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This paper introduces a frequency synchronization method applicable to multiple access in direct spectrum division transmission (DSDT). In the transmitter (Tx) side, DSDT divides the single carrier modulated signal into multiple sub-spectra and assigns them to unused frequency resources. In the receiver (Rx) side, the divided sub-spectra are recombined and the single carrier modulated signal is regenerated...
This paper studies a robust beamforming optimization problem of minimizing total transmit power in a distributed manner in the presence of imperfect channel state information (CSI) in multicell interference networks. Due to the fact that worst- case is a rare occurrence in practical network, this problem is constrained to satisfying a set of signal-to-interference-plus-noise-ratio (SINR) requirements...
This paper aims to present a methodology and a set of tools that could be used in order to check the validity of an Intelligent Transport System. These tools will consider each ITS component, i.e. C-ITS- R (Road Side Units) RSU, C-ITS-V (On-Board Unit) OBUU, C-ITS-C (Central Server) with its specific fea- tures as location precision for an OBU and adequate forwarding of dangerous events for an RSU...
Hardware calibration is a necessary procedure to establish the reciprocity of the uplink (UL) and downlink channels (DL) in a time division duplex (TDD) mode of operation. In practice, any calibration scheme is prone to errors. Such errors result in a residual mismatch between UL and DL channels, which, in turn, can significantly affect the quality of DL transmission. In this paper, we study the effects...
Sweep coverage is an important problem in wireless sensor networks. With sweep coverage, more Points Of Interests (POIs) can be monitored with fewer mobile sensor nodes thanks to the mobility of the nodes. Most existing studies on sweep coverage focus on the trajectory of the mobile sensor nodes to guarantee the sweep coverage of the POIs. Considering the fact that, in many applications, the collected...
In this paper we present our latest findings on dynamic user-centric scheduling for a flexible 5G radio design, capable of serving users with highly diverse QoS requirements. The benefits of being able to schedule users with different transmission time intervals (TTIs) are demonstrated, in combination with a user-centric multiplexing of control and data channels. The proposed solution overcomes some...
In this paper, we investigate the performance of spatial modulation (SM) for vehicle-to- infrastructure (V2I) and vehicle-to-vehicle (V2V) communications over a generalized multiple scattering channel. This channel model provides a realistic statistical description of an intervehicular communication environment and includes as special cases the Rician, Rayleigh, and double-Rayleigh channels. We derive...
This paper investigates the performance of bidirectional dynamic networks (BDN) with massive multiple input multiple output (MIMO) systems. In BDN, dynamic allocation of the number of uplink and downlink remote radio heads (RRHs) is proposed, which offers a flexible solution to balance the data traffic asymmetry without requiring the time synchronization. Intuitively, the interference between the...
As the explosion of Internet traffic is quickly leading to overloaded cellular network, device-to-device (D2D)-based content sharing is proposed as a method to offload mobile data traffic. The performance of D2D-based content sharing is dramatically affected by the success rate of content fetching from nearby devices and quality of content transmission, which is determined by the geographic distribution...
In cloud market, cloud providers offer diverse service options, including on-demand instances and reserved instances. Generally reserved instance price is cheaper than on-demand instance, but excessive reservation may result in high capacity underutilization. To improve resource utilization rate and reduce providers' service cost, a steady broker federation is necessary to propose. Broker federation...
Data-driven solutions to Electric Vehicle (EV) range estimation is attracting attention recently due to the prevalence of Internet of Things (IoT). However, there raise the Big Data problems with the increased volume and number of sensory sources of unstructured data collected from the EV equipped with In-Vehicle Networks. This means that traditional statistical analysis and Machine Learning tools...
Millimeter wave multiple-input multiple-output (MIMO) communication systems must operate over sparse wireless links and will require large antenna arrays to provide high throughput. To achieve sufficient array gains, these systems must learn and adapt to the channel state conditions. However, conventional MIMO channel estimation can not be directly extended to millimeter wave due to the constraints...
Traffic safety and efficiency are the most important motivations for the rapid development of vehicular ad hoc network (VANET) technology. VANET is considered to provide the unified platform and solutions for the intelligent transportation system (ITS). In this paper, a novel method named spectrum penetration is proposed to improve the throughput of multi-channel MAC for VANET. Meanwhile, it can overcome...
This work introduces MultiSphere, a method to massively parallelize the tree search of large sphere decoders in a nearly-independent manner, without compromising their maximum-likelihood performance, and by keeping the overall processing complexity at the levels of highly-optimized sequential sphere decoders. MultiSphere employs a novel sphere decoder tree partitioning which can adjust to the transmission...
We present a multi-user multiple-input multiple-output (MIMO) cognitive radio system consisting of a secondary receiver that deploys spatial multiplexing to decode signals from multiple secondary transmitters, under the presence of primary transmissions. The secondary receiver carries out minimum mean-squared error detection to decode the secondary data streams, while it performs spectrum sensing...
Mobile cloud computing is increasingly being used in recent times to offload parts of an application to the cloud to reduce its finish time. However, quality of offloading decisions depend on network conditions and hence many offloading solutions assume that MAC layer retransmissions will tackle transient frame errors. This can lead to suboptimal solutions, as well as, degrade service level guarantee...
Doze mode, which was introduced from Android 6.0 aiming at reducing battery consumption when the device is unused for a long time. This work firstly reveals the internal details of the battery-saving feature, especially about the state transitions. Furthermore, we discover several defects in Android's device drivers associated with doze mode. By exploiting the defects, we implement various proof-of-concept...
Wireless caching at users' devices in mobile social network is considered to be a promising solution to alleviate backhaul overload in future wireless networks. However, most of the current works propose caching schemes based on heuristic reasoning and intuition with poor performance or high complexity which are impractical due to individual devices' computing capacity restriction. In this paper,...
Twitter is attracting significant interests from the research community in the last few years. Sentiment analysis of tweets is among the hottest topics of research nowadays. State of the art approaches of sentiment analysis present many shortcomings when classifying tweets, in particular when the classification goes beyond the binary or ternary classification. Multi-class sentiment analysis has proven...
Software Defined Networks (SDN) provide a high simplification of the network management by decoupling the control plane from the data plane through the use of controllers. Distributed-Denial-of-Service (DDoS) attacks can make SDN controllers unavailable to process legitimate flow requests from switches. The main approaches to protect controllers against DDoS attacks are essentially based on the attack...
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