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Haiquan Wang - One of the best experts on this subject based on the ideXlab platform.
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Recursive Space–Time Trellis Codes Using Differential Encoding
IEEE Transactions on Information Theory, 2009Co-Authors: Shengli Fu, Haiquan WangAbstract:Differential space-time modulation (DSTM) has been recently proposed by Hughes, and Hochwald and Sweldens when the channel information is not known at the receiver, where the demodulation is in fact the same as the coherent demodulation of space-time block coding by replacing the channel matrix with the previously received signal matrix. On the other hand, the DSTM also needs a recursive memory of a matrix block at the encoder and therefore provides a trellis structure when the channel information is known at the receiver, which is the interest of this paper. This recursive structure of the DSTM has been adopted lately by Schlegel and Grant in joint with a conventional binary code and joint iterative decoding/demodulation with a superior performance. The number of states of the trellis from the recursive structure depends on both the memory size, which is fixed in this case, and the unitary space-time code (USTC). When a USTC for the DSTM forms a group, the number of states is the same as the size of the USTC, otherwise the number of the states is the size of the semi-group generated by the USTC from all the multiplications of the matrices in the USTC. It is well known in the conventional convolutional coding (CC) or the trellis coded modulation (TCM), the free (Hamming or Euclidean) distance (or the performance) increases when the number of states increases by adding more memory with a properly designed CC or TCM. In this paper, we systematically study and design the USTC/DSTM for the recursive space-time trellis modulation and show that the diversity product increases when the number of states increases, which is not because of the memory size but because of the different USTC designs that generate different sizes of semi-groups. We propose a new USTC design criterion to ensure that the trellis structure improves the diversity product over the USTC as a block code. Based on the new criterion, we propose a new class of USTC design for an arbitrary number of transmit antennas that has an analytical diversity product formula for two transmit antennas. We then follow Schlegel and Grant's approach for joint Encoding and iterative decoding of a binary coded DSTM (turbo space-time coding) and numerically show that our new USTC designs for the recursive space-time trellis modulation outperforms the group USTC used by Schlegel and Grant.
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New Recursive Space-Time Trellis Codes From General Differential Encoding
2006 IEEE Information Theory Workshop - ITW '06 Chengdu, 2006Co-Authors: Shengli Fu, Haiquan WangAbstract:In this paper, a recursive space-time trellis coding (RSTTC) from general Differential Encoding is proposed for multiple antenna systems, where general Differential Encoding is implemented separately from the space-time matrix modulation. The general Differential Encoding is achieved by introducing a new multiplication on a set of symbols (called trellis codewords) such that the corresponding RSTTC has its minimum error event length 3 or above and in the meantime it has the minimum number of states. The space-time matrix modulation is the mapping of the Differentially encoded symbols to a set of space-time matrices (called modulation codewords). Due to the separation of Differential Encoding and space-time matrix modulation, more freedom on the design of modulation codewords (or a space-time code) exists, which may result in a larger diversity product (or determinant distance or product distance or coding advantage) than that the existing combined Differential Encoding and space-time matrix modulation can achieve in the concatenation with an outer binary channel encoder proposed by Schlegel and Grant. A new design of modulation codewords is then proposed for the RSTTC with larger diversity products than the existing schemes. Simulation results are finally presented to show that our new design significantly outperforms the existing schemes
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Recursive space-time trellis codes using Differential Encoding
GLOBECOM '05. IEEE Global Telecommunications Conference 2005., 2005Co-Authors: Shengli Fu, Haiquan WangAbstract:Differential space-time modulation (DSTM) has been recently proposed by Hughes, and Hochwald and Sweldens when the channel information is not known at the receiver. On the other hand, the DSTM also needs a recursive memory of a matrix block at the encoder and therefore provides a trellis structure when the channel information is known at the receiver, which is the interest of this paper. This recursive structure of the DSTM has been adopted lately by Schlegel and Grant as an inner trellis code concatenated with an outer binary code to achieve turbo gain. The number of states of the trellis from the recursive structure depends on both the memory size, which is fixed in this case, and the unitary space-time code (USTC). In this paper, we propose a new USTC design criterion to ensure that the trellis structure improves the diversity product over the USTC as a block code. Based on the new criterion, we propose a new class of USTC design for an arbitrary number of transmit antennas that has an analytical diversity product formula for two transmit antennas. We then follow Schlegel and Grant's approach for joint Encoding and iterative decoding of a binary coded DSTM (turbo space-time coding) and numerically show that our new USTC designs for the recursive space-time trellis modulation outperforms the group USTC used by Schlegel and Grant.
