Rolling accidents often happen on the tight curves, so road-to-vehicle communication is required. In this paper we apply visible light communication to road-to-vehicle communication and propose a tight curve warning s...
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ISBN:
(纸本)9781479914128;9781479914111
Rolling accidents often happen on the tight curves, so road-to-vehicle communication is required. In this paper we apply visible light communication to road-to-vehicle communication and propose a tight curve warning system. We use the hierarchical coding of FSK because a receiver can receive both low frequency data and high frequency data when it is close to the sender, and it can receive only low frequency data when it is far away from the sender. We made a 1/32 scale prototype model and the experimental results show its ability to distinguish the communication distance from the frequency. The car on our prototype system put on its brakes 2 m from an LED using 16.6 kHz.
To improve reliability of packet transmission, wireless communication systems use appropriate retransmission schemes based on characteristics of each protocol layer. In each protocol layer, retransmission schemes oper...
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ISBN:
(纸本)9781467357425;9781467357401
To improve reliability of packet transmission, wireless communication systems use appropriate retransmission schemes based on characteristics of each protocol layer. In each protocol layer, retransmission schemes operate without cooperation of other layers. However, to improve system performance over wireless channel, a retransmission scheme of each protocol layer can use information on other protocol layers. For this reason, the cross-layer retransmission schemes recently have been proposed. The cross-layer retransmission scheme that is an retransmission scheme combined with adaptive modulation and coding (AMC) scheme can improve average spectral efficiency by considering both wireless channel state and parameters of a retransmission scheme. However, conventional researches concentrate on improving system performance over wireless channel and the end-to-end performance is not considered. It may be difficult to find an appropriate cross-layer retransmission scheme and system parameters for each service class. Thus, the end-to-end performance should be analyzed to decide whether the cross-layer retransmission schemes and parameters are suitable for each service class. In this paper, we analyze the end-to-end performance of wireless communication system using a cross-layer retransmission scheme and evaluate the system performance such as spectral efficiency, packet error rate (PER), and end-to-end throughput on transport layer. From the evaluation results, it can be seen that the end-to-end throughput of the hybrid automatic repeat request (HARQ) scheme combined with AMC is superior to that of automatic repeat request (ARQ) combined with AMC.
In this work, we investigate the power allocation (PA) problem aimed at minimizing the users' packet error rate (PER) over a noncooperative link, i.e., a link where the set of users, employing packet-oriented bit-...
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ISBN:
(纸本)9781467331227
In this work, we investigate the power allocation (PA) problem aimed at minimizing the users' packet error rate (PER) over a noncooperative link, i.e., a link where the set of users, employing packet-oriented bit-interleaved coded (BIC) orthogonal frequency division multiplexing (OFDM) systems, compete for the same bandwidth. For these kind of systems, the PER is not available in closed-form, but a very efficient solution is offered by the effective SNR mapping (ESM) technique. This method allows each user to evaluate a single scalar value, the effective SNR (ESNR), accounting for all the SNIRs experienced over the active subcarriers, and to univocally map it into a PER value. Thus, in order to derive a decentralized strategy allowing each user to minimize its own PER, the problem is described as a strategic game, called min-PER game, with the set of player, utilities and strategies represented by the competitive users, the ESNRs and the set of feasible power allocations, respectively. We will show both the existence of at least one Nash Equilibrium (NE) for the min-PER game and its equivalence with a Nonlinear Variational Inequality (NVI) problem. Finally, relying on the theory of contraction mappings, we will derive a distributed algorithm to reach the NE of the game.
A new bit-interleaved polar coded modulation (BIPCM) scheme is proposed. To reduce the construction complexity, the simplest kernel matrix for channel polarization is adopted. And auxiliary virtual channels with zero-...
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ISBN:
(纸本)9781467362337
A new bit-interleaved polar coded modulation (BIPCM) scheme is proposed. To reduce the construction complexity, the simplest kernel matrix for channel polarization is adopted. And auxiliary virtual channels with zero-capacities are introduced to adapt different modulation orders. The underlying polar codes are efficiently constructed by calculating the Bhattacharyya parameters of equivalent binary-input erasure channels (BECs) rather than computing-expensive density evolution. Further, to avoid exhaustive searching, an empirically good channel mapping scheme is provided. Compared with the existing BIPCM schemes, the proposed scheme has a lower construction complexity and can achieve a better performance. With cyclic redundancy check (CRC) aided decoding algorithms, the block error rate (BLER) performance of our proposed BIPCM scheme can outperform the turbo coded modulation scheme used in WCDMA (Wideband Code Division Multiple Access) wireless communication system by up to 0.5dB.
