Receiver for time division multiplex system without explicit time slot assignment
(19)AUSTRALIAN PATENT OFFICE (54) Title Receiver for time division multiplex systemwithout explicit time slot assignment (51)6 International Patent Classification(s) H04B 007/212 (21) Application No: 2003299678 (22) Application Date: 2003.10.06 (87) WIPO No: WO04/034618 (30) Priority Data (31) Number (32) Date 10/266,079 2002.10.07 (33) Country US 200510277 (43) Publication Date : 2004 .05.04 (43) Publication Journal Date : 2004 .06.03 (71) Applicant(s) IPR LICENSING, INC. (72) Inventor(s) Rouphael, Antoinc J.; Nelson, George Rod ney Jr.; Johnson, Kevin P. (-1-1) Application NoAU2003299678 A8(19)AUSTRALIAN PATENT OFFICE (54) Title Receiver for time division multiplex systemwithout explicit time slot assignment (51)6 International Patent Classification(s) H04B 007/212 (21) Application No: 2003299678 (22) Application Date: 2003.10.06 (87) WIPO No: WO04/034618 (30) Priority Data (31) Number (32) Date 10/266,079 2002.10.07 (33) Country US 200510277 (43) Publication Date : 2004 .05.04 (43) Publication Journal Date : 2004 .06.03 (71) Applicant(s) IPR LICENSING, INC. (72) Inventor(s) Rouphael, Antoinc J.; Nelson, George Rod ney Jr.; Johnson, Kevin P.-1- A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. However, no specific information regarding the assignment of time slots need be communicated to the receivers. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the signals in such a manner that only the receiver with the correct cover sequence assigned to a particular connection will successfully decode the data associated with that connection. Data frames that fail the forward error correction process are discarded, and only those frames which are successfully decoded are passed up to a higher layer. The occurrence of an erroneously received frame is not necessarily always reported to the transmit side of the connection; only a packet level error indication is made. In this way, information containing time slot assignment need not be communicated between the transmitter and receiver, and yet data will be correctly received. CLAIMS What is claimed is: 1. A method for communication in a time division multiplex system wherein access to a shared physical channel is assigned on a demand basis by allocating timeslots to provide multiple connections between transmitters and receivers, each given connection of the multiple connections having a given transmitter and receiver, the method comprising: at a given transmitter, allocating at least one time slot to carry forward link packet data on a forward link channel; dividing a given packet into at least one frame; encoding each of the at least one frames with a forward error correction code; further cover sequence encoding each of the at least one frames with a cover sequence unique to the given connection between the transmitter and the given receiver;STDC0615 combining cover sequence encoded frames from the given transmitter with at least one cover sequence encoded frame from another transmitter; and at the given receiver, performing a cover sequence decoding process by combining a received signal with a cover sequence unique to the given receiver of the given connection, to provide a candidate frame; and decoding the candidate frame using a forward error correction decoding process, the cover sequence encoding operable to be decoded only by the cover sequence unique to the given receiver corresponding to the given connection. <Desc/Clms Page number 15> 2. A method as in Claim 1 additionally comprising: if the forward error correction decoding process indicates a correctly received candidate frame, then forwarding the candidate frame to a packet assembler process in a higher level communication layer.
3. A method as in Claim 1 additionally comprising: if the forward error correction decoding process indicates a correctly received candidate frame, then passing a positive indication of having correctly received a candidate frame to a higher level communication layer.
4. A method as in Claim 3 wherein the positive indication to the higher communication layer is given in the frame itself.
5. A method as in Claim 1 additionally comprising: if the forward error correction decoding process indicates an incorrectly received candidate frame, then not passing a positive indication of having correctly received a candidate frame to a higher level communication layer.
6. A method as in claim 2 additionally comprising: if the packet assembler process detects a frame error, then passing an indication to a still higher communication layer.
7. A method as in claim 6 wherein the frame error is a missing frame.
8. A method as in claim 6 wherein the frame error is an extra frame.
9. A method as in claim 6 wherein the frame error is an out of sequence frame.
10. A method as in claim 6 wherein retransmission of the erroneous frame is requested. <Desc/Clms Page number 16> 11. A method as in claim 2 wherein the packet assembler discards the packet upon a frame error.
12. A method as in Claim 1 wherein the shared physical channel is a wireless channel.
13. A method as in Claim 1 wherein a separate shared access channel provides information to the receiver to decode the frame.
