JP2007259031A - Mobile communication system, and flow controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the overall throughput in a mobile communication system which includes a mobile station, a base station, and a base station controlling station; and in a flow controlling method. <P>SOLUTION: The base station 2 is so configured as to have a wireless unit 11 for performing wireless transmission and reception via a wireless zone Uu between the mobile station 1 and itself, a line processor 13 for performing transmission and reception via a wired zone Iub between the base station controlling station and itself, a call processor 14, and a flow controlling unit 19. The call processor 14 is equipped with a means which finds out the maximum allowable transmission rate in the wired zone Iub based on the transmittable rate determined based on the band usage rate of the wired zone Iub and the maximum transmittable rate in the wireless zone Uu, and sets it in the flow controlling unit 19. The flow controlling unit 19 is equipped with a means which notifies the call processor 14 of a request for updating the maximum allowable transmission rate, when the maximum allowable transmission rate is not more than the maximum transmittable rate based on the transmission capability of the mobile station 1 and the band usage rate of the wired zone Iub is not more than the threshold value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile communication system and a flow control method that can update a maximum allowable transmission rate in a wired section between a base station and a base station control station according to a traffic situation.

  The mobile communication system includes, for example, a mobile station (MS) 51, a base station (BTS) 52, a base station control station (RNC) 53, and a core network (CN) 54, as shown in FIG. The mobile station 51 has a function of performing wireless communication at an arbitrary position within the service area of the base station 52 or while moving in a service area of a different base station 52, and each base station 52 communicates with the mobile station 51. The base station control station 53 has a function of performing communication control in a wired section between the base station 52 and the core network 54. Is. The core network 54 includes a configuration in which a general telephone or a terminal device is connected via an exchange or the like not shown.

  As a wireless communication method between the mobile station 51 and the base station 52, for example, a W-CDMA (Wide-Code Division Multiple Access) method, an OFDM (Orthogonal Frequency Division Multiplexing) method, or the like is applied. Also, the base station 52 sends transmission power control information (TPC: Transmit Power Control) for controlling transmission power to the mobile station 51 according to the reception level (reception quality) such as a pilot signal from the mobile station 51 at regular intervals. It is possible to perform control to maintain transmission / reception quality. Further, in the W-CDMA system, an HSDPA (High Speed Downlink Packet Access) system that can increase the downlink packet transmission rate is defined. This method includes means for selecting, for example, a QPSK method or a 16-value QAM method in accordance with the state of the wireless section.

  In the base station 52 to which the HSDPA method that enables high-speed packet transmission is applied, the maximum allowable transmission rate (MAX rate) with the base station control station 53 is determined at the time of call setting. The MAX rate is set by adopting the smaller one of the transmission rate determined from the band usage status of the wired section at the time of call setting and the maximum transmission rate of the wireless section depending on the transmission capability of the mobile station 51. The base station 52 notifies the base station control station 53. The base station control station 53 performs transmission control of user data by setting the MAX rate notified from the base station 52 as an initial transmission rate. Also, the flow control between the base station 52 and the base station control station 53 in the base station 52 after the call setup is performed under the condition that the initially set MAX rate is not exceeded depending on the transmission quality status between the wireless section and the wired section. The base station 52 notifies the base station control station 53 as a transmission capacity allocation signal (CA (Capacity Allocation) signal).

In the base station control station, when the mobile station starts communication using the dedicated channel, the transmission rate is determined according to the situation at the start of communication, and this transmission rate is notified to the base station. Means have been proposed for continuous communication using dedicated channels at a transmission rate suitable for the line conditions (see, for example, Patent Document 1).
JP 2004-282169 A

  In the configuration of the conventional mobile communication system shown in FIG. 1, the flow control between the base station 52 and the base station control station 53 sets the MAX rate according to the band usage status of the wired section at the time of call setting. Yes, the set MAX rate is often less than the maximum transmission capability of the mobile station 51. While the call connection is ongoing, the base station 52 notifies the base station control station 53 of the transmittable rate determined according to the transmission quality status between the wireless section and the wired section by a CA (Capacity Allocation) signal. However, the MAX rate determined at the time of call setup is maintained as it is, and cannot be updated to a higher transmission rate. Accordingly, even when the transmission quality of the wireless section and the wired section is improved and the maximum transmission capability of the mobile station 51 can be exhibited as compared with the time of call setting, the transmission rate equal to or higher than the MAX rate initially set at the time of call setting. Thus, user data cannot be transmitted. Therefore, there is a problem that the maximum transmission rate of the mobile station 51 cannot be effectively used as the entire system.

