JP2009044564A - Communication method, and base station device and terminal device utilizing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the number of times of transmitting a correction instruction signal. <P>SOLUTION: A reception timing acquisition unit 36 receives a packet signal from a terminal device. A derivation unit 38 derives an error between timing in which the packet signal is received and timing scheduled to receive the relevant packet signal. On the basis of the error derived in the derivation unit 38, an instruction unit 40 instructs the terminal device to adjust timing in transmitting the packet signal. In particular, the instruction unit 40 instructs the terminal device to autonomously adjust timing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to communication technology, and more particularly to a communication method for transmitting and receiving packet signals at a predetermined timing, and a base station apparatus and terminal apparatus using the communication method.

In a wireless communication system such as a second generation cordless telephone system, a plurality of base station apparatuses are installed. In addition, each base station apparatus transmits and receives packet signals to and from terminal apparatuses by time division multiplexing (TDMA). For this reason, if frame synchronization of the packet signal of each base station apparatus is not established, a predetermined time slot is interfered by a packet signal from an adjacent base station apparatus, and the time slot cannot be used. As a result, the radio waves cannot be effectively used. Therefore, frame synchronization between the base station apparatuses must be established (see, for example, Patent Document 1).
JP-A-9-148978

  In addition to the frame synchronization between the base station devices as described above, frame synchronization between the base station device and the terminal device must be established in order to execute communication. Generally, the terminal device generates its own frame timing and transmits / receives a packet signal at the frame timing so as to synchronize with the frame timing generated by the base station device. Further, in order to improve the accuracy of frame synchronization between the base station device and the terminal device, the base station device estimates the frame timing shift in the timing device based on the packet signal received from the terminal device. The terminal device is instructed to perform correction according to the deviation. On the other hand, the terminal device corrects the frame timing according to the instruction. Considering the stability of the wireless communication system, the correction amount must be reduced to some extent. Under such circumstances, if the error between the frame timing generated by the terminal device and the frame timing generated by the base station device is large, a correction instruction by the base station device is transmitted a plurality of times. As a result, a period until the frame timing synchronization between the base station apparatus and the terminal apparatus is established becomes long.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a communication technique that reduces the number of times of transmission of a correction instruction signal.

  In order to solve the above problems, a base station apparatus according to an aspect of the present invention is configured to receive a packet signal from a terminal apparatus, a timing at which the packet signal is received at the receiving section, and reception of the packet signal A deriving unit for deriving an error with respect to the timing, and an instructing unit for instructing the terminal device to adjust the timing when transmitting the packet signal based on the error derived by the deriving unit. The instruction unit instructs the terminal device to adjust the timing autonomously.

  Another aspect of the present invention is a terminal device. The apparatus includes: a receiving unit that receives an instruction regarding timing when transmitting a packet signal from the base station apparatus; and an adjustment unit that adjusts timing when transmitting the packet signal according to the instruction received in the receiving unit; A transmission unit that transmits the packet signal to the base station apparatus at a timing adjusted by the adjustment unit. The adjustment unit adjusts the timing according to the adjustment amount when the instruction received at the reception unit is a timing adjustment amount, and the base station when the instruction received at the reception unit is to adjust the timing autonomously, Timing is adjusted by predicting the amount of propagation delay to the device.

  Yet another embodiment of the present invention is a communication method. According to this method, a step of receiving a packet signal from a terminal device, a step of deriving an error between the timing at which the packet signal is received and the timing at which the packet signal is scheduled to be received, and the derived error are used. And a step of instructing the terminal device to adjust the timing at which the packet signal is transmitted. The instructing step instructs the terminal device to adjust the timing autonomously.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  The number of correction instruction signal transmissions can be reduced.