14. A method as in Claim 13 wherein the information to decode the frame is a control message directed from the given transmitter to the given receiver.
15. A method as in Claim 13 wherein the information provided to decode the frame is an indication of the cover sequence.
16. A method as in Claim 1 wherein the cover sequence is provided to the given receiver during a system configuration phase.
17. A method as in Claim 1 wherein the cover sequence is provided to the given receiver in response to a channel allocation request.
18. A method as in Claim 1 wherein the cover sequence is a long pseudorandom noise (PN) code.
19. A method as in Claim 1 wherein the cover sequence is not a long psuedorandom noise (PN) code.
20. A method as in Claim 1 wherein the cover sequence is a quasi-orthogonal sequence.
21. A method as in Claim 1 wherein the cover sequence is a Walsh code. <Desc/Clms Page number 17> 22. A method as in Claim 1 wherein cover sequence circuit decoding process uses a modulo 2 multiplication to provide the candidate frame.
23. A system for communication in a time division multiplex system wherein access to a shared physical channel is assigned on a demand basis by allocating timeslots to provide multiple connections between transmitters and receivers, each given connection of the multiple connections having a given receiver, comprising : a transmitter, the given receiver having a given connection to the transmitter ; a plurality of time slots operable to carry forward link packet data on a forward link channel, the packet adapted to be subdivided into frames ; an FEC encoder operable to encode the frames with a forward error correction code; a cover sequence encode circuit at the transmitter operable to further encode the frames with a cover sequence unique to the given connection between the transmitter and the given receiver;STDC0616 a combiner, for combining cover sequence encoded frames from the transmitter and at least one other transmitters; a cover sequence decode circuit at the given receiver operable to decode a transmitted frame by combining a received signal with a cover sequence unique to the given receiver of the given connection to provide a candidate frame; and an FEC decoder at the given receiver operable to decode the FEC code using a forward error correction decoding process; the cover sequence encoding operable to be decoded only by the cover sequence unique to the given receiver corresponding to the given connection.
24. A system as in Claim 23 wherein the receiver is further operable to, if the forward error correction decoding process indicates a correctly received candidate frame, forward the candidate frame to a packet assembler in a higher level communication layer. <Desc/Clms Page number 18> 25. A system as in Claim 23 wherein the receiver is further operable to, upon detecting a correctly received candidate frame, pass a positive indication of having correctly received a candidate frame to a higher level communication layer.
26. A system as in Claim 25 wherein the positive indication to the higher communication layer is given in the frame itself.
27. A system as in Claim 23 wherein the receiver is further operable to, upon detecting an incorrectly received candidate frame, then not pass a positive indication of having correctly received a candidate frame to a higher level communication layer.
28. A system as in claim 24 wherein the packet assembler is further operable to, upon detecting a frame error, pass an indication to a still higher communication layer.
29. A system as in claim 28 wherein the frame error is a missing frame.
30. A system as in claim 28 wherein the frame error is an extra frame.
31. A system as in claim 28 wherein the frame error is an out of sequence frame.
32. A system as in claim 28 wherein the receiver is further operable to request retransmission of the erroneous frame.
33. A system as in claim 24 wherein the packet assembler is further operable to discard the packet upon a frame error.
34. A system as in Claim 23 wherein the shared physical channel is a wireless channel. <Desc/Clms Page number 19> 35. A system as in Claim 23 wherein a separate shared access channel provides information to the receiver to decode the frame.
36. A system as in Claim 35 wherein the information to decode the frame is a control message directed from the given transmitter to the given receiver.
37. A system as in Claim 35 wherein the information provided to decode the frame is an indication of the cover sequence.
38. A system as in Claim 23 wherein the cover sequence is provided to the given receiver during a system configuration phase.
39. A sytem as in Claim 23 wherein the cover sequence is provided to the given receiver in response to a channel allocation request.
40. A system as in Claim 23 wherein the cover sequence is a long pseudorandom noise (PN) code.
41. A system as in Claim 23 wherein the cover sequence is not a long psuedorandom noise (PN) code.
42. A system as in Claim 23 wherein the cover sequence is a quasi-orthogonal sequence.
43. A system as in Claim 23 wherein the cover sequence is a Walsh code.
44. A system as in Claim 23 wherein cover sequence decode circuit uses a modulo 2 multiplication to provide the candidate frame.