METHOD AND ARRANGEMENTS IN A RADIO COMMUNICATION SYSTEM

Abstract: The present invention relates to a method and an arrangement for performing a paging procedure in a radio communication system comprising a radio communication network and at least a first mobile station. Upon receiving a request for establishment of a call to the first mobile station, the radio communication network initiates (201) the paging procedure. A page signal is transmitted (202) to the first mobile station. Upon detecting (203) a deficiency in the paging procedure which potentially is due to radio signals transmitted between the first mobile station and the radio communication network being subject to excessive propagation loss, an alert signal is generated (204) to the user of the first mobile station. After performing redeeming actions aming at providing more favourable conditions for radio communication, the user triggers (205) the first mobile station to transmit (206) a manual page response signal to the radio communication network.

Description: METHOD AND ARRANGEMENTS IN A RADIO COMMUNICATION SYSTEM TECHNICAL FIELD OF THE INVENTION The invention relates to a method in a radio communication system comprising a radio communication network and a mobile station. More specifically, the invention relates to a method of establishing calls to the mobile station and in particular a paging procedure component in the call establishment method. The invention includes a radio communication system in which the method is implemented and a mobile station for use in said radio communication system. DESCRIPTION OF RELATED ART Radio signals transmitted between a radio communication network and mobile stations operating within an geographic area served by the radio communication network experiences propagation loss. The amount of propagation loss experienced at any given moment of time when transmitting radio signals between a mobile station and the radio communication network depends on many different factors including whether the mobile station antenna is retracted or not, the mobile station is located inside or outside a building and, if located inside a building, whether the mobile station is located in the basement of the building or near a window etc . Typically when a user of the mobile station wants to initiate a call to another party, he or she extracts the antenna and moves the mobile station to a position more favourable for radio communication. Thus the amount of propagation loss is reduced and radio signals exchanged between the mobile station and the radio communication network are sufficiently strong, when received by radio receivers in the radio communication network and mobile station respectively, to enable reliable communication. In a situation where another party initiates a call to the mobile station user, the mobile station user is typically not expecting to receive a call and hence the mobile station may be placed in a bag with its antenna retracted and/or currently located in the basement of a building etc. Thus radio signals exchanged between the mobile station and the radio communication network may be subject to excessive propagation loss which renders reliable communication impossible. In order to provide reliable communication, the propagation loss must be reduced and/or the radio signals must be transmitted at a higher power level . International patent application W097/42787 teaches a communication system including a plurality of mobile radio telephones, a control unit for transmitting a signalling message to an intended mobile radio telephone and at least one paging channel through which the control unit is able to transmit the signalling message at varying link margin levels. The control unit initially transmits the signalling message at a specified margin level for a predetermined number of attempts and then progressively continues to transmit the signalling message at margin levels greater than the specified margin level until the intended mobile radio telephone receives the signalling message. Higher margin levels can e.g. be achieved by transmitting at a higher power level or using other modulation techniques . The intended mobile radio telephone provides a signal to alert its user that a message is received through the paging channel at a margin level greater than the specified margin level. International patent application WO 98/13954 discloses a mobile station communication system including a high penetration network which schedules transmission of paging signals at high transmission power level to reach a mobile station for which an acknowledgement signal is not received when transmitting paging signals at normal transmission power. WO 98/13954 also discloses a mobile station which upon receiving the paging signals transmitted at high transmission power level, provides visual and oral feedback to a user of the mobile station in order to inform the mobile station user that the communication system needs to overcome temporary signal path interference to establish communication. Neither of the communication systems disclosed in the above referenced international patent applications provide the mobile station user with an option of performing redeeming actions aiming at providing more favourable conditions for radio communication prior to acknowledging the high margin/high power page respectively. Likewise, neither of said communication systems provide the mobile station user with a possibility of performing redeeming actions in situations where a page response is received from the mobile station, but the radio signals received from the mobile station are still to weak for reliable communication. SUMMARY OF THE INVENTION The problem dealt with by the present invention is to increase the probability that in a radio communication system, comprising a radio communication network and at