# US 10,455,531 B2 · Method and apparatus for identifying uplink timing advance in a wireless communication system

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- Number: US 10,455,531 B2
- Document ID: US10455531B2
- Status: Granted
- Kind: B2
- Application number: 15/797,483
- Filed: 2017-10-30
- Published: 2018-05-03
- Granted: 2019-10-22
- Earliest claimed: 2016-11-01
- Assignees: ASUSTeK COMPUTER INC.
- Applicants: ASUSTek Computer Inc.
- Inventors: Hsin-Hsi Tsai; Yu-Hsuan Guo; Richard Lee-Chee Kuo
- Web page: https://patentgrep.com/patent/US10455531B2

## CPC

- H04W 56/0005: {synchronizing of arrival of multiple uplinks}
- H04W 56/00: Synchronisation arrangements
- H04W 56/0045: {compensating for timing error by altering transmission time}
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04W 74/0836: with 2-step access
- H04W 74/0838: using contention-free random access [CFRA]
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A method and apparatus are disclosed from the perspective of a UE. In one embodiment, the method includes maintaining a first timing advance for a cell, wherein the first timing advance is associated with a first identifier. The method further includes performing a random access procedure in the cell. The method also includes receiving an initial value of a second timing advance for the cell via a random access response of the random access procedure. In addition, the method includes receiving a second identifier to associate with the second timing advance. Furthermore, the method includes maintaining the first timing advance and the second timing advance for the cell.

## Claims

### Claim 1

A method for a UE (User Equipment) to maintain timing advances for multiple network nodes in a cell of a wireless communication system, comprising:
maintaining a first timing advance for the cell, wherein the first timing advance is associated with a first identifier;
performing a random access procedure in the cell;
receiving an initial value of a second timing advance for the cell via a random access response of the random access procedure;
receiving a second identifier to associate with the second timing advance; and
adjusting the first timing advance if a first timing advance command with the first identifier is received and adjusting the second timing advance if a second timing advance command with the second identifier is received.

### Claim 2 (depends on 1)

The method of claim 1, wherein the second identifier is received together with the initial value for the second timing advance.

### Claim 3 (depends on 1)

The method of claim 1, wherein the second identifier is received via a contention resolution of the random access procedure.

### Claim 4 (depends on 1)

The method of claim 1, wherein the second identifier is received via a signaling used to trigger the random access procedure.

### Claim 5 (depends on 4)

The method of claim 4, wherein the signaling indicates a dedicated preamble.

### Claim 6 (depends on 1)

The method of claim 1, wherein the second identifier is received via a signaling used to add at least one serving beam.

### Claim 7 (depends on 1)

The method of claim 1, wherein the first timing advance is used for at least a first network node of the multiple network nodes in the cell, and the second timing advance is used for at least a second network node of the multiple network nodes in the cell.

### Claim 8 (depends on 1)

The method of claim 1, wherein the UE applies the first timing advance to adjust timing of a first UL transmission associated with the first timing advance.

### Claim 9 (depends on 1)

The method of claim 1, wherein the UE applies the second timing advance to adjust timing of a second UL transmission associated with the second timing advance.

### Claim 10

A User Equipment (UE) to maintain timing advances for multiple network nodes in a cell of a wireless communication system, comprising:
a control circuit;
a processor installed in the control circuit; and
a memory installed in the control circuit and operatively coupled to the processor;
wherein the processor is configured to execute a program code stored in the memory to:
maintain a first timing advance for the cell, wherein the first timing advance is associated with a first identifier;
perform a random access procedure in the cell;
receive an initial value of a second timing advance for the cell via a random access response of the random access procedure;
receive a second identifier to associate with the second timing advance; and
adjust the first timing advance if a first timing advance command with the first identifier is received and adjust the second timing advance if a second timing advance command with the second identifier is received.

### Claim 11 (depends on 10)

The UE of claim 10, wherein the second identifier is received together with the initial value for the second timing advance.

### Claim 12 (depends on 10)

The UE of claim 10, wherein the second identifier is received via a contention resolution of the random access procedure.

### Claim 13 (depends on 10)

The UE of claim 10, wherein the second identifier is received via a signaling used to trigger the random access procedure.

### Claim 14 (depends on 13)

The UE of claim 13, wherein the signaling indicates a dedicated preamble.

### Claim 15 (depends on 10)

The UE of claim 10, wherein the second identifier is received via a signaling used to add at least one serving beam.

### Claim 16 (depends on 10)

The UE of claim 10, wherein the first timing advance is used for at least a first network node of the multiple network nodes in the cell, and the second timing advance is used for at least a second network node of the multiple network nodes in the cell.

### Claim 17 (depends on 10)

The UE of claim 10, wherein the processor is further configured to execute the program code stored in the memory to:
apply the first timing advance to adjust timing of a first UL transmission associated with the first timing advance.

### Claim 18 (depends on 10)

The UE of claim 10, wherein the processor is further configured to execute the program code stored in the memory to:
apply the second timing advance to adjust timing of a second UL transmission associated with the second timing advance.