Average Channel State Information Research Articles

CEMA-LSTM: Enhancing Contextual Feature Correlation for Radar Extrapolation Using Fine-Grained Echo Datasets

Accurate precipitation nowcasting can provide great convenience to the public so they can conduct corresponding arrangements in advance to deal with the possible impact of upcoming heavy rain. Recent relevant research activities have shown their concerns on various deep learning models for radar echo extrapolation, where radar echo maps were used to predict their consequent moment, so as to recognize potential severe convective weather events. However, these approaches suffer from an inaccurate prediction of echo dynamics and unreliable depiction of echo aggregation or dissipation, due to the size limitation of convolution filter, lack of global feature, and less attention to features from previous states. To address the problems, this paper proposes a CEMA-LSTM recurrent unit, which is embedded with a Contextual Feature Correlation Enhancement Block (CEB) and a Multi-Attention Mechanism Block (MAB). The CEB enhances contextual feature correlation and supports its model to memorize significant features for near-future prediction; the MAB uses a position and channel attention mechanism to capture global features of radar echoes. Two practical radar echo datasets were used involving the FREM and CIKM 2017 datasets. Both quantification and visualization of comparative experimental results have demonstrated outperformance of the proposed CEMA-LSTM over recent models, e.g., PhyDNet, MIM and PredRNN++, etc. In particular, compared with the second-ranked model, its average POD, FAR and CSI have been improved by 3.87%, 1.65% and 1.79%, respectively on the FREM, and by 1.42%, 5.60% and 3.16%, respectively on the CIKM 2017.

Batteryless Machine-Type Communications With Average Channel State Information Energy Beamforming

Machine-type communication (MTC) is a key component in 5G and beyond wireless networks, enabling important applications oriented to the industry. In such environments, the limited lifetime of battery-powered solutions becomes a relevant reliability issue. In this paper, we consider a sensor node powered wirelessly by a dedicated multi-antenna power beacon (PB). The harvested energy is directly used by the sensor to power its transceiver and send information to a destination node without storing it in a battery, which would demand non-negligible charging time and potentially compromise the MTC operation. Also, we leverage a packet replication mechanism during information transmission from the sensor to the destination in order to improve the system reliability. We derive the incident power statistics and the outage probability assuming Rician fading channels and only average channel state information at the PB. Then, we define an optimization problem aiming to minimize the energy required by the PB by properly tuning the number of replicated packets and the harvesting time. Results show the existence of an optimal harvesting time as well as an optimal number of replications for a given number of PB antennas, enabling batteryless MTC applications.

Average Rate Approximation and Maximization for RIS-Assisted Multi-User MISO System

In this letter, we investigate a reconfigurable intelligent surface (RIS) assisted downlink multi-user multiple-input single-output (MISO) system. We derive the approximations of average rate of user equipments (UEs) under proper assumptions, and reveal the relations between average rates and system parameters. Furthermore, a RIS configuration algorithm is proposed to improve the average sum rate with low complexity by exploiting the approximation of average rate and statistical channel state information (CSI). The rationality of the assumptions, the tightness of the approximations and the effectiveness of the proposed algorithm are validated by numerical results.

Massive Wireless Energy Transfer: Enabling Sustainable IoT Toward 6G Era

Recent advances on wireless energy transfer (WET) make it a promising solution for powering future Internet-of-Things (IoT) devices enabled by the upcoming sixth-generation (6G) era. The main architectures, challenges and techniques for efficient and scalable wireless powering are overviewed in this article. Candidates enablers, such as energy beamforming (EB), distributed antenna systems (DASs), advances on devices' hardware and programmable medium, new spectrum opportunities, resource scheduling, and distributed ledger technology are outlined. Special emphasis is placed on discussing the suitability of channel state information (CSI)-limited/free strategies when powering simultaneously a massive number of devices. The benefits from combining DAS and EB, and from using average CSI whenever available, are numerically illustrated. The pros and cons of the state-of-the-art CSI-free WET techniques in ultralow power setups are thoroughly revised, and some possible future enhancements are outlined. Finally, key research directions toward realizing WET-enabled massive IoT networks in the 6G era are identified and discussed in detail.

