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In this paper, we propose a cooperative load balancing scheme focusing on improving effective resource utilization and mitigate the co-channel interference across domains through fair resource allocation in heterogeneous network (Het-Net). We models the load balancing issue as an optimization problem for minimizing the effective resource utilization. Simulation results have demonstrated that the system...
One of the essential usage of Intelligent Transportation Systems (ITS) applications is to provide road traffic information to vehicle drivers for road safety and efficient drive. For this usage, it is necessary to integrate geographical routing mechanisms in vehicular ad hoc network (VANET) into ITS applications. In this paper, we design and implement an ITS application which relies on IPv6 GeoNetworking;...
This paper proposes a channel-dependent adaptive spreading code selection method in downlink multicarrier code division multiple access (MC-CDMA). The proposed method is compared to the conventional MC-CDMA and orthogonal frequency division multiple access (OFDMA). First we show that the signal-to-noise and interference power ratio (SINR) after minimum mean squared error (MMSE)-based equalization...
Energy efficiency has become an important metric for the future system design. In traditional design methods, the link transmission strategies were investigated with only transmit power considered. We shall show in this paper that from the whole system's aspect, the radiated energy used for data transmission is only a portion of the overall power consumption, whose ratio depends on many practical...
Two new schemes are proposed for collision resolution in slotted ALOHA networks based on multi-user physical-layer network coding (MU PHY NC). In the proposed random access schemes, a collision of a generic number of packets can be recovered decoding the XOR of the original messages, such that the signal resulting from the collision is exploited rather than being discarded. Two different schemes that...
Adaptive bit and power loading is a constraint optimization problem with generally two cases of practical interest, where the objectives are the achievable data rate maximization (RM) and system margin maximization (MM) \cite{Ni-2008}. In this paper, we propose a different optimization model for underwater acoustic (UWA) channels, which is achieved by two algorithms: one is the bandwidth-efficient...
Road traffic congestion in urban areas and metropolitan cities is becoming nowadays an increasingly critical issue. With the advances in wireless technologies and the emergence of vehicle to vehicle communication techniques, new research studies are carried out to develop new applications and services over vehicular ad hoc networks for road safety and road traffic management. In this paper we present...
The signal to interference plus noise ratio (SINR) feedback has been utilized in random beamforming (RBF) to select users for the provision of service in multiple-input multiple-output (MIMO) systems. A large number of users are required to obtain the gain of multi-user diversity for a downlink transmission. However, if the number is not large enough, it may be difficult to obtain multi-user diversity,...
Energy efficiency is getting more and more emphasis in our everyday life. Wireless cellular networks use a lot of power and lately there have been intentions to create more efficient systems and so reduce the amount of consumed energy. In this paper we investigate the energy efficiency of single and dual RAT (Radio Access Technology) cellular networks. The proposed calculation scheme can be used to...
A distance based power control scheme is proposed and developed for application-controlled handover (ACH) in wireless personal area network (WPAN). In this paper, a power efficient communications in the wired wireless synergy network environment that consists of 3G (UMTS) + WiMAX + WLAN + WPAN (UWB) and optical network has been developed. This paper presents an enhanced power controlled transmission...
Inter-vehicle and roadside-to-vehicle communications can contribute to a safer and more efficient driving experience by providing time-sensitive and location-aware information. However, its performance suffers from vehicle mobility, intermittent user connectivity, and wireless channel unreliability. In this paper, we propose a novel cross-layer optimization approach based on our Adaptive Distributed...
This paper derives a simulation based comparison for UWBOFDM with different multipath channel models. Several multipath channel models such as (AWGN, Rayleigh and Rician) has been simulated and compared with a proposed hybrid combination of Rayleigh, Rician and AWGN to observe a realistic multipath faded environment. These cases are based on no fading and flat Rayleigh- fading, multiple-diversity...
This paper presents a double directional analysis of vehicle-to-vehicle channel measurements conducted in three different traffic scenarios. Using a high- resolution algorithm, we derive channel parameters like Angle-of-Arrival (AOA), Angleof- Departure (AOD), propagation delay and Doppler shift and identify underlying propagation mechanisms by combining these estimates with maps of the measurement...
In this paper, we propose a simple unevenness (bump/dent) detection system using a monocular camera to ensure safety of a handle type electric wheelchair and carry out the quantitative evaluation of a proposal system. In particular, the evaluation in two types of unevenness, three types of approach angle (90??a, 45??a, 0??a) against the unevenness and with or without of installation-calibration error...
In this paper, we develop optimal scheduling mechanisms for packet forwarding in Wireless Sensor Network, where clusterheads are gathering information with a predefined Quality of Service. The objective is to ensure balanced energy consumption and to minimize the packet loss probability, subject to time constraints (i.e. different nodes must send all their packets within a given time interval). Novel...
Through the introduction of Self-Organizing Net- works (SON) into mobile networks, a potentially large number of SON functions are available. These SON functions automatically perfom management actions. There will be SON functions for many aspects of fault, configuration, accounting, performance, and security (FCAPS) management. The functions are executed based on monitored network behavior, which...
A general path loss model for in-room radio channels is proposed. The model is based on experimental observations of the behavior of the delay-power spectrum in closed rooms. In such a room, the early part of the spectrum observed at different positions typically consists of a dominant component (peak) that vanishes as the transmitter-receiver distance increases; the late part decays versus distance...
Femtocells are envisioned to be deployed in indoor environments in order to improve both radio coverage and spectrum efficiency. This paper focuses on the self-organization of indoor femtocells, which includes mechanisms of cooperation. In this context, we propose a solution to automatically form cooperating groups among severely interfered femtocells in order to avoid interference. A hybrid access...
This paper investigates the performance of different low-complexity combining schemes in the context of dual-hop amplify-and-forward relaying networks. It is assumed that the relay uses single transmit (receive) antenna due to space limitation and to reduce the processing complexity. On the other hand, the transmitter and the receiver use antenna arrays to improve the overall diversity gain. However,...
IEEE802.11a/b/g Wireless LAN (WLAN) supports multiple transmission rates for packet transmission. In a mesh network backbone using WLAN, it is desirable to select and use an optimum transmission rate in order to achieve high throughput. Transmission rate can be set fixedly or adaptively. The former is further classified to link-based and node-based. In this paper, three transmission rate selection...
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