JP2012143001A - Communication control method for wireless communication system, terminal device for wireless communication system and base station device for wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve transmission characteristics of ACK/NACK (reception result confirmation information).SOLUTION: Based on first reception result confirmation information transmitted to a base station device and signals received after from the base station device, a terminal device 5 determines whether the base station device incorrectly received the first reception result confirmation information. When it is determined that the base station device incorrectly received the first reception result confirmation information, the terminal device 5 performs control to increase transmission power of second reception result confirmation information to be transmitted to the base station device, meanwhile, when the transmission power reaches an upper limit, changes a transmission method of the second reception result confirmation information to a transmission method improving transmission characteristics of the second reception result confirmation information.

Description

  The present invention relates to a communication control method for a wireless communication system and a wireless reception device. For example, the present invention is suitable for use in a system that stipulates that an ACK (no error) / NACK (with error) signal is returned to the transmission side for received data.

(1) Retransmission control and ACK / NACK transmission power control Currently, the 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) system, which is the next generation mobile communication system for which specifications are being studied, and services in Japan In the started HSDPA (High Speed Downlink Packet Access) system and the HSUPA (High Speed Uplink Packet Access) system that is expected to start the service in the future, a packet retransmission control function is defined.

Hereinafter, retransmission control will be described.
On the transmission side (for example, a radio base station), CRC is added to transmission data, encoded, modulated, and then converted (up-converted) to a radio frequency and transmitted from the antenna to the reception side.
On the receiving side (for example, a wireless terminal), the signal received by the antenna is demodulated, and decoding is performed using the demodulation result. Then, the CRC of the decoding result is confirmed to determine whether there is an error.

  If there is no error in the received signal as a result of the discrimination, an ACK (Acknowledgement) signal, which is a signal indicating that the signal has been received without error, is generated as reception result confirmation information, and the ACK signal is returned to the transmitting side. On the other hand, if there is an error, a NACK (Not Acknowledgement) signal, which is a signal indicating that the signal has been received including the error, is generated as reception result confirmation information, and this is returned to the transmitting side. Note that the NACK signal may be described as a NAK signal.

  On the transmission side, after demodulating and decoding the received signal, the reception result confirmation information (ACK / NACK signal) is extracted. When an ACK signal (hereinafter simply referred to as “ACK”) is received and extracted, new data is transmitted to the receiving side, and a NACK signal (hereinafter also simply referred to as “NACK”) is received and extracted. Retransmits the corresponding transmitted data to the receiving side. Thereafter, retransmission is repeated until transmission is possible without error.

With the above retransmission control, data can be transmitted without error.
Note that the receiving side can control transmission power when transmitting ACK / NACK to the transmitting side. For example, the transmission power value is calculated on the reception side based on the control signal transmitted from the transmission side, and the gain and amplitude adjustment of the transmission signal (ACK / NACK signal) are performed on the basis of this. / NACK transmission power is controlled.

(2) Retransmission control and ACK / NACK transmission power control in the HSDPA system The HSDPA system also has a retransmission control function.
The HSDPA system is an improved version that implements a downlink high-speed packet transmission function with respect to the specification Rel'99 of the 3GPP W-CDMA system, and has been studied and specified as Rel'5 (Non-Patent Document 1, described later). 2, 3, 4).

In the HSDPA system (see FIG. 43), HS-, which is a channel for transmitting downlink data (downlink) from a radio base station (Node B) (hereinafter also referred to as BS) to a radio terminal (UE). Downlink dedicated physical channel (A-DPCH) that transmits DSCH (High Speed-Downlink Shared CHannel) and accompanying data and control signals (pilot signal, transmission power control (TPC) signal, etc.) And the uplink dedicated physical channel (DPCH: Dedicated Physical CHannel) from the UE to the BS. Also, data and control signals (eg, dedicated pilot signals and transmission power control (TPC) signals) are transmitted from the UE to the BS using the DPCH (see Non-Patent Documents 1, 2, 3, and 4).
The DPCH accompanied by the HS-DSCH is called a downlink A-DPCH, and there is a downlink DPCH not accompanied by the HS-DSCH. The DPCH includes a DPDCH (Dedicated Physical Data CHannel) that is a radio channel for transmitting data and a DPCCH (Dedicated Physical Control CHannel) that is a radio channel for transmitting a control signal. The ACK / NACK signal can be transmitted using HS-DPCCH (High Speed-Dedicated Physical Control CHannel).

Hereinafter, retransmission control in the HSDPA system will be described.
The UE measures and calculates CQI (Channel Quality Indicator), which is an indicator of radio channel characteristics (quality), based on the received power of the pilot signal transmitted from the BS by CPICH (Common Pilot Indicator CHannel), and sets HS-DPCCH. Use to return.
The BS that has received the CQI from each UE selects the UE to be transmitted by the scheduler, determines the transmission method (data size, modulation scheme, encoding method, process number, etc.), and whether the information and the new transmission. A control signal including an index indicating retransmission is generated, and the control signal is transmitted to the UE by HS-SCCH (High Speed-Shared Control CHannel).

Subsequently, the BS selects data to be transmitted according to the determined transmission method for the UE selected by the scheduler, adds a CRC to the data, encodes, modulates, spreads, and then transmits the radio. It converts into a frequency and transmits to UE by HS-DSCH from an antenna. The HS-DSCH transmission power value at this time is a constant power offset value Γ and a power offset value Δ determined by CQI with respect to the CPICH transmission power value P _CPICH as shown in the following equation (1). The transmission power value calculated based on the above can be used (see Non-Patent Document 4 below).

In the equation (1), Γ is a value given by a control signal from a higher-level device of the BS (for example, a base station control device (RNC)).
Further, the ACK / NACK signal described above is transmitted from the UE to the BS using the HS-DPCCH. At this time, retransmission control is performed on data transmitted by HS-DSCH.

For example, the BS adds CRC to transmission data, encodes, modulates and spreads, then frequency-converts and transmits the antenna to the UE. In the UE, the received signal is converted into a baseband signal, despread and demodulated, and then decoded, and the CRC is confirmed to check for errors.
If there is no error, an ACK signal is generated, and if there is an error, a NACK signal is generated. At this time, ACK is set to +1, NACK is set to -1, and the case of not transmitting (DTX) is handled as a 1-bit control signal. Further, as shown in Table 1 below, in order to improve the transmission characteristics, this control signal is repeated, for example, 10 times to obtain a 10-bit signal at the time of encoding.

Note that uplink data, TPC, and pilot are transmitted using uplink DPCH. At this time, the transmission power of the uplink DPCH is controlled using, for example, a pilot signal transmitted on the downlink A-DPCH so that the SIR that is the ratio of the interference power and the signal power of other cells and the own cell becomes constant.
Furthermore, it is possible to perform HS-DPCCH transmission power control for performing ACK / NACK transmission using, for example, power obtained by adding 3 dB to the uplink DPCH transmission power.

Further, since the ACK signal is +1, the power is higher than the reference transmission power, and the NACK signal is -1, so the power is lower than the reference transmission power.
In the BS, the received signal is converted into a baseband signal, despread and demodulated, and then each is a soft decision signal, the above 10 signals are added, and if the addition result is positive, it is determined as ACK, If it is negative, it is determined as NACK. When the addition result is 0, it is determined as DTX. In the determination, it is preferable to perform the ACK / NACK determination with the received power and the pilot received power as the average received power in consideration of the variation of the received power due to fading or the like.

Uplink data is transmitted using the uplink DPCH. At this time, the transmission power of the uplink DPCH is controlled using, for example, a TPC signal transmitted on the downlink A-DPCH so that the SIR that is the ratio of the interference power and the signal power of other cells and the own cell is constant. Accurate power control is described in Non-Patent Document 4 below.
As described above, the uplink DPCH includes the uplink DPDCH and the uplink DPCCH, and the uplink DPDCH transmission power is defined by the uplink DPCCH transmission power (see Non-Patent Documents 3 and 4).

Here, β _c is a gain factor given from the upper level, and β _hs is a gain factor defined below.

  In order to make the equation (2) easy to understand, the equation is modified to obtain the following equation (5).

  Here, replacement is performed by the following equations (6), (7), and (8) to obtain equation (9).

  In order to pay attention to the ACK / NACK transmitted by the HS-DPCCH, the replacement by the following equation (10) is performed.

(3) Retransmission control in enhanced HSDPA system In 3GPP, an improved version of HSDPA was studied and specified as Rel6 together with HSUPA (High Speed Uplink Packet Access) and F-DPCH (Fractional-Dedicated Physical CHannel). (See Patent Documents 5, 6, 7, and 8).
This improvement is intended to reduce ACK / NACK misjudgment in the HSDPA system. For example, as shown in FIG. 44, a pre (Pre) signal before the ACK / NACK signal and a post (Post) signal after the ACK / NACK signal. Is added to reduce the occurrence of failures due to ACK / NACK misjudgment (details will be described later).

  Here, the pre-signal and the post-signal are signals obtained by combining +1 and −1 so that the addition result is −3. By using this signal, as described above, ACK / NACK is not determined based only on whether the addition result is positive or negative, but ACK / NACK is determined using pre / post signals. / NACK determination accuracy can be improved (see the following table 2).

(4) HSUPA system The HSUPA system is a system that has been studied in order to realize uplink high-speed packet communication, and is a packetized and increased speed E-DPCH (Enhanced-Dedicated Physical CHannel) of the conventional uplink DPCH (Dedicated Physical CHannel). ), E-HICH (Enhanced-HARQ Indicator CHannel) that performs ACK / NACK transmission, E-AGCH (Enhanced-Absolute Grant CHannel), and E-RGCH (Enhanced-Relative Grant CHannel) It realizes transmission. It has been studied and specified by 3GPP (see Non-Patent Documents 5, 6, 7, and 8).

(5) LTE System The LTE (Long Term Evolution) system is a system that is being studied by 3GPP as a next-generation mobile communication system, and performs packet transmission in the same way as the HSDPA system and HSUPA system. ACK / NACK transmission is performed (see Non-Patent Documents 9, 10, and 11 below).

(6) Other conventional technologies As other conventional technologies, there are technologies described in Patent Documents 1 and 2 below.
In Patent Document 1, as a method for controlling the transmission power of a base station in a wireless communication network, a step of transmitting a power control command to a mobile station with a first transmission power and a non-power control with a second transmission power A command (rate control command, retransmission control command (ACK / NAK, etc.)) is transmitted to the mobile station, and based on a determination result of whether the mobile station appropriately responded to the non-power control command And performing the step of controlling the first transmission power.

  Further, in Patent Document 2, when a response signal for communication data could not be received, it was determined that the response signal from the communication terminal could not be received for the purpose of improving the reliability of re-reception of communication data. In this case, the cause is determined, and when it is determined that the response data is not transmitted because the communication data does not reach the communication terminal, the transmission power when transmitting the communication data is increased. .

Special Table 2007-503169 JP 2006-262357 A

3GPP TS25.211 V5.8.0 3GPP TS25.212 V5.10.0 3GPP TS25.213 V5.6.0 3GPP TS25.214 V5.11.0 3GPP TS25.211 V6.7.0 3GPP TS25.212 V6.10.0 3GPP TS25.213 V6.5.0 3GPP TS25.214 V6.11.0 3GPP TS36.211 V1.0.0 3GPP TS36.212 V1.0.0 3GPP TS36.213 V1.0.0 R1-021334

As described above, transmission power control of HS-DPCCH that transmits ACK / NACK can be performed with a transmission power value obtained by adding an offset to the transmission power value of uplink DPCH. It has been found that the transmission characteristics of / NACK deteriorate and the characteristics deteriorate (see Non-Patent Document 1).
Due to this characteristic deterioration, the following failure occurs during transmission from the UE to the BS.

(A) If the BS determines NACK even though the UE has transmitted ACK, the BS performs a retransmission process. Since transmission has already been performed without error, useless transmission is performed.
(B) If the BS transmits an NACK even though the UE has transmitted an NACK, the BS performs a new transmission, data to be retransmitted is not transmitted, and data loss occurs.

(C) If the BS determines that the TX is DTX even though the UE has transmitted an ACK, the BS determines that there is no return from the UE and performs a retransmission process. As in (b), since transmission has already been performed without error, useless transmission is performed.
(D) If the BS determines that the TX is DTX even though the UE has transmitted a NACK, the BS determines that there is no return from the UE, and performs a retransmission process.

(E) When the BS determines ACK even though the UE is DTX, the BS performs new transmission, resulting in data loss.
(F) When the UE determines that the BS is NACK even though the UE is DTX, there is a possibility that the BS performs a retransmission process and wasteful transmission is performed.
The phenomena (a) to (c) become obstacles. In particular, the case (b) is a big problem because data is lost. Hereinafter, (a) to (d) are collectively described as ACK / NACK misjudgment. The phenomenon of (e) and (f) does not occur because ACK / NACK transmission is performed at regular intervals with respect to the HS-DSCH transmission timing in the current HSDPA system. However, when the ACK / NACK transmission timing is not constant, cases (e) and (f) are also included in one of the ACK / NACK misjudgments.

It has also been found that the above-mentioned failure is caused by ACK / NACK transmission power control not operating properly at the cell edge or during high-speed movement (see Non-Patent Document 12).
On the other hand, in the enhanced HSDPA system, since the pre / post signal is added to the ACK / NACK, the occurrence of the ACK / NACK misjudgment can be reduced as compared with the case where the pre / post signal is not added. Is a consideration.

(1) Increase in power consumption Since a maximum three times as many signals are transmitted as compared with an original signal not added with a pre / post signal, a maximum three times as much transmission power is required. Since the amplifier occupies a large part of the power consumption in the UE, the power consumption increases. Moreover, there is a risk that the call time and standby time may be shortened.

(2) Increase in uplink interference Since a signal having a maximum of three times is transmitted as compared with an original signal to which no pre / post signal is added, the uplink interference is simply tripled at the maximum. Therefore, transmission characteristics of other UEs are degraded.
Therefore, one of the objects of the present invention is to improve the transmission characteristics of ACK / NACK (reception result confirmation information). Note that Patent Documents 1 and 2 do not disclose or suggest the point of improving the transmission characteristics of ACK / NACK.

It is also an object of the present invention to reduce the occurrence rate of ACK / NACK misjudgment.
Furthermore, it is one of the objects of the present invention to keep the interference power low.
In addition, the present invention is not limited to the above-described object, and is an operational effect derived from each configuration shown in the best mode for carrying out the invention described later, and has an operational effect that cannot be obtained by conventional techniques. Can be positioned as one of the purposes.

  (1) As a first proposal, for example, a base station apparatus and a terminal apparatus that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the base station apparatus to the base station apparatus are provided. In the communication control method for a wireless communication system, the terminal device performs the base station based on first reception result confirmation information transmitted to the base station device and a signal received thereafter from the base station device. When the station apparatus determines whether or not the first reception result confirmation information has been received in error, and determines that the base station apparatus has received the first reception result confirmation information in error, the base station apparatus While the transmission power of the second reception result confirmation information to be transmitted is controlled to increase, when the transmission power reaches the upper limit, the second reception result confirmation information transmission method is changed to the transmission of the second reception result confirmation information. Transmission method with improved characteristics To change, it is possible to use a communication control method for a wireless communication system.

  (2) As a second proposal, for example, a radio including a terminal device and a base station device that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the terminal device to the terminal device A communication control method for a communication system, wherein the base station device is configured so that, based on first reception result confirmation information transmitted to the terminal device and a signal received from the terminal device thereafter, the terminal device It is determined whether or not the first reception result confirmation information has been received in error, and if it is determined that the terminal device has received the first reception result confirmation information in error, the second reception to be transmitted to the terminal device While the transmission power of the result confirmation information is controlled to increase, when the transmission power reaches the upper limit, the transmission method of the second reception result confirmation information is improved when the transmission method of the second reception result confirmation information is improved. Change to method It can be used to communicate control method of a wireless communication system.

  (3) As a third proposal, for example, a base station apparatus and a terminal apparatus that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the base station apparatus to the base station apparatus are provided. The terminal device of the wireless communication system, wherein the base station device performs the first reception result confirmation information transmitted to the base station device and the signal received from the base station device thereafter. Determining means for determining whether or not the reception result confirmation information of 1 has been received in error, and determining that the base station apparatus has erroneously received the first reception result confirmation information by the determination means; While the transmission power of the second reception result confirmation information transmitted to the base station apparatus is increased and controlled, when the transmission power reaches the upper limit, the second reception result confirmation information transmission method is changed to the second reception result confirmation information. Confirmation information transmission characteristics And a control means for changing the transmission method to be, equipped with, can be used terminal device of a wireless communication system.

  (4) As a fourth proposal, for example, a radio including a terminal device and a base station device that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the terminal device to the terminal device The base station apparatus of the communication system, wherein the terminal apparatus receives the first reception result based on first reception result confirmation information transmitted to the terminal apparatus and a signal received thereafter from the terminal apparatus. A determination unit that determines whether or not confirmation information has been received in error, and a transmission to the terminal device when the determination unit determines that the terminal device has received the first reception result confirmation information in error. While the transmission power of the second reception result confirmation information is increased and controlled, when the transmission power reaches the upper limit, the transmission method of the second reception result confirmation information is changed according to the transmission characteristic of the second reception result confirmation information. Improved transmission And a control means for changing the law, equipped with, can be used a base station device of a wireless communication system.

  According to the present invention, it is possible to improve transmission characteristics when transmitting reception result confirmation information to a wireless transmission device. As a result, it is possible to reduce the occurrence rate of reception errors (incorrect determination) of reception result confirmation information in the wireless transmission device. Further, the throughput from the wireless transmission device to the wireless reception device can be improved.

1 is a block diagram showing a configuration of a radio base station (BS) according to a first embodiment of the present invention. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 1st Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 1st embodiment. It is a block diagram which shows the structure of the wireless base station (BS) which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 2nd Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 2nd embodiment. It is a block diagram which shows the structure of the wireless base station (BS) which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 3rd Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 3rd embodiment. It is a block diagram which shows the structure of the wireless base station (BS) which concerns on 4th Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 4th embodiment. It is a block diagram which shows the structure of the wireless base station (BS) which concerns on 5th Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 5th embodiment. It is a flowchart explaining ACK / NACK transmission power control (correction) concerning a 5th embodiment. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 6th Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 6th embodiment. It is a flowchart explaining the ACK / NACK transmission power control (correction | amendment) based on 6th Embodiment. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 7th Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 7th embodiment. It is a flowchart explaining the ACK / NACK transmission power control (correction | amendment) based on 7th Embodiment. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 8th Embodiment of this invention. It is a flowchart explaining operation | movement of MS shown in FIG. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 9th Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 9th embodiment. It is a flowchart explaining the ACK / NACK transmission power control (correction | amendment) based on 9th Embodiment. It is a figure explaining ACK / NACK transmission power control (correction) concerning a 10th embodiment of the present invention. It is a figure explaining another aspect of ACK / NACK transmission power control (correction) concerning a 10th embodiment. It is a figure explaining another aspect of ACK / NACK transmission power control (correction) concerning a 10th embodiment. It is a figure explaining another aspect of ACK / NACK transmission power control (correction) concerning a 10th embodiment. It is a block diagram which shows the structure of the wireless base station (BS) based on 11th Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning an 11th embodiment. It is a flowchart explaining the ACK / NACK transmission power control (correction | amendment) based on 11th Embodiment. It is a figure explaining ACK / NACK transmission power control (correction) concerning a 12th embodiment of the present invention. It is a figure explaining another aspect of ACK / NACK transmission power control (correction) concerning a 12th embodiment. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 14th Embodiment of this invention. It is a block diagram of a HSUPA system. It is a block diagram which shows the structure of the wireless base station (BS) which concerns on 15th Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless terminal (UE) which concerns on 15th Embodiment of this invention. It is a sequence diagram explaining ACK / NACK transmission power control (correction) concerning a 15th embodiment. It is a block diagram which shows the structure of the wireless base station (BS) based on 16th Embodiment of this invention. It is a block diagram which shows the structure of the wireless base station (BS) based on 18th Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless terminal (UE) based on 18th Embodiment of this invention. It is a block diagram of a HSDPA system. It is a figure which shows the format of the ACK / NACK signal in an enhanced HSDPA system.

