JP2003347980A - Mobile station, wireless base station, wireless communication control method, and fading frequency estimation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the degradation of communication quality. <P>SOLUTION: A mobile station 10 of this invention includes a switching timing discrimination section 12 and a transmission processing section 13. The switching timing discrimination section 12 measures a wireless quality index value for each downlink time slot and discriminates the switching timing of transmission diversity on the basis of the wireless quality index value. The transmission processing section 13 controls transmission of the discrimination result of the switching timing by the switching timing discrimination section 12 to a wireless base station by using an uplink. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mobile station, a radio base station, a radio communication control method, and a fading frequency estimation method.

[0002]

2. Description of the Related Art Generally, in radio communication, a phenomenon in which the reception level of a radio wave fluctuates with the movement of a mobile station or the passage of time due to interference of a reflected wave (hereinafter referred to as "fading").
It is written. ) Occurs. Fading is a factor in deteriorating communication quality, that is, bit error rate characteristics. For this reason, in the CDMA (Code Division Multiple Access) system, the TDMA (Time Division Multiple Access) system, and the TDD (Time Division Duplex) system, transmission diversity for compensating for deterioration of communication quality due to fading has been put to practical use.

[0003]

However, in the above prior art, a time slot (uplink time slot) for estimating the state of a wireless communication channel and a time slot (downlink) for actually transmitting data by performing transmission diversity are used. In the case where the time difference between the time slot and the link time slot is large, there is a problem that the accuracy of the transmission diversity is reduced. Such a decrease in the accuracy of the transmission diversity is particularly remarkable when a change in the wireless communication environment such as a change in the fading frequency at each time is large.

[0004] The present invention has been made in view of the above problems, and has as its object to provide a mobile station, a radio base station, a radio communication control method, and a fading frequency estimating method with reduced degradation of communication quality. I do.

[0005]

In order to solve the above-mentioned problems, a mobile station according to the present invention measures a radio quality index value for each downlink time slot, and performs transmission diversity based on the radio quality index value. And a transmitting means for transmitting the result of the determination of the switching timing by the determining means to the radio base station using uplink.

A radio base station according to the present invention is a radio base station that communicates with the above-mentioned mobile station, and is a channel estimating means for estimating a channel for an uplink time slot. A determination result receiving means for receiving the determination result of the switching timing; a channel estimation result by the channel estimation means; and a downlink time slot based on the determination result of the switching timing received by the determination result receiving means. Using diversity control means (including control not performing transmission diversity) for each transmission diversity, and transmission diversity controlled by the diversity control means, to transmit data to the mobile station on the downlink time slot. And data transmission means for transmitting the data.

In the radio communication control method according to the present invention, the mobile station measures a radio quality index value for each downlink time slot, and determines a transmission diversity switching timing based on the radio quality index value. And the mobile station transmits a determination result of the switching timing in the determination step to a radio base station using an uplink, and the radio base station transmits a channel to an uplink time slot. A channel estimation step of performing estimation, the radio base station receiving a determination result of the switching timing transmitted from the mobile station in the determination result transmission step, a determination result receiving step, Based on the estimation result and the determination result of the switching timing received in the determination result receiving step A diversity control step of controlling transmission diversity for each downlink time slot, and data for transmitting data to the mobile station on the downlink time slot using transmission diversity controlled by the diversity control step. Transmitting step.

According to these inventions, the transmission diversity switching timing is determined by the radio quality index value (eg, SIR: Signal to Interference power) measured by the mobile station.
er Ratio), and the result of this determination is fed back to the radio base station. As a result, transmission diversity is switched and controlled at a suitable timing different for each frame. That is, it is possible to dynamically control the switching timing of the transmission diversity according to the fading frequency (also referred to as the fading pitch). As a result, degradation of downlink communication quality can be reduced.

Preferably, in the mobile station according to the present invention,
The determining means determines the switching timing of the transmission diversity at a predetermined time interval and totals the determination result, and the transmitting means calculates the totaling result of the switching timing by the determining means using the uplink to the radio base station. Send to the station.

The radio base station according to the present invention is preferably a radio base station which communicates with the mobile station described above,
The determination result receiving means receives the aggregation result of the switching timing transmitted by the transmission means of the mobile station, the diversity control means, the channel estimation result,
Transmission diversity is controlled for each downlink time slot based on the switching timing tally received by the determination result receiving means.

Preferably, in the radio communication control method according to the present invention, in the determining step, the mobile station determines a transmission diversity switching timing at a predetermined time interval, sums up the determination results, and transmits the determination result transmission. In the step, the mobile station transmits an aggregation result of the switching timing in the determination step to the wireless base station using an uplink, and in the determination result receiving step, the wireless base station performs the determination result transmitting step Received from the mobile station the aggregation result of the switching timing transmitted in, in the diversity control step,
The radio base station controls transmission diversity for each downlink time slot based on the channel estimation result and the aggregation result of the switching timing received in the determination result receiving step.

According to these inventions, the determination results of the switching timing of the transmission diversity are summed up (including not only the sum total but also the averaging) at predetermined time intervals (for example, 100 ms for 10 frames), It is fed back to the radio base station. In addition, the determination result is more accurate in which the influence of the sudden change in the communication environment on the switching timing determination result is eliminated as much as possible. As a result, transmission diversity is switched and controlled at a suitable timing different for each frame. As a result, it is possible to reduce degradation of downlink communication quality.

[0013] In the radio base station according to the present invention, more preferably, the diversity control means transmits, for each downlink time slot, based on the channel estimation result and the switching timing determination result or the aggregation result. Decide if you need diversity.

In the radio communication control method according to the present invention,
More preferably, in the diversity control step,
The radio base station determines whether or not transmission diversity is required for each downlink time slot based on the channel estimation result and the switching timing determination result or aggregation result.

According to these inventions, it is determined whether or not the radio base station uses transmission diversity, that is, whether or not transmission diversity itself is necessary (ON / OFF). For example, when it is predicted that desired communication quality cannot be obtained despite execution of transmission diversity, or when the channel estimation result is sufficiently good to secure a predetermined communication quality, the radio base station If transmission diversity is not performed, the processing load associated with transmission diversity control can be reduced.

[0016] In the radio base station according to the present invention, more preferably, the diversity control means transmits, for each downlink time slot, based on the channel estimation result and the switching timing determination result or aggregation result. Determine the type of diversity.

In the wireless communication control method according to the present invention,
More preferably, in the diversity control step,
The radio base station determines a type of transmission diversity for each downlink time slot based on the channel estimation result and the switching timing determination result or the aggregation result.

According to these inventions, the type of transmission diversity used by the radio base station (for example, STD: Select
ive Transmit Diversity, TxAA: Transmit Adaptiv
e Antennas, TSTD: Time Switched Transmit Diver
sity) is determined by the radio base station. Therefore, as compared with the case where transmission diversity is controlled by ON / OFF of the transmission diversity, it is possible to realize more detailed transmission diversity according to the fading frequency.

[0019] In the radio base station according to the present invention, more preferably, the diversity control means uses an antenna used for data transmission in STD based on the channel estimation result and the switching timing determination result or aggregation result. Is determined for each downlink time slot.

In the wireless communication control method according to the present invention,
More preferably, in the diversity control step,
An antenna to be used for data transmission in the STD is determined for each downlink time slot based on the channel estimation result and the switching timing determination result or the aggregation result.

According to these inventions, the antenna used for data transmission in the STD is selectively provided for each downlink time slot based on the channel estimation result and the switching timing determination result or aggregation result. Is determined. Thus, data is transmitted from the radio base station to the mobile station using an antenna that is expected to have a higher transmit diversity effect. As a result, it is possible to further reduce deterioration in downlink communication quality.

[0022] The mobile station according to the present invention comprises: measuring means for measuring a radio quality index value for each downlink time slot;
Transmitting means for transmitting the wireless quality index value measured by the measuring means to a wireless base station using uplink.

