Random access method and device

• US 10,334,632 B2
• Filed: 06/23/2016
• Issued: 06/25/2019
• Est. Priority Date: 06/24/2015
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Hwang, Hyun-Yong
• Primary Examiner(s): Nawaz, Asad M
• Assistant Examiner(s): Waqas, Saad A.
• Application Number:
  US15/191,138
• Publication Number:
  US 20160381713A1
• Time in Patent Office: 1,097 Days
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Disclosed is a random access method and device. A terminal generates a random number for a random access, and compares the random number and a setting value. When the random number is included in the setting value, the terminal transmits a preamble for a random access to a base station and attempts a random access.

Claims

1. A random access method of a terminal in a mobile communication system, comprising:

setting information uniquely allocated to the terminal as a seed value;

generating a random number for a random access by using the seed value;

comparing the random number and a setting value; and

transmitting a preamble for a random access to a base station when the random number is included in the setting value,

wherein the setting of the seed value includes;

setting the seed value based on one of a first method for setting a seed value when a terminal is registered, a second method for setting a seed value when a terminal is installed, and a third method for setting a seed value when a connection of a terminal is released; and

assigning priorities to the first method, the second method, and the third method, and setting the seed value based on the corresponding method according to the priorities.

2. The random access method of claim 1, wherein

the setting value is frame information transmitted from the base station,

the comparing includes

comparing frame information transmitted from the base station and the generated random number, and

the transmitting of a preamble to the base station includes

transmitting a preamble for a random access to the base station when the frame information corresponds to the random number.

3. The random access method of claim 1, wherein

the seed value includes one of

an international mobile subscriber identity (IMSI) allocated to a terminal,

an international mobile equipment identity (IMEI) allocated to a terminal, and

a mobile subscriber identification number (MSIN) allocated to a terminal, and

the frame information is a system frame number (SFN).

4. The random access method of claim 1, wherein

the generating of a random number includes

generating a first random number for a random access by using the seed value, and

generating a second random number for a random access by using the seed value,

the comparing of frame information and the generated random number includes

comparing first frame information transmitted by the base station and the first random number, and

comparing second frame information transmitted by the base station and the second random number when the first frame information corresponds to the first random number, and

a preamble for a random access is transmitted to the base station when the second frame information corresponds to the second random number.

5. The random access method of claim 4, wherein

the first frame information is a system frame number (SFN 1), and the second frame information is a sub-frame number (sfn 2),

the first random number is a random value included in a first range, the second random number is a random value included in a second range, and the first range is different from the second range, and

a minimum value and a maximum value of the first range correspond to a minimum value and a maximum value of the SFN 1, respectively, and a minimum value and a maximum value of the second range correspond to a minimum value and a maximum value of the sfn 2, respectively.

6. The random access method of claim 1, wherein

the setting value is a range of available random access channel (RACH) preambles, and

the method further includes allowing the terminal to receive information broadcast by the base station and determining an access barring factor for determining whether to bar an access, and calculating a range of the available RACH preambles by using the access barring factor.

7. The random access method of claim 6, wherein

the generating of a random number includes

generating a random number for the RACH preamble,

the comparing includes

comparing to determine whether the random number is included in the range of available RACH preambles, and

the transmitting of a preamble to the base station includes

transmitting a preamble for a random access to the base station when the random number is included in the range of available RACH preambles.

8. The random access method of claim 7, wherein

the acquiring of an access barring factor further includes

allowing the terminal to receive information broadcast by the base station and acquire an access barring time, and

the transmitting of a preamble to the base station further includes

performing a standby based on the access barring time when the random number is not included in the range of available RACH preambles, and transmitting a preamble for a random access to the base station.

9. The random access method of claim 6, wherein

the terminal belongs to one access class, a value of the access barring factor is changed for each access class, and

a number of preambles belonging to the range of available RACH preambles becomes different according to a value of the access barring factor.

