RADIO COMMUNICATION SYSTEM, BASE STATION APPARATUS, AND RADIO COMMUNICATION METHOD

• US 20120243513A1
• Filed: 02/03/2012
• Published: 09/27/2012
• Est. Priority Date: 03/24/2011
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Fujishima, Kenzaburo, Tamaki, Tsuyoshi, Jia, Yunjian, Ishida, Hitoshi
• Granted Patent: US 8,891,417 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

To secure a constant level or more of radio communication quality for each user equipment performing radio communication with a base station apparatus, and to increase the number of user equipment which the base station apparatus can accommodate under a condition of assuring the radio communication quality. In a radio communication system where there exist a base station apparatus having multiple antennas and user equipment for performing radio communication with a first antenna group including one or more of the antennas, the first antenna group is made configurable for each user equipment individually, and addition/deletion of the antenna to/from the first antenna group is performed based on the communication quality of each user equipment so that the number of antennas within the first antenna group may be minimized within a range satisfying a required value of the communication quality between the base station apparatus ad the user equipment.

Claims

1. A radio communication system capable of communicating with user equipment, comprising:

a base station apparatus having a plurality of antennas and a controller which selects one or more antennas which should make up an antenna group based a quality of communication performed between the base station apparatus and the user equipment through one or more antennas among the antennas, and the number of antennas within the antenna group, and communicates with the user equipment through the first antenna group comprised of the selected antennas.

2. The radio communication system according to claim 1,

wherein the first antenna group is made up for the each user equipment,

wherein the antenna is added or deleted to/from the first antenna group being set up for the user equipment so that the communication quality between the base station apparatus and the user equipment satisfies a lower limit of the required value of the communication quality and the number of antennas within the first antenna group may be minimized, or the communication quality may fall within a range defined by the lower limit of the required value and an upper limit of the required value of the communication quality, and

wherein the base station apparatus communicates with the user equipment using at least the antennas of the first antenna group.

3. The radio communication system according to claim 2,

wherein all of or a part of the antennas among the antennas which the base station apparatus has and which excludes the antennas within the first antenna group are designated as of the second antenna group,

wherein the antennas within the first antenna group are specified to be the antennas which are sure to be used when the base station apparatus communicates with the user equipment, and

wherein the antennas within the second antenna group are used together with the antennas of the first antenna group when the base station apparatus communicates with any one of the user equipment.

4. The radio communication system according to claim 2,

wherein a processing of the addition or the deletion of the antenna to/from the first antenna group is performed by dividing it into multiple operations and by setting an interval between these operations.

5. The radio communication system according to claim 2,

wherein the lower limit of the required value of the communication quality and the upper limit of the required value of the communication quality which is larger than the lower limit of the required value of the communication quality are decided in advance as required communication qualities,

wherein the base station apparatus performs a processing of addition of the antenna to the first antenna group on condition which the communication quality gets lower than the lower limit of the required value of the communication quality, and

wherein the base station apparatus performs a processing of the deletion of the antenna from the first antenna group on condition which the communication quality exceeds the upper limit of the required value of the communication quality,

6. The radio communication system according to claim 5,

wherein the base station apparatus transmits the lower limit of the required value of the communication quality and the upper limit of the required value of the communication quality to the user equipment,

wherein the user equipment measures the communication quality with the base station apparatus, compares the measured communication quality with the lower limit of the required value of the communication quality and the upper limit of the required value of the communication quality, and performs determination of the addition or deletion of the antenna, and

wherein the base station apparatus performs a processing of adding the antenna or a processing of deleting the antenna based on the determination result.

7. The radio communication system according to claim 2,

wherein the base station apparatus measures the communication quality with each user equipment,

renews the first antenna group for each of the user equipment based on the measured communication quality, and

allocates radio communication resources for performing radio communication with the user equipment including the antennas in each time slot based on the renewed first antenna group.

8. The radio communication system according to claim 2,

wherein the number of spatial layers is decided in advance by negotiation of the base station apparatus and the user equipment, and

wherein, when the number of spatial layers that can be provided to the user equipment is changed by renewing the first antenna group, the negotiation of a transmission/reception scheme is performed again between the base station apparatus and the user equipment.

9. The radio communication system according to claim 8,

wherein a message which is exchanged between the base station apparatus and the user equipment when performing the negotiation again includes the number of spatial layers and an indicator for indicating which is a transmission scheme utilizing the spatial layers, the space division multiplexing transmission or the diversity transmission.

10. The radio communication system according to claim 3,

wherein the antennas within the first antenna group being set up for the user equipment are allocated to the user equipment, and

wherein an antenna of the second antenna group which is allocated to none of the user equipment is allocated to any one of the user equipment to which the antennas of the first antenna group are allocated so that the number of spatial layers decided in advance between the base station apparatus and the terminal may not be changed.

11. The radio communication system according to claim 10,

wherein the user equipment to which the antennas of the first antenna group are allocated in a predetermined frequency resource of a predetermined time slot based on an estimated result of an instantaneous data rate for each of the user equipment is selected sequentially, and

wherein, if all the antennas within the first antenna group of the selected user equipment are not allocated to any other user equipment in the frequency resource of the time slot, the antennas will be allocated to the user equipment which is selected.

12. The radio communication system according to claim 10,

wherein the same data signal as the data signal from any one of the antennas allocated from the first antenna group is transmitted from an antenna allocated from the second antenna group to the user equipment, and

wherein a data signal which was transmitted from the user equipment and is received by one of the both antennas and a data signal which was transmitted therefrom and is received by the other of the both antennas are added together.

13. The radio communication system according to claim 10,

wherein an antenna is added quality on priority basis from the second antenna group to the user equipment whose communication quality between the base station apparatus and the user equipment is close to or lower than the lower limit of the required value of the communication.

14. The radio communication system according to claim 2,

wherein the base station apparatus receives a pilot signal, a control signal, and a data signal from the user equipment, and estimates the communication quality, or the user equipment receives the pilot signal, the control signal, and the data signal from the base station apparatus, estimates the communication quality, and transmits the estimated result to the base station apparatus.

15. A radio communication method using a base station apparatus which has a plurality of antennas and performs radio communication with user equipment through a first antenna group being comprised of one or more antennas of the antennas,

wherein the first antenna group is made up for each user equipment,

wherein the antenna is added or deleted to/from the first antenna group being set up for the user equipment so that communication quality between a base station apparatus and the user equipment may satisfy a lower limit of the required value of the communication quality, and the number of antennas within the first antenna group may be minimized, or the communication quantity may fall within a range defined by the lower limit of the required value and an upper limit of the required value of the communication quality, and

wherein the base station apparatus communicates with the user equipment using at least the antennas of the first antenna group.