WO2017166023A1

WO2017166023A1 - Random access method and apparatus

Info

Publication number: WO2017166023A1
Application number: PCT/CN2016/077514
Authority: WO
Inventors: 于峰; 于映辉
Original assignee: 华为技术有限公司
Priority date: 2016-03-28
Filing date: 2016-03-28
Publication date: 2017-10-05
Also published as: CN108353435A

Abstract

Provided are a random access method and apparatus. The method comprises: a network device receives, from a terminal device, a random access request message; and the network device transmits, to the terminal device, at least two random access response (RAR) messages within a set time period, the RAR message being used to enable the terminal device to perform random access, wherein the set time period is a period from the reception of the random access request message to the transmission of the message 4 by the network device. The method and apparatus are used to solve a problem in the prior art in which random access of a terminal device requires high power consumption and reduces a RACH capacity.

Description

Method and device for random access

Technical field

The present invention relates to the field of communications technologies, and in particular, to a method and apparatus for random access.

Background technique

In the Machine-to-Machine (M2M) system, the terminal equipment also needs a random access procedure to establish a connection and complete uplink synchronization. The random access procedure in the M2M system has some message changes and streamlining of the process compared to the Long Term Evolution (LTE) random access procedure. Take the contention-based random access process as an example:

Message 1 in the M2M system includes Buffer Status Reports (BSR) information. Message 2 includes random access RNTI (RA-RNTI) and random number, and allocates cell radio network temporary identifier (Cell RNTI). , C-RNTI), the transmission resource of the message 3 is simultaneously allocated, the data can be directly transmitted in the message 3, and the message 4 is a conflict resolution.

The reliability of the physical physical layer downlink control channel (PDCCH) channel of the M2M is only 90%, which is different from 99% of LTE, and the RAR message is not retransmitted. This leads to the terminal equipment receiving many times. The transmission failure is not caused by the RAR message, and the cause of this problem is mainly because the channel quality is not good.

When the terminal device sends the message 1, if the message 2 is not received, the random access will be re-initiated. Since the reliability of the physical layer physical downlink control channel (PDCCH) is only 90%, even if the network device allows the terminal device to access, the message 2 response is sent to the terminal device, and the message 2 fails to be transmitted due to poor channel quality. The probability is relatively high, so that a large number of terminal devices cannot successfully receive the message 2, and the random access is re-initiated, resulting in an increase in power consumption of the terminal device and a reduction in the random access channel (RACH) capacity. .

Summary of the invention

A method and apparatus for random access are described herein to solve the problem that the terminal device of the random access scheme in the prior art has large power consumption and reduces the RACH capacity.

In a first aspect, a method for random access is provided, including:

Receiving, by the network device, a random access request message of the terminal device;

The network device sends at least two random access response RAR messages to the terminal device in a set time period, where the RAR message is used for random access by the terminal device, where the set time period is The time between the random access request message and the sending of the message 4 by the network device.

In a possible design, sending at least two RAR messages to the terminal device within a set time period includes:

Sending the RAR message at least twice consecutively before receiving the message 3; or

After receiving the random access request message of the terminal device, the RAR message is sent for the first time. If the message 3 sent by the terminal device is not received at the set resource location, the RAR message is sent a second time.

In this design, transmitting the RAR message multiple times can increase the probability that the terminal device receives the RAR message, thereby reducing the transmission failure caused by the poor channel quality.

In one possible design, the set resource location includes:

The first receives the resource location of message 3; or the retransmission location of message 3.

In one possible design, the transmitting the at least two RAR messages within the set time period comprises: transmitting the at least two RAR messages on the downlink control channel within a set time period.

In a possible design, the method further includes adding a cell radio network temporary identifier C-RNTI to the at least two RAR messages that are sent, where the C-RNTI is used by the terminal device to receive the RAR message. When the random access fails and the random access is initiated again, the random access procedure is initiated according to the C-RNTI.

In this design, the C-RNTI is carried when the RAR message is sent, so that the RAR is received. The terminal device of the message can perform the second random access procedure according to the C-RNTI in the RAR message when the first random access fails, thereby reducing the probability that the message 1 is identical when re-accessing, and can also achieve the reduction. The probability of collision of message 3.