  Before describing the present invention in detail, an outline will be described. An embodiment of the present invention relates to a communication system including at least a base station apparatus and a terminal apparatus, such as a communication system compliant with the IEEE 802.16 / 16e standard. The communication system connects a plurality of terminal devices by at least TDMA. The base station apparatus forms a frame, and the terminal apparatus forms a frame so as to be synchronized with the frame of the base station apparatus. Further, the base station apparatus designates a predetermined timing in the frame and instructs the terminal apparatus to use the timing. Here, the timing includes reception timing and transmission timing. The terminal device receives a packet signal from the base station device at a designated reception timing among frames generated by itself, and transmits the packet signal to the base station device at a designated transmission timing. Furthermore, the base station apparatus allocates a predetermined period as a transmission timing to one terminal apparatus, and allocates a period following the period as a transmission timing to another terminal apparatus.

  At this time, if the frames generated by the terminal devices are shifted, the packet signals overlap between the two terminal devices, and interference occurs between them. In order to reduce the influence of such interference, when the base station apparatus receives a packet signal from the terminal apparatus, the base station apparatus estimates a frame timing shift formed in the terminal apparatus, and sets a correction amount according to the estimation result. Notify the terminal device. At this time, if the correction amount is large, the amount of change in the frame timing in the terminal device becomes large, which may reduce the stability of the communication system. For this reason, the correction amount must be reduced to such an extent that the stability of the communication system does not deteriorate. Under such circumstances, if the frame timing shift in the terminal device is large, the number of correction amount transmissions by the base station device increases. As a result, the traffic is reduced and the period until the timing synchronization is established becomes long. In order to cope with this, the communication system according to the embodiment of the present invention executes the following processing.

  When the base station apparatus receives the packet signal from the terminal apparatus, the base station apparatus estimates a frame timing shift formed in the terminal apparatus. Further, if the amount of deviation is not larger than the threshold value, the base station apparatus notifies the terminal apparatus of a correction amount corresponding to the estimation result, as described above. On the other hand, the base station apparatus instructs the terminal apparatus to autonomously adjust the frame timing when the amount of deviation is larger than the threshold value. The terminal device adjusts the frame timing itself, and transmits a packet signal at the adjusted frame timing. Thereafter, when the amount of deviation does not become larger than the threshold value, the base station device notifies the terminal device of the correction amount.

  FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. The communication system 100 includes a base station device 10 and a terminal device 12. Here, it is assumed that the communication system 100 conforms to the IEEE 802.16 / 16e standard. These are also called WiMAX (World Interoperability for Microwave Access) (trademark). Here, the details of WiMAX are omitted. The base station apparatus 10 repeatedly forms a frame. While using the formed frame, the base station apparatus 10 executes time division multiple access (TDMA) in the time domain, and executes OFDMA (Orthogonal Frequency Division Multiple Access) in the frequency domain. Through such processing, the base station device 10 connects a plurality of terminal devices 12. Base station apparatus 10 transmits data received from a network (not shown) to terminal apparatus 12 on the downlink, and transmits data received from terminal apparatus 12 to the network on the uplink.

  OFDMA is a technique for frequency-division multiplexing a plurality of terminal devices using OFDM. In such OFDMA, subchannels are formed by a plurality of subcarriers, and the plurality of subchannels are frequency-division-divided. Therefore, each frame is formed by frequency division multiplexing of a plurality of subchannels, and each subchannel is formed by time division multiplexing of a plurality of time slots. Each subchannel is formed by a multicarrier signal. Here, the number of subcarriers included in each subchannel is variable. In the following description, the description will focus on frame timing. Therefore, the description regarding the subchannel is omitted, and this corresponds to the operation in one subchannel.

  The terminal device 12 receives the packet signal from the base station device 10 at the reception timing specified by the base station device 10. Here, the reception timing corresponds to a time slot in which a packet signal transmitted from the base station apparatus 10 is to be received. In addition, the terminal device 12 transmits a packet signal to the base station device 10 at a transmission timing designated by the base station device 10. As a premise of the above processing, the terminal device 12 receives a signal from the base station device 10 and generates a frame by itself based on the signal. Although details of a method of forming a frame are omitted, for example, the terminal device 12 detects the start timing of the frame and operates a built-in counter over a predetermined frame period.

  In addition, the terminal device 12 receives a frame timing correction amount from the base station device 10 and corrects the frame timing according to the correction amount. Note that the terminal device 12 corrects the frame timing by another method other than such processing, and this will be described later. Furthermore, the terminal device 12 receives the packet signal at a timing corresponding to the designated reception timing in the generated frame, and transmits the packet signal at a timing corresponding to the designated transmission timing.

