CN102625461B - Method and system for random access to heterogeneous network - Google Patents

Abstract

The invention discloses a random access method in a heterogeneous network, comprising: receiving a random access message initiated by a user terminal; grouping all component carriers of the user terminal according to timing advances according to the random access message to form The carrier group: sending a random access response message to the user terminal, so that the user terminal completes random access on the component carriers in the carrier group. The invention also provides a corresponding system for random access in heterogeneous networks, including user terminals and base stations. The method and system for random access in the heterogeneous network provided by the present invention can effectively reduce the problem of resource conflict in the heterogeneous network, and can improve the success rate of random access of the user terminal.

Description

Method and system for random access in heterogeneous network

technical field

The present invention relates to the field of wireless communication, in particular to a random access method and system in a heterogeneous network.

Background technique

In the next-generation broadband wireless communication network, solving the problem of how to support a larger bandwidth under the bandwidth of the current wireless communication system has become a key factor to improve the throughput of user terminals between cells and the average throughput of user terminals. At present, in the Long Term Evolution (LTE, Long Term Evolution) of the Third Generation Partnership Project, it is proposed to use carrier aggregation to effectively support larger bandwidth in the current wireless communication system to meet the needs of the new generation of wireless standards. Requirements for indicators such as throughput and peak rate. Carrier aggregation is a key technology to support larger bandwidth in the future wireless communication system. By aggregating different carriers, a carrier with a larger bandwidth is formed, and a user equipment (UE, User Equipment) with stronger capabilities is supported on the aggregated bandwidth. ), for example, a bandwidth exceeding 100 MHz in the Long Term Evolution-Advanced (LTE-Advanced) technology.

In the existing multi-component carrier aggregation system, there are serious problems in the transmission of the carrier indicator field (CIF, Carrier Indicator Field) and system information (SI, System Information). When CIF and SI are transmitted on a control channel scrambled with Random Access Radio Network Temporary Identifier (RA-RNTI, Random Access Radio Network Temporary Identifier) or Cell Radio Network Temporary Identifier (C-RNTI, Cell Radio Network Temporary Identifier), The CIF and SI indicating resource transfer on each control channel need to be included in the common search interval of each component carrier (CC, ComponentCarriers), which will lead to the lack of resources in the common search interval, and, due to the introduction of new Downlink Control Information (DCI, Downlink Control Information) format, resulting in an increase in the number of blind decoding attempts in the common search interval. At the same time, when the timing advance (TA, Timing Advance) on the CC is one or more, the random access (RA, Random Access) process may be allocated on one or more CCs, so that when the UE is in a Or when the RA process on multiple CCs fails, when the UE performs the cross-carrier RA process, the CIF and SI indicating resource transfer need to be re-set.

Contents of the invention

The main purpose of the present invention is to provide a method for random access in a heterogeneous network, which can effectively reduce the problem of resource conflicts in the heterogeneous network, and can improve the success rate of random access for user terminals.

The present invention provides a random access method in a heterogeneous network, including:

receiving a random access message initiated by the user terminal;

grouping all constituent carriers of the user terminal according to the timing advance according to the random access message to form a carrier group;

Sending a random access response message to the user terminal, so that the user terminal completes random access on the constituent carriers in the carrier group.

Preferably, after performing the grouping of all component carriers of the user terminal according to the timing advance according to the random access message to form a carrier group, the method further includes:

Carrier groups are prioritized according to the interference status of constituent carriers in the cell in the carrier group.

Preferably, the sending a random access response message to the user terminal for the user terminal to complete random access on the constituent carriers in the carrier group specifically includes:

Sending a random access response message to the user terminal, including the carrier indicator field and system information indicated by the control channel scrambled by the random access wireless network temporary identifier;

Scheduling user terminals to initiate random access on the component carriers in the carrier group with high priority, and generating a contention-based solution on the downlink shared channel for user terminals, including the control channel indicated by the scrambled control channel through the wireless network temporary identifier of the cell Carrier indicator field and system information;

The user terminal decodes the carrier indicator field and system information, and ends the random access procedure.

Preferably, before the user terminal initiates random access on a component carrier in the carrier group with high priority, the method further includes:

In the carrier group, a component carrier with the lowest interference in the cell is selected for random access by the user terminal.

