Abstract:
A wireless apparatus includes a wireless unit to convert a wireless signal received by an antenna into a baseband signal; and a baseband processing apparatus to receive a packet corresponding to the baseband signal via a communication line connected with the wireless unit, to detect an error in a transmission process of the packet via the communication line, to obtain the baseband signal based on packets other than the packet in which the error is detected, to generate transmission power information used for downlink transmission power control based on the obtained baseband signal, to transmit the baseband signal having the generated transmission power information reflected to the wireless unit via the communication line, and to have the wireless unit execute wireless transmission of a wireless signal corresponding to the baseband signal having the transmission power information reflected.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of International Application PCT/JP2012/058738 filed on Mar. 30, 2012 and designated the U.S., the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The disclosures herein generally relate to a wireless communication apparatus. 
     BACKGROUND 
     A wireless apparatus built in a cellular phone or the like includes a wireless unit (also called a “radio frequency (RF) unit”) and a baseband processing apparatus. The interface between the wireless unit and the baseband processing apparatus is configured with lines including an analog signal line and a digital or analog control line. 
     In recent years, an RFIC (RF Integrated Circuit) included in a wireless unit can be made from a CMOS (Complementary Metal-Oxide Semiconductor) circuit. The RFIC can include an analog-digital converter (ADC) and a digital-analog converter (DAC). 
     Following this, an interface has been standardized for digital signal connection between an RFIC and a digital IC for baseband processing. The interface standardized for digital signal connection between an RFIC and a digital IC includes “DigRF”. 
     Version 3 of the DigRF standard (DigRF v3) is for an LVDS transmission frequency of about 300 MHz, and a DigRF packet does not include an error determination bit. Therefore, according to Version 3 of the DigRF standard, if an error occurs in a DigRF packet, retransmission control is not executed. 
     In contrast to DigRF v3, Version 4 of the DigRF standard (DigRF v4) is for an LVDS transmission frequency of about 1 GHz, and an error determination bit is provided in a DigRF packet. Therefore, in DigRF v4, error detection is executed for data between an RFIC and a baseband processing apparatus, and if an error is detected, retransmission control is executed for the data (see, for example, Patent Document 1). For example, when data is transmitted from an RFIC to a baseband processing apparatus, the baseband processing apparatus executes error detection in the data from the RFIC. If detecting an error in the data from the RFIC, the baseband processing apparatus makes a retransmission-request of the data to the RFIC. In response to receiving the retransmission-request of the data, the RFIC transmits the data again to the baseband processing apparatus. 
     RELATED-ART DOCUMENTS 
     Patent Documents 
     
         
         [Patent Document 1] Japanese Laid-open Patent Publication No. 2010-268395 
       
    
     Non-Patent Document 
     
         
         [Non-Patent Document 1] 3GPP TS25.211 V11.0.0, “5.3.2 Dedicated downlink physical channels”, 2011-12 
       
    
     When a retransmission process of data is executed in data transmission from a wireless unit to a baseband processing apparatus as described above, timing for the baseband processing apparatus to start a baseband process is delayed for time required for the retransmission process. Consequently, a process in the baseband processing apparatus cannot be completed within the time specified in the 3GPP (3rd Generation Partnership Project) specification, and, for example, there are cases where a delay occurs for timing of transmission power control. 
     The 3GPP specification specifies that a user terminal (also called “user equipment (UE)”) receives a wireless signal, for example, a dedicated physical channel (DPCH) from a base station (see, for example, Non-Patent Document 1). It is specified that such a user terminal demodulates a pilot symbol included in the DPCH, and calculates an SIR (Signal-to-Interference Ratio). It is also specified that such a user terminal maps information about power control based on reception power, into a dedicated physical control channel (DPCCH). 
     For a downlink DPCH, a delay offset of 296 chips at maximum is generated during a soft handover (SHO). Therefore, considering the maximum delay of the DPCH, the user terminal has to transmit an uplink DPCCH having the information about power control based on the received power mapped, at a timing of 216 chips after the reception of the pilot symbol. 
     However, when a retransmission process of data is executed at the DigRF interface between the wireless unit and the baseband processing apparatus in the wireless terminal, the baseband processing apparatus waits for the retransmission of a DigRF packet. Therefore, if the user terminal cannot transmit the uplink DPCCH having the information about power control based on the received power mapped, at a timing of 216 chips after the reception of the pilot symbol, the user terminal is forced to wait for a next transmission timing to transmit the uplink DPCCH having the information about power control based on the received power mapped. 
     Therefore, if a retransmission process is executed for data at a connection interface between elements in a wireless terminal, and if a required process is not completed within a process time specified in the 3GPP specification, transmission power control may be delayed in the downlink direction. 
     SUMMARY 
     According to at least an embodiment of the present invention, a wireless apparatus includes a wireless unit to convert a wireless signal received by an antenna into a baseband signal; and a baseband processing apparatus to receive a packet corresponding to the baseband signal via a communication line connected with the wireless unit, to detect an error in a transmission process of the packet via the communication line, to obtain the baseband signal based on packets other than the packet in which the error is detected, to generate transmission power information used for downlink transmission power control based on the obtained baseband signal, to transmit the baseband signal having the generated transmission power information reflected to the wireless unit via the communication line, and to have the wireless unit execute wireless transmission of a wireless signal corresponding to the baseband signal having the transmission power information reflected. 