least a first mobile station, a request for establishment of a call to the first mobile station will result in a successful call establishment. The problem is solved essentially by a method in which upon detecting a deficiency when paging the first mobile station, the radio communication system alerts a user of the first mobile station that redeeming actions aiming at providing more favourable conditions for radio communication are needed in order to enable reliable radio communication between the first mobile station and the radio communication network. After performing some kind of redeeming action, e.g. extracting the antenna and/or moving close to a window, the user triggers transmission of a manual page response signal from the first mobile station to the radio communication network. Different aspects of the invention includes the method, a communication system with the necessary means for performing the method and a mobile station. More specifically, the problem is solved in the following manner. After receiving the request for call establishment, the radio communication network initiates a paging procedure . A page signal is transmitted to the first mobile station. Upon detecting a deficiency in the paging procedure which at least potentially is due to radio signals transmitted between the first mobile station and the radio communication network being subject to excessive propagation loss, an alert signal is generated to the user of the first mobile station. A manual page response signal is transmitted from the first mobile station to the radio communication network upon the first mobile station receiving a user input action. A general object of the invention is to increase the probability of successful establishment of calls to mobile stations in a radio communication system. Another object is to enable a user of a first mobile station to perform redeeming actions aming at providing more favourable conditions for radio communication in connection with establishment of an incoming call to the first mobile station. Still another object is to enable the mobile station user to trigger transmission of a manual page response signal from the first mobile station to the radio communication network after performing said redeeming actions. One advantage afforded by the invention is an increased probability of successful establishment of calls to mobile stations in a radio communication system. Yet another advantage is that the increased probability of successful call establishment may be achieved without requiring a radio communication network to use different transmitting power and/or different modulation schemes when transmitting radio signals. Still another advantage is that a user of a first mobile station may perform redeeming actions aming at providing more favourable conditions for radio communication in connection with establishment of an incoming call to the first mobile station. Yet another advantage is that the invention enables its user to trigger transmission of a manual page response signal from the first mobile station to the radio communication network after performing said redeeming actions. The invention will now be described in more detail with reference to exemplifying embodiments thereof and also with reference to the accompanying drawings . BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of a radio communication system comprising a radio communication network and a mobile station Fig. 2 is a flow chart illustrating the inventive method in general terms . Fig. 3 is a flow chart illustrating a first embodiment of the inventive method. Fig. 4 is a flow chart illustrating a second embodiment of the inventive method. Fig. 5 is a flow chart illustrating a third embodiment of the inventive method. Fig. 6 is a signalling diagram illustrating a signalling sequence according to the first embodiment of the inventive method. Fig. 7 is a signalling diagram illustrating a signalling sequence according to the second embodiment of the inventive method. Fig. 8 is a signalling diagram illustrating a signalling sequence according to the third embodiment of the inventive method. Fig. 9 is a schematic blockdiagram of a mobile station according to the invention. DETAILED DESCRIPTION OF THE EMBODIMENTS Fig. 1 illustrates a radio communication system SYS1 comprising a radio communication network in the form of a cellular network NET1 and a first mobile station MSI. In the examplifying radio communication system SYS1 illustrated in Fig. 1, communication between the cellular network and the first mobile station MSI is based on the TIA/EIA IS-136 air interface specifications. Note that the invention is applicable to a multitude of different air interface specifications and is in no way limited in its application to only TIA/EIA IS-136 compliant radio communication systems. The cellular network NETl comprises a mobile services switching centre MSC1 and base stations BS1-BS5 connected to the mobile services switching centre MSC1. The base stations BS1-BS5 provide radio coverage in a geographical area served by the mobile services switching centre MSC1. The geographical area is divided into a number of cells C1-C5. In each cell C1-C5 radio coverage is provided by one of the base stations BS1-BS5 respectively. The cell Cl in which the first mobile station MSI is currently located is denoted the serving cell and the corresponding base station BS1 is denoted the serving base station. Cells C1-C3 constitute a first location area LAI and cells C4-C5 constitute a second location area LA2. The mobile services switching centre MSC1 is responsible for switching calls to and from mobile stations located in the geographical area served by the mobile services switching centre MSCl . Note that in Fig. 1 only elements necessary for illustrating the present invention are illustrated and that a typical