  FIG. 2 shows the configuration of the base station apparatus 10. The base station apparatus 10 includes an RF unit 20, an AD unit 22, an FFT unit 24, a demodulation unit 26, a modulation unit 28, an IFFT unit 30, a DA unit 32, and a control unit 34. The control unit 34 includes a reception timing acquisition unit 36, a derivation unit 38, and an instruction unit 40.

  As a reception process, the RF unit 20 performs frequency conversion on a radio frequency multicarrier signal received from a terminal device 12 (not shown) to generate a baseband multicarrier signal. Here, the multicarrier signal is formed so as to include a plurality of subchannels according to WiMAX, and corresponds to a packet signal. Further, the RF unit 20 outputs a baseband multicarrier signal to the AD unit 22. In general, a baseband multicarrier signal is formed by an in-phase component and a quadrature component, and therefore should be transmitted by two signal lines. For the sake of clarity, a single signal line is used here. Only. The RF unit 20 also includes an LNA (Low Noise Amplifier) and AGC.

  As a transmission process, the RF unit 20 performs frequency conversion on the baseband multicarrier signal input from the AD unit 22 to generate a radiofrequency multicarrier signal. Further, the RF unit 20 transmits a radio frequency multicarrier signal. The RF unit 20 transmits a multicarrier signal while using the same radio frequency band as the received multicarrier signal. In other words, TDD (Time Division Duplex) is used. The RF unit 20 also includes a PA (Power Amplifier).

  The AD unit 22 inputs a baseband multicarrier signal from the RF unit 20. Further, the AD unit 22 performs analog-digital conversion on the baseband multicarrier signal, and outputs the baseband multicarrier signal as a digital signal to the FFT unit 24. The FFT unit 24 inputs a baseband multicarrier signal from the AD unit 22. Since the baseband multicarrier signal is a time domain signal, the FFT unit 24 converts the time domain signal into the frequency domain by FFT. The FFT unit 24 executes symbol synchronization, that is, FFT window setting, and also deletes the guard interval.

  Since a known technique may be used for symbol synchronization or the like, description thereof is omitted here. A frequency domain multicarrier signal can also be said to be a multicarrier signal formed by a plurality of subcarriers. The FFT unit 24 outputs the baseband multicarrier signal converted into the frequency domain to the demodulation unit 26. Here, since the signal in the frequency domain includes a plurality of subcarriers, when associating each subcarrier with a signal line, a signal line corresponding to the number of subcarriers should be shown in FIG. . However, only one signal line is shown here for the sake of clarity.

  The demodulator 26 receives a baseband multicarrier signal from the FFT unit 24. The demodulator 26 demodulates the multicarrier signal in units of subcarriers. Since a known technique may be used for demodulation, the description is omitted here. When a multicarrier signal is composed of a plurality of subchannels, each subchannel may be assigned to different terminal devices 12. In such a case, the demodulation unit 26 aggregates the demodulation results for each terminal device 12. Further, the demodulator 26 outputs the demodulation result to a network (not shown). At that time, the demodulator 26 outputs a demodulation result according to information for identifying the destination, for example, an IP (Internet Protocol) address.

  The modulation unit 28 inputs data for the terminal device 12 from a network (not shown). The modulation unit 28 allocates data to the subchannel according to the instruction from the control unit 34. As a result, a multi-carrier signal in the frequency domain is formed. The modulation unit 28 modulates the multicarrier signal in units of subcarriers. The modulation unit 28 outputs the modulated multicarrier signal to the IFFT unit 30.

  The IFFT unit 30 inputs a frequency domain multicarrier signal from the modulation unit 28. The IFFT unit 30 converts a frequency domain signal into a time domain by IFFT, and generates a time domain multicarrier signal. The IFFT unit 30 also adds a guard interval, but a description thereof is omitted here. The IFFT unit 30 outputs a time-domain multicarrier signal to the DA unit 32. The DA unit 32 inputs a time-domain multicarrier signal from the IFFT unit 30. The DA unit 32 performs analog-digital conversion on the multi-carrier signal in the time domain, and outputs the multi-carrier signal as an analog signal to the FFT unit 24. Here, the multicarrier signal as an analog signal corresponds to a baseband multicarrier signal.

