Low-earth-orbit (LEO) satellite-terrestrial network (LSTN) is expected to play a significant role in the next-generation wireless networks (6G), providing global coverage and facilitating various 6G applications. Howe...
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ISBN:
(纸本)9798350378412
Low-earth-orbit (LEO) satellite-terrestrial network (LSTN) is expected to play a significant role in the next-generation wireless networks (6G), providing global coverage and facilitating various 6G applications. However, the high dynamics of channel state information (CSI) in LSTN have posed challenges to modulation and coding schemes (MCS), which adversely affects the correctness of data transmission and the quality of service (QoS) expected by users. To enhance the communication reliability of LSTN, in this paper, we investigate the adaptive coding and modulation (ACM) method under the digital video broadcasting (DVB) standards. We first establish a channel model and then introduce an ACM method involving channel state estimation, channel state prediction, and MCS switching. Subsequently, the least squares (LS) algorithm is leveraged for channel estimation and we propose an ARIMA-Bidirectional Long Short-Term Memory (AB-LSTM) algorithm specifically for forecasting time-series signal-to-noise ratio (SNR) values for precise channel prediction. Then MCS switching is conducted based on the predicted SNR and switching threshold based on DVB standards. We conduct extensive simulations to show that our proposed algorithms can achieve higher estimation and prediction accuracy, and the introduced ACM method can effectively optimize the usage of channel capacity.
We introduce adaptive coding and modulation (ACM) to direct-detection passive optical networks (PONs) operating beyond 10 Gb/s per wavelength to allow each user to transmit at the highest possible bit rate and improve...
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We introduce adaptive coding and modulation (ACM) to direct-detection passive optical networks (PONs) operating beyond 10 Gb/s per wavelength to allow each user to transmit at the highest possible bit rate and improve network reliability. Current fixed-rate PONs must allocate significant power margin to ensure reliable long-term operation over channels that vary over time and between users. Introducing adaptive-rate transceivers with ACM is a promising low-cost solution to increasing the overall capacity of optical access networks. The proposed ACM scheme uses two-, three-, or four-level pulse-amplitude modulation (2-, 3-, or 4-PAM) at a fixed symbol rate with direct detection and low-density parity check (LDPC) codes derived from a mother code by shortening and puncturing, decoded using fixed-initialization normalized min-sum decoding. The scheme supports received optical powers spanning a 10-dB range at bit rates of 20-54 Gb/s. In a PON with 64 users transmitting at a symbol rate of 30 Gbaud and a maximum transmission distance of 25 km, the ACM scheme demonstrates more than 3 dB improvement in overall optical power budget. For a fixed margin, ACM can increase throughput up to 60% compared to fixed-rate transmission, from 25 Gb/s to 39.7 Gb/s, or from 37.5 Gb/s to over 50 Gb/s, depending on the received optical power.
In this chapter, we investigate a DVB-RCS2-based satellite communication system consisting of a gateway, a satellite, and a return channel satellite terminal (RCST). We formulate an optimization problem to maximize th...
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ISBN:
(纸本)9781839531460;9781839531453
In this chapter, we investigate a DVB-RCS2-based satellite communication system consisting of a gateway, a satellite, and a return channel satellite terminal (RCST). We formulate an optimization problem to maximize the transmission rate of the system. To solve the problem, we propose an adaptive coding and modulation (ACM) and power control scheme for return link transmission based on the return channel condition and power headroom of the RCST. Simulation results show that the proposed ACM and power control scheme increases the transmission rate as the transmit power of RCST and satellite increases or the power headroom of RCST increases.
The radiocommunication part of the International Telecommunication Union (ITU-R) establishes the standards for wireless communications. Recommendation ITU-R S.1062 specifies the performance objectives for satellite co...
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The radiocommunication part of the International Telecommunication Union (ITU-R) establishes the standards for wireless communications. Recommendation ITU-R S.1062 specifies the performance objectives for satellite communication systems providing constant bit rate service. However, this is not applicable to most modern satellite communication systems utilizing adaptive coding and modulation (ACM) schemes to compensate for channel impairments, especially for systems operating in high frequency bands. For this reason, ITU-R recently developed Recommendation ITU-R S.2131 that is suitable for satellite systems with ACM. The developed Recommendation provides a method to determine performance objectives for satellite systems using ACM. Two possible objective parameters are presented, including packet error rate and spectral efficiency. This paper presents the standardization process, and the background used to establish new performance objectives. In addition, interpretations of the objectives are given by using estimation results for two different propagation characteristics.
In this study, a field-programmable gate array (FPGA) based high rate transmitter is developed for low earth orbit satellite communication links using adaptive coding and modulation (ACM) techniques. The developed tra...
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ISBN:
(纸本)9781728181615
In this study, a field-programmable gate array (FPGA) based high rate transmitter is developed for low earth orbit satellite communication links using adaptive coding and modulation (ACM) techniques. The developed transmitter structure is modeled in MATLAB. Then, the MATLAB model is taken as reference for developing an FPGA design. This design is implemented on Xilinx Kintex Ultrascale XCKU060 FPGA which provides high performance and whose space grade model will be on product line in December 2020. It is shown that the developed transmitter structure can reach a spectral efficiency of 7.068 bits per second per Hertz (bps/Hz) with a code rate of 0.8889 in the highest rate mode. The implemented FPGA design of the transmitter structure can support input data rates from 50.7225 megabits per second (Mbps) to 530.1 Mbps with a baud rate of 75 mega symbol per second (Msps) and a sampling rate of 300 mega sample per second (MSps) at the output.
