A fiber-optic communication system employing a multistage bit-wise coded modulation scheme is considered as it enables the efficient utilization of higher-order modulation formats in combination with binary forward er...
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ISBN:
(纸本)9781467374316
A fiber-optic communication system employing a multistage bit-wise coded modulation scheme is considered as it enables the efficient utilization of higher-order modulation formats in combination with binary forward error correction (FEC) coding. Since modern FEC schemes employ soft-decision decoding, soft information on coded bits is required. In this paper, the decoding metric for the multistage bit-wise receiver structure is reviewed. Both numerical as well as experimental results are provided for the proposed decoding metrics using coded transmission over dispersion-unmanaged and dispersion-managed links.
coding and modulation schemes able to achieve unequal error protection are of interest for many applications in which parts of the payload must be differently protected against the noise. They are also useful for phys...
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ISBN:
(纸本)9781479985050
coding and modulation schemes able to achieve unequal error protection are of interest for many applications in which parts of the payload must be differently protected against the noise. They are also useful for physical layer security of transmissions over the broadcast channel with confidential messages. Classical design approaches aim at optimizing the performance over all the protection classes, independently of the separation between them. We instead propose a solution to improve the performance over the most protected bits, at the expense of performance over the least protected ones. This allows to design coded modulation schemes with largely unequal error protection. We also consider the use of high order modulations, and propose a technique to study the performance over each protection class in the asymptotic regime of infinite code length.
Binary physical-layer Raptor (PLR) codes are known to be capable of approaching the channel capacity over the binary-input additive white Gaussian noise (BIAWGN) channel efficiently. It is desired to apply PLR codes t...
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ISBN:
(纸本)9781509032556
Binary physical-layer Raptor (PLR) codes are known to be capable of approaching the channel capacity over the binary-input additive white Gaussian noise (BIAWGN) channel efficiently. It is desired to apply PLR codes to high order modulations to achieve good spectral efficiency. Herein we study the designs of using conventional PLR codes and protograph-based PLR codes by taking standard Gray-mapped 16QAM into consideration. Simulation results are presented to show the advantages of various designs.
We demonstrate a versatile method for creating state-dependent optical lattices by applying a magnetic field gradient modulated in time. This allows for tuning the relative amplitude and sign of the tunneling for diff...
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We demonstrate a versatile method for creating state-dependent optical lattices by applying a magnetic field gradient modulated in time. This allows for tuning the relative amplitude and sign of the tunneling for different internal states. We observe substantially different momentum distributions depending on the spin state of fermionic K40 atoms. Using dipole oscillations, we probe the spin-dependent band structure and find good agreement with theory. In situ expansion dynamics demonstrate that one state can be completely localized while others remain itinerant. A systematic study shows negligible heating and lifetimes of several seconds in the Hubbard regime.
Spontaneous pattern formation in a variety of spatially extended nonlinear systems always occurs through a modulation instability, sometimes called Turing instability: the homogeneous state of the system becomes unsta...
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Spontaneous pattern formation in a variety of spatially extended nonlinear systems always occurs through a modulation instability, sometimes called Turing instability: the homogeneous state of the system becomes unstable with respect to growing modulation modes. Therefore, the manipulation of the modulation instability is of primary importance in controlling and manipulating the character of spatial patterns initiated by that instability. We show that a spatio-temporal periodic modulation of the potential of spatially extended systems results in a modification of its pattern forming instability. Depending on the modulation character the instability can be partially suppressed, can change its spectrum (for instance the long wave instability can transform into short wave instability), can split into two, or can be completely eliminated. The latter result is of special practical interest, as it can be used to stabilize the intrinsically unstable system. The result bears general character, as it is shown here on a universal model of the Complex Ginzburg-Landau equation in one and two spatial dimensions (and time). The physical mechanism of the instability suppression can be applied to a variety of intrinsically unstable dissipative systems, like self-focusing lasers, reaction-diffusion systems, as well as in unstable conservative systems, like attractive Bose Einstein condensates.
In this article, we introduce a new spatial modulation (SM) transmission scheme using turbo trellis coding (TTC) for both antenna and symbol indexes. In spatial modulation scheme with trellis coding (SM-TC), the trans...
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ISBN:
(纸本)9781467361415
In this article, we introduce a new spatial modulation (SM) transmission scheme using turbo trellis coding (TTC) for both antenna and symbol indexes. In spatial modulation scheme with trellis coding (SM-TC), the transmitter encodes the information bits before selecting the transmit antenna and transmitted symbol indexes. The SM-TC scheme is a generalization of the turbo trellis coded SM (TTCSM) scheme, which encodes just the information bits used to select the transmit antenna index. The performances of the SM-TC scheme can be considerably enhanced by using parallel concatenated turbo coding. The new SM-TTC scheme combines the SM-TC transmission with conventional parallel turbo trellis-coded modulation (TTCM). The bit error rate (BER) performances are evaluated using simulations for PSK-SM-TTC transmissions over stationary Rayleigh, Rician, and spatially correlated (SC) fading channels with additive white Gaussian noise (AWGN). Simulation results reveal that the SM-TTC scheme performs better than the previous TTCSM scheme when transmitting over a SC fading channel, especially for a large number of receive antennas.
