Mobile station device, and method of transmitting channel quality information

The present invention relates to a mobile station apparatus and a method of transmitting channel quality information. In particular, it is preferably used for transmission of a channel quality indicator (CQI) when intermittent reception (DRX) control is performed in a radio resource management (RRC) connection between a radio base station and a mobile station device. Is.

3GPP (3), an international standardization body for third-generation mobile phone systems^rd The Generation Partnership Project) is studying a wireless communication system using LTE (Long Term Evolution), which is a new communication standard between wireless base stations and mobile station devices. One of the functions of the wireless communication system is intermittent reception (DRX) control in the wireless resource management (RRC) connection.

Intermittent reception (DRX) control is a function aimed at power saving, and Fig. 3 shows an outline of the operation of intermittent reception (DRX) control. The mobile station device intermittently receives the downlink control channel (PDCCH: Physical Downlink Control Channel), monitors the downlink control channel (PDCCH) from the serving base station only during the on-duration 3-1 period, and addresses it to its own station. Monitor for the presence of data.

Then, during the period of the intermittent reception opportunity (Opportunity for DRX) 3-2 shown in FIG. 3, the downlink control channel (PDCCH) from the serving base station is not monitored, and the different frequency signal is measured for handover. The intermittent reception cycle (DRX Cycle) 3-3 is composed of two periods, the on-duration period 3-1 and the intermittent reception opportunity (Opportunity for DRX) period 3-2, and this intermittent reception cycle (DRX Cycle). ) Intermittent reception is repeated in 3-3.

In addition, in order to perform link adaptation (for example, transmission power control, adaptive modulation coding, etc.) that follows high-speed fading, the mobile station device provides a channel quality indicator (CQI) that indicates the status of the radio channel to the serving base station. Send repeatedly.

Figure 4 shows an example of the transmission operation of the channel quality indicator (CQI). In the figure, (a) shows the monitoring period of the intermittent reception cycle (DRX Cycle). (b) shows each subframe of the downlink control channel (PDCCH). (c) shows the transmission scheduling signal of the channel quality indicator (CQI). (d) indicates the measurement period of channel quality. (e) indicates each subframe of the uplink control channel (PUCCH).

The mobile station device monitors the downlink control channel (PDCCH) only during the on-duration period, which is the monitoring period, and in the example of FIG. 4, the subframe number is the period from 01 to 06. In addition, since the period during which the mobile station device can transmit control data on the uplink control channel (PUCCH) is defined as the same period as the monitoring period on the downlink control channel (PDCCH), the uplink control channel (PUCCH) The subframe number of is the period from 01 to 06.

The timing of transmitting channel quality indicator (CQI) information on the uplink control channel (PUCCH) is scheduled according to the instruction from the base station. For example, uplink control is performed at the timing indicated by the CQI transmission scheduling signal shown in FIG. 4 (c). Sent in subframes of the channel (PUCCH).

In the example of FIG. 4, the transmission timing of the channel quality indicator (CQI) indicated by the CQI transmission scheduling signal is the timing of the subframe numbers 02 and 07, but the transmittable period of the uplink control channel (PUCCH) is , Since it is the period from subframe number 01 to 06 of the on-duration period, the channel quality indicator (CQI) is actually transmitted only to the subframe of subframe number 02.

Intermittent reception (DRX) control is described in Non-Patent Document 1 and the like below. Further, the transmission of the channel quality indicator (CQI) is described in, for example, the following Patent Documents 1 and 2.<nplcit num="1"><text>3GPP TS36.300 V8.5.0 (2008-05)</text></nplcit><patcit num="1"><text>Japanese Patent Application Laid-Open No. 2007-202096</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2008-54125</text></patcit>

