628 results about "Radio link failures" patented technology

An apparatus and method in a heterogeneous wireless communication system reconnect a Mobile Station (MS) to a previously connected cell upon occurrence of a Radio Link Failure (RLF) in a current cell when a portion of a coverage of the second cell is included in a coverage of the first cell. A Mobile Station (MS) stores system information of a first Base Station (BS) of a first cell when performing handover from the first cell to a second cell. When changed system information of the first BS is received from a second BS of the second cell, the MS updates the stored system information using the changed system information. When detecting that a connection with the second cell is lost prior to a handover from the second cell, the MS performs reconnection to the first BS using the stored system information.

Certain aspects of the present disclosure relate to techniques for managing radio link failure recovery for a user equipment (UE) connected to a WWAN and a WLAN. The techniques may include establishing communication with a first radio access technology (RAT) and a second RAT. At least one data flow may be transmitted over each of the first RAT and the second RAT. Determinations may be made as to whether to maintain the at least one data flow over the second RAT when a radio link failure (RLF) is detected at the UE and / or whether to resume the at least one data flow over the second RAT upon RLF recovery. The determinations may be made at the UE, at a network entity in communication with the UE, or some combination thereof.

An apparatus for facilitating handover failure recovery may include a handover management element configured to receive, at a target node, a handover request from a source node regarding the handover of communications with a mobile terminal. The handover request may include identity information indicative of the mobile terminal. The identity information may be the identity information used to identify the mobile terminal to the source node during establishment of the original connection between the source node and the mobile terminal. The handover management element may be further configured to receive a request for a connection from the mobile terminal subsequent to a radio link failure and prior to handover completion. Based on matching the identity information from the request for connection and the identity information received from the source node, the target node may establish communication with the mobile terminal based on access stratum configuration information used by the source node.

A terminal, a Base Station (BS) and a method for detecting a cause of a Radio Link Failure (RLF) or handover failure are provided. The method includes determining whether an RLF or a handover failure occurs, performing a process of a connection re-establishment or connection establishment to enter a connection mode after encountering the RLF or the handover failure, and transmitting an RLF information report to a BS after entering the connection mode.

When a mobile terminal experienced a radio link failure in a first cell and establishes a re-connection in a second cell within a predefined time and / or within a preset movement distance from the time of the radio link failure, the mobile terminal reports at least one of the information regarding a first cell and the information regarding a second cell.

A method of handling random access procedure failure for a user equipment in a radio resource control connected state in a wireless communication system includes initiating a random access procedure corresponding to uplink or downlink data arrival, and then, when the random access procedure fails, determining that a radio link failure is detected and performing a radio link recovery procedure.

A method of handling radio link failure (RLF) for a communication device in a wireless communication system is disclosed. The method comprises connecting to at least two base stations including a first base station and a second base station in the wireless communication system, detecting RLF on the first base station, and sending a RLF cause report associated to the first base station to the second base station.

A method of radio link monitoring (RLM) and radio link failure (RLF) handling over a secondary serving cell (SCELL) is proposed. In a wireless network, a user equipment (UE) establishes a radio resource control (RRC) connection with a base station (eNB). The UE applies carrier aggregation for multiple component carriers (CCs) configured as multiple serving cells. The UE performs radio link monitoring over a primary serving cell (PCELL). The UE also performs radio link monitoring over a secondary serving cell (SCELL). The SCELL belongs to a CC group of one or more CCs, and used as a reference cell for the CC group. When SCELL performance is below pre-defined criteria, the UE and the eNB apply certain actions over the SCELL or all CCs in the CC group. The proposed SCELL RLM / RLF handling prevents spurious and uncontrollable uplink SCELL transmission and interference to other UEs.

A user equipment (UE) monitors coexistence issues of one or more associated communication resources. The UE initiates link recovery procedures (e.g., declaring a Radio Link Failure (RLF)) in response to the monitoring when a coexistence issue is detected. The UE can also access a new channel or a new Radio Access Technology (RAT) in response to initiating the link recovery. The network may have the ability to control whether the UE can initiate the link recovery.