In a possible design, the addition of the cell radio network temporary identifier C-RNTI in the at least two RAR messages is different.

In a second aspect, a method for random access is provided, including:

After receiving the random access request message of the terminal device, the network device adds a C-RNTI to the RAR message sent to the terminal device;

The network device sends the RAR message to the terminal device; the terminal device fails to access the random access, and when the random access is initiated again, the random access procedure is initiated by using the C-RNTI carried in the received RAR message.

In a third aspect, a method for random access is provided, including:

The terminal device sends a random access request message to the network device by using a random number;

The terminal device detects at least two RAR messages sent by the network device in a set time period;

Random access is performed according to any RAR message received.

In a possible design, the detecting, by the terminal device, the at least two RAR messages sent by the network device in the set time period includes:

Detecting whether there are at least two RAR messages continuously transmitted by the network device during the set time period.

Detecting whether there is a first RAR message sent by the network device in the first time period;

If the first RAR message is received, after sending the message 3 corresponding to the first RAR message, it is detected whether there is a message 4 sent by the network device, if there is no message 4, In the second time period, it is detected whether there is a second RAR message sent by the network device.

In a possible design, when the terminal device fails to access random access, the method further includes:

Determining a target RAR message from the at least two RAR messages;

Obtaining a C-RNTI from the target RAR message, and re-initiating a random access procedure by using the C-RNTI.

In one possible design, determining the target RAR message from the at least two RAR messages includes:

Obtaining at least two corresponding C-RNTIs from the at least two RAR messages;

If the at least two C-RNTIs are different, determining, by the terminal device, the RAR message received by the terminal device in the at least two RAR messages as the target RAR message.

In this design, selecting one of the plurality of C-RNTIs to receive the C-RNTI and re-performing the random access procedure can ensure the validity of the random number used for random access again.

In a fourth aspect, a method for random access is provided, including:

After the terminal device initiates the random access request message by using the random number, receiving the RAR message sent by the network device;

When the random access of the terminal device fails, the C-RNTI is obtained from the RAR message, and the random access procedure is re-initiated by using the obtained C-RNTI.

In a fifth aspect, an embodiment of the present invention provides a network device, where the network device has a function of implementing network device behavior in the foregoing method design. The functions may be implemented by hardware or by corresponding software implemented by hardware. The hardware or software includes one or more modules corresponding to the functions described above. The modules can be software and/or hardware.

In a possible design, the structure of the network device includes a receiving module and:

The receiving module is configured to receive a random access request message of the terminal device;

The sending module is configured to send at least two random access response RAR messages to the terminal device in a set time period, where the RAR message is used for random access by the terminal device; The time period is the time between when the network device receives the random access request message and when the message 4 is sent.

In a possible design, the sending module is specifically configured to continuously send the RAR message twice before the receiving module receives the message 3; or, after receiving the random access request message of the terminal device, The RAR message is sent for the first time. If the message 3 sent by the terminal device is not received at the set resource location, the RAR message is sent a second time.

In one possible design, the set resource location includes:

With reference to the fifth aspect, or the first to the second possible implementation manners of the fifth aspect, in a third possible implementation manner, the sending module is specifically configured to be in a set time period and in a downlink control channel Send at least two RAR messages on.

In a possible design, the network device further includes:

a processing module, configured to add a cell radio network temporary identifier C-RNTI to the at least two RAR messages that are sent, where the C-RNTI is used to perform random access failure and re-initiation when the UE uses the received RAR message During random access, a random access procedure is initiated according to the C-RNTI.

In one possible design, the processing mode is further configured to add different C-RNTIs in the at least two RAR messages.

In a sixth aspect, another network device is provided, where the network device includes:

a receiving module, configured to receive a random access request message of the terminal device;

a processing module, configured to add a C-RNTI to the RAR message sent to the terminal device, where the C-RNTI is used to initiate random access by using the C-RNTI when the terminal device initiates random access for the second time Entry process

And a sending module, configured to send the RAR message to the terminal device.

A seventh aspect provides a terminal device, including:

a sending module, configured to send a random access request message to the network device by using a random number;

And a processing module, configured to detect at least two RAR messages sent by the network device within a set time period; and perform random access according to any RAR message received.

