JP4624832B2 - Moving speed estimation circuit and moving speed estimation method - Google Patents

Description

  The present invention relates to a moving speed estimation circuit and method, and more particularly, to a moving speed estimation circuit and method effective when applied to a code division multiple access (CDMA) system.

      As a channel multiplexing method in a mobile communication system, a time division multiple access (TDMA) method, a frequency division multiple access (FDMA) method, or the like has been used. A direct sequence code division multiple access (DS-CDMA) system, which is a system with higher utilization efficiency, has been commercialized as a system capable of realizing a large communication capacity.

  The DS-CDMA system is a kind of spread spectrum communication. In this method, the transmission side uses the same frequency for a plurality of channels and multiplies the data signal by an independent wideband spreading code for each channel, thereby expanding the spectrum of the data signal and transmitting the same spread on the receiving side. Multiply the code to restore the data signal for each channel. Multiplication of the spreading code on the receiving side is called despreading. When this DS-CDMA system is applied to mobile communication, a searcher function, a transmission power control function, an absolute synchronous detection function, and the like are indispensable.

  The searcher function is a function that detects the despread code timing, which is the timing for detecting the transmission path and despreading, and the transmit power control function is a near / far problem due to the distance difference between the mobile station and the base station. And a function of changing transmission power against instantaneous fluctuation (fading) due to multipath. The absolute synchronous detection function is a function for performing absolute synchronous detection by adding a pilot signal to a data signal and transmitting it in order to obtain a required BER (bit error rate) with lower transmission power.

  In mobile communication, stable communication is required in a variety of dynamically changing environments such as a process in which a mobile station shifts from a stationary state to a high-speed moving state and a process in which the mobile station transitions from an urban environment to a suburban environment. Is done. In particular, in a multipath environment involving reflected waves and delayed waves that have passed through a plurality of transmission paths, fading (instantaneous value fluctuation) occurs due to interference, so that countermeasures are indispensable in mobile communications. Also in the DS-CDMA system, effective fading countermeasures are desired in connection with the above functions.

  However, the DS-CDMA mobile communication has the following problems.

  In general, there are optimum values for the parameters of each part of the communication device for fading that occurs during communication. However, since the fading fluctuation speed varies depending on the moving speed (or fading pitch) of the mobile station, each parameter Is not always set to an optimum value. Therefore, when the parameters are not optimized, the reception characteristics are degraded, and the channel capacity is degraded. In addition, in order to optimize each parameter, it is necessary for the mobile station to estimate its own moving speed.

   FIG. 11 is a diagram illustrating a drop in received signal electric field strength due to fading. The conventional moving speed estimation method estimates the moving speed by monitoring the fluctuation of the reception level. In Patent Document 1, instantaneous fluctuation (differentiation) is measured at a certain time interval on the received signal electric field strength, and the movement speed is estimated because the fluctuation amount can be approximated to the movement speed. In Patent Document 2, the speed is estimated based on the number of times the received signal electric field strength intersects the threshold.

However, as in the case of the FDMA system and the TDMA system, one mobile station occupies one frequency at a certain point in time (the FDMA system occupies one frequency by one mobile station, and the TDMA system uses one frequency. Is divided by a plurality of mobile stations in the time direction, but at a certain point in time, one mobile station is always occupied at that point). In the DS-CDMA system, one frequency is divided into a plurality of mobile stations. Shared by the station. That is, the power allowed for one mobile station is more severely constrained than other multiplexing schemes. When fading occurs as shown in FIG. 12 and the received electric field strength itself is low, the measurement limit of the electric field strength, that is, the noise floor level may be reached at the fading notch. In this case, the method of Patent Document 1 cannot calculate the derivative, and the method of Patent Document 2 provides the same moving speed estimation result regardless of whether a measurement limit has occurred or not. It becomes difficult to grasp the speed change.
JP 2004-88179 A JP-A-10-79701

  An object of the present invention is a mobile station speed estimation circuit and a mobile speed estimation method used in a mobile station or a base station, and a circuit capable of accurately estimating a mobile speed even when fading drops. It is to provide a method. In particular, it is an object of the present invention to provide a circuit and a method capable of accurately estimating the speed of a mobile station even when used in a DS-CDMA system in which the restriction of power allowed for one mobile station is severe.

