A LOW-COMPLEXITY PORT SELECTION AND POWER ALLOCATION SCHEME IN DISTRIBUTION MIMO SYSTEMS

Information theoretical results have shown that Distributed Antenna Systems (DAS) can obtain higher capacity than Co-located Antenna Systems (CAS). In this paper,we investigate a downlink port selection and power allocation scheme in Distributed Multiple-Input Multiple-Output (D-MIMO) systems,where Distributed Antenna (DA) ports randomly locate in the cell. The contri-bution of this paper can be summarized as two parts. Firstly,we analyze how antenna correlation af-fects power allocation in D-MIMO systems. Secondly,based on large scale fading and antenna corre-lation,a low-complexity port selection and power allocation scheme is proposed. In the proposed scheme,we take both large scale fading and antenna correlation into consideration. Moreover,User Equipment (UE) only needs to feedback the rank of transmit antenna correlation matrix,which will not increase system complexity too much. Simulation results verify the capacity improvement based on the proposed power allocation scheme.

An Evaluation of Abidjan Container Terminal Competitive Position in West Africa Using a Fuzzy Quantified SWOT Framework

This article proposes a quantified SWOT framework which integrates fuzzy linguistic preference relation to evaluate the competitive position of Abidjan container terminal in West Africa. The integration of fuzzy linguistic preference relation in the quantified SWOT framework circumvents the difficulties in terms of data collection and consistency of judgment matrices prevailing in the conventional AHP and Fuzzy AHP. Moreover, the study provides relevant evidences about the key internal and external attributes shipping lines considered as important and hence the attributes that ports/ terminals most need to enhance in order to improve their attractiveness and be well positioned in the market. On the other hand, the change in terminals competitive position between 2010 and 2013 highlights that the difficulties of West African ports in attracting customers in the sub-region are not only related to internal problems such as inadequate infrastructures, facilities or inefficiency, but significant political and economic constraint outside the ports constraints their competitiveness.

Resource allocation in downlink OFDMA distributed multipoint systems with incoherent and coherent transmitters

Distributed multipoint systems （DMS） are important and timely for the move to future broadband wireless communication systems. Traditional studies on DMS have mainly focused on the issues with the spatial division multiple access such as precoding techniques, which only consider a narrowband case. This paper addresses the downlink radio resource management of the orthogonal frequency division multiple access DMS （OFDMA-DMS）, including power allocation between users or subcarriers, and distributed antenna selection. Signal models with incoherent and coherent transmitters are built. To maximize the system throughput, for the incoherent transmitter case, a strategy based on the iterative water-filling power allocation is proposed to approach the optimality. As for the coherent case, where coherent additions of the signal could occur at the users, the problem is transformed into an integer programming which is solvable. Numerical results show that the gain from the coherent transmitter is promising. And to achieve a near-optimal solution, only part of the DA ports will be used, which have better channel conditions.