WO2020000792A1

WO2020000792A1 - Random access method, user equipment and device with storage function

Info

Publication number: WO2020000792A1
Application number: PCT/CN2018/111048
Authority: WO
Inventors: Kai Kang; Hua QIAN; Jianxin JIA; Xuming PEI; Zhenghang ZHU; Zhenyu Tang
Original assignee: Huizhou Tcl Mobile Communication Co., Ltd
Priority date: 2018-06-27
Filing date: 2018-10-19
Publication date: 2020-01-02
Also published as: CN110650486A; CN110650486B

Abstract

A random access method, an UE and a device with a storage function are disclosed. The random access method includes: in a random access procedure, the UE transmitting a request message to a base station; starting a first timer and a second timer to begin counting; performing a clear channel assessment on the current channel, if the current channel is available, the second timer continues to count, and if the current channel is unavailable, the second timer pauses, while the first timer remains in a counting state regardless of whether the current channel is available or not. A random access failure is determined, if the UE does not receive a response message transmitted by the base station when the first timer or the second timer counted to reach a preset time threshold. In the above manner, the present disclosure can improve the efficiency of random access.

Description

RANDOM ACCESS METHOD, USER EQUIPMENT AND DEVICE WITH STORAGE FUNCTION

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of communications, and in particular, to a random access method, an user equipment (UE) , and a device with a storage function.

BACKGROUND

In current radio communication technologies, the shortage of frequency bands has become increasingly serious, and the communication in an unlicensed frequency band can be adopted to broaden the available frequency bands to solve the problem. In the wireless communication system based on a long term evolution (LTE) network, license assisted access (LAA) technology is adopted to use unlicensed frequency bands with the assistance of a licensed frequency band.

With the popularity of 5G new radio (NR) networks, scenarios for enhancing unlicensed frequency band access in 5G NR systems are required. In the application scenario of the new 5G NR in unlicensed band (NR-U) , the UE needs to complete a random access in the unlicensed frequency band. In order to ensure fair communication with nodes such as Wi-Fi, Bluetooth, and LTE-U, a Listen before Talk (LBT) mechanism is introduced when the unlicensed band is used. Since the LBT cannot determine the time slot of transmission, it will affect the efficiency of random access.

SUMMARY

The technical problem to be solved by the present disclosure is to provide a random access method, an UE and a device with a storage function, to improve the efficiency of random access.

To solve the above technical problem, a technical solution adopted by the present disclosure is to provide a random access method, including an UE transmitting a request message to a base station, starting a first timer and a second timer to begin counting, performing a clear channel assessment on the current channel that, if the current channel is available, the second timer continues to count, or if the current channel is unavailable, the second timer pauses counting, and regardless of whether the current channel is available or not, the first timer maintains a counting state. A random access failure is determined if the UE does not receive the response message transmitted by the base station, when the first timer or the second timer reach a preset time threshold.

In order to solve the above technical problem, another technical solution adopted by the present disclosure is to provide an UE, including a processor, a communication circuit, and a storage, the processor connected to the communication circuit and the storage, the storage stored with program instructions, and the processor executing the program instructions, to implement the method as described above by the communication circuit.

In order to solve the above technical problem, another technical solution adopted by the present disclosure is to provide a device with a storage function, wherein program instructions are stored, and the program instructions are configured to be executed to implement the method as described above.

The invention has the beneficial effects that, different from the prior art, in the present disclosure, after the request message is transmitted to the base station, two timer is configured to count, the waiting time of the UE may be adjusted based on the communication quality of the current channel, which may quickly determine the random access failure, thus saving the waiting time of the UE, further to improve the efficiency of the random access.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic flowchart diagram of a first embodiment of a random access method provided by the present disclosure.

FIG. 2 is a schematic flowchart diagram of a second embodiment of a random access method provided by the present disclosure.

FIG. 3 is a schematic flowchart diagram of a third embodiment of a random access method provided by the present disclosure.

FIG. 4 is a schematic flowchart diagram of a fourth embodiment of a random access method provided by the present disclosure.

FIG. 5 is a schematic diagram of the structure of a UE of an embodiment provided by the present disclosure.

FIG. 6 is a schematic diagram of the structure of a device with a storage function provided by the present disclosure.

