WO2010072080A1

WO2010072080A1 - Method for allocating dedicated preamble sequence resources

Info

Publication number: WO2010072080A1
Application number: PCT/CN2009/073699
Authority: WO
Inventors: 张现周; 易鸿锋; 张文英
Original assignee: 中兴通讯股份有限公司
Priority date: 2008-12-26
Filing date: 2009-09-02
Publication date: 2010-07-01
Also published as: CN101765157A

Abstract

The present application discloses a method for allocating the dedicated preamble sequence resources, which includes: a certain dedicated preamble sequence resources are reserved in eNB, the eserved resources are merely allocated to the UE which requests to perform a handover, and for the purpose of transmitting downstream data, the remaining dedicated preamble sequence resources can be allocated to the UE which is out of synchronization. When an UE requests a handover to the cell where the eNB is located, the eNB allocates a reserved dedicated preamble sequence to the UE. When the reserved dedicated preamble sequence resources are exhausted, the eNB allocates the remaining dedicated preamble sequence resources to the UE requesting a handover, wherein the remaining dedicated preamble sequence resources can be allocated to the UE out of synchronization; if the remaining dedicated preamble sequence resources which can be allocated to the UE out of synchronization are exhausted too, allocating the dedicated preamble sequence to the UE requesting a handover would not be performed, and allocating the dedicated preamble sequence resource is failure.

Description

Method for allocating dedicated preamble sequence resources

The present invention relates to Long Term Evolution (LTE) technology, and in particular to a method for allocating dedicated preamble resources.

Background technique

1 is a structural block diagram of an LTE communication system. As shown in FIG. 1, an LTE mobile communication system is composed of an access network and a core network, and the core network includes a Mobility Management Entity (abbreviated as ΜΜΕ) / a service gateway (Service). Gateway (referred to as S-GW) device; the access network includes an eNB (evolutionary NodeB, evolved Node B) device. The eNB and the eNB belonging to the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) of the evolved UMTS (Universal Mobile Telecommunications System) are communicated through the X2 interface through the S1 interface. Communicates with the MME/S-GW in the core network and communicates with the UE (User Equipment) through the Uu interface. The X2 interface is used to exchange information between eNBs.

In order to ensure the continuity of the mobile subscriber service, the user must switch from one serving cell to another. Switching is divided into switching between X2 interfaces and switching across S1 interfaces. The following describes only the switching process across X2 interfaces.

The switching process across the X2 interface, as shown in Figure 2, includes the following steps:

0. The UE context of the source eNB includes a roaming area restriction list of the UE, which is provided during the connection establishment or during the tracking area update process;

1. The source eNB configures the user equipment to start the measurement process, and the measurement may trigger the handover process;

2. The UE reports the measurement report to the source eNB according to the rule of the measurement configuration.

The source eNB sends a handover request message to the target eNB according to the measurement report and the radio resource management reported by the UE, where the necessary information required by the target eNB is carried, such as the X2 signaling context of the UE in the source eNB, and the SI EPC of the UE (Evolution Packet) Core, Evolved Packet Core Network) Signaling Context, Target Cell ID, RRC (Radio Resource Control) The configuration of the access layer, the EPS (Evolution Packet System) bearer context, the physical layer ID of the source cell, etc., the UE X2/UE S1 information enables the target eNB to address the source eNB and the EPC, and the EPS bearer Context includes the necessary addressing information of the wireless network layer and the transport network layer and the Qos (Quality of Service) characteristic information of the EPS bearer;

After receiving the handover request message, the target eNB performs admission control, guarantees QoS, allocates physical resources, and sends a handover request response message to the source eNB, which carries a new C-RNTI (CELL RNTI, cell wireless network identification symbol), and security. Information such as algorithm ID, dedicated preamble sequence (digital signature), and dedicated preamble usage time;

After receiving the handover request response message, the source eNB organizes a handover command (such as an RRC reconfiguration message) according to the message, and sends the message to the UE;

6. The source eNB sends an SN STATUS TRANSFER message to the target eNB, where the PDCP (Packet Data Convergence Protocol) SN receiver status information of the uplink and the PDCP SN transmitter of the downlink are carried. status information;

7. After receiving the handover command, the UE performs the necessary encryption and integrity protection, and uses the new C-RNTI, the dedicated preamble sequence, and the SIB of the target cell (System Information) carried in the message.

Block, system information block), access target cell;

After the UE successfully accesses the target cell, it sends a HANDOVER CONFIRM to the target eNB, indicating that the handover has been completed, and then the target eNB starts to send data to the UE.