     The object and advantages of the embodiment will be realized and attained by means of the elements and combinations particularly pointed out in the claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a wireless apparatus according to an embodiment of the present invention; 
         FIG. 2A  is a functional block diagram of a wireless apparatus according to an embodiment of the present invention; 
         FIG. 2B  is a functional block diagram of a wireless apparatus according to an embodiment of the present invention; 
         FIG. 3  illustrates an example of a DigRF packet; 
         FIG. 4  illustrates an example of a process for specifying a range of pilot symbols used for calculating a transmission TPC bit; 
         FIG. 5  illustrates an example of a process for calculating an SIR; 
         FIG. 6  illustrates an example of a process for calculating an SIR; 
         FIG. 7  is a timing chart of transmission power control according to an embodiment of the present invention; 
         FIG. 8  is a flowchart of a process for calculating an SIR according to an embodiment of the present invention; 
         FIG. 9A  is a flowchart of operations of a wireless apparatus according to an embodiment of the present invention; 
         FIG. 9B  is a flowchart of operations of a wireless apparatus according to an embodiment of the present invention; and 
         FIG. 10  is a timing chart of an example of transmission power control. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the following, embodiments of the present invention will be described with reference to the drawings. Note that elements having the same functions across the drawings are assigned the same numerical codes, and their description may not be repeated. 
     &lt;Wireless Apparatus  100 &gt; 
       FIG. 1  illustrates a wireless apparatus  100  according to an embodiment of the present invention.  FIG. 1  mainly illustrates an example of a hardware configuration. The wireless apparatus  100  is built in a user terminal, for example. 
     The user terminal may be any terminal appropriate for wireless communication, which includes a cellular phone, an information terminal, a personal digital assistant, a portable personal computer, and a smart phone, but it is not limited to these. The wireless apparatus  100  may also be built in an image forming apparatus or a household electric appliance. 
     In the present embodiment, the wireless apparatus  100  is described for a case where wireless access is executed in accordance with WCDMA (Wideband Code Division Multiple Access), but it may be executed in accordance with another method such as LTE (Long Term Evolution) or LTE-Advanced. 
     In the present embodiment, the wireless apparatus  100  is described for a case where the SIR is used as reception quality, but other indicators may be used. 
     The wireless apparatus  100  includes an RFIC  200  and a baseband processing apparatus  300 . The RFIC  200  and the baseband processing apparatus  300  may be implemented in semiconductor integrated circuits, respectively. The baseband processing apparatus  300  can be manufactured as a semiconductor integrated circuit by converting a program written in a circuit design language into circuit information by a compiler. 
     The RFIC  200  receives a wireless signal from another wireless apparatus, and inputs the wireless signal into the baseband processing apparatus  300 . Also, the RFIC  200  converts the signal from the baseband processing apparatus  300  into a wireless signal, and transmits the wireless signal to the other wireless apparatus. The other wireless apparatus includes a wireless base station. 
     The baseband processing apparatus  300  is connected with the RFIC  200 . For example, the baseband processing apparatus  300  and the RFIC  200  are connected with each other by an interface using digital signal based connection. The interface includes “DigRF”. The baseband processing apparatus  300  executes a baseband process for the digital signal from the RFIC  200 . Also, the baseband processing apparatus  300  inputs the digital signal to be transmitted, into the RFIC  200 . 
     The baseband processing apparatus  300  includes a DSP (Digital Signal Processor)  3002 , a CPU (Central Processing Unit)  3004 , a memory  3006 , and hardware  3008 . 
     The DSP  3002  executes baseband signal processing based on instructions from the CPU  3004 . The DSP  3002  generates data to be transmitted to the other wireless apparatus based on instructions from the CPU  3004 , and executes control for inputting the data into the RFIC  200 . 
     The CPU  3004  is connected with the DSP  3002 . The CPU  3004  has the DSP  3002  execute digital signal processing based on software such as built-in firmware and a program stored in the memory  3006 . 
     The memory  3006  is connected with the CPU  3004 . The memory  3006  stores the program executed by the DSP  3002  and the CPU  3004 . 
     The hardware  3008  is connected with the DSP  3002 . The hardware  3008  executes a modulation process, an encoding process, a demodulation process, and various calculations. 
       FIGS. 2A-2B  are functional block diagrams of the wireless apparatus  100  according to the present embodiment. 
     The wireless apparatus  100  includes the RFIC  200  and the baseband processing apparatus  300 .  FIG. 2A  mainly illustrates the RFIC  200  in the present embodiment.  FIG. 2B  mainly illustrates the baseband processing apparatus  300  in the present embodiment. 
     The RFIC  200  executes reception/transmission of a wireless signal with the other wireless apparatus via an antenna. 
     The baseband processing apparatus  300  is connected with the RFIC  200  via digital communication paths (RxPath and TxPath). The baseband processing apparatus  300  executes a baseband process for a DigRF-packeted signal from the RFIC  200 . Also, the baseband processing apparatus  300  inputs DigRF-packeted data into the RFIC  200 . 
