Abstract:
A method for improving user-interactive data QoS and system thereof, the method comprises: Adjusting the transmission rate of each user, by means of the corresponding reverse inter-user QoS parameters attribute such as reverse probability transfer matrix and/or maximum rate limit or the like, which are set for the users with different QoS levels, and thus allowing the users with different QoS levels to enjoy different maximum reverse rate and average reverse rate, so as to achieve the purpose that improve the user-interactive reverse data QoS. The invention not only satisfies the requirements of different terminal user, but also provides the QoS solution of graduating charge service for network operator, and improves the operating profit while satisfying the requirements of various users.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to the field of communication, and particularly to a method and a system for improving QoS of user interactive data.  
       BACKGROUND OF THE INVENTION  
       [0002]     At present, many communication systems support high-speed transmission of wireless data services, such as CDMA (Code Division Multiple Access) 2000 1xEV-DO (Evolution Data Only) system. During high-speed transmission of a data service, for a single user, the maximum rate of forward transmission that can be reached is 2.4 Mbps, and the maximum rate of reverse transmission that can be reached by a user is 153.6 kbps. However, the CDMA2000 system is a elf-interference system with limited capacity. When the forward transmission is performed, multiple users using the same sector carrier share and compete for the forward bandwidth of 2.4 Mbps. When the reverse transmission is performed, because the total bandwidth of a sector carrier is only 400 k, if the number of users is large, the reverse load will rise, which leads to competition between the users and power increasing. Hence, both the total throughput of the sector and the throughput of each user will be reduced, and the Quality of Service QoS) for the users cannot be ensured.  
         [0003]     From the purpose of the users employing wireless data service transmission, the demands of the users are hierarchical. The demands of some users are not very high. For example, chatting on QQ demands a very low rate, sending e-mails demands a higher rate than the rate of QQ but does not necessarily has demand unreal-time and real-time wireless video service, demands a very high rate. Therefore, and operator needs to have the ability to provide hierarchical inter-user QoS service to meet the various user demands. While satisfying the demands of users, the operator can also improves operating outcome by charging according to levels, for example, the highest rate is provided for a VIP; a middle rate is provided for a high-level user; and a basic rate is provided for a common user.  
         [0004]     The prior art provides a technical solution for implementing forward intenser QoS as follows.  
         [0005]     The forward channel of CDMA2000 1xEV-DO is a time-division system, in which an Access Network (AN) provides a real-time scheduling module for deciding when and for how long each user will obtain the service according to some factors such as requested rate, historical throughput and user function. Shares of the service obtained by different users can be adjusted in real time by means of the user function The higher the level of the user is, the larger the share is, the more the chances to be scheduled can be obtained, and the higher the rate is.  
         [0006]     In the prior art, only forward inter-user QoS can be realized. The priority or level of a user can not be considered in the reverse direction, e.g., corresponding reverse highest rates and reverse average rates cannot be provided for users of different levels. So, in the reverse direction, when the users are not many and the system capacity has not been saturated, the service demand of each user can be satisfied; once the reverse load is relatively high, competition will occur among the users, leading to a widely decreasing of the reverse rate of each user. The users closer to the base station are more competitive than that far away from the base station, but the high-speed service demands of some users cannot be satisfied.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides a method and a system for improving the QoS of user interactive data, which is able to provide corresponding reverse highest rates and reverse average rates for users of different QoS levels.  
         [0008]     The present invention provides a method for improving the QoS of user interactive data including:  
         [0009]     A. setting attribute parameters of a reverse inter-user QoS level for a user according to the QoS level of the user;  
         [0010]     B. adjusting the transmission rate of the user based on the attribute parameters of the reverse inter-user QoS level.  
