JP5482751B2 - Optimal radio communication system, transmitter, and receiver using variable radio frame control - Google Patents

Description

  The present invention relates to an optimal wireless communication system, a transmitting apparatus, and a receiving apparatus using wireless frame variable control.

  FIG. 1 is a diagram showing a radio format standardized by 3GPP (Third Generation Partnership Project) as an international standard for a third-generation high-speed mobile communication system.

  In particular, FIG. 1 shows only the nth frame. Therefore, the (n−1) th frame and the (n + 1) th frame not shown are consecutive before and after the nth frame.

  In FIG. 1, a plurality of continuous or non-continuous frequency regions are assigned in the vertical direction, that is, in the frequency axis direction. Since the frequency domain is frequency-divided so that the phases are orthogonal to each other, no interference occurs.

  A plurality of OFDM (Orthogonal Frequency Division Multiplexing) symbols are arranged in the horizontal direction, that is, in the time direction, to form one frame.

  Here, one OFDM (Orthogonal Frequency Division Multiplexing) symbol corresponds to 1 TTI (Transmission Time Interval).

  Further, at the head of each frame in the time axis direction, a common pilot channel 1 and a control channel 2 are arranged as a set in the frequency axis direction. These are set for each user or for different channels.

  The common pilot channel 1 indicates a subframe delimiter, and gives timing for calculating the SNR (signal-to-noise ratio) and the reception level by looking at the pilot for all users. The control channel 2 has demodulation information corresponding to the signal data modulation method.

  Thus, the conventional configuration uses a fixed frame format having a common pilot channel 1 and a control channel 2 for each frame.

  When such a fixed frame format is used, even in a situation where the line speed can be increased depending on the condition of the line between the transmission side apparatus (base station) and the reception side apparatus (mobile terminal) in the mobile communication system. It was difficult to cope with.

  In view of this point, the present applicant has proposed to improve the channel estimation accuracy and improve the throughput of the entire base station by using an appropriate frame pattern in advance (Patent Document 1). .

Japanese Patent Application No. 2005-345325

  However, the invention presented in Patent Document 1 controls the number of pilot channel dispersions between frames. For example, the number of pilot channel symbols is increased or decreased for terminals having good reception quality, for example, terminals moving at low speed, or the number of pilot channel symbols distributed between frames is decreased to prevent deterioration of the throughput of the base station. .

  Accordingly, an object of the present invention is to provide an optimal radio communication system, transmission apparatus, and reception apparatus based on radio frame variable control that can reduce not only pilot channel symbols but also control channel symbols more flexibly. There is.

  A first aspect of the present invention that achieves the above object is to transmit a data frame in which a plurality of continuous or non-consecutive frequency regions are assigned to one transfer time interval and a frame is composed of a predetermined number of transfer time intervals. A wireless communication system having a transmitting side device and a receiving side device that receives a data frame from the transmitting side device, wherein the transmitting side device places a common pilot channel and a control channel at the head of the frame to create a data frame To the receiving device, the receiving device measures the reception quality of the data frame, determines a frame type based on the measured reception quality, and sends the determined frame type to the transmitting device. The transmitting side device notifies the subsequent frame data in a frame format corresponding to the notified frame type. Characterized in that the send.

  Further, as a second aspect, a transmission side device that transmits a data frame in which a plurality of continuous or non-consecutive frequency regions are allocated to one transfer time interval and a frame is configured in a predetermined number of transfer time intervals; A wireless communication system having a reception side device for receiving a data frame from a transmission side device, wherein the transmission side device transmits a data frame to the reception side device by placing a common pilot channel and a control channel at the head of the frame. The reception side apparatus measures the reception quality of the frame and feeds back the measured reception quality to the transmission side apparatus, and the transmission side apparatus determines a frame type based on the fed back reception quality. Then, the subsequent frame data is sent to the receiving side device in the frame format corresponding to the determined frame type. It is characterized in.

  On both sides, the frame type determined based on the reception quality is a frame format that does not include at least the control channel among the common pilot channel and the control channel, and the reception quality is set in advance. It includes the number of frames that can maintain the characteristics determined by comparison with the threshold value.

