Adaptive TDD UL/DL slot utilization for cellular controlled D2D communications

Cellular controlled Device-to-Device (D2D) system is a local service for future communication systems like LTE, LTE-A, etc. D2D communications can share the Uplink (UL) or Downlink (DL) resources with cellular communications to improve system throughput. Since reusing UL resource or DL resource has different merits in different scenarios, if D2D only reuses either UL or DL resource during the whole communication procedure, there may be some problems, such as load balance, interference, etc. This paper proposes a method for adaptively TDD UL/DL slot utilization for D2D communications according to the change of scenario in TD-LTE system. Analysis is made for illustrating our novel method and the advantages are listed.