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 number of mobile subscribers has increased tremendously in recent years. The orthogonal frequency- division multiplexing (OFDM) system carries the message data on orthogonal subcarriers for parallel transmission, combating the distortion caused by the frequency selective channel or equivalently, the inter-symbol-interference in the multi-path fading channel. Carrier frequency offset (CFO) in OFDM...
Carrier frequency offset (CFO) is a major factor that degrades performance of the orthogonal frequency division multiplexing (OFDM) system. For orthogonal frequency division multiple access (OFDMA) uplink systems, there are multiple CFOs need to be estimated simultaneously, which is a very challenging task. Particle swarm optimization (PSO) algorithm has been recognized a potential approach for CFOs...
In future communications, cooperative communication with relay networks will be the one of the most effective scheme to enlarge coverage area and to boost data rate. In the recent research results, the path selection, power allocation and relay protocols on relay networks are the most important factors to improve the system performance. However, the channel quality of direct transmission path and...
In this paper, we propose a method that joints channel estimation and interference cancellation for direct-sequence ultra-wideband (DS-UWB) systems. For the channel estimation, we apply an expectation-maximization algorithm which adopts an iterative computation of maximum-likelihood parameter estimates, with a few number of iterations, the channel coefficient in each finger of Rake receiver can be...
In this paper, to compromise between the diversity gain and the multiple access interference (MAI), we propose a selection tree to choose a suitable combining scheme for 2-D spreading orthogonal frequency coded division multiplexing (OFCDM) communication system. Simulation results show that the proposed selection tree adaptive combining (STAC) scheme can not only suppress the MAIs induced by the non-orthogonality...
In multi-carrier code-division multiple-access (MC-CDMA) system the multiple access interference (MAI) is a critical factor that significantly degrades system performance. In this research the genetic algorithm (GA) is employed for joint channel estimation and multi-user detection. For improving exploration and exploitation strengths of GA, a GA-based approach called SAM-GA is developed by incorporating...
In this paper, we propose an adaptive particle swarm optimization (APSO) based partial parallel interference cancellation scheme for direct-sequence code-decision multiple access (CDMA) communication system over frequency selective fading channels. However, the partial cancellation tries to reduce the cancellation error in parallel interference cancellation schemes due to the wrong interference estimations...
This paper proposes that the Hopfield neural network (HNN) with hyperbolic tangent activation is introduced and applied to multiuser detection in direct sequence-ultra-wideband (DS-UWB) systems. It can approximate to maximum likelihood (ML) detector by mathematical analysis. The HNN with hyperbolic tangent activation (tanhHNN) can enhance the performance of HNN detector. According to the HNN technology,...
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.