JP2005328355A - Communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain communication equipment capable of reducing average transmission power as compared with conventional equipment. <P>SOLUTION: The invented communication equipment is communication equipment on receiving side for controlling transmission power on the basis of a compared result between the receiving quality measurement result of a pilot symbol in received symbols and a receiving quality target value, and at the time of detecting a receiving error of a symbol other than the pilot symbol, controlling to increase the receiving quality target value is provided with a pilot symbol receiving error detection part 11 for detecting a receiving error of the pilot symbol on the basis of a known pilot symbol pattern, a TPC symbol generation part 6 for controlling transmission power on the basis of the detection error of the pilot symbol receiving error in addition to transmission power control based on the compared result of the receiving quality values and so on. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication apparatus that performs transmission power control based on a comparison result between reception quality of a received pilot symbol and a target value of reception quality, and particularly increases the reception quality target value due to occurrence of a reception error. The present invention relates to a communication device that performs control.

  For example, in a digital wireless communication system that performs communication between a base station and a mobile station each having a transmitter and a receiver, transmission power control is performed so as to keep a desired reception quality constant with a minimum transmission power. . In the cellular system using the same frequency, an increase in base station transmission power to a specific user leads to an increase in interference power of other users, which causes a reduction in cell capacity (number of users that can be accommodated in one cell). It is important to reduce transmission power by transmission power control. Note that the transmission power control can be improved in performance by increasing the accuracy of reception quality measurement, for example.

  Below, as a prior art, the case where the reception error of a reception pilot symbol is used for transmission power control is demonstrated (refer patent document 1), for example.

  In the following Patent Document 1, a reception pilot symbol reception error is measured by a reception side communication device (base station or mobile station), and the reliability of the received TPC (Transmission Power Control) symbol is calculated. Then, the transmission power to the opposite device is controlled according to the calculated reliability of the TPC symbol. The TPC symbol is used to request the opposite device to change the transmission power. For example, when requesting an increase in transmission power, (1, 1) is transmitted and a decrease in transmission power is requested. Transmits (-1, -1).

JP 2004-015354 A

  In a conventional communication apparatus, for example, transmission power control is performed in a fading propagation path so that the transmission power follows the fading propagation loss with high accuracy. FIG. 10 is a diagram illustrating how transmission power is made to follow fading propagation loss with high accuracy. Specifically, FIG. 10-1 is a diagram illustrating propagation loss due to fading, and FIG. It is a figure which shows the transmission power in a base station or a mobile station. FIG. 10-1 shows that the larger the value on the vertical axis, the larger the propagation loss and the worse the propagation state. Also, FIG. 10-2 shows that the transmission power is increased by the transmission power control as the propagation state is worse.

  However, in the conventional communication apparatus, for example, when the propagation environment is very good, that is, when the propagation loss due to fading is very small, the transmission power is excessively reduced, and a CRC (Cyclic Redundancy Check) error occurs. (See FIG. 1-2). When a reception error such as a CRC error occurs, for example, when control is performed to increase the target value of reception quality, the target value of reception quality is set even though the propagation environment is very good. As a result, there is a problem that the average transmission power increases.

  The present invention has been made in view of the above, and as described above, even when control is performed to increase the reception quality target value due to the occurrence of a reception error, the average transmission power is made higher than in the past. An object is to obtain a communication device that can be reduced.

  In order to solve the above-described problems and achieve the object, a communication apparatus according to the present invention performs transmission power control based on a comparison result between a reception quality measurement result of a pilot symbol in a reception symbol and a reception quality target value. A reception-side communication device that performs control to increase the reception quality target value when a reception error of a symbol other than the pilot symbol is detected, wherein the reception error of the pilot symbol is determined based on a known pilot symbol pattern. In addition to the pilot reception error detection means for detecting (corresponding to the pilot symbol reception error detection unit 11 in the embodiment described later) and transmission power control based on the comparison result of the reception quality, further detection of the reception error of the pilot symbol Transmission power control means for performing transmission power control based on the result (corresponding to uplink TPC symbol generator 6) Characterized in that it comprises a and.

  According to the present invention, the predetermined processing of the pilot reception error detection means and the transmission power control means performs control such as temporarily increasing the downlink transmission power, for example, to determine the timing of occurrence of reception errors such as data symbols. I decided to delay. That is, the increase timing of the reception quality target value is delayed.