A first aspect of the present invention is a moving speed estimation circuit that estimates a moving speed based on time-series level fluctuations of a received signal electric field strength, and is surrounded by a portion where the received electric field strength falls and a portion having a predetermined value. A calculating unit that calculates information corresponding to the area of the portion to be detected, and a moving speed estimating unit that estimates a moving speed based on the information calculated by the calculating unit. To realize a moving speed estimation circuit characterized by calculating information corresponding to the area of a triangle formed between two points which are corresponding one point and before and after the notch and have a predetermined value. That is.

A second aspect of the present invention is a moving speed estimation circuit that estimates a moving speed based on time-series level fluctuations of a received signal electric field strength, and is surrounded by a portion where the received electric field strength falls and a portion having a predetermined value. A calculation unit that calculates information corresponding to the area of the portion to be detected, and a movement speed estimation unit that estimates a movement speed based on the information calculated by the calculation unit, wherein the calculation unit has a noise floor level as the drop portion. By implementing information on the area of the trapezoid formed between two points before and after the depressed portion and having a predetermined value, the moving speed estimation circuit is realized. is there.

  ADVANTAGE OF THE INVENTION According to this invention, it is the moving speed estimation circuit and moving speed estimation method of a mobile station used in a mobile station or a base station, Comprising: Even when fading falls, accurate movement speed estimation is attained. In particular, it is possible to accurately estimate the moving speed even in the DS-CDMA system in which power restrictions per mobile station are severe.

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

  FIG. 1 is a block diagram in a first embodiment of a moving speed estimation circuit mounted on a mobile station or base station of the present invention. In the figure, 1 is a received signal level estimation unit, 2 is a normalization unit, 3 is an area calculation unit, and 4 is a speed detection unit.

  The received signal electric field strength of the signal received from the antenna is measured by the received signal level estimation unit. Here, the received signal level measuring unit detects the level at which the signal is not attenuated as 0 dBm, and detects the level at which the signal is attenuated due to instantaneous fluctuation as a negative value. The normalization unit 2 normalizes the value detected as the negative value for the calculation process of the area calculation unit 3 in the subsequent stage.

  FIG. 2 is a diagram illustrating an image of normalization processing. It shows normalization when the dynamic range of the received signal level estimation unit is 0 dBm to -140 dBm. The normalization unit 2 can be realized by an absolute value circuit or the like. In FIG. 1, the normalization unit 2 is required. However, when the reception signal level measurement unit 1 measures the reception signal level at all positive levels of 0 or more, or even when the subsequent area calculation unit 3 is at a negative level. When the area calculation can be performed, the normalization unit 2 is not necessary.

  The reception level normalized by the normalization unit 2 is surrounded by a fading notch (the most attenuated portion) and portions having levels corresponding to a predetermined threshold level before and after the fading notch in the area calculation unit 3. Calculate the area to be measured.

  FIG. 3 is a diagram illustrating an area calculation method under a normal fading environment. In the figure, point B is the fading notch part, point A exists in time series before point B, part corresponding to the area calculation level threshold, and point C exists in time series after point B. , Portions corresponding to the area calculation level threshold are shown. In the case of the situation in FIG. 3, the area calculation is performed on a triangular area with the time interval between point A and point C as the base and the difference in received signal electric field strength between point A (point C) and point B as the height. Part 3 is performed. In this case, the unit of the length of the base is time and the unit of height is dB, so both units are different, but the area calculation is performed as it is (naturally, it may be converted to another unit) ).

  The area calculation result is sent to the moving speed estimation unit 4. The moving speed estimation unit 4 estimates the moving speed based on the area calculation result. When the calculated area of the triangle is large, it is regarded as slow fading (that is, the mobile station moves at a low speed), and when small, it is regarded as fast fading (that is, the mobile station moves at a high speed). The moving speed estimation unit 4 has a correspondence table of area values and speeds, and outputs the corresponding speed as a detection result by referring to the correspondence table.