Embodiments of the present invention will be described below with reference to the drawings. However, it goes without saying that the present invention is not limited to the embodiments described below, and can be implemented with various modifications without departing from the spirit of the present invention. For example, combinations of the embodiments not explicitly described below can be performed.
[1] First Embodiment FIG. 1 is a block diagram showing a configuration of a radio base station (BS) according to the first embodiment of the present invention, and FIG. 2 is a radio terminal (UE) according to the first embodiment of the present invention. ), The radio communication system is configured by the BS 1 shown in FIG. 1 and the UE 5 shown in FIG.

In the wireless communication system, there may be a plurality of BS1 and UE2. The wireless communication system may be any of various mobile communication systems such as an HSDPA system, an HSUPA system, an HSPA system in which the HSDPA system and the HSUPA system are integrated, and an LTE system.
Further, when focusing attention on downlink communication, BS1 is positioned as a wireless transmission device, and UE5 is positioned as a wireless reception device. Conversely, if attention is paid to uplink communication, UE 5 is positioned as a wireless transmission device and BS 1 is positioned as a wireless reception device (hereinafter the same).

(Description of BS1)
1 includes, for example, a transmission buffer 10, an encoding unit 11, a modulation unit 12, a transmission radio unit 13, an antenna 14, a reception radio unit 15, a demodulation unit 16, and a decoding unit 17. , An ACK / NACK extraction unit 18 and a retransmission control unit 19 are provided.
Here, the transmission buffer 10 buffers data and control signals to be transmitted to the UE 5, and the encoding unit 11 performs predetermined encoding (error correction code) on the data and control signals from the transmission buffer 10. Encoding).

The modulation unit 12 modulates the signal encoded by the encoding unit 11 with a predetermined modulation method (for example, QPSK, 16QAM, etc.), and the transmission radio unit 13 is modulated by the modulation unit 12. The signal is subjected to predetermined transmission radio processing such as DA conversion, frequency conversion to radio frequency (up-conversion), and power amplification to transmission power.
The antenna 14 transmits the radio signal obtained by the transmission radio unit 13 toward the UE 5, and receives the radio signal transmitted from the UE 5 and outputs the radio signal to the reception radio unit 15.

  The reception radio unit 15 performs predetermined reception radio processing such as low noise amplification, frequency conversion to a baseband signal (down-conversion), AD conversion, and the like on the signal received by the antenna 14. 16 demodulates the reception signal after the reception radio processing by a demodulation method corresponding to the modulation method at the transmission side (UE5), and the decoding unit 17 transmits the reception signal demodulated by the demodulation unit 16 to the transmission side. The decoding is performed by a decoding method corresponding to the encoding method in (UE5).

The ACK / NACK extraction unit 18 extracts (detects) an ACK signal or a NACK signal from the decoding result obtained by the decoding unit 17.
When receiving an ACK signal from the ACK / NACK extraction unit 18, the retransmission control unit 19 inputs new data addressed to the UE 5 to the encoding unit 11 to transmit from the antenna 14, and when receiving a NACK signal The transmission buffer 10 is controlled so that the transmitted data held in the transmission buffer 10 is input from the antenna 14 to the encoding unit 11 to be retransmitted.

(Description of UE5)
On the other hand, the UE 5 illustrated in FIG. 2 includes, for example, an antenna 51, a reception radio unit 52, a demodulation unit 53, a decoding unit 54, a control signal extraction unit 55, an ACK / NACK erroneous determination detection unit 56, and transmission power. A control unit 57, an ACK / NACK signal generation unit 58, a retransmission control unit 58a, an error detection unit 58b, an encoding unit 59, a modulation unit 60, and a transmission radio unit 61 are provided.

Here, the antenna 51 receives the radio signal transmitted from the BS 1 and outputs it to the reception radio unit 52, while transmitting the radio signal obtained by the transmission radio unit 61 toward the BS 1.
The reception radio unit 52 performs predetermined reception radio processing such as low noise amplification, frequency conversion to a baseband signal (down-conversion), and AD conversion on the reception radio signal from the antenna 51.

The demodulator 53 demodulates the received signal after the reception radio processing by a demodulation method corresponding to the modulation method on the transmission side (BS1).
The decoding unit 54 decodes the reception signal demodulated by the demodulation unit 53 by a decoding method corresponding to the encoding method on the transmission side (BS1).
The control signal extraction unit 55 extracts a control signal from the decoding result by the decoding unit 54.

The error detection unit 58b detects the presence or absence of an error in the received data by confirming the CRC of the received data decoded by the decoding unit 54 (CRC calculation).

The ACK / NACK signal generation unit 58 determines OK if the detection result (CRC calculation result) by the error detection unit 58b has no error, and determines ACK if there is an error, and generates NACK by determining NG. .

  The ACK / NACK misjudgment detection unit (determination unit) 56 cooperates with the retransmission control unit 58a to transmit the ACK / NACK (first reception confirmation result information) transmitted to BS1 and the signal received from BS1 thereafter ( Based on the downlink data and the control signal extracted by the control signal extraction unit 55), it is detected (determination) whether BS1 has erroneously received the ACK / NACK (whether an ACK / NACK misjudgment has occurred) )

  Preferably, ACK / NACK information transmitted to BS1, number information (process number) added to downlink reception data, and information indicating whether the downlink reception data is due to new transmission or retransmission from BS1 Based on the above, the presence / absence of the ACK / NACK misjudgment is determined. That is, if UE5 has transmitted NACK (ACK) to BS1, but the downlink data of the same process number received from BS1 is due to “new transmission” (“retransmission”), UE5 has received NACK from BS1. It is determined that (ACK) is erroneously determined as ACK (NACK).

Whether the downlink received data is newly transmitted or retransmitted can be determined by (1) comparing the previously received downlink data with the currently received downlink data, or (2) transmitted accompanying the downlink data. The determination can also be made based on a control signal (NDI: New Data Indicator) indicating new transmission or retransmission.
In the former case (1), the UE 5 stores the ACK / NACK information transmitted to the BS 1 with respect to certain received data and the received data in association with the received data. In the latter case (2), the ACK / NACK information transmitted to BS 1 and the process number are associated with each other and stored in a memory or the like instead of the received data. The memory may be provided in the retransmission control unit 58a, for example, or may be provided separately from the retransmission control unit 58a (the same applies hereinafter).

Then, the ACK / NACK misjudgment detection unit 56 confirms the relationship between the ACK / NACK information stored in the memory, the information (NDI) indicating whether it is new transmission or retransmission, and the process number, and the UE 5 in the BS 1 It is confirmed whether or not the ACK / NACK transmitted is correctly determined.
For example, if ACK is stored in the memory, NDI indicates retransmission, and the received data or process number is the same as the received data or process number stored in the memory, UE5 has transmitted ACK. First, BS1 determines that it is NACK and retransmits the same data.

Conversely, if NACK is stored in the memory, NDI indicates a new transmission, and the received data or process number is the same as the received data or process number stored in the memory, UE5 has transmitted NACK. Nevertheless, BS1 determines that it is ACK and has transmitted new data.
Thus, the ACK / NACK misjudgment detection part 56 detects the ACK / NACK misjudgment in BS1 of ACK / NACK which UE5 transmitted.

  The retransmission control unit 58a controls transmission (retransmission processing) of an ACK / NACK signal to the BS1. The retransmission control unit 58a controls the transmission power of the ACK / NACK signal when the ACK / NACK erroneous determination detection unit 56 detects the ACK / NACK erroneous determination (for example, the transmission power value of the ACK / NACK). And a transmission power correction value). The obtained control information is given to the transmission power control unit 57.

However, the function may be included in the transmission power control unit 57. The retransmission control unit 58a and the transmission power control unit 57 may be configured as a functionally single control unit (the same applies hereinafter).
The transmission power control unit 57 cooperates with the retransmission control unit 58a to control the transmission radio unit 61 to transmit to the BS 1 when the ACK / NACK error determination detection unit 56 detects an ACK / NACK error determination. It controls transmission power, which is one of the conditions. In this example, when the ACK / NACK misjudgment is detected, the transmission power of ACK / NACK is controlled to increase. The transmission power control is performed, for example, by adjusting the gain and signal amplitude of a power amplifier (not shown) of the transmission radio unit 61.

The encoding unit 59 encodes an uplink signal to BS1 (transmission data addressed to BS1, an ACK / NACK signal, etc.) using a predetermined encoding method.
The modulation unit 60 modulates the uplink signal encoded by the encoding unit 59 using a predetermined modulation method (QPSK, 16QAM, etc.).
The transmission radio unit 61 performs predetermined transmission radio processing such as DA conversion, frequency conversion to radio frequency (up-conversion), and power amplification to transmission power on the modulated uplink signal.

(Description of operation)
The operation (ACK / NACK transmission power control) of the wireless communication system configured as described above will be described below with reference to the sequence diagram shown in FIG.
In BS1 on the transmission side, the encoding unit 11 encodes the transmission data to which the CRC addressed to UE5 is added and the control signal and pilot signal (control signal) to which the CRC is added, and the encoding result is modulated. After being modulated by the unit 12, the transmission radio unit 13 performs the predetermined radio transmission process and transmits the antenna 14 to the UE 5 (steps S1 and S2).

On the other hand, in the UE 5 on the receiving side, a signal received by the antenna 51 is subjected to the predetermined reception radio processing by the reception radio unit 52 and converted into a baseband signal, and then demodulated by the demodulation unit 53. The decryption unit 54 decrypts the data.
The decoding result is input to the control signal extraction unit 55 and the error detection unit 58b, and the error detection unit 58b confirms the CRC of the decoding result and confirms whether there is an error in the received data (step S3). As a result, if there is no error in the received data, the ACK / NACK signal generation unit 58 generates an ACK signal, and if there is an error, generates an NACK signal.

On the other hand, in the control signal extraction unit 55, a control signal is extracted from the decoding result, and the transmission power control unit 57 calculates (determines the transmission power value P _t-1 of the ACK / NACK signal to BS1 based on the control signal. (Step S4).
Then, the transmission power of the ACK / NACK signal generated by the ACK / NACK signal generation unit 58 is adjusted by adjusting the amplifier gain and signal amplitude of the transmission radio unit 61 based on the transmission power value P _t−1. Be controlled.

That is, the ACK / NACK signal generated by the ACK / NACK signal generation unit 58 is encoded by the encoding unit 59, modulated by the modulation unit 60, and then transmitted by the transmission radio unit 61. The processed signal is transmitted to the BS 1 via the antenna 51 at the transmission power value P _t−1 (step S5).
BS 1 receives the ACK / NACK signal transmitted by UE 5 at antenna 14, performs the predetermined reception radio processing at reception radio unit 15, demodulates at demodulation unit 16, and decodes at decoding unit 17. (Step S6).

The decoding result is input to the ACK / NACK extraction unit 18, the ACK / NACK extraction unit 18 extracts the ACK / NACK signal, and the extraction result (ACK or NACK) is transmitted to the retransmission control unit 19. .
If the extraction result is ACK, the retransmission control unit 19 reads the control signal (pilot signal) and the new data from the transmission buffer 10 and inputs them to the encoding unit 11, thereby transmitting the pilot signal and the new data to the UE 5. To send to. If it is NACK, the control signal (pilot signal) and the previous transmission data (retransmission data) are read from the transmission buffer 10 and input to the encoding unit 11 to transmit the pilot signal and the retransmission data to the UE 5. (Steps S7 and S8).

  Further, the UE 5 receives the pilot signal and data (new or retransmitted data) transmitted from the BS 1 with the antenna 51, performs the predetermined reception radio processing with the reception radio unit 52, and converts it into a baseband signal Thereafter, the signal is demodulated by the demodulator 53 and decoded by the decoder 54. The decoding result is input to the control signal extraction unit 55 and the error detection unit 58b, and the control signal extraction unit 55 extracts a control signal (process number, NDI, etc.) from the decoding result and detects ACK / NACK error determination. Transmitted to the unit 56.

As described above, the ACK / NACK misjudgment detection unit 56 confirms the relationship between the ACK / NACK information transmitted to the BS1 last time, the NDI, and the data or process number stored in the memory. It is confirmed whether ACK / NACK is correctly determined (step S9).
For example, if ACK was sent to BS1 last time, the received NDI from BS1 indicates retransmission, and the received data or its process number is the same as the previous received data or process number, UE5 sent ACK. Nevertheless, BS1 determines that it is NACK and retransmits the same data.

Conversely, if the last transmission is NACK and the received NDI indicates a new transmission, and the received data or its process number is the same as the previous received data or process number, the UE 5 has transmitted a NACK. BS1 determines that ACK has been transmitted and has transmitted new data.
If it is determined that such an ACK / NACK misjudgment has occurred, the ACK / NACK misjudgment detection unit 56 notifies the retransmission control unit 58a of the occurrence of an ACK / NACK misjudgment. Receiving this notification, the retransmission control unit 58a corrects the transmission power value P _t-1 at the previous ACK / NACK transmission (step S5) to obtain the current ACK / NACK transmission power value P _t (step S10). .

For example, the transmission power value P _t of the current ACK / NACK generated by the ACK / NACK signal generation unit 58 is based on the previous ACK / NACK transmission power value P _t−1 (at the time of new transmission and at the first retransmission). Also make it bigger. At this time, it is preferable to perform control so that the influence of interference due to an increase in transmission power is allowed and the ACK / NACK transmission characteristics are improved. For example, it is increased in 0.5 dB steps. However, different step widths may be used for ACK transmission and NACK transmission.

  Further, the reduction control can be performed according to either ACK or NACK. For example, when NACK is erroneously determined to be ACK at BS1, reception data loss occurs. Therefore, if this is avoided as much as possible, control is performed to increase the transmission power value of NACK and decrease the transmission power value of ACK. Is possible. On the contrary, if ACK is erroneously determined as NACK in BS1, unnecessary transmission is performed from BS1, so if this is avoided as much as possible, the transmission power value of ACK is increased and the transmission power of NACK is increased. The value can be controlled to decrease.

Further, after such ACK / NACK transmission power control is performed, if an ACK / NACK misjudgment is detected again (ACK / NACK transmission characteristics are not improved), as described later in the nineteenth embodiment. The current transmission power value can also be controlled with a larger control amount than the control amount (step width) of the previous transmission power value.
The ACK / NACK transmission power value can be expressed as an offset value (control amount) with respect to the transmission power value of the uplink data channel (DPCH). In this case, the transmission power control unit 57 can control the ACK / NACK transmission power value (HS-DPCCH transmission power value) by controlling the offset value. Also, it is possible to indirectly control the ACK / NACK transmission power value by controlling the transmission power value of the uplink DPCH. However, it is also possible to directly control the transmission power value of HS-DPCCH used for ACK / NACK transmission without using an offset value. These points are the same in the following description.

The offset value is preferably calculated in BS1 by using a pilot signal transmitted from a plurality of UEs 5 at a certain time, ACK / NACK, DPCH transmission characteristics (for example, CIR and SIR), etc. An offset value (in a range in which the influence of the interference is allowed) where the interference is equal to or less than the threshold is calculated, and notified to each UE 5 in advance.
That is, the transmission power control of ACK / NACK in UE 5 may be performed based on the transmission power value or transmission power correction value calculated by UE 5, or the transmission power value or transmission power correction value calculated by BS 1 is set to UE 5 May be implemented by receiving (the same applies to the following description).

Retransmission control section 58a as described above, obtains the ACK / NACK transmission power value P _t, and notifies the transmission power control unit 57. Transmission power control unit 57, by adjusting the amplifier gain and the signal amplitude of the transmission radio unit 61 based on the notified ACK / NACK transmission power value P _t, this time generated by the ACK / NACK signal generating unit 58 Controls the transmission power of the ACK / NACK signal to be transmitted (returned) to BS1.

That is, the ACK / NACK signal generated by the ACK / NACK signal generation unit 58 is encoded by the encoding unit 59, modulated by the modulation unit 60, and then transmitted by the transmission radio unit 61. The processed signal is transmitted to the BS 1 via the antenna 51 at the transmission power value P _t (step S11) and received by the BS 1 (step S12).
In the example shown in FIG. 16, the ACK / NACK transmission power is calculated (step S4) after the first data transmission (actually new transmission: step S2), and after confirming the presence or absence of error by CRC (step S3). However, the detection process by the ACK / NACK misjudgment detection unit 56 may be performed between both (step S3 and step S4). However, since it is a new transmission, it is determined that there is no erroneous determination.

As described above, according to the present embodiment, when an ACK / NACK misjudgment is detected, the transmission power of the ACK / NACK is controlled, so that the ACK / NACK transmission characteristics are improved and an ACK / NACK misjudgment occurs. The rate can be reduced, which can improve the throughput.
In the above-described embodiment, ACK / NACK transmission characteristics are improved by controlling transmission power that is one of ACK / NACK transmission conditions. By including a transmission method such as a coding rate, the ACK / NACK transmission characteristics are improved by controlling (decreasing) the multi-level number of the modulation scheme or controlling (decreasing) the coding rate. You may do it. This function may be shared with the transmission power control unit 57 of the UE 5, or may be individually provided in the UE 5 as a transmission method control unit. These points are the same in the embodiments described below.

  Further, in the following description of the embodiment, as an example of ACK / NACK misjudgment, when BS1 interprets ACK as NACK, conversely, it may refer only to either one when NACK is interpreted as ACK. This does not mean that only one of them can be handled. Unless otherwise noted, all of the ACK / NACK misjudgments described above can be handled.

[2] Second Embodiment (Application to HSDPA system)
FIG. 4 is a block diagram showing a configuration of a radio base station (BS) according to the second embodiment of the present invention, and FIG. 5 is a block diagram showing a configuration of a radio terminal (UE) according to the second embodiment of the present invention. Thus, the BS 1 shown in FIG. 4 and the UE 5 shown in FIG. 5 constitute a radio communication system, here an HSDPA system. Also in this example, there may be a plurality of BS1 and UE2 respectively.

(Description of BS)
4 includes, for example, a transmission buffer 10, an encoding unit 11, a modulation unit 12, a spreading unit 12a, a transmission radio unit 13, an antenna 14, a reception radio unit 15, and a despreading unit 16a. A demodulator 16, a decoder 17, an ACK / NACK extractor 18, a retransmission controller 19, a scheduler 20, a control signal generator 21, a CQI extractor 22, and an uplink pilot power calculator 24. The transmission power control unit 25 is provided.

  Here, the transmission buffer 10 buffers transmission data addressed to the UE 5, and the encoding unit 11 transmits the transmission data addressed to the UE 5 and the control signal generated by the control signal generation unit 21 (pilot signal, process number, NDI, TPC signal, etc.) are encoded by a predetermined encoding (error correction encoding) method. The control signal here includes a control signal related to transmission of HS-DSCH, and is transmitted using HS-SCCH. Further, the pilot signal includes a downlink common pilot signal and a downlink dedicated pilot signal. The downlink common pilot signal is transmitted using CPICH, and the downlink dedicated pilot signal is transmitted using DPCH.

The modulation unit 12 modulates the signal encoded by the encoding unit 12 with a predetermined modulation method (for example, QPSK, 16QAM, etc.).
The spreading unit 12a spreads the signal modulated by the modulating unit 12 using a predetermined spreading code.
The transmission radio unit 13 performs predetermined transmission radio processing such as DA conversion, frequency conversion (up-conversion) to radio frequency, power amplification to transmission power, etc. on the signal spread by the spreading unit 12a. is there.

The antenna 14 transmits the radio signal obtained by the transmission radio unit 13 toward the UE 5, and receives the radio signal transmitted from the UE 5 and outputs the radio signal to the reception radio unit 15.
The reception radio unit 15 performs predetermined reception radio processing such as low noise amplification, frequency conversion (down-conversion) to a baseband signal, and AD conversion on the signal received by the antenna 14.

The despreading unit 16a despreads the received signal subjected to the reception radio processing using a replica of the predetermined spreading code.
The demodulator 16 demodulates the received signal after despreading by a demodulation method corresponding to the modulation method on the transmission side (UE5).
The decoding unit 17 decodes the reception signal demodulated by the demodulation unit 16 with a decoding method corresponding to the encoding method on the transmission side (UE 5).