<p> When the mobile station device receives the downlink control channel (PDCCH) addressed to its own station during the monitoring period (on duration period), the mobile station device activates the Inactivity Timer to activate the inactivity timer (PDCCH). Extend the monitoring period of the downlink control channel (PDCCH) until the timed period by the Inactivity Timer) expires. An example of this operation is shown in Fig. 5.</p><p> In FIG. 5, (a) shows the monitoring period of the intermittent reception cycle (DRX Cycle). (b) shows each subframe of the downlink control channel (PDCCH). (a') indicates the output signal of the Inactivity Timer. (c) shows the transmission scheduling signal of the channel quality indicator (CQI). (d) indicates the measurement period of channel quality. (e) indicates each subframe of the uplink control channel (PUCCH).</p><p> In FIG. 5, assuming that control data addressed to the own station is received in the subframe of subframe number 06 of the downlink control channel (PDCCH), the mobile station apparatus has an inactivation timer (Inactivity) as shown in (a'). The Timer is activated, and the monitoring period of the downlink control channel (PDCCH) is extended to the expiration of the time counting period by the inactivity timer, that is, to the subframe number 13.</p><p> Since the transmittable period of the uplink control channel (PUCCH) is the same as the monitor period of the downlink control channel (PDCCH), the uplink control channel (PUCCH) is also extended to subframe number 13 and subframe numbers 01 to 13. The period is the transmittable period. In this case, the channel quality indicator (CQI) is transmitted on the uplink control channel (PUCCH) subframe numbers 02,07,12 according to the instruction of the CQI scheduling signal.</p><p> In the case of the operation example of FIG. 5, it is determined whether or not the control data received at the timing of subframe number 06 is addressed to the own station, and if it is not addressed to the own station, the subframe number is as shown in the operation example of FIG. If the channel quality indicator (CQI) is not transmitted at 07 and it is addressed to your own station, the channel quality indicator (CQI) will be transmitted at the timing of subframe number 07 immediately after that.</p><p> However, determining whether the control data received at the timing of subframe number 06 is addressed to the own station and transmitting the channel quality indicator (CQI) at the timing of subframe number 07 immediately after that requires processing time. It is difficult in terms of time due to constraints.</p><p> In this way, in the subframe immediately before the end of the monitor period (on duration period) of the intermittent reception cycle (DRX Cycle), the control data addressed to the own station is received from the downlink control channel (PDCCH), and the subframe immediately after that. If the schedule is to send the channel quality indicator (CQI) in, it may not be possible to send the channel quality indicator (CQI) in the subframe immediately after that.</p><p> Therefore, there may be cases where the channel quality indicator (CQI) cannot be transmitted even though it is the period during which the channel quality indicator (CQI) should be transmitted. Therefore, accurate wireless link control cannot be performed due to the lack of the channel quality indicator (CQI). Therefore, the purpose is to enable accurate channel quality information to be transmitted even when channel quality information (for example, channel quality indicator: CQI) transmission is missing.</p>

<p> When the control data of the downlink control channel is destined for the own station, the mobile station apparatus as the first mode for solving the above problem extends the monitoring period and transmits the channel quality information in the extended monitoring period. At that time, the channel quality information transmission determining means for determining the timing when the channel quality information cannot be transmitted and the channel quality information to be transmitted at the timing when the channel quality information cannot be transmitted are transmitted at the timing when the channel quality information can be transmitted next. It is provided with a means for processing channel quality information to be reflected in the channel quality information to be processed.</p><p> In the second mode, the channel quality information transmission method is to extend the monitoring period when the control data of the downlink control channel is addressed to the own station, and transmit the channel quality information in the extended monitoring period. At that time, the first step of determining the timing when the channel quality information cannot be transmitted and the value of the channel quality information to be transmitted at the timing when the channel quality information cannot be transmitted are transmitted at the timing when the channel quality information can be transmitted next. It includes a second step, which is reflected in the value of the channel quality information.</p>

<p> According to the disclosed mobile station device and channel quality information transmission method, accurate channel quality information can be transmitted even when channel quality information (for example, channel quality indicator: CQI) transmission is missing. ..</p>

Figure 1 shows an example of the transmission operation of the disclosed channel quality information. The channel quality indicator (CQI) will be described below as an example of channel quality information. In the figure, (a) shows the monitoring period of the intermittent reception cycle (DRX Cycle). (b) shows each subframe of the downlink control channel (PDCCH). (a') indicates the output signal of the Inactivity Timer. (c) shows the transmission scheduling signal of the channel quality indicator (CQI). (d) indicates the measurement period of channel quality. (e) indicates each subframe of the uplink control channel (PUCCH).

In the operation example of FIG. 1, the same operation as that of FIG. 5 will not be described. In FIG. 1, when a situation such as subframe number 07 in which the channel quality indicator (CQI) should be transmitted but cannot be transmitted occurs, the subframe number 07 is attempted to be transmitted. Instead of discarding the used channel quality indicator (CQI), it is reflected in the channel quality indicator (CQI) to be transmitted at the next transmittable subframe number 12 and transmitted.

Figure 2 shows a configuration example of the transmission function of the channel quality indicator (CQI). In this configuration example, a configuration example is shown in which the missing channel quality indicator (CQI) is reflected on average with the channel quality indicator (CQI) to be transmitted next.

In FIG. 2, the on-duration timer 2-1 sends a signal indicating the monitoring period (on-duration period) of the downlink control channel (PDCCH) in the intermittent reception cycle (DRX Cycle) to the PDCCH monitor unit 2-2. To do.

The PDCCH monitor unit 2-2 inputs the downlink control channel (PDCCH) signal during the monitoring period indicated by the output signal of the on-duration timer 2-1 and the downlink control channel (PDCCH) data is its own station. Determine if the data is addressed.