  Due to the above-described feature of the present invention, the reception quality can be reduced not only for the pilot channel symbol but also for the control channel symbol more flexibly with respect to the device receiving the name of the item. Therefore, the data symbols can be replaced by data corresponding to the decrease in the number of channel symbols, so that high-speed data transmission can be performed more flexibly.

It is a figure which shows the radio | wireless format standardized by 3GPP as an international standard of a 3rd generation high-speed mobile communication system. 1 is a block diagram of a schematic configuration of a transmission-side apparatus according to a first embodiment to which an optimum wireless communication method by wireless frame variable control according to the present invention is applied. FIG. FIG. 3 is a block diagram of a schematic configuration of a reception-side device corresponding to the transmission-side device of FIG. 2. It is a flowchart which shows the process sequence between the transmission side apparatus in 1st Example, and a receiver. It is a figure explaining the example (the 1) of the frame type according to this invention. It is a figure explaining the example (the 2) of the frame type according to this invention. It is a figure which shows the flow of frame type determination. It is a figure which shows an example of the notification frame sent to the transmission side apparatus from the reception side apparatus. It is an example of the frame format sent from the transmission side apparatus to the reception side apparatus. It is a block diagram of a configuration example of a transmission side device in the second embodiment. It is an example block diagram of the structure of the receiving side apparatus in 2nd Example. It is a flowchart which shows the process sequence between the transmission side apparatus in a 2nd Example, and a receiver.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiments are for understanding the present invention, and the application of the present invention is not limited to these embodiments.

  FIG. 2 is a block diagram of a schematic configuration of a transmission-side apparatus according to the first embodiment to which an optimum radio communication method by radio frame variable control according to the present invention is applied. FIG. 3 is a schematic block diagram of a receiving apparatus corresponding to the transmitting apparatus in FIG.

  And as one aspect, the transmitting side apparatus of FIG. 2 is a base station apparatus, and the receiving side apparatus of FIG. 3 corresponds to a mobile terminal.

  FIG. 4 is a flowchart showing a processing sequence between the transmission side apparatus and the reception apparatus in the first embodiment.

  In FIG. 4, a frame signal is transmitted with the frame type A from the transmission side apparatus 100 of FIG. 2 to the reception side apparatus 200 (step S1).

  Here, the frame type A is the conventional frame format shown in FIG. 1, and has a common pilot channel 1 and a control channel 2 at the head of the frame.

  In the transmission side apparatus 100 shown in FIG. 2, the data generation unit 101 generates transmission data, and the pilot generation unit 102 generates a pilot signal.

  Next, transmission data and a pilot signal are input by the multiplexing unit 103 and time division multiplexed. The time-division multiplexed serial signal is serial / parallel converted by the S / P converter 104. Next, the parallel signal subjected to serial-parallel conversion is converted into a time-series signal by an inverse discrete Fourier transform (IDFT) unit 105 and further converted into a serial signal by a P / S conversion unit 106. The serial signal is modulated by the transmission unit 107 by an appropriate modulation method, power amplified, and transmitted from the antenna 108 as a transmission signal Tx.

  Further, in FIG. 2, reception processing is performed on the reception signal Rx received by the antenna 109. A demodulation / decoding unit 111 extracts a control channel from the signal received by the receiving unit 110. Since this control channel includes reception level information and the like on the receiving side, multiplexing processing by the multiplexing unit 103, that is, frame type setting is performed according to the present invention.

  The configuration of the receiving side device 200 in FIG. 3 has a processing function substantially opposite to that of the transmitting side device in FIG.

  The reception unit 210, the S / P conversion unit 202, the discrete Fourier transform (DFT) unit 203, the P / S conversion unit 204, the demodulation unit 205, and the decoding unit 206 are respectively connected to the transmission unit 107 of the transmission side apparatus shown in FIG. , A P / S conversion unit 106, an inverse discrete Fourier transform (IDFT) unit 105, an S / P conversion unit 104, a multiplexing unit 103, and a function process opposite to the processing function corresponding to the data generation unit 101 is performed. Therefore, further explanation of these parts is omitted.

