scholarly journals Implementation and Evaluation of WLAN 802.11ac for Residential Networks in NS-3

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Andy Bubune Amewuda ◽  
Ferdinand Apietu Katsriku ◽  
Jamal-Deen Abdulai

Wi-Fi has been an amazingly successful technology. Its success may be attributed to the fact that, despite the significant advances made in technology over the last decade, it has remained backward compatible. 802.11ac is the latest version of the wireless LAN (WLAN) standard that is currently being adopted, and it promises to deliver very high throughput (VHT), operating at the 5 GHz band. In this paper, we report on an implementation of 802.11ac wireless LAN for residential scenario based on the 802.11ax task group scenario document. We evaluate the 802.11ac protocol performance under different operating conditions. Key features such as modulation coding set (MCS), frame aggregation, and multiple-input multiple-output (MIMO) were investigated. We also evaluate the average throughput, delay, jitter, optimum range for goodput, and effect of station (STA) density per access point (AP) in a network. ns-3, an open source network simulator with features supporting 802.11ac, was used to perform the simulation. Results obtained indicate that very high data rates are achievable. The highest data rate, the best mean delay, and mean jitter are possible under combined features of 802.11ac (MIMO and A-MPDU).

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1325
Author(s):  
Yunwei Zhang ◽  
Weigang Wang ◽  
Chendong Xu ◽  
Jie Qin ◽  
Shujuan Yu ◽  
...  

With the rise of location-based services and the rapidly growing requirements related to their applications, indoor localization based on channel state information–multiple-input multiple-output (CSI-MIMO) has become an important research topic. However, indoor localization based on CSI-MIMO has some disadvantages, including noise and high data dimensions. To overcome the above drawbacks, we proposed a novel method of indoor localization based on CSI-MIMO, named SICD. For SICD, a novel localization fingerprint was first designed which can reflect the time–frequency and space–frequency characteristics of CSI-MIMO under a single access point (AP). To reduce the redundancy in the data of CSI-MIMO amplitude, we developed a data dimensionality reduction algorithm. Moreover, by leveraging a log-normal distribution, we calculated the conditional probability of the naive Bayes classifier, which was used to predict the moving object’s location. Compared with other state-of-the-art methods, the results of the experiment confirm that the SICD effectively improves localization accuracy.


Author(s):  
Indrasto Jati P ◽  
S.El Yumin

TV over IP merupakan salah satu aplikasi komunikasi multimedia yang memanfaatkan prosesstreaming dalam pengiriman paket-paket data videonya melalui jaringan Internet Protokol (IP). Karenaditerapkan pada jaringan yang berbasis IP, maka akan menggunakan transmisi secara real time yang dapatdibroadcast melalui wireless LAN. Smartphone android akan memberikan manfaat yang lebih karena sudahdilengkapi dengan perangkat wireless. Dalam makalah ini dibahas perancangan server TV over IP denganmenggunakan USB TV tuner untuk menangkap siaran televisi. Untuk membroadcast siaran televisi digunakanperangkat access point melalui jaringan wireless LAN. Pengguna smartphone android yang mempunyaiperangkat wirelss dapat mengakses siaran televisi yang dibroadcast oleh server. Dari implementasi yang telahdilakukan akan dianalisa kualitas layanan streaming atau Quality of Services (QoS) berupa throughput, delay,jitter, dan packet loss. Analisis perencanaan penambahan user dengan simulasi penambahan background trafficdan perencanaan jarak yang semakin jauh dari server akan menurunkan kualitas layanan. Nilai througput akanberbanding terbalik dengan packet loss, tetapi pada pengujian yang dilakukan nilai jitter tidak stabil karenaberpengaruh dari interval delay yang tidak teratur pada paket yang diterima. Jadi dapat disimpulkan bahwasemakin banyak user yang mengakses streaming server maka nilai kualitas layanan akan semakin menurunkarena bandwidth akan semakin kecil yang disebabkan oleh padatnya traffic pada wireless LAN. Denganperancangan TV over IP ini dapat mempermudah bagi pengguna perangkat yang mempunyai wireless sepertismartphone android untuk meengakses siaran televisi lokal di dalam area jangkauan wireless. Dengan layananTV yang berbasis IP akan menghasilkan gambar yang lebih interaktif. Karena merupakan layanan streamingmaka TV over IP rentan dengan kebutuhan bandwidth dengan jumlah kenaikan user dan juga padaperancangan wireless terbatas pada jarak tertentu.


Author(s):  
Neetika Jain ◽  
Sangeeta Mittal

Background: Real Time Wireless Sensor Networks (RT-WSN) have hard real time packet delivery requirements. Due to resource constraints of sensors, these networks need to trade-off energy and latency. Objective: In this paper, a routing protocol for RT-WSN named “SPREAD” has been proposed. The underlying idea is to reserve laxity by assuming tighter packet deadline than actual. This reserved laxity is used when no deadline-meeting next hop is available. Objective: As a result, if due to repeated transmissions, energy of nodes on shortest path is drained out, then time is still left to route the packet dynamically through other path without missing the deadline. Results: Congestion scenarios have been addressed by dynamically assessing 1-hop delays and avoiding traffic on congested paths. Conclusion: Through extensive simulations in Network Simulator NS2, it has been observed that SPREAD algorithm not only significantly reduces miss ratio as compared to other similar protocols but also keeps energy consumption under control. It also shows more resilience towards high data rate and tight deadlines than existing popular protocols.


