Neighborhood list assimilation for cell-based microsystem

• US 6,421,328 B1
• Filed: 05/28/1998
• Issued: 07/16/2002
• Est. Priority Date: 09/04/1997
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Larribeau, Scott, Duong, Luong Duy
• Primary Examiner(s): RAO, SEEMA SRINIVAS
• Application Number:
  US09/086,299
• Time in Patent Office: 1,510 Days
• Field of Search: 370/329, 370/331, 370/332, 370/330, 370/333, 370/335, 370/338, 370/343, 370/431, 455/414, 455/438, 455/440, 455/442, 455/436, 455/444, 455/447, 455/63, 455/445, 455/434, 455/450, 455/509, 455/511
• US Class Current: 370/329
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A method for assembling a microsystem neighbor list that defines control channel usage within a common operational band used by the microsystem, the overlying macrosystem and any computer microsystems. Such a method can be implemented by a frequency planning controller within the microsystem, the microsystem itself or, in the case of the computer-controlled microsystem, in a computer program product defining such method. Assembly of the microsystem neighbor list includes defining preferred and non-preferred members, wherein the preferred members of the macrosystem neighbor list include at least one control channel identified within the common operational band which determined to be available for use by the microsystem. The non-preferred members of the microsystem neighbor list will include control channels being used by adjacent macrocells of the overlying microsystem, or any competing microsystems. The assembled microsystem neighbor list may be broadcast throughout the service area of the microsystem in order to apprise all registered mobiles of active/backup control channel information (thereby improving control channel allocation flexibility control channel recovery operations), as well as control channel information for the competing Microsystems or adjacent macrocells (to improve switchover to such systems when requested by a mobile operator). Other disclosed aspects include ongoing maintenance through verification of preferred and non-preferred members of the macrosystem neighbor list.

Claims

1. A method for assembling a microsystem neighbor list for a cell-based microsystem operating within an overlying macrosystem, comprising the steps of:

acquiring a macrosystem neighbor list for the overlying macrosystem;

determining an available control channel within an operational band of the overlying macrosystem for use by the microsystem;

designating the available control channel as a preferred member of the microsystem neighbor list and designating all preferred members of the macrosystem neighbor list as non-preferred members of the microsystem neighbor list; and

broadcasting the microsystem neighbor list within the microsystem via the available control channel.

2. The method of claim 1, wherein the macrosystem neighbor list comprises a macrocell neighbor list issued by a macrocell of the macrosystem, the macrocell being geographically proximate the microsystem.

3. The method of claim 2, wherein the microsystem resides at least partly within a service area of the macrocell.

4. The method of claim 1, wherein said determining step comprises the steps of:

scanning a first set of candidate channels within the operational band of the overlying macrosystem;

measuring a signal characteristic for each scanned candidate channel;

comparing the measured signal characteristics to obtain a second set of candidate channels whose measured signal characteristics do not exceed a tolerance threshold; and

selecting the available control channel from the second set of scanned candidate channels.

5. The method of claim 4, wherein the signal characteristic is a perceived RSSI measurement.

6. The method of claim 4, wherein the first set of candidate channels comprises any frequency pair defined by the operational band of the overlying macrosystem.

7. The method of claim 4, wherein the first set of candidate channels is selected from a plurality of control channels defined within the operational band of the overlying macrosystem.

8. The method of claim 4, wherein said designating step comprises designating each of the second set of candidate channels as preferred members of the microsystem neighbor list.

9. The method of claim 1, wherein said determining step comprises selecting an available control channel from a set of candidate channels specified by the acquired macrosystem neighbor list.

10. The method of claim 1, wherein

the microsystem is a PSP-POF compatible microsystem;

and wherein said broadcasting step comprises the steps of;

converting the microsystem neighbor list into a PSP-POF table, all preferred members of the microsystem neighbor list being converted into PSP entries of the PSP-POF table, all non-preferred members of the microsystem neighbor list being converted into POF entries of the PSP-POF table; and

broadcasting the PSP-POF table to at least one mobile registered on the microsystem via an active one of the preferred members of the microsystem neighbor list.

11. The method of claim 10, wherein the microsystem is an IS-136 compliant cellular microsystem.

12. The method of claim 1, wherein

the microsystem neighbor list comprises plural preferred members;

and wherein the method further comprises the steps of;

designating a first one of the preferred members of the microsystem neighbor list as an active control channel for the microsystem;

measuring a signal characteristic of the active control channel;

determining whether the measured signal characteristic exceeds a predefined error threshold indicating a likelihood of co-channel interference; and

designating another one of the preferred members of the microsystem neighbor list as the active control channel when it is determined that the measured signal characteristic exceeds the error threshold.

13. The method of claim 12, further comprising the step of removing the first one of the preferred members from the microsystem neighbor list when it is determined that the measured signal characteristic exceeds the error threshold.

14. The method of claim 13, further comprising the steps of:

determining another available control channel within an operational band of the overlying macrosystem; and

designating the another available control channel as a preferred member of the microsystem neighbor list.

15. The method of claim 1, further comprising the step of verifying all non-preferred members of the microsystem neighbor list.

16. A frequency planning controller for a cell-based microsystem operating within an overlying macrosystem, comprising:

means for acquiring a macrosystem neighbor list for the overlying macrosystem;

means for determining an available control channel within an operational band of the overlying macrosystem for use by the microsystem;

means for designating the available control channel as a preferred member of a microsystem neighbor list;

means for designating all preferred members of the macrosystem neighbor list as non-preferred members of the microsystem neighbor list; and

means for uploading the microsystem neighbor list to the microsystem.

17. A microsystem, comprising:

the frequency planning controller of claim 16; and

a base station responsive to said frequency planning controller uploading means for broadcasting the uploaded microsystem neighbor list within a service area of the microsystem.

18. A computer-readable storage medium tangibly embodying computer-readable program code executable by a computer to perform method steps for assembling a microsystem neighbor list for a cell-based microsystem operating within an overlying macrosystem, said method steps comprising:

acquiring a macrosystem neighbor list for the overlying macrosystem;

determining an available control channel within an operational band of the overlying macrosystem for use by the microsystem;

designating the available control channel as a preferred member of the microsystem neighbor list and designating all preferred members of the macrosystem neighbor list as non-preferred members of the microsystem neighbor list; and

directing the microsystem to broadcast the microsystem neighbor list.