Adapting a number of aggregation levels for control channel elements

摘要

Methods and apparatus are described for a base station to transmit and for a User Equipment (UE) to detect a Physical Downlink Control CHannel (PDCCH) conveying a Downlink Control Information (DCI) format scheduling data reception or data transmission by the UE. The base station transmits a PDCCH and the UE decodes candidate PDCCHs using a number of Control Channel Elements (CCEs) from a first set of CCEs for a first DCI format and using a number of CCEs from a second set of CCEs for a second DCI format depending on a maximum code rate for the DCI format transmission or on a scheduling bandwidth.

主权项

1. A method for a User Equipment (UE) to decode a Physical Downlink Control CHannel (PDCCH) that conveys a Downlink Control Information (DCI) format and is transmitted by a base station over a transmission time interval and with a modulation scheme in a number of Control Channel Elements (CCEs) from a set of CCEs that are located in one or more Physical Resource Block (PRB) pairs, each CCE including a number of available sub-carriers for PDCCH transmissions and each PRB pair including a number of sub-carriers over the transmission time interval, the method comprising:
determining a number of available sub-carriers in a CCE; decoding candidate PDCCHs for a first DCI format over a number of CCEs from a first set of CCEs, if a first code rate defined as a ratio of the first DCI format size to a product of the number of available sub-carriers and an order of a modulation scheme, is less than or equal to a value; decoding the candidate PDCCHs over a number of CCEs from a second set of CCEs if the first code rate is greater than the value; decoding candidate PDCCHs for a second DCI format over a number of CCEs from the first set of the CCEs, if a second code rate defined as a ratio of the second DCI format size to the product of the number of available sub-carriers and the order of the modulation scheme, is less than or equal to the value; and decoding the candidate PDCCHs over a number of CCEs from the second set of CCEs if the second code rate is greater than the value.