  However, it is possible to calculate the speed in more detail by having a table in which not only the area but also the value corresponding to the height and base used for the area calculation of the triangle and the speed are associated with each other. This is because in the case of triangles having the same area value, the shorter the base and the longer the height, the faster the fading can be determined. In this case, the area calculation unit 3 may send information on the base and height, not the area value, to the speed detection unit 4 to the movement speed estimation unit 4 (the area value is not necessarily required). In addition, when the areas of the triangles are the same, it can be seen that the longer base has better received signal field strength characteristics as a whole. That is, the received signal quality can be estimated based on the base and height information. The detection of the base and height may be performed by the area calculation unit 3, or other means may be used. Further, the received signal quality estimation may be performed by the movement speed estimation unit 4 or other means may be used.

  Although the first embodiment of the present invention has been described above, the second embodiment corresponding to the case where the received signal electric field intensity reaches the noise floor level will be described below.

  FIG. 4 is a diagram showing a block diagram in a second embodiment of a moving speed estimation circuit mounted on the mobile station or base station of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same members, 5 denotes an area calculation unit, 6 denotes a reception signal determination unit, and 7 denotes a speed estimation unit.

  The processing up to the normalization unit 2 is the same as that in the first embodiment. In addition to the triangular calculation described in the first embodiment, the area calculation unit 5 corresponds to the case where the received signal electric field intensity reaches the noise floor level, but the operation will be described below.

  FIG. 5 is a diagram for explaining an area calculation method when the entire received electric field intensity itself is low and the received signal reaches the noise floor level. In the figure, points A and D are portions corresponding to area calculation level thresholds, and point A exists earlier in time series than point D. Further, points B and C are portions corresponding to the noise floor level, and point B exists earlier in time series than point C. In the case of FIG. 4, the triangle area calculation shown in FIG. Therefore, the time interval between the points A and D is the upper base, the time interval between the points B and C is the lower base, and the received signal electric field between the points A (D) and B (C). The area calculation unit 5 performs trapezoidal area calculation with the intensity difference as the height. Although the area calculation unit 5 also performs the above-described triangle area calculation, the reception signal determination unit 6 instructs whether to perform the triangle area calculation or the trapezoid area calculation.

  The reception signal determination unit 6 receives the measurement result of the reception signal electric field strength from the reception signal level measurement unit 1, and if there is a portion that has reached the noise floor level, instructs the area calculation unit 5 to perform trapezoidal area calculation processing. If the floor level has not been reached, the area calculation unit 5 is instructed to calculate the area of the triangle.

  The calculation result of the area calculation unit 5 is sent to the movement speed estimation unit 7. The moving speed estimation unit 7 estimates the moving speed based on the area calculation result. When the calculated triangle or trapezoid area is large, it is regarded as low-speed fading (that is, the mobile station moves at a low speed), and when small, it is regarded as high-speed fading (that is, the mobile station moves at a high speed). The moving speed estimation unit 7 has a correspondence table of area values and speeds, and outputs the corresponding speed as a detection result by referring to the correspondence table.

  However, if you want to calculate the speed in more detail, in addition to the area, in the case of a triangle, a table that associates the height used for area calculation, the value related to the base and the speed, and in the case of a trapezoid, the upper base (or lower This can be dealt with by having a table that associates the speed and the value related to the height with respect to the bottom or both the upper bottom and the lower bottom). If the triangle has the same area value, the shorter the base and the higher the height, the faster the fading can be judged, and even if the area is the same trapezoid, the longer the height, the faster the fading. This is because it can be determined. In this case, the area calculation unit 5 informs the speed detection unit 7 not the area value but the information about the base and height in the case of a triangle, and the upper base (or the lower base, or the upper base lower base in the case of a trapezoid). Both) and information on the height may be sent to the movement speed estimation unit 7 (the area value is not necessarily required). In addition, when the areas of the triangles are the same, it can be seen that the longer base has better received signal field strength characteristics as a whole. That is, the received signal quality can be estimated based on the base and height information. Detection of the bottom and height, the upper base or the lower base may be performed by the area calculation unit 5 or other means may be used. The received signal quality estimation may be performed by the moving speed estimation unit 7 or other means may be used.

