New forms of WiMAX coming out of CRC

Canada's Communications Research Centre is meeting demand for new variations of the WiMAX standard as interest in the broadband wireless technology picks up steam around the world. Speaking at the Future of WiMAX in Canada conference last week, Gerry Chan, VP of terrestrial wireless at the CRC, says there is tremendous opportunity for WiMAX in the future as a result of new research.During his 45-minute presentation, he highlighted several key WiMAX research areas in which the CRC is involved including very high-speed mobile data rates, cognitive radio as well as 700 MHz white space devices. The CRC operates a WiMAX 3.5 GHz test bed in Ottawa where it conducts propagation and interference studies and develops design guidelines for future WiMAX systems. The research lab is also migrating its system to the 2.5 GHz band to conduct further testing WiMAX systems.Currently the test network consists of three base stations located at the CRC's campus in Ottawa's west end, working with 16 customer premise equipment (CPE). The CPE and network gear are from a variety of vendors, including Axxcelera, Wavesat, Vecima, Airspan and Redline. This allows the CRC to conduct interoperability testing with the goal of enabling equipment vendors and service providers to deploy systems that will perform at optimum levels.Mobile WiMAXIn October 2007, the International Telecommunication Union decided to add the mobile WiMAX standard to the global IMT-2000 standard for mobile systems. This was a "major achievement", according to Chan, noting that this was the sixth standard to become part of the IMT-2000 family and the first added in the last 10 years.The impact of this has yet to be noticeably felt because mobile WiMAX deployments around the world are still in their infancy with few operators having deployed mobile WiMAX systems. But in the future, mobile WiMAX could have a significant impact because it can operate in all of the bands designated for IMT-2000 and it is now considered equal with the other mobile standards.As well, research is currently being done to give mobile WiMAX the same types of bandwidth capabilities as the next-generation mobile systems. Work on the 802.16m standard - the advanced version of mobile WiMAX - is underday to attain data rates of 100 Mbps to 1 Gbps. "This is pretty well in the same order to magnitude as LTE and 4G", giving the standard the same type of capacity as the other mobile standards, said Chan.White spacesWith the US Federal Communications Commission's decision to approve the use of white spaces devices - low-power, short-range wireless connectivity operating in the TV bands - there is still great concern that co-channel interference will have a harmful effect on broadcasting services. The CRC is vice-chair of the Institute of Electrical and Electronics Engineers (IEEE) working group studying this matter under the proposed 802.22 standard.Because these systems share the same frequencies as TV channel spectrum, the need to avoid co-channel interference is critical, said Chan. He pointed to spectrum sensing, signal classification, geolocation of terminals and dynamic frequency selection as some of the techniques under development. These capabilities would allow the device to sense its environment and then react so as to not cause any interference into broadcast services.Cognitive radioDespite mobile WiMAX being accepted in the IMT-2000 family of mobile standards, there are still some challenges associated with deploying a mobile network based on this technology. Notably, mobile WiMAX networks have to co-exist with other fixed WiMAX systems and non-WiMAX systems and this is where research in cognitive radio will be able to help, said Chan. The work is being done under the 802.16h standard."Cognitive radio is the capability for the radio to sense its environment and it has the intelligence to know what the environment is and to be able to adapt itself to that environment so as to minimize interference," he explained.When fully integrated into the mobile WiMAX standard, networks will be able to sense that they are sharing the same frequency space with other systems and then react according. These cognitive radio capabilities will improve the co-existence of WiMAX systems in the same bands.

New forms of WiMAX coming out of CRC

News | November 14, 2008

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