  According to the present invention, even when the reception quality is deteriorated, control is performed to temporarily increase the downlink transmission power to delay the timing of occurrence of reception errors such as data symbols. The reception quality target value is lowered, and as a result, there is an effect that the average downlink transmission power can be reduced.

  Embodiments of a communication apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a communication device according to the present invention. The communication apparatus of Embodiment 1 includes, for example, a despreading unit 1, a rake combining unit 2, a decoding unit 3, a reception error detection unit 4, a reception quality measurement unit 5, and an uplink TPC symbol generation unit (TPC: Transmission Power Control) 6, reception quality target value (1) setting unit 7, reception quality target value (2) storage unit 8, switch 9, comparator 10, pilot symbol reception error detection unit (PED unit) ) 11 and a pilot symbol storage unit (PM unit) 12 that holds a known pilot symbol pattern.

  The transmission power control in the present embodiment is a wireless communication system in which a communication apparatus according to the present invention, that is, a base station and a mobile station each having a transmitter and a receiver transmit and receive symbols phase-modulated between the apparatuses. Here, a case will be described in which the transmission power control in the present embodiment is applied to, for example, a W-CDMA (Wideband-Code Division Multiple Access) system.

  Hereinafter, as an example, a case will be described in which a mobile station operating as a communication apparatus according to the present invention performs transmission power control using reception errors of received pilot symbols. Here, the reception error of the received pilot symbol is used to control the transmission power to the own device.

  In the transmission power control assumed by the present invention, reception quality such as SIR (Signal to Interference Ratio) and CIR (Carrier to Interference Ratio) is measured, and a predetermined reception quality target value (target SIR, etc.) is satisfied. So that the transmission power is controlled. The reception quality target value is controlled by a reception error rate (BLER (Block Error Rate)) determined in accordance with required service quality (QoS: Quality of Service). BLER indicates an error occurrence rate due to CRC (Cyclic Redundancy Check) or the like added to detect an error in units of a plurality of information bits.

  Here, before explaining the operation of the communication apparatus according to the present embodiment, an outline of transmission power control in the W-CDMA system will be described with reference to the drawings. FIG. 2 is a diagram illustrating a configuration example of a mobile station in the W-CDMA system.

  First, the despreading unit 1 performs despreading for each multipath on a received signal spread over a wide band, and extracts a desired received symbol. The extracted received symbols are transferred to the reception quality measuring unit 5 by the switch 9 and the other data symbols and the like are transferred to the rake combining unit 2 by the switch 9.

  Next, the transferred data symbols are subjected to rake combining by the rake combining unit 2 and decoded by the decoding unit 3, and then the reception error detecting unit 4 detects reception errors of the decoded data. The reception quality target value (2) storage unit 8 is set with a reception quality target value (BLER target or the like) for a reception error, and this is set as, for example, a reception quality target value (2). The reception quality target value (2) is used, for example, to control the reception quality target value (1) that is the SIR target. Normally, when a reception error (such as a CRC error) is detected by the reception error detection unit 4, the reception quality target value (1) is increased. On the other hand, if there is no reception error, the reception quality target value (1) is increased. Decrease by a smaller amount than the above increase. As the decrease amount, a method of multiplying the increase amount by the reception quality target value (2) or the like is used.

  FIG. 3 is a diagram illustrating an example of a case where the increase amount is multiplied by the reception quality target value (2) to obtain the decrease amount, and the vertical axis represents the magnitude of the reception quality target value (1). An arrow indicates a point in time when a reception error is detected by the reception error detection unit 4. For example, when the increase amount is 1 dB and the target BLER is 0.01, the decrease amount is 0.01 dB. Thus, the reception quality target value (1) is greatly increased at the time of reception error detection, and the reception quality target value (1) set by the reception quality target value (1) setting unit 7 is transferred to the comparator 10. The

  On the other hand, reception quality measuring section 5 measures reception quality using pilot symbols. This measured value is compared with the reception quality target value (1) by the comparator 10. The comparison result is transferred to the uplink TPC symbol generator 6. For example, when the measured value is larger than the reception quality target value (1), the TPC symbol generator 6 generates a TPC symbol for reducing transmission power. If the measured value is smaller than the received quality measured value (1), an uplink TPC symbol for increasing the transmission power is generated, and the base station is requested to change the transmission power.

