{'fraction_non_alphanumeric': 0.009216589861751152, 'fraction_numerical': 0.0, 'mean_word_length': 5.437037037037037, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Universal space-time trellis codes

The compound channel theorem for linear Gaussian vector channels indicates that a single code can provide reliable communication on all channels that induce a minimum amount of mutual information. This paper discusses the search for space-time trellis codes that deliver such consistently good performance on every matrix channel that has a proximity to channel capacity similar to standard trellis codes in AWGN. By characterizing the minimum distance of an error event transformed by the channel as a function of the eigenvalues of the channel matrix, we search for codes having the largest such worst-case distance for systems with two transmit antennas. Proposed trellis codes found by exhaustive search guarantee coded performance on every matrix channel without sacrificing error performance under quasistatic Rayleigh fading.