Shengli Fu - One of the best experts on this subject based on the ideXlab platform.
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Recursive Space–Time Trellis Codes Using Differential Encoding
IEEE Transactions on Information Theory, 2009Co-Authors: Shengli Fu, Haiquan WangAbstract:Differential space-time modulation (DSTM) has been recently proposed by Hughes, and Hochwald and Sweldens when the channel information is not known at the receiver, where the demodulation is in fact the same as the coherent demodulation of space-time block coding by replacing the channel matrix with the previously received signal matrix. On the other hand, the DSTM also needs a recursive memory of a matrix block at the encoder and therefore provides a trellis structure when the channel information is known at the receiver, which is the interest of this paper. This recursive structure of the DSTM has been adopted lately by Schlegel and Grant in joint with a conventional binary code and joint iterative decoding/demodulation with a superior performance. The number of states of the trellis from the recursive structure depends on both the memory size, which is fixed in this case, and the unitary space-time code (USTC). When a USTC for the DSTM forms a group, the number of states is the same as the size of the USTC, otherwise the number of the states is the size of the semi-group generated by the USTC from all the multiplications of the matrices in the USTC. It is well known in the conventional convolutional coding (CC) or the trellis coded modulation (TCM), the free (Hamming or Euclidean) distance (or the performance) increases when the number of states increases by adding more memory with a properly designed CC or TCM. In this paper, we systematically study and design the USTC/DSTM for the recursive space-time trellis modulation and show that the diversity product increases when the number of states increases, which is not because of the memory size but because of the different USTC designs that generate different sizes of semi-groups. We propose a new USTC design criterion to ensure that the trellis structure improves the diversity product over the USTC as a block code. Based on the new criterion, we propose a new class of USTC design for an arbitrary number of transmit antennas that has an analytical diversity product formula for two transmit antennas. We then follow Schlegel and Grant's approach for joint Encoding and iterative decoding of a binary coded DSTM (turbo space-time coding) and numerically show that our new USTC designs for the recursive space-time trellis modulation outperforms the group USTC used by Schlegel and Grant.
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LDGM coded space-time trellis codes from Differential Encoding
IEEE Communications Letters, 2007Co-Authors: Shengli Fu, Javier Garcia-friasAbstract:In this letter, we investigate the concatenation of a low density generator matrix (LDGM) outer code and a recursive space time trellis (RSTTC) inner code based on Differential Encoding. We provide guidelines for the design of the LDGM outer code and observe that previous schemes based on parity check outer codes are particular cases of the proposed framework
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New Recursive Space-Time Trellis Codes From General Differential Encoding
2006 IEEE Information Theory Workshop - ITW '06 Chengdu, 2006Co-Authors: Shengli Fu, Haiquan WangAbstract:In this paper, a recursive space-time trellis coding (RSTTC) from general Differential Encoding is proposed for multiple antenna systems, where general Differential Encoding is implemented separately from the space-time matrix modulation. The general Differential Encoding is achieved by introducing a new multiplication on a set of symbols (called trellis codewords) such that the corresponding RSTTC has its minimum error event length 3 or above and in the meantime it has the minimum number of states. The space-time matrix modulation is the mapping of the Differentially encoded symbols to a set of space-time matrices (called modulation codewords). Due to the separation of Differential Encoding and space-time matrix modulation, more freedom on the design of modulation codewords (or a space-time code) exists, which may result in a larger diversity product (or determinant distance or product distance or coding advantage) than that the existing combined Differential Encoding and space-time matrix modulation can achieve in the concatenation with an outer binary channel encoder proposed by Schlegel and Grant. A new design of modulation codewords is then proposed for the RSTTC with larger diversity products than the existing schemes. Simulation results are finally presented to show that our new design significantly outperforms the existing schemes
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Recursive space-time trellis codes using Differential Encoding
GLOBECOM '05. IEEE Global Telecommunications Conference 2005., 2005Co-Authors: Shengli Fu, Haiquan WangAbstract:Differential space-time modulation (DSTM) has been recently proposed by Hughes, and Hochwald and Sweldens when the channel information is not known at the receiver. On the other hand, the DSTM also needs a recursive memory of a matrix block at the encoder and therefore provides a trellis structure when the channel information is known at the receiver, which is the interest of this paper. This recursive structure of the DSTM has been adopted lately by Schlegel and Grant as an inner trellis code concatenated with an outer binary code to achieve turbo gain. The number of states of the trellis from the recursive structure depends on both the memory size, which is fixed in this case, and the unitary space-time code (USTC). In this paper, we propose a new USTC design criterion to ensure that the trellis structure improves the diversity product over the USTC as a block code. Based on the new criterion, we propose a new class of USTC design for an arbitrary number of transmit antennas that has an analytical diversity product formula for two transmit antennas. We then follow Schlegel and Grant's approach for joint Encoding and iterative decoding of a binary coded DSTM (turbo space-time coding) and numerically show that our new USTC designs for the recursive space-time trellis modulation outperforms the group USTC used by Schlegel and Grant.
