MTC UE random access method and device

1. A method for a random access of a Machine Type Communication (MTC) User Equipment (UE) the method comprising:

receiving indication information transmitted by a network side, wherein the indication information indicates at least one Coverage Enhancement (CE) level, and a Physical Random Access Channel (PRACH) resource corresponding to the at least one CE level;

selecting one CE level from a CE level of the MTC UE, and the at least one CE level indicated by the network side, and determining a PRACH resource corresponding to the selected CE level; and

initiating a random access over the PRACH resource corresponding to the selected CE level;

wherein selecting one CE level from the CE level of the MTC UE, and the at least one CE level indicated by the network side, and determining the PRACH resource corresponding to the selected CE level comprises:

selecting the CE level of the MTC UE when the CE level of the MTC UE is among the at least one CE level indicated by the network side; and

selecting the PRACH resource corresponding to the selected CE level indicated by the network side according to the CE level of the MTC UE.

2. The method according to claim 1 , wherein the indication information indicates each CE level of the at least one CE level, and a PRACH resource corresponding to each CE level of the at least one CE level.

3. The method according to claim 1 , wherein the indication information indicates a plurality of CE levels, and their corresponding PRACH resources; and

selecting one CE level from the CE level of the MTC UE, and the CE levels indicated by the network side, and determining a PRACH resource corresponding to the selected CE level comprises:

selecting such one of the CE levels indicated by the network side that has a most approximate coverage gain to the CE level of the MTC UE, when the CE level of the MTC UE is not among the CE levels indicated by the network side; and

determining the PRACH resource corresponding to the selected CE level indicated by the network side according to the selected CE level.

4. The method according to claim 1 , wherein the indication information indicates a plurality of CE levels, and their corresponding PRACH resources; and

selecting one CE level from the CE level of the MTC UE, and the CE levels indicated by the network side, and determining the PRACH resource corresponding to the selected CE level comprises:

selecting the CE level of the MTC UE, when the CE level of the MTC UE is not among the CE levels indicated by the network side, and a coverage gain of the CE level of the MTC UE is lower than all the CE levels indicated by the network side; and

determining a PRACH resource corresponding to the CE level of the MTC UE according to a mechanism for selecting a resource of a contention random access.

5. The method according to claim 1 , wherein the indication information indicates a plurality of CE levels, and their corresponding PRACH resources; and

selecting one CE level from the CE level of the MTC UE, and the CE levels indicated by the network side, and determining the PRACH resource corresponding to the selected CE level comprises:

selecting one of the CE levels indicated by the network side, when the CE level of the MTC UE is not among the CE levels indicated by the network side, and a coverage gain of the CE level of the MTC UE is higher than all the CE levels indicated by the network side; and

determining the PRACH resource corresponding to the selected CE level indicated by the network side according to the selected CE level.

6. The method according to claim 1 , wherein the indication information indicates one CE level, and a PRACH resource corresponding to the one CE level; and

selecting one CE level from the CE level of the MTC UE, and the CE level indicated by the network side, and determining a PRACH resource corresponding to the selected CE level comprises:

selecting the CE level indicated by the network side when the one CE level indicated by the network side is not the CE level of the MTC UE; and

determining the PRACH resource corresponding to the selected CE level indicated by the network side according to the selected CE level.

7. The method according to claim 1 , wherein the indication information indicates one CE level, and a PRACH resource corresponding to the one CE level; and

selecting one CE level from the CE level of the MTC UE, and the CE level indicated by the network side, and determining a PRACH resource corresponding to the selected CE level comprises:

selecting the CE level indicated by the network side when the one CE level indicated by the network side is not the CE level of the MTC UE, and a coverage gain of the CE level of the MTC UE is higher than the CE level indicated by the network side; and

determining the PRACH resource corresponding to the selected CE level indicated by the network side according to the selected CE level.

8. The method according to claim 1 , wherein the indication information indicates one CE level, and a PRACH resource corresponding to the one CE level; and

selecting one CE level from the CE level of the MTC UE, and the CE level indicated by the network side, and determining a PRACH resource corresponding to the selected CE level comprises:

selecting the CE level of the MTC UE, when the one CE level indicated by the network side is not the CE level of the MTC UE, and a coverage gain of the CE level of the MTC UE is lower than the CE levels indicated by the network side; and

determining a PRACH resource corresponding to the CE level of the MTC UE according to a mechanism for selecting a resource of a contention random access.

9. The method according to claim 1 , wherein when the random access fails to be initiated over the PRACH resource corresponding to the selected CE level, the method further comprises:

transitioning to a CE level with a coverage gain higher by one level; and

when it is determined that the higher CE level is among the CE levels indicated by the network side, determining the PRACH resource corresponding to the higher CE level indicated by the network side according to the higher CE level, and initiating a contention-free random access over the PRACH resource; otherwise, selecting a PRACH resource according to a mechanism for selecting a resource of a contention random access, and initiating a contention random access.

