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(11) | EP 1 434 457 B9 |
| (12) | CORRECTED EUROPEAN PATENT SPECIFICATION |
| Note: Bibliography reflects the latest situation |
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Method of reselecting a cell by a mobile terminal in IDLE mode in a cellular telecommunication network Verfahren zur Zellenwiederwahl durch ein mobiles Endgerät im Leerlaufbetrieb in einem zellularen Telekommunikationsnetzwerk Procédé de resélection de cellule par un terminal mobile en mode veille dans un réseau de télécommunication cellulaire |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
BACKGROUND OF THE INVENTION:
1. Field of the Invention:
[0001] The invention is in the field of telecommunications, and more specifically, it relates to a method of reselecting a cell by a mobile terminal in idle mode in a cellular telecommunication network in which the network sends to the mobile terminal a list containing information with regard to the cells to be identified, and in which the mobile terminal periodically performs a series of procedures of identifying the cells and a series of intersystem measurements on the identified cells.
[0002] The invention also relates to a GSM (Global System for Mobile communication)-UMTS (Universal Mobile Telephone service) dual mode mobile terminal comprising means for periodically performing a series of procedures of identifying UMTS cells and a series of intersystem measurements on the identified cells.
2. Description of the Related Art:
[0003] In a cellular network, a mobile terminal is connected to a particular cell of the network, which will be referred to as current cell in the description below.
[0004] In order to prepare for reselection of a cell, the network sends to the mobile terminal the list of the neighboring cells in which the access technology is the same as the one implemented in the current cell, as well as the cells in which a different access technology is implemented.
[0005] When the measurements are performed on a radio access network whose technology is different from that in the serving cell, they are called "intersystem measurements." The technical specifications of 3GPP (Third Generation Partnership Project) define a minimum duration, as well as a maximum duration for performing intersystem measurements on the identified cells, and a duration limit for performing reselection of a cell. However, these specifications do not impose the use of a particular algorithm of measurements to allow a GSM/UMTS dual mode terminal which is in an idle mode to reselect a UMTS cell from a current GSM cell. The idle mode is a mode in which the terminal is not in communication.
[0006] Recall that in idle mode, the terminal enters in a state "of sleep" in order to save the available energy in its battery to the maximum. However, the terminal must "wake up" from time to time to search for new cells and reselect one of them if the reception quality is better than the one measured in the current cell.
[0007] EP-A- 0 888 026 generally describes a method for transmitting information about neighbouring cells form the base station of a cellular radio system to a mobile station. The base station creates a message comprising information about the neighbouring cells and transmits it to the mobile station, this information including the transmission frequencies, but also other information characterizing the neighbouring cells in said message such as the quality of service offered by each of the neighbouring cells mentioned.
[0008] WO 00/27158 A concerns the idle mode handling in a hybrid GSM/CDMA network including intersystem managements.
[0009] The "Digital cellular telecommunications system (Phase 2);Radio subsystem link control (GSM 05.08)" EUROPEAN TELECOMMUNICATION STANDARD, XX, XX, 31 January 1997 (1997-01-31), pages 1-37, XP002111809 discloses general information regarding the monitoring of received level and BCCH data (c.f. section 6.6.1).
SUMMARY OF THE INVENTION:
[0010] The object of the invention is to propose a method of reselecting method which allows for performing measurements within delays predefined by the technical specifications while extending the life of the battery of the mobile terminal and preserving the reliability of the measurements.
[0011] To this end, the invention proposes a method of reselecting a cell by a mobile terminal in idle mode in a cellular telecommunication network according to claim 1.
[0012] According to the invention, the mobile terminal may perform a confirmation measurement at the end of a maximum duration of five seconds at most following the identification of a new cell.
[0013] In a preferred embodiment, the intersystem measurements and the procedures of identifying cells are performed with the same frequency.
[0014] In a second embodiment, the intersystem measurements are performed with a frequency that is higher than the one for the procedures of identification.
[0015] The method according to the invention may further comprise the following steps of:
comparing the measurements performed for each cell against a predefined selection criterion, and
reselecting the UMTS cell according to the result of the comparing step.
[0016] In a variant embodiment, the method comprises a step of performing the measurements on sliding time windows so as to obtain a mean value of the measurements.
[0017] The invention also relates to a GSM-UMTS dual mode mobile terminal in idle mode in a GSM cell comprising means for periodically performing a series of procedures of identifying UMTS cells and a series of intersystem measurements on the identified cells.