         [0011]     In an embodiment of the present invention the step A includes:  
         [0012]     A1. setting an attribute parameter of maximum rate limit for the user and setting a corresponding attribute parameter of reverse transition probability matrix for the user according to the QoS level of the user; or,  
         [0013]     A2. setting an attribute parameter of reverse transition probability matrix for the user, and setting a corresponding attribute parameter of reverse maximum rate limit for the user according to the QoS level of the user and the current reverse load level; or,  
         [0014]     A3. setting a corresponding attribute parameter of reverse transition probability matrix for the user according to the QoS level of the uses and setting a corresponding attribute parameter of reverse maximum rate limit for the user according to the QoS level of the user and the current reverse load level; or,  
         [0015]     A4. setting an attribute parameter of reverse transition probability matrix for the user, and setting an attribute parameter of corresponding reverse maximum rate limit for the user according to the QoS level of the user.  
         [0016]     In an embodiment of the present invention the process of setting a corresponding attribute parameter of reverse transition probability matrix for the user according to the QoS level of the user includes:  
         [0017]     setting, by an Access Network, a high attribute parameter of transition probability matrix for a user of high QoS level, and setting a low attribute parameter of transition probability matrix for a user of lowQoS level.  
         [0018]     In an embodiment of the present invention the process of setting an attribute parameter of reverse maximum rate limit corresponding to the user&#39;s QoS level for the user includes:  
         [0019]     setting a high attribute parameter of reverse maximum rate limit for a user of high QoS level, and setting a low attribute parameter of reverse maximum rate limit for a user of low QoS level.  
         [0020]     In an embodiment of the present invention the process of setting a corresponding attribute parameter of reverse maximum rate limit for the use is according to the QoS level of the user and the current reverse load level includes:  
         [0021]     determining the reverse load level of the system according to the total noise received on the reverse direction;  
         [0022]     according to the load level and the QoS level of the user, setting a high attribute parameter of reverse maximum rate limit for a user of highQoS level, and setting a low attribute parameter of reverse maximum rate limit for a user of low QoS level.  
         [0023]     In an embodiment of the present invention the step B includes:  
         [0024]     B1. obtaining, by the Access Network, the attribute parameter of reverse inter user QoS level corresponding to the QoS level subscribed by the user;  
         [0025]     B2. adjusting the transmission rate of a user of each QoS level based on the attribute parameter  
         [0026]     In an embodiment of the present invention the step B1 includes:  
         [0027]     B11. accessing, by the uses the system by a connection request message in which the identity information of the user is carried;  
         [0028]     B12. querying, by the Access Network, the QoS level subscribed by the user in account information of the AT according to the identity information, and obtaining the corresponding attribute parameters of reverse transition probability matrix and/or maximum rate limit according to the QoS level.  
         [0029]     In an embodiment of the present invention the step B2 includes:  
         [0030]     B21. notifying, by the Access Network, the user to update the transition probability matrix by negotiating an attribute parameter of rate, and updating the reverse maximum rate limit of the user using the attribute parameter of maximum rate limit set for the user by transmitting a reverse rate limit message;  
         [0031]     B22. determining whether the load on the reverse traffic channel is overloaded according to the total noise received on the reverse direction, if Yes, transmitting a Reverse Activity Bit characterized as overloaded to the user and then performing step B23; otherwise, transmitting a Reverse Activity Bit characterized as not overloaded to the user, and then performing step B23;  
         [0032]     B23. receiving, by the user, the Reverse Activity Bit, and adjusting the transmission rate of the reverse channel according to the characteristic of the Reverse Activity Bit and updated attribute parameters of transition probability matrix and/or maximum rate limit.  
         [0033]     In an embodiment of the present invention the step B23 includes:  
         [0034]     B231. receiving, by the user, the Reverse Activity Bit, and determining whether the reverse load is overloaded according to the characteristic of the Reverse Activity Bit, if Yes, step B232 is performed; otherwise, step B233 is performed;  
         [0035]     B232. reducing the reverse transmission rate according to the updated attribute parameters of reverse maximum rate limit and/or transition probability matrix;  
         [0036]     B233. improving the reverse transmission rate according to the updated attribute parameters of reverse maximum rate limit and/or transition probability matrix.  
