Channel accessing method and device in wireless communication system

• US 10,638,331 B2
• Filed: 09/15/2015
• Issued: 04/28/2020
• Est. Priority Date: 09/15/2014
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ryoo, Sunheui, Jung, Jungsoo, Moon, Jungmin, Nigam, Anshuman, Lee, Sungjin
• Primary Examiner(s): Renner, Brandon M
• Application Number:
  US15/511,209
• Publication Number:
  US 20170257780A1
• Time in Patent Office: 1,687 Days
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/088 using beam selection
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/0069 in case of dual connectivity, e.g. decoupled uplink/downlink
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/28 involving a plurality of connections, e.g. multi-call or multi-bearer connections
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

The present invention relates to a channel accessing method and device in a wireless communication system and, particularly, to a channel accessing method and device for a call handover for a terminal in a wireless communication system using a plurality of beams. The method according to an embodiment of the present invention, as a method of controlling a macro cell base station when a terminal that is communicating with the macro cell base station performs channel access with a small cell base station in a wireless network capable of using a plurality of transmitting/receiving beams, may include the steps of: determining whether to request a channel setting for a call for the terminal to the small cell base station when a signal strength measurement report for a channel synchronized with the small cell base station is received from the terminal; providing information including at least one of recommending information on the transmitting/receiving beams of the terminal and position information on the terminal in a request message to the small cell base station when a channel setting request to the small cell base station is decided upon; stopping the transmission of data to the terminal and a set data radio bearer (DRB2) when a response message for accepting the channel setting for the terminal is received from the small cell base station; transmitting a radio resource control access reconfiguration message to the terminal to communicate with the small cell base station; and providing information on data to be transmitted and received by the terminal to the small cell base station.

Claims

1. A channel access method for a small cell eNodeB (eNB) to set up a channel with a user equipment (UE) which is in a process of communication with a macro-cell eNB in a wireless network capable of using a number of transmission/reception beams, the method comprising:

receiving a request message for requesting setup of a channel with the UE from the macro-cell eNB, setting up a data radio bearer (DRB2) to communicate with the UE, and transmitting a response (acknowledgement) message to the macro-cell eNB;

receiving, from the macro-cell eNB, information related to data to be transmitted to the UE;

reordering an order of beams to receive a preamble via a RACH from the UE, based on information included in the request message, and scanning the RACH; and

receiving a preamble signal of the UE via the RACH, creating a RACH response signal, transmitting the RACH response signal to the UE, and performing a procedure for setting up a channel.

2. The method of claim 1, wherein receiving a preamble signal of the UE comprises:

receiving a preamble signal which is greater than or equal to a preset threshold.

3. The method of claim 1, wherein the information included in the request message comprises:

recommendation information regarding a transmission beam of the UE or a reception beam of the small cell eNB or location information regarding the UE.

4. The method of claim 3, wherein reordering the order of beams comprises:

preferentially reordering and scanning a reception beam with a relatively high probability of success, based on the location information regarding the UE;

or

preferentially reordering and scanning a recommended beam, based on the recommendation information.

5. A channel access method for a user equipment (UE), connected to a first eNodeB (eNB), to access a second eNB, in a wireless communication system, the method comprising:

measuring a signal strength of beams in each direction formed from the second eNB using a second radio unit while being connected to the first eNB through a first radio unit;

transmitting a measurement report message to the first eNB using the first radio unit, the measurement report message including at least one signal strength of the measured signal strength of beams;

receiving, from the first eNB using the first radio unit, a radio resource control (RRC) connection reconfiguration message for assessing the second eNB;

stopping a data radio bearer (DRB2) with the first eNB through the first radio unit;

identifying whether the measured signal strength of beams is valid based on the received RRC connection reconfiguration message;

transmitting an RRC connection reconfiguration complete message to the second eNB through the second radio unit using a best one of a number of transmission beams through the second radio unit;

transmitting a preamble through a RACH of the second eNB, using the best one of the number of transmission beams through the second radio unit, based on the received RRC connection reconfiguration message; and

communicating with the second eNB using the best one of the number of transmission beams through the second radio unit, if a RACH response (RAR) is received from the second eNB.

