CN102111846A - Method for resolving uplink physical random access channel (PRACH) resource congestion in multicarrier system - Google Patents

Abstract

The invention discloses a method for solving uplink PRACH resource congestion in a multi-carrier system. The method adds the center frequency, bandwidth and carrier identification number of other downlink CCs in the same cell to the system information of each downlink CC. The method includes the following steps: step 1, the user terminal scans the channel at a certain frequency interval; step 2, after the user terminal scans a cell, it detects the synchronization signal of the downlink CC in the cell, and after the downlink synchronization, obtains the broadcast control System information in the channel; step 3, the user terminal performs initial access on an uplink CC corresponding to the synchronized downlink CC according to the PRACH resource configuration in the system information. The present invention facilitates the user terminal to camp on other downlink CCs, and then performs initial access on different uplink CCs, and prevents a large number of user terminals from performing initial access on the same uplink CC, resulting in uplink PRACH resource congestion.

Description

A method for solving uplink PRACH resource congestion in multi-carrier system

technical field

The invention belongs to the technical field of mobile communication, and relates to a method for solving uplink PRACH resource congestion in a multi-carrier system.

Background technique

With the development of the mobile industry and the increasing demand for mobile data services, people have higher and higher requirements for the speed and quality of service (Qos) of mobile communications. Therefore, the third generation of mobile communications (3G) has not yet been commercialized on a large scale. Previously, the research and development of the next generation mobile communication system has already started, among which the typical one is the Long Term Evolution (LTE) project launched by the Third Generation Partnership Project (3GPP). The highest spectrum bandwidth that the LTE system can provide is 20MHz (MHz). With the further evolution of the network, LTE-A (Evolved LTE), as an evolution system of LTE, can provide up to 100MHz spectrum bandwidth, support more flexible and higher-quality communication, and have good backward compatibility with LTE. There are multiple Component Carriers (CCs) in the LTE-A system, an LTE user terminal can only work on a certain backward compatible CC, and an LTE-A user terminal can work on multiple CCs at the same time .

When the number of uplink and downlink aggregated carriers is the same, all carriers should be configured to be backward compatible with LTERelease8. Therefore, in the LTE-A system, when the uplink and downlink carriers are symmetrical, each downlink carrier will be configured with a synchronization channel (SCH) and physical broadcast channel (PBCH).

When the carrier frequency of LTE is an integer multiple of 100kHz, for a user terminal that has just been turned on, LTE will perform frequency scanning at intervals of 100kHz in a certain way, and perform primary synchronization signal (PSS) and secondary synchronization when a strong signal is scanned. Synchronization signal (SSS) detection, once the detection is successful, after the downlink synchronization is completed, it starts to receive the system information in the broadcast control channel. The user terminal performs uplink initial access according to the physical random access channel (PRACH) configuration parameters in the system information.

The LTE-A system is a multi-carrier system, and multiple uplink and downlink carriers will be configured. If each downlink carrier is configured with SCH and PBCH, and the user terminal performs channel scanning in a specific way, most user terminals will appear The detection of PSS and SSS is performed only on the same downlink carrier, and the system information in the same broadcast control channel is received, and the PRACH configuration parameters obtained by the user terminal are also the same. Therefore, a large number of user terminals will compete for access on the same uplink carrier corresponding to the downlink carrier receiving the downlink system information according to the same PRACH configuration parameters, resulting in congestion of the PRACH resources of the uplink carrier, while other downlink carriers corresponding to The PRACH resources on the uplink carriers are idle, resulting in unbalanced utilization of the PRACH resources on different uplink carriers.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for solving uplink PRACH resource congestion in a multi-carrier system.

In order to solve the above technical problems, the present invention adopts the following technical solutions.

A method for solving uplink PRACH resource congestion in a multi-carrier system. The method is to add the center frequency, bandwidth and carrier identification number of other downlink CCs belonging to the same cell to the system information of each downlink CC.

As a preferred solution of the present invention, each downlink CC is configured with a synchronization channel and a physical broadcast channel.

As another preferred version of the present invention, the method includes the following steps:

Step 1, the user terminal performs channel scanning at a certain frequency;

Step 2: After the user terminal scans a cell, it detects the synchronization signal of a certain downlink CC in the cell, and obtains the system information in the broadcast control channel after the downlink synchronization;

Step 3, after obtaining the center frequency, bandwidth and carrier identification number of other downlink CCs in the same cell, the user terminal selects a downlink CC to camp on, and receives the system information in the broadcast control channel of the camped downlink CC;

Step 4: The user terminal performs initial access on the uplink CC corresponding to the downlink CC that resides according to the PRACH resource configuration parameters in the system information.

As another preferred solution of the present invention, the frequency interval of channel scanning in step 1 is 100 kHz.

As another preferred solution of the present invention, the synchronization signal detection in step 2 includes primary synchronization signal detection and secondary synchronization signal detection.

As another preferred solution of the present invention, in step 3, the user terminal arbitrarily selects a downlink CC in the same cell to camp on.

As another preferred solution of the present invention, the uplink CC is configured with a PRACH channel.

As another preferred solution of the present invention, the method is applied to a multi-carrier system.

The beneficial effect of the present invention is that it adds the center frequency, bandwidth information and identification number of other downlink CCs of the same cell except the current downlink CC to the system information of each downlink CC, so that user terminals can camp on the same cell Receive different PRACH configuration information on other downlink CCs, and perform initial access on the corresponding different uplink CCs, so as to prevent a large number of user terminals from performing initial access on one uplink CC, resulting in congestion of the uplink PRACH resources.

