Cell selection in mobile communications
View Patent ↗Mobile user equipment for use in a cellular communications environment performs an improved cell selection on transitions out of a connected mode state. The transitions might be from one connected mode state to another or from a connected mode state to idle mode. The improvement in cell selection lies in assembling the list of candidate cells prior to cell selection. In the prior art, the list of candidate cells would usually be restricted to the serving cell or active cells supporting communication between the equipment and the network prior to transition. In embodiments of the invention, the list might comprise cells which are not the serving cell or which are outside the active set, for example a network-preferred cell or cells neighbouring the serving cell or cells of the active set.
1. A method to select a cell in a mobile communications equipment (MCE) when transitioning from a connected mode state to an idle mode state, the MCE configurable for use in a cellular network, the method comprising:
beginning state transition activity, the MCE currently in the connected mode state;
identifying a set of UMTS-based candidate cells, wherein at least one of the set of candidate cells is a cell which is not currently supporting the first connected mode state;
storing information comprising power measurement data relating to a plurality of candidate cells which are not currently supporting the connected mode state arising from past data gathering by the MCE, the information gathered previous to state transition activity;
selecting a candidate cell from the identified set of candidate cells that includes the at least one cell which is not currently supporting the connected mode state based at least in part on the power measurement data; and
transitioning to an idle mode state from the connected mode state.
2. The method of claim 1 wherein said at least one of the candidate cells which is not currently supporting the connected mode state is a cell identified to the MCE by a network.
3. The method of claim 1 wherein said at least one of the candidate cells which is not currently supporting the connected mode state is a cell neighboring a cell supporting the connected mode state.
4. The method of claim 1 where the connected mode state comprises one of Cell_DCH, Cell_FACH, Cell_PCH and URA_PCH.
5. The method of claim 1 where the identified candidate cell set comprises active cell(s) used to support the connected mode state.
6. The method of claim 1 where the identified candidate cell set comprises the serving cell used to support the connected mode state.
7. A mobile communications equipment (MCE) configured for use in a cellular network, comprising:
a processor and operating environment configured to run software processes, the software processes configured to enable the MCE to transition from a connected mode state to an idle mode state, and to determine a set of UMTS-based candidate cells, wherein at least one of the set of candidate cells is a cell which is not currently supporting the connected mode state, and further configured to store information comprising power measurement data with respect to a plurality of candidate cells of the candidate cell set which are not currently supporting the connected mode state, the information gathered previous to the state transition and to select a candidate cell from the identified set of candidate cells that includes the at least one cell which is not currently supporting the connected mode state and based at least in part upon the power measurement data and to use the selected member when transitioning to the idle mode state from the connected mode state.
8. The MCE of claim 7 wherein the at least one of the candidate cells which is not currently supporting the connected mode state is a cell identified to the MCE by a network.
9. The MCE of claim 7 wherein the at least one of the candidate cells which is not currently supporting the connected mode state is a cell neighboring a cell supporting the connected mode state.
10. The MCE of claim 7 where the connected mode state comprises one of Cell_DCH, Cell_FACH, Cell_PCH and URA_PCH.
11. The MCE of claim 7 where the candidate cell set comprises active cell(s) used to support the connected mode state.
12. The MCE of claim 7 where the candidate cell set comprises the serving cell used to support the connected mode state.
13. A method to select a cell in a mobile communications equipment (MCE) when transitioning from a first connected mode state to a second connected mode state, the MCE configurable for use in a cellular network, the method comprising:
beginning state transition activity, the MCE currently in the first connected mode state;
identifying a set of UMTS-based candidate cells, wherein at least one of the candidate cells is a cell which is not currently supporting the first connected mode state;
storing information comprising power measurements with respect to a plurality of candidate cells of the identified candidate set relating to a plurality of candidate cells of the candidate cell set which are not currently supporting the first connected mode state arising from past data gathering by the MCE and corresponding to the same cell;
selecting a candidate cell from the identified set of candidate cells that includes the at least one cell which is not currently supporting the connected mode state and based at least in part on the power measurements; and
transitioning to the second connected mode from the first connected mode state using the selected candidate cell, where the first and second connected mode states are, each, one of: Cell_FACH, Cell_PCH, and URA_PCH.
14. The method of claim 13 wherein said at least one of the candidate cells which is not currently supporting the first connected mode state is a cell identified to the MCE by a network.
15. The method of claim 13 wherein said at least one of the candidate cells which is not currently supporting the first connected mode state is a cell neighboring a cell supporting the first connected mode state.
16. The method of claim 13 where the candidate cell set comprises active cell(s) used to support the first connected mode state.
17. The method of claim 13 where the candidate cell set comprises the serving cell used to support the first connected mode state.
18. A mobile communications equipment (MCE) configured for use in a cellular network, comprising:
a processor and operating environment configured to run software processes, the software processes configured to enable the MCE to transition from a first connected mode state to a second connected mode state to store information comprising power measurements with respect to a plurality of candidate cells of the identified candidate cell set, the information gathered previous to the state transition, and to determine a set of UMTS-based candidate cells wherein at least one of the set of candidate cells is a cell which is not currently supporting the first connected mode state, and further configured to select a candidate cell from the identified set of candidate cells that includes the at least one cell which is not currently supporting the connected mode state and based at least in part upon the power measurement data and to use the selected member when transitioning to the second connected mode state from the first connected mode state where the first and second connected mode states are, each, one of: Cell_FACH, Cell_PCH, and URA_PCH.
19. The MCE of claim 18 wherein the at least one of the candidate cells which is not currently supporting the first connected mode state is a cell identified to the MCE by a network.
20. The MCE of claim 18 wherein the at least one of the candidate cells which is not currently supporting the first connected mode state is a cell neighboring a cell supporting the first connected mode state.
21. The MCE of claim 18 where the candidate cell set comprises active cell(s) used to support the first connected mode state.
22. The MCE of claim 18 where the candidate cell set comprises the serving cell used to support the first connected mode state.