  In the transmission power control in the W-CDMA system, the processing flow of the despreading unit 1, the switch 9, the reception quality measurement unit 5, and the uplink TPC symbol generation unit 6 is called inner loop transmission power control, and inner loop transmission is performed. In the power control, an operation for causing the reception quality measurement value to follow the reception quality target value (1) is performed. The processing flow of the reception error detection unit 4, the reception quality target value (1) setting unit 7, and the comparator 10 is called outer loop transmission power control. In the outer loop transmission power control, the reception quality target value (1) is set. An operation for tracking the reception quality target value (2) is performed.

  Next, based on the transmission power control of the W-CDMA system, the operation of the communication apparatus according to the present embodiment will be described with reference to FIG. In addition, about the structure similar to FIG. 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, only processing different from FIG. 2 will be described.

  In the mobile station (communication device) of the present embodiment, first, the pilot symbol in the received symbol extracted by the despreading unit 1 is transferred to the reception quality measuring unit 5 and the PED unit 11 by the switching operation of the switch 9. The other data symbols and the like are transferred to the rake combining unit 2.

  Next, the PED unit 11 reads the pilot symbol pattern from the PM unit 12 and detects a reception error of the received pilot symbol. As a specific detection method, for example, a reception error is detected by exclusive OR of a pilot symbol pattern and a hard decision result by a signal point of a received pilot symbol. Here, the PED unit 11 receives 1 to 8 pilot symbols during one cycle of the inner loop transmission power control.

  Next, in addition to the processing described with reference to FIG. 2, the uplink TPC symbol generation unit 6 further performs TPC symbol generation processing based on the reception error detection result of the received pilot symbols. That is, when the PED unit 11 receives a plurality of pilot symbols during one cycle of the inner loop transmission power control, the uplink TPC symbol generation unit 6 increases the transmission power if, for example, the number of reception errors is half or more. A TPC symbol is generated. Further, when the number of received pilot symbols is one symbol during the one period, the uplink TPC symbol generation unit 6 generates, for example, a TPC symbol for increasing transmission power when a reception error of the received pilot symbol is detected. To do.

  In the present embodiment, the processing of the PED unit 11 and the uplink TPC symbol generation unit 6 can temporarily increase the transmission power before the reception error detection unit 4 detects a reception error such as a data symbol. Therefore, the timing at which the reception quality target value (1) setting unit 7 raises the reception quality target value (1) can be delayed. FIG. 4 is a diagram illustrating an example of a state of the reception quality target value (1) according to the present embodiment. For example, the mobile station of the present embodiment notifies the base station to temporarily increase the downlink transmission power when the number of pilot symbol reception errors exceeds a specific ratio. Therefore, in the conventional case, as shown in FIGS. 3 and 4, the reception error is detected at the time of the white arrow, but in this embodiment, the downlink transmission power is temporarily increased. The timing for increasing the reception quality target value (1), that is, the detection timing of a reception error such as a data symbol can be delayed to, for example, the timing of the black arrow shown in FIG.

  In the present embodiment, for example, a function for rake combining received pilot symbols may be added to the PED unit 11 in order to realize performance improvement by rake combining even when receiving pilot symbol errors are detected. Further, the pilot symbols after processing in the rake combining unit 2 may be transferred to the PED unit 11. Thereby, the detection accuracy of reception errors can be increased. In this embodiment, the criterion for determining the increase in transmission power is, for example, more than half of reception errors in the received pilot symbols, but this criterion is variable, and the accuracy of transmission power control is improved. It is good also as changing arbitrarily.

  As described above, in the present embodiment, the predetermined processing of the PED unit 11 and the uplink TPC symbol generation unit 6 performs control to temporarily increase the downlink transmission power, and the generation timing of reception errors such as data symbols. It was decided to delay. That is, the increase timing of the reception quality target value (1) is delayed. As a result, the reception quality target value (1) generally decreases, and as a result, the average downlink transmission power can be reduced.

  In addition, although this Embodiment demonstrated the case where the transmission power (downlink transmission power) from a base station to a mobile station was demonstrated, it is not restricted to this, The transmission power (uplink transmission power) from a mobile station to a base station The same applies to the case of controlling. In this case, there is also an effect of power saving of the mobile station.

