Wireless apparatus, baseband processing apparatus, and communication method

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.

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.

Patent Documents

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.

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.

FIG. 1illustrates a wireless apparatus100according to an embodiment of the present invention.FIG. 1mainly illustrates an example of a hardware configuration. The wireless apparatus100is 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 apparatus100may also be built in an image forming apparatus or a household electric appliance.

In the present embodiment, the wireless apparatus100is 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 apparatus100is described for a case where the SIR is used as reception quality, but other indicators may be used.

The wireless apparatus100includes an RFIC200and a baseband processing apparatus300. The RFIC200and the baseband processing apparatus300may be implemented in semiconductor integrated circuits, respectively. The baseband processing apparatus300can be manufactured as a semiconductor integrated circuit by converting a program written in a circuit design language into circuit information by a compiler.

The RFIC200receives a wireless signal from another wireless apparatus, and inputs the wireless signal into the baseband processing apparatus300. Also, the RFIC200converts the signal from the baseband processing apparatus300into 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 apparatus300is connected with the RFIC200. For example, the baseband processing apparatus300and the RFIC200are connected with each other by an interface using digital signal based connection. The interface includes “DigRF”. The baseband processing apparatus300executes a baseband process for the digital signal from the RFIC200. Also, the baseband processing apparatus300inputs the digital signal to be transmitted, into the RFIC200.

The baseband processing apparatus300includes a DSP (Digital Signal Processor)3002, a CPU (Central Processing Unit)3004, a memory3006, and hardware3008.

The DSP3002executes baseband signal processing based on instructions from the CPU3004. The DSP3002generates data to be transmitted to the other wireless apparatus based on instructions from the CPU3004, and executes control for inputting the data into the RFIC200.

The CPU3004is connected with the DSP3002. The CPU3004has the DSP3002execute digital signal processing based on software such as built-in firmware and a program stored in the memory3006.

The memory3006is connected with the CPU3004. The memory3006stores the program executed by the DSP3002and the CPU3004.

The hardware3008is connected with the DSP3002. The hardware3008executes a modulation process, an encoding process, a demodulation process, and various calculations.

FIGS. 2A-2Bare functional block diagrams of the wireless apparatus100according to the present embodiment.

The wireless apparatus100includes the RFIC200and the baseband processing apparatus300.FIG. 2Amainly illustrates the RFIC200in the present embodiment.FIG. 2Bmainly illustrates the baseband processing apparatus300in the present embodiment.

The RFIC200executes reception/transmission of a wireless signal with the other wireless apparatus via an antenna.

The baseband processing apparatus300is connected with the RFIC200via digital communication paths (RxPath and TxPath). The baseband processing apparatus300executes a baseband process for a DigRF-packeted signal from the RFIC200. Also, the baseband processing apparatus300inputs DigRF-packeted data into the RFIC200.

The RFIC200includes an RxADC202, a TxDAC204, and a DigRF control unit206. The DigRF control unit206includes a retransmission control unit208, a retransmission control unit210, an LVDS (Low Voltage Differential Signaling) driver212, and an LVDS receiver214.

The RxADC202receives a wireless signal from the other wireless apparatus via the antenna, and converts the wireless signal into a digital signal. The RxADC202inputs the digital signal into the retransmission control unit208. Note that other circuit elements (not illustrated) may be inserted between the antenna and the RxADC202, and between the RxADC202and the DigRF control unit206.

The retransmission control unit208is connected with the RxADC202. The retransmission control unit208executes buffering for the digital signal from the RxADC202. The retransmission control unit208inputs the digital signal from the RxADC202to the LVDS driver212. Also, if receiving a retransmission-request signal as input from the retransmission control unit210, the retransmission control unit208inputs a digital signal corresponding to the retransmission-request among the buffered digital signals, into the LVDS driver212.

The LVDS driver212is connected with the retransmission control unit208. The LVDS driver212generates a DigRF packet of the digital signal from the retransmission control unit208. The LVDS driver212executes a LVDS drive process for the DigRF-packeted signal (referred to as a “DigRF packet” below). Namely, the LVDS driver212outputs the DigRF packet to the baseband processing apparatus300via the RxPath.