Preferably, after the user terminal is executed to decode the carrier indicator field and system information, it further includes:

Judging whether the user terminal successfully decodes the carrier indicator field and the system information, if so, the user terminal succeeds in random access, and ends the random access procedure;

If not, the user terminal initiates a random access message on the component carrier with the lowest interference in the carrier group in order of priority from high to low, until the user terminal succeeds in random access, otherwise, the user terminal fails in random access.

The present invention also provides a random access system in a heterogeneous network, including a user terminal and a base station, and the base station includes:

A receiving module, configured to receive a random access message initiated by a user terminal;

A grouping module, configured to group all constituent carriers of the user terminal according to the timing advance according to the random access message to form a carrier group;

The access module is configured to send a random access response message to the user terminal, so that the user terminal completes random access on the constituent carriers in the carrier group.

Preferably, the base station further includes:

A division module, configured to prioritize the carrier groups according to the interference status of the component carriers in the cell in the carrier group.

Preferably, the access module includes:

The response unit is configured to send a random access response message to the user terminal, including the carrier indicator field and system information indicated by the control channel scrambled by the temporary identifier of the random access wireless network;

The scheduling unit is used to schedule the user terminal to initiate random access on the constituent carriers in the carrier group with high priority, and generate a contention-based solution on the downlink shared channel for the user terminal, including scrambling through the cell wireless network temporary identifier The carrier indicator field and system information indicated by the control channel; after the user terminal decodes the carrier indicator field and system information, the random access procedure ends.

Preferably, the access module further includes:

The selection unit is configured to select, from the carrier group, a component carrier with the lowest interference in the cell for random access by the user terminal.

Preferably, the base station further includes:

A judging module, configured to judge whether the user terminal successfully decodes the carrier indicator field and the system information, and if so, the user terminal succeeds in random access, and ends the random access procedure;

The scheduling module is configured to, if not, schedule the user terminal to initiate a random access message on the component carrier with the lowest interference in the carrier group in order of priority from high to low, until the user terminal succeeds in random access.

In the present invention, all component carriers used by the user terminal are grouped according to the timing advance TA, that is, the component carriers are divided into different carrier groups according to different timing advances, and each carrier group is divided into different carrier groups according to the interference in the cell The smallest component carrier is prioritized according to its interference status to the carrier group it belongs to. With this method, in the subsequent random access process, the carrier indicator field CIF and system information SI only need to be carried and transmitted on the component carrier with the least interference and the most reliable, instead of being included in each component carrier within the public search interval, so as not to cause the problem of lack of resources in the public search interval, that is, the problem of resource conflicts in heterogeneous networks can be effectively reduced, and at the same time, due to the same time window and the preset Within the range of the maximum number of random access times, the user terminal may be allowed to initiate multiple contention-based random access messages, so that the success probability of random access of the user terminal may be greatly improved.

Description of drawings

FIG. 1 is a schematic flowchart of an embodiment of a random access method in a heterogeneous network according to the present invention;

FIG. 2 is a schematic flow diagram of random access in an embodiment of a method for random access in a heterogeneous network according to the present invention;

FIG. 3 is a schematic flowchart of another embodiment of a method for random access in a heterogeneous network according to the present invention;

FIG. 4 is a schematic flowchart of still another embodiment of a method for random access in a heterogeneous network according to the present invention;

FIG. 5 is a schematic structural diagram of a random access system in a heterogeneous network according to the present invention;

FIG. 6 is a schematic structural diagram of a base station in an embodiment of a random access system in a heterogeneous network according to the present invention;

Fig. 7 is a schematic structural diagram of the access module in Fig. 6;

FIG. 8 is a schematic structural diagram of another embodiment of a random access system in a heterogeneous network according to the present invention;

FIG. 9 is a schematic structural diagram of another embodiment of a system for random access in a heterogeneous network according to the present invention.

