User equipment and beam failure recovery method
11483055 · 2022-10-25
Assignee
Inventors
Cpc classification
H04W24/08
ELECTRICITY
International classification
Abstract
The present invention provides user equipment and a beam failure recovery method. The beam failure recovery method for user equipment (UE), includes: receiving indication of beam failure instance; accumulating the number of received indications so as to obtain an accumulative value; initiating a beam failure recovery procedure when the accumulative value is greater than a first threshold; and skipping processing the received indication of beam failure instance during the beam failure recovery period. Thus, it is possible to eliminate false beam failures.
Claims
1. A method performed by user equipment, comprising: receiving a beam failure instance indication from lower layers; incrementing a counter for the beam failure instance indication by 1, on the basis of a determination that the beam failure instance indication has been received from lower layers; resetting the counter to 0 if no beam failure instance indication is received within a time threshold; and initiating a random access procedure if the counter exceeds a specific value.
2. A user equipment, comprising; a processor; and a memory in electronic communication with the processor, wherein, instructions stored in the memory are executable to: receive a beam failure instance indication from lower layers; increment a counter for the beam failure instance indication by 1, on the basis of a determination that the beam failure instance indication has been received from lower layers; reset the counter to 0 if no beam failure instance indication is received within a time threshold; and initiate a random access procedure if the counter exceeds a specific value.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) The above and other features of the present invention will be more pronounced through the following detailed description taken in conjunction with the accompanying drawings.
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
DETAILED DESCRIPTION OF EMBODIMENTS
(15) The following describes the present invention in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention is not limited to the specific embodiments described below. In addition, for simplicity, detailed description of the known art not directly related to the present invention is omitted to prevent confusion with respect to the understanding of the present invention.
(16) In the following description, a 5G mobile communication system and its subsequently evolved versions are used as illustrative application environments to set forth a plurality of embodiments according to the present invention in detail. However, it is to be noted that the present invention is not limited to the following embodiments, and rather, it is applicable to many other wireless communication systems, such as a communication system later than 5G and a 4G mobile communication system earlier than the 5G.
(17) Some terms involved in the present invention are described below. Unless otherwise specified, the terms used in the present invention adopt the definitions herein. The terms given in the present invention may be named differently in LTE, LTE-Advanced, LTE-Advanced Pro, NR, and later communication systems, but unified terms are adopted in the present invention. When applied to a specific system, the terms may be replaced with terms adopted in the corresponding system.
(18) LTE-A: Long Term Evolution-Advanced
(19) UE: User Equipment
(20) CSI-RS: Channel State Information-Reference Signal
(21) RE: Resource Element
(22) CP-OFDM: Cyclic Prefix-Orthogonal Frequency Division Multiplexing
(23) DFT-s-OFDM: Discrete Fourier Transform-spread-Orthogonal Frequency Division Multiplexing
(24) RS: Reference Signal
(25) NR: New Radio
(26) EPRE: Energy Per Resource Element
(27) PSS: Primary Synchronization Signal
(28) SSS: Secondary Synchronization Signal
(29) PBCH: Physical Broadcast Channel
(30) RRC: Radio Resource Control
(31) MAC: Medium Access Control
(32) DCI: Downlink Control Information
(33) In one embodiment of the present invention, a beam failure recovery timer (beamFailureRecoveryTimer) is utilized to eliminate false beam failures.
(34) In this embodiment, if the timer beamFailureRecoveryTimer is not running, then the related processing of beam failure detection and recovery is performed. For example, when the MAC layer entity of the UE receives an indication of “beam failure instance” from the lower layers, the number of received indications is accumulated so as to obtain an accumulative value, and for another example, the beam failure recovery procedure is initiated when the accumulative value is greater than a first threshold (Beam-Failure-Instance-MaxCount). These processes are not performed if the timer beamFailureRecoveryTimer is running
(35) For example, using the language in the MAC protocol, the scheme can be described as follows:
(36) TABLE-US-00004 1> if a beam failure instance has been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> increment Beam-Failure-Instance-Count by 1; 2> if Beam-Failure-Instance-Count exceeds Beam-Failure-Instance-MaxCount: 3> reset Beam-Failure-Instance-Count; 3> start beamFailureRecoveryTimer; 3> initiate a Random Access procedure.
