WO2015085688A1

WO2015085688A1 - Method and system for accessing cognitive spectrum by lte system

Info

Publication number: WO2015085688A1
Application number: PCT/CN2014/075056
Authority: WO
Inventors: 周一青; 刘玲; 田霖; 石晶林
Original assignee: 中国科学院计算技术研究所
Priority date: 2013-12-09
Filing date: 2014-04-10
Publication date: 2015-06-18
Also published as: CN103596288B; CN103596288A

Abstract

The present invention provides a method and a system for accessing a cognitive spectrum by an LTE system. The method for accessing a cognitive spectrum by an LTE system comprises: a UE implementing a start-up process on an LTE authorized spectrum; and when a load rate of the LTE authorized spectrum exceeds a threshold, dispatching the UE needing random access to a cognitive spectrum to work, or the UE working on the LTE authorized spectrum; otherwise, the UE working on the LTE authorized spectrum. By optimizing a protocol, the present invention provides a solution for using a cognitive radio technology in an LTE system, and the solution is backwards compatible with the LTE system; the communication quality is ensured, and the work spectral range of the LTE system is expanded, thereby avoiding complex operations of frequent quitting and re-access by a user, and achieving the objective of saving energy.

Description

Method and system for LTE system accessing cognitive frequency"

The present invention relates to an LTE protocol optimization technology, and in particular, to a method and system for accessing a cognitive frequency in an LTE system.

The background technology, the , and the technology can solve the contradiction between the current low utilization rate of spectrum resources and the scarcity of spectrum resources. Cognitive radio technology enables unlicensed users to access the idle frequency band through perceptual and opportunistic access, which can effectively improve the utilization of existing spectrum and provide technical support for the development of future communication systems. The application of cognitive radio technology to existing communication systems can change the resource shortage and utilization of the fixed spectrum management of existing communication systems through dynamic spectrum access.

At present, the resources allocated to LTE (such as TD-LTE) under the fixed-frequency allocation policy are limited. With the development of large-scale commercial trials of LTE, the lack of spectrum resources has become a bottleneck restricting the deployment and development of LT E. In LTE The introduction of cognitive radio technology, through the opportunistic use of other system idle spectrum resources, can expand the spectrum use range of TD-LTE, solve the problem of lack of spectrum resources, and provide sufficient spectrum support for LTE operations. Utilize the advantages of signal propagation characteristics of certain frequency bands (such as low-frequency broadcast TV bands) to obtain better communication quality. Since LTE system has wide frequency band and multi-band characteristics, the introduction of cognitive radio technology in LTE system can expand LTE. The flexibility of system spectrum usage, improve spectrum utilization, and generate new value growth points. With the advancement of LTE system industrialization process, users' demand for higher bandwidth transmission of high-speed data services will become more and more obvious, thus enabling The future of LTE systems for cognitive radio technology will become more widespread. Based on the mastery of key technologies, the application of cognitive radio in LTE systems will be carried out to provide solutions for the application of cognitive radio technology in LTE systems, which will provide a technical basis for the sustainable development of LTE.

At present, there is no clear standard and solution for applying CR technology to the LTE system to support the operation of the LTE system on the idle spectrum of other systems. For the cognitive wireless user access network, the prior art includes: the cognitive user applies for the access authorization network, and the authorized network allocates the temporary access code or other means to guide the cognitive user to access; and, through the cognitive The acquisition of spectrum enables cognitive users to access the cognitive network to work. First technical side The case requires an authorized network to assist the cognitive user's access process, and the existing network changes are relatively large. Most of the second technical solutions involve the design of cognitive wireless network architecture, which supports the operation of cognitive networks by designing multiple modules that implement cognitive functions. This scheme is based on the idle spectrum of existing networks. Acquiring and effectively utilizing to support the communication process of the cognitive network, the process of management and interaction of the network unit has been greatly changed. Summary of the invention

In order to introduce the CR technology in the LTE system, the working frequency band of the LTE system is extended to the licensed frequency band of the LTE and the available idle frequency band of other systems (hereinafter referred to as "cognitive spectrum"), and the present invention provides an LTE system connection. The method for entering the cognitive spectrum, the method includes: Step 1), the UE completes a boot process on the LTE licensed spectrum;

Step 2: According to the load rate of the LTE licensed spectrum, the UE that needs to perform random access is scheduled to work in cognitive spectrum or the UE operates at the LTE authorized frequency.

