WO2012058974A1

WO2012058974A1 - Random access method and device

Info

Publication number: WO2012058974A1
Application number: PCT/CN2011/078752
Authority: WO
Inventors: 韩小江; 张现周; 丁红; 杜高鹏
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-11-05
Filing date: 2011-08-23
Publication date: 2012-05-10
Also published as: CN102469615A; CN102469615B

Abstract

Disclosed are a random access method and device. After receiving a first random access message MSG1 sent by a terminal, a system side sends a random access response MSG2 to the terminal according to a solution, for sending the MSG2, preset or selected according to channel information carried in the MSG1. Through the method and device, the reliability of the random access response in a random access process can be improved, thereby optimizing the random access process.

Description

Random access method and device

Technical field

The present invention relates to the field of mobile communication technologies, and in particular, to a random access method and apparatus. Background technique

In current wireless cellular communication systems, there is basically no power control during random access, no

The MCS (Modulation and Coding Scheme) has no HARQ (Hybrid Automatic Repeat Request) mechanism for MSG2 (the response to random access is a message). Therefore, there is a problem with reliable transmission of MSG2 in the random access process.

At present, the processing of MSG2 has not provided the basis for MCS and power control. When the UE (User Equipment) is at the cell edge or the channel quality is poor, if the MSG2 in the random access process cannot be received correctly, the UE will not be able to access the network and thus cannot be serviced. The channel conditions at this time may be applicable to UEs accessing the network. Because it has a variety of methods for the channel, such as: power control, AMC (Auto Modulation and Coding Scheme), HARQ, TTI bundling (Transmission Time Interval bundling) Set, transfer a packet). Therefore, in this case, whether the terminal can service depends largely on the transmission of MSG2.

At present, regarding the processing of MSG1 (the first message initiated during the random access procedure), since MSG1 uses the correlation sequence, and the detection of MSG1 is detected by the correlation operation of the correlation sequence, it overcomes the poor channel quality. strong ability. At the same time, after sending MSG1 once, MSG2 is not detected within the corresponding window for a long time, the terminal will initiate the next MSG1, and the power is gradually increased. The maximum number of transmissions of MSG1 and the step size of power step-by-step adjustment are broadcast in the cell broadcast information. Therefore, the reliability of MSG1 can be basically solved. For the retransmission configuration of MSG1, see RACH-ConfigCommon in 36.331. The step size is {0.2.4.6}, and the maximum number of times MSG1 is sent is 200. At the same time, MSG1 is carried on the RACH (Random Access Channel) resource. At present, there are three types of RACH preamble sequences, which carry the following three types of information: non-contention access, MSG3 information volume, and ordinary contention access. The terminal selects the RACH preamble sequence according to the state and needs, and sends MSG1.

In summary, the following technical problems exist in the prior art: Due to the transmission reliability problem of the MSG2 in the random access process, the acceptance capability of the network is poor, and the balance of the fault tolerance of the service cannot be achieved, and even the situation is caused. Users with poor cell edges or poor channel quality cannot be included in the network, which affects user satisfaction.

Summary of the invention

The technical problem to be solved by the present invention is to provide a random access method and apparatus, improve the reliability of a random access response (MSG2) in a random access procedure, and optimize a random access procedure.

In order to solve the above technical problem, the present invention provides a random access method, including: after receiving a random access message (MSG1) sent by a terminal, the system side selects according to preset channel information according to channel information carried by MSG1. The transmission scheme of the random access response message (MSG2) sends the MSG2 to the terminal.

Preferably, in the above method,

The transmission scheme of the MSG2 includes any combination of one or more of the following schemes: a modulation coding scheme (MCS), a frequency domain spreading scheme, and a TTI bundling scheme.

Preferably, in the above method,

The preset transmission scheme of the MSG2 includes: a default value of a preset MCS, or a preset threshold of the MCS;

The step of the system side transmitting the MSG2 to the terminal according to the preset transmission scheme of the MSG2 includes: selecting, by using a default value of the MCS or an MCS value within the threshold of the MCS. Said MSG2.

Preferably, in the above method,

The channel information carried by the MSG1 includes a sequence type of the MSG1 sent by the terminal, where the sequence type corresponds to an MCS scheme, a frequency domain spread spectrum scheme, and a TTI bundling scheme of the MSG2. One or several of them;

The system side selects, according to the sequence type of the MSG1, the MSG2 by using one or more of the MCS scheme, the frequency domain spreading scheme, and the TTI bundling scheme corresponding to the sequence type.

Preferably, in the above method,

The terminal selects a sequence type for sending the MSG1 according to the number of transmissions or the transmission power of the MSG1.

