نتایج جستجو برای: multi user ofdm
تعداد نتایج: 687104 فیلتر نتایج به سال:
This paper provides intermediate transceiver and frame structure concepts and corresponding results for the European FP7 research project 5GNOW. The Unified Frame Structure concept is presented which supports an integrated 5G air interface, capable of dealing both with broadband data services and small packet services within the same band. Waveforms which tolerate higher levels of robustness, e...
The next generation wireless communications systems require higher data rates transmission in order to meet the higher demand of quality services. Research in wireless digital communications techniques have been expending very rapidly in the last few decades, resulting more reliable wireless communication systems that operate at higher spectral efficiency. Since there have been an increased in ...
The effect of two different pilot-assisted channel estimation techniques on BER in Multi-Carrier CDMA (MCCDMA) is considered. The first technique involves sending both data and pilot symbols in the same OFDM symbol. The second technique involves sending data and pilot symbols in separate OFDM symbols. In both cases multi-access interference is present. Simulations of both systems in a UMTS mult...
Braided convolutional codes (BCCs) form a class of iteratively decodable convolutional codes that are constructed from component convolutional codes. In braided code division multiple access (BCDMA), these very efficient error correcting codes are combined with a multiple access method and inherent interleaving for channel diversity exploitation into one single scheme. In this paper, we describ...
The energy efficiency has become more important in MIMO wireless communication system in recent days. The antennas at each end of the communications circuit are combined to minimize errors and optimize data speed. In Multiple Input Multiple Output Time Division Duplexing (MIMO TDD), by assuming reciprocity property the downlink transmission is based on uplink channel estimation. When more uplin...
This thesis addresses optimization issues in dynamic multi-user OFDM systems. The investigations are focused on the down-link of a single wireless cell. Dynamic sub-carrier assignments to terminals are periodically generated by the access point based on channel predictions. Several issues are considered in this context. First, the thesis investigates optimal and suboptimal assignment strategies...
In this paper we show how a fundamental result from information theory can be used to calculate the aggregate channel capacity in the uplink of an access point or a base station. The fundamental limits for this cell capacity provide an upper bound for any practically implementable multiple-access scheme. The capacity loss due to various implementation constraints is evaluated and a method for a...
Wireless broadband communications for users moving at vehicular speed is a cornerstone of future fourth generation (4G) mobile communication systems. We investigate a multi-carrier (MC) code division multiple access (CDMA) system which is based on orthogonal frequency division multiplexing (OFDM). A spreading sequence is used in the frequency domain in order to distinguish individual users and ...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید