This project considers the challenges in maximizing the worst-user’s rate for a multiple access Gaussian vector channel under power constraints. The multiple access Gaussian vector channel is derived from a multi-user OFDM uplink channel, which has no interference between subchannels. The optimal rate is determined at the maximal equal rate among the users. For a simple treatment, a multi-user ...

In this work, we consider the joint precoding across K transmitters (TXs), sharing the knowledge of the user’s data symbols to be transmitted towards K single-antenna receivers (RXs). We consider a distributed channel state information (DCSI) configuration where each TX has its own local estimate of the overall multiuser MIMO channel. The focus of this work is on the optimization of the allocat...

The paper makes a brief introduction of Multiple CarrierCode Division Multiple Access (MC-CDMA) scheme based on the principles of Orthogonal Frequency Division Multiplexing (OFDM) and CDMA, and a mathematical model of the uplink is established in MC-CDMA system. The simulation research on different multi-user detection methods in MC-CDMA system is implemented by using MATLAB software, and it al...

Mobile radio communication systems are affected by the frequency and time selectivity of radio channel due to multipath propagation and Doppler shifts. In an Orthogonal Frequency Division Multiplexing (OFDM) based Code Division Multiple Access (CDMA) system, the spreading schemes will suffer loss of orthogonality between codewords of different users. In this thesis, basic system model of severa...

Very few technologies have shown as much impact on the trajectory of evolution of wireless communication systems as multiple input multiple output (MIMO) systems. MIMO systems have already been employed in the existing 802.11n and 802.16e standards resulting in a huge leap in their achievable rates. A relatively recent idea of extending the benefits of MIMO systems to multi-user scenarios seems...

In this paper, low complexity rate and power optimization schemes operating in the spatial frequency domains are proposed a cognitive radio (CR) setting involving multi-user multiple-input-multiple-output-orthogonal division multiplexing (MU-MIMO-OFDM). Under assumption of perfect secondary channel state information (CSI) at receiver, presented architectures encompass two main stages. first one...

In this paper, the performance of multiuser MIMO ESDM systems in downlink transmission is evaluated in both uncorrelated and correlated time-varying fading environments. In the ideal case, using the block diagonalization scheme, inter-user interference can be completely eliminated at each user; and using the E-SDM technique for each user, optimal resource allocation can be achieved, and spatial...

Wireless multi-user MIMO communications are used more and more often to exchange sensitive data. Because of the broadcast nature of the physical medium, unauthorized receivers located within the transmission range can observe the signals sent by the transmitter to a legitimate receiver and eavesdrop them. Therefore, security has become an extremely important issue to deal with. Multiuser MIMO c...

In this paper, we develop a new distributed adaptive power control framework for multi-cell OFDM systems based on the game theory. A specific utility function is defined considering the users’ achieved average utility per power, i.e., power unit based utility. We solve the subcarrier allocation issue naturally as well as the power control. Each user tries to maximize its utility by adjusting th...