9. The target eNB sends a PATH SWITCH message to the MME, notifying the MME that the UE has changed the cell;

10. The MME sends a USER PLANE UPDATE REQUEST message to the gateway S-GW, and the S-GW switches the downlink to the target eNB; and sends the message to the source eNB.

An "end marker" message, notifying the source eNB to release the relevant user plane resource and transport network layer resources, and sending a USER PLANE UPDATE RESPONSE message to the MME;

11. The MME sends a PATH SWITCH Request Ack message to the target eNB.

12. The target eNB receives the PATH SWITCH Request Ack message and sends the UE. The CONTEXT RELEASE message is sent to the source eNB, and the source eNB is notified that the handover has succeeded, and the resource is released;

13. After receiving the UE CONTEXT RELEASE message, the source eNB releases the radio resource and

UE related resources.

As can be seen from the above flow, a dedicated preamble sequence is used for the handover. In another case, the dedicated preamble sequence resource is used, that is, when the UE is in the RRC connection state, the UE is out of synchronization with the network. When there is data in the network to be sent to the UE, the dedicated preamble sequence resource needs to be requested to reacquire the network and the UE. Synchronization.

In the LTE communication system, the preamble sequence resources are divided into two parts: a dedicated preamble sequence and a public preamble sequence. The dedicated preamble sequence is used for handover and uplink out-of-synchronization of the UE and the network; the common preamble sequence can be used for all random access procedures. Since the dedicated preamble sequence group is used for both handover and synchronization of the UE and the network out of synchronization, there may be cases where the dedicated preamble sequence is not available at the time of handover and the handover success rate is reduced. Summary of the invention

To solve the prior art problem, the present invention provides a method for allocating a dedicated preamble sequence resource to solve the problem of using a common preamble sequence due to insufficient dedicated preamble resources, thereby reducing the performance and success rate of handover.

The present invention provides a method for allocating a dedicated preamble sequence resource, including:

Retaining a certain number of dedicated preamble sequence resources in all dedicated preamble sequence resources in the evolved Node B eNB, the resources are only used for the user equipment UE to be allocated for applying for handover; when there is a UE requesting to switch to the When the eNB is located, the eNB allocates a reserved dedicated preamble sequence resource for the UE that requests to handover to the area where the eNB is located.

Further, the step of the eNB for allocating the reserved dedicated preamble sequence resources to the UE that is to be applied to the area where the eNB is located further includes:

If the reserved dedicated preamble sequence resource has been allocated, the eNB allocates a dedicated preamble sequence resource that has not been allocated except the reserved resource to the UE.

Further, the eNB allocates a reservation for the UE that applies for handover to the area where the eNB is located. The steps of the dedicated preamble sequence resource further include:

If the reserved dedicated preamble sequence resource has been allocated, and all dedicated preamble resources except the reserved resource in the eNB have been allocated, the eNB is no longer The UE allocates a dedicated preamble sequence and fails to allocate a dedicated preamble sequence.

Further, the above method may also have the following features:

All dedicated preamble resources except the reserved resource in the eNB are used for the UE to be allocated in the out-of-synchronization state.

Further, the above method further includes:

When the eNB needs to send downlink data to the UE in the out-of-synchronization state, and the dedicated preamble sequence resource to be allocated to the UE in the out-of-synchronization state has also been allocated, the eNB does not allocate the dedicated preamble sequence resource to the UE. , Failed to allocate a dedicated preamble sequence.

Further, the above method further includes:

At intervals, the eNB counts the success rate and/or failure rate of the dedicated preamble sequence resources allocated to the UE applying for handover in the time period;

If the success rate is less than the preset first threshold or the failure rate is greater than the preset second threshold, increase the number of dedicated preamble resources to be allocated to the UE applying for handover and the dedicated preamble resource The total number remains the same;

The eNB then allocates resources for each UE according to the dynamically adjusted number of dedicated preamble sequences.

Further, the above method may also have the following features:

If the success rate is greater than the preset first threshold or the failure rate is less than the preset second threshold, reducing the dedicated preamble resource to be allocated to the UE applying for handover The number and total number of dedicated preamble resources remain unchanged.

Further, the above method further includes:

The eNB statistics the success rate and/or the failure rate of the dedicated preamble sequence resources for the UE in the out-of-synchronization state during the period of time, if the success rate is less than a preset third threshold value or fails. If the rate is greater than the preset fourth threshold, the UE to be allocated to the out-of-synchronization state is added. The number of dedicated preamble sequences and the total number of dedicated preamble resources remain unchanged;

Further, the above method may also have the following features:

If the success rate is greater than the preset third threshold or the failure rate is less than the preset fourth threshold, reducing the number of dedicated preamble resources to be allocated to the UE in the out-of-synchronization state , and the total number of dedicated preamble resources remains the same.

