L29 - ITU Frequency Allocations for Space Systems Part II

Question 1

Explain the two methods by which orbital positions are managed by the ITU

Answer 1

• First come, first served o Rights secured through coordination process → registration in Master International Frequency Register (MIFR) o Perceived as unfair by developing countries b/c all their GEO slots could be taken
• A priori Frequency Planning o Rights secured through filing for an allotment in a satellite service plan and appendix 30B o Plans by World and Regional Planning Conferences
• Region 1 – Europe/Africa
• Region 2 – America • Region 3 – Asia • Each country has a specific # of channels
• Spectrum tends to be underutilized o Plans developed for broadcasting sat service and fixed sat service

Question 2

Explain the basic steps to accessing the orbit in the unplanned bands.

Answer 2

• Allocation – a given frequency band is assigned a purpose for use by one or more radio-communication services/radio astronomy service under specified conditions o One band = one service
• Allotment – a designated frequency channel in an agreed plan to be used by one or more administration for a terrestrial or space radio-communication service in one or more identified countries/areas
• Assignment – authorization given by administration for a radio station to use a radio frequency under specified conditions
• Must file at least 2 years before intended use, and no more than 7 o Enables time for coordination with potentially affected networks and resolution of issues
• Problem with speculation and “paper satellites” – discouraged by filing fees of 22,000CHF (one free filing per annum) for commercial-type slots o No/minimal fees for remote sensing and nanosats o More discipline in application process, requires users to be more serious
• Requires long term vision – must plan the satellite before you get the allocation b/c must file manufacture and launch information

Question 3

Explain how the ITU seeks to ensure equitable access to the orbit and spectrum.

Answer 3

• A priori frequency planning
• More involved application process discourages paper satellites and misuse of allocations
• Considering the question of a satellite monitoring system to help states resolve interference/occupancy issues

Question 4

Explain the two most common comsat services and allocations

Answer 4

• Fixed Satellite Service o Radio-communication bwn earth stations at given positions (specified fixed point or just fixed w/in specified area) when one or more satellites are used o C band – GEO FSS, good for equatorial regions, minimal rain attenuation
• Has some a priori frequencies for uplink and downlink o Ku Band, Ka band, V band (nothing here yet)
• Mobile Satellite Service o Radio-communication between mobile earth stations and one or more space stations OR between mobile earth stations via space stations o L, S, Ku bands o Inmarsat, Thuraya, Iridium, Globalstar