In an embodiment, the step 2) includes: when the load rate of the LTE licensed spectrum exceeds a threshold, scheduling the UE that needs to perform random access to work in cognitive spectrum, or the UE works in the LTE licensed spectrum Otherwise, the UE works in the LTE licensed spectrum.

In a further embodiment, in step 2), when the load rate of the LTE licensed spectrum exceeds a threshold, if the service priority is low, the UE that needs to perform random access is scheduled to work in the cognitive spectrum; If the service priority is high, the UE that needs to perform random access works in the LTE licensed spectrum.

In an embodiment, before step 2), the method further comprises:

Step a), the UE initiates a random access request to the current base station;

Step b), the random access decision module of the current base station determines the load status of the LTE licensed spectrum, and returns a random access response including the service priority setting information and the cognitive spectrum information if the load rate exceeds the threshold; otherwise, returns Standard random access response.

In a further embodiment, step 2) comprises:

Step 211), when the load rate of the LTE licensed spectrum exceeds a threshold, perform step 212); otherwise, the UE that needs to perform random access completes random access according to the existing LTE protocol, enters the CONNECTED state, starts communication, and Skip steps 212) and 213);

Step 212), the UE that needs to perform random access determines whether the priority of the initiating service is high or low according to the service priority setting information, and if the service priority is low, step 213); Otherwise, the UE completes random access according to the existing LTE protocol, enters the CONNECTED state to start communication, and skips step 213);

Step 213: The UE that needs to perform random access performs cell selection and frequency camping according to the cognitive spectrum information, enters an IDLE state, and then the UE initiates random access, completes random access, enters a CONNECTED state, and starts Communication.

In another embodiment, before step 2), the method further includes:

And if the real-time load rate of the LTE licensed spectrum exceeds a threshold, sending a first system message indicating that the second system message is received to all UEs, and broadcasting a second system message carrying the cognitive spectrum information.

In an embodiment, before step 2), the method further comprises: if the load rate drops to the threshold, updating the first system message, indicating that all users no longer receive the second system message. In another embodiment, before step 2), the method further comprises: stopping the broadcasting of the second system message if the load rate drops to the threshold.

In a further embodiment, step 2) comprises:

Step 221), when the load rate of the LTE licensed spectrum exceeds a threshold, perform step 222); otherwise, the UE that needs to perform random access completes random access according to the existing LTE protocol, enters the CONNECTED state, and starts communication, and Skip step 222) and 223);

Step 222): The UE that needs to perform random access determines whether the priority of the initiating service is high or low. If the service priority is low, step 223) is performed; otherwise, the UE completes random access according to the existing LTE protocol, and enters CONNECTED. The state begins to communicate and skips step 223);

Step 223: The UE that needs to perform random access receives the second system message, performs cell selection and frequency camping according to the cognitive spectrum information in the latest second system message, enters an IDLE state, and then the UE initiates a random After accessing, after completing random access, it enters the CONNECTED state and starts communication.

In one embodiment, the second system message is a new system message carrying cognitive spectrum information. In another embodiment, the second system message is an existing system message with increased cognitive spectrum information.

In an embodiment, step 2) further comprises determining a priority of the UE initiating the service.

In a further embodiment, determining the priority of the UE initiating the service comprises:

When the load ratio of the LTE licensed spectrum is 1, it is determined that the priority of all initiated services is Low; when the load rate of the LTE licensed spectrum is between the threshold and 1, the priority is determined to be high or low according to the type of service.

In one embodiment, step 1) includes:

The UE performs PLMN selection, cell search, cell selection and reselection, and frequency residing on the LTE licensed spectrum, and then enters the IDLE state.

