JP2007028328A - Base station apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base station apparatus for improving communication efficiency. <P>SOLUTION: The base station apparatus 200 comprises a radio unit 210 for receiving preamble transmitted in the predetermined period, a preamble correlation unit 220 for generating a delay profile from the output of the radio unit 210, a maximum path extracting unit 240 for extracting the maximum path power value for each monitoring section in the generated delay profile, a preamble detecting/determining unit 280 for comparing, for a plurality of frames, the maximum value of the maximum path power value in a preamble detecting window formed of a plurality of monitoring sections with a threshold 2 as the reference indicating that a preamble transmitting source exists in the area near the boundary of cells, and a control unit 290 for controlling transmission of the transmission acknowledgment signal to the preamble transmitting source or change in the number of monitoring sections, included in the preamble detecting window on the basis of the result of comparison. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a base station apparatus to which a random access scheme is applied.

  Conventionally, in a random access control method in a CDMA mobile communication system, when a mobile station attempts to place a call, the mobile station transmits a preamble that notifies the base station that a message has occurred prior to the transmission of the message.

When the base station detects reception of the preamble, the base station transmits a transmission control signal (for example, an AICH signal) that permits message transmission to the mobile station that has requested connection. The mobile station that has received this transmission control signal starts message transmission.
JP 2001-204072 A

  However, in the conventional communication system, for example, when the mobile station is near the boundary of a cell covered by the base station, the mobile station may not be able to detect the transmission control signal when the base station transmits the transmission control signal. In such a case, the base station reserves resources to receive a message that is expected to be transmitted from the mobile station, but the message from the mobile station is not transmitted and the base station There is a problem that the utilization efficiency of station resources deteriorates and the communication efficiency of the entire communication system decreases.

  The present invention has been made in view of such a point, and an object thereof is to provide a base station apparatus that improves communication efficiency.

  The base station apparatus of the present invention includes: a receiving unit that receives a preamble transmitted at a predetermined period; a delay profile generating unit that generates a delay profile from an output of the receiving unit; and a maximum path for each predetermined range in the delay profile. Extraction means for extracting the power value of the plurality of frames, comparison means for comparing the maximum value of the maximum path power value in a preamble detection period consisting of a plurality of the predetermined ranges, and a threshold value over a plurality of frames, and Control means for controlling transmission of a transmission permission signal to the preamble transmission source based on the result, or changing the number of the predetermined ranges or the length of the predetermined ranges included in the preamble detection period. Take the configuration.

  ADVANTAGE OF THE INVENTION According to this invention, the base station apparatus which improves communication efficiency can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment, the same components are denoted by the same reference numerals, and the description thereof will be omitted because it is duplicated.

(Embodiment 1)
As illustrated in FIG. 1, the wireless communication system 10 according to the first embodiment includes a mobile station 100 and a base station 200. When the mobile station 100 starts communication with the base station 200, the mobile station 100 first transmits a preamble for a connection request. When the base station 200 detects the preamble, the base station 200 transmits an AICH signal indicating that the connection request is permitted to the mobile station 100. In addition, when the mobile station 100 does not receive the AICH signal even after “predetermined time” from the preamble transmission timing, the mobile station 100 transmits the preamble again. At this time, so-called transmission power ramping may be introduced in which the preamble transmission power is increased stepwise for each retransmission, or retransmission may be performed with the same transmission power.

  1, the base station 200 includes a radio unit 210, a preamble correlation unit 220, a path monitoring unit 230, a maximum path extraction unit 240, a monitoring interval control unit 250, a frame counter 260, a path counter The power storage register 270, the preamble detection determination unit 280, and the control unit 290 are included.

  Radio section 210 receives the preamble from mobile station 100 and outputs it to preamble correlation section 220.

  The preamble correlator 220 obtains a correlation between the preambles, generates a delay profile, and outputs the delay profile to the maximum path extractor 240.

  The maximum path extraction unit 240 receives the delay profile output from the preamble correlation unit 220. Then, the maximum path extraction unit 240 identifies the maximum path (hereinafter referred to as “maximum path”) in which the maximum power peak appears for each fixed “monitoring section” of the delay profile, and extracts the power value of the maximum path. To do. In addition, the maximum path extraction unit 240 identifies the “monitoring section” based on the section switching signal input from the monitoring section control section 250. A plurality of “monitoring sections” form a “preamble detection window” for preamble detection. The “preamble detection window” is a time interval sufficiently shorter than the frame.

