Frequency plan for a cellular network

• US 5,483,667 A
• Filed: 07/08/1993
• Issued: 01/09/1996
• Est. Priority Date: 07/08/1993
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Faruque, Saleh M.
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): VO, NGUYEN THANH
• Application Number:
  US08/089,083
• Time in Patent Office: 915 Days
• Field of Search: 455/33.1, 455/33.2, 455/33.3, 455/33.4, 455/63, 455/56.1, 455/34.1, 455/34.2, 455/54.1, 455/49.1, 455/53.1, 455/103, 455/132, 455/272, 379/59, 379/58, 379/60
• US Class Current: 455/447
• 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

Abstract

An N=3 frequency plan for 60 degree sector transmit sector receive (STSR) cell sites is based upon dividing available channels into 18 frequency groups. Frequency assignment is in accordance with an odd-even cyclic distribution of channels which provides a three-channel separation between sectors within a cell and at least seven-channel separation between adjacent cells. This ensures adequate channel isolation between sectors and improved adjacent channel C/I performance throughout the network. The N=3 frequency plan increases channel capacity by approximately 38% in AMPS and 114% in TDMA-3.

Claims

1. In a sixty degree sector transmit sector receive cellular network with an N=3 frequency plan wherein available channel frequencies are divided into eighteen frequency groupings, a method of assigning frequencies comprising the steps of:

forming a generally triangular first three-cell cluster;

dividing each cell of the first three-cell cluster into six sectors; and

for said each cell, assigning, in an order, one frequency grouping to each sector to provide a separation of three channel frequencies between each sector within said each cell and a separation of at least seven channel frequencies between adjacent cells.

2. A method as claimed in claim 1 further comprising the step of allowing cell growth within the cellular network by forming a second generally triangular three-cell cluster, dividing each cell of the second three-cell cluster into six sectors, and assigning one frequency grouping to each sector of said each cell of the second three-cell cluster in the order of said first three-cell cluster.

3. A method as claimed in claim 2 wherein the frequency groupings are labeled 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A, 9A, 1B, 2B, 3B, 4B, 5B, 6B, 7B, 8B, 9B.

4. A method as claimed in claim 3 wherein the order of assigning one frequency grouping to each sector for a first cell in the second three-cell cluster is 1A, 4A, 7A, 1B, 4B, 7B.

5. A method as claimed in claim 4 wherein the order of assigning one frequency grouping to each sector for a second cell in the second three-cell cluster is 2A, 5A, 8A, 2B, 5B, 8B.

6. A method as claimed in claim 5 wherein the order of assigning one frequency grouping to each sector for a third cell in the second three-cell cluster is 3A, 6A, 9A, 3B, 6B, 9B.

7. A method as claimed in claim 6 wherein a sector of the first cell in the second three-cell cluster, assigned the frequency grouping 4A, abuts a sector of the second cell in the second three-cell cluster, assigned the frequency grouping 5B.

8. A method as claimed in claim 6 wherein a sector of the second cell in the second three-cell cluster, assigned the frequency grouping 2B, abuts a sector of the third cell in the second three-cell cluster, assigned the frequency grouping 3A.

9. A method as claimed in claim 6 wherein a sector of the third cell in the second three-cell cluster, assigned the frequency grouping 9B, abuts a sector of the first cell in the second three-cell cluster, assigned the frequency grouping 7A.

10. A method as claimed in claim 1 wherein the frequency groupings are labeled 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A, 9A, 1B, 2B, 3B, 4B, 5B, 6B, 7B, 8B, 9B.

11. A method as claimed in claim 10 wherein the order of assigning one frequency grouping to each sector for a first cell in the first three-cell cluster is 1A, 4A, 7A, 1B, 4B, 7B.

12. A method as claimed in claim 11 wherein the order of assigning one frequency grouping to each sector for a second cell in the first three-cell cluster is 2A, 5A, 8A, 2B, 5B, 8B.

13. A method as claimed in claim 12 wherein the order of assigning one frequency grouping to each sector for a third cell in the first three-cell cluster is 3A, 6A, 9A, 3B, 6B, 9B.

14. A method as claimed in claim 13 wherein a sector of the first cell in the first three-cell cluster, assigned the frequency grouping 4A, abuts a sector of the second cell in the first three-cell cluster, assigned the frequency grouping 5B.

15. A method as claimed in claim 13 wherein a sector of the second cell in the first three-cell cluster, assigned the frequency grouping 2B, abuts a sector of the third cell in the first three-cell cluster, assigned the frequency grouping 3A.

16. A method as claimed in claim 13 wherein a sector of the third cell in the first three-cell cluster, assigned the frequency grouping 9B, abuts a sector of the first cell in the first three-cell cluster, assigned the frequency grouping 7A.

17. A base station for sixty degree sector transmit sector receive cellular network with an N=3 frequency plan wherein available channel frequencies are divided into eighteen frequency groupings, the base station comprising:

a first plurality of transmitters for a first subset of the available channel frequencies;

a first combiner for combining output from the first plurality of transmitters;

a first duplexer for providing the combined output to a first transmitting/receiving antenna for transmission;

a second plurality of transmitters for a second subset of the available channel frequencies;

a second combiner for combining output from the second plurality of transmitters;

a second duplexer for providing the combined output from the second combiner to a second transmitting/receiving antenna for transmission;

a first receive multi-coupler connected to the first duplexer for receiving a signal from the first antenna;

a second receive multi-coupler connected to the second duplexer for receiving a signal from the second antenna;

a first receiver having a primary splitter connected between the first receive multi-coupler and a primary receiver and a secondary splitter connected between the second multi-coupler and a secondary receiver; and

a second receiver having a primary splitter connected to the second receive multi-coupler and a secondary splitter connected to the first receive multi-coupler.

18. A base station as claimed in claim 17 wherein the first subset of the available channel frequencies includes every odd channel of a frequency grouping and the second subset of the available channel frequencies includes every even channel of the frequency grouping wherein channel separation is doubled compared with transmitting with a single antenna.