[0018] According to the invention, the mobile terminal further comprises:
means for allocating, every 20 seconds, a time window for identifying new UMTS cells among a plurality of UMTS cells indicated to the mobile terminal by the network, the time windows being alternately assigned to the various carrier frequencies used in the cells of the network,
means for simultaneously performing, every five seconds, measurements on the UMTS cells already identified belonging to the same carrier frequency.
[0019] Preferably, the mobile terminal may comprise means for performing a confirmation measurement on each new cell identified and satisfying a predefined reselection criterion, the confirmation measurement being performed at most five seconds after the identification of that new cell.
[0020] According to the present invention, the measurements can be performed within delays predefined by the technical specifications while the life of the battery of the mobile terminal is extended and the reliability of the measurements is preserved.
[0021] Other characteristics and advantages of the invention will be apparent from the following description, made by way of non-limiting example with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS:
[0022]
FIG. 1 is a time diagram illustrating a first embodiment of the invention;
FIG. 2 is a time diagram illustrating a second embodiment of the invention; and
FIG. 3 is a block diagram illustrating an example of a mobile terminal according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0023] The following description relates to a procedure of reselecting a UMTS cell by a GSM/UMTS dual mode mobile terminal in idle mode in a GSM cell. Recall that in order to prepare for the reselecting of the UMTS cell, the network sends to the mobile terminal a list of GSM cells and a list of neighboring UMTS cells containing at least information with regard to the UMTS cells to be identified such as for example a CDMA code or the carrier frequency used in the neighboring cells of the list. The terminal has to first identify a UMTS cell among all cells of the list that are in its radio environment. To this end, the terminal receives, for example, a unique CDMA code of the UMTS cell to be identified and uses this code to estimate the time base of the cell by a procedure of calculation defined by the technical specifications of 3GPP. The cell will be identified when its time base and its signature are determined by this procedure of calculation.
[0024] For each cell thus identified, the mobile terminal performs periodical measurements and applies a selection criterion defined by the technical specifications according to the result of these measurements. When this criterion is satisfied, the terminal can take the decision to switch to the one of the UMTS cells identified and measured.
[0025] FIG. 1 schematically shows a first embodiment of the method in which the terminal periodically performs a series of procedures of identifying cells and a series of intersystem measurements on the identified cells.
[0026] This embodiment comprises a first step that consists in allocating every period Tp = 20 seconds a time window for identifying new UMTS cells, the GMS network supplying CDMA codes associated with them. These successive time windows are allocated alternately to various carrier frequencies in the list given by the network to the mobile terminal. In the case of FIG. 1, three carrier frequencies f0, f1 and f2 are used by the base stations of the network. A first time window 2 is allocated to the identification of the cells in which the network uses the carrier frequency f0, a second time window 4, opening twenty seconds later, is dedicated to the identification of the cells in which the network uses the carrier frequency f1, and a third time window 6, opening twenty seconds later, is allocated to the identification of the cells in the carrier frequency f2.
[0027] Each period Tp of twenty seconds is subdivided into four subperiods 8 of five second duration, each comprising a first interval TCi during which the mobile terminal carries out a procedure of identifying a new cell in one of the carrier frequencies f0, f1 or f2, and a second interval Tcmu during which the mobile terminal performs measurements in the cells that have already been identified and in which the network uses the carrier frequency f0, f1 and f2.
[0028] In a preferred embodiment of the invention, those measurements may be averaged in accordance with the principle of sliding windows filtering.
[0029] The new cells that are identified in due course are integrated into the next interval Tcmu for measurement.
[0030] When a new cell is identified as indicated by arrow 10 and if this cell satisfies the reselection criterion defined in the specifications [3GPP 05.08 Sections 6.6.5], it is measured again, as indicated by arrow 12, five seconds after it becomes better. Prior to this, the terminal performs, in the interval that follows the point indicated by the arrow 10 corresponding to the identification of the new cell, measurements on all the other UMTS cells already identified in order to make sure that none of them has become better in the meantime.
[0031] Thus, after the new UMTS cell has been identified and it has been confirmed to have the best quality in comparison with the current GSM cell and the UMTS cells identified in advance, a new window for measurements is opened. In this window, the UMTS cells identified in due course, as well as the cells identified in advance are measured. Five seconds later, a new window is opened and new measurements on all the identified UMTS cells are performed with the possibility of filtering the measurement taken on the new cell in f0 identified five seconds earlier.
