A method for allocating a time-frequency transmission slot to a terminal in a Low Earth Orbit, LEO, satellite communication system, the LEO satellite communication system comprising a plurality of terminals and a common receiver in a LEO satellite for receiving transmissions from the plurality of terminals wherein the terminals can control their transmit frequency, the common receiver having a field of view, the method comprising: obtaining a geographic position of the terminal; and allocating a time-frequency transmission slot based upon the obtained geographic position of the terminal, wherein there is no feedback channel from the common receiver to the plurality of terminals or a feedback channel from the common receiver to the plurality of terminals is present but is not being used for allocation of a time-frequency transmission slot and allocation of a time-frequency transmission slot to the terminal is performed independently of the common receiver or other terminals and exploits the frequency diversity resulting from the LEO induced Doppler shifts in signals transmitted to the satellite by either obtaining a probability density function q * for the transmission frequencies used by the terminals and allocation of slots to terminals is performed using q * such that, after the effect of Doppler, the common receiver in the LEO satellite sees an approximately uniform distribution of frequencies over the frequency band, or by selecting a slot from a slot plan database that exploits Doppler induced frequency reuse where each terminal includes the slot plan database which comprises a plurality of geographic regions, and each geographic region is associated with a set of one or more slots wherein the same set of slots are used for both a first region and a second region, and the first and second regions (144, 143) correspond to different regions in a common field of view (3, 141) of the common receiver, the first region having positive Doppler offsets and the second region having negative Doppler offsets, and allocating a time-frequency transmission slot comprises the steps of: determining the geographic region that contains the geographic position of the terminal; and selecting a slot from the set of one or more slots associated with the determined geographic region. obtaining a geographic position of the terminal; and allocating a time-frequency transmission slot based upon the obtained geographic position of the terminal, wherein there is no feedback channel from the common receiver to the plurality of terminals or a feedback channel from the common receiver to the plurality of terminals is present but is not being used for allocation of a time-frequency transmission slot and allocation of a time-frequency transmission slot to the terminal is performed independently of the common receiver or other terminals and exploits the frequency diversity resulting from the LEO induced Doppler shifts in signals transmitted to the satellite by either obtaining a probability density function q * for the transmission frequencies used by the terminals and allocation of slots to terminals is performed using q * such that, after the effect of Doppler, the common receiver in the LEO satellite sees an approximately uniform distribution of frequencies over the frequency band, or by selecting a slot from a slot plan database that exploits Doppler induced frequency reuse where each terminal includes the slot plan database which comprises a plurality of geographic regions, and each geographic region is associated with a set of one or more slots wherein the same set of slots are used for both a first region and a second region, and the first and second regions (144, 143) correspond to different regions in a common field of view (3, 141) of the common receiver, the first region having positive Doppler offsets and the second region having negative Doppler offsets, and allocating a time-frequency transmission slot comprises the steps of: determining the geographic region that contains the geographic position of the terminal; and selecting a slot from the set of one or more slots associated with the determined geographic region. determining the geographic region that contains the geographic position of the terminal; and selecting a slot from the set of one or more slots associated with the determined geographic region.