A radio base station according to the present invention is a radio base station that communicates with the above-mentioned mobile station, and is a channel estimating means for estimating a channel for an uplink time slot, and a radio signal transmitted from the mobile station. An index value receiving unit that receives the radio quality index value, a channel estimation result by the channel estimating unit, and the radio quality index value received by the index value receiving unit. Diversity control means for controlling transmission diversity; and data transmission means for transmitting data to the mobile station on the downlink time slot using transmission diversity controlled by the diversity control means.

[0024] In the radio communication control method according to the present invention, the mobile station measures a radio quality index value for each downlink time slot, and the mobile station determines the radio quality index value measured in the measurement step. An index value transmitting step of transmitting a quality index value to the radio base station using the uplink, the radio base station performs a channel estimation for an uplink time slot, and the radio base station includes: An index value receiving step of receiving the radio quality index value transmitted from the mobile station in the index value transmitting step, the radio base station performs a channel estimation result in the channel estimation step, and the index value receiving step. Based on the received wireless quality index value, and controlling transmission diversity for each downlink time slot. And control step, the radio base station,
A data transmission step of transmitting data to the mobile station on the downlink time slot using transmission diversity controlled in the diversity control step.

According to these inventions, the measurement result of the radio quality index value (for example, SIR) for each downlink time slot is transmitted from the mobile station to the radio base station. The radio base station can switch the transmission diversity at a different suitable timing for each frame by referring to the measurement result. That is, it is possible to perform variable control of the transmission diversity switching timing that matches the fading frequency. As a result, degradation of downlink communication quality can be reduced.

Preferably, in the radio base station according to the present invention, the index value receiving means receives a radio quality index value at a predetermined time interval transmitted by the transmitting means of the mobile station, and the diversity control means Transmission diversity is controlled for each downlink time slot based on the channel estimation result and the aggregation result of the radio quality index values received by the index value receiving unit.

Preferably, in the radio communication control method according to the present invention, in the index value receiving step, the radio base station receives a radio quality index value at a predetermined time interval transmitted from the mobile station, and In the control step, the radio base station controls transmission diversity for each downlink time slot based on the channel estimation result and the aggregation result of the radio quality index values received in the index value receiving step. I do.

According to these inventions, the radio quality index value is calculated at a predetermined time interval (for example, 100 frames for 10 frames).
ms), is used for controlling the transmission diversity by the radio base station after being summed up (including not only the summation but also the averaging). By this means, the radio base station can control transmission diversity with higher accuracy by minimizing the effects of fluctuations in switching timing between frames and the effects of sudden changes in the communication environment on radio quality index values. it can.

[0029] In the radio base station according to the present invention, more preferably, said diversity control means is configured to transmit a downlink signal based on said channel estimation result and said radio quality index value or a totaling result of said radio quality index value. The necessity of transmission diversity is determined for each time slot.

In the wireless communication control method according to the present invention,
More preferably, in the diversity control step,
The radio base station determines whether or not transmission diversity is necessary for each downlink time slot based on the channel estimation result and the radio quality index value or the totalization result of the radio quality index values.

According to these inventions, whether or not the radio base station uses transmission diversity, that is, whether or not transmission diversity itself is necessary (ON / OFF) is determined. For example, when it is predicted that desired communication quality cannot be obtained despite execution of transmission diversity, or when the channel estimation result is sufficiently good to secure a predetermined communication quality, the radio base station It is not necessary to perform transmission diversity, and the processing load associated with transmission diversity control can be reduced.

[0032] In the radio base station according to the present invention, more preferably, the diversity control means is configured to transmit a downlink signal based on the channel estimation result and the radio quality index value or the totalization result of the radio quality index value. The type of transmission diversity is determined for each time slot.

In the radio communication control method according to the present invention,
More preferably, in the diversity control step,
The radio base station determines the type of transmission diversity for each downlink time slot based on the channel estimation result and the radio quality index value or the aggregation result of the radio quality index values.

According to these inventions, the type of transmission diversity used by the radio base station (for example, STD, TxA
A, TSTD) is determined. Therefore, as compared with the case where transmission diversity is controlled by ON / OFF of the transmission diversity, it is possible to realize more detailed transmission diversity according to the fading frequency.

[0035] In the radio base station according to the present invention, more preferably, said diversity control means performs a data transmission in STD based on said channel estimation result and said radio quality index value or a total result of said radio quality index value. An antenna used for transmission is determined for each downlink time slot.

In the radio communication control method according to the present invention,
More preferably, in the diversity control step,
The radio base station determines an antenna to be used for data transmission in the STD for each downlink time slot based on the channel estimation result and the radio quality index value or the aggregation result of the radio quality index values.

According to these inventions, the antenna used for data transmission in the STD determines the downlink time based on the channel estimation result and the radio quality index value or the aggregation result of the radio quality index value. It is selectively determined for each slot. Thus, data is transmitted from the radio base station to the mobile station using an antenna that is expected to have a higher transmit diversity effect. As a result, it is possible to further reduce deterioration in downlink communication quality.

[0038] A mobile station according to the present invention comprises: a frame selecting means for selecting a frame to be used for determining the switching timing of transmission diversity; and a mobile station for each downlink time slot included in the frame selected by the frame selecting means. A radio quality index value is measured, and a determination unit that determines a transmission diversity switching timing based on the radio quality index value, and a determination result of the switching timing by the determination unit is transmitted to a radio base station using an uplink. Transmission means.

[0039] A radio base station according to the present invention comprises: diversity control means for controlling transmission diversity for each downlink time slot included in a frame used when determining transmission diversity switching timing; and control by the diversity control means. Data transmission means for transmitting data to the mobile station on the downlink time slot, using channel diversity, channel estimation means for performing channel estimation for the uplink time slot, And a decision result receiving means for receiving a transmitted decision result of the switching timing in the frame, wherein the diversity control means comprises: a channel estimation result by the channel estimating means; and the switching received by the decision result receiving means. Based on the timing judgment result, The transmission diversity is controlled for each downlink time slot included in a frame other than the above-described frame, and the data transmission unit is controlled by the diversity control unit for each downlink time slot included in a frame other than the frame. Transmit data to the mobile station on the downlink time slot using transmit diversity.

In the radio communication control method according to the present invention, the mobile station selects a frame to be used when determining the transmission diversity switching timing, and the mobile station is selected in the frame selection step. Measuring the radio quality index value for each downlink time slot included in the frame, and determining the switching timing of the transmission diversity based on the radio quality index value, the mobile station, the mobile station, the determination step A transmitting step of transmitting the determination result of the switching timing to the radio base station using the uplink, and a first diversity control step of the radio base station controlling transmission diversity for each downlink time slot included in the frame. And the first base station performs the first diversity control step. A first data transmission step of transmitting data to the mobile station on the downlink time slot using transmission diversity controlled by the radio base station, wherein the radio base station performs channel estimation on the uplink time slot. Performing a channel estimation step, wherein the wireless base station receives a determination result of switching timing in the frame transmitted from the mobile station, and the wireless base station performs channel estimation in the channel estimation step. A second diversity control step of controlling transmission diversity for each downlink time slot included in a frame other than the frame based on the result and the determination result of the switching timing received in the determination result receiving step. The radio base station communicates with the second diversity control step. A second data transmission step of transmitting data to the mobile station on the downlink time slot using transmission diversity controlled for each downlink time slot included in a frame other than the frame, including.

According to these inventions, only for the selected frame, the process of measuring the radio quality index value for each downlink time slot and the process of determining the timing of switching the transmission diversity are executed. By determining the transmission diversity switching timing only for a specific frame, the switching timing determination interval becomes longer,
Since it is rare that the fading frequency fluctuates rapidly, it is unlikely that the determination accuracy will be extremely reduced. Therefore, the processing load on the mobile station and the radio resources between the mobile station and the radio base station are reduced as compared with the case where the switching timing is determined for all the frames while maintaining the predetermined determination accuracy.

Preferably, in the radio base station according to the present invention, the diversity control means determines whether or not transmission diversity is required for each of the downlink time slots based on the channel estimation result and the switching timing determination result. To determine.

Preferably, in the wireless communication control method according to the present invention, in the second diversity control step,
The radio base station determines whether transmission diversity is required for each downlink time slot based on the channel estimation result and the switching timing determination result.