Embodiment 2. FIG.
Next, the operation of the communication apparatus according to the second embodiment will be described. In Embodiment 2, when reception quality measurement is performed at a mobile station, not only reception pilot symbols but also reception symbols other than pilot symbols are set as reception quality measurement targets. In addition, about the structure similar to FIG. 1 of Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, only processing different from the first embodiment will be described.

  FIG. 5 is a diagram illustrating a configuration example of the communication apparatus according to the second embodiment of the present invention. In addition to the configuration of FIG. 1 of the first embodiment, the communication apparatus of the second embodiment has, for example, a switch 21, an inverse modulation unit 22 that demodulates pilot symbols, and a plurality of symbols as I and Q. Coherent adders 23, 25, and 26 for adding each component, multiplier 24 for multiplying both I and Q components by -1, adders 27 and 28 for adding an input signal for each I and Q component, and adders A determination unit 29 that determines an amplitude value of the addition result of 27 and 28; and a selection unit 30 that selects a symbol to be used for reception quality measurement based on the determination result.

  Here, before explaining the characteristic operation of the communication apparatus according to the second embodiment, a presupposed technique will be described.

  For example, in Embodiment 2, TPC symbols are used as received symbols other than pilot symbols. Since this TPC symbol is a received symbol whose modulation signal is unknown, it is necessary to determine the modulation signal. The maximum likelihood determination is used as the determination method.

  In addition, W-CDMA symbols are basically subjected to QPSK (Quadrature Phase Shift Keying) modulation, and each symbol is represented by I (In-Phase) and Q (Quadrature-Phase) components. FIG. 6 is a diagram illustrating a W-CDMA downlink slot format. As shown in FIG. 6, a pilot symbol and a TPC symbol exist in one slot (0.67 ms). This TPC symbol includes information for controlling uplink transmission power. In the present embodiment, reception symbols other than TPC symbols may be used as reception quality measurement targets.

  FIG. 7 is a diagram showing the timing of transmission power control in W-CDMA. Specifically, FIG. 7-1 shows a part of the downlink (DPCH: Dedicated Physical Channel) received by the mobile station. FIG. 7-2 is a diagram illustrating a part of the uplink (DPCCH: Dedicated Physical Control Channel) transmitted from the mobile station to the base station. Actually, a plurality of transmission channels are multiplexed on both the downlink and the uplink. As downlink transmission channels, there are CPICH (Common Pilot Channel) and the like in addition to DPCH. Here, the TPC symbol (TPC # 1) in slot A in FIG. In addition, it is assumed that pilot # 2 in slot A has its transmission power (base station transmission power) changed based on the reception quality measurement result using pilot # 1 in the previous slot. In order to change the transmission power based on the reception quality measurement result of pilot # 1, it is necessary to reflect the reception measurement result of pilot # 1 in the uplink TPC symbol (TPC # 2).

  When TPC # 1 shown in FIG. 7-1 is a reception quality measurement target, considering the processing time, it is difficult to keep the reception quality measurement result in time for the transmission time of TPC # 2 shown in FIG. 7-2. Therefore, for TPC # 1, the reception quality measurement is performed together with pilot # 2 in slot A. Note that this is not the case when a delay in transmission power control is allowed or when a received symbol other than a TPC symbol is a reception quality measurement target.

  Subsequently, a characteristic operation of the communication apparatus according to the present embodiment will be described in detail with reference to FIG. First, pilot symbols in the received symbols extracted by the despreading unit 1 are transferred to the reception quality measuring unit 5 and the demodulating unit 22 by the switch 9. Further, the TPC symbol in the received symbol is transferred to the coherent adder 25 and the multiplier 24 by the switch 9 and the switch 21. Other data symbols and the like (Data 1, TFCI, Data 2 in FIG. 6) are transferred to the rake combining unit 2 by the switch 9.

  Next, the inverse modulation unit 22 performs inverse modulation on the received pilot symbols using a known pilot symbol pattern. By performing inverse modulation on a signal subjected to phase modulation such as QPSK, the phase angle of each symbol generated by phase modulation is removed, and the phase of each symbol is made uniform. Note that inverse modulation can be performed by multiplying the complex conjugate of the phase points. The coherent adder 23 adds a plurality of pilot symbols for each of the I and Q components, and transfers the addition result to the adders 27 and 28. Note that coherent addition is not performed when there is a single pilot symbol.