  The control unit 34 controls the operation of the entire base station apparatus 10. For example, when the terminal device 12 is newly connected, the control unit 34 executes the following process. The control unit 34 periodically transmits downlink parameters from the modulation unit 28 to the DA unit 32 and the RF unit 20. The downlink parameters are stored in a DCD (Downlink Channel Descriptor) in the packet signal. In addition, the control unit 34 periodically transmits uplink parameters from the modulation unit 28 to the DA unit 32 and the RF unit 20. This uplink parameter is stored in a UCD (Uplink Channel Descriptor) in the packet signal. The control unit 34 receives an RNG-REQ (Ranging Request) from the terminal device 12 (not shown) via the demodulation unit 26 from the RF unit 20.

  When receiving the RNG-REQ, the control unit 34 derives an adjustment amount of the frame timing in the terminal device 12. Further, the control unit 34 includes the derived adjustment amount in an RNG-RSP (Ranging Response), and transmits the RNG-RSP from the modulation unit 28 via the DA unit 32 and the RF unit 20. The process of synchronizing the frame timing of the terminal device 12 while using the RNG-REQ and the RNG-RSP is called a ranging process. Note that the transmission between the RNG-REQ and the RNG-RSP is repeated until the frame timing shift of the terminal device 12 is reduced to some extent, that is, until the frame timing synchronization of the terminal device 12 is established. After the frame timing synchronization is established, the control unit 34 authenticates the terminal device 12 by executing processing in accordance with a PKM (Private Key Management) protocol.

  In addition, the control unit 34 exchanges an encryption key (KEK: Key Encryption Key) with the terminal device 12. At that time, the RF unit 20 to the DA unit 32 are used. Subsequently, the control unit 34 receives a REG-REQ (Registration Request) from the terminal device 12 via the demodulation unit 26 from the RF unit 20. The control unit 34 registers the terminal device 12 and generates a REG-RSP (Registration Response) as a result. The control unit 34 transmits REG-RSP from the modulation unit 28 via the DA unit 32 and the RF unit 20.

  On the premise of the above description, each unit constituting the control unit 34 executes the following processing. The reception timing acquisition unit 36 acquires the reception timing of the packet signal from the terminal device 12 (not shown) from the RF unit 20 through the demodulation unit 26. The packet signal corresponds to the aforementioned RNG-REQ. The reception timing is a timing at a frame generated in the base station apparatus 10. Here, the reception timing may be indicated as a predetermined period so as to indicate the length of the packet signal, or may be indicated as a predetermined point so as to indicate the head of the packet signal. For example, when one frame is formed with sampling points from “1” to “N”, the leading timing of the packet signal is indicated as “i”. Here, “i” is a number between “1” and “N”. The reception timing acquisition unit 36 outputs the reception timing to the derivation unit 38.

  The deriving unit 38 receives the reception timing from the reception timing acquisition unit 36. In addition, the deriving unit 38 acquires the timing (hereinafter referred to as “scheduled timing”) at which reception of the packet signal is scheduled from the control unit 34. Such a scheduled timing is determined in advance as a timing for receiving the RNG-REQ. Furthermore, the deriving unit 38 derives an error between the reception timing and the scheduled timing. The deriving unit 38 outputs an error.

  The instruction unit 40 receives an error from the derivation unit 38. The instruction unit 40 compares the error with a predetermined threshold value. When the error is not larger than the threshold value, the instructing unit 40 derives the timing adjustment amount according to the error. Since the timing adjustment amount may be derived by a known technique, a description thereof is omitted here. For example, a value that brings the error closer to “0” is derived as the adjustment amount. In addition, the instruction unit 40 includes the adjustment amount in the RNG-RSP. The instruction unit 40 transmits RNG-RSP from the modulation unit 28 via the DA unit 32 and the RF unit 20. The above process corresponds to the above-described ranging process.