(37)
(38) As shown in
(39) In this embodiment, as shown in
(40) As described above, in an embodiment of the present invention, in the user equipment (UE), when an indication of beam failure instance is received, the number of received indications is accumulated so as to obtain an accumulative value, and when the accumulative value is greater than the first threshold, the beam failure recovery procedure is initiated. During the beam failure recovery period, the received indication of beam failure instance is not processed, and accumulation is not performed.
(41) According to this embodiment, it is monitored whether it is in the beam failure recovery period, and if it is in the beam failure recovery period, the received beam failure instance(s) may be meaningless, and it is not necessary to continue the beam failure determination. With the existing determination beam failure recovery timer, false beam failures received during the beam failure recovery period can be eliminated.
(42) In the following, when specific examples are provided to illustrate other preferred embodiments of the present invention, description is provided by using the example where the timer beamFailureRecoveryTimer is used to determine whether it is in the beam failure recovery period or not and further processing is performed while it is not in the beam failure recovery period. Certainly, the following specific examples and embodiments may not perform such determination of the beam failure recovery period. Further, for the method of determining the beam failure period, other methods may be adopted for such determination without using the timer beamFailureRecoveryTimer.
(43) In the following, specific examples are provided to illustrate the other preferred embodiments of the present invention.
Example 1
(44) In this example, the MAC layer entity of the UE defines a beam failure instance timer beamFailureInstanceTimer. The timer value set when the timer is initiated can be a fixed value or a parameter configured by an upper layer protocol.
(45) When the MAC layer entity of the UE receives an indication of “beam failure instance” from the lower layers, the following steps are performed: If the timer beamFailureRecoveryTimer is not running, and the timer beamFailureInstanceTimer is running, then the timer beamFailureInstanceTimer is stopped and reset; If the timer beamFailureRecoveryTimer is not running and the accumulative value of the beam failure instance counter Beam-Failure-Instance-Count exceeds the Beam-Failure-Instance-MaxCount, then the beam failure recovery procedure is initiated.
(46) If the timer beamFailureInstanceTimer expires, then the value of the beam failure instance counter Beam-Failure-Instance-Count may be adjusted through one of the following two methods:
(47) Method 1: reset the beam failure instance counter Beam-Failure-Instance-Count (i.e., set the Beam-Failure-Instance-Count=0).
(48) Method 2: adjust the value of the beam failure instance counter Beam-Failure-Instance-Count through one of the following two formulas:
(49) Beam-Failure-Instance-Count=floor(delta*Beam-Failure-Instance-Count)+1, or
(50) Beam-Failure-Instance-Count=ceil(delta*Beam-Failure-Instance-Count)+1, where
(51) floor (.) is a function, and the function value thereof is the largest integer that is not greater than the independent variable; ceil (.) is a function, and the function value thereof is the smallest integer that is not less than the independent variable; delta may be a fixed value or a parameter configured by an upper layer protocol. Delta is used to set the weight of the historical count value of Beam-Failure-Instance-Count in the updated count value.
(52) In the present invention, if the timer expires, the operation is automatically stopped; and if the timer is stopped before expiration, then the timer may be processed in the following two methods:
(53) Method 1: the timer is stopped, and the timer value is reset; and when initiated next time, the timer is initiated with the initial value;
(54) Method 2: the timer is stopped, and the timer value is retained; and when initiated next time, the timer is initiated with the timer value retained when stopped last time.
(55) This processing manner for the timer will also be the same in the following examples or embodiments.
(56) For example, using the language in the MAC protocol, the scheme can be described as follows:
(57) TABLE-US-00005 1> upon RRC connection establishment: 2> initiate Beam-Failure-Instance-Count to 0; ... 1> if a beam failure instance has been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> stop beamFailureInstanceTimer; 2> increment Beam-Failure-Instance-Count by 1; 2> if Beam-Failure-Instance-Count exceeds Beam-Failure-Instance-MaxCount: 3> reset Beam-Failure-Instance-Count; 3> start beamFailureRecoveryTimer; 3> initiate a Random Access procedure. 2> else: 3> start beamFailureInstanceTimer; ... 1> if the beamFailureInstanceTimer expires: 2> reset Beam-Failure-Instance-Count.