DETAILED DESCRIPTION

The technical schemes in the embodiments of the present disclosure will now be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure, and it will be apparent that the described embodiments are merely a part of the embodiments of the disclosure, instead of all embodiments. All other embodiments obtained based on the embodiments in the present disclosure by those of ordinary skill in the art without making creative work should fall into the scope of the present disclosure.

Referring to FIG. 1, FIG. 1 is a schematic flowchart diagram of a first embodiment of a random access method according to the present disclosure. As shown in FIG. 1, the random access method provided by the present disclosure includes following steps.

In step S101, the method includes an UE transmitting a request message to a base station.

The random access procedure refers to a process in which the UE discovers the downlink signal, synchronizes with the base station, decodes broadcast information of the base station, and completes a first uplink transmission. In a specific implementation scenario, the licensed frequency band cannot meet the current wireless communication requirements, and thus the UE needs to complete the random access procedure based on the NR unlicensed frequency band. The UE transmits a request message to the base station to indicate the base station of the appearance of the random access request, and allows the base station to estimate the delay and the path loss between the base station and the UE.

In this implementation scenario, the message transmitted by the UE requires a determined transmission power and a determined transmission format to be transmitted to the base station at a selected timing. In this implementation scenario, the transmission format may be determined based on broadcast system information, the transmission power being estimated based on downlink path loss in the downlink reference signal or control signal, and the timing of transmission is randomly selected. In this implementation scenario, the request message includes a first message and a third message, the first message includes a set of preamble sequences selected from the contention preamble, and the third message includes at least one of a radio resource control connection request and a plan request, as well as a cell radio network temporary identifier. To decode the preamble sequence is relatively easy, so that the base station can quickly decode the preamble after receiving the preamble, and obtain the information contained in the preamble.

In other implementation scenarios, the request message may also include only the first message or only the third message.

The accessing scenario of the NR-based unlicensed frequency band referred in the present implementation scenario includes following cases.

A scenario of a carrier aggregation between an NR cell of a licensed frequency band (primary cell) and an NR cell of an unlicensed frequency band (secondary cell) may be included, where the NR cell of an unlicensed frequency band (secondary cell) may include both uplink and downlink, or may only include the downlink.

A scenario of a dual connectivity between an LTE cell of a licensed frequency band (primary cell) and an NR cell of an unlicensed frequency band (secondary cell) may be included.

A scenario of a stand-alone NR cell of unlicensed frequency band may be included.

A scenario of an NR cell with a downlink in an unlicensed frequency band and an uplink in a licensed frequency band may be included.

A scenario of a dual connectivity between an NR cell of a licensed frequency band (primary cell) and an NR cell of an unlicensed frequency band (secondary cell) may also be included.

In this implementation scenario, both the user equipment and the base station work in an unlicensed frequency band. In other implementation scenarios, only one ofthe user equipment and the base station may operate in an unlicensed frequency band, and the other may operate in a licensed frequency band, or both of them mayoperatein the licensed frequency band. In step S102, the method includes starting a first timer and a second timer to begin counting.

In this implementation scenario, after the UE transmits the random access request, the first timer and the second timer are simultaneously started. In the unlicensed frequency band, the frame length of the LTE-based unlicensed frequency band access packet is up to 10 ms, and the IEEE 802.11a/g/n/ac packet has a frame length of approximately 6 ms. Then, in the NR-based unlicensed frequency band access, the timer-period of the first timer must be set to be larger than or equal to 10 ms.

In step S103, the method includes performing a clear channel assessment on the current channel that, if the current channel is available, the second timer continues to count, or if the current channel is unavailable, the second timer pauses counting, and regardless of whether the current channel is available or not, the first timer maintains a counting state.

In a specific implementation scenario, the UE performs a clear channel assessment (CCA) on the current channel. The principle of clear channel assessment is similar to energy detection, with a purpose of assess whether the target channel is idle. The method for clear channel assessment mainly includes detecting whether the energy exceeds a determined threshold (at least 10 dB exceeding the receiver sensitivity) , or detecting whether the channel has a signal complying with IEEE 802.11, IEEE 802.15.4, Bluetooth, or LTE-U, if a signal with an energy exceeding the determined threshold is detected, or a signal complying with IEEE 802.11, IEEE 802.15.4, Bluetooth, or LTE-U, etc., is detected, then the channel is considered to be busy, and the channel is currently unavailable. Since the clear channel assessment method is a prior art, detailed description will not be made here to avoid repetition.

