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In Distributed WiMAX Mesh Networks (DWMN), a joint solution with FEBA (Fair End-to-end Bandwidth Allocation) and DRR (Deficit Round Robin) can be used to achieve high end-to-end throughput fairness. Even then, the higher the number of hops a traffic flow traverses, the longer becomes the end-to-end delay of the traffic flow. This will result in serious unfairness of service quality among real-time...
This paper intends to propose a novel handover algorithm to balance the load of the layers in a multi-reuse scenario. Each layer works independently from each other and it has its own scheduling process, coverage and mobile stations attached. The algorithm proposed balances the resources among layers by moving mobile stations from one to another layer according their QoS requirements and channel condition...
Based on considering the CODEC frame duration, this paper proposes a superior uplink scheduling algorithm that can efficiently support multiple DTX VoIP CODECs over M-WiMAX, and be able to facilitate the uplink resource wastes during silence period and optimize the system VoIP capacity. The BS uplink resource allocation procedure is planned and adapted according to the reserved bit in the Bandwidth...
The IEEE 802.16/WiMAX mesh standard is a promising technology to support next generation wireless broadband metropolitan area networks. The medium access control (MAC) layer of IEEE 802.16 mesh supports both centralized and distributed scheduling mechanisms. The coordinated distributed scheduling mechanism uses a pseudo-random election algorithm to determine the transmission times of the nodes. The...
This paper proposes an efficient uplink scheduling algorithm that can perfectly support various VoIP CODECs with VAD/DTX/CNG in M-WiMAX considering the variants of silence duration between different voice users, solving the problems of uplink resources wastes and overwhelmingly large overhead that caused during silence period. In our proposed algorithm, efficient schemes is proposed to implement the...
This paper presents some experimental results about the robustness of a WiMAX system against interfering signals. In particular, this work presents a WiMAX performance comparison when two different types of interfering signals were generated: a continuous wave and a rectangular pulsed wave. Both of them were tuned at the same working frequency of the WiMAX system (i.e. 2.55 GHz). The former is typical...
Informing users about new resource assignments has to be broadcast, thus generating a substantial amount of the mapping overhead that influences the system throughput. In particular, the performance of voice-over-Internet protocol (VoIP) services is seriously affected by the mapping overhead because the VoIP packet size is small. In order to reduce the mapping overhead, a semi-fixed mapping scheme...
As advanced integrated network architecture, ldquocognitive radio technologies,rdquo which aim to improve the spectrum efficiency, have been studied. In the cognitive radio networks, each node recognizes radio conditions, and according to them, optimizes their wireless communication routes with the integration of the heterogeneous wireless systems not only by switching over them but also aggregating...
The paper presents a network scenario for multimedia communications during emergency operations in a sea area. The network scenario is composed by a satellite link and a WiMAX system provided by a main naval unit. The WiMAX system permits the communications between the operators on small units and the main naval unit, where there are both local coordinators and the shared satellite link, used for...
Self similar behavior of the aggregate traffic is a well known issue in the networking area. In this paper, we first study the self similarity of the empirically aggregated VoIP traffic in a heterogeneous wireless network testbed environment and then model it using Fractional Gaussian Noise (fGn). The heterogeneity of the environment is provided by exploiting different wireless technologies in backbone...
In this paper, we consider the service of voice over internet protocol (VoIP) traffic with the service of non-real time traffic in the mobile WiMAX system. VoIP traffic is delay-sensitive and requires transmission at an almost constant rate. As a consequence, it may require a large amount of resource when users are in poor channel condition, leading to resource outage problem. To alleviate this problem,...
IEEE 802.16, popularly known as WiMAX, is one of the most innovative methods developed in recent times to address growing demand for high-speed wireless broadband networks. This paper addresses the problems concerning the delivery of video packets in video conferencing and other multimedia application services over WiMAX. Multiple competing traffic sources over a point-to-multipoint WiMAX topology...
Multi media stream service provided by broadband wireless networks has emerged as a important technology and has attracted much attention today. Due to its large coverage area, low cost of deployment and high speed data rates, WiMAX is a promising technology for providing wireless last-mile connectivity. Physical and MAC layer of this technology refer to the IEEE 802.16e standard, which defines 5...
There are several uplink scheduling algorithms in IEEE 802.16 systems, such as unsolicited grant service (UGS) and real-time polling service (rtPS), which can be used for voice over IP (VoIP) services. But these algorithms have a problem of energy wasting. To solve this problem, we propose an energy saving based uplink scheduling algorithm for VoIP services. Then we analyze the performance of the...
IEEE 802.16 standards define the power saving of class (PSC) II to save energy for voice over IP (VoIP) services. But the system performance, such as throughput and delay, is affected by load imbalance caused by the parameter setting of sleep mode of VoIP users. To solve this problem, we propose a strategy to balance the load. We arrange the sleep cycle of each VoIP user alternately in this strategy...
We present active measurement results from a commercial IEEE 802.16/WiMAX-based network, with primary focus on TCP performance. We compare four TCP variants, namely New Reno, Cubic, Vegas and Veno, using throughput, round-trip time (RTT), and retransmission rate metrics. While all TCP variants achieve similar throughput, they do so in different ways, with different impacts on the network performance...
Despite the significant interest in WiMAX technology and deployment, there are very few publicly reported measurements from testbeds and field trials. As such, most WiMAX studies employ simulation and modeling. This paper contributes to our understanding of what is realistically possible using off-the-shelf fixed WiMAX equipment today. We employ multiple competing traffic sources over a point-to-multipoint...
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