Methods and systems for coding of broadcast messages

• US 6,498,936 B1
• Filed: 01/22/1999
• Issued: 12/24/2002
• Est. Priority Date: 01/22/1999
• Status: Expired due to Term

• Current Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Raith, Alex Krister
• Primary Examiner(s): Le, Thanh Cong
• Assistant Examiner(s): Corsaro, Nick
• Application Number:
  US09/235,469
• Time in Patent Office: 1,432 Days
• Field of Search: 370/312, 370/390, 370/432, 340/744, 455/466, 455/515, 714/752, 714/753, 714/758, 714/779, 714/746, 714/786
• US Class Current: 455/466
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04W 76/40 for selective distribution or broadcast

Abstract

A message is wirelessly broadcast to wireless terminals by error correction coding the message to produce an error correction coded message block, dividing the error correction coded message block into frames and error correction coding the frames to produce error correction coded frames. The error correction coding frames are wirelessly broadcast to the wireless terminals. At the wireless terminals, the frames are received and the frames are error correction decoded to produce error correction decoded frames. The error correction decoded frames are combined into a message block, and the message block is error correction decoded to produce the message. By error correction coding the entire message in addition to error correction coding the frames of the message, long messages may be reliably broadcast and received, notwithstanding fading and other problems in the transmission. Accordingly, a broadcast channel that is designed for short message usage also may be used to reliably transmit long messages. The invention may, for example, be applicable to a TDMA system that includes a Digital Control CHannel (DCCH) having a short message Service Broadcast Control CHannel (S-BCCH) logical channel. The error correction coded frames are placed in the S-BCCH logical channel. The S-BCCH logical channel is then wirelessly broadcast to the radiotelephones in a plurality of TDMA time slots.

Claims

1. A method of wirelessly broadcasting a message to a plurality of wireless terminals comprising the steps of:

error correction coding the message to produce an error correction coded message block;

dividing the error correction coded message block into a plurality of frames;

error detection coding the frames to produce a plurality of error detection coded frames;

error correction coding the error detection coded frames to produce a plurality of error detection and correction coded frames; and

wirelessly broadcasting the plurality of error detection and correction coded frames to the plurality of wireless terminals.

2. A method according to claim 1 wherein the step of error correction coding the message comprises the step of block coding the message and wherein the step of error correction coding the error detection coded frames comprises the step of convolutionally coding the error detection coded frames.

3. A method according to claim 1 wherein the message is a layer 3 message and wherein the frames are layer 2 frames.

4. A method according to claim 1 wherein the step of error correction coding the message comprises the step of block coding the message, wherein the step of error correction coding the error detection coded frames comprises the step of convolutionally coding the error detection coded frames and wherein the step of error detection coding comprises the step of cyclic redundancy checking the frames to produce a plurality of cyclic redundancy checked frames including a cyclic redundancy check value.

5. A method according to claim 1 wherein the step of wirelessly broadcasting comprises the step of wirelessly broadcasting the plurality of error detection and correction coded frames to the plurality of radiotelephones over a broadcast channel.

6. A method according to claim 5 wherein the broadcast channel comprises a plurality of slots.

7. A method according to claim 1 wherein the step of wirelessly broadcasting is repeatedly performed with same content for a predetermined number of cycles, the method further comprising the step of providing at least one of an indication of the predetermined number of cycles and an identification of a current cycle number.

8. A method of wirelessly broadcasting a message to a plurality of wireless terminals comprising the steps of:

error correction coding the message to produce an error correction coded message block;

dividing the error correction coded message block into a plurality of frames;

error correction coding the frames to produce a plurality of error correction coded frames;

providing an indication that the error correction coded message block is error correction coded; and

wirelessly broadcasting the plurality of error correction coded frames and the provided indication to the plurality of wireless terminals.

9. A method according to claim 8 wherein the step of providing an indication comprises the step providing an indication within the message block, that message block is error correction coded.

10. A method according to claim 8 wherein the step of providing an indication comprises the step providing an indication outside the message block, that message block is error correction coded.

