A design of super-orthogonal space-time trellis codes （SOSTTCs） based on the trace criterion （TC） is proposed for improving the design of SOSTTCs. The shortcomings of the rank and determinant criteria based design...A design of super-orthogonal space-time trellis codes （SOSTTCs） based on the trace criterion （TC） is proposed for improving the design of SOSTTCs. The shortcomings of the rank and determinant criteria based design and the advantages of the TC-based design are analyzed. The optimization principle of four factors is presented, which includes the space-time block coding （STBC） scheme, set partitioning, trellis structure, and the assignment of signal subsets and STBC schemes in the trellis. According to this principle, systematical and handcrafted design steps are given in detail. By constellation expansion, the code performance can be further improved. The code design results are given, and the new codes outperform others in the simulation.展开更多
Space time coding can provide high data rate and performance gain for wireless communication system. Performance comparison of space time trellis codes and space time transmit diversity is carried out under the sam...Space time coding can provide high data rate and performance gain for wireless communication system. Performance comparison of space time trellis codes and space time transmit diversity is carried out under the same bandwidth efficiency in this paper. We also propose some optimum low rate space time trellis codes in quasi static Rayleigh fading chan￣nel. Performance analysis and simulation show that the low rate space time trellis codes outperform space time transmit diversity at the same bandwidth efficiency, and are more suitable for the power limited wireless communication system which has no strict requirement on bandwidth efficiency.展开更多
In this paper, a novel multiple trellis coded orthogonal transmit scheme is proposed to exploit transmit diversity in fading channels. In this scheme, a unique vector from a set of orthogonal vectors is assigned to ea...In this paper, a novel multiple trellis coded orthogonal transmit scheme is proposed to exploit transmit diversity in fading channels. In this scheme, a unique vector from a set of orthogonal vectors is assigned to each transmit antenna. Each of the output symbols from the multiple trellis encoder is multiplied with one of these orthogonal vectors and transmitted from corresponding transmit antennas. By correlating with corresponding orthogonal vectors, the receiver separates symbols transmitted from different transmit antennas. This scheme can be adopted in coherent/differential systems with any number of transmit antennas. It is shown that the proposed scheme encompasses the conventional trellis coded unitary space-time modulation based on the optimal cyclic group codes as a special case. We also propose two better designs over the conventional trellis coded unitary space-time modulation. The first design uses 8 Phase Shift Keying （8-PSK） constellations instead of 16 Phase Shift Keying （16-PSK） constellations in the conventional trellis coded unitary space-time modulation. As a result, the product distance of this new design is much larger than that of the conventional trellis coded unitary space-time modulation. The second design introduces constellations with multiple levels of amplitudes into the design of the multiple trellis coded orthogonal transmit scheme. For both designs, simulations show that multiple trellis coded orthogonal transmit schemes can achieve better performance than the conventional trellis coded unitarv space-time schemes.展开更多
Space-time trellis codes can achieve the best tradeoff among bandwidth efficiency, diversity gain, constellation size and trellis complexity. In this paper, some optimum low rate space-time trellis codes are proposed....Space-time trellis codes can achieve the best tradeoff among bandwidth efficiency, diversity gain, constellation size and trellis complexity. In this paper, some optimum low rate space-time trellis codes are proposed. Performance analysis and simulation show that the low rate space-time trellis codes outperform space-time block codes concatenated with convolutional code at the same bandwidth efficiency, and are more suitable for the power limited wireless communication system.展开更多
The known design criterions of Space-Time Trellis Codes （STFC） on slow Rayleigh fading channel are rank, determinant and trace criterion. These criterions are not advantageous not onlv in operation but also in perfo...The known design criterions of Space-Time Trellis Codes （STFC） on slow Rayleigh fading channel are rank, determinant and trace criterion. These criterions are not advantageous not onlv in operation but also in performance. With classifying the error events of STTC, a new criterion was presented on slow Rayleigh fading channels. Basod on the criterion, an effective and straighttbrward multi-step method is proposed to ennstruet codes with better performance. This method can reduce the computation of search to small enough. Simulation results show that the codes searched by computer have the same or even better performance than the repored codes.展开更多