ANALISIS PENYELENGGARAAN PELAYANAN PUBLIK: SURVEI INDEKS KEPUASAN MASYARAKAT DI PEMDA KABUPATEN JAYAPURA TAHUN 2019

Quality public service with a high level of community satisfaction are the determinants of the success of local governments in realizing good governance and sustainable development. This paper aims to present empirical data related to public service practices in Jayapura Regency. The purpose of this study is to precisely measure service quality; determine the satisfaction index; and perform a theoretical-conceptual study on the implementation of public service delivery in Jayapura Regency as mandated by Regulation of the Minister of State Apparatus Empowerment and Bureaucratic Reform of the Republic of Indonesia No.14 of 2017 on Guidelines of Public Satisfaction Surveys for Public Service. The research method used is descriptive quantitative. Primary data were collected from community satisfaction survey to obtain the Jayapura Regency Community Satisfaction Index (IKM). Based on results of data processing, CSI for Yowari Hospital of Jayapura District is 2,69, while CSI for DPMPTSP of Jayapura District is 2,91, and Dispendukcapil obtained an average CSI value of 2,83. The CSI value of those three RGOs are all categorized as “C”, defined as “Not Good Enough”, which indicates that the need for public service management improvement is crucial, both in terms of infrastructure and employee’s competency in deliviring excellent services.

On the Achievable Rate of MISO Fading Channels With Instantaneous CSI Only at the Transmitter

We investigate Multiple-Input Single-Output (MISO) fading channels with perfect instantaneous Channel State Information (CSI) at the transmitter and with statistical average CSI at the receiver. We outline achievable rates for maximum ratio transmission and show that the rate loss of not having instantaneous CSI at the receiver behaves like an additional noise term whose variance is equal to one fourth of the transmit power. Similar results are obtained for equal gain transmission. The simulation results are in agreement with the theoretical bounds and indicate that requirement of instantaneous CSI at the receiver becomes obsolete up to a certain transmit power.

Throughput Analysis of Low-Latency IoT Systems With QoS Constraints and Finite Blocklength Codes

Internet of Things (IoT) is a promising paradigm to connect massive number of devices in future wireless communications while satisfying various quality of service (QoS) requirements. In this paper, we consider a QoS-constrained IoT system operating with finite blocklength (FBL) codes to support low latency communications. Two data arrival models are considered, namely, constant-rate arrival and ON-OFF discrete-time Markov arrival. The throughput performance is studied for both arrival models under statistical queuing constraints and deadline limits. For the scenario with instantaneous channel state information (CSI), we derive the QoS-constrained throughput expressions for both arrival models. Subsequently, an instantaneous-CSI-driven optimal power control algorithm is proposed to maximize the throughput, while guaranteeing a certain reliability target. In addition, we consider a scenario with only average CSI being available at the transmitter and propose to apply hybrid automatic repeat request (HARQ) schemes to improve the FBL performance. The decoding error probability and the outage probability are first characterized, following which the distribution of transmission period is derived. Furthermore, the throughput expressions are provided for both types of arrivals. Via numerical analysis, the impact of error probability, fixed transmission rate, coding blocklength, and QoS constraints on the throughput is studied.