cellular network comprises several mobile services switching centres, a greater number of base stations as well as other types of nodes such as home location registers. Radio signals Sll transmitted from the serving base station BSl to the first mobile station MSI and vice versa experience propagation loss Lll. The amount of propagation loss experienced at any given moment in time depends on many different factors including whether the mobile station antenna is retracted or not, the first mobile station MSI is located inside or outside a building and, if located inside a building, whether the first mobile station MSI is located in the basement of the building or near a window etc . Typically when a user of the first mobile station MSI wants to initiate a call to another party, he or she extracts the mobile station antenna and moves the first mobile station MSI to a position favourable for radio communication such that the amount of propagation loss is reduced and the radio signals exchanged between the first mobile station MSI and the serving base station BSl have sufficient strength, when received by radio receivers in the serving base station BSl and the first mobile station MSI respectively, to enable reliable communication. In a situation where another party initiates a call to the user of the first mobile station MSI, the user is typically not expecting to receive a call and hence the first mobile station MSI may be placed in a bag with its antenna retracted and/or the user together with the mobile station MSI may currently be located down in the basement of a building etc. Thus radio signals exchanged between the first mobile station MSI and the serving base station BSl may be subject to excessive propagation loss which renders reliable communication impossible. Fig. 2 illustrates the basic method according to the present invention when implemented in the radio communication system SYS1 illustrated in Fig. 1. Upon receiving a request for establishment of a call to the first mobile station MSI, the mobile services switching centre MSCl initiates a paging procedure at step 201. The mobile services switching centre MSCl determines in which area the first mobile station MSI is to be paged based on previous registrations made by the first mobile station MSI in a well known manner. In this example scenario, the mobile services switching MSCl decides to page the first mobile station MSI in the first location area LAI. The mobile services switching centre MSCl orders each of the base stations BS1-BS3 serving the cells C1-C3 in the first location area LAI to transmit a page signal, i.e. a TIA/EIA IS-136 page message containing the mobile station identification number (MIN) of the first mobile station MSI. At step 202, each of said base stations BS1-BS3 transmits the page signal in its respective cell C1-C3. At step 203 the radio communication system SYS1 detects a deficiency in the paging procedure which potentially is due to radio signals transmitted between the first mobile station MSI and the cellular network NETl being subject to excessive propagation loss. This deficiency may either be detected in the radio communication network NETl or in the first mobile station MSI. Upon detecting said deficiency, the first mobile station MSI generates an alert signal to its user at step 204. The alert signal notifies the user that redeeming actions for providing more favourable conditions for radio communication are necessary in order to receive an incoming call. After the user has performed redeeming actions, such as extracting the mobile station antenna and/or moving close to a window, the first mobile station MSI receives at step 205 a specific input action from the user which the first mobile station MSI recognizes as a request for transmission of a manual page response signal to the cellular network NETl. At step 206 the first mobile station transmits a manual page response signal, i.e. a manual page response message containing the mobile station identification number of the first mobile station MSI, to the serving base station BSl. The content of the manual page response signal may be identical to an ordinary TIA/EIA IS-136 page response message automatically transmitted by the first mobile station MSI upon the receipt of a page signal. The content of the manual page response signal may also contain some explicit indication, e.g. a specific message type field, which enables the cellular network NETl to recognize the signal as a manual page response signal. Provided that the redeeming actions performed by the user have sufficiently reduced the propagation loss Lll, the cellular network NETl receives the manual page response signal with sufficient signal strength for reliable communication and initiates voice channel designation. The cellular network NETl together with the first mobile station MSI then proceeds to establish the call in accordance with the procedure specified in TIA/EIA IS-136. Different specific embodiments of the present invention can be derived from the basic method presented in Fig. 2. Fig. 3 illustrates a method according to a first embodiment of the invention. Fig. 6 illustrates the exchange of signals between the radio communication network NETl and the first mobile station MSI when performing the method illustrated in Fig. 3. Method steps 201-202 and 204-206 have already been described in conncetion with Fig. 2 and are not elaborated upon any further. After initiating a paging procedure at step 201 and transmitting a page signal S61 from the base stations BS1-BS3 at step 202, the first mobile station MSI receives the page signal S61 at step 307. Since the first mobile station MSI is operating in idle mode within the serving cell Cl, the first mobile station MSI receives the page signal S61 on a control channel transmitted by the serving base station BSl. The first mobile