The present invention relates to a communication terminal apparatus and a base station apparatus, and particularly to a communication terminal apparatus and a base station apparatus in a system that performs high speed packet transmission on the uplink, wherein scheduling is performed by the base station apparatus based on CQI transmitted from the communication terminal apparatus.
To date, in the field of radio communication systems, HSDPA (High Speed Downlink Packet Access) has been standardized where a plurality of communication terminal apparatuses share a downlink channel of high speed and large capacity and high speed packet transmission is performed on the downlink.
In this HSDPA system, a base station apparatus has communication terminal apparatuses transmit a signal indicating the modulation scheme and encoding rate of packet data that can be demodulated in the communication terminal apparatus and being called CQI (Channel Quality Indicator), at a cycle set by the base station apparatus. The base station apparatus having received CQI selects an optimum modulation scheme, encoding rate and the like using CQI transmitted from each communication terminal apparatus, while performing scheduling. Then the base station apparatus modulates and encodes transmission data using such a selected modulation scheme, encoding rate and the like, and transmits the data to each communication terminal apparatus based on the scheduling result. By this means, a large volume of data can be transmitted at high speed from the base station apparatus to the communication terminal apparatus.
However, for conventional communication terminal apparatuses and base station apparatus, large volumes of data are transmitted at high speed from the base station apparatus to the communication terminal apparatuses using a system exclusively for the downlink like the HSDPA system, and when applying this system to the uplink as it is, the problem occurs that optimum scheduling according to data cannot be performed in the base station apparatus.
An object of the present invention is to perform optimum scheduling for the uplink according to data in each-mobile apparatus.
The object is achieved by configuring a communication terminal apparatus such that when transmission data is accumulated in a buffer, CQI is transmitted and when no transmission data is in the buffer, CQI is not transmitted. Further, when the amount of transmission data accumulated in the buffer is at or above a threshold value so that the transmission data is likely to overflow, or when a small amount of accumulated transmission data is left in the buffer so that the transmission thereof is desirably finished early, the communication terminal apparatus increases the number of transmit slots temporarily and the base station apparatus performs scheduling that preferentially assigns transmission to a communication terminal apparatus from which the number of CQI receive slots in a time unit of CQI transmit assignment has increased, thereby achieving the object. Yet further, when tolerable delay time of transmission data accumulated in the buffer is of a small amount, the communication terminal apparatus increases the number of transmit slots temporarily and the base station apparatus performs scheduling such that a communication terminal apparatus from which the number of CQI receive slots in a time unit of CQI transmit assignment has increased can transmit at high priority, thereby achieving the object.
Embodiments of the present invention will be described in detail below with reference to the drawings.
Mobile apparatus 100 comprises essentially an antenna 101, a receive radio section 102, a despreading section 103, a demodulator 104, a channel coding section 105, a buffer 106, a CQI generating section 107, a base station information extracting section 108, a channel coding section 109, a modulator 110, a spreading section 111, and a transmit radio section 112.
Base station apparatus 200 comprises essentially an antenna 201, a receive radio section 202, a despreading section 203, demodulators 204-1 to 204-n, channel coding sections 205-1 to 205-n, a CQI extracting section 206, a condition setting section 207, channel coding sections 209-1 to 209-n, modulators 210-1 to 210-n, spreading sections 211-1 to 211-n, and a transmit radio section 212.
First, the configuration of mobile apparatus 100 will be described using
Despreading section 103 performs despreading on the received signal inputted from receive radio section 102 using the same spreading code as has been used when spreading and outputs to the demodulator 104.
Demodulator 104 demodulates the received signal inputted from despreading section 103 and outputs to the channel coding section 105.
Channel coding section 105 decodes the received signal inputted from demodulator 104 to obtain received data for this mobile apparatus and outputs the decoded received data to the base station information extracting section 108.
Buffer 106 temporarily stores transmission data and outputs the stored transmission data to the channel coding section 109. Also, buffer 106 outputs a signal to the effect that transmission data has been stored to a CQI transmission control section 113.
When a control signal is inputted from the CQI transmission control section 113, CQI generating section 107 generates CQI based on quality information and outputs the generated CQI to the channel coding section 109. Note that the transmit power or the like of a control channel having its transmit power controlled is used as the quality information.
