Packet Indicator for RLC Protocol

• US 20100150062A1
• Filed: 06/09/2009
• Published: 06/17/2010
• Est. Priority Date: 09/12/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bergström, Andreas, Sjögren, Tommy
• Granted Patent: US 8,416,808 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/0084 Formats for payload data
• CPC Class Codes: H04L 1/009 arrangements specific to transmitters

Abstract

In a communication terminal implementing a radio link control (RLC) protocol, error propagation to higher layer protocols is mitigated by use of an additional length indicator, referred to herein as a new packet indicator, in the RLC data blocks to indicate the beginning of a new higher layer packet in addition to a conventional length indicator to indicate the last segment of a higher layer packet. The new packet indicator prevents the LLC data segment at the beginning of an RLC data block from being concatenated with an LLC data segment in the previous data block even when length indicators in the previous data block are not received.

Claims

1. A method of transmitting data packets from a transmitting terminal to a receiving terminal, said method comprising:

encapsulating a data segment for a higher layer data packet in a lower layer data packet;

adding a new packet indicator set to a predetermined value to the lower layer data packet if the data segment comprises the beginning of a new higher layer data packet to indicate the start of a new higher layer data packet; and

adding a length indicator to the lower layer data packet if the data segment comprises the end of a higher layer data packet.

2. The method of claim 1 wherein adding a new packet indicator comprises adding the new packet indicator to the lower layer data packet only when the lower layer data packet begins with a segment of a new higher later data packet.

3. The method of claim 2 further comprising omitting the new packet indicator if the lower layer data packet begins with the last segment of a higher layer data packet.

4. The method of claim 1 wherein the length indicator indicates the length of the data segment.

5. The method of claim 1 wherein the higher layer packets comprise LLC PDUs and the lower layer packets comprise RLC data blocks for transmission over an Enhanced General Packet Radio Service network.

6. The method of claim 5 further comprising transmitting said lower layer packet from a base station to a mobile terminal over a downlink channel.

7. The method of claim 5 further comprising transmitting said lower layer packet from a mobile terminal to a base station over an uplink channel.

8. A communication terminal for a mobile communication network comprising:

a transceiver for transmitting and receiving signals over a wireless communication channel; and

a processor to generate data packets for transmission over the wireless communication channel, the processor configured to;

encapsulate a data segment for a higher layer data packet in a lower layer data packet;

add a new packet indicator set to a predetermined value to the lower layer data packet if the data segment comprises the beginning of a new higher layer data packet to indicate the start of a new higher layer data packet; and

add a length indicator to the lower layer data packet if the data segment comprises the end of a higher layer data packet.

9. The communication terminal of claim 8 wherein the processor is configured to add the new packet indicator to the lower layer data packet only when the lower layer data packet begins with a segment of a new higher later data packet.

10. The communication terminal of claim 9 wherein the processor is configured to omit the new packet indicator if the lower layer data packet begins with the last segment of a higher layer data packet.

11. The communication terminal of claim 8 wherein the length indicator indicates the length of the data segment.

12. The communication terminal of claim 8 wherein the higher layer packets comprise LLC PDUs and the lower layer packets comprise RLC data blocks for transmission over an Enhanced General Packet Radio Service network.

13. The communication terminal of claim 12 configured as a base station for transmitting said lower layer packets over a downlink channel to a mobile terminal.

14. The communication terminal of claim 12 configured as a mobile terminal for transmitting said lower layer packets over an uplink channel to a base station.

15. A method of transmitting data packets from a transmitting terminal to a receiving terminal, said method comprising:

encapsulating a data segment for a higher layer data packet in a lower layer data packet;

adding a length indicator to the lower layer data packet if the data segment comprises the end of a higher layer data packet;

generating a dummy higher layer packet sized to completely fill the lower layer data packet; and

adding a length indicator set to a predetermined value to the next lower layer data packet to indicate the start of a new higher layer packet.

16. A communication terminal for a mobile communication network comprising:

a transceiver for transmitting and receiving signals over a wireless communication channel; and

a processor to generate data packets for transmission over the wireless communication channel, the processor configured to;

encapsulate a data segment for a higher layer data packet in a lower layer data packet;

add a length indicator to the lower layer data packet if the data segment comprises the end of a higher layer data packet;

generate a dummy higher layer packet sized to completely fill the lower layer data packet; and

add a length indicator set to a predetermined value to the next lower layer data packet to indicate the start of a new higher layer packet.