scholarly journals Identifying Opportunities for Exploiting Cross-Layer Interactions in Adaptive Wireless Systems

2007 ◽  
Vol 2007 ◽  
pp. 1-11 ◽  
Author(s):  
Troy Weingart ◽  
Douglas C. Sicker ◽  
Dirk Grunwald
Keyword(s):  
Error Detection ◽  
Software Defined Radio ◽  
Forward Error Correction ◽  
Instant Messaging ◽  
Transport Layer ◽  
Cross Layer ◽  
File Transfer ◽  
Data Link ◽  
Frame Size ◽  
Forward Error

The flexibility of cognitive and software-defined radio heralds an opportunity for researchers to reexamine how network protocol layers operate with respect to providing quality of service aware transmission among wireless nodes. This opportunity is enhanced by the continued development of spectrally responsive devices—ones that can detect and respond to changes in the radio frequency environment. Present wireless network protocols define reliability and other performance-related tasks narrowly within layers. For example, the frame size employed on 802.11 can substantially influence the throughput, delay, and jitter experienced by an application, but there is no simple way to adapt this parameter. Furthermore, while the data link layer of 802.11 provides error detection capabilities across a link, it does not specify additional features, such as forward error correction schemes, nor does it provide a means for throttling retransmissions at the transport layer (currently, the data link and transport layer can function counterproductively with respect to reliability). This paper presents an analysis of the interaction of physical, data link, and network layer parameters with respect to throughput, bit error rate, delay, and jitter. The goal of this analysis is to identify opportunities where system designers might exploit cross-layer interactions to improve the performance of Voice over IP (VoIP), instant messaging (IM), and file transfer applications.

A Cross-Layer Model for Video Multicast Based TCP-Adaptive FEC over Heterogeneous Networks

2010 ◽  
pp. 1879-1895
Author(s):  
Ghaida A. AL-Suhail ◽  
Liansheng Tan ◽  
Rodney A. Kennedy
Keyword(s):  
Forward Error Correction ◽  
Video Quality ◽  
Wireless Channel ◽  
Cross Layer ◽  
Radio Link ◽  
Layer Model ◽  
Data Link ◽  
Link Layer ◽  
Adaptive Fec ◽  
Forward Error

In this article, we present a simple cross-layer model that leads to the optimal throughput of multiple users for multicasting MPEG-4 video over a heterogeneous network. For heterogeneous wired-to-wireless network, at the last wireless hop there are bit errors associated with the link-layer packets that are arising in the wireless channel, in addition of overflow packet dropping over wired links. We employ a heuristic TCP function to optimize the cross-layer model of data link and physical (radio-link) layer. An adaptive Forward-Error-Correction (FEC) scheme is applied at the byte-level as well as at the packet-level. The corresponding optimal video quality can be evaluated at each client end. The results show that a server can significantly adapt to the bandwidth and FEC codes to maximize the video quality of service (QoS) in terms of temporal scaling when a maximum network throughput for each client is reached.

scholarly journals FPGA-Implemented Fractal Decoder with Forward Error Correction in Short-Reach Optical Interconnects

Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 122
Author(s):  
Svitlana Matsenko ◽  
Oleksiy Borysenko ◽  
Sandis Spolitis ◽  
Aleksejs Udalcovs ◽  
Lilita Gegere ◽  
...  
Keyword(s):  
Error Correction ◽  
Error Detection ◽  
Optical Interconnects ◽  
Error Control ◽  
Forward Error Correction ◽  
Golden Ratio ◽  
Probability Method ◽  
Additional Error ◽  
Hardware Costs ◽  
Forward Error