In a possible design, the processing module is specifically configured to detect whether there are at least two RAR messages continuously sent by the network device during the set time period.

In a possible design, the processing module is specifically configured to detect whether there is a first RAR message sent by the network device in the first time period;

The terminal device further includes a receiving module, configured to receive the first RAR message;

The sending module is configured to send, after receiving the first RAR message, the message 3 corresponding to the first RAR message to the network device;

The processing module is specifically configured to detect whether there is a message 4 sent by the network device, and if there is no message 4, detect whether there is a second RAR message sent by the network device in the second time period.

In a possible design, the processing module is further configured to: when the terminal device fails to access random access, determine a target RAR message from the at least two RAR messages; acquire a C-RNTI from the target RAR message, and Re-initiating the random access procedure with the C-RNTI.

In a possible design, the processing module is specifically configured to obtain corresponding at least two C-RNTIs from the at least two RAR messages; if the at least two C-RNTIs are not the same, the at least the The RAR message received by the terminal device in the two RAR messages at the latest is determined as the target RAR message.

In an eighth aspect, a terminal device is provided, where the terminal device includes:

An access module, configured to receive a RAR message sent by the network device; when the terminal device is randomly connected When the random access is initiated, the C-RNTI is obtained from the RAR message, and the random access procedure is re-initiated by using the obtained C-RNTI.

According to a ninth aspect, an embodiment of the present invention provides an M2M system, where the system includes the network device and the terminal device in the foregoing aspect.

One or both of the above technical solutions have at least the following technical effects:

Through the method provided by the foregoing embodiment, the network device can continuously send the RAR message twice to improve the success rate of the message 2. The probability that the terminal device fails to receive the RAR message due to the channel quality is reduced. Thereby, the purpose of reducing resource consumption and power consumption of random access is achieved.

DRAWINGS

FIG. 1 is a schematic flowchart of a method for random access according to Embodiment 1 of the present invention;

FIG. 2 is a schematic flowchart diagram of another method for random access according to Embodiment 2 of the present invention;

FIG. 3 is a schematic flowchart diagram of another method for random access according to Embodiment 3 of the present invention;

4 is a schematic flowchart of another method for random access according to Embodiment 4 of the present invention;

FIG. 5 is a schematic flowchart of a method for providing a method for providing a method according to Embodiment 5 of the present invention;

FIG. 6 is a schematic flowchart of a method for providing a method for providing a method according to Embodiment 6 of the present invention;

FIG. 7 is a schematic structural diagram of a network device according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of a terminal device according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is apparent that the described embodiments are a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The implementation idea of the present invention is: in the M2M system, when the terminal device initiates or re-initiates random access, two or more terminal devices may send the same random number on the same time-frequency resource, such that multiple terminals The device does not resolve the conflict in message 2. All terminal devices consider that the uplink allocation resource of message 2 is for itself and sends message 3 on it, because message 3 contains the unique identifier of each terminal device, and message 3 There is a high probability of conflict, and all terminal devices that have not been resolved by conflict must re-initiate random access. The conflict of the message 3 is more resource-consuming than the conflict of the message 1 (the different terminal devices send different random numbers on the same time-frequency resource, and the conflict is solved by the message 2), and the power consumption is greater because the message 3 And message 4 are both HARQ mechanisms.

In order to reduce the resource consumption and power consumption of the random access, in the solution provided by the embodiment of the present invention, the conflict of the message 3 may occur, and the conflict in the message 1 is adjusted as much as possible, so that the message 1 can be implemented by using the message 2. Conflict resolution.

The network device involved in the embodiments of the present invention may be a base station, or an access point, or may refer to a device in the access network that communicates with the wireless terminal through one or more sectors on the air interface. The base station can be used to convert the received air frame to the IP packet as a router between the wireless terminal and the rest of the access network, wherein the remainder of the access network can include an Internet Protocol (IP) network. The base station can also coordinate attribute management of the air interface. For example, the base station may be a Base Transceiver Station (BTS) in GSM or CDMA, or may be a base station (NodeB) in WCDMA, or may be an evolved base station (eNB or e-NodeB, evolutional Node B) in LTE. This application is not limited.