  An object of the present invention is to solve the above-described problems of the conventional example, and to increase the above-mentioned MAX rate after call setting.

  The mobile communication system of the present invention is a mobile communication system including a base station that communicates with a mobile station via a wireless section and communicates with a base station control station via a wired section. A wireless unit that performs wireless transmission / reception via a section, a line processing unit that transmits / receives via the wired section, a call processing unit, and a flow control unit, wherein the call processing unit includes the wired section Means for determining the maximum allowable transmission rate of the wired section and setting it in the flow control section based on the transmittable rate determined based on the band usage rate of the wireless section and the maximum transmittable rate of the wireless section; Is the maximum allowable transmission rate of the wired section when the maximum allowable transmission rate set by the call processing unit is less than or equal to the maximum transmittable rate based on the transmission capability of the mobile station and the bandwidth usage rate of the wired section is less than or equal to a threshold value. Biography The rate of the update request comprises means for notifying the call processing unit.

  The base station also includes a database storing update widths corresponding to a plurality of types of priorities of transmission data referred to by the call processing unit that performs update processing in accordance with an update request for a maximum allowable transmission rate from the flow control unit. ing.

  The flow control method of the present invention is a flow control method in a mobile communication system including a base station that communicates with a mobile station through a wireless section and communicates with a base station control station through a wired section. At the time of setting, the smaller of the transmittable rate according to the band usage status of the wired section and the transmittable rate of the wireless section is set as the maximum allowable transmission rate of the wired section and notified to the base station control station Updating the transmittable rate of the wired section up to the set maximum allowable transmission rate of the wired section, and notifying the base station control station, wherein the maximum allowable transmission rate is the maximum based on the transmission capability of the mobile station Update the maximum allowable transmission rate of the wired section and notify the base station control station when the transmission rate is less than the transmission rate and the bandwidth usage rate of the wired section is less than the threshold It is intended to include that process.

  In addition, when the maximum allowable transmission rate of the wired section is updated, a process of updating according to an update width corresponding to the priority of the transmission data is included.

  In addition, when there are a plurality of update target mobile stations for the maximum allowable transmission rate in the wired section and the priority of the transmission data is different, a process of preferentially updating the maximum allowable transmission rate for transmission data having a high priority is included. .

  In the base station, if the maximum allowable transmission rate of the wired section set at the time of call setup is less than the maximum transmittable rate based on the transmission capability of the mobile station, the maximum allowable transmission rate can be improved by improving the transmission quality during communication. Update request is made, and the maximum allowable transmission rate can be reset based on the maximum transmission rate of the mobile station, whereby the throughput of the entire mobile communication system can be improved.

  Referring to FIG. 1, the mobile communication system of the present invention includes a base station 2 that communicates with a mobile station 1 via a radio section Uu and communicates with a base station control station 3 via a wired section Iub. The base station 2 includes a radio unit 11 that performs radio transmission / reception via the radio zone Uu, a line processing unit 13 that transmits / receives via the wired zone Iub, a call processing unit 14, and a flow control unit 19. The call processing unit 14 obtains the maximum allowable transmission rate of the wired section Iub based on the transmittable rate determined based on the band usage rate of the wired section Iub and the maximum transmittable rate of the wireless section Uu. The flow control unit 19 includes a means for setting, and the flow control unit 19 has a maximum allowable transmission rate set by the call processing unit 14 equal to or less than a maximum transmission possible rate based on the transmission capability of the mobile station 1 and a wired section. I b When the bandwidth utilization thresholds below, and a means for notifying the update request maximum allowable transmission rate of the wired section Iub to the call processing section 14.

  The flow control method of the present invention is a flow control method in a mobile communication system including a base station 2 that communicates with a mobile station 1 via a radio section Uu and communicates with a base station control station 3 via a wired section Uu. In this case, at the time of call setting, the smaller of the transmission possible rate according to the band usage status of the wired section Iub and the transmission possible rate of the wireless section Uu is set as the maximum allowable transmission rate of the wired section Iub and the base station The control station 3 is notified, the maximum allowable transmission rate of the set wired section Iub is set as the upper limit, the transmission possible rate of the wired section Iub is updated, and the base station control station 3 is notified, and the maximum allowable transmission rate is the mobile station 1 The maximum allowable transmission rate of the wired section Iub is updated and set when the band transmission rate of the wired section Iub is equal to or lower than the threshold, and the maximum transmission possible rate based on the transmission capability of It is intended to include a process of notifying the Chikyoku control station 3.

  FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention, where 1 is a mobile station (MS), 2 is a base station (BTS), 3 is a base station control station (RNC), 11 is a radio unit, and 12 is mobile The station corresponding unit, 13 is a line processing unit, 14 is a call control unit, 15 is a database, 16 is a line monitoring unit, 17 is a buffer, 18 is a signal processing unit, and 19 is a flow control unit. Iub represents a wired section between the base station 2 and the base station control station 3, and Uu represents a wireless section between the base station 2 and the mobile station 1.

  The radio unit 11 of the base station 2 has a function of performing transmission / reception processing including functions of modulation and demodulation of user data and control information in the radio section Uu between the base station 2 and the mobile station 1 The correspondence unit 12 has a configuration including a line processing unit 16, a buffer 17, a signal processing unit 18, and a flow control unit 19. The line processing unit 16, the buffer 17, and the signal processing unit 18 are connected to the mobile station 1 side. However, it also includes means for transferring user data from the mobile station 1 side to the base station control station 3 side, and the configuration thereof is not shown. is doing. Further, the line processing unit 13 obtains the function of transmitting / receiving user data and control information to / from the base station control station 3 via the wired section Iub, and notifies the call processing section 14 of the bandwidth usage rate of the wired section Iub. Functions.

  Also, the flow control unit 19 is based on the transmission quality information of the wireless section Uu with the mobile station 1 and the transmission quality information of the wired section Iub with the base station control station 3 at predetermined intervals or at predetermined intervals. When the above condition is satisfied, the transmission rate is connected to the base station control station 3 according to the function of transferring the MAX rate update request to the call processing unit 14 and the notification of the initial setting and update setting of the MAX rate from the call processing unit 14. And a function of notifying through the processing unit 13. Further, the database 15 stores, for example, transmission rate update width data corresponding to each priority when priority is set for a plurality of transmission data. Further, the call processing unit 14 has a function of performing a MAX rate update process or the like by referring to the database 15 based on the information on the wired section Iub band usage rate with the base station control station 3 and the MAX rate update request. It is what you have.

  At the time of call setup when the HSDPA method is applied, the call processing unit 14 compares the transmittable rate determined from the wired section Iub band usage rate and the maximum transmittable rate of the wireless section Uu depending on the transmission capability of the mobile station 1. Then, the smaller transmission rate is notified as the maximum allowable transmission rate (MAX rate) to the base station control station 3 by a CA (Capacity Allocation) signal. Then, the flow control unit 19 obtains a transmittable rate with this MAX rate as an upper limit during call connection, and notifies the base station control station 3 of the changed transmittable rate by a CA signal. The MAX rate obtained at the time of call setup becomes low when the wired section Iub band usage rate is high due to the large number of mobile stations accommodated in the base station 1. Therefore, the MAX rate at the time of initial setup is the mobile station 1. There are cases where the maximum possible rate determined by the transmission capability is less than the maximum possible rate. Therefore, the transmission quality of the wired section Iub and the wireless section Uu becomes better with the passage of time from the situation at the time of initial setting, and the transmittable rate notified to the base station control station 3 is the transmittable rate of the mobile station 1. When the lower initial setting MAX rate is reached and the duration for which the recalculable transmission rate becomes the MAX rate continues for a predetermined time, the flow control unit 19 issues a MAX rate update request to the call processing unit 14.

  In response to the MAX rate update request from the flow control unit 19, the call processing unit 14 collects the band usage rate of the wired section Iub at that time from the line processing unit 13. If the bandwidth usage rate is below a certain threshold, it is determined that the bandwidth can be updated, and the MAX rate is calculated again from the bandwidth usage rate at the time when the update request is received by the same process as that for call setup. Is notified of the update of the MAX rate. In this case, if the bandwidth usage rate is equal to or higher than a certain threshold, the update request is rejected. Further, when updating the MAX rate, the call processing unit 14 refers to the database 15 that defines the update width of the maximum allowable transmission rate of the wired section Iub for each priority of transmission data, and corresponds to the corresponding priority. The MAX rate is updated with the update width. In this case, the update width can be set to a large value for high-priority transmission data, and conversely, the update width can be reduced to data having low priority.