[0032] FIG. 2 illustrates a second or variant embodiment of the invention in which the periods Tp of twenty seconds are not subdivided into measurement subperiods of equal durations. In this case, the measurements are performed every twenty seconds in time windows 14. An advantage of this variation comes from the fact that the measurements are performed in a more spaced apart fashion and thus the mobile terminal in GSM mode in the idle state is awakened less frequently. This leads to better management of the energy of the battery.
[0033] As in the first embodiment, when a new cell is identified as indicated by arrow 16, and if this cell satisfies the reselection criterion defined in the specifications [3GPP 05.08 Sections 6.6.5], it is measured again, as indicated by arrow 18, five seconds after it becomes better. In the same way as in the first embodiment, the terminal simultaneously and on the same carrier frequencies performs in the interval 20 measurements on all the other UMTS cells already identified in order to make sure that none of them has become better in the meantime.
[0034] In the two embodiments, the method allows for periodical allocation of two types of windows, one for performing measurements and the other for trying to identify new cells. This method further allows for filtering the measurements once every five seconds, and modifying the rhythm of taking measurements from five seconds to twenty seconds.
[0035] In the two embodiments, the terminal alternates the phases of identifying new cells once every twenty seconds for each carrier frequency in the list given by the network to the mobile terminal. However, the terminal may perform identification of cells in the various frequencies during the same period of identification Tp.
[0037] Mobile terminal 30 is a GSM-UMTS dual mode mobile terminal and has antenna 32, RF signal processor 34 connected to antenna 32, measuring unit 36 for periodically performing a series of procedures of identifying UMTS cells and a series of intersystem measurements on the identified cells, and phone unit 38 which realizes general functions of a cellular phone such as dialing and voice communication. Measuring unit 36 and phone unit 38 are connected to RF signal processor 34. Especially, measuring unit 36 has allocating unit 40 for allocating, every 20 seconds, a time window for identifying new UMTS cells among a plurality of UMTS cells indicated to mobile terminal 30 by the network, simultaneous measuring unit 42 for simultaneously performing, every five seconds, measurements on the UMTS cells already identified belonging to the same carrier frequency, and confirmation measurement unit 44 for performing a confirmation measurement on each new cell identified and satisfying a predefined reselection criterion. Allocating unit 40 allocates the time windows so that the time windows being alternately assigned to the various carrier frequencies used in the cells of the network. Confirmation measurement unit 44 performs the confirmation measurement at most five seconds after the identification of that new cell.
1. A method of reselecting a cell by a mobile terminal in idle mode in a GSM cell in
a cellular telecommunication network in which the network sends to the terminal a
list containing information with regard to the UMTS cells to be identified, and the
terminal periodically performs a series of procedures of identifying said cells and
a series of intersystem measurements on the identified cells,
wherein, between two successive procedures of identification, the terminal performs a series of procedures of measurement whose duration is fixed so that total duration for performing a procedure of identification and the subsequent series of procedures of measurement is less than 25 seconds,
wherein the terminal allocates, every 20 seconds, a time window for identifying new UMTS cells among a plurality of UMTS cells indicated to the mobile terminal by the network, the time windows being alternately assigned to the various carrier frequencies used in the cells of the network and the terminal simultaneously performs, every five seconds, measurements on the UMTS cells already identified belonging to the same carrier frequency.
wherein, between two successive procedures of identification, the terminal performs a series of procedures of measurement whose duration is fixed so that total duration for performing a procedure of identification and the subsequent series of procedures of measurement is less than 25 seconds,
wherein the terminal allocates, every 20 seconds, a time window for identifying new UMTS cells among a plurality of UMTS cells indicated to the mobile terminal by the network, the time windows being alternately assigned to the various carrier frequencies used in the cells of the network and the terminal simultaneously performs, every five seconds, measurements on the UMTS cells already identified belonging to the same carrier frequency.
2. The method according to claim 1, further comprising the steps of: comparing the measurements
performed for each cell against a predefined selection criterion, and reselecting
the UMTS cell according to a result of the comparing step.
3. The method according to claim 2, further comprising the step of performing the measurements
on sliding time windows so as to obtain a mean value of said measurements.
4. The method according to claim 1, wherein the terminal performs a confirmation measurement
at the end of a maximum duration of five seconds at most following the identification
of a new cell.
5. The method according to claim 4, further comprising the steps of comparing the measurements
performed for each cell against a predefined selection criterion, and reselecting
the UMTS cell according to a result of the comparing step.
6. The method according to claim 5, further comprising the step of performing the measurements
on sliding time windows so as to obtain a mean value of said measurements.
