WO2012075848A1

WO2012075848A1 - Method and device for adjusting preamble initial transmit power of random access channel

Info

Publication number: WO2012075848A1
Application number: PCT/CN2011/079945
Authority: WO
Inventors: 朱永升; 卫建国; 杜高鹏; 张鹏帅
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-12-09
Filing date: 2011-09-21
Publication date: 2012-06-14
Also published as: CN102547952A; CN102547952B

Abstract

The present invention provides a method and a device for adjusting preamble initial transmit power of a random access channel. The method comprises: an eNB serving cell acquiring RACH access information reported by a UE in a current cell and inter-cell interference information from a neighboring cell; according to the RACH access information and the interference information, determining whether a preamble initial transmit power of a random access channel of the current cell satisfies a predetermined condition; and if not, adjusting the preamble initial transmit power of the random access channel of the current cell. The eNB serving cell can, according to the RACH access information reported by the UE in the current cell and interference information of physical resources acquired from the neighboring cell, detect whether the preamble initial transmit power of the random access channel of the current cell is reasonably set, thereby effectively optimizing the initial transmit power of the PRACH preamble, so as to increase the access success rate of the LTE system, decrease the access time delay and the inter-cell interference, and enhance the cell capacity.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a method and an apparatus for adjusting a preamble initial transmit power of a random access channel. BACKGROUND OF THE INVENTION The wireless communication system LTE (Long Term Evolution) is more and more deployed and applied with its open network architecture. With the popularization of wireless communication systems, RACH (Random Access Channel) is used in communication systems. Incoming channel) Unreasonable parameter configuration can have a negative impact on the user experience. If the RACH parameter configuration is unreasonable, the following problems will occur: RACH resource conflicts will cause a large call setup delay, large data recovery delay from the uplink out-of-synchronization state, large handover delay, low call setup success rate, low handover success rate, and reserved The PRACH (Physical Random Access Channel) resource exceeds the system requirement, and the capacity of the system is also reduced. The probability of the RACH Preamble (preamble access) preamble detection is reduced, which may cause the coverage of the cell to be limited. The initial transmit power of the Preamble preamble is too high. At this time, the eNB (Evolved NodeB) can correctly detect the Preamble, but the excessive transmit power will cause large interference to the neighboring area. In order to improve the coverage and capacity of the LTE system and improve the user experience, the RACH configuration parameters of the cells in the network need to be optimized to optimize the processing capability and performance of the network. In the RACH-related configuration parameters, the eNB can easily detect that the configuration of the physical random access channel configuration index PRACH Configuration Index, the random access channel preamble split RACH Preamble Split, and the root sequence index Root Sequence Index is unreasonable, and the eNB is also easy to detect. The initial transmit power to the Preamble is too low. If the initial transmit power of the Preamble is too high, it is difficult to be detected by the eNB. In this case, it is difficult to reasonably optimize the parameter preamblelnitialReceivedTargetPower. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method and apparatus for adjusting a preamble initial transmit power of a random access channel to at least solve the problem that the preamble initial transmit power of the random access channel cannot be reasonably optimized. According to an aspect of the present invention, a method for adjusting a preamble initial transmit power of a random access channel is provided, including: acquiring, by an eNB serving cell, RACH access information reported by a UE in a local cell and interference information between cells in a neighboring cell Determining the preamble of the random access channel of the cell according to the RACH access information and the interference information Whether the initial transmit power meets a predetermined condition; if not, the preamble initial transmit power of the random access channel of the local cell is adjusted. The e B serving cell and the neighboring cell are deployed on different eNBs, and the eNB serving cell acquires the RACH access information reported by the UE in the current cell and the inter-cell interference information from the neighboring cell, including: the eNB serving the cell through the neighboring cell eNB Inter-cell interference information is obtained between the X2 interfaces. The eNB serving cell and the neighboring cell are deployed on the same eNB, and the eNB serving cell acquires the RACH access information reported by the UE in the local cell and the inter-cell interference information from the neighboring cell, and the method includes: the eNB serving cell acquires inter-cell interference information from the eNB. .