  The flow control unit 19 resets the updated MAX rate as the upper limit value of the flow control, and performs the subsequent flow control. The transmission possible rate according to the transmission quality status of the wireless section Uu and the wired section Iub is periodically calculated and notified to the base station control station 3 by a CA (Capacity Allocation) signal. When a plurality of MAX rate update requests from the flow control unit 19 to the call processing unit 14 are generated at the same time, the update is performed according to the priority of the corresponding transmission data. If all the transmission requests have the same priority and all the update requests are executed, if the bandwidth usage rate of the wired section Iub falls below a certain threshold, the update is performed for all the corresponding update requests. To implement. When all the update requests are executed, if the bandwidth usage rate of the wired section Iub is equal to or greater than a certain threshold value, the update process is performed for the update request within a range that is within the threshold value. If there is a difference in the priority of the transmission data, the update is preferentially performed for the update request corresponding to the transmission data having a high priority.

  FIG. 2 shows a sequence chart between the base station (BTS) 2 and the base station control station (RNC) 3 according to the first embodiment of the present invention. The base station 2 receives the HSDPA from the base station control station 3. When the system call setup notification is received, the MAX rate is calculated from the transmission capability of the mobile station (MS) 1 and the band usage status of the wired section Iub, and the HSDPA call setup response including this MAX rate is sent to the base station control station 3. Send to. The base station control station 3 performs transmission control using the initial transmission rate of user data for the mobile station 1 as the MAX rate. The base station 2 notifies the base station control station 3 by a CA (Capacity Allocation) signal when the MAX rate is updated due to the quality variation in the wireless / wired section. The base station control station 3 performs user data transmission processing according to the transmission rate notified from the base station 2. As a result, the MAX rate at the initial stage of call setup can be updated so as to increase in accordance with the capability of the mobile station 1 when it can be increased due to the improvement of the transmission status. That is, when the transmission state at the time of call setup improves, update setting for increasing the MAX rate according to the transmission capability of the mobile station can be performed.

3 and 4 show a flowchart of the first embodiment of the present invention, (A) is an explanation of abbreviations used in the flowchart, and (B) is a step (b1) of a flow control method including a change in transmission rate. ) To (b17). After the call is set, it is determined whether or not the maximum allowable transmission rate update period T has elapsed (b1). If the period has elapsed, the average bandwidth usage rate Z = X in the wired section (Iub section) is determined in the call processing unit 14. / Y is obtained (b2). X represents the average occupied bandwidth of the wired section (Iub) during the elapse of time T from the previous update, and Y represents the occupied bandwidth of the wired section (Iub) allowed for the HSDPA call. Then, it is determined whether Z <Z _th (b3). If the average bandwidth utilization Z is the threshold Z _th smaller, the process proceeds to step (b1), step (b2), performs processing (b3), if also large, moving the maximum allowable transmission rate set The number of mobile stations in the call connection that are less than the capacity of the station (MS) 1 is confirmed (b4), and X _temp = X is set (b5). Let N _{P1 be} the number of mobile stations with priority P1 at which this maximum allowable transmission rate is set below the capacity of the mobile station, and N _P2 be the number of mobile stations with priority P2 (> P1). It should be noted that the priorities can be more various.

Next, it is determined whether N _P2 ≠ 0 (b6) (see FIG. 4). If the number of mobile stations with the priority P2 is 0, the process proceeds to step (b12). If the number of mobile stations with the priority P2 is not 0, the priority with which the maximum allowable transmission rate is less than the capability of the mobile station. A wired section (Iub) occupation band when the maximum allowable transmission rate is updated for one mobile station among the mobile stations of _{P2 is} calculated by _Xtemp = _Xtemp + ΔXP2 (b7). Then, it is determined whether (X _temp / Y) <Z _th (b8). If this determination condition is not satisfied, the process proceeds to step (b1). If the determination condition is satisfied, the maximum allowable transmission rate is set to ΔX for the mobile station having the priority P2 assumed in step (b7). _{P2 is} increased (b9), and the number of mobile stations with priority P2 is set to N _P2 = N _P2 −1 (b10). Then, it is determined whether _NP2 is 0 (b11). If it is not 0, the process proceeds to step (b7), and the above steps (b7) to (b11) are repeated. Go to b12).

