Transmission rate control method, mobile station and radio base station

In the conventional mobile communication system using an “Enhanced Uplink, the present invention improves a radio quality by preventing a decrease in a transmission rate of uplink user data, the decrease unintended by the radio base station Node B and caused by a false detection of a “Down” command in an RGCH.” A transmission rate control method according to the present invention includes: transmitting, from a radio base station to a mobile station, a relative transmission rate control channel for instructing to decrease the transmission rate of the uplink user data, only when the uplink user data transmitted from the mobile station has been successfully received.

TECHNICAL FIELD

The present invention relates to a transmission rate control method, a mobile station, and a radio base station, which controls a transmission rate of uplink user data.

BACKGROUND ART

In a conventional mobile communication system, in an uplink from a mobile station UE to a radio base station Node B, a radio network controller RNC is configured to determine a transmission rate of a dedicated channel, in consideration of radio resources of the radio base station Node B, an interference volume in an uplink, transmission power of the mobile station UE, transmission processing performance of the mobile station UE, a transmission rate required for an upper application, and the like, and to notify the determined transmission rate of the dedicated channel by a message in a layer-3(Radio Resource Control Layer) to both of the mobile station UE and the radio base station Node B.

Here, the radio network controller RNC is provided at an upper level of the radio base station Node B, and is an apparatus configured to control the radio base station Node B and the mobile station UE.

In general, data communications often cause burst traffic compared with voice communications or TV communications. Therefore, it is preferable that a transmission rate of a channel used for the data communications is changed fast.

However, as shown inFIG. 11, the radio network controller RNC integrally controls a plurality of radio base stations Node B in general. Therefore, in the conventional mobile communication system, there has been a problem that it is difficult to perform fast control for changing of the transmission rate of channel (for example, per approximately 1 through 100 ms), due to processing load, processing delay, or the like.

In addition, in the conventional mobile communication system, there has also been a problem that costs for implementing an apparatus and for operating a network are substantially increased even ff the fast control for changing of the transmission rate of the channel can be performed.

Therefore, in the conventional mobile communication system, control for changing of the transmission rate of the channel is generally performed on the order from a few hundred ms to a few seconds.

Accordingly, in the conventional mobile communication system, when burst data transmission is performed as shown inFIG. 12(a), the data are transmitted by accepting low-speed, high-delay, and low-transmission efficiency as shown inFIG. 12(b), or, as shown inFIG. 12(c), by reserving radio resources for high-speed communications to accept that radio bandwidth resources in an unoccupied state and hardware resources in the radio base station Node B are wasted.

It should be noted that both of the above-described radio bandwidth resources and hardware resources are applied to the vertical radio resources inFIG. 12.

Therefore, the 3rd Generation Partnership Project (3GPP) and the 3rd Generation Partnership Project 2 (3GPP2), which are international standardization organizations of the third generation mobile communication system, have discussed a method for controlling radio resources at high speed in a layer-1and a media access control (MAC) sub-layer (a layer-2) between the radio base station Node B and the mobile station UE, so as to utilize the radio resources effectively. Such discussions or discussed functions will be hereinafter referred to as “Enhanced Uplink (EUL)”.

As disclosed in the non-patent document 1, in a conventional mobile communication system using the “enhanced uplink,” the mobile station UE is configured to decrease the current transmission rate of uplink user data when the mobile station UE receives a relative transmission rate control channel (a relative grant channel: RGCH) instructing to decrease the transmission rate of uplink user data (that is, including a “Down” command) from the radio base station Node B.

Moreover, as disclosed in the non-patent document 1, an HARQ protocol is applied to the conventional mobile communication system using the “enhanced uplink.” Accordingly, the radio base station Node B is configured to transmit a positive transmission acknowledgement signal (Ack) to the mobile station every time a reception/decoding processing on each of the transmission data blocks included in the uplink user data has been successful. In contrast, the radio base station Node B is configured to transmit a negative transmission acknowledgement signal (Nack) to the mobile station when the reception/decoding processing has not been successful.

The mobile station UE is configured to continue retransmission of the same transmission data block until a positive transmission acknowledgment signal (Ack) is received at the mobile station UE, or until the number of retransmissions reaches the maximum retransmission number predetermined by the radio network controller RNC.

Here, when the mobile station UE has received a “Down” command via the RGCH, the mobile station UE is configured to decrease the transmission rate of the uplink user data regardless of “Ack/Nack/DTX” on an HICH.