Space time trellis coding （STTC） techniques have been proposed to achieve both diversity and coding gains in multiple input multiple output （MIMO） fading channels. But with more transmit antennas STTCs suffer from...Space time trellis coding （STTC） techniques have been proposed to achieve both diversity and coding gains in multiple input multiple output （MIMO） fading channels. But with more transmit antennas STTCs suffer from the design dificulty and complexity increasing. This paper proposes a scheme, named parallel concatenated space time trellis codes （PC-STTC）, to achieve the tradeoff between the performances and complexity of STTCs for a large number of transmit antennas. Simulation results and complexity comparison are provided to demonstrate the performance and superiority of the proposed scheme over conventional schemes in fast fading channels in low signal-to-noise ratio （SNR） regions. And an EXIT （extrinsic information transform） chart is given to analyze the iterative convergence of the proposed scheme. It shows that PC-STTC has better iterative convergence in low SNR regions.展开更多
In this paper, STC with water-filling transmit power distribution in MISO system is proposed when the partial channel information feedback is possible, for example, at slow fading scenario. The performances of the wat...In this paper, STC with water-filling transmit power distribution in MISO system is proposed when the partial channel information feedback is possible, for example, at slow fading scenario. The performances of the water-filling STC including water-filling STTC and water-filling STBC are analyzed. Performance comparison of the Ungerboeck's 2/3 trellis coded 8PSK modulated 2-STBC and 2-STTCs with QPSK is given out in different channel correlation.展开更多
Wireless sensor network （WSN） requires robust and efficient communication protocols to minimise delay and save energy. The lifetime of WSN can be maximised by selecting proper medium access control （MAC） scheme de...Wireless sensor network （WSN） requires robust and efficient communication protocols to minimise delay and save energy. The lifetime of WSN can be maximised by selecting proper medium access control （MAC） scheme depending on the contention level of the network. The throughput of WSN however reduces due to channel fading effects even with the proper design of MAC protocol. Hence this paper proposes a new MAC scheme for enabling packet transmission using cooperative multi-input multi-output （MIMO） utilising space time codes（STC） such as space time block code （STBC）, space time trellis code （STTC） to achieve higher energy savings and lower delay by allowing nodes to transmit and receive information jointly. The performance of the proposed MAC protocol is evaluated in terms of transmission error probability, energy consumption and delay. Simulation results show that the proposed cooperative MIMO MAC protocol provides reliable and efficient transmission by leveraging MIMO diversity gains.展开更多
In this paper we use trellis coded amplitude modulation (TC-AM) as models to analyze the receivers with intersymbol interference (ISI) under BPSK and π/4-QPSK modulations.Using the modified generating function and th...In this paper we use trellis coded amplitude modulation (TC-AM) as models to analyze the receivers with intersymbol interference (ISI) under BPSK and π/4-QPSK modulations.Using the modified generating function and the weight profile function of the TC-AM,the bit error probability for both cases is evaluated in the sense of maximum likelihood decoding.The numerical result is given.展开更多
Parallel concatenated spa ce time trellis code modulation, called Turbo STCM, can efficiently increase the coding gains of the space time codes. However, the complexity of the iterat iv e decoding restricts its ap...Parallel concatenated spa ce time trellis code modulation, called Turbo STCM, can efficiently increase the coding gains of the space time codes. However, the complexity of the iterat iv e decoding restricts its application. This paper introduces a lower complex deco ding algorithm based on soft output Viterbi algorithm (SOVA) for Turbo STCM. S imulational results show that the new SOVA algorithm for the Turbo STCM outperf orms the original space time trellis code (STTC) by 4~6 dB. At the same time, compared with the Max Log MAP (maximum a posteriori) algorithm, the new scheme requires a lower complexity and approaches the performance of Turbo STCM decod ing w ith Max Log MAP.展开更多
Two different set partitioning strategies used in Turbo TCM, UP （Ungerboeck Partitioning） and BP （Block Partitioning） are compared over Rayleigh fading channels. The performance of Turbo TCM with the two set parti...Two different set partitioning strategies used in Turbo TCM, UP （Ungerboeck Partitioning） and BP （Block Partitioning） are compared over Rayleigh fading channels. The performance of Turbo TCM with the two set partitioning strategies and different frame length over Rayleigh fading channels is evaluated. The simulation results of 8PSK and 8ASK modulation and some significant conclusions are also given in this paper.展开更多