         [0037]     In an embodiment of the present invention the step B232 includes:  
         [0038]     B2321. selecting, by the user, an attribute parameter of transition probability according to current transmission rate of the AT;  
         [0039]     B2322. comparing, by the Access Terminal, a random number it generated with the selected attribute parameter of transition probability if the random number is less than transition probability then reducing its current rate to the transmission rate of the next lower grade described in the attribute parameter of transition probability matrix; otherwise, keeping the original rate; or,  
         [0040]     B2323. reducing, by the user, the reverse transmission rate within the range permitted by the updated maximum rate limit according to the updated attribute parameter of reverse transition probability matrix.  
         [0041]     In an embodiment of the present invention the step B233 includes:  
         [0042]     B2331. selecting, by the user, an attribute parameter of transition probability for its Access Terminal according to its current transmission rate;  
         [0043]     B2332. comparing, by the AT, a random number it generated with the selected transition probability if the random number is less than the transition probability then improving its current rate to the transmission rate of the next upper grade described in the attribute parameter of transition probability matrix within the range permitted by the maximum rate limit; otherwise, keeping the original rate; or,  
         [0044]     B2333. improving, by the user, the reverse transmission rate within the range permitted by the updated maximum rate limit according to the updated attribute parameter of reverse transition probability matrix.  
         [0045]     In another aspect of the present invention, the present invention also provides a method for improving the QoS of user interactive data, including:  
         [0046]     1) obtaining, by a user, an attribute parameter of reverse inter user QoS level corresponding to the QoS level subscribed by the user from the Access Network when the user AT accesses the system by a connection request message;  
         [0047]     2) based on the information regarding whether the reverse load is overloaded, the user terminal adjusting the reverse transmission rate according to the attribute parameter of reverse inter-user QoS level.  
         [0048]     The step 1) includes:  
         [0049]     11) accessing, by the uses the system by the connection request message in which the identity information of the user is carried;  
         [0050]     12) querying, by the Access Network, the QoS level subscribed by the user in account information of the AT according to the identity information, and obtaining the corresponding attribute parameters of reverse transition probability matrix and/or maximum rate limit according to the QoS level;  
         [0051]     13) notifying, by the Access Network, the user to update the transition probability matrix by negotiating the attribute parameter of rate, and updating the reverse maximum rate limit of the user using the attribute parameter of maximum rate limit set for the user by transmitting a reverse rate limit message.  
         [0052]     The step 2) includes:  
         [0053]     21) determining, by the Access Network, whether the load on the reverse traffic channel is overloaded according to the total noise received on the reverse direction, if Yes, transmitting a Reverse Activity Bit characterized as overloaded to the user and then performing step 22); otherwise, transmitting a Reverse Activity Bit characterized as not overloaded to the uses and then performing step 22);  
         [0054]     22) receiving, by the uses the Reverse Activity Bit, and adjusting the reverse transmission rate according to the characteristic of the Reverse Activity Bit and the updated attribute parameters of transition probability matrix and/or maximum rate limit.  
         [0055]     In another aspect of the present invention, the present invention also provides a system for improving the QoS of user interactive data, including a user AT and an Access Network; in which,  
         [0056]     attribute parameters of reverse inter-user QoS level corresponding to the QoS level subscribed by the user is configured in the Access Network;  
         [0057]     when accessing the system by a connection request message, the user terminal obtains the attribute parameters of reverse inter-user QoS level corresponding to the QoS level subscribed by the user from the Access Network; based on the information regarding whether the reverse load is overloaded obtained from the Access Network, adjusts the transmission rate of the reverse channel according to the attribute parameters of reverse inter-user QoS level.  
         [0058]     It can be seen from the technical solution of the present invention that the reverse transmission rate of the user is adjusted based on the attribute parameters of reverse inter-user QoS set for users of different QoS levels, so that the users of different levels enjoy different reverse highest rates and reverse average rates. Therefore the QoS of the user interactive data is improved, and the problem that corresponding reverse highest rates and reverse average rates for the users of different QoS levels cannot be provided the prior art is solved. The present invention can not only meet the demands of different terminal users, but also provide a QoS solution of hierarchical charging service for network operators, satisfying different user demands and improving operating income at the same time. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0059]      FIG. 1  is a flow diagram illustrating a first embodiment of the present invention;  
         [0060]      FIG. 2  is a flow diagram illustrating a second embodiment of the present invention;  
         [0061]      FIG. 3  is a flow diagram illustrating a third embodiment of the present invention;  
         [0062]      FIG. 4  is a flow diagram illustrating a fourth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0063]     The present invention provides a method for improving the QoS of the user interactive data, including adjusting the transmission rate of the users by setting corresponding reverse attribute parameters of inter-user QoS such as reverse transition probability matrix and/or maximum rate limit etc. for users of different QoS levels, thereby the object of improving the QoS of the user reverse data is achieved.  