The terminal device according to the embodiment of the present invention may provide voice and/or data connectivity to the user. Sexual devices, handheld devices with wireless connectivity, or other processing devices connected to a wireless modem. The wireless terminal can communicate with one or more core networks via a Radio Access Network (RAN), which can be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal. For example, it may be a portable, pocket, handheld, computer built-in or in-vehicle mobile device that exchanges language and/or data with a wireless access network. For example, Personal Communication Service (PCS) phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDAs), etc. . A wireless terminal may also be called a system, a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, an access point, or an access point. Remote Terminal, Access Terminal, User Terminal, User Agent, User Device, or User Equipment.

The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

Embodiment 1

As shown in FIG. 1 , an embodiment of the present invention provides a method for random access, which is based on an implementation process of a network device side.

Step 101: The network device receives a random access request message of the terminal device.

Step 102: The network device sends at least two random access response RAR messages to the terminal device in a set time period, where the RAR message is used for random access by the terminal device, where the setting The time period is the time between when the network device receives the random access request message and when the message 4 is sent.

In this embodiment, the manner in which the network device sends the RAR message at least twice in the set time period includes multiple types. The following two optimization implementations are provided:

Mode 1, sending the RAR message at least twice before receiving the message 3;

The network device may send the RAR message in a set time period and send at least two RAR messages on the downlink control channel. Specifically, the RAR message may be sent on the two consecutive PDCCH channels after receiving the RA Request message by the terminal device or on multiple PDCCH channels in a period of time.

In the second mode, the RAR message is sent for the first time after receiving the random access request message of the terminal device. If the message 3 sent by the terminal device is not received at the set resource location, the RAR message is sent a second time.

In the mode 2, when the terminal device determines whether the message 3 is successfully received, it is required to determine whether the terminal device sends the message 3 (Msg3) by using the HARQ mechanism, and the maximum number of HARQs in the HARQ mechanism, and the resource location set according to the above two conditions may be :

When the resource location of the first received message 3 does not receive the message 3, it is determined that the message 3 is not successfully received, and the corresponding resource location is the resource location of the first received message 3;

When the message 3 is confiscated on the retransmission location of the message 3, it is determined that the message 3 is not successfully received, and the corresponding resource location is the retransmission location of the message 3.

Through the method provided by the foregoing embodiment, the network device continuously sends the RAR message twice to improve the success rate of the message 2. The probability that the terminal device fails to receive the RAR message due to the channel quality is reduced.

Further, because the retransmission occurs in the RACH process in the solution provided by the prior art, the terminal device retransmits according to the random number, and does not consider avoiding the collision problem with the same random number of resources. The present invention provides a method, and further includes:

Adding a cell radio network temporary identifier C-RNTI to the at least two RAR messages that are sent, where the C-RNTI is used when the terminal device fails to initiate random access by receiving the RAR message, and then initiates random access again. A random access procedure is initiated according to the C-RNTI.

The network device adds the C-RNTI when the RAR message is sent, so that after the terminal device successfully receives the message 2, if the subsequent random access request needs to be re-initiated, the C-RNTI allocated in the message 2 is used to re-initiate the random connection. The incoming request reduces the probability that message 1 is identical when re-accessing, thereby reducing the probability of collision of message 3.

In this embodiment, because the network device sends multiple messages 2, in order to improve the C-RNTI timeliness in the message 2 sent each time, the network device may add a cell radio network temporary identifier in the at least two RAR messages. C-RNTI is not the same.

The C-RNTI is obtained by the network device based on the existing allocation algorithm. The specific acquisition mode of the C-RNTI is not described here.

Embodiment 2

As shown in FIG. 2, the embodiment of the present invention further provides another method for random access, which is based on an implementation process of a network device side, and the method specifically includes:

Step 201: After receiving the random access request message of the terminal device, the network device adds a C-RNTI to the RAR message sent to the terminal device.

If the network device transmits a plurality of RAR messages to the terminal device, the C-RNTI is added to the RAR message in the manner of the foregoing embodiment.

Step 202: Send the RAR message to the terminal device; enable the terminal device to randomly access the random access, and initiate a random access procedure by using the C-RNTI carried in the received RAR message when the random access is initiated again.

