Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 4 Articles
A new distance-aware broadcasting algorithm was proposed to enhance the propagation distance in the latency time of safetyrelated\nmessage broadcasting. The IEEE 802.11p standard states that if the medium is detected as idle, a station would defer its\ntransmission within a backoff time to avoid collisions with other stations.The backoff times follow uniform distribution over [0,\nCW]. In this way, fairness among all the stations can be guaranteed. However, propagation distance was ignored and in safetyrelated\nmessage broadcasting fairness is not the most important issue. In the proposed algorithm, the lengths of backoff times\nare generated from a nonuniform distribution.They are related with the distances between the source station and its forwarding\nstations.The farthest forwarding station has the highest probability to forwardmessages. Performance of the proposed algorithmis\nanalyzed by using a 2D Markov chain. Analytical and simulation results demonstrate that the proposed algorithm can enhance\nthe performance of safety-related message broadcasting in terms of propagation distance, which is reflected by the successful\ntransmission probability. The proposed algorithm does not need additional waiting time, RTS/CTS, and ACK, therefore having\nbetter compatibility with the IEEE 802.11p standard than earlier distance-aware algorithms...
This paper presents a model to predict video quality perceived by the broadcast digital television (DTV) viewer. We present how\nnoise on DTV can introduce individual transport stream (TS) packet losses at the receiver. The type of these errors is different\nthan the produced on IP networks. Different scenarios of TS packet loss are analyzed, including uniform and burst distributions.\nThe results show that there is a high variability on the perceived quality for a given percentage of packet loss and type of error.\nThis implies that there is practically no correlation between the type of error or the percentage of packets loss and the perceived\ndegradation. A new metric is introduced, theweighted percentage of slice loss, which takes into account the affected slice type in each\nlost TS packet.We showthat this metric is correlated with the video quality degradation.Anovel parametric model for video quality\nestimation is proposed, designed, and verified based on the results of subjective tests in SD and HD. The results were compared to a\nstandard model used in IP transmission scenarios. The proposed model improves Pearson Correlation and root mean square error\nbetween the subjective and the predicted MOS....
The three-dimensional Petersen-torus network 3PT is based on the Petersen graph and has recently been proposed as an\ninterconnection network. 3PT is better than the well-known 3D torus and 3D honeycomb mesh in terms of diameter and network\ncost. In this paper, we propose one-to-all and all-to-all broadcasting algorithms for 3PT(l; m; n) under SLA (single-link available)\nand MLA (multiple-link available) models....
Broadcasting in vehicular networks has attracted great interest in research community and industry. Broadcasting on disseminating\ninformation to individual vehicle beyond the transmission range is based on inter-vehicle communication systems. It is crucial to\nbroadcast messages to other vehicles as fast as possible because the messages in vehicle communication systems are often emergency\nmessages such as accident warning or alarm. In many current approaches, the message initiator or sender selects the node among\nits neighbors that is farthest away from it in the broadcasting direction and then assigns the node to rebroadcast the message once\nthe node gets out of its range or after a particular time slot. However, this approach may select a nonoptimal candidate because\nit does not consider the moving status of vehicles including their moving directions and speeds. In this paper, we develop a new\napproach based on prediction of future velocity and selective forwarding. The current message sender selects the best candidate\nthat will rebroadcast the message to other vehicles as fast as possible. Key to the decision making is to consider the candidates�\nprevious moving status and predict the future moving trends of the candidates so that the message is spread out faster. In addition,\nthis approach generates very low overhead. Simulations demonstrate that our approach significantly decreases end-to-end delay\nand improves message delivery ratio....
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