The RACH access information reported by the UE is an indication of the number of Preambles that the UE performs when performing random access and whether the UE collides during random access. The interference information of the small interval is the Physical Resource Block (PRB) of the neighboring area. Block) Interference strength. The predetermined condition is: the probability that the UE in the cell successfully accesses is greater than or equal to a predetermined threshold and the PRB interference strength of the neighboring cell is less than a predetermined level. Adjusting the preamble initial transmit power of the random access channel of the cell, including: when the probability of successful access of the UE in the cell is less than a predetermined threshold, increasing the preamble initial transmit power of the random access channel of the cell by one δ Value; when the PRB interference strength of the neighboring cell is greater than a predetermined level, the leading initial transmit power of the random access channel of the cell is lowered by a δ value. According to another aspect of the present invention, an apparatus for adjusting a preamble initial transmit power of a random access channel is provided, including: an acquiring module, configured to acquire, by an eNB serving cell, RACH access information reported by a UE in the current cell, and from a neighboring cell Inter-cell interference information; a determining module, configured to determine, according to the RACH access information and the interference information, whether a preamble initial transmit power of the random access channel of the cell satisfies a predetermined condition; and an adjustment module, configured to be a random access channel to the cell The initial transmit power of the preamble is adjusted. In a case where the eNB serving cell and the neighboring cell are deployed on different eNBs, the receiving module acquires inter-cell interference information by using an X2 interface with the eNB of the neighboring cell. In a case where the eNB serving cell and the neighboring cell are deployed on the same eNB, the receiving module acquires interference information between the cells from the eNB. The predetermined condition is: the probability that the UE in the cell successfully accesses is greater than or equal to a predetermined threshold and the PRB interference strength of the neighboring cell is less than a predetermined level. With the present invention, the e B serving cell can detect whether the PRACH preamblelnitialReceivedTargetPower parameter setting of the current cell is reasonable according to the RACH access information reported by the UE in the current cell and the interference information of the physical resource acquired from the neighboring cell, and the setting is unreasonable. In this case, the parameter is optimized to avoid interference of the PRACH resource to the neighboring cell due to the parameter setting being too high, thereby improving the user experience and system capacity. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 is a flowchart of a method for adjusting a PRACH preamble initial transmission power according to an embodiment of the present invention; FIG. 2 is a schematic diagram of an X2 port LOAD information report according to an embodiment of the present invention; FIG. 4 is a flow chart of optimizing the initial transmit power of the PRACH preamble according to the first embodiment of the present invention; FIG. 5 is a schematic diagram of reporting information of the UE information of the Uu interface according to the embodiment of the present invention; FIG. 6 is a flow chart of optimizing the initial transmit power of the PRACH preamble according to the second embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. 1 is a flowchart of a method for adjusting a PRACH preamble initial transmission power according to an embodiment of the present invention. As shown in FIG. 1, the method includes the following steps: Step S101: An eNB serving cell acquires RACH access information reported by a UE in a local cell, and Inter-cell interference information from the neighboring cell; Step S102, determining whether the preamble initial transmit power of the random access channel of the current cell satisfies a predetermined condition according to the RACH access information and the interference information; Step S103, if no, random to the local cell The preamble initial transmit power of the access channel is adjusted. In this embodiment, the e B serving cell may detect whether the initial transmit power setting of the random access channel of the local cell is set according to the RACH access information reported by the UE in the current cell and the interference information of the physical resource acquired from the neighboring cell. It is reasonable to effectively optimize the initial transmit power of the PRACH preamble to improve the access success rate of the LTE system, reduce the access delay and inter-cell interference, and improve the cell capacity. In the foregoing step S101, when cells between different eNBs are adjacent to each other, the eNB serving cell may acquire inter-cell interference information through an X2 interface with an eNB in the neighboring cell. 2 is a schematic diagram of an X2 port LOAD information report according to an embodiment of the present invention. As shown in FIG. 2, when two adjacent eNB1 and e B2 have an X2 connection, the LOAD INFORMATION function of the X2 port is opened, and the two neighboring areas interact through the message. Uplink 01 (UL Interference Overload Indication) information for each PRB. In the foregoing step S101, if two cells in the neighboring cell are deployed on one eNB, the 01 information between the two cells does not need to be exchanged through X2, and the optimization function can be completed by being acquired internally by the eNB. In the above method, after a UE is successfully accessed, the serving cell instructs the UE to report the RACH information of the access procedure, and the information is combined with the 01 information of the neighboring area to jointly determine the initial transmit power of the PRACH Preamble and the power is too high or Initial transmit power optimization when too low. The predetermined condition in step S102 may be set as follows: the probability that the UE in the cell successfully accesses is greater than or equal to a predetermined threshold and the PRB interference strength of the neighboring cell is less than a predetermined level. The adjustment process in step S103 may be performed by: when the probability of successful access of the UE in the cell is less than a predetermined threshold, the initial transmit power of the random access channel of the cell is increased by one δ; when the PRB of the neighboring cell If the interference strength is greater than the predetermined level, the preamble initial transmission power of the random access channel of the cell is lowered by one. FIG. 3 is a structural block diagram of an apparatus for adjusting an initial transmit power of a PRACH preamble according to an embodiment of the present invention. As shown in FIG. 3, the apparatus includes: an obtaining module 10, a determining module 20, and an adjusting module 30. The obtaining module 