Browsing by Author "Şafak, A."

Now showing 1 - 6 of 6

Citation - WoS: 1
Citation - Scopus: 2
Alternative Enhancement of Associativity Based Routing (Aeabr) for Mobile Networks
(Springer, 2010) Preveze, B.; Şafak, A.
This study proposes an alternative enhancement for the Enhanced Associativity Based Routing (EABR) method which is a derivation of ABR (Associativity Based Routing) by relative speed and relative distance estimation using the received power strength (RPS) of the nodes. In this study, it is shown that EABR outperforms some other well known protocols. The performance of EABR is improved in terms of number of route reconstructions (RRC) and connected status percentage (CSP). Message overhead and bandwidth utilization is also investigated. © 2010 ICST Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering.
Analysis of delay factors for voice over WiMAX
(IEEE, 2008) Şafak, A.; Preveze, B.; 17573
This paper presents the results of our computer simulation for delays experienced by voice packets over WiMAX 802.16e protocol running over an enterprise packet network connected to public internet. In the simulation we analyzed the effect of packet size, core network link speed, internet service provider link speed, wireless network link speed, wireless distance, base station range, and distance in internet parameters that effect the amount of delay in a WiMAX embedded IP network. In this study, all the delay parameters are fixed to their default values and current parameter values are changed so that the delay is varied between minimum and maximum values in uniformly distributed 100 steps and the delay is plotted in each step. Total fixed delays can be considered as minimum delay and variable delay corresponds to the maximum delay that can occur under the given conditions. All other fixed and variable delay parameters such as switching delays, packetization delays, contention delays and the delays caused by buffers etc. are also taken into account. The results indicate that among these delays WiMAX base station range and the number of base stations play the most decisive role.
Citation - Scopus: 2
Associativity Tick Averaged Associativity Based Routing (Ataabr) for Real Time Mobile Networks
(2009) Převeze, B.; Preveze, Barbaros; Şafak, A.; 17573; Elektrik-Elektronik Mühendisliği
This study proposes a long lived routing method which is also based on Associativity such as ABR (Associativity Based Routing) for real time applications. The main purpose of our work is improving the ABR algorithm in order to reduce the outage of the nodes and decreasing the number of reconstructions required to keep the nodes in communication. The performance of ABR is compared with other long-lived relay selection algorithms for real-time applications.
Citation - Scopus: 0
Comparison of ant colony and fastest path algorithms for fixed and variable number of nodes in multi-hop networks
(2010) Preveze, B.; Preveze, Barbaros; Şafak, A.; 17573; Elektrik-Elektronik Mühendisliği
In this study, the fastest path algorithm which is known as a routing method from source to destination and Ant colony method which is known to be adaptable to the dynamic changes in the network are compared for average hop counts, power consumption and packet arrival delays by implementing a mobile network simulation. Even the average hop counts for both algorithms reach to almost same value at the simulation results, since it is seen that the fastest path algorithm provides less packet delay and less power consumption with respect to Ant colony algorithm , it is thought that fastest path algorithm may be more useful than Ant colony algorithm for real time voice or video packet transmissions. ©2010 IEEE.
Citation - Scopus: 0
Fair spectrum sharing in wireless networks
(2011) Preveze, B.; Preveze, Barbaros; Şafak, A.; 17573; Elektrik-Elektronik Mühendisliği
Efficient utilization of available resources and the avoidance of overload conditions have high importance for any communication network. For a CSMA based VANET the wireless bandwidth must be shared fairly among all nodes. In VANET the network and available bandwidth are in dynamical structures. Thus, if the congestion control is not provided for the VANET based broadcast communication; the lower priority applications may use the entire spectrum and may cause starvation of some important applications. In this work it is shown that our proposed MCAF (Most Congested Access First) throughput improvement method also provides fair data rate per node in vehicular communication. The data rate per node with fair spectrum allocation is determined using the MCAF simulation and calculation results. Finally, the evaluated results are confirmed by comparing them with the results of other works evaluated in the literature. © 2011 IEEE.
Citation - Scopus: 0
Power consumption of novel throughput improvement methods
(2010) Preveze, B.; Preveze, Barbaros; Şafak, A.; 17573; Elektrik-Elektronik Mühendisliği
The novel proposed method as a combination of Time Division Multiple Access (TDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) called Orthogonal Frequency Division Most Congested Access First (OFDMCAF) provides spectrum sharing, buffer management and improves the throughput. In this work the power consumed by activating each cognitive method is analyzed in addition to the throughput improvement provided by each method used with OFDMCAF. It is shown at the end of the analysis that activation of each method also decreases the average power consumption even the same routing algorithm is used in all cases.