Coded overlapped code division multiplexing system with Turbo product structure （TPC-OVCDM） is introduced, and trellis coded modulation （TCM） code is employed as error correcting code for uncoded overlapped code d...Coded overlapped code division multiplexing system with Turbo product structure （TPC-OVCDM） is introduced, and trellis coded modulation （TCM） code is employed as error correcting code for uncoded overlapped code division multiplexing （OVCDM） system. In such a scheme, row code and column code are TCM and OVCDM spreading code, respectively. Data bits are only encoded directly by TCM and transformed into a matrix. Each column of this matrix is then permuted by symbol interleaver before being encoded by OVCDM spreading code. During iterative decoding process in the receiver, two constituent decoders use symbol by symbol BCJR algorithm in the log domain. The order of decoding two sub-codes is determined by the encoding order. The proportion of TCM coding and OVCDM coding affects system performance. For fixed coding structure and symbol interleaver, the performance of TPC-OVCDM systems of different proportions of additive white Gaussian noise （AWGN） channel have been simulated. The results show that TPC-OVCDM system of reasonable proportion can achieve significant coding gain, compared with uncoded OVCDM system under the condition of same spectral efficiency at bit error rate （BER） level of 10^-5.展开更多
Let C be a free cyclic code over Zp^a and dim pC = k. In the paper, we prove that if the k characteristic generators of C are p-linearly independent then the corresponding nα- k characteristic generators of C^⊥ are ...Let C be a free cyclic code over Zp^a and dim pC = k. In the paper, we prove that if the k characteristic generators of C are p-linearly independent then the corresponding nα- k characteristic generators of C^⊥ are p-linearly independent. We then show that to any trellis that can be constructed from k p-linearly independent characteristic generators of C, there exists a trellis for C^⊥ with the same state-complexity profile, which generalizes the conjecture of Koetter and Vardy to a free cyclic code over Zpo.展开更多
Propagation properties of polarized anisotropic crystals were investigated four-petal Gaussian beams along the optical axis of uniaxially Based on the paraxially vectorial theory of beam propagation analytic expressio...Propagation properties of polarized anisotropic crystals were investigated four-petal Gaussian beams along the optical axis of uniaxially Based on the paraxially vectorial theory of beam propagation analytic expressions of the diffraction light field larization properties of the diffracted four-petal were obtained. The effects of the anisotropy on the po- Gaussian beams have also been explained by numerical method. The results elucidate that the linear polarization state and the symmetry of the incident beams cannot be kept during propagation in anisotropic crystals.展开更多
We derived the theoretical results of soliton interactions in optical fiber with super-Gaussian sliding-frequency filters. The results demonstrate that the interactions between optical fiber solitons can be effectivel...We derived the theoretical results of soliton interactions in optical fiber with super-Gaussian sliding-frequency filters. The results demonstrate that the interactions between optical fiber solitons can be effectively suppressed by super-Gaussian sliding-frequency filters. And the results also show that the super-Gaussian filter with sliding is more effective in suppressing soliton interactions than that without sliding.展开更多
文摘A design of super-orthogonal space-time trellis codes （SOSTTCs） based on the trace criterion （TC） is proposed for improving the design of SOSTTCs. The shortcomings of the rank and determinant criteria based design and the advantages of the TC-based design are analyzed. The optimization principle of four factors is presented, which includes the space-time block coding （STBC） scheme, set partitioning, trellis structure, and the assignment of signal subsets and STBC schemes in the trellis. According to this principle, systematical and handcrafted design steps are given in detail. By constellation expansion, the code performance can be further improved. The code design results are given, and the new codes outperform others in the simulation.
文摘Space time coding can provide high data rate and performance gain for wireless communication system. Performance comparison of space time trellis codes and space time transmit diversity is carried out under the same bandwidth efficiency in this paper. We also propose some optimum low rate space time trellis codes in quasi static Rayleigh fading chan￣nel. Performance analysis and simulation show that the low rate space time trellis codes outperform space time transmit diversity at the same bandwidth efficiency, and are more suitable for the power limited wireless communication system which has no strict requirement on bandwidth efficiency.