According to these inventions, whether or not the radio base station uses transmission diversity, that is, whether or not transmission diversity itself is necessary (ON / OFF) is determined. For example, if it is predicted that desired communication quality cannot be obtained despite execution of transmission diversity, or if the channel estimation result is sufficiently good to ensure a predetermined communication quality, the radio base station A station need not necessarily perform transmit diversity. As a result, the processing load associated with transmission diversity control can be reduced.

[0045] In the radio base station according to the present invention, more preferably, the diversity control means determines the transmission diversity for each downlink time slot based on the channel estimation result and the switching timing determination result. Determine the type.

In the radio communication control method according to the present invention,
More preferably, in the second diversity control step, the radio base station determines a type of transmission diversity for each of the downlink time slots based on the channel estimation result and the switching timing determination result. I do.

According to these inventions, the type of transmission diversity used by the radio base station (eg, STD, TxA
A, TSTD) is determined. Therefore, as compared with the case where transmission diversity is controlled by ON / OFF of the transmission diversity, it is possible to realize more detailed transmission diversity according to the fading frequency.

[0048] In the radio base station according to the present invention, more preferably, said diversity control means downlinks an antenna used for data transmission in STD based on said channel estimation result and said switching timing determination result. Is determined for each time slot.

In the radio communication control method according to the present invention,
More preferably, in the second diversity control step, the radio base station sets an antenna used for data transmission in STD to a downlink time slot based on the channel estimation result and the switching timing determination result. Determined every time.

According to these inventions, an antenna used for data transmission in STD is selectively determined for each downlink time slot based on the channel estimation result and the switching timing determination result. You. Thus, data is transmitted from the radio base station to the mobile station using an antenna that is expected to have a higher transmit diversity effect. As a result, it is possible to further reduce deterioration in downlink communication quality.

The mobile station according to the present invention comprises: a frame selecting means for selecting a frame to be used for determining the switching timing of transmission diversity; and a mobile station for each downlink time slot included in the frame selected by the frame selecting means. The wireless communication device includes a measuring unit that measures a wireless quality index value, and a transmitting unit that transmits the wireless quality index value measured by the measuring unit to a wireless base station using an uplink.

The radio base station according to the present invention comprises: diversity control means for controlling transmission diversity for each downlink time slot included in a frame used when determining transmission diversity switching timing; and control by the diversity control means. Data transmission means for transmitting data to the mobile station on the downlink time slot, using channel diversity, channel estimation means for performing channel estimation for the uplink time slot, Transmitted, an index value receiving means for receiving a radio quality index value in the frame, the diversity control means, the channel estimation result by the channel estimating means, the radio quality received by the index value receiving means Based on the index value, frames other than the frame The transmission diversity is controlled for each downlink time slot included in the data transmission means, the data transmission means uses transmission diversity controlled for each downlink time slot included in a frame other than the frame by the diversity control means. And transmitting data to the mobile station on the downlink time slot.

In the radio communication control method according to the present invention, a mobile station selects a frame to be used when determining transmission diversity switching timing, and the mobile station is selected in the frame selection step. A measuring step of measuring a radio quality index value for each downlink time slot included in the frame, and the mobile station transmits the radio quality index value measured in the measuring step to a radio base station using an uplink. A first diversity control step in which the radio base station controls transmission diversity for each downlink time slot included in the frame; and wherein the radio base station performs the first diversity control. Using the transmission diversity controlled in the step, on the downlink time slot A first data transmission step of transmitting data to a mobile station, a channel estimation step in which the radio base station performs channel estimation on an uplink time slot, and wherein the radio base station is transmitted from the mobile station. Further, an index value receiving step of receiving a radio quality index value in the frame, the radio base station, a channel estimation result in the channel estimation step, and the radio quality index value received in the index value receiving step A second diversity control step of controlling transmission diversity for each downlink time slot included in a frame other than the frame, and the radio base station executes the second diversity control step in the second diversity control step. Divers controlled for each downlink time slot included in a frame Use the switch,
Transmitting a data to the mobile station on the downlink time slot.

According to these inventions, the measurement result of the radio quality index value for each downlink time slot included in the selected frame is transmitted from the mobile station to the radio base station. The radio base station refers to the measurement result, and executes the transmission diversity switching timing determination process only for the selected frame. As a result, the processing load on the mobile station and the radio resources between the mobile station and the radio base station are reduced as compared with the case where the switching timing is determined for each frame for every frame. Since the switching timing of the transmission diversity is determined only for a specific frame, the interval for determining the switching timing becomes long, and there is a concern that the determination accuracy may be reduced. In this regard, it is rare that the fading frequency fluctuates abruptly, and it is unlikely that the determination accuracy will be extremely reduced.

According to the fading frequency estimating method of the present invention, the radio base station receives a decision result of receiving the switching timing of the transmission diversity, which is determined or totaled by the determination means of the mobile station; A frequency estimating step of estimating a fading frequency between the mobile station and the radio base station by referring to the switching timing received in the determination result receiving step. Further, according to the fading frequency estimation method according to the present invention, an index value receiving step in which a radio base station receives a radio quality index value from a mobile station, and the radio base station is received in the index value receiving step. A frequency estimating step of estimating a fading frequency between the mobile station and the radio base station with reference to the radio quality index value.

The transmission diversity switching timing determined by the determination means of the mobile station is the timing at which the accuracy of uplink channel estimation is predicted to decrease.
Further, the fading frequency is estimated based on a prediction result of a timing at which the accuracy of the uplink channel estimation decreases. The estimation of the fading frequency can be applied not only to the above-described determination of the switching timing but also to the control of the transmission power supplied to the channel, the adaptive modulation, and the like, whereby the application range of the present invention is widened.

[0057]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below in detail with reference to the accompanying drawings. First, the configuration will be described. FIG. 1 is a schematic diagram illustrating an overall configuration of a mobile communication system 100 according to the present embodiment. As shown in FIG. 1, the mobile communication system 100
The mobile station 10 includes a base station 20 and a mobile station 10 located in a cell C of the base station 20. The base station 20 and the mobile station 10
CDMA-TDD (Code Division Multiple Access-Ti
Two-way communication is performed via a wireless communication channel (hereinafter simply referred to as a “channel”) according to the “me Division Duplex” method.

FIG. 2 is a block diagram showing a functional configuration of the mobile station 10. As shown in FIG. As shown in FIG. 2, the mobile station 10 includes a downlink demodulation processing unit 11 and a switching timing determination unit 12
(Corresponds to judgment means, measurement means, and frame selection means)
And a transmission processing unit 13 (corresponding to a transmission unit). Hereinafter, each component will be described in detail.

The downlink demodulation processing section 11 has an antenna A
And the switching timing determination unit 12 by wire.
Demodulation processing is performed on data (hereinafter, referred to as “downlink data”) received by the antenna A via the channel.

The switching timing determination section 12 is connected to the downlink demodulation processing section 11 and the transmission processing section 13.
The switching timing determination unit 12 is a downlink demodulation processing unit 1
1 to the downlink (D
The wireless quality index value for each time slot for L (Down Link) is measured. The switching timing determination unit 12 determines the diversity switching timing based on the measured wireless quality index value, and outputs the determination result to the transmission processing unit 13.

Here, an example of the radio quality index value is a signal power to interference power ratio (SIR: Signal to Interference).
power Ratio), the ratio of the desired signal power to the interference signal power (CIR: Carrier to Interference power Rati)
o), Signal power to noise power ratio (SNR)
power Ratio), desired signal power to noise power ratio (CN
R: Carrier to Noise power Ratio) and received power.

The transmission processing unit 13 is connected to the switching timing judgment unit 12. The transmission processing unit 13 adds a switching timing determination result input from the switching timing determination unit 12 to data (hereinafter, referred to as “uplink data”) to be transmitted to the wireless base station 20 via the channel. I do. The transmission processing unit 13 performs a filtering process on the uplink data including the determination result as necessary, and transmits the uplink data to the radio base station 20 via the channel from the antenna A.

