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Game theory provides an adequate methodology for analyzing topics in communication systems that include trade-offs such as the subject of load balancing. As a means of balancing the load in the network, users are handed over from highly loaded cells to lower loaded neighbors increasing the capacity usage and the Quality of Service (QoS). The algorithm that calculates the amount of the load that each...
In this paper, a joint channel-and-queue-aware relay selection and resource allocation scheme at the scheduling phase in an OFDMA downlink cellular network is proposed. The scheme can choose the best relay to cooperate and allocate subchannels and power for the source and the relay for the selected packet which can maximize the proposed utility function waiting in the base station. Under the premise...
In this article, we present options for energy-efficiency in adaptive bit and power loading algorithm in practical OFDM systems with imperfect Channel State Information (CSI) and pilot-aided channel estimation. We consider rate-adaptive and margin-adaptive schemes always treating energy-efficiency as the key paradigm. The studies presented aim at lowering the energy-wastage related to pilot symbols...
A framework of joint antenna selection and source coding strategy for scalable video transmission over wireless systems was proposed. Each layer of a bit-stream could be switched among multiple transmit antennas in order to achieve unequal error protection (UEP) for prioritized video layered bit-streams. At first wavelet-based 3D ESCOT codec generates layered bit streams that need prioritized delivery...
In this paper we consider the uplink of a cellular network partitioned into localized jointly decoded cells. These jointly decoded cells are implemented as fixed size clusters. Such networks have a potential for real world deployments with improved spectral efficiency and user experience. Similar to conventional cellular networks, frequency planning can be considered as an efficient method to control...
The IEEE 802.16e standard provides a high degree of flexibility for setting up and operating mobile WiMAX networks in metropolitan environments. While the standard supports differentiated Quality of Service (QoS), crucial functions such as traffic scheduling and slot allocation are left as open issues to the research community. This paper focuses on these two features, that consist an NP-Hard problem,...
In this paper, a new joint scheduling and hybrid resource allocation method is derived and investigated for a multi-user downlink Orthogonal Frequency Division Multiple Access (OFDMA) system that provides Time Delay-Sensitive services (TDS) and Time Delay-Insensitive services (TDI). A three sectored multi-cellular heterogeneous traffic environment is considered where users are randomly distributed...
This paper presents a link adaptation strategy for non-binary LDPC code over a time-variant frequency-selective channel. The algorithm is based first on the adoption of waterfilling technique to wisely adapt the transmitted power. It is shown that as long as best subchannels are identified with the waterfilling algorithm, an equal power distribution can be applied with performance comparable to the...
For ad-hoc home networks without central coordinator, IEEE 802.11 systems merely support service differentiation. In many usage scenarios of a typical home network with applications requiring a strict quality of service (QoS), this MAC functionality is not sufficient. In order to counteract this problem, we developed in previous works a modified MAC scheme based on the IEEE 802.11 enhanced distributed...
In this paper, we focus on practical issues when implementing sleep mode in base stations. Our aim being to reduce energy consumption without affecting the Quality of Service (QoS) perceived by users, we expose some problems that my occur when applying sleep mode and propose practical solutions to cope with the resulting QoS degradation. We namely consider activation time issue that may result in...
The seamless integration of heterogeneous wireless access networks is currently one of the issues of major interest in the field of telecommunication systems. In an early future technologies like UMTS, WLAN and WiMAX will give broadband access to users that perform their voice/video calls or data sessions without knowledge of the specific technology their terminals are using, following the paradigm...
The problem of dynamic Quality of Service (QoS) management for multimedia services has been addressed from two complementary, yet interrelated directions; one mainly dealing with designing adaptive or “elastic” services, and the other, dealing with “smarter” resource allocation. We adopt this approach in this paper, by performing a graceful quality degradation and the corresponding resource (re)allocation...
In this paper, we proposes a resource reuse scheme for femtocell networks. In this context, macrocells operate in a Frequency Division Duplexing mode while all femtocells employ the macrocellular uplink spectrum in a Time Division Duplexing mode. We propose two solutions. In the first one, a centralized scheduling is performed via list-coloring based on the overall conflict graph. The second solution...
The rapid evolution of telecoms industry is accompanied by a huge increase of energy consumption of mobile networks, which forces the operators to exploit the potential of new techniques to save energy. In this paper, we propose a novel deployment strategy which is able to adapt itself to the spatial variation of the traffic by enhancing the cell radius in the low traffic areas, while the target quality...
In this paper, we propose a QoS tracking algorithm to support different QoS requirements to accommodate delay-sensitive and throughput-sensitive traffics in wireless mesh networks. The proposed scheme is carried out in a totally distributed manner by adjusting the minimum contention window size. Moreover, we investigate whether we can satisfy all QoS requirements in a stable manner through stability...
3GPP has specified that terminals can be configured to use either 2 or 10 ms transmission time interval in high speed uplink packet access systems. The purpose of this paper is to evaluate the benefit of exploiting a mixture of both of the transmissions time intervals within a cell instead of only one. The study is quantified by means of studying the achievable coverage of voice over IP and possible...
Since several years, communications between fixed and mobile units have been studied in areas in underground tunnels. The leaky feeder (LF) is one of the most useful results of these studies. The LF technology in combination with other communication systems allows us to reduce the transmission power of the mobile entities without sacrificing quality of service. Because the leaky feeder cables are...
Packet scheduling algorithms are viewed as one of the key mechanisms for increasing the diversity order, robustness and effectiveness of a wireless multi-user communication system. Traditional packet scheduling are mainly designed to increase the system capacity. In this paper we present a novel scheduling algorithm that improves the scheduling energy efficiency in OFDMA based wireless cellular networks...
Wireless mesh networks (WMNs) are comprised of nodes with multiple radio interfaces and provide broadband residential internet access or connectivity to temporal events. Our goal is to simplify the network deployment of such a mesh network, and towards that we are presenting procedures for automatic configuration and optimisation of the network. We first present an architecture framework that supports...
In two-tier networks consisting of a macrocell overlaid with femtocells in co-channel deployment and closed-access policy, spatial reuse is achieved at the price of severe cross-tier interference from concurrent transmissions. The lack of direct coordination between the macro and femtocells makes interference control as a challenging issue. Cognitive radio (CR) becomes a promising solution, where...
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