  The configuration provided according to the present invention includes a frame determination unit that determines a frame type to be described later based on an output of a reception quality information generation unit 207 that generates reception quality information with reference to the signal level decoded by the decoding unit 206. 208. The frame information determined by the frame determination unit 208 is transmitted from the transmission antenna 210 toward the transmission side device 100 by the transmission unit 209.

  Here, the frame type is described as follows according to the present invention.

  FIG. 5 and FIG. 6 are diagrams for explaining examples (part 1 and part 2) of the frame type according to the present invention.

  In FIG. 5, frame n is the frame type A shown in FIG. 1, and has a common pilot channel 1 and a control channel 2 at the head of the frame. User data is placed in other frame areas.

  On the other hand, in FIG. 5, the frame n + 1 does not have the control channel 2, and this area is used as an area for further carrying user data. This type of frame format is hereinafter referred to as frame type B. Therefore, the frame type B carries a larger amount of user data than the frame type A for the free control channel region.

  In FIG. 5, the frame type A further includes one frame, and the subsequent frame is followed by the frame type B.

  In the frame format shown in FIG. 6, in the frame format subsequent to the frame type A, the area of the common pilot channel 1 is filled with user data, and only the control channel 2 and user data are carried. This is hereinafter referred to as frame type C.

  Further, only the user data is placed on the frame format following the frame type C, and neither the common pilot channel 1 nor the control channel 2 is placed. This is hereinafter referred to as frame type D.

  The frame types shown in FIGS. 5 and 6 are set in accordance with the control channel from the receiving side apparatus 200 in the transmitting side apparatus 100 shown in FIG.

  That is, in FIG. 4, when the frame type A frame format is transmitted from the transmission side apparatus 100 to the reception side apparatus 200 (step S1), the reception side apparatus 200 uses the frame type used according to the processing flow shown in FIG. To decide.

  Here, the above frame type can be applied according to the reception quality.

  A frame type and the number of frames are determined by the frame determination unit 208 according to the reception quality of the reception data received by the reception-side apparatus 200, and the corresponding frame information is output.

  FIG. 7 shows a flow for determining the frame type. In FIG. 7, a signal of frame type A is transmitted from the transmission side apparatus 100 and received (step S10).

  The reception quality information generation unit 207 measures reception quality based on the received frame type A signal (step S11).

  That is, when the frame type is A (normal frame), the reception quality is measured by averaging several frames (step S11).

  Two types of reception quality threshold values (first threshold value, second threshold value) are set in the frame determination unit 208 in advance, and the measured reception quality is compared with each threshold value (steps S12 and S13) to determine the frame type. To do.

  For example, if the propagation environment is not good when the moving speed of the receiving side apparatus 200 (mobile terminal) is fast, the reception quality is naturally deteriorated (below the first threshold value: Step S12, No), and communication with the frame type A Become.

  When the moving speed of the receiving-side apparatus 200 becomes slow and the reception quality is improved (from the first threshold value to the second threshold value: Step S13, No), the frame types B and C are selected (Step S14). ).

  Further, when the reception quality is particularly improved (eg, the second threshold or higher: step S13, Yes), for example, when the mobile terminal is stationary, communication with the frame type D is performed.

  Here, as an example, frame types A, B, C, and D are defined as follows.

Frame type A (Fig. 5): Normal frame (pilot CH + control CH + data CH)
Frame type B (Fig. 5): Frame without control CH (pilot CH + data CH)
Frame type C (Fig. 6): No pilot CH frame (control CH + data CH)
Frame type D (FIG. 6): Frame with only data CH.

  In frame types B, C, and D, each frame does not have a control CH or pilot CH. Therefore, the data CH is demodulated based on the last received and stored control CH or pilot CH. Processing and reception quality measurement processing.

  In the above frame type, the transmission capacity (throughput) for one user (assuming 2 × 7 = 14 symbols in one frame) is compared. When frame type D is used, about 1.. The transmission capacity is 27 times.

