupling method, an electromagnetic induction method, and a radio wave communication method. The present invention relates to a radio wave communication system using a microwave such as a 2.4 GHz band.

  FIG. 1 shows a configuration example of a reflected wave transmission system according to an embodiment of the present invention.

  The host 1 includes an RF function unit 11, a host communication control function unit 12, and a host function unit 13. The RF function unit 11 operates as a reflected wave reader in the reflected wave transmission system.

  The host function unit 13 is configured by a host device that processes or reproduces and outputs received data, such as a stationary home appliance such as a television, a monitor, a printer, a PC, a VTR, and a DVD player.

  On the other hand, the terminal 2 includes an RF function unit 21, a terminal communication function control function unit 22, and a terminal function unit 23. The RF function unit 21 operates as a reflector in the reflected wave transmission system.

  The terminal function unit 23 includes a mobile terminal device that is a transmission data supply source, such as a digital camera, a video camera, a mobile phone, a portable information terminal, and a portable music player.

  Data transmitted from the host function unit 13 is modulated by the modulation function unit 121 of the host communication control function unit 12 via the control interface 14. The modulated signal 15 is transmitted to the terminal 2 on the unmodulated carrier 31 generated by the carrier generation source 111 of the RF function unit 11. In general, ASK is used for the downlink from the host 1 to the terminal 2 in consideration of the ease of detection on the terminal 2 side. The RF function unit 21 of the terminal 2 receives the unmodulated carrier 31 and obtains the demodulated signal 25. The demodulated signal 25 is demodulated by the demodulation function unit 223 and is received by the terminal function unit 23 via the control interface 24.

  Data transmitted by the terminal function unit 23 of the terminal 2 is modulated by the modulation function unit 222 of the communication control function unit 22. The modulated signal 26 is placed on the reflected wave 32 obtained by detecting the unmodulated carrier 31 in the RF function unit 26 and transmitted to the host 1. The RF function unit 11 of the host 1 receives the reflected wave 32 and obtains the demodulated signal 16. The demodulated signal 16 is demodulated by the demodulation function unit 123 and received by the host function unit 13 via the control interface 14.

  Further, in addition to the data transmission / reception function described above, the host 1 and the terminal 2 can be provided by providing the protocol function units (121, 221) that mutually function in the host 1 and the terminal 2 in the respective communication control function units (12, 22). Protocol control such as connection and disconnection is realized.

  In the reflected wave transmission system, it is possible to drive the system with low consumption that the RF function unit 21 of the terminal 2 does not need a carrier generation source. Further, by performing multi-level modulation on the terminal side, high-speed communication from the terminal to the host direction can be realized.

  The terminal 1 is, for example, a digital still camera or a digital video camera, and the host 2 is, for example, a television or a printer. A still image or a video is uploaded from the terminal 1 to the host 2 and displayed, printed out, etc. Is assumed to be performed.

  In the uplink from the terminal 2 to the host 2, a low bit rate modulation scheme such as ASK or BPSK is common, but the gist of the present invention is not limited to this. At the time of modulation of the reflected wave, in addition to the operation of load impedance such as antenna termination processing, a phase difference is given on the signal path along which the reflected wave reciprocates. A modulation scheme can be realized. For example, Japanese Patent Application No. 2003-352223 already assigned to the present applicant discloses a back scatter type communication system incorporating QPSK modulation processing.

  On the other hand, the modulation in the host 1 uses ASK in consideration of the ease of detection on the terminal 2 side (described above). For this reason, the downlink from the host 1 to the terminal 2 has a low data rate, and the reflected wave transmission system has an asymmetric transmission line with different transmission rates for the uplink and the downlink.

  In an asymmetric reflected wave transmission system in which the transmission speed is different in each direction, when a retransmission control method in which transmission acknowledgment is exchanged by Ack or Nack for each frame in TDD transmission is applied, Since the time ratio becomes high, there is a problem that the uplink transmission rate becomes insufficient.

