Apparatus, computer programs and methods for enabling filtering of neighbor cells or frequencies
View Patent ↗A serving cell sends to user equipments (UEs) indications of frequency bands supported by neighbor cells/frequencies, at least one individual neighbor cell/frequency supporting a plurality of frequency bands. The neighbor cells/frequencies are filtered by the UE to retain only those that are indicated to support a frequency band or frequency bands which are also supported by the UE. The sent indications comprise, for each respective neighbor cell/frequency, one absolute radio frequency channel number (ARFCN) associated with the respective neighbor cell/frequency and the frequency band or bands associated with the respective neighbor cell/frequency. Examples are given of various system information blocks for sending the frequency band indications to the UE. In one embodiment they are arranged in an information element IE having an entry for each of the neighbor cells/frequencies and a list of frequency bands for each entry.
1. An apparatus comprising:
a processing system comprising at least one processor and a computer-readable memory storing a program, in which the processing system is constructed and arranged to cause the apparatus at least to:
receive at a user equipment from a serving cell indications of frequency bands supported by respective neighbor cells, said indications comprising for at least one individual neighbor cell one absolute radio frequency channel number (ARFCN) associated with the at least one individual neighbor cell and a plurality of frequency bands associated with the at least one individual neighbor cell;
from the received indications, derive at the user equipment from the indicated one ARFCN and the plurality of frequency bands at least one other ARFCN; and
determine which frequency bands, of at least the one ARFCN and the at least one other ARFCN, are supported by the user equipment and retain the determined frequency bands in a local memory of the user equipment for mobility operations.
2. The apparatus according to claim 1 , in which the indications are received in system information broadcast by the serving cell, and the at least one individual neighbor cell is a neighbor cell to the serving cell.
3. The apparatus according to claim 2 , in which the indications are received in at least one of system information block types 11, 11bis, 12, 19 and 3.
4. The apparatus according to claim 1 , in which the indications are received in system information, in an information element having an entry for each of the neighbor cells and a list of frequency bands for each entry.
5. The apparatus according to claim 1 , in which the indications are received in system information, in an information element having an index and one or more associated frequency bands, in which a value of the index indicates that one or more of the neighbor cells referred to by the index belongs to the one or more frequency bands associated with the index.
6. The apparatus according to claim 1 , wherein the indications are such that each of the neighbor cells supports a plurality of frequency bands.
7. The apparatus according to claim 1 , wherein the user equipment receives the indications from at least one of:
a node B while the user equipment is operating in a universal mobile telecommunications system (UMTS), and
an evolved node B while the user equipment is operating in an evolved universal terrestrial radio access network (EUTRAN).
8. A method comprising:
receiving at a user equipment from a serving cell indications of frequency bands supported by respective neighbor cells, said indications comprising for at least one individual neighbor cell one absolute radio frequency channel number (ARFCN) associated with the at least one individual neighbor cell and a plurality of frequency bands associated with the at least one individual neighbor cell;
from the received indications, deriving at the user equipment from the indicated one ARFCN and the plurality of frequency bands at least one other ARFCN; and
determining which frequency bands, of at least the one ARFCN and the at least one other ARFCN, are supported by the user equipment and retaining the determined frequency bands in a local memory of the user equipment for mobility operations.
9. The method according to claim 8 , in which the indications are received in system information broadcast by the serving cell, and the at least one individual neighbor cell is a neighbor cell to the serving cell.
10. The method according to claim 9 , in which the indications are received in at least one of system information block types 11, 11bis, 12, 19 and 3.
11. The method according to claim 8 , in which the indications are received in system information, in an information element having an entry for each of the neighbor cells and a list of frequency bands for each entry.
12. The method according to claim 8 , in which the indications are received in system information, in an information element having an index and one or more associated frequency bands, in which a value of the index indicates that one or more of the neighbor cells referred to by the index belongs to the one or more frequency bands associated with the index.
13. The method according to claim 8 , wherein the indications are such that each of the neighbor cells supports a plurality of frequency bands.
14. A memory tangibly storing a computer program that is executable by at least one processor, in which the computer program comprises:
code for deriving at least one other absolute radio frequency channel number (ARFCN) from indications received at a user equipment from a serving cell of frequency bands supported by respective neighbor cells, said indications comprising for at least one individual neighbor cell one ARFCN associated with the at least one individual neighbor cell and a plurality of frequency bands associated with the at least one individual neighbor cell; and
code for determining which frequency bands, of at least the one ARFCN and the at least one other ARFCN, are supported by the user equipment and for retaining the determined frequency bands in a local memory of the user equipment for mobility operations.
15. The memory according to claim 14 , in which the indications are received in system information broadcast by the serving cell, and the at least one individual neighbor cell is a neighbor cell to the serving cell.
16. The memory according to claim 15 , in which the indications are received in at least one of system information block types 11, 11bis, 12, 19 and 3.
17. The memory according to claim 14 , in which the indications are received in system information, in an information element having an entry for each of the neighbor cells and a list of frequency bands for each entry.
18. The memory according to claim 14 , in which the indications are received in system information, in an information element having an index and one or more associated frequency bands, in which a value of the index indicates that one or more of the neighbor cells referred to by the index belongs to the one or more frequency bands associated with the index.
19. The memory according to claim 14 , wherein the indications are such that each of the neighbor cells supports a plurality of frequency bands.
20. The memory according to claim 14 , wherein the user equipment receives the indications from at least one of:
a node B while the user equipment is operating in a universal mobile telecommunications system (UMTS), and
an evolved node B while the user equipment is operating in an evolved universal terrestrial radio access network (EUTRAN).