The use of interleaving for reducing radio loss in trellis-coded modulation systems

It is demonstrated how the use of interleaving/deinterleaving in trellis-coded modulation (TCM) systems can reduce the signal-to-noise ratio loss due to imperfect carrier demodulation references. Both the discrete carrier (phase-locked loop) and suppressed carrier (Costas loop) cases are considered and the differences between the two are clearly demonstrated by numerical results. These results are of great importance for future communication links to the Deep Space Network (DSN), especially from high Earth orbiters, which may be bandwidth limited

Multiple Trellis Coded Modulation (MTCM): An MSAT-X report

Conventional trellis coding outputs one channel symbol per trellis branch. The notion of multiple trellis coding is introduced wherein more than one channel symbol per trellis branch is transmitted. It is shown that the combination of multiple trellis coding with M-ary modulation yields a performance gain with symmetric signal set comparable to that previously achieved only with signal constellation asymmetry. The advantage of multiple trellis coding over the conventional trellis coded asymmetric modulation technique is that the potential for code catastrophe associated with the latter has been eliminated with no additional cost in complexity (as measured by the number of states in the trellis diagram)

Combined trellis coding and feedforward processing for MSS applications

The idea of using a multiple (more than two) symbol observation interval to improve error probability performance is applied to differential detection of trellis coded MPSK over a mobile satellite (fading) channel. Results are obtained via computer simulation. It is shown that only a slight increase (e.g., one symbol) in the length of the observation interval will provide a significant improvement in bit error probability performance both in AWGN and fading environments

Proposing a national ethical framework for animal research in Iran

Background: One of the domains of scientific activities is working on animals. Performing experiments on animals is permissible only with the purpose of obtaining necessary information for saving and improving life of human beings or animals. Principally, all religions believe that human life is more valuable than animal life and humans have a God-given authority over animals, but they should not be cruel to animals and cause their pain or suffering. Based on Islamic view points, although Allah has put the Man as the lord of all creatures, he has not the right to use other creatures for any conditions and does not respect their real statues. Because of the widespread use of experimental animals in our country, special ethical codes should be redefined for living conditions of experimental animals based on the present regulations in Iran and also other countries. Therefore, all our researchers should have enough information about ethical codes of treating experimental animals as well as Islamic principles in this regard.Methods: All Islamic and international sources related to treating animals and also valid international ethical guidelines were collected and classified in order to extract the aimed points. Then all extracted points were reviewed by experts familiar with Islamic and ethical rules of treating animals.Results: Finally the strategies for appropriate and complete implementation of the national ethical guidelines of animal research in Iran were suggested.Conclusion: It is obvious that the suggested principles are applicable only with appropriate planning of training courses based on the facilities and needs of our country