Meanwhile, the radio base station Node B is configured to determine an increase or decrease of the transmission rate of the uplink user data, regardless of the result of a reception/decoding processing of the transmission data block, and to notify the determined result (an “Up” command or a “Down” command) to the mobile station UE via the RGCH.

In the conventional mobile communication system using the “enhanced uplink”, when the radio base station Node B transmits the negative transmission acknowledgment signal (Nack) due to a reception error at the radio base station Node B, the mobile station UE continues retransmission unless a reception error of “Ack/Nack” on the HICH occurs. Hence, the transmission rate of the uplink user data remains unchanged.

However, there has been a problem that, if the mobile station UE assumes a “DTX” included in the RGCH as the “Down” command, the mobile station UE decreases the transmission rate of the uplink user data, thereby a decrease unintended by the radio base station Node B in the transmission rate occurs.

DISCLOSURE OF THE INVENTION

The present invention has been made in view of the above-described problems, and its object is to provide a transmission rate control method, a mobile station, and a radio base station that make it possible to improve a radio quality by preventing a decrease in a transmission rate of uplink user data, the decrease unintended by the radio base station Node B and caused by a false detection of a “Down” command in an RGCH, in the conventional mobile communication system using an “Enhanced Uplink.”

A first aspect of the present invention is summarized as a transmission rate control method for controlling a transmission rate of uplink user data, including: transmitting, from a radio base station to a mobile station, a relative transmission rate control channel for instructing to decrease the transmission rate of the uplink user data, only when the uplink user data transmitted from the mobile station has been successfully received.

A second aspect of the present invention is summarized as a transmission rate control method for controlling a transmission rate of uplink user data, including: decreasing, at a mobile station, the transmission rate of the uplink user data in accordance with a relative transmission rate control channel for instructing to decrease the transmission rate of the uplink user data, only when a positive transmission acknowledgment signal from a radio base station has been received.

A third aspect of the present invention is summarized as a mobile station for transmitting uplink user data, including: a transmission rate control section configured to decrease a transmission rate of the uplink user data in accordance with a relative transmission rate control channel for instructing to decrease the transmission rate of the uplink user data, only when a positive transmission acknowledgment signal from a radio base station has been received.

A fourth aspect of the present invention is summarized as a radio base station used in a transmission rate control method for controlling a transmission rate of uplink user data, including: a relative grant channel transmitter configured to transmit, to a mobile station, a relative transmission rate control channel for instructing to decrease the transmission rate of the uplink user data, only when the uplink user data transmitted from the mobile station has been successfully received.

BEST MODES FOR CARRYING OUT THE INVENTION

(Mobile Communication System According to a First Embodiment of the Present Invention)

An explanation will be given for the configuration of a mobile communication system according to a first embodiment of the present invention with reference toFIGS. 1 to 8. Note that the mobile communication system according to this embodiment includes a plurality of radio base stations Node B#1to #5and a radio network controller RNC, as shown inFIG. 11.

In addition, in the mobile communication system according to this embodiment, a “High Speed Downlink Packet Access (HSDPA)” is used in a downlink, and an “Enhanced Uplink (EUL)” is used in an uplink. It should be noted that in both of the HSDPA and the EUL, retransmission control (N process stop and wait) shall be performed by a “Hybrid Automatic Repeat Request (HARQ)”.

Therefore, an Enhanced Dedicated Physical Channel (E-DPCH), configured of an Enhanced Dedicated Physical Data Channel (E-DPDCH) and an Enhanced Dedicated Physical Control Channel (E-DPCCH), and a Dedicated Physical Channel (DPCH), configured of a Dedicated Physical Data Channel (DPDCH) and a Dedicated Physical Control Channel (DPCCH), are used in the uplink.

Here, the E-DPCCH transmits control data for the EUL such as a transmission format number for defining a transmission format (transmission block size, or the like) of the E-DPDCH, HARQ related information (the number of retransmissions, or the like), and scheduling related information (transmission power, buffer residence-volume, or the like in the mobile station UE).

In addition, the E-DPDCH is paired with the E-DPCCH, and transmits user data for the mobile station UE based on the control data for the EUL transmitted through the E-DPCCH.