Preferably, the above method further includes:

The system side sends the selected MCS scheme for sending the MSG2 to the terminal by using downlink control information;

The terminal performs the receiving and parsing of the MSG2 according to the MCS scheme included in the downlink control information.

Preferably, the above method further includes:

When the system side selects the frequency domain spreading scheme to send the MSG2, the multiple of the frequency domain spreading is notified to the terminal by using the downlink control information or the broadcast message; the terminal performs the MSG2 according to the multiple of the frequency domain spreading. Reception and resolution;

When the system side selects the TTI bundling scheme to send the MSG2, the number of the TTI bundling is notified to the terminal by using downlink control information or a broadcast message;

The terminal performs reception and parsing of the MSG2 according to the number of times of the TTI bundling. The present invention also provides a random access device, including a scheme selection module on the system side and a random access response message (MSG2) sending module, where:

The scheme selection module is configured to: preset a transmission scheme of the MSG2; or, after receiving the random access message (MSG1) sent by the terminal, select a transmission scheme of the MSG2 according to the channel information carried by the MSG1;

The MSG2 sending module is configured to: send a MSG2 to the terminal according to a sending scheme of the MSG2 preset or selected by the scheme selection module;

The sending scheme of the MSG2 includes any combination of one or more of the following solutions: Modulation and coding scheme (MCS), frequency domain spread spectrum scheme, and transmission time interval binding (TTI bundling) scheme.

Preferably, in the above device,

The sending scheme of the MSG2 preset by the scheme selection module includes: a preset default value of the MCS or a threshold value of the MCS;

The MSG2 sending module is configured to: according to the sending scheme of the MSG2 preset by the scheme selection module, select to send the MSG2 by using a default value of the MCS or an MCS value within a threshold of the MCS.

Preferably, the apparatus further includes a sequence type selection module on the terminal side, where:

The sequence type selection module is configured to: select a sequence type for transmitting the MSG1 according to the number of transmissions or the transmission power of the MSG1; wherein the sequence type corresponds to one of an MCS scheme, a frequency domain spreading scheme, and a TTI bundling scheme of the MSG2. Species or several

The scheme selection module is configured to: select one of an MCS scheme, a frequency domain spread spectrum scheme, and a TTI bundling scheme corresponding to the sequence type according to the sequence type of the MSG1 in the channel information carried by the MSG1 Several are the transmission schemes for MSG2.

Preferably, the foregoing apparatus further includes a solution notification module on the system side and an MSG2 receiving module on the terminal side, where:

The scheme notification module is configured to notify the terminal of the MCS scheme of the MSG2 that is used by the MSG2 sending module by using the downlink control information;

The MSG2 receiving module is configured to perform receiving and parsing of the MSG2 according to the MCS solution included in the downlink control information.

Preferably, in the above device, the device further includes a solution notification module on the system side and an MSG2 receiving module on the terminal side, where:

The scheme notification module is configured to: if the MSG2 sending module sends the MSG2 by using a frequency domain spreading scheme, the multiple of the frequency domain spreading is notified to the terminal by using downlink control information or a broadcast message; if the MSG2 sends The module sends the MSG2 by using the TTI bundling scheme, and the number of ΤΉ bundlings is notified to the terminal by using downlink control information or a broadcast message;

The MSG2 receiving module is configured to: when receiving the multiple of the frequency domain spreading, according to the The MSG2 receives and parses the multiple of the frequency domain spreading; when receiving the TTI bundling times, the MSG2 receives and parses according to the number of the TTI bundling. BRIEF abstract

FIG. 1 is a flowchart of random access of a terminal according to an embodiment of the present invention;

2 is a flowchart of processing and transmitting MSG2 on the system side according to an embodiment of the present invention;

3 is a schematic diagram of a 3 times TTI bundling according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of 2 times frequency domain spreading according to an embodiment of the present invention. Preferred embodiment of the invention

To solve the problem existing in the prior art, the present embodiment provides a random access method, which specifically uses the following technical solutions:

After receiving the MSG1 sent by the terminal, the system side sends the MSG2 to the terminal according to a preset transmission scheme of the MSG2 selected according to the channel information carried by the MSG1.

The sending scheme of the MSG2 includes one of the following solutions or any combination thereof: an MCS scheme, a frequency domain spreading scheme, and a TTI bundling scheme.

Further, the preset sending scheme of the MSG2 includes: a preset default value of the MCS, or a threshold value of the MCS;

The system side sends the MSG2 by selecting a default value of the MCS or an MCS value within the threshold according to the preset transmission scheme of the MSG2.

