Wireless communication system and its control method

Abstract

To reduce a processing time of beam management in an environment where communications are performed with a plurality of base station antennas.SOLUTION: In a radio communication system, user equipment (UE) is configured connectable with a base station (BS) via a plurality of base station antennas (APs). Each of the plurality of APs transmits a downlink reference signal (DL_RS) periodically. In a case where it is determined that a signal quality of a received DL_RS is lower than a predetermined quality, the UE transmits a beam management (BM) implementation instruction with the UE to a first AP that transmits the DL_RS. Each of the plurality of APs other than the first AP transmits a non-periodic DL_RS based on transmitting the BM implementation instruction from the UE to the first AP. In a case where it is determined that a signal quality of the received non-periodic DL_RS is lower than the predetermined quality, the UE transmits the BM implementation instruction with the UE to a second AP that transmits the non-periodic DL_RS.SELECTED DRAWING: Figure 6

Claims

1. A wireless communication system configured such that user equipment (UE) can connect to a base station (BS) via multiple base station antennas (AP), Each of the aforementioned APs is configured to periodically transmit a downlink reference signal (DL_RS), The UE is configured to send a beam management (BM) instruction to the first AP that transmitted the DL_RS when it determines that the signal quality of the received DL_RS is lower than a predetermined quality. Each of the plurality of APs other than the first AP is configured to send an irregular DL_RS based on the fact that the BM implementation instruction has been sent from the UE to the first AP. The UE is configured to send a BM implementation instruction to the second AP that transmitted the non-periodic DL_RS when it determines that the signal quality of the received non-periodic DL_RS is lower than the predetermined quality. A wireless communication system characterized by the following features.

2. The UE is configured not to send a BM implementation instruction to the third AP that transmitted the non-periodic DL_RS if it determines that the signal quality of the received non-periodic DL_RS is equal to or better than the predetermined quality. The wireless communication system according to claim 1.

3. Information regarding the resources used for sending the aforementioned non-periodic DL_RS is shared between the UE and each AP. The wireless communication system according to claim 1.

4. Each of the multiple APs other than the first AP transmits the non-periodic DL_RS while beam sweeping. The wireless communication system according to claim 1.

5. The first AP is configured to notify the other APs that the BM implementation instruction has been sent from the UE to the first AP. Each of the multiple APs other than the first AP transmits the irregular DL_RS based on the notification from the first AP. The wireless communication system according to claim 1.

6. Information regarding the physical uplink control channel (PUCCH) resources used to transmit the aforementioned BM implementation instructions is shared between the UE and each AP. Each of the aforementioned APs is configured to monitor the PUCCH resource. The wireless communication system according to claim 1.

7. Each of the multiple APs other than the first AP transmits the non-periodic DL_RS based on the detection of the transmission of the BM implementation instruction by monitoring the PUCCH resource. The wireless communication system described in item 6.

8. Each of the aforementioned APs is configured as a multi-input multi-output (MIMO) antenna. The wireless communication system according to claim 1.

9. The aforementioned multiple APs are configured to be controlled by a centralized station that operates as the CU (Central Unit) of the BS. The wireless communication system according to claim 1.

10. A control method for a wireless communication system configured such that a user device (UE) can connect to a base station (BS) via multiple base station antennas (APs), Each of the aforementioned APs periodically transmits a downlink reference signal (DL_RS) in a first transmission step, The UE performs a first receiving step in which it receives DL_RS transmitted from the plurality of APs, A second transmission step in which the UE transmits a beam management (BM) instruction to a first AP that has transmitted a DL_RS whose signal quality has been determined to be lower than a predetermined quality, A third transmission step in which, based on the transmission of the BM implementation instruction from the UE to the first AP, each of the one or more APs other than the first AP included in the plurality of APs transmits an irregular DL_RS, A second transmission step in which the UE transmits a BM implementation instruction to a second AP that has transmitted an irregular DL_RS whose signal quality is determined to be lower than the predetermined quality, including A control method characterized by the following:

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