Embodiment 3

As shown in FIG. 3, the embodiment of the present invention further provides another method for random access, which is based on an implementation process of the terminal device side, and the method specifically includes:

Step 301: The terminal device sends a random access request message to the network device by using a random number.

Step 302: The terminal device detects at least two RAR messages sent by the network device in a set time period, and performs random access according to any RAR message received.

Based on the foregoing description of the network device side, it can be seen that the network device side can implement the sending of the message 2 in multiple manners. Therefore, the corresponding terminal device side detects the RAR message. The specific implementation may be:

Mode 1, the network device sends the RAR message twice before the message 3, and the corresponding:

The terminal device detects whether there are at least two RAR messages continuously sent by the network device during the set time period. The set time period is a certain time period after the random access request message is sent; the time period may be a time before the random access request message is sent to the resource location of the sent message 3 that the network device of the budget may allocate.

Mode 2, the network device sends a RAR message before and after the message 3, and the corresponding:

If the first RAR message is received, after sending the message 3 corresponding to the first RAR message, it is detected whether there is a message 4 sent by the network device, and if the message 4 is not, the second time period is It is detected internally whether there is a second RAR message sent by the network device.

Further, if the network device adds the C-RNTI when the RAR message is sent, the terminal device may re-initiate the random access request after the message 2 is successfully received, and may use the C-RNTI allocated in the message 2 to re A random access request is initiated to reduce the probability that message 1 is identical when re-accessing, thereby reducing the collision probability of message 3. The specific implementation can be:

When the random access of the UE fails, and the random access is initiated again, the specific implementation includes:

A1. Determine a target RAR message from the at least two RAR messages.

The specific implementation of determining the target RAR message may be:

Acquiring at least two C-RNTIs from the at least two RAR messages; if the at least two C-RNTIs are not the same, receiving, by the terminal device in the at least two RAR messages, the latest The RAR message is determined to be the target RAR message.

A2: Obtain a C-RNTI from the target RAR message, and re-initiate a random access procedure by using the C-RNTI.

Optionally, the terminal device uses the C-RNTI in the RAR message to initiate the random access again. The specific implementation may be:

The terminal device receives the first RAR message at the first time, and receives the second RAR message at the second time, and the first RAR message carries the first C-RNTI; the second RAR message carries the first The second C-RNTI; in the case that the second time is later than the first time, when the terminal device re-initiates the random access, the second C-RNTI is used to re-initiate the random access procedure.

Embodiment 4

As shown in FIG. 4, the embodiment of the present invention further provides another method for random access, where the method specifically includes:

Step 401: After the terminal device initiates a random access request message by using a random number, the terminal device receives the RAR message sent by the network device.

Step 402: When the terminal device fails to access the random access and initiates the random access again, the C-RNTI is obtained from the RAR message, and the random access procedure is re-initiated by using the obtained C-RNTI.

In this embodiment, the terminal device may receive multiple RAR messages sent by the network device, and the C-RNTI in each RAR message that may be received is different, and the terminal device re-initiates the C-RNTI selection. The specific selection manner is the same as that in the previous embodiment, and is not described here.

Embodiment 5

As shown in FIG. 5, in order to explain the solution provided by the embodiment of the present invention in detail, the method of the embodiment of the present invention is further described by the information exchange between the terminal device side and the network device side. In this example, the network device is set. RAR messages are sent twice in a fixed time window to increase the success rate of RAR transmission. The specific implementation is:

1) The terminal device listens to the broadcast message of the system, acquires the RACH channel configuration information, and selects the corresponding RACH resource according to the information such as the coverage level of the terminal device;

2) the terminal device initiates a random access request message by using a random number;

After receiving the random access request message sent by the terminal device, the network device continuously sends two RAR messages, including the allocation of the C-RNTI and the scheduling information of the message 3, in a time window. The two RAR messages are sent before the network device allocates the resource location scheduled by the message 3;

4) The terminal device attempts to receive the RAR message within a certain period of time. If a RAR message is received, the terminal device stops receiving the RAR message, and sends the Msg3 according to the scheduling information in the received RAR message. If the RAR message is not received, the terminal device re-receives the RAR message. Random access is initiated with a random number.

