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In delay- and disruption-tolerant wireless communication networks, capacity is commonly traded off for delay. That is the case of spatial intermittent connectivity (SIC) networks. SIC networks are designed to provide high data rates to mobile nodes in small disjoint geographical areas. However, because of userspsila mobility, these high data rates come at the expense of significant connectivity delay...
Seamless IP mobility protocols like Fast Mobile IPv6 (FMIPv6) requires the knowledge of candidate access routers, to which the mobile node will hand over its connection to, well in advance while the mobile node is still connected to its current AR. The candidate access router discovery (CARD) protocol is one such protocol that provides the identity and capabilities information of the candidate access...
The media independent handover (MIH) architecture is designed to facilitate the signaling and enable seamless handovers in heterogeneous networks. In this paper, we propose a solution using the stream control transmission protocol (SCTP) to efficiently carry MIH messages. The solution uses SCTPpsilas multihoming and multistreaming capabilities along with cross-layer information available through the...
We present the design and performance of a new approach to packet switching for MANETs, which we call context aware protocol engines (CAPE). With CAPE, nodes disseminate information in the network by means of context-aware packet switching that enables the statistical multiplexing of bandwidth, processing and storage resources using integrated signaling covering channel access, routing and other functions,...
PESQ is the international standard for objective speech quality measurement and has been widely used in industry for voice quality assessment for VoIP products and systems. However, current research efforts involving PESQ are mainly focused on simulated IP networks. The need remains to establish how accurate PESQ is when used in real wireless systems, especially in new wireless VoIP environment. The...
Recently, a novel beamspace multiple input multiple output (BS-MIMO) transmission technique has appeared, which increases the spectral efficiency of open-loop communication systems while using compact antenna structures with a single radio-frequency (RF) front-end at the transmitter. In this paper, we extend the aforementioned architecture proposing an efficient limited feedback technique for capacity...
Multicell cooperative processing (MCP) has been recognised as an efficient technique for increasing spectral efficiency of future cellular systems. However the provided benefits come at the cost of increased overhead and computational complexity; Mobile Stations (MSs) need to feed back to their assigned Base Station (BS) their local channel state information (CSI) which in turn needs to be transmitted...
In this paper, we propose a novel mechanism for application of an IPv6 automatic address configuration technique to vehicular ad-hoc networks. The solution consists of combining standardized IPv6 schemes with geographic routing functionalities, which enables the matching of geographically-scoped network partitions to single IPv6 multicast-capable links. Unlike existing solutions described in this...
The problem of tandem vocoders and their effect on voice quality is well-known. In the case of international mobile-to-mobile calls, there can be up to three vocoding stages - between each mobile and its base station controller, as well as a digital circuit multiplication equipment (DCME) or voice over IP (VoIP) stages on the international link. The ITU standards for 2G and 3G networks define the...
Current Internet use is evolving, users are becoming mobile and are expecting data services on the go. This fact presents big challenges and opportunities to operators, which see the increase in data services as a big market still to be exploited. However, current cellular technologies cannot accommodate the demand that will arise when the true mobile Internet evolves. Addressing these challenges,...
In mobile access networks, base station (BS) assignment mechanisms are mainly driven by radio conditions since it is generally assumed that the limiting factor is the air interface. This assumption has been proven to be very reasonable when circuit voice was the dominant service and backhaul capacity provisioning accounting for the peak rate at the BSs was an economically feasible option. However,...
Cooperation in wireless communications is an attractive means to gain spectral efficiency or diversity. Typically, cooperation is studied at the level of an individual end-to-end link. On the other hand, the primary goal of the the protocol proposed herein is not the improvement of individual link quality, but rather to improve global resource utilization throughout the network in the context of a...
Mobile-to-mobile (M2M) fading channels in cooperative networks can efficiently be modeled using the multiple scattering concept. In this paper, we propose a new second-order scattering channel model for M2M fading channels in amplify-and-forward relay links under line-of-sight (LOS) conditions, where the received signal comprises only of the single and double scattered components. In the proposed...
The assignment of resources to the cells of a cellular mobile radio network is usually done by assigning certain parts of the total bandwidth to the cells. With the use of adaptive transmission, power can be considered as a resource and taking power into account in the assignment of resources to cells offers additional flexibility, especially in achieving efficient assignments and in adapting the...
This paper addresses the downlink performance of mobile WiMAX operating at 2.3 GHz in an urban environment. The analysis includes a comparison of simulated and experimental results. Simulated packet error rate (PER) versus signal to noise ratio (SNR) graphs are generated on a per link-speed basis using a fully compliant 512 carrier mobile WiMAX simulator. Experimental data is gathered using a carrier-class...
The recent proliferation of wireless devices extends the scope of mobile ad hoc networks (MANETs) applications beyond the military domain to include civil and commercial application scenarios. Since MANETs are composed of mobile terminals with limited resources, guaranteeing their security remains an unsolved and motivating challenge. Due to advantageous features like infrastructureless and spontaneous...
The authors considered applying cognitive radio to facilitate the efficient use of frequency resources over multiple radio links. They proposed a beam-switching scheme for radio links among inter-base stations and analyzed transmission performance characteristics by response time for Web browsing. The current modeling assumes mobile WiMAX transmissions to be a realistic and efficient form of broadband...
In multicarrier systems, the feedback information from a mobile station to a base station can be used to efficiently allocate the radio resource such as power and/or subchannels to a user. The quality of subchannel is measured by a signal-to-noise ratio (SNR), whose range, in a real system, must be quantized because channel information should be represented as a finite number of bits due to signaling...
In this paper, we extend the geometrical street multiple-input multiple-output (MIMO) mobile-to-mobile (M2M) channel model with respect to multiple clusters of scatterers as well as to frequency selectivity. The statistical properties of the proposed reference model are studied. Analytical solutions are provided for the three-dimensional (3D) space-time cross-correlation function (CCF), the temporal...
We review previous resource allocation algorithms for voice over IP (VoIP) services in Mobile WiMAX based on the IEEE 802.16e-2005 standard, and propose a new algorithm that allocates radio resources in the consideration of packet-size and packet-generation period variations of wireless VoIP codecs; hence, we can improve the efficiency of resource utilization in Mobile WiMAX. Through simulations,...
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