The LVDS receiver214receives a transmission signal or a retransmission-request signal from the baseband processing apparatus300, and inputs it into the retransmission control unit210.

The retransmission control unit210is connected with the LVDS receiver214and the retransmission control unit208. The retransmission control unit210inputs a transmission signal from the LVDS receiver214into the TxDAC204. Also, the retransmission control unit210inputs a retransmission-request signal from the LVDS receiver214into the retransmission control unit208.

The TxDAC204is connected with the retransmission control unit210. The TxDAC204converts the transmission signal from the retransmission control unit210into an analog signal. The TxDAC204converts 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 TxDAC204, and between the TxDAC204and the DigRF control unit206.

The baseband processing apparatus300includes a DigRF control unit302, a pilot symbol range specification unit316, a despreading unit318, a CPICH demodulation unit320, and an SIR calculation unit322.

The baseband processing apparatus300also includes a DPCH demodulation unit324, a data decoding unit326, a TFCI (Transport Format Combination Indicator) bit determination unit328, and a reception TPC bit determination unit330.

The baseband processing apparatus300also includes an SIR calculation unit332, a transmission TPC bit determination unit334, an encoding unit336, a modulation unit338, a transmission power calculation unit340, and a transmission unit342.

The DigRF control unit302includes an LVDS receiver304, a retransmission control unit306, an error symbol part determination unit308, a buffer310, an LVDS driver312, and a retransmission control unit314.

The error symbol part determination unit308, the pilot symbol range specification unit316, the TFCI bit determination unit328, and the reception TPC bit determination unit330are executed by the CPU3004based on the program stored in the memory3006. Alternatively, the error symbol part determination unit308, the pilot symbol range specification unit316, the TFCI bit determination unit328, and the reception TPC bit determination unit330may be executed by the CPU3004based on the firmware stored in an internal memory of the CPU3004.

The retransmission control unit306and314, the despreading unit318, and the transmission unit342are executed by the DSP3002.

The LVDS receiver304, the buffer310, the LVDS driver312, the CPICH demodulation unit320, the SIR calculation unit322, the DPCH demodulation unit324, and the data decoding unit326are executed by the hardware3008. Also, the SIR calculation unit332, the transmission TPC bit determination unit334, the encoding unit336, the modulation unit338, and the transmission power calculation unit340are executed by the hardware3008.

The LVDS receiver304is connected with the LVDS driver212. The LVDS receiver304receives a DigRF packet from the RFIC200via the RxPath. The LVDS receiver304inputs the DigRF packet from the RFIC200into the retransmission control unit306.

The retransmission control unit306is connected with the LVDS receiver304. The retransmission control unit306detects a data error in the DigRF packet from the LVDS receiver304.

FIG. 3illustrates 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 inFIG. 3, the payload includes16symbols. In the example illustrated inFIG. 3, the payload includes eight chips denoted as chip #1to 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 unit306makes a retransmission-request to the retransmission control unit314if 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 unit306inputs 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 unit308. Specifically, if an error is detected in data included in a DigRF packet, the retransmission control unit306inputs 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 unit308.

Also, the retransmission control unit306stores the DigRF packet in the buffer310, and inputs the DigRF packet into the SIR calculation unit332.

Also, if the DigRF packet from the LVDS receiver304is a retransmission packet, the retransmission control unit306replaces a DigRF packet stored in the buffer310with the retransmission DigRF packet. The retransmission control unit306executes control for inputting the DigRF packet stored in the buffer310into the despreading unit318.

The retransmission control unit314is connected with the retransmission control unit306. The retransmission control unit314inputs a transmission signal from the transmission unit342to the LVDS driver312. Also, in response to a retransmission-request from the retransmission control unit306, the retransmission control unit314inputs the retransmission-request signal into the LVDS driver312.

The LVDS driver312is connected with the retransmission control unit314and the LVDS receiver214. The LVDS driver312generates a DigRF packet of the retransmission-request signal from the retransmission control unit314. The LVDS driver312inputs the DigRF-packeted retransmission-request signal into the RFIC200.