After receiving the request message transmitted by the UE, if the base station successfully decodes the request message, the base station transmits a response message to the UE to notify the UE that the random access connection can be established. If the UE does not receive the response message, the possible reasons include that the base station cannot obtain the channel through the LBT to transmit the response message to the UE, orthe base station does not successfully receive the request message. In this implementation scenario, the UE performs a clear channel detection to determine whether the current channel is available, and the second timer is configured to limit the waiting time of the UE when the current channel is available. If the current channel is not available, the response message cannot be transmitted to the UE even if the base station successfully receives the request message, so the second timer is paused. If the current channel is available, the base station can transmit a response message to the UE, so the second timer continues to count.

Meanwhile, the first timer remains in acounting state regardless of whether the current channel is available or not. The first timer is configured to control the total waiting time of the UE.

In step S104, the method includes determining that the random access fails, if the UE does not receive the response message transmitted by the base station, when the first timer or the second timer reach a preset time threshold.

In this implementation scenario, when any one of the first timer and the second timer reaches its preset time threshold, if the UE does not receive the response message transmitted by the base station, it is determined that the random access fails.

When the first timer reaches its preset time threshold, it is indicated that the second timer keeps in a pause state for a long time, so it can be inferred that the reason for the random access failure may include that the base station cannot obtain the available channel through the LBT to transmit the random access response information to the UE. When the second timer reaches the preset time threshold, it is indicated that the current channel is in an available state, so it can be inferred that the reason for the random access failure may include at least one of: the insufficient transmission power, a conflict with and other users in the random access frequency band, a conflict with other radio transmission ways using the same frequency band, and a conflict between the random access response information transmitted by the base station and other terminals.

In this implementation scenario, after the UE determines that the random access fails, steps S101-S103 are repeatedly performed until the first timer and the second timer counts to reach their preset time thresholds, and the response message transmitted by the base station is received.

In order to improve the efficiency of the random access and avoid the situation that the UE repeatedly transmits the request message to the base station, every time when the step S101 is executed, the number of times for transmitting the request message is increased by one, and when the number of times for transmitting the request message reaches a preset threshold (for example, 5 times, 10 times, etc. ) , the random access method is stopped.

In this implementation scenario, the response message includes a second message and a fourth message, the second message including at least one of time adjustment information, cell radio network temporary identifier (C-RNTI) , and uplink resource allocation (e.g., an uplink grant) . The fourth message includes a contention resolution.

In other implementation scenarios, the response message may also include only the second message or only the fourth message. When the request message transmitted by the UE only includes the first message, the response message only includes the second message. When the request message transmitted by the UE only includes the third message, the response message only includes the fourth message.

According to the above description, the first timer and the second timer are started after the UE transmits a request message to the base station, and by the monitoring the communication channel state, the time for UE waiting for the response message transmitted by the base station can be flexibly controlled, and it can be quickly determined that the random access fails, so as to effectively shorten the waiting time, thereby improving the efficiency of random access. Besides, the reason why the random access failure may be roughly determined, according to whether the first timer reaches its preset time threshold or the second timer reaches its preset time threshold.

Referring to FIG. 2, FIG. 2 is a schematic flowchart of a second embodiment of a random access method according to the present disclosure. As shown in FIG. 2, the random access method of the present disclosure includes following steps.

In step S201, the method includes the UE transmitting a first message to the base station.

In step S202, the method includes starting a first timer and a second timer to begin counting.

In step S203, the method includes performing a clear channel assessment on the current channel, if the current channel is available, the second timer continues to count, and if the current channel is unavailable, the second timer pauses counting, and meanwhile, regardless of whether the current channel is available, the first timer maintains a counting state.

The steps S201-S203 are substantially the same with the steps S101-S103 of the first embodiment of the random access method provided by the present disclosure, and refers to the case that the request message in the steps S101-S103only includes the first message, and the response message only includes the third message, and detailed description will not be repeated here.

In step S204, the method includes that the first timer and the second timer stop counting, when the UE receives the second message transmitted by the base station before the first timer or the second timer become invalid as reaching the preset threshold.

