Method combining entries from multiple neighbor cell lists to obtain an updated list for a subscriber device

• US 6,201,968 B1
• Filed: 03/05/1998
• Issued: 03/13/2001
• Est. Priority Date: 03/05/1998
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Alterman, Steven S., Melgarejo, Orestes G., Ostroff, Jeff L.
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): Persino, Raymond B
• Application Number:
  US09/035,140
• Time in Patent Office: 1,104 Days
• Field of Search: 455/436, 455/437, 455/438, 455/439, 455/440, 455/441, 455/442, 455/443, 455/444, 455/422, 455/450, 455/451, 455/452, 455/453, 455/446, 455/456, 455/509, 455/512, 455/513, 455/514, 455/515, 370/329, 370/338, 370/331, 370/332
• US Class Current: 455/436
• CPC Class Codes: H04W 8/183 Processing at user equipment or user record carrier
• CPC Class Codes: H04W 8/245 from a network towards a terminal

Abstract

A subscriber unit (405) operating within a radio communication system (600) supplements neighbor list information received from a cell site (428), when that cell site (428) is expected to provide inadequate neighbor cell list information. When the subscriber unit (405) obtains a new neighbor cell list (442) from the cell site (428), it determines whether characteristics of the cell site (428) is such that the new neighbor cell list (442) does not adequately reflect available neighboring cell sites. Such a condition is presumed to exist for a cell site designated as a high site. In such cases, the subscriber unit combines entries from its current neighbor cell list (451) with entries from the new neighbor cell list (442) obtained from the cell site to generate a supplemented neighbor cell list (652). The supplemented neighbor cell list (652) is used to monitor potential server sites, and to make hand-over decisions.

Claims

1. In a radio communication device, a method comprising the steps of:

establishing affiliation with a server site selected from a current neighbor cell list stored at the radio communication device;

downloading a new neighbor cell list from the server site;

determining whether the new neighbor cell list downloaded needs to be supplemented based on a particular characteristic of the server site;

when the new neighbor cell list needs to be supplemented, replacing the current neighbor cell list with a list derived from a combination of entries from the current neighbor cell list and the new neighbor cell list; and

when the new neighbor cell list does not need to be supplemented, replacing the current neighbor cell list with the new neighbor cell list.

2. The method of claim 1, wherein the step of determining whether the new neighbor cell list needs to be supplemented, comprises the step of determining that the new neighbor cell list needs to be supplemented when the server site is designated a high site.

3. In a radio communication system having a subscriber unit and multiple cell sites, including a particular cell site having a downloadable neighbor cell list containing entries of cell data for neighboring cell sites, the subscriber unit having a previously obtained neighbor cell list, a method comprising the steps of:

establishing affiliation between the subscriber unit and the particular cell site;

determining whether the subscriber unit needs a modified neighbor cell list based on a particular designation for the particular cell site;

when the subscriber unit needs a modified neighbor cell list, replacing the previously obtained neighbor cell list at the subscriber unit with a new list derived from a combination of entries from the previously obtained neighbor cell list and the downloadable neighbor cell list; and

when the subscriber unit does not need a modified neighbor cell list, replacing the previously obtained neighbor cell list with the downloadable neighbor cell list.

4. The method of claim 3, wherein the step determining whether the subscriber unit needs a modified neighbor cell list, comprises the step of determining that the subscriber unit needs a modified neighbor cell list when the particular cell site has a designation indicating wide area coverage when compared to other cell sites.

5. The method of claim 3, wherein the step determining whether the subscriber unit needs a modified neighbor cell list, comprises the step of determining that the subscriber unit needs a modified neighbor cell list when the particular cell site is designated as a high site.

6. The method of claim 5, wherein the step determining whether the subscriber unit needs a modified neighbor cell list, comprises the step of receiving, by the subscriber unit, a parameter from the particular cell site over a control channel, which parameter indicates a high site.

7. The method of claim 3, wherein the step of replacing the previously obtained neighbor cell list at the subscriber unit with a new list, comprises the step of combining entries representing recently used cell sites from the previously obtained neighbor cell list with entries from the downloadable neighbor cell list to form the new list.

8. The method of claim 3, wherein the step of replacing the previously obtained neighbor cell list at the subscriber unit with a new list, comprises the step of combining all entries from the previously obtained neighbor cell list with all entries from the downloadable neighbor cell list to form the new list.

9. In a radio communication system having a subscriber unit, a method at the subscriber unit comprising the steps of:

affiliating with a first server site;

downloading a first neighbor cell list from the first server site;

switching affiliation from the first server site to a second server site using information from the first neighbor cell list;

determining whether the second server site has a high site classification;

downloading a second neighbor cell list from the second server site; and

replacing the first neighbor cell list with a new list containing a combination of entries from the first neighbor cell list and the second neighbor cell list when the second server site has a high site classification.

10. The method of claim 9, wherein the new list contains all of the entries from the second neighbor cell list but only some of the entries from the first neighbor cell list.

11. The method of claim 9, wherein the new list contains all of the entries from the second neighbor cell list and all of the entries from the first neighbor cell list.

12. The method of claim 9, wherein the step determining whether the second server site has a high site classification, comprises the step of receiving a parameter from the second server site over a control channel, which parameter indicates that the second server site is a high site.

13. In a radio communication system having a subscriber unit and a plurality of cell sites, a method at the subscriber unit comprising the steps of:

obtaining a neighbor cell list from a particular cell site;

determining whether a condition exists in which the neighbor cell list does not adequately reflect available neighboring cell sites;

combining entries from the neighbor cell list with entries from at least one other neighbor cell list to obtain an updated neighbor cell list, when the condition exists; and

making hand-over decisions using the updated neighbor cell list.

14. The method of claim 13, wherein the at least one other neighbor cell list comprise a previously used neighbor cell list.