基金Supported by the National Natural Science Foundation of China(No.60390540).
文摘In this paper, a novel multiple trellis coded orthogonal transmit scheme is proposed to exploit transmit diversity in fading channels. In this scheme, a unique vector from a set of orthogonal vectors is assigned to each transmit antenna. Each of the output symbols from the multiple trellis encoder is multiplied with one of these orthogonal vectors and transmitted from corresponding transmit antennas. By correlating with corresponding orthogonal vectors, the receiver separates symbols transmitted from different transmit antennas. This scheme can be adopted in coherent/differential systems with any number of transmit antennas. It is shown that the proposed scheme encompasses the conventional trellis coded unitary space-time modulation based on the optimal cyclic group codes as a special case. We also propose two better designs over the conventional trellis coded unitary space-time modulation. The first design uses 8 Phase Shift Keying （8-PSK） constellations instead of 16 Phase Shift Keying （16-PSK） constellations in the conventional trellis coded unitary space-time modulation. As a result, the product distance of this new design is much larger than that of the conventional trellis coded unitary space-time modulation. The second design introduces constellations with multiple levels of amplitudes into the design of the multiple trellis coded orthogonal transmit scheme. For both designs, simulations show that multiple trellis coded orthogonal transmit schemes can achieve better performance than the conventional trellis coded unitarv space-time schemes.
文摘Space-time trellis codes can achieve the best tradeoff among bandwidth efficiency, diversity gain, constellation size and trellis complexity. In this paper, some optimum low rate space-time trellis codes are proposed. Performance analysis and simulation show that the low rate space-time trellis codes outperform space-time block codes concatenated with convolutional code at the same bandwidth efficiency, and are more suitable for the power limited wireless communication system.
文摘The known design criterions of Space-Time Trellis Codes （STFC） on slow Rayleigh fading channel are rank, determinant and trace criterion. These criterions are not advantageous not onlv in operation but also in performance. With classifying the error events of STTC, a new criterion was presented on slow Rayleigh fading channels. Basod on the criterion, an effective and straighttbrward multi-step method is proposed to ennstruet codes with better performance. This method can reduce the computation of search to small enough. Simulation results show that the codes searched by computer have the same or even better performance than the repored codes.
基金supported by Shanghai Municipal Government and Nokia
文摘Space time trellis coding （STTC） techniques have been proposed to achieve both diversity and coding gains in multiple input multiple output （MIMO） fading channels. But with more transmit antennas STTCs suffer from the design dificulty and complexity increasing. This paper proposes a scheme, named parallel concatenated space time trellis codes （PC-STTC）, to achieve the tradeoff between the performances and complexity of STTCs for a large number of transmit antennas. Simulation results and complexity comparison are provided to demonstrate the performance and superiority of the proposed scheme over conventional schemes in fast fading channels in low signal-to-noise ratio （SNR） regions. And an EXIT （extrinsic information transform） chart is given to analyze the iterative convergence of the proposed scheme. It shows that PC-STTC has better iterative convergence in low SNR regions.
文摘In this paper, STC with water-filling transmit power distribution in MISO system is proposed when the partial channel information feedback is possible, for example, at slow fading scenario. The performances of the water-filling STC including water-filling STTC and water-filling STBC are analyzed. Performance comparison of the Ungerboeck's 2/3 trellis coded 8PSK modulated 2-STBC and 2-STTCs with QPSK is given out in different channel correlation.
文摘Wireless sensor network （WSN） requires robust and efficient communication protocols to minimise delay and save energy. The lifetime of WSN can be maximised by selecting proper medium access control （MAC） scheme depending on the contention level of the network. The throughput of WSN however reduces due to channel fading effects even with the proper design of MAC protocol. Hence this paper proposes a new MAC scheme for enabling packet transmission using cooperative multi-input multi-output （MIMO） utilising space time codes（STC） such as space time block code （STBC）, space time trellis code （STTC） to achieve higher energy savings and lower delay by allowing nodes to transmit and receive information jointly. The performance of the proposed MAC protocol is evaluated in terms of transmission error probability, energy consumption and delay. Simulation results show that the proposed cooperative MIMO MAC protocol provides reliable and efficient transmission by leveraging MIMO diversity gains.