     &lt;RFIC  200 &gt; 
     The RFIC  200  includes an RxADC  202 , a TxDAC  204 , and a DigRF control unit  206 . The DigRF control unit  206  includes a retransmission control unit  208 , a retransmission control unit  210 , an LVDS (Low Voltage Differential Signaling) driver  212 , and an LVDS receiver  214 . 
     The RxADC  202  receives a wireless signal from the other wireless apparatus via the antenna, and converts the wireless signal into a digital signal. The RxADC  202  inputs the digital signal into the retransmission control unit  208 . Note that other circuit elements (not illustrated) may be inserted between the antenna and the RxADC  202 , and between the RxADC  202  and the DigRF control unit  206 . 
     The retransmission control unit  208  is connected with the RxADC  202 . The retransmission control unit  208  executes buffering for the digital signal from the RxADC  202 . The retransmission control unit  208  inputs the digital signal from the RxADC  202  to the LVDS driver  212 . Also, if receiving a retransmission-request signal as input from the retransmission control unit  210 , the retransmission control unit  208  inputs a digital signal corresponding to the retransmission-request among the buffered digital signals, into the LVDS driver  212 . 
     The LVDS driver  212  is connected with the retransmission control unit  208 . The LVDS driver  212  generates a DigRF packet of the digital signal from the retransmission control unit  208 . The LVDS driver  212  executes a LVDS drive process for the DigRF-packeted signal (referred to as a “DigRF packet” below). Namely, the LVDS driver  212  outputs the DigRF packet to the baseband processing apparatus  300  via the RxPath. 
     The LVDS receiver  214  receives a transmission signal or a retransmission-request signal from the baseband processing apparatus  300 , and inputs it into the retransmission control unit  210 . 
     The retransmission control unit  210  is connected with the LVDS receiver  214  and the retransmission control unit  208 . The retransmission control unit  210  inputs a transmission signal from the LVDS receiver  214  into the TxDAC  204 . Also, the retransmission control unit  210  inputs a retransmission-request signal from the LVDS receiver  214  into the retransmission control unit  208 . 
     The TxDAC  204  is connected with the retransmission control unit  210 . The TxDAC  204  converts the transmission signal from the retransmission control unit  210  into an analog signal. The TxDAC  204  converts the transmission signal having been converted into the analog signal, into a wireless signal, and transmits the wireless signal to the other wireless apparatus via the antenna. Note that other circuit elements (not illustrated) may be inserted between the antenna and the TxDAC  204 , and between the TxDAC  204  and the DigRF control unit  206 . 
     &lt;Baseband Processor  300 &gt; 
     The baseband processing apparatus  300  includes a DigRF control unit  302 , a pilot symbol range specification unit  316 , a despreading unit  318 , a CPICH demodulation unit  320 , and an SIR calculation unit  322 . 
     The baseband processing apparatus  300  also includes a DPCH demodulation unit  324 , a data decoding unit  326 , a TFCI (Transport Format Combination Indicator) bit determination unit  328 , and a reception TPC bit determination unit  330 . 
     The baseband processing apparatus  300  also includes an SIR calculation unit  332 , a transmission TPC bit determination unit  334 , an encoding unit  336 , a modulation unit  338 , a transmission power calculation unit  340 , and a transmission unit  342 . 
     The DigRF control unit  302  includes an LVDS receiver  304 , a retransmission control unit  306 , an error symbol part determination unit  308 , a buffer  310 , an LVDS driver  312 , and a retransmission control unit  314 . 
     The error symbol part determination unit  308 , the pilot symbol range specification unit  316 , the TFCI bit determination unit  328 , and the reception TPC bit determination unit  330  are executed by the CPU  3004  based on the program stored in the memory  3006 . Alternatively, the error symbol part determination unit  308 , the pilot symbol range specification unit  316 , the TFCI bit determination unit  328 , and the reception TPC bit determination unit  330  may be executed by the CPU  3004  based on the firmware stored in an internal memory of the CPU  3004 . 
     The retransmission control unit  306  and  314 , the despreading unit  318 , and the transmission unit  342  are executed by the DSP  3002 . 
     The LVDS receiver  304 , the buffer  310 , the LVDS driver  312 , the CPICH demodulation unit  320 , the SIR calculation unit  322 , the DPCH demodulation unit  324 , and the data decoding unit  326  are executed by the hardware  3008 . Also, the SIR calculation unit  332 , the transmission TPC bit determination unit  334 , the encoding unit  336 , the modulation unit  338 , and the transmission power calculation unit  340  are executed by the hardware  3008 . 
     The LVDS receiver  304  is connected with the LVDS driver  212 . The LVDS receiver  304  receives a DigRF packet from the RFIC  200  via the RxPath. The LVDS receiver  304  inputs the DigRF packet from the RFIC  200  into the retransmission control unit  306 . 
     The retransmission control unit  306  is connected with the LVDS receiver  304 . The retransmission control unit  306  detects a data error in the DigRF packet from the LVDS receiver  304 . 
       FIG. 3  illustrates an example of a DigRF packet. 
     The DigRF packet includes a header, a payload, and an error detection code. 
     The header includes information representing a data type, information representing a frame number, and information representing a frame length. 