10. The method according to claim 1 , wherein the indication information indicates the respective CE levels, and their corresponding PRACH resources in any one of the following schemes:

the indication information indicates indexes of the respective CE levels, and their corresponding preamble indexes and PRACH mask indexes;

the indication information indicates combination indexes of combinations of the respective CE levels, and their corresponding PRACH resources, wherein the combination of each CE level, and its corresponding PRACH resource is pre-configured or prescribed in a protocol, and the combination index corresponding to each combination is pre-configured or prescribed in a protocol; and

the indication information indicates indexes of the respective CE levels, and their corresponding PRACH mask indexes, wherein the preamble indexes corresponding to the respective CE levels are pre-configured.

11. A method for triggering a random access of a Machine Type Communication (MTC) User Equipment (UE) by a network side, the method comprising:

transmitting indication information to the MTC UE, wherein the indication information indicates at least one Coverage Enhancement, CE, level, and a Physical Random Access Channel (PRACH) resource corresponding to the at least one CE level; and

receiving a random access initiated by the MTC UE over a PRACH resource corresponding to a selected CE level;

wherein the selected CE level is a CE level of the MTC UE when the CE level of the MTC UE is among the at least one CE level indicated in the indication information, and the PRACH resource corresponding to the selected CE level is indicated in the indication information.

12. The method according to claim 11 , wherein:

the indication information indicates each CE level and its corresponding PRACH resource prescribed in a protocol; or

the indication information indicates a plurality of CE levels and their corresponding PRACH resources prescribed in a protocol; or

the indication information indicates one CE level, and its corresponding PRACH resource prescribed in a protocol.

13. The method according to claim 11 , wherein the indication information indicates the respective CE levels, and their corresponding PRACH resources in any one of the following schemes:

the indication information indicates indexes of the respective CE levels, and their corresponding preamble indexes and PRACH mask indexes;

the indication information indicates combination indexes of combinations of the respective CE levels, and their corresponding PRACH resources, wherein the combination of each CE level, and its corresponding PRACH resource is pre-configured or prescribed in a protocol, and the combination index corresponding to each combination is pre-configured or prescribed in a protocol; and

the indication information indicates indexes of the respective CE levels, and their corresponding PRACH mask indexes, wherein the preamble indexes corresponding to the respective CE levels are pre-configured.

14. A Machine Type Communication (MTC) User Equipment (UE) comprising a memory and at least one processor, wherein the memory is configured to store readable program codes, and the at least one processor is configured to execute the readable program codes to:

receive indication information transmitted by a network side, wherein the indication information indicates at least one Coverage Enhancement, CE, level, and a Physical Random Access Channel (PRACH) resource corresponding to the at least one CE level;

select one CE level from a CE level of the MTC UE, and the at least one CE level indicated by the network side, and determine a PRACH resource corresponding to the selected CE level; and

initiate a random access over the PRACH resource corresponding to the selected CE level;

wherein the at least one processor configured to execute the readable program codes to select one CE level from the CE level of the MTC UE, and the at least one CE level indicated by the network side, and determine the PRACH resource corresponding to the selected CE level is further configured to:

select the CE level of the MTC UE when the CE level of the MTC UE is among the at least one CE level indicated by the network side; and

select the PRACH resource corresponding to the selected CE level indicated by the network side according to the CE level of the MTC UE.

15. The MTC UE according to claim 14 , wherein the indication information indicates each CE level of the at least one CE level, and a PRACH resource corresponding to each CE level of the at least one CE level.

16. The MTC UE according to claim 14 , wherein the indication information indicates one CE level, and a corresponding PRACH resource corresponding to the one CE level; and

the at least one processor is further configured to execute the readable program codes to select one CE level from the CE level of the MTC UE, and the CE level indicated by the network side, and determine the PRACH resource corresponding to the selected CE level is configured to:

select the CE level indicated by the network side when the one CE level indicated by the network side is not the CE level of the MTC UE; and

determine the PRACH resource corresponding to the selected CE level indicated by the network side according to the selected CE level.

17. The MTC UE according to claim 14 , wherein the at least one processor is further configured to execute the readable program codes, when the random access fails to be initiated over the PRACH resource corresponding to the selected CE level, to:

transition to a CE level with a coverage gain higher by one level; and

when it is determined that the higher CE level is among the CE levels indicated by the network side, determine the PRACH resource corresponding to the higher CE level indicated by the network side according to the higher CE level, and initiate a contention-free random access over the PRACH resource; otherwise, select a PRACH resource according to a mechanism for selecting a resource of a contention random access, and to initiate a contention random access.

18. The MTC UE according to claim 14 , wherein the indication information indicates the respective CE levels, and their corresponding PRACH resources in any one of the following schemes:

the indication information indicates indexes of the respective CE levels, and their corresponding preamble indexes and PRACH mask indexes;

the indication information indicates combination indexes of combinations of the respective CE levels, and their corresponding PRACH resources, wherein the combination of each CE level, and its corresponding PRACH resource is pre-configured or prescribed in a protocol, and the combination index corresponding to each combination is pre-configured or prescribed in a protocol; and

the indication information indicates indexes of the respective CE levels, and their corresponding PRACH mask indexes, wherein the preamble indexes corresponding to the respective CE levels are pre-configured.