{'fraction_non_alphanumeric': 0.028500619578686492, 'fraction_numerical': 0.012391573729863693, 'mean_word_length': 5.516129032258065, '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}}
Exploiting frequency diversity in SDM/STBC multicarrier systems

The combination of spatial division multiplexing (SDM) and space-time block coding (STBC) is able to yield high-throughput and robust wireless communications (e.g. IEEE 802.11n). In the most common configuration, known as double space time transmit diversity (DSTTD), two Alamouti encoded streams are transmitted in parallel. In this paper we introduce an improved multicarrier hybrid STBC/SDM scheme whereby the transmitted symbols are spread onto different subcarriers. A computationally efficient and near optimal receiver architecture is presented which is able to exploit the additional diversity. Simulations results using the IEEE 802.11n framework configured to operate in DSTTD mode demonstrate the performance gains of our approach.