Method and system for block ARQ with reselection of FEC coding and/or modulation
First Claim
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1. A method for retransmitting a block of information which was previously transmitted using a first type of modulation, a first type of coding and a first transmission format comprising the steps of:
- (a) selecting at least a second type of modulation different from said first type of modulation to create a retransmission processing scheme;
(b) processing only said block in accordance with said retransmission processing scheme;
(c) formatting said processed block in a second transmission format different from said first transmission format to generate a formatted block; and
(d) retransmitting said formatted block.
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Abstract
A communication system supports multiple modulation/coding schemes. When connection quality drops below an acceptable threshold, ARQ techniques use an alternative modulation/coding scheme which is more resistant to noise and/or interference. Flexible resegmentation and mapping of information blocks is supported.
311 Citations
29 Claims
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1. A method for retransmitting a block of information which was previously transmitted using a first type of modulation, a first type of coding and a first transmission format comprising the steps of:
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(a) selecting at least a second type of modulation different from said first type of modulation to create a retransmission processing scheme;
(b) processing only said block in accordance with said retransmission processing scheme;
(c) formatting said processed block in a second transmission format different from said first transmission format to generate a formatted block; and
(d) retransmitting said formatted block. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
counting a number of erroneously received blocks; and
comparing said number with a predetermined number of blocks.
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4. The method of claim 1, wherein said step of selecting further comprises the step of:
making said selection based upon an estimate of a block error rate.
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5. The method of claim 1, wherein said step of selecting further comprises the step of:
making said selection based upon an estimate of a carrier-to-interference ratio associated with a link over which said block is retransmitted.
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6. The method of claim 1, wherein said step of selecting further comprises the step of:
making said selection based upon a predefined algorithm known to both a receiver and a transmitter associated with a link over which said block is retransmitted.
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7. The method of claim 1, wherein said step of selecting further comprises the steps of:
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receiving, at a transmitter, a request for at least one of said second modulation or said second coding from a receiver associated with a link over which said block is retransmitted; and
making said selection based on said request.
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8. The method of claim 1, wherein said step of selecting further comprises the steps of:
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determining, at a transmitter associated with a link over which said block is retransmitted, which of said at least one of said second modulation or said second coding are to be selected; and
informing a receiver associated with said link of said retransmission processing scheme.
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9. The method of claim 1, wherein said step of selecting further comprises the step of:
selecting said second type of modulation.
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10. The method of claim 9, wherein said first type of modulation is a high level modulation and said second type of modulation is a low level modulation.
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11. The method of claim 9, wherein said second type of modulation uses a subset of signal points associated with said first type of modulation.
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12. The method of claim 1, further comprising the step of:
selecting a second type of coding different from said first type of coding to create the retransmission processing scheme.
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13. A method of claim 12, wherein said step of selecting further comprises the step of:
selecting said second type of coding.
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14. The method of claim 13, wherein said first type of coding has a first umber of code bits per data bit and said second type of coding has a second number of code bits per data bit, said second number being greater than said first number.
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15. The method of claim 1, wherein said first and second transmission formats both include transmission bursts into which said block of data is mapped.
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16. The method of claim 1, wherein said block is interleaved over a first number of bursts in said first transmission format and a second number of bursts in said second transmission format, said first and second numbers being different.
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17. The method of claim 1, wherein said step of formatting further comprises the step of:
altering mapping between said block and physical layer units from said first transmission format to said second transmission format.
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18. The method of claim 1, wherein said step of formatting further comprises the step of:
dividing said block into at least two blocks.
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19. A method for retransmitting a block of information which was previously transmitted using a first type of modulation and a first type of coding comprising the steps of:
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dividing said block into at least two blocks;
selecting a retransmission processing scheme comprising a second type of coding and a second type of modulation;
encoding said at least two blocks using said second type of coding;
mapping said at least two blocks into a transmission format;
modulating said mapped blocks using said second type of modulation to generate a modulated signal; and
retransmitting said modulated signal. - View Dependent Claims (20, 21, 22, 23, 24, 25)
interleaving said at least two blocks over eight TDMA bursts.
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24. The method of claim 19, wherein said second type of modulation uses a subset of the amplitude coefficients of said first type of modulation.
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25. The method of claim 19, wherein said step of mapping said at least two blocks into a transmission format further comprises the step of:
adapting said at least two blocks for CDMA transmission.
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26. A transceiving unit comprising:
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means for receiving a negative acknowledgement signal indicating that a block was erroneously received;
means for selectively switching from a first modulation/FEC coding scheme to a second modulation/FEC coding scheme different than said first modulation/FEC coding scheme for processing said block in response to said acknowledgement signal; and
means for retransmitting said block after processing using said second modulation/FEC coding scheme, but continuing to transmit other blocks using said first modulation/FEC coding scheme. - View Dependent Claims (27, 28)
means for counting a number of said negative acknowledgement signals; and
means for switching from said first modulation/FEC coding scheme to said second modulation/FEC coding scheme when said counted number exceeds a predetermined threshold.
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28. The transceiving unit of claim 26, wherein said means for selectively switching further comprises:
means for selecting said second modulation/FEC coding scheme from a lurality of modulation/FEC coding schemes based upon a predetermined system characteristic.
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29. A transceiving unit comprising:
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means for receiving a negative acknowledgment signal indicating that a block was erroneously received;
means for selectively dividing said block into at least two blocks in response to said negative acknowledgment signal; and
means for retransmitting said at least two blocks, wherein said block was originally transmitted using a first modulation/FEC coding scheme and only said at least two blocks are retransmitted using a second modulation/FEC coding scheme different from said first modulation/FEC coding scheme.
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Specification