Further, the above method may also have the following features:

The number of the dedicated preamble sequence resources reserved for the first time on the eNB is configured to be synchronized to the eNB after being configured by the network management center or the local management terminal.

By using the method of the present invention, compared with the prior art, since the grouping technical measures for the dedicated preamble sequence resources are taken, the dedicated preamble sequence resources are reserved for handover, so that the user has more opportunities to use the dedicated preamble sequence resources. Random access is performed, which improves the success rate of handover, optimizes network performance, improves user satisfaction, and increases operator revenue. BRIEF abstract

1 is a network structure diagram of an LTE communication system in the prior art;

2 is a flow chart of a cross-over handover across an X2 interface in the prior art;

FIG. 3 is a flowchart of a method for allocating a dedicated preamble sequence resource according to an embodiment of the present invention.

Preferred embodiment of the invention

The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings and embodiments.

The basic idea of the present invention is: Reserve a certain number of dedicated preamble sequence resources on the eNB, the resources are only used for the UE to be allocated for handover, and the remaining dedicated preamble resources are available for allocation to be out of step. The UE in the state to send downlink data. When a UE applies for handover to the area where the eNB is located, the eNB allocates the reserved dedicated preamble sequence resource to the UE. If the reserved dedicated preamble sequence resource has been allocated, and the UE requests the eNB to perform the handover. When switching, the eNB allocates the remaining dedicated preamble resources to be allocated to the UE in the out-of-synchronization state to the UE that performs the handover; if the dedicated preamble resource to be allocated to the UE in the out-of-synchronization state has also been After being allocated, the dedicated preamble sequence is not allocated to the UE that performs handover for the application, and the allocation of the dedicated preamble sequence fails.

When the eNB needs to send downlink data to the UE in the out-of-synchronization state, and the dedicated preamble sequence resource to be allocated to the UE in the out-of-synchronization state has also been allocated, the eNB does not allocate a dedicated preamble sequence to the UE, and allocates The dedicated preamble sequence failed.

In actual use, the dedicated preamble sequence resources to be allocated to the UEs that initiate different requests may be distinguished by grouping all the dedicated preamble sequence resources, for example, the resources may be divided into group A and group B, where The dedicated preamble sequence resource in A is used for the UE to be allocated in the out-of-synchronization state, and the dedicated preamble sequence resource in the group B is used for the UE to be allocated for the handover. According to the above concept, after the resources in the group B have been allocated, the remaining resources in the group A can also be allocated to the UE applying for handover; but the remaining resources in the group B cannot be allocated to the out-of-synchronization state. UE.

In addition, the number of dedicated preamble resources to be allocated to the UE applying for handoff can be dynamically adjusted in the following manner. At intervals, the success rate and/or failure rate of the dedicated preamble sequence resources allocated by the eNB for the UE applying for handover in the time period may be counted to reconfigure the quantity of the dedicated preamble sequence resources of the foregoing parts. If the success rate is less than the preset first threshold or the failure rate is greater than the preset second threshold, the number of dedicated preamble resources to be allocated to the UE applying for handover is increased; otherwise, the number may be reduced. The number of dedicated preamble resources. The total number of dedicated preamble sequence resources after reconfiguration remains unchanged. After the statistics are completed, the original counting result is cleared to zero, and the counting is restarted; and the eNB allocates resources for each UE according to the reconfigured number of dedicated preamble sequence resources.

Of course, the following statistical methods may also be used, that is, the success rate and/or the failure rate of the dedicated preamble sequence resource allocated by the eNB for the UE in the out-of-synchronization state during the period is counted, and the success rate is successful. If the third threshold value is less than the preset third threshold value or the failure rate is greater than the preset fourth threshold value, the number of dedicated preamble sequence resources to be allocated to the UE in the out-of-synchronization state is increased; otherwise, the dedicated preamble sequence may be reduced. The number of resources. The total number of dedicated preamble sequence resources after reconfiguration remains unchanged. The success rate of allocating the dedicated preamble resource to the UE in the out-of-synchronization state is equal to the number of successes of allocating the dedicated preamble resource to the UE in the out-of-synchronization state and the total number of times the dedicated preamble resource is allocated to the UE in the out-of-synchronization state. The rest of the success rate and failure rate are calculated in the same way, and will not be praised here.

