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 multi-band orthogonal frequency division multiplexing (MB-OFDM) is an ultra wideband (UWB) technology that can transmit information at the maximum data rate of 480 Mb/s. When the simultaneous operating piconets (SOP) are located closely, the symbol collisions are expected to occur among the symbols transmitted over the same sub-band at the same time. This interference will decrease throughputs...
Cooperative communication usually shares a common model-one source, several relays and one destination. In this paper, we consider the multi-source scenario in a cell to carry on cooperative communication. However, multi-user setting might causes interference in the network, given this interference, the process of relaying selection applies SINR (signal to interference noise ratio) as a criterion...
In this paper, we consider blind interference suppression in IR UWB communication system, and the means of a statistical technique called independent component analysis (ICA), taken as a solution for the coexistence of impulse-radio Ultra-wideband (IR-UWB) systems with other wireless systems was studied. Particularly for the evaluation of the system performance, tone, multiton, and partial-band interference...
Any attempt to create multiple independent soundfields in separate zones over an extended region of open space results in unintended interference in a given zones from other zones. In this paper, we design spatial band stop filters to suppress interzone interference in the regions of interests and pass the desired soundfields with no distortion. This is achieved by using the higher order spatial harmonics...
In MIMO multi-relay systems, close-loop precoding at relay nodes is not necessary if unicast modes are carried out. However, in unicast modes, the inter-stream interference at relay nodes may degrade the system capacity. In this paper, two unicast modes are proposed to reduce the negative impact of the residual interference. The first one suppresses the interference by applying orthogonal precoding...
In this paper, a new beamformer is proposed for coherent signal reception with the assumption that the directions-of-arrival (DOA's) of the uncorrelated interferers are available. Here, the composite vector of the coherent sources is first estimated based on the use of a transformation matrix to eliminate the uncorrelated interferers. Then the optimum beamforming is performed based on the estimated...
For the uplink transmission of an orthogonal frequency division multiple access (OFDMA) system, frequency synchronization is particularly challenging due to the presence of multiple Carrier Frequency Offsets (CFOs), which destroy the orthogonality among subcarriers and introduce massive multiuser interference (MUI) and inter-carrier interference (ICI). To prevent the consequent performance degradation,...
We introduce complete analytical characterization of the nonlinear interference that results when passing more than one high-order modulation carrier through the same nonlinear transponder HPA. Based on this analysis, a novel Volterra filter is proposed that models nonlinear intersymbol interference (ISI) and adjacent channel interference (ACI). Our focus is on adaptive algorithms so that the solutions...
Iterative signal processing has gained in popularity over the last decade as a way of reducing the effects of interference in a communication system. In previous work, the expectation maximization (EM) algorithm was used to estimate the parameters and data of colliding transmissions in a slow frequency-hopping spread-spectrum (FHSS) system using binary frequency-shift keying (BFSK). As in many FHSS...
As the wireless access technology evovles to wider and wider bandwidth, orthogonal frequency division multiplex (OFDM) becomes the fundamental technology component to provide efficient data transmission. However, compared to code division multiplex access (CDMA), OFDM has no capability to mitigate the intercell interference though it can provide orthogonality among the intracell users. To build a...
Cognitive radio is observed as a new approach, which could be cope with the spectral limitations. This approach is designed to detect whether a particular segment of the radio spectrum is currently in use and to jump into the temporarily unused spectrum rapidly without interfering with the transmissions of other users. CR is the promising radio technology which aims to detect and utilize the temporally...
This paper presents a systematic solution to enable the code division duplex (CDD) system that allows the uplink- and downlink channel to work on the same frequency at the same time but with different smart codes. CDD is considered to be most spectral efficient among all other duplex systems. However, in comparison with the frequency division duplex (FDD) system, a CDD mobile station (MS) receiver...
In consideration of the overcrowded spectrum resource, it is of great importance to study the combination of the cognitive radio (CR) and ultra wideband impulse radio (UWB-IR). In the cognitive UWB scene, the UWB pulse is supposed to constantly change its spectrum according to the state of the primary users to mitigate the potential interference to these vulnerable wireless systems. Meanwhile, the...
This paper proposes a novel semi-dynamic inter-cell interference coordination (ICIC) scheme for multi-cell OFDMA systems. The objective of the novel scheme is to strike a balance between ICI minimization and frequency reuse factor (FRF) maximization. Firstly, we divide cell-edge users into non-overlapping user groups based on users' geometry, and classify each group's available bandwidth, which includes...
In this paper, we present a new method to generate ultra-wide band (UWB) pulses that not only meet the power spectral constraint of Federal Communications Commission (FCC), but also easily mitigate the multiple narrow-band interferences (NBI) distributed in the UWB band, which is allocated from 3.1 GHz to 10.6 GHz. Especially, this method can be flexibly extended to suppress any wide-band interference...
The combined contour control strategy of H_inf velocity feedback control, zero phase error tracking control (ZPETC) and normal cross-coupled control is proposed. It reduces the influences of load interference, mechanical time delay and parameter mismatch between two axes on the contour accuracy of XY table directly driven by two permanent magnet linear synchronous motors (PMLSM). E_inf velocity feedback...
This paper proposes a high capacity carrier interferometry/multicarrier code division multiple access (CI/MCCDMA)system through the simultaneous support of high and low data rate transmission. High data rate users transmit data through all sub-carriers while alternate odd and even subcarriers are shared by the low data rate users.The usage of alternate sub-carriers suggests to split CI codes in odd...
In this paper we put forward a scheme for suppressing narrowband interference by the use of adaptive narrowband filtering. We compare this method with other schemes for the suppression of complex narrowband interference in OFDM UWB systems, such as the frequency excision method and complex narrowband interference identification and cancelation algorithms. The study shows that the three schemes give...
Coordinating transmission techniques by multiple base stations or radio access points have recently attracted a lot of attention because of its potential for inter-cell co-channel interference mitigation and spectral efficiency significant improvement. This paper explicitly presents network multi-point coordinating downlink transmission technologies, especially discusses the clustered supercell configuration...
Due to advantages in enough number of channels and favorable bandwidth, 2.4 GHz ISM band is used as the most prevalent band for the IEEE802.15.4 LR-WPAN. However, there are an increasing number of other devices and systems which may interfere with the IEEE 802.15.4 communication. Therefore, the coexistence issue is one of the most critical challenges for the IEEE 802.15.4. In this paper, we propose...
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.