A joint design of modulation coding scheme for MIMO quasi-static fading systems is developed to provide high data rate and to minimize frame error probability. The main design idea is, at first, to decompose the MIMO ...
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ISBN:
(纸本)9781424455928;9781424455935
A joint design of modulation coding scheme for MIMO quasi-static fading systems is developed to provide high data rate and to minimize frame error probability. The main design idea is, at first, to decompose the MIMO system into multiple parallel SISO systems using singular value decomposition. Secondly, the design metric is obtained from an upperbound of pairwise error probability of the equivalent SISO systems. Thirdly, the joint design is obtained by finding the best asymmetric constellation and labeling of constellation points for a given baseline trellis structure of each SISO system through an exhaustive search. Simulation shows our joint design gives consistant performance gain.
Multicast video streaming in a wireless network allows a group of users to watch video and share the scarce bandwidth at the same time. Since the channel quality of each client may be different, it is difficult to con...
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Multicast video streaming in a wireless network allows a group of users to watch video and share the scarce bandwidth at the same time. Since the channel quality of each client may be different, it is difficult to control the perceived video quality in a multicast group. To ensure the whole group receives the data, some multicast mechanisms use the client with the worst channel quality as a reference to decide transmission speed. However, it may result in very low average video quality. This paper proposes a scheme, namely Scalable Video Multicast, to maximize the average perceived video quality in a multicast group in wireless networks. The proposed scheme uses the property that different modulation coding schemes provide different transmission speed and have different transmission distances. Scalable Video coding (SVC) and transmission rate scheduling are exploited to improve the average video quality perceived by the clients. The base layers of video frames provide basic visual quality to the clients. Rate scheduling applied on the enhancement layers improves the average visual quality. Simulations show that the proposed rate scheduling for SVC blocks can improve the average perceived video quality of multicast clients and outperforms other mechanisms in the literature.
The sliding-window superposition coding scheme aims to mitigate intercell interference at the physical layer by achieving the simultaneous decoding performance with point-to-point channel codes, low-complexity decodin...
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ISBN:
(纸本)9781479959532
The sliding-window superposition coding scheme aims to mitigate intercell interference at the physical layer by achieving the simultaneous decoding performance with point-to-point channel codes, low-complexity decoding, and minimal coordination overhead. The associated sliding-window coded modulation (SWCM) scheme can be readily implemented using standard off-the-shelf codes, such as the standard LTE turbo code, and tracks the information-theoretical performance guarantee of sliding-window superposition coding. This paper investigates how the basic SWCM scheme performs for the Ped-B fading interference channel model and proposes several improvements in transceiver design, such as soft decoding, input bit-mapping and layer optimization, and power control. Our enhanced SWCM scheme achieves the rates higher than those of the basic SWCM scheme by 10% to 20%, which already shows a significant gain over existing schemes that ignore modulation or coding information of interfering signals. This result confirms the potential of SWCM as a basic building block for physical-layer interference management in 5G and subsequent generations of cellular networks.
A joint modulation and coding scheme is proposed based on Rateless Codes and Vector OFDM systems to combat fading over doubly selective channels. A rateless encoder can generate potentially unlimited coded symbol. Vec...
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ISBN:
(纸本)9781479980925
A joint modulation and coding scheme is proposed based on Rateless Codes and Vector OFDM systems to combat fading over doubly selective channels. A rateless encoder can generate potentially unlimited coded symbol. Vector OFDM is a general transmission scheme, where OFDM and Single-Carrier systems can be seen as two extreme cases. The main focus of this paper is to design and analyze a Rateless Coded Vector OFDM scheme to obtain extra gain and improve the system performance. Firstly, we derive the lower bound of the decoding complexity of the block universal Raptor Codes and the upper bound of the probability to decode successfully in Binary Erasure Channels. Secondly, we analyze the joint scheme of Rateless Coded Vector OFDM with a novel proposition proposed, which reveals the impacts of the degree distribution on the system performance. According to the proposition, two practical Rateless Coded Vector OFDM methods are presented, which can achieve considerable joint Multipath-and-Doppler diversity gain and coded modulation gain to improve the reliability of the system. Finally, simulation results are demonstrated to validate the proposed scheme.
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