Parimal Parag - One of the best experts on this subject based on the ideXlab platform.
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Fixed Length Differential Encoding for Real-Time Status Updates
IEEE Transactions on Communications, 2019Co-Authors: Sanidhay Bhambay, Sudheer Poojary, Parimal ParagAbstract:We consider the status updates of a physical process over an unreliable channel. In this setting, one may not be able to reliably transmit the current state at all times. Instead, one is interested in the timeliness of the accurately received information. This is a setting for several cyber-physical system applications that require real-time monitoring and control. In this paper, we study periodic data transmission schemes at a single source which exploit the temporal correlation in the source messages. When the source has no feedback, it can periodically send the actual information, interspersed with Differential messages. On the availability of receiver's feedback at the source, it can decide to send either the Differential or the actual information at each transmission opportunity. For a fixed length coding, we show that the Differential Encoding improves the timeliness performance only if the receiver's feedback is available.
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Differential Encoding for Real-Time Status Updates
2017 IEEE Wireless Communications and Networking Conference (WCNC), 2017Co-Authors: Sanidhay Bhambay, Sudheer Poojary, Parimal ParagAbstract:For many applications in sensor networks and cyber-physical systems, receiving timely information is of utmost importance. In this article, we study data transmission schemes for a single source, sending periodic updates to a receiver through an unreliable channel. We consider two schemes that exploit the temporal correlation in the source messages, to send Differential information to the receiver. Taking advantage of the receiver feedback in the first scheme, the source can decide between the Differential and the actual information, to be sent at each transmission opportunity. Contrastingly, in the second scheme without any feedback, the source periodically sends the actual information, interspersed with Differential messages. We observe that the Differential Encoding improves the timeliness performance, only if the receiver feedback is available.
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WCNC - Differential Encoding for Real-Time Status Updates
2017 IEEE Wireless Communications and Networking Conference (WCNC), 2017Co-Authors: Sanidhay Bhambay, Sudheer Poojary, Parimal ParagAbstract:For many applications in sensor networks and cyber-physical systems, receiving timely information is of utmost importance. In this article, we study data transmission schemes for a single source, sending periodic updates to a receiver through an unreliable channel. We consider two schemes that exploit the temporal correlation in the source messages, to send Differential information to the receiver. Taking advantage of the receiver feedback in the first scheme, the source can decide between the Differential and the actual information, to be sent at each transmission opportunity. Contrastingly, in the second scheme without any feedback, the source periodically sends the actual information, interspersed with Differential messages. We observe that the Differential Encoding improves the timeliness performance, only if the receiver feedback is available.
Sanidhay Bhambay - One of the best experts on this subject based on the ideXlab platform.
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Fixed Length Differential Encoding for Real-Time Status Updates
IEEE Transactions on Communications, 2019Co-Authors: Sanidhay Bhambay, Sudheer Poojary, Parimal ParagAbstract:We consider the status updates of a physical process over an unreliable channel. In this setting, one may not be able to reliably transmit the current state at all times. Instead, one is interested in the timeliness of the accurately received information. This is a setting for several cyber-physical system applications that require real-time monitoring and control. In this paper, we study periodic data transmission schemes at a single source which exploit the temporal correlation in the source messages. When the source has no feedback, it can periodically send the actual information, interspersed with Differential messages. On the availability of receiver's feedback at the source, it can decide to send either the Differential or the actual information at each transmission opportunity. For a fixed length coding, we show that the Differential Encoding improves the timeliness performance only if the receiver's feedback is available.