         [0064]     QoS levels of users are generally partitioned by operators according to the demands of their service operating. For example, the users can be divided into three classes according to the QoS levels: VIP users, high-priority users and common users. Of course the classification is not limited to this. A user registers the QoS level he/she demands when the account of the AT is established.  
         [0065]     Take the above-mentioned classification result for example, as shown in  FIG. 1 , a first embodiment provided by the present invention includes:  
         [0066]     Block S 101 , a reverse maximum rate limit is set for the user and a corresponding attribute parameter of reverse transition probability matrix is set for the user according to the QoS level of the user.  
         [0067]     For the reverse transmission rate, possible rate levels are 9.6 kbps, 19.2 kbps, 38.4 kbps, 76.8 kbps and 153.6 kbps.  
         [0068]     Considering the possible rate levels, when the corresponding attribute parameter of maximum rate limit is set for the user it can be set either to all the users in a system uniformly or to each user in the system respectively  
         [0069]     Considering the possible rate levels, when setting the corresponding attribute parameter of reverse transition probability matrix for the user, possible transition probabilities are shown in Table 1.  
                       TABLE 1                                       Transition009k6_019k2           Transition019k2_038k4           Transition038k4_076k8           Transition076k8_153k6           Transition019k2_009k6           Transition038k4_019k2           Transition076k8_038k4           Transition153k6_076k8                      
 
         [0070]     Each attribute parameter in Table 1 is larger than 0 and less than 1, and from the representation of each attribute parameter it can be seen that two rate levels are identified in each attribute parameter For example, 0&lt;Transition038k4 — 019k2&lt;1, the two rate levels identified in this attribute parameter are respectively 19.2 kbps and 38.4 kbps. The transition probability matrix may configured for each AT (Access Terminal).  
         [0071]     For example, when dividing the users into VIP users, high-priority users and common users according to the above-mentioned QoS levels of the users, the attribute parameters of transition probability matrix set for respective levels are shown in Table 2:  
                                                 TABLE 2                                       high-priority               VIP users   users   Common users                                    Transition009k6_019k2   Y11   Y12   Y13       Transition019k2_038k4   Y21   Y22   Y33       Transition038k4_076k8   Y31   Y32   Y33       Transition076k8_153k6   Y41   Y42   Y43       Transition019k2_009k6   Y51   Y52   Y53       Transition038k4_019k2   Y61   Y62   Y63       Transition076k8_038k4   Y71   Y72   Y73       Transition153k6_076k8   Y81   Y82   Y83                  
 
         [0072]     All the data in this table satisfy: 
        1. Y i1 ≧Y i2 ≧Y i3 , Y ij ε[0,1], j=1, 2, 3; i=1˜4     2. Y i1 ≦Y i2 ≦Y i3 , Y ij ε[0,1], j=1, 2, 3; i=5˜8        
 
         [0075]     From the above-mentioned setting, it can be seen that according to the QoS levels of the users, the AN sets a high attribute parameter of transition probability matrix for a user of high QoS level, and sets a low attribute parameter of transition probability matrix for a user of low QoS level.  
         [0076]     In block S 102  of  FIG. 1 , the user accesses the system by a connection request message which carries the identity information of the user.  
         [0077]     In block S 103 , the AN queries the QoS level subscribed by the user in account information of the AT according to the identity information; and obtains the corresponding attribute parameter of transition probability matrix according to the QoS level.  
         [0078]     After the above process, the AN is able to adjust the transmission rate of the user of each QoS level based on the attribute parameter thereby the QoS of the user interactive reverse data is improved.  