In a specific implementation scenario, before the first timer and the second timer reach their preset thresholds, the UE receives the second message transmitted by the base station, and it is indicated that the unlicensed frequency band access can be requested to the base station. In order that the subsequent random access method may proceed smoothly, the first timer and the second timer stop counting. In this implementation scenario, the second message includes at least one of time adjustment information, a cell radio network temporary identifier (C-RNTI) , and an uplink resource allocation.

In step S205, the method includes the UE transmitting a third message to the base station by using the uplink resource allocation.

In this implementation scenario, the UE transmits a third message to the base station using the uplink resource allocation received in step S204. In this implementation scenario, the third message includes at least one of a radio resource control connection request and a plan request, as well as a cell radio network temporary identifier received in step S204 and temporarily allocated to the UE.

In stepS206, the method includes clearing the first timer and the second timer, and starting the first timer and the second timer to begin counting.

In this implementation scenario, in step S204, because the UE receives the response message transmitted by the base station, and counting of the first timer and the second timer are paused, the UE may clear the first timer and the second timer to restart the counting. In other implementation scenarios, the first timer and the second timer may be directly cleared in step 204, and the first timer and the second timer are directly started in this step.

In step S207, the method includes performing a clear channel assessment on the current channel, if the current channel is available, the second timer continues to count, and if the current channel is unavailable, the second timer is paused, and meanwhile the first timer remains in a counting state regardless of whether the current channel is available or not.

Since the communication quality of the random access of the unlicensed frequency band is not very stable, after transmitting the third message to the base station, the communication state of the current channel is assessed again. This step is basically similar to step S203, and details are not described herein again.

In step S208, the method includes determining that the random access fails, if the UE does not receive the fourth message transmitted by the base station, when the first timer or the second timer counts to reach their preset time thresholds.

In this implementation scenario, the base station may simultaneously receive a second message transmitted by multiple UE having the same preamble sequence, and the base station selects one UE from the multiple UEs and transmits the fourth message to the UE to notify the UE that the communication can be performed in an unlicensed frequency band. In this implementation scenario, the fourth message includes a contention resolution, such as an identifier of the selected UE or an identifier of the contention resolution. The UE can learn that random access communication can be performed in an unlicensed frequency band according to the contention resolution.

In this implementation scenario, when any one of the first timer and the second timer reaches its preset threshold, the random access failure may be determined. If the first timer reaches its preset threshold, it indicates that the second timer is in a pause state for a long time, so it can be inferred that the reason for the random access failure is that the base station cannot obtain the available channel to transmit the fourth information to the UE. If the second timer reaches its preset threshold, it indicates that the current channel is in an available state, so it can be inferred that the reason for the random access failure includes at least one of: the insufficient transmission power, a conflict with and other users in the random access frequency band, a conflict with other radio transmission ways using the same frequency band, and a conflict between the random access response information transmitted by the base station and other terminals.

In this implementation scenario, after the UE determines that the random access fails, steps S201-S207 are repeatedly performed until the first timer or the second timer counts to reach their preset thresholds, or the fourth message transmitted by the base station is received.

In order to improve the efficiency of the random access and avoid the situation that the UE repeatedly transmits the request message to the base station, every time when the step S201 is executed, the number of times for transmitting the first message is increased by one, and when the number of times for transmitting the first message reaches a preset threshold (for example, 5 times, 10 times, etc. ) , the random access method is stopped.

In another implementation scenario, before any one of the first timer and the second timer reaches its preset time threshold, the UE receives the fourth message transmitted by the base station, and it is determined that the random access succeeded.

According to the above description, in the embodiment, after the UE transmits the first message and the third message to the base station, the first timer and the second timer are started, the first timer is configured to control the total time of UE waiting for the response message transmitted by the base station based on received message, the second timer is configured to control the time of the UE waiting for the response message in a good channel state, and the waiting time can be flexibly adjusted to quickly determine the random access failure and reduce waste in waiting time, thereby improving the efficiency of random access. Besides, the reason why the random access failure is roughly determined according to whether the first timer reaches its preset time threshold or the second timer reaches its preset time threshold.

Referring to FIG. 3, FIG. 3 is a schematic flowchart of a third embodiment of a random access method according to the present disclosure. As shown in FIG. 3, the random access method of the present disclosure includes following steps.

In step S301, the method includes the UE transmitting the first message to the base station.