The ACK / NACK extraction unit 18 extracts the ACK / NACK signal transmitted from the UE 5 from the decoding result obtained by the decoding unit 17.
The retransmission control unit 19 controls the scheduler 19 according to the extraction result (ACK or NACK) by the ACK / NACK extraction unit 18 to control transmission of new or retransmission data.

  The scheduler 20 schedules transmission of downlink signals (transmission data, control signals) addressed to the UE 5. That is, based on the control from the retransmission control unit 19 and the CQI extracted by the CQI extraction unit 22, the control signal generation unit 21 controls the generation of the control signal and the data transmission conditions (data size, modulation method, A coding method, a coding rate, a process number, and the like are determined, and in response to the determination, reading of data addressed to the selected UE 5 from the transmission buffer 10 and coding parameters (coding method, coding in the coding unit 11) are performed. Rate) and the modulation method in the modulation unit 12.

The control signal generation unit 21 generates a control signal (pilot signal, process number, NDI, TPC signal, etc.) addressed to the UE 5 under the control of the scheduler 20 and the transmission power control unit 25.
The CQI extraction unit 22 extracts the CQI transmitted by the UE 5 from the decoding result obtained by the decoding unit 17. The extracted CQI is transmitted to the scheduler 20, and the coding parameter is controlled by the scheduler 20 according to the CQI.

The uplink pilot power calculation unit 24 measures (calculates) reception power of a pilot signal component (a pilot signal transmitted on the uplink DPCH) as a result of despreading by the despreading unit 16a. The obtained received power value is transmitted to the transmission power control unit 25, and downlink transmission power control based on the received power value is performed by the transmission power control unit 25.
The transmission power control unit 25 controls downlink transmission power by controlling the amplifier gain and signal amplitude in the transmission radio unit 13. For example, downlink transmission power control is performed according to a transmission power control signal from a higher-level device such as an RNC based on the reception power value obtained by the uplink pilot power calculation unit 24.

(Description of UE)
On the other hand, the UE 5 illustrated in FIG. 5 includes, for example, an antenna 51, a reception radio unit 52, a despreading unit 53a, a demodulation unit 53, a decoding unit 54, a control signal extraction unit 55, and an ACK / NACK erroneous determination detection. Unit 56, transmission power control unit 57, ACK / NACK signal generation unit 58, retransmission control unit 58a, error detection unit 58b, encoding unit 59, modulation unit 60, spreading unit 60a, and transmission radio A unit 61, a CQI measurement unit 62, and a CQI signal generation unit 63 are provided.

Here, the antenna 51 receives the radio signal (downlink signal) transmitted from the BS1 and outputs it to the reception radio unit 52, while the radio signal (uplink signal) obtained by the transmission radio unit 61 is directed to the BS1. To be sent.
The reception radio unit 52 performs predetermined reception radio processing such as low noise amplification, frequency conversion to a baseband signal (down-conversion), and AD conversion on the reception radio signal from the antenna 51.

The despreading unit 53a despreads the received downlink signal from the reception radio unit 52 using a spread code replica used on the BS1 side.
The demodulator 53 demodulates the received signal after despreading by a demodulation method corresponding to the modulation method on the transmission side (BS1).
The decoding unit 54 decodes the reception signal demodulated by the demodulation unit 53 by a decoding method corresponding to the encoding method on the transmission side (BS1).

The control signal extraction unit 55 extracts a control signal from the decoding result by the decoding unit 54.
The error detection unit 58b detects the presence or absence of errors in the received data by confirming the CRC of the received data decoded by the decoding unit 54 (CRC operation), as in the first embodiment.

The ACK / NACK erroneous determination detection unit 56 has a function of detecting that an erroneous determination of ACK / NACK has occurred in the BS 1 using the same determination method as in the first embodiment.
Similarly to the first embodiment, the transmission power control unit 57 cooperates with the retransmission control unit 58a to control the transmission radio unit 61 based on the detection result of the ACK / NACK erroneous determination detection unit 56 and to BS1. ACK / NACK transmission power is controlled. The transmission power control is performed, for example, by adjusting the gain and signal amplitude of a power amplifier (not shown) of the transmission radio unit 61.

  The retransmission control unit 58a controls transmission (retransmission processing) of an ACK / NACK signal to the BS1, and an ACK / NACK erroneous determination detection unit 56 detects an ACK / NACK erroneous determination as in the first embodiment. A function for obtaining (calculating) information (for example, transmission power value or transmission power correction value of ACK / NACK) for controlling transmission power of the ACK / NACK signal.

The ACK / NACK signal generation unit 58 confirms the CRC of the decoding result by the decoding unit 54, and determines that it is OK and ACK if there is no error and NG if there is an error and generates NACK It is.
The encoding unit 59 encodes an uplink signal to BS1 (transmission data addressed to BS1, ACK / NACK, etc.) using a predetermined encoding method.

The modulation unit 60 modulates the uplink signal encoded by the encoding unit 59 using a predetermined modulation method (QPSK, 16QAM, etc.).
The spreading unit 60a spreads the upstream encoded signal from the encoding unit 59 with a predetermined spreading code.
The transmission radio unit 61 performs predetermined transmission radio processing such as DA conversion, frequency conversion to radio frequency (up-conversion), and power amplification to transmission power on the modulated uplink signal.

The CQI measuring unit 62 measures downlink reception quality information (CQI) based on the downlink common pilot signal (CPICH) component of the despreading result by the despreading unit 53a.
The CQI signal generation unit 63 generates a CQI value to be reported to the BS 1 from the measurement result of the CQI measurement unit 62.
(Description of operation)
Hereinafter, the operation (ACK / NACK transmission power control) of the HSDPA system configured as described above will be described with reference to the sequence diagram shown in FIG.

In the HSDPA system, downlink high-speed packet transmission is performed using HS-DSCH (High Speed-Downlink Shared CHannel) which is a downlink data channel for transmitting data from BS1 (Node B) to UE5. Consider a case where packet transmission is performed for a certain UE 5 using HS-DSCH.
First, in BS 1, a common pilot signal (control signal) is generated by the control signal generation unit 21, modulated by the modulation unit 12, spread using a predetermined spreading code by the spreading unit 12 a, and the transmission radio unit 13. Then, the transmission radio processing is performed to adjust the transmission power, and the antenna 14 transmits the signal as a common pilot channel (CPICH) signal to the UE 5 (step S21). Note that the CPICH transmission power is constant.

  The UE 5 that has received this CPICH signal performs predetermined reception radio processing including down-conversion to a baseband signal on the CPICH signal, including down-conversion to a baseband signal, and the spreading used on the BS 1 side in the despreading unit 53a Despread using a replica of the code. Based on the despreading result, the CPQ signal power is measured by the CQI measuring unit 62, and the CQI, which is an index of downlink radio channel quality, is measured and calculated based on the measurement result (step S22).

  The obtained CQI is transmitted to the CQI signal generation unit 63, and the CQI signal generation unit 63 generates a CQI signal according to a predetermined uplink signal format in HSDPA. The CQI signal is encoded by the encoding unit 59, modulated by the modulation unit 60, spread by the spreading unit 60a, and then subjected to predetermined radio transmission processing by the transmission radio unit 61. It is transmitted from the antenna 51 toward BS1. At this time, the CQI signal is transmitted using an HS-DPCCH (High Speed-Dedicated Physical Control CHannel) that is an uplink dedicated control channel (step S23).

  The transmission power of this CQI signal can be a power value obtained by adding a certain offset to the transmission power value of UL-DPCH (Dedicated Physical CHannel), which is an uplink dedicated channel set together with HS-DSCH. The transmission power value of the UL-DPCH is a constant SIR of the uplink DPCH using a TPC (Transmission Power Control) signal that is a transmission power control signal transmitted on the DL-DPCH (or A-DPCH) that is the downlink dedicated channel. Is a value controlled to be

  On the other hand, the BS 1 receives the HS-DPCCH signal via the antenna 14, performs predetermined reception radio processing including down-conversion to a baseband signal in the reception radio unit 15, and despreads in the despreading unit 16 a. After spreading, demodulating by the demodulating unit 16, and decoding by the decoding unit 17, the CQI extracting unit 22 extracts the CQI and transmits the extracted CQI to the scheduler 20 (step S24).

  The scheduler 20 collects CQIs from a plurality of UEs 5 located in the service area (radio area) of the BS 1. For example, the scheduler 20 selects a target UE 5 to be transmitted in the order of CQI values, and determines a transmission method (data size, modulation scheme, encoding method, process number, etc.) to the UE 5. Further, the scheduler 20 adds an index (NDI) indicating new transmission or retransmission to the determined information (control information), and causes the control signal generation unit 21 to generate a control signal. In addition, the scheduler 20 generates a process number for the transmission data.

In the HSDPA system, HARQ (Hybrid ARQ) of a maximum 6-channel stop-and-wait method is performed, a process number (maximum 8) is defined for each HARQ, and data to be retransmitted is specified using this process number ( Identification).
The control signal is encoded by the encoding unit 11, modulated by the modulation unit 12, spread by the spreading unit 12 a, and then includes the up-conversion and transmission power adjustment by the transmission radio unit 13. Are transmitted from the antenna 14 to the UE 5 (step S25). For transmission of this control signal, HS-SCCH (High Speed-Shared Control CHannel) which is a downlink common control channel is used. The HS-SCCH transmission power value at this time is, for example, a transmission power value obtained by giving a certain offset to the downlink A-DPCH transmission power value. However, it is good also as a fixed transmission power value irrespective of UE5 which transmits.

Subsequently, the BS 1 selects transmission data for the UE 5 selected by the scheduler 20 according to the determined transmission method, reads out the transmission data addressed to the selected UE 5 from the transmission buffer 10 to the encoding unit 11, and transmits the transmission data. The encoding unit 11 adds a CRC to the encoded data.
The encoded transmission data is modulated by the modulation unit 12, spread by the spreading unit 12a, subjected to predetermined transmission radio processing by the transmission radio unit 13, and then via the antenna 14. It is transmitted toward the UE 5 as an HS-DSCH signal (step S26). The HS-DSCH transmission power value at this time is, for example, a transmission power value calculated based on a power offset value determined by a constant power offset value and CQI with respect to the downlink A-DPCH transmission power value.

  On the other hand, the UE 5 receives the HS-SCCH signal via the antenna 51, performs predetermined reception radio processing in the reception radio unit 52, despreads in the despreading unit 53a, and demodulates in the demodulation unit 53. Demodulated, decoded by the decoding unit 54, and a control signal is obtained by the control signal extraction unit 55. The UE 5 sets a reception system (reception parameters such as a demodulation method and a decoding method) according to this control signal. Further, the process number and NDI are extracted and stored in the memory or the like.

  Subsequently, the UE 5 receives the HS-DSCH signal, performs predetermined reception radio processing in the reception radio unit 52, and despreads in the despreading unit 53a based on the control information received in the HS-SCCH. The demodulator 53 demodulates the data, and the decoder 54 decodes the data. Further, the error detection unit 58b confirms whether or not there is an error with respect to the data including the header based on the added CRC (step S27).

  As a result, when there is no error, the ACK / NACK signal generator 58 generates an ACK signal, and when there is an error, the ACK / NACK signal generator 58 generates a NACK signal. This result is stored in the memory or the like in association with the process number and NDI (step S28). Note that if no HS-DSCH is received, no ACK / NACK signal is generated and no transmission is performed. However, the value when there is no signal is treated as 0.

  The generated ACK / NACK signal is encoded by the encoding unit 59, modulated by the modulation unit 60, spread by the spreading unit 60a, and then transmitted and transmitted by the transmission radio unit 61. Is transmitted from the antenna 51 to the BS 1 (step S30). At this time, preferably, a fixed offset value is given to the transmission power value of the uplink DPCH, and the HS-DPCCH is transmitted from the UE 5 to the BS 1 with the transmission power value reflecting this offset value.

  The BS 1 that has received the HS-DPCCH signal including the ACK / NACK signal performs predetermined reception radio processing on the signal at the reception radio unit 15, despreads at the despreading unit 16 a, and demodulates at the demodulation unit 16. Demodulated and decoded by the decoding unit 17. From the decoding result, the ACK / NACK extraction unit 18 extracts the ACK / NACK signal and transmits it to the scheduler 20 (step S31).

BS1 transmits a CPICH signal to UE5 in the same manner as in step S21 (step S32), and UE5 measures CQI based on the CPICH signal in the same manner as in steps S22 and S23. (Step S33), the measurement result is transmitted (reported) to BS1 (Step S34).
When the scheduler 1 determines transmission to the UE 5 that has received the ACK / NACK signal based on the reported CQI value in the scheduler 20 (step S35), the BS 1 selects new data if the ACK signal is received. As new transmission, the transmission signal processing described above is performed and new transmission is performed to UE5. If the NACK signal is received, the transmission signal processing described above is performed on the same transmitted data, and the UE 5 is retransmitted (step S38). Prior to the new transmission and retransmission of the data, BS1 transmits a control signal such as a transmission method to UE5 using HS-SCCH, similarly to step S25 (step S36).

The UE 5 that has received the HS-SCCH signal performs the received signal processing described above. At this time, the ACK / NACK misjudgment detection unit 56 compares the process number and NDI at the time of the previous reception stored in the retransmission control unit with the current process number and NDI to determine whether or not there is an ACK / NACK misjudgment. Is confirmed (steps S37, S39, S40).
Preferably, the ACK / NACK error determination detection unit 56 holds an ACK / NACK transmission error table as shown in the following table 3 in a memory (not shown) as table format data or the like, and based on the error table, the ACK / NACK error table The presence or absence of judgment is detected.

That is, when “positive” in Table 3, the UE 5 continues transmission as it is. On the other hand, in the case of “false”, either BS1 has received an ACK reply from UE5 as a NACK or a NACK reply from UE5 has been received as an ACK.
Therefore, in the case of “false” in Table 3, ACK / NACK transmission characteristics are improved by adding new transmission power control. When “positive” in Table 3, for example, as shown in the following equation (11), the power _obtained by adding the offset power value P _{HS-DPCCH_offset} to the uplink DPCH transmission power value P _UL-DPCH The value is the transmission power value of ACK / NACK.

Here, the offset power value P _{HS-DPCCH_offset} can be determined individually for ACK and NACK by the following equations (12) and (13). However, a common value may be used for ACK and NACK.

In BS1 (or RNC which is the _host device thereof), a correction value (transmission power correction information) _{PHS-DPCCH_c} when the erroneous determination occurs is generated and notified in advance from BS1 to _UE5 as a control signal. This control signal can be transmitted using a downlink control channel, preferably downlink A-DPCH, downlink DPCH, or HS-SCCH.
Also, this ACK / NACK transmission power correction value P _{HS-DPCCH_c} is fixed at, for example, 0.5 dB. Note that a negative value of -0.5 dB may be set. That is, the following formulas (14) and (15), the following formulas (16) and (17), the following formulas (18) and (19), or the following formulas (20) And it is good also as (21) Formula. That is, transmission power can be individually controlled by ACK and NACK.

The _{UE 5} (transmission power control unit 57) that has received the ACK / NACK transmission power correction value P _{HS-DPCCH_c} is the first embodiment when the ACK / NACK erroneous determination detection unit 56 determines “false” in Table 3 above. Similarly, the transmission power value at the time of ACK / NACK transmission is corrected (controlled) (step S41). At this time, for example, as shown in the following equation (22), the uplink DPCH transmission power value P _UL-DPCH , the offset transmission power value P _{HS-DPCCH_offset,} and the ACK / NACK correction value P _{HS-DPCCH_c} are added. Thus, the transmission power value P ′ _{ACK / NACK} at the time of ACK / NACK transmission (step S42) is calculated.

  As described above, it is possible to improve the transmission characteristics of ACK / NACK transmitted from the UE 5 to the BS 1 when the ACK / NACK misjudgment occurs in the BS 1, and the occurrence rate of the subsequent ACK / NACK misjudgment in the BS 1 This can be reduced (step S43). Therefore, it is possible to reduce the lack of downlink data and useless downlink transmission from the BS 1 to the UE 5, and to improve the downlink throughput.

Further, it is possible to avoid repeated ACK / NACK misjudgment when there is no change in the radio environment such as a cell edge or high-speed movement.
Furthermore, since it is not necessary to add a pre / post signal to the ACK / NACK as in the enhanced HSDP system, it is possible to reduce the power required for the ACK / NACK transmission and to reduce the power consumption.

In the example shown in FIG. 6, the ACK / NACK misjudgment is performed using the process number, the previous ACK / NACK signal, and the NDI. However, the process number, the previous ACK / NACK signal, and It is also possible to carry out using the result of comparing the contents of the received downlink data and the result of determining whether it is new transmission or retransmission.
As a method of determining retransmission, the previous and current received data are compared, and if they match completely, it may be determined to be retransmission, or a threshold is set, and the received data matches the threshold or more. If it is, it may be determined as retransmission.

In the above-described example, the correction value P _{HS-DPCCH_c} is generated in the BS 1 (or its _host device). However, even when the correction value P _{HS-DPCCH_c} is generated in the transmission power control unit 57 of the _{UE 5,} for example. Good.
[3] Third embodiment (ACK / NACK misjudgment notification)
FIG. 7 is a block diagram showing a configuration of a radio base station (BS) according to the third embodiment of the present invention, and FIG. 8 is a block diagram showing a configuration of a radio terminal (UE) according to the third embodiment of the present invention. Thus, the BS 1 shown in FIG. 7 and the UE 5 shown in FIG. 8 constitute a radio communication system, here an HSDPA system. Also in this example, there may be a plurality of BS1 and UE2 respectively.

(Description of BS)
The BS1 shown in FIG. 7 is the same as or similar to that in the BS1 shown in FIG. 4 in the second embodiment, the transmission buffer 10, the encoding unit 11, the modulation unit 12, the spreading unit 12a, and the transmission radio. Unit 13, antenna 14, reception radio unit 15, despreading unit 16a, demodulation unit 16, decoding unit 17, ACK / NACK extraction unit 18, retransmission control unit 19, scheduler 20, control signal In addition to a generation unit 21, a CQI extraction unit 22, an uplink pilot power calculation unit 24, and a transmission power control unit 25, an ACK / NACK misjudgment signal (ACK / NACK error signal) extraction unit 23 is provided.

  Here, the ACK / NACK misjudgment signal extraction unit 23 extracts an ACK / NACK error signal transmitted from the UE 5 from the decoding result by the decoding unit 17. The extracted ACK / NACK error signal is transmitted to the transmission power control unit 25, and transmission power control (uplink transmission power control) of the ACK / NACK signal from the UE 5 according to the ACK / NACK error signal is performed. This is implemented by the unit 25.

(Description of UE)
On the other hand, the UE 5 shown in FIG. 8 is the same as or similar to that in the BS 1 shown in FIG. 4 in the second embodiment, the antenna 51, the reception radio unit 52, the despreading unit 53a, the demodulation unit 53, A decoding unit 54, a control signal extraction unit 55, an ACK / NACK erroneous determination detection unit 56, a transmission power control unit 57, an ACK / NACK signal generation unit 58, a retransmission control unit 58a, an error detection unit 58b, In addition to an encoding unit 59, a modulation unit 60, a spreading unit 60a, a transmission radio unit 61, a CQI measurement unit 62, and a CQI signal generation unit 63, an ACK / NACK error signal generation unit 64 is provided.

  The ACK / NACK error signal generation unit (notification unit) 64 determines in the ACK / NACK error determination detection unit 56 that an ACK / NACK error determination has occurred in BS 1 as described in the first and second embodiments. In this case, a signal (ACK / NACK error signal) for notifying BS1 of that fact (determination result of ACK / NACK misjudgment) is generated. This signal may be simply a signal notifying the occurrence of erroneous determination, but is preferably a signal indicating the content (state) of the erroneous determination described above. For example, as shown in Table 4 below, it can be defined as a 4-bit signal.

The ACK / NACK error signal is encoded by the encoding unit 59, modulated by the modulation unit 60, spread by the spreading unit 60a, and then subjected to predetermined transmission radio processing by the transmission radio unit 61. And transmitted from the antenna 51 to BS1.
(Description of operation)
The operation (transmission power control) of the HSDPA system configured as described above will be described below with reference to the sequence diagram shown in FIG. However, in FIG. 9, the processes in steps S21 to S41 are the same as or similar to the processes in steps S21 to S41 described in FIG. 6 in the second embodiment.

