Method system and a mobile communication station adapted for selection of an access network

Abstract

In a method of selecting an access network from among one or more access networks capable of providing service to a mobile communication station, a radio quality from the terminal to each access network is determined (S 1 ), for each access network, a utilization factor for at least one node is determining (S 2 ), for each access network, a user perceived data quality, based on said determined utilization factor and said determined radio quality for the access network, is determined (S 3 ), and at least one of said access networks, is selected (S 4 ) based on the determined user perceived quality, whereby an improved user perceived data quality is enabled.

1 . A method of selecting an access network from among one or more access networks capable of providing service to a mobile communication station, characterized by: 
 determining (S 1 ) a radio quality from the terminal to each access network,    determining (S 2 ), for each access network, a utilization factor for at least one node,    determining (S 3 ), for each access network, a user perceived data quality, based on said determined utilization factor and said determined radio quality for the access network, and    selecting (S 4 ) at least one of said access networks, based on the determined user perceived quality.    
   
   
       2 . The method according to  claim 1 , characterized by the further steps of estimating a radio link bitrate μ for each access, based on the determined radio quality q, and 
 determining the user perceived data quality, based on the determined utilization factor and the estimated radio link bitrate.    
   
   
       3 . The method according to  claim 2 , characterized by estimating the radio link bitrate according to: 
       μ=g(q) 
     where g is an access specific function.  
   
   
       4 . The method according to  claim 3 , characterized in that the radio link quality q is represented by at least any one of pilot signal strength, beacon signal strength, Ec/N 0 , SIR, C/I, bit error rate, block error rate, and packet error rate.  
   
   
       5 . The method according to  claim 2  or  3 , characterized by determining (S 3 ) the user perceived quality Q u  according to: 
       Q u   =μ*f (ρ) 
     where μ represents the radio link bitrate, and ρ represents the utilization factor for the access.  
   
   
       6 . The method according to  claim 2  or  3 , characterized by determining (S 3 ) the user perceived quality according to: 
         Q   u =μ*(1−ρ) 
     where μ represents the radio link bitrate, and ρ represents the utilization factor for the access.  
   
   
       7 . The method according to any of claims  2 - 6 , wherein μ is constant.  
   
   
       8 . The method according to any of claims  5 - 7 , wherein ρ is constant.  
   
   
       9 . The method according to  claim 5 , wherein the function f(ρ) is specific for each type of access network.  
   
   
       10 . The method according to any of the above claims, characterized by representing said user perceived quality with a data bit rate for the access network.  
   
   
       11 . The method according to any of  claims 1  to  9 , characterized by representing said user perceived quality with an active session data throughput for the access network.  
   
   
       12 . The method according to  claim 10 , wherein said data bitrate comprises an estimated Session Circuit Switched Equivalent (CSE) bitrate.  
   
   
       13 . The method according to  claim 5  or  6 , wherein ρ is estimated by the expression:  
     
       
         
           
             
               ρ 
               = 
               
                 1 
                 - 
                 
                   
                     P 
                     CCH 
                   
                   
                     P 
                     TOT 
                   
                 
               
             
             , 
           
         
       
     
     where P CHH  is the common power, and P TOT  is the total power.  
   
   
       14 . The method according to  claim 13 , wherein P CHH  is estimated from the received pilot power and a factor F CCH  that compensates for the other common channels, and P TOT  is estimated from the received wideband signal strength.  
   
   
       15 . The method according to  claim 14 , characterized by determining (S 2 ) the utilization by measuring at least a received pilot power SS pilot  and a total power SS out  from a received wideband signal strength, whereby the utilization as represented by ρ is estimated.  
   
   
       16 . The method according to  claim 1 , characterized by selecting (S 4 ) the at least one access before the terminal is connected to an access.  
   
   
       17 . The method according to  claim 1 , wherein said accesses utilize the same type of radio access technology.  
   