If the data on the downlink control channel (PDCCH) is destined for the own station, the Inactivity Timer section 2-3 is requested to start the timer. The Inactivity Timer unit 2-3 outputs a signal indicating the monitor extension period when the timer is activated.

The PDCCH monitor unit 2-2 receives signals from the on-duration timer 2-1 and the inactivity timer unit 2-3 indicating the monitoring period and extension period of the downlink control channel (PDCCH). The period indicated by the logical sum signal of both signals that are input is the downlink control channel (PDCCH) monitoring period.

The CQI transmission scheduling unit 2-4 outputs a signal indicating the transmission timing of the channel quality indicator (CQI) at the timing instructed by the control signal from the serving base station to the CQI measurement unit 2-5 and the CQI transmission determination unit 2-6. Output to.

CQI measurement unit 2-5 inputs a reference signal for measuring the status of the radio channel with the serving base station, measures the channel quality of the radio channel according to the transmission schedule signal of the channel quality indicator (CQI), and channels. The quality indicator (CQI) is calculated and output to the CQI average processing unit 2-7.

The CQI transmission determination unit 2-6 contains a signal indicating the period during which the channel quality indicator (CQI) output from the on-duration timer 2-1 and the inactivity timer (Inactivity Timer) unit 2-3 should be transmitted. The channel quality indicator (CQI) transmittable subframe is determined based on the channel quality indicator (CQI) transmit subframe position information output from the CQI transmission scheduling unit 2-4, and the channel quality indicator (CQI) transmittable subframe information is determined. Is output to the PUCCH generator 2-8.

In addition, the CQI transmission determination unit 2-6 inputs information on the activation determination timing (determination timing of the downlink control channel addressed to its own station) when the Inactivity Timer unit 2-3 is activated, and the relevant information is input. For the channel quality indicator (CQI) transmission subframe position information at the timing when there is not a sufficient processing period from the start judgment timing, it is judged that transmission is not possible, and the judgment result is notified to the CQI average processing unit 2-7. To do.

In the CQI averaging unit 2-7, when the channel quality indicator (CQI) transmission subframe position information that cannot be transmitted is input from the CQI transmission determination unit 2-6, the value of the channel quality indicator (CQI) at that time is set. The operation is performed to hold and average the value of the next input channel quality indicator (CQI), and the averaged channel quality indicator (CQI) value is used as the next channel quality indicator (CQI) in PUCCH. Output to generator 2-8.

The CQI averaging unit 2-7 generates PUCCH as it is from the channel quality indicator (CQI) measured by the CQI measurement unit 2-5 when the CQI transmission determination unit 2-6 does not input the transmission failure judgment result. Output to parts 2-8.

The PUCCH generation unit 2-8 sets the channel quality indicator (CQI) output from the CQI averaging unit 2-7 to the corresponding subframe of the uplink control channel (PUCCH) according to the instruction from the CQI transmission determination unit 2-6. Insert and send to the serving base station.

The configuration example in Fig. 2 shows the CQI averaging unit 2-7 as a method for reflecting the channel quality indicator (CQI) at the timing when transmission is not possible to the channel quality indicator (CQI) at the timing when transmission is possible next. This is a configuration example to which the method of averaging and reflecting is applied.

However, the method to reflect is not limited to this, and the data of the value of the channel quality indicator (CQI) at the timing when it cannot be transmitted is converted to the data of the value of the channel quality indicator (CQI) at the timing when it can be transmitted next. It is also possible to apply the method of adding and outputting. That is, it is possible to transmit the data of the value of the channel quality indicator (CQI) at the timing when transmission is not possible together with the data of the value of the next channel quality indicator (CQI) at the timing when it can be transmitted next.

In addition, the average value obtained by weighting the value of the channel quality indicator (CQI) at the timing when transmission is not possible and the value of the channel quality indicator (CQI) at the timing when transmission is possible is calculated, and the average value is calculated. The value can be output as a channel quality indicator (CQI) to be transmitted at the next transmittable timing.

<figref num="1">It is a figure which shows the transmission operation example of the disclosed channel quality indicator (CQI).</figref><figref num="2">It is a figure which shows the configuration example of the transmission function of a channel quality indicator (CQI).</figref><figref num="3">It is explanatory drawing of the intermittent reception (DRX) control.</figref><figref num="4">It is a figure which shows the transmission operation example of a channel quality indicator (CQI).</figref><figref num="5">It is a figure which shows the transmission operation example of the channel quality indicator (CQI) at the time of extension of a monitor period.</figref>

Code description

2-1 On duration timer 2-2 PDCCH monitor 2-3 Inactivity Timer section 2-4 CQI Transmission Scheduling Unit 2-5 CQI measurement unit 2-6 CQI transmission judgment unit 2-7 CQI average processing unit 2-8 PUCCH generator