Then, as described in the first and second embodiments, when UE5 (ACK / NACK misjudgment detection unit 56) determines that an ACK / NACK misjudgment has occurred in BS1, UE5 The NACK error signal generator 64 generates an ACK / NACK error signal and transmits it to BS1 (step S42a).
That is, the ACK / NACK error signal generation unit 64 generates an ACK / NACK error signal (ACK_NACK _error ) according to Table 4, which is encoded by the encoding unit 59, modulated by the modulation unit 60, and spread. After being spread by the unit 60a, the transmission radio unit 61 performs predetermined transmission radio processing and transmits the signal from the antenna 51 to the BS1.

Note that the ACK / NACK error signal (ACK_NACK _error ) may be transmitted to BS1 as an HS-DPCCH (uplink dedicated control channel) signal, or an uplink DPCH (uplink dedicated channel) or UL-SCCH (uplink shared control). Channel), UL-CCCH (uplink common control channel), and UL-SCH (uplink common data channel) signal may be transmitted. Further, in order to identify HS-DSCH data (data transmitted on the downlink data channel) in which ACK / NACK misjudgment has occurred, the process number may be added and transmitted to BS1.

Further, the transmission timing of the ACK / NACK error signal (ACK_NACK _error ) may be before the transmission of the ACK / NACK signal with the corrected transmission power value P ′ _{ACK / NACK} (step S42), as shown in FIG. However, it may be after the transmission of the ACK / NACK signal.
Further, only the OLE_LINK3ACK / NACK error signal (ACK_NACK _error OLE_LINK3) may be transmitted without performing the ACK / NACK transmission.

On the other hand, when the BS 1 receives the ACK / NACK error signal from the UE 5, it is extracted by the ACK / NACK misjudgment signal extraction unit 23 and transmitted to the transmission power control unit 25. The transmission power control unit 25 performs retransmission or new transmission based on the contents of the ACK / NACK error signal (defined in Table 4).
Also, BS1 performs uplink ACK / NACK transmission power control and improves uplink ACK / NACK transmission characteristics in the same manner as in the first and second embodiments. For example, as in the second embodiment, the _{UE 5} is notified of the ACK / NACK transmission power correction value P _{HS-DPCCH — c} (or ACK / NACK transmission power value P _{ACK / NACK} ).

  As described above, in this example, when an ACK / NACK misjudgment is detected in the UE 5 as described in the first and second embodiments, the UE 5 notifies the BS 1 of an ACK / NACK error signal. Therefore, BS1 can recognize that ACK / NACK is erroneously determined. Therefore, it is possible to reduce subsequent loss of downlink data addressed to the UE 5 and useless downlink transmission. Also, uplink ACK / NACK transmission power control can be easily performed.

In addition, you may apply the operation | movement in UE5 mentioned above to BS1. That is, the ACK / NACK transmission power control (correction) may be performed for downlink ACK / NACK transmission for uplink data transmission from UE5 to BS1.
[4] Fourth Embodiment (Offset correction value is notified to UE based on uplink signal of other UE)
FIG. 10 is a block diagram showing a configuration of a radio base station (BS) according to the fourth embodiment of the present invention. The BS 1 shown in FIG. 10 and the UE 5 shown in FIG. 5 or FIG. System). Also in this example, there may be a plurality of BS1 and UE2 respectively.

  The BS 1 shown in FIG. 10 is the same as or similar to the BS 1 shown in FIG. 4 in the second embodiment, respectively, a transmission buffer 10, an encoding unit 11, a modulation unit 12, a spreading unit 12a, and a transmission radio. Unit 13, antenna 14, reception radio unit 15, despreading unit 16a, demodulation unit 16, decoding unit 17, ACK / NACK extraction unit 18, retransmission control unit 19, scheduler 20, control signal In addition to the generation unit 21, the CQI extraction unit 22, the uplink pilot power calculation unit 24, and the transmission power control unit 25, an interference measurement unit 26 is provided.

In addition, when UE5 which comprises the structure (ACK / NACK error signal generation part 64) shown in FIG. 8 as a communicating party of BS1, the ACK / NACK misjudgment signal (ACK / NACK error shown in FIG. 7) is included. A signal) extraction unit 23 is also provided, and the functions and operations thereof are the same as or similar to those already described in the third embodiment.
Here, the interference measurement unit 26 determines that the ACK / NACK signal transmitted from the UE 5 to the BS 1 has an influence on the ACK / NACK signal transmitted from the other UE 5 (interference) based on the result of the despreading by the despreading unit 16a. Is to measure. The measurement result is transmitted to the transmission power control unit 25. The interference can be measured using uplink signals, for example, uplink pilot signals transmitted from the UE 5 at a certain time, uplink ACK / NACK, and uplink DPCH transmission characteristics (CIR, SIR, etc.).

Then, the transmission power control unit 25 of this example uses the ACK / NACK transmission power correction value P _{HS-DPCCH_c} for the _{UE 5} that has received the ACK / NACK signal or all the _{UEs 5} based on the measurement result by the interference measurement unit 26. It has a function of calculating and _{causing the} control signal generation unit 21 to generate a downlink control signal including the correction value P _{HS-DPCCH_c} . This control signal can also be transmitted using a downlink control channel, preferably downlink A-DPCH, downlink DPCH, and HS-SCCH.

(Description of operation)
The operation (ACK / NACK transmission power control) of the HSDPA system configured as described above will be described below with reference to the sequence diagram shown in FIG. However, in FIG. 11, the processes of steps S21 to S43 except for steps S31a, S31b, S31c, S41a, S43a, S43b, and S43c are the steps S21 to S41 described in FIG. 6 in the second embodiment unless otherwise specified. Since the processing is the same as or similar to the above processing, the following description will focus on operations focusing on steps S31a, S31b, S31c, S41a, S43a, S43b, and S43c.

When the BS 1 of this example receives the ACK / NACK signal (or the ACK / NACK error signal (ACK_NACK _error ) described in the third embodiment) transmitted from the UE 5 (steps S31 and S43), the uplink ACK / NACK signal Is measured by the interference measuring unit 27 (steps S31a and S43a).
Then, the transmission power control unit 25 of BS1 calculates the ACK / NACK transmission power correction value P _{HS-DPCCH_c} for the _{UE 5} that has received the ACK / NACK signal or all the _{UEs 5 based} on the result (steps S31b and S43b). .

As a calculation method thereof, for example, it is conceivable to set a threshold SIR _th for the SIR of the uplink ACK / NACK signal and determine the ACK / NACK transmission power correction value P _{HS-DPCCH_c} so as not to exceed the threshold SIR _th .
Further, for example, the initial value of the ACK / NACK transmission power correction value P _{HS-DPCCH_c} is set to 0.5 dB, the control is repeated, and the ACK / NACK transmission power correction value P _{HS-DPCCH_c} is the maximum value within a range not exceeding the threshold SIR _th. Control may be performed so that

Further, when the offset power value P _{HS-DPCCH_offset} is individually set for ACK and NACK, two threshold _values SIR _{th_up} and threshold value SIR _{th_down} are set for the SIR of the uplink ACK / NACK signal, (5) It performs control of delta _ACK and delta _NACK in the formula and (6) may be repeated controlled to approach the respective threshold.
The BS 1 then _causes the control signal generation unit 21 to generate a downlink control signal including the ACK / NACK transmission power correction value P _{HS-DPCCH_c} obtained as described above, and the encoding unit 11, the modulation unit 12, and the spreading unit 12a. Then, it transmits (notifies) the UE 5 or all UEs 5 through the transmission radio unit 13 and the antenna 14 (steps S31c and S43c).

Upon confirming the presence / absence of ACK / NACK misjudgment as described above, the UE 5 performs ACK / NACK transmission power control using the ACK / NACK transmission power correction value P _{HS-DPCCH_c} notified from the BS 1 (step) S41a).
For example, when ACK / NACK misjudgment is detected in UE 5 (ACK / NACK misjudgment detector 56), transmission power controller 57 receives OLE_LINK1 ACK / NACK transmission power correction value P _{HS-DPCCH_c} OLE_LINK1 _{notified from} BS1. _Is reflected in the ACK / NACK transmission power value P _{ACK / NACK} , and the ACK / NACK signal is transmitted from the UE 5 to the BS 1 as the ACK / NACK transmission power value P ′ _{ACK / NACK} (step S43). .

That is, in this example, the BS 1 calculates the ACK / NACK transmission power correction value P _{HS-DPCCH_c} considering the influence of interference caused by the ACK / NACK signal transmitted from the _{UE 5} on the transmission from the other _{UE 5} to the BS 1. _{And UE5} performs ACK / NACK transmission power control using this correction value _{PHS-DPCCH_c} by notifying the said correction value _{PHS-DPCCH_c} from _UE1 to _UE5 .

Therefore, in this example as well, it is possible to improve the transmission characteristics of uplink ACK / NACK, and it is possible to reduce the occurrence rate of subsequent ACK / NACK misjudgment in BS1. As a result, it is possible to reduce downlink data loss and useless downlink transmission addressed to the UE 5, and to improve downlink throughput.
Further, since it is not necessary to add a pre / post signal to the ACK / NACK as in the enhanced HSDPA system, the transmission power can be suppressed and the power consumption can be reduced.

Furthermore, it is possible to reduce uplink interference due to ACK / NACK transmission. As a result, it is possible to improve the transmission characteristics of other uplink communications.
In this example, ACK / NACK transmission power correction value P _{HS-DPCCH_c} is calculated in BS1 and notified to _UE5 . For example, BS1 notifies _UE5 of the measurement result by interference measurement unit 26, and UE5 (For example, the transmission power control unit 57) may calculate the ACK / NACK transmission power correction value P _{HS-DPCCH_c} based on the notified measurement result. [5] Fifth Embodiment (CQI in BS Control used)
FIG. 12 is a block diagram showing the configuration of a radio base station (BS) according to the fifth embodiment of the present invention. The BS 1 shown in FIG. 12 and the UE 5 shown in FIG. 5 or FIG. System). In this example, there may be a plurality of BS1 and UE5.

  The BS 1 shown in FIG. 12 is the same as or similar to the BS 1 shown in FIG. 4 in the second embodiment, the transmission buffer 10, the encoding unit 11, the modulation unit 12, the spreading unit 12a, and the transmission radio. Unit 13, antenna 14, reception radio unit 15, despreading unit 16a, demodulation unit 16, decoding unit 17, ACK / NACK extraction unit 18, retransmission control unit 19, scheduler 20, control signal In addition to the generation unit 21, the CQI extraction unit 22, the uplink pilot power calculation unit 24, and the transmission power control unit 25, a CQI storage unit 27 is provided.

Also in this example, when UE 5 having the configuration shown in FIG. 8 (ACK / NACK error signal generation unit 64) is included as a communication partner of BS1, the ACK / NACK misjudgment signal shown in FIG. An (ACK / NACK error signal) extraction unit 23 is also provided, and the functions and operations thereof are the same as or similar to those already described in the third embodiment.
Here, the CQI storage unit 27 receives the CQI extracted by the CQI extraction unit 22, that is, the transmission target of the scheduler 20 during downlink transmission (for example, HS-DSCH transmission) to the UE 5 (new and retransmission). The CQI used as a selection criterion for the UE 5 is stored. The stored contents are referred to (read out) as appropriate by the transmission power control unit 25.

Then, the transmission power control unit 25 of this example calculates a change in the propagation environment based on the CQI difference CQI _diff used for each of a plurality of downlink transmissions stored in the CQI storage unit 27, and the difference CQI _diff A function of obtaining an ACK / NACK transmission power correction value corresponding to the UE and transmitting it to the UE 5 as a downlink control signal is provided. The control signal is generated by the control signal generation unit 21 and can be transmitted using a downlink control channel, preferably a downlink A-DPCH, a downlink DPCH, or an HS-SCCH.

(Description of operation)
Hereinafter, the operation (ACK / NACK transmission power control) of the HSDPA system configured as described above will be described with reference to the sequence diagram shown in FIG. 13 and the flowchart shown in FIG. However, in FIG. 13, the processes of steps S21 to S43 except for steps S23a, S34a, S34b, and S34c are the same as or similar to the processes of steps S21 to S41 described in FIG. 6 in the second embodiment unless otherwise specified. It is. Further, the processing in step S41a is the same as or similar to the processing described with reference to FIG. Below, it demonstrates centering around the operation | movement paying attention to step S23a, S34a, S34b, S34c.

That is, as described above, the UE 5 measures the CQI based on the downlink pilot signal received from the BS 1 and transmits it to the BS 1 (steps S22, S23, S33, and S34 in FIG. 13). Are extracted by the CQI extraction unit 22 and sequentially stored in the CQI storage unit 27 (steps S23a and S34a). In FIG. 13, CQI transmitted by UE 5 for the first time is CQI ₁ , and CQI transmitted for the second time is CQI ₂ .

In BS1, the transmission power control unit 25 obtains a difference CQI _diff between these CQI ₁ and CQI _2, and an ACK / NACK transmission power correction value P _{HS-DPCCH_c2} (= δ) corresponding to the difference CQI _diff. Is obtained (step S34b), and is transmitted to the UE 5 by a downlink control signal (step S34c).
In FIG. 13, the transmission of the control signal is performed before scheduling (step S35), but it may be performed after scheduling. Preferably, the control signal may be transmitted before uplink ACK / NACK transmission (step S42) for downlink data transmission (HS-DSCH).

Here, the said ACK / NACK transmission power correction method in BS1 is demonstrated using the flowchart shown in FIG. Here, it is assumed that the ACK / NACK transmission power correction value P _{HS-DPCCH_c2} is calculated in the BS 1 and notified to the _{UE 5} regardless of the presence / absence of the ACK / NACK misjudgment.
In BS1, in transmission power control unit 25, threshold CQI _{diff_th} related to CQI difference CQI _diff is preset in a memory (not shown) or the like (step S51).

Thereafter, the transmission power control unit 25 reads the downlink CQI ₁ used for the previous HS-DSCH transmission and the downlink CQI ₂ used for the next HS-DSCH transmission from the CQI storage unit 27 (steps S52 and S53). The difference CQI _diff is obtained by the following equation (23) (step S54). It can be determined that the greater the difference CQI _diff is, the greater the variation in the propagation environment is.

Therefore, the transmission power control unit 25, by comparing the threshold CQI _{Diff_th} said differential CQI _diff, differential CQI _diff exceeds the threshold _{CQI diff_th (CQI diff> CQI diff_th} ) whether to verify (step S55), if it exceeds, the fluctuation (degradation) of the propagation environment is large, so it is determined that an ACK / NACK misjudgment occurs in the HS-DPCCH transmission power value based on the normal uplink DPCH power control, and the difference The ACK / NACK transmission power correction value P _{HS-DPCCH_c2} corresponding to CQI _diff is _set to δ (from the YES route in step S55 to step S56).

On the other hand, when the difference CQI _diff is _{equal to} or less than the threshold CQI _{diff_th} (CQI _diff ≦ CQI _{diff_th} ), the transmission power control unit 25 has a small fluctuation (degradation) of the propagation environment, and therefore, HS based on normal uplink DPCH power control -It is determined that ACK / NACK misjudgment does not occur even with the DPCCH transmission power value, and the ACK / NACK transmission power correction value P _{HS-DPCCH_c2} corresponding to the difference CQI _diff is preferably set to 0 (from the NO route in step S55) Step S57).

Then, the transmission power control unit 25 notifies the _{UE 5} of the obtained ACK / NACK transmission power correction value P _{HS-DPCCH_c2} with a control signal (step S58). Incidentally, ACK / NACK transmission power value P "To notify the _{ACK / NACK,} due to (24) or following (25 formula), ACK / NACK transmission power value P" Request _{ACK / NACK} (Step S58).

That is, the obtained ACK / NACK transmission power correction value P _{HS-DPCCH_c2} may be set as a part of the ACK / NACK correction value P _{HS-DPCCH_c} or may be set as another.
Then, as illustrated in FIG. 13, the BS 1 selects (schedules) the target UE 5 to perform downlink transmission based on the CQI from each aggregated UE 5 in the scheduler 20 (step S35), and transmits to the transmission target UE 5. Is started (steps S36 and S38).

When the UE 5 detects an ACK / NACK misjudgment similarly to the above-described embodiment (steps S37, S39, and S40), the ACK / NACK transmission power correction value P _{HS-DPCCH_c2} (or alternatively) notified from the BS 1 as described above (or Based on the transmission power value P ″ _{ACK / NACK} ), the transmission power value of ACK / NACK is corrected and ACK / NACK transmission to BS1 is performed (steps S41 and S42).

  That is, in this example, when an uplink ACK / NACK transmission error occurs, BS1 determines a change in the propagation environment based on the radio channel characteristic information (CQI) notified from UE5, and according to the change, A transmission power correction value for transmitting uplink ACK / NACK is calculated and notified to the UE 5, and the UE 5 that has received this notification controls the transmission power of uplink ACK / NACK transmission based on the correction value.

Therefore, the same effects and advantages as in the fourth embodiment can be obtained, and the ACK / NACK misjudgment rate can be further reduced to improve the ACK / NACK transmission characteristics.
[6] Sixth Embodiment (Control using CQI in UE)
FIG. 15 is a block diagram showing a configuration of a radio terminal (UE) according to the sixth embodiment of the present invention. The radio communication system includes the UE 5 shown in FIG. 15 and the BS 1 shown in FIG. 4, FIG. 7, or FIG. (HSDPA system) is configured. In this example, there may be a plurality of BS1 and UE5.

  The UE 5 shown in FIG. 15 is the same as or similar to that in the UE 5 shown in FIG. 5 in the second embodiment, respectively, an antenna 51, a reception radio unit 52, a despreading unit 53a, a demodulation unit 53, and a decoding unit. 54, a control signal extraction unit 55, an ACK / NACK error determination detection unit 56, a transmission power control unit 57, an ACK / NACK signal generation unit 58, a retransmission control unit 58a, an error detection unit 58b, an encoding In addition to the unit 59, the modulation unit 60, the spreading unit 60a, the transmission radio unit 61, the CQI measurement unit 62, and the CQI signal generation unit 63, the CQI storage unit 65 is provided.

Here, the CQI storage unit 65 stores the CQI measured by the CQI measurement unit 62. The stored contents are referred to (read out) as appropriate by the transmission power control unit 57.
The transmission power control unit 57 of this example stores a plurality of CQIs stored in the CQI storage unit 65, preferably at timings before and after detection of an ACK / NACK erroneous determination by the ACK / NACK erroneous determination detection unit 56. ACK / NACK transmission power control is performed based on the CQI. For example, based on CQI ₁ measured immediately before ACK / NACK transmission and CQI ₂ immediately before ACK / NACK transmission immediately after ACK / NACK erroneous determination is detected by ACK / NACK erroneous determination detection unit 56, ACK / NACK NACK transmission power control can be performed.

That is, in the fifth embodiment, BS1 performs uplink ACK / NACK transmission power control on the basis of CQI notified from UE5 in BS1, whereas in this example, UE5 is uplinked on the basis of CQI measured in UE5. ACK / NACK transmission power control is performed.
(Description of operation)
The operation (ACK / NACK transmission power control) of the HSDPA system configured as described above will be described below with reference to the sequence diagram shown in FIG. 16 and the flowchart shown in FIG. However, in FIG. 16, the processes of steps S21 to S43 excluding steps S23b and S34d are the same as or similar to the processes of steps S21 to S41 described with reference to FIG. 6 in the second embodiment unless otherwise specified. Further, the processing in step S41a is the same as or similar to the processing described with reference to FIG. Below, it demonstrates centering around the operation | movement paying attention to step S23b, S34d.

That is, as described above, the UE 5 measures the CQI based on the downlink pilot signal received from the BS 1 and transmits it to the BS 1 (steps S22, S23, S33, S34 in FIG. 16), but stores the CQI in the CQI storage. Each is stored in the unit 65 (steps S23b, S34d). Also in this example (FIG. 16), the CQI transmitted by the UE 5 for the first time is CQI ₁ , and the CQI transmitted for the second time is CQI ₂ .