11. A method according to claim 8 wherein the step of providing an indication further comprises the step of providing an indication of at least one of a type of error correction coding and an amount of error correction coding in the error correction coded message block.

12. A method of wirelessly receiving a message at a wireless terminal comprising the steps of:

wirelessly receiving a plurality of frames;

error correction decoding the frames to produce a plurality of error correction decoded frames;

error detection decoding the error correction decoded frames to produce a plurality of error detection decoded frames;

providing an indication of the result of the error detection decoding step;

combining the plurality of error detection decoded frames into a message block; and

error correction decoding the message block to produce the message.

13. A method according to claim 12 wherein the step of error correction decoding the message block comprises the step of block decoding the message block and wherein the step of error correction decoding the frames comprises the step of convolutionally decoding the frames.

14. A method according to claim 12 wherein the message block is a layer 3 message block and wherein the frames are layer 2 frames.

15. A method according to claim 12 wherein the step of error correction decoding the message block comprises the step of block decoding the message block, wherein the step of error correction decoding the frames comprises the step of convolutionally decoding the frames and wherein the step of error detection decoding comprises the step of cyclic redundancy checking the frames to produce a plurality of cyclic redundancy checked frames including a cyclic redundancy check value that indicates whether the cyclic redundancy check detected an error.

16. A method according to claim 12 wherein the step of wirelessly receiving comprises the step of wirelessly receiving the plurality of frames over a broadcast channel.

17. A method according to claim 16 wherein the broadcast channel comprises a plurality of slots.

18. A method according to claim 12 wherein the step of wirelessly receiving is repeatedly performed with same content for a predetermined number of cycles, the method further comprising the step of receiving at least one of an indication of the predetermined number of cycles and an identification of a current cycle number and wherein the step of wirelessly receiving is repeatedly performed based upon the received at least one of an indication of the predetermined number of cycles and an identification of a current cycle number.

19. A method according to claim 12 wherein the step of error correction decoding is followed by the step of generating a quality indicator for the wirelessly receiving method.

20. A method according to claim 12 further comprising the step of generating a quality indicator for the wirelessly receiving method based on the indication of the result of the error detection decoding step.

21. A method of wirelessly receiving a message at a wireless terminal comprising the steps of:

wirelessly receiving a plurality of frames;

error correction decoding the frames to produce a plurality of error correction decoded frames;

combining the plurality of error correction decoded frames into a message block; and

error correction decoding the message block to produce the message in response to an indication that the message block is error correction coded.

22. A method according to claim 21 wherein the indication is provided within the message block, that the message block is error correction coded.

23. A method according to claim 21 wherein the indication is provided outside the message block, that the message block is error correction coded.

24. A method according to claim 21 further comprising the step of receiving an indication of at least one of a type of error correction coding and an amount of error correction coding in the message block, and wherein the step of error correction decoding the message block comprises the step of error correction decoding the message block according to the received indication.

25. A method of wirelessly transmitting information comprising the steps of:

error correction coding the message to produce an error correction coded information block;

dividing the error correction coded information block into a plurality of segments;

error detection coding the segments to produce a plurality of error detection coded segments;

error correction coding the error detection coded segments to produce a plurality of error detection and correction coded segments; and

wirelessly transmitting the plurality of error detection and correction coded segments.

26. A method according to claim 25 wherein the step of error correction coding the information comprises the step of block coding the information and wherein the step of error correction coding the error detection coded segments comprises the step of convolutionally coding the error detection coded segments.

27. A method according to claim 25 wherein the step of error correction coding the information comprises the step of block coding the information, wherein the step of error correction coding the error detection coded segments comprises the step of convolutionally coding the error detection coded segments and wherein the step of error detection coding comprises the step of cyclic redundancy checking the segments to produce a plurality of cyclic redundancy checked segments.

28. A method according to claim 25 wherein the step of wirelessly transmitting is repeatedly performed with same content for a predetermined number of cycles, the method further comprising the step of providing at least one of an indication of the predetermined number of cycles and an identification of a current cycle number.

