The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
With increasing implementation of broadband wireless networks and extensive deployment of multimedia services such as Video on Demand (VoD) or IPTV, the demand for video streaming applications will increase and more people will use their wireless devices to reach numerous video contents available in the Internet. Streaming real-time video in wireless networks is a challenging problem due to the stringent...
This paper proposes a mobile station (MS)-controlled fast MAC-layer handover (HO) scheme to reduce the HO latency in Mobile WiMAX. Based on the received signal strength (RSS) from any Base Station (BS), the MS can estimate its present distance from that BS. This capability allows the MS, through utilization of the broadcast messages by its Serving BS (SBS) and through few scannings of the Neighbouring...
Cognitive radio is a new communication paradigm that is able to observe, learn, optimize, and intelligently adapt to achieve optimal frequency band usage. Cognitive radio (CR)-based wireless mesh networks (WMNS) provide infrastructures for secondary users' transmission, and it is necessary to develop techniques with low interference to primary users in such networks. In this paper, we propose an interference-minimization...
This paper addresses the sampling jitter estimation and cancellation task in direct RF sub-sampling type radios. The proposed jitter estimation method is based on carefully injecting or superimposing an additional known reference signal to the received signal at the sampler input. Proper digital signal processing methods are then devised and applied to estimate the sampling jitter realizations from...
One way of modelling the wireless channel is in a statistical manner, based on a few parameters describing the characteristics of the environment. In most current wireless channel models, these key parameters are assumed independent between separate links, i.e. on the channels modelling the propagation between one base station and several mobile stations, or one mobile station and several base stations...
This work presents a novel approach for the avoidance of cross-tier interference in two-tier networks comprised of Orthogonal Frequency Division Multiple Access (OFDMA) macrocells and femtocells. This new technique is based on the use of Intracell HandOvers (IHOs), and it makes possible that either a macrocell or a femtocell can reassign its sub-channel or power allocation upon the detection of cross-tier...
In indoor environments, geolocation using Time of Arrival (TOA) estimation must use a wide bandwidth to overcome the effects of multipath propagation. Narrowband interference from other applications is a significant problem. In this paper we investigate a number of signal processing schemes to detect and overcome one or more relatively narrowband interferers. By making use of the limited time duration...
In this paper, we consider optimal power allocation (OPA) for distributed space-time coded two-way relay networks. Each relay transmits a scaled version of the linear combinations of the received symbols and their conjugates, and the scaling factor is based on automatic gain control (AGC) at the relays. We show that solving the OPA across relays to minimize the average conditional PEP of the destination...
In this paper, we introduce non-regenerative multi-group multi-way relaying. A half-duplex non-regenerative multi-antenna relay station (RS) assists multiple communication groups. In each group, there are multiple nodes that want to communicate with each other. Each node has a message and wants to decode the messages only from other nodes in its group. The required number of communication phases for...
In this work a cross-layer optimization in centralized Wireless Mesh Networks equipped with multiple antennas is introduced. A scenario has been considered in which multiple antennas at each node are employed to suppress the interference through beam-forming. By integrating different constraints from MAC and Network layers, a mathematical LP formulation is presented to minimize the system activation...
In wireless sensor networks, energy efficiency is achieved by making nodes sleep. In this paper, we propose SERENA, a node activity scheduling algorithm based on three-hop coloring. We study the performance of SERENA by simulating the conditions of a realistic environment including unidirectional links. The existence of unidirectional links causes color conflicts, which can be solved by exploiting...
In this paper, we propose a novel dynamic phase shift (DPS) scheme for energy efficiency in multi-hop wireless sensor networks. The DPS algorithm allows not only a receiver to shift its wake-up schedule dynamically to a sender's wake-up schedule, but also a sender to shift its wake-up schedule dynamically to a receiver's wake-up schedule to reduce the energy waste that occurs during a rendezvous period...
The challenge of our work is to enhance the effec- tiveness of Channel Quality Indicator (CQI)reporting schemes in multi-user OFDMA-based communication systems. Based on information theory, we propose a novel CQI reporting scheme that exploits instantaneous mutual information at the User Equipment (UE) in order to choose the best Physical Resource Blocks (PRBs) / CQI pairs to be fed back. While predicting...
Vehicular wireless communication should be able to provide vehicles with reliable and efficient data transmissions for various applications, especially safety applications. We present a dedicated multi- channel MAC protocol that has an adaptive broadcasting mechanism, specifically designed to provide collision-free and delay-bounded transmissions for safety applications under various traffic conditions...
This paper considers wireless spectrum sensing in harsh environments dominated by shadowing and fading. By modeling the network of the secondary users as Markov random fields and pulling a group of secondary users to cooperate through distributed probabilistic inference, effective sensing and fusion can be achieved. The proposed framework subsumes belief propagation, as well as conventional weighted...
With widespread use of multimedia communication, quality of experience (QoE) progressively becomes an important factor in networking today. Besides, multimedia applications can be supported under various technologies, including wired and wireless networks. Among them, Universal Mobile Telecommunications System (UMTS) is one of the most popular technology thanks to its support on mobility. Improved...
With the increasing throughput demands of wireless users, operators will need to build wireless networks with significantly larger capacities than those presently available. Therefore for the next generation of wireless networks (4G) a significant effort is being placed on increased spectral efficiencies. One means of achieving higher spectral efficiencies is through the use of Distributed Antenna...
In this paper, we study the transmit precoding problem for multiple-input multiple-output (MIMO) multiple-access (MA) cellular systems employing cooperative base stations (BSs) and amplify-and-forward (AF) relaying where the antennas at the user equipments (UEs), relay terminals (RTs), and BSs are correlated. It is assumed that BSs have perfect channel state information (CSI) while user equipments...
The present day challenge during emergency response is the lack of availability of latest and detailed information to the emergency personnel about the incident scene. The success of the fire mission planning depends critically on the ubiquitous availability of high-quality information (e.g., building plans, aerial photos, hazardous material databases, medical patient data) while the fire fighters...
In this paper, we study the problem of joint carrier frequency offset (CFO) and channel estimation for two-way relay network (TWRN). We consider the frequency selective fading channels and adopt the zero padding (ZP) based orthogonal frequency division multiplexing (OFDM) as the modulation of the transmission. Due to the mixture of the first and the second transmission phases, the joint estimation...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.