  Furthermore, in the case of a triangle and a trapezoid having the same area, it can be said that the trapezoid has a faster decay speed, and thus the moving speed is faster.

  As described above, it is possible to estimate the quality of the received signal and the moving speed in detail by considering the area value and parameters such as the base, upper base, lower base and height necessary for area calculation. It becomes possible.

  In addition, the area calculation level threshold value in the first and second embodiments can be fixed or variable. However, in the case of fixed, it is necessary to set according to the low case so that the case where the received signal electric field strength is high or low can be dealt with. In the case of variable, it is conceivable to integrate the overall intensity of the received signal electric field strength at a certain time, and to calculate a rough threshold value from the integrated value. In order to be able to do so, a means for changing the time constant of the control loop in the case of sudden change is required. For example, when the instantaneous fluctuation is large, it can be dealt with by reducing the number of integrations.

  Furthermore, the information regarding the moving speed estimated in the first embodiment and the second embodiment is used for controlling various parameters of the mobile communication system in the present invention.

  When the mobile station moves (both the mobile station and the base station), the frequency of the received signal varies. Due to this frequency variation, there is a difference between the frequency of the transmission signal on the transmission side and the frequency of the reception signal on the reception side. Due to the occurrence of this deviation, the complex plane itself is displaced between the transmission side and the reception side, and there is a risk of erroneous signal point determination on the reception side. In AFC (Auto Frequency Control), the phase shift amount is determined by detecting at which phase a known signal (pilot signal, etc.) transmitted from the transmitting side at a known phase is received at the receiving side. It is calculated and replaced with frequency fluctuation to control the frequency of the carrier wave required when judging the signal point of the received signal. It is essential in the mobile communication system to improve the accuracy of signal point judgment. It is one of the components.

  FIG. 6 is a distribution diagram on the complex plane in the case of low speed movement. It shows that the pilot signal transmitted on the I axis was received by receiving a phase rotation that is the influence of the slow fading in the opposite direction to the clock. In the case of low-speed movement, since the phase fluctuation is small, the sensitivity of the loop filter in the AFC unit is deteriorated so that the AFC unit can stably perform phase tracking. This control of the AFC unit can be applied to either a mobile station or a base station.

  FIG. 7 is a distribution diagram of the complex plane in the case of high speed movement. It shows that the pilot signal transmitted on the I axis was received by receiving a phase rotation which is the influence of fast fading in the opposite direction to the clock. In the case of high-speed movement, since the phase fluctuation is large, the sensitivity of the loop filter in the AFC unit is improved so that the AFC unit can perform phase tracking at high speed.

  Further, the angle estimation table of the AFC unit for detecting the phase rotation angle may be changed according to the moving speed. When the movement is fast, it is necessary to prepare a table for the entire complex plane area as shown in FIG. 8, but when the movement is slow, prepare a table with a small complex plane area to cover as shown in FIG. As a result, the bit accuracy can be improved accordingly. As a means for changing the sensitivity of the loop filter of the AFC unit, general means such as JP-A-2-222343 can be used.

  Further, the case where the moving speed estimation circuit of the present invention is applied to AFC has been described above, but the present invention is not limited to this, and cell search frequency, TPC (Transmission Power Control), HCS (Hierarchical Cell Structures) : A configuration in which a small cell for absorbing traffic is arranged in a large cell (an example of which is shown in FIG. 10).

  The cell search frequency is applied as follows. In other words, it can be generally said that the higher the speed of a mobile station, the more opportunities for handoff. By increasing the frequency of cell search for a mobile station that moves at high speed, it is possible to prevent the line from being disconnected before preparing a new line with the base station of the movement destination. Specifically, when the mobile speed estimation circuit determines that the base station is moving at a high speed and the mobile speed estimation circuit determines that the mobile station is moving at a high speed, a signal for controlling the mobile station to increase the cell search frequency is provided. The signal transmitted from the base station to the mobile station may be transmitted to the mobile station at an intentionally lowered level in order to promote cell search. In addition, when the mobile station is provided with a moving speed estimation circuit for the mobile station and determines that the mobile station is moving at a high speed, it can be realized by increasing the frequency of its own cell search.