  As described above, when the frame type is determined by the frame determination unit 208, the frame information is notified from the reception side device 200 to the transmission side device 100 by the notification frame shown in FIG. 8 as an example (step S2: FIG. 4). .

  That is, in the frame information shown in FIG. 8, the contents added to the control channel are the frame type I and the number of frames II.

  Four types (frame types A to D) are assigned to information indicating the frame type I in 2 bits. 10 bits are assigned to the information indicating the number of frames II, and the number of continuous transmissions of the determined frame type is notified. When the number of frames is 0, the value of frame type I is invalid.

  Here, the number of frames II is the number of frames that can maintain the characteristics determined by comparing the reception quality with a preset reception quality threshold. As one method, the number of frames that can maintain the characteristics in combination with the frame type I can be set in advance corresponding to the reception quality threshold.

  Next, the transmission side device 100 recognizes the frame information notified from the reception side device 200 by the control channel demodulation / decoding unit 111 and controls the transmission frame by the data generation unit 101 and the multiplexing unit 103 so as to correspond to this. (Step S3: FIG. 4).

  FIG. 9 shows an example of a frame format transmitted from the transmission side apparatus 100 to the reception side apparatus 200 according to the above embodiment.

  According to this frame format, the transmission side device 100 (base station) uses different frame types according to the state of each user.

  User 1: Transmission is performed with frame type A from frame n.

  User 2: Frame type B is transmitted from frame n + 1.

  User 3: Frame type D is transmitted from frame n + 2.

  As described above, the frame type can be individually set for each user.

  In the embodiment described above, the reception quality is measured by the receiving side device (mobile terminal) 200 and the frame type and the number of frames are requested from the transmitting side device (base station) 100. Based on the received reception quality information, the frame type and the number of frames can be determined on the base station side.

  Furthermore, when the amount of transmission data from the base station side is small, a pilot CH is inserted and transmitted instead of padding the data CH. On the mobile terminal side, the pilot CH received at the end of each frame is adopted for channel estimation measurement.

  Communication suitable for each mobile terminal device can be performed by preparing a plurality of frame types according to the amount of transmission data.

  FIGS. 10 and 11 show a case where the frame type and the number of frames are determined by the transmission side apparatus (base station) 100 from the reception quality information fed back from the reception side apparatus (mobile terminal) 200 as the second embodiment. FIG. 3 is a block diagram illustrating a configuration example of a transmission side device 100 and a reception side device 200. FIG. 12 is a flowchart showing a processing sequence between the transmission side apparatus and the reception apparatus in the second embodiment.

  The difference from the first embodiment is that the frame determination unit 112 is in the transmission side apparatus 100 (FIG. 10). Therefore, the receiving side apparatus 200 does not have such a frame determination unit (FIG. 11).

  In the processing sequence shown in FIG. 12, a normal frame type A frame format is transmitted from the transmission side apparatus 100 (step S20). Therefore, the reception quality information generation unit 207 of the reception-side apparatus 200 generates information indicating the quality at the time of reception of the frame type A frame format.

  For example, a signal-to-noise ratio (SNR) is obtained based on the channel estimation value. As another example, the reception quality information generation unit 207 may obtain a bit error rate (BER). The obtained reception quality information is fed back to the transmission side apparatus 100 (step S21).

  In the transmission-side apparatus 100, the received feedback information is passed to the frame determination unit 112. The frame determination unit 112 determines the frame type and the number of frames necessary for the next data reception based on the feedback information of the reception quality, adds them to the control channel information in the transmission frame, and sends them to the reception side device 200. Notification is made (step S23). As a result, the receiving-side apparatus 200 can subsequently perform data demodulation processing according to the control channel information.

  As described above, according to the present invention, by making the frame type and the number of frames variable for each user, optimal transmission is possible according to the propagation state of the user.