FIG. 3 is a block diagram showing a functional configuration of the radio base station 20. As shown in FIG. 3, the radio base station 20 includes an encoding unit 21, a spreading unit 22, a distribution unit 23, and a diversity control unit 24 (corresponding to a diversity control unit).
, A transmission processing unit 25 (corresponding to a data transmitting unit), and an uplink channel estimating unit 26 (corresponding to a channel estimating unit)
And an uplink demodulation processing unit 27 (corresponding to the determination result receiving means and the index value receiving means). Hereinafter, each component will be described in detail.

The encoding unit 21 is connected to the spreading unit 22 and performs well-known and customary encoding and interleaving processing on the data transmitted from the mobile station 10 via the channel, and spreads the data. 22.

The spreading section 22 includes an encoding section 21 and a distribution section 23.
, And performs spreading and scrambling on data input from the encoding unit 21, and outputs the data to the distribution unit 23.

The distribution unit 23 is connected to the spreading unit 22 and the diversity control unit 24, and converts the data input from the spreading unit 22 into downlink time slots DL # 1 to DL # 1.
The data is distributed to each DL # N and output to the corresponding first to Nth time slot diversity controllers 241 to 24n.

The diversity control unit 24 is connected to the distribution unit 23, the transmission processing unit 25, the uplink channel estimation unit 26, and the uplink demodulation processing unit 27. The diversity control unit 24 determines each time slot DL for downlink.
This is a downlink time slot diversity control unit including first to N-th time slot diversity control units 241 to 24n (corresponding to diversity control means) corresponding to # 1 to DL # N.

The first to N-th time slot diversity control units 241 to 24n provide corresponding downlink time slots DL # 1 to DL # 1 according to the channel estimation result for the uplink channel and the switching timing determination result.
In DL # N, it is determined whether or not transmission diversity is applied (necessity of transmission diversity). Also, the first to first
Nth time slot diversity control units 241 to 24n
Determines what kind of transmission diversity is to be applied (the type of transmission diversity).

The first to N-th time slot diversity controllers 241 to 24n perform diversity control according to the above-mentioned determination result. The type of transmission diversity includes, for example, STD, TxAA, TSTD, and the like.

The transmission processing unit 25 includes the diversity control unit 2
4 and antennas A1 and A2. The transmission processing unit 25 performs a predetermined process (for example, a transmission system selection process, a weighting process for each transmission system, etc.) on the data input from the diversity control unit 24 according to the corresponding transmission diversity. Further, the transmission processing unit 25 performs a filtering process on the data as necessary, and transmits the data to the mobile station 10 via the channels by the antennas A1 and A2.

The uplink channel estimator 26 is connected to the diversity controller 24 and the antennas A1 and A2. The uplink channel estimator 26 calculates the antenna A
By monitoring the channel for uplink via 1 and A2, the state of the channel (for example, waveform distortion, delay fluctuation, amplitude fluctuation, phase shift, etc.), that is, a fading complex envelope is estimated. The uplink channel estimator 26 transmits the result of the channel estimation to the diversity controller 2
4 is output.

The uplink demodulation processing section 27 is connected to the diversity control section 24 and the antennas A1 and A2. The uplink demodulation processing unit 27 includes antennas A1, A2
, Demodulates uplink data received via a channel, extracts a determination result of transmission diversity switching timing from the data, and outputs the result to the diversity control unit 24.

Next, the operation of the first embodiment will be described with reference to FIGS. FIG. 4 is a flowchart for explaining the operation of the mobile station 10 in the present embodiment. First, in S1, the mobile station 10 causes the downlink demodulation processing unit 11 to perform demodulation processing on data received via a channel.

At S 2, the mobile station 10 determines, based on the data demodulated by the downlink demodulation processing section 11, the downlink time slot DL #
Radio quality index values for each of 1 to DL # N are measured, and switching timing of transmission diversity is determined based on the measured radio quality index values. Since the process of S2 is a process that makes up the essentials of the wireless communication control technology according to the present invention, a method of determining the switching timing by the mobile station 10 will be described in more detail below.

For example, a time slot for downlink #
Transmission diversity is applied in 3 to # 7, and
When transmission diversity is not applied in # 8 to # 15, the switching timing determination unit 12 compares the signal power to interference power ratio SIR7 of # 7 and the signal power to interference power ratio SIR8 of # 8. As a result of the comparison, SIR7 <S
In the case of IR8, the switching timing determination unit 12 determines that the switching timing should be changed one time slot before, and outputs the determination result to the transmission processing unit 13. On the other hand, if SIR7> SIR8, the switching timing determination unit 12 determines that the switching timing should be changed after one time slot, and outputs the determination result to the transmission processing unit 13.

Further, as shown in FIG. 5A, a frame F1 including time slots # 1 to # 15 is assumed. When STD is applied in downlink time slots DL # 3 to DL # 9 and TSTD is applied in DL # 10 to DL # 15, switching timing determination section 12 determines reception power RxPower9 of DL # 9. And DL
The received power is compared with the received power RxPower10 of # 10.

As a result of the comparison, RxPower9 <Rx
In the case of Power 10, the switching timing determination unit 12
Transmits the determination result notifying that “the switching timing is to be changed one time slot in time” to the transmission processing unit 13.
Output to On the other hand, RxPower9> RxP
In the case of the power 10, a determination result notifying that “the switching timing is changed later by one time slot” is output to the transmission processing unit 13.

Assuming the frame F1 shown in FIG. 5A, the downlink time slots DL # 3 to DL # 3
STD antenna Al is applied in DL # 8, and STD antenna A is used in DL # 9 to DL # 15.
2 is applied, the switching timing determination unit 12
Is the ratio C of the desired signal power to the DL # 8 interference signal.
The ratio CIR9 of the desired signal power to the interference signal of IR8 and DL # 9 is compared.

As a result of the comparison, if CIR8 <CIR9, the switching timing determination unit 12 sends the transmission processing unit 13 a determination result indicating that the switching timing is to be changed one time slot in time. Output. On the other hand, if CIR8> CIR9, the switching timing determination unit 12 outputs to the transmission processing unit 13 a determination result indicating that the switching timing is changed to one switching time later.

Note that the result of the above determination is “change the switching timing one time slot earlier (or later)”.
, "1 time slot" may be replaced with "2 time slot" or "3 time slot". Also, as the determination result of the switching timing, “DL # 7
And a switching result such as "switching between DL and # 8" or "switching from the eighth downlink time slot". Further, the switching timing is not limited to one, and a plurality of switching timings such as two, three, or the like may be provided.
Is not limited to one and may output a determination result regarding a plurality of switching timings.

The switching timing determination section 12 may transmit the radio quality index values of all downlink time slots to the radio base station 20 instead of the switching timing determination result. In this case, the diversity control unit 24 of the radio base station 20 determines the switching timing based on the radio quality index value of the time slot for downlink from the mobile station 10, and determines the switching timing and the channel estimation result for the uplink channel. Based on this, transmission diversity control is performed for each time slot.

Returning to FIG. 4, in S3, the mobile station 10 causes the transmission processing unit 13 to add the switching timing determination result in S2 to the data for uplink. Mobile station 10
Performs a filtering process on the uplink data including the determination result by the transmission processing unit 13 and transmits the data to the wireless base station 20 via the antenna unit A.

FIG. 6 shows a radio base station 2 according to this embodiment.
9 is a flowchart for explaining the operation of the “0”. First,
At T1, the radio base station 20 receives the downlink data transmitted via the channel by the coding unit 21, performs coding and interleaving on the data, and outputs the data to the spreading unit 22.

At T2, the radio base station 20
For the data input from 1 by the spreading unit 22,
The data is subjected to spreading processing and scrambling, and the data is output to the distribution unit 23.

At T3, the radio base station 20
, The data input from spreading section 22 is divided into downlink time slots DL # 1 to DL # N, and the divided data is divided into corresponding first to Nth time slot diversity control sections 241 to 24n. And output.

At T4, the wireless base station 20
According to the channel estimation result for the uplink channel and the determination result of the switching timing by the time slot diversity control units 241 to 24n, whether to apply the transmission diversity in the corresponding downlink time slots DL # 1 to DL # N. Determine whether or not. In addition, the radio base station 20 determines the type of transmission diversity using the first to Nth time slot diversity controllers 241 to 24n.