The DPCCH transmits control data such as a pilot symbol that is used for RAKE combining, SIR measurement, or the like, a Transport Format Combination Indicator (TFCI) for identifying a transmission format of uplink DPDCH, and a transmission power control bit in a downlink.

In addition, the DPDCH is paired with the DPCCH, and transmits user data for the mobile station UE based on the control data transmitted through the DPCCH. However, if user data to be transmitted does not exist in the mobile station UE, the DPDCH can be configured not to be transmitted.

In addition, in the uplink, a “High Speed Dedicated Physical Control Channel (HS-DPCCH)” and a Random Access Channel (RACH) are used, both of which are required when the HSPDA is applied.

The High Speed Dedicated Physical Control Channel (HS-DPCCH) transmits a Channel Quality Indicator (CQI) and a transmission acknowledgement signal (“Ack” or “Nack”) for the HS-DPCCH.

As shown inFIG. 1, the mobile station UE according to this embodiment is provided with a bus interface31, a call processing section32, a baseband processing section33, a radio frequency (RF) section34, and a transmission-reception antenna35.

However, these functions can be independently present as a hardware, and can be partly or entirely integrated, or can be configured through a process of software.

The bus interface31is configured to forward user data outputted from the call processing section32to another functional section (for example, an application related functional section). In addition, the bus interface31is configured to forward user data transmitted from another functional section (for example, the application related functional section) to the call processing section32.

The call processing section32is configured to perform a call control processing for transmitting and receiving user data.

The baseband signal processing section33is configured to, acquire user data by performing a layer-1processing including a despreading processing, a RAKE combining processing, and a Forward Error Correction (FEC) decode processing, a Media Access Control (MAC) processing including a MAC-e processing and a MAC-d processing, and a Radio Link Control (RLC) processing, against the baseband signals transmitted from the RF section34, so as to transmit the acquired user data to the call processing section32.

In addition, the baseband signal processing section33is configured to generate the baseband signals by performing the RLC processing, the MAC processing, or the layer-1processing against the user data transmitted from the call processing section32so as to transmit the baseband signals to the RF section34.

Detailed description of the functions of the baseband signal processing section33will be given later. The RF section34is configured to generate baseband signals by performing the detection processing, the filtering processing, the quantization processing, or the like against radio frequency signals received via the transmission-reception antenna35, so as to transmit the generated baseband signals to the baseband signal processing section33.

As shown inFIG. 2, the baseband signal processing section33is provided with an RLC processing section33a, a MAC-d processing section33b, a MAC-e processing section33c, and a layer-i processing section33d.

The RLC processing section33ais configured to perform a processing (RLC processing) of an upper layer of a layer-2, against user data transmitted from the call processing section32so as to transmit the user data to the MAC-d processing section33b.

The MAC-d processing section33bis configured to attach a channel identifier header, and to generate the transmission format in the uplink in accordance with the transmission power limit in the uplink.

As shown inFIG. 3, the MAC-e processing section33cis provided with an Enhanced Transport Format Combination (E-TFC) selecting section33c1and an HARQ processing section33c2.

The E-TFC selecting section33c1is configured to determine a transmission format (E-TFC) of the E-DPDCH and the E-DPCCH, based on scheduling signals transmitted from the radio base station Node B.

In addition, the E-TFC selecting section33c1is configured to transmit transmission format information on the determined transmission format (that is, a transmission data block size, a transmission power ratio between the E-DPDCH and the DPCCH, or the like) to the layer-1processing section33d, and to transmit the determined transmission format information to the HARQ processing section33c2.

The E-TFC selecting section33c1is configured to decrease the transmission rate of the uplink user data to be transmitted in the following transmission, in accordance with the RGCH for instructing to decrease the transmission rate (including the “Down” command), only when the positive transmission acknowledgment signal (Ack) for the transmission data block has been received from the radio base station Node B. Here, the transmission data block is included in the uplink user data transmitted in the previous transmission.

Such scheduling signals are information notified in the cell where the mobile station UE is located, and include control information for all the mobile stations located in the cell, or a specific group of the mobile stations located in the cell.

The HARQ processing section33c2is configured to perform process control for the “stop-and-wait of N-process”, so as to transmit the user data in the uplink based on the transmission acknowledgement signals (Ack/Nack for uplink data) transmitted from the radio base station Node B.

