Methods and apparatus for performing cell reselection for supporting efficiently hierarchical cell structures
First Claim
1. A method for performing a cell reselection in a system comprised of a hierarchy of cells, wherein cells of one layer of the hierarchy have a size that differs from cells of another layer of the hierarchy, comprising steps of:
- identifying to a user equipment a layer to which individual cells in a neighbor cell list are associated;
when performing neighbor cell measurements for reselection purposes, avoiding a measurement of cells in the list that are larger than a current serving cell unless a Cell Selection (S) parameter falls below a search threshold parameter (Ssearch), and is greater than zero; and
if S is less than or equal to zero, and no cell reselection to a better cell is in process, beginning a measurement of neighbor cells without regard for their hierarchical level.
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Abstract
A method for performing a cell reselection in a system comprised of a hierarchy of cells, wherein cells of one layer of the hierarchy have a size that differs from cells of another layer of the hierarchy. The method includes steps of (a) identifying to a user equipment a layer to which individual cells in a neighbor cell list are associated; (b) when performing neighbor cell measurements for reselection purposes, avoiding a measurement of cells in the list that are larger than a current serving cell unless a Cell Selection (S) parameter falls below a search threshold parameter (Ssearch), and is greater than zero; and (c), if S is less than or equal to zero, and no cell reselection to a better cell is in process, beginning a measurement of neighbor cells without regard for their hierarchical level. If the user equipment has made cell reselection to N different cells on the same hierarchical layer within a time Tmax, the user equipment initiates a reselection procedure for larger neighbor cells. This procedure accommodates user equipment that is moving at a relatively high speed through the cells. If the user equipment locates a larger cell, which fulfills cell reselection criteria Sn>0 and Qn>Qs+Qoffsets,n+Qhyst for a period of time Treselection, cell reselection to the larger cell is made. Furthermore, if the user equipment performs a cell reselection to the larger cell, the user equipment does not attempt to reselect to a smaller cell within a time X, unless an immediate cell evaluation is triggered, wherein the time X can be pre-specified, or can be set by the network.
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Citations
12 Claims
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1. A method for performing a cell reselection in a system comprised of a hierarchy of cells, wherein cells of one layer of the hierarchy have a size that differs from cells of another layer of the hierarchy, comprising steps of:
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identifying to a user equipment a layer to which individual cells in a neighbor cell list are associated;
when performing neighbor cell measurements for reselection purposes, avoiding a measurement of cells in the list that are larger than a current serving cell unless a Cell Selection (S) parameter falls below a search threshold parameter (Ssearch), and is greater than zero; and
if S is less than or equal to zero, and no cell reselection to a better cell is in process, beginning a measurement of neighbor cells without regard for their hierarchical level. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A wireless communication system comprised of a hierarchy of cells, wherein cells of one layer of the hierarchy have a size that differs from cells of another layer of the hierarchy, comprising user equipment for being located within cells of a wireless communication network, said network for identifying to a user equipment a layer to which individual cells in a neighbor cell list are associated, said user equipment being responsive to the identification when performing neighbor cell measurements for reselection purposes for avoiding a measurement of cells in the list that are larger than a current serving cell, unless a Cell Selection (S) parameter falls below a search threshold parameter (Ssearch), and is greater than zero;
- said user equipment being responsive to a condition that if S is less than or equal to zero, and no cell reselection to a better cell is in process, for beginning a measurement of neighbor cells without regard for their hierarchical level.
- View Dependent Claims (8, 9, 10, 11, 12)
Specification
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- Resources
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Current AssigneeNokia Technologies Oy (Nokia Corporation)
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Original AssigneeNokia Corporation
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InventorsKorpela, Sari, Jansen, Kaj
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Primary Examiner(s)Trost, William
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Assistant Examiner(s)Le, Danh C
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Application NumberUS09/730,350Publication NumberTime in Patent Office1,288 DaysField of Search455/449, 455/434, 455/436, 455/443, 455/444, 455/524, 455/525, 455/446US Class Current455/449CPC Class CodesH04W 36/04 Reselecting a cell layer in...
