Applications of the PAM Representation of CPM.
These performance gains come at the expense of complexity, and the proposed 2-state detectors minimize this expense. The second version of CPM studied in this work is Pulse Code Modulation/Frequency Modulation (PCM/FM).
By:
Category:
Language:enPublished on 2008 by ProQuest
In this thesis, we are trying to optimize the tradeoff between the receiver complexity and its performance for two modulations currently used in aeronautical telemetry. A reduced complexity detector is of interest because it reduces the implementation cost. The Pulse Amplitude Modulation (PAM) representation of Continuous Phase Modulation (CPM) signals typically results in reduced-complexity detectors with a performance that matches the performance of the optimal detector. In this work, we study simple trellis-based PAM detectors for two types of CPM used in aeronautical telemetry. The first is shaped-offset quadrature phase shift keying (SOQPSK), where we show that the state complexity can be cut in half relative to previous approaches---from 4 states down to 2---with asymptotically optimum performance. For comparison, we implement another reduced complexity technique known as Pulse Truncation (PT); both of these techniques make use of recent advances in SOQPSK technology based on a CPM interpretation of SOQPSK. The proposed simplifications are significant since trellis-based SOQPSK detectors are 1--2 dB superior with respect to the widely-deployed symbol-by-symbol detectors. These performance gains come at the expense of complexity, and the proposed 2-state detectors minimize this expense. The second version of CPM studied in this work is Pulse Code Modulation/Frequency Modulation (PCM/FM). We develop and compare the performances of 0, 2 and 4 state PAM based detectors. We develop our PCM/FM receiver using two approaches; first with a square-root cosine (SRC) filter which is independent of the CPM modulation index, and the second using the main PAM pulse followed by a whitening filter. The 4-state trellis based detectors we derive for PCM/FM give a performance within 0.4--0.5 dB of the optimal detector (refer to Appendix I for optimal detector complexity).
Preview link: http://books.google.com/books?id=kcaJMLjyzVMC&printsec=frontcover&dq=cpm&hl=&cd=25&source=gbs_api
This Book was ranked 25 by Google Books for keyword cpm.
0 Response to "Applications of the PAM Representation of CPM."
Posting Komentar