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In the past few years, the telecommunications field experienced a rapid evolution on two main grounds: Multiple mobile network interface terminals, and mobile radio technologies. The needs of the users in terms of flow and mobility are in constant increase, making it necessary to develop a new generation of networks. The latter would be a heterogeneous wireless environment in which different access...
When communicating at high-speed environment such as high-speed rail, the signals may encounter fast fading due to the terrain changes. In such communication environment, signal prediction can help improve the system throughput and reduce packet loss. In this paper, we propose a prediction mechanism called Window Weight Moving Average (WWMA) to predict the signal strength. We also analyze the real...
The integration of WiFi and WiMAX will allow a seamless connection between users for both connections with larger capacity, higher speeds and mobility access. A special router is needed to allow the interconnection between two different protocol network known as WiFi/WiMAX router. In this paper, we investigate and simulated based on the scenario using OPNET modeler simulation tools and compared their...
The mobile networks are continually evolving in order to support more users, to achieve higher data rates, and to provide new (multimedia) services. The next generation networks must be able to service heterogeneous traffic with diverse quality of service (QoS) requirements. Orthogonal frequency division multiple access (OFDMA) is important techniques for high data rate wireless multiuser communication...
Deploying FemtoCells in WiMAX network, also called WiMAX FemtoCell architecture, gains a lot of attention due to better indoor services can be provided and WiMAX network traffic can be shared by the FemtoCell. However, since the signal of WiMAX base station (BS) is stronger than FemtoCell Base Station (fBS), the handover procedure may not be triggered even though fBS is within the BS coverage. Besides,...
With the development of novel access technologies e.g. LTE, WiMAX etc., the mobile devices are able to establish services over multiple wireless connections with different momentary capabilities. Being imported from the fixed line communication, the current services deployed are lacking an efficient mechanism of adaptation to the momentary connectivity conditions, which deters the efficiency of the...
In this paper, we present a review of automatic repeat request (ARQ) and hybrid ARQ (HARQ) mechanisms implemented or proposed in beyond 3rd generation (B3G) wireless systems based on OFDMA. In particular, we will focus on part of the IEEE 802.16 standard family (IEEE 802.16-2005, IEEE 802.16m) and on 3GPP Long Term Evolution (LTE). In the second part of this overview, some performance curves show...
In this paper, we compare the capacities of WiFi networks in their different possible implementations. These implementations include hierarchical WiFi/WiMAX networks where WiFi APs are connected to the Internet using WiMAX links, and WiFi mesh networks where WiFi APs may play the role of routers that send packets to other APs, acting as Internet gateways. At the packet level, we model both WiFi and...
We investigates MAC layer performances of traditional RoF-based and newly emerging Pico BS-based WiMax networks. It is shown that the latter is preferred for the throughput and delay while the former has the merit of physical simplicity.
Wireless mesh networks (WMN) are considered an attractive alternative to the traditional wired backbone networks for broadband Internet access. However, their capacity is limited due to the nature of the radio channel, which must be shared by the nodes forwarding the traffic from and to the gateway. Therefore, estimating the capacity of WMNs is an important question. The capacity analysis proposed...
The last decade has seen explosive growth in the development of mobile applications. This has increased the demand on the wireless communication services. The capability to achieve wireless access anywhere, anytime, and anyplace has become common expectation as it provides significant flexibility and freedom in mobility. But to achieve global mobility in heterogeneous networks for any mobile device...
In this paper we propose a novel totally WiMAX-based architecture for large scale wireless broadband access. To provision scalable QoS, nodes' traffic should be managed locally. This is achieved through adding some gateway nodes which consequently leads to some cost. In order to realize the proposed architecture, intelligent node placement is primordial such the both cost and performance requirements...
The demand for the wireless Internet requiring broadband is expected to increase in a dramatic way due to popularity of tri player applications including voice, video, and data transmission. The existing wireless technologies UMTS, WiFi, WiMax, may not satisfy the customer requirements, for many reasons including availability, coverage, cost and most importantly mobility. Each technologies has it...
A low complexity, parallel, collision-free interleaver architecture for the WiMax duo-binary turbo decoder is presented. The proposed architecture dynamically adapts to different block sizes and it features reduced complexity resorting to parallel circular shifting interleavers. Moreover, it sustains a peak throughput of nearly 90 Mb/s with a 200 MHz clock frequency, when synthesized on a 0.13 μm...
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