There have been researchers working on the design of coding-aware routing protocols to exploit the power
of network coding in static wireless ad hoc networks. However, most of them have overlooked the fact that routing decisions for multiple flows need to be coordinated in order to achieve maximum throughput. A mechanism to alter prior routing decisions is mandatory for this purpose. In this paper, we propose Self-recommendation coding-aware routing (SCAR), to provide such a mechanism. With intermediate nodes sensing the arrival of new flows, they can send self-recommendations to source nodes, triggering a route-change procedure. In the route-change procedure, adjustments are applied to the route metrics so that the newly recommended route can be fairly weighed without bias. A thorough analysis of coding structures is carried out, and a series of indicators are devised to predict how much throughput benefits we can gain from the mere knowledge of the topology. The rationale behind the protocol design and the effectiveness of the indicators are further justified by a series of simulations. Results show that SCAR can exploit coding opportunities better and provide higher throughput than other coding-aware routing protocols. It is also
shown that the opportunity of throughput gain is ubiquitous and it is tested on many typical topologies.

Jin Wang

Cenzhe Zhu

Teck Yoong Chai

Wai-Choong Wong

SCAR: A Coding-Aware Routing Protocol with Self-Recommendation in Static Wireless Ad Hoc Networks

In Long Term Evolution-Advanced (LTE-A), the signal quality in a wireless channel is estimated based on the channel quality measurements. The measurement results are used to select suitable modulation and coding scheme for each transmission, feedback, and processing delay, which can cause a mismatch between channel quality information (CQI) and current channel state at the base station. However, prospect delays in the reception of such CQI may lead to a system performance degradation. This study analyzes the impact of CQI feedback delay on joint user scheduling (JUS) scheme and separated random user scheduling (SRUS) scheme in LTE-A system over carrier aggregation. The analysis will be compared with the system having delayed channel and perfect knowledge at different deployment scenario. We will study the throughput performance of both scheduling schemes with different deployment scenario, and then recommend the suitable deployment scenario to keep the desired QoS for a specific number of users. Results show that, in main beam directed at sector boundaries and diverse coverage, JUS scheme performs better than SRUS, which can justify the intensive use of user equipment power and extra control signaling overhead.

Ahmed A. Ali

Rosdiadee Nordin

Mahamod Ismail

Huda Abdullah

Impact of Feedback Channel Delay over Joint User Scheduling Scheme and Separated Random User Scheduling Scheme in LTE-A System with Carrier Aggregation

The recent advances of ensemble mobile environment of smart devices with embedded sensors have enabled the MANET to play a key role in the smart cities as well as WSN and WMN. However, these smart devices are still limited in terms of energy, processor, and memory. Moreover, the efficient routing for reliable network connectivity at anytime, anywhere, and about everything is still a challenge in multihop wireless networks. This paper evaluates the QoS and energy efficiency of three active routing protocols: (i) OLSRv2, a successor to OLSR, (ii) DYMO, a successor to both DSR and AODV, and (iii) MP-OLSR multipath extension to OLSRv2. In contrast to the related previous works which focused only on CBR traffic without considering the influence of specific traffic types on the performance of routing protocols, this work focused on this area from a different perspective. It evaluates the performance of three internet-based traffic types that can be used in the smart city applications: VoIP, HTTP, and FTP using different simulation models. The impact of the network density, load traffic, and nodes mobility on the considered protocols was evaluated by considering particular performance metrics for each traffic application. Based on the results, the study concludes by presenting useful recommendations for future work.

Waheb A. Jabbar

On the Performance of the Current MANET Routing Protocols for VoIP, HTTP, and FTP Applications

This paper takes an exploratory look on control plane signaling in a mobile cellular core network. In contrast to most contributions in this field, our focus does not lie on the wireless or user-oriented parts of the network, but on signaling in the core network. In an investigation of core network data we take a look at statistics related to GTP tunnels and their signaling. Based on the results thereof we propose a definition of load at the GGSN and create an initial load queuing model. We find signs of user devices putting burden on the core network through their behavior.

Florian Metzger

Albert Rafetseder

Peter Romirer-Maierhofer

Kurt Tutschku

Exploratory Analysis of a GGSN&#x2019;s PDP Context Signaling Load

Contemporary nature of network evolution demands for simulation models which are flexible, scalable, and easily implementable. In this paper, we propose a fluid based model for performance analysis of reliable high speed networks. In particular, this paper aims to study the dynamic relationship between congestion control algorithms and queue management schemes, in order to develop a better understanding of the causal linkages between the two. We propose a loss synchronization module which is user configurable. We validate our model through simulations under controlled settings. Also, we present a performance analysis to provide insights into two important issues concerning 10&#x2009;Gbps high speed networks: (i) impact of bottleneck buffer size on the performance of 10&#x2009;Gbps high speed network and (ii) impact of level of loss synchronization on link utilization-fairness tradeoffs. The practical impact of the proposed work is to provide design guidelines along with a powerful simulation tool to protocol designers and network developers.

Suman Kumar

Lin Xue

Seung-Jong Park

Impact of Loss Synchronization on Reliable High Speed Networks: A Model Based Simulation

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Journal of Computer Networks and Communications - Table of contents 2014

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Journal of Computer Networks and Communications publishes original research and review articles that investigate both the theoretical and practical aspects of computer networks and communications.

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Journal of Computer Networks and Communications