Receiver, transmitter, communication network, data signal and method improving a retransmission process in a communication network
Data to be transmitted over a channel from a transmitter to a receiver is encoded to obtain a codeword. The codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing the code. The codeword is transmitted over the channel such that certain variable nodes are transmitted prior to other variable nodes. The certain variable nodes are associated with a subset of the check nodes of the bipartite graph and define a subcodeword known at the receiver. At the receiver, a decodability of the transmitted codeword is estimated using the subcodeword prior to receiving all variable nodes of the codeword.
1. A receiver for receiving data in a communication network, comprising
a receive unit configured to receive data over a channel from a transmitter, wherein the data is parity-check enclosed to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing code, wherein the codeword is received over the channel such that certain variable nodes of the plurality of variable nodes, which are associated with a subset of the check nodes of the bipartite graph, are received prior to remaining variable nodes of the plurality of variable nodes, and wherein the certain variable nodes define a subcodeword known by the receiver; and
a decoder configured to estimate a decodability of the transmitted codeword using the subcodeword prior to receiving all variable nodes of the codeword,
wherein responsive to an estimation indicating that the codeword cannot be decoded, the receiver is configured to request from the transmitter a retransmission of the data and/or additional redundancy, and
wherein responsive to an estimation indicating that the codeword can be decoded, the receiver is to signal the transmitter to not retransmit the data and/or stop transmitting additional redundancy.
2. The receiver of claim 1 , wherein the receiver is configured to determine a level of confidence of the estimation result, and to determine, based on the level of confidence, the additional redundancy to request from the transmitter.
3. The receiver of claim 1 , wherein the additional redundancy comprises chase combining, or incremental redundancy, or additional redundancy comprising new data acquired through coupling.
4. The receiver of claim 1 , wherein the receiver is configured to estimate the decodability of the codeword using information associated with all of the plurality of check nodes of the bipartite graph defining the subcodeword.
5. The receiver of claim 1 ,
wherein the receiver is configured to initially estimate the decodability of the codeword using information associated with a first number of the plurality of check nodes of the bipartite graph defining the subcodeword, and
wherein, responsive to an estimation indicating that the codeword cannot be decoded, the receiver is configured to estimate the decodability of the codeword using information associated with a second number of the plurality of check nodes of the bipartite graph defining the subcodeword, the second number being higher than the first number.
6. The receiver of claim 5 , wherein, responsive to an estimation indicating that the codeword cannot be decoded, the receiver is configured to repeat estimating the decodability of the codeword using an increasing number of the plurality of check nodes of the bipartite graph defining the subcodeword.
7. The receiver of claim 6 , wherein the receiver is configured to repeat estimating the decodability of the codeword until a predefined number of the plurality of check nodes of the bipartite graph defining the subcodeword has been used, and/or until a time is reached to signal the transmitter that additional redundancy is needed or not such that at the beginning of the next transmission interval the additional redundancy or, in case there is a new codeword for the receiver, the new codeword is received.
8. The receiver of claim 1 , comprising a Maximum-Likelihood decoder or belief-propagation based decoder to estimate the codeword.
9. A transmitter for transmitting data in a communication network, comprising:
an encoder configured to parity-check encode data to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing code; and
a transmit unit configured to transmit the codeword over a channel to a receiver such that certain variable nodes of the plurality of variable nodes, which are associated with a subset of the check nodes of the bipartite graph, are transmitted prior to remaining variable nodes of the plurality of variable nodes,
wherein the certain variable nodes define a subcodeword known at the receiver and used by the receiver to estimate a decodability of the transmitted codeword prior to receiving all variable nodes of the codeword, and
wherein the transmit unit, responsive to a signal from the receiver, is configured to perform a retransmission of the data and/or transmit additional redundancy, or to not perform a retransmission of the data and/or to stop transmitting additional redundancy.
10. The transmitter of claim 9 , wherein the signal from the receiver indicates the additional redundancy.
11. The transmitter of claim 9 , wherein the additional redundancy comprises chase combining, or incremental redundancy, additional redundancy comprising new data acquired through coupling.
