Overview of uplink control channel for carrier aggregation enhancements in LTE Rel. 13

Frequency Spectrum is a non-renewable limited radio resource and therefore every effort has been made to efficiently utilize the spectrum. In LTE Release 10, 3GPP introduced carrier aggregation as a key enabler to meet the requirements set by IMT-Advanced by combining component carriers and have an aggregated bandwidth of up to 100 MHz. Further enhancements in LTE Rel. 11 and 12 have been introduced to support several configurations in time-division duplex and frequency-division duplex. Latest developments involve expanding carrier aggregation up to 32 component carriers in LTE Rel. 13. This would have challenging implications on the current control signaling support both in the downlink and uplink. In this paper, we identify the payload for uplink control information on physical uplink control channel to support carrier aggregation enhancements, analyze the limitations of existing formats and propose a simplified yet effective solution to provide reasonable support for transmitting uplink control information with larger payload.