Forward error correction (FEC) codes combined with high-order modulator formats, i.e., coded modulation (CM), are essential in optical communication networks to achieve highly efficient and reliable communication. The task of providing additional error control in the design of CM systems with high-performance requirements remains urgent. As an additional control of CM systems, we propose to use indivisible error detection codes based on a positional number system. In this work, we evaluated the indivisible code using the average probability method (APM) for the binary symmetric channel (BSC), which has the simplicity, versatility and reliability of the estimate, which is close to reality. The APM allows for evaluation and compares indivisible codes according to parameters of correct transmission, and detectable and undetectable errors. Indivisible codes allow for the end-to-end (E2E) control of the transmission and processing of information in digital systems and design devices with a regular structure and high speed. This study researched a fractal decoder device for additional error control, implemented in field-programmable gate array (FPGA) software with FEC for short-reach optical interconnects with multilevel pulse amplitude (PAM-M) modulated with Gray code mapping. Indivisible codes with natural redundancy require far fewer hardware costs to develop and implement encoding and decoding devices with a sufficiently high error detection efficiency. We achieved a reduction in hardware costs for a fractal decoder by using the fractal property of the indivisible code from 10% to 30% for different n while receiving the reciprocal of the golden ratio.

ANALISIS KEADILAN MODEL PENJADWALAN YANG DIINTEGRASIKAN DENGAN HARQ PADA SISTEM LTE

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Danu Dwi Sanjoyo ◽  
Rendy Munadi ◽  
Ida Wahidah
Keyword(s):  
Error Correction ◽  
Error Detection ◽  
Forward Error Correction ◽  
Proportional Fairness ◽  
Quality Information ◽  
Channel Quality ◽  
Term Evolution ◽  
Forward Error ◽  
Channel Quality Information

Penjadwalan pada Long Term Evolution (LTE) memiliki peran dalam melayani kebutuhan bandwidth yang besar. Oleh karena itu, jaringan seluler LTE membutuhkan algoritma penjadwalan yang mampu mengakomodasi informasi keluaran dari proses HARQ untuk meningkatkan fairness. Algoritma penjadwalan dikombinasikan dengan proses HARQ untuk meningkatkan keadilan throughput yang diterima oleh pengguna. Redundancy Version (RV) yang diperoleh dari proses HARQ dikombinasikan dengan nilai prioritas layanan dan Channel Quality Information (CQI) menjadi suatu nilai metrik yang digunakan untuk menentukan prioritas paket pada proses penjadwalan. Algoritma penjadwalan diujikan pada makalah ini adalah Round Robin (RR), Maximum C/I (CI), dan Proportional Fairness (PF). Proses HARQ di penerima melakukan Error Detection (ED) dan Forward Error Correction (FEC) pada paket yang diterima. User Equipment (UE) akan mengirimkan feedback ke eNode-B yang berisi informasi apakah paket berhasil diterima dengan benar atau tidak. Integrasi masing-masing algoritma penjadwalan (RR, CI, dan PF) dengan nilai CQI, rangking paket data, dan RV dapat meningkatkan nilai fairness antarpengguna. Jain�s Fairnees Index, sebagai parameter keadilan, menunjukkan adanya peningkatan keadilan throughput.Kata kunci: LTE, penjadwalan, HARQ, Jain�s Fairness Index

scholarly journals Designing VHDL to Simulate the Error Correction of Hamming Code

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
A. Mahmudi ◽  
S. Achmadi
Keyword(s):  
Error Correction ◽  
Error Detection ◽  
Forward Error Correction ◽  
Data Communication ◽  
Hamming Code ◽  
Data Errors ◽  
Quasi Experimental ◽  
Forward Error ◽  
Correct Data

The role of error detection and error correction for the data bit by the receiver is very important because the sender does not need to repeat the transmissions. Thus, the speed and reliability in transmitting data information can be maintained. This study aims to implement simulation the Forward Error Correction (FEC) method in verifying and correcting data errors received by using simulation. To support FEC method, study utilizes visual basic software so that it can be used as one of the quasi-experimental modules in the data communication laboratory. The Forward Error Correction (FEC) method is a method that can correct data errors in the receiver. This method uses simulated Hamming codes on the computer so that the detection and correction process can be clearly demonstrated on the monitor screen. This simulation can be used as a quasi-experimental module in a data communication laboratory. The simulation results show that the Hamming code (17, 12) codec has been running as expected.

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