JP2009049774A - Radio communication device, diversity reception control method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a diversity reception device to reduce power consumption and to improve communication call maintenance performance concurrently through start/stop switchover to a diversity reception operation from a communication state in an individual channel alone. <P>SOLUTION: Communication quality is measured and start/stop switchover to a diversity reception operation is controlled from a communication state in an individual channel, based on the relation between a measured value and a target value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radio communication apparatus, a diversity reception control method, and a program having a function of performing diversity reception using a plurality of reception antennas such as a mobile phone terminal and a WCDMA (Wideband-Code Division Multiple Access) reception apparatus.

  Generally, in mobile communication, reception performance is degraded due to fading due to multiwave interference. In order to reduce the influence of fading, a diversity reception system is used in which reception is performed using a plurality of branches that are independent in space, polarization, angle, frequency, or time.

  Spatial diversity is conventionally known as a method for improving reception quality characteristics by rake combining received signals received from two or three or more antennas. However, finger and path search processing corresponding to two antennas is required, and there is a concern about an increase in the HW scale.

  In recent years, due to the operation of the high-speed downlink packet communication system (HSDPA), the data reception performance at the mobile device is important, and the opportunity to apply space diversity reception to the mobile device has increased. This is because in HSDPA, data communication is performed at a higher rate to a terminal having good reception quality.

  Further, as a related invention for performing such diversity reception, spread modulation waves are received for each of two or more antenna branches, and received in order from the antenna branch having the smallest maximum or average signal-to-interference ratio for the selected path. And there is one that stops path selection (see, for example, Patent Document 1).

In addition, there is a technique that operates diversity reception during communication using a control channel (common channel) and stops diversity reception during communication using a dedicated channel such as a call (for example, see Patent Document 2).
JP 2006-80910 A JP 2006-324816 A

  However, in space diversity reception, there is a problem that the current consumption of the wireless terminal increases due to two systems of radio circuits and demodulation processing, and the standby time and call time decrease.

  The above-mentioned Patent Documents 1 and 2 switch diversity reception operation / non-operation between a dedicated channel used for a call and the like and a control channel (common channel). It was not even considered for switching.

  The present invention has been made in view of such a situation, and by switching the start / stop of the diversity reception operation from the communication state of the individual channel alone, the current consumption can be reduced and the communication call maintaining performance in the diversity receiver. An object of the present invention is to provide a wireless communication device, a diversity reception control method, and a program that can achieve both improvement of the above.

  In order to achieve this object, a wireless communication apparatus according to the present invention receives diversity reception from a communication state in an individual channel based on a measurement unit that measures communication quality, and a relationship between a measurement value and a target value by the measurement unit. Switching control means for performing switching control of operation start / stop.

  Also, the diversity reception control method according to the present invention starts / stops the diversity reception operation based on the measurement step of measuring communication quality and the relationship between the measurement value and the target value in the measurement step from the communication state in the individual channel. And a switching control step for performing the switching control.

  Further, the diversity reception control program according to the present invention provides a computer of a wireless communication apparatus having a plurality of reception channels, a measurement process for measuring communication quality, and a measurement value and a target by the measurement process based on a communication state in an individual channel. And a switching control process for performing switching control of start / stop of the diversity reception operation based on the relationship of values.

  As described above, according to the present invention, by switching the start / stop of the diversity reception operation from the communication state of the dedicated channel alone, it is possible to simultaneously reduce the current consumption and improve the communication call maintenance performance in the diversity receiver. Can be made.

Next, an embodiment in which a radio communication apparatus, a diversity reception control method, and a program according to the present invention are applied to a CDMA reception apparatus will be described in detail with reference to the drawings.
First, an outline of the present embodiment will be described.

  The diversity reception operation switching control method according to the present embodiment is a diversity reception apparatus that monitors communication quality and performs diversity operation switching control according to the communication quality status.

For this reason, the apparatus for performing diversity reception according to the present embodiment is a diversity reception apparatus having a control function for performing and stopping diversity reception according to communication conditions, and a target SIR (target value) and measured SIR (during individual channel communication). Means for controlling the switching of the diversity operation from the following state of the measured value).
This makes it possible to temporarily stop diversity reception when the received signal quality exceeds a predetermined threshold value, and to achieve both reduction in current consumption and improvement in communication call maintenance performance in the diversity receiver.