  On the other hand, the TPC symbol is an unknown received symbol when it passes through the switch 903, but it is certain that it is transmitted at (1, 1) or (-1, -1). , (−1, −1) is assumed, inverse modulation (I and Q components are multiplied by −1) is performed, and the result is transferred to the coherent adder 26. If (1, 1), no inverse modulation is necessary (that is, inverse modulation is performed assuming the case of (1, 1)), and the data is transferred to the coherent adder 25 as it is.

  Next, when a plurality of TPC symbols are transmitted, the same symbol is repeatedly transmitted. Therefore, the coherent adders 25 and 26 perform coherent addition for adding the plurality of symbols for each of the I and Q components. For example, when receiving TPC symbols after two symbols are demodulated, symbols that are demodulated assuming (1,1) are symbols that are demodulated assuming (-1, -1). Are coherently added. The signals after the coherent addition are transferred to adders 27 and 28, respectively. If there is a single TPC symbol, coherent addition is not performed.

Next, the adders 27 and 28 add the coherent addition value of the pilot symbol after inverse modulation by the inverse modulation unit 22 to each coherent addition value of the TPC symbol after inverse modulation. The adder 27 outputs the addition value A ¹ as the addition result, and the adder 28 outputs the addition value A ⁻¹ as the addition result.

Next, the determination unit 29 obtains the signal amplitude of the added values A ¹ and A ⁻¹ , performs maximum likelihood determination using the signal amplitude as a likelihood, and transfers the determination result to the selection unit 30. The selection unit 30 selects a TPC symbol after inverse modulation used for reception quality measurement. When a signal having the maximum signal amplitude is selected from the signals after addition by the adders 27 and 28 (maximum likelihood determination), it is possible to select a TPC symbol after inverse modulation that is closest to the phase of the pilot symbol after inverse modulation.

  Finally, the reception quality measurement unit 5 measures the reception quality of the selected TPC symbol in the same manner as the pilot symbol. In addition, it is also possible to pass the pilot symbol after passing through the inverse modulation unit 22 to the reception quality measurement unit 5. Thereafter, in the communication apparatus according to the present embodiment, in addition to the above-described transmission power control based on pilot symbol reception errors, transmission power control based on reception quality measured using pilot symbols and TPC symbols is performed.

  As described above, in this embodiment, in addition to pilot symbols, TPC symbols are also subjected to reception quality measurement, so that the same effect as in the first embodiment described above can be obtained, and further, reception quality measurement can be performed. The time is extended and the reception quality measurement with high accuracy can be performed. Thereby, more efficient transmission power control can be implemented.

Embodiment 3 FIG.
Next, the operation of the communication apparatus according to the third embodiment will be described. In the third embodiment, multipath is utilized based on the configuration of the second embodiment described above. In addition, about the structure similar to FIG. 1 of Embodiment 1 mentioned above and FIG. 5 of Embodiment 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, only processing different from that of the second embodiment will be described.

  FIG. 8 is a diagram illustrating a configuration example of the communication apparatus according to the third embodiment of the present invention. The communication apparatus according to the third embodiment includes a despreading unit 1, switching units 9 and 21, demodulating unit 22, coherent adders 23, 25, and 26, multipliers 24, adders 27 and 28, and phase compensation for each path. And an adder 42 and 43 that add outputs for each path, a determination unit 29, and a reception quality measurement unit 5.

  Here, a characteristic operation of the communication apparatus according to the present embodiment will be described in detail with reference to FIG. Although a part of FIG. 8 is multiplexed, when there are N paths (N: natural number), the same processing as in the above-described second embodiment is performed for each path (partially different processing is present). To implement.

Therefore, the outputs of the adders 27 and 28 include, for each path, an addition value A ¹ (k) (k = 1, 2,..., N) of the coherent addition value by the coherent adder 25 and the coherent addition value of the pilot symbol. ) And the addition value A ⁻¹ (k) (k = 1, 2,..., N) of the coherent addition value by the coherent adder 26 and the coherent addition value of the pilot symbol. Hereinafter, the kth path is referred to as path #k (k = 1, 2,..., N).

