Methods, apparatus and systems for performing a random access procedure in a wireless communication

1. A method performed by a wireless communication node, the method comprising:

receiving, from a wireless communication device, a first message comprising a preamble and a payload for an access to the wireless communication node; and

transmitting, to the wireless communication device, a second message in response to the first message,

wherein the second message is for the wireless communication device to distinguish between a 2-step random access channel (RACH) and a 4-step RACH based on a fixed offset defined in a protocol and added in a calculation of random access radio network temporary identifier (RA-RNTI) for transmitting the second message in the 2-step RACH compared to the 4-step RACH, the fixed offset being a multiple of 14×80×8, and wherein the second message comprises information related to:

an uplink (UL) grant that comprises subsequent resources for subsequent UL transmissions, and a fallback random access response (RAR).

2. The method of claim 1 , further comprising:

configuring a mapping between a first transmission resource for the preamble and a second transmission resource for the payload, wherein the preamble and the payload are received based on the first transmission resource and the second transmission resource, respectively.

3. The method of claim 1 , wherein:

a modulation coding scheme (MCS) is configured for the payload.

4. The method of claim 1 , further comprising:

receiving, from the wireless communication device, a third message, wherein the third message is transmitted, in response to receiving a fallback indication, before a contention resolution timer is started by the wireless communication device.

5. A method performed by a wireless communication device, the method comprising:

transmitting, to a wireless communication node, a first message comprising a preamble and a payload for an access to the wireless communication node; and

receiving, from the wireless communication node, a second message in response to the first message,

wherein the second message is for the wireless communication device to distinguish between a 2-step random access channel (RACH) and a 4-step RACH based on a fixed offset defined in a protocol and added in a calculation of random access radio network temporary identifier (RA-RNTI) for transmitting the second message in the 2-step RACH compared to the 4-step RACH, the fixed offset being a multiple of 14×80×8, and wherein the second message comprises information related to:

an uplink (UL) grant that comprises subsequent resources for subsequent UL transmissions, and a fallback random access response (RAR).

6. The method of claim 5 , further comprising:

determining a configuration of a mapping between a first transmission resource for the preamble and a second transmission resource for the payload, wherein the preamble and the payload are transmitted based on the first transmission resource and the second transmission resource, respectively.

7. The method of claim 5 , wherein:

the wireless communication device is capable of selecting a random access (RA) procedure between a 2-step RACH and a 4-step RACH based on information related to a comparison between a reference signal received power (RSRP) measurement result and a threshold.

8. The method of claim 5 , further comprising:

selecting, by the wireless communication device, the preamble; and

selecting, by the wireless communication device, the payload according to the selected preamble.

9. The method of claim 5 , wherein:

a modulation coding scheme (MCS) is configured for the payload.

10. The method of claim 5 , wherein:

In response to a number of failure transmission attempt of the first message reaching a pre-defined threshold, the wireless communication device is configured as a 4-step RACH, wherein the pre-defined threshold is transmitted to the wireless communication device in a radio resource control (RRC) signaling.

11. The method of claim 5 , further comprising:

in response to receiving a fallback indication, transmitting, by the wireless communication device, a third message and starting a contention resolution timer.

12. A wireless communication node comprising:

a memory storing instructions; and

a processor in communication with the memory, wherein, when the processor executes the instructions, the processor is configured to cause the wireless communication node to:

receive, from a wireless communication device, a first message comprising a preamble and a payload for an access to the wireless communication node, and

transmit, to the wireless communication device, a second message in response to the first message,

wherein the second message is for the wireless communication device to distinguish between a 2-step random access channel (RACH) and a 4-step RACH based on a fixed offset defined in a protocol and added in a calculation of random access radio network temporary identifier (RA-RNTI) for transmitting the second message in the 2-step RACH compared to the 4-step RACH, the fixed offset being a multiple of 14×80×8, and wherein the second message comprises information related to:

an uplink (UL) grant that comprises subsequent resources for subsequent UL transmissions, and a fallback random access response (RAR).

13. The wireless communication node of claim 12 , wherein, when the processor executes the instructions, the processor is configured to further cause the wireless communication node to:

configure a mapping between a first transmission resource for the preamble and a second transmission resource for the payload, wherein the preamble and the payload are received based on the first transmission resource and the second transmission resource, respectively.

14. The wireless communication node of claim 12 , wherein, when the processor executes the instructions, the processor is configured to further cause the wireless communication node to:

receive, from the wireless communication device, a third message, wherein the third message is transmitted, in response to receiving a fallback indication, before a contention resolution timer is started by the wireless communication device.

15. A wireless communication device comprising:

a memory storing instructions; and

a processor in communication with the memory, wherein, when the processor executes the instructions, the processor is configured to cause the wireless communication device to:

transmit, to a wireless communication node, a first message comprising a preamble and a payload for an access to the wireless communication node, and

receive, from the wireless communication node, a second message in response to the first message,

wherein the second message is for the wireless communication device to distinguish between a 2-step random access channel (RACH) and a 4-step RACH based on a fixed offset defined in a protocol and added in a calculation of random access radio network temporary identifier (RA-RNTI) for transmitting the second message in the 2-step RACH compared to the 4-step RACH, the fixed offset being a multiple of 14×80×8, and wherein the second message comprises information related to:

an uplink (UL) grant that comprises subsequent resources for subsequent UL transmissions, and a fallback random access response (RAR).

16. The wireless communication device of claim 15 , wherein, when the processor executes the instructions, the processor is configured to further cause the wireless communication device to:

determine a configuration of a mapping between a first transmission resource for the preamble and a second transmission resource for the payload, wherein the preamble and the payload are transmitted based on the first transmission resource and the second transmission resource, respectively.

17. The wireless communication device of claim 15 , wherein:

In response to a number of failure transmission attempt of the first message reaching a pre-defined threshold, the wireless communication device is configured as a 4-step RACH, wherein the pre-defined threshold is transmitted to the wireless communication device in a radio resource control (RRC) signaling.