Method and apparatus for enabling a user equipment to use cells having different frequencies
AssigneeNokia Solutions and Networks Oy
InventorsFrank Frederiksen, Troels Emil Kolding
Life of this patent
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Abstract
A method including determining that a user equipment on a first cell having a first frequency is to alternatively or additionally use a second cell having a second different frequency; and searching for a reference signal of said second cell within a window defined with respect to said first cell or a third cell.
Claims16
A method, said method being performed by a user equipment in a communications network comprising a first cell operating on a first frequency, a second cell operating on a second frequency, and a third cell operating on a third frequency, the first and second cells being macro cells, and the third cell being a small cell overlying the first cell and the second cell, the user equipment being in the first cell operating on the first frequency, said method comprising:
- determining whether a handover to or carrier aggregation with the third cell is required;
- searching for a reference signal of said third cell within a time window defined with respect to a first frequency signal of said first cell or a second frequency signal of the second cell,
- wherein, when a time offset between the first cell and the second cell is greater than a threshold, the reference signal comprises pilots defined with a time offset with respect to the first cell and separate pilots defined with the same time offset with respect to the second cell, and
- wherein, when a time offset between the first cell and the second cell is smaller than or equal to the threshold, the reference signal comprises common pilots defined with a time offset with respect to the first cell;
- finding the reference signal;
- and
- using the reference signal to initiate handover to or carrier aggregation with said third cell.
An apparatus, said apparatus being a user equipment in a communications network comprising a first cell operating on a first frequency, a second cell operating on a second frequency, and a third cell operating on a third frequency, the first and second cells being macro cells, and the third cell being a small cell overlying the first cell and the second cell, the user equipment being in the first cell operating on the first frequency, said apparatus comprising:
- at least one processor;
- and
- at least one memory including computer program code, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to perform:
- determine whether a handover to or carrier aggregation with the third cell is required;
- search for a reference signal of said third cell within a time window defined with respect to a first frequency signal of said first cell or a second frequency signal of the second cell,
- wherein, when a time offset between the first cell and the second cell is greater than a threshold, the reference signal comprises pilots defined with a time offset with respect to the first cell and separate pilots defined with the same time offset with respect to the second cell, and
- wherein, when a time offset between the first cell and the second cell is smaller than or equal to the threshold, the reference signal comprises common pilots defined with a time offset with respect to the first cell;
- find the reference signal;
- and
- use the reference signal to initiate handover to or carrier aggregation with said third cell.
An apparatus comprising:
- at least one processor;
- and
- at least one memory including computer program code, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to perform:
- provide a reference signal for a user equipment in a communications network comprising a first cell operating on a first frequency, a second cell operating on a second frequency, and a third cell operating on a third frequency, the first and second cells being macro cells, and the third cell being a small cell overlying the first cell and the second cell, the user equipment being in the first cell operating on the first frequency in the first cell, to use to handover to or perform carrier aggregation with the third cell, said reference signal being provided within the third cell within a time window defined with respect to a first frequency signal of said first cell or the second frequency signal of the second cell,
- wherein, when a time offset between the first cell and the second cell is greater than a threshold, the reference signal comprises pilots defined with a time offset with respect to the first cell and separate pilots defined with the same time offset with respect to the second cell, and
- wherein, when a time offset between the first cell and the second cell is smaller than or equal to the threshold, the reference signal comprises common pilots defined with a time offset with respect to the first cell;
- and
- permitting said user equipment to initiate handover to or carrier aggregation with said third cell.
Dependencies are inferred from the claim text.