  Therefore, in the present embodiment, a frame configuration in which a plurality of frames are concatenated and transmitted as one transmission burst is used in the uplink that mainly performs data transmission. By transmitting a packet by concatenating a plurality of frames, it is possible to improve the effective transmission rate (throughput) of the uplink.

  On the reflected wave reader side, retransmission control is performed for an erroneous frame. For retransmission control, partial retransmission is performed in frame units by a stop-and-wait retransmission control method for error correction.

  Here, it is assumed that a retransmission control method using a frame configuration in which a plurality of frames are concatenated and transmitted as one transmission burst is applied. In such a case, when sending the same number of frames in a fixed number of times, if the same frame is sent multiple times at a time, the frame is retransmitted multiple times when a burst error occurs due to an error in the transmission path. In spite of this, it may cause an error again, so the retransmission efficiency is poor. In particular, transmission path errors in a reflected wave transmission system are more susceptible to burst errors because they are dominant.

  FIG. 2 illustrates the problem of retransmission control in a reflected wave transmission system. It is assumed that packets (a), (b), (c), and (d) are transmitted and received in time series.

  In the figure, since the first frame and the third frame have failed to be transmitted in the first packet (a), the first and third retransmissions are requested in (b). The retransmission packet (c) is transmitted by filling the first frame and the third frame for 5 frames from the reflector side. At this time, it is assumed that the first frame is sent out three times and the second frame is sent out only twice. Here, when the forward part of the packet is erroneous by 3 frames due to a burst error, the first frame fails to be transmitted again, and therefore retransmission is performed again, resulting in poor transmission efficiency.

  Therefore, in this embodiment, when a plurality of frames are retransmitted by the stop & wait retransmission control method, the retransmitted frames are repeatedly transmitted alternately. In other words, when there are multiple retransmitted frames, the same frame is not retransmitted continuously, but the frames are packed so that they are distributed in order. Throughput can be improved.

  FIG. 3 schematically shows a transmission sequence for transmitting packets in the uplink from the terminal 2, that is, the reflector, to the host 1, that is, the reflected wave reader.

  In the example shown in the figure, in order to improve the uplink transmission time ratio, a plurality of frames are connected by uplink packets (5 connections in the figure). In the downlink, the Ack or Nack for each of the five concatenated frames is shown, and only a wrong frame is partially requested for retransmission.

  FIG. 4 shows the configuration of each frame in the transmission sequence shown in FIG. 3 in detail.

  One frame includes a preamble for synchronizing modulation, a frame synchronization bit (unique word) for frame synchronization, frame information (alternate bit, frame number, in-packet position number, and frame parameter, Data length etc.), data (payload), error detection bits and error correction bits.

  In the example shown in FIG. 4, the case where data and error correction bits are separated as in Reed-Solomon code, for example, is taken up. However, depending on the error correction method, data (raw information) such as a convolutional code is taken up. ) And error correction bits may not be separated.

  In the first transmission packet, transmission is performed in the above frame configuration in order from the first frame to the fifth frame. Depending on the system configuration, a preamble can be added only at the forefront of a transmission packet to make it easier to synchronize modulation at the beginning of the packet.

  One packet (a lump in which five frames are connected in the illustrated example) is sent from the terminal 2, that is, the reflector side, and this is received by the host 1, that is, the reflected wave reader side. On the host 1 side, error correction and error detection are performed for each frame, and a retransmission request for the frame with an error is put in frame information and transmitted as a downlink packet.

  FIG. 5 shows an example of the time ratio between the uplink and the downlink when the TDD operation is performed by the transmission sequence shown in FIG. 3 using the frame configuration shown in FIG.

  While the uplink transmission rate is 10 Mbps, the downlink transmission rate is 1 Mbps, and the downlink is slow. Therefore, the proportion of the actual communication time is large, and the time allocated for actual data transmission is small. Become. On the other hand, as can be seen from the figure, the uplink occupancy time is improved and the actual data transmission throughput can be improved by connecting the frames with the packets on the uplink side. .

  FIG. 6 shows an example of a transmission sequence that realizes the stop & way and retransmission control method in the reflected wave transmission system according to the present embodiment.