The BS 1 then selects (schedules) the target UE 5 to perform downlink transmission based on the CQI from each UE 5 aggregated in the scheduler 20 (step S35), and starts downlink transmission to the transmission target UE 5 ( When the _{UE 5} detects an ACK / NACK misjudgment similarly to the above-described embodiment (steps S37, S38), the UE 5 detects the ACK / NACK transmission power correction value P _{HS-DPCCH_c3} (or transmission power). Value) is calculated, and ACK / NACK transmission to BS1 is performed with the corrected transmission power value of ACK / NACK (steps S41 and S42).

Here, the said ACK / NACK transmission power correction method in UE5 is demonstrated using the flowchart shown in FIG.
In the UE 5, in the transmission power control unit 57 (or the retransmission control unit 58a), a threshold CQI _{diff_th} related to the CQI difference CQI _diff is preset in a memory or the like (not shown) (step S61).

Thereafter, the transmission power control unit 57 (or the retransmission control unit 58a) receives the CQI ₁ measured immediately before the ACK / NACK transmission from the CQI storage unit 65 and the ACK / NACK misjudgment detection unit 56. The CQI ₂ immediately before the ACK / NACK transmission immediately after the detection is read (steps S62 and S63), and the difference CQI _{diff between them} is obtained (step S64). Also in this example, it can be determined that the greater the difference CQI _diff is, the greater the variation in the propagation environment is.

Therefore, the transmission power control unit 57 (or the retransmission control unit 58a) compares the difference CQI _diff with the threshold CQI _{diff_th,} and _whether the difference CQI _diff exceeds the threshold CQI _{diff_th} (CQI _diff > CQI _{diff_th} ). (Step S65), if it exceeds, the fluctuation (degradation) of the propagation environment is large. Therefore, in the HS-DPCCH transmission power value based on the normal uplink DPCH power control, an ACK / NACK misjudgment is detected. The ACK / NACK transmission power correction value P _{HS-DPCCH_c3} corresponding to the difference CQI _diff is calculated as δ (from the YES route in step S65 to step S66).

On the other hand, when the difference CQI _diff is _{equal to} or less than the threshold CQI _{diff_th} (CQI _diff ≦ CQI _{diff_th} ), the transmission power control unit 57 has a small fluctuation (degradation) in the propagation environment, and therefore HS based on normal uplink DPCH power control is used. -It is determined that ACK / NACK misjudgment does not occur even with the DPCCH transmission power value, and the ACK / NACK transmission power correction value P _{HS-DPCCH_c3} corresponding to the difference CQI _diff is _set to 0 (from the NO route of step S65 to step S67). ).

Then, based on the obtained ACK / NACK transmission power correction value P _{HS-DPCCH_c3} , the transmission power control unit 57 performs ACK / NACK transmission power value P ″ _{ACK / according to the following} equation (26) and equation (27). _NACK is obtained (step S68).

That is, the obtained ACK / NACK transmission power correction value P _{HS-DPCCH_c3} may be set as a part of the ACK / NACK correction value P _{HS-DPCCH_c} or may be set as another.
As described above, in this example, radio channel characteristic information (CQI) when UE 5 on the receiving side performs ACK / NACK transmission is stored, and an ACK / NACK transmission error in BS 1 on the transmitting side is detected. In this case, the stored previous CQI is compared with the current CQI, and a transmission power correction value for transmitting ACK / NACK to BS 1 is calculated based on the comparison result, and this is used to transmit ACK / NACK transmission. To do.

  That is, when an ACK / NACK transmission error occurs, the transmission power for transmitting ACK / NACK is controlled based on CQI (radio channel characteristics) measured by UE 5 on the receiving side. Therefore, the same effects or advantages as those of the fourth embodiment can be obtained. In this case, the CQI measured and calculated immediately before the ACK / NACK transmission is used in the UE 5, that is, the ACK / Since CQI that is closer in time to NACK transmission is used, the ACK / NACK transmission power control system can be improved as compared with the fifth embodiment.

[7] Seventh Embodiment (Correction using ACK / NACK transmission power value difference in UE)
FIG. 18 is a block diagram showing a configuration of a radio terminal (UE) according to the seventh embodiment of the present invention. The radio communication system includes the UE 5 shown in FIG. 18 and the BS 1 shown in FIG. 4, FIG. 7 or FIG. (HSDPA system) is configured. In this example, there may be a plurality of BS1 and UE5.

  The UE 5 shown in FIG. 18 is the same as or similar to that in the UE 5 shown in FIG. 5 in the second embodiment, the antenna 51, the reception radio unit 52, the despreading unit 53a, the demodulation unit 53, and the decoding unit. 54, a control signal extraction unit 55, an ACK / NACK error determination detection unit 56, a transmission power control unit 57, an ACK / NACK signal generation unit 58, a retransmission control unit 58a, an error detection unit 58b, an encoding In addition to a unit 59, a modulation unit 60, a spreading unit 60a, a transmission radio unit 61, a CQI measurement unit 62, and a CQI signal generation unit 63, an ACK / NACK transmission power storage unit 66 is provided.

Here, the ACK / NACK transmission power storage unit 66 stores the ACK / NACK transmission power value at that time for each ACK / NACK transmission to the BS 1. The stored content is appropriately referred to (read out) by the transmission power control unit 57.
The transmission power control unit 57 of this example has a function of performing transmission power control by correcting the ACK / NACK transmission power value based on the difference between the ACK / NACK transmission power values when transmitting ACK / NACK. . That is, in the fifth and sixth embodiments, the change in the propagation environment is determined based on the difference in CQI. In this example, the propagation environment is determined based on the difference in ACK / NACK transmission power value. Determine fluctuations. Note that this function may be included in the retransmission control unit 58a.

(Description of operation)
Hereinafter, the operation (ACK / NACK transmission power control) of the HSDPA system configured as described above will be described with reference to the sequence diagram shown in FIG. 19 and the flowchart shown in FIG. However, in FIG. 19, the processes in steps S21 to S43 excluding step S29a are the same as or similar to the processes in steps S21 to S41 described in FIG. 6 in the second embodiment unless otherwise specified. Further, the processing in step S41a is the same as or similar to the processing described with reference to FIG.

That is, as shown in FIG. 19, the UE 5 (transmission power control unit 57) that has received the HS-DSCH signal (step S26) and transmitted ACK / NACK (step S30) receives the ACK / NACK transmission power value P _{ACK. / NACK} is stored in the ACK / NACK transmission power storage unit 66 (step S29a).
Thereafter, the UE 5 (the transmission power control unit 57 or the retransmission control unit 58a) performs the ACK / NACK transmission (step S42) for the reception of the next HS-DSCH signal (step S38), as shown in FIG. The / NACK transmission power value P _{ACK / NACK} is read from the ACK / NACK transmission power storage unit 66 and set as P _{ACK / NACK_before} (step S71).

Here, when an ACK / NACK misjudgment detection unit 56 detects an ACK / NACK misjudgment detection unit 56, the transmission power control unit 57 (or retransmission control unit 58a) performs processing on data for which an ACK / NACK misjudgment has been found. The ACK / NACK transmission power value calculated (not corrected) by the normal calculation method is set as P _{ACK / NACK_after} (step S72). The normal calculation method is, for example, adding an offset transmission power value to an uplink DPCH transmission power value.

Then, as shown in the following equation (28), the transmission power control unit 57 receives the ACK / NACK transmission power value P _{ACK / NACK_after} and the ACK / NACK transmission power value P _ACK that caused the ACK / NACK misjudgment. _/ calculates the difference P _{ACK / NACK_diff} the _{NACK_before} (step S73).

Transmission power control unit 57 further includes a the difference P _{ACK / NACK_diff} obtained, the difference P _{ACK / NACK_diff} compares the threshold P _{ACK / NACK_diff_th} about calculated difference P _{ACK / NACK_diff} threshold P _{ACK /} It is confirmed whether or not _{NACK_diff_th} is exceeded (P _{ACK / NACK_diff} > P _{ACK / NACK_diff_th} ) (step S74). Note that the threshold P _{ACK / NACK_diff_th} is set and stored in advance in a memory (not shown) of the transmission power control unit 57, for example.

As a result, if it exceeds, the transmission power control unit 57 determines that the fluctuation (degradation) of the propagation environment is large, and an ACK / NACK error is detected with the HS-DPCCH transmission power value based on normal uplink DPCH power control. It is determined that the determination occurs, and ACK / NACK transmission power correction value P _{HS-DPCCH_c4} corresponding to the calculated difference P _{ACK / NACK_diff} is calculated as δ (from YES route of step S74 to step S75).

On the other hand, if the calculated difference P _{ACK / NACK_diff} is less than or equal to the threshold P _{ACK / NACK_diff_th} (P _{ACK / NACK_diff} ≦ P _{ACK / NACK_diff_th} ), the transmission power control unit 57 sets the ACK / NACK transmission power correction value P _{HS-DPCCH_c4} . 0 (step S76 from the NO route of step S74).
The transmission power control unit 57 uses the ACK / NACK transmission power correction value P _{HS-DPCCH_c4} thus obtained, as shown in the following equation (29), the ACK / NACK transmission power value P ′ ″ _{ACK. / NACK} is calculated (step S77). The ACK / NACK transmission power value P ′ ″ _{ACK / NACK} is stored in the ACK / NACK transmission power storage unit 66.

As shown in the following equation (30), the ACK / NACK transmission power correction value P _{HS-DPCCH_c4} may be set as a part of the ACK / NACK correction value P _{HS-DPCCH_c} as in the _fifth embodiment. .

  Alternatively, it may be set by the following equation (31).

  Furthermore, the present embodiment may be applied to the fifth embodiment and set by the following equation (32).

As described above, also in this embodiment, by performing ACK / NACK transmission power control (correction), ACK / NACK transmission characteristics are improved, and the same effects or advantages as in the fourth embodiment are obtained.
Note that the ACK / NACK transmission power control (correction) in this example can also be performed on the BS1 side by transmitting (notifying) the ACK / NACK transmission power value from the UE 5 to the BS1.

In the above-described example, ACK / NACK transmission power correction is performed when an ACK / NACK erroneous determination is detected. However, regardless of the presence or absence of an ACK / NACK erroneous determination, the ACK / NACK transmission power correction is performed. May be implemented.
[8] Eighth Embodiment (Reduction of received signal processing in UE)
FIG. 21 is a block diagram showing a configuration of a radio terminal (UE) according to the eighth embodiment of the present invention. The UE 5 shown in FIG. 21 and the BS 1 shown in FIG. 4, FIG. 7, FIG. 10, or FIG. A wireless communication system (HSDPA system) is configured. In this example, there may be a plurality of BS1 and UE5.

  The UE 5 shown in FIG. 21 is the same as or similar to that in the UE 5 shown in FIG. 5 in the second embodiment, respectively, an antenna 51, a reception radio unit 52, a despreading unit 53a, a demodulation unit 53, and a decoding unit. 54, a control signal extraction unit 55, an ACK / NACK error determination detection unit 56, a transmission power control unit 57, an ACK / NACK signal generation unit 58, a retransmission control unit 58a, an error detection unit 58b, an encoding In addition to a unit 59, a modulation unit 60, a spreading unit 60 a, a transmission radio unit 61, a CQI measurement unit 62, and a CQI signal generation unit 63, a reception control unit 67 is provided.

  Here, the reception control unit 67 controls reception processing of the downlink signal from the BS1. For example, when it is determined from the detection result of the ACK / NACK misjudgment detection unit 56 that retransmission is performed from BS1 despite transmission of ACK to BS1, downlink data (HS-DSCH) is received. Or reception control is performed so that downlink data is not despread, demodulated or decoded. In addition, the said reception control part 67 can also be applied to UE5 in each above-mentioned embodiment.

(Description of operation)
Hereinafter, the operation (reception process reduction) of the UE 5 configured as described above will be described with reference to the flowchart shown in FIG.
That is, as described in the first to seventh embodiments, the UE 5 receives the HS-SCCH prior to the next downlink data reception after the ACK / NACK transmission (FIGS. 6, 9, 11, and 13). , FIG. 16 or FIG. 19), the result of confirming the process number (Pn) and NDI by the ACK / NACK misjudgment detection unit 56 (steps S81 and S82), although ACK is transmitted to BS1 If it is determined that retransmission is performed from the BS1, it is determined that the ACK is mistakenly interpreted as NACK in the BS1 (YES route in step S83).

  Then, the UE 5 receives, for example, only the HS-SCCH signal and does not receive the HS-DSCH signal, that is, receives the downlink control signal for downlink data transmission, but receives the downlink data by the reception control unit 76. The downlink reception process is controlled so that it does not occur. Alternatively, downlink data (HS-DSCH signal) is received, but despreading, demodulation, or decoding is not performed. For example, the despreading unit 53a, the demodulating unit 53, and the decoding unit 54 are controlled, and these operations are stopped or the power supply is stopped (step S84). Since the downlink data has already been received without error, ACK is transmitted again.

On the other hand, when BS1 correctly receives ACK from UE5 and new data is transmitted to UE5, that is, when an ACK / NACK misjudgment is not detected (NO route in step S84), UE5 (reception control unit) 67) performs normal reception processing (step S85).
Thereafter, the UE 5 performs the ACK / NACK transmission power correction described in the first to seventh embodiments by the transmission power control unit 57 (or the retransmission control unit 58a), and transmits ACK / NACK to the BS1.

As described above, according to this example, when UE 5 transmits ACK to BS 1 and wasteful retransmission is performed from BS 1, wasteful received signal processing can be reduced. It becomes possible to reduce the power consumption.
Note that the received signal processing reduction operation can also be applied to the processing in BS1, that is, the uplink data reception processing.

[9] Ninth Embodiment (Control Using CQI and ACK / NACK Transmission Power Control Value)
FIG. 23 is a block diagram showing a configuration of a radio terminal (UE) according to the ninth embodiment of the present invention. The radio communication system includes the UE 5 shown in FIG. 23 and the BS 1 shown in FIG. 4, FIG. 7, or FIG. (HSDPA system) is configured. In this example, there may be a plurality of BS1 and UE5.

  The UE 5 shown in FIG. 23 is the same as or similar to that in the UE 5 shown in FIG. 5 in the second embodiment, respectively, an antenna 51, a reception radio unit 52, a despreading unit 53a, a demodulation unit 53, and a decoding unit. Unit 54, control signal extraction unit 55, ACK / NACK error determination detection unit 56, transmission power control unit 57, ACK / NACK signal generation unit 58, retransmission control unit 58a, error detection unit 58b, code In addition to a conversion unit 59, a modulation unit 60, a spreading unit 60a, a transmission radio unit 61, a CQI measurement unit 62, and a CQI signal generation unit 63, the CQI storage described in the sixth embodiment (FIG. 15) Unit 65 and the ACK / NACK transmission power storage unit 66 described in the seventh embodiment (FIG. 18).

That is, the UE 5 in this example determines a change in the propagation environment based on both the CQI stored in the UE 5 and the ACK / NACK transmission power value, and controls the ACK / NACK transmission power.
(Description of operation)
The operation (ACK / NACK transmission power control) will be described below with reference to the sequence diagram shown in FIG. 24 and the flowchart shown in FIG. However, in FIG. 24, the processes of steps S21 to S43 excluding steps S23b, S29a, and S34b are the same as or similar to the processes of steps S21 to S41 described in FIG. 6 in the second embodiment unless otherwise specified. . Further, the processing in step S41a is the same as or similar to the processing described with reference to FIG. Further, the processing in steps S23b and S34d is the same as or similar to the processing described in steps S23b and S34d in FIG. 16 in the sixth embodiment, and the processing in step S29a is the same as that in FIG. 19 in the seventh embodiment. This process is the same as or similar to the process described in step S29a.

That is, as shown in FIG. 24, UE5 measures CQI based on the downlink pilot signal received from BS1 and transmits it to BS1 as described above (steps S22, S23, S33, S34). The CQI is stored in the CQI storage unit 65 (steps S23b and S34d). Also in this example (FIG. 24), CQI transmitted by UE 5 for the first time is CQI ₁ , and CQI transmitted for the second time is CQI ₂ .

After that, UE5 receives the HS-DSCH signal from BS1 (step S26) and transmits ACK / NACK for this (step S30), but UE5 (transmission power control unit 57 or retransmission control unit 58a) / NACK transmission power value P _{ACK / NACK} is stored in the ACK / NACK transmission power storage unit 66 (step S29a).
The BS 1 selects (schedules) the target UE 5 to perform downlink transmission based on the aggregated CQI from each UE 5 in the scheduler 20 (step S35), and starts downlink transmission to the transmission target UE 5 (step S36). , S38), the UE 5 detects an ACK / NACK misjudgment in the same manner as the above-described embodiment (steps S37, S39, S40), and _changes the CQI difference CQI _diff and the ACK / NACK transmission power value difference P _{ACK / NACK_diff} . Based on this, an ACK / NACK transmission power correction value P _{HS-DPCCH_c4} (or transmission power value) is calculated, and ACK / NACK transmission to BS 1 is performed with the corrected transmission power value of ACK / NACK (step S41). , S42).

Here, the said ACK / NACK transmission power correction method in UE5 is demonstrated using the flowchart shown in FIG. Note that the UE 5, and the threshold CQI _{Diff_th} about CQI differential CQI _diff, and the threshold value P _{ACK / NACK_diff_th} about ACK / NACK transmission power value difference P _{ACK / NACK_diff,} for example, transmission power control section 57 (or the retransmission control unit 58a) Are previously set and stored in a memory (not shown).

As shown in FIG. 25, the transmission power control unit 57 (or retransmission control unit 58a) of the UE 5 stores the CQI memory prior to ACK / NACK transmission (steps S38 and S42 in FIG. 24) for reception of the HS-DSCH signal. Read CQI ₁ measured immediately before ACK / NACK transmission and CQI ₂ immediately before ACK / NACK transmission immediately after ACK / NACK erroneous determination is detected by ACK / NACK erroneous determination detection unit 56 from step 65 (step S91, S92).

Also, the transmission power control unit 57 reads the previous ACK / NACK transmission power value P _{ACK / NACK} from the ACK / NACK transmission power storage unit 66 and _sets it as P _{ACK / NACK_before} (step S93). The order of reading out these CQI ₁ , CQI ₂ and ACK / NACK transmission power values P _{ACK / NACK} is not limited.
Here, when an ACK / NACK misjudgment detection unit 56 detects an ACK / NACK misjudgment detection unit 56, the transmission power control unit 57 uses the normal calculation method based on CQI ₁ to transmit the ACK / NACK transmission power value P _{ACK / NACK_before} is calculated, and ACK / NACK transmission power value P _{ACK / NACK_after} is calculated by a normal calculation method based on CQI ₂ (step S94).

Then, transmission power control section 57, following the difference P _{ACK / NACK_diff} with these ACK / NACK transmission power value P _{ACK / NACK_after} and ACK / NACK erroneous determination ACK / NACK transmission caused the power value P _{ACK / NACK_before} (33) is calculated (step S95).

Subsequently, the transmission power control unit 57 compares CQI ₁ and CQI ₂ (step S96). If CQI ₁ is equal to or higher than CQI ₂ (YES in step S96), the transmission power control unit 57 calculates based on CQI ₂ . The ACK / NACK transmission power value P _{ACK / NACK_after} is _set as a temporary ACK / NACK transmission power value P _{ACK / NACK_temp} (step S97). Otherwise (NO in step S96), the calculation is based on CQI ₁ The ACK / NACK transmission power value P _{ACK / NACK_before} is _set as a temporary ACK / NACK transmission power value P _{ACK / NACK_temp} (step S98).

Then, the transmission power control unit 57 checks whether or not the difference P _{ACK / NACK_diff} exceeds the threshold value P _{ACK / NACK_diff_th} (step S99), and if it exceeds, the fluctuation (deterioration) of the propagation environment is large. ACK / NACK transmission power correction corresponding to the calculated difference P _{ACK / NACK_diff} by determining that an ACK / NACK misjudgment occurs in the HS-DPCCH transmission power value based on normal uplink DPCH power control The value P _{HS-DPCCH_c5} is calculated as δ (from the YES route in step S99 to step S100).