7. The method according to claim 1, wherein the intersystem measurements and the procedures
of identification of cells are performed with the same frequency.
8. The method according to claim 7, further comprising the steps of: comparing the measurements
performed for each cell against a predefined selection criterion, and reselecting
the UMTS cell according to a result of the comparing step.
9. The method according to claim 8, further comprising the step of performing the measurements
on sliding time windows so as to obtain a mean value of said measurements.
10. The method according to claim 1, wherein the intersystem measurements are performed
with a frequency that is higher than the one for the procedures of identification.
11. The method according to claim 10, further comprising the steps of:
comparing the measurements performed for each cell against a predefined selection criterion, and reselecting the UMTS cell according to a result of the comparing step.
12. The method according to claim 11, further comprising a step that consists in performing
the measurements on sliding time windows so as to obtain a mean value of said measurements.
13. A GSM-UMTS dual mode mobile terminal in idle mode in a GSM cell comprising: means
for periodically performing a series of procedures of identifying UMTS cells and a
series of intersystem measurements on the identified cells; means for allocating,
every 20 seconds, a time window for identifying new UMTS cells among a plurality of
UMTS cells indicated to the mobile terminal by the network, said time windows being
alternately assigned to various carrier frequencies used in the cells of the network;
and means for simultaneously performing, every five seconds, measurements on the UMTS
cells already identified belonging to the same carrier frequency.
14. The mobile terminal according to claim 13, further comprising means for performing
a confirmation measurement on each new cell identified and satisfying a predefined
reselection criterion, said confirmation measurement being performed at most five
seconds after the identification of that new cell.
1. Verfahren zum Wiederauswählen einer Zelle durch ein mobiles Endgerät im Leerlaufbetrieb
in einer GSM-Zelle in einem zellularen Telekommunikationsnetz, in dem das Netz dem
Endgerät eine Liste enthaltend Informationen bezogen auf die zu identifizierenden
UMTS-Zellen sendet und das Endgerät periodisch eine Reihe von Prozeduren des Identifizierens
der Zellen und eine Reihe von Intersystemmessungen an den identifizierten Zellen durchführt,
wobei das Endgerät zwischen zwei aufeinanderfolgenden Identifikationsprozeduren eine Reihe von Messprozeduren durchführt, deren Dauer festgelegt ist, so dass die Gesamtdauer zum Durchführen einer Identifikationsprozedur und der anschließenden Reihe von Messprozeduren weniger als 25 Sekunden beträgt,
wobei das Endgerät alle 20 Sekunden ein Zeitfenster zum Identifizieren neuer UMTS-Zellen unter einer Mehrzahl UMTS-Zellen zuweist, die dem mobilen Endgerät durch das Netz angegeben werden, wobei die Zeitfenster abwechselnd den verschiedenen Trägerfrequenzen zugewiesen werden, die in den Zellen des Netzes verwendet werden, und das Endgerät gleichzeitig alle fünf Sekunden Messungen an den bereits identifizierten UMTS-Zellen durchführt, die zur selben Trägerfrequenz gehören.
wobei das Endgerät zwischen zwei aufeinanderfolgenden Identifikationsprozeduren eine Reihe von Messprozeduren durchführt, deren Dauer festgelegt ist, so dass die Gesamtdauer zum Durchführen einer Identifikationsprozedur und der anschließenden Reihe von Messprozeduren weniger als 25 Sekunden beträgt,
wobei das Endgerät alle 20 Sekunden ein Zeitfenster zum Identifizieren neuer UMTS-Zellen unter einer Mehrzahl UMTS-Zellen zuweist, die dem mobilen Endgerät durch das Netz angegeben werden, wobei die Zeitfenster abwechselnd den verschiedenen Trägerfrequenzen zugewiesen werden, die in den Zellen des Netzes verwendet werden, und das Endgerät gleichzeitig alle fünf Sekunden Messungen an den bereits identifizierten UMTS-Zellen durchführt, die zur selben Trägerfrequenz gehören.
2. Verfahren nach Anspruch 1, weiterhin umfassend folgende Schritte: Vergleichen der
für jede Zelle durchgeführten Messungen mit einem vorab definierten Auswahlkriterium
und Wiederauswählen der UMTS-Zelle gemäß einem Ergebnis des Vergleichsschritts.
3. Verfahren nach Anspruch 2, weiterhin umfassend den Schritt des Durchführens der Messungen
in gleitenden Zeitfenstern, um einen Mittelwert der Messungen zu erhalten.