We consider a signaling format where information is modulated via a superposition of independent data streams. Each data stream is formed by replication and permutation of encoded information bits. The relations betwe...
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ISBN:
(纸本)9781479904464
We consider a signaling format where information is modulated via a superposition of independent data streams. Each data stream is formed by replication and permutation of encoded information bits. The relations between data bits and modulation symbols transmitted over the channel can be represented in the form of a sparse graph. The modulated streams are transmitted with time offsets enabling spatial coupling of the sparse modulation graphs. We prove that iterative demodulation based on symbol estimation and interference cancellation followed by parallel error correction decoding is a universal multiple access technique which achieves the entire capacity region of the additive white Gaussian noise (AWGN) multiple access channel.
We experimentally investigate the characteristics of 126-Gb/s coded 6PolSK-QPSK signals in the nonlinear transmission regime and demonstrate that required OSNR improvement is increasing with fiber-launch power due to ...
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ISBN:
(纸本)9781557529626;9781479904570
We experimentally investigate the characteristics of 126-Gb/s coded 6PolSK-QPSK signals in the nonlinear transmission regime and demonstrate that required OSNR improvement is increasing with fiber-launch power due to coded modulation as well as digital back propagation.
We discuss the design of practical codes for large-alphabet secret key distribution, motivated by the application of high-dimensional quantum key distribution. We introduce and study a simple scheme called layered sch...
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ISBN:
(纸本)9781467346481
We discuss the design of practical codes for large-alphabet secret key distribution, motivated by the application of high-dimensional quantum key distribution. We introduce and study a simple scheme called layered scheme, which can be treated as a variant of coded modulation. The idea of layered schemes is to first split the observed large-alphabet symbols into bit layers, and to then encode all the bit layers either independently or jointly using binary codes. The channels that we are interested in are more general than the AWGN channels or Rayleigh fading channels studied in coded modulation. We present and compare different implementations of layered schemes, i.e., based on independent parallel encoding or joint encoding, and we investigate different approaches in how to map large-alphabet symbols into bit layers. Both theoretical analyses and simulation results show that layered schemes have good performances on q-ary channels such as uniform-error channels and limited-magnitude-error channels.
This paper present the detailed design and the algorithm for forward link ACM(Adaptive coding & modulation) system to improve the link availability and system throughput in satellite communication services. To imp...
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ISBN:
(纸本)9781467313636;9781467313612
This paper present the detailed design and the algorithm for forward link ACM(Adaptive coding & modulation) system to improve the link availability and system throughput in satellite communication services. To implement ACM system, the channel prediction and MODCOD decision methods is simulated. The channel prediction result shows that the 99% of predicted values in LMS(Least Mean Square) algorithm is within 3dB. Also this paper proposes the appropriate system architecture for ACM transmission.
This paper extends Average Threshold Crossing (ATC) wireless transmission to a multi-channel case by using Address-Event Representation (AER) as the way to convey information. This is encoded in the timings of the tra...
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ISBN:
(纸本)9781479900411;9781479900398
This paper extends Average Threshold Crossing (ATC) wireless transmission to a multi-channel case by using Address-Event Representation (AER) as the way to convey information. This is encoded in the timings of the transmitted packets which in turn carry the identifier of the event source. By integrating a Impulse Radio-Ultra Wide Band (IR-UWB) and choosing the proper protocol and modulation, we can aim to minimize the power consumption and provide error detection. The whole system, fully asynchronous, has been implemented in a full-custom chip;besides having multiple independent inputs, it can be configured both to deploy a multi-chip system (with a single receiver) and to optimize wireless transmission parameters. The paper concludes with additional theoretical simulations on the ATC scheme to justify further analyses for our specific application area which regards movement recognition.
In wireless sensor networks, nodes can retransmit their neighbours' packets to provide redundancy and decrease packet error rate. However, this comes at the expense of increased energy consumption in the cooperati...
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ISBN:
(纸本)9781467363372
In wireless sensor networks, nodes can retransmit their neighbours' packets to provide redundancy and decrease packet error rate. However, this comes at the expense of increased energy consumption in the cooperating nodes. Cooperation between nodes in routing data is a necessity in sensor networks. This work exploits features of UWB-IR modulations to create redundancy in wireless sensor networks. We introduce a physical layer coding framework for UWB-IR and compare it with conventional UWB-IR modulation in terms of energy usage. Simulation results show that the proposed methods can decrease the energy usage of the nodes while enhancing packet error rate performance of the system.
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