     The payload includes one or more symbols. In the example illustrated in  FIG. 3 , the payload includes  16  symbols. In the example illustrated in  FIG. 3 , the payload includes eight chips denoted as chip # 1  to chip # 8 . Namely, one chip includes two symbols. One chip includes two pieces of I data (I channel (ch)) and two pieces of Q data (Q channel (ch)). An I ch and a Q ch are represented with eight bits, respectively. One packet includes eight chips, and one chip includes two I channels and two Q channels. 
     The error detection code is used for determining whether an error is included in data included in the payload. The error detection code includes, for example, a cyclic redundancy check (CRC) code. 
     The retransmission control unit  306  makes a retransmission-request to the retransmission control unit  314  if an error is detected in data included in a DigRF packet. If an error is detected in data included in a DigRF packet, the retransmission control unit  306  inputs information representing the DigRF packet in which the error is detected (referred to as “error DigRF packet information” below) into the error symbol part determination unit  308 . Specifically, if an error is detected in data included in a DigRF packet, the retransmission control unit  306  inputs the information representing the frame number included in the header of the DigRF packet in which the error is detected, into the error symbol part determination unit  308 . 
     Also, the retransmission control unit  306  stores the DigRF packet in the buffer  310 , and inputs the DigRF packet into the SIR calculation unit  332 . 
     Also, if the DigRF packet from the LVDS receiver  304  is a retransmission packet, the retransmission control unit  306  replaces a DigRF packet stored in the buffer  310  with the retransmission DigRF packet. The retransmission control unit  306  executes control for inputting the DigRF packet stored in the buffer  310  into the despreading unit  318 . 
     The retransmission control unit  314  is connected with the retransmission control unit  306 . The retransmission control unit  314  inputs a transmission signal from the transmission unit  342  to the LVDS driver  312 . Also, in response to a retransmission-request from the retransmission control unit  306 , the retransmission control unit  314  inputs the retransmission-request signal into the LVDS driver  312 . 
     The LVDS driver  312  is connected with the retransmission control unit  314  and the LVDS receiver  214 . The LVDS driver  312  generates a DigRF packet of the retransmission-request signal from the retransmission control unit  314 . The LVDS driver  312  inputs the DigRF-packeted retransmission-request signal into the RFIC  200 . 
     Also, the LVDS driver  312  generates a DigRF packet of the transmission signal from the retransmission control unit  314 . The LVDS driver  312  inputs the DigRF-packeted transmission signal into the RFIC  200 . 
     The despreading unit  318  is connected with the buffer  310 . The despreading unit  318  applies despreading to the DigRF packet from the buffer  310 . The despreading unit  318  separates the DigRF packet having despreading applied into channels. Specifically, the despreading unit  318  separates the DigRF packet having despreading applied into a common pilot channel (CPICH) and a dedicated physical channel (DPCH). The despreading unit  318  inputs the CPICH into the CPICH demodulation unit  320 . Also, the despreading unit  318  inputs the DPCH into the DPCH demodulation unit  320 . Moreover, the despreading unit  318  inputs a transmission timing signal into the transmission unit  342 . 
     The CPICH demodulation unit  320  is connected with the despreading unit  318 . The CPICH demodulation unit  320  demodulates the CPICH from the despreading unit  318 . The CPICH demodulation unit  320  inputs the demodulated CPICH into the SIR calculation unit  322 . 
     The SIR calculation unit  322  is connected with the CPICH demodulation unit  320 . The SIR calculation unit  322  calculates an SIR based on the demodulated CPICH from the CPICH demodulation unit  320 . 
     The DPCH demodulation unit  324  is connected with the despreading unit  318 . The DPCH demodulation unit  324  demodulates the DPCH from the despreading unit  318 . The DPCH demodulation unit  324  inputs the demodulated DPCH into the data decoding unit  326 , the TFCI bit determination unit  328 , and the reception TPC bit determination unit  330 . 
     The data decoding unit  326  is connected with the DPCH demodulation unit  324 . The data decoding unit  326  decodes the demodulated DPCH from the DPCH demodulation unit  324 . 
     The TFCI bit determination unit  328  is connected with the DPCH demodulation unit  324 . The TFCI bit determination unit  328  determines a TFCI bit based on the demodulated DPCH from the DPCH demodulation unit  324 . 
     The reception TPC bit determination unit  330  is connected with the DPCH demodulation unit  324 . The reception TPC bit determination unit  330  determines whether the TPC bit included in the demodulated DPCH from the DPCH demodulation unit  324  indicates an up or a down. The reception TPC bit determination unit  330  inputs information representing whether the TPC bit included in the demodulated DPCH from the DPCH demodulation unit  324  indicates an up or a down (referred to as “reception TPC bit information” below), into the transmission power calculation unit  340 . 
     The transmission power calculation unit  340  is connected with the reception TPC bit determination unit  330 . The transmission power calculation unit  340  calculates transmission power of the DPCCH and DPDCH based on the reception TPC bit information from the reception TPC bit determination unit  330 . The transmission power calculation unit  340  inputs information representing the calculation result of the transmission power of the DPCCH and DPDCH, into the transmission unit  342 . 
     The error symbol part determination unit  308  is connected with the retransmission control unit  306 . The error symbol part determination unit  308  determines an error symbol location based on the error DigRF packet information from the retransmission control unit  306 . The error symbol part determination unit  308  inputs information representing the error symbol location (referred to as “error symbol information” below) into the pilot symbol range specification unit  316 . 