Further, the channel information carried by the MSG1 includes a sequence type of the MSG1 sent by the terminal, where each of the sequence types is combined with an MCS scheme of the MSG2, and/or a frequency domain spreading scheme, and/or a TTI bundling scheme. - corresponding;

The system side sends the MSG2 according to the sequence type of the MSG1, selecting an MCS scheme corresponding to the sequence type, and/or a frequency domain spreading scheme, and/or a TTI bundling scheme.

Further, the terminal selects a sequence type for sending the MSG1 according to the number of transmissions or the transmission power of the MSG1. Further, the method further includes:

The system side notifies the terminal by using the DCI (downlink control information) of the MCS scheme that sends the MSG2 that is selected by the system side;

The terminal performs reception and parsing of the MSG2 according to an MCS scheme included in the DCI.

Further, the method further includes:

After selecting the frequency domain spreading scheme and/or the ΤΉbundling scheme of the MSG2, the system side notifies the terminal of the frequency domain spreading multiple and/or the number of TTI bundling to the terminal by using downlink control information or a broadcast message;

The terminal performs reception and parsing of the MSG2 according to a multiple of the frequency domain spreading and/or a number of TTI bundlings.

In order to facilitate the description of the present embodiment, the following description will be further described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the features of the embodiments and the embodiments of the present application can be arbitrarily combined with each other without conflict. FIG. 1 is a schematic flowchart of a terminal initiating random access according to an embodiment of the present invention. As shown in FIG. 1 , the process is specifically described as follows:

Step 101: The terminal needs to initiate random access, initialize various types of access parameters, and initialize the number of times of sending MSG1 to 0;

Step 102, determining that the number of MSG1 transmissions is greater than the maximum number of transmissions, and if so, ending the process; otherwise, performing the next step 103;

Step 103: The terminal selects the RACH preamble sequence, and the number of transmissions of the MSG1 is + 1; in this embodiment, the terminal selects different types of RACH preamble sequences according to the transmit power and/or the number of transmissions of the MSG1. The system side selects the MCS scheme of MSG2 through the type of RACH preamble sequence information in the channel information carried by MSG1.

Each of the preamble sequence types corresponds to an MCS scheme, a frequency domain spreading scheme, or a TTI bundling scheme of the MSG2. When the system side receives the MSG1, the MSG1 may be configured according to the MSG1. The sequence type of the MCS scheme corresponding to the sequence type, the frequency domain spreading scheme, and/or the ΤΉ bundling scheme are selected as the MCS scheme of the MSG2.

Specifically, the terminal according to the number of transmissions/power, when the number of transmissions/power is greater than a predetermined threshold, the direction of the transmission scheme corresponding to the selected sequence type should be to lower the MCS or use TTI bundling.

Step 104, the terminal starts timing, and detects MSG2 in the corresponding time window;

Step 105, it is determined whether MSG2 is detected in the corresponding time window, if it is detected, the next step 106 is performed, otherwise, return to step 102;

Step 106: The terminal initiates the MSG3 according to the authorization information of the MSG2, and completes the random access process, and the process ends.

In this implementation manner, the sequence type of the MSG1 sent by the terminal may correspond to a certain default value or threshold of the MCS, or a default frequency domain M times spread spectrum, or a TTI bundling number N. M, N is a positive integer.

In addition, after determining the transmission scheme of the MSG2, the system may notify the terminal of the determined MCS scheme by using the DCI control information, or notify the multiple of the frequency domain spreading M and/or the number N of the TTI bundling by the control message or the broadcast message. Terminal

The terminal completes the reception of MSG2 according to the MCS scheme, the multiple of the frequency domain spread spectrum, and/or the number of TTI bundlings.

The TTI bundling technology of the MSG2 starts from the downlink subframe of the MSG2, and the consecutive N downlink subframes carry the same MSG2 information or are respectively carried according to the redundancy version of the HARQ. The terminal receives the MSG2 and parses it according to the TTI bundling technique to merge the MSG2s of multiple subframes. Improve the decoding capability of MSG2, thereby improving the transmission reliability of MSG2.

FIG. 2 is a schematic diagram showing the flow of sending MSG2 after the system side receives the MSG1 according to the embodiment of the present invention. As shown in Figure 2, the process mainly includes the following steps:

Step 201: The system side simultaneously confirms the type of the RACH preamble sequence for transmitting the MSG1 according to the detected MSG1.

