EP0797327A2
Expired / Lapsed
EP
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Adaptive hybrid-ARQ coding schemes for slow fading channels in mobile radio systems
Assignee: Nokia of America Corp
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Filing: 1997-03-12
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Granted: —
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Expires: 2017-03-12
Abstract
Abstract In a method and apparatus for performing adaptive hybrid automatic repeat request (ARQ) coding the coding is modified based on the acknowledgements returned by the receiver. In accordance with one illustrative embodiment of the present invention, the state of the channel is implicitly determined by the transmitter based upon the frequency of acknowledgments (ACKs and NACKs) arriving from the receiver. For example, since a NACK implies a weak received signal strength, the code rate of the FEC is advantageously reduced in response to such an acknowledgement. On the other hand, the code rate of the FEC is advantageously increased in response to an ACK. In accordance with another illustrative embodiment of the present invention, the acknowledgement returned by the receiver is modified to convey the number of errors in the corresponding received data packet. In particular, a Reed-Solomon (RS) outer code is employed in the FEC to enable the receiver to determine the number of errors in the received data packet. If the acknowledgement indicates a large number of errors at the receiver, the code rate of the FEC is advantageously reduced in response thereto.
Inventors
- 👤 Zulfiquar Sayeed
- 👤 Vijitha Weerackody
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 13:59
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/004; H04L1/0056; H04L1/0064; H04L1/0065; H04L1/0001; H04L1/0009; H04L1/0033; H04L1/0034; H04L1/0067; H04L1/0068; H04L1/12; H04L1/16; H04L1/1607; H04L1/1671; H04L1/18; H04L1/1812; H04L1/1819
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
116 words
A method of transmitting a signal to a receiver across a wireless communications channel, the method comprising the steps of: encoding a first portion of the signal with a first code to generate a first encoded signal portion; transmitting the first encoded signal portion across the channel to the receiver; receiving acknowledgement data from the receiver, said acknowledgement data comprising information representative of whether the transmitted signal portion was received by the receiver without error; determining a second code based on the received acknowledgement data; encoding a second portion of the signal with the second code to generate a second encoded signal portion; and transmitting the second encoded signal portion across the channel to the receiver.
Claim 2
Dependent Claim
20 words
The method of claim 1 wherein at least one of the first and second codes comprises a full convolutional code.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein at least one of the first and second codes comprises a punctured convolutional code.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein at least one of the first and second codes comprises an error correcting code.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein at least one of the first and second codes comprises a cyclic-redundancy-check code.
Claim 6
Dependent Claim
29 words
The method of claim 5 wherein the cyclic-redundancy-check code comprised in the at least one of the first and second codes is the only error detecting code comprised therein.
Claim 7
Dependent Claim
28 words
The method of claim 1 wherein at least one of the first and second codes comprises a combination of a full convolutional code and an error correcting code.
Claim 8
Dependent Claim
28 words
The method of claim 1 wherein at least one of the first and second codes comprises a combination of a punctured convolutional code and an error correcting code.
Claim 9
Dependent Claim
18 words
The method of claim 4, 7 or 8 wherein the error correcting code comprises a Reed Solomon code.
Claim 10
Dependent Claim
59 words
The method of claim 1 wherein the acknowledgement data received from the receiver further comprises information representative of a number of errors detected by the receiver when the transmitted signal portion was not received by the receiver without error, and wherein the step of determining the second code is based on said number of errors detected by the receiver.
Claim 11
Independent Claim
149 words
An apparatus for transmitting a signal to a remote receiver across a wireless communications channel, the apparatus comprising: a first encoder adapted to encode a first portion of the signal with a first code to generate a first encoded signal portion; a first transmitter adapted to transmit the first encoded signal portion across the channel to the remote receiver; an acknowledgement receiver adapted to receive acknowledgement data from the remote receiver, said acknowledgement data comprising information representative of whether the signal portion transmitted by the first transmitter was received by the remote receiver without error; means for determining a second code based on the received acknowledgement data; a second encoder adapted to encode a second portion of the signal with the second code to generate a second encoded signal portion; and a second transmitter adapted to transmit the second encoded signal portion across the channel to the remote receiver.
Claim 12
Dependent Claim
20 words
The apparatus of claim 11 wherein at least one of the first and second codes comprises a full convolutional code.
Claim 13
Dependent Claim
20 words
The apparatus of claim 11 wherein at least one of the first and second codes comprises a punctured convolutional code.
Claim 14
Dependent Claim
20 words
The apparatus of claim 11 wherein at least one of the first and second codes comprises an error correcting code.
Claim 15
Dependent Claim
19 words
The apparatus of claim 11 wherein at least one of the first and second codes comprises a cyclic-redundancy-check code.
Claim 16
Dependent Claim
29 words
The apparatus of claim 15 wherein the cyclic-redundancy-check code comprised in the at least one of the first and second codes is the only error detecting code comprised therein.
Claim 17
Dependent Claim
28 words
The apparatus of claim 11 wherein at least one of the first and second codes comprises a combination of a full convolutional code and an error correcting code.
Claim 18
Dependent Claim
28 words
The apparatus of claim 11 wherein at least one of the first and second codes comprises a combination of a punctured convolutional code and an error correcting code.
Claim 19
Dependent Claim
18 words
The apparatus of claim 14, 17, or 18 wherein the error correcting code comprises a Reed Solomon code.
Claim 20
Dependent Claim
63 words
The apparatus of claim 11 wherein the acknowledgement data received from the remote receiver further comprises information representative of a number of errors detected by the remote receiver when the transmitted signal portion was not received by the remote receiver without error, and wherein the means for determining the second code is based on said number of errors detected by the remote receiver.
References Cited (Backward Citations)
No citation records indexed.
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