Method of allocating frequency bands to different cells, and TDMA cellular radio system

• US 6,233,229 B1
• Filed: 09/16/1996
• Issued: 05/15/2001
• Est. Priority Date: 11/28/1994
• Status: Expired due to Fees

• Current Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Gandini, Giulio, Jolma, Petri, Ranta, Pekka, Honkasalo, Zhichun
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): YAO, KWANG BIN
• Application Number:
  US08/682,659
• Time in Patent Office: 1,702 Days
• Field of Search: 370/328, 370/329, 370/330, 370/332, 370/333, 370/334, 370/336, 370/337, 370/345, 370/347, 370/350, 455/443, 455/444, 455/450, 455/452, 455/454, 455/455, 455/507, 455/509, 455/516, 455/517, 455/62, 455/63, 455/67.3, 455/132, 455/133, 455/134, 455/135
• US Class Current: 370/330
• CPC Class Codes: H04B 7/2615 using hybrid frequency-time division multiple access [FDMA-TDMA]
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]

Abstract

A TDMA cellular radio system and a method of allocating available frequency bands to different cells in a TDMA cellular radio system wherein at least some of the receivers within the system use interference cancellation methods which cancel the effects of co-channel interference in a desired signal. To enable efficient use of interference cancellation and the resulting capacity increase in the system, the frequency bands available for the cellular radio system are allocated to different cells so that groups of adjacent service areas are formed in the system. Each group uses the same frequency band within the service areas, whereby at least one co-channel signal interfering with the desired signal is significantly stronger than other co-channel interfering signals.

Claims

1. A method of allocating available frequency bands to respective ones of the cells in a TDMA cellular radio system by using frequency planning, said method comprising:

at least some receivers within the cellular radio system employing interference cancellation which cancel effects of co-channel interference in a desired signal;

allocating available frequency bands of the cellular radio system to respective ones of the cells so that, in each cell, at least one co-channel signal interfering with the desired signal is significantly stronger than other co-channel interfering signals, the at least one co-channel signal and the desired signal simultaneously carrying user data traffic of at least two different users; and

respective ones of said receivers canceling effects of co-channel interference from respective ones of said other co-channel interfering signals.

2. The method as claimed in claim 1, wherein:

said allocating includes allocating said available frequency bands of said cellular radio system, to respective ones of said cells such that several groups of adjacent service areas are formed in said cellular radio system each group of which employs a respective one of said frequency bands within each of said service areas.

3. The method as claimed in claim 1, wherein:

said allocating includes available frequency bands dividing each cell into two or more sectors by using directional antennas, and using that a respective one of said frequency bands is used in each sector of respective ones of said cells, whereby, in each sector of each cell at least one co-channel signal originating in an adjacent sector of the respective cell and interfering with the desired signal is significantly stronger than the co-channel interfering signals from the others of said cells.

4. The method as claimed in claim 1, wherein:

said allocating includes allocating said frequency bands according to a re-use factor chosen to so low that in each cell, one or more co-channel signals interfering with the desired signal are significantly stronger than the other co-channel interfering signals.

5. The method as claimed in claim 1, wherein:

said allocating includes causing a same time slot of a given one of said frequency bands to be used on two separate connections within a service area of one base station.

6. A method of allocating available frequency bands to respective ones of the cells in a TDMA cellular radio system by using frequency planning, said method comprising:

at least some receivers within the cellular radio system employing interference cancellation which cancel effects of co-channel interference in a desired signal;

allocating available frequency bands of the cellular radio system to respective ones of the cells so that, in each cell, at least one co-channel signal interfering with the desired signal is significantly stronger than other co-channel interfering signals; and

respective ones of said receivers canceling effects of co-channel interference from respective ones of said other co-channel interfering signals, wherein

said allocating includes allocating said available frequency bands such that said cellular radio system comprises a plurality of large macrocells, each having a respective service area and each employing a specific one of said available frequency bands, and such that within the respective said service area of each said macrocell, there are a group of microcells each of which is significantly smaller than the microcell, and using in each of said microcells a respective same frequency band as is being used in the corresponding said macrocell, whereby in each microcell one stronger that the co-channel interfering signals originating in the others of said cells.

7. The method as claimed in claim 6, wherein:

said employing includes receivers of said microcells employing interference cancellation.

8. A method of allocating available frequency bands to respective ones of the cells in a TDMA cellular radio system by using frequency planning, said method comprising:

at least some receivers within the cellular radio system employing interference cancellation which cancel effects of co-channel interference in a desired signal;

allocating available frequency bands of the cellular radio system to respective ones of the cells so that, in each cell, at least one co-channel signal interfering with the desired signal is significantly stronger than other co-channel interfering signals; and

respective ones of said receivers canceling effects of co-channel interference from respective ones of said other co-channel interfering signals, wherein

said allocating includes allocating said available frequency bands such that said cellular radio system consists of adjacent cell groups, which groups each comprise two or more cells, which cells employ, within each cell group a respective same frequency band, whereby, for each cell group, in each cell at least on co-channel signal interfering with the desired signal is significantly stronger than the co-channel interfering signals originating in the others of said cells.

9. The method as claimed in claim 8, wherein:

said allocating includes causing the number of cells in each said cell group to differ cell group-specifically.

10. A TDMA cellular radio system, said system comprising:

in each cell of a plurality of cells, at least one base station communicating with subscriber terminal equipment within a respective service area, said system having a group of frequency bands allocated thereto, said frequency bands being allocated by frequency planning;

a plurality of receivers, at least some of which employ interference cancellation which cancel effects of co-channel interference in a respective desired signal, the at least one co-channel signal and the desired signal simultaneously carrying user data traffic of at least two different users; and

said frequency bands being so allocated that, in each cell of the cellular radio system, at least one co-channel signal interfering with the desired signal is significantly stronger than the other co-channel interfering signals.