Also, the LVDS driver312generates a DigRF packet of the transmission signal from the retransmission control unit314. The LVDS driver312inputs the DigRF-packeted transmission signal into the RFIC200.

The despreading unit318is connected with the buffer310. The despreading unit318applies despreading to the DigRF packet from the buffer310. The despreading unit318separates the DigRF packet having despreading applied into channels. Specifically, the despreading unit318separates the DigRF packet having despreading applied into a common pilot channel (CPICH) and a dedicated physical channel (DPCH). The despreading unit318inputs the CPICH into the CPICH demodulation unit320. Also, the despreading unit318inputs the DPCH into the DPCH demodulation unit320. Moreover, the despreading unit318inputs a transmission timing signal into the transmission unit342.

The CPICH demodulation unit320is connected with the despreading unit318. The CPICH demodulation unit320demodulates the CPICH from the despreading unit318. The CPICH demodulation unit320inputs the demodulated CPICH into the SIR calculation unit322.

The SIR calculation unit322is connected with the CPICH demodulation unit320. The SIR calculation unit322calculates an SIR based on the demodulated CPICH from the CPICH demodulation unit320.

The DPCH demodulation unit324is connected with the despreading unit318. The DPCH demodulation unit324demodulates the DPCH from the despreading unit318. The DPCH demodulation unit324inputs the demodulated DPCH into the data decoding unit326, the TFCI bit determination unit328, and the reception TPC bit determination unit330.

The data decoding unit326is connected with the DPCH demodulation unit324. The data decoding unit326decodes the demodulated DPCH from the DPCH demodulation unit324.

The TFCI bit determination unit328is connected with the DPCH demodulation unit324. The TFCI bit determination unit328determines a TFCI bit based on the demodulated DPCH from the DPCH demodulation unit324.

The reception TPC bit determination unit330is connected with the DPCH demodulation unit324. The reception TPC bit determination unit330determines whether the TPC bit included in the demodulated DPCH from the DPCH demodulation unit324indicates an up or a down. The reception TPC bit determination unit330inputs information representing whether the TPC bit included in the demodulated DPCH from the DPCH demodulation unit324indicates an up or a down (referred to as “reception TPC bit information” below), into the transmission power calculation unit340.

The transmission power calculation unit340is connected with the reception TPC bit determination unit330. The transmission power calculation unit340calculates transmission power of the DPCCH and DPDCH based on the reception TPC bit information from the reception TPC bit determination unit330. The transmission power calculation unit340inputs information representing the calculation result of the transmission power of the DPCCH and DPDCH, into the transmission unit342.

The error symbol part determination unit308is connected with the retransmission control unit306. The error symbol part determination unit308determines an error symbol location based on the error DigRF packet information from the retransmission control unit306. The error symbol part determination unit308inputs information representing the error symbol location (referred to as “error symbol information” below) into the pilot symbol range specification unit316.

The pilot symbol range specification unit316is connected with the error symbol part determination unit308. The pilot symbol range specification unit31specifies 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 unit308.

The pilot symbol range specification unit316inputs 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 unit332.

FIG. 4illustrates a process executed by the pilot symbol range specification unit316.FIG. 4illustrates 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 unit316in 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 unit316specifies the pilot symbol range with multiple DigRF packets as a unit. The pilot symbol range specification unit316specifies 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 unit316in the embodiment specifies the pilot symbol range by the unit of 32 DigRF packets. The pilot symbol range specification unit316identifies the DigRF packet that includes an error symbol based on the error symbol information from the error symbol part determination unit308. In the example illustrated inFIG. 4, the pilot symbol range specification unit316identifies a DigRF packet whose DigRF packet address is “18”. The pilot symbol range specification unit316identifies DigRF packets other than the packet whose DigRF packet address is “18”. The pilot symbol range specification unit316specifies DigRF packets other than the packet whose DigRF packet address is “18”, as the pilot symbol range information. Specifically, the pilot symbol range specification unit316specifies 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 unit316executes the same process for the next 32 DigRF packets.

