in fig1 , a general view of a radio network system 100 covering an area is depicted . in the exemplary embodiment depicted in fig1 , the radio network system is a gsm system . the gsm system 100 comprises a base station ( bs ) 101 . the base station 101 serves a number of mobile terminals ; usually termed mobile stations ( ms ) 103 , located within the area covered by the base station 101 . the base station 101 is also connected to a base station controller ( bsc ) 105 . the base station 101 and bsc 105 are both part of the base station subsystem ( bss ) the base station subsystem ( bss ) is the section of a gsm network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem . the bss carries out transcoding of speech channels , transporting packet switched data , allocation of radio channels to mobile phones , paging , quality management of transmission and reception over the air interface and many other tasks related to the radio network including transmitting the base station identity code bsic information as a broadcast message on the sch channel . due to the relatively relaxed requirement on the bsic decoding frequency , i . e . once every 30 seconds , a mobile station may not set up the call during call set - up using the base station providing the strongest signal if the mobile station has moved since the last decoding of the base station identity code bsic information . the problem becomes even worse if the mobile station is traveling at a high speed , such as when a person is riding on a train or in a bus , because then the best base station may be shifting at a very high rate indeed . the relaxed bsic decoding requirements can result in that the mobile station is performing signal strength measurements on the wrong cell . if the bcch frequency planning is such that it is possible for a mobile station to do signal strength measurements on 2 different cells that are using the same bcch frequency , within 30 seconds then it is possible that the mobile station performs an access to a less preferred cell . the relaxed requirement on the signal strength measurements is another source for setting up a call in the wrong cell . in case the radio environment is changing due to high speed or similar , it is common problem that the mobile does not set up the call on the strongest cell . if a mobile station tries to set up a call to base station not providing the strongest signal , then there is a risk that the call could be dropped . this is particularly the case when the mobile station is traveling away from a base station that the mobile station tries to set up the connection to . in order to reduce the likelihood of dropping a call during call set - up the mobile station is adapted to employ two types of idle modes . hence , there is a conventional first idle mode that is used most of the time when the mobile station is not connected to a base station , i . e . in an active mode , and a second mode that is entered when there is an increased likelihood that the mobile station is to set up a call to within the near future . this is described more in detail below in conjunction with fig2 . in fig2 different modes used by a mobile station are illustrated . to address the above described problem a “ semi active ” mode is introduced in addition to the idle mode and the active mode . the normal state when not connected to a cellular radio system for the mobile station is the idle mode . if while the mobile station is in the idle an incoming call is received by the mobile station , the mobile station will transit directly from an idle mode to an active mode as indicated by the arrow 201 . in a preferred embodiment this is the only event triggering a transition directly from the idle mode to the active mode . furthermore , when the mobile station is in the active mode and a connection to the cellular radio network is terminated , the mobile station can transit directly from the active mode to the idle mode as indicated by arrow 203 . however , in a preferred embodiment the transition from the active mode to the idle mode is via a third mode denoted “ semi - active ” in fig2 . the transition via the semi - active mode is described below . if , while in the idle mode the user of the mobile station initiates some pre - determined activity , such as pushing a button on the mobile station or starts to enter a telephone number on the mobile station or opens the telephone book with stored telephone numbers , the mobile station will transit to a “ semi - active ” mode as indicated by arrow 205 . the semi active mode is a mode where the mobile station performs radio measurements as in the idle mode . however , the radio measurements are performed more often than is the case in the idle mode . for example in a gsm system the bsic decoding is typically performed at least every 30 seconds when in the idle mode in accordance with the requirements of the gsm standard . in the semi active mode , radio measurements can be performed every 5 seconds or even more often if that is determined to be advantageous such as every 3 seconds or even more often than that . furthermore , the signal strength measurements rate can also be increased when the mobile station is in the semi active mode . this can be done by updating the running average of received signal level ( rla_c ) more than once every 5 seconds , e . g ., once every second . in addition , more than 5 received signal level measurement samples can be required per rla_c value , e . g . 20 . also , in accordance with 3gpp specification 45 . 008 the mobile station is required to perform the following measurements to ensure that the path loss criterion to the serving cell is acceptable . at least every 5 s the ms shall calculate the value of c 1 and c 2 for the serving cell and re - calculate c 1 and c 2 values for non serving cells ( if necessary ). the mobile station shall then check whether : i ) the path loss criterion ( c 1 ) for current serving cell falls below zero for a period of 5 seconds . this indicates that the path loss to the cell has become too high . ii ) the calculated value of c 2 for a non - serving suitable cell exceeds the value of c 2 for the serving cell for a period of 5 seconds , except ; a ) in the case of the new cell being in a different location area or , for a gprs attached ms , in a different routing area or always for a gprs attached ms in gmm ready state ( a / gb mode ) or rrc - cell_shared state ( iu mode ) in which case the c 2 value for the new cell shall exceed the c 2 value of the serving cell by at least cell_reselect_hysteresis db as defined by the bcch data from the current serving cell , for a period of 5 seconds ; or b ) in case of a cell reselection occurring within the previous 15 seconds in which case the c 2 value for the new cell shall exceed the c 2 value of the serving cell by at least 5 db for a period of 5 seconds . thus , c 2 shall be higher than c 1 for 5 seconds for a cell - reselection to occur . however , while in semi active mode this time is reduced to a time period less than 5 seconds , e . g . 2 seconds or even less . furthermore if the mobile station has been in the semi active mode without entering the active mode and there have been no new events triggering the entrance to the semi active mode for some predetermined time interval , for example 3 minutes , then the mobile station is adapted to return to the idle mode as indicated by arrow 207 . however , if while in the semi active mode a command to set - up a connection to the base station , such as by the user pressing a cell button , the mobile station is adapted to transit from the semi active mode into the active mode as shown by the arrow 209 . also , after disconnecting the connection to the base station , the mobile station is preferably adapted to return to the semi active mode as indicated by the arrow 211 . as an alternative the mobile station could return directly to the idle mode as described above . in fig3 , a flow chart illustrating a typical scenario when a user connects to a base station is shown . thus initially the mobile station is in an idle mode as indicated by step 301 . the mobile station then continuously executes a procedure where it checks if a trigger event has occurred step 303 . a trigger event can be any type of event that has been set in the mobile station . typically , a trigger event is an event that increases the likelihood that the mobile station will enter an active mode in the near future . examples of such events include opening the address list or entering a telephone number on a key pad on the mobile station . if such a trigger event has not occurred , the mobile station remains in the idle mode . if however a trigger event has occurred , the mobile station enters a semi active mode as described above in conjunction with fig2 and indicated at step 305 . if while in the semi active mode the mobile station is given a command to set up a call as shown in step 307 , the procedure described in conjunction with fig3 will continue to a step 309 . in step 309 , the mobile station enters the active mode . if however while in the semi active mode no new trigger events are detected for some pre - set inactivity time or the procedure enters the active mode during the inactivity time , the procedure returns to step 301 . after the connection with the cellular radio system shown by step 309 ends , the procedure returns to the step 305 , i . e . the semi active mode . by using the mobile station and the method as described herein , the amount of failures or dropped calls at call setup will be significantly reduced , because it is ensured or at least much more likely that a mobile station is adapted to connect to the cell providing the strongest signal at call setup . furthermore , the mobile station and the method as described herein will also reduce the amount of cell re - selection in during packed data transfers . finally , minimizing the number of calls set - up to non - strongest cells will have a positive effect on the overall interference level .