# US 11,122,507 B2 · User device for detecting radio link failure in enhanced coverage mode

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- Number: US 11,122,507 B2
- Document ID: US11122507B2
- Status: Granted
- Kind: B2
- Application number: 15/773,300
- Filed: 2016-11-02
- Published: 2018-11-08
- Granted: 2021-09-14
- Earliest claimed: 2015-11-05
- Assignees: Ntt Docomo, Inc.
- Applicants: Ntt Docomo, Inc.
- Inventors: Hideaki Takahashi; Wuri Andarmawanti Hapsari; Kazuaki Takeda
- Web page: https://patentgrep.com/patent/US11122507B2

## CPC

- H04W 52/0245: {according to signal strength}
- H04B 17/328: {Reference signal received power [RSRP]; Reference signal received quality [RSRQ]}
- H04B 17/382: for resource allocation, admission control or handover
- H04W 24/08: Testing, {supervising or monitoring} using real traffic
- H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports}
- H04W 48/16: Discovering, processing access restriction or access information
- H04W 52/0241: {where no transmission is received, e.g. out of range of the transmitter}
- H04W 76/18: Management of setup rejection or failure
- H04W 28/0268: {using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] (negotiating SLA or negotiating QoS H04W28/24)}
- H04W 48/08: Access restriction or access information delivery, e.g. discovery data delivery (signalling during connection H04W76/00)
- H04W 88/02: Terminal devices
- Y02D 30/70: in wireless communication networks
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

An object is to provide a user device and a radio communication method that are capable of appropriately detecting radio link failure (RLF) even when an enhanced coverage mode is in operation. UE (200) includes CE level setting unit (230) that sets, when the UE is set in the enhanced coverage mode, a reception quality threshold (Qin/Qout) of a reference reception power level (RSRP/RSRQ) specified for CE level, and a radio link monitoring unit (240) that executes radio link monitoring based on the set reception quality threshold. The CE level setting unit (230) sets, regardless of whether the UE (200) is set to any CE level or not, a reception quality threshold specified for the maximum CE level.

## Claims

### Claim 1

A user device being configured to set in a first mode that sets a radio link with a radio base station based on a reference reception power level of a radio signal transmitted from the radio base station, and a second mode that sets the radio link based on one of a plurality of reduced levels supported by the radio base station and having gradually reduced reference reception power levels than the reference reception power level used in the first mode, the user device comprising:
a processor coupled to a memory that sets, when the user device is set in the second mode, a reception quality threshold of the reference reception power level specified for a maximum reduced level among the plurality of reduced levels supported by the radio base station,
wherein the processor executes monitoring of the radio link based on the reception quality threshold, and
wherein, when the user device is in the second mode and executes a reduced level that is different from the maximum reduced level supported by the radio base station, the processor sets the reception quality threshold specified for the maximum reduced level supported by the radio base station.

### Claim 2

A user device being configured to set in a first mode that sets a radio link with a radio base station based on a reference reception power level of a radio signal transmitted from the radio base station, and a second mode that sets the radio link based on one of a plurality of reduced levels having gradually reduced reference reception power levels than the reference reception power level used in the first mode, the user device comprising:
a processor coupled to a memory that measures the reference reception power level that corresponds to the reduced level,
wherein the processor sets, when the user device is set in the second mode, a reception quality threshold of the measured reference reception power level, the reception quality threshold being specified for a maximum reduced level among the plurality of reduced levels supported by the radio base station,
wherein the processor measures a reception power level of the radio signal, and executes monitoring of the radio link based on the reception quality threshold, and
wherein, when the user device is in the second mode and executes another or the other reduced level that is different from the maximum reduced level, corresponding to the measured reception power level and for which the reception quality threshold is specified, the processor sets the reception quality threshold specified for the maximum reduced level corresponding to the measured reception power level measured by the processor regardless of a reduced level set for the user device.