Radio base station device and radio communication method

• US 20020160813A1
• Filed: 08/07/2001
• Published: 10/31/2002
• Est. Priority Date: 12/08/1999
• Status: Active Grant

• Current Assignee: Zavala Licensing LLC (IP Edge LLC)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Miya, Kazuyuki
• Granted Patent: US 6,684,086 B2
• Time in Patent Office: Days
• US Class Current: 455/562.1
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

Direction of arrival estimation sections 106a and 106b estimate directions of arrival for communication terminals. Grouping decision section 107 divides the communication terminals that belong to a sector into a plurality of groups based on the results of direction of arrival estimations. Scramble code assignment control section 114 performs assignment control in such a way that a same scramble code is assigned to channels with similar (not necessarily completely the same) directivities.

Claims

1. A radio base station apparatus comprising:

direction of arrival estimating means for estimating directions of arrival of reception signals from communication terminals;

dividing means for dividing said communication terminals into groups based on said directions of arrival;

scramble code assignment controlling means for assigning scramble codes differing from one said group to another; and

transmitting means for performing transmission with directivity of transmission signals modulated using the assigned scramble codes to said communication terminals.

2. The radio base station apparatus according to claim 1, wherein the dividing means divides said communication terminals into transmission groups based on said directions of arrival in transmission to the communication terminals.

3. The radio base station apparatus according to claim 2, wherein the dividing means carries out re-dividing processing based on code resource information.

4. The radio base station apparatus according to claim 1, wherein the transmitting means performs directivity control individually on the communication terminals.

5. The radio base station apparatus according to claim 1, wherein the transmitting means performs same directivity control on the communication terminals that belong to each group.

6. The radio base station apparatus according to claim 1, wherein the direction of arrival estimating means carries out reception with directivity to reception signals based on the directions of arrival estimated by the direction of arrival estimating means.

7. The radio base station apparatus according to claim 1, wherein the scramble code assignment controlling means changes scramble code assignment control based on code resource information.

8. The radio base station apparatus according to claim 7, wherein the scramble code assignment controlling means performs control by assigning scramble codes using groups classified by the dividing means when there is a shortage of spreading codes, and assigns a same scramble code to a plurality of groups when there is no shortage of spreading codes.

9. The radio base station apparatus according to claim 1, comprising:

notifying means for notifying, when a communication terminal changes the group as a result of movement, said communication terminal that the scramble code will be changed; and

changeover timing controlling means for controlling timing to change said scramble code, wherein said scramble code assignment controlling means assigns scramble codes after the changeover to said communication terminal whose group has been changed due to said movement.

10. The radio base station apparatus according to claim 1, wherein the scramble code assignment controlling means performs assignment control in such a way that a scramble code set in at least one of the channels carrying out transmission with directivity matches the scramble code set in the channel carrying out transmission with no directivity.

11. The radio base station apparatus according to claim 10, wherein the scramble code assignment controlling means assigns the same scramble code as the scramble code set in the channel carrying out transmission with no directivity to a group to which the most communication terminals belong.

12. The radio base station apparatus according to claim 1, wherein the scramble code assignment controlling means performs assignment control in such a way that the scramble code set in the channel carrying out transmission with directivity is different from the scramble code set in the channel carrying out transmission with no directivity.

13. The radio base station apparatus according to claim 12, comprising an antenna for channels with no directivity and another antenna for channels with directivity.

14. The radio base station apparatus according to claim 12, comprising the same antenna for channels with no directivity as the antenna for channels with directivity.

17. The radio communication method according to claim 16, comprising:

a notifying step of notifying, when a communication terminal changes the group as a result of movement, said communication terminal that the scramble code will be changed; and

a changeover timing controlling step of controlling timing to change said scramble code, wherein said scramble code assignment controlling step assigns scramble codes after the changeover to said communication terminal whose group needs to be changed due to said movement.

18. The radio communication method according to claim 16, wherein the scramble code assignment controlling step assigns the same scramble code as the scramble code set in the channel carrying out transmission with no directivity to a group to which the most communication terminals belong.

19. The radio communication method according to claim 16 that performs processing of assigning scrambling codes differing from one group to another only when there is a shortage of spreading codes.

15. A communication terminal apparatus that carries out radio communication with a radio base station apparatus, said radio base station apparatus comprising:

direction of arrival estimating means for estimating directions of arrival of reception signals from communication terminals;

dividing means for dividing said communication terminals into groups based on said directions of arrival;

scramble code assignment controlling means for assigning scramble codes differing from one said group to another; and

transmitting means for performing transmission with directivity of transmission signals modulated using the assigned scramble codes to said communication terminals.

16. A radio communication method comprising:

a direction of arrival estimating step of estimating directions of arrival of reception signals from communication terminals;

a dividing step of dividing said communication terminals into groups based on said directions of arrival;

a scramble code assignment controlling step of assigning scramble codes differing from one said group to another; and

a transmitting step of performing transmission with directivity of transmission signals modulated using the assigned scramble codes to said communication terminals.