  The stop-and-wait retransmission control method is a method of retransmitting the same packet until delivery confirmation can be performed for one packet. In the present embodiment, a function of connecting frames and enabling partial retransmission control for each frame is provided. In addition, because of the instability due to the reflected wave transmission path, the reflected wave reader side can receive in frame units for reception from the middle of the packet, and if one frame can be received, frame synchronization can be maintained. It has a function. Furthermore, in consideration of a burst-like error in the reflected wave transmission line at the time of retransmission, a function is provided in which retransmission frames are sequentially packed by a fixed number of frames and transmitted.

  As an example of the transmission sequence shown in FIG. 6, the packet (a) is transmitted from the reflector side. On the other hand, the reflected wave reader side has failed to receive the first and third frames included in the packet. Therefore, the reflected wave reader side requests retransmission of the first and third frames in the Ack or Nack packet (b).

  On the reflector side, since the first and third frames are requested to be retransmitted from the reflected wave reader, the first and third frames are alternately converted into five connected numbers and transmitted as one transmission packet (c).

  On the reflected wave reader side, even if reception of 3 frames from the beginning of the transmission packet fails, reception from the middle is possible because the preamble and frame synchronization bit are arranged in each frame. That is, data reception for five frames (one packet) can be completed by receiving the third frame (position 4) and the first frame (position 5).

  Further, since the reflector describes information indicating the position number in the packet in each frame included in the packet as a transmission burst, the reflected wave reader can maintain frame synchronization.

  FIG. 7 shows an example of how to pack frames of retransmission packets with respect to error frames. On the reflection side (high-speed data transmission side), the frame numbers that received the retransmission request are retransmitted in order. When the number of connections is not reached, retransmission is repeated in order until the number of connections is reached again.

  The left column of the table shows the error status (frames requested for retransmission), and the right column of the table shows how to pack the transmission frames for 5 frames at that time. Is done.

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiment without departing from the gist of the present invention.

  In the present specification, the embodiment of the present invention has been described by taking as an example the transmission of an unmodulated carrier from the reading device side and the reflected wave transmission system that modulates the reflected wave with the transmission data on the transmission device side. The gist of the present invention is not limited to this. Even in other wireless communication systems that use media other than reflected wave transmission, by applying the present invention to an asymmetric transmission path with different transmission speeds in each direction, a high-speed uplink can be used and a low-speed transmission system can be used. It is possible to efficiently transmit data while suppressing a decrease in effective transmission rate due to the influence of the downlink. That is, even when the present invention is applied to any form of communication system in which the transmission rate is asymmetric, retransmission control is performed with high transmission efficiency by using a frame configuration in which a plurality of frames are concatenated and transmitted as one transmission burst. Will be able to.

  In short, the present invention has been disclosed in the form of exemplification, and the description of the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims should be taken into consideration.

FIG. 1 is a diagram showing a configuration example of a reflected wave transmission system according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the problem of retransmission control in the reflected wave transmission system. FIG. 3 is a diagram schematically showing a transmission sequence for transmitting packets in the uplink from the terminal 2, that is, the reflector, to the host 1, that is, the reflected wave reader. FIG. 4 is a diagram showing in detail the configuration of each frame in the transmission sequence shown in FIG. FIG. 5 is a diagram illustrating an example of the time ratio between the uplink and the downlink when the TDD operation is performed according to the transmission sequence illustrated in FIG. 3 using the frame configuration illustrated in FIG. FIG. 6 is a diagram showing an example of a transmission sequence that realizes the stop & way and retransmission control method in the reflected wave transmission system according to the present invention. FIG. 7 is a diagram illustrating an example of how to pack frames of a retransmission packet with respect to an error frame. FIG. 8 is a diagram schematically showing a system configuration example using reflected wave transmission. FIG. 9 is a diagram illustrating an operation example of the reflected wave transmission system employing the TDD scheme. FIG. 10 is a diagram showing an example of a transmission frame configuration in the reflected wave transmission system. FIG. 11 is a diagram showing an example of a TDD communication operation using the frame shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Host 11 ... RF function part 111 ... Carrier generation source 12 ... Communication control function part 121 ... Modulation function part 122 ... Modulation function part 123 ... Demodulator function part 13 ... Host apparatus 14 ... Control interface 2 ... Terminal 21 ... RF function Unit 22 ... Communication control function unit 221 ... Protocol function unit 222 ... Modulation function unit 223 ... Demodulation function unit 23 ... Terminal function unit 24 ... Control interface

