Implementation of wideband digital beam forming in the E-band

This paper reports the test results of a small-scale prototype that implements a digitally beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71â€"76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Wideband frequency-domain angle-of-arrival estimation and beam-forming algorithms were developed and implemented using Orthogonal Frequency Division Multiplexing (OFDM) with Quadrature Phase-Shift Keying (QPSK) at 1 Gbps. Measured performance is very close to the simulated results and experimental data for an analogue-beam-formed array. This work is a stepping stone toward practical realization of larger hybrid arrays in the E-band. © 2011 Cambridge University Press and the European Microwave Association

Massive hybrid antenna array for millimeter-wave cellular communications

© 2002-2012 IEEE. A massive hybrid array consists of multiple analog subarrays, with each subarray having its digital processing chain. It offers the potential advantage of balancing cost and performance for massive arrays and therefore serves as an attractive solution for future millimeter-wave (mm- Wave) cellular communications. On one hand, using beamforming analog subarrays such as phased arrays, the hybrid configuration can effectively collect or distribute signal energy in sparse mm-Wave channels. On the other hand, multiple digital chains in the configuration provide multiplexing capability and more beamforming flexibility to the system. In this article, we discuss several important issues and the state-of-the-art development for mm-Wave hybrid arrays, such as channel modeling, capacity characterization, applications of various smart antenna techniques for single-user and multiuser communications, and practical hardware design. We investigate how the hybrid array architecture and special mm-Wave channel property can be exploited to design suboptimal but practical massive antenna array schemes. We also compare two main types of hybrid arrays, interleaved and localized arrays, and recommend that the localized array is a better option in terms of overall performance and hardware feasibility

Multi-Gigabit Wireless Link Development

CSIRO ICT Centre is developing millimetre wave point-to-point links suitable for multi-gigabit wireless connectivity. Suitable spectrum for this purpose is allocated at the 60 GHz band and above. This paper reports a new point-to-point link that will be installed at Marsfield site to demonstrate multi-gigabit operation and performance of its key components. The link will operate at the 81-86 GHz band incorporating CSIRO designed millimetre wave MMICs and multi-gigabit modems

A hybrid adaptive antenna array for long-range mm-wave communications

Owing to the availability of wide (GHz) bandwidth at mm-wave frequencies, there is growing interest in high-speed mm-wave communications systems. However, the limited physical size and volume of the antenna and RF system do pose several major challenges. This article presents CSIRO's research on hybrid adaptive antenna arrays and associated digital-beamforming algorithms for achieving high-speed long-range communications in the millimeter-wave frequency bands. The hybrid antenna array consists of a number of analog subarrays, followed by a digital beamformer. Two subarray configurations - the interleaved subarray and the side-by-side subarray - are described. The adaptive angle-of-arrival (AoA) estimation and beamforming algorithms in both the time and frequency domains are discussed. The performance of the system was evaluated by simulations. An early stage proof-of-concept adaptive antenna array prototype in the 71 to 76 GHz E band is presented. © 2011 IEEE

Multi-gigabit wireless backhauls for broadband networks

With the emergence of next generation broadband wireless access and mobile systems, huge demands are being placed on the backhaul infrastructure. As cost-effective alternatives to traditional copper and fibre backhauls, high speed and long range wireless backhauls become more and more attractive. However, current existing wireless backhaul systems neither provide sufficiently high speed nor meet the requirements to achieve both high speed and long range at the same time. Multi-gigabit data rates can be obtained using millimetre-wave (mmwave) point-to-point systems, but the practical transmission range is still the major weakness. Traditional microwave systems can achieve longer transmission range, but the data rates are limited to a few hundred Mega bits per second only. In this article, a review on the demand for multi-gigabit wireless backhauls is given and the benefits of wireless backhauls are described. The radio propagation characteristics in both mm-wave and microwave frequency bands are provided to show the difference in transmission range for wireless backhauls in the two different bands. The state-of-the-art mm-wave and microwave technologies currently being developed at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) are introduced to illustrate CSIRO's technology leadership in high speed and long range broadband wireless backhaul systems. It is hoped that the article will stimulate further research interest and industry development

A multi-gigabit microwave backhaul

The rapid growth of multimedia broadband wireless services has placed huge pressure on the backhaul infrastructure. As cost-effective alternatives to fibre backhauls, high speed microwave backhauls provide a number of significant benefits, especially for bringing broadband services to rural and regional areas. This article addresses the challenges to wireless backhauls and presents a multi-gigabit microwave backhaul system, called Ngara backhaul, which is being developed at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia. The various innovative aspects of the Ngara backhaul system including spectrum aggregation, peak-toaverage power ratio reduction, out-of-band emission cancellation, and sample rate conversion, are reported. © 2012 IEEE