April 26, 2017

Cell-Edge-Aware Precoding for Downlink Massive MIMO Cellular Networks

  • Andrews J.
  • Geraci G.
  • Quek T.
  • Yang H.

We propose a cell-edge-aware (CEA) zero forcing (ZF) precoder that exploits the excess spatial degrees of freedom provided by a large number of base station (BS) antennas to suppress inter-cell interference at the most vulnerable user equipments (UEs). We evaluate the downlink performance of CEA-ZF, as well as that of a conventional cell-edge-unaware (CEU) ZF precoder in a network with random base station topology. Our analysis and simulations show that the proposed CEA-ZF precoder outperforms CEU-ZF precoding in terms of (i) aggregate per-cell data rate, (ii) coverage probability, and (iii) 95%-likely, or edge user, rate. In particular, when both perfect channel state information and a large number of antennas N are available at the BSs, we demonstrate that the outage probabilities under CEA-ZF and CEU-ZF decay as 1/N2 and 1/N, respectively. This result identifies CEA-ZF as a more effective precoding scheme for massive MIMO cellular networks. Our framework also reveals the importance of scheduling the optimal number of UEs per BS, and confirms the necessity to control the amount of pilot contamination received during the channel estimation phase.

View Original Article

Recent Publications

May 22, 2017

Multidimensional Resource Allocation in NFV Cloud

  • Goldstein M.
  • Raz D.
  • Segall I.

Network Function Virtualization (NFV) is a new networking paradigm in which network functionality is implemented on top of virtual infrastructure deployed over COTS servers. One of the main motivations for the shift of telco operators into this paradigm is cost reduction, thus the efficient use of resources is an important ...

May 20, 2017

The Actual Cost of Software Switching for NFV Chaining

  • Caggiani Luizelli M.
  • Raz D.
  • Saar Y.
  • Yallouz J.

Network Function Virtualization (NFV) is a novel paradigm allowing flexible and scalable implementation of network services on cloud infrastructure. An important enabler for the NFV paradigm is software switching, which needs to satisfy rigid network requirements such as high throughput and low latency. Despite recent research activities in the field ...

May 08, 2017

Coexistence-aware dynamic channel allocation for 3.5 GHz shared spectrum systems

The paradigm of shared spectrum allows secondary devices to opportunistically access spectrum bands underutilized by primary owners. As the first step, the FCC targeted sharing the 3.5 GHz (3550–3700 MHz) federal spectrum with commercial systems. The proposed rules require a Spectrum Access System to implement a three-tiered spectrum management framework, ...