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The LOS components of the base station (BS) can provide a high SNR to mobile stations (MSs), but they cannot achieve a high spatial multiplexing gain in the MIMO-OFDMA system. The spatial multiplexing gain is obtained by degrees of freedom between MIMO antenna arrays. MIMO channels should be uncorrelated to achieve the maximum degrees of freedom, and it depends on rich scattering environments which...
The mobile WiMAX standard (802.16e) uses multiple-input multiple-output (MIMO) limited feedback linear precoding to exploit the channel state information at the transmitter. Although the performance of limited feedback linear precoding in relation to traditional open-loop MIMO-OFDM has been extensively studied in the literature, these studies commonly assume perfect channel estimation at the receiver...
We propose a cross-layer strategy that jointly optimizes user scheduling and resource allocation for adaptive modulation and coding (AMC) based orthogonal frequency multiple access (OFDMA). The objective of this paper is to maximize the system throughput as a function of the bit error rate (BER) and the spectral efficiency based on selected modulation and coding schemes (MCSs). The proposed optimal...
In future wireless communication systems like LTE, wide bandwidths for the transmission of high data rates result in frequency selective mobile radio channels. If data transmission takes place at high mobile speeds the mobile radio channel becomes also time selective. In this paper we propose for the estimation of such double selective channels a modification to the well known complex exponential...
Inter-cell interference coordination (ICIC) is one of the key technologies in the multi-cell radio resource management of mobile systems. It plays a vital role in mitigating strong inter cell interference and guaranteeing proper quality of services for in-progress sessions. Because heterogeneous deployment is adopted in LTE-Advanced, and interference problem becomes serious. In this paper, we propose...
In this work, we analyze the performance of a multi-user sectored MIMO/OFDMA system under the limited feedback constraint. Dynamic radio resource management methods are used to a reuse-one sectorized cell in order to reduce the cross-sector interference. Simulation results show that the proposed strategy reduces the co-channel interference and maintain at the same time high spectral efficiency.
In mobile OFDM systems, such as underwater acoustic and digital video broadcasting (DVB) systems, time variation causes severe inter-carrier interference (ICI) which limits data detection performance. To address this problem, a signal processing strategy using several partial-interval FFTs instead of a conventional full-interval single FFT is proposed. Weighted combining of the partial FFT outputs...
Due to the increasing demand in mobile communications it is necessary to use the available spectrum as efficiently as possible. In this paper we focus on the concept of overlay scenarios where two different systems operate independently in the same frequency band. We describe a general set of characteristic parameters for licensed systems using FDMA (frequency division multiple access). In the context...
Pushed by international trends to develop intelligent transport systems, railways operators rely more and more on the new information and communication technology to optimize exploitation and maintenance costs but also to enhance the friendliness, comfort and security feeling of public transport by offering new services to passengers while traveling. There is not a lot of study dealing with the problem...
This paper introduces direct channel feedback in broadband multi-stream MIMO-OFDM communications as an efficient means for providing the base station with complete broadband channel information. The mobile station first estimates the complete (frequency selective) downlink channel responses between all transmit and receive antenna combinations and then transmits these responses back to the base in...
This paper analyzes the performance of selected mapping and partial transmit sequences in the multiinput multioutput orthogonal frequency division multiplexing (MIMO-OFDM) system using a space-time block code. The phase rotation vector, which is transmitted as side information, is considered. Simulation results show that the PAPR is decreased about 5 dB in the PTS, and about 3.5 dB in SLM, compared...
OFDM, MC-CDMA and DS-CDMA are being researched vigorously as the prospective signaling technique for the next generation mobile communications systems, which is characterized by the broadband packet technology. With packet transmission, hybrid ARQ (HARQ) is inevitable for error control. HARQ with rate compatible punctured turbo (RCPT) codes is one of the promising techniques. Data rate equivalent...
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