09-05-2014, 02:19 PM
Ultra Wide Band (UWB) and Short-Range Devices (SRD) technologies
New trends in radiocommunications
Typical frequency management faces new challenges in relation with :
New radiocommunication technologies (Ultra Wide Band, software radio, cognitive radio,….)
The need for increased bandwidth and mobility for civil telecommunications applications
The willingness from number of radio administrations to facilitate the spectrum access (so-called “flexibility”), including rapid access to the spectrum
All these trends are currently presenting a high potential of risk for many “public” frequency users, among of which the meteorological community
What are Ultra Wide Band (UWB)
All present the same characteristics:
Large Bandwidth from 500 kHz up to 5 GHz,
Low power or e.i.r.p. density levels
Potential fo high density deployment
Hence extend over large frequency ranges (mainly between 1 and 10.6 GHz) potentially impacting a variety of radiocommunication services
The interference scenarios
All interference scenarios are possible depending on:
UWB characteristics and operational modes
“Victim” applications characeristics
Single entry case, i.e. interference produced by one single UWB devices
Aggregate case, i.e. interference produced by a number of UWB devices simultaneously transmitting
Interferers at short distances (few km) from terrestrial stations
Regulatory implications
For terrestrial applications (radars, METSAT receiving stations,…), the interferers are at short distances, hence limited to domestic rules (free circulation is however an issue)
For satellites uplink (as well as for Radio Astronomy), the interference case extend over international rules
UWB devices do not present potential impact for receiving satellites (active)
This is the case for satellite passive sensing that hence represents an international issue :
interference from UWB in one country may interfere the satellite passive sensors of another country
Global measurements that benefit to all WMO members may be polluted
Some UWB devices (SRR, GPR/WPR,…) intend to transmit in bands covered by Radio Regulations Footnote 5.340 that states that “all emissions are prohibited”
UWB and SRD Threats
The aggregate interference from multiple equipments is usually the dominant scenario (assessment of number of equipment is not a trivial issue)
This is of particular concerns for EESS passive sensors
for this case, the aggregate effect of emissions from SRDs deployed within one country can also have negative impact on space-based radiocommunication systems operated by other administrations
National decisions : difficult for WMO to survey all countries policies (important role of national NMHS)
Free circulation : risk of multiple non compliant equipments
unlicensed and mass-market leading to “point of no-return” : if not adequately regulated or if initial sharing assumptions are not correct,
uncontrolled deployment of a very large number of “interfering” SRD or UWB, impossible to manage by NRA, i.e. a de facto pre-emption of the band
Loss of a band for the whole meteorological community (even if limited to one single country) with obvious operational and financial consequences
Don’t hesitate to get in contact with WMO SG-RFC on these issues