Multi Gigabit Millimetre Wave Wireless
As technology users continue to demand ever increasing speeds and ever faster untethered communications, the ICT Centres Wireless Technologies Laboratory are developing new technologies for high speed wireless connectivity.
CSIRO is utilising the millimetre-wave spectrum at 60 GHz and above, which makes data speeds of 10 Gigabit-per-second (Gbps) or more possible. This technology is at least 100 times faster than current Wireless Local Area Networks (WLANs). Gigabit wireless networks can be used to complement high speed fibre connections, in infrastructure for mobile communications, and for ad hoc communications services.
What are millimetre waves?
A 1 Giga-bit-per-second (Gbps) wireless link can:>
Time taken to transfer various items over a dedicated link using the listed standards:
Radio spectrum is a finite natural resource under increasing demand. We are using the emerging millimetre-wave spectrum at 60 GHz and above because this spectrum is not yet congested by users and it creates an opportunity of 100 times improvement in data rates compared to microwave systems such as wireless local area networks (WLANs). Other advantages of millimetre-wave communications include:
Antennas are smaller, portable and can have higher gain
Increased frequency reuse and security due to the narrow communication beam and limited radio range.
Wideband components are easier
Uncluttered wideband millimetre wave spectrum.
Multi-gigabit data-rate millimetre wave Networks are becoming viable due to the spectrum allocation and cost reduction in semiconductor devices.
The 60 GHz band has been allocated in many countries as free spectrum. Owing to the higher propagation loss caused by oxygen absorption, 60 GHz systems are more suited for indoor and short range applications. The recently allocated 71-76 and 81-86 GHz bands provide opportunity for links with longer range and higher data rates, ideally suited for fibre replacement and the backhauls of mobile communications networks. Current commercial products deliver data rates up to 1.25 Gbps, and new products up to 10 Gbps have been promised for the future.
In December 2006, CSIRO ICT Centre researchers have developed an all electronic 6 Gbps millimetre wave point-to point link in the 85 GHz band using 8 PSK (phase shift keying) modulation and achieving 2.4 bit/s/Hz spectral efficiency. This is the highest spectral efficiency to date for a millimetre wave system. The system can be easily upgraded to achieve 12Gbps or more if full 5 GHz bandwidth of the allocated commercial bands, 71-76 GHz or 81-86 GHz, is used.
The core technologies in the CSIRO multi-gigabit system include innovative architecture, world class MMICs for the radio transceivers, and novel modulation schemes and digital signal processing algorithms.
To help with outdoor testing of new link demonstrators and with propagation modelling at 60 GHz and above, a test bed has been installed at CSIRO in Marsfield, NSW. The testbed is 250m long, 10m above the ground and 95m above sea level. It includes a commercial 60 GHz link and two CSIRO-developed links in the 81-86 GHz band.
1 60 GHz commercial link
We are now researching new methods for adhoc long distance millimetre communication between moving nodes. CSIRO researchers with different background (in millimetre wave techniques, antennas and digital signal processing) are working closely together to create solutions for the future. Current research interests include: