Årbok 2013

The spectrum was assigned when the servi::::es was introduced, QIVIng the best band

available at that time, without the knowledge of what would come later. There is also a

difference in radio range between frequency bands, the lower frequency bands providing

longer range and cheaper technology and this should also be considered.

Since there are for example many TV's and TV transmitters, it is very expensive to carry out

the frequency revolution needed to reassign the frequencies according to justified public

needs. lf we started all over again today, it is reasonable to assume that more bandwidth had

been given to radio services providing high speed Internet, since Internet could be used by

many services, li!<e

TV,

broadcast radio, mobile services etc.

To provide enough bandwidth to many, the high power transmitters covering a long range,

must be replaced by many small ones. This is similar to the problem of discussing with many

in a crowded room rather than splitting up the group in many small groups whispering with

each other. To reach the ultimate capacity, Illere is one radio base station for everyone and

the base station is connected by fibre to Internet. The single user base station is called a

femtocell and our portable devices will just whisper. From a radiation hazard point of view it

will be less hazardous.

These small base stations will be installed by ordinary people in large numbers without

careful radio-planning ensuring that they do not interfere with each other. Therefore they

must be self-organizing. This is mostly done by radios of the same type listening for

transmission from each other and in this way identifying all the transmitters in the

neighbourhood. When a receiver which may be disturbed is close, it cannot be discovered in

this way and neither can a radio using a different transmission format. A wireless microphone

system is for example not compatible with a mobile radio.

To solve this problem, the use of a national database has been proposed. Before anyone

may transmit, the availability of a free band must be checked using the database. There also

exists a complementary solution since many radios are already connected by wire to

Internet, based upon agents located inside all radios communicating with each other through

the backbone network. This peer to peer distributed technology does not require a database

and will scale betler as the amount of users increases. It can also be introduced in a network

without new infrastructure. In this solution. messages are sent between the agents who will

continuously search for new radios and then adapt power and frequency to maximize the

joint capacity of the network.

This solution has been simulated and is in the process of being tested in a trial network. It

shows that it is possible to up to double the amount of traffic it the radios behave in an

emphatic manner and make an effort in not disturbing each other.

The Norwegian Post and Telecommunications Authority has just announced the possibility

!hat in future frequency allocations the primary user need to share the band with secondary

users. The award of frequencies will be deci.ded by auctions. Even if the presence of

secondary users may not disturb the primary users, the operator of the primary user may not

be Willing to pay so much for the frequency allocations. Since the purpose of the auction is to

ensure that the frequencies are used, this is not a problem and this will pave the way for

empathic radio or "cognitive radio" as it is calied for the benefit of the society at large.