Assessing the Food Security of Vulnerable Agricultural Households to Climate Change in the Council of Tokombéré, Far North Région of Cameroon: An Analysis Focused on the FCS, HDDS and CSI

This article evaluates the food security of agricultural producers vulnerable to climate change in the Tokombere council through the analysis of food consumption scores, dietary diversity score and the analysis of the index of adaptability for the food. The data were collected using a questionnaire administered to 160 farm households that were selected by the stratified random sampling technique. Analysis of the data collected reveals that 82.5% of households are headed by men and 17.5% by women with very low level of education (55% have not been to school and only 45% have a primary level) and have an age between 50 and 75 (70.6%). The average SCA is 37.06 (acceptable), so 36.88% of households have an acceptable SCA of which in food security and 56.88% have a SCA limit of which moderately food insecure and 6.25% have a SCA poor whose food insecurity is severe. The average SDAM is 3.58 (acceptable) with a minimum SDAM of 2 and a maximum SDAM of 9. With SDAM; 90% and 79.12% of households are severely food insecure and moderately food insecure respectively. SDAM analyzes also show 75.6%, 20% and 4.4% of households with the lowest, average and highest dietary diversity respectively. The average CSI is 21.1 with a CSI min of 11 and a CSI max of 30.

On the Performance of NOMA With Hybrid ARQ

In this paper, we investigate the outage performance of hybrid automatic repeat request with chase combining (HARQ-CC) assisted downlink non-orthogonal multiple access (NOMA) systems. A closed-form expression of the individual outage probability and the diversity gain are obtained firstly. Based on the developed analytical outage probability, a tradeoff between the minimum number of retransmissions and the transmit power allocation coefficient is then provided for a given target rate. The provided simulation results demonstrate the accuracy of the developed analytical results. Moreover, it is shown that NOMA combined with the HARQ-CC can achieve a significant advantage when only average channel state information is known at the transmitter. Particularly, the performance of the user with less transmit power in NOMA systems can be efficiently improved by utilizing HARQ-CC.

Average CsI Neutron Density Distribution from COHERENT Data.

Using the coherent elastic neutrino-nucleus scattering data of the COHERENT experiment, we determine for the first time the average neutron rms radius of ^{133}Cs and ^{127}I. We obtain the practically model-independent value R_{n}=5.5_{-1.1}^{+0.9} fm using the symmetrized Fermi and Helm form factors. We also point out that the COHERENT data show a 2.3σ evidence of the nuclear structure suppression of the full coherence.

User Perceived Qos Provisioning for Video Streaming in Wireless OFDMA Systems: Admission Control and Resource Allocation

In this paper, we investigate a joint admission control (AC) and resource allocation (RA) scheme for providing quality of service (QoS) guarantees for video streaming in OFDMA networks. The QoS provisioning is posed as a network utility maximization (NUM) problem. We prove that the QoS requirements are mainly dominated by the average data rate with the aid of diffusion approximation approach, allowing us to decompose the NUM problem into two tractable sub-problems, namely, the AC and the RA sub-problems. We develop an AC algorithm, which enables us to select a maximum user set such that all selected users can meet their QoS requirements related to user perceived video quality during the video playback period. In addition, in order to handle the computational complexity, we further split the RA sub-problem into the constrained Markov decision process associated problems performed at users together with a transmission problem performed at the base station. Correspondingly, we develop a power and sub-carrier allocation algorithm to minimize the average power consumption. The decision of AC is made in a long timescale and depends on the average channel state information (CSI), whereas the decision of RA is made in a short timescale and is subject to both instantaneous CSI and queue state information. Simulation results demonstrate the advantages of the proposed algorithms.

Underlay Spectrum Sharing Techniques With In-Band Full-Duplex Systems Using Improper Gaussian Signaling

Sharing the spectrum with in-band full-duplex (FD) primary users (PUs) is a challenging and interesting problem in the underlay cognitive radio systems. The self-interference introduced at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. To tackle this problem, we use the so-called improper Gaussian signaling . Particularly, we assume the downlink transmission of a SU that uses improper Gaussian signaling while the FD PU pair implements the regular proper Gaussian signaling. First, we derive a closed-form expression and an upper bound for the SU and PUs outage probabilities, respectively. Second, we optimize the SU signal parameters to minimize its outage probability while maintaining the required PUs quality-of-service based on the average channel state information (CSI). Moreover, we provide the conditions to reap merits from employing improper Gaussian signaling at the SU. Third, we design the SU signal parameters based on the perfect knowledge of its direct link instantaneous CSI and investigate all benefits that can be achieved at both the SU and PUs. Finally, we provide some numerical results that demonstrate the advantages of using improper Gaussian signaling to access the spectrum of the FD PUs.