According to an embodiment of the present invention, a system for accessing a cognitive spectrum by an LTE system is provided, including: a startup module, configured to complete a boot process on a LTE licensed spectrum; and an admission control module, configured to determine a service priority And, according to the service priority setting and the load rate and the load threshold, scheduling the UE that needs to perform random access to perform cognitive spectrum work or the UE works in the LTE authorized spectrum.

The following beneficial effects can be achieved by the invention:

a) Based on the existing TD-LTE protocol mechanism modification to support the LTE system to use the cognitive spectrum, the existing protocol changes are small, which is conducive to backward compatibility. By modifying and adding the SIB message, the UE is reasonably scheduled according to the load status and the service priority before the random access procedure, or the UE is reasonably scheduled by modifying the random access response form. When the LTE frequency load is heavy, some users are scheduled to the cognitive spectrum, and the working spectrum range of the LTE system is expanded to support more L TE users.

b) Since the licensed spectrum is a dedicated spectrum of a communication system, communication over the licensed spectrum is more reliable, communication quality is better, and continuity is better. Therefore, the scheme considers that the user will be scheduled to the cognitive spectrum only when the licensed spectrum load of the LTE system is heavy, and the use of the cognitive spectrum is supported under the premise that the existing protocol changes are as small as possible, and the LTE system is expanded. The working spectrum ranges, but still guarantees that the communication quality is within the user's acceptance.

c) Compared with the scheme of directly accessing the cognitive frequency, it avoids the cumbersome operation of frequently retreating and re-accessing other available idle spectrum when the user is in the IDLE state, if the primary user on the cognitive spectrum appears, only in the It is possible to access cognitive spectrum communication when entering the CONNECTED state.

d) adding a system message in the LTE system or adding a random access response form to inform the user of the cognitive spectrum related information, and does not require the user to perform a spectrum sensing process, which may be performed by a single cognitive base station or multiple cognitive base stations. After the collaboration is completed, the spectrum sensing result is characterized by the newly added system message or another newly added random access response format, which achieves the purpose of energy saving. DRAWINGS

1 is a flowchart of a method for admission control of an LTE system according to an embodiment of the present invention; FIG. 2 is a schematic diagram of cognitive spectrum access interaction according to an embodiment of the present invention;

3 is a flow chart of a method for an LTE system to access a cognitive spectrum according to an embodiment of the present invention;

4 is a schematic diagram of cognitive spectrum access interaction according to another embodiment of the present invention; and FIG. 5 is a flowchart of a method for an LTE system to access a cognitive spectrum according to another embodiment of the present invention. detailed description

The invention will now be described with reference to the drawings and specific embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Before describing the method and implementation method for supporting the LTE system access cognitive spectrum provided by the present invention, the existing LTE protocol is briefly introduced.

In the LTE protocol, a user terminal (UE, or simply a user) performs a process of performing PLMN selection, cell search, cell selection and reselection, and camping according to initial cell selection or cell selection based on stored information, and enters IDLE. status. After the random access procedure is initiated, the IDLE state is changed to the CONNECTED state. In the IDLE state, the UE performs operations such as monitoring a paging channel, neighboring cell measurement and reselection, and receiving a system broadcast message. The communication process can be performed after the IDLE state is changed to the CONNECTED state. There are several reasons for triggering random access: initial access in the IDLE state, the UE receives the paging message to enter the cell, the UE that receives the handover command needs to enter the target cell, and the radio link fails to reestablish the RRC connection. The uplink or downlink data arrives but the UE is not synchronized with the evolved base station (eNB, or simply the base station).

Based on the existing LTE protocol, according to an embodiment of the present invention, a method for accessing a cognitive spectrum by an LT E system is provided.