At T5, the wireless base station 20
The time slot diversity controllers 241 to 24n perform diversity control according to the transmission diversity determined in T4. The process of T5 is a process that makes the key to the wireless communication control technology according to the present invention.
A method of controlling diversity by the radio base station 20 will be described in more detail.

For example, assume that the frame F1 shown in FIG. 5A is used. More specifically, the third to seventh time slot diversity control units 243 to 247 determine to apply transmission diversity in DL # 3 to DL # 7, and the eighth to fifteenth time slot diversity control units 248 to 2415 Are DL # 8 to DL # 15
It is assumed that the transmission diversity is determined not to be applied in.

In such a case, suppose that diversity control section 24 receives control information from uplink demodulation processing section 27 in the next frame instructing to "change the switching timing forward by one time slot". ,
Third to sixth time slot diversity controllers 243 to
246 can decide to apply transmit diversity in DL # 3 to DL # 6. The seventh to fifteenth time slot diversity controllers 247 to 2415 are DL
It is possible to determine that transmission diversity is not applied in # 7 to DL # 15.

In the frame F1, the third to ninth frames
Time slot diversity control units 243 to 249 are D
In L # 3 to DL # 9, it is determined that STD is to be applied, and the tenth to fifteenth time slot diversity controllers 2410 to 2415 determine whether to apply the STD in DL # 10 to DL # 15.
It is assumed that TD is determined to be applied.

In the above case, it is assumed that diversity control section 24 receives control information from uplink demodulation processing section 27 in the next frame, instructing to "change the switching timing to two time slots later in time". ,
Third to eleventh time slot diversity controllers 243
2411 can apply STD in DL # 3 to DL # 11. Also, the twelfth to fifteenth time slot diversity controllers 2412 to 2415 are DL
It is possible to determine to apply TSTD in # 12 to DL # 15.

To give a further example, the third to eighth time slot diversity controllers 243 to 248 may be DL # 3 to DL # 3.
When L # 8 determines to select antenna A1 by STD, and ninth to fifteenth time slot diversity controllers 249 to 2415 determine to apply antenna A2 by STD in DL # 9 to DL # 15 Is assumed.

In such a case, suppose that the diversity control unit 24 receives control information from the uplink demodulation processing unit 27 in the next frame instructing to "change the switching timing forward by one time slot". ,
Third to seventh time slot diversity controllers 243 to
247 can determine to select antenna A1 by STD in DL # 3 to DL # 7. Eighth to first
5 time slot diversity control units 248 to 2415
Are DL # 8 to DL # 15, and STD
2 can be decided.

At T6, the radio base station 20 applies the processing according to the corresponding transmission diversity to the data input from the diversity control section 24 by the transmission processing section 25, and then performs the filtering processing on the data. Alms,
The signal is transmitted to the mobile station 10 via the antennas A1 and A2.

Hereinafter, the operation and effect of the mobile communication system according to the first embodiment will be described. According to the mobile communication system of the present embodiment, in the mobile station 10, the switching timing determination unit 12 determines whether switching timing of transmission diversity is appropriate, and transmits the switching timing determination result to the radio base station 20 on the uplink.
Also, in the radio base station 20, the downlink first to N-th
The time slot diversity control units 241 to 24n
Based on the switching timing determination result from the mobile station 10, transmission diversity to be applied is controlled for each downlink time slot (DL # 1 to DL # N).

According to the present invention, when the radio base station 20 performs channel estimation with reference to an uplink time slot,
It was made with a concern that a mismatch between the fading frequency and the transmission diversity switching timing might occur due to the time difference between the time when the wireless base station 20 transmits data via the downlink time slot. Things.
In the present invention, the type of transmission diversity and the timing of switching ON / OFF are dynamically controlled according to the fading frequency.

More specifically, as shown in FIG. 7 (a), at time t1 when the fading frequency is low, the timing at which the estimation accuracy of the channel is lowered is late, so that the timing is compared with the conventional transmission diversity switching timing TM0. The transmission diversity is switched at the later switching timing TM1. On the other hand, as shown in FIG. 7B, at time t2 when the fading frequency is high, the timing at which the channel estimation accuracy decreases is earlier, so that the switching timing TM2 is earlier than the conventional switching timing TM0. Transmission diversity is switched. In FIGS. 7A and 7B, the fading complex envelope indicated by a solid line corresponds to the antenna A1, and the fading complex envelope indicated by a broken line corresponds to the antenna A2.

As described above, according to the mobile communication system 100 of the present invention, the timing at which the accuracy of the channel estimation for the uplink is reduced is predicted, and the timing is determined for each time slot under various fading frequencies. Optimal transmission diversity can be applied. As a result, it is possible to reduce degradation of downlink communication quality. The reduction in the deterioration of the communication quality contributes to the reduction in the retransmission rate due to transmission errors, and as a result, the data transmission capacity (throughput) per unit time in the entire system is improved.

The radio base station 20 determines ON / OFF of the transmission diversity itself. Thereby, for example, when it is predicted that desired communication quality is not obtained despite execution of transmission diversity, or when the channel estimation result is sufficiently good to secure a predetermined communication quality, If the radio base station 20 does not perform the transmission diversity, it is possible to reduce the processing load and the usage of the radio resources due to the control of the transmission diversity.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described. Since the basic configuration of the mobile communication system according to the present embodiment is the same as the configuration of the mobile communication system according to the first embodiment, each component is denoted by the same reference numeral, and the description thereof is omitted.
The differences from the third embodiment will be described in detail.

That is, in the first embodiment, the mobile station 1
0 indicates that the switching timing determination result is transmitted to the radio base station 20 for each frame. In the second embodiment, the mobile station 10 determines the switching timing over a longer span, that is, over a plurality of frames. I do. Then, the mobile station 10 sums up the determination results for a plurality of frames, and determines the determination result of the switching timing for the plurality of frames based on a predetermined determination criterion. The determination result is transmitted to the wireless base station 20 via the uplink at a rate of once for a plurality of frame transmissions.

For example, the mobile station 10 calculates the average of the time slot numbers at which the switching timing should be performed for 10 frames, and uses the average value of the time slot numbers as the calculation result as the switching timing for a plurality of frames. It transmits to the radio base station 20 once every 10 frames. In this case, the radio base station 20 performs the transmission diversity control at the same switching timing for each frame until receiving the switching timing determination result for a plurality of frames from the mobile station 10 as in the related art.

As a modification of the second embodiment,
The mobile station 10 transmits the determination result of the switching timing to the radio base station 20 for each frame, and the radio base station 20 tallies the determination result transmitted from the mobile station 10 for each frame for a plurality of frames. It is also possible to adopt a mode in which the switching timing is determined based on the judgment criterion. Also in this case, the radio base station 20 performs the transmission diversity control at the same switching timing for each frame as before, until the next switching timing is determined.

Further, as another modification of the second embodiment, the mobile station 10 aggregates the switching timing determination results of a predetermined number of frames that are temporally before an arbitrary time and performs a predetermined determination. A switching timing determination result for a plurality of frames is determined based on a criterion. Then, the mobile station 10
It is also possible to adopt a mode in which the determined result is transmitted to the radio base station 20 for each frame.

For example, when the time slot shown in FIG. 5A is used, the mobile station 10 transmits the switching timing determination result using UL # 2 of the Nth frame and transmits the determination result. As a result, a value obtained by averaging the switching timing determination results from the (N-10) th frame to the (N-1) th frame is transmitted. In this case, the mobile station 10
When transmitting the determination result of the switching timing using UL # 2 of the (N + 1) th frame, the determination result of the switching timing from the (N-9) th frame to the Nth frame is averaged as the determination result. Send the value.

As still another modification of the second embodiment, the mobile station 10 transmits the switching timing determination result to the radio base station 20 for each frame, and the radio base station 20
The determination result transmitted from the mobile station 10 for each frame is stored as needed. Subsequently, when performing the transmission diversity control, the radio base station 20 sums up the switching timing determination results of a predetermined number of frames that are temporally earlier than the time, and for each frame based on a predetermined determination criterion. Alternatively, the switching timing may be determined.

