In Cognitive Radio (CR) networks, it is common that the spectrum holes are too narrow to support high-speed communications. Discontinuous Orthogonal Frequency Division Multiplexing (DOFDM) is a good way for a secondar...
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ISBN:
(纸本)9781612849287
In Cognitive Radio (CR) networks, it is common that the spectrum holes are too narrow to support high-speed communications. Discontinuous Orthogonal Frequency Division Multiplexing (DOFDM) is a good way for a secondary user to access several spectrum fragments simultaneously with one Radio Front (RF). In this paper, a novel Channel Characteristic Aware Spectrum Aggregation (CCASA) algorithm which uses DOFDM to aggregation spectrum fragments with only one radio front is proposed in order to increase the overall throughput of a CR network. By combining adaptive modulation and coding (AMC) and spectrum aggregation, the good subcarriers are assigned to the specific secondary users in CCASA algorithm thus achieving a better channel efficiency. Different bandwidth requirement and aggregation limitation of secondary users are both considered in this algorithm while maintaining a fairly low computational complexity. The simulation results show that CCASA achieves a bigger total throughput than existing aggregation algorithms.
The fourth industrial revolution will significantly improve the level of informatization and intelligence of the industry by building a smart factory. As an essential part of the smart factory, industrial communicatio...
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ISBN:
(数字)9781665455442
ISBN:
(纸本)9781665455442
The fourth industrial revolution will significantly improve the level of informatization and intelligence of the industry by building a smart factory. As an essential part of the smart factory, industrial communication systems face rigorous challenges. On the one hand, many smart factory applications demand data delivery with ultra-high reliability within a very low end-to-end latency. On the other hand, new services place high demands on the flexibility and scalability of the communication system. Industry-standard organizations have embarked on research and proposed several potential solutions. The time-sensitive networking (TSN) task group has developed a series of ethernet-based standards to address issues such as time synchronization and traffic scheduling in industrial networks. Additionally, ultra-reliable and low-latency communications (URLLC) are supported by the 5th generation (5G) mobile communications technology. The combination of 5G and TSN technologies as a solution for industrial communication networks has received much attention, and many related studies have been conducted. In this paper, we investigate how to achieve low-latency communication in a 5G-TSN integrated network by considering non-real-time communication services with high throughput requirements. Simulation results demonstrate that the proposed approach performs well in terms of reducing end-to-end latency and improving system throughput.
In this paper, a turbo-coded FSO system with Mary pulse position modulation is considered over log-normal turbulence channels and an adaptivecoding and modulation scheme is proposed under peak power constraints. In t...
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ISBN:
(纸本)9781728137155
In this paper, a turbo-coded FSO system with Mary pulse position modulation is considered over log-normal turbulence channels and an adaptivecoding and modulation scheme is proposed under peak power constraints. In the proposed system, a link adaptation technique is designed to maximize the bandwidth efficiency of the turbo-coded FSO system by adaptively varying the code rate of turbo code and modulation size according to the channel state information. The simulation results demonstrate significant performance improvements of the proposed adaptivecoding and modulation scheme over coded/uncoded adaptivemodulation and non-adaptive counterparts.
Smart grid is the future development direction of power system, but it is difficult for the traditional data radio station to meet the new business needs. In this study, a wireless communication system combining the l...
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ISBN:
(纸本)9781509059300;9781509059294
Smart grid is the future development direction of power system, but it is difficult for the traditional data radio station to meet the new business needs. In this study, a wireless communication system combining the latest multicarrier communication technology is designed to improve the transmission rate and system reliability to realize information and interaction of smart grid. The system first respectively optimizes the signals in OFDM and GFDM by windowing and filter banks according to the characteristics of 230 MHz channel, so as to realize the suppression of adjacent channel interference at the transmitter. On the other hand, in order to better adapt to the change of the channel conditions, we introduce the adaptive modulation and coding scheme（AMC）. Turbo code is used and the transmission efficiency of different modulation and coding schemes is obtained by simulation. Using the Okamura-Hata model for the 230 MHz band, we obtain the coverage of the cell and the corresponding system performance with different coding rates and scenarios.
Robust service can be achieved in error prone Long Term Evolution-Advanced (LTE-A) by dealing with imperfect Channel Quality Information (CQI). CQI is very crucial in evolved Node B (eNodeB) to decide the correspondin...
