March 13, 2017

Reduced Switching Connectivity for Large Scale Antenna Selection

  • Garcia Rodriguez A.
  • Masouros C.
  • Rulikowski P.

In this paper, we explore reduced-connectivity radio frequency (RF) switching networks for reducing the analog hardware complexity and switching power losses in antenna selection (AS) systems. In particular, we analyze different hardware architectures for implementing the RF switching matrices required in AS designs with a reduced number of RF chains. We explicitly show that fully-flexible switching matrices, which facilitate the selection of any possible subset of antennas and attain the maximum theoretical sum rates of AS, present numerous drawbacks such as the introduction of significant insertion losses, particularly pronounced in massive multiple-input multiple-output (MIMO) systems. Since these disadvantages make fully-flexible switching suboptimal in the energy efficiency sense, we further consider partially-connected switching networks as an alternative switching architecture with reduced hardware complexity, which we characterize in this work. In this context, we also analyze the impact of reduced switching connectivity on the analog hardware and digital signal processing of AS schemes that rely on received signal power information. Overall, the analytical and simulation results shown in this paper demonstrate that partially-connected switching maximizes the energy efficiency of massive MIMO systems for a reduced number of RF chains, while fully-flexible switching offers sub-optimal energy efficiency benefits due to its significant switching power losses.

View Original Article

Recent Publications

March 23, 2017

Performance Comparison of Capacity-Achieving Modulation Formats for Transoceanic Optical Systems

  • Fernandez De Jauregui Ruiz I.
  • Ghazisaeidi A.
  • Tran P.

We experimentally compare the performance of geometrically-shaped (64APSK) and probabilistically-shaped 64QAM (PS64QAM) formats considering linear and nonlinear penalties.

March 20, 2017

LWIP and Wi-Fi Boost Link Management

  • K S.
  • Kim B.
  • Ling J.
  • Lopez-Perez D.
  • Ming Ding
  • Vasudevan S.

3GPP LWIP Release 13 technology and its prestandard version Wi-Fi Boost have recently emerged as an efficient LTE and Wi-Fi integration at the IP layer, allowing uplink on LTE and downlink on Wi-Fi. This solves all the contention problems of Wi-Fi and allows an optimum usage of the unlicensed band ...

March 13, 2017

Advanced C+L-Band Transoceanic Transmission Systems Based on Probabilistically-Shaped PDM-64QAM

  • Brindel P.
  • Buchali F.
  • Carbo Meseguer A.
  • Charlet G.
  • Fernandez I.
  • Ghazisaeidi A.
  • Hu Q.
  • Renaudier J.
  • Rios-Muller R.
  • Schmalen L.
  • Tran P.

We review the most recent, advanced concepts and methods employed in the cutting-edge spectrally-efficient coherent fiber-optic transoceanic transmission systems, such as probabilistic shaping, adaptive digital nonlinear compensation, rate-adaptive spatially-coupled low density parity check codes, and dual-band C+L-band transmission. Building upon all these concepts and methods, we demonstrate transmission of 179 ...