A Base Station (BS) apparatus, for detecting a HandOver (HO)-related Radio Link Failure (RLF) in a wireless communication, and method for its operation, are provided. The method includes receiving an HO request from another BS for a User Equipment (UE) that has an established connection with the BS, receiving a connection reestablishment request from the UE after an HO of the UE to the other BS has been performed, determining if the connection reestablishment request is received prior to the expiration of a timer, and if it is determined that the connection reestablishment request is received from the UE prior to the expiration of a timer, determining that an RLF occurred due to a too early HO triggering.

Methods and apparatuses are provided for performing multi-eNB connectivity communication. An eNB receives a Radio Link Failure (RLF) expected message related to a first link, from a UE. A target cell is sought for a handover of the UE according to the RLF expected message. The target cell is selected, when the target cell is found. The eNB receives, from the UE, an RLF message related to the first link, through a second link. An instruction for the handover to the selected target cell is transmitted to the UE.

A method and apparatus of handling a radio link failure in a wireless communication system is provided. Upon detecting a radio link failure in a Radio Resource Control (RRC) connected state, a user equipment starts a radio link failure timer of which timer value is selected among at least one timer value for at least one RB. The user equipment attempts a RRC connection re-establishment while the radio link failure timer is running, and transitions to a RRC idle state when the radio link failure timer is expired.

The invention discloses a method for handling radio link failure, comprising the following steps that: a relay node (RN) detects RLF (radio link failure) of an Un interface according to a preset RLF detection judging condition; the RN chooses to return back to a radio resource control (RRC) idle state when detecting that the UN interface has RLF, and rebuilds a RRC connection of the Un interface performing a random access operation again, or chooses to recover the RRC connection of the Un interface through a RRC connection rebuilding program under a RRC connection state. The invention further discloses a relay node. With the method and the relay node provided by the invention, effective detection on the RLF of the Un interface by the RN is implemented, and the RLF is handled well.

A method and system for improving a call drop caused by a Radio Link Failure (RLF) before handover triggering in a mobile communication system are provided. The method of improving the call drop caused by the RLF in the mobile communication system includes detecting an RLF occurring before handover triggering (RLF_before_HO), generating one of an RLF_before_HO-dependent statistics and an RLF_before_HO-dependent log file, transmitting the one of the RLF_before_HO-dependent statistics and the RLF_before_HO-dependent log file to a serving Base Station (BS), and updating a Neighbor Relation Table (NRT) and optimizing a handover parameter using the one of the RLF_before_HO-dependent statistics and the RLF_before_HO-dependent log file.

The embodiment of the invention discloses a method and a device for processing radio link failure under a carrier aggregation scene, which can ensure that user equipment (UE) can reconstruct radio resource control (RRC) connection in time. One method provided by the invention comprises the following steps of: when the radio link failure of at least one downlink carrier is detected, or the radio link failure of at least one uplink carrier is detected, or the physical layer problem of at least one carrier is detected, or the random access failure of a random access channel (RACH) of at least one carrier is detected, starting radio link normality or failure judgment of all carriers, and / or starting a first timer. The other method provided by the invention comprises the following step of: when the need of RRC connection reconstruction is judged, selecting a carrier in a service aggregation cell or selecting a low-frequency carrier in the service aggregation cell to initiate an RRC signaling connection request.

The invention discloses a method and user equipment (UE) for measuring and feeding back channel quality, which is used for solving the problem that a cell edge user (CEU) and a radio link failure (RLF) can not be distinguished accurately caused by incomplete reference signal receiving power (RSRP) and / or reference signal receiving quality (RSRQ) information and the problem of certain influence on link adaptive performance caused by only feeding back one channel quality indication (CQI) in the prior art. According to the technical scheme of the invention, the UE measures and feeds back the RSRP and / or RSRQ information and channel quality indication (CQI) information of subframes which are almost fully empty subframes corresponding to strong interference neighbor cells and the RSRP and / or RSRQ and channel quality indication (CQI) information of subframes which are normally transmitted subframes corresponding to the strong interference neighbor cells, thereby solving the problem of accurately distinguishing a cell center user (CCU) and the CEU in a heterogeneous network and preventing the RLF phenomenon. In addition, the invention can enable users to obtain better link adaptability according to the CQI of different types of subframes when data is transmitted on different subframes, thereby improving the system throughput.