The SIR calculation unit332is connected with the pilot symbol range specification unit316and the retransmission control unit306. The SIR calculation unit332calculates an SIR based on the DigRF packet from the retransmission control unit306and the pilot symbol range information from the pilot symbol range specification unit316. Specifically, the SIR calculation unit332calculates likelihood for eight chips included in the DigRF packet by taking a quarter chip as one sample. The SIR calculation unit332calculates the likelihood for pilot symbols specified by the pilot symbol range information. The SIR calculation unit332sums the calculation results of the likelihood, and outputs the average value as the SIR.

<Case where an Error is Not Detected in DigRF Packet>

FIG. 5illustrates 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 unit306does not input error DigRF packet information into the error symbol part determination unit308. Alternatively, if an error is not detected in the DigRF packet, the retransmission control unit306may input information representing that an error is not detected, into the error symbol part determination unit308.

Moreover, the error symbol part determination unit308does not input error symbol information into the pilot symbol range specification unit316. Alternatively, the error symbol part determination unit308may input information representing that an error is not detected, into the pilot symbol range specification unit316. Therefore, the pilot symbol range specification unit316does not input pilot symbol range information into the SIR calculation unit332. Alternatively, the pilot symbol range specification unit316may input information specifying the entire range as the pilot symbol range information, into the SIR calculation unit332. In this case, the SIR calculation unit332calculates the SIR based on the DigRF packet from the retransmission control unit306. Specifically, the SIR calculation unit332calculates likelihood for 256 chips included in the DigRF packet by taking a quarter chip as one sample. The SIR calculation unit332sums the calculation results of the likelihood, and takes the average to calculate the SIR used for calculating a transmission TPC bit.

<Case where an Error is Detected in DigRF Packet>

FIG. 6illustrates 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 unit306inputs the error DigRF packet information into the error symbol part determination unit308.

The error symbol part determination unit308determines an error symbol location based on the error DigRF packet information from the retransmission control unit306. The error symbol part determination unit308inputs the error symbol information into the pilot symbol range specification unit316.

The pilot symbol range specification unit31specifies a range of pilot symbols used for calculating a transmission TPC bit based on the error symbol information from the error symbol part determination unit308. Specifically, as illustrated inFIG. 6, the pilot symbol range specification unit316identifies a DigRF packet that includes a symbol designated by the error symbol location specified in the error symbol information. The pilot symbol range specification unit316sets 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 unit316inputs the pilot symbol range information into the SIR calculation unit332.

The SIR calculation unit332calculates an SIR based on the DigRF packet from the retransmission control unit306and the pilot symbol range information from the pilot symbol range specification unit316. Specifically, the SIR calculation unit332calculates likelihood for eight chips included in the DigRF packet by taking a quarter chip as one sample. The SIR calculation unit332calculates 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 unit332calculates 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 unit332sums 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 unit334is connected with the SIR calculation unit332. The transmission TPC bit determination unit334calculates a transmission TPC bit based on the SIR from the SIR calculation unit332. For example, the transmission TPC bit determination unit334may calculate a transmission TPC bit so that the SIR from the SIR calculation unit332becomes a predetermined SIR. The transmission TPC bit determination unit334inputs the transmission TPC bit into the encoding unit336.

The encoding unit336is connected with the transmission TPC bit determination unit334. The encoding unit336encodes the transmission TPC bit from the transmission TPC bit determination unit334. The encoding unit336inputs the encoded transmission TPC bit (referred to as the “encoded transmission TPC bit” below) into the modulation unit338.

The modulation unit338is connected with the encoding unit336. The modulation unit338modulates the encoded transmission TPC bit from the encoding unit336. The modulation unit338inputs the modulated encoded transmission TPC bit into the transmission unit342.

The transmission unit342is connected with the modulation unit338and the transmission power calculation unit340. The transmission unit342executes a process for transmitting the modulated encoded transmission TPC bit from the modulation unit338based on information about a calculation result of transmission power from the transmission power calculation unit340. When executing the process for transmitting the encoded transmission TPC bit, the transmission unit342controls transmission timing following a transmission timing signal from the despreading unit318.