         [0079]     Block S 104 , the AN notifies the user to update the transition probability matrix by negotiating the attribute parameter of rate, such as RateParameterAttribute, and updates the reverse maximum rate limit using the attribute parameter of maximum rate limit set for the user by transmitting a the reverse rate limit message, such as ReverseRateLimit.  
         [0080]     Block S 105 , the AN determines whether the load on the reverse traffic channel is overloaded according to the total noise received on the reverse channel, if Ys, block S 106  is performed, the AN transmits an indication, such as Reverse Activity Bit characterized as overloaded to the Access Terminal of the user, and then block S 108  is performed; otherwise, block S 107  is performed, the AN transmits the Reverse Activity Bit characterized as not overloaded to the user, and then block S 108  is performed.  
         [0081]     During block S 105 , on determining whether the reverse traffic channel is overloaded according to the total noise received on the reverse direction, the AN transmits the information regarding whether the reverse traffic channel is overloaded to the AT of the user by transmitting an indication, such as Reverse Activity Bit RA, where ‘RA=1’ represents overloaded and ‘RA=0’ represents not overloaded.  
         [0082]     The RA bit transmitted by the AN is identical to all the ATs in one sector carrier  
         [0083]     Block S 108 , the user receives the Reverse Activity Bit, and determines whether the reverse traffic channel is overloaded according to the characteristic of the Reverse Activity Bit, if Yes, block S 109  is performed; otherwise, block S 110  is performed.  
         [0084]     The AT demodulates the RA, if the load is overloaded, it indicates that the rate should be reduced by a certain probability; if the load is not overloaded, it indicates that the rate should be increased by a certain probability. The RA bit is identical for all the users in one system, but not all of the ATs increase the rates or reduce the rates simultaneously after the AT receive the RA bit, while each AT determines whether to increase the rate or reduce the rate finally according to the transition probability matrix  
         [0085]     Block S 109 , reducing the reverse transmission rate according to the updated attribute parameter of transition probability matrix. The specific implementation process may be:  
         [0086]     Firstly, the AT selects an attribute parameter of transition probability according to the current transmission rate.  
         [0087]     Then, the AT compares a random number it generated with the selected attribute parameter of transition probability if the random number is less than the transition probability, the AT reduces the current rate to the transmission rate of the next lower grade described in the attribute parameter of transition probability matrix otherwise, keeps the original rate.  
         [0088]     Block S 110 , improving the reverse transmission rate within the range permitted by the maximum rate limit according to the updated attribute parameter of reverse transition probability matrix. The specific implementation process may be:  
         [0089]     At first, the AT selects an attribute parameter of transition probability according to the current transmission rate;  
         [0090]     Then the AT compares a random number it generated with the selected attribute parameter of transition probability if the random numbs is less than the transition probability, the AT increases its current rate to the transmission rate of the next higher grade described in the attribute parameter of transition probability matrix within the range permitted by the maximum rate limit; otherwise, keeps the original rate.  
         [0091]     Now blocks S 109  and S 110  will be described in detail still taking the attribute parameters in Table 1 for example:  
         [0092]     Assuming the current rate of the AT is 38.4 kbps, the attribute parameter of transition probability is selected as Tansition038k4 — 019k2.  
         [0093]     When the AT demodulates the RAbit and finds that the bit indicates reducing the rate, the AT will generate a random number x, and 0≦x≦1; when x&lt;Transition038k4 — 019k2, the rate of the X is reduced from 38.4 kbps to 19.2 bps, otherwise, the original rate is kept.  
         [0094]     When the AT demodulates the RA bit and finds that it indicates increasing the rate, the AT will generate a random number x, and 0≦x≦1; when x&lt;Transition038k4 — 076k8, the rate of the X is improved from 38.4 kbps to 76.8 kbps within the range permitted by the maximum rate limit, otherwise, the original rate is kept.  
         [0095]     As shown in  FIG. 2 , an embodiment provided by the present invention includes:  
         [0096]     Block S 201 , a reverse transition probability matrix is set for the user and a corresponding reverse maximum rate limit is set according to the current reverse load level and the QoS level of the user.  