A method and a system for processing a Radio Link Failure (RLF) report, where when a User Equipment (UE) encounters an RLF in a first cell controlled by a first evolved base station and selects a second cell controlled by a second evolved base station to re-establish an Radio Resource Connection (RRC), are provided. The method includes sending, by the second evolved base station, the RLF report to every corresponding evolved base station according to the PCI of the first cell having been received from the UE, where the PCI of the first cell, the PCI of a second cell, the CRNTI of the UE in the first cell, and UE authentication information are carried in the RLF report, and authenticating, by every evolved base station the UE according to the UE authentication information. Another method for processing an RLF report, and two methods for adjusting a mobile parameter, are also provided.

A wireless transmit / receive unit (WTRU) (152) in a wireless communications system includes a transceiver (153) for transmitting and receiving data from a plurality of base stations (154, 156, 357) and a controller (151) communicatively coupled to the transceiver (153) and configured to adjust an operation mode of the transceiver (153). In the WTRU (152), adjusting comprises configuring the transceiver (153) to begin a radio link handover procedure responsive to receiving a handover (HO) command from a first of the plurality of base stations (154, 156, 357) over a first communications link, specifying a first time, and reconfiguring the transceiver (153) to begin a radio link interruption procedure responsive to an expiry of the first time prior to completion of the radio link handover procedure. In the WTRU (152), the radio link interruption procedure first attempts to re-establish the first communications link.

A method (300) and apparatus (200) for radio link failure recovery is disclosed. The method may include detecting (320) the presence of an intra-frequency neighbor base station (145) of a serving base station (135). The method may include determining (330) that a radio link parameter of an inter-frequency neighbor base station is better than a threshold. The method may include acquiring (350) system information of the inter-frequency neighbor base station if the intra-frequency neighbor base station is present and if the radio link parameter of the inter-frequency neighbor base station is better than the threshold.

The invention provides a method for a main base station in a dual-connectivity system. The method comprises the following steps of receiving an indication to an S-RLF, a trigger reason and a measuring report of the S-RLF from user equipment UE in case of a radio link failure of a supplementary base station (the S-RLF); determining operations on the supplementary base station on the basis of the indication, the trigger reason and the measuring report; and informing the UE of the determined operations on the supplementary base station. The invention further provides a method for the user equipment in the dual-connectivity system, the related main base station and user equipment. The invention further provides an optimized solution scheme for a UE operation process in the dual-connectivity system when the S-RLF is detected. The scheme includes a process of MAC / RLC / PDCP layers, signals between the UE and the main base station and signals between the main base station and the supplementary base station. In this way, the UE behavior is clearly defined and optimized. The dual-connectivity system is thus enabled to work with higher efficiency in case of an S-RLF condition.

Disclosed is a method for radio link monitoring in a wireless communication system and an apparatus for the method. More specifically, a method for a user equipment (UE) to perform Radio Link Monitoring (RLM) in a wireless communication system comprises performing second RLM on a cell based on a Reference Signal (RS) other than a Cell-specific Reference Signal (CRS) and determining an Radio Link Failure (RLF) with respect to the cell based on the second RLM, wherein a condition for determining an RLF applied to the second RLM is different from the condition for determining an RLF applied to CRS-based first RLM.

A method and an apparatus for wireless link (radio link) control in a wireless communication system supporting dual connectivity is disclosed. The present invention includes: detecting radio link failure (RLF) of a secondary serving cell provided from a secondary base station, separately from detecting RLF of a primary serving cell provided from a master base station; generating a RLF specifier specifying an occurrence of RLF of the secondary serving cell when RLF of the secondary serving cell is detected; and transmitting the RLF specifier to an RRC connected master base station. A wireless link between a terminal and a master base station and a wireless link between a terminal and a secondary base station can be managed individually when a terminal is dually connected to both the master base station and the secondary base station in a network.

