CSi in South Africa: Examining CSI Strategy, Practice, and Attitudes with a Focus on Social Enterprise and Blended Value

The project aimed to: Identify attitudes and practices among leading CSI officers in South Africa surrounding CSI objectives, CSI strategy, and major philanthropy models, particularly social enterprise and blended valueAssess the market for Heart's Blended Value Proposition Funds among CSI officer

Dynamic Power Splitting Policies for AF Relay Networks with Wireless Energy Harvesting

Wireless energy harvesting (WEH) provides an exciting way to supply energy for relay nodes to forward information for the source-destination pairs. In this paper, we investigate the problem on how the relay node dynamically adjusts the power splitting ratio of information transmission (IT) and energy harvesting (EH) in order to achieve the optimal outage performance. According to the knowledge of channel state information (CSI) at the relay, optimal dynamic power splitting policy with full CSI and partial CSI are both provided. Finally, through simulations, the proposed power splitting policies can improve the outage performances and the policy with full CSI achieves the best performance. It is also shown that the policy with partial CSI can approach the policy with full CSI closely and incurs far less system overhead.Comment: accepted by IEEE ICC 2015 - Workshop on Green Communications and Networks with Energy Harvesting, Smart Grids, and Renewable Energie

Regularized ZF in Cooperative Broadcast Channels under Distributed CSIT: A Large System Analysis

Obtaining accurate Channel State Information (CSI) at the transmitters (TX) is critical to many cooperation schemes such as Network MIMO, Interference Alignment etc. Practical CSI feedback and limited backhaul-based sharing inevitably creates degradations of CSI which are specific to each TX, giving rise to a distributed form of CSI. In the Distributed CSI (D-CSI) broadcast channel setting, the various TXs design elements of the precoder based on their individual estimates of the global multiuser channel matrix, which intuitively degrades performance when compared with the commonly used centralized CSI assumption. This paper tackles this challenging scenario and presents a first analysis of the rate performance for the distributed CSI multi-TX broadcast channel setting, in the large number of antenna regime. Using Random Matrix Theory (RMT) tools, we derive deterministic equivalents of the Signal to Interference plus Noise Ratio (SINR) for the popular regularized Zero-Forcing (ZF) precoder, allowing to unveil the price of distributedness for such cooperation methods.Comment: Extended version of an ISIT 2015 submission. Addition of the proofs omitted due to space constrain

Overhead-Aware Distributed CSI Selection in the MIMO Interference Channel

We consider a MIMO interference channel in which the transmitters and receivers operate in frequency-division duplex mode. In this setting, interference management through coordinated transceiver design necessitates channel state information at the transmitters (CSI-T). The acquisition of CSI-T is done through feedback from the receivers, which entitles a loss in degrees of freedom, due to training and feedback. This loss increases with the amount of CSI-T. In this work, after formulating an overhead model for CSI acquisition at the transmitters, we propose a distributed mechanism to find for each transmitter a subset of the complete CSI, which is used to perform interference management. The mechanism is based on many-to-many stable matching. We prove the existence of a stable matching and exploit an algorithm to reach it. Simulation results show performance improvement compared to full and minimal CSI-T.Comment: 5 pages, 2 figures. to appear at EUSIPCO 2015, Special Session on Algorithms for Distributed Coordination and Learnin

The CSI Effect: Fact or Fiction?

The CSI effect has been a subject undergoing intense scrutiny in recent years. With the ever-increasing number of television shows, such as CSI and all of its spinoffs, that poorly represent the field of forensic science, there has also been a growing concern over the effects that media has on the legal system. Prosecutors argue that the CSI effect raises their burden of proof and makes jurors more likely to acquit in cases involving little or no forensic evidence, while defense lawyers claim that jurors are more inclined to wrongfully convict based on their unrealistic perceptions of forensic evidence. This paper aims to determine if the CSI effect exists by exploring the effects that crime-show-related media has on the community, analyzing jurors’ perceptions of forensic evidence, and comparing the currently published statistics on pre- and post-CSI acquittal rates

CSI Feedback Reduction for MIMO Interference Alignment

Interference alignment (IA) is a linear precoding strategy that can achieve optimal capacity scaling at high SNR in interference networks. Most of the existing IA designs require full channel state information (CSI) at the transmitters, which induces a huge CSI signaling cost. Hence it is desirable to improve the feedback efficiency for IA and in this paper, we propose a novel IA scheme with a significantly reduced CSI feedback. To quantify the CSI feedback cost, we introduce a novel metric, namely the feedback dimension. This metric serves as a first-order measurement of CSI feedback overhead. Due to the partial CSI feedback constraint, conventional IA schemes can not be applied and hence, we develop a novel IA precoder / decorrelator design and establish new IA feasibility conditions. Via dynamic feedback profile design, the proposed IA scheme can also achieve a flexible tradeoff between the degree of freedom (DoF) requirements for data streams, the antenna resources and the CSI feedback cost. We show by analysis and simulations that the proposed scheme achieves substantial reductions of CSI feedback overhead under the same DoF requirement in MIMO interference networks.Comment: 30 pages, 7 figures, accepted for publication by IEEE transactions on signal processing in June, 201