10 is configured to acquire, by the eNB serving cell, the RACH access information reported by the UE in the current cell and the inter-cell interference information from the neighboring cell, and the determining module 20 is configured to determine, according to the RACH access information and the interference information, the randomness of the local cell. Whether the preamble initial transmit power of the access channel satisfies a predetermined condition; the adjusting module 30 is configured to adjust a preamble initial transmit power of the random access channel of the cell. In this embodiment, the obtaining module 10 acquires the RACH access information reported by the UE in the current cell and the interference information of the physical resource that is obtained from the neighboring cell, and the determining module 20 determines according to the parameter acquired by the obtaining module 10. Whether the initial transmit power setting of the random access channel of the cell is determined to be reasonable, so that the initial transmit power of the PRACH preamble is optimized to improve the access success rate of the LTE system, reduce the access delay and inter-cell interference, and improve Cell capacity. In the case that the e B serving cell and the neighboring cell are deployed on different e Bs, the receiving module acquires inter-cell interference information through the X2 interface between the eNB and the neighboring cell, and is deployed in the eNB serving cell and the neighboring cell. In the case of the same eNB, the receiving module acquires inter-cell interference information from within the eNB. In the first embodiment, when the initial transmit power of the PRACH is set to be too low, the detection probability of the preamble is reduced, and the random access delay is increased, and the user experience is reduced. This embodiment describes the preamble initial power setting of the random access channel in detail. When the processing flow is too low, as shown in FIG. 4, the following steps are included: Step S501, the RACH optimization function of cell A (cell A) is started. Set the cell cell A related configuration parameters, the cell is successfully established, and services can be provided. Step S502, setting a threshold access delay probability AP(l)=m for the RACH parameter optimization of the local cell, indicating a probability that the UE successfully accesses when the number of Preambles is 1, when the AP(1) of the actual cell A is less than m. The RACH parameter optimization is triggered. In step S503, the UE is attached to the cell A. After the RRC connection is successfully established, the eNB sends a UEInformationRequest message to the UE, and sets rach-ReportReq-r9 in the message to TRUE. Step S504: After receiving the message, the UE determines that the rach-ReportReq-r9 carried in the message is TRUE, and carries the rach-Report-r9 cell in response to the UEInformationResponse (user equipment information response). The message interaction process of steps S503-S504 is as shown in FIG. 4. Step S505: After receiving the response message, the Cell A parses the number of Preambles that are sent by the UE that is carried by the rach-Report-r9 cell to perform random access, and records whether the UE randomly participates in the random access. The cell A sequentially counts the number of Preambles that each UE sends during the random access process, and whether or not contention occurs during the access process. The AP(1) value of the cell A is calculated according to the statistics of the multiple UEs to which the cell A is attached, and the number of Preamble transmissions due to contention is removed. In step S506, it is determined whether the APC1 of the cell A reaches the preset threshold. When the value of the APC1) of the actual cell A is less than the set m, the initial transmit power of the Preamble is considered to be too low, and step S507 is performed. Step S507, triggering the adjustment of the initial transmit power of the Preamble, and raising the value by one. Step S508, after adjusting the initial transmit power of the cell A cell Preamble, continue to monitor the UE random access situation of the cell until the random access probability AP(1) of the cell meets the set threshold m. Embodiment 2 When the preamble initial transmit power of the PRACH is set too high, although the Preamble can be correctly detected, it causes a large interference to the neighboring cell, resulting in a decrease in the capacity of the cell. This embodiment describes in detail the processing flow when the initial power setting of the Preamble is too high. In this embodiment, there are multiple cells adjacent to the cell A, and the neighboring cells are deployed on different eNBs, and the interference information of the neighboring area is reported by the LOAD Information information of the X2 port. As shown in FIG. 6, the following steps are included. Steps S601-S606 are the same as steps S501-S506 in the first embodiment, and are not described in detail herein. Step S607, through the LOAD Information information report of the X2 port, the cell A records the interference of the PRB of the neighboring cell B corresponding to the PRACH resource of the cell, and records the interference of the PRB( _X ) in the last n subframes of the cell B, PRBCx Indicates X PRBs. In this embodiment, the number of PRBs in the cell B that are the same as the PRB time-frequency positions occupied by the PRACH of the cell A are indicated. Step S608, the cell A simultaneously counts interferences of the PRBs of the neighboring cells cell B, cell C, and the like. Step S609, when the value of the AP(1) of the actual cell A satisfies the set m, and the interference of the PRB(x) in the consecutive multiple subframes of the neighboring cells cellB, cell C, etc. is in an overload state, the initial transmit power of the Preamble is considered. If the setting is too high, step S610 is performed. Step S610, triggering adjustment of the initial transmit power of the Preamble, and lowering the value by one. Step S611, after adjusting the initial transmit power of the cell A cell Preamble, continue to monitor the UE random access situation of the cell and the PRB(x) interference of the neighboring cell until the random access probability AP(1) of the cell satisfies the setting. The threshold is m, and the interference of the PRB(x) of the cell B, cell C, etc. in the neighboring cell is in a reasonable range. With the above-mentioned embodiments of the present invention, the inter-cell interference information of the neighboring cell transmitted by the X2 port and the random access procedure information reported by the UE can effectively optimize the initial transmit power of the PRACH preamble to improve the access of the LTE system. Rate, reduce access delay and inter-cell interference, and improve cell capacity. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, thereby Storing them in a storage device is performed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that herein, or they may be separately fabricated into individual integrated circuit modules, or Multiple of these modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for adjusting a preamble initial transmit power of a random access channel, comprising:

