FREQUENCY ALLOCATION METHOD IN WIRELESS BASE STATION APPARATUS AND WIRELESS BASE STATION APPARATUS

• US 20100027489A1
• Filed: 05/28/2009
• Published: 02/04/2010
• Est. Priority Date: 08/04/2008
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: MAKINO, Satoshi, WATANABE, Kiezo, MATSUZAWA, Hiromu
• Granted Patent: US 8,374,620 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/30 Special cell shapes, e.g. doughnuts or ring cells
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA

Abstract

A frequency allocation method in a base station communicating wirelessly with a terminal, for dividing a cell into six areas in a clockwise direction, and allocating a frequency to each of the divided sectors, including: dividing the cell into an outer circle and an inner circle; allocating to a first terminal positioned in the outer circle of the sector, a frequency different from a frequency allocated to a second terminal positioned in an adjacent sector of the same cell, and the frequency different from a frequency allocated to a third terminal positioned in the outer circle of an adjacent sector of the adjacent cell; and allocating the frequency allocated to the first terminal to fourth and fifth terminal positioned in the inner circle of two sectors respectively arranged two sectors away from the sector in which the first terminal is positioned.

Claims

1. A frequency allocation method, in a wireless base station apparatus communicating wirelessly with a terminal apparatus, for dividing a cell that is a communication range of the wireless base station apparatus into six areas in a clockwise direction, and allocating a frequency to each of the divided sectors, the method comprising:

dividing the cell into an outer circle and an inner circle, wherein the outer circle is a range of the cell, and the inner circle is a range at a shorter distance from the wireless base station apparatus than the outer circle;

allocating to a first terminal apparatus positioned in the outer circle of the sector, a frequency different from a frequency allocated to a second terminal apparatus positioned in an adjacent sector of the same cell, and the frequency different from a frequency allocated to a third terminal apparatus positioned in the outer circle of an adjacent sector of the adjacent cell; and

allocating the frequency allocated to the first terminal apparatus to fourth and fifth terminal apparatus positioned in the inner circle of two sectors respectively arranged two sectors away from the sector in which the first terminal apparatus is positioned.

2. The frequency allocation method according to claim 1, further comprising reducing a transmission power to the fourth and fifth terminal apparatus positioned in the inner circle by 5.6 dB from the transmission power to the first terminal apparatus positioned in the outer circle, and transmitting data to the first, or to the fourth and fifth terminal apparatus.

3. The frequency allocation method according to claim 2, wherein the inner circle is divided such that the ratio of the distance from the wireless base station apparatus to the inner circle, to the distance from a wireless base station apparatus of the adjacent cell to the inner circle, is 1.9, when the cell is divided into the outer circle and the inner circle.

4. The frequency allocation method according to claim 1, wherein the frequency allocated to the first terminal apparatus is allocated to the fourth and fifth terminal apparatus with precedence when the frequency is allocated to the fourth and fifth terminal apparatus, and a frequency to be allocated to a sixth terminal apparatus positioned in the outer circle of the same sector as the inner circle in which the fourth or fifth terminal apparatus is positioned is allocated to the fourth or fifth terminal apparatus when the number of the fourth or fifth terminal apparatuses exceeds a first threshold and the frequency to be allocated to the fourth and fifth terminal apparatus can not be allocated.

5. A frequency allocation method in a wireless base station apparatus for dividing a cell that is a communication range of the wireless base station apparatus communicating wirelessly with a terminal apparatus into six areas in a clockwise direction, and allocating a frequency to each of the six divided sectors, the method comprising:

receiving measurement result of communication quality with the wireless base station apparatus from the terminal apparatus, and determining position information indicating whether the terminal apparatus is positioned in an outer circle which is a range of the cell, or in an inner circle which is a range at a shorter distance from the wireless base station apparatus than the outer circle on the basis of the measurement result in a first table;

selecting the frequency to be allocated to the terminal apparatus on the basis of the position information in a second table;

selecting a transmission power value for the terminal apparatus on the basis of the position information in a third table; and

transmitting and receiving data with the terminal apparatus at the selected frequency and transmission power value.

6. The frequency allocation method according to claim 5, wherein the wireless base station apparatus reduces the power of transmission to the terminal apparatuses positioned in the inner circle by 5.6 dB from the power of transmission to the terminal apparatuses positioned in the outer circle, and transmits the data, when the wireless base station transmits data to the terminal apparatuses at the selected frequency and transmission power value.

7. The frequency allocation method according to claim 6, wherein the inner circles are positioned in each of cells such that the ratio of the distance from the wireless base station apparatus to the inner circle, and the distance from a wireless base station apparatus of the adjacent cell to the inner circle, is 1.9.

8. The frequency allocation method according to claim 6, wherein the frequency to be allocated to the terminal apparatus is allocated to the terminal apparatus positioned in the inner circle with precedence when the frequency allocated to the terminal apparatus is selected, and a frequency to be allocated to the outer circle in the same sector as the inner circle is selected when the number of the terminal apparatuses positioned in the inner circle exceeds a second threshold value and the frequency to be allocated to the terminal apparatus can not be allocated.

9. The frequency allocation method according to claim 6, wherein

the first table stores a third threshold value for the measurement results, and

it is judged that the terminal is positioned in the outer circle if the measurement result is smaller than the third threshold value, and it is judged that the terminal is positioned in the inner circle if the measurement result is equal to or larger than the third threshold value, when the position information is determined.

10. The frequency allocation method according to claim 6, wherein

the second table stores sector number for identifying each of the sectors in the cell, the position information, and the frequency, and

the sector number is acquired based on the received measurement result, and the frequency is selected on the basis of the acquired sector number and the position information in the second table, when the frequency to be allocated to the terminal apparatus is selected.

11. A wireless base station apparatus for dividing a cell that is a range of wireless communication of the wireless base station apparatus with a terminal apparatus into six areas in a clockwise direction and allocating a frequency to each of the divided sectors, comprising:

a storage unit which stores a first table including a measurement result for communication quality with the terminal apparatuses and a position information indicating whether the terminal apparatus is positioned in an outer circle which is a range of the cell or in an inner circle at a shorter distance from the wireless base station apparatus than the outer circle, a second table including the position information and the frequency to be allocated to the terminal apparatus, and a third table including the position information and a transmission power value for the terminal apparatus; and

a control unit which receives the measurement results from the terminal apparatuses, acquires the position information on the basis of the measurement result in the first table, selects the frequency to be allocated on the basis of the acquired position information in the second table, selects the transmission power value for the terminal apparatus on the basis of the acquired position information in the third table, and communicates wirelessly with the terminal apparatus at the selected frequency and the selected transmission power value.