5) The terminal device sends Msg3 and waits for Msg4. Msg3 can retransmit Msg3 multiple times according to the HARQ mechanism, that is, when Msg4 is not received; the terminal device can also send Msg3 without using the HARQ mechanism.

6) After receiving the Msg3 of the terminal device, the network device sends a conflict resolution message Msg4.

7) If the terminal device does not receive the Msg4, it needs to re-initiate the random access procedure, and re-initiate the random access procedure by using the C-RNTI allocated in the message 2.

Embodiment 6

As shown in FIG. 6 , in this example, the network device sends a RAR message twice before and after the message 3 to increase the success rate of the RAR. The specific implementation is as follows:

1) The terminal device listens to the broadcast message of the system, acquires the RACH channel configuration information, and selects the corresponding RACH resource according to the information such as the coverage level of the device:

3) After receiving the random access request message sent by the terminal device, the network device continuously sends the first RAR message in a time window, where the network device includes the allocation of the C-RNTI and the scheduling information for the message 3.

4) The terminal device attempts to receive the RAR message within a period of time. If a RAR message is received, the Msg3 is sent according to the scheduling information in the received RAR message; if the RAR message is not received, the random access is initiated again by using the random number. .

5) If the network device does not receive the Msg3 of the terminal device in the scheduled Msg3 resource location (or does not receive the Msg3 in the subsequent HARQ location), then the transmission of the message 2 is considered to be unsuccessful, and the network device resends the Msg2 and re-sends Allocate uplink resources and C-RNTI.

6) The terminal device sends Msg3 and waits for Msg4 or the second Msg2. If the Msg4 is not received but the second Msg2 is received, the Msg3 is resent according to the scheduling information of the second Msg2. If none of them are received, then A C-RNTI in Msg2 re-initiates random access.

7) After the terminal device sends the Msg3 according to the second Msg2, if the Msg4 is not received, the random access is re-initiated by the C-RNTI of the second Msg2.

Example 7

As shown in FIG. 7 , a network device is provided for performing the foregoing method corresponding to the network device of FIG. 1 and FIG. 5 and FIG. 6 , where the network device may include a receiving module 701 and Sending module 702:

The receiving module 701 is configured to receive a random access request message of the terminal device.

The sending module 702 is configured to send at least two random access response RAR messages to the terminal device in a set time period, where the RAR message is used for random access by the terminal device, where the set time is The segment is a time between the receiving module receiving the random access request message and sending the message 4.

Optionally, the sending module 702 is specifically configured to send the RAR message twice before the receiving module receives the message to 3; or, for sending the first time after receiving the random access request message of the terminal device. The RAR message sends the RAR message a second time if the message 3 sent by the terminal device is not received at the set resource location.

Optionally, the sending, by the sending module 702, the set resource location of the message 3 sent by the terminal device includes:

Optionally, the sending module 702 is specifically configured to send at least two RAR messages on the downlink control channel within a set time period.

Optionally, the network device further includes:

Optionally, the processing mode is further configured to add different C-RNTIs in the at least two RAR messages.

This embodiment is the same as that of the first embodiment. Therefore, the effect of the embodiment is the same as that of the first embodiment, and details are not described herein again.

For a functional architecture of the network device in the embodiment, in actual application, the network device may be a base station, and the base station has a function of implementing the behavior of the base station in the method of Embodiment 1. The functions may be implemented by hardware or by corresponding software implemented by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In one possible design, the structure of the base station includes a processor and a transmitter configured to support the base station to perform the corresponding functions in the above methods. The transmitter is configured to support communication between the base station and the UE, and send information or instructions involved in the foregoing method to the UE. The base station also A memory can be included for coupling with the processor that holds the necessary program instructions and data for the base station.

Example eight

An embodiment of the present invention further provides another network device, where the network device includes:

Example nine

As shown in FIG. 8 , an embodiment of the present invention provides a terminal device, where the terminal device is configured to perform the method corresponding to the terminal device in FIG. 3 and FIG. 5 and FIG.

The sending module 801 is configured to send a random access request message to the network device by using a random number;

The processing module 802 is configured to detect at least two RAR messages sent by the network device within a set time period; and perform random access according to any RAR message received.