Briefly, the method sets the UE in the IDLE state to be distributed on the licensed spectrum, and the UE in the CONNE CTED state is distributed on the cognitive spectrum and the licensed spectrum. According to the admission control, when the ID LE state enters the CONNECTED state, when the authorized frequency load is light, it is considered to work in the licensed spectrum, and when the authorized spectrum load is heavy, it is considered to schedule some UEs to the cognitive spectrum. In terms of how to use the cognitive spectrum, it is considered that it is necessary to re-access to the cognitive spectrum, and the control channel and the traffic channel are simultaneously divided in the cognitive spectrum according to the LTE system. In addition, the control letter can also be The track stays in the licensed spectrum, where the cognitive spectrum is only used for service transmission. In this case, the terminal needs to be able to support the simultaneous operation on the cross-carrier, and is applicable to the carrier aggregation/multi-carrier scenario. In the following, only a single carrier scenario is considered, that is, the control channel and the traffic channel are simultaneously divided on the cognitive spectrum, and is compatible with the LTE system. If the cognitive spectrum is insufficient (required to reserve the spectrum resource as the spectrum concession, and the cognitive spectrum usage rate is counted, and the spectrum is considered to be insufficient than a certain threshold), the access is denied. Figure 1 shows the admission. Flow chart of the control method.

In this embodiment, after the user is powered on, the user first accesses the licensed spectrum. If the load is heavy, the user accesses the cognitive spectrum to work in the cognitive spectrum. According to the existing cognitive wireless user access network technology, after the user is turned on, the user can directly access the cognitive spectrum, that is, the user stays on the cognitive frequency after booting up. "Management in the RRC IDLE state and the CON NECTED state is performed. However, in the implementation process, the following problems exist in the implementation process: a) Before accessing the cognitive spectrum, the terminal needs to know the information of the available idle spectrum, and then perform cell search and cell selection in the boot process according to the obtained information. . The acquisition of spectrum information mainly includes methods such as spectrum sensing, database access, and cognitive pilot channel access. However, no matter which method is used to obtain the spectrum information, it will increase the additional energy consumption and time-consuming operation of the terminal.

b) The terminal resides in the cognitive frequency in the IDLE state. If there is a primary user appearing at the cognitive frequency that resides at this time, it is necessary to switch the access frequency point in time, and re-execute the operation of access and resident. Since the user needs to receive system messages, paging messages, etc. in the IDLE state, it is necessary to ensure that the terminal resides at the available frequency points. The activity of the primary user is dynamically changed, so the relinquish of the IDLE state is inevitable, and the number of times of concession It will change as the appearance of the primary user on the frequency of the host changes.

Therefore, the present invention first accesses the licensed spectrum after the user is powered on, so that the UEs in the IDLE state are distributed on the weighted frequency, and the users in the CONNECTED state are distributed on the weighted frequency and the cognitive spectrum, avoiding direct access to The cumbersome operation of the cognitive spectrum and frequent retreats and re-accesses caused by the activity of the primary user.

The method and implementation method for accessing the cognitive spectrum of the LTE system provided by the present invention will be described in detail below.

First, after the user is powered on, the boot process is completed on the LTE licensed spectrum according to the existing LTE protocol, including PLMN selection, cell search, cell selection and reselection, camping, etc., and then enters the IDLE state. In the IDLE state, the LTE user can perform the following operations: 1. Listening to the paging channel, 2. Measuring and reselecting the neighboring cell, 3. Receiving the system broadcast message. Then, considering the random access procedure, after the random access succeeds, the UE enters the CONNECTED state from the IDLE state, and the data transmission and the call process can be performed. In the method, the user initially entering the CONNECTED state is scheduled to the cognitive spectrum or the licensed spectrum according to the admission control method shown in FIG. For the acquisition of cognitive spectrum messages, consider the following two implementation methods: 1. Modify the signaling process related to the random access procedure, 2. Modify and configure the system message before random access, and load the authorized spectrum. The user is informed to receive the corresponding cognitive spectrum message and transfer to the cognitive spectrum. The method for implementing the LTE system access cognitive frequency by modifying the random access procedure and modifying and configuring the system message will be described in detail below.

