Next generation TDD cellular communication

The 4th generation (4G) LTE (Long Term Evolution) mainly focuses on spectrum assets on lower frequency bands. The next generation cellular communication would aim to develop utilization on higher frequency bands to fully utilize the spectrum assets on all frequency bands between 300MHz to 100GHz, with primary bands below 6GHz and complimentary bands above 6GHz. Time Division Duplex (TDD) is promising for spectrum assets above 3GHz due to no requirement for paired frequency band, channel reciprocity for Multiple-Input-Multiple- Output (MIMO) and cost-effectiveness. TDD will play an important role in the next generation cellular communication. In this paper, we provide views on the next generation TDD cellular communication. SOR (Service Oriented Radio), an enhanced air interface is developed, which can adapt to diverse requirements with high resource efficiency. TDD-U (TDD-Universal) frame structure, an enhanced TDD frame structure is developed, which can enable fast Sounding Reference Signal transmission and fast channel state information feedback for Massive MIMO, enable better utilization of dynamic TDD, enable short HARQ (Hybrid Automatic Repeat Request) RTT (Round Trip Time) and uniform HARQ timing, and enable low E2E latency. Moreover, MBC (Massive Beamforming for Control) is developed for control channel and common signals to improve the coverage.