Step 202: The system side determines, according to the MSG1 sequence type, a sending scheme of the MSG2. For example, the system side determines, according to the sequence type of the MSG1, that the transmission scheme of the MSG2 is an MCS scheme, a frequency domain spreading scheme, or a TTI bundling scheme corresponding to the sequence type.

Step 203: The system sends MSG2 according to the detected MSG2 group MSG2 information according to the determined MSG2 sending scheme, and the process ends.

In this embodiment, the sequence type of the MSG1 sent by the terminal may correspond to a certain default value or threshold of the MCS, or the default frequency domain M times spread spectrum, or the number of TTI bundling times N. M, N is a positive integer.

FIG. 3 is a schematic diagram of a 3 times TTI bundling in the embodiment of the present invention. The TTI bundling technology of the MSG2 means that, from the downlink subframe of the MSG2, the consecutive N downlink subframes (DL subframes) carry the same MSG2 information or are respectively carried according to the redundancy version of the HARQ. The terminal receives the MSG2, parses according to the TTI bundling technique, and merges the MSG2 of the multiple subframes. Improve the decoding capability of MSG2, thereby improving the transmission reliability of MSG2.

FIG. 4 is a schematic diagram of 2 times frequency domain spreading in the embodiment of the present invention. The frequency domain spread spectrum M times means that the same MSG2 information is carried by using M frequency domain resources (spreading blocks 1 , 2 ... , M ). Combination diagram

4. The receiving end combines the data received by the two code blocks, thereby improving the transmission quality.

Embodiment 2

In this embodiment, the system side sends the MSG2 according to the preset transmission scheme of the MSG2, and the preset transmission scheme of the MSG2 includes one of the following solutions or any combination thereof: MCS scheme, frequency domain spread spectrum scheme, TTI bundling Program.

For example, the system side sets the MCS to a default value for MSG2, for example, it is fixedly set to 4. For all MSG2 scheduling, MCS uses the MCS option of 4. In addition, it can also be set The number of times the default frequency domain M times spread spectrum or TTI bundling.

Alternatively, the system side can also set a reasonable threshold for the MCS of the MSG2 through simulation analysis, and use the MCS within the threshold for the MSG2 scheduling of the access terminal in the cell. For example, set this threshold to 12, that is, the MCS selection for MSG2 scheduling is: 0, 1 ... 12.

In addition, after selecting the transmission scheme of the MSG2, the system may notify the terminal of the determined MCS scheme by using the DCI control information; the terminal does not need special processing for the processing of the MSG2, and may be based on the decoding scheme included in the received control information (such as DCI). Finally, the data of MSG2 is parsed.

In addition, regarding the use of TTI bundling of MSG2, several ΤΉ should be used for bundling, which can be obtained according to simulation analysis. At the same time, the TTI bundling selection scheme of MSG2 is delivered by the broadcast information in the cell. The terminal acquires the transmission mode of the MSG2 of the cell from the received broadcast information. During the terminal access process, when receiving the MSG2, the receiving process is performed according to the corresponding number of TTI bundlings. When the TTI bundling is delivered according to various HARQ modes, the terminal performs the merge analysis according to the HARQ merge mode after receiving the corresponding bundling. At present, the HARQ mode mainly includes: each ΤΉ sends the same data packet, the first subframe delivers the data packet, and the subsequent subframe delivers a redundant version of the HARQ.

The TTI bundling solution can be delivered to all terminals in the cell through broadcast information, or sent to the terminal through control information when the data is delivered. For example, according to the simulation, two TTI bundlings can satisfy the transmission performance of the MSG2, and the MSG2 transmission scheme is delivered in the cell broadcast information. Currently, the broadcast information of MSG2 is in SIB2 (SystemInformationBlockType2, Type2 system message block), and the corresponding data bit can be added in SIB2 to carry the scheme selection information of TTI bundling of MSG2. Or by sending the control information of the data, the TTI bundling data bit may be added to the control information type for the MSG2, thereby indicating that the packet data uses the TTI bundling scheme, and indicates that the TTI bundling scheme, such as N TTIs, is tied. set.

In addition, the present embodiment further provides a random access device, which mainly includes a solution selection module on the system side and a MSG2 transmission module, where:

The scheme selection module is configured to preset a transmission scheme of the MSG2; or, after receiving the MSG1 sent by the terminal, select a transmission scheme of the MSG2 according to the channel information carried by the MSG1; The MSG2 sending module is configured to send a MSG2 to the terminal according to a sending scheme of the MSG2 preset or selected by the scheme selection module;

The transmission scheme of the MSG2 includes one of the following schemes or any combination thereof: a modulation coding scheme (MCS), a frequency domain spreading scheme, and a ΤΉbundling scheme.

