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A two-way relay channel (TWRC) in which two terminals <i>T</i> <sub>1</sub> and <i>T</i> <sub>2</sub> exchange orthogonal frequency division multiplexing (OFDM) signals with the help of an amplify-and-forward (AF) relay <i>T</i> <sub>3</sub> is considered here, and an efficient technique for allocating powers to <i>N</i> parallel tones of OFDM is developed.(More)
Presented in this paper is a study of the capacity evaluation of various multiuser MIMO schemes in cellular environments. The throughputs per user of the generalized zero-forcing with rank adaptation and vector perturbation schemes are compared with the capacity bound of the Gaussian MIMO broadcast channel, obtained by dirty paper coding under proportional(More)
—This paper considers a multiuser two-way relay channel (MU-TWRC) in which a base-station and a selected mobile-station (MS) among í µí°¾ number of MSs exchange messages during two time slots with the help of a half-duplex amplify-and-forward relay. We analyze the performances of a MU-TWRC. The closed-form expressions of the lower bound of the average rates(More)
This paper proposes a block diagonalization (BD) method, which nullifies the multiuser interference and, hence, increases the sum capacity in a multiuser multiple-input multiple-output (MU-MIMO) downlink system. The proposed BD scheme employs all users' receive processing as well as channel information. In addition, this paper proposes three adaptive mode(More)
Digital signage (DS) has become a phraseology for recent technology, is gaining massive acceptance to the technology-dependent world. Though the development of DS includes the essence of advertisement purposes, the fusion strategy makes it promising for communication technology. This paper demonstrates a Symbiotic Digital Signage (SDS) system in which one(More)
—This paper describes the design of a time-division duplexing frame with a variety of pilots for multiuser multiple-input–multiple-output orthogonal frequency-division multiple access (MU-MIMO OFDMA) systems, where the base station and users are equipped with four and two transmitting and receiving antennas, respectively. In addition, a simplified(More)
This correspondence considers a hybrid cognitive radio (H-CR) where the primary transmitter (PT) transmits message to the primary receiver (PR) whenever traffic occurs by allowing interference level <i>I</i> from the secondary transmitter (ST) to the PR, and the ST transmits messages to the secondary receiver (SR) by controlling the transmitting power based(More)
— We introduce a multiuser (MU) scheduling method for amplify-and-forward (AF) relay systems, which opportunis-tically selects both the transmission mode, i.e., either one-or two-hop transmission, and the desired user. A closed-form expression for the average achievable rates is derived under two transmissions with MU scheduling, and its asymptotic solution(More)
A limited feedback-based transmit beamforming technique for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) is investigated in time-varying channels. The performance of the system is significantly degraded by outdated feedback information even when the channel varies slowly. To compensate for the impairment in(More)