Claims (47)

  1. A wireless communication system that performs reflected wave transmission by transmitting an unmodulated carrier from the reflected wave reader side and modulating the reflected wave according to transmission data on the reflector side,
    Adopting a time division multiplex system with a fixed frame length during data communication, configured by connecting a plurality of frames to one transmission packet in an uplink transmission burst from the reflector to the reflected wave reader direction,
    A wireless communication system.
  2. When an error occurs in a frame included in the received packet on the reflected wave reader side, partial retransmission is performed in units of frames by a stop-and-wait retransmission control method for error correction.
    The wireless communication system according to claim 1.
  3. The reflector repeatedly transmits a frame to be retransmitted alternately when transmitting the erroneous frame by the number of fixed connections on the reflected wave reader side.
    The wireless communication system according to claim 2.
  4. The reflector attaches a frame number and an alternating bit to each frame constituting the transmission burst,
    The wireless communication system according to claim 1.
  5. The reflector attaches a transmission position in the transmission burst to each frame constituting the transmission burst.
    The wireless communication system according to claim 4.
  6. The reflected wave reader makes a retransmission request including a frame including an area for displaying an erroneous frame included in the received packet as a bitmap in a transmission burst to the opposite device.
    The wireless communication system according to claim 1.
  7. A wireless communication system for performing bidirectional communication,
    Adopting a time division multiplex system with a fixed frame length during data communication, and configuring one transmission packet by linking a plurality of frames in a transmission burst in at least one-way communication,
    A wireless communication system.
  8. When performing partial retransmission in units of frames by the stop & wait retransmission control method for error correction, the frames to be retransmitted are alternately transmitted in a fixed number of connections.
    The wireless communication system according to claim 7.
  9. A frame number and an alternating bit are attached to each frame constituting the transmission burst.
    The wireless communication system according to claim 7.
  10. A transmission position in the transmission burst is attached to each frame constituting the transmission burst.
    The wireless communication system according to claim 9.
  11. On the data receiving side, a retransmission request including a frame including an area for displaying an erroneous frame included in the received packet as a bitmap in a transmission burst to the opposite device is performed.
    The wireless communication system according to claim 7.
  12. A wireless communication device that performs reflected wave communication using modulation of a reflected wave with respect to an unmodulated carrier received from a reflected wave reader,
    A transmission means for receiving an unmodulated carrier from the reflected wave reader and transmitting a packet as a reflected wave modulated according to transmission data;
    Receiving means for receiving a packet from a communication partner;
    Communication control means for generating a transmission packet and processing a reception packet;
    The communication control means adopts a time division multiplexing method in which the frame length is fixed during data communication, concatenates a plurality of frames and transmits them as one transmission burst.
    A wireless communication apparatus.
  13. In response to a retransmission request from a communication partner, further comprises retransmission control means for performing partial retransmission in units of frames.
    The wireless communication apparatus according to claim 12.
  14. The retransmission control means repeatedly transmits a frame to be retransmitted alternately when transmitting a fixed number of erroneous frames on the opposite reflected wave reader side,
    The wireless communication apparatus according to claim 13.
  15. The communication control means or the retransmission control means attaches a frame number and an alternating bit to each frame constituting a transmission burst,
    The wireless communication apparatus according to claim 14.
  16. The communication control means or the retransmission control means attaches a transmission position in the transmission burst to each frame constituting the transmission burst.
    The wireless communication apparatus according to claim 15.
  17. A wireless communication device that performs reflected wave communication using modulation of a reflected wave from a reflector with respect to an unmodulated carrier,
    Transmission means for transmitting an unmodulated carrier and a packet;
    Receiving means for receiving a packet on a reflected wave from a communication partner for an unmodulated carrier transmitted by the transmitting means;
    Communication control means for generating a transmission packet and processing a reception packet;
    The communication control means adopts a time division multiplexing method in which the frame length is fixed during data communication, and receives a packet transmitted as one transmission burst by concatenating a plurality of frames.