10. A random access method of a terminal in a mobile communication system, comprising:

generating a random number for a random access by setting and using a seed value;

comparing the random number and a setting value; and

transmitting a preamble for a random access to a base station when the random number is included in the setting value,

wherein the setting of the seed value includes;

setting the seed value based on one of a first method for setting a seed value when a terminal is registered, a second method for setting a seed value when a terminal is installed, and a third method for setting a seed value when a connection of a terminal is released; and

assigning priorities to the first method, the second method, and the third method, and setting the seed value based on the corresponding method according to the priorities.

11. The random access method of claim 10, the method further comprising:

generating a first random number for a random access;

generating a second random number for a random access;

comparing a system frame number (SFN

     1) transmitted by a base station and the first random number, and

comparing a sub-frame number (sfn

     2) transmitted by the base station and the second random number when the SFN 1 corresponds to the first random number, and

transmitting a preamble for a random access to the base station when the sfn 2 corresponds to the second random number.

12. The random access method of claim 11, wherein the first random number is a random value included in a first range, the second random number is a random value included in a second range, and the first range is different from the second range, and

a minimum value and a maximum value of the first range correspond to a minimum value and a maximum value of the SFN 1, respectively, and a minimum value and a maximum value of the second range correspond to a minimum value and a maximum value of the sfn 2, respectively.

13. A random access device in a mobile communication system, comprising:

a radio frequency (RF) converter for transmitting/receiving signals through an antenna; and

a processor connected to the RF converter and performing a random access,

wherein the processor is configured to set information uniquely allocated to the terminal as a seed value, generate a random number for a random access by using the seed value, compare the random number and a setting value, and transmit a preamble for a random access to the base station when the random number is included in the setting value,

wherein the setting of the seed value includes;

setting the seed value based on one of a first method for setting a seed value when a terminal is registered, a second method for setting a seed value when a terminal is installed, and a third method for setting a seed value when a connection of a terminal is released; and

assigning priorities to the first method, the second method, and the third method, and setting the seed value based on the corresponding method according to the priorities.

14. The random access device of claim 13, wherein

the setting value represents frame information transmitted from the base station, and

the processor is configured to transmit a preamble for a random access to the base station when the frame information corresponds to the random number.

15. The random access device of claim 14, wherein

the processor is configured to generate a first random number for a random access, generate a second random number for a random access, compare second frame information transmitted by the base station and the second random number when first frame information transmitted by the base station corresponds to the first random number 1, and transmit a preamble for a random access to the base station when the second frame information corresponds to the second random number.

16. The random access device of claim 13, wherein

the setting value represents a range of available random access channel (RACH) preambles acquired by receiving information broadcast from the base station by the terminal, and calculated based on an access barring factor for determining whether to bar an access, and

the processor is configured to generate a random number for RACH preambles, and transmit a preamble for a random access to the base station when the random number is included in the range of available RACH preambles.

17. The random access device of claim 16, wherein

the processor is configured to additionally allow the terminal to receive information broadcast by the base station to acquire an access barring time, perform a standby based on the access barring time when the random number is not included in the range of available RACH preambles, and transmit a preamble for a random access to the base station.

18. The random access device of claim 13, wherein the first frame information is a system frame number (SFN 1), and the second frame information is a sub-frame number (sfn 2),

the first random number is a random value included in a first range, the second random number is a random value included in a second range, and the first range is different from the second range, and

a minimum value and a maximum value of the first range correspond to a minimum value and a maximum value of the SFN 1, respectively, and a minimum value and a maximum value of the second range correspond to a minimum value and a maximum value of the sfn 2, respectively.

19. The random access device of claim 13, wherein the seed value is set based on one of a first method for setting a seed value when a terminal is registered, a second method for setting a seed value when a terminal is installed, and a third method for setting a seed value when a connection of a terminal is released, and

wherein a priority is allocated to the first method, the second method, and the third method, respectively, and the seed value is set based on the corresponding method according to the priority.