# US 10,313,065 B2 · Method for transmitting a MAC PDU on SL-DCH in a D2D communication system and device therefor

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- Number: US 10,313,065 B2
- Document ID: US10313065B2
- Status: Granted
- Kind: B2
- Application number: 15/542,759
- Filed: 2016-01-21
- Published: 2018-01-11
- Granted: 2019-06-04
- Earliest claimed: 2015-01-28
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Sunyoung Lee; Youngdae Lee; Seungjune Yi; Sunghoon Jung
- Web page: https://patentgrep.com/patent/US10313065B2

## CPC

- H04L 1/1851: {using multiple timers}
- H04L 1/1812: Hybrid protocols; Hybrid automatic repeat request [HARQ]
- H04L 69/324: in the data link layer [OSI layer 2], e.g. HDLC
- H04W 88/02: Terminal devices
- H04W 92/18: between terminal devices
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for transmitting a MAC PDU on SL-DCH in a D2D communication system, the method comprising: configuring a first counter to count a number of transmissions within a transmission period; configuring a second counter to count a number of transmission periods; keeping a Medium Access Control (MAC) Protocol Data Unit (PDU) in a MAC entity until the first counter reaches a first maximum value and the second counter reaches a second maximum value; and transmitting the MAC PDU.

## Claims

### Claim 1

A method for a User Equipment (UE) operating in a wireless communication system, the method comprising:
triggering a new transmission of a Medium Access Control (MAC) Protocol Data Unit (PDU) of a sidelink process for a sidelink Hybrid ARQ (HARQ) entity,
wherein the sidelink HARQ entity is configured with a first counter to count a number of transmissions within a transmission period, and a second counter to count a number of transmission periods; and
transmitting the MAC PDU in a HARQ buffer of the sidelink process until a value of the first counter reaches a first maximum value and a value of the second counter reaches a second maximum value,
wherein the value of the second counter is incremented by 1 each time the MAC PDU is transmitted as a new transmission during a first transmission opportunity of each transmission period,
wherein a value of the first counter is counted only within a last transmission period when the value of the second counter reaches the second maximum value, and
wherein when the value of the first counter reaches the first maximum value and the value of the second counter reaches the second maximum value, the UE flushes the HARQ buffer.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the first counter starts from 0 within the last transmission period.

### Claim 3 (depends on 1)

The method according to claim 1, wherein a value of the first counter is increased by 1 each time the MAC PDU is re-transmitted within the last transmission period.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the second counter is set to 0 when the UE first transmits the MAC PDU.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the MAC PDU is transmitted multiple times across multiple transmission periods until the first counter reaches the first maximum value and the second counter reaches the second maximum value.

### Claim 6

A User Equipment (UE) operating in a wireless communication system, the UE comprising:
a transmitter and a receiver; and
a processor, operatively coupled to the transmitter and the receiver, wherein the processor is configured to:
trigger a new transmission of a Medium Access Control (MAC) Protocol Data Unit (PDU) of a sidelink process for a sidelink Hybrid ARQ (HARQ) entity, wherein the sidelink HARQ entity is configured with a first counter to count a number of transmissions within a transmission period and a second counter to count a number of transmission periods, and
control the transmitter to transmit the MAC PDU in a HARQ buffer of the sidelink process until a value of the first counter reaches the first maximum value and a value of the second counter reaches the second maximum value,
wherein the value of the second counter is incremented by 1, each time the MAC PDU is transmitted as a new transmission during a first transmission opportunity of each transmission period,
wherein a value of the first counter is counted only within a last transmission period when the value of the second counter reaches the second maximum value, and
wherein when the value of the first counter reaches the first maximum value and the value of the second counter reaches the second maximum value, the UE flushes the HARQ buffer.

### Claim 7 (depends on 6)

The UE according to claim 6, wherein the first counter starts from 0 within the last transmission period.

### Claim 8 (depends on 6)

The UE according to claim 6, wherein a value of the first counter is increased by 1 each time the MAC PDU is re-transmitted within the last transmission period.

### Claim 9 (depends on 1)

The UE according to claim 1, wherein second counter is set to 0 when the UE first transmits the MAC PDU.

### Claim 10 (depends on 6)

The UE according to claim 6, wherein the MAC PDU is transmitted multiple times across multiple transmission periods until the first counter reaches the first maximum value and the second counter reaches the second maximum value.

### Claim 11 (depends on 1)

The method according to claim 1, wherein when the value of the second counter does not reach the second maximum value, the UE doesn't count the first counter.

### Claim 12 (depends on 6)

The UE according to claim 6, wherein when the value of the second counter does not reach the second maximum value, the UE doesn't count the first counter.