Multi-level sectorized CDMA communications

• US 6,122,266 A
• Filed: 02/19/1997
• Issued: 09/19/2000
• Est. Priority Date: 02/19/1997
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Lynch, Michael A.
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US08/801,338
• Time in Patent Office: 1,308 Days
• Field of Search: 370/335, 370/342, 370/320, 370/324, 370/331, 370/329, 370/441, 370/334, 375/200, 455/434, 455/446, 455/447, 455/449, 455/450, 455/515, 455/562, 455/436, 455/442, 455/444, 342/381
• US Class Current: 370/335
• CPC Class Codes: H04W 16/00 Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
• CPC Class Codes: H04W 16/24 Cell structures

Abstract

A base station of a code division multiple access (CDMA)-based communications network (e.g., one conforming to the IS-95 standard) is sectorized such that, a first subset of CDMA channels are communicated using a first level of cell-site sectorization and a second subset of CDMA channels, different from the first subset, are communicated using a second level of cell-site sectorization, different from the first level. For example, the first set of CDMA channels may be the pilot and sync channels and the second subset of CDMA channels may be the access, paging, and traffic channels. In one set of implementations, at the first sectorization level, each cell site is omnidirectional (for the first subset of CDMA channels), while, at the second sectorization level, each cell site is divided into two or more sectors (for the second subset of CDMA channels). In this set of implementations, each cell site is assigned one pseudo noise (PN) offset and transmits one pilot channel. In another set of implementations, at the first sectorization level, each cell site is divided into two or more sectors (for the first subset of CDMA channels), while, at the second sectorization level, each sector is further divided into two or more sub-sectors (for the second subset of CDMA channels). In this set of implementations, each sector is assigned one PN offset and each cell site transmits a different pilot channel for each sector. In either case, the present invention is able to provide certain advantages of sectorization (e.g., increased capacity and reduced interference) while reducing certain disadvantages of sectorization (e.g., pilot pollution, handoff processing). Moreover, the present invention can be implemented to support existing remote terminals (e.g., mobile/cellular telephones) having three-finger RAKE receivers.

Claims

1. During non-handoff operations, a method for communicating between a base station and an individual remote terminal of a CDMA-based communications network, comprising the steps of:

(a) communicating between the base station and the individual remote terminal via a first subset of types of CDMA channels at a first sectorization level of a cell-site sectorization scheme; and

(b) simultaneously communicating between the base station and the individual remote terminal via a second subset of types of CDMA channels, different from the first subset, at a second sectorization level of the cell-site sectorization scheme, having a degree of sectorization different from the degree of sectorization of the first sectorization level, wherein;

a cell corresponding to the base station is simultaneously sectorized at (1) the first sectorization level for communications between the base station and the individual remote terminal using the first subset of types of CDMA channels and (2) the second sectorization level for communications between the base station and the individual remote terminal using the second subset of types of CDMA channels;

the types of CDMA channels comprise one or more of pilot, sync, paging, and forward link traffic channels transmitted from the base station to the remote terminal, and one or more of access and reverse link traffic channels transmitted from the remote terminal to the base station;

the first subset comprises one or more of the pilot and sync channels; and

the second subset comprises one or more of the access, paging, forward link traffic, and reverse link traffic channels.

2. The method of claim 1, wherein the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

3. The method of claim 1, wherein the first sectorization level has a lower degree of sectorization than the second sectorization level.

4. The method of claim 3, wherein:

at the first sectorization level, the cell site is omnidirectional;

at the second sectorization level, the cell site is sectorized into two or more sectors; and

one PN offset is assigned to the cell site; and

the cell site transmits signals corresponding to one pilot channel.

5. The method of claim 3, wherein:

at the first sectorization level, the cell site is sectorized into two or more sectors;

at the second sectorization level, each sector is further sectorized into two or more sub-sectors;

one PN offset is assigned to each sector;

each sector transmits signals corresponding to one pilot channel; and

the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

6. A base station of a CDMA-based communications network for communicating with an individual remote terminal during non-handoff operations, wherein:

the base station is adapted to communicate with the remote terminal via a first subset of types of CDMA channels at a first sectorization level of a cell-site sectorization scheme; and

the base station is adapted to simultaneously communicate with the remote terminal via a second subset of types of CDMA channels, different from the first subset, at a second sectorization level of the cell-site sectorization scheme, having a degree of sectorization different from the degree of sectorization of the first sectorization level, wherein;

a cell corresponding to the base station is simultaneously sectorized at (1) the first sectorization level for communications between the base station and the individual remote terminal using the first subset of types of CDMA channels and (2) the second sectorization level for communications between the base station and the individual remote terminal using the second subset of types of CDMA channels;

the types of CDMA channels comprise one or more of pilot, sync, paging, and forward link traffic channels transmitted from the base station to the remote terminal, and one or more of access and reverse link traffic channels transmitted from the remote terminal to the base station;

the first subset comprises one or more of the pilot and sync channels; and

the second subset comprises one or more of the access, paging, forward link traffic, and reverse link traffic channels.