    A wireless communication apparatus.
  18. When there is an error in a frame included in the received packet, it further includes retransmission control means for making a retransmission request by a stop-and-wait retransmission control method for error correction.
    The wireless communication apparatus according to claim 17.
  19. The retransmission control means makes a retransmission request including a frame including an area for displaying an erroneous frame included in the received packet as a bitmap in a transmission burst to the opposite device.
    The wireless communication apparatus according to claim 18.
  20. A wireless communication device that performs bidirectional communication,
    A communication means for transmitting and receiving packets;
    Communication control means for generating a transmission packet and processing a reception packet;
    The communication control means adopts a time division multiplexing method in which the frame length is fixed during data communication, concatenates a plurality of frames and transmits them as one transmission burst.
    A wireless communication apparatus.
  21. In response to a retransmission request from a communication partner, further comprises retransmission control means for performing partial retransmission in units of frames.
    The wireless communication apparatus according to claim 20.
  22. The retransmission control means repeatedly transmits a frame to be retransmitted alternately when transmitting the erroneous frame by the fixed connection number on the communication partner side,
    The wireless communication apparatus according to claim 21, wherein:
  23. The communication control means or the retransmission control means attaches a frame number and an alternating bit to each frame constituting a transmission burst,
    The wireless communication apparatus according to claim 22.
  24. The communication control unit or the retransmission control unit attaches a transmission position in the transmission burst to each frame constituting the transmission burst.
    24. The wireless communication apparatus according to claim 23.
  25. A wireless communication device that performs bidirectional communication,
    A communication means for transmitting and receiving packets;
    Communication control means for generating a transmission packet and processing a reception packet;
    The communication control means adopts a time division multiplexing method in which the frame length is fixed during data communication, and receives a packet transmitted as one transmission burst by concatenating a plurality of frames.
    A wireless communication apparatus.
  26. When there is an error in a frame included in the received packet, it further includes retransmission control means for making a retransmission request by a stop-and-wait retransmission control method for error correction.
    26. The wireless communication apparatus according to claim 25.
  27. The retransmission control means performs a retransmission request including a frame including an area for displaying an erroneous frame included in the received packet as a bitmap in a transmission burst to the opposite device.
    27. The wireless communication apparatus according to claim 26.
  28. A wireless communication method for performing reflected wave communication using modulation of a reflected wave with respect to an unmodulated carrier received from a reflected wave reader,
    Receiving a non-modulated carrier and a packet from the reflected wave reader;
    A transmission step of adopting a time division multiplexing method with a fixed frame length during data communication, and connecting a plurality of frames as a reflected wave modulated according to transmission data and transmitting as one transmission burst;
    A wireless communication method comprising:
  29. A resending step of performing partial resending in units of frames in response to a resending request from a communication partner;
    The wireless communication method according to claim 28, wherein:
  30. In the retransmission step, when transmitting the erroneous frame by the fixed link number on the communication partner side, the frame to be retransmitted is repeatedly transmitted alternately.
    30. The wireless communication method according to claim 29.
  31. In the transmission step or the retransmission step, a frame number and an alternating bit are attached to each frame constituting the transmission burst,
    The wireless communication method according to claim 30, wherein:
  32. In the transmission step or the retransmission step, a transmission position in the transmission burst is attached to each frame constituting the transmission burst.
    The wireless communication method according to claim 31, wherein:
  33. A wireless communication method for performing reflected wave communication using modulation of a reflected wave from a reflector with respect to an unmodulated carrier,
    A transmission step of transmitting an unmodulated carrier;
    A reception step of receiving a packet on a reflected wave from a communication partner for an unmodulated carrier
    In the reception step, a time division multiplexing method in which the frame length is fixed during data communication is adopted, and a plurality of frames are connected to receive a packet transmitted as one transmission burst.
    A wireless communication method.
