Scheduling real-time traffic with deadlines over a wireless channel

Author(s):  
Sanjay Shakkottai ◽  
R. Srikant
Author(s):  
Maode Ma ◽  
Jinchang Lu

Quality of service (QoS) provisioning is an important issue in the deployment of broadband wireless access networks e.g. WiMAX (IEEE Std 802.16-2004, 2004) networks with real-time and non-real-time traffic integrated. To design a QoS support framework tailored for WiMAX networks is more challenge as wireless channel has unique characteristics such as time-varying channel and limited channel capacity. This chapter presents various QoS support mechanisms in WiMAX networks. Existing proposals with the state-of-the-art technology have been classified into three main categories: QoS support architecture, bandwidth management mechanism, and packet scheduling schemes. Representative schemes from each of the categories have been evaluated with respect to major distinguishing characteristics of the WiMAX MAC layer and PHY layer as specified in the IEEE 802.16d standard. Suggestions and research trends on QoS support in WiMAX networks are highlighted.


Author(s):  
Mohammed Mahfoudi ◽  
Moulhime El Bekkali ◽  
Abdellah Najid ◽  
Mohamed El Ghazi ◽  
Said Mazer

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Rusmadi Suyuti

Traffic information condition is a very useful  information for road user because road user can choose his best route for each trip from his origin to his destination. The final goal for this research is to develop real time traffic information system for road user using real time traffic volume. Main input for developing real time traffic information system is an origin-destination (O-D) matrix to represent the travel pattern. However, O-D matrices obtained through a large scale survey such as home or road side interviews, tend to be costly, labour intensive and time disruptive to trip makers. Therefore, the alternative of using traffic counts to estimate O-D matrices is particularly attractive. Models of transport demand have been used for many years to synthesize O-D matrices in study areas. A typical example of the approach is the gravity model; its functional form, plus the appropriate values for the parameters involved, is employed to produce acceptable matrices representing trip making behaviour for many trip purposes and time periods. The work reported in this paper has combined the advantages of acceptable travel demand models with the low cost and availability of traffic counts. Two types of demand models have been used: gravity (GR) and gravity-opportunity (GO) models. Four estimation methods have been analysed and tested to calibrate the transport demand models from traffic counts, namely: Non-Linear-Least-Squares (NLLS), Maximum-Likelihood (ML), Maximum-Entropy (ME) and Bayes-Inference (BI). The Bandung’s Urban Traffic Movement survey has been used to test the developed method. Based on several statistical tests, the estimation methods are found to perform satisfactorily since each calibrated model reproduced the observed matrix fairly closely. The tests were carried out using two assignment techniques, all-or-nothing and equilibrium assignment.  


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