For example, when the time slots shown in FIG. 5A are used, the radio base station 20 transmits the diversity in the downlink time slots for DL # 3 to DL # 15 of the Nth frame. Control (hereinafter,
This is referred to as “downlink transmission diversity control”. )), The switching timing in the N-th frame is determined from the determination result of the switching timing from the (N-10) th frame to the (N-1) th frame. Then, the radio base station 20 performs downlink transmission diversity control for each time slot.

In such a case, the radio base station 20 sets the (N +
1) When performing downlink transmission diversity control on DL # 3 to DL # 15 of a frame, the (N + 1) th frame is referred to with reference to the determination result of the switching timing from the (N-9) th frame to the Nth frame. , The downlink transmission diversity control is performed for each time slot.

As described above, in the mobile communication system according to the second embodiment, the switching timing is determined over a longer span using a plurality of frames. Therefore, it is possible to reduce the error of the switching timing determination result due to the sudden change in the communication environment as much as possible, and to determine the switching timing with higher accuracy. Also, there is an advantage that the switching timing itself can be prevented from changing more than necessary between frames.

(Third Embodiment) Next, the third embodiment of the present invention will be described.
An embodiment will be described. Since the basic configuration of the mobile communication system according to the present embodiment is the same as the configuration of the mobile communication system according to the first embodiment, each component is denoted by the same reference numeral, and the description thereof is omitted.
The differences from the third embodiment will be described in detail.

That is, in the first embodiment, the mobile station 1
In the present embodiment, the mobile station 10 prepares a frame for determining the switching timing at predetermined time intervals (selection). The switching timing is determined only for that frame. For other frames, the switching timing determination result determined in the switching timing determination frame is diverted,
The radio base station 20 performs transmission diversity control.

For example, the radio base station 20 performs transmission using only one transmission antenna (for example, antenna A1) without performing transmission diversity control for any five consecutive frames out of 100 frames. The mobile station 10 determines the switching timing described in the first embodiment only for the above five frames. That is, the mobile station 10
Measures the SIR of each time slot in the five frames, and estimates the period of the channel fluctuation due to fading with reference to the temporal change of the SIR. Then, the mobile station 10 determines a point in time when the accuracy of the uplink channel estimation value in performing the diversity control decreases, that is, a switching timing.

Further, as another modification of the third embodiment, the radio base station 20 performs the TSTD only for any 10 consecutive frames out of 200 frames. The mobile station 10 determines the switching timing described in the first embodiment only for the above 10 frames. That is,
The mobile station 10 determines that the SIR of the time slot using one transmission antenna (eg, antenna A1) is greater than the SIR of the time slot using the other transmission antenna (eg, antenna A2) with respect to the time slots in the 10 frames. Measure large time intervals. This allows
The mobile station 10 can estimate a time interval in which the transmission diversity using the antenna selected when the radio base station 20 performs the TSTD is effective.

More specifically, as shown in FIG. 8, for frame F3 having downlink time slots DL # 4 to DL # 15, downlink data from antenna A1 and downlink data from antenna A2 are used. Is assumed to be alternately received. In such a case, the mobile station 10
Measures the SIRs of DL # 4 and DL # 5, respectively,
It is determined that the SIR of downlink data from antenna A1 in DL # 5 is larger than the other.

The mobile station 10 has DL # 6, DL # 7, DL
Similarly, by comparing SIRs of # 8 and DL # 9, DL # 10 and D # 11, DL # 12 and DL # 13, and DL # 14 and DL # 15, the time from one transmitting antenna is obtained. Time intervals where the SIR of the slot is greater than the SIR of the time slot from the other transmit antenna can be measured.

As described above, in the mobile communication system according to the third embodiment, the mobile station 10 determines the switching timing at a certain time interval. Since it is rare that the fading frequency fluctuates rapidly, there is little danger that the determination accuracy will be extremely reduced even if the switching timing determination interval is extended in this way. Thereby, the processing data amount of the mobile station 10 can be reduced as compared with the case where the switching timing is determined for each frame for every frame. Since the processing capacity of the mobile station 10 is limited, reduction of the processing data amount is particularly effective. Further, the traffic capacity between the mobile station 10 and the radio base station 20 is reduced.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described.
An embodiment will be described. Since the basic configuration of the mobile communication system according to the present embodiment is the same as the configuration of the mobile communication system according to the first embodiment, each component is denoted by the same reference numeral, and the description thereof is omitted.
The differences from the third embodiment will be described in detail.

In the first to third embodiments, the determination of the switching timing is used for the control of the transmission diversity. In the present embodiment, for example, the control of the transmission power supplied to the channel and the adaptive modulation And so on. In other words, according to the mobile communication system of the present embodiment, the fading frequency can be obtained while performing the downlink transmission diversity control.

For example, when the time slot shown in FIG. 5A is used, the radio base station 20 determines, based on DL # 9 and DL # 10, the antenna to be selected in the STD as the switching timing determination result. Assuming that information instructing switching between the mobile stations is received from the mobile station 10, the radio base station 20 controls the transmission power based on the information.

On the other hand, radio base station 20 receives from mobile station 10 information indicating that the antenna to be selected in the STD is to be switched between DL # 5 and DL # 6 as a result of the switching timing determination. Suppose you did. In this case, since the fading frequency in the current wireless environment is very large, the radio base station 20 determines that sufficient effects cannot be obtained even if the transmission power control is performed, and does not perform the transmission power control.

Further, for example, it is possible to perform adaptive modulation for switching a modulation method to be applied according to a wireless environment. That is, when the time slot shown in FIG. 5A is used, the radio base station 20 changes the transmission diversity method between DL # 12 and DL # 13 from STD to TSTD as the switching timing determination result. Is assumed to be received from the mobile station 10. In this case, the radio base station 20 determines that the fading frequency in the current radio environment is low, and uses 16QA as the modulation method.
Select M.

On the other hand, the radio base station 20 determines that the DL #
4 and DL # 5, the mobile station 1 transmits information indicating that the transmission diversity method is switched from STD to TSTD.
Suppose that it is received from 0. In this case, the radio base station 20
It is determined that the fading frequency in the current wireless environment is large, and QPSK is selected as the modulation method.

As described above, according to the mobile communication system of the fourth embodiment, mobile station 10 determines the timing at which the accuracy of uplink channel estimation is reduced in order to determine the timing of switching transmission diversity. Predict. Estimating the timing at which the accuracy of channel estimation decreases is equivalent to estimating a fading frequency, which is very important information in performing wireless communication.
The versatility of the present invention is enhanced by applying this fading frequency not only to switching timing determination, but also to transmission power control, adaptive modulation, and the like.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described.
An embodiment will be described. Since the basic configuration of the mobile communication system according to the present embodiment is the same as the configuration of the mobile communication system according to the first embodiment, each component is denoted by the same reference numeral, and the description thereof is omitted.
The differences from the third embodiment will be described in detail.

In the first to fourth embodiments, TDMA is used as a communication method between the mobile station 10 and the radio base station 20.
Although a scheme and a TDD scheme (that is, a scheme using a time slot as a channel) are assumed, the fifth embodiment assumes a CDMA scheme (that is, a scheme using a spreading code as a channel).

In the present embodiment, mobile station 10
The switching timing determination unit 12 measures a radio quality index value for each downlink time slot DL # 1 to DL # N for each spreading code, and transmits a switching timing determination result obtained from the radio quality index value to a transmission process. Output to the unit 13. In the radio base station 20, the diversity control unit 24
Performs diversity control for each spreading code. Then, the distribution unit 23 divides the data input from the spreading unit 22 for each spreading code, and transmits the divided data for each spreading code to the corresponding first to N-th diversity control units 241 to 24n. Thus, the present invention can be applied to a wider technical field.