Base station information extracting section 108 extracts scheduling information and transmit parameter information from the received data inputted from channel coding section 105 and outputs to modulator 110 and channel coding section 109. Here, the transmit parameter information is information such as the modulation scheme and encoding rate used when mobile apparatus 100 generates transmission data, and is calculated by the base station apparatus 200 and then sent in. Also, the scheduling information is information indicating mobile apparatuses that are allowed to transmit and being set by the base station apparatus.
Channel coding section 109 encodes transmission data inputted from buffer 106 and CQI inputted from CQI generating section 107 based on the transmit parameter information and scheduling information inputted from base station information extracting section 108 and outputs to modulator 110. Note that the channel coding section 109 outputs transmission data only when transmission is allowed by scheduling and does not output transmission data when transmission is not allowed.
Modulator 110 modulates the transmission data inputted from channel coding section 109 according to the modulation scheme based on the transmit parameter information inputted from base station information extracting section 108, and outputs to the spreading section 111.
Spreading section 111 performs spreading on the transmission data inputted from modulator 110 using a spreading code and outputs to the transmit radio section 112.
Transmit radio section 112 performs processing such as up-conversion from a base band frequency to a radio frequency on the transmission data inputted from spreading section 111 and transmits via antenna 101.
When a signal to the effect that transmission data has been stored is inputted from buffer 106, CQI transmission control section 113 outputs a control signal to the effect that CQI is to be generated to the CQI generating section 107.
Next, the configuration of base station apparatus 200 will be described using
Despreading section 203 performs despreading on the receive signal inputted from receive radio section 202 using the same spreading codes as have been used when spreading and outputs to demodulators 204-1 to 204-n.
Demodulators 204-1 to 204-n demodulate the despread receive signals inputted from the despreading section 203 and outputs to the channel coding sections 205-1 to 205-n.
Channel coding sections 205-1 to 205-n decode the receive signals inputted from demodulators 204-1 to 204-n to obtain received data from the respective mobile apparatuses and outputs the decoded received data to CQI extracting section 206.
CQI extracting section 206 extracts CQI transmitted from each mobile apparatus from the received data inputted from channel coding sections 205-1 to 205-n, and outputs the extracted CQIs to the condition setting section 207.
Condition setting section 207 determines transmit parameters based on the CQIs inputted from CQI extracting section 206 while performing scheduling, and outputs the transmit parameter information and the scheduling information to the channel coding sections 209-1 to 209-n.
Channel coding sections 209-1 to 209-n encode the transmit parameter information and scheduling information inputted from condition setting section 207 and outputs to modulators 210-1 to 210-n. At this time, channel coding section 209-1 to 209-n encodes and outputs transmit parameter information to be transmitted to a mobile apparatus as an object to transmit to in scheduling, or when transmitting on a common control channel, which all the mobile apparatuses receive, encodes and outputs as transmit parameter information for the specific channel. Note that transmission data inputted into channel coding section 209-1 to 209-n is encoded separately from the transmit parameter information and scheduling information.
Modulator 210-1 to 210-n modulates the transmission data inputted from channel coding section 209-1 to 209-n and outputs to the spreading section 211-1 to 211-n.
Spreading section 211-1 to 211-n performs spreading on the transmission data inputted from the modulator 210-1 to 210-n using a spreading code and outputs to the transmit radio section 212.
Transmit radio section 212 performs processing such as up-conversion from a base band frequency to a radio frequency on the transmission data inputted from spreading section 211-1 to 211-n and transmits via antenna 201.
Next, the operation of mobile apparatus 100 will be explained using the flow chart of
As described above, according to the communication terminal apparatus and the base station apparatus of the present embodiment, when transmission data is accumulated in the buffer, CQI is transmitted and when transmission data is not accumulated in the buffer, CQI is not transmitted. Thus, when the mobile apparatus has data to be transmitted, the base station apparatus performs scheduling based on the CQI. Hence, for the uplink, optimum scheduling can be performed according to data in each mobile station. Furthermore, because CQI is transmitted only when data to be transmitted exists, power consumption can be reduced.
