Multicast message communicating method, multicast message communicating system, base station thereof, and mobile station thereof

• US 6,728,226 B1
• Filed: 06/20/2000
• Issued: 04/27/2004
• Est. Priority Date: 06/22/1999
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Naito, Kosuke
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Fox, Jamal A.
• Application Number:
  US09/598,011
• Time in Patent Office: 1,407 Days
• Field of Search: 370/331, 370/395.1, 370/328, 370/342, 370/312, 455/555, 455/24, 455/504, 455/505, 455/506, 455/522, 455/69, 455/503, 455/127.1, 455/101
• US Class Current: 370/328
• CPC Class Codes: H04W 52/327 Power control of multicast channels

Abstract

A multicast message communicating system is disclosed, that comprises a base station for transmitting a multicast message using a multicast channel, and a plurality of mobile stations for receiving the multicast message from the base station, wherein the base station has a receiving portion for receiving transmission power increase request signals from the plurality of mobile stations corresponding to reception powers of the multicast message received from the plurality of mobile stations, a reception power detecting portion for detecting the reception powers of the transmission power increase request signals received from the receiving portion, a transmission power control generating means for deciding and generating a transmission power increase request signal or a transmission power decrease request signal for the plurality of mobile stations corresponding to the received powers.

Claims

1. A multicast message communicating system, comprising:

a base station for transmitting a multicast message using a multicast channel; and

a plurality of mobile stations for receiving the multicast message from said base station,

wherein said base station has;

a receiving portion for receiving transmission power increase request signals from said plurality of mobile stations corresponding to reception powers of the multicast message received by said plurality of mobile stations;

a reception power detecting portion for detecting the reception powers of the transmission power increase request signals received from the receiving portion;

transmission power control generating means for deciding and generating a transmission power increase request signal or a transmission power decrease request signal for said plurality of mobile stations corresponding to the received powers; and

a power controlling portion for controlling the transmission power of the multicast message transmitted to said plurality of mobile stations corresponding to the reception powers,

wherein the multicast message and the transmission power increase request signal or the transmission power decrease request signal are transmitted to said plurality of mobile stations, and

wherein said plurality of mobile stations gradually decrease the transmission powers of the transmission power increase request signals corresponding to the reception powers of the transmission power increase request signal or the transmission power decrease request signal, and the multicast message received from said base station.

2. The multicast message communicating system as set forth in claim 1,

wherein each of said plurality of mobile stations has:

demodulating means for receiving the multicast message and demodulating it;

reception power detecting means for detecting the reception power of the multicast message received by the demodulating means;

transmission power increase/decrease request signal detecting means for detecting the transmission power increase request signal or the transmission power decrease request signal received from said base station; and

transmission power controlling means for deciding the transmission power of the transmission power increase request signal to be transmitted to said base station,

wherein when the demodulating means receives the multicast message with sufficient quality from said base station, the transmission power controlling means gradually decreases the transmission power of the transmission power increase request signal.

3. The multicast message communicating system as set forth in claim 1,

wherein the power controlling portion of said base station increases the transmission power of the multicast message in condition (1) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations exceeds a second threshold value,

wherein the power controlling portion of said base station decreases the transmission power of the multicast message in condition (2) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations is equal to or smaller than the second threshold value for a predetermined time period, and

wherein the power controlling portion of said base station does not vary the transmission power of the multicast message in condition (3) of which the conditions (1) and (2) are not satisfied.

4. The multicast message communicating system as set forth in claim 1,

wherein when the reception power of the multicast message received from each of said plurality of mobile stations is equal to or larger than a fourth threshold value, the transmission power of the transmission power increase request signal transmitted to said base station is gradually decreased.

5. The multicast message communicating system as set forth in claim 1,

wherein said base station controls the transmission power of the multicast message corresponding to the reception power of the transmission power increase request signal received from each of said plurality of mobile stations.

6. The multicast message communicating system as set forth in claim 2,

wherein the power controlling portion of said base station increases the transmission power of the multicast message in condition (1) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations exceeds a second threshold value,

wherein the power controlling portion of said base station decreases the transmission power of the multicast message in condition (2) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations is equal to or smaller than the second threshold value for a predetermined time period, and

wherein the power controlling portion of said base station does not vary the transmission power of the multicast message in condition (3) of which the conditions (1) and (2) are not satisfied.

7. The multicast message communicating system as set forth in claim 2,

wherein when the reception power of the multicast message received from each of said plurality of mobile stations is equal to or larger than a fourth threshold value, the transmission power of the transmission power increase request signal transmitted to said base station is gradually decreased.

8. The multicast message communicating system as set forth in claim 2,

wherein said base station controls the transmission power of the multicast message corresponding to the reception power of the transmission power increase request signal received from each of said plurality of mobile stations.

9. The multicast message communicating system as set forth in claim 3,

wherein when the reception power of the multicast message received from each of said plurality of mobile stations is equal to or larger than a fourth threshold value, the transmission power of the transmission power increase request signal transmitted to said base station is gradually decreased.

10. The multicast message communicating system as set forth in claim 3,

wherein said base station controls the transmission power of the multicast message corresponding to the reception power of the transmission power increase request signal received from each of said plurality of mobile stations.

