Data transfer method

• US 8,898,534 B2
• Filed: 10/18/2012
• Issued: 11/25/2014
• Est. Priority Date: 10/04/2006
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hashimoto, Masanori
• Primary Examiner(s): BUTLER, SARAI E
• Application Number:
  US13/654,941
• Publication Number:
  US 20130044584A1
• Time in Patent Office: 768 Days
• Field of Search: 714/748, 714/749
• US Class Current: 714/749
• CPC Class Codes: H04L 1/1642 Formats specially adapted for sequence numbers
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements

Abstract

A data transfer method having a data retransmission function, in which a sending side saves data that was sent in memory, a receiving side uses a transmission confirmation signal to request the sending side to retransmit the data when the data was not properly received, then monitors the elapsed time, and when the data is not retransmitted after the elapsed time has exceeded a set time, uses a transmission confirmation signal again to request that the data be retransmitted, and where in response to that transmission confirmation signal, the sending side retransmits the saved data to the receiving side.

Claims

1. A data retransmit method of a data communication system in which a receiving side, after receiving data, sends a transmission confirmation signal (ACK or NACK) to a sending side indicating whether or not the data was received properly, and the sending side makes reference to the transmission confirmation signal to identify that the receiving side did not proper receive the data and retransmits that data, the data retransmit method comprising:

saving at the sending side, the data sent to the receiving side;

continuing to save the data previously sent to the receiving side even though the sending side confirms that the data previously sent to the receiving side is received properly by a transmission confirmation signal (ACK) corresponding to the data; and

retransmitting the saved data to the receiving side when retransmission of the data is requested from the receiving side.

2. A radio base station (evolved-UTRAN NodeB) for communicating with a terminal (UE), the radio base station comprising a memory and a processor configured to:

store the data (Data[n1]) of RLC (Radio Link Control) layer into the memory;

transmit the data (Data[n1]) to the terminal (UE);

detect a transmission confirmation signal (ACK[n1] or NACK[n1]) from the terminal, the transmission confirmation signal (ACK[n1] or NACK[n1]) indicating whether or not the data (Data[n1]) is received properly by the terminal;

hold the previously transmitted data (Data[n1]) in the memory even after detecting the transmission confirmation signal (ACK[n1]) indicating that the previously transmitted data (Data[n1]) is received properly by the terminal.

3. The radio base station according to claim 2, wherein

the maximum number of items of data that can be transmitted even when the transmission confirmation signal is not received is W,

the sequence number that is attached to the confirmation signal that indicates proper reception is S, and

the processor is configured to delete from the memory data having a sequence number less than S-W.

4. The radio base station according to claim 2, wherein

the processor is configured to:

transmit next data (Data[n2]) of the RLC layer to the terminal in response to detecting the transmission confirmation signal (ACK[n1]) indicating that the data (Data[n1]) is received properly by the terminal;

hold the data (Data[n1]) and the data (Data[n2]) in the memory even after the transmitting the data (Data[n2]) to the terminal in response to detecting the transmission confirmation signal (ACK[n1]).

5. The radio base station according to claim 2, wherein

the processor is configured to:

transmit a HO (Hand Over) command to the terminal when condition to start a handover is satisfied after detecting the transmission confirmation signal (ACK[n1]) indicating that the data (Data[n1]) is received properly by the terminal;

forward the data (Data[n1]) held in the memory to a HO target base station.

6. A terminal (UE) for communicating with a radio base station (evolved-UTRAN NodeB), the terminal comprising a memory and a processor configured to:

store the data (Data[n1]) of RLC (Radio Link Control) layer into the memory;

transmit the data (Data[n1]) to the radio base station;

detect a transmission confirmation signal (ACK[n1] or NACK[n1]) from the radio base station, the transmission confirmation signal (ACK[n1] or NACK[n1]) indicating whether or not the data (Data[n1]) is received properly by the radio base station;

hold the previously transmitted data (Data[n1]) in the memory even after detecting the transmission confirmation signal (ACK[n1]) indicating that the previously transmitted data (Data[n1]) is received properly by the radio base station.

7. The terminal according to claim 6, wherein

the maximum number of items of data that can be transmitted even when the transmission confirmation signal is not received is W,

the sequence number that is attached to the confirmation signal that indicates proper reception is S, and

the processor is configured to delete from the memory data having a sequence number less than S-W.

8. The terminal according to claim 6, wherein

the processor is configured to:

transmit next data (Data[n2]) of the RLC layer to the radio base station in response to detecting the transmission confirmation signal (ACK[n1]) indicating that the data (Data[n1]) is received properly by the radio base station;

hold the data (Data[n1]) and the data (Data[n2]) in the memory even after the transmitting the data (Data[n2]) to the radio base station in response to detecting the transmission confirmation signal (ACK[n1]).

9. The terminal according to claim 6, wherein

the processor is configured to:

receive a HO (Hand Over) command from the radio base station (HO source base station) in response to transmitting a measurement report that satisfies a condition to start handover;

forward to a HO target base station the data (Data[n1]) held in the memory even after detecting the transmission confirmation signal (ACK[n1]) indicating that the data (Data[n1]) is received properly by the HO source base station.