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Referring to FIG. 1, an embodiment of a method for random access in a heterogeneous network of the present invention is proposed, the method includes:

Step S101, receiving a random access message initiated by a user terminal;

In this embodiment, the base station performs corresponding instructions and configurations on the component carriers in the aggregated carrier system, so that the signaling interaction between the base station and the user terminal on the component carriers can be reduced. When the user terminal needs to perform random access on the component carriers in the aggregated carrier system, it sends a random access message to the base station, and the base station receives the random access message. In this embodiment, the base station will preset a contention-based random access method for the user terminal, that is, set the maximum number of random access times in each time window, and can judge the number of random access times in the time window based on the number of random access times. random access is successful or failed.

Step S102, grouping all constituent carriers of the user terminal according to the timing advance according to the random access message to form a carrier group;

After receiving the random access message initiated by the user terminal, it will first analyze all the link information of the user terminal that initiated the random access message, and group all the component carriers used by the user terminal according to the timing advance TA, The component carriers are divided into different carrier groups according to different timing advances.

Step S103, sending a random access response message to the user terminal for the user terminal to complete random access on the constituent carriers in the carrier group.

In this embodiment, when the user terminal initiates a random access message, it will first send a preamble to the base station. After receiving the preamble, the base station will obtain the corresponding channel resource according to the physical random access channel resource of the preamble. The random access wireless network temporarily identifies RA-RNTI, and feeds back a random access response message through the RA-RNTI, that is, sends a random access response message to the user terminal, so that the user terminal can, after receiving the response message, Complete random access on the constituent carriers.

In the above embodiment, the random access method in the heterogeneous network further includes:

Step S104, assigning priority to the carrier group according to the interference status of the component carriers in the cell in the carrier group.

After all the component carriers used by the user terminal are divided into different carrier groups according to the timing advance TA, in each carrier group, a component carrier with the least interference in the cell can be found, and according to the interference status of the component carrier , classify the priority of the carrier group it belongs to, that is, the smaller the interference of the component carrier in the cell, the higher the priority level of the carrier group it belongs to, and vice versa, the lower the priority level of the carrier group.

The random access method in the heterogeneous network provided by the present invention is to group all the component carriers used by the user terminal according to the timing advance TA, that is, divide the component carriers into different carrier groups according to different timing advances, And for each carrier group, according to the component carrier with the least interference in the cell, the carrier group where it is located is prioritized according to its interference status. With this method, in the subsequent random access process, the carrier indicator field CIF and system information SI only need to be carried and transmitted on the component carrier with the least interference and the most reliable, instead of being included in each component carrier In the common search interval, the problem of lack of resources in the common search interval will not be caused, that is, the problem of resource conflict in the heterogeneous network can be effectively reduced, and the success rate of random access of the user terminal can be improved at the same time.

Referring to FIG. 2, in an embodiment of the method for random access in a heterogeneous network according to the present invention, step S103 specifically includes:

Step S1031, sending a random access response message to the user terminal, including the carrier indicator field and system information indicated by the control channel scrambled by the random access wireless network temporary identifier;

After receiving the random access message initiated by the user terminal, it will feed back a random access response message to the user terminal through the random access radio network temporary identifier RA-RNTI. In this random access response message, the carrier group includes The carrier indicator field CIF and system information SI initially specified by the component carrier used for control channel indication. In this embodiment, the CIF may include the sum of the component carriers used by the user terminal, the connection mode, the position of the component carrier, the center frequency of the component carrier, and the SI carried by the component carrier. The obtained channel quality of the user terminal changes; while the SI may include information such as carrier center frequency, preamble and synchronization channel position, and it will not change in the subsequent process.

Step S1032, scheduling the user terminal to initiate random access on the component carriers in the carrier group with high priority, and generating a contention-based solution on the downlink shared channel for the user terminal, including the control of scrambling through the cell wireless network temporary identifier Carrier indicator field and system information for channel indication;

After the random access response message fed back by RA-RNTI is sent to the user terminal, it starts to schedule the user terminal to initiate random access according to the timing advance TA. Random access is initiated on the constituent carriers in the carrier group with the highest priority in the group. First of all, the random access initiated by the user terminal refers to the first uplink transmission on the component carrier, and then the base station will generate a contention-based solution on the downlink shared channel for the user terminal, including temporary identification through the wireless network of the cell The carrier indicator field CIF and system information SI indicated by the scrambled control channel, and the first downlink synchronization attempt is performed according to the CIF and SI.

Step S1033, the user terminal decodes the carrier indicator field and system information, and ends the random access procedure.

