CN1809004A - Method of implementing random access - Google Patents

Abstract

The invention discloses a method for implementing random access, which includes the steps of: setting the signatures selected by the user to occupy different priorities in different access time slots; Access decision processing is performed on each user identified by each signature. The random access realization method of the present invention can reduce network management complexity and system resource overhead on the basis of equal opportunities for each user to access the network.

Description

random access method

technical field

The invention relates to the technical field of mobile communication, in particular to a method for implementing random access in a Wideband Code Division Multiple Access (WCDMA, Wideband Code Division Multiple Access) system.

Background technique

In the WCDMA system, the physical random access channel (PRACH, Physical Random Access Channel) is a physical channel used to carry the random access channel (RACH, Random Access Channel) (where RACH is a logical channel), when the user equipment (UE , User Equipment) needs to access the network side through the PRACH, it is necessary to first select the available signature (Signature) to send the access request information (Preamble) in an access slot (Slot) on the PRACH, and then delay 1.5 to 2.5 After access time slots, determine whether the network allows its access by judging the acquisition indication (AI, Acquisition Indicator) on the acquisition indicator channel (AICH, Acquisition Indicator Channel); if the access request is rejected, the UE delays for 1.5 After accessing the time slot, the access request information is initiated again until the UE reaches its maximum transmission power or the system reaches the preset maximum number of access times; if the access is allowed, the UE sends subsequent Message information.

Since the RACH transmission method is based on the ALOHA method with fast acquisition indication time slots, and in the WCDMA system, the maximum number of users that can be accessed simultaneously in each time slot transmitted on the PRACH is 16. Distinguished by different Signature. Due to the limitation of network access resources, it is generally not possible to simultaneously demodulate the data sent by 16 users in one access slot. Therefore, the base station on the network side needs to select and allow some users to access according to a certain access strategy. , where the access strategy selected by the base station on the network side should ensure the principle of fair access among different users to the greatest extent.

In the prior art, the base station on the network side generally selects two access strategies to judge the access of different users, so as to control the number of access users to not exceed the access resources of the network system:

The first is to process the Signatures representing 16 users in each access slot in order on the base station side. For example, Signature0~Signature15 represent 16 users respectively, then process Signature0, Signature1... in order, and combine the system Access resources are used to complete the access decision for each user. The processing principle is that the user represented by the Signature that is processed first is allowed to access first.

It can be seen that in the first access strategy, since Signature0~Signature15 respectively representing 16 users in each access slot are processed in turn, this will inevitably lead to the processing priority of Signature0 being higher than that of Signature1, and the processing priority of Signature1 The processing priority of Signature14 is higher than that of Signature15, so that users represented by Signature15 and others cannot access the network with equal opportunities with other users, and it cannot reflect the fairness among different users. access principle.

The second is to construct a Signature processing table on the base station side, and change the order of the table lookup every time when access judgment processing is performed between users in different access time slots, and combine system access resources to complete each The processing principle of the user's access judgment is also that the user represented by the Signature that is processed first is allowed to access first. This access strategy can ensure that the sequence of Signatures processed in each access slot will change, so to a certain extent, each user can access the network with an equal opportunity.

However, in the above-mentioned second access strategy, since there may be 16 Signatures representing 16 users in each access slot in PRACH at the same time, and it is necessary to ensure that each access slot should be changed as much as possible. The order of table lookup, so the management of the Signature processing table is relatively complex, and the overhead of occupying system resources is also relatively large.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for implementing random access, so that each user can access the network with an equal opportunity, and reduce network management complexity and system resource overhead.

In order to solve the above problems, the present invention proposes a method for realizing random access, comprising steps:

Set the signatures selected by the user to occupy different priorities in different access slots;

Access decision processing is performed on each user identified by each signature according to the priority sequence of each signature in each access slot.

Wherein each access slot allows access with different signatures for identifying 16 users, and each access slot is set with 16 priorities.

The signatures selected by the user can be set to have different priorities in different access slots by setting the following matrix:

00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15

01 00 03 02 05 04 07 06 09 08 11 10 13 12 15 14

02 03 00 01 06 07 04 05 10 11 08 09 14 15 12 13

03 02 01 00 07 06 05 04 11 10 09 08 15 14 13 12

04 05 06 07 00 01 02 03 12 13 14 15 08 09 10 11

05 04 07 06 01 00 03 02 13 12 15 14 09 08 11 10

06 07 04 05 02 03 00 01 14 15 12 13 10 11 08 09

07 06 05 04 03 02 01 00 15 14 13 12 11 10 09 08

08 09 10 11 12 13 14 15 00 01 02 03 04 05 06 07

09 08 11 10 13 12 15 14 01 00 03 02 05 04 07 06

10 11 08 09 14 15 12 13 02 03 00 01 06 07 04 05

11 10 09 08 15 14 13 12 03 02 01 00 07 06 05 04

12 13 14 15 08 09 10 11 04 05 06 07 00 01 02 03

13 12 15 14 09 08 11 10 05 04 07 06 01 00 03 02

14 15 12 13 10 11 08 09 06 07 04 05 02 03 00 01

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

Each row of elements 00 to 15 in the matrix is respectively used to identify the signatures of 16 users in one access time slot; the order of each row of elements indicates the priority order of different signatures.