Next, the configuration of the CDMA receiver according to this embodiment will be described with reference to FIG.
As shown in FIG. 1, the CDMA receiver according to this embodiment includes two systems of antennas 1A and 1B. Signals received by the antennas 1A and 1B are converted into baseband received signals by the two RF units 2A and 2B. Thus, the antenna 1A and the antenna 1B function as receiving means for receiving a radio signal.

  Two systems of AGC units (automatic gain control units) 3A and 3B measure the strength (RSSI) of the baseband received signal and control the gains of the RF units 2A and 2B. The path search unit 5 detects the path timing from the two received signals and notifies the finger rake combining unit 6 of the path timing. The path search unit 5 creates power delay profiles of two received signals in order to detect path timing.

  The finger rake combining unit 6 performs despreading processing and rake combining processing on the two received signals, and outputs received symbol data to the data decoding unit 7. The finger rake combining unit 6 measures SIR (Signal to Interference Ratio) from the despread pilot signal and interference signal for each individual channel (measuring means). Then, the finger rake combiner 6 generates a TPC (Transmission Power Control) command for transmission power control so that the measurement SIR follows the target SIR.

  The data decoding unit 7 decodes the received symbol data and outputs decoded data. The diversity reception control unit (switching control unit) 4 inputs the target SIR and measurement SIR information from the finger rake combining unit 6, performs diversity operation determination, and performs antenna 1B, RF unit 2B, path search unit 5, finger rake combining. Diversity switching signals are output to the units 6 respectively.

  In addition to the configuration shown in FIG. 1, the CDMA receiver according to the present embodiment includes an upper layer (not shown) such as a CPU, and acquires information such as the target SIR from the upper layer, thereby obtaining the information shown in FIG. The apparatus configuration shown in FIG.

The target SIR is calculated by adjusting the target SIR so that the measured BLER (measured block error rate) of the wireless communication device matches the BLER quality value (target quality) instructed from the wireless network control device. That is, an upper layer such as a CPU calculates the target SIR based on the value of the target BLER quality received from the radio network controller that performs radio communication with the CDMA receiver according to the present embodiment.
By lowering the target SIR, the transmission power of the base station decreases and the measurement BLER of the receiving apparatus increases, and by increasing the target SIR, the transmission power of the base station increases and the measurement BLER of the receiving apparatus decreases. (Reference: 3GPP TS24.331 14.9. Downlink power control)

Next, the operation of the CDMA receiver according to this embodiment will be described.
The received signals received by the two systems of antennas 1A and 1B shown in FIG. 1 are converted into baseband signals by the RF systems 2A and 2B such as the second system, respectively. The two systems of received signals are AGC controlled independently by the respective AGC units 3A and 3B.
For this reason, AGC control is optimally performed in different fading environments between the antenna 1A and the antenna 1B, and the baseband received signal is input to the digital baseband signal processing unit.

The RF unit 2B and the AGC unit 3B are controlled to operate or stop operating according to a control signal from the diversity reception control unit 4.
When the RF unit 2B and the AGC unit 3B are in the operation stop state, the power supply to the RF unit 2B and the AGC unit 3B is stopped to reduce current consumption.

  The path search unit 5 receives two baseband received signals, detects a path timing from each received signal, and notifies the finger rake combining unit 6 of the detected path timing. The finger rake combiner 6 receives two baseband received signals, and outputs a demodulated signal (received symbol data) obtained by rake combining the respective signals to the data decoder 7.

  The path search unit 5 and the finger rake unit 6 control whether or not to perform an operation on the input signal on the RF unit 2B side by a control signal from the diversity reception control unit 4. When the operation on the input signal on the RF unit 2B side is stopped, the amount of processing is reduced, so that an effect of reducing current consumption can be obtained.

  The finger rake combining unit 6 generates a TPC (Transmission Power Control) command for downlink transmission power control for the communication quality (measurement SIR) of the dedicated channel. The TPC command is generated so that a target SIR given from an upper layer (not shown) is equal to a measurement SIR measured from the received signal. The target SIR is sequentially updated from the upper layer from the target reception quality and reception error rate.

  Further, the finger rake combining unit 6 outputs the target SIR and the measurement SIR to the diversity reception control unit 4. The diversity reception control unit 4 determines the diversity operation from the target SIR and measurement SIR input from the finger rake combining unit 6, and switches the diversity operation to the antenna 1B, the RF unit 2B, the path search unit 5, and the finger rake combining unit 6, respectively. Output a signal.