Author(s):  
John D. Terry ◽  
Juha Heiskala ◽  
Victor Stolpman ◽  
Majid Fozunbal

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Cong-Nam Tran ◽  
Nam-Hoang Nguyen ◽  
Trong-Minh Hoang

AbstractVisible light communications (VLC) is considered as an alternative communications technology for providing indoor wireless services. VLC systems are expected to offer high data transmission rate and seamless coverage. In order to achieve these requirements, VLC systems utilizing multi-lightbeam access points (multibeam VLC-AP) for downlink transmission have been proposed recently. In this paper, we present a lightbeam configuration method and an interference elimination resource scheduling mechanism (IERS) for indoor multibeam multi-access point VLC systems. The proposed lightbeam configuration method ensures seamless connectivity between user equipment and VLC-AP. The proposed IERS mechanism consists of a beam assignment algorithm and a resource allocation algorithm for eliminating co-channel interference as well as improving system performance. Performance results obtained by computer simulation indicate that there are significant improvements in terms of downlink signal to interference plus noise ratio, user throughput and packet delay when the proposed IERS mechanism is deployed.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saad M. Hardan ◽  
Ayad A. Abdulkafi ◽  
Saadi Hamad Thalij ◽  
Sherine S. Jumaah

Abstract The continued increase in several mobile applications forces to replace existing limited spectrum indoor radio frequency wireless connections with high-speed ones. Visible light communications (VLC) technology has gained prominence in the development of high data rate transmission for fifth-generation networks. In optical wireless communications, light-emitting diode (LED) transmitters are used in applications that desire mobility as LED divergence enables larger coverage. Since each VLC access point covers a small area, handovers of mobile users are inevitable. Wavelength division multiplexing (WDM) can be used in VLC systems to tackle the above issue and to meet the increasing demand for indoor connectivity with high bit rates. In this paper, a new system architecture for WDM with coded modulated optical in orthogonal frequency division multiplexing (OFDM) VLC system in conjunction with red, green, blue, and yellow (RGBY) LEDs is proposed to reduce the impact of random receiver orientation of indoor mobile users over VLC downlink channels and improves the system’s bit-error-rate (BER) performance. Simulation results show that the proposed method is not affected by the user’s mobility and hence it performs better than other approaches, in terms of BER for all scenarios and at all positions. This study reveals that using WDM-OFDM-VLC with RGBY LEDs to construct a VLC system is very promising.


2016 ◽  
Vol 3 (1) ◽  
pp. 31-39
Author(s):  
F Ammar ◽  
Hanafi Hanafi

WiFi bekerja pada band 2,4 GHz dan 5 GHz. Standar WiFi yang bekerja pada frekuensi ini antara lain IEEE802.11g dan IEEE802.11a. Pada penelitian ini dilakukan pengukuran terhadap transfer rate download dan upload data dengan standar IEEE802.11g dan IEEE802.11a. Pengukuran dilakukan pada kanal Line of Sight (LOS), menggunakan dua buah laptop yang dihubungkan dengan Access Point (AP) standar IEEE802.11g dan IEEE802.11a.  Hasil penelitian diperoleh, pada standar IEEE802.11g, transfer rate download dan upload data tertinggi 2.662,54.KB/s dan 2.549,60 KB/s, dan terendah 484,50.KB/s dan 477,40 KB/s, sedangkan pada standar IEEE802.11a, transfer rate download dan upload data tertinggi 8.104,68 KB/s dan 5.744,24 KB/s, dan terendah 872,24 KB/s dan 465,38.KB/s. Pada standar IEEE802.11g, transfer rate download dan upload data pada sinyal terendah hingga di bawah 35% dan 30%, dari transfer rate download dan upload data tertinggi. Pada standar IEEE802.11a, transfer rate download dan upload data pada kualitas sinyal terendah hingga di bawah 20% dan 30%, dari transfer rate download dan upload data tertinggi. Kemampuan transfer rate download data Standar IEEE802.11a, 2–3 kali lebih baik pada kondisi kualitas sinyal tertinggi, dan tidak lebih dari 2 kali pada kondisi kualitas sinyal terendah, dibandingkan kemampuan transfer rate download data standar IEEE802.11g. Kemampuan transfer rate upload data Standar IEEE802.11a, 1,4–3 kali lebih baik pada kondisi kualitas sinyal tertinggi, dan 1-3 kali lebih baik pada kondisi kualitas sinyal terendah, dibandingkan kemampuan transfer rate upload data standar IEEE802.11g.


2022 ◽  
Author(s):  
Chen Wei ◽  
Kui Xu ◽  
Zhexian Shen ◽  
Xiaochen Xia ◽  
Wei Xie ◽  
...  

Abstract In this paper, we investigate the uplink transmission for user-centric cell-free massive multiple-input multiple-output (MIMO) systems. The largest-large-scale-fading-based access point (AP) selection method is adopted to achieve a user-centric operation. Under this user-centric framework, we propose a novel inter-cluster interference-based (IC-IB) pilot assignment scheme to alleviate pilot contamination. Considering the local characteristics of channel estimates and statistics, we propose a location-aided distributed uplink combining scheme based on a novel proposed metric representing inter-user interference to balance the relationship among the spectral efficiency (SE), user equipment (UE) fairness and complexity, in which the normalized local partial minimum mean-squared error (LP-MMSE) combining is adopted for some APs, while the normalized maximum ratio (MR) combining is adopted for the remaining APs. A new closed-form SE expression using the normalized MR combining is derived and a novel metric to indicate the UE fairness is also proposed. Moreover, the max-min fairness (MMF) power control algorithm is utilized to further ensure uniformly good service to the UEs. Simulation results demonstrate that the channel estimation accuracy of our proposed IC-IB pilot assignment scheme outperforms that of the conventional pilot assignment schemes. Furthermore, although the proposed location-aided uplink combining scheme is not always the best in terms of the per-UE SE, it can provide the more fairness among UEs and can achieve a good trade-off between the average SE and computational complexity.


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