11. A multicast message communicating method having a base station for transmitting a multicast message using a multicast channel and a plurality of mobile stations for receiving the multicast message from the base station, the method comprising the steps of:

(a) receiving transmission power increase request signals from the plurality of mobile stations corresponding to reception powers of the multicast message received by the plurality of mobile stations;

(b) detecting the reception powers of the transmission power increase request signals received from the receiving portion;

(c) deciding and generating a transmission power increase request signal or a transmission power decrease request signal for the plurality of mobile stations corresponding to the received powers; and

(d) controlling the transmission power of the multicast message transmitted to the plurality of mobile stations corresponding to the reception powers,

wherein the steps (a) to (d) are performed by the base station,

wherein the multicast message and the transmission power increase request signal or the transmission power decrease request signal are transmitted to the plurality of mobile stations, and

wherein the plurality of mobile stations gradually decrease the transmission powers of the transmission power increase request signals corresponding to the reception powers of the transmission power increase request signal or the transmission power decrease request signal, and the multicast message received from the base station.

12. The multicast message communicating method as set forth in claim 11,

(e) receiving the multicast message and demodulating it;

(f) detecting the reception power of the multicast message received by the demodulating means;

(g) detecting the transmission power increase request signal or the transmission power decrease request signal received from the base station; and

(h) deciding the transmission power of the transmission power increase request signal to be transmitted to the base station,

wherein the steps (e) to (h) are performed by each of the plurality of mobile stations.

13. The multicast message communicating method as set forth in claim 11,

wherein when the reception power of the multicast message received from each of the plurality of mobile stations is equal to or larger than a fourth threshold value, the transmission power of the transmission power increase request signal transmitted to the base station is gradually decreased.

14. The multicast message communicating method as set forth in claim 12,

wherein when the reception power of the multicast message received from each of the plurality of mobile stations is equal to or larger than a fourth threshold value, the transmission power of the transmission power increase request signal transmitted to the base station is gradually decreased.

15. A base station for transmitting a multicast message to a plurality of mobile stations using a multicast channel, comprising:

a receiving portion for receiving transmission power increase request signals from the plurality of mobile stations corresponding to reception powers of the multicast message received by the plurality of mobile stations;

a reception power detecting portion for detecting the reception powers of the transmission power increase request signals received from said receiving portion;

transmission power control generating means for deciding and generating a transmission power increase request signal or a transmission power decrease request signal for the plurality of mobile stations corresponding to the received powers; and

a power controlling portion for controlling the transmission power of the multicast message transmitted to the plurality of mobile stations corresponding to the reception powers,

wherein the multicast message and the transmission power increase request signal or the transmission power decrease request signal cause the transmission powers of the plurality of mobile stations to be increased or decreased, and

wherein the plurality of mobile stations gradually decrease the transmission powers of the transmission power increase request signals corresponding to the reception powers of the transmission power increase request signal or the transmission power decrease request signal, and the multicast message received from the base station.

16. The base station for transmitting a multicast message to a plurality of mobile stations using the multicast channel as set forth in claim 15,

wherein when the mobile station receives the multicast message with sufficient quality from said base station, a transmission power controlling means of the mobile station gradually decreases the transmission power of the transmission power increase request signal from the mobile station.

17. The base station for transmitting a multicast message to a plurality of mobile stations using the multicast channel as set forth in claim 15,

wherein the power controlling portion of the base station increases the transmission power of the multicast message in condition (1) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations exceeds a second threshold value,

wherein the power controlling portion of said base station decreases the transmission power of the multicast message in condition (2) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations is equal to or smaller than the second threshold value for a predetermined time period, and

wherein the power controlling portion of said base station does not vary the transmission power of the multicast message in condition (3) of which the conditions (1) and (2) are not satisfied.

18. A mobile station for receiving a multicast message from a base station using a multicast channel, comprising:

a receiving portion for receiving the multicast message and a transmission power increase request signal or a transmission power decrease request from the base station;

a reception power detecting portion for detecting the reception power of the multicast message received from said receiving portion; and

a power controlling portion for comparing the reception power with a predetermined threshold value, stopping transmitting the transmission power increase request signal to the base station when the reception power is larger than the predetermined threshold value, and increasing the transmission power of the transmission power increase request signal when the reception power is equal to or smaller than the predetermined threshold value and said receiving portion receives the transmission power decrease request signal, wherein when said power controlling portion stops transmitting the transmission power increase request signal to the base station, said power controlling portion gradually decreases the transmission power thereof.

19. The mobile station for receiving the multicast message from the base station using a multicast channel, as set forth in claim 18,

wherein when the mobile station receives the multicast message with sufficient quality from said base station, a transmission power controlling means of the mobile station gradually decreases the transmission power of the transmission power increase request signal from the mobile station.

20. The mobile station for receiving the multicast message from a base station using the multicast channel, as set forth in claim 18,

wherein the power controlling portion of the base station increases a transmission power of the multicast message in condition (1) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations exceeds a second threshold value,

wherein the power controlling portion of said base station decreases the transmission power of the multicast message in condition (2) of which the reception power of the transmission power increase request signal received from each of said plurality of mobile stations is equal to or smaller than the second threshold value for a predetermined time period, and

wherein the power controlling portion of said base station does not vary the transmission power of the multicast message in condition (3) of which the conditions (1) and (2) are not satisfied.