On the other hand, if the calculated difference P _{ACK / NACK_diff} is _{equal to} or _smaller than the threshold value P _{ACK / NACK_diff_th} (P _{ACK / NACK_diff} ≦ P _{ACK / NACK_diff_th} ), the transmission power control unit 57 sets the ACK / NACK transmission power correction value P _{HS-DPCCH_c5} . 0 (step S101 from the NO route of step S99).
Then, the transmission power control unit 57 sets the ACK / NACK transmission power correction value P _{HS-DPCCH_c5} to the temporary ACK / NACK transmission power value P _{ACK / NACK_temp} as shown in the following equation (34). In addition, the corrected ACK / NACK transmission power value P ″ ″ _{ACK / NACK} is calculated (step S102, step S41 in FIG. 24).

The ACK / NACK transmission power value P ″ ″ _{ACK / NACK} is stored in the ACK / NACK transmission power storage unit 66 in preparation for the next transmission power correction.
Then, UE5 performs ACK / NACK transmission to BS1 with this ACK / NACK transmission power value P ″ ″ _{ACK / NACK} (step S42 in FIG. 24).
That is, the UE 5 in this example compares the stored previous radio channel characteristic information (CQI ₁ ) with the current radio channel characteristic information (CQI ₂ ), and if the radio channel characteristic is improved, Based on the radio channel characteristic information (CQI ₂ ), if it is degraded, the ACK / NACK transmission power value is calculated based on the stored previous radio channel characteristic information (CQI ₁ ), and the power value The ACK / NACK transmission is performed at.

Therefore, the ACK / NACK transmission characteristics can be improved, and the same effects or advantages as in the fourth embodiment can be obtained.
The above-described operation can also be applied to the processing in BS1, that is, the downlink ACK / NACK transmission for the uplink data.
[10] Tenth Embodiment (Continuation of ACK / NACK transmission power correction after detection of erroneous determination)
In the first to ninth embodiments described above, ACK / NACK transmission power control (correction) is performed based on the fact that the process number is the same and that an ACK / NACK misjudgment has occurred. Therefore, it is assumed that the same ACK / NACK transmission power correction is performed for downlink data having the same process number.

  For example, as shown in FIG. 26, when focusing on downlink data with process number = 1, UE 5 performs transmission power correction based on first transmission power correction # 1 when performing second ACK / NACK transmission power correction. Perform # 1 '. Note that any of the correction methods described in the above-described embodiments may be applied to the transmission power correction here. However, the first transmission power correction # 1 can be used as it is.

Also, even if the process number is the same, if no ACK / NACK misjudgment occurs, it is assumed that ACK / NACK transmission power correction is not performed (for example, for the downlink data of process number = 3, 4 in FIG. 26). ACK / NACK transmission).
On the other hand, in the present embodiment, ACK / NACK transmission power correction is performed on downlink data with different process numbers and downlink data when the ACK / NACK misjudgment does not occur with the same process number.

  For example, FIG. 27 shows a case where ACK / NACK misjudgment occurs for downlink data of the same process number (= 1) and ACK / NACK transmission power correction is performed. Thereafter, UE5 (transmission power control unit 57) performs transmission using the first transmission power correction # 1 regardless of the presence or absence of ACK / NACK misjudgment in ACK / NACK transmission for downlink data of the same process number. .

For example, as shown in FIG. 28, UE 5 (transmission power control unit 57 or retransmission control unit 58a) performs the first ACK / NACK transmission for a certain process number M ₁ (M ₁ = 1 in FIG. 28). when carrying out the power correction # 1, until the transmission of the same process number _{M 1} occurs, holds the ACK / NACK transmission power correction value, if the ACK / NACK erroneous determination occurs, the ACK / NACK transmission power correction value ACK / NACK transmission power correction # 1 ′ is used to perform the same processing thereafter.

Furthermore, the UE 5 (the transmission power control unit 57 or the retransmission control unit 58a), for example, as shown in FIG. 29, performs the _first ACK / NACK for the downlink data of a certain process number M ₁ (M ₁ = 1 in FIG. 29). After performing transmission power correction # 1, ACK / NACK misjudgment also occurs for downlink data of a different process number M ₂ (M ₂ = 4 in FIG. 29), and ACK / NACK transmission power correction is performed. and if, first the ACK / NACK transmission power correction # 2 performed on the downlink data of the process number _{M 2} based on OLE_LINK4ACK / NACK transmission power correction OLE_LINK4 # 1, hereinafter, it is also possible to repeat the same processing.

That is, when the UE 5 detects an ACK / NACK misjudgment and corrects the ACK / NACK transmission power, the UE 5 can correct the transmission power for ACK / NACK transmission for other subsequent downlink data. Also, it is possible to correct the transmission power only for ACK / NACK transmission for downlink data in which ACK / NACK misjudgment is detected.
As described above, the ACK / NACK transmission power correction described in the first to ninth embodiments is applied to downlink data of different process numbers and downlink data when no ACK / NACK misjudgment occurs in the same process number. By applying, more ACK / NACK transmission characteristics can be improved. Therefore, it is possible to further reduce the occurrence rate of ACK / NACK misjudgment and further improve the throughput.

The operation of this example can also be applied to the processing in BS1, that is, the downlink ACK / NACK transmission for the uplink data.
[11] Eleventh Embodiment (Correspondence when NACK is mistaken as ACK (retransmission request for missing data))
FIG. 30 is a block diagram showing the configuration of a radio base station (BS) according to the eleventh embodiment of the present invention. The radio communication system (HSDPA system) includes BS 1 shown in FIG. 30 and UE 5 shown in FIG. 8, for example. Is configured. In this example, there may be a plurality of BS1 and UE5.

  30 is the same as or similar to that in BS 1 shown in FIG. 4 in the second embodiment, for example, a transmission buffer 10, an encoding unit 11, a modulation unit 12, a spreading unit 12a, A transmission radio unit 13, an antenna 14, a reception radio unit 15, a despreading unit 16a, a demodulation unit 16, a decoding unit 17, an ACK / NACK extraction unit 18, a retransmission control unit 19, a scheduler 20, Control signal generation unit 21, CQI extraction unit 22, uplink pilot power calculation unit 24, transmission power control unit 25, and ACK / NACK misjudgment signal that is the same as or similar to that described above with reference to FIG. 7 in the third embodiment In addition to the extraction unit 23, an upper retransmission request signal generation unit 28 is provided.

Here, the higher-order retransmission request signal generation unit 28 determines the UE 5 based on the ACK / NACK error signal (ACK_NACK _error ) (see Table 4 above) extracted by the ACK / NACK erroneous determination signal extraction unit 23. When it is determined that the NACK from is erroneously determined as ACK in BS1, the upper device (eg, RNC or gateway node) holding the target downlink data, or the upper function corresponding thereto (eg, This is a request for retransmission of downlink data corresponding to an erroneous determination or downlink data including the same by a retransmission request control signal to a radio control unit built in BS1.

This is a countermeasure against the loss of downlink data that occurs when the UE 5 erroneously determines ACK even though the NACK is transmitted from the UE 5 to the BS 1.
If BS1 incorrectly determines that NACK transmitted from UE5 is ACK, BS1 transmits new data without retransmitting, and downlink data that should be retransmitted is lost without being retransmitted. This is because BS1 determines that transmission of the target downlink data is completed by receiving ACK, and deletes the downlink data stored in transmission buffer 10 in BS1.

  As a countermeasure, for example, it may be possible to determine missing data in the BS 1, but in this case, a data unit including missing data (for example, MAC-PDU (Medium Access Control-Protocol Data Unit)). (RLC-PDU (Radio Link Control-Protocol Data Unit), PDCP-PDU (Packet Data Convergence-Protocol Protocol Data Unit), etc., for example, four MAC-PDUs constitute an RLC-PDU, and four RLC-PDUs Since it becomes possible to determine data loss only after the data to be configured is arranged, and then re-transmission is performed thereafter, the time required for retransmission processing of missing data is reduced. become longer.

Therefore, in this example, when it is determined that NACK from UE5 is erroneously determined to be ACK based on the ACK / NACK error signal (ACK_NACK _error ), the higher retransmission request signal generation unit 28 makes an erroneous determination early. It is possible to request retransmission of downlink data corresponding to a host apparatus or function that holds downlink data that is the target of the transmission or downlink data including the downlink data.
The operation of the HSDPA system of this example (missing data retransmission request processing) will be described below with reference to the sequence diagram shown in FIG. 31 and the flowchart shown in FIG. However, in the following description, the host device or the host function is generically referred to as “host device 6” as shown in FIG. In FIG. 31, the sequence between BS1 and UE5 (steps S21 to S43) is the same as or similar to the sequence described with reference to FIG. 6 in the second embodiment unless otherwise specified. Next, an operation focusing on the sequence between the BS 1 and the host device 6 will be described.

As shown in FIG. 31, BS1 is transmitted from UE5 in step S42 because UE5 misdetermined as ACK even though NACK was transmitted (step S30) and newly transmitted (step S38). An ACK / NACK error signal (ACK_NACK _error ) is received (step S111 in FIG. 32).
This ACK / NACK error signal is extracted by the ACK / NACK misjudgment signal extraction unit 23 and transmitted to the transmission power control unit 25 and the higher retransmission request signal generation unit 28.

The upper retransmission request signal generation unit 28 confirms the content of the ACK / NACK error signal based on Table 4 above, and whether BS1 erroneously determines NACK as ACK (that is, whether the ACK / NACK error signal is “1100”). ) Is confirmed (step S121 in FIG. 31, step S112 in FIG. 32).
As a result, if it is determined that an erroneous determination has been made, the upper retransmission request signal generation unit 28 sends the data corresponding to the erroneous determination or the data corresponding to the erroneous determination to the upper apparatus 6 that holds the downlink data subject to the erroneous determination. A request is made to retransmit the included data (step S122 in FIG. 31, step S113 from step S112 in FIG. 32 to step S113).

That is, instead of determining whether there is data loss after the stage of arranging the data configured as described above, if it is detected that NACK is erroneously determined to be ACK, a retransmission request is immediately sent to the host device 6. Do. If NACK is not erroneously determined as ACK, no retransmission request is made to the higher-level device 6 (NO route in step S112 in FIG. 32).
If ACK / NACK is received from UE 5 (steps S123 and S124 in FIG. 31), the downlink data erroneously transmitted to UE 5 as new transmission or retransmission is stored for later retransmission (FIG. 32). Steps S114 and S115).

  When the host apparatus 6 receives the retransmission request from BS1, it performs transmission in units of data including missing data or missing data to BS1 (step S126 in FIG. 31, step S117 in FIG. 32). Preferably, the retransmission is performed with the highest priority. In addition to this, for example, it is possible to implement control such as setting the highest priority for transmission of the target retransmission data and setting the highest priority.

In FIG. 31, during this time, UE5 performs CQI measurement and transmission based on the pilot signal from BS1 (steps S125, S127, and S128).
Now, when BS1 receives the downlink data retransmitted from the higher level device 6 (step S116 in FIG. 32), the scheduler 20 performs scheduling for the downlink data (step S129 in FIG. 31), and the downlink control channel. After transmitting (HS-SCCH) (step S130 in FIG. 31), the downlink data is transmitted to the target UE 5 through the downlink data channel (HS-DSCH) (step S132 in FIG. 31).

At that time, the scheduler 20 preferably treats retransmission data from the higher-level device 6 as the highest priority and preferentially selects downlink data transmission addressed to the target UE 5. In addition, retransmission is repeatedly performed on the downlink data until no NACK is received from the UE 5 (“NACK” route in step S118 in FIG. 31).
Note that the UE 5 (ACK / NACK misjudgment detection unit 56) that has received the HS-SCCH performs NDI confirmation for detection of ACK / NACK misjudgment as in step S37 described above (step in FIG. 31). S131).

Also, the order of steps S113, S114, S115, and S116 shown in FIG. 32 is not limited as long as the relationship that step S116 is performed after step S113 and step S115 is performed after step S114 is maintained. It is.
As described above, according to this example, it is possible to shorten the time (retransmission processing time) for complementing the downlink data destined for the UE 5 that has been lost. As a result, the throughput of downlink data transmission (HS-DSCH transmission) can be improved.

[12] Twelfth Embodiment (Continuation of ACK / NACK transmission power correction)
In the first to tenth embodiments described above, the ACK / NACK transmission power control when an ACK / NACK misjudgment occurs has been described. In the present embodiment, control of ACK / NACK transmission power is described so that ACK / NACK misjudgment does not occur.

That is, in the first to tenth embodiments described above, whether or not an ACK / NACK misjudgment has occurred is determined based on the process number and NDI, but whether or not an ACK / NACK misjudgment has occurred is determined. It is also possible to perform ACK / NACK transmission power control without performing it.
For example, as in the seventh embodiment, the ACK / NACK transmission power correction value is calculated from the first ACK / NACK transmission power value and the second ACK / NACK transmission power value. ACK / NACK transmission power control is performed.

That is, after the first ACK / NACK transmission after line connection, the ACK / NACK transmission power control of the first to tenth embodiments described above is continuously performed regardless of the presence or absence of ACK / NACK misjudgment. It is possible.
Hereinafter, specific examples will be described with reference to FIGS. 33 and 34. FIG.
(Specific example 1)
As shown in FIG. 33, it is assumed that a radio channel is established between BS1 and UE5, and the first downlink data transmission is performed with process number = 1. In that case, UE5 (transmission power control part 57) implements ACK / NACK transmission power correction | amendment # 1. At this time, it does not matter whether ACK / NACK is erroneously determined.

Subsequently, the UE 5 (the transmission power control unit 57 or the retransmission control unit 58a) uses the ACK / NACK transmission power correction # 1 with the previous process number = 1 for the ACK / NACK transmission for the downlink data transmission with the process number = 2. Then, ACK / NACK transmission power correction # 2 is performed.
Thereafter, the UE 5 (transmission power control unit 57 or retransmission control unit 58a) similarly performs ACK / NACK for downlink data transmission with process number = x−1 for ACK / NACK transmission for downlink data transmission with process number = x. Based on transmission power correction # x-1, ACK / NACK transmission power correction #x is performed.

Note that the first ACK / NACK transmission power correction # 1 can be performed using a predetermined initial value. In addition, ACK / NACK transmission power correction # 1 may not be performed for ACK / NACK transmission for the first downlink data transmission.
(Specific example 2)
For example, as shown in FIG. 34, for the first ACK / NACK transmission power correction # 1, ACK / NACK transmission power correction is performed using a predetermined initial value regardless of the presence or absence of ACK / NACK misjudgment. Thereafter, for downlink data transmission of a process number (for example, process number = 2, 4) in which an ACK / NACK misjudgment has occurred, ACK / NACK based on the previous ACK / NACK transmission power correction # X-1 It is also possible to perform transmission power correction #X. For downlink data transmission of a process number (for example, process number = 3) in which no ACK / NACK misjudgment has occurred, the previous ACK / NACK transmission power correction #x is maintained.

As described above, the transmission characteristics of ACK / NACK can be improved, and the occurrence rate of ACK / NACK misjudgment can be reduced. Further, it is possible to improve the downlink throughput.
[13] Thirteenth Embodiment (CQI transmission power control)
In the HSDPA system described in the first to ninth embodiments, an uplink dedicated control channel (HS-DPCCH) that is an uplink radio channel is used for uplink ACK / NACK transmission from the UE 5 to the BS 1. This HS-DPCCH is used not only for uplink ACK / NACK transmission, but also for reporting CQI, which is an indicator of downlink radio channel quality, from UE 5 to BS 1.

Therefore, the transmission power control (correction) described in the first to ninth embodiments can be applied to CQI transmission from the UE 5 to the BS 1.
That is, as described in the first to ninth embodiments, when ACK / NACK misjudgment occurs and ACK / NACK transmission power control is performed, the transmission characteristics of CQI transmitted using the same HS-DPCCH are also It can be judged that it has deteriorated.

Therefore, when an ACK / NACK misjudgment occurs (when an ACK / NACK misjudgment detection unit 56 detects an ACK / NACK misjudgment), the UE 5 (transmission power control unit 57 or retransmission control unit 58a) The transmission power correction in the first to ninth embodiments is also performed at the time of CQI transmission to BS1.
That is, when detecting erroneous ACK / NACK determination, UE 5 corrects ACK / NACK transmission power and corrects transmission power of other information (CQI) transmitted to BS 1.

As a result, not only ACK / NACK but also CQI transmission characteristics can be improved.
In BS1, the possibility that the target UE 5 is selected in the scheduling process by the scheduler 20 is increased. Since the possibility of selection increases, the throughput of downlink data transmission is improved.

The transmission power correction described in the first to ninth embodiments may be applied to both ACK / NACK transmission and CQI transmission as described above, or may be selectively applied to either one. That is, it may be applied only to CQI transmission.
In other words, the transmission power correction described in the first to ninth embodiments can be applied to any information that is transmitted to BS1 using HS-DPCCH that is an uplink dedicated control channel.

[14] Fourteenth Embodiment (Application to Enhanced HSDPA System)
In the enhanced HSDPA system (see Non-Patent Documents 5, 6, 7, and 8), as described above with reference to FIG. 44, pre / post signals are inserted before and after the ACK / NACK signal. The first to twelfth embodiments described above can be applied to such an enhanced HSDPA system.

  FIG. 35 is a block diagram showing the configuration of a radio terminal (UE) according to the fourteenth embodiment of the present invention. For example, the UE 5 shown in FIG. 35 and, for example, FIG. 4 or FIG. 7 or FIG. 10 or FIG. A radio communication system (enhanced HSDPA system) is configured with BS 1 having the same configuration as that shown. In this example, there may be a plurality of BS1 and UE5.

  The UE 5 shown in FIG. 23 is the same as or similar to that in the UE 5 shown in FIG. 5 in the second embodiment, respectively, an antenna 51, a reception radio unit 52, a despreading unit 53a, a demodulation unit 53, and a decoding unit. Unit 54, control signal extraction unit 55, ACK / NACK misjudgment detection unit 56, transmission power control unit 57, encoding unit 59, modulation unit 60, spreading unit 60a, transmission radio unit 61, A CQI measurement unit 62 and a CQI signal generation unit 63 are provided, and an ACK / NACK (Pre / Post) signal generation unit 58c is provided instead of the ACK / NACK signal generation unit 58 described above.

  Here, the ACK / NACK (Pre / Post) signal generation unit 58c determines that the CRC confirmation result (CRC calculation result) by the error detection unit 58b is OK if there is no error, and determines that the ACK signal has an error. 44, a NACK signal is generated based on the determination, and as shown in FIG. 44, a function of inserting (adding) a Pre signal before and a Post signal after the ACK / NACK signal is provided.

Therefore, UE5 transmits, to BS1, an ACK / NACK signal obtained by adding a Pre / Post signal before and after the downlink data received from BS1 by the ACK / NACK (Pre / Post) signal generation unit 58c.
On the other hand, in BS1, the ACK / NACK extraction unit 18 extracts the ACK / NACK signal and the Pre / Post signal, and the retransmission control unit 19 based on these signals, for example, the ACK shown in Table 2 above. / NACK is determined.

That is, the addition of the Pre / Post signal to the ACK / NACK signal has no effect on the ACK / NACK transmission power correction operation described in the first to twelfth embodiments.
Therefore, it is possible to improve the accuracy of ACK / NACK determination, and reduce the occurrence rate of ACK / NACK misjudgment in combination with the improvement of the transmission characteristics of ACK / NACK by correcting the ACK / NACK transmission power described above. Can do.

[15] Fifteenth Embodiment (Application Example 1 to HSUPA System)
The HSUPA system realizes upstream high-speed packet communication. That is, high-speed transmission is realized by newly providing an E-DPCH (Enhanced-Dedicated Physical CHannel) obtained by packetizing the uplink (UL) DPCH and increasing the speed (for example, see Non-Patent Documents 5, 6, 7, and 8 above). ).

  FIG. 36 shows a configuration example of the HSUPA system. As shown in FIG. 36, the downlink radio channels from BS1 to UE5 in the HSUPA system include common pilot channel (CPICH), downlink (DL) DPCH, E-HICH (E-DCH-Hybrid ARQ Indicator CHannel), E There are -RGCH (E-DCH Relative Grant Channel) and E-AGCH (E-DCH Absolute Grant Channel), and uplink radio channels include uplink (UL) DPCH and E-DPCH.