Optionally, the manner in which the RAR message is sent by the network device is different, so the detection mode used by the processing module 802 to detect the RAR message is different, so the processing module 802 detects at least two sent by the network device in the set time period. The specific implementation of the RAR message can be:

In a first mode, the processing module 802 is configured to detect whether there are at least two RAR messages continuously sent by the network device in the set time period;

Manner 2: In this manner, the second RAR message is detected according to whether the first RAR message sent by the network device is detected in the first time period. The specific implementation may be:

The terminal device further includes a receiving module, where the receiving module is configured to receive the first RAR message;

The sending module 801 is configured to: after receiving, by the receiving module, the first RAR message, to the network device Sending a message 3 corresponding to the first RAR message;

The processing module 802 is specifically configured to detect whether there is a message 4 sent by the network device. If the message 4 is not available, it is detected whether there is a second RAR message sent by the network device in the second time period.

Optionally, the processing module 802 is further configured to: when the terminal device fails to access, determine a target RAR message from the at least two RAR messages; obtain a C-RNTI from the target RAR message, and use The C-RNTI re-initiates a random access procedure.

Optionally, the processing module 802 is specifically configured to obtain, from the at least two RAR messages, corresponding at least two C-RNTIs; if the at least two C-RNTIs are not the same, the at least two The RAR message received by the terminal device at the latest in the RAR message is determined as the target RAR message.

The embodiment is the same as that of the third embodiment, so the effect of the embodiment is the same as that of the third embodiment, and details are not described herein again.

Example ten

An embodiment of the present invention further provides a terminal device for implementing the method shown in Figure 4, including:

An access module, configured to receive a RAR message sent by the network device; when the terminal device fails to access the random access and initiates the random access again, obtain the C-RNTI from the RAR message, and use the acquired C-RNTI Re-initiate the random access procedure.

Based on the network device and the terminal device provided in the above-mentioned Embodiments 7 to 10, the embodiment of the present invention further provides an M2M system. In actual implementation, the network device and the ninth embodiment shown in Embodiment 7 are provided. The illustrated terminal device is a different device that implements the same solution. Therefore, when the M2M system provided by the embodiment of the present invention is used to implement the specific method, the network device shown in the seventh embodiment is used in conjunction with the terminal device shown in the ninth embodiment. The same applies to the eighth embodiment and the tenth embodiment.

The above one or more technical solutions in the embodiments of the present application have at least the following technical effects:

Through the method provided by the foregoing embodiment, the network device can continuously send the RAR message twice, High message 2 success rate. The probability that the terminal device fails to receive the RAR message due to the channel quality is reduced.

The network device adds the C-RNTI when the RAR message is sent, so that after the terminal device successfully receives the message 2, if the subsequent random access request needs to be re-initiated, the C-RNTI allocated in the message 2 is used to re-initiate the random connection. The incoming request reduces the probability that message 1 is identical when re-accessing, thereby reducing the probability of collision of message 3. Thereby, the purpose of reducing resource consumption and power consumption of random access is achieved.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

A random access method, comprising:

Receiving, by the network device, a random access request message of the terminal device;

The network device sends at least two random access response RAR messages to the terminal device in a set time period, where the RAR message is used for random access by the terminal device, where the set time period is The time between the random access request message and the sending of the message 4 by the network device.
The method of claim 1, wherein transmitting the at least two RAR messages to the terminal device within a set time period comprises:

Sending the RAR message at least twice consecutively before receiving the message 3; or

After receiving the random access request message of the terminal device, the RAR message is sent for the first time. If the message 3 sent by the terminal device is not received at the set resource location, the RAR message is sent a second time.
The method of claim 2 wherein said set resource location comprises:

The first receives the resource location of message 3; or the retransmission location of message 3.
The method according to any one of claims 1 to 3, wherein the transmitting the at least two RAR messages within the set time period comprises: transmitting at least two on the downlink control channel within a set time period Secondary RAR message.
The method according to any one of claims 1 to 4, further comprising adding a cell radio network temporary identifier C-RNTI to the at least two RAR messages that are sent, the C-RNTI being used for When the terminal device fails to initiate random access by receiving the RAR message and initiates random access again, the terminal device initiates a random access procedure according to the C-RNTI.
The method according to claim 5, wherein the adding the cell radio network temporary identifier C-RNTI in the at least two RAR messages is different.
A random access method, comprising:

