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.
The given examples show that the standard 16-QAM Golay-Davis-Jedwab (GDJ) complementary sequences (CSs) cannot be yielded whenever the non-standard generalized Boolean functions (GBFs) are fed to Chong, et al's construction. Due to the fact that there exist a large number of the non-standard GBFs available, this paper focuses on the conversion from a non-standard GBF to 16-QAM CSs. By improving Chong,...
In this paper, we propose a method to analyze the scattering parameters for coupled microstrip lines with bend discontinuities. The key idea of the proposed method is to analyze the coupled bends and parallel coupled lines individually. Specifically, the equivalent π circuit model is built to approximate coupled bends and the corresponding scattering matrix is obtained by converting Z-matrix; the...
Mobile QQ is the smartphone version of the most popular IM software QQ in China. This paper studies the encipher system and communication protocol of mobile QQ and analyzes its security flaws. We found some security risks of mobile QQ and some of which are fatal especially in a weak wireless environment: Any attacker who could access the communication channel could easily recover the encrypted message...
To keep “Always-on”, terminals contact with remote servers by sending the keep-alive messages (or heartbeat messages). Any message in data plan can be sent if and only if the RRC (Radio Resource Control) connection1 is built. Keep-alive messages are transmitted periodically, which leads to periodic establishment of RRC connections in some cases. High frequency of state transition may induce heavy...
Cognitive radio is a promising technique in improving the utilization of wireless spectrum by spectrum sensing. However, conceivable spectrum sensing errors may deteriorate the quality of service provided for users. In this paper, we propose a framework to analyze the per-user throughput of both primary users and secondary users. Based on this framework, we further estimate how sensing errors influence...
The concept of mobile user equipment (UE) relay (UER) has been introduced to support the relaying transmission using device-to-device (D2D) communications for enhancing communication reliability. However, as the UER needs to use its own power for the other UE's data transmission, the D2D communication can be unfair to the UER. To overcome this issue, motivated by the recent advance in energy harvesting...
In this paper, we evaluate the outage probability and bit error rate (BER) performances of a three terminal full-duplex relaying (FDR) system with non-negligible residual self-interference (RSI). By investigating the signal-to-interference-plus-noise ratios (SINRs) at the relay and the destination respectively, the exact outage probability and BER of decode-and-forward (DF) based FDR system over Nakagami-m...
Fingerprint matching is adopted by a large family of indoor localization schemes, where collecting fingerprints is inevitable but all consuming. Recent studies show that the crowdsourcing scheme could be utilized to perform fingerprints collecting with desirable performance price ratio; however, since the fingerprints are collected from various mobile devices with crowdsourcing, it is difficult to...
Spectrum sensing data falsification (SSDF) attack are serious threats to collaborative spectrum sensing (CSS) of cognitive radio networks (CRNs). In this paper, inspired by EM (Expectation Maximization) method, we propose a scheme to estimate the presences of primary user (PU) and the SUs' operating point parameters (false alarm and detection probabilities) iteratively. The key features of the proposed...
Generalised Spatial Modulation (GSM) is a relatively new modulation scheme for multi-antenna wireless communications to further increase the spectral efficiency of Spatial Modulation (SM). There are two well-known Sphere Decoding (SD) algorithms tailored to SM: Receiver-centric SD (SM-Rx) and Transmit-centric SD (SM-Tx). In this paper, we show that the SM-Rx is applicable to GSM while SM-Tx is not...
This paper addresses the impacts of biasing and clipping on free-space optical (FSO) communications system over weak turbulence channel employing direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM). With atmospheric attenuation, turbulence and pointing errors, we present a statistical model for the optical intensity fluctuation at the receiver. The average bit error...
To overcome the inter-carrier interference (ICI) of orthogonal frequency division multiplexing (OFDM) systems due to the carrier frequency offset (CFO), an ICA-based carrier synchronization method is proposed. Independent component analysis (ICA) is also known as blind source separation (BSS), which depends on the independence of source signals to separate or extract latent signals of interest. In...
As a new Internet architecture, Named Data Networking (NDN) decouples location from the data itself to achieve security, scalability, and mobility. Although router-side data caching used in NDN reduces data acquisition delay, it introduces a new copyright protection challenge: how to prevent unauthorized users to retrieve data cached in routers that are out of the control of its publisher? Current...
We propose a time variation channel estimation method for the Time Division Duplex-Long Term Evolution (TDD-LTE) uplink in the high speed train (HST) environment. In the transform domain, based on the estimated channel parameters of the two block pilots, the generalized complex exponential basis expansion model (GCE-BEM) is firstly employed to estimate the channel parameters of the data symbols between...
In this paper, a load-based joint call admission control (LJCAC) scheme for heterogeneous wireless networks is proposed. The LJCAC scheme aims to achieving the load balance in heterogeneous networks as well as guaranteeing the quality of service (QoS) satisfaction. We also develop the analytical models to calculate the connection-level performance of the proposed LJCAC scheme in two typical heterogeneous...
We consider the source number estimation problem in the presence of unknown spatially nonuniform noise and underdetermined mixtures. We develop a new attractive source number estimator by replacing the covariance with the Fourth-Order (FO) cumulant of the observations. Furthermore, a Modified Minimum Description Length (MMDL) principle is proposed to reduce the divergence of the singular values corresponding...
In cognitive radio network (CRN), the utilization of wireless spectrum can be dramatically improved with the secondary user (SU) opportunistically access the licensed channels. With the help of spectrum sensing technology, the SU can dynamically access a large number of spectrum holes. However, how to allocate the spectrum holes between SUs becomes a thorny problem. The utilization of proper allocation...
In this paper, we propose a new cooperative diversity technique with radio frequency (RF) energy harvesting named dynamic harvest-and-forward (DHF) cooperation. This cooperation enables to obtain diversity gain with consuming neither extra energy nor extra bandwidth by exploiting the relay's proximity advantage over the destination. We analyze the proposed approach in terms of outage probability....
In this paper we propose an iterative interference cancellation scheme among base stations(BSs) for uplink cooperation transmission. For simplicity, we focus on a model with two BSs and two corresponding user equipments (UEs), and we derive the users selection criterion for successful interference cancellation(SIC). Our theoretic analysis shows that two round iterations are enough for distributed...
In this paper, we study user cooperation to enhance secure communication. Specifically, the source cooperates with intermediate nodes for secure information transfer when multiple eavesdroppers exist. We propose a three-step cooperative scheme, whereby the source selects partners and stimulates them for secure communications by paying an amount of reward. Specifically, a set of partners are selected...
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.