Finally, a program for realizing the wireless communication control technology according to the present invention and a computer-readable recording medium (hereinafter, simply referred to as a “recording medium”) on which the program is recorded will be described. A recording medium is a means for causing a reading device provided in a hardware resource such as a general-purpose computer to change a state of energy, such as magnetism, light, or electricity, according to a description content of a program, and to output a signal corresponding thereto. In a format, the program description can be transmitted to the reader. Such a recording medium is, for example, a UIM (User Identity Modu).
le), etc., such as an IC card, a magnetic disk, an optical disk, and a magneto-optical disk, which are detachably mounted on a computer (including a portable terminal), and a hard disk (HD) fixedly incorporated in the computer, A non-volatile semiconductor memory such as firmware that is integrally fixed corresponds to this.

The above program is partially or wholly transferred from another device via a transmission medium such as a communication line.
The present invention may be configured to be received and recorded by the radio base station or the mobile station according to the present invention. Conversely, the program may be transmitted from the wireless base station or the mobile station according to the present invention to another device via a transmission medium and installed.

[0129]

According to the present invention, the switching timing of the transmission diversity is determined based on the radio quality index value measured by the mobile station, and this determination result is fed back to the radio base station. As a result, transmission diversity can be switched at a different suitable timing for each frame. That is, dynamic control of transmission diversity switching timing according to the fading frequency becomes possible. As a result, degradation of downlink communication quality can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a mobile communication system.

FIG. 2 is a block diagram showing a functional configuration of a mobile station.

FIG. 3 is a block diagram illustrating a functional configuration of a wireless base station.

FIG. 4 is a flowchart illustrating an operation of a mobile station.

FIG. 5A is a schematic diagram illustrating an example of a frame including 15 time slots, and FIG. 5B is a schematic diagram illustrating another example of a frame including 15 time slots. FIG.

FIG. 6 is a flowchart for explaining the operation of the wireless base station.

FIG. 7 is a diagram conceptually showing a transmission diversity switching timing at time t1, and a diagram conceptually showing a transmission diversity switching timing at time t2.

FIG. 8 is a schematic diagram showing an example of a frame including 15 time slots in the third embodiment.

[Explanation of symbols]

10 mobile station, 11 downlink demodulation processing unit, 12 switching timing determination unit, 13 transmission processing unit, 20 radio base station, 21 encoding unit, 22 spreading unit, 23 distribution unit,
24: Diversity control unit, 241 to 24n: 1st to Nth time slot diversity control unit, 25: Transmission processing unit, 26: Uplink channel estimation unit, 27: Uplink demodulation processing unit, C: Cell

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takayuki Ishiguro             2-11-1, Nagatacho, Chiyoda-ku, Tokyo, Japan             NTT DoCoMo F term (reference) 5K028 AA01 BB04 DD01 DD02 HH00                       QQ01                 5K059 CC02 DD07 DD16                 5K067 AA02 AA23 BB04 BB21 CC04                       CC24 DD43 EE02 EE10 GG01                       HH21 HH22

Claims (37)