In step (b12), it is determined whether or not the number of mobile stations NP1 with priority P1 is 0. If it is 0, the process proceeds to step (b1). If it is not 0, the maximum allowable transmission rate is shifted. The wired section (Iub) occupied band when the maximum allowable transmission rate is updated for one mobile station of the priority P1 which is less than the station capacity is X _temp = X _temp + ΔX _P1 (B14). Then, it is determined whether (X _temp / Y) <Z _th (b8). If the determination condition is not satisfied, the process proceeds to step (b1). If the determination condition is satisfied, the maximum allowable transmission rate of the mobile station having the priority P1 assumed in step (b13) is increased by ΔX _P1 (b15 ), The number of mobile stations with the priority P1 is set to N _P1 = N _P1 −1 (b16).

Then, it is determined whether or not the number of mobile stations NP1 with priority _P1 is 0 (b17). If not, the process proceeds to step (b13), and the above steps (b13) to (b17) are repeated. In the case of 0, the process proceeds to step (b1). Thereafter, in steps (b1) to (b17), the MAX rate at the time of call setting is increased based on the transmission capability and transmission status of the mobile station, and if it can be increased, setting change processing is performed to increase transmission as a whole system. Efficiency can be improved. Further, the update widths ΔX _P1 and ΔX _P2 of the maximum allowable transmission rate can be set in the database 15 shown in FIG. 1 so as to correspond to the priorities P1 and P2.

It is explanatory drawing of Example 1 of this invention. It is a sequence chart of Example 1 of this invention. It is a flowchart of Example 1 of this invention. It is a flowchart of Example 1 of this invention. It is explanatory drawing of a mobile radio system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile station 2 Base station 3 Base station control station 11 Radio | wireless part 12 Mobile station corresponding | compatible part 13 Line processing part 14 Call processing part 15 Database 16 Line monitoring part 17 Buffer 18 Signal processing part 19 Flow control

Claims (5)

In a mobile communication system including a base station that communicates with a mobile station via a wireless section and communicates with a base station control station via a wired section,
The base station includes a radio unit that performs radio transmission / reception via the radio zone, a line processing unit that transmits / receives via the wired zone, a call processing unit, and a flow control unit, and The processing unit obtains a maximum allowable transmission rate of the wired section based on the transmittable rate obtained based on the band usage rate of the wired section and the maximum transmittable rate of the wireless section, and sets the maximum allowable transmission rate in the flow control unit. The flow control unit includes a maximum allowable transmission rate set by the call processing unit equal to or lower than a maximum transmittable rate based on a transmission capability of the mobile station, and a bandwidth usage rate of the wired section is equal to or lower than a threshold value. A mobile communication system comprising means for notifying the call processing unit of an update request for the maximum allowable transmission rate of the wired section.   The base station includes a database storing update widths corresponding to a plurality of types of priorities of transmission data referred to by the call processing unit that performs update processing according to an update request for a maximum allowable transmission rate from the flow control unit. The mobile communication system according to claim 1. In a flow control method in a mobile communication system including a base station that communicates with a mobile station via a wireless section and communicates with a base station control station via a wired section,
At the time of call setup, a smaller one of the transmittable rate according to the band usage status of the wired section and the transmittable rate of the wireless section is set as the maximum allowable transmission rate of the wired section and notified to the base station control station Then, with the maximum allowable transmission rate of the set wired section as an upper limit, the transmission possible rate of the wired section is updated and notified to the base station control station, and the maximum allowable transmission rate is based on the transmission capability of the mobile station Including a step of updating and setting the maximum allowable transmission rate of the wired section and notifying the base station control station when the bandwidth usage rate of the wired section is equal to or lower than a threshold value when the bandwidth is less than a maximum transmittable rate. Flow control method.   4. The flow control method according to claim 3, further comprising a step of updating the maximum allowable transmission rate of the wired section according to an update width corresponding to a priority of transmission data.   Including a step of preferentially updating the maximum permissible transmission rate for transmission data having a high priority when there are a plurality of update target mobile stations for the maximum permissible transmission rate in the wired section and the priority of transmission data is different. The flow control method according to claim 3, wherein:

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