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The current trend in telecommunications services provisioning is shifting toward global ubiquitous networking and unified service architecture. Given the diversity of access technologies, this global ubiquitous networking cannot be possible without efficient interworking between the different access players. This leads to the necessity of defining, implementing, and deploying common services control...
We design novel mechanisms and algorithms for fast, simple, and distributed interference management and scheduling in wireless femto networks via exchange of information over-the-air (OTA). We focus on Long Term Evolution (LTE) of the 3GPP standard and on the downlink; we leverage the existing signalling in LTE and delineate additional signals that are needed. Key aspects of our work include: (1)...
As the interests of broadcasting services in mobile networks are increased, the research of convergence services of broadcasting and communication has become popular. To support broadcasting services in cellular network smoothly, WiBro support the multicast and broadcast service (MBS). MBS is transmission method that base stations belong to same MBS zone transmit the data to all users who request...
Single-carrier frequency division multiple access (SC-FDMA) with iterative multiuser detection, called grouped FDMA (GFDMA), allows several users to share a common set of subcarriers. In order to improve user fairness and guarantee quality-of-service (QoS) of users who share subcarrier sets, we propose a proportional fair (PF) scheduling algorithm satisfying QoS constraints. For each user selection...
To further increase the spectrum efficiency of cellular mobile communication systems, it is important to control co-channel interference among cells. To control co-channel interference and improve spectrum efficiency over the whole cell, we proposed QoS-guaranteed multi-cell coordinated transmit power control, which limits the communication of some users and fully guarantees the QoS for the remaining...
Block diagonalization is a linear precoding technique which eliminates the multi-user interference at the transmitter side by creating parallel orthogonal single user links. In this technique, the transmit diversity order is fixed for each user and only power can be controlled to satisfy SINR requirements. This restricts the degrees of freedom available for resource allocation and limits the energy...
In this paper, we compare the performance attained by several scheduling policies when the resource allocation is performed in a per-user or in a per-frequency resource ordering. We test the capability of both approaches to deal with the quality of service (QoS) provisioning in a multi-service scenario in a mobile OFDMA network. We probe that the comparative performance of these two approaches depends...
Femtocell systems are providing cost-effective high-bandwidth service in wireless cellular systems under very low transmission power compared to macro-cell. Normally, conventional handoff algorithms can't well satisfy the mobility in hierarchy networks because of femtocell's characteristic. Therefore a user's state and SINR-based handoff (SINR-US) algorithm from macrocell to femtocell under the consideration...
This paper extends the discrete Verhulst power equilibrium method, previously suggested in to the power-rate optimal allocation problem. Multirate users associated with different types of traffic are aggregated to distinct user' classes, with the assurance of target rate allocation per user and QoS. Therein, single-rate Verhulst power allocation algorithm was adapted to the multirate DS/CDMA power...
This paper addresses the issue of wireless resource allocation of a Mobile WiMAX cell based on OFDMA access technique. We compare two strategies: the MAX SNR which is the most used channel assignment technique and our proposal which is based on channel condition learning. As we distinguish four IEEE 802.16e-2005 service classes: UGS, rtPS, nrtPS and ErtPS, we combine these strategies with a scheduler...
In cellular systems, one of the most significant metrics to measure quality of performance is the average number of call drops in a system. Hand-off mechanism ensures that the active calls in the system are successfully completed without being dropped in the mid communication. This seamless connectivity is achieved as the user moves around transferring active calls from one base station to another...
In this paper, we quantify the expected symbol loss probability in mobile multi-hop relaying systems employing Orthogonal Frequency Division Multiple Access (OFDMA) Techniques. We obtain the expected number of collisions and calculate the probability of symbol loss when a conflict occurs between subcarriers of two or more non-transparent relay stations, as well as we calculate the average symbol loss...
Advanced simulation tools have taken a lot of attention for development and analysis of new and existing protocols and technologies in wireless communications. The huge amount of information, protocols and techniques to be analysed make however their implementation difficult in one simulator. It is thus of paramount importance to define a common interface between the different layers in order to simplify...
In the heterogeneous wireless networks, the optimal network selection problem is one of the key issues. QoS aware path selection scheme is proposed in this paper, which estimates required bandwidth ratio based on the QoS requirements of target service and the SINR of each path. The proposed scheme can select the optimal path which can satisfy the QoS requirements among many heterogeneous wireless...
A new Virtual Base Station (VBS) election technique is proposed by this paper to help in QoS provisioning in the infrastructure-less Mobile Ad-hoc Networks referred to as MANET. This VBS election technique is based on the mobile node's Signal-to-Noise Ratio (SNR) and has been applied on the MANET's hybrid routing protocol: The Zone-based Routing Protocol. The developed routing protocol will be referred...
Power control is one of the major parts of cellular communication system. The power control helps maintain quality of service of the communication link. In this paper, a simple proportional integral (PI) control is used in the Code Division Multiple Access (CDMA) radio system to maintain the signal to noise ratio (SNR) around a desired level under channel fading environment with multiple access interference...
The deployment of real-time and multimedia applications over wireless LAN has gained a growing interest in this last decade. These applications, e.g. video streaming, require tight guarantee on quality of service (QoS). Also, they use multicast communication in order to reduce the bandwidth consumption. However, in WLAN, multicast packets are sent with the basic rate (lowest rate); which results in...
Vertical handover (VHO) techniques are applied when mobile users require service continuity and a seamless roaming between heterogeneous networks. A VHO decision can be taken on the basis of physical parameters, such as the received signal strength (RSS), data rate and signal-to-interference and noise ratio (SINR). In this paper, we compare three VHO decision criterions, each of them based on different...
In IEEE 802.16e OFDMA system, the system capacity for accommodating VoIP traffic with small-sized PDUs is severely reduced due to a large amount of signalling overhead. In order to mitigate this problem, the IEEE 802.16 maintenance group has recently proposed a persistent allocation scheme to increase the voice over IP (VoIP) system capacity. However, it is difficult to use the conventional modulation...
Recently, there has been much effort to integrate heterogeneous wireless technologies in order to make overlay networks able to provide mobile users with ubiquitous Internet access. Handover management is still one of the most challenging issues to be solved for seamless integration of wireless networks. In this paper, an algorithm for vertical handover with QoS guarantees between IEEE 802.16e and...
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