When the user terminal performs uplink transmission on the component carrier for the first time, and successfully realizes the first downlink synchronization according to CIF and SI, that is to say, the user terminal successfully decodes CIF and SI, at this time, it can be judged After the random access of the user terminal is successful, the random access process can be ended.

According to the first timing advance TA, the first random access of the user terminal is scheduled, so that the user terminal first initiates random access on the component carrier in the carrier group with the highest priority among all the carrier groups used by it, because The component carriers in the carrier group with the highest priority level have the least interference in the cell, so the success rate of the user terminal's first random access can be improved, and the carrier indicator field CIF and system information SI do not need to be included in each within the common search interval of the constituent carriers, so that the problem of lack of resources in the common search interval will not be caused.

Referring to FIG. 3 , another embodiment of the method for random access in a heterogeneous network of the present invention is proposed, and step S103 further includes:

Step S1034, select the component carrier with the lowest interference in the cell from the carrier group, so as to provide random access for the user terminal.

After the random access response message fed back by the RA-RNTI is sent to the user terminal, before the process of scheduling the user terminal to initiate random access according to the timing advance TA, the composition used by the user terminal may also be In the carrier group divided by the carrier according to the timing advance, according to the interference status of all the component carriers in the cell, a component carrier with the lowest interference and the most reliable is selected for the user terminal to initiate random access on this component carrier.

In the carrier group, the component carrier with the lowest interference is selected according to the interference status of the component carrier in the cell for the user terminal to perform the random access process. During the random access process, the carrier indicator field CIF used for the control channel to indicate resource transfer and system information SI can be carried and transmitted only on the selected component carrier with the lowest interference and the most reliable. In this way, it can be further ensured that the CIF and SI do not need to be included in the common search interval of each component carrier, so that the problem of lack of resources in the common search interval will not be caused.

Referring to FIG. 4, another embodiment of the random access method in the heterogeneous network of the present invention is proposed, and the method further includes:

Step S105, judging whether the user terminal has successfully decoded the carrier indicator field and the system information, and if so, the user terminal has succeeded in random access, and ends the random access procedure;

When the user terminal performs uplink transmission on the component carrier for the first time, and performs the first downlink synchronization attempt according to the carrier indicator field CIF and system information SI, that is, when the user terminal performs the step of decoding CIF and SI, it is also necessary to Whether the user terminal can successfully decode CIF and SI is judged, that is, it is judged whether the first random access of the user terminal is successful. If the user terminal successfully decodes CIF and SI, that is, the synchronization according to the first downlink is successfully realized, it can be judged The first random access of the user terminal succeeds, thus ending the random access procedure.

In this embodiment, when the synchronization between random access and downlink fails for the first time, the base station can obtain more link information of user terminals than in the first random access, so the base station may reassign the user terminal to the user terminal. Carriers, and regroup these component carriers according to the timing advance TA, and prioritize the carrier groups formed after grouping, and re-designate the carrier indicator field CIF, and generate a contention-based downlink shared channel for the user terminal s solution.

Step S106, if not, the user terminal initiates a random access message on the component carrier with the lowest interference in the carrier group in order of priority from high to low, until the user terminal succeeds in random access, otherwise, the user terminal fails in random access .

If the user terminal does not successfully decode the CIF and SI, that is, the synchronization based on the first downlink is not achieved, it can be judged that the first random access of the user terminal fails. In order from high to low, random access messages are initiated on the constituent carriers with the lowest interference in other carrier groups except the carrier group selected for the first random access, and similarly judge whether the user terminal can succeed The process of decoding CIF and SI to determine whether the random access is successful. If the user terminal fails to perform random access on the constituent carriers of the carrier groups of all priority levels, or the number of random accesses initiated by the user terminal in the same time window exceeds the maximum preset by the base station for the user terminal At this time, it can be judged that the random access of the user terminal has failed, the base station will disconnect the connection with the user terminal, and the user terminal needs to wait for the next time window, and then re-initiate random access within this time window .

