When an antenna array is used to focus a transmitted signal on a receiver, we call this beamforming (or precoding) and we usually illustrate it as shown to the right. This cartoonish illustration is only applicable when the antennas are gathered in a compact array and there is a line-of-sight channel to the receiver. If we want … Continue reading Beamforming From Distributed Arrays
Three massive-MIMO-related highlights from IEEE ICC in Kansas City, MO, USA, this week: J. H. Thompson from Qualcomm gave a keynote on 5G, relaying several important insights. He stressed the fundamental role of Massive MIMO, utilizing reciprocity (which in turn, of course, implies TDD). This is a message we have been preaching for years now, … Continue reading Three Highlights from ICC 2018
Five most read posts How Much does Massive MIMO Improve the Spectral Efficiency? Channel Hardening Makes Fading Channels Behave as Deterministic Six Differences Between Massive MIMO for Sub-6 GHz and mmWave What is the Difference Between Beamforming and Precoding? Six Differences Between MU-MIMO and Massive MIMO Popular posts from 2017 Pilot Contamination in a Nutshell … Continue reading Popular Posts
I attended GLOBECOM in Singapore earlier this week. Since more and more preprints are posted online before conferences, one of the unique features of conferences is to meet other researchers and attend the invited talks and interactive panel discussions. This year I attended the panel “Massive MIMO – Challenges on the Path to Deployment”, which was … Continue reading Challenges on the Path to Deployment
The channel between a single-antenna user and an -antenna base station can be represented by an -dimensional channel vector. The canonical channel model in the Massive MIMO literature is independent and identically distributed (i.i.d.) Rayleigh fading, in which the vector is a circularly symmetric complex Gaussian random variable with a scaled identity matrix as correlation/covariance matrix: … Continue reading What is Spatial Channel Correlation?