(58)
(59) As shown in
(60) In this example, as shown in
(61) In this example, when the count value of the beam failure instance counter is adjusted, either one of the above two methods may be adopted, or other methods may be adopted.
(62) As described above, in an embodiment of the present invention, in the user equipment (UE), when an indication of beam failure instance is received, the number of received indications is accumulated so as to obtain an accumulative value, and when the accumulative value is greater than the first threshold, the beam failure recovery procedure is initiated. If no other indication is received within a time duration equal to a second threshold since the reception of the indication, the accumulative value is adjusted.
(63) According to this embodiment, the elapsed time since the occurrence of the most recent beam failure instance is monitored, and if the time is too long, it is an indication that the previously accumulated beam failure instances may have already been meaningless, and it is not necessary to use them for the determination of the subsequent beam failure(s). Through adjusting the accumulative value of the beam failure instances when the elapsed time since the occurrence of the most recent beam failure instance exceeds a threshold, false beam failures can be eliminated.
Example 2
(64) In this example, the MAC layer entity of the UE defines a beam failure reset timer beamFailureResetTimer. The timer value set when the timer is initiated can be a fixed value or a parameter configured by an upper layer protocol.
(65) When the beam failure instance counter (Beam-Failure-Instance-Count) is initialized (e.g., when the RRC connection is established), the timer beamFailureResetTimer is initiated. In addition, the timer beamFailureResetTimer can also be initiated when the beam failure recovery fails, or initiated by an upper layer indication.
(66) When the MAC layer entity of the UE receives an indication of “beam failure instance” from the lower layers, if the timer beamFailureRecoveryTimer is not running, and the accumulative value of the beam failure instance counter Beam-Failure-Instance-Count exceeds the Beam-Failure-Instance-MaxCount (in other words, the UE determines that a beam failure has occurred, and then beam failure related processing is to be performed), and if the timer beamFailureResetTimer is running, then the timer beamFailureResetTimer is stopped and reset.
(67) If the timer beamFailureResetTimer expires, the timer beamFailureResetTimer is reinitiated, and then the beam failure instance counter Beam-Failure-Instance-Count is adjusted through one of the following two methods:
(68) Method 1: reset the beam failure instance counter Beam-Failure-Instance-Count (i.e., set the Beam-Failure-Instance-Count=0).
(69) Method 2: adjust the value of the beam failure instance counter Beam-Failure-Instance-Count through one of the following two formulas:
Beam-Failure-Instance-Count=floor(delta*Beam-Failure-Instance-Count)+1, or
Beam-Failure-Instance-Count=ceil(delta*Beam-Failure-Instance-Count)+1, where
(70) floor (.) is a function, and the function value thereof is the largest integer that is not greater than the independent variable; ceil (.) is a function, and the function value thereof is the smallest integer that is not less than the independent variable; delta may be a fixed value or a parameter configured by an upper layer protocol. Delta is used to set the weight of the historical count value of Beam-Failure-Instance-Count in the updated count value.
(71) For example, using the language in the MAC protocol, the scheme can be described as follows:
(72) TABLE-US-00006 1> upon RRC connection establishment: 2> initiate Beam-Failure-Instance-Count to 0; 2> start beamFailureResetTimer; ... 1> upon unsuccessful beam failure recovery: 2> initiate Beam-Failure-Instance-Count to 0; 2> start beamFailureResetTimer; ... 1> if a beam failure instance has been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> increment Beam-Failure-Instance-Count by 1; 2> if Beam-Failure-Instance-Count exceeds Beam-Failure-Instance-MaxCount: 3> reset Beam-Failure-Instance-Count; 3> start beamFailureRecoveryTimer; 3> stop beamFailureResetTimer; 3> initiate a Random Access procedure. ... 1> if the beamFailureResetTimer expires: 2> reset Beam-Failure-Instance-Count; 2> start beamFailureResetTimer.
