E-UTRA supports duplex modes of both FDD and TDD. While the interworking mechanisms between E-UTRA FDD and TDD have been specified, the behaviour of terminals simultaneously connected to the network on two (or more) bands with different duplex modes has not been specified. Efficient TDD and FDD spectrum usage and utilization of different technologies jointly are getting more and more important for the future LTE deployments in order to cope with increased throughput and capacity needs. This increases need for supporting joint LTE TDD-FDD joint operations such that both spectrum resources can be fully utilized to improve system performance and user experience. The use of carrier aggregation (CA) offers means to increase the peak data rates and throughput by aggregating, as has been discovered during Release 10 LTE CA work, and it has been enhanced during Release 11 LTE CA enhancement work. It is expected that in the future LTE FDD - TDD CA deployment scenarios either TDD or FDD cell may be as PCell and therefore, support for generic LTE FDD- TDD CA would be needed. At the 3GPP TSG RAN #60 meeting a new WI "LTE TDD - FDD Joint Operation" was agreed to start study and specify solutions to enhance LTE TDD - FDD joint operation depending on the outcome of the initial scenario evaluation phase of the work item. This document captures findings in the course of this discussion.

The present document contains a Study on FDD and TDD joint operation for E-UTRA and E-UTRAN. The objective of the present document is as follows:

• Identify deployment scenarios of joint operation on FDD and TDD spectrum, and network/UE requirement to support joint FDD/TDD operation;
• Based on the identified deployment scenarios and network/UE requirements, identify possible solutions for FDD-TDD joint operation.
• Based on the above, consider whether such solutions, if any, need to be added to the Work Item itself, or in separate Work Items.