Determine whether the first random access of the user terminal is successful, and when successful, end the random access process; if the first random access fails, it will be in the same time window, in order of priority from high to low, in order A random access message is initiated on the component carrier with the lowest interference in other carrier groups except the carrier group selected for the first random access until the random access is successful. Using this method, within the same time window and within the preset maximum number of random access times, the user terminal can be allowed to initiate multiple contention-based random access messages, thereby increasing the number of user terminals to a large extent. Probability of success for random access.

Referring to Figure 5 and Figure 6, an embodiment of the random access system in the heterogeneous network of the present invention is proposed, the system includes a base station and a user terminal, wherein the base station includes:

The receiving module 10 is configured to receive a random access message initiated by a user terminal;

The grouping module 20 is configured to group all the component carriers of the user terminal according to the timing advance according to the random access message to form a carrier group;

The access module 30 is configured to send a random access response message to the user terminal, so that the user terminal completes random access on the constituent carriers in the carrier group.

In this embodiment, the base station performs corresponding instructions and configurations on the component carriers in the aggregated carrier system, so that the signaling interaction between the base station and the user terminal on the component carriers can be reduced. When the user terminal needs to perform random access on the component carriers in the aggregated carrier system, it will send a random access message to the base station. At this time, the receiving module 10 receives the random access message. In this embodiment, the base station will preset a contention-based random access method for the user terminal, that is, set the maximum number of random access times in each time window, and can judge the number of random access times in the time window based on the number of random access times. random access is successful or failed.

After receiving the random access message initiated by the user terminal, it first analyzes all the link information of the user terminal that initiated the random access message, and the grouping module 20 performs the timing advance TA for all component carriers used by the user terminal. Grouping is performed, and the constituent carriers are divided into different carrier groups according to different timing advances.

In this embodiment, when the user terminal initiates a random access message, it will first send a preamble to the base station. After receiving the preamble, the base station will obtain the corresponding channel resource according to the physical random access channel resource of the preamble. The random access radio network temporarily identifies the RA-RNTI, and feeds back a random access response message through the RA-RNTI, that is, the access module 30 sends a random access response message to the user terminal, so that the user terminal can, after receiving the response message, Random access is done on the constituent carriers in the carrier group.

In the above embodiment, the base station further includes:

A division module 40, configured to prioritize the carrier groups according to the interference status of the component carriers in the cell in the carrier group.

After all the component carriers used by the user terminal are divided into different carrier groups according to the timing advance TA, in each carrier group, a component carrier with the least interference in the cell can be found, and according to the interference status of the component carrier , the division module 40 divides the priority of the carrier group it is in, that is, the smaller the interference of the component carrier in the cell, the higher the priority level of the carrier group it is in, and vice versa, the higher the priority level of the carrier group Low.

The random access system in the heterogeneous network of the present invention groups all the component carriers used by the user terminal according to the timing advance TA, that is, divides the component carriers into different carrier groups according to different timing advances, and each Carrier groups are prioritized according to the component carrier with the least interference in the cell according to the interference status of the carrier group. With this method, in the subsequent random access process, the carrier indicator field CIF and system information SI only need to be carried and transmitted on the component carrier with the least interference and the most reliable, instead of being included in each component carrier In the common search interval, the problem of lack of resources in the common search interval will not be caused, that is, the problem of resource conflict in the heterogeneous network can be effectively reduced, and the success rate of random access of the user terminal can be improved at the same time.

Referring to FIG. 7, in an embodiment of the random access system in a heterogeneous network of the present invention, the access module 30 includes:

The response unit 31 is configured to send a random access response message to the user terminal, including the carrier indicator field and system information indicated by the control channel scrambled by the temporary identifier of the random access wireless network;

The scheduling unit 32 is configured to schedule the user terminal to initiate random access on the component carriers in the carrier group with high priority, and generate a contention-based solution on the downlink shared channel for the user terminal, which includes adding a temporary identifier through the wireless network of the cell. The carrier indicator field and system information indicated by the scrambled control channel; after the user terminal decodes the carrier indicator field and system information, the random access procedure ends.

After receiving the random access message initiated by the user terminal, the response unit 31 will feed back a random access response message to the user terminal through the random access radio network temporary identifier RA-RNTI, in which the random access response message includes The carrier indicator field CIF and system information SI initially designated by the constituent carriers in the carrier group are used for control channel indication. In this embodiment, the CIF may include the sum of the component carriers used by the user terminal, the connection mode, the position of the component carrier, the center frequency of the component carrier, and the SI carried by the component carrier. The obtained channel quality of the user terminal changes; while the SI may include information such as carrier center frequency, preamble and synchronization channel position, and it will not change in the subsequent process.