Hybrid Beamforming for Massive MIMO: A Survey

Hybrid multiple-antenna transceivers, which combine large-dimensional analog pre/postprocessing with lower-dimensional digital processing, are the most promising approach for reducing the hardware cost and training overhead in massive MIMO systems. This paper provides a comprehensive survey of the various incarnations of such structures that have been proposed in the literature. We provide a taxonomy in terms of the required channel state information (CSI), namely whether the processing adapts to the instantaneous or the average (second-order) CSI; while the former provides somewhat better signal-to-noise and interference ratio (SNIR), the latter has much lower overhead for CSI acquisition. We furthermore distinguish hardware structures of different complexities. Finally, we point out the special design aspects for operation at millimeter-wave frequencies.

Diversity Backpressure Scheduling and Routing With Mutual Information Accumulation in Wireless Ad-Hoc Networks

We suggest and analyze algorithms for routing in multi-hop wireless ad-hoc networks that exploit mutual information accumulation as the physical layer transmission scheme, and are capable of routing multiple packet streams (commodities) when only the average channel state information is present and that only locally. The proposed algorithms are modifications of the Diversity Backpressure (DIVBAR) algorithm, under which the packet whose commodity has the largest "backpressure metric" is chosen to be transmitted and is forwarded through the link with the largest differential backlog (queue length). In contrast to traditional DIVBAR, each receiving node stores and accumulates the partially received packet in a separate "partial packet queue", thus increasing the probability of successful reception during a later possible retransmission. We present two variants of the algorithm: DIVBAR-RMIA, under which all the receiving nodes clear the received partial information of a packet once one or more receiving nodes firstly decode the packet; and DIVBAR-MIA, under which all the receiving nodes retain the partial information of a packet until the packet has reached its destination. We characterize the network capacity region with RMIA and prove that (under certain mild conditions) it is strictly larger than the network capacity region with the repetition (REP) transmission scheme that is used by the traditional DIVBAR. We also prove that DIVBAR-RMIA is throughput-optimum among the polices with RMIA, i.e., it achieves the network capacity region with RMIA, which in turn demonstrates that DIVBAR-RMIA outperforms traditional DIVBAR on the achievable throughput. Moreover, we prove that DIVBAR-MIA performs at least as well as DIVBAR-RMIA with respect to throughput. Simulations also confirm these results.

A Novel Power Allocation Scheme Under Outage Constraints in NOMA Systems

In this letter, we study a downlink non-orthogonal multiple access (NOMA) transmission system, where only the average channel state information (CSI) is available at the transmitter. Two criteria in terms of transmit power and user fairness for NOMA systems are used to formulate two optimization problems, subjected to outage probabilistic constraints and the optimal decoding order. We first investigate the optimal decoding order when the transmitter knows only the average CSI, and then, we develop the optimal power allocation schemes in closed form by employing the feature of the NOMA principle for the two problems. Furthermore, the power difference between NOMA systems and OMA systems under outage constraints is obtained.

Performance of switching‐based partial relay selection scheme for amplify‐and‐forward cognitive relay networks

The outage probabilities (OPs) of cognitive amplify-and-forward systems with the conventional and the switching-based partial relay selection (PRS) schemes over independent but not identically distributed Rayleigh fading channels are evaluated. The conventional PRS scheme always depends on the instantaneous channel quality of the first hop, while the switching-based PRS scheme is based on the estimated average channel state information (CSI) of the first and second hops. For the switching-based PRS scheme, the instantaneous CSI for links with the smaller average channel power in the first and the second hops for each end-to-end path is used for relay selection. Thus, the switching-based PRS scheme counts on the instantaneous CSI of either the first or second hop. The tight lower bounds and asymptotic expressions of the OP are derived. The feedback overheads of both schemes are discussed. Simulation results substantiate the theoretical analysis and also reveal that the switching-based PRS outperforms the conventional one over the cognitive relay networks in terms of OP.