The process of selecting different labels in the access slots identified by each row of the matrix for processing includes steps:

(1) Initialize the access slot number identified by the first row of the matrix to be zero;

(2) Initialize the sequence number of the label signature to be processed in this row to be zero;

(3) The tag sig to be processed this time is equal to the sequence number or the access slot number;

(4) Add 1 to the sequence number, and judge whether the processed sequence number is less than 16, if so, return to step (3); otherwise

(5) judging whether the next row of the matrix exists, if yes, adding 1 to the access slot, so as to go to the access slot identified by the next row of the matrix, and then return to the execution step ( 2); otherwise, return to step (1).

The method for implementing random access in the present invention sets the signatures selected by the user to occupy different priorities in different access time slots; Each user identified by each signature performs access judgment processing, so that each user can enjoy an equal priority access order within a period of time, which well reflects the principle of fair access among different users, and the network management is complex The degree is low, and the overhead of occupying system resources is small, which is conducive to improving the random access performance of the network system.

Description of drawings

Fig. 1 is a flow chart of main realization principles of the random access realization method of the present invention.

Fig. 2 is a schematic diagram of the process of selecting different labels Signature in the access slots identified by each row in the matrix based on the constructed 16×16 matrix of the random access implementation method of the present invention for processing.

Detailed ways

It has been discussed in the above prior art that on the base station side of the mobile communication network, due to the limitation of limited access resources, it is generally unable to support simultaneous data sent by 16 users identified by 16 different signatures in one access time slot. Demodulation; therefore, under the condition that system access resources allow, it is necessary to reflect the principle of fair access among users. The implementation method of random access in the present invention is based on the above principles, and provides a processing method based on table lookup, which can not only reduce the management complexity of the network side, but also occupy less overhead of system resources. On the basis of , the random access performance of the network system can be improved to a greater extent.

The specific implementation process of the method for realizing random access of the present invention will be described in detail below in conjunction with each drawing. Please refer to Fig. 1, which is a flowchart of the main realization principle of the random access realization method of the present invention, and its main realization process is as follows:

Step S10, when setting the user to access the network side through the PRACH, the signature Signature selected by the user occupies different priorities in different access slots Slot; wherein in the WCDMA system, each access slot Slot allows There are 16 different Signature accesses used to identify 16 users respectively, and 16 priorities are set for each Signature accessed in each Slot.

Since there are 16 different Signatures in each Slot to identify 16 different users, it is possible to set a 16×16 matrix to set the Signature selected by the user to occupy different priorities in different Slots. The 16x16 matrix is as follows:

00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15

01 00 03 02 05 04 07 06 09 08 11 10 13 12 15 14

02 03 00 01 06 07 04 05 10 11 08 09 14 15 12 13

03 02 01 00 07 06 05 04 11 10 09 08 15 14 13 12

04 05 06 07 00 01 02 03 12 13 14 15 08 09 10 11

05 04 07 06 01 00 03 02 13 12 15 14 09 08 11 10

06 07 04 05 02 03 00 01 14 15 12 13 10 11 08 09

07 06 05 04 03 02 01 00 15 14 13 12 11 10 09 08

08 09 10 11 12 13 14 15 00 01 02 03 04 05 06 07

09 08 11 10 13 12 15 14 01 00 03 02 05 04 07 06

10 11 08 09 14 15 12 13 02 03 00 01 06 07 04 05

11 10 09 08 15 14 13 12 03 02 01 00 07 06 05 04

12 13 14 15 08 09 10 11 04 05 06 07 00 01 02 03

13 12 15 14 09 08 11 10 05 04 07 06 01 00 03 02

14 15 12 13 10 11 08 09 06 07 04 05 02 03 00 01

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

The order in which each Signature is processed by each access slot Slot corresponds to a row of the matrix, and the polling method is used between access slots, that is, the first access slot corresponds to the first row of the matrix , the second access slot corresponds to the second row of the matrix ... and so on. The constraints for setting this matrix are:

The 00-15 arrays in each row represent Signature0 to Signature15 respectively; the order of the arrays in each row corresponds to the processing order between different Signatures in an access slot.

The 00-15 arrays in each column represent Signature0 to Signature15 respectively; the first Signature on the left of each column indicates the first Signature to be processed in the current access slot, and the subsequent Signatures to be processed in turn.

Looking at each row of the matrix, between any two arrays a and b, there are 8 rows of array a appearing on the left of array b, and 8 rows of array b appearing on the left of array a.

Therefore, in this constructed matrix, the rows correspond to different access slots (16 rows represent a cycle period of 16), and the columns correspond to the processing order of different Signatures in the current access slot, so it can reflect the maximum The principle of fair access (the so-called fair access principle means that the order in which each Signature representing each user is processed is relatively fair, and within a period of time, and under the same conditions, the Signature used to identify the same user is in different access Each time slot will experience various access processing priorities).