A method of switching the diversity operation will be described with reference to the flowchart shown in FIG.
In step S1 of FIG. 2, it is determined whether or not the diversity operation is currently being performed. If the diversity operation is not being performed, the process proceeds to step S2, and if the diversity operation is being performed, the process proceeds to step S4. In step S2, the difference between the target SIR and the measurement SIR is compared with the ON threshold. If the difference between the target SIR and the measurement SIR is larger than the ON threshold, it is determined in step S3 that the diversity reception operation starts. In step S4, the difference between the target SIR and the measurement SIR is compared with the OFF threshold value. If the difference between the target SIR and the measurement SIR is smaller than the OFF threshold value, it is determined in step S5 that the diversity operation is stopped.
The above-described ON threshold value and OFF threshold value may be predetermined values or may be calculated by a predetermined calculation method.

Next, a switching operation example of the diversity reception operation will be described using the timing chart shown in FIG.
Usually, transmission power control is performed by a radio network controller or the like so that the measurement SIR follows the vicinity of the target SIR. However, there is a case where the measurement SIR falls because the transmission power control is not effective due to deterioration of the communication environment or the like. Thus, when it is detected that the difference between the target SIR and the measurement SIR exceeds the ON threshold at the point of time A in FIG. 3, the diversity reception operation is started. Thereafter, when the measurement SIR rises at the point of time B and it is detected that the difference between the target SIR and the measurement SIR is smaller than the OFF threshold, the diversity reception operation is stopped.

  As described above, the embodiment described above monitors the difference between the target SIR and the measurement SIR used for downlink transmission power control in the communication state on the dedicated channel, with respect to the diversity reception operation start / stop switching control method. When this difference exceeds the threshold value, the diversity reception operation is started. If this difference is smaller than the threshold value, the diversity operation is stopped.

In this way, in the individual channel communication state to which transmission power control is applied, in a normal state where transmission power control is effective, when diversity reception is stopped and the communication environment is such that transmission power control is not effective. Only the diversity reception operation is performed to improve the reception performance and reduce the call connection disconnection probability.
In this way, regardless of the control channel (common channel), the diversity reception operation start / stop switching control is performed on the basis of the SIR characteristics for each individual channel, thereby reducing current consumption and improving communication call maintenance performance. Both can be achieved.

[Other Embodiments]
Next, another embodiment of the present invention will be described. In the other embodiments, the basic configuration is the same as that of the above-described embodiment, but the diversity reception operation switching method is further devised.
That is, as compared with the embodiment described above, the diversity reception operation is switched from the synchronization determination result instead of determining from the difference between the target SIR and the measurement SIR.

  In the individual channel, synchronization determination processing is always performed for radio link monitoring. In the synchronization determination processing, the diversity reception control unit 4 determines synchronization based on the quality (measurement SIR) of the DPCCH (Dedicated Physical Control Channel) and the decoding result (CRC OK / NG) of the received signal, and the synchronization determination result Is sent to the upper layer.

  A switching example of the diversity reception operation will be described using the timing chart shown in FIG. In the example shown in FIG. 4, as the synchronization determination process, the synchronization is determined to be out of synchronization when the measured SIR measured by the finger rake unit synthesizing unit 6 is less than the Qout threshold, and the synchronization is determined to be in the synchronization determination process.

  The Qout threshold value and the Qin threshold value may be switched in accordance with the slot format of the communication channel within the apparatus. That is, the Qout threshold and the Qin threshold are calculated by an upper layer such as a CPU based on the error rate of the TPC command (threshold calculation means). (Reference: 3GPP TS25.101 6.4.4 Out-of-synchronization handling of output power)

As another configuration, if the decoding result of the received data is a certain amount of NG, the synchronization is lost, and if the decoding result is OK, it is determined to be synchronization (not shown). That is, if the ratio of decoding failure in the decoding result of received data is equal to or greater than a predetermined threshold value, the synchronization is lost, and if it is less than the threshold value, it is determined to be synchronous.
In the case of this configuration, a functional part that measures the rate of decoding failure in the decoding result of received data, such as the finger rake unit synthesizing unit 6, becomes a measuring unit that measures communication quality.
Further, the threshold value used for the determination may be determined in advance or may be calculated by a predetermined calculation method.