Next, the phase compensation unit 41 uses the path # 1 (first path) as a reference path, and further includes pilot symbols in the CPICH or DPCH of the path # 1, and pilot symbols in the CPICH or DPCH of the path #k. , The phase difference between the reference path and the path #k is estimated. Based on the estimation result, phase compensation is performed on the added values A ¹ (k) and A ⁻¹ (k) of the path #k. This phase compensation processing is performed for all paths.

After the phase compensation, the adder 42 calculates B ¹ = A ¹ (1) + A ¹ (2) +... + A ¹ (N), while the adder 43 calculates B ⁻¹ = A ^−1. (1) + A ⁻¹ (2) +... + A ⁻¹ (N) is calculated. The added values B ¹ and B ⁻¹ are transferred to the determination unit 29.

  Next, in the determination part 29, each signal amplitude is calculated | required and maximum likelihood determination is implemented by making this signal amplitude into likelihood. The determination result is transferred to the selection unit 30 for each path.

  Next, the selection unit 30 selects a TPC symbol used for reception quality measurement for each path. The determination result to be used is common to each path. Therefore, in all the paths, the TPC symbol demodulated by (1, 1) or the TPC symbol demodulated by (-1, -1) is selected.

  Finally, the reception quality measurement unit 5 uses the TPC symbols selected for each path in addition to the pilot symbols for reception quality measurement. Thereafter, in the communication apparatus according to the present embodiment, in addition to the above-described transmission power control based on pilot symbol reception errors, transmission power control based on reception quality measured using pilot symbols and TPC symbols is performed.

  As described above, according to the present embodiment, even when the transmission power is excessively reduced and many TPC symbol reception errors occur, the same processing as in Embodiment 1 is performed according to the number of reception errors. Thus, by temporarily increasing the downlink transmission power, the same effect as in the first embodiment can be obtained. On the other hand, when the transmission power is large to some extent, the transmission power control with high accuracy can be performed by increasing the reception quality measurement target.

  In this embodiment, pilot symbols in DPCH are used for likelihood calculation. However, the present invention is not limited to this. For example, CPICH multiplexed on DPCH can also be used. In this embodiment, the TPC symbol after demodulation and the pilot symbol after demodulation are directly coherently added to the likelihood calculation. However, weighted addition may be performed here. Depending on the setting of weighting, it is possible to set whether priority is given to the accuracy of transmission power control or reduction of transmission power.

Embodiment 4 FIG.
Next, the operation of the communication apparatus according to the fourth embodiment will be described. In the fourth embodiment, the accuracy of the maximum likelihood determination of the TPC symbol in the second and third embodiments is increased. The configuration of the communication apparatus according to the fourth embodiment is the same as that of FIG. 5 of the second embodiment or FIG. 8 of the third embodiment.

  In the present embodiment, for example, the phase variation due to fading is compensated when the pilot symbol and TPC symbol that are the reception quality measurement targets are separated in time (see FIG. 6). Specifically, for example, as shown in FIG. 9, the CPICH (FIG. 9, a) in the TPC symbol transmission time zone and the pilot symbol are utilized by utilizing the fact that CPICH is multiplexed in the W-CDMA downlink. The phase difference between the TPC symbol and the pilot symbol is estimated using CPICH in the transmission time zone (FIG. 9, b), and the phase variation is compensated by multiplying the complex conjugate of the estimated value by the TPC symbol. Note that the pilot in the DPCH can also be used for phase compensation.

  As described above, in the present embodiment, the phase variation due to fading is compensated when the pilot symbol and the TPC symbol of the reception quality measurement target are temporally separated. Thereby, the accuracy of the maximum likelihood determination of the TPC symbol can be further increased.

  As described above, the communication apparatus according to the present invention is useful for a communication system that employs the W-CDMA system, and in particular, performs transmission power control based on the comparison result between the reception quality of the reception symbol and the reception quality target value. Suitable as a communication device to perform.