  The E-HICH is a channel used for transmission of a downlink individual control signal for uplink data transmission, and a downlink ACK / NACK signal for uplink data is transmitted using the E-HICH. The E-RGCH is a channel used to notify a relative value (UP / DOWN) of uplink radio resources (transmission speed and transmission power) allocated to the UE 5, and the E-AGCH is an uplink radio allocated to the UE 5. This channel is used to notify the absolute value of a resource.

In the first to fourteenth embodiments, the transmission power correction of the uplink ACK / NACK signal (uplink individual control signal) for downlink data transmission has been described. Here, the transmission power of the downlink individual control signal for uplink data transmission is described. The correction will be described using an HSUPA system as shown in FIG. 36 as an example.
FIG. 37 is a block diagram showing a configuration of a radio base station (BS) according to the fifteenth embodiment of the present invention, and FIG. 38 is a block diagram showing a configuration of a radio terminal (UE) according to the fifteenth embodiment of the present invention. Thus, the HSUPA system is configured by the BS 1 and the UE 5 shown in FIG. 37 and FIG. In this example, there may be a plurality of BS1 and UE5.

(Description of BS)
The BS1 shown in FIG. 37 is the same as or similar to that in the BS1 shown in FIG. 4 in the second embodiment, for example, a transmission buffer 10, an encoding unit 11, a modulation unit 12, a spreading unit 12a, In addition to a transmission radio unit 13, an antenna 14, a reception radio unit 15, a despreading unit 16a, a demodulation unit 16, a decoding unit 17, a scheduler 20, and a control signal generation unit 21, uplink pilot power measurement A unit 29, an ACK / NACK signal generation unit 30, a control signal extraction unit 31, an ACK / NACK misjudgment detection unit 32, and a transmission power control unit 33 are provided.

  Here, the uplink pilot power measuring unit 29 measures the received power of the pilot signal component transmitted on the uplink dedicated channel (DPCH) from the despreading result in the despreading unit 16a, and based on the measurement result A function for obtaining an uplink CQI, which is an index of uplink radio channel quality, is provided. The obtained CQI is used as a reference for selecting the target UE 5 for uplink data transmission in the scheduler 20.

  The ACK / NACK signal generation unit 30 confirms the CRC of the result obtained by decoding the uplink data received from the UE 5 by the decoding unit 17, and determines that the result (CRC operation result) is OK if there is no error, and the ACK signal If there is an error, it is judged as NG and a NACK signal is generated. The generated ACK / NACK signal is subjected to predetermined processing by the encoding unit 11, the modulation unit 12, the spreading unit 12a, and the transmission radio unit 13, and then transmitted from the antenna 14 to the UE 5 by E-HICH. Is done.

  The control signal extraction unit 31 extracts an uplink control signal from the decoding result by the decoding unit 17, and the ACK / NACK erroneous determination detection unit 32 transmits the ACK / NACK information transmitted to the UE 5 and the uplink received from the UE 5. Based on the signal (including the uplink data and the control signal extracted by the control signal extraction unit 31), it is determined (detected) whether ACK or NACK transmitted from the BS1 to the UE5 is erroneously determined as NACK or ACK. )

  For detection of this ACK / NACK misjudgment, RSN (Retransmission Sequence Number) (control signal) transmitted from the UE 5 accompanying uplink data (E-DPCH) can be used. That is, since the RSN is information for counting the number of times of retransmission processing, for example, if the RSN of the received data increases even though the BS1 has transmitted ACK, it can be determined that it is erroneously determined as NACK. If the RSN of the received data is the initial value (for example, 0) or has not increased even though the BS 1 has transmitted a NACK, it can be determined that the ACK is erroneously determined.

  The transmission power control unit 33 has a function equivalent to the transmission power control unit 57 (or retransmission control unit 58a) in the UE 5 described above, and the ACK / NACK erroneous determination detection unit 32 detects the occurrence of an ACK / NACK erroneous determination. Then, it controls (corrects) the transmission power of E-HICH in which downlink ACK / NACK to UE5 is transmitted. At this time, preferably, a correction method equivalent to the correction method performed in uplink ACK / NACK transmission in the above-described embodiment is applied.

(Description of UE)
On the other hand, the UE 5 shown in FIG. 38 is the same as or similar to that in the BS 1 shown in FIG. 4 in the second embodiment, for example, the antenna 51, the reception radio unit 52, the despreading unit 53a, and the demodulation unit 53. A decoding unit 54, a control signal extraction unit 55, a transmission power control unit 57, an encoding unit 59, a modulation unit 60, a spreading unit 60a, and a transmission radio unit 61, and an ACK / NACK extraction. A unit 67 and a transmission / retransmission control unit 68 are provided.

  Here, the ACK / NACK extraction unit 67 extracts the downlink ACK / NACK received from the BS 1 by E-HICH from the decoding result in the decoding unit 54, and the transmission / retransmission control unit 68 / NACK extractor 67 controls uplink transmission to BS1 according to ACK / NACK extracted. If ACK is received and extracted, new uplink data is transmitted, and NACK is received and extracted. Then, the transmitted uplink data is retransmitted. In FIG. 38, the uplink data is buffered in the transmission buffer 10 in preparation for retransmission.

(Description of operation)
Hereinafter, the operation (downlink ACK / NACK transmission power control) of the HSUPA system configured as described above will be described with reference to the sequence diagram shown in FIG.
As shown in FIG. 39, UE5 repeatedly transmits an uplink pilot signal to BS1 periodically or irregularly on uplink DPCH (steps S141 and S150).

  When the BS 1 receives the uplink pilot signal, the uplink pilot power measurement unit 29 obtains the received power, and obtains the uplink CQI based on the received power. The uplink CQI is transmitted to the scheduler 20, and the scheduler 20 uses the uplink CQI to select the UE 5 that grants the uplink transmission permission, and the uplink transmission timing and transmission method (coding rate, modulation) for the UE 5 System) is determined (steps S142 and S151). Information (scheduling information) such as the selected UE 5, uplink transmission timing, and transmission method is transmitted to the control signal generation unit 21.

  The control signal generator 21 generates a control signal including the scheduling information received from the scheduler 20. The control signal is subjected to predetermined processing by the encoding unit 11, the modulation unit 12, the spreading unit 12a, and the transmission radio unit 13, respectively, and then the downlink individual control signal (for example, E-DPCCH or E -AGCH signal) is transmitted to the UE 5 (steps S143 and S152).

UE5 extracts the said downlink separate control signal in the control signal extraction part 55, and implements uplink data transmission with respect to BS1 based on the control signal. That is, the uplink data is transmitted to BS1 by E-DPCH at the uplink transmission timing and transmission method specified by the control signal (steps S144 and S153).
The BS 1 that has received the first E-DPCH signal from the UE 5 uses the ACK / NACK signal generation unit 30 to check the CRC and RSN of the received uplink data, and determines whether there is an error. If there is an error, a NACK is generated and transmitted to UE 5 by E-HICH (steps S145, S146, S148).

Here, the transmission power control of E-HICH is described in Non-Patent Document 8 only as it is described that it is implemented by a control signal transmitted from UE5 or by power control performed by BS1. It is not specified until.
Therefore, for example, as in the HS-DPCCH transmission power control in HSDPA, the ACK / NACK transmission power value P _{ACK / NACK} is determined by the downlink DPCH transmission power value P _{DL_DPCH} and the E-HICH transmission power offset value P _{E-HICH_offset} . It is assumed that it is calculated (step S147), and the following equation (35) is assumed. This satisfies the description of Non-Patent Document 8 described above.

Further, the offset value P _{E-HICH_offset} may be fixed to 0.5 (dB) as shown in the following expressions (36) and (37), for example, as in the second embodiment. However, different offset values P _{E-HICH_offset} may be set for ACK and NACK.

  When the UE 5 receives ACK from the BS 1 by E-HICH, the transmission / retransmission control unit 68 performs new uplink data transmission, and when NACK is received, the UE 5 retransmits the transmitted target uplink data. -Implement on DPCH (steps S148, S149, S153). However, the E-DPCH can be transmitted when the UE 5 receives the control signal (uplink transmission permission) through the E-AGCH (step S152).

  When the BS 1 receives the E-DPCH signal, the control signal extraction unit 31 extracts the RSN and notifies the ACK / NACK erroneous determination detection unit 32. Based on the ACK / NACK information transmitted to the UE 5 last time and the RSN, the ACK / NACK erroneous determination detection unit 32 determines whether or not there is an ACK / NACK erroneous determination, that is, the ACK or NACK transmitted by the BS 1 It is confirmed whether or not it is erroneously determined as ACK (steps S154 and S155).

As a result, if an ACK / NACK misjudgment is detected, the BS 1 corrects (controls) the transmission power of the ACK / NACK by the transmission power control unit 33 (step S156). At that time, for example, as shown in the following equation (38), the downlink DPCH transmission power value P _UL-DPCH , the offset value P _{E-HICH_offset,} and the ACK / NACK transmission power correction value P _{E-HICH_c} are added. it is, calculates the transmission power value P '' _{ACK / NACK} of the downlink ACK / NACK transmission (step S157) (step S156).

Here, the correction value P _{E-HICH_c} may be fixed to 0.5 (dB) as shown in the following equations (39) and (40), for example. However, as in the second embodiment, a negative value of −0.5 (dB) may be set.

  As described above, it becomes possible to improve the transmission characteristics in the ACK / NACK return from BS1 to UE5 after determining that ACK received by UE5 from BS1 is wrong as NACK or NACK as ACK. It is possible to reduce the probability of misidentifying transmitted ACK as NACK or NACK as ACK (step S158). As a result, useless downlink transmission can be reduced, and throughput can be improved.

In addition, since it is not necessary to add the above-described Pre / Post signal, it is possible to reduce the power required for transmission and to reduce power consumption.
It should be noted that the third and / or fourth embodiments can be applied to the HSUPA system of this example. That is, an ACK / NACK error signal may be transmitted from BS1 that has detected an ACK / NACK misjudgment to UE5, and an offset correction value may be notified to BS1 based on a downlink signal of another BS1.

Also, it is possible to apply the transmission power control (correction) of other embodiments to a downlink individual control signal for uplink data transmission.
[16] Sixteenth Embodiment (Application Example 2 to HSUPA System)
FIG. 40 is a block diagram showing a configuration of a radio base station (BS) according to the sixteenth embodiment of the present invention. The HSUPA system is configured by the BS 1 shown in FIG. 40 and the UE 5 shown in FIG. 38, for example. In this example, there may be a plurality of BS1 and UE5.

The BS 1 shown in FIG. 40 is different from the configuration of the BS 1 shown in FIG. 37 in that the uplink pilot power storage unit 34 is further provided.
Here, the uplink pilot power storage unit 34 stores the uplink pilot power value measured by the uplink pilot power measurement unit 29. The stored contents can be appropriately referred (read) by the scheduler 20 and used as selection criteria for the UE 5 to be received by the scheduler 20.

Then, the transmission power control unit 33 of the present example cooperates with the scheduler 20 to store the difference in the uplink pilot power value (uplink pilot power difference) stored in the uplink pilot power storage unit 34 when receiving multiple uplink DPCHs. Is provided with a function of calculating the fluctuation of the propagation environment based on the above and performing downlink ACK / NACK transmission power control (correction) according to the difference.
For example, if the uplink pilot power difference exceeds a predetermined threshold, the propagation environment changes (deteriorates) greatly, so that the transmission power control unit 33 performs ACK / NACK misjudgment in normal E-HICH transmission power control. Therefore, downlink ACK / NACK (E-HICH) transmission power control (correction) corresponding to the uplink pilot power difference is performed.

On the other hand, if the uplink pilot power difference is equal to or less than a predetermined threshold, the transmission power control unit 33 has a small fluctuation (degradation) of the propagation environment, so that even in normal E-HICH transmission power control, ACK / NACK misjudgment Therefore, the ACK / NACK (E-HICH) transmission power value is maintained at the previous power value.
As described above, according to the present embodiment, when a downlink ACK / NACK transmission error occurs, the BS 1 determines a change in the propagation environment based on the uplink pilot power, and performs downlink ACK / NACK transmission according to the change. Control (correct) transmission power.

Therefore, the same effects and advantages as those of the fifteenth embodiment can be obtained, and the ACK / NACK transmission characteristics can be further improved to reduce the occurrence rate of ACK / NACK misjudgment.
[17] Seventeenth Embodiment (Application to HSPA system)
In short, the HSPA system corresponds to a system in which the HSDPA system and the HSUPA system are integrated. Therefore, the above-described first to thirteenth embodiments can be applied to uplink ACK / NACK transmission and downlink ACK / NACK transmission.

  Note that the configuration of the BS (UE) in the HSDPA system corresponds to a configuration in which the functions of the BS (MS) in each system are combined. The processing sequence focused on uplink ACK / NACK transmission power control (correction) is the same as that in the second embodiment (FIG. 6), and the processing sequence focused on downlink ACK / NACK transmission power control (correction) is the 15th. This is the same as the embodiment (FIG. 39). Therefore, the effects and advantages described in each system can be obtained.

  However, in the HSPA system, uplink CQI and downlink CQI are aggregated in BS1, so uplink CQI can be used for uplink ACK / NACK transmission power control. Therefore, since the uplink propagation environment can be estimated with higher accuracy than in the case of using the downlink CQI, it is more accurate than the uplink ACK / NACK transmission power control using the downlink CQI described in the fifth embodiment. Power control is possible.

Note that either or both of uplink and downlink ACK / NACK transmission power can be controlled using both uplink CQI and downlink CQI (for example, average).
[18] Eighteenth Embodiment (Application Example to LTE System)
The LTE system is a system that has been studied in 3GPP as a next-generation mobile communication system. Like the HSDPA system and the HSUPA system, packet transmission is performed and ACK / NACK transmission is performed for packet transmission. (Refer to said nonpatent literature 9,10,11).

  Here, in the LTE system, the multiplexing method is different compared to the HSDPA system and the HSUPA system. That is, while the HSDPA system and the HSUPA system employ a CDMA system, the LTE system employs an OFDMA (or OFDM) system for uplink and SC (Single Carrier) -FDMA for downlink. For this reason, the LTE system does not require spreading processing and despreading processing in the CDMA system, and uses FFT processing and IFFT processing.

Hereinafter, an example in which the above-described ACK / NACK transmission power control (correction) (for example, the second embodiment) is applied to the LTE system will be described.
FIG. 41 shows a configuration example of a radio base station (BS) in the LTE system according to the eighteenth embodiment of the present invention, and FIG. 42 shows a configuration example of radio terminals (UE) in the LTE system according to the eighteenth embodiment of the present invention. Respectively.

(Description of BS)
41 includes, for example, a transmission buffer 10, an encoding unit 11, a modulation unit 12, a serial / parallel (S / P) converter 12b, an IFFT (Inverse Fast Fourier Transformer) 12c, a parallel / Serial (P / S) converter 12d, guard interval (GI) insertion unit 12e, transmission radio unit 13, antenna 14, reception radio unit 15, GI removal unit 16b, S / P converter 16c , FFT (Fast Fourier Transformer) 16d, P / S converter 16e, demodulator 16, decoder 17, ACK / NACK extractor 18, retransmission controller 19, scheduler 20, and control signal generator 21, a CQI extraction unit 22, an uplink pilot power calculation unit 24, and a transmission power control unit 25.

  Here, the description will be made focusing on the characteristic function as BS1 in the LTE system. In the transmission system, the S / P converter 12b is a signal (downlink) encoded by the encoding unit 11 and modulated by the modulation unit 12. Signal) is serial / parallel converted into parallel data (symbols) corresponding to the number of subcarriers. The parallel data (subcarrier signal) is input to the IFFT 12c having a predetermined number of points (512, etc.) and mapped, so that the frequency domain is arranged.

The IFFT 12c converts the frequency domain signal into a time domain signal by performing IFFT processing on the subcarrier signal.
The P / S converter 12d performs parallel / serial conversion on the output of the IFFT 12c and outputs it in time series.
The GI insertion unit 12e inserts (adds) a guard interval (cyclic prefix) in units of a predetermined symbol (OFDM symbol) to the output of the P / S converter 12d. For example, a part of each OFDM symbol after IFFT processing is cyclically copied and inserted (added) as a cyclic prefix (CP) at the head of each OFDM symbol. This CP serves as a guard interval for reducing intersymbol interference.

  On the other hand, in the reception system, the GI removal unit 16b is inserted (added) in the same manner as described above with respect to the transmission signal (symbol) on the UE 5 side from the uplink signal processed by the reception radio unit 15. And the effective signal component of the received symbol (the number of samples subject to FFT of a predetermined number of points) is extracted. The start timing of the effective signal component extraction interval (FFT window) can be detected based on the correlation between the received signal and the uplink pilot signal replica (pilot replica).

The S / P converter 16c performs serial / parallel conversion of the effective signal component from the GI removing unit 16b into parallel data having the number of FFT points in the FFT 16d.
The FFT 16d obtains a reception signal for each subcarrier signal component by performing FFT processing for the number of FFT points on the parallel data and converting the parallel data into a signal from the time domain to the frequency domain.

The P / S converter 16e performs parallel / serial conversion on the subcarrier signal obtained by the FFT 16d and outputs it in time series. The output signal is input to the demodulator 16 and the uplink pilot power calculator 24.
With the above configuration, the BS 1 can correctly transmit the downlink signal and receive the uplink signal in accordance with the OFDMA scheme, and the ACK / NACK extraction unit 18 extracts the uplink ACK / NACK transmitted by the UE 5, Retransmission control according to the ACK / NACK can be performed by the retransmission control unit 19.

(Description of UE)
On the other hand, the UE 5 shown in FIG. 42 includes, for example, an antenna 51, a reception radio unit 52, a GI removal unit 53b, an S / P converter 53c, an FFT 53d, a P / S converter 53e, and a demodulation unit 53. A decoding unit 54, a control signal extraction unit 55, an ACK / NACK error determination detection unit 56, a transmission power control unit 57, an ACK / NACK signal generation unit 58, a retransmission control unit 58a, and an error detection unit 58b. An encoding unit 59, a modulation unit 60, an S / P converter 60b, an IFFT 60c, a P / S converter 60d, a transmission radio unit 61, a CQI measurement unit 62, and a CQI signal generation unit 63. I have it.

  Here, similarly to BS1, the description will be made focusing on the characteristic function as UE1 in the LTE system. In the reception system, the GI removal unit 53b is the reception radio unit 52 in the same manner as the GI removal unit 16b on the BS1 side. The effective signal component is extracted by removing the GI inserted by the BS1 (GI insertion unit 12e) from the processed downlink signal. The start timing of the effective signal component extraction interval (FFT window) in the UE 5 can be detected based on the correlation between the received signal and the downlink pilot replica.

The S / P converter 53c, like the BS1 side S / P converter 16c, serial / parallel converts the effective signal component from the GI removal unit 53b into parallel data of the number of FFT points in the FFT 53d. is there.
Similar to the FFT 16d on the BS1 side, the FFT 53d performs FFT processing for the number of FFT points on the parallel data to convert the signal from the time domain to the frequency domain, thereby converting the received signal for each subcarrier signal component. To get.

The P / S converter 53e, like the BS1 P / S converter 16e, performs parallel / serial conversion on the subcarrier signal obtained by the FFT 16d and outputs it in time series. The output signal is input to the demodulation unit 53 and the CQI measurement unit 62.
On the other hand, in the transmission system, the S / P converter 60b converts the signal (uplink signal) encoded by the encoding unit 59 and modulated by the modulation unit 60 into the same manner as the S / P converter 12b on the BS1 side. Serial / parallel conversion is performed on parallel data (symbols) corresponding to the number of subcarriers. Also in the UE 5, the parallel data (subcarrier signal) is input to the IFFT 53c having a predetermined number of points (512, etc.) and mapped, so that the frequency domain is arranged.

Similarly to the IFFT 12c on the BS1 side, the IFFT 60c converts the frequency domain signal into a time domain signal by performing an IFFT process on the subcarrier signal.
The P / S converter 60d performs parallel / serial conversion on the output of the IFFT 60c and outputs it in time series, like the BS / P converter 12d on the BS1 side.

