A rigorous theoretical method for predicting "ratio of desired signal power to interference power [c/i]" and "ratio of signal power to noise plus interference power [c/(n+i)]" where both desired and interference signals vary with time under the Nakagami-Rice fading conditions is presented. An alternative simple prediction method which is more desirable from the viewpoint of engineering application is then proposed. Prediction errors given by the simple method are evaluated by comparing to the errors given by the rigorous method, and it is confirmed that the simple method gives reasonable accuracy. This method is expected to serve in the development of frequency re-use technologies and the coordination of various systems for mobile satellite communications in the near future.

We propose parallel rate-variable punctured convolutional coded PPM in photon communication to achieve high energy information efficiency Ie for desired bit error rate (BER) and transmission bandwidth. We theoretically show the BER performance, bandwidth expansion factor β and necessary Ie to achieve BER10-6 of the proposed systems for some combinations of code rates. It is found that the proposed system can achieve high Ie for desired BER and β by selecting a suitable combination of code rates depending on the channel conditions. Moreover, it is showm that the proposed system has better BER performance than RS-coded PPM in the range of small β.