Characterization of Coded Random Access with Compressive Sensing based Multi-User Detection

The emergence of Machine-to-Machine (M2M) communication requires new Medium Access Control (MAC) schemes and physical (PHY) layer concepts to support a massive number of access requests. The concept of coded random access, introduced recently, greatly outperforms other random access methods and is inherently capable to take advantage of the capture effect from the PHY layer. Furthermore, at the PHY layer, compressive sensing based multi-user detection (CS-MUD) is a novel technique that exploits sparsity in multi-user detection to achieve a joint activity and data detection. In this paper, we combine coded random access with CS-MUD on the PHY layer and show very promising results for the resulting protocol.Comment: Submitted to Globecom 201

Towards Massive Connectivity Support for Scalable mMTC Communications in 5G networks

The fifth generation of cellular communication systems is foreseen to enable a multitude of new applications and use cases with very different requirements. A new 5G multiservice air interface needs to enhance broadband performance as well as provide new levels of reliability, latency and supported number of users. In this paper we focus on the massive Machine Type Communications (mMTC) service within a multi-service air interface. Specifically, we present an overview of different physical and medium access techniques to address the problem of a massive number of access attempts in mMTC and discuss the protocol performance of these solutions in a common evaluation framework

One-Pot Process That Efficiently Generates Single Stereoisomers of 1,3-Bisphosphinylpropanes Having Five Chiral Centers

<i>P,C</i>-Stereogenic 1,3-bisphosphinylpropanes <b>3</b> that have up to five stereogenic centers could be obtained stereoselectively in high yields by a one-step reaction of (<i>R</i>_P)-menthylphenylphosphine oxide <b>1</b> with α,β-unsaturated aldehydes <b>2</b> catalyzed by KOH at room temperature. A mechanism was proposed as to involve a stereoselective intermolecular 1,3′-phosphorus migration from the 1,2-adduct of <b>1</b> with <b>2</b> to another <b>2</b> generating a 1,4-adduct that subsequently reacts with <b>1</b> to produce <b>3</b>