     The pilot symbol range specification unit  316  is connected with the error symbol part determination unit  308 . The pilot symbol range specification unit  31  specifies a range of pilot symbols used for calculating a TPC bit to be transmitted to the other wireless apparatus based on the error symbol information from the error symbol part determination unit  308 . 
     The pilot symbol range specification unit  316  inputs information representing the range of pilot symbols used for calculating a TPC bit to be transmitted to the other wireless apparatus (referred to as “pilot symbol range information” below) into the SIR calculation unit  332 . 
       FIG. 4  illustrates a process executed by the pilot symbol range specification unit  316 .  FIG. 4  illustrates a table including multiple DigRF packets where each record stores whether an error is detected in each of the packets. The table is used for obtaining a range of pilot symbols used for calculating a TPC bit to be transmitted to the other wireless apparatus (referred to as a “transmission TPC bit” below). 
     The pilot symbol range specification unit  316  in the present embodiment provides the table where the address of a DigRF packet is associated with the error symbol information and the pilot symbol range information. 
     The pilot symbol range specification unit  316  specifies the pilot symbol range with multiple DigRF packets as a unit. The pilot symbol range specification unit  316  specifies pilot symbols included in DigRF packets other than the DigRF packet that includes the error symbol specified by the error symbol information, as the pilot symbol range information. 
     The pilot symbol range specification unit  316  in the embodiment specifies the pilot symbol range by the unit of 32 DigRF packets. The pilot symbol range specification unit  316  identifies the DigRF packet that includes an error symbol based on the error symbol information from the error symbol part determination unit  308 . In the example illustrated in  FIG. 4 , the pilot symbol range specification unit  316  identifies a DigRF packet whose DigRF packet address is “18”. The pilot symbol range specification unit  316  identifies DigRF packets other than the packet whose DigRF packet address is “18”. The pilot symbol range specification unit  316  specifies DigRF packets other than the packet whose DigRF packet address is “18”, as the pilot symbol range information. Specifically, the pilot symbol range specification unit  316  specifies the DigRF packets whose DigRF packet addresses are 0-17 and 19-31, as the pilot symbol range information. 
     After having specified the pilot symbol range information, the pilot symbol range specification unit  316  executes the same process for the next 32 DigRF packets. 
     The SIR calculation unit  332  is connected with the pilot symbol range specification unit  316  and the retransmission control unit  306 . The SIR calculation unit  332  calculates an SIR based on the DigRF packet from the retransmission control unit  306  and the pilot symbol range information from the pilot symbol range specification unit  316 . Specifically, the SIR calculation unit  332  calculates likelihood for eight chips included in the DigRF packet by taking a quarter chip as one sample. The SIR calculation unit  332  calculates the likelihood for pilot symbols specified by the pilot symbol range information. The SIR calculation unit  332  sums the calculation results of the likelihood, and outputs the average value as the SIR. 
     &lt;Case where an Error is Not Detected in DigRF Packet&gt; 
       FIG. 5  illustrates an SIR calculation process when an error is not detected in a DigRF packet. If an error is not detected in the DigRF packet, the retransmission control unit  306  does not input error DigRF packet information into the error symbol part determination unit  308 . Alternatively, if an error is not detected in the DigRF packet, the retransmission control unit  306  may input information representing that an error is not detected, into the error symbol part determination unit  308 . 
     Moreover, the error symbol part determination unit  308  does not input error symbol information into the pilot symbol range specification unit  316 . Alternatively, the error symbol part determination unit  308  may input information representing that an error is not detected, into the pilot symbol range specification unit  316 . Therefore, the pilot symbol range specification unit  316  does not input pilot symbol range information into the SIR calculation unit  332 . Alternatively, the pilot symbol range specification unit  316  may input information specifying the entire range as the pilot symbol range information, into the SIR calculation unit  332 . In this case, the SIR calculation unit  332  calculates the SIR based on the DigRF packet from the retransmission control unit  306 . Specifically, the SIR calculation unit  332  calculates likelihood for 256 chips included in the DigRF packet by taking a quarter chip as one sample. The SIR calculation unit  332  sums the calculation results of the likelihood, and takes the average to calculate the SIR used for calculating a transmission TPC bit. 
     &lt;Case where an Error is Detected in DigRF Packet&gt; 
       FIG. 6  illustrates an SIR calculation process when an error is detected in a DigRF packet. If an error is detected in the DigRF packet, the retransmission control unit  306  inputs the error DigRF packet information into the error symbol part determination unit  308 . 
     The error symbol part determination unit  308  determines an error symbol location based on the error DigRF packet information from the retransmission control unit  306 . The error symbol part determination unit  308  inputs the error symbol information into the pilot symbol range specification unit  316 . 
     The pilot symbol range specification unit  31  specifies a range of pilot symbols used for calculating a transmission TPC bit based on the error symbol information from the error symbol part determination unit  308 . Specifically, as illustrated in  FIG. 6 , the pilot symbol range specification unit  316  identifies a DigRF packet that includes a symbol designated by the error symbol location specified in the error symbol information. The pilot symbol range specification unit  316  sets the range of the pilot symbols included in DigRF packets other than the identified DigRF packet, as the range of the pilot symbols used for calculating a transmission TPC bit. The pilot symbol range specification unit  316  inputs the pilot symbol range information into the SIR calculation unit  332 . 