(73) This scheme can also be described as follows using the language in the MAC protocol. X may be equal to Beam-Failure-Instance-MaxCount, and “more than X consecutive beam failure instances” may also be written as “Y consecutive beam failure instances,” where Y may be equal to Beam-Failure-Instance-MaxCount+1.
(74) TABLE-US-00007 1> upon RRC connection establishment: 2> initiate the counter used for consecutive beam failure instances to 0; 2> start beamFailureResetTimer; ... 1> upon unsuccessful beam failure recovery: 2> initiate the counter used for consecutive beam failure instances to 0; 2> start beamFailureResetTimer; ... 1> if more than X consecutive beam failure instances have been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> start beamFailureRecoveryTimer; 2> stop beamFailureResetTimer; 2> initiate a Random Access procedure. ... 1> if the beamFailureResetTimer expires: 2> reset the counter used for consecutive beam failure instances; 2> start beamFailureResetTimer.
(75)
(76) As shown in
(77) Then, the process proceeds to Step S203, where it is determined whether the count value of the beam failure instance counter exceeds a threshold (Beam-Failure-Instance-MaxCount). If the determination in Step S203 is “NO,” then the process is ended. If the determination in Step S203 is “YES,” then the count value of the beam failure instance counter is adjusted (Step S204), and the beam failure recovery timer is initiated (Step S205). Then, it is determined whether the beam failure reset timer (beamFailureResetTimer) is running (Step S206); if the determination is “YES,” then the beam failure reset timer is stopped (Step S207), and then the process proceeds to Step S208; and if it is determined that the beam failure reset timer is not running (Step S206, “NO”), then the process proceeds to Step S208 to initiate the beam failure recovery process (such as performing random access, etc.).
(78) When the count value of the beam failure instance counter is adjusted, either one of the above two methods may be adopted, or other methods may be adopted.
(79) In this example, as shown in
(80) In this example, when the count value of the beam failure instance counter is adjusted, either one of the above two methods may be adopted, or other methods may be adopted.
(81) As described above, in an embodiment of the present invention, in the user equipment (UE), when an indication of beam failure instance is received, the number of received indications is accumulated so as to obtain an accumulative value; when the accumulative value is greater than the first threshold, the beam failure recovery procedure is initiated; if the accumulative value accumulated within a given time, i.e., within the range of the second threshold is not greater than the first threshold, then the accumulative value is adjusted.
(82) According to this embodiment, the total time for occurrences of Beam-Failure-Instance-MaxCount “beam failure instances,” which is required to satisfy the “beam failure” conditions, can be limited within a certain range. If the value of the beam failure instance counter does not reach Beam-Failure-Instance-MaxCount within a given time, the value of the counter is adjusted, e.g., reset to zero, to proceed to a next evaluation cycle. Thus, it is possible to eliminate false beam failures.
Example 3
(83) In this embodiment, the MAC layer entity of the UE defines a beam failure declaration timer beamFailureDeclarationTimer. The timer value set when the timer is initiated can be a fixed value or a parameter configured by an upper layer protocol.
(84) In this example, the physical layer entity of the UE indicates a “beam success instance” to the MAC layer entity of the UE when certain conditions are met. These conditions may include:
(85) 1. the measured values of all reference signals used for beam failure measurement (expressed as an error probability) are all less than a predetermined threshold;
(86) 2. one or more of the measured values of reference signals used for beam failure measurement (expressed as an error probability) are less than a predetermined threshold;
(87) 3. the UE detects, in the configured CORESET, at least one instance of DCI transmitted to the UE (i.e., the DCI is scrambled by the C-RNTI allocated to the UE). The configured control resource set may be an operating control resource set, or a control resource set specially configured for beam failure recovery, or a combination of the two.
(88) When the MAC layer entity of the UE receives more than Beam-Success-Instance-MaxCount (Beam-Success-Instance-MaxCount may be 1, or other fixed positive integer values, or a configurable RRC parameter) consecutive indications of “beam success instances,” and if the timer beamFailureRecoveryTimer is not running, and if the timer beamFailureDeclarationTimer is running, then the timer beamFailureDeclarationTimer is stopped and reset.