  The TPC is applied as follows. As described above, in the CDMA system, the power constraint per mobile station is stricter than in other systems, and the signal quality of each mobile station arriving at the base station [for example, SIR (Signal to Interference Ratio: signal to interference ratio)] is transmitted from the base station to the mobile station, indicating whether the transmission power of the mobile station is to be increased or decreased. A mobile station that performs power control based on this TPC command is called TPC. In general, the signal from a mobile station moving at a higher speed has a greater fading level fluctuation. However, using this property, a mobile station moving at a higher speed transmits with one TPC command. By increasing the level control range, it is possible to achieve early level stabilization. Specifically, the mobile station can be realized by providing a mobile station movement speed estimation circuit in the base station and transmitting the TPC command transmitted to the mobile station with a level control width corresponding to the movement speed to the mobile station. In addition, a mobile speed estimation circuit is provided for the mobile station to estimate its own mobile speed. With this estimated value, transmission power control is performed by changing the control width in response to a TPC command increase or decrease command received from the base station It can also be realized by doing.

  The HCS is applied as follows. In other words, HCS is a technology that places a small cell in a large cell to absorb the traffic in a large-scale stadium, etc., where traffic is concentrated locally to absorb the traffic. However, even if a mobile station moving at high speed is handed off from a large cell to a small cell, it is expected that it will soon return to the area of only the large cell beyond the area of the small cell. Encouraging handoff to a small cell increases the chance of handoff and increases the load on the entire system. Therefore, the system load can be reduced by controlling the mobile station moving at high speed so as not to handoff to a small cell in the HCS area. Specifically, a mobile station speed estimation unit is provided on the base station side, and even if there is a handoff request from this mobile station to a small cell, it will not be accepted and communication will continue as a large cell. Can be realized. In addition, if the mobile station itself has a moving speed estimation circuit, and the mobile speed estimation circuit determines that it is moving at high speed even if it is an opportunity to request handoff to a small cell of HCS, This can also be realized by controlling so that a handoff request to a small cell is not sent to the base station.

  In addition, for the received signal quality estimation circuit described in the first embodiment and the second embodiment, this estimation result can be applied to the AFC, cell search frequency, and handoff trigger judgment in the same manner as the movement speed estimation circuit. Needless to say, the present invention can be applied to all systems controlled by an error rate. For example, it can be utilized as TPC outer loop control, packet retransmission control, base station selection information during SSDT (Site Selection Diversity Transmission), and the like.

  AFC is applied as follows. That is, when the quality result estimated by the received signal quality estimation circuit is poor, the AFC unit may not be able to follow, so control is performed so as to follow at high speed. Needless to say, the control of the AFC unit can be applied to both the mobile station and the base station.

  The cell search frequency is applied as follows. That is, when the quality result estimated by the reception signal quality estimation circuit is poor, the cell search frequency is controlled to be high, and if there is a line with good reception quality, handoff is performed early. Specifically, a reception signal quality estimation circuit is provided in the base station, and when the signal quality from the mobile station deteriorates, the mobile station may be instructed to increase the cell search frequency, or the mobile station The level of the transmission signal to the mobile station may be lowered so as to encourage the handoff of the station. It can also be realized by providing a received signal quality estimation circuit in the mobile station and performing control to increase the cell search frequency when the quality of the signal from the base station deteriorates.

  The TPC outer loop control can be applied as follows. As described above, the TPC is controlled so as to achieve a desired channel quality. However, in order to realize the desired channel quality, the channel quality of the signal whose transmission power is controlled by the TPC is measured, and the desired channel quality is obtained. If the channel quality is not equal to that of the TPC outer loop control, it is determined that the desired value (target value) of the channel quality itself is an incorrect value for the TPC control and the desired value is changed. Specifically, this can be realized by providing a received signal quality estimation circuit in the mobile station or base station and changing the TPC target value according to the quality of the received signal.

