Time slot assigning method, signal transmission method, base station control apparatus, base station, and mobile station used in a mobile communications system

• US 20030017830A1
• Filed: 07/16/2002
• Published: 01/23/2003
• Est. Priority Date: 07/17/2001
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Kayama, Hidetoshi, Chen, Lan, Umeda, Narumi
• Granted Patent: US 7,580,387 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

A time slot assigning method for assigning a time slot for transmission of a signal between a base station and a mobile station in each frame is provided. The method comprises assigning a first slot group used for transmission of a down signal from the base station to the mobile station; assigning a second slot group used for transmission of an up signal from the mobile station to the base station are assigned; and arranging a third slot group immediately after the first slot group, the third slot group being used giving a priority to transmission of another down signal from the base station to the mobile station.

Claims

1. A time slot assigning method for assigning a time slot used for transmission of a signal between a base-station and a mobile station in each frame, the method comprising;

assigning a first slot group used for transmission of a down signal from the base station to the mobile station, the first slot group consisting of one or more successive time slots;

assigning a second slot group used for transmission of an up signal from the mobile station to the base station, the second slot group consisting of one or more successive time slots; and

arranging a third slot group immediately after the first slot group, the third slot group being used giving a priority to transmission of another down signal.

2. The method according to claim 1, further comprising:

defining an interference monitoring slot in the third slot group if there is no other down signal to be transmitted in the timing of the third slot group, the interference monitoring slot being used to monitor interference from other base stations.

3. The method according to claim 1, further comprising:

providing a switching slot in the third slot group, wherein a time slot after the switching slot in the third slot group is used to transmit another up signal from the mobile station to the base station.

4. The method according to claim 2, further comprising:

providing a switching slot in the third slot group if an interference level monitored in the interference monitoring slot satisfies a predetermined condition.

5. The method according to claim 4, wherein a time slot after the switching slot in the third slot group is used to transmit another up signal from the mobile station to the base station.

6. The method according to claim 1, further comprising:

determining a ratio of time slots between the first slot group, the second slot group, and the third slot group based on uplink traffic and downlink traffic between the base station and the mobile station.

7. A signal transmission method for transmitting signals between a base station and a mobile station in a mobile communication system, the method comprising:

determining a first slot group, a second slot group, and a third slot group in each radio frame, the third slot group being used for multiple purposes;

transmitting a down signal from the base station to the mobile station using the first slot group;

transmitting another down signal using at least a portion of the third slot group if there is said other down signal to be transmitted after the first slot group has been used; and

transmitting an up signal from the mobile station to the base station using the second slot group.

8. The signal transmission method according to claim 7, further comprising:

monitoring interference from other base stations using a portion of the third slot group;

determining whether the interference satisfies a predetermined condition; and

generating a switching signal if the interference satisfies the predetermined condition in order to allow the mobile station to transmit another up signal using the third slot group.

9. The signal transmission method according to claim 8, further comprising:

determining an order of priority for the up signal and said other up signal, wherein if said other up signal has a lower priority, said other up signal is transmitted using the third slot group after the switching signal is generated.

10. A base station control apparatus provided between a base station and a mobile station in a mobile communications system, the base station control apparatus comprising:

a traffic data collecting unit configured to collect traffic data from the base station; and

a slot group determination unit configured to assign a first slot group used for transmission of a down signal from the base station to the mobile station, a second slot group used for transmission of an up signal from the mobile station to the base station, and a third slot group used giving a priority to transmission of another down signal from the base station to the mobile station for each frame, based on the traffic data collected at the traffic data collecting unit.

11. The base station control apparatus according to claim 10, wherein the slot group determination unit determines a ratio between the first slot group, the second slot group, and the third slot group for each frame based on the traffic data collected at the traffic data collecting unit.

12. The base station control apparatus according to claim 11, wherein the traffic data collecting unit calculates a ratio of unlink traffic to downlink traffic from the traffic data collected from the base station, and the slot group determination unit determines the ratio between the first slot group, the second slot group, and the third slot group based on the ratio of uplink traffic to downlink traffic.

13. The base station control apparatus according to claim 10, wherein the base station control apparatus allows the base station to use the third slot group to monitor interference with other base station if there is no other down signal to be transmitted from the base station in the third slot group.

15. The base station according to claim 14 further comprising:

an interference monitoring unit configured to monitor interference from other base stations and supply a monitoring result to the controller, wherein the controller determines whether the monitoring result satisfies a predetermined condition, and if the predetermined condition is satisfied, the controller causes the base station to receive another up signal from the mobile station using a remaining portion of the third slot group.

16. The base station according to claim 15, wherein the controller causes the base station to transmit a switching control signal to the mobile station if the monitoring result satisfies the predetermined condition.

18. The mobile station according to claim 17, wherein the controller determines whether a switching control signal has been received in the third slot group, and if so, the controller causes the radio frequency processing unit to transmit said other up signal to the base station using the remaining portion of the third slot group.

19. The mobile station according to claim 17, further comprising:

a signal processing unit configured to set an order of priority for the up signal and said other up signal, wherein the controller causes the radio frequency processing unit to transmit said other up signal using the remaining portion of the third slot if said other up signal has a lower priority.

14. A base station in a mobile communications system, comprising:

an interface configured to receive assignment of time slots for each frame from an external control apparatus, said frame including a first slot group, a second slot group, and a third slot group;

a controller connected to the interface and configured to cause the base station to transmit a down signal to a mobile station using the first slot group, to cause the base station to use a portion of the third slot group to transmit another down signal if there is said other down signal to be transmitted after the first slot group has been used, and to cause the base station to receive an up signal from the mobile station using the second slot group.

17. A mobile station comprising:

a radio frequency processing unit configured to receive a down signal transmitted from a base station using a first slot group in a frame and to transmit an up signal to the base station using a second slot group in the frame; and

a controller configured to cause the radio frequency processing unit to receive another down signal from the base station using a portion of a third slot group in the frame and/or to transmit another up signal to the base station using a remaining portion of the third slot group.