station MSI recognises that it is being paged from the content of the page signal S61 and transmits an automatic page response signal S62, i.e. an ordinary TIA/EIA IS-136 page response message, to the serving base station BSl at step 308. The serving base station BSl receives the automatic page response signal S62 at step 309. In addition to receiving the automatic page response signal S62, the serving base station BSl also measures the signal strength of the radio signals Sll conveying the automatic page response signal S62 from the first mobile station MSI. The serving base station BSl conveys the content of the automatic page response signal S62 and reports the measured signal strength to the mobile services switching centre MSCl. At step 303 the mobile services switching centre MSCl determines that the measured signal strength is below a first signal strength threshold. The first signal strength threshold defines a lower limit on the signal strength required for ensuring reliable radio communication. The signal strength being below the first signal strength threshold constitutes a deficiency in the paging procedure. In order to try and resolve the situation, the mobile services switching centre MSCl orders the serving base station BSl, i.e. the base station which received the page response message S62, to transmit a manual page signal S63 to the first mobile station MSI at step 310. The content of the manual page signal includes the mobile station identity of the first mobile station MSI and some indication, e.g. a specific message type field, which identifies the signal as a manual page response signal. The first mobile station MSI receives the manual page signal S63 from the serving base station BSl at step 311. The first mobile station MSI recognizes receipt of the manual page signal S63 as a trigger event for alerting the user that redeeming actions are needed and proceeds at step 204 by generating the corresponding alert signal to the user. At step 205, after the user has performed some kind of redeeming actions, the first mobile station MSI receives the specific user input action which triggers the first mobile station MSI to transmit the manual page response signal S64 at step 206. When comparing the signal strength of signals received from the first mobile station MSI to the first signal strength threshold at step 303, either the measured signal strength value or the first signal strength threshold may be adjusted in accordance with the power capabilities of the first mobile station MSI such that all mobile stations have the same geographical cell borders independent of their power capabilities. This implies that a lower signal strength is accepted for a mobile station having low power capabilities as compared to a mobile station having high power capabilities. There are alternative ways of performing step 303, i.e. detecting the signal strength to be unsufficient for reliable communication. One such alternative way is to arrange for the serving base station BSl to measure and report a bit error rate of digital information received from the first mobile station MSI and then, in the mobile services switching centre MSCl, determine the bit error rate to be above a first bit error rate threshold which defines an upper limit on the bit error rate allowed for reliable radio communication. Fig. 4 illustrates a method according to a second embodiment of the invention. Fig. 7 illustrates the exchange of signals between the radio communication network NETl and the first mobile station MSI when performing the method illustrated in Fig. 4. The method comprises the previously described steps 201- 202 and 204-206 which are not elaborated upon any further. At step 201 a paging procedure is intiated and at step 202 a page signal S61 is transmitted from the base stations BS1-BS3. Upon timeout of a timer set when the page signal S61 was transmitted, the mobile services switching centre MSCl detects that no automatic page response signal has been received from the first mobile station MSI. Detecting that no automatic page response signal has been received upon timeout, i.e. that no page response signal has been received within a predetermined time period after transmission of the page signal S61, constitutes a deficiency in the paging procedure potentially due to excessive propagation loss. In order to try and resolve the situation, the mobile services switching centre MSCl orders the base stations BS1-BS3 to transmit a manual page signal S63 to the first mobile station MSI. At step 407 the base stations BS1- BS3 transmits the manual page signal to the first mobile station MSI. The first mobile station MSI receives the manual page signal S63 from the serving base station BSl at step 408. The first mobile station MSI recognizes receipt of the manual page signal S63 as a trigger event for alerting the user that redeeming actions are needed and proceeds at step 204 by generating an alert signal to the user. At step 205, after the user has performed some kind of redeeming actions, the first mobile station MSI receives a specific user input action which triggers the first mobile station MSI to transmit a manual page response signal S64 at step 206. Optionally the radio communication network NETl may decide to try and retransmit the page signal S61 one or several times prior to transmitting the manual page signal S63. It is also of course possible to try and page the first mobile station MSI in a wider area, e.g. within the complete service area of the mobile services switching centre MSCl or within areas served by other mobile services switching centres, prior to transmitting the manual page signal S63. Alternatively at the same time as a page signals S61 is transmitted in the wider area, the manual page signal S63 could be transmitted in the area in which no response to the page signal S61 