         [0097]     The maximum reverse rate of the AT may not exceed the maximum rate limit (Ratelimit). According to possible rate grades of the reverse transmission rate: 9.6 kbps, 19.2 kbps, 38.4 kbps, 78.6 kbps and 153.6 kbps, the Rate limit of the AT is divided into five grades: 9.6 kbps, 19.2 kbps, 38.4 kbps, 78.6 kbps and 153.6 kbps.  
         [0098]     The AN sets a corresponding attribute parameter of transition probability matrix for each user according to the above-mentioned possible rate grades of the reverse transmission rate.  
         [0099]     The process of the AN setting the corresponding maximum rate limit according to the QoS level of the user and the current reverse load level is:  
         [0100]     Step  1 , according to the QoS level of the uses the AN sets a high current reverse maximum rate limit for a user of a highQoS level, and sets a low current reverse maximum rate limit for a user of a lowQoS level;  
         [0101]     Step  2 , the AN determines the reverse load level of the system according to the total noise received on the reverse direction, and based on the load level, sets the corresponding reverse maximum rate limit according to the QoS level of the user  
         [0102]     The AN determines the reverse load level according to the total noise received on the reverse direction. Here assuming the reverse load is divided into 3 grades, e.g. high-load status, middle-load status and low-load status. Two thresholds, NoiseThresh 1  and NoiseThresh 2  are set.  
         [0103]     If the total reverse noise&lt;NoiseThresh 1 , the AN considers that the system is in the low-load status; where the AN sets the maximum rate limit of each user according to the bandwidth of the system: sets a high reverse maximum rate limit for the a user of a high QoS level, and sets a low reverse maximum rate limit for a user of a lowQoS level;  
         [0104]     if NoiseThresh 1 &lt;=the total reverse noise&lt;NoiseThresh 2 , the AN considers that the system is in the middle-load status; where the AN keeps the current maximum rate limit set for the user of the highQoS level and keeps the current maximum rate limits set for the user of the lowQoS level;  
         [0105]     if NoiseThresh 2 &lt;=the total reverse noise, the AN considers that the system is in the high-load status; where the AN sets a reverse maximum rate limit lower than the current maximum rate limit by one grade for the user of the highQoS level, and sets a reverse maximum rate limit lower than the current maximum rate limit by one grade for the user of the lowQoS level.  
         [0106]     Still take example for dividing the users into VIPusers, high-priority users and common users according to the QoS levels of the users as mentioned above, the result of setting the Rate limit for the users of each level by the AN are shown in Table 3:  
                                                 TABLE 3                                       High-priority               VIP users   users   Common users                                    Reverse low-load status   X11   X12   X13       Reverse middle-load status   X21   X22   X23       Reverse high-load status   X31   X32   X33                  
 
         [0107]     where all the data in this table satisfy the following demands: 
        1. X ij ε[9.6 kbps,153.6 kbps],i/j=1,2,3     2. X i1 ≧X i2 ≧X i3 ,X ij ε=[9.6 kbps,153.6 kbps],i/j=1,2,3, and     3. X 1j ≧X 2j ≧X 3j ,i/j=1,2,3        
 
         [0111]     Block S 202 , the user accesses the system by a connection request message in which the identity information of the user is carried.  
         [0112]     Block S 203 , the AN queries the QoS level subscribed by the user in account information of the AT according to the identity information; and obtains the corresponding attribute parameter of reverse maximum rate limit according to the QoS level.  
         [0113]     Block  204 , updating the reverse maximum rate limit of the user by transmitting a ReverseRateLimit (reverse rate limit) message; the user is notified to update the current attribute parameter of reverse transition probability matrix using the attribute parameter of reverse transition probability matrix set for the user by negotiating RateParameterAttribute.  
         [0114]     Block S 205 , the Access Network determines whether the reverse traffic channel is overloaded according to the total noise received on the reverse direction if Yes, block S 206  is performed, a Reverse Activity Bit characterized as overloaded is transmitted to the Access Terminal, and then block S 208  is performed; otherwise, block S 207  is performed, a Reverse Activity Bit characterized as not overloaded is transmitted to the user, and then block S 208  is performed.  
