The Experts below are selected from a list of 19785 Experts worldwide ranked by ideXlab platform
Yuanan Liu - One of the best experts on this subject based on the ideXlab platform.
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ICC - Flexible Orthogonal Code for CDMA Based MIMO-OFDM Systems with Space-Time-Frequency Spreading
2008 IEEE International Conference on Communications, 2008Co-Authors: Yachen Wang, Peng Zhang, Junyang Shen, Siyang Liu, Yuanan LiuAbstract:We propose a novel spreading Code, called flexible-Orthogonal Code (FOC), for space-time-frequency spreading (STFS) scheme in Code division multiple access (CDMA) based multiple input multiple output (MIMO) Orthogonal frequency division multiplexing (OFDM). The goal of our design is to obtain an improved bit-error rate (BER) performance without loss of bandwidth efficiency. We make use of multiple antennas to achieve space diversity and balanced signal to interference and noise ratio (SINR) among users on each subscriber device. The proposed Code exhibits length flexibility, which breaks up the "power of two" constraint in spreading factor. Our results indicate that the proposed Code improves overall performance of the system, by exploiting both space diversity and SINR balancing. The flexibility in Code length also results in high spectral efficiency.
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ICC - Full Diversity Spreading Code for Downlink Space-Time-Frequency Spreading CDMA
2008 IEEE International Conference on Communications, 2008Co-Authors: Siyang Liu, Yachen Wang, Feifei Wang, Ranran Zhang, Yuanan LiuAbstract:Recently proposed downlink space-time-frequency spreading CDMA (STFS-CDMA) is investigated in this paper. By analyzing, a spreading Code design criterion of it is derived. From the criterion, we can see that the original two classes of spreading Code adopted in STFS-CDMA, Walsh-Hadamard Code (WHC) and double-Orthogonal Code (DOC), both can not always achieve the full space and frequency diversity. Then, a novel spreading Code, zero padded rotary FFT Code (ZPRFC), is proposed. Compared with WHC Coded STFS-CDMA (WHC-STFS-CDMA) and DOC Coded STFS-CDMA (DOC-STFS-CDMA), the novel ZPRFC Coded STFS-CDMA (ZPRFC-STFS-CDMA) can obtain the full space and frequency diversity at the cost of the reduction of the number of supporting users.
Yachen Wang - One of the best experts on this subject based on the ideXlab platform.
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ICC - Flexible Orthogonal Code for CDMA Based MIMO-OFDM Systems with Space-Time-Frequency Spreading
2008 IEEE International Conference on Communications, 2008Co-Authors: Yachen Wang, Peng Zhang, Junyang Shen, Siyang Liu, Yuanan LiuAbstract:We propose a novel spreading Code, called flexible-Orthogonal Code (FOC), for space-time-frequency spreading (STFS) scheme in Code division multiple access (CDMA) based multiple input multiple output (MIMO) Orthogonal frequency division multiplexing (OFDM). The goal of our design is to obtain an improved bit-error rate (BER) performance without loss of bandwidth efficiency. We make use of multiple antennas to achieve space diversity and balanced signal to interference and noise ratio (SINR) among users on each subscriber device. The proposed Code exhibits length flexibility, which breaks up the "power of two" constraint in spreading factor. Our results indicate that the proposed Code improves overall performance of the system, by exploiting both space diversity and SINR balancing. The flexibility in Code length also results in high spectral efficiency.
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ICC - Full Diversity Spreading Code for Downlink Space-Time-Frequency Spreading CDMA
2008 IEEE International Conference on Communications, 2008Co-Authors: Siyang Liu, Yachen Wang, Feifei Wang, Ranran Zhang, Yuanan LiuAbstract:Recently proposed downlink space-time-frequency spreading CDMA (STFS-CDMA) is investigated in this paper. By analyzing, a spreading Code design criterion of it is derived. From the criterion, we can see that the original two classes of spreading Code adopted in STFS-CDMA, Walsh-Hadamard Code (WHC) and double-Orthogonal Code (DOC), both can not always achieve the full space and frequency diversity. Then, a novel spreading Code, zero padded rotary FFT Code (ZPRFC), is proposed. Compared with WHC Coded STFS-CDMA (WHC-STFS-CDMA) and DOC Coded STFS-CDMA (DOC-STFS-CDMA), the novel ZPRFC Coded STFS-CDMA (ZPRFC-STFS-CDMA) can obtain the full space and frequency diversity at the cost of the reduction of the number of supporting users.
Siyang Liu - One of the best experts on this subject based on the ideXlab platform.