was encountered. Fig. 5 illustrates a method according to a third embodiment of the invention. Fig. 8 illustrates the exchange of signals between the radio communication network NETl and the first mobile station MSI when performing the method illustrated in Fig. 5. Method steps 201-202 and 204-206 have already been described in conncetion with Fig. 2 and are not elaborated upon any further. After the radio communication network NETl have initiated a paging procedure at step 201 and transmitted a page signal S61 from the base stations BS1-BS3 at step 202, the first mobile station MSI receives the page signal S61 at step 507. The first mobile station MSI recognises that it is being paged from the content of the page signal S61 and transmits automatically an automatic page response signal S62 to the radio communication network NETl at step 508. Since the first mobile station MSI is operating in idle mode within the serving cell Cl and hence have received the page signal S61 on a control channel transmitted by the serving base station BSl, the first mobile station transmits the automatic page response signal S62 to the serving base station BSl. In addition, the first mobile station MSI sets a timer upon transmission of the automatic page response signal S62. At step 503 the first mobile station detects that no further valid signal relating to establishment of the call has been received from the radio communication network NETl upon timeout of the timer. Detecting that no additional valid signal has been received upon timeout, i.e. that no further valid signal has been received within a predetermined time period after transmission of the automatic page response signal S62, constitutes a deficiency in the paging procedure which potentially is due to the automatic page response signal S62 being subject to excessive propagation loss. Hence, the first mobile station MSI recognizes said lack of signals upon timeout as a trigger event for alerting the user that redeeming actions are needed and proceeds at step 204 by generating an alert signal to the user. At step 205, after the user has performed some kind of redeeming actions, the first mobile station MSI receives a specific user input action which triggers the first mobile station MSI to transmit a manual page response signal S64 at step 206. The radio communication system SYS1 may implement any combination of the described three embodiments of the inventive method e.g just one or all three embodiments. In all three embodiments, the mobile services switching centre MSCl acts as a means for initiating the paging procedure upon receipt of the request for establishment of a call to the first mobile station MSI. In the embodiments illustrated in Fig. 3 and Fig. 4, the mobile services switching centre MSCl also acts as a means for detecting the deficiency in a paging procedure which potentially is due to excessive propagation loss. The base stations BS1-BS5 collectively act as a means for transmitting radio signals to the first mobile station MSI and also as a means for receiving radio signals from the first mobile station MSI. In the first embodiment, the base stations BS1-BS5 also act as a means for signal strength measurement or alternatively as a means for bit error rate measurement. The time supervision in the radio communication network NETl should account for that the user of the first mobile station MSI is offered reasonable time to react to the alert signal and to perform redeeming actions prior to requesting transmission of the manual page response signal. Alternatively, the mobile services switching centre MSCl may remember the calling party identity for a predetermined time, e.g a few minutes, after it has abandoned the paging procedure and notified the calling party that the first mobile station MSI is unreachable. If a manual page response signal is received within said predetermined time, the mobile services switching centre MSCl may initiate a call back to the calling party. As a further option, the mobile services switching centre may remember the calling party identity only for those call attempts in which a manual page signal is sent. Fig. 9 contains a schematic block diagram of the first mobile station MSI in accordance with a first embodiment of the present invention. The first mobile station MSI according to Fig. 9 supports all three of the embodiments of the inventive method illustrated in Fig. 3 to Fig. 5. The mobile station MSI comprises an antenna 901, a receiver circuit 902, a transmitter circuit 903, a keyboard 904, a speaker 905, a display 906 and a control processor 907. The receiving circuit 902 acts as a means for receiving and decoding signals, such as e.g. the page signal S61 and manual page signal S63 in Fig. 6, from the cellular network NETl. The transmitter circuit 903 acts as a transmitting means for encoding and transmitting signals, e.g. the automatic page response signal S62 and the manual page response signal S64 in Fig 6, to the cellular network NETl. The speaker 905 and the display 906 together with the corresponding driving circuits (not shown in Fig. 9) act as an alerting means for generating alert signals to a user of the first mobile station MSI. The keyboard 904 acts as a user input means for receiving user input actions. The control processor 907 acts as a control means controlling the overall function of the first mobil station MSI. The control processor 907 includes a timer 908. Under favourable conditions for radio communication, the first mobile station MSI operates as other TIA/EIA IS-136 compliant mobile stations. In response to receiving an indication from the receiving means 902 that a page signal has been received, the control means 907 automatically orders the transmitting means to transmit an automatic page response signal to the cellular network NETl and sets the timer 908. Upon receiving