         [0115]     Block S 208 , the user receives the Reverse Activity Bit, and determines whether the reverse traffic channel is overloaded according to the characteristic of the Reverse Activity Bit, if Yes, block S 209  is performed; otherwise, block S 210  is performed.  
         [0116]     Block S 209 , according to the updated attribute parameter of reverse transition probability matrix, the transmission rate of the reverse channel is reduced within the range permitted by the updated maximum rate limit.  
         [0117]     Block S 210 , according to the updated attribute parameter of reverse transition probability matrix, the transmission rate of the reverse channel is increased within the range permitted by the updated maximum rate limit.  
         [0118]     As shown in  FIG. 3 , the third embodiment provided by the present invention includes:  
         [0119]     Block S 301 , a corresponding reverse transition probability matrix is set for the user according to the QoS level of the uses and a corresponding maximum rate limit is set according to the QoS level of the user and the current reverse load level.  
         [0120]     Referring to the detailed description of blocks S 101  and S 102  in an embodiment for the specific implementation process.  
         [0121]     Block S 302 , the user accesses the system by a connection request message, in which the identity information of the user is carried.  
         [0122]     Block S 303 , the AN queries the QoS level subscribed by the user in account information of the AT according to the identity information; and obtains the corresponding attribute parameters of reverse maximum rate limit, e.g. the attribute parameters of reverse transition probability matrix and maximum rate limit according to the QoS level.  
         [0123]     After the above-mentioned steps, the AN is able to adjust the transmission rates of users of each QoS levels based on the attribute parameters, thereby the QoS of the user interactive reverse data is improved.  
         [0124]     Block S 304 , the AN notifies the user to update the transition probability matrix by negotiating RateParametersAttribute; and updates the reverse maximum rate limit of the user by transmitting a ReverseRateLimit message.  
         [0125]     Block S 305 , the AN determines whether the reverse traffic channel is overloaded according to the total noise received on the reverse direction, if Yes, block S 306 , the AN transmits a Reverse Activity Bit characterized as overloaded to the Access Terminal, and then block S 308  is performed; otherwise, block S 307 , the AN transmits a Reverse Activity Bit characterized as not overloaded to the user and then block S 308  is performed.  
         [0126]     Block S 308 , the user receives the Reverse Activity Bit, and determines whether the reverse load is overloaded according to the characteristic of the Reverse Activity Bit, if Yes, block S 109  is performed; otherwise, block S 110  is performed.  
         [0127]     Block S 309 , the reverse transmission rate is reduced according to the updated attribute parameter of reverse transition probability matrix. The specific implementation process is:  
         [0128]     Firstly, the AT selects an attribute parameter of transition probability according to the current transmission rate.  
         [0129]     Then, the AT compares a random number it generated with the selected attribute parameter of transition probability if the random number is less than the transition probability, the AT reduces its current rate to the transmission rate of the next lower grade described in the attribute parameter of transition probability matrix otherwise, keeps the original rate.  
         [0130]     Block S 310 , the reverse transmission rate is increased according to the updated attribute parameters of reverse transition probability matrix and maximum rate limit. The specific implementation process is:  
         [0131]     At first, the AT selects an attribute parameter of transition probability according to the current transmission rate;  
         [0132]     then the AT compares a random number it generated with the selected attribute parameter of transition probability if the random number is less than the transition probability, the AT increases its current rate to the transmission rate of the next higher grade described in the attribute parameter of transition probability matrix within the range permitted by the maximum rate limit; otherwise, keeps the original rate.  
         [0133]     Assuming the current rate of the AT is 38.4 kbps, the attribute parameter of transition probability matrix is selected as Transition038k4 — 019k2.  
         [0134]     When the AT demodulates the RA bit and find it indicates reducing the rate, the AT will generate a random number x, and 0≦x≦1; when x&lt;Transition038k4 — 019k2, the rate of the AT is reduced from 38.4 kbps to 19.2 bps, otherwise, the original rate is kept.  