In order to meet the demands of "Internet above the clouds," we propose a multiple-antenna aided adaptive coding and modulation (ACM) for aeronautical communications. The proposed ACM scheme switches its cod...
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In order to meet the demands of "Internet above the clouds," we propose a multiple-antenna aided adaptive coding and modulation (ACM) for aeronautical communications. The proposed ACM scheme switches its coding and modulation mode according to the distance between the communicating aircraft, which is readily available with the aid of the airborne radar or the global positioning system. We derive an asymptotic closed-form expression of the signal-to-interference-plus-noise ratio (SINR) as the number of transmitting antennas tends to infinity, in the presence of realistic co-channel interference and channel estimation errors. The achievable transmission rates and the corresponding mode-switching distance-thresholds are readily obtained based on this closed-form SINR formula. Monte-Carlo simulation results are used to validate our theoretical analysis. For the specific example of 32 transmit antennas and four receive antennas communicating at a 5-GHz carrier frequency and using 6-MHz bandwidth, which are reused by multiple other pairs of communicating aircraft, the proposed distance-based ACM is capable of providing as high as 65.928-Mb/s data rate when the communication distance is less than 25 km.
We propose a regularized zero-forcing transmit precoding (RZF-TPC)-aided and distance-based adaptive coding and modulation (ACM) scheme to support aeronautical communication applications, by exploiting the high spectr...
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We propose a regularized zero-forcing transmit precoding (RZF-TPC)-aided and distance-based adaptive coding and modulation (ACM) scheme to support aeronautical communication applications, by exploiting the high spectral efficiency of the large-scale antenna arrays and link adaption. Our RZF-TPC-aided and distance-based ACM scheme switches its mode according to the distance between the communicating aircraft. We derive the closed-form asymptotic signal-to-interference-plus-noise ratio (SINR) expression of the RZF-TPC for the aeronautical channel, which is Rician, relying on a non-centered channel matrix that is dominated by the deterministic line-of-sight component. The effects of both realistic channel estimation errors and of the co-channel interference are considered in the derivation of this approximate closed-form SINR formula. Furthermore, we derive the analytical expression of the optimal regularization parameter that minimizes the mean square detection error. The achievable throughput expression based on our asymptotic approximate SINR formula is then utilized as the design metric for the proposed RZF-TPC-aided and distance-based ACM scheme. Monte-Carlo simulation results are presented for validating our theoretical analysis as well as for investigating the impact of the key system parameters. The simulation results closely match the theoretical results. In the specific example that two communicating aircrafts fly at a typical cruising speed of 920km/h, heading in opposite direction over the distance up to 740km taking a period of about 24 min, the RZF-TPC-aided and distance-based ACM is capable of transmitting a total of 77 GB of data with the aid of 64 transmit antennas and four receive antennas, which is significantly higher than that of our previous eigen-beamforming transmit precoding-aided and distance-based ACM benchmark.
In order to meet the high-speed downlink data transmission requirements of medium and low-orbit remote sensing satellites, higher spectrum efficiency is achieved under limited frequency band resources. This paper prop...
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ISBN:
(纸本)9781538645093
In order to meet the high-speed downlink data transmission requirements of medium and low-orbit remote sensing satellites, higher spectrum efficiency is achieved under limited frequency band resources. This paper proposes an adaptive coding and modulation technique aiming at the problem of waste of link margin in the traditional data transmission mode. It can realize full utilization of link margin and improve spectrum efficiency under the premise of reliable transmission. Through link calculation and simulation verification, the spectrum utilization rate of the remote sensing data transmission under adaptive mode is 1.8 times that of the traditional constant coding and modulation mode.
in this paper, an adaptive coding and modulation (ACM) technique is introduced in an attempt to maximize the channel throughout. This technique suggests five different pairs of coding and modulation techniques, starti...
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ISBN:
(纸本)9781538627358
in this paper, an adaptive coding and modulation (ACM) technique is introduced in an attempt to maximize the channel throughout. This technique suggests five different pairs of coding and modulation techniques, starting from low modulation orders and code rates going through higher values. Simulation over additive white Gaussian noise (AWGN) of the physical layer of the system is performed using M-phase shift keying (M-PSK) modulation and convolutional codes with soft Viterbi decoding algorithm. In addition, the channel throughput for each modulation and coding pair is obtained using specific packet retransmission mechanism. An algorithm for adaptive coding and modulation is developed and the overall throughout of the adaptive system is determined with respect to the received E-b/N-o values.
In this paper, we address the coding problem for adaptivecoding and modulator indicators in communication systems where users are divided into several classes according to their channel quality. Two novel methods are...
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In this paper, we address the coding problem for adaptivecoding and modulator indicators in communication systems where users are divided into several classes according to their channel quality. Two novel methods are described to construct codebooks with variable length codewords forsuch an application. The proposed constructions satisfy all constraints of the system model, showing considerable gain in both the maximal and average length of codebook with respect to the current state of the art. The methodology includes a systematic way for constructing variable length codebooks where codewords are not uniformly distributed in the space, and thus, some codewords are more protected than others. The proposed construction can be easily adapted, by zero padding, to obtain a fixed block-length code, with length equal to the maximal length of the designed variable-length code but still smaller than that of the best state-of-the-art code. Copyright (c) 2015 John Wiley & Sons, Ltd.
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