Apparatus and method for adaptive dynamic channel assignment in wireless communication networks

• US 5,956,643 A
• Filed: 03/09/1995
• Issued: 09/21/1999
• Est. Priority Date: 01/13/1994
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Benveniste, Mathilde
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/401,387
• Time in Patent Office: 1,657 Days
• Field of Search: 455/33.1, 455/62, 455/63, 455/54.1, 455/54.2, 455/56.1, 455/65, 455/34.1, 455/34.2, 455/67.1, 455/67.3, 455/450, 455/452, 455/455, 379/59, 379/60
• US Class Current: 455/452.1
• CPC Class Codes: H04W 16/04 Traffic adaptive resource partitioning
• CPC Class Codes: H04W 16/06 Hybrid resource partitioning, e.g. channel borrowing
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• CPC Class Codes: H04W 28/26 Resource reservation

Abstract

A channel assignment system assigns channels to various cells by the optimal partitioning of the available radio frequencies into non-overlapping sets, the optimal grouping of co-user cells, and the best assignment of the former to the latter. The objective is the maximization of traffic handling capacity which, given the multitude of cells, is expressed as the maximization of a bottleneck capacity ratio. The capacity ratio for a cell is defined as the ratio of the number of radio frequencies assigned to the cell over the number of radio frequencies needed to meet blocking probability requirements. The solution to attain an optimal non-regular channel assignment is decomposed into two mathematical programs designated a Master Program and a Subprogram. These are solved iteratively with assistance from a channel set augmentation technique implemented between solutions of the Master and Subprogram.

Claims

1. In a wireless communications system having service areas partitioned into a plurality of substantially contiguous cells, wherein another plurality of radio communications channels is available for allocation among said cells, a method for assigning channels to cells comprising the steps of:

computing an assignment of radio channel sets to the cells;

apportioning a set of channels assigned to a first cell between a reserved portion and a free portion;

determining at the time of a channel request from a second cell whether said first cell has channels available from said reserved portion of assigned channels;

making a dynamic determination as to whether at least one of said available reserved channels of said first cell'"'"'s assigned channels will meet interference and system constraints for application in said second cell; and

making a channel from said at least one channel meeting interference and system constraints available for borrowing by said second cell.

2. The method of claim 1 wherein said step of borrowing comprising the further step of:

employing a higher confidence level (or different parameters in the corresponding deterministic equivalent constraints) when determining said second cell can borrow said channel assigned to said first cell.

3. The method of claim 1 comprising the further steps of:

changing said reserved portion of assigned channels to be reserved for said cell.

4. The method of claim 1 comprising the further steps of:

determining if a released channel at the termination of a call is a borrowed channel; and

transferring an existing call on a borrowed channel to said released channel if said released channel is not borrowed.

5. A method of operating a wireless communications system having service areas partitioned into a plurality of substantially contiguous cells, said method comprising the steps of:

determining the available cells and available radio channels for the system;

determining serving signal and interference statistics;

determining interference and system constraints for the cells;

determining existing traffic patterns for the cells;

inputting the cells, channels, serving signal and interference statistics, interference and system constraints, existing traffic patterns and blocking requirements for the cells into a computing device;

computing an assignment of disjoint sets of available radio channels to the cells;

apportioning a set of channels assigned to a first cell between a reserved portion and a free portion;

determining at the time of a channel request from a second cell whether said first cell has channels available from said reserved portion of assigned channels;

making a dynamic determination as to whether at least one of said available reserved channels of said first cell'"'"'s assigned channels will meet interference and system constraints for application in said second cell;

making a channel from said at least one channel meeting interference and system constraints available for borrowing by said second cell; and

tuning a cell radio in said second cell to the said channel assigned to said first cell.

6. The method of claim 5 wherein said step of borrowing comprising the further step of:

employing a higher confidence level (or different parameters in the corresponding deterministic equivalent constraints) when determining said second cell can borrow said channel assigned to said first.

7. The method of claim 5 comprising the further step of:

changing the reserved portion of assigned channels to be reserved for said cell.

8. The method of claim 7 wherein said step of changing occurring in real time.

9. The method of claim 5 comprising the further steps of:

determining if a released channel at the termination of a call is a borrowed channel; and

transferring an existing call on a borrowed channel to said released channel if said released channel is not borrowed.