(Appendix 1)
A transmission side device that transmits a data frame in which a plurality of continuous or non-consecutive frequency regions are allocated to one transfer time interval and a frame is configured in a predetermined number of transfer time intervals, and a data frame from the transmission side device is A wireless communication system having a receiving side device for receiving,
The transmitting side device transmits a data frame to the receiving side device with the common pilot channel and the control channel placed at the beginning of the frame,
The receiving side device measures the reception quality of the data frame, determines a frame type based on the measured reception quality, and notifies the transmitting side device of the determined frame type;
The wireless communication system, wherein the transmitting device transmits subsequent frame data to the receiving device in a frame format corresponding to the notified frame type.

(Appendix 2)
A transmission side device that transmits a data frame in which a plurality of continuous or non-consecutive frequency regions are allocated to one transfer time interval and a frame is configured in a predetermined number of transfer time intervals, and a data frame from the transmission side device is A wireless communication system having a receiving side device for receiving,
The transmitting side device transmits a data frame to the receiving side device with the common pilot channel and the control channel placed at the beginning of the frame,
The receiving side device measures the reception quality of the frame and feeds back the measured reception quality to the transmitting side device;
The transmission side device determines a frame type based on the feedback quality received and sends subsequent frame data to the reception side device in a frame format corresponding to the determined frame type. system.

(Appendix 3)
In Appendix 1 or 2,
The frame type determined based on the reception quality is a frame format that does not include at least the control channel among the common pilot channel and the control channel, and the reception quality is compared with a preset reception quality threshold value. A wireless communication system comprising a number of frames capable of maintaining a determined characteristic.

(Appendix 4)
In Appendix 3,
A wireless communication system, wherein the frame format is configured so that transmission data is placed in an empty area of the control channel in the frame format not including at least the control channel.

(Appendix 5)
In Appendix 1 or 2, each of a plurality of continuous or non-consecutive frequency regions is assigned to a plurality of users,
A wireless communication system, wherein different frame types are determined corresponding to reception quality in each of the receiving side apparatuses corresponding to the plurality of users.

(Appendix 6)
In Appendix 1 or 2,
When the transmission data amount of the transmission side apparatus is small, the number of data channel symbols in the frame format is decreased, and the number of common pilot channel symbols is increased corresponding to the decrease in the number of data channel symbols. Wireless communication system.

(Appendix 7)
A transmission side device that transmits a data frame in which a plurality of continuous or non-consecutive frequency regions are allocated to one transfer time interval and a frame is configured in a predetermined number of transfer time intervals, and a data frame from the transmission side device is A receiving side device in a wireless communication system having a receiving side device for receiving,
The common pilot channel and control channel are placed at the beginning of the frame and the data frame is received by the receiving device.
Measuring the received quality of the received data frame;
Comparing the measured reception quality with a preset reception quality threshold, determine a frame format that does not include at least the control channel and the number of frames that can maintain the characteristics;
The information on the determined frame format and the number of frames is fed back to the transmission side device.

(Appendix 8)
A transmission side device that transmits a data frame in which a plurality of continuous or non-consecutive frequency regions are allocated to one transfer time interval and a frame is configured in a predetermined number of transfer time intervals, and a data frame from the transmission side device is A transmitting side device in a wireless communication system having a receiving side device for receiving,
Receiving the reception quality information in the reception side device from the reception side device with respect to the data frame transmitted to the reception side device with the common pilot channel and the control channel placed at the head of the frame;
Based on the received reception quality information, a frame format not including at least the control channel and the number of frames capable of maintaining the characteristics are determined by comparing the reception quality on the receiver side with a preset reception quality threshold. And
The transmitting apparatus, wherein the determined number of data frames is transmitted to the receiving apparatus in the determined frame format.

(Appendix 9)
A transmission / reception method in a wireless communication system, comprising:
A data frame is transmitted from the transmission side device by placing a common pilot channel and a control channel at the beginning of the frame and received by the reception side device.
The reception quality of the data frame is measured by the receiving device,
Determining a frame type based on the measured reception quality;
A wireless communication system, wherein the subsequent frame data is transmitted from the transmitting device to the receiving device in a frame format corresponding to the notified frame type.