In a specific implementation scenario, the licensed frequency band cannot meet the current communication requirements, and the UE needs to complete the random access procedure based on the NR unlicensed frequency band. The UE transmits a first message to the base station to indicate the base station of the appearance of the random access request, and allows the base station to estimate a delay between the base station and the UE.

In this implementation scenario, the first message includes a set of preamble sequences selected from the contention preamble. The transmission format may be determined based on the broadcast system information, the transmission power is estimated based on the downlink path loss in the downlink reference signal or the control signal, and the timing of the transmission is randomly selected. In this implementation scenario, the first message requires to be transmitted to the base station with the determined transmission power and a transmission format at a selected timing.

In step S302, the method includes starting a first timer and a second timer to begin counting.

In this implementation scenario, a clear channel assessment is performed on the current channel, if the current channel is available, the second timer continues to count, or if the current channel is unavailable, the second timer pauses counting, and regardless of whether the current channel is available or not, the first timer maintains a counting state.

In step S303, the method includes the base station transmitting a second message to the UE.

In this implementation scenario, the base station transmits a second message to the UE based on the preamble sequence detected at a certain timing, the second message including at least one of time adjustment information, a cell radio network temporary identifier (C-RNTI) , and an uplink resource allocation (e.g., uplink grant) .

If the UE receives the second message transmitted by the base station before the first timer or the second timer reaches its preset threshold, the first timer and the second timer stop counting.

If the UE does not receive the second message transmitted by the base station before the first timer or the second timer counts to reach the preset threshold, then it is determined that the random access fails. In this implementation scenario, after the UE determines that the random access fails, steps S301-S302 are repeatedly executed until the second message transmitted by the base station is received before the first timer or the second timer reach their preset time thresholds.

In step S304, the method includes the UE transmitting a third message to the base station.

In this implementation scenario, the UE transmits the third message to the base station by using the uplink resource allocation. The third message includes at least one of a radio resource control connection request and a plan request, as well as a cell radio network temporary identifier in the received second message and temporarily allocated to the UE.

In stepS305, the method includes clearing the first timer and the second timer, and starting the first timer and the second timer to begin counting.

In this implementation scenario, the first timer and the second timer are cleared, and the first timer and the second timer are started to begin counting. A clear channel assessment on the current channel is performed, if the current channel is available, the second timer continues to count, and if the current channel is unavailable, the second timer is paused, and meanwhile the first timer remains in a counting state regardless of whether the current channel is available or not.

In stepS306, the method includes the base station transmitting a fourth message to the UE.

In this implementation scenario, the base station may simultaneously receive a third message transmitted by multiple UE having the same preamble sequence, and the base station selects one UE from the multiple UE and transmits the fourth message to the UE to notify the UE that the communication can be performed in an unlicensed frequency band. In this implementation scenario, the fourth message includes a contention resolution, such as an identifier of the selected UE or an identifier of the contention resolution. The UE can learn that random access communication can be performed in an unlicensed frequency band according to the contention resolution.

If the UE receives the fourth message transmitted by the base station before the first timer or the second timer reaches the preset time threshold, the random access is succeeded.

If the UE does not receive the fourth message transmitted by the base station, when the first timer or the second timer counts to reach the preset time threshold, it is determined that the random access fails. In this implementation scenario, after the UE determines that the random access fails, the steps S301-S305 are repeatedly performed until the fourth message transmitted by the base station is received before the first timer or the second timer reach their preset time thresholds.

According to the above description, in the implementation, when establishing the random access based on the unlicensed frequency band, after transmitting the first message and the second message to the base station, the first timer and the second timer are started to begin counting. The first timer is configured to control the total time of UE waiting for the response message transmitted by the base station, and the second timer is configured to control the waiting time of the UE waiting for the response message from the base station, when the channel is in a good communication state. In this way, the waiting time of the UE can be flexibly adjusted, the random access failure can be quickly determined, and the unnecessary waiting time can be solved, thereby improving the efficiency of random access. Besides, the reason why the random access failure is roughly determined according to whether the first timer reaches its preset time threshold or the second timer reaches its preset time threshold.

FIG. 4 is a schematic flowchart of a third embodiment of a random access method according to the present disclosure. As shown in FIG. 4, the random access method of the present disclosure includes following steps.

In step S401, the method includes the UE simultaneously transmitting a first message and a third message to the base station.

