When planning the communications between the rover and the base station the same parameters must be considered as when planning the link from the earth to the moon. That being said, the difference in those factors has a tremendous impact on the link budget and consequences thereof and results in a completely different link design.
| Link Parameters | ||
| Carrier Frequency | u: 915 MHz |
d:918 MHz |
| Bandwidth | u: 13 MHz | d: 13 MHz |
| Distance | 1000 m | |
| Beamwidth: | Isotropic | |
| Required SNR: | u:18 dB | d: 18 db |
| Antenna Gain | u: 2.15dBi | d: 2.15dBi |
| Power | u: -17.9dBm | d:-17.8dBm |
Unlike the link between the moon and the earth, the antennas used to propagate and receive the signal for this link will both be half-wave dipoles with 2.15 dBi (well defined value). In fact, the only parameter with a significant difference between the uplink and downlink is the carrier frequency. Since the freespace path loss increases with an increase in frequency, the downlink (from rover to moon station) has been given the lower frequency in an attempt to minimize the power needed by the rover. The following equation is used to solve for the necessary transmit power for each the uplink and downlink:
Based on the modulation scheme, only -104.28 dBm of needs to be recieved. After applying all of the parameters to the link, -17.9dBm of transmit power will allow for proper data transmission between the rover and the moon base station.
