Method and apparatus for transmitting and receiving downlink control signal in wireless communication system
摘要
說(shuō)明書
Referring to Table 1, a UE-specific search space supports an aggregation level {1, 2, 4, 8}, and in this example, has {6, 6, 2, 2} PDCCH candidates, respectively. A common search space supports an aggregation level {4, 8}, and in this example, has {4, 2} PDCCH candidates, respectively. The reason why the common search space supports only the aggregation level {4, 8} is to improve coverage characteristics since a system message should generally be delivered to a cell edge.
DCI transmitted in the common search space is defined for only a particular DCI format, such as 0/1A/3/3A/1C, which corresponds to a purpose of a system message, power control of a terminal group, or the like. A DCI format having spatial multiplexing is not supported in the common search space. In the UE-specific search space, a DL DCI format, which needs to be decoded, varies depending on a transmission mode configured for a corresponding terminal. The transmission mode is configured via RRC signaling, and thus an accurate subframe number as to whether the corresponding configuration is effective for the corresponding terminal is not designated. Therefore, the terminal may always perform decoding in relation to the DCI format 1A regardless of a transmission mode, and thus may operate not to lose communication.