Specifically, the HARQ processing section33c2is configured to determine, based on a CRC result entered from the layer-1processing section33d, whether or not the reception processing of the uplink user data has been successful. Then, the HARQ processing section33c2generates the transmission acknowledgement signal (Ack or Nack) based on the determination result, and transmits the generated transmission acknowledgement signal to the layer1processing section33d. When the determination result is “OK”, the HARQ processing section33c2transmits, to the MAC-d processing section33d, the downlink user data entered from the layer1processing section33d.

As shown inFIG. 4, the radio base station Node B according to this embodiment is provided with an HWY interface11, a baseband signal processing section12, a call control section13, at least one transmitter-receiver section14, at least one amplifier section15, and at least one transmission-reception antenna16.

The HWY interface11is an interface with a radio network controller RNC. Specifically, the HWY interface11is configured to receive user data transmitted from the radio network controller RNC to a mobile station UE via a downlink, so as to enter the user data to the baseband signal processing section12. In addition, the HWY interface11is configured to receive control data for the radio base station Node B from the radio network controller RNC, so as to enter the received control data to the call control section13.

In addition, the HWY interface11is configured to acquire, from the baseband signal processing section12, user data included in the uplink signals which are transmitted from a mobile station UE via an uplink, so as to transmit the acquired user data to the radio network controller RNC. Further, the HWY interface11is configured to acquire control data for the radio network controller RNC from the call control section13, so as to transmit the acquired control data to the radio network controller RNC.

The baseband signal processing section12is configured to generate baseband signals by performing such as the RLC processing, the MAC processing (MAC-d processing or MAC-e processing), and the layer-1processing against the user data acquired from the HWY interface11, so as to forward the generated baseband signals to the transmitter-receiver section14.

Here, the MAC processing in the downlink includes an HARQ processing, a scheduling processing, a transmission rate control processing, or the like. In addition, the layer-1processing in the downlink includes a channel coding processing of user data, a spreading processing, or the like.

In addition, the baseband signal processing section12is configured to extract user data by performing the layer-1processing, the MAC processing (MAC-d processing or MAC-e processing), and the RLC processing against the baseband signals acquired from the transmitter-receiver section14, so as to forward the extracted user data to the HWY interface11.

Here, the MAC-e processing in the uplink includes an HARQ processing, a scheduling processing, a transmission rate control processing, a header disposal processing, or the like. In addition, the layer-1processing in the uplink includes the despreading processing, the RAKE combining processing, an error correction decode processing, or the like.

Detailed description of the functions of the baseband signal processing section12will be given later. In addition, the call control section13is configured to perform a call control processing based on the control data acquired from the HWY interface11.

The transmitter-receiver section14is configured to perform a processing of converting baseband signals acquired from the baseband signal processing section12, into radio frequency signals (downlink signals), so as to transmit the converted radio frequency signals to the amplifier section15. In addition, the transmitter-receiver14is configured to perform a processing of converting the radio frequency signals (uplink signals) acquired from the amplifier section15, into the baseband signals, so as to transmit the converted baseband signals to the baseband signal processing section12.

The amplifier section15is configured to amplify the downlink signals acquired from the transmitter-receiver section14, so as to transmit the amplified downlink signals to the mobile station UE via the transmission-reception antenna16. In addition, the amplifier15is configured to amplify the uplink signals received by the transmission-reception antenna16, so as to transmit the amplified uplink signals to the transmitter-receiver section14.

As shown inFIG. 5, the baseband signal processing section12is provided with an RLC processing section121, a MAC-d processing section122, and a MAC-e and layer1processing section123.

The MAC-e and layer-1processing section123is configured to perform, against the baseband signals acquired from the transmitter-receiver section14, the despreading processing, a RAKE combining processing, an error correction decode processing, an HARQ processing, or the like.

The MAC-d processing section122is configured to perform a header disposal processing and the like, against an output signal from the MAC-e and layer1processing section123.

The RLC processing section121is configured to perform such as a retransmission control processing in the RLC layer, a reconstruction processing in an RLC-SDU or the like, against the output signals from the MAC-d processing section122.

However, these functions are not clearly divided per hardware, and can be acquired by software.

