{"id":361,"date":"2010-03-24T19:54:52","date_gmt":"2010-03-24T19:54:52","guid":{"rendered":"http:\/\/ravtrack.com\/GPStracking\/?p=361"},"modified":"2019-10-25T14:47:01","modified_gmt":"2019-10-25T21:47:01","slug":"tdma-transmission-overview","status":"publish","type":"post","link":"https:\/\/www.raveon.com\/data_radio_info\/tdma-transmission-overview-361\/","title":{"rendered":"TDMA Transmission Overview"},"content":{"rendered":"

TDMA, or Time-Division-Multiple-Access<\/em> is a very effective way of allowing a lot of radios to share one radio channel.\u00a0 Used extensively in GSM cellular and APCO public-safety systems, TDMA excels at allowing quick and reliable access to radio channels.\u00a0 Raveon’s M7 series of GPS tracking radios <\/a>and all narrow-band GPS tracking radios <\/a>use TDMA to send GPS position information, status, and data. It allows 2-10 times more radios to share a radio channel than conventional carrier-sense methods.\u00a0 This allows 2-10 times more tracking radios on one channel, as compared to radios that do not have TDMA capability.<\/p>\n

The following diagram illustrates how it works.<\/p>\n

\"\"<\/a><\/p>\n

When a GPS tracking Data Radio modem <\/em>wants to report its position and status, it waits until its assigned time-slot, and then transmits its data.\u00a0 By default, TDMA time slot positions are assigned by unit-ID, so RV-M7 GX<\/em> with ID 1 uses the first slot, and ID 2 uses the second slot, and so on.<\/p>\n

A TDMA \u201cFrame<\/em>\u201d time is the time it takes all units to transmit once.\u00a0 This is configured with the TDMATIME xx <\/strong>command.\u00a0 The factory default is 10 seconds, so every 10 seconds, each RV-M7 GX <\/em>may transmit. \u00a0The TDMA frame must be set long enough for all units to transmit. \u00a0For example, if you have 50 RV-M7<\/em>s, and use 200mS TDMA slots, then the TDMATIME<\/strong> should be set to 10 seconds.\u00a0 The simplest way to set it the TDMATIME<\/strong> is to make it equal to the TXRATE<\/strong>, the rate you wish to report position<\/p>\n

The duration of a TDMA time slot is programmed into the RV-M7 GX<\/em> with the SLOTTIME<\/strong> command. If SLOTTIME<\/strong> is set to 200 milliseconds (factory default), then every 10 seconds, the RV-M7 will have a 200mS window to report its position in.<\/p>\n

All TDMA frames are synchronized automatically in all RV-M7 GX Transponders<\/em> to the top of the minute. \u00a0Slot 0, frame 0 is at the top of each minute. They use the internal GPS receiver to determine the current time, and calculate when their are supposed to transmit their position and status information.<\/p>\n

A unit may be allocated additional time slots.\u00a0 The SLOTQTY command sets the number of slots each unit receives.\u00a0 It is normally set to 1.<\/p>\n","protected":false},"excerpt":{"rendered":"

TDMA, or Time-Division-Multiple-Access is a very effective way of allowing a lot of radios to share one radio channel.\u00a0 Used extensively in GSM cellular and APCO public-safety systems, TDMA excels at allowing quick and reliable access to radio channels.\u00a0 Raveon’s M7 series of GPS tracking radios and all narrow-band GPS tracking radios use TDMA to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[],"_links":{"self":[{"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/posts\/361"}],"collection":[{"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/comments?post=361"}],"version-history":[{"count":3,"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/posts\/361\/revisions"}],"predecessor-version":[{"id":1271,"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/posts\/361\/revisions\/1271"}],"wp:attachment":[{"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/media?parent=361"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/categories?post=361"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.raveon.com\/data_radio_info\/wp-json\/wp\/v2\/tags?post=361"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}