  On the other hand, when the error is larger than the threshold value, the instruction unit 40 includes in the RNG-RSP that the terminal device 12 autonomously adjusts the timing. Here, to adjust the timing autonomously corresponds to instructing the terminal device 12 to adjust the timing without showing a specific adjustment amount. When receiving such an instruction, the terminal apparatus 12 generates a frame again at a new timing, and transmits an RNG-REQ to the base station apparatus 10. Through these processes, the instruction unit 40 instructs the terminal device 12 to adjust the timing when transmitting the packet signal, based on the error derived by the deriving unit 38.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it is realized by a program having a communication function loaded in the memory. Describes functional blocks realized by collaboration. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 3 shows the configuration of the terminal device 12. The terminal device 12 includes an RF unit 50, an AD unit 52, an FFT unit 54, a demodulation unit 56, a modulation unit 58, an IFFT unit 60, a DA unit 62, and a control unit 64. The control unit 64 includes a reception unit 66, an adjustment unit 68, and a prediction unit 70.

  The RF unit 50 to the DA unit 62 execute the same processing as the RF unit 20 to the DA unit 32 in FIG. Therefore, the description of the RF unit 50 to the DA unit 62 is omitted here. The control unit 64 controls the operation of the entire terminal device 12. Although the operation when the base station apparatus 10 newly connects the terminal apparatus 12 has already been described, the control unit 64 controls the terminal apparatus 12 so that the terminal apparatus 12 performs processing as described.

  The reception unit 66 receives the RNG-RSP from the base station apparatus 10 via the RF unit 50 and the demodulation unit 56. As described above, the RNG-RSP includes an instruction regarding adjustment of frame timing. Here, the instruction related to the adjustment of the frame timing corresponds to the instruction related to the timing when transmitting the packet signal. It is assumed that the control unit 64 is transmitting RNG-REQ from the modulation unit 58 via the DA unit 62 and the RF unit 50 as a premise. The receiving unit 66 outputs an instruction regarding adjustment of frame timing to the receiving unit 66 of the RNG-RSP.

  The adjustment unit 68 receives an instruction regarding adjustment of frame timing from the reception unit 66. The adjustment unit 68 adjusts the frame timing in accordance with the received instruction. Here, the instruction to adjust the frame timing corresponds to an instruction to adjust the timing when transmitting the packet signal. When the received instruction is an adjustment amount of the frame timing, the adjustment unit 68 adjusts the frame timing according to the adjustment amount. For example, when the adjustment amount instructs to advance the frame timing by “x” sampling points, the adjustment unit 68 advances the frame timing by “x” sampling points according to the instruction. Thereafter, the control unit 64 causes the modulation unit 58 to transmit a packet signal to the DA unit 62 and the IFFT unit 60 while using the adjusted frame timing.

  On the other hand, when the received instruction is to autonomously adjust the frame timing, the adjustment unit 68 outputs the fact to the prediction unit 70. When the prediction unit 70 receives the notification from the adjustment unit 68, the prediction unit 70 predicts the propagation delay amount to the base station device 10. For example, the prediction unit 70 acquires the transmission power at the base station device 10 and the reception power at the RF unit 50, and derives the amount of power loss from the difference between the two. The prediction unit 70 derives the propagation distance from the amount of power loss while using a radio wave propagation law such as a square law. Furthermore, the prediction unit 70 converts the propagation distance into a propagation delay time using the propagation speed of radio waves. Alternatively, the prediction unit 70 may include a GPS receiver (not shown) and measure the location of the terminal device 12. At this time, it is assumed that the packet signal received from the base station apparatus 10 includes information regarding the location of the base station apparatus 10.

  The prediction unit 70 derives the propagation distance from the presence position of the terminal device 12 and the presence position of the base station device 10. In addition, the prediction unit 70 converts the propagation distance into a propagation delay time, as described above. The prediction unit 70 notifies the adjustment unit 68 of the propagation delay time. The adjustment unit 68 receives the propagation delay time from the prediction unit 70, and generates the frame timing while using the propagation delay time. For example, the adjustment unit 68 generates the frame timing by advancing the timing of the packet signal received from the terminal device 12 by the propagation delay time. The control unit 64 causes the modulation unit 58 to transmit the packet signal to the base station apparatus 10 from the modulation unit 58 to the DA unit 62 and the RF unit 50 at the frame timing adjusted by the adjustment unit 68.

