Method for determining parameters for the design of ground equipment for a satellite link system and a method of transmitting signals in a satellite link system

Claim 3

The method of claim 1, including the steps of checking that the minimum transponder power falls within the non-uplink power control region and if so selecting parameters for the design of the ground equipment which do not require uplink power control facility.

Claim 4

The method of claim 1, wherein if the minimum transponder power requirement does fall within the uplink power control region a minimum amount of uplink power control can be utilized to provide the required availability or an increase in transponder power can be utilized.

Claim 5

The method of claim 1, wherein if the point of minimum transponder power does not fall in a range where no uplink power control is required, the method includes a technique of iteration whereby new site degradation parameters are selected until a point of minimum transponder power for those parameters is determined which falls within the range where no uplink power control is required.

Claim 6

The method of claim 1, wherein the step of determining the range where no uplink power control is required comprises the steps of: determining a first uplink rain attenuation function relating rain attenuation to the percentage of time for which this rain attenuation is exceeded at a first ground site; determining a second uplink rain attenuation function relating rain attenuation to the percentage of time for which this rain attenuation is exceeded at a second ground site; determining a first downlink rain degradation function relating rain degradation to the percentage of time for which this rain degradation is exceeded at the first ground site; determining a second downlink rain degradation function relating rain degradation to the percentage of time for which this rain degradation is exceeded at the second site; calculating the first and second uplink rain attenuation functions and calculating the first and second downlink rain degradation functions against outage time for the first and second sites with the second uplink attenuation function and second downlink degradation function having their Y axes drawn at a predetermined outage time of the first uplink attenuation function and first downlink degradation function and with the X scale inverted so that the predetermined outage time of the second uplink attenuation function and second downlink degradation function occur at zero availability for the first uplink attenuation function and first downlink degradation function; and determining where the first uplink rain attenuation function intersects the second downlink rain degradation function to define a first point and determining where the second uplink rain attenuation function intersects the first downlink rain degradation function to define a second point; uplink power control being required at the first site if the outage time at the first site is less than that at the first point and uplink power control is not required at the second site if the outage time allocated at the first site is less than that of the second point; if the first point occurs at an outage time at the first site which is less than the outage time at the first site for the second point then uplink power control is not needed at either site for outage times at the first site between the two points; and if the first point occurs at an outage time at the first site which is greater than the outage time at the first site for the second point then uplink power control is needed at both sites for outage times at the first site between the two points.

Claim 7

The method of claim 1, wherein the system operates in any band subject to rain attenuation.

Claim 8

The method of claim 1, wherein the range where no uplink power control is required is calculated as follows: a. solve TPD'(x1)=0 to obtain x 1m which is minimum Transponder power point, b. solve f ru1 (x1)=f rd2 (x2) to obtain x 1L which is lower limit of non uplink power control, c. solve f rd1 (x1)=f ru2 (x2) to obtain x 1u which is upper limit of non uplink power control, d. if x 1L ≦x 1m ≦x 1u is true, then configure links using x 1m as the operating point, e. if x 1L >x 1m , then configured links using x 1L as the operating point, f. if x 1u <x 1m , then configure links using x 1u as the operating point, g. if condition in e or f exist, then antenna gains can be increased at either end, h. if x 1u ≦x 1L then configure links using x 1m as the operating point and use the difference between f rd1 (x1) and f ru2 (x2) to determine the amount of uplink power control required at the first site and likewise the difference between f ru1 (x1) and f ru2 (x2) to determine the amount of uplink power control at the second site.

Claim 11

The method of claim 8, further comprising the steps of checking whether the minimum transponder power falls within the non-uplink power control region and, if so, transmitting the signals without uplink power control.

Claim 12

The method of claim 8, wherein if the minimum transponder power requirement does fall within the uplink power control region a minimum amount of uplink power control can be utilized to provide the required availability or an increase in transponder power can be utilized.

Claim 13

The method of claim 8, wherein if the point of minimum transponder power does not fall in a range where no uplink power control is required, the method includes a technique of iteration whereby new site degradation parameters are selected until a point of minimum transponder power for those parameters is determined which falls within the range where no uplink power control is required.

Claim 14

The method of claim 8, wherein the step of determining a range where no uplink power control is required comprises the steps of: determining a first uplink rain attenuation function relating rain degradation to the percentage of time for which this rain degradation is exceeded at a first ground site; determining a second uplink rain attenuation function relating rain attenuation to the percentage of time for which this rain attenuation is exceeded at a second ground site; determining a first downlink rain degradation function relating rain attenuation to the percentage of time for which this rain attenuation is exceeded at the first ground site; determining a second downlink rain degradation function relating rain degradation to the percentage of time for which this rain degradation is exceeded at the second site; calculating the first and second uplink rain attenuation functions and calculating the first and second downlink rain degradation functions against outage time for the first and second sites with the second uplink attenuation function and the second downlink degradation function having their Y axes drawn at a predetermined outage time of the first uplink attenuation function and first downlink degradation function and with the X scale inverted so that the predetermined outage time of the second uplink attenuation function and second downlink degradation function occur at zero availability for the first uplink attenuation function and first downlink degradation function; and determining where the first uplink rain attenuation function intersects the second downlink rain degradation function to define a first point and determining where the second uplink rain attenuation function intersects the first downlink rain degradation function to define a second point; uplink power control being required at the first site if the outage time at the first site is less than that at the first point and uplink power control is not required at the second site if the outage time allocated at the first site is less than that of the second point; if the first point occurs at an outage time at the first site which is less than the outage time at the first site for the second point then uplink power control is not needed at either site for outage times at the first site between the two points; and if the first point occurs at an outage time at the first site which is greater than the outage time at the first site for the second point then uplink power control is needed at both sites for outage times at the first site between the two points.

Claim 15

The method of claim 8, wherein the system operates in any band subject to rain attenuation.

Claim 16

The method of claim 8, wherein the range where no uplink power control is required is calculated by performing the following steps: a. solving TPD' (x1)=0 to obtain x 1m which is the minimum transponder power point; b. solving f ru1 (x1)=f rd2 (x2) to obtain x 1L which is a lower limit of non-uplink power control; c. solving f rd1 (x1)=f ru2 (x2) to obtain x 1u which is an upper limit of non-uplink power control; d. if x 1L ≦x 1m ≦x 1n is true, then configuring links using x 1m as the operating point; e. if x 1L >x 1m , is true, then configuring links using x 1L as the operating point; f. if x 1u <x 1m , is true, then configuring links using x 1u as the operating point; g. if conditions determined in e or f exist, then increasing antenna gains at either end; h. if x 1u ≦x 1L is true, then configuring links using x 1m as the operating point and using the difference between f rd1 (x1) and f ru3 (x2) to determine the amount of uplink power control required at the first site and likewise the difference between f ru1 (x1) and f rd2 (x2) to determine the amount of uplink power control at the second site.