29. A method of wirelessly transmitting information comprising the steps of:

error correction coding the message to produce an error correction coded information block;

dividing the error correction coded information block into a plurality of segments;

error correction coding the segments to produce a plurality of error correction coded segments;

providing an indication that the information block is error correction coded; and

wirelessly transmitting the plurality of error correction coded segments and the provided indication.

30. A method according to claim 29 wherein the step of providing an indication comprises the step providing an indication within the information block that the error correction coded information block is error correction coded.

31. A method according to claim 29 wherein the step of providing an indication comprises the step providing an indication outside the error correction coded information block, that the information block is error correction coded.

32. A method according to claim 29 wherein the step of providing an indication further comprises the step of providing an indication of at least one of a type of error correction coding and an amount of error correction coding in the error correction coded information block.

33. A method of wirelessly receiving information at a wireless terminal comprising the steps of:

wirelessly receiving a plurality of segments;

error correction decoding the segments to produce a plurality of error correction decoded segments;

error detection decoding the error correction decoded segments to produce a plurality of error detection decoded segments;

providing an indication of the result of the error detection decoding step to the combining step;

combining the plurality of error detection decoded segments into an information block; and

error correction decoding the information block to produce the information.

34. A method according to claim 33 wherein the step of error correction decoding the information block comprises the step of block decoding the information block and wherein the step of error correction decoding the segments comprises the step of convolutionally decoding the segments.

35. A method according to claim 33 wherein the step of error correction decoding the information block comprises the step of block decoding the message block, wherein the step of error correction decoding the segments comprises the step of convolutionally decoding the segments and wherein the step of error detection decoding comprises the step of cyclic redundancy checking the segments to produce a plurality of cyclic redundancy checked segments including a cyclic redundancy check value that indicates whether the cyclic redundancy check detected an error.

36. A method according to claim 33 wherein the step of wirelessly receiving is repeatedly performed with same content for a predetermined number of cycles, the method further comprising the step of receiving at least one of an indication of the predetermined number of cycles and an identification of a current cycle number and wherein the step of wirelessly repeating is repeatedly performed based upon the received at least one of an indication of the predetermined number of cycles and an identification of a current cycle number.

37. A method according to claim 33 wherein the step of error correction decoding is followed by the step of generating a quality indicator for the wirelessly receiving method.

38. A method of wirelessly receiving information at a wireless terminal comprising the steps of:

wirelessly receiving a plurality of segments;

error correction decoding the segments to produce a plurality of error correction decoded segments;

combining the plurality of error correction decoded segments into an information block; and

error correction decoding the information block to produce the information in response to an indication that the information block is error correction coded.

39. A method according to claim 38 wherein the indication is provided within the information block, that the information block is error correction coded.

40. A method according to claim 38 wherein the indication is provided outside the information block, that the information block is error correction coded.

41. A method according to claim 38 further comprising the step of receiving an indication of at least one of a type of error correction coding and an amount of error correction coding in the information block, and wherein the step of error correction decoding the information block comprises the step of error correction decoding the information block according to the received indication.

42. A base station that broadcasts a message to a plurality of wireless terminals, the base station comprising:

means for error correction coding the message to produce an error correction coded message block;

means for dividing the error correction coded message block into a plurality of frames;

means for error detection coding the frames to produce a plurality of error detection coded frames;

means for error correction coding the error detection coded frames to produce a plurality of error detection and correction coded frames; and

means for wirelessly broadcasting the plurality of error detection and correction coded frames to the plurality of radiotelephones.

43. A wireless terminal comprising:

means for wirelessly receiving a plurality of frames;

means for error correction decoding the frames to produce a plurality of error correction decoded frames;

means for error detection decoding the error correction decoded frames to produce a plurality of error detection decoded frames;

means for providing an indication of the result of the error detection decoding step to the combining step;

means for combining the plurality of error detection decoded frames into a message block; and

means for error correction decoding the message block to produce a message.