  34. A retransmission request step for performing a retransmission request according to a stop-and-wait retransmission control scheme for error correction when an error occurs in a frame included in the received packet;
    34. The wireless communication method according to claim 33.
  35. In the retransmission request step, a retransmission request including a frame including an area for displaying an erroneous frame included in the received packet as a bitmap in a transmission burst to the opposite device is performed.
    The wireless communication method according to claim 34, wherein:
  36. A wireless communication method for performing bidirectional communication,
    Adopting a time division multiplex method with a fixed frame length during data communication, comprising a transmission step of concatenating a plurality of frames and transmitting as one transmission burst,
    A wireless communication method.
  37. A resending step of performing partial resending in units of frames in response to a resending request from a communication partner;
    The wireless communication method according to claim 36.
  38. In the retransmission step, when transmitting the erroneous frame by the fixed link number on the communication partner side, the frame to be retransmitted is repeatedly transmitted alternately.
    The wireless communication method according to claim 37, wherein:
  39. In the transmission step or the retransmission step, a frame number and an alternating bit are attached to each frame constituting the transmission burst,
    The wireless communication method according to claim 38, wherein:
  40. In the transmission step or the retransmission step, a transmission position in the transmission burst is attached to each frame constituting the transmission burst.
    40. The wireless communication method according to claim 39.
  41. A wireless communication method for performing bidirectional communication,
    Adopting a time division multiplexing method with a fixed frame length during data communication, comprising a reception step of concatenating a plurality of frames and receiving a packet transmitted as one transmission burst,
    A wireless communication method.
  42. A retransmission request step for performing a retransmission request according to a stop-and-wait retransmission control scheme for error correction when an error occurs in a frame included in the received packet;
    42. The wireless communication method according to claim 41, wherein:
  43. In the retransmission request step, a retransmission request including a frame including an area for displaying an erroneous frame included in the received packet as a bitmap in a transmission burst to the opposite device is performed.
    The wireless communication method according to claim 42, wherein:
  44. A computer program written in a computer readable format to execute processing on a computer system for performing reflected wave communication using modulation of reflected waves with respect to an unmodulated carrier received from a reflected wave reader,
    Receiving a non-modulated carrier and a packet from the reflected wave reader;
    A transmission step of adopting a time division multiplexing method with a fixed frame length during data communication, and connecting a plurality of frames as a reflected wave modulated according to transmission data and transmitting as one transmission burst;
    A computer program comprising:
  45. A computer program written in a computer-readable format to execute processing on a computer system for performing reflected wave communication using modulation of a reflected wave from a reflector with respect to an unmodulated carrier,
    A transmission step of transmitting an unmodulated carrier;
    A reception step of receiving a packet on a reflected wave from a communication partner for an unmodulated carrier
    In the reception step, a time division multiplexing method in which the frame length is fixed during data communication is adopted, and a plurality of frames are connected to receive a packet transmitted as one transmission burst.
    A computer program comprising:
  46. A computer program written in a computer-readable format so as to execute processing for bidirectional communication on a computer system,
    During data communication, adopting a time division multiplexing method with a fixed frame length, a transmission step of concatenating a plurality of frames and transmitting as one transmission burst;
    In response to a retransmission request from a communication partner, when performing partial retransmission in units of frames, a retransmission step of repeating a frame to be retransmitted alternately and transmitting frames for a fixed number of connections;
    A computer program comprising:
  47. A computer program written in a computer-readable format so as to execute processing for bidirectional communication on a computer system,
    A reception step of receiving a packet transmitted as one transmission burst by concatenating a plurality of frames by adopting a time division multiplexing method with a fixed frame length during data communication;
    A retransmission request step for performing a retransmission request by a stop-and-wait retransmission control method for error correction when an error occurs in a frame included in the received packet;
    A computer program comprising:
JP2004187407A 2004-06-25 2004-06-25 System, apparatus, and method for radio communication, and computer program Pending JP2006013843A (en)

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