After sending the random access response message fed back by RA-RNTI to the user terminal, the scheduling unit 32 starts to schedule the user terminal to initiate random access according to the timing advance TA. At this time, the user terminal will Random access is initiated on the constituent carriers in the carrier group with the highest priority among all the carrier groups. First of all, the random access initiated by the user terminal refers to the first uplink transmission on the component carrier, and then the base station will generate a contention-based solution on the downlink shared channel for the user terminal, including temporary identification through the wireless network of the cell The carrier indicator field CIF and system information SI indicated by the scrambled control channel, and the first downlink synchronization attempt is performed according to the CIF and SI.

When the user terminal performs uplink transmission on the component carrier for the first time, and successfully realizes the first downlink synchronization according to CIF and SI, that is to say, the user terminal successfully decodes CIF and SI, at this time, it can be judged After the random access of the user terminal is successful, the random access process can be ended.

According to the first timing advance TA, the first random access of the user terminal is scheduled, so that the user terminal first initiates random access on the component carrier in the carrier group with the highest priority among all the carrier groups used by it, because The component carriers in the carrier group with the highest priority level have the least interference in the cell, so the success rate of the user terminal's first random access can be improved, and the carrier indicator field CIF and system information SI do not need to be included in each within the common search interval of the constituent carriers, so that the problem of lack of resources in the common search interval will not be caused.

Referring to FIG. 8 , another embodiment of the random access system in the heterogeneous network of the present invention is proposed, and the access module 30 further includes:

The selection unit 33 is configured to select, from the carrier group, a component carrier with the lowest interference in the cell for random access by the user terminal.

After sending the random access response message fed back by the RA-RNTI to the user terminal, before performing the process of scheduling the user terminal to initiate random access according to the timing advance TA, the selection unit 33 may also perform Among the carrier groups divided by the used component carriers according to the timing advance, a component carrier with the lowest interference and the most reliable is selected according to the interference status of all component carriers in the cell, so that the user terminal can initiate random access on this component carrier.

In the carrier group, the component carrier with the lowest interference is selected according to the interference status of the component carrier in the cell for the user terminal to perform the random access process. During the random access process, the carrier indicator field CIF used for the control channel to indicate resource transfer and system information SI can be carried and transmitted only on the selected component carrier with the lowest interference and the most reliable. In this way, it can be further ensured that the CIF and SI do not need to be included in the common search interval of each component carrier, so that the problem of lack of resources in the common search interval will not be caused.

Referring to FIG. 9, another embodiment of the random access system in the heterogeneous network of the present invention is proposed, and the base station further includes:

A judging module 50, configured to judge whether the user terminal has successfully decoded the carrier indicator field and the system information, and if so, the random access of the user terminal is successful, and ends the random access process;

The scheduling module 60 is configured to, if not, schedule the user terminal to initiate a random access message on the component carrier with the lowest interference in the carrier group in order of priority from high to low until the user terminal succeeds in random access.

When the user terminal performs uplink transmission on the component carrier for the first time, and performs the first downlink synchronization attempt according to the carrier indicator field CIF and system information SI, that is, when the user terminal performs the step of decoding CIF and SI, the judging module 50 It is also necessary to judge whether the user terminal can successfully decode the CIF and SI, that is, to judge whether the first random access of the user terminal is successful. If the user terminal successfully decodes the CIF and SI, that is, the synchronization according to the first downlink is successfully realized. Then it can be judged that the first random access of the user terminal is successful, thereby ending the random access process.

In this embodiment, when the synchronization between random access and downlink fails for the first time, the base station can obtain more link information of user terminals than in the first random access, so the base station may reassign the user terminal to the user terminal. Carriers, and regroup these component carriers according to the timing advance TA, and prioritize the carrier groups formed after grouping, and re-designate the carrier indicator field CIF, and generate a contention-based downlink shared channel for the user terminal s solution.