Although in the present embodiment, CQI is transmitted regardless of the cumulative amount when transmission data is accumulated in the buffer, not being limited to the case where CQI is always transmitted when transmission data is accumulated in the buffer, it may be so configured that CQI is transmitted when the cumulative amount of transmission data accumulated in the buffer becomes equal to or greater than a threshold value.
CQI transmission control section 113 of mobile apparatus 100 compares the cumulative amount of transmission data accumulated in buffer 106 with a threshold value, which amount is input from the buffer, and when the cumulative amount is at or above the threshold value, outputs a control signal for increasing the number of slots in a time unit of CQI transmit assignment over a usual number of CQI transmit slots to CQI generating section 107. Moreover, CQI transmission control section 113 receives from buffer 106 a value related to the transmission data other than the cumulative amount of data in buffer 106 and controls to transmit CQIs in a transmit pattern of transmit slots according to the value. Only the transmit pattern of transmit slots is changed without changing the number of CQI transmit slots in a time unit of CQI transmit assignment. Here, the value related to data is a value based on some information about data such as the type of data, e.g., voice data and image data, QoS (Quality of Service), and the number of retransmission times. The method for increasing and decreasing the time unit of CQI transmit assignment and the number of CQI transmit slots in a time unit of CQI transmit assignment will be described later.
CQI generating section 107 generates CQI based on the control signal inputted from CQI transmission control section 113 and quality information, and outputs to channel coding section 109. Furthermore, CQI generating section 107 generates CQIs in a transmit pattern of transmit slots according to priority based on the control signal inputted from CQI transmission control section 113.
Next, the configuration of base station apparatus 400 will be described using
Condition setting section 402 performs scheduling based on CQIs inputted from CQI extracting section 206, and the segment information and receive pattern of CQI receive slots in a time unit of CQI transmit assignment inputted from report timing observing section 401, determines transmit parameters, and outputs the scheduling information and the transmit parameter information to channel coding sections 209-1 to 209-n.
Next, the configuration of condition setting section 402 will be described using
Scheduler 501 determines a mobile apparatus to which transmission data is to be transmitted based on CQIs inputted from CQI extracting section 206, and the segment information and receive timing information inputted from report timing observing section 401, and the transmit parameter information inputted from transmit parameter setting section 502, and outputs scheduling information indicating a mobile station to which transmission is allowed to channel coding sections 209-1 to 209-n. Scheduler 501 determines that a mobile apparatus 100 from which the number of CQI receive slots in a time unit of CQI transmit assignment is large has transmission data that it wants to transmit early, and performs scheduling such that the mobile apparatus 100 having transmission data that it wants to transmit early can transmit at higher priority than the other mobile apparatuses 100.
Transmit parameter setting section 502 determines the modulation scheme and encoding rate based on CQI inputted from CQI extracting section 206 and outputs the determined modulation scheme and encoding rate as transmit parameter information to channel coding section 209-1 to 209-n. Note that the transmit parameters are not limited to an encoding rate and a modulation scheme but may be other parameters such as the number of multiple codes.
Next, the method of changing the time unit of CQI transmit assignment and the number of CQI transmit slots in a time unit of CQI transmit assignment will be explained using
A first method of changing the number of CQI transmit slots is to repeat two consecutive CQI transmission slots and two consecutive CQI non-transmission slots such as the first slot, second slot, fifth slot, sixth slot, etc., as shown by oblique hatching in
A second method of changing the number of CQI transmit slots is to transmit a CQI in every other slot such as the first slot, third slot, fifth slot, seventh slot, etc., as shown by oblique hatching in
Here, in FIGS. 6(b) and 6(c), the numbers of CQI transmit slots in a time unit of CQI transmit assignment are the same, but the patterns of CQI transmit slots in a time unit of CQI transmit assignment are different. By the mobile apparatus changing the transmission pattern according to the priority information of transmission data as described above, the base station apparatus can perform scheduling taking the transmission pattern into account.
