Adaptive link adaptation

• US 20040184482A1
• Filed: 05/09/2003
• Published: 09/23/2004
• Est. Priority Date: 03/19/2003
• Status: Active Grant

• Current Assignee: Beijing Xiaomi Mobile Software Co., Ltd. (Xiaomi Corp.)
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Gronberg, Petri, Vuorinen, Ville
• Granted Patent: US 7,313,737 B2
• Time in Patent Office: Days
• US Class Current: 370/477
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/1614 using bitmaps

Abstract

The invention concerns an adaptive link adaptation method and system for a packet data enabled mobile telecommunication network. Data packets are transferred over one or more radio links, each packet is coded using a given coding scheme. Statistical data including channel quality estimates, information about successfully or unsuccessfully received data packets, and information about the used coding schemes are accumulated. Block error rates for one or more coding schemes are determined based on the accumulated statistical data, each block error rate including a function of coding scheme and channel quality estimate. A coding scheme with the best performance for a current data packet to be transmitted over a given radio link with current channel quality is selected based on the determined block error rates.

Claims

1. An adaptive link adaptation method for a packet data enabled mobile telecommunication network comprising a cell comprising a base station and at least one mobile terminal, the at least one mobile terminals linked to the base station by radio links, at least one radio link having variable channel quality, wherein the method comprises the steps of:

transmitting data packets over at least one radio link, at least one packet coded using a given coding scheme selected from a group of predetermined coding schemes;

accumulating statistical data comprising periodically provided channel quality estimates, periodically provided information about at least one of successfully received data packets and unsuccessfully received data packets, and periodically provided information about the used coding schemes;

determining block error rates for at least one coding scheme based on the accumulated statistical data, at least one block error rate comprising a function of coding scheme and channel quality estimate; and

selecting a coding scheme with a best performance for a current data packet to be transmitted over a given radio link with a current channel quality based on the determined block error rates.

2. The method according to claim 1, wherein said step of accumulating further comprises arranging two tables, a first table comprising entries indicating an amount of successfully received data packets and indexed according to the coding schemes and channel quality estimates;

and a second table comprising entries indicating an amount of unsuccessfully received data packets and indexed according to the coding schemes and channel quality estimates.

3. The method according to claim 2, further comprising resetting a table when at least one entry exceeds a given threshold value.

4. The method according to claim 1, further comprising obtaining the channel quality estimates by measuring channel quality of said radio links during said transferring of data packets over at least one radio link.

5. The method according to claim 1, further comprising providing a packet data enabled mobile telecommunication network comprising a General Packet Radio Service enabled mobile telecommunication network.

6. The method according to claim 1, further comprising a packet data enabled mobile telecommunication network comprising an Edge General Packet Radio Service enabled mobile telecommunication network.

7. The method according to claim 5, further comprising providing the data packets comprising Radio Link Control blocks.

8. The method according to claim 7, further comprising transmitting the data packets in an unacknowledged mode.

9. The method according to claim 7, further comprising transmitting the data packets in an acknowledged mode.

10. The method according to claim 9, further comprising providing the information about the successfully received data packets and the unsuccessfully received data packets by using given bitmaps comprised in Radio Link Control acknowledgement messages, said bitmaps specifying which Radio Link Control blocks have been received successfully or unsuccessfully.

11. The method according to claim 9, further comprising providing the channel quality estimates by using Radio Link Control acknowledgement messages.

12. An adaptive link adaptation system for a packet data enabled mobile telecommunication network comprising a cell comprising a base station and at least one mobile terminal, the at least one mobile terminal linked to the base station by radio links, at least one radio link having variable channel quality, wherein the system comprises:

a transmitter for transmitting data packets over at least one radio link, at least one packet coded using a given coding scheme selected from a group of predetermined coding schemes;

storage means for accumulating statistical data comprising periodically provided channel quality estimates, periodically provided information about at least one of successfully received data packets and unsuccessfully received data packets, and periodically provided information about the used coding schemes; and

a link adapter for determining block error rates for at least one coding scheme based on the accumulated statistical data, at least one block error rate comprising a function of coding scheme and channel quality estimate, and for selecting a coding scheme with a best performance for a current data packet to be transmitted over a given radio link with a current channel quality based on the determined block error rates.

13. The system according to claim 12, wherein the storage means comprise:

a first table comprising entries indicating an amount of successfully received data packets and indexed according to the coding schemes and channel quality estimates; and

a second table comprising entries indicating an amount of unsuccessfully received data packets and indexed according to the coding schemes and channel quality estimates.

14. The system according to claim 13, wherein the storage means further comprise:

resetting means for resetting a table when at least one entry exceeds a given threshold value.

15. The system according to claim 12, wherein the system further comprises:

measuring means for measuring a channel quality of said radio links during said transferring of data packets over the at least one radio link in order to obtain the channel quality estimates to be provided.

16. The system according to claim 12, wherein the transmitter is arranged in connection with a base station.

17. The system according to claim 12, wherein at least one transmitter is arranged in connection with at least one mobile terminal.

18. The system according to claim 15, wherein at least one measuring means is arranged in connection with at least one mobile terminal.

19. The system according to claim 15, wherein the measuring means are arranged in connection with a base station.

20. The system according to claim 12, wherein a link adapter is arranged in connection with a base station.

21. The system according to claim 12, wherein at least one link adapter is arranged in connection with at least one mobile terminal.

22. The system according to claim 12, wherein the storage means is arranged in connection with a base station.

23. The system according to claim 12, wherein at least one storage means is arranged in connection with at least one mobile terminal.

24. The system according to claim 12, wherein a packet data enabled mobile telecommunication network is a General Packet Radio Service enabled mobile telecommunication network.

25. The system according to claim 12, wherein a packet data enabled mobile telecommunication network is an Edge General Packet Service enabled mobile telecommunication network.

26. The system according to claim 24, wherein the data packets are Radio Link Control blocks.

27. The system according to claim 26, wherein the system further comprises:

a Packet Control Unit arranged in connection with a base station, said storage means and a link adapter arranged in connection with said Packet Control Unit.

28. The system according to claim 26, wherein the data packets are arranged to be transmitted in an unacknowledged mode.

29. The system according to claim 26, wherein the data packets are arranged to be transmitted in an acknowledged mode.

30. The system according to claim 29, wherein Radio Link Control acknowledgement messages are arranged to provide the obtained channel quality estimates to the storage means.

31. The system according to claim 29, wherein given bitmaps comprised in Radio Link Control acknowledgement messages are arranged to provide the information about the successfully received data packets and the unsuccessfully received data packets to the storage means, said bitmaps specifying which Radio Link Control blocks have been received successfully or unsuccessfully.