| 摘要 |
In LTE TDD with CA, a two bit sequence number or downlink assignment indicator (DAI) can be attached to downlink control information (DCI) messages relating to packets transmitted on some or all of successive carrier frequencies in a given subframe. The sequence number is incremented or decremented for each DCI transmitted depending on whether the total number of DCI message transmitted in a given subframe is even or odd. This allows detection of the loss of any three successive DCI (not including the last DCI). The loss of the last DCI in the sequence can also be detected without adding any more bits. This allows a more accurate and reliable common understanding between the transmitter and receiver concerning the number of DCI messages transmitted. This is useful, for example, if the format of transmission of ACK/NACK information relating to the DCI messages depends on the number of messages transmitted, since the most likely cases of failed detection of a DCI message can be detected and corrected. |