Blocklength-Limited Performance of Relaying under Quasi-Static Rayleigh Channels

In this paper, the blocklength-limited performance of a relaying system is studied, where channels are assumed to experience quasi-static Rayleigh fading while at the same time only the average channel state information (CSI) is available at the source. Both the physical-layer performance (blocklength-limited throughput) and the link-layer performance (effective capacity) of the relaying system are investigated. We propose a simple system operation by introducing a factor based on which we weight the average CSI and let the source determine the coding rate accordingly. In particular, we prove that both the blocklength-limited throughput and the effective capacity are quasi-concave in the weight factor. Through numerical investigations, we show the appropriateness of our theoretical model. In addition, we observe that relaying is more efficient than direct transmission. Moreover, this performance advantage of relaying under the average CSI scenario is more significant than under the perfect CSI scenario. Finally, the speed of convergence (between the blocklength-limited performance and the performance in the Shannon capacity regime) in relaying system is faster in comparison to the direct transmission under both the average CSI scenario and the perfect CSI scenario.

Fairness for Non-Orthogonal Multiple Access in 5G Systems

In non-orthogonal multiple access (NOMA) downlink, multiple data flows are superimposed in the power domain and user decoding is based on successive interference cancellation. NOMA's performance highly depends on the power split among the data flows and the associated power allocation (PA) problem. In this letter, we study NOMA from a fairness standpoint and we investigate PA techniques that ensure fairness for the downlink users under i) instantaneous channel state information (CSI) at the transmitter, and ii) average CSI. Although the formulated problems are non-convex, we have developed low-complexity polynomial algorithms that yield the optimal solution in both cases considered.

QoS-Constrained Energy Efficiency of Cooperative ARQ in Multiple DF Relay Systems

In this paper, we study the higher layer performance as well as the “throughput, delay, energy consumption” tradeoff problem for multirelay-assisted cooperative automatic repeat request (C-ARQ) protocols. We study a practical scenario where only the average channel state information (CSI) is available at the source and relays. We consider four multirelay C-ARQ protocols and derive closed-form expressions for the transmission delay distribution, the energy consumption, and the higher layer queuing performance. Furthermore, we analyze the quality of service (QoS)-constrained energy efficiency performances of the protocols. Our analysis is validated by simulations. In addition, we evaluate the system performance under these C-ARQ protocols and for different topologies. We conclude several guidelines for the design of efficient C-ARQ protocols. Finally, a simple extension of the studied C-ARQ protocols is proposed, which improves the QoS-constrained energy efficiency by 4%.

Cooperative Resource Allocation in Multicast Networks for Outage Probability Minimization

In this paper, we investigate the resource allocation issues in Orthogonal frequency division multiplexing access-based multicast systems that only allows average channel state information of users to be available at the resource manager. In this system, it is impossible to guarantee successful transmission of every data due to instant deep fading. Hence, in order to achieve efficient and reliable transmission, we exploit potential advantage provided by the cooperative diversity and propose a cooperative joint subcarrier and power allocation scheme that minimizes the probability of multicast transmission failure. This combinable allocation issue has high computational complexity, so we allocate subcarrier and power separately. We proposed cooperative proportional subcarrier allocation strategy to achieve tradeoff between throughput and fairness and iterative power (IP) allocation strategy to fully utilize the limited power. Simulation results show that system performance of the schemes with cooperation is significantly enhanced compared with that without cooperation and the schemes with IP remarkably outperform that without.