     The SIR calculation unit  332  calculates an SIR based on the DigRF packet from the retransmission control unit  306  and the pilot symbol range information from the pilot symbol range specification unit  316 . Specifically, the SIR calculation unit  332  calculates likelihood for eight chips included in the DigRF packet by taking a quarter chip as one sample. The SIR calculation unit  332  calculates the likelihood for the pilot symbols specified by the pilot symbol range information. For example, if an error is detected in the DigRF packet, the SIR calculation unit  332  calculates the likelihood for 248 chips, which is obtained by subtracting eight chips from 256 chips included in 32 DigRF packets, by taking a quarter chip as one sample. The SIR calculation unit  332  sums the calculation results of the likelihood, and outputs the average value as the SIR. If there are a small number of DigRF packets in which errors are detected, it is assumed the influence on the SIR is tolerable even if the likelihood is calculated based on DigRF packets other than the DigRF packet. 
     The transmission TPC bit determination unit  334  is connected with the SIR calculation unit  332 . The transmission TPC bit determination unit  334  calculates a transmission TPC bit based on the SIR from the SIR calculation unit  332 . For example, the transmission TPC bit determination unit  334  may calculate a transmission TPC bit so that the SIR from the SIR calculation unit  332  becomes a predetermined SIR. The transmission TPC bit determination unit  334  inputs the transmission TPC bit into the encoding unit  336 . 
     The encoding unit  336  is connected with the transmission TPC bit determination unit  334 . The encoding unit  336  encodes the transmission TPC bit from the transmission TPC bit determination unit  334 . The encoding unit  336  inputs the encoded transmission TPC bit (referred to as the “encoded transmission TPC bit” below) into the modulation unit  338 . 
     The modulation unit  338  is connected with the encoding unit  336 . The modulation unit  338  modulates the encoded transmission TPC bit from the encoding unit  336 . The modulation unit  338  inputs the modulated encoded transmission TPC bit into the transmission unit  342 . 
     The transmission unit  342  is connected with the modulation unit  338  and the transmission power calculation unit  340 . The transmission unit  342  executes a process for transmitting the modulated encoded transmission TPC bit from the modulation unit  338  based on information about a calculation result of transmission power from the transmission power calculation unit  340 . When executing the process for transmitting the encoded transmission TPC bit, the transmission unit  342  controls transmission timing following a transmission timing signal from the despreading unit  318 . 
     &lt;Transmission Power Control Process&gt; 
       FIG. 7  is a timing chart of a transmission power control process in the wireless apparatus  100  according to the present embodiment. In  FIG. 7 , a state is illustrated as an example where a delay offset of a maximum of 296 chips is generated by a soft handover (SHO). 
     The 3GPP specifies that an SIR is calculated after receiving a downlink DPCH, by demodulating a pilot symbol that is mapped in the tenth symbol of the DPCH. 
     The 3GPP also specifies that a transmission TPC bit is mapped in a TPC included in an uplink DPCCH that comes at timing of 512 chips after the reception of the pilot symbol. 
     The downlink DPCH generates the delay offset of the maximum of 296 chips during the soft handover. Considering the delay offset of the DPCH, the uplink DPCCH having the transmission TPC bit mapped needs to be transmitted at a timing of 216 chips (512 chips−296 chips) after the reception of the pilot symbol. 
     The RFIC  200  receives the downlink DPCH  700 , and generates a DigRF packet. The RFIC  200  transmits the DigRF packet to the baseband processing apparatus  300  ( 702 ). Note that if an error is detected in the DigRF packet, the baseband processing apparatus  300  executes a retransmission control process of the data. However, the baseband processing apparatus  300  calculates a transmission TPC bit without waiting for the arrival of the retransmission data by the retransmission control. 
     The baseband processing apparatus  300  determines the error symbol location of the DigRF packet ( 704 ). Next, the baseband processing apparatus  300  calculates the transmission TPC bit based on chips included in DigRF packets other than the DigRF packet including the error symbol, and executes the process for transmitting the transmission TPC bit ( 706 ). Specifically, the baseband processing apparatus  300  maps the transmission TPC bit into the uplink DPCCH. 
     The baseband processing apparatus  300  transmits the uplink DPCCH having the transmission TPC bit mapped to the RFIC  200  ( 708 ). 
     The RFIC  200  transmits the uplink DPCCH from the baseband processing apparatus  300 . 
     By calculating the transmission TPC bit without waiting for the arrival of the retransmission data by the retransmission control, the wireless apparatus  100  can transmit the uplink DPCCH having the transmission TPC bit mapped, at a timing of 216 chips after the reception of the pilot. Therefore, even if an error is detected in the packet from the RFIC  200 , the baseband processing apparatus  300  in the wireless apparatus  100  can transmit the uplink DPCCH having the transmission TPC bit mapped, at the timing of 216 chips after the reception of the pilot. Therefore, a delay time can be shortened for transmission power control for the wireless apparatus  100  by the other wireless apparatus, especially by a base station. 
     &lt;SIR Calculation Process&gt; 
       FIG. 8  is a flowchart of a process for calculating an SIR according to the present embodiment.  FIG. 8  mainly illustrates a process executed by the error symbol part determination unit  308 , the pilot symbol range specification unit  316 , and the SIR calculation unit  332 . 