Preferably, the sending scheme of the MSG2 preset by the scheme selection module includes: a preset default value of the MCS, or a threshold value of the MCS;

The MSG2 sending module sends the MSG2 according to a default value of the MCS or an MCS value within the threshold according to a sending scheme of the MSG2 preset by the scheme selection module.

Preferably, the device further includes a sequence type selection module on the terminal side, where:

The sequence type selection module is configured to: select, according to the number of transmissions or the transmission power of the MSG1, a sequence type for transmitting the MSG1; wherein each of the sequence types and the MCS scheme of the MSG2, and/or the frequency domain spread spectrum scheme, and / or TTI bundling program - corresponding;

The scheme selection module is configured to select, according to the sequence type of the MSG1 in the channel information carried by the MSG1, an MCS scheme, and/or a frequency domain spreading scheme, and/or a TTI bundling scheme corresponding to the sequence type. MSG2 transmission scheme.

Preferably, the device further includes a solution notification module on the system side and an MSG2 receiving module on the terminal side, where:

The scheme notification module is configured to notify the selected terminal of the selected MCS scheme of the MSG2 by using downlink control information;

The scheme notification module is configured to notify the terminal of the multiple of the frequency domain spreading and/or the number of the TTI bundling by using the downlink control information or the broadcast message after selecting the frequency domain spreading scheme and/or the ΤΉ bundling scheme of the MSG2. ;

The MSG2 receiving module is configured to perform receiving and parsing of the MSG2 according to a multiple of the frequency domain spreading and/or a number of TTI bundlings. The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. The present invention may be embodied in various other embodiments without departing from the spirit and scope of the invention. It is within the scope of the appended claims.

Obviously, those skilled in the art should understand that the above functional modules or steps can be implemented by a general computing device, which can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be executed in a different order than herein. The steps shown or described are either made separately into individual integrated circuit functional modules, or a plurality of functional modules or steps are fabricated as a single integrated circuit functional module. Thus, the invention is not limited to any particular combination of hardware and software.

Industrial Applicability The present invention provides a random access method and apparatus for improving random access response in a random access procedure

(MSG2) reliability, optimizing the random access process. The transmission reliability and network acceptance capability of the MSG2 in the random access process are enhanced, and the balance between the fault tolerance and the service is improved, and the user satisfaction is improved.

Claims

Claim

1. A random access method, comprising:

After receiving the random access message (MSG1) sent by the terminal, the system side sends the MSG2 to the terminal according to a preset transmission scheme of the random access response message (MSG2) selected according to the channel information carried by the MSG1.

2. The method of claim 1 wherein

3. The method according to claim 1 or 2, wherein

4. The method according to claim 1 or 2, wherein

The channel information carried by the MSG1 includes a sequence type of the MSG1 sent by the terminal, where the sequence type corresponds to one or more of an MCS scheme, a frequency domain spread spectrum scheme, and a TTI bundling scheme of the MSG2;

5. The method of claim 4, wherein

6. The method of claim 3, further comprising:

The system side sends the selected MCS scheme for sending the MSG2 to the terminal by using downlink control information; The terminal performs receiving and parsing of the MSG2 according to an MCS scheme included in the downlink control information.

7. The method of claim 4, further comprising:

The terminal performs reception and parsing of the MSG2 according to the number of times of the TTI bundling.

8. A random access device, comprising: a system selection module and a random access response message (MSG2) sending module, wherein:

The transmission scheme of the MSG2 includes any combination of one or more of the following: a modulation and coding scheme (MCS), a frequency domain spreading scheme, and a TTI bundling scheme.

9. The apparatus according to claim 8, wherein

10. The apparatus of claim 8, further comprising a sequence type selection module on the terminal side, wherein: The sequence type selection module is configured to: select a sequence type for transmitting the MSG1 according to the number of transmissions or the transmission power of the MSG1; wherein the sequence type corresponds to one of an MCS scheme, a frequency domain spreading scheme, and a TTI bundling scheme of the MSG2. Species or several

The apparatus according to claim 8 or 9, further comprising a scheme notification module on the system side and an MSG2 receiving module on the terminal side, wherein:

The device according to claim 8 or 10, wherein the device further comprises a system notification module on the system side and an MSG2 receiving module on the terminal side, wherein:

The MSG2 receiving module is configured to: when receiving the multiple of the frequency domain spreading, perform the receiving and parsing of the MSG2 according to a multiple of the frequency domain spreading; when receiving the TTI bundling number, according to the The number of TTI bundlings is described for the reception and parsing of the MSG2.