[Claims] 1. A determining means for measuring a wireless quality index value for each downlink time slot, and determining a switching timing of transmission diversity based on the wireless quality index value, and a determination result of the switching timing by the determining means. Transmitting means for transmitting to the radio base station using the uplink. 2. The method according to claim 1, wherein the determining unit determines a switching timing of the transmission diversity at a predetermined time interval, and totals the determination result. The mobile station according to claim 1, wherein the mobile station is used for transmission to the radio base station. 3. A radio base station for communicating with a mobile station according to claim 1, wherein said channel estimation means performs channel estimation for an uplink time slot; and said switching timing transmitted from said mobile station. A determination result receiving unit that receives the determination result of the above, a channel estimation result by the channel estimation unit, and transmission for each downlink time slot based on the determination result of the switching timing received by the determination result receiving unit. Diversity control means for controlling diversity, and using transmission diversity controlled by the diversity control means, comprising a data transmission means for transmitting data to the mobile station on the downlink time slot, Wireless base station. 4. A radio base station for communicating with a mobile station according to claim 2, wherein said determination result receiving means receives a total result of said switching timing transmitted by a transmission means of said mobile station. 4. The diversity control unit according to claim 3, wherein the diversity control unit controls transmission diversity for each downlink time slot based on the channel estimation result and an aggregation result of the switching timing received by the determination result receiving unit. Wireless base station. 5. The diversity control means determines whether or not transmission diversity is required for each downlink time slot based on the channel estimation result and the switching timing determination result or aggregation result. The radio base station according to claim 3 or 4, wherein 6. The diversity control means determines a type of transmission diversity for each downlink time slot based on the channel estimation result and the switching timing determination result or the aggregation result. The radio base station according to claim 3. 7. The diversity control means determines an antenna to be used for data transmission in the STD for each downlink time slot based on the channel estimation result and the switching timing determination result or aggregation result. The radio base station according to claim 3 or 4, wherein: 8. A mobile station measures a radio quality index value for each downlink time slot, and determines a transmission diversity switching timing based on the radio quality index value. A decision result transmitting step of transmitting the decision result of the switching timing in the decision step to the radio base station using uplink, a channel estimation step of performing channel estimation for the uplink time slot, A determination result receiving step in which the wireless base station receives a determination result of switching timing transmitted from the mobile station in the determination result transmitting step; and the wireless base station receives the channel estimation result and the determination result reception. Based on the switching timing determination result received in the step, for each downlink time slot. A diversity control step of controlling transmission diversity, and a data transmission step of transmitting data to the mobile station on the downlink time slot using transmission diversity controlled in the diversity control step. A wireless communication control method comprising: 9. In the determining step, the mobile station determines a transmission diversity switching timing at a predetermined time interval and totals the determination result. In the determination result transmitting step, the mobile station performs the determination. Transmitting the totalized result of the switching timing in the step to the radio base station using an uplink, in the determination result receiving step, the radio base station totals the switching timing transmitted in the determination result transmitting step Receiving a result from the mobile station, in the diversity control step, the radio base station performs downlink based on the channel estimation result and the aggregation result of the switching timing received in the determination result receiving step, 9. The transmission diversity according to claim 8, wherein the transmission diversity is controlled for each time slot. A communication control method. 10. In the diversity control step, the radio base station determines whether or not transmission diversity is required for each downlink time slot based on the channel estimation result and the switching timing determination result or aggregation result. The wireless communication control method according to claim 8, wherein the method is determined. 11. In the diversity control step, the radio base station determines a type of transmission diversity for each downlink time slot based on the channel estimation result and the switching timing determination result or aggregation result. The wireless communication control method according to claim 8, wherein: 12. In the diversity control step, an antenna to be used for data transmission in STD is determined for each downlink time slot based on the channel estimation result and the switching timing determination result or aggregation result. The wireless communication control method according to claim 8 or 9, wherein: 13. A measuring means for measuring a radio quality index value for each downlink time slot, and a transmitting means for transmitting the radio quality index value measured by the measuring means to a radio base station using uplink. A mobile station comprising: 14. A radio base station for communicating with a mobile station according to claim 13, wherein: channel estimation means for performing channel estimation for an uplink time slot; and the radio quality transmitted from the mobile station. An index value receiving unit that receives an index value, based on the channel estimation result by the channel estimation unit and the radio quality index value received by the index value receiving unit, transmit diversity for each downlink time slot. A diversity control means for controlling; and a data transmission means for transmitting data to the mobile station on the downlink time slot using transmission diversity controlled by the diversity control means. base station. 15. The index value receiving means receives a radio quality index value at a predetermined time interval transmitted by a transmission means of the mobile station, and the diversity control means comprises: the channel estimation result, the index value 15. The radio base station according to claim 14, wherein transmission diversity is controlled for each downlink time slot based on a sum of the radio quality index values received by a receiving unit. 16. The diversity control means determines whether or not transmission diversity is required for each downlink time slot based on the channel estimation result and the radio quality index value or the sum of the radio quality index values. The radio base station according to claim 14, wherein: 17. The diversity control means determines the type of transmission diversity for each downlink time slot based on the channel estimation result and the radio quality index value or the sum of the radio quality index values. The radio base station according to claim 14, wherein: 18. The diversity control means, based on the channel estimation result and the radio quality index value or the aggregation result of the radio quality index value, assigns an antenna used for data transmission in STD to a downlink time slot. The radio base station according to claim 14, wherein the radio base station is determined every time. 19. A measuring step in which a mobile station measures a radio quality index value for each downlink time slot, and wherein the mobile station uses the uplink to measure the radio quality index value measured in the measuring step. An index value transmitting step of transmitting to the radio base station, the radio base station performs channel estimation for an uplink time slot, and the radio base station performs the index value transmitting step. An index value receiving step of receiving the radio quality index value transmitted from the mobile station; and the radio base station, a channel estimation result in the channel estimation step, and the radio quality index received in the index value receiving step. A diversity control step of controlling transmission diversity for each downlink time slot based on the A data transmission step of transmitting data to the mobile station on the downlink time slot using transmission diversity controlled in the diversity control step. . 20. In the index value receiving step, the radio base station receives a radio quality index value at a predetermined time interval transmitted from the mobile station. In the diversity control step, the radio base station includes: 20. The wireless communication control according to claim 19, wherein transmission diversity is controlled for each downlink time slot based on the channel estimation result and the aggregation result of the wireless quality index values received in the index value receiving step. Method. 21. In the diversity control step, the radio base station transmits, for each downlink time slot, based on the channel estimation result and the radio quality index value or the aggregation result of the radio quality index value. 21. A method for determining whether or not diversity is required.
3. The wireless communication control method according to 1. 22. In the diversity control step, the radio base station transmits, for each downlink time slot, based on the channel estimation result and the radio quality index value or the sum of the radio quality index values. 21. The type of diversity is determined.
3. The wireless communication control method according to 1. 23. In the diversity control step, the radio base station uses an antenna used for data transmission in STD based on the channel estimation result and the radio quality index value or a total result of the radio quality index value. 21. The wireless communication control method according to claim 19, wherein is determined for each downlink time slot. 24. A frame selecting means for selecting a frame to be used in determining switching timing of transmission diversity, and measuring a radio quality index value for each downlink time slot included in the frame selected by the frame selecting means. And determining means for determining switching timing of transmission diversity based on the wireless quality index value, and transmitting means for transmitting a determination result of the switching timing by the determining means to a wireless base station using uplink. A mobile station characterized by the following. 25. Diversity control means for controlling transmission diversity for each downlink time slot included in a frame used in determining transmission diversity switching timing, and transmission diversity controlled by the diversity control means. A data transmitting unit for transmitting data to the mobile station on the downlink time slot; a channel estimating unit for performing channel estimation for the uplink time slot; A determination result receiving unit configured to receive a determination result of the switching timing, wherein the diversity control unit is configured to perform a determination based on the channel estimation result of the channel estimation unit and the determination result of the switching timing received by the determination result receiving unit. Frame other than the frame The transmission diversity is controlled for each downlink time slot included in the frame, and the data transmission unit controls transmission diversity controlled for each downlink time slot included in a frame other than the frame by the diversity control unit. A base station for transmitting data to the mobile station on the downlink time slot. 26. The diversity control means, according to the channel estimation result and the switching timing determination result, determines whether transmission diversity is required or not for each downlink time slot. Item 25
A wireless base station according to item 1. 27. The diversity control means determines a type of transmission diversity for each downlink time slot based on the channel estimation result and the switching timing determination result. 25
A wireless base station according to item 1. 28. The diversity control means determines an antenna used for data transmission in STD for each downlink time slot based on the channel estimation result and the switching timing determination result. 26. The radio base station according to claim 25, 29. A frame selection step in which a mobile station selects a frame to be used when determining transmission diversity switching timing; and wherein the mobile station is configured for a downlink included in the frame selected in the frame selection step. Measuring a radio quality index value for each time slot, and determining a transmission diversity switching timing based on the radio quality index value; andthe mobile station performs uplink switching on the determination result of the switching timing in the determination step. A transmitting step of transmitting to a radio base station by using: a first step in which the radio base station controls transmission diversity for each downlink time slot included in the frame.
A diversity control step, wherein the radio base station transmits data to the mobile station on the downlink time slot using transmission diversity controlled in the first diversity control step. A transmitting step; a channel estimating step in which the radio base station performs channel estimation on an uplink time slot; and the radio base station receives a determination result of switching timing in the frame transmitted from a mobile station. A determination result receiving step, and the radio base station, based on the channel estimation result in the channel estimation step and the determination result of the switching timing received in the determination result receiving step,
A second diversity control step of controlling transmission diversity for each downlink time slot included in a frame other than the frame, and the radio base station includes in the second diversity control step a frame other than the frame in the second diversity control step A second data transmission step of transmitting data to the mobile station on the downlink time slot using transmission diversity controlled for each downlink time slot. Control method. 30. In the second diversity control step, the radio base station determines whether transmission diversity is required for each downlink time slot based on the channel estimation result and the switching timing determination result. 30. The wireless communication control method according to claim 29, wherein: 31. In the second diversity control step, the radio base station determines the type of transmission diversity for each downlink time slot based on the channel estimation result and the switching timing determination result. The wireless communication control method according to claim 29, wherein the method is determined. 32. In the second diversity control step, based on the channel estimation result and the switching timing determination result, the radio base station sets an antenna used for data transmission in STD to a downlink time. 30. The radio communication control method according to claim 29, wherein the radio communication control method is determined for each slot. 33. A frame selecting means for selecting a frame to be used in determining transmission diversity switching timing, and measuring a radio quality index value for each downlink time slot included in the frame selected by the frame selecting means. A mobile station, comprising: a measuring unit that performs measurement, and a transmitting unit that transmits the wireless quality index value measured by the measuring unit to a wireless base station using an uplink. 34. Diversity control means for controlling transmission diversity for each downlink time slot included in a frame used when determining transmission diversity switching timing, and transmission diversity controlled by the diversity control means. A data transmitting unit for transmitting data to the mobile station on the downlink time slot; a channel estimating unit for performing channel estimation for the uplink time slot; An index value receiving means for receiving a radio quality index value, the diversity control means, based on the channel estimation result by the channel estimation means, the radio quality index value received by the index value receiving means, Downlink included in a frame other than the frame The transmission diversity is controlled for each time slot, and the data transmission means uses transmission diversity controlled for each downlink time slot included in a frame other than the frame by the diversity control means, and the downlink is used. A radio base station for transmitting data to the mobile station on a time slot for use. 35. A frame selecting step in which a mobile station selects a frame to be used when determining transmission diversity switching timing; and wherein the mobile station is configured for a downlink included in the frame selected in the frame selecting step. A measurement step of measuring a radio quality index value for each time slot; and a transmission step of transmitting the radio quality index value measured in the measurement step to a radio base station using an uplink, A first radio base station for controlling transmission diversity for each downlink time slot included in the frame;
A diversity control step, wherein the radio base station transmits data to the mobile station on the downlink time slot using transmission diversity controlled in the first diversity control step. A transmitting step; a channel estimating step in which the radio base station performs channel estimation on an uplink time slot; and the radio base station receives a radio quality index value in the frame transmitted from the mobile station. Index value receiving step, the radio base station, based on the channel estimation result in the channel estimation step and the radio quality index value received in the index value receiving step, included in frames other than the frame Second diversity system for controlling transmission diversity for each downlink time slot to be transmitted Control step, the radio base station uses the transmission diversity controlled for each downlink time slot included in a frame other than the frame in the second diversity control step, the downlink time slot And a second data transmission step of transmitting data to the mobile station. 36. A radio base station according to any one of claims 3 to 7, 25 to 28, wherein said radio base station is determined or determined by said mobile station determination means according to any one of claims 1, 2, and 24. A judgment result receiving step of receiving the aggregated transmission diversity switching timing, and the radio base station refers to the switching timing received in the judgment result receiving step, and the mobile station and the radio base station And a frequency estimating step of estimating a fading frequency between (i) and (ii). 37. An index value wherein the radio base station according to any one of claims 14 to 18 and 34 receives a radio quality index value from the mobile station according to any one of claims 13 and 33. A receiving step, wherein the radio base station refers to the radio quality index value received in the index value receiving step, and a frequency estimation step of estimating a fading frequency between the mobile station and the radio base station. And a fading frequency estimation method.