(89) When the MAC layer entity of the UE receives more than Beam-Failure-Instance-MaxCount (Beam-Success-Instance-MaxCount may be 1, or other fixed positive integer values, or a configurable RRC parameter) consecutive indications of “beam failure instances,” and if the timer beamFailureRecoveryTimer is not running, then the timer beamFailureDeclarationTimer is initiated.
(90) If the timer beamFailureDeclarationTimer expires (when this condition is met, it is considered that a beam failure has occurred), then the timer beamFailureRecoveryTimer is initiated, and a beam failure recovery request is initiated (e.g., a random access procedure is initiated to transmit a “beam failure recovery request” to a base station).
(91) For example, using the language in the MAC protocol, the scheme can be described as follows:
(92) TABLE-US-00008 1> if Y consecutive beam failure instances have been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> start beamFailureDeclarationTimer; 1> if X consecutive beam success instances have been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> stop beamFailureDeclarationTimer 1> if the beamFailureDeclarationTimer expires; 2> start beamFailureRecoveryTimer; 2> initiate a Random Access procedure.
(93) For another example, this scheme can also be described as follows using the language in the MAC protocol:
(94) TABLE-US-00009 1> if a beam failure instance has been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> increment Beam-Failure-Instance-Count by 1; 2> if Beam-Failure-Instance-Count exceeds Beam-Failure-Instance-MaxCount: 3> start beamFailureDeclarationTimer; ... 1> if a beam success instance has been received from lower layers, and; 1> if beamFailureRecoveryTimer is not running: 2> increment Beam-Success-Instance-Count by 1; 2> if Beam-Success-Instance-Count exceeds Beam-Success-Instance-MaxCount: 3> stop beamFailureDeclarationTimer; ... 1> if the beamFailureDeclarationTimer expires; 2> reset Beam-Failure-Instance-Count; 2> reset Beam-Success-Instance-Count; 2> start beamFailureRecoveryTimer; 2> initiate a Random Access procedure.
(95)
(96) In this example, as shown in
(97) As shown in
(98) Then, the process proceeds to Step S307, where it is determined whether the count value of the beam failure instance counter exceeds a threshold (Beam-Failure-Instance-MaxCount). If the determination in Step S307 is “NO,” then the process is ended. If the determination in Step S307 is “YES,” then the beam failure declaration timer is initiated (Step S308).
(99) As shown in
(100) Then, the process proceeds to Step S313, where it is determined whether the count value of the beam success instance counter exceeds a threshold (Beam-Success-Instance-MaxCount). If the determination in Step S313 is “NO,” then the process is ended. If the determination in Step S313 is “YES,” then the beam failure declaration timer is stopped (Step S314).
(101) In this example, as shown in
(102) As described above, in an embodiment of the present invention, in the user equipment (UE), when an indication of beam failure instance is received, the number of received indications is accumulated so as to obtain an accumulative value; and timing is started when the accumulative value reaches the first threshold, and the beam failure recovery procedure is initiated when the elapsed time is greater than or equal to a given time, i.e., the second threshold. In addition, preferably, when an indication of beam success instance is received, the number of received indications of beam success instance is accumulated so as to obtain an accumulative value; and when the accumulative value is greater than or equal to a third threshold, timing of the elapsed time is stopped.
(103) According to this embodiment, the “beam failure instance” and the “beam success instance” can be independently counted, and the “beam failure instance” can be cleared according to the accumulative result of the “beam success instance.” Thus, it is possible to eliminate false beam failures.
(104)
(105) Each of the above-described examples and embodiments can be combined with each other if no contradiction is caused. For example, it is possible to arbitrarily combine the case considering the elapsed time since the occurrence of the most recent beam failure instance, the case considering that the value of the beam failure instance counter cannot reach the threshold within a given time, and the case considering the beam success instances. Through combining any of the examples and the embodiments arbitrarily, it is possible to further eliminate false beam failures.
(106) Further, in the present invention, in some examples, receiving an indication of beam failure instance may be consecutively receiving indications of beam failure instance; and additionally, receiving indication of beam success instance may be consecutively receiving indications of beam success instance.
(107) Herein, in the case of consecutively receiving indications of beam failure instance, for two given indications of beam failure instance, it is considered these two indications of beam failure instance are consecutive only when no other indication of beam failure instance or indication associated with the beam failure instance (e.g., indication of beam success instance) occurs between the points-in-time of these two indications. In this case, only the instances of beam failures that are consecutively received are accumulated.
(108) In the case of consecutively receiving indications of beam success instance, for two given indication of beam success instance, it is considered these two indications of beam success instance are consecutive only when no other indication of beam success instance or indication associated with the beam success instance (e.g., indication of beam failure instance) occurs between the points-in-time of these two indications. In this case, only the instances of the beam successes that are consecutively received are accumulated.
(109) The methods and related devices according to the present invention have been described above in conjunction with the preferred embodiments. It should be understood by those skilled in the art that the methods shown above are only exemplary. The method of the present invention is not limited to steps or sequences illustrated above. The network node and the user equipment illustrated above may include more modules; for example, they may further include modules which can be developed or developed in the future to be applied to modules of a base station, an MME, or UE. Various identifiers shown above are only exemplary, and are not meant for limiting the present invention. The present invention is not limited to specific information elements serving as examples of these identifiers. Those skilled in the art can make various alterations and modifications according to the teachings of the illustrated embodiments.
(110) It should be understood that the embodiments above of the present invention can be implemented by software, hardware or a combination of the software and the hardware. For example, various components inside the base station and the user equipment in the embodiments above can be implemented by various devices, and these devices include, but are not limited to: an analog circuit device, a digital circuit device, a Digital Signal Processor (DSP) circuit, a programmable processor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Complex Programmable Logic Device (CPLD) and the like.
(111) In the present application, the term “base station” refers to a mobile communication data and control switching center with a larger transmit power and a wider coverage area, and has functions of resource distribution scheduling, data receiving and transmitting, and the like. The term “user equipment” refers to a user mobile terminal, for example, a terminal device capable of performing wireless communication with a base station or a micro base station, including a mobile phone, a notebook computer and the like.
(112) Moreover, the embodiments of the present invention disclosed herein can be implemented on a computer program product. More particularly, the computer program product is a product as follows: a product having a computer readable medium encoded with computer program logic thereon, when being executed on a computing equipment, the computer program logic provides related operations to implement the technical solution of the prevent invention. When being executed on at least one processor of a computing system, the computer program logic enables the processor to execute the operations (methods) described in the embodiments of the present invention. Such setting of the present invention is typically provided as software, codes and/or other data structures provided or encoded on the computer readable medium, e.g., an optical medium (e.g., Compact Disc Read Only Memory (CD-ROM)), a flexible disk or a hard disk and the like, or other media such as firmware or micro codes on one or more Read Only Memory (ROM) or Random Access Memory (RAM) or Programmable Read Only Memory (PROM) chips, or a downloadable software image, a shared database and the like in one or more modules. The software or the firmware or such configuration can be installed on the computing equipment, so that one or more processors in the computing equipment execute the technical solution described in the embodiments of the present invention.
(113) In addition, each functional module or each feature of the base station device and the terminal device used in each of the above embodiments may be implemented or executed by a circuit, which is usually one or a plurality of integrated circuits. Circuits designed to execute various functions described in this description may include general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs) or general-purpose integrated circuits, field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic, or discrete hardware components, or any combination of the above. The general-purpose processor may be a microprocessor; or the processor may be an existing processor, a controller, a microcontroller, or a state machine. The above-mentioned general-purpose processor or each circuit may be configured with a digital circuit, or may be configured with a logic circuit. In addition, when an advanced technology that can replace current integrated circuits emerges due to advances in semiconductor technology, the present invention may also use integrated circuits obtained using this advanced technology.
(114) Although the present invention is already illustrated above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that, without departing from the spirit and scope of the present invention, various modifications, replacements and changes can be made to the present invention. Therefore, the present invention should not be defined by the above embodiments, but should be defined by the appended claims and equivalents thereof.