     At Step S 804 , the SIR calculation unit  332  receives a DigRF packet from the retransmission control unit  306 . 
     At Step S 806 , the SIR calculation unit  332  counts the number of DigRF packets from the retransmission control unit  306 . 
     At Step S 808 , the error symbol part determination unit  308  determines whether an error is detected in the DigRF packet based on error DigRF packet information from the retransmission control unit  306 . 
     At Step S 810 , if it is determined at Step S 808  that an error is detected in the DigRF packet, the pilot symbol range specification unit  316  counts the number of DigRF packets in which errors are detected. Specifically, the pilot symbol range specification unit  316  sets “1” to a part corresponding to the DigRF packet in which an error is detected in the table illustrated in  FIG. 4  for counting the number of DigRF packets in which errors are detected. 
     At Step S 812 , if it is determined at Step S 808  that an error is not detected in the DigRF packet, the following steps are executed. Namely, the pilot symbol range specification unit  316  sets “0” to the part corresponding to the DigRF packet in which an error is not detected in the table illustrated in  FIG. 4 . After that, the pilot symbol range specification unit  316  determines whether the number of DigRF packets reach 32. The pilot symbol range specification unit  316  may determine whether the number of chips reach 256. 
     The following is also executed in Step S 812  after setting “1” to the part corresponding to the DigRF packet in which the error is detected. Namely, the pilot symbol range specification unit  316  determines whether the number of DigRF packets reach 32. The pilot symbol range specification unit  316  may determine whether the number of chips reach 256. 
     At Step S 814 , if it is determined at Step S 812  that the number of DigRF packets reach 32, the SIR calculation unit  332  calculates an SIR. The SIR calculation unit  332  calculates likelihood based on the pilot symbols in the range specified by the pilot symbol range information, by taking a quarter chip as one sample. The SIR calculation unit  332  sums the calculation results of the likelihood. Namely, the SIR calculation unit  332  sums the likelihood calculated for chips included in DigRF packets other than the DigRF packet that includes the symbol in which an error is detected. 
     If it is determined at Step S 812  that the number of DigRF packets does not reach 32, the process goes back to Step S 804 . 
     At Step S 816 , the SIR calculation unit  332  executes an averaging process of the SIR. Namely, the SIR calculation unit  332  obtains the number of samples by excluding DigRF packets in which errors are detected, from the 32 DigRF packets. The SIR calculation unit  332  executes the averaging process of the SIR by dividing the total value of the likelihood by the number of samples. 
     &lt;Operations of Wireless Apparatus  100 &gt; 
       FIGS. 9A-9B  illustrate operations of the wireless apparatus  100  according to the present embodiment. 
     The wireless apparatus  100  operates in accordance with DigRF v4. 
     At Step S 902 , the RFIC  200  receives a wireless signal from the other wireless apparatus. Namely, the retransmission control unit  208  receives IQ data as input from the RxADC  202 . 
     At Step S 904 , the retransmission control unit  208  executes buffering of the IQ data, and inputs the IQ data to the LVDS driver  212 . 
     At Step S 906 , the LVDS driver  212  generates a DigRF packet of the IQ data from the retransmission control unit  208 . The LVDS driver  212  outputs the DigRF packet to the LVDS receiver  304 . 
     At Step S 908 , the LVDS receiver  304  receives the DigRF packet from the RFIC  200 . The LVDS receiver  304  inputs the DigRF packet from the RFIC  200  into the retransmission control unit  306 . 
     At Step S 910 , the retransmission control unit  306  determines whether a data error is detected in the DigRF packet from the LVDS receiver  304 . 
     At Step S 912 , if a data error is detected in the DigRF packet from the LVDS receiver  304  at Step S 910 , the error symbol part determination unit  308  determines the symbol in which the error is detected. The error symbol part determination unit  308  inputs the error symbol information into the pilot symbol range specification unit  316 . 
     At Step S 914 , the pilot symbol range specification unit  316  specifies the range of pilot symbols used for calculating the transmission TPC bit based on the error symbol information from the error symbol part determination unit  308 . The pilot symbol range specification unit  316  inputs the pilot symbol range information into the SIR calculation unit  332 . 
     At Step S 916 , the SIR calculation unit  332  executes an SIR calculation process. 
     At Step S 918 , the transmission TPC bit determination unit  334  calculates the transmission TPC bit based on the SIR calculated by the SIR calculation unit  332 . 
     At Step S 920 , the modulation unit  338  executes a modulation process of the IQ data to be transmitted. 
     At Step S 922 , the transmission unit  342  transmits the transmission TPC bit calculated by the transmission TPC bit determination unit  334  and the IQ data modulated at Step S 920 . 
     At Step S 924 , the retransmission control unit  314  makes a retransmission-request of the DigRF packet. 
     At Step S 926 , the LVDS driver  312  generates a DigRF packet of the retransmission-request signal from the retransmission control unit  314 . The LVDS driver  312  transmits the DigRF-packeted retransmission-request signal to the RFIC  200 . 
     At Step S 928 , the LVDS receiver  214  receives the DigRF-packeted retransmission-request signal from the LVDS driver  312 . The LVDS receiver  214  inputs the retransmission-request signal into the retransmission control unit  210 . 