FIG. 7is a timing chart of a transmission power control process in the wireless apparatus100according to the present embodiment. InFIG. 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 RFIC200receives the downlink DPCH700, and generates a DigRF packet. The RFIC200transmits the DigRF packet to the baseband processing apparatus300(702). Note that if an error is detected in the DigRF packet, the baseband processing apparatus300executes a retransmission control process of the data. However, the baseband processing apparatus300calculates a transmission TPC bit without waiting for the arrival of the retransmission data by the retransmission control.

The baseband processing apparatus300determines the error symbol location of the DigRF packet (704). Next, the baseband processing apparatus300calculates 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 apparatus300maps the transmission TPC bit into the uplink DPCCH.

The baseband processing apparatus300transmits the uplink DPCCH having the transmission TPC bit mapped to the RFIC200(708).

The RFIC200transmits the uplink DPCCH from the baseband processing apparatus300.

By calculating the transmission TPC bit without waiting for the arrival of the retransmission data by the retransmission control, the wireless apparatus100can 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 RFIC200, the baseband processing apparatus300in the wireless apparatus100can 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 apparatus100by the other wireless apparatus, especially by a base station.

FIG. 8is a flowchart of a process for calculating an SIR according to the present embodiment.FIG. 8mainly illustrates a process executed by the error symbol part determination unit308, the pilot symbol range specification unit316, and the SIR calculation unit332.

At Step S804, the SIR calculation unit332receives a DigRF packet from the retransmission control unit306.

At Step S806, the SIR calculation unit332counts the number of DigRF packets from the retransmission control unit306.

At Step S808, the error symbol part determination unit308determines whether an error is detected in the DigRF packet based on error DigRF packet information from the retransmission control unit306.

At Step S810, if it is determined at Step S808that an error is detected in the DigRF packet, the pilot symbol range specification unit316counts the number of DigRF packets in which errors are detected. Specifically, the pilot symbol range specification unit316sets “1” to a part corresponding to the DigRF packet in which an error is detected in the table illustrated inFIG. 4for counting the number of DigRF packets in which errors are detected.

At Step S812, if it is determined at Step S808that an error is not detected in the DigRF packet, the following steps are executed. Namely, the pilot symbol range specification unit316sets “0” to the part corresponding to the DigRF packet in which an error is not detected in the table illustrated inFIG. 4. After that, the pilot symbol range specification unit316determines whether the number of DigRF packets reach 32. The pilot symbol range specification unit316may determine whether the number of chips reach 256.

The following is also executed in Step S812after setting “1” to the part corresponding to the DigRF packet in which the error is detected. Namely, the pilot symbol range specification unit316determines whether the number of DigRF packets reach 32. The pilot symbol range specification unit316may determine whether the number of chips reach 256.

At Step S814, if it is determined at Step S812that the number of DigRF packets reach 32, the SIR calculation unit332calculates an SIR. The SIR calculation unit332calculates 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 unit332sums the calculation results of the likelihood. Namely, the SIR calculation unit332sums 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 S812that the number of DigRF packets does not reach 32, the process goes back to Step S804.

At Step S816, the SIR calculation unit332executes an averaging process of the SIR. Namely, the SIR calculation unit332obtains the number of samples by excluding DigRF packets in which errors are detected, from the 32 DigRF packets. The SIR calculation unit332executes the averaging process of the SIR by dividing the total value of the likelihood by the number of samples.

<Operations of Wireless Apparatus100>

FIGS. 9A-9Billustrate operations of the wireless apparatus100according to the present embodiment.

The wireless apparatus100operates in accordance with DigRF v4.

At Step S902, the RFIC200receives a wireless signal from the other wireless apparatus. Namely, the retransmission control unit208receives IQ data as input from the RxADC202.

At Step S904, the retransmission control unit208executes buffering of the IQ data, and inputs the IQ data to the LVDS driver212.

At Step S906, the LVDS driver212generates a DigRF packet of the IQ data from the retransmission control unit208. The LVDS driver212outputs the DigRF packet to the LVDS receiver304.