12. A communication network for transmitting data, comprising:
a receiver, comprising
a receive unit configured to receive data over a channel from a transmitter, wherein the data is parity-check encoded to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing code, wherein the codeword is received over the channel such that certain variable nodes of the plurality of variable nodes, which are associated with a subset of the check nodes of the bipartite graph, are received prior to remaining variable nodes of the plurality of variable nodes, and wherein the certain variable nodes define a subcodeword known by the receiver; and
a decoder configured to estimate a decodability of the transmitted codeword using the subcodeword prior to receiving all variable nodes of the codeword,
wherein, responsive to an estimation indicating that the codeword cannot be decoded, the receiver is configured to request from the transmitter a retransmission of the data and/or additional redundancy, and
wherein, responsive to an estimation indicating that the codeword can be decoded, the receiver is configured to signal the transmitter to not retransmit the data and/or to stop transmitting additional redundancy, and
a transmitter of claim 9 .
13. The communication network of claim 12 , wherein the communication network comprises a wired communication network, a wireless communication network, a cellular network, a wireless local area network or a wireless sensor system.
14. The communication network of claim 12 , wherein the receiver is a mobile terminal, an IoT device or a base station of a wireless communication network, and wherein the transmitter is a mobile terminal, an IoT device or a base station of the wireless communication network.
15. The communication network of claim 14 , using an IFFT (Inverse Fast Fourier Transform) based signal, wherein the IFFT based signal comprises OFDM with CP, DFT-s-OFDM with CP, IFFT-based waveforms without CP, f-OFDM, FBMC, GFDM or UFMC.
16. A method for operating a receiver of a communication network, the method comprising
receiving data over a channel from a transmitter, wherein the data is parity-check encoded to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing code, wherein the codeword is received over the channel such that certain variable nodes of the plurality of variable nodes, which are associated with a subset of the check nodes of the bipartite graph, are received prior to remaining variable nodes of the plurality of variable nodes, and wherein the certain variable nodes define a subcodeword known by the receiver; and
estimating a decodability of the transmitted codeword using the subcodeword prior to receiving all variable nodes of the codeword,
responsive to an estimation indicating that the codeword cannot be decoded, requesting from the transmitter a retransmission of the data and/or additional redundancy; and
responsive to an estimation indicating that the codeword can be decoded, signaling the transmitter to not retransmit the data and/or to stop transmitting additional redundancy.
17. A method for operating a transmitter of a communication network, the method comprising:
parity-check encoding data to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing t-code;
transmitting the codeword over a channel to a receiver such that certain variable nodes of the plurality of variable nodes, which are associated with a subset of the check nodes of the bipartite graph, are transmitted prior to remaining variable nodes of the plurality of variable nodes, wherein the certain variable nodes define a subcodeword known at the receiver and used by the receiver to estimate a decodability of the transmitted codeword prior to receiving all variable nodes of the codeword; and
responsive to a signal from the receiver, retransmitting the data and/or transmitting additional redundancy, or not retransmitting the data and/or stopping transmitting additional redundancy.
18. A method for operating a communication network, the method comprising:
encoding data to be transmitted over a channel from a transmitter to a receiver, wherein the data is parity-check encoded to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing code;
transmitting the codeword over the channel such that certain variable nodes of the plurality of variable nodes are transmitted prior to remaining variable nodes of plurality of variable nodes, wherein the certain variable nodes are associated with a subset of the check nodes of the bipartite graph and define a subcodeword known at the receiver;
estimating, at the receiver, a decodability of the transmitted codeword using the subcodeword prior to receiving all variable nodes of the codeword,
responsive to an estimation indicating that the codeword cannot be decoded, requesting from the transmitter a retransmission of the data and/or additional redundancy; and
responsive to an estimation indicating that the codeword can be decoded, signaling the transmitter to not a retransmit the data and/or to stop transmitting additional redundancy.
19. The method of claim 18 , comprising determining a level of confidence of the estimation result, and determining, based on the level of confidence, the additional redundancy to request from the transmitter.
20. The method of claim 18 , wherein the additional redundancy comprises chase combining, or incremental redundancy, or additional redundancy comprising new data acquired through coupling.
21. The method of claim 18 , wherein estimating the decodability comprises estimating the decodability of the codeword using information associated with all of the plurality of check nodes of the bipartite graph defining the subcodeword.