4. Verfahren nach Anspruch 1, wobei das Endgerät am Ende einer maximalen Dauer von höchstens
fünf Sekunden nach der Identifizierung einer neuen Zelle eine Bestätigungsmessung
durchführt.
5. Verfahren nach Anspruch 4, weiterhin umfassend folgende Schritte: Vergleichen der
für jede Zelle durchgeführten Messungen mit einem vorab definierten Auswahlkriterium
und Wiederauswählen der UMTS-Zelle gemäß einem Ergebnis des Vergleichsschritts.
6. Verfahren nach Anspruch 5, weiterhin umfassend den Schritt des Durchführens der Messungen
in gleitenden Zeitfenstern, um einen Mittelwert der Messungen zu erhalten.
7. Verfahren nach Anspruch 1, wobei die Intersystemmessungen und die Identifikationsprozeduren
von Zellen mit der gleichen Frequenz durchgeführt werden.
8. Verfahren nach Anspruch 7, weiterhin umfassend folgende Schritte: Vergleichen der
für jede Zelle durchgeführten Messungen mit einem vorab definierten Auswahlkriterium
und Wiederauswählen der UMTS-Zelle gemäß einem Ergebnis des Vergleichsschritts.
9. Verfahren nach Anspruch 8, weiterhin umfassend den Schritt des Durchführens der Messungen
in gleitenden Zeitfenstern, um einen Mittelwert der Messungen zu erhalten.
10. Verfahren nach Anspruch 1, wobei die Intersystemmessungen mit einer Frequenz durchgeführt
werden, die höher als die für die Identifikationsprozeduren ist.
11. Verfahren nach Anspruch 10, weiterhin umfassend folgende Schritte: Vergleichen der
für jede Zelle durchgeführten Messungen mit einem vorab definierten Auswahlkriterium
und Wiederauswählen der UMTS-Zelle gemäß einem Ergebnis des Vergleichsschritts.
12. Verfahren nach Anspruch 11, weiterhin umfassend einen Schritt, der aus dem Durchführen
der Messungen in gleitenden Zeitfenstern besteht, um einen Mittelwert der Messungen
zu erhalten.
13. Mobiles GSM-UMTS-Dualmodus-Endgerät im Leerlaufbetrieb in einer GSM-Zelle, umfassend:
Mittel, um periodisch eine Reihe von Prozeduren des Identifizierens von UMTS-Zellen
und eine Reihe von Intersystemmessungen an den identifizierten Zellen durchzuführen;
Mittel, um alle 20 Sekunden ein Zeitfenster zum Identifizieren neuer UMTS-Zellen unter
einer Mehrzahl UMTS-Zellen zuzuweisen, die dem mobilen Endgerät durch das Netz angegeben
werden, wobei die Zeitfenster den verschiedenen Trägerfrequenzen, die in den Zellen
des Netzes verwendet werden, abwechselnd zugewiesen werden; und Mittel, um gleichzeitig
alle fünf Sekunden Messungen an den bereits identifizierten UMTS-Zellen durchzuführen,
die zur selben Trägerfrequenz gehören.
14. Mobiles Endgerät nach Anspruch 13, weiterhin umfassend Mittel zum Durchführen einer
Bestätigungsmessung an jeder neuen Zelle, die identifiziert ist und ein vorab definiertes
Wiederauswahlkriterium erfüllt, wobei die Bestätigungsmessung höchstens fünf Sekunden
nach der Identifizierung der neuen Zelle durchgeführt wird.
1. Procédé de resélection d'une cellule par un terminal mobile en mode inactif dans une
cellule GSM dans un réseau de télécommunication cellulaire dans lequel le réseau envoie
au terminal une liste contenant des informations en ce qui concerne les cellules UMTS
à identifier, et le terminal effectue périodiquement une série de procédures d'identification
desdites cellules et une série de mesures intersystèmes sur les cellules identifiées,
dans lequel, entre deux procédures d'identification successives, le terminal effectue une série de procédures de mesure dont la durée est fixée de sorte que la durée totale pour effectuer une procédure d'identification et la série de procédures de mesure subséquente soit inférieure à 25 secondes,
dans lequel le terminal alloue, toutes les 20 secondes, une fenêtre temporelle pour identifier de nouvelles cellules UMTS parmi une pluralité de cellules UMTS indiquées au terminal mobile par le réseau, les fenêtres temporelles étant assignées alternativement aux diverses fréquences porteuses utilisées dans les cellules du réseau et le terminal effectue simultanément, toutes les cinq secondes, des mesures sur les cellules UMTS déjà identifiées appartenant à la même fréquence porteuse.