7. The base station of claim 6, wherein the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

8. The base station of claim 6, wherein the first sectorization level has a lower degree of sectorization than the second sectorization level.

9. The base station of claim 8, wherein:

at the first sectorization level, the cell site is omnidirectional;

at the second sectorization level, the cell site is sectorized into two or more sectors; and

one PN offset is assigned to the cell site; and

the cell site transmits signals corresponding to one pilot channel.

10. The base station of claim 8, wherein:

at the first sectorization level, the cell site is sectorized into two or more sectors;

at the second sectorization level, each sector is further sectorized into two or more sub-sectors;

one PN offset is assigned to each sector;

each sector transmits signals corresponding to one pilot channel; and

the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

11. A remote terminal for communicating with a base station of a CDMA-based communications network during non-handoff operations, wherein:

the remote terminal is adapted to communicate with the base station via a first subset of types of CDMA channels at a first sectorization level of a cell-site sectorization scheme; and

the remote terminal is adapted to simultaneously communicate with the base station via a second subset of types of CDMA channels, different from the first subset, at a second sectorization level of the cell-site sectorization scheme, having a degree of sectorization different from the degree of sectorization of the first sectorization level, wherein;

a cell corresponding to the base station is simultaneously sectorized at (1) the first sectorization level for communications between the base station and the remote terminal using the first subset of types of CDMA channels and (2) the second sectorization level for communications between the base station and the remote terminal using the second subset of types of CDMA channels;

the types of CDMA channels comprise one or more of pilot, sync, paging, and forward link traffic channels transmitted from the base station to the remote terminal, and one or more of access and reverse link traffic channels transmitted from the remote terminal to the base station;

the first subset comprises one or more of the pilot and sync channels; and

the second subset comprises one or more of the access, paging, forward link traffic, and reverse link traffic channels.

12. The remote terminal of claim 11, wherein the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

13. The remote terminal of claim 11, wherein the first sectorization level has a lower degree of sectorization than the second sectorization level.

14. The remote terminal of claim 13, wherein:

at the first sectorization level, the cell site is omnidirectional;

at the second sectorization level, the cell site is sectorized into two or more sectors; and

one PN offset is assigned to the cell site; and

the cell site transmits signals corresponding to one pilot channel.

15. The remote terminal of claim 13, wherein:

at the first sectorization level, the cell site is sectorized into two or more sectors;

at the second sectorization level, each sector is further sectorized into two or more sub-sectors;

one PN offset is assigned to each sector;

each sector transmits signals corresponding to one pilot channel; and

the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

16. A method for communicating between a base station and an individual remote terminal of a CDMA-based communications network, comprising the steps of:

(a) communicating between the base station and the individual remote terminal via a first subset of types of CDMA channels at a first sectorization level of a cell-site sectorization scheme; and

(b) simultaneously communicating between the base station and the individual remote terminal via a second subset of types of CDMA channels, different from the first subset, at a second sectorization level of the cell-site sectorization scheme, having a degree of sectorization different from the degree of sectorization of the first sectorization level, wherein;

a cell corresponding to the base station is simultaneously sectorized at (1) the first sectorization level for communications between the base station and the individual remote terminal using the first subset of types of CDMA channels and (2) the second sectorization level for communications between the base station and the individual remote terminal using the second subset of types of CDMA channels;

the types of CDMA channels comprise one or more of pilot, sync, paging, and forward link traffic channels transmitted from the base station to the remote terminal, and one or more of access and reverse link traffic channels transmitted from the remote terminal to the base station;

the first subset comprises one or more of the pilot and sync channels;

the second subset comprises one or more of the access, paging, forward link traffic, and reverse link traffic channels,

no traffic channels correspond to the first sectorization level; and

no pilot and sync channels correspond to the second sectorization level.

17. The method of claim 16, wherein the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

18. The method of claim 16, wherein the first sectorization level has a lower degree of sectorization than the second sectorization level.