The eNB serving cell acquires random access channel RACH access information reported by the UE in the current cell and interference information between cells in the neighboring cell;

Determining, according to the RACH access information and the interference information, whether a preamble initial transmit power of a random access channel of the current cell satisfies a predetermined condition;

If no, the preamble initial transmit power of the random access channel of the cell is adjusted.

The adjustment method according to claim 1, wherein the eNB serving cell and the neighboring cell are deployed on different eNBs, and the eNB serving cell acquires RACH access information reported by the UE in the local cell and the inter-cell from the neighboring cell. Interference information, including:

The eNB serving cell acquires inter-cell interference information through an X2 interface with an eNB in the neighboring cell.

The adjustment method according to claim 1, wherein the eNB serving cell and the neighboring cell are deployed on the same eNB, and the eNB serving cell acquires the RACH access information reported by the UE in the local cell and the inter-cell from the neighboring cell. Interference information, including:

The eNB serving cell acquires interference information between cells from the eNB.

The adjustment method according to any one of claims 1 to 3, wherein the RACH access information reported by the UE is the number of preamble Preambles sent when the UE performs random access, and whether the UE is in random access. An indication of a collision occurs; the interference information between the cells is a PRB interference strength of a physical resource block of the neighboring cell.

The adjustment method according to claim 4, wherein the predetermined condition is: a probability that the UE successfully accesses in the current cell is greater than or equal to a predetermined threshold, and a PRB interference strength of the neighboring cell is less than a predetermined level.

The adjustment method according to claim 5, wherein adjusting the preamble initial transmit power of the random access channel of the cell includes:

When the probability of successful access of the UE in the cell is less than a predetermined threshold, the initial transmit power of the random access channel of the cell is increased by a δ value; When the PRB interference strength of the neighboring cell is greater than a predetermined level, the preamble initial transmission power of the random access channel of the current cell is lowered by a δ value. A device for adjusting a preamble initial transmit power of a random access channel, comprising:

An acquiring module, configured to acquire, by the eNB serving cell, a random access channel RACH access information reported by the UE in the local cell, and interference information between cells in the neighboring cell;

a determining module, configured to determine, according to the RACH access information and the interference information, whether a preamble initial transmit power of a random access channel of the cell satisfies a predetermined condition;

The adjustment module is configured to adjust a preamble initial transmit power of the random access channel of the cell. The adjusting apparatus according to claim 7, wherein, when the eNB serving cell and the neighboring cell are deployed on different eNBs, the receiving module acquires inter-cell access through an X2 interface with an eNB in the neighboring cell. Interference information. The adjusting apparatus according to claim 7, wherein, when the eNB serving cell and the neighboring cell are deployed on the same eNB, the receiving module acquires inter-cell interference information from the eNB. The adjusting device according to any one of claims 7 to 9, wherein the predetermined condition is: a probability that the UE in the cell successfully accesses is greater than or equal to a predetermined threshold, and a physical resource block PRB interference strength of the neighboring cell is less than a predetermined grade.