At Step S908, the LVDS receiver304receives the DigRF packet from the RFIC200. The LVDS receiver304inputs the DigRF packet from the RFIC200into the retransmission control unit306.

At Step S910, the retransmission control unit306determines whether a data error is detected in the DigRF packet from the LVDS receiver304.

At Step S912, if a data error is detected in the DigRF packet from the LVDS receiver304at Step S910, the error symbol part determination unit308determines the symbol in which the error is detected. The error symbol part determination unit308inputs the error symbol information into the pilot symbol range specification unit316.

At Step S914, the pilot symbol range specification unit316specifies the range of pilot symbols used for calculating the transmission TPC bit based on the error symbol information from the error symbol part determination unit308. The pilot symbol range specification unit316inputs the pilot symbol range information into the SIR calculation unit332.

At Step S916, the SIR calculation unit332executes an SIR calculation process.

At Step S918, the transmission TPC bit determination unit334calculates the transmission TPC bit based on the SIR calculated by the SIR calculation unit332.

At Step S920, the modulation unit338executes a modulation process of the IQ data to be transmitted.

At Step S922, the transmission unit342transmits the transmission TPC bit calculated by the transmission TPC bit determination unit334and the IQ data modulated at Step S920.

At Step S924, the retransmission control unit314makes a retransmission-request of the DigRF packet.

At Step S926, the LVDS driver312generates a DigRF packet of the retransmission-request signal from the retransmission control unit314. The LVDS driver312transmits the DigRF-packeted retransmission-request signal to the RFIC200.

At Step S928, the LVDS receiver214receives the DigRF-packeted retransmission-request signal from the LVDS driver312. The LVDS receiver214inputs the retransmission-request signal into the retransmission control unit210.

At Step S930, the retransmission control unit210makes a retransmission-request to the retransmission control unit208based on the retransmission-request signal from the LVDS receiver214. In response to the retransmission-request from the retransmission control unit210, the retransmission control unit208inputs the IQ data to be retransmitted into the LVDS driver212.

At Step S932, the LVDS driver212generates a DigRF packet of the IQ data from the retransmission control unit208for retransmission. The LVDS driver212outputs the DigRF packet to the LVDS receiver304.

At Step S934, the LVDS receiver304receives the DigRF packet from the RFIC200. The LVDS receiver304inputs the DigRF packet from the RFIC200into the buffer310via the retransmission control unit306.

At Step S936, the buffer310replaces IQ data among the stored IQ data that corresponds to the IQ data retransmitted from the retransmission control unit306. Namely, the buffer310updates the IQ data among the stored IQ data that corresponds to the IQ data retransmitted from the retransmission control unit306. The buffer310inputs the stored IQ data into the despreading unit318.

At Step S938, the despreading unit318executes a despreading process for the IQ data from the buffer310.

At Step S940, the CPICH demodulation unit320demodulates the CPICH. Also, at Step S940, the DPCH demodulation unit320demodulates the DPCH.

At Step S942, the LVDS driver312generates a DigRF packet of the IQ data transmitted from the transmission unit342. The LVDS driver312transmits the DigRF-packeted IQ data to the LVDS receiver214.

At Step S944, the LVDS receiver214receives the DigRF packet from the baseband processing apparatus300. The LVDS receiver214converts the DigRF packet from the baseband processing apparatus300into IQ data. The LVDS receiver214inputs the IQ data into the TxDAC204via the retransmission control unit210.

At Step S946, the TxDAC204transmits the IQ data from the LVDS receiver214.

By the operations of the wireless apparatus100in the present embodiment illustrated inFIGS. 9A-9B, the transmission TPC bit is calculated without waiting for the arrival of the retransmission data by the retransmission control. Therefore, the wireless apparatus100can shorten time for transmitting the uplink DPCCH having the transmission TPC bit mapped after the reception of a pilot.

FIG. 10illustrates 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.

InFIG. 10, similarly toFIG. 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 DPCH1000, 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 box1002includes 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 inFIG. 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 RFIC200, 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.