I. Modification of the signaling process related to the random access process

Considering that when receiving a random access request, the current base station performs a random access response in conjunction with the base station load condition (ie, the load condition of the licensed spectrum). The random access decision module is set on the base station side, and the random access is completed according to the existing LTE protocol flow when the load is light; when the load rate exceeds a certain threshold, the priority of the initiated service is comprehensively considered, according to the random access decision. The service with the highest priority is scheduled on the authorized spectrum, the random access is completed according to the existing process, and the service with the lower priority is scheduled to the cognitive spectrum, and the available idle cognition is notified in the random access response message. Frequency. Then, the user performs cell search, cell selection, and random access procedures according to the received available idle cognitive spectrum message.

In one embodiment, the threshold for determining the weight of the load may be calculated by the base station, and the threshold value range in which user access congestion is easily generated is counted, and the threshold is obtained within the threshold. For example, if a base station has a high access failure rate within a load rate of 85 %-90%, then a value is selected within the range as the threshold of the decision. In another embodiment, it may also be determined by a resource utilization threshold of admission control in the LTE system.

To implement this embodiment, the protocol needs to be modified as follows:

a) Add a random access decision module on the base station side, taking into account the load status and the priority of the service.

b) For random access requests, two random access response formats are provided, one is an existing random access response (or standard random access response;), and the other is to schedule users to the cognitive spectrum. Random access response. 2 shows a schematic diagram of cognitive spectrum access interaction based on a modified random access response message, where "random access response" represents an existing random access response (or standard random access response), "random access" Response 2" is a service priority setting and a random access response for scheduling users to the cognitive spectrum, including, for example, cognitive spectrum information and traffic priority Set the information. The base station selects which random access response message to send according to the random access decision of the random access decision module. After receiving the "random access response 2", the UE compares the type of the initiated service with the service priority setting information in the random access response message, and determines whether to access the licensed spectrum or access the cognitive spectrum ( Dispatching low priority traffic to cognitive spectrum). At this time, if a UE with a low priority service maliciously accesses the licensed spectrum, it will be denied access by the base station. In Fig. 2, although the "cognitive base station" is used to indicate access to the cognitive spectrum, in fact, the access cognitive frequency is also implemented in the current base station.

In an embodiment, the priority of the service priority can be referred to the following service type:

Voice Service > Online Game Service > Video Service > Web Service > File Transfer Service, ie: VoIP>gaming>vediostreaming>HTTP>FTP

In this embodiment, all services are classified into two categories: high priority services and low priority services. The service priority setting (high priority setting and low priority setting) information in "Random Access Response 2" can be adjusted based on feedback from the licensed spectrum load condition. For example, if the licensed spectrum is not idle (eg, the load rate is 1), then all newly accessed services are considered low priority and will be scheduled on the cognitive spectrum; if the load rate is at the threshold (eg to 1) Between, then you can set the top 1-3 business with higher ordering as high priority business.

Figure 3 illustrates the process of accessing a cognitive spectrum or licensed spectrum based on modifications to the random process, including modifying the access response message and adding a random access decision module, including the following steps:

1) the UE initiates a random access request to the current base station;

2) The random access decision module on the base station side determines whether the load rate of the licensed spectrum is greater than the threshold value, if it is greater than 3), otherwise executes 7);

3) the base station sends a random access response 2 (RAR2) to the UE;

4) The UE compares and decides the service priority setting information in the random access response 2 according to the type of the initiated service; if the originating service is a high priority service, it executes 8), otherwise executes 5)

5) The UE performs cell selection and frequency reservation according to the available cognitive spectrum information carried in the RAR2, and enters the IDLE state;

6) The UE entering the IDLE state then initiates random access, completes the random access, enters the CONNECTED state, and starts communication; the process ends.

7) the base station sends a random access response to the UE;

8) The UE completes the subsequent random access procedure according to the existing LTE protocol, and enters the CONNECTED Status, start communication. Second, modify the system message SI before random access

There are two ways to modify the system message: 1. Add a new system message; 2. Do not add system messages, modify existing system messages, which will be described separately below.