Next, the operation of mobile apparatus 100 will be explained using
Next, the operation of mobile apparatus 100 when scheduling is performed such that transmission data accumulated in buffer 106 does not overflow will be explained using
Next, the configuration of base station apparatus 400 will be described using
As described above, according to the communication terminal apparatus and the base station apparatus of the present embodiment, the mobile apparatus changes the number of CQI transmit slots in a time unit of CQI transmit assignment according to the transmission data amount, and the base station apparatus, by measuring the number of incoming CQI slots in a time unit of CQI transmit assignment, can estimate the amount of to-be-transmitted data in the mobile apparatus, and the estimating result can be taken into account in scheduling. Thus, optimum scheduling can be performed for the uplink according to the data amount in each mobile apparatus. Furthermore, data can be transmitted on the uplink efficiently using resources. Moreover, because the transmit pattern of CQI transmit slots in a time unit of CQI transmit assignment is changed according to the value related to data transmission, more elaborate scheduling can be performed, and because the number of CQI transmission times need not be reduced, the base station apparatus can receive an enough number of CQIs when scheduling. Thus, communication of high speed and large capacity can be performed according to the propagation path state.
Note that although in the present embodiment information about transmission data is indirectly informed by using the number of transmit slots and the transmit pattern, only one of the number of transmit slots and the transmit pattern may be used.
First, the configuration of mobile apparatus 1000 will be explained using
Tolerable delay time information generating section 1001 determines the tolerable delay time based on data accumulated in buffer 106, and outputs the determined tolerable delay time as tolerable delay time information to CQI transmission control section 113. Here, the tolerable delay time is a time in which the data is to be transmitted or remaining time until the time when the data desirably has been transmitted.
When the type of data to be transmitted is the data type such as voice whose communication contents cannot be communicated to the receiving partner if the receiving side receives them delayed during communication, the tolerable delay time is short.
Next, the operation of mobile apparatus 1000 will be explained using
CQI transmission control section 113 outputs to CQI generating section 107 a control signal for generating CQIs in a transmit pattern of CQI transmit slots in a time unit of CQI transmit assignment according to the value related to transmission data. CQI generating section 107 generates CQIs based on the control signal from CQI transmission control section 113. Next, CQI generating section 107 outputs the generated CQI to channel coding section 109; channel coding section 109 encodes the generated CQI; modulator 110 adaptively modulates; spreading section 111 performs spreading; and transmit radio section 112 performs processing such as up-conversion from a base band frequency to a radio frequency and transmits the CQI via antenna 101 (ST1104). Note that because the operation of the base station apparatus is the same as that of base station apparatus 200 in the above embodiment 2, a description thereof is omitted.
As described above, according to the communication terminal apparatus and the base station apparatus of the present embodiment, the mobile apparatus changes the number of CQI transmit slots in a time unit of CQI transmit assignment based on the tolerable delay time, and the base station apparatus, by measuring the number of incoming CQI slots in a time unit of CQI transmit assignment, can estimate the tolerable delay time for data in the mobile apparatus, and the estimating result can be taken into account in scheduling. Thus, optimum scheduling can be performed for the uplink according to the data in each mobile apparatus. Furthermore, data can be transmitted on the uplink efficiently using resources. Moreover, because the transmit pattern of CQI transmit slots in a time unit of CQI transmit assignment is changed according to the value related to data transmission, more elaborate scheduling can be performed, and because the number of CQI transmission times need not be reduced, the base station apparatus can receive an enough number of CQIs when scheduling. Thus, communication of high speed and large capacity can be performed according to the propagation path condition.
Note that although in the present embodiment information about transmission data is indirectly informed by using the number of transmit slots and the transmit pattern, only one of the number of transmit slots and the transmit pattern may be used.
First, the configuration of mobile apparatus 1200 will be described using
Report timing control signal extracting section 1201 extracts segment information included therein from the received data inputted from the channel coding section 105 and outputs to the report timing control instructing section 1202.
Report timing control instructing section 1202 determines a threshold value with which CQI transmission control section 1203 compares the amount of transmission data accumulated in buffer 106, based on the segment information inputted from report timing control signal extracting section 1201, and outputs the determined threshold value information to CQI transmission control section 1203.
Next, the configuration of base station apparatus 1300 will be described using
Report timing observing section 1301 classifies the numbers of receive slots according to the number of receive slots in a time unit of CQI transmit assignment, determines which segment each mobile apparatus 1200 belongs to, and outputs the segment to which each mobile apparatus 1200 belongs to the report timing control signal generating section 1303. Furthermore, report timing observing section 1301 can change the threshold value for each segment under the control of report timing control signal generating section 1303. Yet further, report timing observing section 1301 outputs the receive pattern of CQI receive slots in a time unit of CQI transmit assignment to condition setting section 1302.