an indication from the receiving means 902 that a valid channel designation signal has been received from the cellular network NETl, the control means 907 resets the timer 908 and orders the receiving means 902 and the transmitting means 903 to tune to an analog voice channel or a digital traffic channel designated in said signal and call setup proceeds according to TIA/EIA IS-136 using the designated channel. Under less favourable conditions for radio communication, the features of the first mobile station MSI related to the present invention is activated. The control means is adapted to recognise two predetermined trigger events indicating that radio signals exchanged with the cellular network NETl are potentially subject to excessive propagation loss, namely: an indication from the receiving means 902 that a manual page signal has been received from the cellular network NETl; or a timeout of the timer 908 indicating that no channel designation signal, i.e. no further valid signal relating to the call establishment, has been received from the cellular network NETl after the transmission of the automatic page response signal. Upon detecting either of the two triggering events, the control means 907 respond by ordering the alerting means 905-906 to generate a trigger related alert signal S91 which informs the mobile station user that redeeming actions are needed to provide more favourable conditions for radio communication. Upon receiving a specific user input action A91 via the keyboard, e.g activation of a predefined key, indicating that the mobile station user requests transmission of a manual page signal, the control means 907 orders the transmitting means 903 to transmit a manual page response signal to the cellular network NETl. The alerting means 905-906 is preferable adapted to generate the trigger related alert signal S91 such that it is distinct from other generated alert signals such as e.g. the normal alert signal indicating an incoming call generated upon receipt of a TIA/EIA IS-136 alert with info message from the cellular network NETl. The generated alert signal S91 may comprise an acoustic component which is generated via the speaker 905 and a text message component which is displayed in the display 906. Preferrably the displayed text advices the mobile station user of suitable actions aiming at providing better conditions for radio communication, i.e. actions which lessen the propagation loss of radio signals exchanged between the radio communication network NETl and the first mobile station MSI. The text message can either be preprogrammed in the first mobile station MSI or included as a text field in the manual page signal. Apart from the examplifying embodiments of the invention disclosed above, there are several ways of providing rearrangements, modifications and substitutions resulting in additional embodiments of the invention. As a person skilled in the art appreciates, application of the invention is in no way limited to only radio communication systems conforming to the TIA/EIA IS-136 specifications. The invention is thus also applicable in systems adhering to e.g. the GSM-, PDC-, IS-95-, AMPS-, TACS-, NMT- , or DECT- specifications . The radio communication system in which the invention is implemented may be a public cellular system, as well as e.g. a PABX-system serving an office or a factory or a cordless system connected to a public telephone network. The present invention does not require a manual page message to be transmitted using e.g a higher power level or other modulation technique than when transmitting a normal page. However the manual page signal may be transmitted in such a high penetration mode using e.g. either of the techniques disclosed in W097/42787 or W098/13954.

Claims: CLAIMS 1. A method for performing a paging procedure in connection with call establishment in a radio communication system (SYSl) comprising a radio communication network (NETl) and at least a first mobile station (MSI), the method comprising the steps of: a) initiating (201) the paging procedure upon receiving a request for call establishment to the first mobile station (MSI) ; b) transmitting (202) a page signal (S61) to the first mobile station (MSI) from the radio communication network (NETl) ; c) detecting (203) a deficiency in the paging procedure which at least potentially is due to radio signals (Sll) transmitted between the first mobile station (MSI) and the radio communication network (NETl) being subject to an excessive propagation loss; d) generating (204) an alert signal (S91) to a user of the first mobile station (MSI) upon detecting said deficiency; c h a r a c t e r i z e d in that the method further comprises the steps of: e) receiving (205) a mobile station user input action (A91) ; f) transmitting (206) a manual page response signal (S64) to the radio communication network (NETl) from the first mobile station (MSI) in response to said received user input action of step e) . 2. A method according to claim l c h a r a c t e r i z e d in that the method further comprises the step of: g) receiving (507) said transmitted page signal (S61) in the first mobile station (MSI) , wherein said deficiency (503) is detected by the first mobile station (MSI) . 3. A method according to claim 2 c h a r a c t e r i z e d in that the method further comprises the step of: h) transmitting (508) an automatic page response signal (S62) from the first mobile station (MSI) to the radio communication network (NETl) in response to the first mobile station (MSI) receiving said page signal (S61) , wherein said deficiency is detected by determining that no further valid signal relating to the call establishment is received by the first mobile station (MSI) from the radio communication network (NETl) within a predetermined time period after transmission of said automatic page response signal (S62). 