In addition, the number of dedicated preamble sequence resources reserved for the first time on the eNB is configured by the network management center or the local management terminal, and then synchronized to the eNB. After a period of time, the eNB allocates a dedicated preamble sequence resource to each UE by using the above-mentioned statistics and using the newly adjusted resource quantity.

In summary, it can be seen that the present invention divides the dedicated preamble sequence resources, one part is allocated to the UE in the out-of-synchronization state, and the other part is used to allocate to the UE that initiates the handover request, and is used in the latter part. When the preamble sequence resource is used up, the resource of the previous part can also be used, which ensures that the dedicated preamble sequence resource available at the time of handover is larger than the dedicated preamble sequence resource required by the UE and the network out of synchronization, and the success rate of the handover is guaranteed; The system performance can be optimized by periodically adjusting the number of resources of the two parts according to the usage of the resources.

It is a matter of course that the invention may be embodied in various other forms and modifications without departing from the spirit and scope of the invention.

Industrial applicability

By dividing the dedicated preamble sequence resources, the present invention ensures that the dedicated preamble sequence resources available at the time of handover are more than the dedicated preamble sequence resources required by the UE and the network out of synchronization, thereby ensuring the success rate of handover; and periodically according to the resources. The usage status adjusts the number of resources in two parts to optimize system performance.

Claims

Claim

A method for allocating a dedicated preamble sequence resource, the method comprising:

A certain number of dedicated preamble sequence resources are reserved in all the dedicated preamble sequence resources in the evolved Node B eNB, and the reserved resources are only used for the user equipment UE to be allocated for applying for handover.

When a UE applies for handover to the area where the eNB is located, the eNB allocates a reserved dedicated preamble sequence resource for the UE that requests to handover to the area where the eNB is located.

2. The method according to claim 1, wherein the step of the eNB to allocate a reserved dedicated preamble sequence resource to the UE that is to be applied to the area where the eNB is located further includes:

If the dedicated preamble resource reserved in the eNB has been allocated, the eNB allocates a dedicated preamble resource that has not been allocated except the reserved resource to the application. Switching to the UE in the area where the eNB is located.

The method of claim 2, wherein the step of the eNB for allocating the reserved dedicated preamble sequence resources to the UE that is to be switched to the area where the eNB is located further includes:

If the dedicated preamble resources reserved in the eNB have been allocated, and all the dedicated preamble resources except the reserved resources have been allocated, the eNB is no longer The UE that applies for handover to the area where the eNB is located allocates a dedicated preamble sequence, and the allocation of the dedicated preamble sequence fails.

4. The method of claim 1, 2 or 3, wherein

All dedicated preamble resources except the reserved resources are used by the eNB to be allocated to UEs in an out-of-synchronization state.

5. The method of claim 4, the method further comprising:

When the eNB needs to send downlink data to the UE in the out-of-synchronization state, and the dedicated preamble sequence resource to be allocated to the UE in the out-of-synchronization state has also been allocated, the eNB is not in the out-of-synchronization state. The UE allocates a dedicated preamble sequence and fails to allocate a dedicated preamble sequence.

6. The method of claim 1, 2 or 3, the method further comprising:

Every once in a while, the eNB counts UEs that are requesting to perform handover in this time period. The success rate and/or failure rate of allocating dedicated preamble resources;

If the success rate is less than the preset first threshold or the failure rate is greater than the preset second threshold, increase the number of dedicated preamble resources to be allocated to the UE applying for handover, and make the dedicated preamble The total number of sequence resources remains the same;

7. The method of claim 6, wherein

If the success rate is greater than the preset first threshold or the failure rate is less than the preset second threshold, the eNB reduces the UE to be allocated to apply for handover. The number of dedicated preamble sequence resources, and the total number of dedicated preamble resources remains unchanged.

8. The method of claim 5, the method further comprising:

The eNB statistics the success rate and/or the failure rate of the dedicated preamble sequence resources for the UE in the out-of-synchronization state during the period of time, if the success rate is less than a preset third threshold value or fails. If the rate is greater than a preset fourth threshold, the number of dedicated preamble resources to be allocated to the UE in the out-of-synchronization state is increased, and the total number of dedicated preamble resources is kept unchanged;

9. The method of claim 8 wherein

If the success rate is greater than the preset third threshold value or the failure rate is less than the preset fourth threshold value, the eNB reduces the to-be-allocated to the UE in the out-of-synchronization state. The number of dedicated preamble sequence resources, and the total number of dedicated preamble sequences remains unchanged.

10. The method of claim 1, 2 or 3, wherein

The number of the dedicated preamble sequence resources reserved for the first time in the eNB is configured by the network management center or the local management terminal, and then synchronized to the eNB.