It is a figure which shows the structural example of Embodiment 1 of the communication apparatus concerning this invention. It is a figure which shows the structural example of the mobile station in a W-CDMA system. It is a figure which shows an example in the case of calculating | requiring a decreasing amount by multiplying a reception quality target value (2) with an increasing amount. 6 is a diagram illustrating an example of a state of a reception quality target value (1) according to Embodiment 1. FIG. It is a figure which shows the structural example of Embodiment 2 of the communication apparatus concerning this invention. It is a figure which shows the slot format of the downlink of W-CDMA. It is a figure which shows a part of downlink (DPCH) received by a mobile station. It is a figure which shows a part of uplink (DPCCH) transmitted from a mobile station to a base station. It is a figure which shows the structural example of Embodiment 3 of the communication apparatus concerning this invention. FIG. 10 is a diagram illustrating a method for compensating for phase variation due to fading in the fourth embodiment. It is a figure which shows the propagation loss by fading. It is a figure which shows the transmission power in a communication apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Despreading part 2 Rake combining part 3 Decoding part 4 Reception error detection part 5 Reception quality measurement part 6 Uplink TPC symbol generation part 7 Reception quality target value (1) setting part 8 Reception quality target value (2) Storage part 9 Switch 10 Comparator 11 Pilot Symbol Reception Error Detection Unit (PED Unit)
12 Pilot symbol storage unit (PM unit) 12
DESCRIPTION OF SYMBOLS 21 Switcher 22 Inverse modulation part 23,25,26 Coherent adder 24 Multiplier 27,28 Adder 29 Judgment part 30 Selection part 41 Phase compensation part 42,43 Adder

Claims (6)

Transmit power control is performed based on the comparison result between the reception quality measurement result of the pilot symbol in the reception symbol and the reception quality target value, and the reception quality target value is increased when a reception error of a symbol other than the pilot symbol is detected. In the communication device on the receiving side that performs control,
Pilot reception error detection means for detecting a reception error of the pilot symbol based on a known pilot symbol pattern;
In addition to transmission power control based on the comparison result of the reception quality, transmission power control means for performing transmission power control based on the detection result of the reception error of the pilot symbol,
A communication apparatus comprising: The transmission power control means includes
When a plurality of pilot symbols are received during one cycle of the inner loop transmission power control and the number of reception errors of the pilot symbols exceeds a specific ratio, transmission power control is performed to increase transmission power. The communication apparatus according to claim 1, wherein reception error detection of the symbol is delayed. The transmission power control means includes
When a single pilot symbol is received during one cycle of the inner loop transmission power control and a reception error of the pilot symbol is detected, transmission power control is performed to increase the transmission power, and symbols other than the pilot symbols are transmitted. The communication apparatus according to claim 1, wherein reception error detection is delayed. A first inverse modulation means for inversely modulating the pilot symbol;
Second demodulating means for demodulating the TPC symbol in the received symbol at all possible signal points;
Adding means for adding the pilot symbols after the inverse modulation to the TPC symbols after the inverse modulation;
A determination means for obtaining a signal amplitude of each addition result and performing a maximum likelihood determination using the signal amplitude as a likelihood;
Selection means for selecting a despread TPC symbol to be used for reception quality measurement based on the determination result;
With
The transmission power control is performed based on a comparison result between a reception quality measurement result obtained using the pilot symbol and the selected TPC symbol and the reception quality target value. Or the communication apparatus of 3. In addition, for each pass,
First inverse modulation means for inversely modulating the pilot symbols;
Second demodulating means for demodulating the TPC symbol in the received symbol at all possible signal points;
Adding means for adding the pilot symbols after the inverse modulation to the TPC symbols after the inverse modulation;
A phase compensation unit that uses a first path in the pilot symbol as a reference path, estimates a phase difference between the reference path and the pilot symbol, and performs phase compensation on each addition result based on the estimation result;
With
further,
Phase-compensated signal addition means for adding each signal after phase compensation output individually for each path for each assumed signal point;
A determination means for obtaining a signal amplitude of each addition result of the phase-compensated signal and performing a maximum likelihood determination using the signal amplitude as a likelihood;
Selection means for selecting, for each path, a despread TPC symbol used for reception quality measurement based on the determination result;
With
The transmission power control is performed based on a comparison result between a reception quality measurement result obtained using the pilot symbol and the selected TPC symbol and the reception quality target value. Or the communication apparatus of 3. The communication apparatus according to claim 4 or 5, wherein when a pilot symbol and a TPC symbol that are reception quality measurement targets are separated in time, phase fluctuation due to fading is compensated.

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