文摘In this paper we use trellis coded amplitude modulation (TC-AM) as models to analyze the receivers with intersymbol interference (ISI) under BPSK and π/4-QPSK modulations.Using the modified generating function and the weight profile function of the TC-AM,the bit error probability for both cases is evaluated in the sense of maximum likelihood decoding.The numerical result is given.
文摘Parallel concatenated spa ce time trellis code modulation, called Turbo STCM, can efficiently increase the coding gains of the space time codes. However, the complexity of the iterat iv e decoding restricts its application. This paper introduces a lower complex deco ding algorithm based on soft output Viterbi algorithm (SOVA) for Turbo STCM. S imulational results show that the new SOVA algorithm for the Turbo STCM outperf orms the original space time trellis code (STTC) by 4~6 dB. At the same time, compared with the Max Log MAP (maximum a posteriori) algorithm, the new scheme requires a lower complexity and approaches the performance of Turbo STCM decod ing w ith Max Log MAP.
文摘Two different set partitioning strategies used in Turbo TCM, UP （Ungerboeck Partitioning） and BP （Block Partitioning） are compared over Rayleigh fading channels. The performance of Turbo TCM with the two set partitioning strategies and different frame length over Rayleigh fading channels is evaluated. The simulation results of 8PSK and 8ASK modulation and some significant conclusions are also given in this paper.
基金supported by the National Natural Science Foundation of China (90604035)
文摘Coded overlapped code division multiplexing system with Turbo product structure （TPC-OVCDM） is introduced, and trellis coded modulation （TCM） code is employed as error correcting code for uncoded overlapped code division multiplexing （OVCDM） system. In such a scheme, row code and column code are TCM and OVCDM spreading code, respectively. Data bits are only encoded directly by TCM and transformed into a matrix. Each column of this matrix is then permuted by symbol interleaver before being encoded by OVCDM spreading code. During iterative decoding process in the receiver, two constituent decoders use symbol by symbol BCJR algorithm in the log domain. The order of decoding two sub-codes is determined by the encoding order. The proportion of TCM coding and OVCDM coding affects system performance. For fixed coding structure and symbol interleaver, the performance of TPC-OVCDM systems of different proportions of additive white Gaussian noise （AWGN） channel have been simulated. The results show that TPC-OVCDM system of reasonable proportion can achieve significant coding gain, compared with uncoded OVCDM system under the condition of same spectral efficiency at bit error rate （BER） level of 10^-5.
基金Supported by the National Natural Science Foundation of China(60673071)
文摘Let C be a free cyclic code over Zp^a and dim pC = k. In the paper, we prove that if the k characteristic generators of C are p-linearly independent then the corresponding nα- k characteristic generators of C^⊥ are p-linearly independent. We then show that to any trellis that can be constructed from k p-linearly independent characteristic generators of C, there exists a trellis for C^⊥ with the same state-complexity profile, which generalizes the conjecture of Koetter and Vardy to a free cyclic code over Zpo.
基金the Open Subject of the Important Labortary of the Modern Optical Technology of Jiangsu Provience(No.KJS0730)
文摘Propagation properties of polarized anisotropic crystals were investigated four-petal Gaussian beams along the optical axis of uniaxially Based on the paraxially vectorial theory of beam propagation analytic expressions of the diffraction light field larization properties of the diffracted four-petal were obtained. The effects of the anisotropy on the po- Gaussian beams have also been explained by numerical method. The results elucidate that the linear polarization state and the symmetry of the incident beams cannot be kept during propagation in anisotropic crystals.
基金the National Natural Science Foundation of China (No.10674183)the National"973"Project of China (No.2004CB719804)Ph.D.Degrees Foundation of Ministry of Education of China (No.20060558068).
文摘We derived the theoretical results of soliton interactions in optical fiber with super-Gaussian sliding-frequency filters. The results demonstrate that the interactions between optical fiber solitons can be effectively suppressed by super-Gaussian sliding-frequency filters. And the results also show that the super-Gaussian filter with sliding is more effective in suppressing soliton interactions than that without sliding.