If the user terminal does not successfully decode the CIF and SI, that is, it does not realize the synchronization according to the first downlink, it can be judged that the first random access of the user terminal fails. In the order of priority levels from high to low, random access messages are initiated on the component carriers with the lowest interference in other carrier groups except the carrier group selected at the first random access, and the user is also judged Whether the terminal can successfully decode the CIF and SI to determine whether the random access is successful. If the user terminal fails to perform random access on the constituent carriers of the carrier groups of all priority levels, or the number of random accesses initiated by the user terminal in the same time window exceeds the maximum preset by the base station for the user terminal At this time, it can be judged that the random access of the user terminal has failed, the base station will disconnect the connection with the user terminal, and the user terminal needs to wait for the next time window, and then re-initiate random access within this time window .

Determine whether the first random access of the user terminal is successful, and when successful, end the random access process; if the first random access fails, it will be in the same time window, in order of priority from high to low, in order A random access message is initiated on the component carrier with the lowest interference in other carrier groups except the carrier group selected for the first random access until the random access is successful. Using this method, within the same time window and within the preset maximum number of random access times, the user terminal can be allowed to initiate multiple contention-based random access messages, thereby increasing the number of user terminals to a large extent. Probability of success for random access.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related All technical fields are equally included in the scope of patent protection of the present invention.

Claims (6)

1. A method for random access in a heterogeneous network, comprising: receiving a random access message initiated by the user terminal; grouping all constituent carriers of the user terminal according to the timing advance according to the random access message to form a carrier group; Prioritize the carrier group according to the interference status of the component carriers in the carrier group in the cell; Sending a random access response message to the user terminal for the user terminal to complete random access on the constituent carriers in the carrier group, specifically including: Sending a random access response message to the user terminal, including the carrier indicator field and system information indicated by the control channel scrambled by the random access wireless network temporary identifier; Scheduling user terminals to initiate random access on the component carriers in the carrier group with high priority, and generating a contention-based solution on the downlink shared channel for user terminals, including the control channel indicated by the scrambled control channel through the wireless network temporary identifier of the cell Carrier indicator field and system information; The user terminal decodes the carrier indicator field and system information, and ends the random access procedure. 2. The method according to claim 1, further comprising: In the carrier group, a component carrier with the lowest interference in the cell is selected for random access by the user terminal. 3. The method according to claim 2, further comprising: after the user terminal is executed to decode the carrier indicator field and system information: Judging whether the user terminal successfully decodes the carrier indicator field and the system information, if so, the user terminal succeeds in random access, and ends the random access procedure; If not, the user terminal initiates a random access message on the component carrier with the lowest interference in the carrier group in order of priority from high to low, until the user terminal succeeds in random access, otherwise, the user terminal fails in random access. 4. A random access system in a heterogeneous network, comprising a user terminal and a base station, wherein the base station comprises: A receiving module, configured to receive a random access message initiated by a user terminal; A grouping module, configured to group all constituent carriers of the user terminal according to the timing advance according to the random access message to form a carrier group; An access module, configured to send a random access response message to the user terminal, so that the user terminal completes random access on the constituent carriers in the carrier group; The base station also includes: A division module, configured to prioritize carrier groups according to the interference status of component carriers in the cell in the carrier group; The access module includes: The response unit is configured to send a random access response message to the user terminal, including the carrier indicator field and system information indicated by the control channel scrambled by the temporary identifier of the random access wireless network; The scheduling unit is used to schedule the user terminal to initiate random access on the component carriers in the carrier group with high priority, and generate a contention-based solution on the downlink shared channel for the user terminal, including scrambling through the cell wireless network temporary identifier The carrier indicator field and system information indicated by the control channel; after the user terminal decodes the carrier indicator field and system information, the random access procedure ends. 5. The system according to claim 4, wherein the access module further comprises: The selection unit is configured to select, from the carrier group, a component carrier with the lowest interference in the cell for random access by the user terminal. 6. The system according to claim 4, wherein the base station further comprises: A judging module, configured to judge whether the user terminal has successfully decoded the carrier indicator field and the system information, and if so, the user terminal has succeeded in random access, and ends the random access process; The scheduling module is configured to, if not, schedule the user terminal to initiate a random access message on the component carrier with the lowest interference in the carrier group in order of priority from high to low, until the user terminal succeeds in random access.