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Chapter 3The DVB/DAVIC protocol pThe backoff parameter is first initialised with an initial backoff exponent (also termed as‘Minimum Backoff Exponent’). This parameter is updated according to the receptionindicator received from transmission. The truncated backoff parameter (also referred toas ‘Maximum Backoff Exponent’) is the maximum allowable backoff. If a collisionoccurs, the backoff value is incremented by one. Once the backoff value reaches themaximum number determined by the truncated backoff, the backoff remains at thisvalue regardless of the number of subsequent collisions. After every successfultransmission, the backoff value is reset to the initial backoff value. The values of initialand truncated backoff are sent by the INA to the stations at the beginning of theconnection and remain the same until the NIUs stop the connection with the INA. Thesetwo values are equal for all the NIUs as opposed to the backoff value that is different ateach station.3.5.3 Splitting tree algorithm overviewAs defined in Appendix B.2, minislots are only used to transmit reservation requestwhen this algorithm is used. After an NIU sends a reservation request in a contentionbasedminislot, it waits for feedback information from the INA. In the case of collision,the NIU enters the contention resolution cycle and activates its resolution state.3-9