22. The method of claim 18 , wherein estimating the decodability comprises:
initially estimating the decodability of the codeword using information associated with a first number of the plurality of check nodes of the bipartite graph defining the subcodeword, and
responsive to an estimation indicating that the codeword cannot be decoded, estimating the decodability of the codeword using information associated with a second number of the plurality of check nodes of the bipartite graph defining the subcodeword, the second number being higher than the first number.
23. The method of claim 22 , comprising, responsive to an estimation indicating that the codeword cannot be decoded, repeating estimating the decodability of the codeword using an increasing number of the plurality of check nodes of the bipartite graph defining the subcodeword.
24. The method of claim 23 , wherein estimating the decodability of the codeword is repeated until a predefined number of the plurality of check nodes of the bipartite graph defining the subcodeword has been used, and/or until a time is reached to signal the transmitter that additional redundancy is needed or not such that at the beginning of the next transmission interval the additional redundancy or, in case there is a new codeword to be transmitted at the receiver, the new codeword is received.
25. The method of claim 22 , wherein the information associated with some or all of the plurality of check nodes of the bipartite graph defining the subcodeword is transmitted in a fixed or in an arbitrary order.
26. The method of claim 22 , comprising employing a Maximum-Likelihood decoder or a belief-propagation based decoder to estimate the codeword.
27. The method of claim 18 , wherein the code is a low-density parity-check (LDPC) code.
28. The method of claim 18 , wherein the certain variable nodes associated with a subset of the check nodes of the bipartite graph code, which define the subcodeword, are freely selectable from all of the variable nodes or are predefined variable nodes of all of the variable nodes.
29. A non-transitory digital storage medium having a computer program stored thereon to perform a method for operating a receiver of a communication network, the method comprising:
receiving data over a channel from a transmitter, wherein the data is parity-check encoded to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing the code, wherein the codeword is received over the channel such that certain variable nodes of the plurality of variable nodes, which are associated with a subset of the check nodes of the bipartite graph, are received prior to remaining variable nodes of the plurality of variable nodes, and wherein the certain variable nodes define a subcodeword known by the receiver;
estimating a decodability of the transmitted codeword using the subcodeword prior to receiving all variable nodes of the codeword;
responsive to an estimation indicating that the codeword cannot be decoded, requesting from the transmitter a retransmission of the data and/or additional redundancy; and
responsive to an estimation indicating that the codeword can be decoded, signaling the transmitter to not retransmit the data and/or to stop transmitting additional redundancy,
when said computer program is run by a computer.
30. A non-transitory digital storage medium having a computer program stored thereon to perform a method for operating a tranSmitter of a communication network, the method comprising:
parity-check encoding data to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing code;
transmitting the codeword over a channel to a receiver such that certain variable nodes of the plurality of variable nodes, which are associated with a subset of the check nodes of the bipartite graph, are transmitted prior to remaining variable nodes of the plurality of variable nodes, wherein the certain variable nodes define a subcodeword known at the receiver and used by the receiver to estimate a decodability of the transmitted codeword prior to receiving all variable nodes of the codeword; and
responsive to a signal from the receiver, retransmitting the data and/or transmitting additional redundancy, or not retransmitting the data and/or stopping transmitting additional redundancy,
when said computer program is run by a computer.
31. A non-transitory digital storage medium having a computer program stored thereon to perform a method for operating a communication network, the method comprising:
encoding data to be transmitted over a channel from a transmitter to a receiver, wherein the data is parity-check encoded to acquire a codeword, wherein the codeword is defined by a plurality of variable nodes associated with a plurality of the check nodes of a bipartite graph representing code;
transmitting the codeword over the channel such that certain variable nodes of the plurality of variable nodes are transmitted prior to remaining variable nodes of the plurality of variable nodes, wherein the certain variable nodes are associated with a subset of the check nodes of the bipartite graph and define a subcodeword known at the receiver;
estimating, at the receiver, a decodability of the transmitted codeword using the subcodeword prior to receiving all variable nodes of the codeword;
responsive to an estimation indicating that the codeword cannot be decoded, requesting from the transmitter a retransmission of the data and/or additional redundancy; and
responsive to an estimation indicating that the codeword can be decoded, signaling the transmitter to not retransmit the data and/or stop transmitting additional redundancy,
when said computer program is run by a computer.