  FIG. 4 is a sequence diagram illustrating an outline of timing correction in the communication system 100. The base station apparatus 10 instructs the transmission timing (S200). The transmission timing here corresponds to the transmission timing of RNG-REQ. When a packet signal such as RGN-REQ is received from the terminal device 12, the reception timing is acquired (S202). The terminal device 12 derives an error between the reception timing of the packet signal and the scheduled timing. In response to the error, the base station apparatus 10 transmits to the terminal apparatus 12 an instruction for adjusting the frame timing included in the RGN-RSP.

  The operation of the communication system 100 configured as above will be described. FIG. 5 is a sequence diagram illustrating a timing synchronization procedure in the communication system to be compared with the communication system 100. That is, FIG. 5 corresponds to an operation when frame timing synchronization is not executed according to this embodiment. However, in order to clarify the comparison with the present embodiment, here, the processing between the base station apparatus 10 and the terminal apparatus 12 will be described. The terminal device 12 transmits a packet signal as a transmission signal to the base station device 10 (S10). The transmission signal corresponds to, for example, RGN-REQ. The base station apparatus 10 instructs the terminal apparatus 12 on a transmission timing correction amount (S12). The transmission timing correction amount corresponds to the frame timing adjustment amount included in the RNG-RSP.

  The terminal device 12 corrects the transmission timing according to the instruction (S14). The terminal device 12 transmits a transmission signal to the base station device 10 at the corrected transmission timing (S16). The base station apparatus 10 instructs the terminal apparatus 12 again about the transmission timing correction amount (S18). The terminal device 12 corrects the transmission timing again according to the instruction (S20). The terminal device 12 transmits a transmission signal to the base station device 10 at the corrected transmission timing (S22). The base station apparatus 10 instructs the terminal apparatus 12 again about the transmission timing correction amount (S24). The terminal device 12 corrects the transmission timing again according to the instruction (S26). The terminal device 12 transmits a transmission signal to the base station device 10 at the corrected transmission timing (S28). The base station apparatus 10 notifies the terminal apparatus 12 of synchronization completion (S30).

  FIG. 6 is a sequence diagram illustrating a timing synchronization procedure in the communication system 100. The terminal device 12 transmits a packet signal as a transmission signal to the base station device 10 (S50). The transmission signal corresponds to, for example, RGN-REQ. The base station apparatus 10 instructs the terminal apparatus 12 to autonomously correct transmission timing (S52). The terminal device 12 autonomously corrects the transmission timing (S54). The terminal device 12 transmits a transmission signal to the base station device 10 at the corrected transmission timing (S56). The base station device 10 instructs the terminal device 12 on the correction amount of the transmission timing (S58). The terminal device 12 corrects the transmission timing according to the instruction (S60). The terminal device 12 transmits a transmission signal to the base station device 10 at the corrected transmission timing (S62). The base station device 10 notifies the terminal device 12 of completion of synchronization (S64).

  FIG. 7 is a flowchart showing a timing synchronization procedure in the base station apparatus 10. The reception timing acquisition unit 36 receives a signal from the terminal device 12 from the RF unit 20 via the demodulation unit 26 (S100). If the difference between the reception timing and the scheduled timing is larger than the threshold (Y in S102), the instruction unit 40 instructs the terminal device 12 to autonomously correct the timing (S104). On the other hand, if the difference between the reception timing and the scheduled timing is not greater than the threshold value (N in S102), the instruction unit 40 derives a timing correction amount (S106) and instructs the terminal device 12 of the correction amount. .