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ICC - Flexible Orthogonal Code for CDMA Based MIMO-OFDM Systems with Space-Time-Frequency Spreading
2008 IEEE International Conference on Communications, 2008Co-Authors: Yachen Wang, Peng Zhang, Junyang Shen, Siyang Liu, Yuanan LiuAbstract:We propose a novel spreading Code, called flexible-Orthogonal Code (FOC), for space-time-frequency spreading (STFS) scheme in Code division multiple access (CDMA) based multiple input multiple output (MIMO) Orthogonal frequency division multiplexing (OFDM). The goal of our design is to obtain an improved bit-error rate (BER) performance without loss of bandwidth efficiency. We make use of multiple antennas to achieve space diversity and balanced signal to interference and noise ratio (SINR) among users on each subscriber device. The proposed Code exhibits length flexibility, which breaks up the "power of two" constraint in spreading factor. Our results indicate that the proposed Code improves overall performance of the system, by exploiting both space diversity and SINR balancing. The flexibility in Code length also results in high spectral efficiency.
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ICC - Full Diversity Spreading Code for Downlink Space-Time-Frequency Spreading CDMA
2008 IEEE International Conference on Communications, 2008Co-Authors: Siyang Liu, Yachen Wang, Feifei Wang, Ranran Zhang, Yuanan LiuAbstract:Recently proposed downlink space-time-frequency spreading CDMA (STFS-CDMA) is investigated in this paper. By analyzing, a spreading Code design criterion of it is derived. From the criterion, we can see that the original two classes of spreading Code adopted in STFS-CDMA, Walsh-Hadamard Code (WHC) and double-Orthogonal Code (DOC), both can not always achieve the full space and frequency diversity. Then, a novel spreading Code, zero padded rotary FFT Code (ZPRFC), is proposed. Compared with WHC Coded STFS-CDMA (WHC-STFS-CDMA) and DOC Coded STFS-CDMA (DOC-STFS-CDMA), the novel ZPRFC Coded STFS-CDMA (ZPRFC-STFS-CDMA) can obtain the full space and frequency diversity at the cost of the reduction of the number of supporting users.
Lizhong Zheng - One of the best experts on this subject based on the ideXlab platform.
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writing on fading paper dirty tape with little ink wideband limits for causal transmitter csi
IEEE Transactions on Information Theory, 2012Co-Authors: Shashi Borade, Lizhong ZhengAbstract:A wideband Rayleigh fading channel is considered with causal channel state information (CSI) at the transmitter and no receiver CSI. A simple Orthogonal Code with energy detection rule at the receiver (similar to pulse position modulation in IEEE Trans. Inf. Theory, vol. 46, no. 4, Apr. 2000 and IEEE Trans. Inf. Theory, vol. 52 no. 5, May 2006) is shown to achieve the capacity of this channel in the wideband limit. This strategy transmits energy only when the channel gain exceeds a threshold, hence only needs causal transmitter CSI. In the wideband limit, this capacity without any receiver CSI is the same as the capacity with full receiver CSI, which is proportional to the logarithm of the bandwidth. Similar threshold-based pulse position modulation is shown to achieve the capacity per unit cost of the dirty-tape channel (dirty paper channel with causal transmitter CSI and no receiver CSI), which equals its capacity per unit cost with full receiver CSI. Then, a general discrete channel with i.i.d. states is considered. Each input has an associated cost and a zero cost input “0” exists. The channel state is assumed to be known at the transmitter in a causal manner. Capacity per unit cost is found for this channel and a simple Orthogonal Code is shown to achieve this capacity. Later, a novel Orthogonal coding scheme is proposed for the case of causal transmitter CSI and a condition for equivalence of capacity per unit cost for causal and noncausal transmitter CSI is derived.
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writing on fading paper and causal transmitter csi
International Symposium on Information Theory, 2006Co-Authors: Shashi Borade, Lizhong ZhengAbstract:1 A wideband fading channel is considered with causal channel state information (CSI) at the transmitter and no receiver CSI. A simple Orthogonal Code with energy detection rule at the receiver is shown to achieve the capacity of this channel in the limit of large bandwidth. This Code transmits energy only when the channel gain is large enough. In this limit, this capacity without any receiver CSI is the same as the capacity with full receiver CSI?a phenomenon also true for dirty paper coding. For Rayleigh fading, this capacity (per unit time) is proportional to the logarithm of the bandwidth. Our coding scheme is motivated from the Gel'fand-Pinsker and dirty paper coding. Nonetheless, our scheme requires only causal transmitter CSI (CSIT) in contrast with Gel'fand-Pinsker and dirty paper coding, which require non-causal CSIT. A general discrete channel with i.i.d. states is considered later. Each input has an associated cost and a zero cost input "0" exists. The channel state is known at the transmitter in a causal manner. Capacity per unit cost is found for this channel and a simple Orthogonal Code is shown to achieve it. Later, a novel Orthogonal coding scheme is proposed for the case of causal CSIT and a condition for equal capacity per unit cost with causal and non-causal CSIT is derived.