6. The method of claim 5, wherein:

the RRC connection reconfiguration message comprises at least one or more recommendation transmission beams to transmit a preamble to the second eNB via the RACH; and

the method further comprises reordering a use order of transmission beams to perform the transmission by preferentially using the recommendation transmission beam.

7. A channel access apparatus of a small cell eNodeB (eNB) in a wireless communication system for supporting a user equipment (UE), in a process of communication with a macro-cell eNB, to perform channel-access to the small cell eNB, in a wireless network capable of using a number of transmission/reception beams, the apparatus comprising:

an antenna unit including a number of antennas for creating a number of transmission/reception beams;

a radio frequency (RF) unit including a number of RF modules for communicating with UEs under the small cell eNB via the antenna unit;

a data processor configured to modulate and decode data to be transmitted to the RF unit and to demodulate and decode data received from the RF unit;

an inter-eNB interface configured to communicate with another eNB, including the macro-cell eNB; and

a scheduler configured to;

receive a request message requesting setup of a channel with the UE from the macro-cell eNB via the inter-eNB interface, set up a data radio bearer (DRB2) to communicate with the UE, and transmit a response (acknowledgement) message to the macro-cell eNB;

receive, from the macro-cell eNB, information related to data to be transmitted to the UE;

reorder an order of reception beams to receive a preamble from the UE via an RACH, based on information included in the request message;

control the RF unit to scan the RACH according to the reordered order of reception beams;

control, when receiving a preamble signal of the UE via the RACH, the data processor and the RF unit to transmit a RACH response signal to the UE; and

perform a procedure for setting up a channel with the UE.

8. The apparatus of claim 7, wherein the information included in the request message comprises:

recommendation information regarding a transmission beam of the UE or a reception beam of the small cell eNB or location information regarding the UE.

9. A channel access apparatus for a user equipment (UE), in a process of communication with a macro-cell eNB, to perform channel access to a small cell eNodeB (eNB) in a wireless network capable of using a number of transmission/reception beams, the apparatus comprising:

an antenna unit including a number of antennas for creating a number of transmission/reception beams;

a radio frequency (RF) unit including a first RF module for communicating with the macro-cell eNB via the antenna unit, and a second RF module for communicating with the small cell eNB via the antenna unit in beamforming scheme;

a data processor configured to modulate and decode data to be transmitted to the RF unit and to demodulate and decode data received from the RF unit; and

a controller configured to;

control the RF unit and the data processor to measure a signal strength of beams in each direction formed from the small cell eNB in a state where the UE is connected to the macro-cell eNB;

transmit a measurement report message to the macro-cell eNB using the first RF module, the measurement report message including at least one signal strength of the measured signal strength of beams;

receive, from the macro-cell eNB using the first RF module, a radio resource control (RRC) connection reconfiguration message for assessing the small cell eNB,

stop a data radio bearer (DRB2) with the macro-cell eNB through the first RF module;

identify whether the measured signal strength of the beams is valid based on the received RRC connection reconfiguration message;

transmit an RRC connection reconfiguration complete message to the small cell eNB through the second RF module using a best one of a number of transmission beams through the second RF module;

transmit a preamble through a RACH of the small cell eNB, using the best one of the number of transmission beams through the second RF module, based on the received RRC connection reconfiguration message; and

communicate with the second eNB using the best one of the number of transmission beams through the second RF module, if a RACH response (RAR) is received from the second eNB.

10. The apparatus of claim 9, wherein:

the RRC connection reconfiguration message comprises at least one or more recommendation transmission beams to transmit a preamble to the small cell eNB via the RACH; and

the controller reorders a use order of transmission beams to perform the transmission by preferentially using the recommendation transmission beam.