  The packet retransmission control is applied as follows. That is, when the quality result estimated by the received signal quality estimation circuit is bad, it is determined that the content of the received packet is incorrect, and the transmission side is requested to retransmit the packet. Needless to say, it can be applied to both mobile stations and base stations.

The SSDT is applied as follows. The SSDT means that when a signal is transmitted from a plurality of base stations to a mobile station, a base station having a good channel quality is designated and transmitted. The mobile station is provided with a received signal quality estimation circuit, By estimating the channel quality of the received signal from the base station, the base station to be transmitted can be designated. Further, a reception signal channel quality estimation circuit from the mobile station may be provided on the base station side, and control may be performed so that a base station with a good reception signal from the mobile station becomes a base station that transmits to the mobile station.
(Appendix 1) A moving speed estimation circuit that estimates a moving speed based on time-series level fluctuations in received signal electric field strength,
An arithmetic unit that calculates information corresponding to the area of the portion surrounded by the portion where the received electric field strength falls and the portion having a predetermined value;
A movement speed estimation circuit comprising: a movement speed estimation section that estimates a movement speed based on information calculated by the calculation section. (1)
(Supplementary note 2) The moving speed estimation circuit according to supplementary note 1, wherein
The calculation unit calculates information corresponding to an area of a triangle formed between the point where the sagging portion corresponds to a fading notch, and two points having a predetermined value before and after the notch. A moving speed estimation circuit. (2)
(Supplementary note 3) The moving speed estimation circuit according to supplementary note 1, wherein
The calculation unit calculates information relating to the area of the trapezoid formed between the two points at which the depressed part becomes a noise floor level and the two points having a predetermined value before and after the depressed part. A moving speed estimation circuit characterized by the above. (3)
(Supplementary note 4) The moving speed estimation circuit according to supplementary note 1, wherein
The moving speed estimation circuit further comprising a control unit that changes a loop constant of a loop filter in the automatic speed control circuit according to a moving speed estimated value of the moving speed estimation unit.
(Supplementary note 5) The moving speed estimation circuit according to supplementary note 1, wherein
The moving speed estimation circuit further comprising a control unit that changes a power control width of transmission power control according to a moving speed estimated value of the moving speed estimation unit.
(Supplementary note 6) The moving speed estimation circuit according to supplementary note 1, wherein
A moving speed characterized by further comprising a control unit for handing off the mobile station to the small cell area based on the moving speed estimated value of the moving speed estimating unit when the cell area of the base station has a smaller cell area. Estimating circuit.
(Supplementary note 7) The moving speed estimation circuit according to supplementary note 2,
The calculation unit corresponds to the base of the triangle and has information about a time interval between two points having the predetermined value, and corresponds to the height of the triangle, and the value of the portion corresponding to the predetermined value and the notch And calculating information regarding the difference in level as information corresponding to the area,
The moving speed estimation circuit, wherein the moving speed estimation unit estimates a moving speed based on information on the base and information on height.
(Supplementary note 8) The moving speed estimation circuit according to supplementary note 3, wherein
The arithmetic unit corresponds to the upper base of the trapezoid, and information on a time interval between two points having the predetermined value, or corresponds to the lower base of the trapezoid, and between two points corresponding to the noise floor level. While calculating at least one of the information on the time sense and the information on the level difference between the predetermined value corresponding to the height of the trapezoid and the noise floor level as information corresponding to the area,
The moving speed estimation circuit estimates the moving speed based on information on at least one of the upper and lower bases and information on height.
(Supplementary note 9) A moving speed estimation method for estimating a moving speed based on time-series level fluctuations of received signal electric field strength,
Calculate the information corresponding to the area of the portion surrounded by the portion where the received electric field strength falls and the portion having a predetermined value,
A moving speed estimation method, wherein a moving speed is estimated from information corresponding to the area. (4)
(Supplementary Note 10) A reception signal quality estimation circuit for estimating the quality of a reception signal based on time-series level fluctuations of the reception signal electric field strength,
An arithmetic unit that calculates information corresponding to the area of the portion surrounded by the portion where the received electric field strength falls and the portion having a predetermined value;
A reception signal quality estimation circuit comprising: a quality estimation unit configured to estimate the quality of the reception signal based on information calculated by the calculation unit. (5)
(Supplementary note 11) The received signal quality estimation circuit according to supplementary note 10, wherein
A received signal quality estimation circuit, further comprising a control unit that changes a frequency of cell search according to a quality estimation value of the quality estimation unit.
(Supplementary note 12) The moving speed estimation circuit according to supplementary note 10,
A received signal quality estimation circuit, further comprising a control unit that performs handoff control based on the quality estimation value of the quality estimation unit.
(Supplementary note 13) A received signal quality estimation method for estimating the quality of a received signal based on time-series level fluctuations of the received signal electric field strength,
Calculate the information corresponding to the area of the portion surrounded by the portion where the received electric field strength falls and the portion having a predetermined value,
A received signal quality estimation method, wherein quality of a received signal is estimated from information on the area.