19. The method of claim 18, wherein:

at the first sectorization level, the cell site is omnidirectional;

at the second sectorization level, the cell site is sectorized into two or more sectors; and

one PN offset is assigned to the cell site; and

the cell site transmits signals corresponding to one pilot channel.

20. The method of claim 18, wherein:

at the first sectorization level, the cell site is sectorized into two or more sectors;

at the second sectorization level, each sector is further sectorized into two or more sub-sectors;

one PN offset is assigned to each sector;

each sector transmits signals corresponding to one pilot channel; and

the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

21. A base station of a CDMA-based communications network for communicating with an individual remote terminal, wherein:

the base station is adapted to communicate with the remote terminal via a first subset of types of CDMA channels at a first sectorization level of a cell-site sectorization scheme; and

the base station is adapted to simultaneously communicate with the remote terminal via a second subset of types of CDMA channels, different from the first subset, at a second sectorization level of the cell-site sectorization scheme, having a degree of sectorization different from the degree of sectorization of the first sectorization level, wherein;

a cell corresponding to the base station is simultaneously sectorized at (1) the first sectorization level for communications between the base station and the individual remote terminal using the first subset of types of CDMA channels and (2) the second sectorization level for communications between the base station and the individual remote terminal using the second subset of types of CDMA channels;

the types of CDMA channels comprise one or more of pilot, sync, paging, and forward link traffic channels transmitted from the base station to the remote terminal, and one or more of access and reverse link traffic channels transmitted from the remote terminal to the base station;

the first subset comprises one or more of the pilot and sync channels;

the second subset comprises one or more of the access, paging, forward link traffic, and reverse link traffic channels;

no traffic channels correspond to the first sectorization level; and

no pilot and sync channels correspond to the second sectorization level.

22. The base station of claims 21, wherein the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

23. The base station of claim 21, wherein the first sectorization level has a lower degree of sectorization than the second sectorization level.

24. The base station of claim 23, wherein:

at the first sectorization level, the cell site is omnidirectional;

at the second sectorization level, the cell site is sectorized into two or more sectors; and

one PN offset is assigned to the cell site; and

the cell site transmits signals corresponding to one pilot channel.

25. The base station of claim 23, wherein:

at the first sectorization level, the cell site is sectorized into two or more sectors;

at the second sectorization level, each sector is further sectorized into two or more subsectors;

one PN offset is assigned to each sector;

each sector transmits signals corresponding to one pilot channel; and

the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

26. A remote terminal for communicating with a base station of a CDMA-based communications network, wherein:

the remote terminal is adapted to communicate with the base station via a first subset of types of CDMA channels at a first sectorization level of a cell-site sectorization scheme; and

the remote terminal is adapted to simultaneously communicate with the base station via a second subset of types of CDMA channels, different from the first subset, at a second sectorization level of the cell-site sectorization scheme, having a degree of sectorization different from the degree of sectorization of the first sectorization level, wherein;

a cell corresponding to the base station is simultaneously sectorized at (1) the first sectorization level for communications between the base station and the remote terminal using the first subset of types of CDMA channels and (2) the second sectorization level for communications between the base station and the remote terminal using the second subset of types of CDMA channels;

the types of CDMA channels comprise one or more of pilot, sync, paging, and forward link traffic channels transmitted from the base station to the remote terminal, and one or more of access and reverse link traffic channels transmitted from the remote terminal to the base station;

the first subset comprises one or more of the pilot and sync channels;

the second subset comprises one or more of the access, paging, forward link traffic, and reverse link traffic channels;

no traffic channels correspond to the first sectorization level; and

no pilot and sync channels correspond to the second sectorization level.

27. The remote terminal of claim 26, wherein the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.

28. The remote terminal of claim 26, wherein the first sectorization level has a lower degree of sectorization than the second sectorization level.

29. The remote terminal of claim 28, wherein:

at the first sectorization level, the cell site is omnidirectional;

at the second sectorization level, the cell site is sectorized into two or more sectors; and

one PN offset is assigned to the cell site; and

the cell site transmits signals corresponding to one pilot channel.

30. The remote terminal of claim 28, wherein:

at the first sectorization level, the cell site is sectorized into two or more sectors;

at the second sectorization level, each sector is further sectorized into two or more sub-sectors;

one PN offset is assigned to each sector;

each sector transmits signals corresponding to one pilot channel; and

the phasing of sectorization at the first sectorization level is selected to reduce the average expected number of pilot channels within the network.