   
       18 . The method according to  claim 1 , wherein said accesses utilize different types of radio access technologies.  
   
   
       19 . The method according to  claim 1 , wherein said accesses belong to the same network.  
   
   
       20 . The method according to  claim 1 , wherein said accesses belong to different networks.  
   
   
       21 . The method according to  claim 1 , wherein said accesses belong to the same operator.  
   
   
       22 . The method according to  claim 1 , wherein said accesses belong to different operators.  
   
   
       23 . The method according to any of the above claims, wherein the one or more accesses include at least one of WCDMA, CDMA2000, GSM, WLAN or GPRS.  
   
   
       24 . The method according to any of the previous claims, wherein said node comprises at least one of an access point, and base station.  
   
   
       25 . A system enabling selection of an access network from among one or more access networks capable of providing service to a mobile communication station, characterized by: 
 means ( 12 ) for determining a radio quality from the terminal ( 10 ) to each access network ( 20 ),    means ( 13 ) for determining, for each access network ( 20 ), a utilization factor for at least one access point,    means ( 14 ) for determining, for each access network ( 20 ), a user perceived data quality, based on said determined utilization factor and said determined radio quality for the access network, and    means ( 15 ) for selecting at least one of said access networks, based on the determined user perceived quality.    
   
   
       26 . The system according to  claim 25 , characterized in that said determining means ( 12 ) further comprise means ( 12 ′) configured to estimate a radio link bitrate μ for each access, based on the determined radio quality q, and 
 said determining means ( 14 ) are further configured to determine the user perceived data quality, based on the determined utilization factor and the estimated radio link bitrate.    
   
   
       27 . The system according to  claim 26 , characterized in that said estimating means ( 12 ′) are configured to estimate the radio link bitrate according to: 
       μ=g(q) 
     where g is an access specific function.  
   
   
       28 . The system according to  claim 25 , characterized in that said user perceived data quality determining means ( 14 ) are configured to determine the user perceived quality according to: 
       μ*f(ρ) 
   
   
       29 . The system according to  claim 25 , characterized in that said user perceived data quality determining means ( 14 ) are configured to determine the user perceived quality according to: 
       μ*(1−ρ) 
   
   
       30 . The system according to  claim 28  or  29 , characterized in that said utilization determining means ( 13 ) are configured to estimate ρ according to:  
     
       
         
           
             
               ρ 
               = 
               
                 1 
                 - 
                 
                   
                     P 
                     CCH 
                   
                   
                     P 
                     TOT 
                   
                 
               
             
             , 
           
         
       
     
     where P CHH  is the common power, and P TOT  is the total power.  
   
   
       31 . The system according to  claim 30 , characterized in that P CHH  is estimated from the received pilot power and a factor F CCH  that compensates for the other common channels, and P TOT  is estimated from the received wideband signal strength.  
   
   
       32 . The system according to  claim 31 , characterized in that the utilization is determined by measuring at least a received pilot power SS pilot  and a total power SS out  from a received wideband signal strength, whereby the utilization as represented by ρ is estimated.  
   
   
       33 . The system according to any of claims  26 - 29 , characterized in that said radio quality determining means ( 12 ) are further configured to estimate μ based on at least one of pilot signal strength, beacon signal strength, Eb/N 0 , SIR, and C/I.  
   
   
       34 . The system according to any of claims  25 - 33 , characterized in that said node comprises at least one of an access point, and base station.  
   
   
       35 . A mobile communication station ( 10 ) capable of receiving service from one or more access networks ( 20 ), characterized by: 
 means ( 12 ) for determining a radio quality from the terminal ( 10 ) to each access network ( 20 ),    means ( 13 ) for determining, for each access network ( 20 ), a utilization factor for at least one node,    means ( 14 ) for determining for each access network ( 20 ), a user perceived data quality, based on a utilization factor for the access network ( 20 ), and    means ( 15 ) for selecting at least one of said access networks, based on the determined user perceived quality and the radio quality.