This paper evaluates at the various modulation and coding techniques suitable for adaptive data communication system. The techniques evaluated are applicable to HF spectrum. Examples of modulation and coding scheme th...
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This paper evaluates at the various modulation and coding techniques suitable for adaptive data communication system. The techniques evaluated are applicable to HF spectrum. Examples of modulation and coding scheme that are evaluated include PACTOR I, PACTOR II, PACTOR III, GTOR and STANAG 4285. Analysis of system performance is made in the presence of AWGN with future extension for multipath fading conditions. Comparison will be made based on the bit-error rate (BER), packet-error rate (PER) and the throughput. In addition, the effective data rate for all the schemes is compared with the Shannon capacity limit to ensure the optimal utilization of the given channel bandwidth. The modulation and coding scheme that meets all of the above requirements will be used for future adaptive data communication system.
GOFDM (generalized OFDM) has been proposed as a tradeoff solution between cyclic prefix single carrier (CP-SC) and OFDM system that can alleviate the peak to average power ratio (PAPR) problem of OFDM. In this paper, ...
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GOFDM (generalized OFDM) has been proposed as a tradeoff solution between cyclic prefix single carrier (CP-SC) and OFDM system that can alleviate the peak to average power ratio (PAPR) problem of OFDM. In this paper, a novel estimation method for the estimation of the received SNR of GOFDM signal that is required in the adaptive modulation and coding (AMC) is presented. The simulation results of the estimated SNR show excellent correlation with the analytical results. Furthermore, the received SNRs of the GOFDM exhibit repetition of as set values that can be clustered for modulation and coding scheme (MCS) allocation in group-based AMC. The paper also presents various performances of the proposed GOFDM with AMC and compares them with the corresponding performance of OFDM and CP-SC under same operating conditions.
We present an optimal Adaptive modulation and coding (AMC) policy that minimizes the transmission latency and modulation/coding switching cost across a finite-state Markovian fading channel. We formulate the optimal t...
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We present an optimal Adaptive modulation and coding (AMC) policy that minimizes the transmission latency and modulation/coding switching cost across a finite-state Markovian fading channel. We formulate the optimal tradeoff between the transmission latency and the modulation/coding switching cost as a stochastic shortest path Markov decision problem (MDP). By exploiting special structures of the formulated MDP and under certain sufficient conditions, we show that optimal modulation and coding selection policies are monotone in the state variables. These monotone optimal policies are computationally inexpensive to implement and are scalable in terms of channel and switching cost parameters. Numerical results confirm the monotonicity and threshold-based structure of the optimal MCS selection policies under the proposed sufficient conditions.
In this paper, we propose two backward adaptive coding algorithms based on a recently invented pre/post-filtered DPCM (Differential Pulse-Coded modulation) codec. The pre/post-filters and the predictor are adapted joi...
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In this paper, we propose two backward adaptive coding algorithms based on a recently invented pre/post-filtered DPCM (Differential Pulse-Coded modulation) codec. The pre/post-filters and the predictor are adapted jointly. Source statistics are assumed unknown a priori. One of the algorithms is based on power spectrum estimation, and the other gradient descent. Some properties of the algorithms are analyzed. Experiment results show that both algorithms achieve near-optimal rate-distortion performance, significantly outperforming the adaptive DPCM without adaptive pre/post-filtering.
This paper introduces a new approach to cooperative communications. Consider a system wherein two partner nodes cooperate to convey their data to a common destination, each not only transmitting its own “local” data...
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ISBN:
(纸本)9781424478903
This paper introduces a new approach to cooperative communications. Consider a system wherein two partner nodes cooperate to convey their data to a common destination, each not only transmitting its own “local” data but also acting as a relay for its partner, thereby effecting spatial diversity. In the proposed scheme, each partner interleaves local data with relayed data and convolutionally encodes the resulting interleaved bitstream prior to transmission; the other partner then uses its knowledge of the relayed data to prune edges from the code trellis, thereby decoding at a lower (more robust) rate. The destination observes two versions of each source's data - one transmitted as local information, the other as relayed information - and employs iterative decoding, in effect decoding the data as if it were encoded via a “distributed” turbo code. The resulting performance is superior to those of cooperation schemes based on time sharing and signal space superposition, and it generalizes the algebraic superposition scheme of Xiao et al.