The terminal device sends a random access request message to the network device by using a random number;

The terminal device detects at least two RAR messages sent by the network device in a set time period; performs random access according to any RAR message received.
The method according to claim 7, wherein the detecting, by the terminal device, the at least two RAR messages sent by the network device in the set time period comprises:

The terminal device detects, during the set time period, whether there are at least two RAR messages continuously sent by the network device.
The method according to claim 7, wherein the detecting, by the terminal device, the at least two RAR messages sent by the network device in the set time period comprises:

The terminal device detects whether there is a first RAR message sent by the network device in the first time period;

If the first RAR message is received, the terminal device detects whether there is a message 4 sent by the network device after sending the message 3 corresponding to the first RAR message, and if there is no message 4, During the second time period, it is detected whether there is a second RAR message sent by the network device.
The method according to any one of claims 7 to 9, wherein the method further comprises:

Determining a target RAR message from the at least two RAR messages after the terminal device fails to access the random access;

Obtaining a C-RNTI from the determined target RAR message, and re-initiating a random access procedure by using the C-RNTI.
The method of claim 10, wherein determining the target RAR message from the at least two RAR messages comprises:

Obtaining at least two corresponding C-RNTIs from the at least two RAR messages;

If the at least two C-RNTIs are different, determining, by the terminal device, the RAR message received by the terminal device in the at least two RAR messages as the target RAR message.
A network device, comprising: a receiving module and a sending module:

The receiving module is configured to receive a random access request message of the terminal device;

The sending module is configured to send at least two random access response RAR messages to the terminal device in a set time period, where the RAR message is used for random access by the terminal device; The time period is the time between the receiving module receiving the random access request message and sending the message 4.
The network device according to claim 12, wherein the sending module is specifically configured to continuously send the RAR message twice before the receiving module receives the message 3; or for receiving the terminal device The RAR message is sent for the first time after the random access request message, and if the message 3 sent by the terminal device is not received at the set resource location, the RAR message is sent a second time.
The network device according to claim 13, wherein the set resource location comprises:

The first receives the resource location of message 3; or the retransmission location of message 3.
The network device according to any one of claims 12 to 14, wherein the sending module is configured to send at least two RAR messages on the downlink control channel within a set time period.
The network device according to any one of claims 12 to 15, wherein the network device further comprises:

a processing module, configured to add a cell radio network temporary identifier C-RNTI to the at least two RAR messages that are sent, where the C-RNTI is used to perform random access failure and re-initiation when the UE uses the received RAR message During random access, a random access procedure is initiated according to the C-RNTI.
The network device according to claim 16, wherein the processing mode is further configured to add different C-RNTIs in the at least two RAR messages.
A terminal device, comprising:

a sending module, configured to send a random access request message to the network device by using a random number;

And a processing module, configured to detect at least two RAR messages sent by the network device within a set time period; and perform random access according to any RAR message received.
The terminal device according to claim 18, wherein the processing module is specifically configured to detect whether there are at least two RAR messages continuously sent by the network device during the set time period.
The terminal device according to claim 18, wherein the processing module is specifically configured to detect whether there is a first RAR message sent by the network device in the first time period;

The terminal device further includes a receiving module, configured to receive the first RAR message;

The sending module is configured to send, after receiving the first RAR message, the message 3 corresponding to the first RAR message to the network device;

The processing module is specifically configured to detect whether there is a message 4 sent by the network device, and if there is no message 4, detect whether there is a second RAR message sent by the network device in the second time period.
The terminal device according to any one of claims 18 to 20, wherein the processing module is further configured to: determine, when the terminal device fails random access, determine a target RAR message from the at least two RAR messages; The C-RNTI is obtained in the RAR message, and the random access procedure is re-initiated by using the C-RNTI.
The terminal device according to claim 21, wherein the processing module is configured to obtain, according to the at least two C-RNTIs, the at least two C-RNTIs; The RAR message that is received by the terminal device in the at least two RAR messages is determined as the target RAR message.
An M2M system, comprising the network device according to any one of claims 12 to 17, and the terminal device according to any one of claims 18 to 22.