4 . A method according to claim l c h a r a c t e r i z e d in that said deficiency is detected by the radio communication network (NETl) and that the method further comprises the steps of: i) transmitting (310, 407) a manual page signal (S63) from the radio communication network (NETl) to the first mobile station (MSI) upon detecting said deficiency; j) receiving (311, 408) said transmitted manual page signal (S63) in the first mobile station (MSI), wherein said alert signal (S91) is generated by the first mobile station (MSI) subsequent to said receiving of the manual page signal (S63 ) . 5. A method according to claim 4 c h a r a c t e r i z e d in that the method further comprises the steps of: k) receiving (307) said transmitted page signal (S61) in the first mobile station (MSI) , 1) transmitting (308) an automatic page response signal (S62) from the first mobile station (MSI) to the radio communication network (NETl) in response to said received page signal of step k) ; m) receiving (309) said automatic page response signal (S62) in the radio communication network (NETl) , wherein said deficiency is detected by determining that the radio signals (Sll) transmitted by the first mobile station (MSI) are received by the radio communication network (NETl) with unsufficient signal strength for reliable communication. 6. A method according to claim 5 c h a r a c t e r i z e d in that the signal strength is determined to be unsufficient by measuring the signal strength of the received radio signals and determining the measured signal strength to be below a first signal strength threshold. 7. A method according to claim 5 c h a r a c t e r i z e d in that the signal strength is determined to be unsufficient by measuring a bit error rate of digital information conveyed by the received radio signals and determining the measured bit error rate to be above a first bit error rate threshold. 8. A method according to any one of claims 5-7 c h a r c t e r i z e d in that when the automatic page response signal (S62) is received by the radio communication network in a first cell (Cl) , the manual page signal (S63) is only transmitted in the first cell (Cl) . 9. A method according to claim 4 c h a r c t e r i z e d in that said deficiency is detected by determining that no valid automatic page response signal (S62) from the first mobile station (MSI) is received by the radio communication network (NETl) within a predetermined time period after transmission of said page signal (S61) . 10. A method according to any one of claims 1-9 c h a r a c t e r i z e d in that said alert signal (S91) generated in step d) is distinct from other alert signals generated by the first mobile station (MSI) . 11. A radio communication system (SYS1) comprising a radio communication network (NETl) and at least a first mobile station (MSI), the radio communication system (SYS1) comprising: means (MSCl) in the radio communication network (NETl) for initiating a paging procedure upon receiving a request for establishment of a call to the first mobile station (MSI) ; means (BS1-BS5) in the radio communication network (NETl) for transmitting a page signal (S61) to the first mobile station (MSI) ; means (MSCl, 907) for detecting a deficiency in the paging procedure which at least potentially is due to radio signals (Sll) transmitted between the first mobile station (MSI) and the radio communication network (NETl) being subject to an excessive propagation loss (Lll) ; means (905, 906) in the first mobile station (MSI) for generating an alert signal (S91) to a user of the first mobile station (MSI) upon detecting said deficiency; c h a r a c t e r i z e d in that the radio communication system (SYS1) further comprises: means (904) in the first mobile station (MSI) for receiving a mobile station user input action (A91) requesting transmission of a manual page response signal (S64) ; means (903) in the first mobile station (MSI) for transmitting a manual page response signal (S64) to the radio communication network (NETl) ; . 12. A radio communication system (SYS1) according to claim 11 c h a r a c t e r i z e d in that the radio communication system (SYS1) further comprises: means (902) in the first mobile station (MSI) for receiving said transmitted page signal (S61) , wherein the first mobile station (MSI) contains said deficiency detecting means (907) . 13. A radio communication system (SYS1) according to claim 12 c h a r a c t e r i z e d in that the radio communication system (SYS1) further comprises: means (903) in the first mobile station (MSI) for transmitting an automatic page response signal (S64) to the radio communication network (NETl) in response to the first mobile station (MSI) receiving said page signal (S61) , wherein said detected deficiency is that upon time out of a timer (908) set in the first mobile station (MSI) when transmitting the automatic page response signal (S62), no further valid signal relating to the call establishment has been received by the first mobile station (MSI) from the radio communication network (NETl) . 14. A radio communication system (SYS1) according to claim 11 c h a r a c t e r i z e d in that the radio communication network (NETl) contains said deficiency detecting means (MSCl) and that the radio communication system further comprises: means (BS1-BS5) in the radio communication network (NETl) for transmitting a manual page signal (S63) to the first mobile station (MSI) ; means (902) in the first mobile station (MSI) for receiving said transmitted manual page signal (S61) , wherein said alert signal (S91) is generated by the alert generating means (905, 906) subsequent to said receiving of the manual page signal (S63). 