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Accidents between battery-operated vehicles and pedestrians are expected to increase as electric vehicles (EV) or plug-in hybrid vehicles (PHV) are widely used in near future because of small ambient noise of EV/PHV. To prevent such accidents, a portable alert system for pedestrians to detect approaching vehicle is proposed in this paper. The alert system exploits ultra-wideband impulse radio (UWB-IR)...
It is heterogeneous wireless Networks (HWN) aggregation foundation for vertical handoff (VHO), and that is key characters of core technology for multi-network aggregation. The currently mechanism handoff trigger is analyzed, a best network selected (BNS) framework is designed, the parameters of network terminal and user terminal of effecting VHO algorithm, and which also include norm of capable parameters,...
Tele-health is an inter-disciplinary area where the delivery of health, medical information and services over large and small distances is possible by combining electronic information with communication technologies. Deaths from cardiovascular diseases have decreased substantially over the past two decades, largely as a result of advances in acute care and cardiac surgery. These developments have...
In this paper, a wideband, gain-flattened, highly-linear signal reconnaissance receiver worked on UAV with high sensitivity and high Dynamic range is proposed for complex electromagnetic environment of space and variable transmitter source. The reconnaissance receiver used field programmable gate array (FPGA) and some supporting chip and circuit to accomplish the frequency select and data storage...
In this paper, we investigate the performance of the Mobile Multi-hop Relay (MMR) uplink (UL) system with a non-transparent mode Relay Station (RS) which is used for coverage extension. We first develop analytical models to calculate the blocking probability and the utilization of the access zone in UL subframe. Based on that, the outage probability of the system is simulated. Performance is presented...
Future wireless access will involve a variety of integrated and interworking technologies. Depending on the conditions (e.g., the specific application, the quality of service requirements, the user mobility) each session will be served through the most suited access network; following some event, there will be a variation of the access technology, which is called vertical handover. Although the use...
In some frame-based OFDM applications such as WLAN and WMAN, the channel estimation is accomplished through the aid of the preamble. By means of the preamble, the estimated channel is only well applied under the assumption of a static channel status within the frame. If we consider a time-varying channel status in those applications, the channel tracking has to be performed without the aid of pilots...
The power consumption of wireless access networks will become an important issue in the coming years. In this paper, the power consumption of base stations for mobile WiMAX, HSPA, and LTE is modelled. This power consumption is related to the coverage of the base station. The considered technologies are compared according to their energy efficiency for different bit rates at a bandwidth of 5 MHz. For...
The focus of this paper is on the precoding and feedback strategies for a radio backhaul link between an access base station (ABS) and the hub base station (HBS) in the presence of mobile stations (MSs). In this paper it is assumed that the access and the backhaul links are simultaneous and use the same frequency band. Two feedback links are exploited at the ABS in order to optimize the communication...
The performance analysis of mobile-to-mobile (M2M) radio communications over double Hoyt fading channels perturbed by additive white Gaussian noise (AWGN) is considered. First, the probability density function (PDF) of the instantaneous signal-to-noise ratio (SNR) per bit is derived under the assumption that the fading channel is a concatenation (product) of two independent but not necessarily identically...
A base station (BS) transmits (Tx) and receives (Rx) signals to and from multiple mobile users (MU) through a two-way amplify and forward (AF) relay station (RS) using a two-phase protocol. The BS and the RS are both equipped with multiple antennas. In the first phase (time or frequency), the BS and all MU transmit their signals to the RS. In the second phase, the relay transmits towards the BS and...
We report on field trials using CoMP transmission in the downlink of a mobile radio network. Two new features enable over-the-air CoMP transmission from physically separated base stations and terminals. These are distributed synchronization and a fast virtual local area network. Using VLAN tags, terminals feed back the multi-cell channel state information to their serving bases where it is multiplexed...
We have already proposed a hybrid single-carrier (SC) and multi-carrier (MC) system for next-generation mobile communication system. A SC signal has low peak-to-average power ratio (PAPR), which yields high power output for wide coverage. A MC signal is robust against frequency-selective fading and has high data rate with quadrature amplitude modulation (QAM). By appropriately selecting SC and MC...
In this paper we analyze the Ricean K-factor for vehicle-to-vehicle (V2V) communications in a typical open sub-urban street crossing. The channel conditions vary from non line-of sight (NLOS) to line-of-sight (LOS). The antenna arrays used for recording the radio channels consist of 4 elements with directional radiation patterns. We measured 16 individual single-input single-output channels, with...
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,...
Open access is one of the access options for femtocell networks, where the mobile stations (MSs) are allowed to make hand-off to the femtocell base stations (fBSs) in their vicinity. In this paper, several performance trade-offs that are related to the deployment of open access femtocell networks are presented through computer simulations. In particular, first, impact of a capacity-based cell selection...
Future cellular mobile radio networks will exhibit a much more dense base station deployment than 2nd or 3rd generation communications systems, particularly with regard to traffic coverage. Hence, a significant increase in power consumption of cellular networks can be expected. In order to counter this trend, energy efficiency of such networks should be increased considerably. Concerning energy efficiency,...
This paper deals with mobile-centered decision making in heterogeneous networks, where intelligent mobile terminals take autonomous decisions about the JRRM actions, consisting to connect to one of the available systems. This distributed decision-making is possible due to Q-learning algorithms implemented within the mobile terminals that enable them to profit from their past experience in order to...
The concurrent transmission and reception of the signals in different frequency bands are required for the mobile terminals in IMT-Advanced systems to support spectrum aggregation systems. The authors have proposed a new transmitter architecture that enables the concurrent transmission of two separate frequency bands. The architecture is based on delta-sigma (ΔΣ) modulation, which converts a non-constant...
This paper presents a new blind symbol timing offset (STO) estimation scheme for wireless orthogonal frequency division multiplexing (OFDM) systems with constant modulus constellation. In the proposed scheme, the STO estimation is performed by minimizing the power difference between either adjacent or consecutive subcarriers, which basically depends on the assumptions made on the channel conditions...
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