Step S20, perform access decision processing on each user identified by each Signature according to the priority order of each Signature in each access slot above, so as to limit the access of subsequent users when the system access resource limit is reached .

Please refer to FIG. 2, which is a schematic diagram of the process of selecting different labels Signature in the access slots identified by each row in the matrix based on the constructed 16×16 matrix of the random access implementation method of the present invention; wherein the specific The process is as follows:

Step S100, initializing the access slot number identified by the first row of the matrix to zero;

Step S110, initialize the serial number of the label signature to be processed in this row to be zero;

Step S120, the label sig to be processed this time is equal to the sequence number XOR the access slot number;

Step S130, adding 1 to the sequence number;

Step S140, judging whether the sequence number after processing is less than 16, if yes, return to step S120; otherwise, execute step S150;

Step S150, judging whether the next row of the above matrix exists, if yes, execute step S160; otherwise return to execute step S100;

Step S160, add 1 to the access slot number, so as to go to the access slot identified in the next row of the matrix, and then return to execute S110.

The above process of selecting each Signature is reflected in the specific algorithm as follows:

1. Initialize the access slot number to 0;

2. When performing access decision processing for each Signature used to identify each user in each access slot, calculate the current access slot number (00...15, the period is 16);

Wherein the current access slot number=(access slot number ++) modulus 16; (because in the above matrix, the access slot is periodic with 16, so modulo 16);

3. When processing each Signature in the same access slot, execute:

for(sig=0; sig<16; sig++)

{

Signature=sig XOR access processing time slot number to be processed this time;

…

}

Also in the above access strategy, in each access time slot, it is also based on the principle of user access based on the previously processed Signature identification, so it can be ensured that the Signature identifying the same user is processed in different access time slots The order of is different, which can well reflect the principle of ensuring fair access of each user in the PRACH channel with an extremely simple algorithm.

It should also be noted here that although the preferred embodiment of the present invention has been described above, multiple transformations and changes can also be made to the above-mentioned disclosed solutions, as long as they do not depart from the scope defined by the claims of the present invention, they all fall within the scope of the present invention. within the scope of protection.

Claims (4)

1, a kind of implementation method that inserts at random is characterized in that, comprises step:

Set the user-selected signature of getting and in different access slots, occupy different priority respectively;

Priority orders according to each signature in each access slot inserts decision process to each user who is identified by each signature.

2, the implementation method that inserts at random as claimed in claim 1 is characterized in that, allows the difference signature that is respectively applied for 16 users of sign in described each access slot and inserts, and be provided with 16 priority in each access slot.

3, the implementation method that inserts at random as claimed in claim 1 or 2 is characterized in that, realizes that by following matrix is set the user-selected signature of getting of setting occupies different priority respectively in different access slots:

00?01?02?03?04?05?06?07?08?09?10?11?12?13?14?15

01?00?03?02?05?04?07?06?09?08?11?10?13?12?15?14

02?03?00?01?06?07?04?05?10?11?08?09?14?15?12?13

03?02?01?00?07?06?05?04?11?10?09?08?15?14?13?12

04?05?06?07?00?01?02?03?12?13?14?15?08?09?10?11

05?04?07?06?01?00?03?02?13?12?15?14?09?08?11?10

06?07?04?05?02?03?00?01?14?15?12?13?10?11?08?09

07?06?05?04?03?02?01?00?15?14?13?12?11?10?09?08

08?09?10?11?12?13?14?15?00?01?02?03?04?05?06?07

09?08?11?10?13?12?15?14?01?00?03?02?05?04?07?06

10?11?08?09?14?15?12?13?02?03?00?01?06?07?04?05

11?10?09?08?15?14?13?12?03?02?01?00?07?06?05?04

12?13?14?15?08?09?10?11?04?05?06?07?00?01?02?03

13?12?15?14?09?08?11?10?05?04?07?06?01?00?03?02

14?15?12?13?10?11?08?09?06?07?04?05?02?03?00?01

15?14?13?12?11?10?09?08?07?06?05?04?03?02?01?00

Wherein every row element 00～15 is respectively applied for the signature that identifies 16 users in the access slot in this matrix; The front and back of every row element are represented the priority orders between the different signatures in proper order.

4, the implementation method that inserts at random as claimed in claim 3 is characterized in that, chooses the different labels in the access slot that the every row of described matrix identified to comprise step with the process of handling:

(1) access slot that identified of the described matrix of initialization first row number is zero;

(2) serial number of label signature to be processed is zero in this row of initialization;

(3) this label sig that should handle equals the described access slot of described serial number XOR number;

(4) described serial number is added up 1 handle, and whether the serial number after the judgment processing is less than 16, if return execution in step (3); Otherwise

(5) whether the next line of judging described matrix exists, if, described access slot added up 1 handle, to go to the access slot that next line was identified of described matrix, return execution in step (2) then; Otherwise return execution in step (1).

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