When synchronous / asynchronous is determined by each of the above configurations, the determination result is input to the diversity reception control unit 4.
When the diversity reception control unit 4 receives the result of the synchronization determination process and detects a loss of synchronization, it determines that the diversity operation is started. Further, when the synchronization determination processing result is received and synchronization is detected, it is determined that the diversity operation is stopped. As a result, the diversity reception control unit 4 outputs a diversity operation switching signal to the antenna 1B, the RF unit 2B, the path search unit 5, and the finger rake combining unit 6, respectively.

  As described above, in the other embodiments described above, with regard to the diversity reception operation start / stop switching control method, if out-of-synchronization is detected based on the synchronization determination result detected in the downlink synchronization determination processing in the communication state on the dedicated channel. The diversity reception operation is started, and when the synchronization is detected, the diversity operation is stopped.

As described above, in the other embodiments described above, in the individual channel communication state to which the transmission power control is applied, based on the synchronization determination result, the diversity reception is stopped in the normal state in which the transmission power control is effective. Diversity reception operation is performed only in a communication environment in which transmission power control does not work, improving reception performance and reducing call connection disconnection probability.
Thus, regardless of the control channel (common channel), the diversity reception operation start / stop switching control is performed based on the synchronization determination result for each individual channel, thereby reducing current consumption and improving communication call maintenance performance. Can be made compatible.

Each of the above-described embodiments is a preferred embodiment of the present invention, and the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.
For example, in each of the embodiments described above, it has been described that there are two reception channels provided with antennas. However, the configuration is not limited to this configuration as long as a plurality of reception channels are provided. Good.

  In addition to the configuration shown in FIG. 1, the CDMA receiver as each embodiment includes an upper layer (not shown) such as a CPU, and acquires information such as a target SIR from this upper layer. Although the configuration of the apparatus shown in FIG. 1 has been described as various operations, the configuration is not limited to this configuration as long as information such as the target SIR is input to the configuration shown in FIG. For example, the present invention can be similarly realized even in a system in which an upper layer for calculating the target SIR is provided as another device.

  The target SIR may be calculated as in the above-described embodiment, or may be determined in advance.

  In addition, various control methods may be used as long as the control for temporarily stopping / resuming the diversity reception according to the communication condition is performed instead of the diversity reception. For example, high-speed transmission power control is performed. Control may be performed such that diversity reception is not performed on a dedicated channel.

  In the above-described embodiment, the wireless communication apparatus according to the present invention has been described as a CDMA receiver. However, the present invention is not limited to this as long as the apparatus has a function of performing diversity reception using a plurality of reception antennas. Instead, various wireless communication devices such as various mobile phone terminals may be used.

Further, by recording the processing procedure for realizing the CDMA receiver as each embodiment described above as a program on the recording medium, the above-described functions according to each embodiment of the present invention are supplied from the recording medium. The program can be realized by causing a CPU of a computer constituting the system to perform processing.
In this case, the present invention can be applied even when an information group including a program is supplied to the output device from the above recording medium or from an external recording medium via a network.
That is, the program code itself read from the recording medium realizes the novel function of the present invention, and the recording medium storing the program code and the signal read from the recording medium constitute the present invention. It will be.
As this recording medium, for example, flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, non-volatile A memory card, ROM or the like may be used.

  According to the program according to the present invention, each function in the CDMA receiver as each embodiment according to the present invention described above can be realized in the wireless communication apparatus controlled by the program.

It is a block diagram which shows the example of a principal part structure of the CDMA receiver as embodiment of this invention. It is a flowchart which shows switching control of the start / stop of a diversity reception operation. It is a timing chart which shows switching control of the start / stop of a diversity reception operation. It is a timing chart which shows the start / stop switching control of the diversity reception operation according to another embodiment.

Explanation of symbols

1 Antenna 4 Diversity Reception Control Unit 5 Path Search Unit 6 Finger Lake Combining Unit 7 Data Decoding Unit

Claims (24)