As shown inFIG. 6, the MAC-e and layer-1processing section (configuration for the uplink)123is provided with a DPCCH RAKE section123a, a DPDCH RAKE section123b, an E-DPCCH RAKE section123c, an E-DPDCH RAKE section123d, an HS-DPCCH RAKE section123e, an RACH processing section123f, a Transport Format Combination Indicator (TFCI) decoder section123g, buffers123hand123m, re-despreading sections123iand123n, FEC decoder sections123jand123p, an E-DPCCH decoder section123k, a MAC-e functional section123l, an HARQ buffer123o, and a MAC-hs functional section123q.

The E-DPCCH RAKE section123cis configured to perform the despreading processing and the RAKE combining processing by using a pilot symbol included in the DPCCH, against the E-DPCCH in the baseband signals transmitted from the transmitter-receiver section14.

The E-DPCCH decoder section123kis configured to acquire transmission format number related information, HARQ related information, scheduling related information, or the like, by performing the decode processing against the RAKE combining outputs of the E-DPCCH RAKE section123c, so as to enter the acquired information to the MAC-e functional section123l.

The E-DPDCH RAKE section123dis configured to perform a despreading processing by using the transmission format information (the number of codes) transmitted from the MAC-e functional section123land the RAKE combining processing using the pilot symbol included in the DPCCH, against the E-DPDCH in the baseband signals transmitted from the transmitter-receiver section14.

The buffer123mis configured to store the RAKE combining outputs of the E-DPDCH RAKE section123dbased on the transmission format information (the number of symbols) transmitted from the MAC-e functional section123l.

The re-despreading section123nis configured to perform a despreading processing against the RAKE combining outputs of the E-DPDCH RAKE section123dstored in the buffer123m, based on the transmission format information (a spreading factor) transmitted from the MAC-e functional section123l.

The HARQ buffer123ois configured to store the despreading processing outputs of the re-despreading section123n, based on the transmission format information transmitted from the MAC-e functional section123l.

The FEC decoder section123pis configured to perform an error correction decoding processing (the FEC decoding processing) against the despreading processing outputs of the re-despreading section123n, the outputs stored in the HARQ buffer123o, based on the transmission format information (transmission data block size) transmitted from the MAC-e functional section123l.

The MAC-e functional section123lis configured to calculate and output the transmission format information (the number of codes, the number of symbols, the spreading factor, the transmission data block size, and the like) based on the transmission format number related information, the HARQ related information, the scheduling related information, and the like, which are acquired from the E-DPCCH decoder section123k.

In addition, as shown inFIG. 7, the MAC-e functional section123lis provided with a receive processing command section123l1, an HARQ control section123l2, and a scheduling section123l3.

The receive processing command section123l1is configured to transmit, to the HARQ control section123l2, the transmission format number related information, the HARQ related information, and the scheduling related information, which are entered from the E-DPCCH decoder section123k.

In addition, the receive processing command section123l1is configured to transmit, to the scheduling section123l3, the scheduling related information entered from the E-DPCCH decoder123k.

Further, the receive processing command section123l1is configured to output the transmission format information corresponding to the transmission format number entered from the E-DPCCH decoder section123k.

The HARQ control section123l2is configured to determine whether or not the reception processing of uplink user data has been successful, based on the CRC result entered from the FEC decoder section123p. Then, the HARQ control section123l2is configured to generate the transmission acknowledgement signal (Ack or Nack), based on the determination result, so as to transmit the generated transmission acknowledgement signals to the configuration for the downlink of the baseband signal processing section12. In addition, the HARQ control section123l2is configured to transmit the uplink user data entered from the FEC decoder section123pto the radio network controller RNC, when the above determination result has been “OK”.

In addition, the HARQ control section123l2is configured to clear soft decision information stored in the HARQ buffer123owhen the above determination result is “OK”. On the other hand, when the above determination result is “NG”, the HARQ control section123l2is configured to store the uplink user data in the HARQ buffer123o.

In addition, the HARQ control section123l2is configured to forward the above determination result to the receive processing command section123l1. Then, the receive processing control command section123l1is configured to notify the E-DPDCH RAKE section123dand the buffer123mof a hardware resource to be prepared for the following transmission time interval (TTI), so as to perform notification for reserving the resource in the HARQ buffer123o.

In addition, when the uplink user data is stored in the buffer123m, the receive processing command section123l1is configured to instruct the HARQ buffer123oand the FEC decoder section123pto perform the FEC decoding processing after concatenating, per TTI, a newly received uplink user data and the uplink user data in a process corresponding to the TTI, the uplink user data stored in the HARQ buffer123o.