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writing on fading paper and causal transmitter csi
arXiv: Information Theory, 2005Co-Authors: Shashi Borade, Lizhong ZhengAbstract:A wideband fading channel is considered with causal channel state information (CSI) at the transmitter and no receiver CSI. A simple Orthogonal Code with energy detection rule at the receiver (similar to [6]) is shown to achieve the capacity of this channel in the limit of large bandwidth. This Code transmits energy only when the channel gain is large enough. In this limit, this capacity without any receiver CSI is the same as the capacity with full receiver CSI--a phenomenon also true for dirty paper coding. For Rayleigh fading, this capacity (per unit time) is proportional to the logarithm of the bandwidth. Our coding scheme is motivated from the Gel'fand-Pinsker [2,3] coding and dirty paper coding [4]. Nonetheless, for our case, only causal CSI is required at the transmitter in contrast with dirty-paper coding and Gel'fand-Pinsker coding, where non-causal CSI is required. Then we consider a general discrete channel with i.i.d. states. Each input has an associated cost and a zero cost input "0" exists. The channel state is assumed be to be known at the transmitter in a causal manner. Capacity per unit cost is found for this channel and a simple Orthogonal Code is shown to achieve this capacity. Later, a novel Orthogonal coding scheme is proposed for the case of causal transmitter CSI and a condition for equivalence of capacity per unit cost for causal and non-causal transmitter CSI is derived. Finally, some connections are made to the case of non-causal transmitter CSI in [8].
M Sawahashi - One of the best experts on this subject based on the ideXlab platform.
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multipath interference canceller for high speed packet transmission with adaptive modulation and coding scheme in w cdma forward link
IEEE Journal on Selected Areas in Communications, 2002Co-Authors: Kenichi Higuchi, A Fujiwara, M SawahashiAbstract:This paper proposes a multipath interference canceller (MPIC) associated with Orthogonal Code-multiplexing that achieves much higher peak throughput than 2 Mbit/s with adaptive data modulation for high-speed packet transmission in the wideband direct sequence-Code division multiple access (W-CDMA) forward link, and evaluates its throughput performance by computer simulation. The simulation results elucidate that sufficient multipath interference (MPI) suppression is achieved by a four-stage MPIC with 6-12 Orthogonal Code-multiplexing using one iterative channel estimation with pilot and decision feedback data symbols and further that the interference rejection weight control according to the number of observed multipaths is effective in improving the throughput. It is also demonstrated that MPIC exhibits a superior MPI suppression effect to a chip equalizer in the lower received signal energy per bit-to-background noise spectrum density (E/sub b//N/sub 0/) channel around 0-3 dB owing to the successive channel estimation at each stage. We show that the maximum peak throughput using MPIC is approximately 2.1 fold that without MPIC in a two-path and three-path Rayleigh fading channel and that the peak throughput of 8.0 Mbit/s is achieved using 64 QAM data modulation in a two-path fading channel within a 5 MHz bandwidth. Furthermore, the required average E/sub b//N/sub 0/ for satisfying the same throughput with MPIC is decreased by more than 2.0 dB.
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multipath interference canceller for high speed packet transmission with adaptive modulation and coding scheme in w cdma forward link
Vehicular Technology Conference, 2001Co-Authors: Kenichi Higuchi, A Fujiwara, M SawahashiAbstract:This paper proposes a multipath interference canceller (MPIC) associated with Orthogonal Code-multiplexing with Orthogonal variable spreading factor (OVSF) channelization Codes that achieves high throughput performance with adaptive data modulation in multipath fading channels in the W-CDMA forward link, and evaluates its throughput performance by computer simulation. The simulation results elucidate that sufficient multipath interference suppression is achieved by a four-stage MPIC with 6-12 Orthogonal Code-multiplexing using one iterative channel estimation with pilot and decision feedback data symbols hard-decided after RAKE combining. We show that the maximum peak throughput using MPIC is approximately 2.1 fold that without MPIC in a 2-path Rayleigh fading channel and that the peak throughput of 8.0 Mbps is achieved using 64QAM data modulation within a 5-MHz bandwidth. Furthermore, the required average E/sub b//N/sub 0/ for satisfying the same throughput with MPIC is decreased by more than 2.0 dB.
