Ulrika Engström

Non-Line-of-Sight Microwave Backhaul in Heterogeneous Networks

In this paper we present a study on the applicability and performance of microwave backhauling of small-cells in a heterogeneous network. Microwave backhaul in non-line-of-sight (NLOS) between a hub and a client provides a cost efficient and flexible small-cell deployment. In contrast to conventional NLOS communications using sub-6 GHz frequencies we propose the use of super-6 GHz frequencies which offers high antenna gain with reasonably sized antennas and wide bandwidths in licensed spectrum. We study both Point-to-Point (PtP) and Point-to-Multi-Point (PtMP) system concepts. The PtP system is characterized by pencil beam antennas with unshared radio resources for each link. The PtMP system is characterized by a single wide-beam antenna system at the hub with radio resources that are shared between multiple clients.

Multi-beam antennas in a PMP system: an up-link carrier to interference ratio performance evaluation

The performed study is an up-link carrier to interference (C/I) performance evaluation of narrow multibeam and wide sector-beam node antennas in a PMP system. It is shown that the introduction of three-beam node antennas improves up-link C/I with 5 dB compared with wide-beam sector antenna. The replacement of wide-beam antennas can be made on a sector by sector basis. Simulations have shown that it is possible to get significant interference improvement in a 5/spl times/3 hub network by replacing 20% of the wide-beam antennas with multi-beam antennas.

A 23 GHz sector antenna for point-to-multipoint communications

A broadband and compact antenna concept for a point-to-multipoint communication system at millimeter-wave frequencies is presented. The antenna consists of a rectangular feed waveguide, an H-plane parallel plate horn, an enclosed parabolic reflector section, a radiation slot aperture, and corrugated external baffles. The bandwidth is 2.9 GHz corresponding to a relative bandwidth of 12.6 % at 23 GHz for a return loss better than 10 dB of a prototype. The overall dimensions of the manufactured antenna are 200 mm by 147 mm by 50 mm