The GI insertion unit 60e inserts (adds) a guard interval (cyclic prefix) in units of a predetermined symbol (OFDM symbol) to the output of the P / S converter 60d, similarly to the GI insertion unit 12e on the BS1 side. )
With the above configuration, the UE 5 can correctly transmit an uplink signal and receive a downlink signal in conformity with the OFDMA scheme, and returns an ACK / NACK response to the BS 1 for downlink received data, CQI measurement, report, and reception from the BS 1 The processing according to the control signal thus performed can be appropriately performed.

  In addition, when an ACK / NACK misjudgment detection unit 56 detects an ACK / NACK misjudgment, the transmission power control unit controls (corrects) the uplink ACK / NACK transmission power in the same manner as the above-described embodiment. 57. The processing sequence is the same as that of the second embodiment (FIG. 6), for example. Also, downlink ACK / NACK transmission can be applied in the same manner as in the HSUPA system.

  In the LTE system, there is a concern that interference from other cells becomes larger than that in the HSDPA system due to the difference in the multiplexing method. Therefore, the uplink ACK / NACK transmission characteristics may be deteriorated compared to the HSDPA system, and the occurrence rate of ACK / NACK misjudgment may increase. Therefore, it is useful to implement the ACK / NACK transmission power control (correction) in the LTE system.

Further, in the LTE system, there is no dedicated channel as in the HSDPA system and the HSUPA system. As in the above-described embodiment, assuming that the ACK / NACK transmission power value is controlled based on the transmission power control value of the dedicated channel, there is a possibility that the LTE system cannot perform the same control.
However, since the power control using the individual DPCH described above is performed using the DPCCH constituting the DPCH, there is no problem as long as there is at least a channel corresponding to the DPCCH. Even if DPCH does not exist, the same power control is possible using a channel corresponding to this, for example, CCCH (Common Control CHannel) under study in 3GPP.

In the LTE system, since both uplink and downlink are packet transmissions, it is possible to improve the accuracy of ACK / NACK transmission power control using CQI as in the application to the HSPA system described above.
That is, the first to sixteenth embodiments can be applied to uplink ACK / NACK transmission and downlink ACK / NACK transmission, and the same effects or advantages as those can be obtained.

[19] Nineteenth embodiment (variable ACK / NACK transmission power offset step)
As described in the first embodiment, after performing ACK / NACK transmission power control, if an ACK / NACK misjudgment is detected again (ACK / NACK transmission characteristics are not improved), a transmission power control unit 25 and 57 can control the current transmission power value with a control amount larger than the control amount (step width) of the previous transmission power value.

  For example, when the ACK / NACK transmission power correction value (step width) is initially 0.5 dB and an ACK / NACK misjudgment occurs again even if ACK / NACK is transmitted with the corrected ACK / NACK transmission power Then, the step width is increased by 0.5 dB, and ACK / NACK is transmitted at 1.0 dB. Thereafter, the ACK / NACK transmission power correction value is corrected until it is correctly received.

That is, the initial value of the ACK / NACK transmission power correction value is set to 0.5 dB, and thereafter the ACK / NACK transmission power correction value is varied (updated) in 0.5 dB steps every time an ACK / NACK erroneous determination occurs.
[20] 20th embodiment (ACK / NACK transmission power upper limit notification)
In the above-described embodiment, when the ACK / NACK transmission power value of the UE 5 reaches the upper limit, the UE 5 notifies the BS 1 to that effect. For example, this function may be combined with the function of the ACK / NAC error signal generation unit 64 shown in FIG. 8, or may be realized by providing the UE 5 with an individual notification signal generation unit.

  Upon receiving this notification, the BS 1 changes the transmission method such as the modulation method and the coding method used for ACK / NACK transmission to a transmission method with improved transmission characteristics, and transmits information on the transmission method to the UE 5 using a control signal. Notice. For example, the modulation method is changed to a method with a smaller multi-level number (from 16QAM to QPSK, etc.), or the coding rate is lowered (from 1/3 to 1/6, etc.) to increase the redundancy of the error correction code. Thus, transmission characteristics of ACK / NACK can be improved.

The change of the transmission method in the BS 1 can be performed, for example, by the scheduler 20 described above. Further, the notification from the UE 5 may be extracted by, for example, the ACK / NACK misjudgment signal extraction unit 23 shown in FIG. 7, or an individual notification signal extraction unit may be extracted along with the BS 1. .
And UE5 extracts the said control signal received from BS1 in the control signal extraction part 55, changes the transmission method of ACK / NACK according to the content, and transmits ACK / NACK to BS1. The change of the transmission method in the UE 5 can be realized by controlling the operations of the encoding unit 59 and the modulation unit 60. The transmission power control unit 57 or an individual control unit may control these operations.

As described above, even when the ACK / NACK transmission power value of UE5 reaches the upper limit, the transmission characteristics of uplink ACK / NACK can be improved, and the occurrence rate of ACK / NACK misjudgment at BS1 is reduced. be able to.
When the ACK / NACK transmission power value reaches the lower limit, the UE 5 may be notified to that effect and the transmission method may be changed opposite to the above.

[21] Twenty-first embodiment (UE processing when NACK is erroneously determined as ACK)
In the first to thirteenth embodiments, BS5 misidentifies NACK transmitted by UE5 as ACK, transmits new data from BS1 to UE5, and UE5 detects that NACK misidentified NACK as ACK in BS1. In this case, since the UE 5 has not received retransmission of downlink data for the NACK, the UE 5 returns a NACK to the BS 1 regardless of whether or not the received new data has an error.

That is, when the UE 5 erroneously receives an ACK even though the UE 5 has transmitted a NACK, the UE 5 requests the BS 1 to retransmit the downlink data to be processed.
Alternatively, the UE 5 may return nothing for the received new data. In that case, BS1 judges that it is NACK because nothing is returned from UE5 from UE5 for a certain period of time.

As described above, data loss when NACK is erroneously determined as ACK can be prevented.
Further, the UE 5 may determine whether there is an error in the received new data, return an ACK or NACK for the new data to the BS 1 and transmit a NACK for the previous downlink data.

At this time, preferably, an identification signal for distinguishing between ACK / NACK for the current new data and NACK for the previous downlink data is added. The ACK / NACK for the new data this time and the NACK for the previous downlink data may be transmitted by time division multiplexing, frequency division multiplexing, or code division multiplexing.
Thereby, it is possible to prevent data loss when NACK is erroneously determined as ACK, and the BS 1 and the UE 5 can proceed with processing for new data.

Note that the same control as described above is possible for downlink ACK / NACK transmission from BS1 to UE5 for uplink data.
The following supplementary notes are further disclosed with respect to the embodiments including the above examples.
[22] Appendix (Appendix 1)
A communication control method for a wireless communication system, comprising: a wireless transmission device; and a wireless reception device that transmits reception result confirmation information indicating whether or not a signal received from the wireless transmission device has an error to the wireless transmission device. And
The wireless receiver is
Whether the wireless transmission device erroneously received the first reception result confirmation information based on the first reception result confirmation information transmitted to the wireless transmission device and a signal received from the wireless transmission device thereafter Determine whether or not
According to the determination result, the transmission condition of the second reception result confirmation information to be transmitted to the wireless transmission device is controlled.
A communication control method for a wireless communication system.

(Appendix 2)
The wireless receiver is
When it is determined that the wireless transmission device has received the first reception result confirmation information in error,
Increasing the transmission power of the second reception result confirmation information;
The communication control method for a wireless communication system according to appendix 1, wherein

(Appendix 3)
The wireless receiver is
When it is determined that the wireless transmission device has received the first reception result confirmation information in error,
Changing the transmission method of the second reception result confirmation information to a transmission method whose transmission characteristics are improved;
The communication control method for a wireless communication system according to appendix 1, wherein

(Appendix 4)
The wireless receiver is
Changing the multilevel modulation scheme of the second reception result confirmation information to a modulation scheme having a small multilevel number;
The method of controlling a wireless communication system according to appendix 3, wherein
(Appendix 5)
The wireless receiver is
Control to reduce the coding rate of the second reception result confirmation information;
The method of controlling a wireless communication system according to appendix 3, wherein

(Appendix 6)
The wireless receiver is
Notifying the wireless transmission device of the determination result,
The communication control method for a wireless communication system according to appendix 1, wherein
(Appendix 7)
The wireless receiver is
Receiving from the wireless transmission device information related to interference given to transmission of reception result confirmation information by another wireless reception device or transmission power correction information based on the information by transmission power of the second reception result confirmation information;
Based on the information on the interference or the transmission power correction information, the transmission power of the second reception result confirmation information is controlled.
The communication control method for a wireless communication system according to Appendix 2, wherein

(Appendix 8)
The wireless receiver is
Based on radio channel characteristic information measured based on a signal received from the radio base station, or transmission power correction information obtained and received by the radio base station by notifying the radio base station of the radio channel characteristic information And controlling the transmission power of the second reception result confirmation information,
The communication control method for a wireless communication system according to Appendix 2, wherein

(Appendix 9)
The wireless receiver is
Comparing the first radio channel characteristic information when transmitting the first reception result confirmation information with the second radio channel characteristic information when transmitting the second reception result confirmation information;
Based on the comparison result, the transmission power of the second reception result confirmation information is controlled.
The communication control method for a wireless communication system according to appendix 5, wherein:

(Appendix 10)
The wireless receiver is
When the comparison result indicates an improvement in radio channel characteristics, the transmission power is controlled based on the second radio channel characteristic information;
When the comparison result indicates degradation of radio channel characteristics, the transmission power is controlled based on the first radio channel characteristic information;
The communication control method for a wireless communication system according to appendix 9, wherein

(Appendix 11)
The wireless receiver is
If it is determined that the wireless transmission device has received the first reception result confirmation information in error, then the transmission power of the second reception result confirmation information for each of the signals received from the wireless base station is controlled.
The communication control method for a wireless communication system according to Appendix 2, wherein

(Appendix 12)
The wireless receiver is
When it is determined that the wireless transmission device has received the first reception result confirmation information in error, the second reception result confirmation for the signal is performed only when there is an error in the signal received from the wireless base station thereafter. Control the transmission power of information,
The communication control method for a wireless communication system according to Appendix 2, wherein

(Appendix 13)
The wireless receiver is
When determining that the wireless transmission device has received the first reception result confirmation information in error, the wireless transmission device also controls transmission power of information other than the reception result confirmation information to be transmitted to the wireless transmission device.
The communication control method for a wireless communication system according to Appendix 2, wherein

(Appendix 14)
The wireless receiver is
When it is determined that the first reception result confirmation information indicating no error is erroneously received by the wireless transmission device as information indicating that there is an error, reception processing of a signal retransmitted from the wireless transmission device is performed. Stop,
The communication control method for a wireless communication system according to appendix 1, wherein

(Appendix 15)
The wireless receiver is
The transmission power is individually controlled by the second reception result confirmation information indicating that there is an error and the second reception result confirmation information indicating that there is no error.
The communication control method for a wireless communication system according to appendix 1, wherein

(Appendix 16)
The wireless receiver is
When the transmission power reaches the upper limit, the transmission method of the second reception result confirmation information is changed to a transmission method whose transmission characteristics are improved.
The communication control method for a wireless communication system according to Appendix 2, wherein

(Appendix 17)
The communication control method for a wireless communication system according to appendix 1, wherein the wireless transmission device is a wireless base station, and the wireless reception device is a wireless terminal.
(Appendix 18)
The communication control method for a wireless communication system according to appendix 1, wherein the wireless transmission device is a wireless terminal and the wireless reception device is a wireless base station.

(Appendix 19)
In the wireless reception device of a wireless communication system, comprising: a wireless transmission device; and a wireless reception device that transmits reception result confirmation information indicating whether or not a signal received from the wireless transmission device has an error to the wireless transmission device. There,
Whether the wireless transmission device erroneously received the first reception result confirmation information based on the first reception result confirmation information transmitted to the wireless transmission device and a signal received from the wireless transmission device thereafter Determining means for determining whether or not;
Control means for controlling a transmission condition of second reception result confirmation information to be transmitted to the wireless transmission device according to a determination result in the determination means;
A wireless receiver for a wireless communication system, characterized by comprising:

(Appendix 20)
The control means includes
A transmission power control unit configured to increase the transmission power of the second reception result confirmation information when the determination unit determines that the wireless transmission device has received the first reception result confirmation information in error; The radio reception apparatus in the radio communication system according to appendix 19, wherein

(Appendix 21)
The control means includes
If the determination means determines that the wireless transmission device has received the first reception result confirmation information in error, the transmission method of the second reception result confirmation information is improved as its transmission characteristics. The wireless reception device of the wireless communication system according to appendix 19, further comprising a transmission method control unit that is changed to

(Appendix 22)
The transmission method control unit
Changing the multilevel modulation scheme of the second reception result confirmation information to a modulation scheme having a small multilevel number;
The wireless receiving device of the wireless communication system according to appendix 21, wherein
(Appendix 23)
The transmission method control unit
Control to reduce the coding rate of the second reception result confirmation information;
The wireless receiving device of the wireless communication system according to appendix 21, wherein

(Appendix 24)
The control means includes
20. The wireless reception device of a wireless communication system according to appendix 19, further comprising notification means for notifying the wireless transmission device of a determination result by the determination means.
(Appendix 25)
The transmission power control unit
Based on information relating to interference given to transmission of reception result confirmation information by another wireless reception device or transmission power correction information based on the information received from the wireless device by transmission power of the second reception result confirmation information, Controlling the transmission power of the second reception result confirmation information,
The radio receiving apparatus of the radio communication system according to appendix 20, wherein

(Appendix 26)
The transmission power control unit
Based on radio channel characteristic information measured based on a signal received from the radio base station, or transmission power correction information obtained and received by the radio base station by notifying the radio base station of the radio channel characteristic information And controlling the transmission power of the second reception result confirmation information,
The radio receiving apparatus of the radio communication system according to appendix 20, wherein

(Appendix 27)
The transmission power control unit
Based on the comparison result between the first wireless channel characteristic information when transmitting the first reception result confirmation information and the second wireless channel characteristic information when transmitting the second reception result confirmation information, Controlling the transmission power of the second reception result confirmation information;
27. A radio receiving apparatus of a radio communication system according to appendix 26, wherein

(Appendix 28)
The transmission power control unit
When the comparison result indicates an improvement in radio channel characteristics, the transmission power is controlled based on the second radio channel characteristic information;
When the comparison result indicates degradation of radio channel characteristics, the transmission power is controlled based on the first radio channel characteristic information;
28. A radio receiving apparatus for a radio communication system according to appendix 27, wherein

(Appendix 29)
The transmission power control unit
When the determination means determines that the wireless transmission device has received the first reception result confirmation information in error, the second reception result confirmation information for each of the signals received from the wireless base station thereafter. Control transmit power,
The radio receiving apparatus of the radio communication system according to appendix 20, wherein

(Appendix 30)
The transmission power control unit
When the determination means determines that the wireless transmission device has received the first reception result confirmation information in error, the signal for the signal is received only when there is an error in the signal received from the wireless base station thereafter. Controlling the transmission power of the second reception result confirmation information,
The radio receiving apparatus of the radio communication system according to appendix 20, wherein

(Appendix 31)
The transmission power control unit
When the determination means determines that the wireless transmission device has received the first reception result confirmation information in error, the transmission power for transmitting other information than the reception result confirmation information to the wireless transmission device Also control,
The radio receiving apparatus of the radio communication system according to appendix 20, wherein

(Appendix 32)
The control means includes
When the determination means determines that the first reception result confirmation information indicating no error is erroneously received as information indicating that there is an error, the first transmission result confirmation information has been retransmitted from the wireless transmission device. Item 20. The radio reception apparatus for a radio communication system according to appendix 19, further comprising reception control means for stopping signal reception processing.

(Appendix 33)
The transmission power control unit
The transmission power is individually controlled by the second reception result confirmation information indicating that there is an error and the second reception result confirmation information indicating that there is no error.
The radio receiving apparatus of the radio communication system according to appendix 20, wherein

(Appendix 34)
The control means includes
Supplementary note 19 comprising a transmission method control unit that changes the transmission method of the second reception result confirmation information to a transmission method whose transmission characteristics are improved when the transmission power reaches an upper limit. A wireless receiver of the wireless communication system described.

1 Radio base station (BS)
DESCRIPTION OF SYMBOLS 10 Transmission buffer 11 Coding part 12 Modulation part 12a Spreading part 13 Transmission radio part 14 Antenna 15 Reception radio part 16 Demodulation part 16a Despreading part 17 Decoding part 18 ACK / NACK extraction part 19 Retransmission control part 20 Scheduler 21 Control signal generation part 22 CQI extraction unit 23 ACK / NACK misjudgment signal extraction unit 24 uplink pilot power calculation unit 25 transmission power control unit 26 interference measurement unit 27 CQI storage unit 28 upper retransmission request signal generation unit 29 uplink pilot power measurement unit 30 ACK / NACK signal Generation unit 31 Control signal extraction unit 32 ACK / NACK erroneous determination detection unit 33 Transmission power control unit 34 Uplink pilot power storage unit 5 Radio terminal (UE)
51 Antenna 52 Reception Radio Unit 53 Demodulation Unit 53a Despreading Unit 54 Decoding Unit 55 Control Signal Extraction Unit 56 ACK / NACK Error Determination Detection Unit 57 Transmission Power Control Unit 58 ACK / NACK Signal Generation Unit 58a Retransmission Control Unit 58b Error Detection Unit 58c ACK / NACK (Pre / Post) signal generation unit 59 Coding unit 60 Modulation unit 60a Spreading unit 61 Transmission radio unit 62 CQI measurement unit 63 CQI signal generation unit 64 ACK / NACK error signal generation unit 65 CQI storage unit 66 ACK / NACK Transmission power storage unit

Claims (4)

A communication control method for a wireless communication system, comprising: a base station device; and a terminal device that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the base station device to the base station device. ,
The terminal device
Whether the base station apparatus erroneously received the first reception result confirmation information based on the first reception result confirmation information transmitted to the base station apparatus and the signal received from the base station apparatus thereafter Determine whether or not
When the base station apparatus determines that the first reception result confirmation information has been received in error, the transmission power of the second reception result confirmation information to be transmitted to the base station apparatus is increased and the transmission power is limited to an upper limit. The second reception result confirmation information transmission method is changed to a transmission method that improves the transmission characteristics of the second reception result confirmation information.
A communication control method for a wireless communication system. A communication control method for a wireless communication system comprising a terminal device and a base station device that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the terminal device, to the terminal device,
The base station device
Whether or not the terminal device has erroneously received the first reception result confirmation information based on the first reception result confirmation information transmitted to the terminal device and a signal received from the terminal device thereafter. Judgment,
If it is determined that the terminal device has received the first reception result confirmation information in error, the transmission power of the second reception result confirmation information to be transmitted to the terminal device is increased and the transmission power reaches the upper limit. Then, the transmission method of the second reception result confirmation information is changed to a transmission method that improves the transmission characteristics of the second reception result confirmation information.
A communication control method for a wireless communication system. A terminal device of a wireless communication system, comprising: a base station device; and a terminal device that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the base station device, to the base station device. ,
Whether the base station apparatus erroneously received the first reception result confirmation information based on the first reception result confirmation information transmitted to the base station apparatus and the signal received from the base station apparatus thereafter Determining means for determining whether or not;
When the determination means determines that the base station apparatus has received the first reception result confirmation information in error, the transmission power of the second reception result confirmation information to be transmitted to the base station apparatus is increased. Control means for changing the transmission method of the second reception result confirmation information to a transmission method in which transmission characteristics of the second reception result confirmation information are improved when the transmission power reaches an upper limit;
A terminal device of a wireless communication system, characterized by comprising: The base station apparatus of a wireless communication system comprising a terminal apparatus and a base station apparatus that transmits reception result confirmation information indicating whether or not there is an error in a signal received from the terminal apparatus, to the terminal apparatus,
Whether or not the terminal device has erroneously received the first reception result confirmation information based on the first reception result confirmation information transmitted to the terminal device and a signal received from the terminal device thereafter. Determination means for determining;
When the determination unit determines that the terminal device has received the first reception result confirmation information in error, the transmission power of the second reception result confirmation information to be transmitted to the terminal device is increased, Control means for changing the transmission method of the second reception result confirmation information to a transmission method that improves the transmission characteristics of the second reception result confirmation information when the transmission power reaches an upper limit;
A base station apparatus for a wireless communication system, comprising:

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