dans lequel, entre deux procédures d'identification successives, le terminal effectue une série de procédures de mesure dont la durée est fixée de sorte que la durée totale pour effectuer une procédure d'identification et la série de procédures de mesure subséquente soit inférieure à 25 secondes,
dans lequel le terminal alloue, toutes les 20 secondes, une fenêtre temporelle pour identifier de nouvelles cellules UMTS parmi une pluralité de cellules UMTS indiquées au terminal mobile par le réseau, les fenêtres temporelles étant assignées alternativement aux diverses fréquences porteuses utilisées dans les cellules du réseau et le terminal effectue simultanément, toutes les cinq secondes, des mesures sur les cellules UMTS déjà identifiées appartenant à la même fréquence porteuse.
2. Procédé selon la revendication 1, comprenant en outre les étapes consistant à : comparer
les mesures effectuées pour chaque cellule par rapport à un critère de sélection prédéfini,
et resélectionner la cellule UMTS selon un résultat de l'étape de comparaison.
3. Procédé selon la revendication 2, comprenant en outre l'étape consistant à effectuer
les mesures sur des fenêtres temporelles glissantes afin d'obtenir une valeur moyenne
desdites mesures.
4. Procédé selon la revendication 1, dans lequel le terminal effectue une mesure de confirmation
à la fin d'une durée maximale de cinq secondes au plus après l'identification d'une
nouvelle cellule.
5. Procédé selon la revendication 4, comprenant en outre les étapes consistant à : comparer
les mesures effectuées pour chaque cellule par rapport à un critère de sélection prédéfini,
et resélectionner la cellule UMTS selon un résultat de l'étape de comparaison.
6. Procédé selon la revendication 5, comprenant en outre l'étape consistant à effectuer
les mesures sur des fenêtres temporelles glissantes afin d'obtenir une valeur moyenne
desdites mesures.
7. Procédé selon la revendication 1, dans lequel les mesures intersystèmes et les procédures
d'identification de cellules sont effectuées avec la même fréquence.
8. Procédé selon la revendication 7, comprenant en outre les étapes consistant à : comparer
les mesures effectuées pour chaque cellule par rapport à un critère de sélection prédéfini,
et resélectionner la cellule UMTS selon un résultat de l'étape de comparaison.
9. Procédé selon la revendication 8, comprenant en outre l'étape consistant à effectuer
les mesures sur des fenêtres temporelles glissantes afin d'obtenir une valeur moyenne
desdites mesures.
10. Procédé selon la revendication 1, dans lequel les mesures intersystèmes sont effectuées
avec une fréquence qui est supérieure à celle pour les procédures d'identification.
11. Procédé selon la revendication 10, comprenant en outre les étapes consistant à : comparer
les mesures effectuées pour chaque cellule par rapport à un critère de sélection prédéfini,
et resélectionner la cellule UMTS selon un résultat de l'étape de comparaison.
12. Procédé selon la revendication 11, comprenant en outre une étape qui consiste à effectuer
les mesures sur des fenêtres temporelles glissantes afin d'obtenir une valeur moyenne
desdites mesures.
13. Terminal mobile bimode GSM-UMTS en mode inactif dans une cellule GSM comprenant :
des moyens pour effectuer périodiquement une série de procédures d'identification
de cellules UMTS et une série de mesures intersystèmes sur les cellules identifiées
; des moyens pour allouer, toutes les 20 secondes, une fenêtre temporelle pour identifier
de nouvelles cellules UMTS parmi une pluralité de cellules UMTS indiquées au terminal
mobile par le réseau, lesdites fenêtres temporelles étant assignées alternativement
à diverses fréquences porteuses utilisées dans les cellules du réseau ; et des moyens
pour effectuer simultanément, toutes les cinq secondes, des mesures sur les cellules
UMTS déjà identifiés appartenant à la même fréquence porteuse.
14. Terminal mobile selon la revendication 13, comprenant en outre des moyens pour effectuer
une mesure de confirmation sur chaque nouvelle cellule identifiée et satisfaisant
à un critère de resélection prédéfini, ladite mesure de confirmation étant effectuée
au plus cinq secondes après l'identification de cette nouvelle cellule.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description
Non-patent literature cited in the description
- Digital cellular telecommunications system (Phase 2);Radio subsystem link control (GSM 05.08EUROPEAN TELECOMMUNICATION STANDARD, XX, XX, 1997, 1-37 [0009]