The scheduling section123l3is configured to transmit scheduling signals (such as the RGCH or the like) via a configuration for downlink.

Further, the scheduling section123l3is configured to transmit, to the mobile station UE, the RGCH for instructing to decrease the transmission rate (including the “Down” command) of the uplink user data to be transmitted in the following transmission, only when the reception/decoding processing on the transmission data block has been successful. Here, the transmission data block is included in the uplink user data transmitted from the mobile station UE in the previous transmission.

The radio network controller RNC according to the present embodiment is an apparatus located on upper level of the radio base station Node B and configured to control radio communication between the radio base station Node B and the mobile station UE.

As shown inFIG. 8, the radio network controller RNC according to this embodiment is provided with an exchange interface51, a Logical Link Control (LLC) layer processing section52, a MAC layer processing section53, a media signal processing section54, a radio base station interface55, and a call control section56.

The exchange interface51is an interface with an exchange1. The exchange interface51is configured to forward the downlink signals transmitted from the exchange1to the LLC layer processing section52, and to forward the uplink signals transmitted from the LLC layer processing section52to the exchange1.

The LLC layer processing section52is configured to perform an LLC (Logical Link Control) sub-layer processing such as a synthesis processing of a header (e.g. a sequence number), a trailer, or the like. The LLC layer processing section52is also configured to transmit the uplink signals to the exchange interface51and to transmit the downlink signals to the MAC layer processing section53, after the LLC sub-layer processing is performed.

The MAC layer processing section53is configured to perform a MAC layer processing such as a priority control processing or a header granting processing. The MAC layer processing section53is also configured to transmit the uplink signals to the LLC layer processing section52and to transmit the downlink signals to the radio base station interface55(or a media signal processing section54), after the MAC layer processing is performed.

The media signal processing section54is configured to perform a media signal processing against voice signals or real time image signals. The media signal processing section54is also configured to transmit the uplink signals to the MAC layer processing section53and to transmit the downlink signals to the radio base station interface55, after the media signal processing is performed.

The radio base station interface55is an interface with the radio base station Node B. The radio base station interface55is configured to forward the uplink signals transmitted from the radio base station Node B to the MAC layer processing section53(or the media signal processing section54) and to forward the downlink signals transmitted from the MAC layer processing section53(or the media signal processing section54) to the radio base station Node B.

The call control section56is configured to perform a radio resource control processing, a channel setup and open processing by the layer-3signaling, or the like. Here, the radio resource control processing includes a call admission control processing, a handover processing, or the like.

Descriptions will be given for an operation of the mobile communication system according to the first embodiment of the present invention with reference toFIGS. 9 and 10.FIG. 9shows an operation of a radio base station Node B according to the first embodiment of the present invention, andFIG. 10shows an operation of the radio base station Node B according to the first embodiment of the present invention.

As shown inFIG. 9, in step S101, the radio base station Node B receives a transmission data block including uplink user data transmitted from a mobile station UE.

In steps S102and S103, when a reception/decoding processing against the transmission data block has been successful, and when a decrease in a transmission rate of the uplink user data is required and is feasible, in step S104, the radio base station Node B transmits an RGCH including a “Down” command.

On the other hand, in steps S102and S103, when a reception/decoding processing against the transmission data block has not been successful or when the decrease in the transmission rate of the uplink user data is not required or is not feasible, in step S105, the radio base station Node B does not transmit the RGCH including the “Down” command.

As shown inFIG. 10, in step S201, the mobile station receives an HICH.

In steps S202and S203, when a positive transmission acknowledgment signal (Ack) was received via the HICH, and when the “Down” command is included in the received RGCH, in step S204, the mobile station UE decreases the transmission rate of the uplink user data.

On the other hand, in steps S202and S203, when a negative transmission acknowledgment signal (Nack) was received via the HICH, or when the “Down” command is not included in the received RGCH, in step S205, the mobile station UE does not decrease the transmission rate of the uplink user data.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and various modifications are possible.

INDUSTRIAL APPLICABILITY

As described above, according to the present invention, it is possible to provide a transmission rate control method, a mobile station, and a radio base station that make it possible to improve a radio quality by preventing a decrease in a transmission rate of uplink user data, the decrease unintended by the radio base station Node B and caused by a false detection of a “Down” command in an RGCH, in the conventional mobile communication system using an “Enhanced Uplink.”