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In modern cellular systems, high-rate communication is performed using MIMO transmission by a single base station (BS). This method is able to improve the transmission rate when the user is at the cell-inner. However the rate severely degrades when the user is located at cell-edge. Base station cooperation (BSC) MIMO is solve the cell-edge problem. BSC MIMO can improve capacity at the cell-edge than...
A space-time coding scheme based on interleave division multiplexing (EDM) is investigated over an orthogonal frequency division multiplexing (OFDM) link that employs multiple transmit antennas. The performance of an iterative receiver structure for the proposed scheme over a quasi-static channel is evaluated via simulation, and its advantages are shown by comparison to other space-time schemes in...
Diversity-multiplexing tradeoff (DMT) of asymmetric two-user full-duplex cooperative multiple-access (CMA) channels with multiple-antenna terminals is studied. The channel is asymmetric in the sense that the users are not restricted to have the same multiplexing and diversity gains. Using the network capacity cut-set bound, we first derive the DMT upper bounds of a general K-user CMA channel. Following...
The following topics are dealt with: neural networks; equalisation; mobile and cellular communications; optical communications; data security; human factors in communications; coding and modulation; optical networks; database and optimisation; time-frequency analysis; computer vision and recognition; audio and speech processing; wireless networks; watermarking; digital filters; network coding and...
Ultra wideband (UWB) technology is one of the promising solutions for future short-range communication which has recently received a great attention by many researchers. However, interest in UWB devices prior to 2001 was primarily limited to radar systems, mainly for military applications, due to bandwidth resources becoming increasingly scarce and also its interference with other commutation networks...
The combined block diagonalization and geometric mean decomposition (BD-GMD) is a preceding scheme that is asymptotically optimal for downlink multi-user multiple-input-multiple-output (MU-MIMO) systems. The number of simultaneously supportable users with BD-GMD is limited by the number of transmitting and receiving antennas. In a downlink MU-MIMO system with a large number of users, the base station...
A high peak-to-average power ratio (PAPR) is one of the serious disadvantages of an orthogonal frequency-division multiplexing (OFDM) system. Therefore, many PAPR reduction methods have been introduced. Especially, the signal scrambling methods such as selective mapping (SLM), partial transmit sequences (PTS), and polyphase interleaving and inversion (PII) are the attractive methods for obtaining...
The uplink capacity evaluation of cellular multiple input multiple output (MIMO) system is of great interest but not straight forward. This paper presents a framework to evaluate the uplink cellular capacity. In this framework, the effects of co-channel interference (CCI) as well as the effects of transmit power control (TPC) have been taken into consideration. The uplink capacities assuming various...
Cooperative communication usually shares a common model-one source, several relays and one destination. In this paper, we consider the multi-source scenario in a cell to carry on cooperative communication. However, multi-user setting might causes interference in the network, given this interference, the process of relaying selection applies SINR (signal to interference noise ratio) as a criterion...
We consider a multiple-access multiple-input-multiple-output (MIMO) system with minimum mean square error successive interference cancellation (MMSE-SIC) receiver. Spatial multiplexing is employed with some of the users having target-rate requirements while other users are working with best-effort data rates. We show that the best-effort users can achieve higher rates when the data streams of any...
A multi-lattice-reduction aided (MLRA) vector precoding algorithm is proposed in this paper. Compared with traditional lattice-reduction-aided (LRA) method, the new method tries to find a set of candidates of perturbation vectors through reducing the formulated lattice to get subspaces of searching space. Within each subspace, a candidate vector is solved. Then the optimum vector is found in this...
Observation of the mobile satellite system industry shows a significant growth in the need for more demanding services and higher rates these last years; as an example, recent success of hybrid broadcasting system (XM, Sirius) and DVB-SH arrival are meeting commercial users expectations in terms of high rates mobile communications. In this context, the use of diversity and MIMO schemes (cyclic delay...
This paper studies the use of amplify-and-forward (AF) relays for robust beamforming, with the aid of imperfect channel state information (CSI) at the sender. In particular, the maximization of the worst-case signal-to-noise ratio (SNR) at the destination terminal is studied under a bounded spherical region for the norm of CSI error vector. We show that under a condition on the estimated CSI quality,...
To overcome the adverse effects of wireless channel, cooperative communications is the practical implementation of Multiple-Input-Multiple-Output (MIMO) concept in size constraint nodes. To exploit the benefits of cooperative transmission properly, we use the block-Markov encoding. Recently, an operational implementation of this information theoretic coding strategy, using network coding, has been...
Subblock Successive Transform (SST) algorithm is an effective method to reduce the PAPR of the MIMO-OFDM signals, and can fully utilize the degrees of freedom in space domain to overcome the shortage of Successive Suboptimal Cross-Antenna Rotation and Inversion (SS-CARI) algorithm. However, the degrees of freedom in frequency domain are not considered in SST algorithm. For this problem, an improved...
Compared with other multi carrier modulate systems, MIMO-OFDM also adopting this kind of technique, is prone to produce high peak-to-average power ratio (PAPR), which will result in frequency spectrum spread and in-band distortion enormously due to the nonlinearity of the high power amplifier. To this main fault in MIMO-OFDM, many scholars propose some new idea to overcome it. Based on SLM technique,...
We address the problem of designing coset codes for use over slow block fading MIMO channels. We consider as inner code different codes built over cyclic algebras (in particular for different number of antennas), and show that two alternative approaches for the outer code are either codes on cyclic algebras over finite fields, or error correcting codes over finite fields.
We examine the extent to which Gaussian relay networks can be approximated by deterministic networks, and present two results, one negative and one positive. The gap between the capacities of a Gaussian relay network and a corresponding linear deterministic network can be unbounded. The key reasons are that the linear deterministic model fails to capture the phase of received signals, and there is...
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