     At Step S 930 , the retransmission control unit  210  makes a retransmission-request to the retransmission control unit  208  based on the retransmission-request signal from the LVDS receiver  214 . In response to the retransmission-request from the retransmission control unit  210 , the retransmission control unit  208  inputs the IQ data to be retransmitted into the LVDS driver  212 . 
     At Step S 932 , the LVDS driver  212  generates a DigRF packet of the IQ data from the retransmission control unit  208  for retransmission. The LVDS driver  212  outputs the DigRF packet to the LVDS receiver  304 . 
     At Step S 934 , the LVDS receiver  304  receives the DigRF packet from the RFIC  200 . The LVDS receiver  304  inputs the DigRF packet from the RFIC  200  into the buffer  310  via the retransmission control unit  306 . 
     At Step S 936 , the buffer  310  replaces IQ data among the stored IQ data that corresponds to the IQ data retransmitted from the retransmission control unit  306 . Namely, the buffer  310  updates the IQ data among the stored IQ data that corresponds to the IQ data retransmitted from the retransmission control unit  306 . The buffer  310  inputs the stored IQ data into the despreading unit  318 . 
     At Step S 938 , the despreading unit  318  executes a despreading process for the IQ data from the buffer  310 . 
     At Step S 940 , the CPICH demodulation unit  320  demodulates the CPICH. Also, at Step S 940 , the DPCH demodulation unit  320  demodulates the DPCH. 
     At Step S 942 , the LVDS driver  312  generates a DigRF packet of the IQ data transmitted from the transmission unit  342 . The LVDS driver  312  transmits the DigRF-packeted IQ data to the LVDS receiver  214 . 
     At Step S 944 , the LVDS receiver  214  receives the DigRF packet from the baseband processing apparatus  300 . The LVDS receiver  214  converts the DigRF packet from the baseband processing apparatus  300  into IQ data. The LVDS receiver  214  inputs the IQ data into the TxDAC  204  via the retransmission control unit  210 . 
     At Step S 946 , the TxDAC  204  transmits the IQ data from the LVDS receiver  214 . 
     By the operations of the wireless apparatus  100  in the present embodiment illustrated in  FIGS. 9A-9B , the transmission TPC bit is calculated without waiting for the arrival of the retransmission data by the retransmission control. Therefore, the wireless apparatus  100  can shorten time for transmitting the uplink DPCCH having the transmission TPC bit mapped after the reception of a pilot. 
       FIG. 10  illustrates an example where an SIR is calculated after waiting for retransmission of a DigRF packet if an error is detected in the DigRF packet from the RFIC. 
     In  FIG. 10 , similarly to  FIG. 7 , a state is illustrated as an example where a delay offset of a maximum of 296 chips is generated by a soft handover. 
     The RFIC receives a downlink DPCH  1000 , and generates a DigRF packet. The RFIC transmits the DigRF packet to the baseband processing apparatus ( 1002 ). Note that if an error is detected in the DigRF packet, the baseband processing apparatus makes a retransmission-request of the data. In response to the retransmission-request from the baseband processing apparatus, the DigRF packet corresponding to the retransmission-request is retransmitted from the RFIC. Namely, the retransmission control is executed for the DigRF packet. Therefore, the box  1002  includes transfer time and retransmission time. 
     The baseband processing apparatus transmits the transmission TPC bit ( 1004 ). Specifically, the baseband processing apparatus calculates an SIR based on DigRF packets including the retransmitted DigRF packet, and calculates the transmission TPC bit. The baseband processing apparatus generates an uplink DPCCH including the transmission TPC bit. There are cases where time of 216 chips passes after the reception of the pilot at this moment. Although the 3GPP specifies that the transmission TPC bit is mapped into a TPC included in an uplink DPCCH at timing of 512 chips after the reception of the pilot symbol, it is too late. 
     The baseband processing apparatus generates a DigRF packet of the uplink DPCCH including the transmission TPC bit, and transfers it to the RFIC. The RFIC transmits the uplink DPCCH including the transmission TPC bit ( 1010 ). In this case, the transmission TPC bit is mapped into a next slot. 
     In the transmission power control process illustrated in  FIG. 7 , the retransmitted DigRF packet is not used for calculating the transmission TPC bit. Therefore, time can be shortened for retransmission of the DigRF packet for the process of calculating the transmission TPC bit after the reception of the pilot. 
     According to the present embodiment, if an error is detected in a DigRF packet from the RFIC  200 , the uplink DPCCH having the transmission TPC bit mapped can be transmitted at a timing of 216 chips after the reception of the pilot. Namely, time can be shortened for transmission of the uplink DPCCH having the transmission TPC bit mapped after the reception of the pilot. 
     According to the present embodiment, in the wireless apparatus in accordance with DigRF v4, if an error is detected in a DigRF packet from the RFIC, the baseband processing apparatus calculates an SIR based on DigRF packets other than the DigRF packet. 
     The baseband processing apparatus calculates the transmission TPC bit based on the SIR calculated based on DigRF packets other than the DigRF packet in which an error is detected. In this way, a process for calculating the transmission TPC bit is not influenced even if a retransmission process of a DigRF packet is executed. Namely, it is possible to shorten delay of transmission power control caused by delay of transmission of the transmission TPC bit. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.