100 Transmitting device (base station)
200 Receiver device (mobile terminal)
101 Data Generation Unit 102 Pilot Generation Unit 103 Multiplexing Unit 104, 202 S / P Conversion Unit 105 IDFT Unit 106, 204 P / S Conversion Unit 107, 209 Transmission Unit 110, 210 Reception Unit 111 Control Channel Demodulation / Decoding Units 108, 109 , 210 Antenna 203 DFT unit 205 Demodulation unit 206 Decoding unit 207 Reception quality generation unit 208 Frame determination unit 211 Channel estimation unit

Claims (5)

A transmission device in which a plurality of continuous or non-consecutive frequency regions are assigned to one time interval and data is transmitted using a radio frame configured in the time interval, and transmission is performed using the radio frame from the transmission device A wireless communication system including a receiving device that receives received data,
The transmitting apparatus transmits to the receiving apparatus a radio frame in which a pilot, which is a known signal used for reception quality measurement in the receiving apparatus, and a control signal used for controlling demodulation processing in the receiving apparatus are arranged at the head of the radio frame. ,
The reception apparatus transmits reception quality information, which is information related to reception quality measured using the pilot, to the transmission apparatus,
The transmitter is
Controlling control information for the receiving device that has transmitted the reception quality information;
A wireless communication system, wherein a data transmission process is executed using a wireless frame format that does not include control information for a receiving apparatus that has transmitted the reception quality information. A transmission device in which a plurality of continuous or non-consecutive frequency regions are assigned to one time interval and data is transmitted using a radio frame configured in the time interval, and transmission is performed using the radio frame from the transmission device A wireless communication system including a receiving device that receives received data,
The transmitting apparatus transmits to the receiving apparatus a radio frame in which a pilot, which is a known signal used for reception quality measurement in the receiving apparatus, and a control signal used for controlling demodulation processing in the receiving apparatus are arranged at the head of the radio frame. ,
A receiving apparatus that has received the radio frame in which the pilot and the control signal are arranged receives a signal requesting execution of data transmission processing using a radio frame format that does not include control information for the receiving apparatus. To
The receiving device that has transmitted the request signal performs processing for receiving data from the transmitting device using the radio frame format.
A wireless communication system. A transmission device in which a plurality of continuous or non-consecutive frequency regions are assigned to one time interval and data is transmitted using a radio frame configured in the time interval, and transmission is performed using the radio frame from the transmission device A transmission device in a wireless communication system in which there is a reception device that receives received data,
A radio frame in which a pilot, which is a known signal used for measurement of reception quality in a reception device, and a control signal used for control of demodulation processing in the reception device is transmitted at the beginning of the radio frame;
Receiving reception quality information that is information on reception quality measured using the pilot;
Controlling control information for the receiving device that has transmitted the reception quality information;
A transmission apparatus that performs data transmission processing using a radio frame format that does not include control information for the reception apparatus that has transmitted the reception quality information. A transmission device in which a plurality of continuous or non-consecutive frequency regions are assigned to one time interval and data is transmitted using a radio frame configured in the time interval, and transmission is performed using the radio frame from the transmission device A receiving device in a wireless communication system including a receiving device that receives received data,
Receiving a radio frame in which a pilot, which is a known signal used for measurement of reception quality in a receiving device, and a control signal used for controlling demodulation processing in the receiving device are arranged at the head of the radio frame;
In response to receiving the radio frame in which the pilot and the control signal are arranged, a signal requesting execution of data transmission processing using a radio frame format not including a control signal for the receiving device is transmitted. To the device,
In response to transmitting the request signal, data is received from the transmitter using the radio frame format.
A receiving apparatus. In a wireless communication system that performs communication using a region defined by time and a plurality of continuous or non-consecutive frequencies,
A transmission apparatus including a transmission unit that sets a region 1 for transmitting only data and pilot, and a region 2 for transmitting data, pilot, and control signals, and performs transmission using the region;
With a receiving device including a receiving unit that receives data transmitted in the region 1 using a control signal transmitted in the region 2,
A wireless communication system characterized by being configured.

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