In this implementation scenario, the first message includes a set of preamble sequences selected from the contention preamble. The transmission format may be determined based on the broadcast system information, the transmission power is estimated based on the downlink path loss in the downlink reference signal or the control signal, and the timing of the transmission is randomly selected. In this implementation scenario, the first message requires to be transmitted to the base station with the determined transmission power and a transmission format at a selected timing. The third message includes at least one of a radio resource control connection request and a plan request, as well as a cell radio network temporary identifier temporarily allocated to the UE.

In stepS402, the method includes starting a first timer and a second timer to begin counting.

In step S403, the method includes the base station simultaneously transmits the second message and the fourth message to the UE.

In this implementation scenario, the base station transmits a second message to the UE based on the preamble sequence detected at a certain timing, the second message including at least one of time adjustment information, a cell radio network temporary identifier (C-RNTI) , and an uplink resource allocation (e.g., uplink grant) . The fourth message includes a contention resolution, such as an identifier of the selected UE or an identifier of the contention resolution. The UE can learn that random access communication can be performed in an unlicensed frequency band according to the contention resolution..

If the UE receives the second message and the fourth message transmitted by the base station before the first timer or the second timer reaches the preset time threshold, the random access is succeeded.

If the UE does not receive the second message and the fourth message transmitted by the base station, when the first timer or the second timer counts to reach the preset time threshold, it is determined that the random access fails. In this implementation scenario, after the UE determines that the random access fails, the steps S401-S402 are repeatedly performed until the fourth base station transmitted by the base station is received before the first timer or the second timer reach their preset time thresholds.

According to the above description, in the implementation, when establishing the random access based on the unlicensed frequency band, after transmitting the first message and the third message to the base station, the first timer and the second timer are started to begin counting. The first timer is configured to control the total time of UE waiting for the response message transmitted by the base station, and the second timer is configured to control the waiting time of the UE waiting for the corresponding response message from the base station, when the channel is in a good communication state. In this way, the waiting time of the UE can be flexibly adjusted, the random access failure can be quickly determined, and the unnecessary waiting time can be solved, thereby improving the efficiency of random access. Besides, the reason why the random access failure is roughly determined according to whether the first timer reaches its preset time threshold or the second timer reaches its preset time threshold.

Please refer to FIG. 5. FIG. 5 is a schematic structural diagram of an embodiment of a UE provided by the present disclosure. The UE 10 includes a processor 11, a storage12 and a communication circuit 13 which are connected with the processor 11. The storage 12 is configured to store program data, the processor is configured to operate program data in the storage 12 to control the communication circuit 13 to communicate and perform random access method as follows.

The processor 11 of the UE 10 transmits a request message to the base station through the communication circuit 13. The processor 11 starts the first timer and the second timer to begin counting. The processor 11 performs a clear channel assessment on the current channel through the communication circuit 13, and if the current channel is available, the processor 11 controls the second timer to continue counting, and if the current channel is unavailable, the processor 11 controls the second timer to pause counting. Meanwhile, the processor 11 controls the first timer to remain in a counting state regardless of whether the current channel is available or not. If the UE 10 does not receive the response message transmitted by the base station through the communication circuit 13 when the first timer or the second timer counts to reach the preset time threshold, the processor 11 determines that the random access fails.

Before any one of the first timer and the second timer reaches the preset time threshold, the UE 10 receives the response message transmitted by the base station through the communication circuit 13, and then it is determined that the random access is succeeded.

Herein, the specific process of the processor 11 for implementing the above functions may be referred to the above method embodiments.

According to the above description, the UE in this embodiment may transmit a request message to the base station, and start the first timer and the second timer to begin counting. The first timer is configured to control the total time of UE waiting for the response message transmitted by the base station, and the second timer is configured to control the waiting time of the UE waiting for the response message from the base station, when the channel is in a good communication state. In this way, the waiting time of the UE can be flexibly adjusted, the random access failure can be quickly determined, and the unnecessary waiting time can be solved, thereby improving the efficiency of random access. Besides, the reason why the random access failure is roughly determined according to whether the first timer reaches its preset time threshold or the second timer reaches its preset time threshold.

Please refer to FIG. 6. FIG. 6is a schematic structural diagram of an embodiment of a device with a storage function provided by the present disclosure. The device 20 with the storage function stores at least one program instruction 21 configured to execute the random access method as shown in FIG. 1-FIG. 4. In one embodiment, the device with the storage function may be a storage chip in a terminal, a hard disk, a removable hard disk, or be other readable, writeable, and storable device such as a USB flash drive and an optical disk, and may also be a server or the like.