Description of drawings

FIG. 1 is a schematic diagram of channel scanning of a user terminal.

Detailed ways

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Embodiment one

This embodiment provides a method for solving uplink PRACH resource congestion in a multi-carrier system. The method is to add the center frequency, bandwidth and carrier identification number of other downlink CCs belonging to the same cell to the system information of each downlink CC. Each downlink CC is configured with a synchronization channel and a physical broadcast channel.

The method comprises the steps of:

Step 1, the user terminal performs channel scanning at a certain frequency;

Step 2: After the user terminal scans a cell, it detects the synchronization signal of a certain downlink CC in the cell, and obtains the system information in the broadcast control channel after the downlink synchronization;

Step 3, after obtaining the center frequency, bandwidth and carrier identification number of other downlink CCs in the same cell, the user terminal selects a downlink CC to camp on, and receives the system information in the broadcast control channel of the camped downlink CC;

Step 4: The user terminal performs initial access on the uplink CC corresponding to the downlink CC that resides according to the PRACH resource configuration parameters in the system information.

The frequency interval of channel scanning in step 1 is 100kHz. The synchronization signal detection in step 2 includes primary synchronization signal detection and secondary synchronization signal detection. In step 3, the user terminal arbitrarily selects a downlink CC in the same cell to camp on. The uplink CC is configured with a PRACH channel. The method is applied in a multi-carrier system. The physical broadcast channel is a physical layer channel, the broadcast control channel is a logical channel, and system information is included in the broadcast control channel.

The method of the present invention adds the center frequency, bandwidth information and identification number of other downlink CCs except the current downlink CC to the system information of each downlink CC, so that the user terminal can camp on other downlink CCs to receive different PRACH configurations information, perform initial access on different uplink CCs, thereby preventing a large number of user terminals from performing initial access on one uplink CC, causing congestion of the uplink PRACH resources.

Embodiment two

The LTE-A cell provided in this embodiment has 3 downlink CCs and 3 uplink CCs. As shown in FIG. 1 , each downlink carrier is configured with PSS, SSS and PBCH. According to the method described in Embodiment 1, add the downlink center frequency, bandwidth and identification number of the other two CCs in the same cell except itself to the system information (SystemInformationBlockType2) in the broadcast control channel of each downlink CC.

For LTE user terminals and LTE-A user terminals, cells are searched at frequencies that are integer multiples of 100 KHz. A large number of LTE user terminals are downlink synchronized to downlink CC0#, and then receive system information on the broadcast control channel; LTE-A user terminals know the center of downlink CC1# and downlink CC2# through the system information (SystemInformationBlock Type2) in the broadcast control channel Frequency (d1-CarrierFreq), bandwidth (d1-bandwidth), and identification number (CC-ID). The LTE-A user terminal can choose a downlink CC to camp on, such as downlink CC2#, and receive the PRACH configuration parameters in the broadcast control channel on the downlink CC2#, and then perform initial access on the uplink CC2# corresponding to the downlink CC2#. enter.

The description and application of the invention herein is illustrative and is not intended to limit the scope of the invention to the above-described embodiments. Variations and changes to the embodiments disclosed herein are possible, and substitutions and equivalents for various components of the embodiments are known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be realized in other forms, structures, arrangements, proportions, and with other elements, materials and components without departing from the spirit or essential characteristics of the present invention.

Claims (8)

1. method that solves up PRACH resource congestion in the multicarrier system is characterized in that: increase the centre frequency of other descending CC that belong to same sub-district in the system information of each descending CC, bandwidth and carrier identification number.

2. the method for up PRACH resource congestion in the solution multicarrier system according to claim 1 is characterized in that: equal configuration synchronization channel of each descending CC and Physical Broadcast Channel.

3. the method for up PRACH resource congestion is characterized in that in the solution multicarrier system according to claim 2, may further comprise the steps:

Step 1, user terminal carries out scan channel with certain frequency;

After step 2, user terminal scan a sub-district, the some descending CC in the sub-district is carried out synchronization signal detection, obtain the system information in the Broadcast Control Channel after the down-going synchronous;

Step 3, user terminal is obtaining the centre frequency of other descending CC, and after bandwidth and the carrier identification number, it is resident to select a descending CC to carry out, and receives the system information in the Broadcast Control Channel of resident descending CC;

Step 4, user terminal are initially inserting with the pairing up CC of described resident descending CC according to the PRACH resource distribution parameter in the system information.

4. the method for up PRACH resource congestion in the solution multicarrier system according to claim 3 is characterized in that: the frequency interval of scan channel is 100kHz in the step 1.

5. the method for up PRACH resource congestion in the solution multicarrier system according to claim 3 is characterized in that: synchronization signal detection described in the step 2 comprises that master sync signal detects and auxiliary synchronous signals detects.

6. the method for up PRACH resource congestion in the solution multicarrier system according to claim 3 is characterized in that: user terminal selects a descending CC in the same sub-district to carry out resident arbitrarily in the step 3.

7. the method for up PRACH resource congestion in the solution multicarrier system according to claim 3, it is characterized in that: up CC disposes the PRACH channel.

8. the method for up PRACH resource congestion in the solution multicarrier system according to claim 1, it is characterized in that: described method is applied in the multicarrier system.

Images