  Further, the maximum path extraction unit 240 compares the power value of the maximum path with the input path detection threshold value. If the power value of the maximum path is equal to or greater than the path detection threshold value, the maximum path extraction unit 240 extracts the maximum The power value of the path is output to the path information storage register 270.

  Referring to FIG. 2 in detail, in this figure, the monitoring sections with monitoring section numbers 1 to 8 form a preamble detection window, and the length of the preamble detection window composed of these eight monitoring sections is as follows. It becomes the reference length. Then, the maximum path power value exceeding the threshold Th10 is detected in the monitoring section numbers 4 and 7.

  The monitoring section control unit 250 outputs a section switching signal to the maximum path extraction unit 240 so that a predetermined number of monitoring sections are included in the reference length of the preamble detection window in the initial stage, and within the same preamble detection window. The section number as the monitoring section identification information is output to the path power storage register 270.

  In addition, the monitoring section control unit 250 controls the length of the preamble detection window by increasing or decreasing the number of monitoring sections in accordance with the preamble detection window change signal from the control unit 290.

  The frame counter 260 receives a frame signal and increases the counter value by one in response to this input. The counter value is output to the path power storage register 270 as a frame number.

  In this way, the path power storage register 270 inputs the power value of the maximum path for each monitoring section, the section number of the monitoring section, and the frame number, and temporarily stores them in association with each other in order. Output to 280.

  Preamble detection determination section 280 first inputs threshold value 1 and threshold value 2. Preamble detection determination section 280 receives the maximum path power value for each identical frame number input from path power storage register 270 and compares it with threshold values 1 and 2. Note that the threshold value 1 is larger than the threshold value 2. The threshold value 1 is used as a reference for determining that the mobile station 100 exists at a short distance from the base station 200. The threshold value 2 is used as a reference for determining that the mobile station 100 exists near the boundary of the cell covered by the base station 200.

  As a result of the comparison, when a maximum path with a threshold value of 1 or more appears, the preamble detection determination unit 280 immediately determines that a preamble has been detected, and outputs result information to that effect to the control unit 290.

  If the maximum path power value equal to or greater than the threshold value 2 does not appear for a predetermined frame as a result of the comparison, the preamble detection determination unit 280 uses the extended information indicating that the preamble detection window is extended as result information to the control unit To 290.

  Then, after outputting the extension information to the control unit 290, the preamble detection determination unit 280 detects the maximum path power value greater than or equal to the threshold 2 in the monitoring interval included in the reference length of the preamble detection window. The reduction information for reducing the detection window is output to the control unit 290.

  Furthermore, after the extended information is output to the control unit 290, when a maximum path power value greater than or equal to the threshold value 2 is detected in the monitoring section corresponding to the portion extended from the reference length of the preamble detection window, and continuously When the maximum path power value greater than or equal to the threshold value 2 is not detected, the preamble detection determination unit 280 does not output any information to the control unit 290.

  In addition, as a result of the comparison, when the maximum path power value that is greater than or equal to the threshold value 2 and less than the threshold value 1 appears continuously over several frames (however, continuous monitoring included in the reference length of the preamble detection window) If it appears only in a section), it is determined that the preamble has been detected, and result information to that effect is output to the control unit 290.

  Here, the movement of the preamble detection determination unit 280 will be specifically described with reference to FIG.

  As shown in FIG. 3 (a), when the maximum path power value above the threshold value 2 cannot be detected within a certain preamble detection window and has not been detected for N frames, FIG. As shown in (b), an extension signal is output so that the number of monitoring sections is increased and the preamble detection window is extended.

  When the maximum path power value greater than or equal to threshold 2 is detected within the preamble detection window in the subsequent frame, the monitoring interval in which the maximum path power value greater than or equal to threshold 2 is detected is the reference length of the preamble detection window No information is output to the control unit 290 particularly when it corresponds to the range expanded from (see FIG. 3B).

  On the other hand, when a maximum path power value greater than or equal to threshold 2 is detected within the preamble detection window in the subsequent frame, the monitoring interval in which the maximum path power value greater than or equal to threshold 2 is detected is the preamble detection window. When it corresponds to the range of the reference length (FIG. 3C), it is determined that the preamble has been detected only when the detection is continuous over N frames, and the result information indicating that is included in the control unit. To 290. When the detection has not yet continued over N frames, it is not yet determined that the preamble has been detected, but it is determined that the mobile station 100 tends to approach the base station 200 and the preamble detection window. Is output to the control unit 290.