  FIG. 8 is a flowchart showing a timing synchronization procedure in the terminal device 12. If the accepting unit 66 does not accept the transmission timing correction amount (N in S150), that is, if it accepts the autonomous timing correction, the adjusting unit 68 derives the transmission timing (S152). The control unit 64 causes the modulation unit 58 to transmit a signal to the DA unit 62 and the RF unit 50 at the derived transmission timing (S154). On the other hand, when the reception unit 66 receives the correction amount of the transmission timing (Y in S150), the adjustment unit 68 corrects the transmission timing according to the correction amount (S156). The control unit 64 causes the modulation unit 58 to transmit a signal to the DA unit 62 and the RF unit 50 at the corrected transmission timing (S158).

  According to the embodiment of the present invention, since the terminal device is instructed to adjust the frame timing autonomously, the number of transmissions of the adjustment amount can be reduced. Further, if the error between the reception timing and the scheduled timing is larger than the threshold value, an instruction to autonomously adjust the frame timing is given, so that the number of transmissions of the adjustment amount can be reduced even if the adjustment amount is small. If the error between the reception timing and the scheduled timing is not larger than the threshold value, the adjustment amount is notified, so that the number of transmissions of the adjustment amount can be reduced while controlling the frame timing of the terminal device.

  Also, since the frame timing is derived based on the propagation delay time, a new frame timing can be derived without being affected by the previous frame timing. Further, since the new frame timing is derived without being influenced by the previous frame timing, the number of transmissions of the adjustment amount can be reduced even if the error with respect to the previous frame timing is large. In addition, since the frame timing is adjusted according to the adjustment amount, an operation according to an instruction from the base station apparatus can be executed.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the structure of the base station apparatus of FIG. It is a figure which shows the structure of the terminal device of FIG. It is a sequence diagram which shows the outline | summary of the timing correction in the communication system of FIG. It is a sequence diagram which shows the timing synchronization procedure in the communication system used as the comparison object of the communication system of FIG. It is a sequence diagram which shows the timing synchronization procedure in the communication system of FIG. It is a flowchart which shows the timing synchronization procedure in the base station apparatus of FIG. It is a flowchart which shows the timing synchronization procedure in the terminal device of FIG.

Explanation of symbols

  10 base station apparatus, 12 terminal apparatus, 20 RF section, 22 AD section, 24 FFT section, 26 demodulation section, 28 modulation section, 30 IFFT section, 32 DA section, 34 control section, 36 reception timing acquisition section, 38 derivation section , 40 indicating unit, 50 RF unit, 52 AD unit, 54 FFT unit, 56 demodulating unit, 58 modulating unit, 60 IFFT unit, 62 DA unit, 64 control unit, 66 receiving unit, 68 adjusting unit, 70 predicting unit, 100 Communications system.

Claims (4)

A receiving unit for receiving a packet signal from the terminal device;
A derivation unit for deriving an error between the timing at which the reception unit receives the packet signal and the timing at which the reception of the packet signal is scheduled;
An instruction unit for instructing the terminal device to adjust timing when transmitting a packet signal based on the error derived in the deriving unit;
The base station apparatus, wherein the instruction unit instructs the terminal apparatus to autonomously adjust timing.   When the error derived by the deriving unit is larger than a threshold value, the instruction unit instructs to adjust the timing autonomously, and the error derived by the deriving unit is not larger than the threshold value The base station apparatus according to claim 1, wherein a timing adjustment amount according to an error is instructed. A receiving unit for receiving an instruction regarding timing when transmitting a packet signal from the base station device;
An adjusting unit that adjusts timing when transmitting a packet signal in accordance with an instruction received in the receiving unit;
A transmission unit that transmits a packet signal to the base station device at a timing adjusted in the adjustment unit,
When the instruction received in the reception unit is an adjustment amount of timing, the adjustment unit adjusts the timing according to the adjustment amount, and the instruction received in the reception unit is to adjust the timing autonomously. A terminal device that adjusts timing by predicting a propagation delay amount to a base station device. Receiving a packet signal from a terminal device;
Deriving an error between the timing at which the packet signal was received and the timing at which the packet signal was scheduled to be received;
Instructing the terminal device to adjust the timing when transmitting a packet signal based on the derived error,
The instructing step instructs the terminal device to autonomously adjust the timing.

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