Jörgen Karlsson

Worldwide trends in regulation of secondary access to white spaces using cognitive radio

We review the state of the art in worldwide regulation of cognitive radio-based secondary access to radio spectrum. Emerging regulatory trends with regards to incumbent protection and detection, operation parameters of cognitive radio, and secondary licensing models in the United States, United Kingdom, Europe, and elsewhere are reviewed and compared. Particular emphasis is given to cognitive radio operation in unused portions of TV bands, the so-called TV white spaces. Initial views on regulatory feasibility of secondary access to civilian radar and military bands are presented.

Feasibility evaluations for secondary LTE usage in 2.7–2.9GHz radar bands

In this paper, we have studied the potential for secondary usage of radar bands by 3GPP LTE eNB devices in different scenarios, such as HeNB transmitters located at street level, HeNB transmitters located at high-rise buildings, macro LTE transmitter, etc. Different pathloss models are used to best suite the scenarios. By using different types of radar characteristics (e.g. radio navigations radars, meteorological radars, etc) and a protection requirement of −10dB Interference-to-Noise Ratio (INR), we have shown that in some scenarios, the required distances for adjacent channel radar usage in 2.7–2.9GHz band are quite reasonable. This means, in those scenarios, it could be possible to utilize the radar bands for secondary LTE systems. A protection margin of 18 to 20dB can be added for capturing the aggregate interference effects from multiple secondary interferers for downlink direction. More detailed system level investigations are required in this direction for further understanding the secondary usage in this band.

Spectrum requirements for TV broadcast services using cellular transmitters

Wide-spread provisioning of TV services has strongly shaped the cultural development since the last century; terrestrial radio broadcast transmission has been the original form of TV distribution. Although the majority of TV reception is today based on alternative distribution means, like cable or satellite, TV broadcast enjoys still a significant amount of allocated terrestrial spectrum (∼300 MHz). However, it has been identified that TV broadcast does not efficiently use its allocated spectrum. At the same time, other spectrum users like mobile communication systems experience a tremendous growth and demand for spectrum. The scarcity of radio spectrum has led the US FCC rule that additional 500 MHz of spectrum are to be identified for mobile broadband systems in the next decade — out of which 120 MHz are to come from the TV band in the next 5 years. In this paper we identify an alternative transmission architecture for TV distribution based on cellular LTE MBMS, with densely placed low-power transmitters that transmit in a synchronized single frequency network. It is demonstrated that in this way a full frequency reuse at all sites is possible, in contrast to the large reuse distances in high-power high-tower TV transmission. As a result, we show that it is possible to support TV services with 84 MHz of spectrum via LTE MBMS, in contrast to the 300 MHz used by todays ATSC TV broadcast system. This approach can be realized in a cost-effective manner by re-using existing mobile network infrastructure and we also show that the total radiated power can be decreased.