As described above, in this embodiment, the program or the instruction stored in the device with the storage function in this embodiment may be configured to flexibly adjust the waiting time of the UE, and to quickly determine the random access failure and solve the unnecessary waiting time, thereby improving the efficiency of random access. Besides, the reason why the random access failure is roughly determined according to whether the first timer reaches its preset time threshold or the second timer reaches its preset time threshold.

Different from the prior art that only one conventional timer is used to control the waiting time of the user waiting for a response message from the base station, the present disclosure starts the first timer and the second timer after the UE transmits a request message to the base station. The first timer is configured to control the total time of UE waiting for the response message transmitted by the base station based on received message, the second timer is configured to control the time of the UE waiting for the response message in a good channel state, and the waiting time can be flexibly adjusted to quickly determine the random access failure and reduce waste in waiting time, thereby improving the efficiency of random access. Besides, the reason why the random access failure is roughly determined according to whether the first timer reaches its preset time threshold or the second timer reaches its preset time threshold.

The above description merely illustrates some exemplary embodiments of the disclosure, which however are not intended to limit the scope of the disclosure to these specific embodiments. Any equivalent structural or flow modifications or transformations made to the disclosure, or any direct or indirect applications of the disclosure on any other related fields, shall all fall in the scope of the disclosure.

Claims

A random access method, comprising:

transmitting a request message to a base station by a UE;

starting a first timer and a second timer to begin counting;

performing a clear channel assessment on a current channel that, when the current channel is available, the second timer continues to count, and when the current channel is unavailable, the second timer pauses counting, and the first timer remains in counting state, regardless of whether the current channel is available or not;

determining that the random access fails, when the UE does not receive a response message transmitted by the base station when at least one of the first timer and the second timer are timed to reach a preset time threshold.
The method according to claim 1, wherein after the determining that the random access fails, the method further comprises:

repeating the step of transmitting the request message to the base station and subsequent steps.
The method of claim 2, wherein

every time when the step of transmitting the request message to the base station is executed, the number of times for transmitting the request message is increased by one, and when the number of times for transmitting the request message reaches a preset threshold, the random access procedure is stopped.
The method of claim 1 wherein

The request message comprises a first message, where the first message including a preamble sequence;

The transmitting the request message to the base station comprising:

transmitting the first message to the base station in a determined transmission power and a determined transmission format at a selected timing.
The method of claim 4, wherein

the preamble sequence is a set of preamble sequences selected from contention preambles.
The method of claim 4 wherein

the transmission format is determined based on broadcasted system information.
The method of claim 4 wherein

the transmission power is estimated based on a downlink path loss in a downlink reference signal or a control signal.
The method of claim 4, wherein

the timing is randomly selected.
The method of claim 1, wherein

the response message comprises a second message, the second message comprising at least one of time adjustment information, a cell radio network temporary identifier, and an uplink resource allocation.
The method of claim 1, wherein

the request message comprises a third message, the third message comprising at least one of a radio resource control connection request and a plan request, as well as the cell radio network temporary identifier;

before the transmitting the request message to the base station, the method comprising:

receiving the second message transmitted by the base station; and

the transmitting the request message to the base station comprising:

transmitting the third message to the base station in response to the second message.
The method of claim 1, wherein

the response message comprises a fourth message, the fourth message comprising a contention resolution.
The method of claim 1, wherein

the request message comprises the first message and the third message,

transmitting the request message to the base station comprising:

transmitting the first message and the third message to the base station.
The method of claim 12 wherein

the response message comprises the second message and the fourth message.
The method of claim 1, wherein the method further comprises:

determining that the random access is succeeded, when the UE receives the response message transmitted by the base station before at least one of the first timer and the second timer reaches the preset time threshold.
The method according to any one of claims 1 to 14, wherein the UE and the base station operate in an unlicensed frequency band.
A UE, comprising: a processor, a communication circuit and a storage, the processor connected to the communication circuit and the storage, the storage stored with program instructions, and the processor executing the program instructions, to implement the method in any one of claims 1-15 with the communication circuit.
A device with a storage function, wherein program instructions are stored, and the program instructions are configured to be executed to implement the method of any one of claims 1-15.