scholarly journals Low Latency Driven Effective Capacity Analysis for Non-Orthogonal and Orthogonal Spectrum Access

Author(s):  
Wenjuan Yu ◽  
Leila Musavian ◽  
Atta Ul Quddus ◽  
Qiang Ni ◽  
Pei Xiao
2021 ◽  
Vol 11 (23) ◽  
pp. 11438
Author(s):  
Xiurong Zhang ◽  
Xinwei Yue ◽  
Shaoli Kang

Low latency and a massive connection have become the requirements of energy internet wireless communication. Effective capacity analysis of non-orthogonal multiple access (NOMA) networks with short packets is of vital importance in energy internet communication planning and design. Low-latency communications are one of the main application scenarios in next-generation wireless networks. This paper focuses on the effective capacity of NOMA networks, where the finite blocklength, delay exponent, and transmission error probability are taken into account. New exact and asymptotic expressions of effective capacities are derived for arbitrarily ordered users with a finite blocklength. Based on the analytical results, the high Signal-to-Noise Ratio slopes of effective capacity in NOMA networks are carefully attained. The numerical results validate that (a) non-orthogonal users are capable of obtaining a larger effective capacity when the blocklength decreases, and that (b), as the value of the error probability and delay exponent increases, the effective capacity of non-orthogonal users worsens.


2019 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Yuono Mugi Kuncoro ◽  
Djoko Trijanto ◽  
Medi Efendi

In dry season Tarokan Sub-district of Kediri, often suffers from drought, so a small dam (embung) was required. The objectives of the study are to determine the dimension of the dam, its spillway and to analyze its stability. The required data were of rainfall, topographic maps, soil, and population.The initial design was hydrologic analysis by finding out the planned discharge Q50 and determining the water volume of inflow. To determine the effective catchment ponds, capacity analysis using topographical data and comparing the volume of water available. And analysis of spillway to determine the flood water level.The analyses result, the amount of the water needs of a population of 258.854.400m3, and the magnitude of the draft Q50 discharge of in 4.027 m3/sec (The  room  for  sediment  is  29,234.9 m3  at  elevation  1 m from the bottom of the pool); 390,000m3 effective capacity at +131.75 elevation, and flood water level at +132.75 elevation. The dimension of embung main dam is 6 m deep; embung crest at +133.00 elevation ; 3m wide embung crest ; 1:3 upstream slope; 1 : 2.25 downstream slope ; 10 m wide spillway channel 1 : 1 slope of wall of spillway channel ; and crest of spillway at +131.75. Geostudio software was used to calculate the figures safety against sliding. Keywords: embung, spillway, embung dimensions, slope stabilty


Author(s):  
Redouane Sassioui ◽  
Leszek Szczecinski ◽  
Long Le ◽  
Mustapha Benjillali

2021 ◽  
Author(s):  
Mohamed Elalem

With the rapid development of wireless services and applications, the currently radio spectrum is becoming more crowded. How to accommodate more wireless services and applications within the limited radio spectrum becomes a big challenge faced by modern society. Cognitive radio (CR) is proposed as a promising technology to tackle this challenge by introducing secondary users (SUs) to opportunistically or concurrently access the spectrum allocated to primary users (PUs). Currently, there are two prevalent CR models: the spectrum sharing model and the opportunistic spectrum access model. In the spectrum sharing model, the SUs are allowed to coexist with the PUs as long as the interferences from SUs do not degrade the quality of service (QoS) of PUs to an unacceptable level. In the opportunistic spectrum access model, SUs are allowed to access the spectrum only if the PUs are detected to be inactive. These two models known as underlay and overlay schemes, respectively. This thesis studies a number of topics in CR networks under the framework of these two schemes. First, studied cognitive radio transmissions under QoS delay constraints. Initially, we focused on the concept: effective capacity for cognitive radio channels in order to identify the performance in the presence of QoS constraints. Both underlay and overlay schemes are studied taking into consideration the activity of primary users, and assuming the general case of channel fading as Gamma distribution. For this setting, we further proposed a selection criterion by which the cognitive radio network can choose the adequate mode of operation. Then, we studied the cognitive radio transmissions focusing on Rayleigh fading channel and assumed that no prior channel knowledge is available at the transmitter and the receiver. We investigated the performance of pilot-assisted transmission strategies. In particular, we analyzed the channel estimation using minimum mean-square-error (MMSE) estimation, and analyzed efficient resource allocation strategies. In both cases, power allocations and effective capacity optimization were obtained. Effective capacity and interference constraint were analyzed in both single-band and multi-band spectrum sensing settings. Finally, we studied optimal access probabilities for cognitive radio network using Markov model to achieve maximum throughput for both CR schemes.


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