  In this way, while expanding the preamble detection window so that the preamble of the mobile station 100 located near the cell boundary can be tracked with the threshold 2 as a reference, within the monitoring interval included in the reference length of the preamble detection window When the maximum path power value equal to or greater than the threshold value 2 is detected, the mobile station 100 may transmit the AICH to the mobile station 100 after determining that the mobile station 100 tends to approach the base station 200 from near the cell boundary. it can. As a result, while the base station 200 secures resources for the mobile station 100 that transmitted the AICH, the mobile station 100 cannot detect the AICH and the message is not sent. It is possible to prevent the deterioration of the utilization efficiency and consequently the communication efficiency of the entire communication system.

  Upon receiving the result information indicating that the preamble has been detected from the preamble detection determination unit 280, the control unit 290 transmits the AICH to the mobile station 100 via the radio unit 210.

  When receiving an expansion signal or a reduction signal from the print detection determination unit 280, the control unit 290 outputs a preamble detection window change signal corresponding to the signal to the monitoring section control unit 250.

  As described above, according to the first embodiment, the radio unit 210 that receives the preamble transmitted to the base station 200 at a predetermined period, the preamble correlation unit 220 that creates the delay profile from the output of the radio unit 210, and the creation A maximum path extraction unit 240 that extracts a power value of a maximum path for each monitoring section in the delay profile, a maximum value of a maximum path power value in a preamble detection window composed of a plurality of monitoring sections, and a transmission source of the preamble is a cell A preamble detection determination unit 280 that compares the threshold value 2 serving as a reference for existence near the boundary over a plurality of frames, and transmission of a transmission permission signal to the transmission source of the preamble based on the comparison result, or And a control unit 290 for controlling the change in the number of monitoring sections included in the preamble detection window. .

  In this way, by tracking the preamble by expanding the preamble detection window based on the threshold value 2, it is possible to track the movement status of the source of the preamble located near the cell boundary. Since the transmission of the transmission permission signal can be controlled according to the movement status, the resource utilization efficiency of the base station associated with the fact that a message corresponding to the transmission permission signal is not sent while securing resources to the transmission source It is possible to prevent the deterioration of the communication efficiency and the communication efficiency of the entire communication system.

  The control unit 290 extends the preamble detection window by increasing the number of monitoring sections when the maximum value is less than the threshold value 2 over a plurality of frames, and the monitoring section within the reference length of the preamble detection window. When the maximum value equal to or greater than threshold value 2 appears over a plurality of frames in FIG. 4, the transmission permission signal is controlled to be transmitted, and threshold value 2 is detected in the monitoring interval corresponding to the extended portion from the reference length of the preamble detection window. When the above maximum value appears, transmission of the transmission permission signal is controlled when the maximum value greater than or equal to the threshold value 2 subsequently appears over a plurality of frames.

  In this way, when the maximum value greater than or equal to the threshold value 2 appears in the monitoring section corresponding to the extended portion from the reference length of the preamble detection window, the maximum value greater than or equal to the threshold value 2 is then displayed in a plurality of frames. When it appears, it can be determined that the transmission source tends to be closer to the base station, and transmission of the transmission permission signal is controlled when it can be determined, so resources are secured for the transmission source. However, it is possible to prevent the base station resource utilization efficiency from deteriorating due to the fact that a message corresponding to the transmission permission signal is not sent, and hence the communication efficiency of the entire communication system.

(Embodiment 2)
In the first embodiment, the length of the preamble detection window is adjusted by increasing or decreasing the number of “monitoring sections” when a predetermined condition is satisfied. On the other hand, in the second embodiment, the number of “monitoring sections” included in the preamble detection window is fixed, and the sampling rate in the “monitoring section” is changed to change the length of the “monitoring section”, thereby changing the preamble detection window. Is adjusted (see FIG. 4). Incidentally, the monitoring section 3 is extended in FIG.

  As shown in FIG. 5, the base station 300 of Embodiment 2 includes a preamble correlation unit 310, a maximum path extraction unit 320, and a monitoring section control unit 330.

  The monitoring section control unit 330 controls the length of the preamble detection window by expanding or reducing the length of a certain monitoring section in accordance with the preamble detection window change signal from the control unit 290.

  In addition, the monitoring section control unit 330 outputs a sampling rate increase signal or a sampling rate decrease signal as a sampling rate change signal to the preamble correlation unit 310 to increase or decrease the sampling rate in the monitoring section to be expanded or contracted.