Condition setting section 1302 determines transmit parameters by using the CQIs inputted from CQI extracting section 206, and the numbers of CQI receive slots in a time unit of CQI transmit assignment and receive patterns of CQI receive slots in a time unit of CQI transmit assignment inputted from report timing observing section 1301, while performing scheduling, and outputs to the channel coding sections 209-1 to 209-n.
Report timing control signal generating section 1303 outputs information indicating the number of times to report CQI and segments for which timing is to be changed to the channel coding section 209-1 to 209-n. Also, at the same time, report timing control signal generating section 1303 outputs to report timing observing section 1301 a signal to change the threshold value for each segment. For example, when mobile apparatuses 1200 are concentrated in a same segment, report timing control signal generating section 1303 can determine a mobile apparatus 1200 that is to be preferentially scheduled by controlling to divide the concentrated segment further.
Channel coding section 209-1 to 209-n encodes the transmit parameter information and scheduling information inputted from condition setting section 1302 and the segment information inputted from report timing control signal generating section 1303, and outputs to modulator 210-1 to 210-n. At this time, channel coding section 209-1 to 209-n encodes and outputs the transmit parameter information to be transmitted to a mobile apparatus as an object to transmit to in scheduling, or when transmitting on a common control channel, which all the mobile apparatuses receive, encodes and outputs as transmit parameter information for the specific channel. Note that because the operation of mobile apparatus 1200 is the same as that of the above embodiment 2 shown in
Next, the configuration of CQI transmission control section 1203 will be described using
Threshold value setting section 1401 sets a threshold value for each segment according to an instruction signal for setting a threshold value inputted from report timing control instructing section 1202. When the instruction signal is an instruction signal to the effect that the threshold value is to be changed, the threshold value is changed, and when the instruction signal is an instruction signal to the effect that the threshold value is to be unchanged, the threshold value is not changed. The threshold value for each segment is set by threshold value setting section 1401 to become the same as the threshold value for the segment in report timing observing section 1301. Then, threshold value setting section 1401 outputs the set threshold values to CQI transmit timing setting section 1402.
CQI transmit timing setting section 1402 compares the threshold values inputted from threshold value setting section 1401 and the cumulative amount of transmission data inputted from buffer 106, and outputs a control signal for transmitting in CQI transmit slots for the segment to which the cumulative amount of transmission data belongs to CQI generating section 107. Furthermore, CQI transmit timing setting section 1402 outputs an instruction signal for generating CQIs to CQI generating section 107 based on information related to the transmission of data inputted from buffer 106.
Next, the configuration of report timing control signal generating section 1303 will be described using
Distribution determining section 1501 determines whether a segment in which mobile apparatuses 1200 are concentrated exists and whether a mobile apparatus 1200 that belongs to a segment of high priority exists, based on the segment to which the number of CQI receive slots in a time unit of CQI transmit assignment from each mobile apparatus 1200, inputted from report timing observing section 1301, belongs. Then, distribution determining section 1501 outputs the determining results to the change deciding section 1502.
Change deciding section 1502 outputs segment information decided based on the determining results inputted from distribution determining section 1501 to channel coding sections 209-1 to 209-n. Specifically, in the case of no change to the threshold value for each segment, the change deciding section 1502 outputs the segment information as it is, without a change to the threshold value for each segment to channel coding sections 209-1 to 209-n, or does not send a signal. On the other hand, when mobile apparatuses 1200 are concentrated in a same segment, the change deciding section 1502 decides to set threshold values for dividing the concentrated segment further. Moreover, when no mobile apparatus 1200 exists in the segment of the largest number of receive slots in a time unit of CQI transmit assignment, in order to determine a mobile apparatus 1200 that is to be preferentially scheduled, it is decided to change the threshold values for all segments. When it is decided to change the threshold values for the segments, a signal for changing the segments and distribution information of the mobile apparatuses 1200 are output to the segment change section 1503.
When receiving a signal to the effect that the change of the segments is decided, the segment change section 1503 changes the threshold values for the segments based on the distribution information inputted from the change deciding section 1502 and outputs information about the changed threshold value for each segment to report timing observing section 1301.