Measuring means for measuring communication quality;
And a switching control unit that performs switching control of start / stop of a diversity reception operation from a communication state in an individual channel based on a relationship between a measured value and a target value by the measuring unit. . The switching control means includes
When the difference between the measured value and the target value is greater than or equal to a predetermined threshold, a diversity reception operation is performed,
The radio communication apparatus according to claim 1, wherein the diversity reception operation is stopped when a difference between the measured value and the target value is less than a predetermined threshold. The target value is defined by an out threshold value and an in threshold value,
The switching control means includes
When the measured value is less than the out threshold value, a diversity reception operation is started,
The radio communication apparatus according to claim 1, wherein the diversity reception operation is stopped when the measured value is equal to or greater than the in threshold value. The target value is defined by whether or not it is a predetermined threshold value or more,
The switching control means includes
When the measurement result by the measurement means is equal to or greater than the threshold value, a diversity reception operation is performed,
The radio communication apparatus according to claim 1, wherein the diversity reception operation is stopped when a measurement result by the measurement unit is less than the threshold value.   3. The wireless communication apparatus according to claim 2, further comprising target value calculation means for calculating the target value based on a value received from another apparatus.   4. The wireless communication apparatus according to claim 3, further comprising threshold value calculating means for calculating the out threshold value and the in threshold value based on a command error rate.   5. The wireless communication apparatus according to claim 4, wherein the measuring unit measures the communication quality based on a decoding failure rate in a decoding result of received data.   The wireless communication apparatus according to claim 1, wherein the measurement unit measures the communication quality by SIR (Signal to Interference Ratio). A measurement process for measuring communication quality;
A diversity reception control comprising: a switching control step for performing switching control of start / stop of a diversity reception operation based on a relationship between a measurement value and a target value in the measurement step based on a communication state in an individual channel. Method. In the switching control step,
When the difference between the measured value and the target value is greater than or equal to a predetermined threshold, a diversity reception operation is performed,
The diversity reception control method according to claim 9, wherein the diversity reception operation is stopped when a difference between the measured value and the target value is less than a predetermined threshold. The target value is defined by an out threshold value and an in threshold value,
In the switching control step,
When the measured value is less than the out threshold value, a diversity reception operation is started,
The diversity reception control method according to claim 9, wherein the diversity reception operation is stopped when the measured value is equal to or greater than the in threshold value. The target value is defined by whether or not it is a predetermined threshold value or more,
In the switching control step,
When the measurement result by the measurement step is equal to or greater than the threshold, a diversity reception operation is performed,
The diversity reception control method according to claim 9, wherein the diversity reception operation is stopped when a measurement result in the measurement step is less than the threshold value.   The diversity reception control method according to claim 10, further comprising a target value calculation step of calculating the target value based on a value received from another device.   12. The diversity reception control method according to claim 11, further comprising a threshold value calculation step of calculating the out threshold value and the in threshold value based on a command error rate.   13. The diversity reception control method according to claim 12, wherein, in the measurement step, the communication quality is measured based on a decoding failure rate in a decoding result of received data.   15. The diversity reception control method according to claim 9, wherein in the measurement step, the communication quality is measured by SIR (Signal to Interference Ratio). In a computer of a wireless communication device having a plurality of reception channels,
A measurement process to measure communication quality;
Diversity reception control, wherein switching control processing for performing switching control of start / stop of diversity reception operation based on a relationship between a measurement value and a target value by the measurement processing is performed based on a communication state on an individual channel. program. In the switching control process,
When the difference between the measured value and the target value is greater than or equal to a predetermined threshold, a diversity reception operation is performed,
18. The diversity reception control program according to claim 17, wherein a diversity reception operation is stopped when a difference between the measured value and the target value is less than a predetermined threshold value. The target value is defined by an out threshold value and an in threshold value,
In the switching control process,
When the measured value is less than the out threshold value, a diversity reception operation is started,
18. The diversity reception control program according to claim 17, wherein the diversity reception operation is stopped when the measured value is equal to or greater than the in threshold value. The target value is defined by whether or not it is a predetermined threshold value or more,
In the switching control process,
When a measurement result by the measurement process is equal to or greater than the threshold, a diversity reception operation is performed,
The diversity reception control program according to claim 17, wherein the diversity reception operation is stopped when a measurement result by the measurement process is less than the threshold value.   19. The diversity reception control program according to claim 18, further comprising a target value calculation process for calculating the target value based on a value received from another device.   20. The diversity reception control program according to claim 19, further comprising a threshold value calculation process for calculating the out threshold value and the in threshold value based on an error rate of a command.   21. The diversity reception control program according to claim 20, wherein, in the measurement process, the communication quality is measured based on a decoding failure rate in a reception data decoding result.   The diversity reception control program according to any one of claims 17 to 22, wherein, in the measurement process, the communication quality is measured by SIR (Signal to Interference Ratio).

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