{"id":2310,"date":"2025-12-13T09:06:12","date_gmt":"2025-12-13T08:06:12","guid":{"rendered":"https:\/\/localdab.org\/?page_id=2310"},"modified":"2025-12-13T09:06:50","modified_gmt":"2025-12-13T08:06:50","slug":"fic-bitrate","status":"publish","type":"page","link":"https:\/\/localdab.org\/index.php\/glossary\/e-h\/fic-bitrate\/","title":{"rendered":"FIC bitrate"},"content":{"rendered":"\n<p class=\"has-medium-font-size wp-block-paragraph\">Capacity calculation for the FIC payload<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">The <em><a href=\"https:\/\/localdab.org\/index.php\/glossary\/e-h\/fic-data\/\" data-type=\"page\" data-id=\"1814\" target=\"_blank\" rel=\"noreferrer noopener\">Fast Information Channel<\/a><\/em> (FIC) consists of three \u201cmodulation cycles\u201d or three \u201ctime slots,\u201d sometimes also referred to as symbols within the <em><a href=\"https:\/\/localdab.org\/index.php\/glossary\/q-t\/transmission-frame\/\" data-type=\"page\" data-id=\"1425\" target=\"_blank\" rel=\"noreferrer noopener\">transmission frame<\/a><\/em>.<br>These symbols are spread across the 1,536 carriers used in DAB Mode I.<br>This results in:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>3 \u00d7 2 bits \u00d7 1,536 = 9,216 bits<\/strong> per transmission frame of <strong>96 ms<\/strong>.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">Converted to a bitrate:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>9,216 bits \/ 0.096 s \u2248 96,000 bits per second (96 kbps).<\/strong><\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">This is the raw capacity available for the <em><a href=\"https:\/\/localdab.org\/index.php\/glossary\/e-h\/fic-data\/\" data-type=\"page\" data-id=\"1814\" target=\"_blank\" rel=\"noreferrer noopener\">FIC<\/a><\/em>.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">However, the transmitter applies <strong>forward error correction (FEC)<\/strong> using a 1\/3-rate convolutional code. As a result, the <strong>effective user data rate becomes 32 kbps<\/strong>.<\/p>\n\n\n\n<div style=\"height:31px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">From the Perspective of the ETI-LI Frame<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">Within the ETI-LI frame, <strong>96 bytes<\/strong> are allocated for the FIC payload in DAB Mode I (source: ETSI ETS 300 799).<br>The reasoning is as follows:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-small-font-size\"><strong>96 bytes = 768 bits<\/strong><\/li>\n\n\n\n<li class=\"has-small-font-size\"><strong>768 bits \/ 24 ms = 3072 bits per 96 ms = 32,000 bits\/s (32 kbps)<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">This calculation shows that the ETI-LI interface indeed transports <strong>32 kbps of actual FIC information<\/strong> from the multiplexer to the transmitter.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">At the transmitter side, <strong>FEC 1\/3 is applied<\/strong>, expanding the data so that the final transmission frame contains the full <strong>96 kbps FIC channel capacity<\/strong> over the air.<br>This approach uses strong FEC but <strong>omits time interleaving<\/strong>, ensuring the receiver obtains FIC information as quickly as possible.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">Another way to view this is through the FICL (FIC Length) parameter in the ETI-LI frame.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><br><strong>Conclusion:<\/strong><\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">For DAB Modes I, II, and IV, <strong>FICL = 24 words (bytes)<\/strong>.<br>In the FIC field, the structure defines <strong>FICL (bytes) \u00d7 4 = 96 bytes<\/strong>, consistent with the statements in other documents.<\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\"><em>Caution: Do not confuse the 24 words with the net FIC data capacity for ETI-LI. There is a factor-of-4 difference, as clearly stated in the description of the ETI-LI frame in the ETSI documents.<\/em><\/p>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\"><em><a href=\"https:\/\/localdab.org\/index.php\/glossary\/\" data-type=\"page\" data-id=\"15\">Back<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Capacity calculation for the FIC payload The Fast Information Channel (FIC) consists of three \u201cmodulation cycles\u201d or three \u201ctime slots,\u201d sometimes also referred to as symbols within the transmission frame.These symbols are spread across the 1,536 carriers used in DAB Mode I.This results in: 3 \u00d7 2 bits \u00d7 1,536 = 9,216 bits per transmission [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":1259,"menu_order":121,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2310","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2310","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/comments?post=2310"}],"version-history":[{"count":1,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2310\/revisions"}],"predecessor-version":[{"id":2311,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2310\/revisions\/2311"}],"up":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/1259"}],"wp:attachment":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/media?parent=2310"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}