  The preamble correlator 310 generates a delay profile in which the sampling rate is adjusted according to the sampling rate increase signal or the sampling rate decrease signal from the monitoring section control unit 330. In this way, the maximum path extraction unit 320 can receive a delay profile whose length is adjusted for each monitoring section.

  As described above, according to the second embodiment, the radio unit 210 that receives the preamble transmitted to the base station 300 at a predetermined period, the preamble correlation unit 310 that creates the delay profile from the output of the radio unit 210, and the creation A maximum path extraction unit 320 that extracts a power value of a maximum path for each monitoring section in the delayed profile, a maximum value of a maximum path power value in a preamble detection window including a plurality of monitoring sections, and a source of the preamble is a cell source A preamble detection determination unit 280 that compares the threshold value 2 serving as a reference for existence near the boundary over a plurality of frames, and transmission of a transmission permission signal to the transmission source of the preamble based on the comparison result, or A control unit 290 that controls a change in the length of the monitoring section included in the preamble detection window. .

  In this way, by tracking the preamble by expanding the preamble detection window based on the threshold value 2, it is possible to track the movement status of the source of the preamble located near the cell boundary. Since the transmission of the transmission permission signal can be controlled according to the movement status, the resource utilization efficiency of the base station associated with the fact that a message corresponding to the transmission permission signal is not sent while securing resources to the transmission source It is possible to prevent the deterioration of the communication efficiency and the communication efficiency of the entire communication system.

  The control unit 290 expands the preamble detection window by increasing the length of the monitoring section when the maximum value is less than the threshold value 2 over a plurality of frames, and monitors within the reference length of the preamble detection window. When the maximum value greater than or equal to threshold value 2 appears over a plurality of frames in a section, transmission of the transmission permission signal is controlled, and a threshold value is detected in a monitoring section corresponding to an extended portion from a reference length of a preamble detection window. When the maximum value of 2 or more appears, transmission of the transmission permission signal is controlled when the maximum value of threshold 2 or more appears over a plurality of frames.

  In this way, when the maximum value greater than or equal to the threshold value 2 appears in the monitoring section corresponding to the extended portion from the reference length of the preamble detection window, the maximum value greater than or equal to the threshold value 2 is then displayed in a plurality of frames. When it appears, it can be determined that the transmission source tends to be closer to the base station, and transmission of the transmission permission signal is controlled when it can be determined, so resources are secured for the transmission source. However, it is possible to prevent the base station resource utilization efficiency from deteriorating due to the fact that a message corresponding to the transmission permission signal is not sent, and hence the communication efficiency of the entire communication system.

  The base station apparatus of the present invention is useful for improving communication efficiency.

1 is an overall configuration diagram of a radio communication system according to Embodiment 1 of the present invention. The figure for demonstrating operation | movement of the largest path extraction part of FIG. The figure which uses for description of operation | movement of the preamble detection determination part of FIG. The figure for demonstrating operation | movement of the base station which concerns on Embodiment 2. FIG. Block diagram showing the configuration of a base station according to Embodiment 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Radio communication system 100 Mobile station 200, 300 Base station 210 Radio part 220, 310 Preamble correlation part 230 Path monitoring part 240, 320 Maximum path extraction part 250, 330 Monitoring section control part 260 Frame counter 270 Path power storage register 280 Preamble detection Determination unit 290 control unit

Claims (2)

Receiving means for receiving a preamble transmitted at a predetermined period;
Delay profile creating means for creating a delay profile from the output of the receiving means;
Extraction means for extracting the power value of the maximum path for each predetermined range in the delay profile;
A comparing means for comparing the maximum value of the maximum path power value in a preamble detection period consisting of a plurality of the predetermined ranges and a threshold value over a plurality of frames;
Based on the result of the comparison, control means for controlling transmission of a transmission permission signal to the transmission source of the preamble, or changing the number of the predetermined range or the length of the predetermined range included in the preamble detection period;
A base station apparatus comprising: The control means extends the preamble detection period by increasing the number of the predetermined range or extending the predetermined range when the maximum value is less than the threshold over a plurality of frames,
If the maximum value equal to or greater than the threshold value appears over a plurality of frames in the predetermined range within the reference length of the preamble detection period, control transmission of the transmission permission signal,
When the maximum value equal to or greater than the threshold appears in the predetermined range corresponding to an extension from the reference length of the preamble detection period, the maximum value equal to or greater than the threshold appears thereafter over a plurality of frames. 2. The base station apparatus according to claim 1, wherein transmission of the transmission permission signal is controlled when the transmission permission signal is received.

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