Next, the transmitting and receiving of CQI and a transmit timing control signal in mobile apparatus 1200 and base station apparatus 1300 will be explained using
As described above, according to the communication terminal apparatus and the base station apparatus of the present embodiment, in addition to the effect of the above embodiment 2, the threshold value with which the amount of transmission data accumulated in the buffer is compared is set based on the segment information transmitted from the base station apparatus. Hence, even when the amount of transmission data accumulated in the buffer is about the same as in other mobile apparatuses, preferential scheduling can be performed among those mobile apparatuses, and elaborate scheduling can be performed according to the data amount.
Note that although in the present embodiment information about transmission data is indirectly informed by using the number of transmit slots and the transmit pattern, only one of the number of transmit slots and the transmit pattern may be used.
First, the configuration of mobile apparatus 1700 will be described using
Report timing control signal extracting section 1701 extracts segment information included therein from the received data inputted from the channel coding section 105 and outputs to the report timing control instructing section 1702.
Report timing control instructing section 1702 determines a threshold value which is compared with the tolerable delay time output from tolerable delay time information generating section 1703, based on the segment information inputted from report timing control signal extracting section 1701, and outputs the determined threshold value as threshold information to CQI generating section 107.
Tolerable delay time information generating section 1703 obtains remaining tolerable delay time from the tolerable delay time decided according to the type of data inputted from buffer 106 and a current delay, and outputs as tolerable delay time information to CQI transmission control section 1704.
Next, the configuration of base station apparatus 1800 will be described using
Report timing control signal generating section 1803 outputs information indicating the number of times to report CQI and segments for which timing is to be changed to the channel coding section 209-1 to 209-n. Also, at the same time, report timing control signal generating section 1803 outputs to report timing observing section 1801 a signal to change the threshold value for each segment. For example, when mobile apparatuses 1700 are concentrated in a same segment, the report timing control signal generating section 1803 can determine a mobile apparatus 1700 that is to be preferentially scheduled by controlling to divide the concentrated segment further.
Channel coding section 209-1 to 209-n encodes transmit parameter information and scheduling information inputted from condition setting section 207 and the segment information inputted from report timing control signal generating section 1803, and outputs to modulator 210-1 to 210-n. At this time, channel coding section 209-1 to 209-n encodes and outputs the transmit parameter information to be transmitted to a mobile apparatus as an object to transmit to in scheduling, or when transmitting on a common control channel, which all the mobile apparatuses receive, encodes and outputs as transmit parameter information for the specific channel.
As described above, according to the communication terminal apparatus and the base station apparatus of the present embodiment, in addition to the effect of the above embodiment 3, the threshold value with which the tolerable delay time is compared is set based on the segment information transmitted from the base station apparatus. Hence, even when the tolerable delay time of transmission data accumulated in the buffer is about as short as the tolerable delay times of transmission data in other mobile apparatuses, preferential scheduling can be performed among those mobile apparatuses, and elaborate scheduling can be performed according to the data type.
Note that although in the present embodiment information about transmission data is indirectly informed by using the number of transmit slots and the transmit pattern, only one of the number of transmit slots and the transmit pattern may be used.
In the above embodiments 1 to 5, CQI transmitted to the base station apparatus on the uplink can be any information indicating the communication quality of the mobile apparatus such as power value information of transmit power, information about remaining transmit power, i.e., the difference between tolerable maximum transmit power (upper limit value) of the mobile apparatus and transmit power of the individual channel, or information about the ratio of the remaining transmit power to the transmit power of the individual channel. Moreover, the above embodiments 1 to 5 can be used in combination.
As described above, according to the present invention, optimum scheduling can be performed for the uplink according to the data in each mobile station.
The present description is based on Japanese Patent Application No. 2002-295449 filed on Oct. 8, 2002, which is herein incorporated by reference.
The present invention relates to a communication terminal apparatus and a base station apparatus, and is particularly suitable to be applied to a communication terminal apparatus and a base station apparatus in a system that performs high speed packet transmission on the uplink, wherein scheduling is performed by the base station apparatus based on CQI transmitted from the communication terminal apparatus.
Number | Date | Country | Kind |
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2002-295449 | Oct 2002 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP03/10333 | 8/14/2003 | WO |