Existing inter-frame interference (IFI) and intersymbol interference (ISI) mitigation schemes for noncoherent UWB Impulse Radio (UWB-IR) mainly focus on signal processing after nonlinear autocorrelation receiver (AcR)...
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Existing inter-frame interference (IFI) and intersymbol interference (ISI) mitigation schemes for noncoherent UWB Impulse Radio (UWB-IR) mainly focus on signal processing after nonlinear autocorrelation receiver (AcR) or energy detector (ED). Steering the wheel, a simple but effective IFI and ISI pre-mitigation scheme is proposed in this paper, which realizes IFI and ISI mitigation before ED. Block coded modulation is adopted and the pre-mitigation scheme relies on optimized block code design. The optimization jointly considers the signal interference-patterns before ED and the properties of codewords. Thanks to the matching among codes, interference and detection scheme, leaked signal energy is partially used for detection. IFI and ISI mitigation is thus realized. It is showed in simulations that distinct performance improvement is achieved under moderate IFI and ISI.
The multiplicative-additive finite-field matrix channel arises as an adequate model for linear network coding systems when links are subject to errors and erasures, and both the network topology and the network code a...
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ISBN:
(纸本)9781424479788;9781424479801
The multiplicative-additive finite-field matrix channel arises as an adequate model for linear network coding systems when links are subject to errors and erasures, and both the network topology and the network code are unknown. In a previous work we proposed a general construction of multishot codes for this channel based on the multilevel coding theory. Herein we apply this construction to the rank-metric space, obtaining multishot rank-metric codes which, by lifting, can be converted to codes for the aforementioned channel. We also adapt well-known encoding and decoding algorithms to the considered situation.
The amplify-and-forward (AF) and the decode-and-forward (DF) cooperative coded diversity is compared with the conventional receiver coded diversity in terms of the bit error rate (BER). The comparison assumes channel ...
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The amplify-and-forward (AF) and the decode-and-forward (DF) cooperative coded diversity is compared with the conventional receiver coded diversity in terms of the bit error rate (BER). The comparison assumes channel coding with non-binary modulations, and fast fading channels with path-loss attenuation proportional to the distance between nodes. Numerical results obtained by extensive computer simulations suggest that, for our path-loss system model, the AF diversity outperforms the receiver diversity provided that the relay is closer to the source and to the destination than the distance between the source and the destination. This condition can be satisfied more easily provided that there is more than one relay about the source, and for higher order modulations. In addition, the BER performance of the DF relaying is found to be more sensitive to the relay location than the BER performance of the AF relaying.
We present a new rate allocation scheme for multilevel coded modulation based on the minimization of the total block error rate (BLER). The proposed method uses affine code components and hard decision multistage deco...
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ISBN:
(纸本)9781424478903
We present a new rate allocation scheme for multilevel coded modulation based on the minimization of the total block error rate (BLER). The proposed method uses affine code components and hard decision multistage decoding. Exhaustive search for the rate allocation which minimizes the total BLER justifies the near-optimum performance of the introduced method in moderate to high SNRs. Compared to previous approaches this new rate allocation scheme can improve the performance of the system by 1 dB at BLER = 10 -6 for 16-QAM with Ungerboeck set partitioning. Interestingly, our results indicate that the optimum rate allocation is a function of the SNR. Finally, the performance of some specific codes are evaluated by simulation and union bounds to verify the theoretical results.
In order to realize very high throughput wireless local area network (WLAN) systems, which demand multi Gbps capacities/bitrates, the *** (Next generation WLAN standard at 60GHz band) is in the standardization process...
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ISBN:
(纸本)9781424425181;9781424425198
In order to realize very high throughput wireless local area network (WLAN) systems, which demand multi Gbps capacities/bitrates, the *** (Next generation WLAN standard at 60GHz band) is in the standardization process. To evaluate and select the proposed physical layer modulation and coding schemes in the standardization process, channel models for each specified usage model are required. In this paper, suitable impulse channel models for that purpose are proposed. Propagation measurements are carried out in a living room environment in the 60GHz band. To cover various usage cases, line-of-sight (LOS) and non-line-of-site (NLOS) scenarios and three different signal transmission polarization types are examined, and each channel model's parameters are extracted by statistical analysis. These channel models are useful in designing systems for millimeter-wave wireless communications.
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