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.