It is a block diagram of the moving speed estimation circuit in the first embodiment. It is a figure which shows the image of a normalization process. It is a figure explaining the area calculation method in a normal fading environment. It is a block diagram of the moving speed estimation circuit in 2nd Embodiment. It is a figure explaining the area calculation method in the case of reaching a noise floor level. It is a distribution map in the complex plane in the case of low-speed movement. It is a distribution map in the complex plane in the case of high-speed movement. It is a figure which shows the angle estimation table with respect to the whole complex plane area | region. It is a figure which shows the small angle estimation table of the complex plane area | region to cover. It is a figure which shows the example of HCS. It is a figure which shows the fall of the received signal electric field strength by fading. It is a figure which shows the fall of the received signal electric field strength which reaches a noise floor level.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception signal level measurement part 2 Normalization part 3 Area calculation part 4 Speed detection part 5 Area calculation part 6 Reception signal determination part 7 Speed detection part

Claims (4)

A moving speed estimation circuit that estimates a moving speed based on time-series level fluctuations in received signal electric field strength,
An arithmetic unit that calculates information corresponding to the area of the portion surrounded by the portion where the received electric field strength falls and the portion having a predetermined value;
A moving speed estimation unit that estimates a moving speed based on information calculated by the calculation unit;
The calculation unit calculates information corresponding to an area of a triangle formed between the point where the sagging portion corresponds to a fading notch, and two points having a predetermined value before and after the notch. A moving speed estimation circuit. A moving speed estimation circuit that estimates a moving speed based on time-series level fluctuations in received signal electric field strength,
An arithmetic unit that calculates information corresponding to the area of the portion surrounded by the portion where the received electric field strength falls and the portion having a predetermined value;
A moving speed estimation unit that estimates a moving speed based on information calculated by the calculation unit;
The calculation unit calculates information relating to the area of the trapezoid formed between the two points at which the depressed part becomes a noise floor level and the two points having a predetermined value before and after the depressed part. A moving speed estimation circuit characterized by the above. A moving speed estimation method for estimating a moving speed by time-series level fluctuations of received signal electric field strength,
A calculation step for calculating information corresponding to an area of a portion surrounded by a portion where the received electric field strength falls and a portion having a predetermined value;
A moving speed estimation step for estimating a moving speed based on information corresponding to the area,
In the calculation step, the depression portion is one point corresponding to a fading notch, and information corresponding to an area of a triangle formed between two points having a predetermined value before and after the notch is calculated. To do
A moving speed estimation method characterized by the above. A moving speed estimation method for estimating a moving speed by time-series level fluctuations of received signal electric field strength,
A calculation step of calculating information corresponding to the area of the portion surrounded by the portion where the received electric field strength falls and the portion having a predetermined value;
A moving speed estimation step for estimating a moving speed based on information corresponding to the area,
In the calculating step, information about the area of the trapezoid formed between the two points at which the depressed part becomes a noise floor level and the two points having a predetermined value before and after the depressed part is calculated.
A moving speed estimation method characterized by the above.

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