15. A radio communication system (SYS1) according to claim 14 c h a r a c t e r i z e d in that the radio communication system (SYS1) further comprises: means (902) in the first mobile station (MSI) for receiving said transmitted page signal (S61) ; means (903) in the first mobile station (MSI) for transmitting an automatic page response signal (S62) to the radio communication network (NETl) in response to receiving said page signal (S61) ; means (BS1-BS5) in the radio communication network (NETl) for receiving said automatic page response signal (S62), wherein said detected deficiency is that radio signals (Sll) transmitted by the first mobile station (MSI) are received by the radio communication network (NETl) with unsufficient signal strength for reliable communication. 16. A radio communication system (SYS1) according to claim 15 c h a r a c t e r i z e d in that the radio communication network (NETl) comprises: means (BS1-BS5) for measuring the signal strength of said radio signals (Sll) received from the first mobile station (MSI) , wherein said signal strength is determined to be unsufficient by determining the measured signal strength to be below a first signal strength threshold. 17. A radio communication system (SYS1) according to claim 15 c h a r a c t e r i z e d in that the radio communication network (NETl) comprises: means (BS1-BS5) for measuring a bit error rate of digital information conveyed by said radio signals (Sll) received from the first mobile station (MSI) , wherein said signal strength is determined to be unsufficient by determining the measured bit error rate to be below a first bit error rate threshold. 18. A radio communication system (SYS1) according to any one of claims 15-17 c h a r c t e r i z e d in that when the automatic page response signal (S62) is received by the radio communication network (NETl) in a first cell (Cl) , the manual page signal (S63) is only transmitted in the first cell (Cl) . 19. A radio communication system (SYS1) according to claim 14 c h a r c t e r i z e d in that said detected deficiency is that no valid automatic page response signal from the first mobile station (MSI) has been received by the radio communication network (NETl) upon time out of a timer set when transmitting the page signal (S62) . 20. A mobile station (MSI) enabling a mobile station user to receive calls via a radio communication network (NETl) when the mobile station (MSI) is active within an area served by the radio communication network (NETl) , the mobile station (MSI) comprising: - receiving means (902) for receiving and decoding radio signals from the radio communication network (NETl) ; - transmitting means (903) for encoding and transmitting radio signals to the radio communication network (NETl) ; - alerting means (905, 906) for generating alert signals to the mobile station user; - user input means (904) for receiving user input actions; - control means (907) coupled to the other means (902-906) and controlling the overall function of the mobile station (MSI), wherein the control means (907) is adapted to recognise at least one predetermined trigger event (408, 503) indicating a deficiency in a paging procedure, which at least potentially is due to the radio signals (Sll) exchanged with the radio communication network (NETl) being subject to an excessive propagation loss, and to respond to this at least one trigger event (408, 503) by ordering the alerting means to generate a trigger related alert signal (S91) , the alerting means (905, 906) is adapted to generate the trigger related alert signal in response to receiving an order to do so from the control means (907), c h a r a c t e r i z e d in that the control means (907) is adapted to recognise a specific user input action (A91) , performed by the mobile station user and received via the user input means (904) , as a request for transmission of a manual page response signal (S64) to the radio communication network (NETl) and to respond to said request by ordering the transmitting means (903) to encode and transmit a manual page response signal (S64) to the radio communication network (NETl), and that the transmitting means (903) is adapted to encode and transmit a manual page response signal (S64) to the radio communication network (NETl) in response to receiving an order to do so from the control means (907) . 21. A mobile station (MSI) according to claim 20 c h a r a c t e r i z e d in that the receiving means (902) is adapted to generate a manual page receipt indication to the control means (907) upon receipt of a valid manual page signal (S63) from the radio communication network (NETl) , and that the control means (907) is adapted to recognise a manual page receipt indication from the receiving means (903) as one of said at least one trigger events (408) . 22. A mobile station (MSI) according to claim 20 or claim 21 c h a r a c t e r i z e d in that the mobile station (MSI) comprises a timer (908) which is set by the control means (907) upon ordering transmission of an automatic page response signal (S62) in response to receipt of a valid page signal (S61) from the radio communication network (NETl) , and that the control means (907) is adapted to recognise a situation where no further valid signals relating to the call establishment have been received by the first mobile station (MSI) from the radio communication network (NETl) upon time out of the timer (908) as one of said at least one trigger events (503). 23. A mobile station (MSI) according to any one of the claims 20-22 c h a r a c t e r i z e d in that the alerting means (905, 906) is adapted to generate the trigger related alert signal (S91) such that it is distinct from other alert signals generated by the alerting means (905, 906) .

Inventors: BRINGBY DANIEL, HOFF ANDERS, BRINGBY, DANIEL, HOFF, ANDERS
Applicants: ERICSSON TELEFON AB L M, TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Application year: 1999
Main classification: H04Q7
IPC codes: H04W68, H04W88