A mobile communications device is provided with a wireless module and a controller module. The wireless module receives a plurality of downlink signals from a service node and determines a plurality of status indicators respectively corresponding to the downlink signals. The controller module determines whether a radio link failure has occurred according to the status indicators, and transmits at least one uplink signal via the wireless module to indicate information of the radio link failure to the service node in response to the occurrence of the radio link failure.

A wireless communication network and method are described for enhancing cell-edge performance of a wireless transmit / receive unit (WTRU). The WTRU may establish a connection with a plurality of sites via respective downlinks (DLs). Each DL may include at least one DL component carrier (CC) that operates on a frequency that is the same or different than one or more of the other CCs. The sites may manipulate their transmit power for a particular CC operating frequency such that the distance from a particular one of the sites to its cell boundary may become larger by increasing its transmit power on the particular frequency, and the distance from at least one of the other sites to its respective cell boundary may become smaller by decreasing its transmit power on the particular frequency. Thus, a coverage overlap between different CC frequencies may be created while maintaining a frequency reuse pattern of one.

There is proposed a mechanism for controlling a radio link failure recovery procedure in a communication network having relay nodes, wherein a network control node, such as a DeNB, forwards cached UE context information to a target network node which is contacted by an UE for re-establishment after radio link failure and requests, since it does not have the context information, the context information for the UE in question. Context information can also be proactively forwarded from the network control node to candidate neighboring network nodes when it is detected that a radio link failure between a relay node and the network control node, or between the relay node and a UE is possible.

A system and method in which a Radio Link Failure, RLF, report from a User Equipment, UE, provides system time-based timestamps to enable a source node to correctly analyze the real cause of an RLF associated with a handover. The timestamps are provided for the latest fulfillment of each event-specific entering condition associated with a handover-triggering event and for the occurrence of the RLF. The recorded timestamps are sent as part of RLF-reporting information to be forwarded to the source node to assist the source node in adjusting event-specific threshold(s) as well as other non-threshold related handover parameters such as the Time To Trigger, TTT, period, the time delay between a UE's transmission of its Measurement Report and the source node's transmission of the handover command, and the like, to reduce similar RLFs in the future. The generation of timestamps does not waste the UE's processing resources or battery power.

Attempting recovery from an unexpected radio link failure. A backup user context is created for a terminal device served currently by a relay base station relaying a radio connection between the terminal device and fixed cellular network infrastructure including a fixed base station communicating with the relay base station, wherein the backup user context is prepared for use in case of an unexpected radio link failure. Upon detection of the radio link failure in a primary user context being used in the communication, the backup user context is applied before the terminal device enters an idle state as a result of the radio link failure.

A communication device of handling a communication operation with a first base station and a second base station comprises a storage unit for storing instructions and a processing means coupled to the storage unit. The processing means is configured to execute the instructions stored in the storage unit. The instructions comprise performing a communication operation with the second base station via a radio bearer configured as a SCG bearer; detecting a radio link failure on a cell of the second base station or a SCG change failure; suspending the radio bearer and transmitting a SCG failure information message in response to the detection of the radio link failure to the first base station; receiving a radio resource control (RRC) message configuring the radio bearer as a MCG bearer from the first base station; and resuming the second radio bearer in response to the reception of the RRC message.

The present disclosure relates to a terminal operation method related to radio link failure (RLF) in a heterogeneous network, the method comprising: measuring a quality of a serving cell using a reference signal (RS) received from a serving base station; checking whether consecutive out-of-sync indications are received a predetermined number on a physical layer channel; and running a timer related to the RLF when the consecutive out-of-sync indications are received the predetermined number on the physical layer channel, wherein the timer is scaled when a timer scaling condition is met.