         [0135]     When the AT demodulates the RA bit and find that it indicates improving the rate, the AT will generate a random number x, and 0≦x≦1; when x&lt;Tansition038k4 — 076k8, the rate of the AT is improved from 38.4 kbps to 76.8 kbps within the range permitted by the maximum rate limit, otherwise, the original rate is kept.  
         [0136]     As shown in  FIG. 4 , the fourth embodiment provided by the present invention includes:  
         [0137]     Block S 401 , a reverse transition probability matrix is set for the user and a corresponding reverse maximum rate limit is set for the user according to the QoS level of the user.  
         [0138]     Take example for dividing the users into VIPusers, high-priority users and common users according to the QoS levels of the users as mentioned above, the attribute parameters of reverse maximum rate limit set for each user are shown in Table 4:  
                                                 TABLE 4                                       High-priority               VIP users   users   Common users                                    Reverse maximum rate   X1   X2   X3       limit                  
 
         [0139]     Block S 402 , the user accesses the system by a connection message, in which the identity information of the user is carried.  
         [0140]     Block S 403 , the AN queries the QoS level subscribed by the user in the account information according to identity information of the X; and obtains the corresponding attribute parameter of reverse maximum rate limit according to the QoS level.  
         [0141]     After the above-mentioned steps, the AN is able to adjust the transmission rates of the users of different QoS levels based on the attribute parameters, thereby the QoS of the user interactive reverse data is improved. The specific implementation process is:  
         [0142]     Block S 404 , the attribute parameter of reverse maximum rate limit is updated by a RerverseRateLimit message and the user is notified to update the attribute parameter of transition probability matrix by negotiating RateParametersAttribute.  
         [0143]     Block S 405 , the AN determines whether the reverse traffic channel is overloaded according to the total noise received on the reverse direction, if Yes, block S 406  is performed, a Reverse Activity Bit characterized as overloaded is transmitted to the Access Terminal and then block S 408  is performed; otherwise, block S 407 , a Reverse Activity Bit characterized as not overloaded is transmitted to the user and then block S 408  is performed.  
         [0144]     Block S 408 , the user receives the Reverse Activity Bit, and determines whether the reverse traffic channel is overloaded according to the characteristic of the Reverse Activity Bit, if Yes, block S 409  is performed; otherwise, block S 410  is performed.  
         [0145]     Block S 409 , according to the updated attribute parameter of reverse transition probability matrix, the reverse transmission rate channel is reduced within the range permitted by the maximum rate limit.  
         [0146]     Block S 410 , according to the updated attribute parameter of reverse transition probability matrix, the reverse transmission rate is increased within the range permitted by the maximum rate limit.  
         [0147]     By the implementation steps in the above-mentioned embodiments, for the users with activity connection using the same sector carrier:  
         [0148]     the average rate of the VIP user service≧the average rate of the high-priority user service≧the average rate of the common user service  
         [0149]     According to the present invention, if the QoS strategy of an operator is changed, the values of the “reverse inter-user QoS” attribute parameters can also be modified dynamically according to the demand, and the attribute parameters of maximum rate limit and transition probability matrix of the users demanding different service levels can also be adjusted. For example, when the operator wish to increase the QoS disparity between the users of different levels, the difference between the parameters of the users with different levels in Tables 1, 2 and 3 can be made bigger; on the contrary the difference between the parameters can be made less.  
         [0150]     It can be seen from the embodiments of the present invention, the invention is able to provide reverse inter-user QoS service for CDMA2000 1XEV-DO system, making the users with different levels enjoy different reverse highest rates and reverse average rates; in each reverse load statuses, different highest rates are set to facilitate the stability of the system; the present invention can satisfy demands of different users, the users with only low-rate demand may pay less fee and save the spending, while the users with high-rate demands may purchase high-rate services. Therefore, not only the satisfaction degree of the terminal users is improved, but also the service categories of the operator is enriched, by which the users are attracted by the operator and the operating income is obtained.  
         [0151]     It should be emphasized that the above-described embodiments, particularly any ‘preferred’ embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described preferred embodiment(s) without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the above-described preferred embodiment(s) and protected by the following claims.