1. Add a new system message, such as SIB 17 shown in Table 1.

As described above, the user is scheduled in the cognitive spectrum or the licensed spectrum based on the load condition of the licensed spectrum and the service priority of the UE. As shown in FIG. 4, if the load is light (ie, / ≤ 。), the network side does not guide the terminal access network, and the user at this time can access the 4 authorized frequency. When the load rate exceeds a certain threshold η ₀ , the system message SIB 1 is updated, the message content is added in SIB 1, all UEs are told to receive the system message SIB 17, and the new system message SIB 17 is started to be broadcast. The SIB 17 carries cognitive spectrum related information for use by the LTE system. The idle cognitive spectrum information in the SIB 17 message needs to be updated periodically (e.g., according to a spectrum detection period, such as 200 ms). For users who do not need to perform random access, they do not need to pay attention to this system message. For users who need to perform random access, they need to receive the SIB 17 message and perform frequency access according to the latest SIB 17 message. In a further embodiment, for a user who initiates a low priority service, for example, a user who requests an access service with a low latency priority or a non-real time service or an initial access in an IDLE state, needs to receive the SIB 17, and follow The available frequency point information in the SIB 17 is re-processed by frequency point scanning, cell selection, etc., and then randomly accessed at the selected frequency point to enter the CONNECTED state. For users requesting access delays with high priority or real-time services (ie, users of high-priority services), access to the licensed spectrum. In one embodiment, when the load rate drops, the broadcast SIB 17 is stopped or the SIB 1 is updated to inform the user that the SIB 17 is no longer being received. At this time, the licensed spectrum resources are sufficient, and only random access to the licensed spectrum is considered. Table 1

Figure 5 illustrates the process of accessing a cognitive spectrum or licensed spectrum based on modifying system messages, including the following steps:

1) The UE enters the IDLE state; 2) the UE receives system messages, paging messages, and the like;

3) Determine whether the load rate of the licensed spectrum is greater than the threshold value //. If it is greater than 4); otherwise update SIB17, no longer instruct the UE to receive the SIB17 message, execute 10);

4) Update system message SIB 1, instruct all UEs to receive SIB 17; return to step 3) after a while;

5) judging whether the UE initiates random access, if it is initiated, it executes 6), otherwise it ignores the update content of SIB17;

6) Discriminate the service priority, if it is a low priority service, execute 7), otherwise execute 11);

7) The UE receives the SIB 17 and performs demodulation to acquire the cognitive frequency "related information;

8) The UE performs operations such as cell selection and frequency camping according to the cognitive spectrum information carried in the SIB17, and enters an IDLE state;

9) The UE entering the IDLE state then initiates random access, enters the CONNECTED state after completing the random access, starts communication, returns to 6) or ends the process.

10) the UE continues to receive system messages, paging messages, and the like;

11) The UE initiates a random access procedure on the camped frequency point (ie, the licensed spectrum);

12) After the random access is successful, enter the CONNECTED state, perform the communication process, return to 6) or end the process.

2. Do not add SIB 17, modify the existing system message SIB3

The new SIB17 is mainly used to broadcast available frequency information, and it is also considered to add this information to existing SIB messages. By analyzing the existing SIB message, in one embodiment, the message is added to SIB3. The SIB3 mainly carries the cell reselection related information, including the reselection information of the system information block, including common information of the same frequency, different frequency and different systems, frequency information of the service, and information of partial co-frequency cell reselection. At this time, in order to support the use of cognitive spectrum, the cognitive spectrum information is added to SIB3, and a signaling domain is added to SIB3, as shown in Table 2.

According to the above two solutions, the LTE system provided by the present invention is required to access the cognitive spectrum. The method requires the following modifications to the LTE protocol:

1, for adding new system messages

La) Design the SIB17 message format, the content of the message and its organization and update mechanism. Lb) in SIB1, a signaling field indicating that the SIB17 is received, the update period of the SIB17, and the like, that is, the scheduling information of the SIB17 is added in the SIB1, so that the UE receives the relevant information at the correct location, and also provides the system message. The information is changed so that the UE updates the corresponding system broadcast information.

Lc ) Set a reasonable value.

2, for not adding new system messages

2a) Design the message format of the new signaling domain in SIB3, the content of the message and its organization and update mechanism.

