{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-8509291","patent":{"patent_number":"US-8509291","title":"Open-loop transmit diversity schemes with four transmit antennas","assignee":null,"inventors":[],"filing_date":"2009-02-04T00:00:00.000Z","publication_date":"2013-08-13T00:00:00.000Z","cpc_codes":["H04B","H04B","H04B","H04L","H04L"],"num_claims":51,"abstract":"In a wireless communication system, SFBC-based (Space-Frequency Block-Code) transmission diversity schemes provide enhancement for multiple antennas, such as the illustrative four, in order to achieve better performance than SFBC-FSTD (SFBC-Frequency Switching Transmit Diversity) alone. SFBC-PFSTD (Precoded Frequency Switching Transmit), which is multiplying a precoding matrix to the SFBC-FSTD signals, opens up the possibility of utilizing the pilot tones in synchronization channels (SSC and/or PSC) to enhance the channel estimation performance for antenna 2 and 3 that have only the half as many pilot tones as antenna 0 and 1. Further improvements are disclosed for use of Frequency Time Switching Transmit Diversity (FTSTD) and Precoding Vector Switch."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"Open-loop transmit diversity schemes with four transmit antennas","description":"In a wireless communication system, SFBC-based (Space-Frequency Block-Code) transmission diversity schemes provide enhancement for multiple antennas, such as the illustrative four, in order to achieve","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-8509291","license":"CC-BY-4.0-like","license_terms":"AI-generated analysis on this page (summary, layman_explanation, technical_analysis, business_analysis, faqs) may be reused with attribution and a visible link back to the canonical URL above. Patent abstracts, claims, and bibliographic data are USPTO public domain.","required_link":"https://patentable.app/patents/US-8509291","citation_suggestion":"Patentable. \"Open-loop transmit diversity schemes with four transmit antennas\" (US-8509291). https://patentable.app/patents/US-8509291","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-8509291","json":"https://patentable.app/api/llm-context/US-8509291","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-05-30T18:14:56.398Z"}