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ISBN:
(纸本)9781509024278
Robust service can be achieved in error prone Long Term Evolution-Advanced (LTE-A) by dealing with imperfect Channel Quality Information (CQI). CQI is very crucial in evolved Node B (eNodeB) to decide the corresponding modulation and coding scheme in LTE and LTE-A. User Equipment (UE) will measure and estimate the CQI in order to maximize the throughput performance. adaptive modulation and coding (AMC) is used in order to adapt with the channel variation environments but the wireless channel itself is subject to various impairments including imperfect CQI report which may lead to degradation of the Quality of Service (QoS). The performance of two CQI reporting algorithms which are Automated CQI Reporting Algorithm and Average CQI Reporting Algorithm are being analyzed in this paper. The simulation results demonstrated that the Average CQI Reporting Algorithm produced more promising results with the increment about 15% of the system capacity and capable to support delay up to 63.6% compared to Automated CQI Reporting Algorithm with respect to the Packet Loss Ratio (PLR).
adaptive modulation and coding (AMC) technology plays a critical role in maintaining the transmission quality in 4G LTE (Long Term Evolution) and 5G NR (New Radio) wireless communication systems, to overcome the dynam...
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ISBN:
(纸本)9798350304060;9798350304053
adaptive modulation and coding (AMC) technology plays a critical role in maintaining the transmission quality in 4G LTE (Long Term Evolution) and 5G NR (New Radio) wireless communication systems, to overcome the dynamic fluctuations of radio channel. The performance of AMC may deteriorate significantly if the outdated radio channel information is used for selecting the most suitable modulation and coding scheme. In this paper, an intelligent AMC method based on resource block (RB) group level uplink interference prediction is proposed. By taking the correlation relationships of the RBs into consideration, the AI/ML prediction model are derived in RB group level. It assures good prediction accuracy and also helps to shorten the inference latency. The prediction accuracy and network performance of the proposed solution are verified under a variety of scenarios with varied traffic patterns, network loads and mobility settings of interference users, demonstrating its superiority over existing solutions and applicable scenarios.
a new scheduling and link adaptation scheme is designed for a heterogeneous wireless network where a) different links are using the shared media with various throughput requirement based on their applications, b) link...
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ISBN:
(纸本)9781479989669
a new scheduling and link adaptation scheme is designed for a heterogeneous wireless network where a) different links are using the shared media with various throughput requirement based on their applications, b) links have different characteristics, c) various bit error rate constraints are to be considered at the receivers, d) based on the available power supplies different average transmission power constraints are to be met. A fuzzy based scheme with a low complexity is presented which may be implemented in a wide range of networks where channel's specifications are not available and network structure may be unknown. It is shown that the proposed fuzzy based scheme gives a close performance to analytical approach, however, with substantially lower CSI load and computational cost.
One technique employed by modem cellular systems to increase throughput and reduce errors is the use of hybrid automatic repeat request (H-ARQ) schemes to retransmit packets that are in error. adaptivemodulation and ...
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ISBN:
(纸本)1402044356
One technique employed by modem cellular systems to increase throughput and reduce errors is the use of hybrid automatic repeat request (H-ARQ) schemes to retransmit packets that are in error. adaptive modulation and coding can also be used between transmissions to adjust to the channel conditions for each transmission. However, multiple transmissions and modulation formats lead to a large number of possible combinations for which we need to determine the performance. Effective SINR mapping is a method to map the various combinations into a smaller group of reference states (e.g. a constant modulation and AWGN channel for all transmissions). Previous work has focused on the single-carrier, constant-modulation case in flat fading. In this work, we examine how to perform SINR mapping in a multi-carrier CDMA system with adaptivemodulation and frequency-selective fading.
This paper deals with the design and evaluation of a complementary issue that supports efficient radio resource management strategies in DVB-S2 systems with adaptivecoding and modulation: the selection of suitable mo...
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ISBN:
(纸本)078039206X
This paper deals with the design and evaluation of a complementary issue that supports efficient radio resource management strategies in DVB-S2 systems with adaptivecoding and modulation: the selection of suitable modulation and coding schemes that maximize instantaneous channel efficiency for each receiver. The inherent delays in the considered satellite system causes that when the channel information is available at the Gateway, it is outdated. For this reason, delay compensation techniques are proposed in this paper in order to optimize the selection of suitable physical layer configurations.
Long Term Evolution (LTE) technology aims at addressing the increasing demand for mobile multimedia services in high user density areas. Channel aware scheduling across wide system bandwidth is one of the key techniqu...
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ISBN:
(纸本)9781467318792
Long Term Evolution (LTE) technology aims at addressing the increasing demand for mobile multimedia services in high user density areas. Channel aware scheduling across wide system bandwidth is one of the key techniques enabling this goal. To this end, the LTE scheduler heavily relies on an accurate and robust Link Adaptation (LA) function for predicting the best modulation and coding scheme (MCS) of a user. In this paper, we complement the popular block error rate (BLER) based LA with a scheme maximizing the throughput without BLER constraint and show that it indeed optimizes the spectral efficiency performance. We also describe a sub-optimal UL scheduler providing a good performance/complexity trade-off between a low-complexity basic scheduler and the optimal, but impractical complexity-wise.
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