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Differential Encoding for Real-Time Status Updates
2017 IEEE Wireless Communications and Networking Conference (WCNC), 2017Co-Authors: Sanidhay Bhambay, Sudheer Poojary, Parimal ParagAbstract:For many applications in sensor networks and cyber-physical systems, receiving timely information is of utmost importance. In this article, we study data transmission schemes for a single source, sending periodic updates to a receiver through an unreliable channel. We consider two schemes that exploit the temporal correlation in the source messages, to send Differential information to the receiver. Taking advantage of the receiver feedback in the first scheme, the source can decide between the Differential and the actual information, to be sent at each transmission opportunity. Contrastingly, in the second scheme without any feedback, the source periodically sends the actual information, interspersed with Differential messages. We observe that the Differential Encoding improves the timeliness performance, only if the receiver feedback is available.
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WCNC - Differential Encoding for Real-Time Status Updates
2017 IEEE Wireless Communications and Networking Conference (WCNC), 2017Co-Authors: Sanidhay Bhambay, Sudheer Poojary, Parimal ParagAbstract:For many applications in sensor networks and cyber-physical systems, receiving timely information is of utmost importance. In this article, we study data transmission schemes for a single source, sending periodic updates to a receiver through an unreliable channel. We consider two schemes that exploit the temporal correlation in the source messages, to send Differential information to the receiver. Taking advantage of the receiver feedback in the first scheme, the source can decide between the Differential and the actual information, to be sent at each transmission opportunity. Contrastingly, in the second scheme without any feedback, the source periodically sends the actual information, interspersed with Differential messages. We observe that the Differential Encoding improves the timeliness performance, only if the receiver feedback is available.
Bo-shuan Lu - One of the best experts on this subject based on the ideXlab platform.
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correction to tcm with Differential Encoding set partitioning trellis designs and distance analysis
IEEE Transactions on Communications, 2016Co-Authors: James A. Ritcey, Bo-shuan LuAbstract:We present a correction to [1] . In Table III, $d_{free}^{2}$ for new codes with $L=32$ should be 3.561 (instead of 3.667) and 3.233 (instead of 3.385) for TCM-DE and DTCM, respectively. The corresponding paragraph on the same page, “For $L=32$ , the best $d'^{2}_{free}$ is …… in simulations.” should be modified as “For $L=32$ , the best $d'^{2}_{free}$ is $5\Delta _{1}^{2}+2\Delta _{0}^{2}$ (for instance, two paths (0,0,0,0,0,0) and (0,2,0,1,2,2), so the resulting minimum squared distance is $\min [\Delta _{2}^{2},d'^{2}_{free}=3.233]=3.233$ for 8PSK. There are some codes that have the best $d'^{2}_{free}$ and we choose (C0,C2),(C3,C1),(C3,C1),(C2,C0),(C2,C0),(C1,C3) and (C1,C3) for $\sigma ^{(1)},\cdots ,\sigma ^{(7)}$ in simulations.”. In addition, the trellis diagram in Fig. 12(b) should be corrected to Fig. 1 .
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TCM With Differential Encoding: Set Partitioning, Trellis Designs, and Distance Analysis
IEEE Transactions on Communications, 2015Co-Authors: James A. Ritcey, Bo-shuan LuAbstract:Differential Encoding (DE) is a classical technique at the transmitter that allows simple noncoherent detection at the receiver. On the other hand, trellis-coded modulation (TCM) is a bandwidth efficient technique which offers reliable data transmission. In this paper, we aim to find the best concatenation order of TCM and DE for channel phase coherence over N=2 symbols. Besides the well-known TCM followed by DE (called TCM-DE) , we propose a new trellis coding extension of DE which extends our earlier work, called Differential trellis coded modulation (DTCM) . DTCM is TCM with DE defined in states where distinct states may have distinct DE functions. We propose design methods of DE functions for noncoherently non-catastrophic DTCM. For both TCM-DE and DTCM, we propose additive distance measures and set partitioning. Based on the proposed set partitioning, trellis codes are designed or searched for both TCM-DE and DTCM. Both minimum distances and simulation results show that TCM-DE outperforms DTCM and the obtained new codes are better than the original codes.