2b) adding a signaling domain indicating SIB3 reception, SIB3 update period, etc., in SIB1, that is, adding SIB3 scheduling information in SIB1, so that the UE receives related information at the correct location, and also provides system messages. The information is changed so that the UE updates the corresponding system broadcast information.

2c) Set a reasonable value.

After the user's random access is successful, whether it is distributed on the licensed spectrum or the cognitive spectrum, normal data transmission or communication can be performed. Users on the licensed spectrum perform mobility management in the CONNECTED state according to the existing protocol. The user on the cognitive spectrum determines whether a spectrum backoff operation is required to maintain communication continuity according to the activity of the primary user of the accessed frequency.

According to an embodiment of the present invention, a system for accessing a cognitive spectrum by an LTE system is further provided, the system comprising a startup module and a scheduling module.

The startup module is used by the UE to complete the boot process on the LTE licensed spectrum. The admission control module is configured to determine the service priority, and based on the service priority setting and the load rate and the load threshold, the UE that needs to perform random access is scheduled to work in cognitive spectrum or the UE works in the LTE licensed spectrum.

It will be appreciated and appreciated that various modifications and improvements can be made to the present invention described above without departing from the spirit and scope of the invention. Therefore, the scope of the claimed technical solutions is not limited by any particular exemplary teachings presented.

Claims

Rights request

1. A method for accessing a cognitive frequency in an LTE system, comprising:

Step 1), the UE completes the boot process on the LTE licensed spectrum;

The method according to claim 1, wherein the step 2) comprises: when the load rate of the LTE licensed spectrum exceeds a threshold, scheduling the UE that needs to perform random access to work in cognitive spectrum, or the UE Working in the LTE licensed frequency;

Otherwise, the UE operates in the LTE licensed spectrum.

3. The method according to claim 2, in step 2), when the load ratio of the LTE licensed spectrum exceeds a threshold,

If the service priority is low, the UE that needs to perform random access is scheduled to work in the cognitive spectrum;

If the service priority is high, the UE that needs to perform random access works in the LTE licensed spectrum.

The method according to any one of claims 1 to 3, wherein before step 2), the method further comprises:

Step a), the UE initiates a random access request to the current base station;

5. The method according to claim 4, wherein step 2) comprises:

Step 212), the UE that needs to perform random access determines whether the priority of the initiating service is high or low according to the service priority setting information, and if the service priority is low, step 213); otherwise, the UE follows the existing LTE. The protocol completes random access, enters the CONNECTED state to start communication, and skips step 213); Step 213: The UE that needs to perform random access performs cell selection and frequency camping according to the cognitive spectrum information, enters an IDLE state, and then the UE initiates random access, completes random access, enters a CONNECTED state, and starts Communication.

The method according to claim 6, wherein before step 2), the method further comprises: updating the first system message, indicating that all users no longer receive the second system message, if the load rate drops to the threshold .

8. The method according to claim 6, wherein before step 2), the method further comprises: stopping broadcasting the second system message if the load rate drops to the threshold.

9. The method according to claim 6, wherein step 2) comprises:

10. The method according to claim 6, wherein the second system message is a new system message carrying cognitive spectrum information.

The method according to claim 6, wherein the second system message is an existing system message with increased awareness of spectrum information.

The method according to claim 3, wherein the step 2) further comprises determining a priority of the UE initiating the service.

The method according to claim 12, wherein determining the priority of the UE to initiate the service comprises:

When the load ratio of the LTE licensed spectrum is 1, it is determined that the priority of all initiated services is low;

When the load ratio of the LTE licensed spectrum is between the threshold and 1, the priority is determined to be high or low according to the type of service.

The method according to any one of claims 1-3, wherein: step 1) comprises: performing, by the UE, PLMN selection, cell search, cell selection and reselection, and frequency camping on the LTE licensed spectrum, and then entering IDLE status.

15. A system for accessing cognitive frequencies in an LTE system, comprising:

a startup module, configured to perform a boot process on the LTE licensed spectrum by the UE;

The admission control module is configured to schedule, according to the load rate of the LTE licensed spectrum, a UE that needs to perform random access to work in cognitive spectrum or the UE to work at the LTE authorized frequency.